2024-03-28T14:42:06Zhttps://www.repo.uni-hannover.de/oai/requestoai:www.repo.uni-hannover.de:123456789/192022-12-02T19:19:55Zcom_123456789_15col_123456789_16doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersionddc:020
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Heller, Lambert
author
Tullney, Marco
author
2014-10-24
Früher schrieben Forscherinnen und Forscher dicke Bücher. Heute kommt neues Wissen vor allem durch Aufsätze in Fachzeitschriften in die Welt – immer häufiger auch online. Das verheißt neue Chancen: Kolleginnen und Kollegen können die Texte leichter finden, schneller zitieren und verlinken. Worauf ist beim digitalen Publizieren zu achten?
Heller, Lambert; Tullney, Marco: Wissen auf einen Klick. In: duz Magazin (2014) Nr. 11, S. 69-71
http://www.repo.uni-hannover.de/handle/123456789/19
http://dx.doi.org/10.15488/1
open access
journals
scholarly communication
Open Access
Zeitschriften
Wissenschaftskommunikation
Wissen auf einen Klick
oai:www.repo.uni-hannover.de:123456789/202022-12-02T19:24:34Zcom_123456789_15col_123456789_16status-type:updatedVersionddc:340doc-type:Textdoc-type:ConferenceObjectopen_access
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Brehm, Elke
author
2012-08-12
TIB has set up a competence center for non-textual materials with the goal to collect, archive and present scientific audiovisual media among other non-textual material to its users via its portals. The acquisition of the necessary rights for the audiovisual media which enter into TIB´s collection profile is complex. The market for scientific information is international and does not end at national borders. Thus the scientific audiovisual media which TIB licenses are produced in Germany but also in other countries. Challenges are encountered regarding the German national law and, when collaborating with licensors from other countries, with other national laws. This paper aims at describing the legal framework within which TIB has to build up services and the challenges which TIB encounters when licensing electronic audiovisual media in Germany with a special focus on currently valid and new developments in European and German legal deposit and copyright law.
Brehm, Elke: Licensing of scientific audiovisual media in Germany : IFLA World Library and Information Congress, 78th IFLA General Conference and Assembly, 11-17 August 2012, Helsinki, Finland ; Paper und Vortrag der Session: 148 – Copyright law and legal deposit for audiovisual materials – Audiovisual and multimedia with Law Libraries. Helsinki : IFLA, 2012 URL: http://conference.ifla.org/past-wlic/2012/148-brehm-en.pdf
http://www.repo.uni-hannover.de/handle/123456789/20
http://dx.doi.org/10.15488/2
License
Audiovisual Media
Copyright
Legal Deposit
Open Access
Creative Commons
Germany
Open-Access-Lizenzen
Audiovisuelle Medien
Film
Lizenz
Urheberrecht
Pflichtexemplarrecht
Open Access
Creative Commons
Deutschland
Licensing of scientific audiovisual media in Germany
oai:www.repo.uni-hannover.de:123456789/212022-12-02T19:19:54Zcom_123456789_15col_123456789_16status-type:updatedVersionddc:830doc-type:Textdoc-type:Recensionopen_access
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Tempel, Bernhard
author
2002
Rezension des Katalogs zum Manuskriptnachlaß Gerhart Hauptmanns mit Hinweisen auf weitere Verzeichnisse des Hauptmann-Nachlasses (Briefnachlaß, Dokumente, Sammlung, Bibliothek) und von Nachlässen im Umfeld Hauptmanns (vor allem seiner zweiten Frau Margarete Hauptmann).
Tempel, Bernhard: [Rez. o.T. zu: Ziesche, Rudolf: Der Manuskriptnachlaß Gerhart Hauptmanns. Teil 3. GH Hs 471-780. Anhang 1-80 u. Teil 4. Register (Kataloge der Handschriftenabteilung / Staatsbibliothek zu Berlin – Preußischer Kulturbesitz: Reihe 2, Nachlässe 2, 3 u. 2, 4). Wiesbaden: Harrassowitz, 2000], in: Zeitschrift für deutsche Philologie 121 (2002), Nr. 2, S. 307-312
http://www.repo.uni-hannover.de/handle/123456789/21
http://dx.doi.org/10.15488/3
Hauptmann, Gerhart
Nachlass
Verzeichnis
[Rez. o.T. zu: Ziesche, Rudolf: Der Manuskriptnachlaß Gerhart Hauptmanns. Teil 3. GH Hs 471-780. Anhang 1-80 u. Teil 4. Register]
oai:www.repo.uni-hannover.de:123456789/222022-12-02T15:12:32Zcom_123456789_1col_123456789_7doc-type:Articledoc-type:Textopen_accessddc:530status-type:publishedVersion
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Baringhaus, Jens
author
Stöhr, Alexander
author
Forti, Stiven
author
Starke, Ulrich
author
Tegenkamp, Christoph
author
2015-04-21
The realization of ballistic graphene pn-junctions is an essential task in order to study Klein tunneling phenomena. Here we show that intercalation of Ge under the buffer layer of pre-structured SiC-samples succeeds to make truly nano-scaled pn-junctions. By means of local tunneling spectroscopy the junction width is found to be as narrow as 5 nm which is a hundred times smaller compared to electrically gated structures. The ballistic transmission across the junction is directly proven by systematic transport measurements with a 4-tip STM. Various npn- and pnp-junctions are studied with respect to the barrier length. The pn-junctions are shown to act as polarizer and analyzer with the second junction becoming transparent in case of a fully ballistic barrier. This can be attributed to the almost full suppression of electron transmission through the junction away from normal incidence.
Baringhaus, Jens; Stöhr, Alexander; Forti, Stiven; Starke, Ulrich; Tegenkamp, Christoph: Ballistic bipolar junctions in chemically gated graphene ribbons. In: Scientific Reports 5 (2015), Artikelnr. 9955. DOI: http://dx.doi.org/10.1038/srep09955
http://www.repo.uni-hannover.de/handle/123456789/22
http://dx.doi.org/10.15488/4
Surfaces
interfaces and thin films
Graphene
Electronic properties and devices
Graphen
Oberfläche
Ballistic bipolar junctions in chemically gated graphene ribbons
oai:www.repo.uni-hannover.de:123456789/232022-12-02T15:12:32Zcom_123456789_1col_123456789_7ddc:550doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersion
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Thosing, Korntip
author
Schrempf, Michael
author
Riechelmann, Stefan
author
Seckmeyer, Gunther
author
2014
Spectral sky radiance (380–760 nm) is derived from measurements with a hemispherical sky imager (HSI)system. The HSI consists of a commercial compact CCD (charge coupled device) camera equipped with a fish-eye lens and provides hemispherical sky images in three reference bands such as red, green and blue. To obtain the spectral sky radiance from these images, non-linear regression functions for various sky conditions have been derived. The camera-based spectral sky radiance was validated using spectral sky radiance measured with a CCD spectroradiometer. The spectral sky radiance for complete distribution over the hemisphere between both instruments deviates by less than 20% at 500 nm for all sky conditions and for zenith angles less than 80 . The reconstructed spectra of the wavelengths 380–760 nm between both instruments at various directions deviate by less than 20% for all sky conditions.
Tohsing, Korntip; Schrempf, Michael; Riechelmann, Stefan; Seckmeyer, Gunther: Validation of spectral sky radiance derived from all-sky camera images - a case study. In: Atmospheric Measurement Techniques 7 (2014), Nr. 7, S. 2137-2146. DOI:http://dx.doi.org/10.5194/amt-7-2137-2014
http://www.repo.uni-hannover.de/handle/123456789/23
http://dx.doi.org/10.15488/5
CCD Camera
Luminance Distributions
Field-Measurements
Optical-Properties
Irradiance
Algorithm
Skylight
View
CCD Kamera
Leuchtdichteverteilung
Feldmessung
Optische Eigenschaften
Strahlung
Algorithmus
Validation of spectral sky radiance derived from all-sky camera images - a case study
oai:www.repo.uni-hannover.de:123456789/242022-12-02T15:15:01Zcom_123456789_1col_123456789_7ddc:550doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersion
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Hofmann, Martin
author
Riechelmann, Stefan
author
Crisosto, Christian
author
Mubarak, Riyad
author
Seckmeyer, Gunther
author
2014-11-26
High resolution global irradiance time series are needed for accurate simulations of photovoltaic (PV) systems, since the typical volatile PV power output induced by fast irradiance changes cannot be simulated properly with commonly available hourly averages of global irradiance. We present a two-step algorithm that is capable of synthesizing one-minute global irradiance time series based on hourly averaged datasets. The algorithm is initialized by deriving characteristic transition probability matrices (TPM) for different weather conditions (cloudless, broken clouds and overcast) from a large number of high resolution measurements. Once initialized, the algorithm is location-independent and capable of synthesizing one-minute values based on hourly averaged global irradiance of any desired location. The one-minute time series are derived by discrete-time Markov chains based on a TPM that matches the weather condition of the input dataset. One-minute time series generated with the presented algorithm are compared with measured high resolution data and show a better agreement compared to two existing synthesizing algorithms in terms of temporal variability and characteristic frequency distributions of global irradiance and clearness index values. A comparison based on measurements performed in Lindenberg, Germany, and Carpentras, France, shows a reduction of the frequency distribution root mean square errors of more than 60% compared to the two existing synthesizing algorithms.
Hofmann, Martin; Riechelmann, Stefan; Crisosto, Christian; Mubarak, Riyad; Seckmeyer, Gunther: Improved Synthesis of Global Irradiance with One-Minute Resolution for PV System Simulations. In: International Journal of Photoenergy 2014 (2014), Artikel-Nr. 808509. DOI: http://dx.doi.org/10.1155/2014/808509
http://www.repo.uni-hannover.de/handle/123456789/24
http://dx.doi.org/10.15488/6
Radiation
Classification
Distributions
Temperature
Climate
Algorithm
Probability Density
Photovoltaic
Wahrscheinlichkeitsdichte
Radiation
Strahlung
Globalstrahlung
Klassifizierung
Verteilung
Temperatur
Klima
Algorithmus
Photovoltaik
Improved Synthesis of Global Irradiance with One-Minute Resolution for PV System Simulations
oai:www.repo.uni-hannover.de:123456789/252022-12-02T15:12:32Zcom_123456789_1col_123456789_7ddc:550doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersion
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Werkmeister, Astrid
author
Lockhoff, M.
author
Schrempf, Michael
author
Tohsing, Korntip
author
Liley, B.
author
Seckmeyer, Gunther
author
2015-05-06
In this case study we compare cloud fractional cover measured by radiometers on polar satellites (AVHRR) and on one geostationary satellite (SEVIRI) to ground-based manual (SYNOP) and automated observations by a cloud camera (Hemispherical Sky Imager, HSI). These observations took place in Hannover, Germany, and in Lauder, New Zealand, over time frames of 3 and 2 months, respectively. Daily mean comparisons between satellite derivations and the ground-based HSI found the deviation to be 6 14% for AVHRR and 8 16% for SEVIRI, which can be considered satisfactory. AVHRR’s instantaneous differences are smaller (2 22 %) than instantaneous SEVIRI cloud fraction estimates (8 29 %) when compared to HSI due to resolution and scenery effect issues. All spaceborne observations show a very good skill in detecting completely overcast skies (cloud cover 6 oktas) with probabilities between 92 and 94% and false alarm rates between 21 and 29% for AVHRR and SEVIRI in Hannover, Germany. In the case of a clear sky (cloud cover lower than 3 oktas) we find good skill with detection probabilities between 72 and 76 %. We find poor skill, however, whenever broken clouds occur (probability of detection is 32% for AVHRR and 12% for SEVIRI in Hannover, Germany). In order to better understand these discrepancies we analyze the influence of algorithm features on the satellite-based data. We find that the differences between SEVIRI and HSI cloud fractional cover (CFC) decrease (from a bias of 8 to almost 0 %) with decreasing number of spatially averaged pixels and decreasing index which determines the cloud coverage in each “cloud-contaminated” pixel of the binary map. We conclude that window size and index need to be adjusted in order to improve instantaneous SEVIRI and AVHRR estimates. Due to its automated operation and its spatial, temporal and spectral resolution, we recommend as well that more automated ground-based instruments in the form of cloud cameras should be installed as they cover larger areas of the sky than other automated ground-based instruments. These cameras could be an essential supplement to SYNOP observation as they cover the same spectral wavelengths as the human eye.
Werkmeister, A.; Lockhoff, M.; Schrempf, M.; Tohsing, K.; Liley, B.; Seckmeyer, G.: Comparing satellite- to ground-based automated and manual cloud coverage observations – a case study. In: Atmospheric Measurement Techniques 8 (2015), Nr. 5, S. 2001-2015. DOI: http://dx.doi.org/10.5194/amt-8-2001-2015
http://www.repo.uni-hannover.de/handle/123456789/25
http://dx.doi.org/10.15488/7
AVHRR Data
Clear-Sky
Part I
CM-SAF
Classification
Validation
Imagery
Radiation
Surface
Dynamic Thresholds
Dynamische Schwelle
AVHRR-Daten
klarer Himmel
CM-SAF
Klassifizierung
Validierung
Bild
Radiation
Strahlung
Oberfläche
Comparing satellite- to ground-based automated and manual cloud coverage observations – a case study
oai:www.repo.uni-hannover.de:123456789/262022-12-02T15:19:58Zcom_123456789_1col_123456789_8doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersionddc:580
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Peters, Katrin
author
Belt, Katharina
author
Braun, Hans-Peter
author
2013-06-04
Complex I has a unique structure in plants and includes extra subunits. Here, we present a novel study to define its protein constituents. Mitochondria were isolated from Arabidopsis thaliana cell cultures, leaves, and roots. Subunits of complex I were resolved by 3D blue-native (BN)/SDS/SDS-PAGE and identified by mass spectrometry. Overall, 55 distinct proteins were found, seven of which occur in pairs of isoforms. We present evidence that Arabidopsis complex I consists of 49 distinct types of subunits, 40 of which represent homologs of bovine complex I. The nine other subunits represent special proteins absent in the animal linage of eukaryotes, most prominently a group of subunits related to bacterial gamma-type carbonic anhydrases. A GelMap http://www.gelmap.de/arabidopsis-3d-complex-i/ is presented for promoting future complex I research in Arabidopsis thaliana.
Peters, Katrin; Belt, Katharina; Braun, Hans-Peter: 3D Gel Map of Arabidopsis Complex I. In: Frontiers in Plant Science 4 (2013), 153. DOI: http://dx.doi.org/10.3389/fpls.2013.00153
http://www.repo.uni-hannover.de/handle/123456789/26
http://dx.doi.org/10.15488/8
mitochondria
OXPHOS system
respiratory chain
NADH dehydrogenase
blue-native
BN/SDS/SDS-PAGE
Arabidopsis thaliana
Mitochondrium
Mitochondrion
OXPHOS-System
Oxidative Phosphorylierung
Atmungskette
NADH Dehydrogenase
Arabidopsis thaliana
Acker-Schmalwand
Blue-Native
3D Gel Map of Arabidopsis Complex I
oai:www.repo.uni-hannover.de:123456789/272022-12-02T15:19:58Zcom_123456789_1col_123456789_8doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersionddc:580
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Schertl, Peter
author
Braun, Hans-Peter
author
2014-04-29
The respiratory electron transport chain (ETC) couples electron transfer from organic substrates onto molecular oxygen with proton translocation across the inner mitochondrial membrane. The resulting proton gradient is used by the ATP synthase complex for ATP formation. In plants, the ETC is especially intricate. Besides the "classical" oxidoreductase complexes (complex I-IV) and the mobile electron transporters cytochrome c and ubiguinone, it comprises numerous "alternative oxidoreductases." Furthermore, several dehydrogenases localized in the mitochondrial matrix and the mitochondrial intermembrane space directly or indirectly provide electrons for the ETC. Entry of electrons into the system occurs via numerous pathways which are dynamically regulated in response to the metabolic state of a plant cell as well as environmental factors. This mini review aims to summarize recent findings on respiratory electron transfer pathways in plants and on the involved components and supramolecular assemblies.
Schertl, Peter; Braun, Hans-Peter: Respiratory electron transfer pathways in plant mitochondria. In: Frontiers in Plant Science 5 (2014), Artikel-Nr. 163. DOI: http://dx.doi.org/10.3389/fpls.2014.00163
http://www.repo.uni-hannover.de/handle/123456789/27
http://dx.doi.org/10.15488/9
plant mitochondria
mitochondria
electron transport chain
dehydrogenase
alternative oxidase
respiratory supercomplex
ETC
Pflanze
Mitochondrium
Mitochondrion
Elektronentransportkette
Dehydrogenase
alternative Oxidase
Atmungssuper-Komplex
Atmungskette
Superkomplex
Respiratory electron transfer pathways in plant mitochondria
oai:www.repo.uni-hannover.de:123456789/282022-12-02T16:11:41Zcom_123456789_1col_123456789_8doc-type:Articledoc-type:Textopen_accessddc:590status-type:publishedVersion
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Dreher, Corinna E.
author
Cummings, Molly E.
author
Pröhl, Heike
author
2015-06-25
Natural selection is widely noted to drive divergence of phenotypic traits. Predation pressure can facilitate morphological divergence, for example the evolution of both cryptic and conspicuous coloration in animals. In this context Dendrobatid frogs have been used to study evolutionary forces inducing diversity in protective coloration. The polytypic strawberry poison frog (Oophaga pumilio) shows strong divergence in aposematic coloration among populations. To investigate whether predation pressure is important for color divergence among populations of O. pumilio we selected four mainland populations and two island populations from Costa Rica and Panama. Spectrometric measurements of body coloration were used to calculate color and brightness contrasts of frogs as an indicator of conspicuousness for the visual systems of several potential predators (avian, crab and snake) and a conspecific observer. Additionally, we conducted experiments using clay model frogs of different coloration to investigate whether the local coloration of frogs is better protected than non-local color morphs, and if predator communities vary among populations. Overall predation risk differed strongly among populations and interestingly was higher on the two island populations. Imprints on clay models indicated that birds are the main predators while attacks of other predators were rare. Furthermore, clay models of local coloration were equally likely to be attacked as those of non-local coloration. Overall conspicuousness (and brightness contrast) of local frogs was positively correlated with attack rates by birds across populations. Together with results from earlier studies we conclude that conspicuousness honestly indicates toxicity to avian predators. The different coloration patterns among populations of strawberry poison frogs in combination with behavior and toxicity might integrate into equally efficient anti-predator strategies depending on local predation and other ecological factors.
Dreher, Corinna E.; Cummings, Molly E.; Pröhl, Heike: An Analysis of Predator Selection to Affect Aposematic Coloration in a Poison Frog Species. In: PLoS ONE 10 (2015), Nr. 6. DOI: http://dx.doi.org/10.1371/journal.pone.0130571
http://www.repo.uni-hannover.de/handle/123456789/28
http://dx.doi.org/10.15488/10
Dendrobates-Pumilio
Warning Signals
Oophaga-Pumilio
Natural-Selection
Sexual Selection
Visual Pigments
Fiddler-Crab
UCA-Tangeri
Body-Size
Conspicuousness
strawberry poison frog
Dendrobates pumilio
Oophaga pumilio
Warnsignal
Natürliche Selektion
Selektion
Sexuelle Selektion
Visuelle Pigmente
Winterkrabbe
Uca tangeri
Größe
Sichtbarkeit
Auffälligkeit
Erdbeerfrosch
An Analysis of Predator Selection to Affect Aposematic Coloration in a Poison Frog Species
oai:www.repo.uni-hannover.de:123456789/292022-12-02T16:10:14Zcom_123456789_1col_123456789_8doc-type:Articledoc-type:Textopen_accessddc:590status-type:publishedVersion
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Dreher, Corinna E.
author
Pröhl, Heike
author
2014-06-05
Sexual signals indicate species identity and mate quality, and their importance for mate attraction is largely recognized. Recently, research in animal communication has started to integrate multiple signal modalities and evaluate their interactions. However, mate choice experiments across animal taxa have been limited to laboratory conditions, and assessments of multiple sexual signals under field conditions are still lacking. We take advantage of the divergence in visual and acoustic signals among populations of the Neotropical poison frog Oophaga pumilio to evaluate the importance of male advertisement calls and color patterns in female mate selection. Previous mate choice experiments in this species suggested color-assortative female mate preferences across many populations. Nevertheless, acoustic signals are crucial for sexual selection in frogs, and males of O. pumilio use advertisement calls to attract females. We hypothesize that both advertisement calls and coloration affect female mate selection in O.pumilio. To test this hypothesis we tested 452 receptive females from six populations in Costa Rica and Panama in their natural home ranges for preferences regarding local vs. non-local advertisement calls and color patterns. Overall, the calls overrode the effect of coloration, whereby most females preferred local over non-local calls. We found a tendency to prefer brighter (but not necessarily local) males in two populations. Furthermore, the strength of preferences varied geographically, and thus might be involved in prezygotic isolation among populations. The stronger effect of calls on mate attraction is associated with acoustic divergence between genetic groups in the species, while color pattern diversity is mostly located within one genetic group, i.e., not linked to large-scale population structure. Finally our data highlights the importance to consider an array of signal modalities in multiple wild populations in studies of behavioral isolation.
Dreher, Corinna E.; Pröhl, Heike: Multiple sexual signals: calls over colors for mate attraction in an aposematic, color-diverse poison frog. Frontiers in Ecology and Evolution 2 (2014). DOI: http://dx.doi.org/10.3389/fevo.2014.00022
http://www.repo.uni-hannover.de/handle/123456789/29
http://dx.doi.org/10.15488/11
sexual selection
mate choice
prezygotic isolation
multiple sexual signals
playback experiments
poison frog
Oophaga pumilio
Dendrobates pumilio
strawberry poison frog
Evolution
Ecology
Oophaga pumilio
Dendrobates pumilio
Erdbeerfrosch
Sexuelle Selektion
Partnerwahl
Präzygotische Isolation
Multiple sexual signals: calls over colors for mate attraction in an aposematic, color-diverse poison frog
oai:www.repo.uni-hannover.de:123456789/302022-12-02T16:11:40Zcom_123456789_1col_123456789_8doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersionddc:580
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Ismaiel, Ahmed A.
author
Papenbrock, Jutta
author
2015-07-23
Mycotoxins are secondary fungal metabolites, toxic to humans, animals and plants. Among the hundreds of known mycotoxins, aflatoxins, citrinin, patulin, penicillic acid, tenuazonic acid, ochratoxin A, cytochalasins, deoxynivalenol, fumonisins, fusarin C, fusaric acid, and zearalenone are considered the types that most contaminate cereal grain. The majority of the mycotoxins in these groups are produced by three fungal genera: Aspergillus, Penicillium and Fusarium. These metabolites primarily affect the seed quality, germination, viability, seedling vigour, growth of root and cleoptile. Additionally, since the fungi responsible for the production of these mycotoxins are often endophytes that infect and colonize living plant tissues, accumulation of mycotoxins in the plant tissues may at times be associated with development of plant disease symptoms. The presence of mycotoxins, even in the absence of disease symptoms, may still have subtle biological effects on the physiology of plants. Several studies highlight the toxic effects of mycotoxins on animals and cell lines but little is known about the mode of action of most of these metabolites on plant cells. The most important mycotoxins with phytotoxic effects and their producers in addition to their discovery are briefly outlined below and will be addressed in this article.
Ismaiel, Ahmed Abdel; Papenbrock, Jutta: Mycotoxins: Producing Fungi and Mechanisms of Phytotoxicity. In: Agriculture 5 (2015), Nr. 3, S. 492-537. DOI: http://dx.doi.org/10.3390/agriculture5030492
http://www.repo.uni-hannover.de/handle/123456789/30
http://dx.doi.org/10.15488/12
mycotoxins
producing fungi
phytotoxicity
Mykotoxine
Pilz
Schimmelpilz
Phytotoxin
Mycotoxins: Producing Fungi and Mechanisms of Phytotoxicity
oai:www.repo.uni-hannover.de:123456789/312022-12-02T15:19:58Zcom_123456789_1col_123456789_8doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersionddc:580
00925njm 22002777a 4500
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Hastilestari, Bernadetta Rina
author
Mudersbach, Marina
author
Tomala, Filip
author
Vogt, Hartmut
author
Biskupek-Korell, Bettina
author
Damme, Patrick van
author
Guretzki, Sebastian
author
Papenbrock, Jutta
author
2013-05-03
Of late, decrease in mineral oil supplies has stimulated research on use of biomass as an alternative energy source. Climate change has brought problems such as increased drought and erratic rains. This, together with a rise in land degeneration problems with concomitant loss in soil fertility has inspired the scientific world to look for alternative bio-energy species. Euphorbia tirucalli L., a tree with C3/CAM metabolism in leaves/stem, can be cultivated on marginal, arid land and could be a good alternative source of biofuel. We analyzed a broad variety of E. tirucalli plants collected from different countries for their genetic diversity using AFLP. Physiological responses to induced drought stress were determined in a number of genotypes by monitoring growth parameters and influence on photosynthesis. For future breeding of economically interesting genotypes, rubber content and biogas production were quantified. Cluster analysis shows that the studied genotypes are divided into two groups, African and mostly non-African genotypes. Different genotypes respond significantly different to various levels of water. Malate measurement indicates that there is induction of CAM in leaves following drought stress. Rubber content varies strongly between genotypes. An investigation of the biogas production capacities of six E. tirucalli genotypes reveals biogas yields higher than from rapeseed but lower than maize silage.
Hastilestari, Bernadetta Rina; Mudersbach, Marina; Tomala, Filip; Vogt, Hartmut; Biskupek-Korell, Bettina; van Damme, Patrick; Guretzki, Sebastian; Papenbrock, Jutta: Euphorbia tirucalli L.–Comprehensive Characterization of a Drought Tolerant Plant with a Potential as Biofuel Source. In: PLoS ONE 8 (2013), Nr. 5. DOI: http://dx.doi.org/10.1371/journal.pone.0063501
http://www.repo.uni-hannover.de/handle/123456789/31
http://dx.doi.org/10.15488/13
Crassulacean acid metabolism
CAM
P-enolpyruvate carboxylase
Chlorophyll fluorescence
Mesembryanthemum crystallinum
Photosynthetic pathways
Stress
Expression
Malate
Energy
Crassulaceen-Säurestoffwechsel
CAM
Phosphoenolpyruvate-Carboxylase
Phosphoenolpyruvatcarboxylase
Chlorophyllfluoreszenz
Mesembryanthemum crystallinum
Eiskraut
Photosynthese
Stoffwechselweg
Stress
Malate
Energie
Euphorbia tirucalli L.–Comprehensive Characterization of a Drought Tolerant Plant with a Potential as Biofuel Source
oai:www.repo.uni-hannover.de:123456789/322022-12-02T16:10:14Zcom_123456789_1col_123456789_8doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersionddc:580
00925njm 22002777a 4500
dc
Nguyen, Vy X.
author
Detcharoen, Matsapume
author
Tuntiprapas, Piyalap
author
Soe-Htun, U.
author
Sidik, Japar B.
author
Harah, Muta Z.
author
Prathep, Anchana
author
Papenbrock, Jutta
author
2014
Background: The Indo-Pacific region has the largest number of seagrass species worldwide and this region is considered as the origin of the Hydrocharitaceae. Halophila ovalis and its closely-related species belonging to the Hydrocharitaceae are well-known as a complex taxonomic challenge mainly due to their high morphological plasticity. The relationship of genetic differentiation and geographic barriers of H. ovalis radiation was not much studied in this region. Are there misidentifications between H. ovalis and its closely related species? Does any taxonomic uncertainty among different populations of H. ovalis persist? Is there any genetic differentiation among populations in the Western Pacific and the Eastern Indian Ocean, which are separated by the Thai-Malay peninsula? Genetic markers can be used to characterize and identify individuals or species and will be used to answer these questions. Results: Phylogenetic analyses of the nuclear ribosomal internal transcribed spacer region based on materials collected from 17 populations in the Western Pacific and the Eastern Indian Ocean showed that some specimens identified as H. ovalis belonged to the H. major clade, also supported by morphological data. Evolutionary divergence between the two clades is between 0.033 and 0.038, much higher than the evolutionary divergence among H. ovalis populations. Eight haplotypes were found; none of the haplotypes from the Western Pacific is found in India and vice versa. Analysis of genetic diversity based on microsatellite analysis revealed that the genetic diversity in the Western Pacific is higher than in the Eastern Indian Ocean. The unrooted neighbor-joining tree among 14 populations from the Western Pacific and the Eastern Indian Ocean showed six groups. The Mantel test results revealed a significant correlation between genetic and geographic distances among populations. Results from band-based and allele frequency-based approaches from Amplified Fragment Length Polymorphism showed that all samples collected from both sides of the Thai-Malay peninsula were clustered into two clades: Gulf of Thailand and Andaman Sea. Conclusions: Our study documented the new records of H. major for Malaysia and Myanmar. The study also revealed that the Thai-Malay peninsula is a geographic barrier between H. ovalis populations in the Western Pacific and the Eastern Indian Ocean.
Nguyen, Vy X.; Detcharoen, Matsapume; Tuntiprapas, Piyalap; Soe-Htun, U.; Sidik, Japar B.; Harah, Muta Z.; Prathep, Anchana; Papenbrock, Jutta: Genetic species identification and population structure of Halophila (Hydrocharitaceae) from the Western Pacific to the Eastern Indian Ocean. In: BMC Evolutionary Biology 14 (2014) 92. DOI: http://dx.doi.org/10.1186/1471-2148-14-92
http://www.repo.uni-hannover.de/handle/123456789/32
http://dx.doi.org/10.15488/14
Eastern Indian Ocean
Evolution
Genetic distance
Halophila ovalis
Western Pacific Ocean
Seegrass
kleinblättriges Seegras
Indischer Ozean
Ostindischer Ozean
Pazifischer Ozean
Westpazifik
Halophila ovalis
Genetische Distanz
Evolution
Seegras
Genetic species identification and population structure of Halophila (Hydrocharitaceae) from the Western Pacific to the Eastern Indian Ocean
oai:www.repo.uni-hannover.de:123456789/332022-12-02T16:11:41Zcom_123456789_1col_123456789_8doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersionddc:580
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Hirschmann, Felix
author
Krause, Florian
author
Papenbrock, Jutta
author
2014
All members of the sulfotransferase (SOT, EC 2.8.2.-) protein family transfer a sulfuryl group from the donor 3’-phosphoadenosine 5’-phosphosulfate (PAPS) to an appropriate hydroxyl group of several classes of substrates. The primary structure of these enzymes is characterized by a histidine residue in the active site, defined PAPS binding sites and a longer SOT domain. Proteins with this SOT domain occur in all organisms from all three domains, usually as a multi-protein family. Arabidopsis thaliana SOTs, the best characterized SOT multi-protein family, contains 21 members. The substrates for several plant enzymes have already been identified, such as glucosinolates, brassinosteroids, jasmonates, flavonoids, and salicylic acid. Much information has been gathered on desulfoglucosinolate (dsGl) SOTs in A. thaliana. The three cytosolic dsGI SOTs show slightly different expression patterns. The recombinant proteins reveal differences in their affinity to indolic and aliphatic dsGls. Also the respective recombinant dsGl SOTs from different A. thaliana ecotypes differ in their kinetic properties. However, determinants of substrate specificity and the exact reaction mechanism still need to be clarified. Probably, the three-dimensional structures of more plant proteins need to be solved to analyze the mode of action and the responsible amino acids for substrate binding. In addition to A. thaliana, more plant species from several families need to be investigated to fully elucidate the diversity of sulfated molecules and the way of biosynthesis catalyzed by SOT enzymes.
Hirschmann, Felix; Krause, Florian; Papenbrock, Jutta: The multi-protein family of sulfotransferases in plants: composition, occurrence, substrate specificity, and functions. In: Frontiers in Plant Science 5 (2014). DOI: http://dx.doi.org/10.3389/fpls.2014.00556
http://www.repo.uni-hannover.de/handle/123456789/33
http://dx.doi.org/10.15488/15
Arabidopsis thaliana
glucosinolate
histidine residue
phosphoadenosine 5 ‘-phosphosulfate
Sulfotransferase
Arabidopsis thaliana
Ackerschmalwand
Brassicaceae
Kreuzblütengewächs
Glucosinolate
Senfölglycoside
Histidin
3’-phosphoadenosine 5’-phosphosulfate
PAPS
Sulfotransferasen
The multi-protein family of sulfotransferases in plants: composition, occurrence, substrate specificity, and functions
oai:www.repo.uni-hannover.de:123456789/342022-12-02T16:11:41Zcom_123456789_1col_123456789_8doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersionddc:580
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Weese, Annekathrin
author
Pallmann, Philip
author
Papenbrock, Jutta
author
Riemenschneider, Anja
author
2015
Under adequate sulfur supply, plants accumulate sulfate in the vacuoles and use sulfur-containing metabolites as storage compounds. Under sulfur-limiting conditions, these pools of stored sulfur-compounds are depleted in order to balance the nitrogen to sulfur ratio for protein synthesis. Stress conditions like sulfur limitation and/or pathogen attack induce changes in the sulfate pool and the levels of sulfur-containing metabolites, which often depend on the ecotypes or cultivars. We are interested in investigating the influence of the genetic background of canola (Brassica napus) cultivars in sulfur-limiting conditions on the resistance against Verticillium longisporum. Therefore, four commercially available Brassica. napus cultivars were analyzed. These high-performing cultivars differ in some characteristics described in their cultivar pass, such as several agronomic traits, differences in the size of the root system, and resistance to certain pathogens, such as Phoma and Verticillium. The objectives of the study were to examine and explore the patterns of morphological, physiological and metabolic diversity in these Brassica. napus cultivars at different sulfur concentrations and in the context of plant defense. Results indicate that the root systems are influenced differently by sulfur deficiency in the cultivars. Total root dry mass and length of root hairs differ not only among the cultivars but also vary in their reaction to sulfur limitation and pathogen attack. As a sensitive indicator of stress, several parameters of photosynthetic activity determined by PAM imaging showed a broad variability among the treatments. These results were supported by thermographic analysis. Levels of sulfur-containing metabolites also showed large variations. The data were interrelated to predict the specific behavior during sulfur limitation and/or pathogen attack. Advice for farming are discussed.
Weese, Annekathrin; Pallmann, Philip; Papenbrock, Jutta; Riemenschneider, Anja: Brassica napus L. cultivars show a broad variability in their morphology, physiology and metabolite levels in response to sulfur limitations and to pathogen attack. In: Frontiers in Plant Science 6 (2015), 9. DOI: http://dx.doi.org/10.3389/fpls.2015.00009
http://www.repo.uni-hannover.de/handle/123456789/34
http://dx.doi.org/10.15488/16
canola
diurnal rhythm
elemental sulfur
metabolites
Verticillium longisporum
Raps
Canola
Tagesrhythmus
Schwefel
Abbauprodukt
Stoffwechselprodukt
Verticillium longisporum
Brassica napus L. cultivars show a broad variability in their morphology, physiology and metabolite levels in response to sulfur limitations and to pathogen attack
oai:www.repo.uni-hannover.de:123456789/352022-12-02T16:11:41Zcom_123456789_1col_123456789_8doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersionddc:580
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Boestfleisch, Christian
author
Wagenseil, Niko B.
author
Buhmann, Anne K.
author
Seal, Charlotte E.
author
Wade, Ellie Merrett
author
Muscolo, Adele
author
Papenbrock, Jutta
author
2014
Halophytes, salt-tolerant plants, are a source of valuable secondary metabolites with potential economic value. The steady-state pools of many stress-related metabolites are already enhanced in halophytes when compared with glycophytes, but growth under conditions away from the optimum can induce stress and consequently result in changes to secondary metabolites such as antioxidants. However, direct evidence for increasing the concentration of valuable secondary metabolites as a consequence of altering the salinity of the growing environment still remains equivocal. To address this, we analysed a range of metabolites with antioxidant capacity (including total phenols, flavonoids, ascorbate, reduced/oxidized glutathione and reactive oxygen species scavenging enzymes) in seedlings and plants from different families (Amaranthaceae, Brassicaceae, Plantaginaceae and Rhizophoraceae) and habitats grown under different salt concentrations. We show that it is possible to manipulate the antioxidant capacity of plants and seedlings by altering the saline growing environment, the length of time under saline cultivation and the developmental stage. Among the species studied, the halophytes Tripolium pannonicum, Plantago coronopus, Lepidium latifolium and Salicornia europaea demonstrated the most potential as functional foods or nutraceuticals.
Boestfleisch, Christian; Wagenseil, Niko B.; Buhmann, Anne K.; Seal, Charlotte E.; Wade, Ellie Merrett; Muscolo, Adele; Papenbrock, Jutta:
Manipulating the antioxidant capacity of halophytes to increase their cultural and economic value through saline cultivation. In: AoB PLANTS 6 (2014). DOI: http://dx.doi.org/10.1093/aobpla/plu046
http://www.repo.uni-hannover.de/handle/123456789/35
http://dx.doi.org/10.15488/17
Halophytes
nutraceuticals
secondary metabolites
stress tolerance
yield
Salzpflanze
Halophyt
Nutraceutical
Sekundärstoffwechselprodukt
Stresstoleranz
Manipulating the antioxidant capacity of halophytes to increase their cultural and economic value through saline cultivation
oai:www.repo.uni-hannover.de:123456789/362022-12-02T16:11:41Zcom_123456789_1col_123456789_8doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersionddc:580
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Singh, Devesh
author
Buhmann, Anne K.
author
Flowers, Tim J.
author
Seal, Charlotte E.
author
Papenbrock, Jutta
author
2014
Rising sea levels and salinization of groundwater due to global climate change result in fast-dwindling sources of freshwater. Therefore, it is important to find alternatives to grow food crops and vegetables. Halophytes are naturally evolved salt-tolerant plants that are adapted to grow in environments that inhibit the growth of most glycophytic crop plants substantially. Members of the Salicornioideae are promising candidates for saline agriculture due to their high tolerance to salinity. Our aim was to develop genetically characterized lines of Salicornia and Sarcocornia for further breeding and to determine optimal cultivation conditions. To obtain a large and diverse genetic pool, seeds were collected from different countries and ecological conditions. The external transcribed spacer (ETS) sequence of 62 Salicornia and Sarcocornia accessions was analysed: ETS sequence data showed a clear distinction between the two genera and between different Salicornia taxa. However, in some cases the ETS was not sufficiently variable to resolve morphologically distinct species. For the determination of optimal cultivation conditions, experiments on germination, seedling establishment and growth to a harvestable size were performed using different accessions of Salicornia spp. Experiments revealed that the percentage germination was greatest at lower salinities and with temperatures of 20/10 degrees C (day/night). Salicornia spp. produced more harvestable biomass in hydroponic culture than in sand culture, but the nutrient concentration requires optimization as hydroponically grown plants showed symptoms of stress. Salicornia ramosissima produced more harvestable biomass than Salicornia dolichostachya in artificial sea water containing 257 mM NaCl. Based on preliminary tests on ease of cultivation, gain in biomass, morphology and taste, S. dolichostachya was investigated in more detail, and the optimal salinity for seedling establishment was found to be 100 mM. Harvesting of S. dolichostachya twice in a growing season was successful, but the interval between the harvests needs to be optimized to maximize biomass production.
Singh, Devesh; Buhmann, Anne K.; Flowers, Tim J.; Seal, Charlotte E.; Papenbrock, Jutta: Salicornia as a crop plant in temperate regions: selection of genetically characterized ecotypes and optimization of their cultivation conditions. In: AoB PLANTS 6 (2014). DOI: http://dx.doi.org/10.1093/aobpla/plu071
http://www.repo.uni-hannover.de/handle/123456789/36
http://dx.doi.org/10.15488/18
Biomass
ETS
germination
Salicornia species
salinity
External transcribed spacer
Salicornica
Biomasse
ETS
Keimung
Salicornia
Amaranthaceae
Salicornia as a crop plant in temperate regions: selection of genetically characterized ecotypes and optimization of their cultivation conditions
oai:www.repo.uni-hannover.de:123456789/372022-12-02T15:19:58Zcom_123456789_1col_123456789_8doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersionddc:580
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Lucas, Christina
author
Thangaradjou, Thirunavakkarasu
author
Papenbrock, Jutta
author
2012
Seagrasses, a unique group of submerged flowering plants, profoundly influence the physical, chemical and biological environments of coastal waters through their high primary productivity and nutrient recycling ability. They provide habitat for aquatic life, alter water flow, stabilize the ground and mitigate the impact of nutrient pollution. at the coast region. Although on a global scale seagrasses represent less than 0.1% of the angiosperm taxa, the taxonomical ambiguity in delineating seagrass species is high. Thus, the taxonomy of several genera is unsolved. While seagrasses are capable of performing both, sexual and asexual reproduction, vegetative reproduction is common and sexual progenies are always short lived and epimeral in nature. This makes species differentiation often difficult, especially for non-taxonomists since the flower as a distinct morphological trait is missing. Our goal is to develop a DNA barcoding system assisting also non-taxonomists to identify regional seagrass species. The results will be corroborated by publicly available sequence data. The main focus is on the 14 described seagrass species of India, supplemented with seagrasses from temperate regions. According to the recommendations of the Consortium for the Barcoding of Life (CBOL) rbcL and matK were used in this study. After optimization of the DNA extraction method from preserved seagrass material, the respective sequences were amplified from all species analyzed. Tree-and character-based approaches demonstrate that the rbcL sequence fragment is capable of resolving up to family and genus level. Only matK sequences were reliable in resolving species and partially the ecotype level. Additionally, a plastidic gene spacer was included in the analysis to confirm the identification level. Although the analysis of these three loci solved several nodes, a few complexes remained unsolved, even when constructing a combined tree for all three loci. Our approaches contribute to the understanding of the morphological plasticity of seagrasses versus genetic differentiation.
Lucas, Christina; Thangaradjou, Thirunavakkarasu; Papenbrock, Jutta: Development of a DNA Barcoding System for Seagrasses: Successful but Not Simple. In: PLoS ONE 7 (2012), Nr. 1. DOI: http://dx.doi.org/10.1371/journal.pone.0029987
http://www.repo.uni-hannover.de/handle/123456789/37
http://dx.doi.org/10.15488/19
Land Plants
Seagrass
Reticulate evolution
Zosteric acid
Sequence data
New Zealand
Phylogeny
Hydrocharitaceae
Identification
Diversity
Taxonomy
Seegras
Retikulate Evolution
Vernetzte Evolution
Sequenzdaten
Phylogenese
Abstammung
Neuseeland
Identifizierung
Vielfalt
Diversität
Hydrocharitaceae
Froschbissgewächse
Taxonomie
Klassifikation
Development of a DNA Barcoding System for Seagrasses: Successful but Not Simple
oai:www.repo.uni-hannover.de:123456789/382022-12-02T15:19:58Zcom_123456789_1col_123456789_8doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersionddc:580
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Remelli, William
author
Guerrieri, Nicoletta
author
Klodmann, Jennifer
author
Papenbrock, Jutta
author
Pagani, Silvia
author
Forlani, Fabio
author
2012
The phenotypic features of the Azotobacter vinelandii RhdA mutant MV474 (in which the rhdA gene was deleted) indicated that defects in antioxidant systems in this organism were related to the expression of the tandem-domain rhodanese RhdA. In this work, further insights on the effects of the oxidative imbalance generated by the absence of RhdA (e.g. increased levels of lipid hydroperoxides) are provided. Starting from the evidence that glutathione was depleted in MV474, and using both in silico and in vitro approaches, here we studied the interaction of wild-type RhdA and Cys(230) Ala site-directed RhdA mutant with glutathione species. We found that RhdA was able to bind in vitro reduced glutathione (GSH) and that RhdA-Cys(230) residue was mandatory for the complex formation. RhdA catalyzed glutathione-disulfide formation in the presence of a system generating the glutathione thiyl radical (GS(.), an oxidized form of GSH), thereby facilitating GSH regeneration. This reaction was negligible when the Cys230 Ala RhdA mutant was used. The efficiency of RhdA as catalyst in GS(.)-scavenging activity is discussed on the basis of the measured parameters of both interaction with glutathione species and kinetic studies.
Remelli, William; Guerrieri, Nicoletta; Klodmann, Jennifer; Papenbrock, Jutta; Pagani, Silvia; Forlani, Fabio: Involvement of the Azotobacter vinelandii Rhodanese-Like Protein RhdA in the Glutathione Regeneration Pathway. In: PLoS ONE 7 (2012), Nr. 9. DOI: http://dx.doi.org/10.1371/journal.pone.0045193
http://www.repo.uni-hannover.de/handle/123456789/38
http://dx.doi.org/10.15488/20
RhdA
Rhodanese-like proteins
Azotobacter vinelandii
Glutathione
Oxidative stress
Thiyl radicals
Settore BIO/10 - Biochimica
Glutathion
RhdA
Rhodanese
Azotobacter vinelandii
Oxidativer Stress
Glutathion
Involvement of the Azotobacter vinelandii Rhodanese-Like Protein RhdA in the Glutathione Regeneration Pathway
oai:www.repo.uni-hannover.de:123456789/392022-12-02T18:18:51Zcom_123456789_1col_123456789_8doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersionddc:580
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Hogekamp, Claudia
author
Küster, Helge
author
2013-05-07
Background: About 80% of today's land plants are able to establish an arbuscular mycorrhizal (AM) symbiosis with Glomeromycota fungi to improve their access to nutrients and water in the soil. On the molecular level, the development of AM symbioses is only partly understood, due to the asynchronous development of the microsymbionts in the host roots. Although many genes specifically activated during fungal colonization have been identified, genome-wide information on the exact place and time point of their activation remains limited. Results: In this study, we relied on a combination of laser-microdissection and the use of Medicago GeneChips to perform a genome-wide analysis of transcription patterns in defined cell-types of Medicago truncatula roots mycorrhized with Glomus intraradices. To cover major stages of AM development, we harvested cells at 5-6 and at 21 days post inoculation (dpi). Early developmental stages of the AM symbiosis were analysed by monitoring gene expression in appressorial and non-appressorial areas from roots harbouring infection units at 5-6 dpi. Here, the use of laser-microdissection for the first time enabled the targeted harvest of those sites, where fungal hyphae first penetrate the root. Circumventing contamination with developing arbuscules, we were able to specifically detect gene expression related to early infection events. To cover the late stages of AM formation, we studied arbusculated cells, cortical cells colonized by intraradical hyphae, and epidermal cells from mature mycorrhizal roots at 21 dpi. Taken together, the cell-specific expression patterns of 18014 genes were revealed, including 1392 genes whose transcription was influenced by mycorrhizal colonization at different stages, namely the pre-contact phase, the infection of roots via fungal appressoria, the subsequent colonization of the cortex by fungal hyphae, and finally the formation of arbuscules. Our cellular expression patterns identified distinct groups of AM-activated genes governing the sequential reprogramming of host roots towards an accommodation of microsymbionts, including 42 AM-activated transcription factor genes. Conclusions: Our genome-wide analysis provides novel information on the cell-specific activity of AM-activated genes during both early and late stages of AM development, together revealing the road map of fine-tuned adjustments of transcript accumulation within root tissues during AM fungal colonization.
Hogekamp, Claudia; Küster, Helge: A roadmap of cell-type specific gene expression during sequential stages of the arbuscular mycorrhiza symbiosis. In: BMC Genomics 14 (2013), Nr. 1. DOI: http://dx.doi.org/10.1186/1471-2164-14-306
http://www.repo.uni-hannover.de/handle/123456789/39
http://dx.doi.org/10.15488/21
Arbuscular mycorrhizal symbiosis
Cellular expression profiling
Laser-microdissection
Medicago GeneChips
Sequential reprogramming
Transcriptional regulators
Arbuskuläre Mykorrhizapilze
Genexpressionsanalyse
Expressionsprofil
Laser-Mikrodissektion
Lasermikrodissektion
Medicago GeneChip
Schneckenklee
A roadmap of cell-type specific gene expression during sequential stages of the arbuscular mycorrhiza symbiosis
oai:www.repo.uni-hannover.de:123456789/402022-12-02T15:15:01Zcom_123456789_1col_123456789_7doc-type:Articledoc-type:Textopen_accessddc:530status-type:publishedVersion
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Pfullmann, N.
author
Waltermann, C.
author
Noack, M.
author
Rausch, S.
author
Nagy, T.
author
Reinhardt, C.
author
Kovacev, M.
author
Knittel, V.
author
Bratschitsch, R.
author
Akemeier, D.
author
Huetten, A.
author
Leitenstorfer, A.
author
Morgner, Uwe
author
2013
We report on the generation of extreme ultraviolet radiation utilizing the plasmonic field enhancement in arrays of bow-tie gold optical antennae. Furthermore, their suitability to support high-order harmonic generation is examined by means of finite-difference time-domain calculations and experiments. Particular emphasis is paid to the thermal properties, which become significant at the employed peak intensities. A damage threshold depending on the antenna length is predicted and confirmed by our experimental findings. Moreover, the gas density in the vicinity of the antennae is characterized experimentally to determine the number of atoms contributing to the measured radiation, which is almost an order of magnitude larger than previously reported.
Pfullmann, N.; Waltermann, C. Noack M.; Rausch, S.; Nagy, T.; Reinhardt, C.; Kovacev, M.; Knittel, V.; Bratschitsch, R.; Akemeier, D.; Huetten, A.; Leitenstorfer, A.; Morgner, U.: Bow-tie nano-antenna assisted generation of extreme ultraviolet radiation. In: New Journal of Physics 15 (2013), Nr. 9. DOI: http://dx.doi.org/10.1088/1367-2630/15/9/093027
http://www.repo.uni-hannover.de/handle/123456789/40
http://dx.doi.org/10.15488/22
laser oscillator
plasmonics
high-harmonic generation
bow-tie antennae
Bow-tie nano-antenna assisted generation of extreme ultraviolet radiation
oai:www.repo.uni-hannover.de:123456789/412022-12-02T15:02:16Zcom_123456789_1col_123456789_2ddc:550doc-type:Articledoc-type:Textopen_accessddc:590status-type:publishedVersionddc:570
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Sybertz, Janine
author
Reich, Michael
author
2015
It is crucial to define and quantify possible impacts of climate change on wildlife in order to be able to pre-adapt management strategies for nature conservation. Thus, it is necessary to assess which species might be affected by climatic changes, especially at the regional scale. We present a novel approach to estimate possible climate change induced turnovers in bird communities and apply this method to Lüneburg Heath, a region in northern Germany. By comparing species pools of future climatically analogous regions situated in France with the Lüneburg Heath species pool, we detected possible trends for alterations within the regional bird community in the course of climate change. These analyses showed that the majority of bird species in Lüneburg Heath will probably be able to tolerate the projected future climate conditions, but that bird species richness, in general, may decline. Species that might leave the community were often significantly associated with inland wetland habitats, but the proportion of inland wetlands within the regions had a significant influence on the magnitude of this effect. Our results suggest that conservation efforts in wetlands have to be strengthened in light of climate change because many species are, in principle, able to tolerate future climate conditions if sufficient habitat is available.
Sybertz, Janine; Reich, Michael: Assessing Climate Change Induced Turnover in Bird Communities Using Climatically Analogous Regions. In: Diversity 7 (2015), Nr. 1, S. 36-59. DOI: http://dx.doi.org/10.3390/d7010036
http://www.repo.uni-hannover.de/handle/123456789/41
http://dx.doi.org/10.15488/23
breeding birds
analogous climates
climate change projections
nature conservation
Lüneburg Heath
Lüneburger Heide
Brutvögel
Klimawandel
Assessing Climate Change Induced Turnover in Bird Communities Using Climatically Analogous Regions
oai:www.repo.uni-hannover.de:123456789/422022-12-02T16:11:41Zcom_123456789_1col_123456789_8doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersionddc:570
00925njm 22002777a 4500
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Taubert, Johannes
author
Hou, Bo
author
Risselada, H. Jelger
author
Mehner, Denise
author
Lünsdorf, Heinrich
author
Grubmüller, Helmut
author
Brüser, Thomas
author
2015
The Tat system can transport folded, signal peptide-containing proteins (Tat substrates) across energized membranes of prokaryotes and plant plastids. A twin-arginine motif in the signal peptide of Tat substrates is recognized by TatC-containing complexes, and TatA permits the membrane passage. Often, as in the model Tat systems of Escherichia coli and plant plastids, a third component-TatB-is involved that resembles TatA but has a higher affinity to TatC. It is not known why most TatA dissociates from TatBC complexes in vivo and distributes more evenly in the membrane. Here we show a TatBC-independent substrate-binding to TatA from Escherichia coli, and we provide evidence that this binding enhances Tat transport. First hints came from in vivo cross-linking data, which could be confirmed by affinity co-purification of TatA with the natural Tat substrates HiPIP and NrfC. Two positions on the surface of HiPIP could be identified that are important for the TatA interaction and transport efficiency, indicating physiological relevance of the interaction. Distributed TatA thus may serve to accompany membrane-interacting Tat substrates to the few TatBC spots in the cells.
Taubert, Johannes; Hou, Bo; Risselada, H. Jelger; Mehner, Denise; Lünsdorf, Heinrich; Grubmüller, Helmut; Brüser, Thomas: TatBC-Independent TatA/Tat Substrate Interactions Contribute to Transport Efficiency. In: PLOS ONE 10 (2015), Nr. 3. DOI: http://dx.doi.org/10.1371/journal.pone.0119761
http://www.repo.uni-hannover.de/handle/123456789/42
http://dx.doi.org/10.15488/24
twin-arginine translocation
dependent protein-transport
coli plasma-membrane
Escherichia-coli
signal peptide
Streptomyces-lividans
pathway specificit
precursor proteins
Bacillus-subtilis
binding-site
TatBC-Independent TatA/Tat Substrate Interactions Contribute to Transport Efficiency
oai:www.repo.uni-hannover.de:123456789/432022-12-02T15:15:01Zcom_123456789_1col_123456789_7doc-type:Articledoc-type:Textopen_accessddc:530status-type:publishedVersion
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Krieg, U.
author
Lichtenstein, T.
author
Brand, C.
author
Tegenkamp, Christoph
author
Pfnür, Herbert
author
2015
We investigated the metallicity of Ag-root 3 ordered atomic wires close to one monolayer (ML) coverage, which are formed on Si(557) via self assembly. For this purpose we combined high resolution electron energy loss spectroscopy with tunneling microscopy. By extending the excess Ag coverage up to 0.6 ML on samples annealed at high temperatures where partial desorption occurs, we demonstrate that one-dimensional metallicity in the Ag-root 3 x root 3 R30 degrees ordered atomic wires on the (111) mini-terraces originates only from Ag atoms in excess of (local) monolayer coverage, which are adsorbed and localized at the highly stepped parts of the Si(557) surface. Thus these Ag atoms act as extrinsic dopants on the atomic scale, causing coverage dependent subband filling and increasing localization as a function of doping concentration. The second layer lattice gas as well as Ag islands on the (111) terraces turn out not to be relevant as dopants. We simulated the peculiar saturation behavior within a modified lattice gas model and give evidence that the preparation dependent saturation of doping is due to changes of average terrace size and step morphology induced by high temperature treatment.
Krieg, U.; Lichtenstein, T.; Brand, C.; Tegenkamp, C.; Pfnuer, H.: Origin of metallicity in atomic Ag wires on Si(557). In: New Journal of Physics 17 (2015). DOI: http://dx.doi.org/10.1088/1367-2630/17/4/043062
http://www.repo.uni-hannover.de/handle/123456789/43
http://dx.doi.org/10.15488/25
plasmons in one dimension
wire doping
high resolution electron loss spectroscopy
tunelling microscopy
one-dimensional plasmons
plasmon
monolayer
doping
Ag
silicon
Si
surface
Plasmon
eindimensionale Plasmonen
1D-Plasmonen
Monoschicht
Silber
Ag
Si
Silicium
silver
Origin of metallicity in atomic Ag wires on Si(557)
oai:www.repo.uni-hannover.de:123456789/442022-12-02T15:15:01Zcom_123456789_1col_123456789_7ddc:550doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersion
00925njm 22002777a 4500
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Heinze, Rieke
author
Mironov, Dmitrii
author
Raasch, Siegfried
author
2015
A detailed analysis of second-order moment budgets for cloud topped boundary layers (CTBLs) is performed using high-resolution large-eddy simulation (LES). Two CTBLs are simulated—one with trade wind shallow cumuli, and the other with nocturnal marine stratocumuli. Approximations to the ensemble-mean budgets of the Reynolds-stress components, of the fluxes of two quasi-conservative scalars, and of the scalar variances and covariance are computed by averaging the LES data over horizontal planes and over several hundred time steps. Importantly, the subgrid scale contributions to the budget terms are accounted for. Analysis of the LES-based second-moment budgets reveals, among other things, a paramount importance of the pressure scrambling terms in the Reynolds-stress and scalar-flux budgets. The pressure-strain correlation tends to evenly redistribute kinetic energy between the components, leading to the growth of horizontal-velocity variances at the expense of the vertical-velocity variance which is produced by buoyancy over most of both CTBLs. The pressure gradient-scalar covariances are the major sink terms in the budgets of scalar fluxes. The third-order transport proves to be of secondary importance in the scalar-flux budgets. However, it plays a key role in maintaining budgets of TKE and of the scalar variances and covariance. Results from the second-moment budget analysis suggest that the accuracy of description of the CTBL structure within the second-order closure framework strongly depends on the fidelity of parameterizations of the pressure scrambling terms in the flux budgets and of the third-order transport terms in the variance budgets.
Heinze, Rieke; Mironov, Dmitrii; Raasch, Siegfried: Second-moment budgets in cloud topped boundary layers: A large-eddy simulation study. In: Journal of Advances in Modeling Earth Systems 7 (2015), Nr. 2, S. 510-536. DOI: http://dx.doi.org/10.1002/2014MS000376
http://www.repo.uni-hannover.de/handle/123456789/44
http://dx.doi.org/10.15488/26
large-eddy simulation
cloud topped boundary layers
atmospheric turbulence
modeling
parameterizations
second-moment budgets
LES
boundary layer process
Subgrid-scale parameterization
SGS
large eddy simulation
Grobstruktursimulation
Large Eddy Simulation
LES
Meteorlogie
Atmosphärische Turbulenz
Parametrisierung
Grenzschichtprozess
Second-moment budgets in cloud topped boundary layers: A large-eddy simulation study
oai:www.repo.uni-hannover.de:123456789/452022-12-02T15:15:01Zcom_123456789_1col_123456789_7ddc:550doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersion
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dc
Maronga, Björn
author
Gryschka, Micha
author
Heinze, Rieke
author
Hoffmann, Fabian
author
Kanani-Sühring, Farah
author
Keck, Marius
author
Ketelsen, K.
author
Letzel, M.O.
author
Sühring, Matthias
author
Raasch, Siegfried
author
2015-02-19
In this paper we present the current version of the Parallelized Large-Eddy Simulation Model (PALM) whose core has been developed at the Institute of Meteorology and Climatology at Leibniz Universität Hannover (Germany). PALM is a Fortran 95-based 5 code with some Fortran 2003 extensions and has been applied for the simulation of a variety of atmospheric and oceanic boundary layers for more than 15 years. PALM is optimized for use on massively parallel computer architectures and was recently ported to general-purpose graphics processing units. In the present paper we give a detailed description of the current version of the model and its features, such as an embedded 10 Lagrangian cloud model and the possibility to use Cartesian topography. Moreover, we discuss recent model developments and future perspectives for LES applications.
Maronga, B.; Gryschka, M.; Heinze, R.; Hoffmann, F.; Kanani-Sühring, F.; Keck, M.; Ketelsen, K.; Letzel, M. O.; Sühring, M.; Raasch, S.: The Parallelized Large-Eddy Simulation Model (PALM) version 4.0 for atmospheric and oceanic flows: model formulation, recent developments, and future perspectives. In: Geoscientific Model Development Discussions 8 (2015), Nr. 2, S. 1539-1637. DOI: http://dx.doi.org/10.5194/gmdd-8-1539-2015
http://www.repo.uni-hannover.de/handle/123456789/45
http://dx.doi.org/10.15488/27
large eddy simulation
large-eddy simulation
LES
PALM
meteorology
Software
Large Eddy Simulation
LES
Turbulente Strömung
Grobstruktursimulation
PALM
Meteorlogie
Software
The Parallelized Large-Eddy Simulation Model (PALM) version 4.0 for atmospheric and oceanic flows: model formulation, recent developments, and future perspectives
oai:www.repo.uni-hannover.de:123456789/462022-12-02T16:10:15Zcom_123456789_1col_123456789_8ddc:550doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersionddc:570
00925njm 22002777a 4500
dc
Gentsch, Norman
author
Mikutta, Robert
author
Alves, Ricardo J. Eloy
author
Barta, Jin
author
Čapek, Petr
author
Gittel, Antje
author
Hugelius, Gustaf
author
Kuhry, Peter
author
Lashchinskiy, Nikolay
author
Palmtag, Juri
author
Richter, Andreas
author
Šantrůčková, Hana
author
Schnecker, Jörg
author
Shibistova, Olga
author
Urich, Tim
author
Wild, B.
author
Guggenberger, Georg
author
2015
In permafrost soils, the temperature regime and the resulting cryogenic processes are important determinants of the storage of organic carbon (OC) and its small-scale spatial variability. For cryoturbated soils, there is a lack of research assessing pedon-scale heterogeneity in OC stocks and the transformation of functionally different organic matter (OM) fractions, such as particulate and mineral-associated OM. Therefore, pedons of 28 Turbels were sampled in 5 m wide soil trenches across the Siberian Arctic to calculate OC and total nitrogen (TN) stocks based on digital profile mapping. Density fractionation of soil samples was performed to distinguish between particulate OM (light fraction, LF, < 1.6 g cm−3), mineral associated OM (heavy fraction, HF, > 1.6 g cm−3), and a mobilizable dissolved pool (mobilizable fraction, MoF). Across all investigated soil profiles, the total OC storage was 20.2 ± 8.0 kg m−2 (mean ± SD) to 100 cm soil depth. Fifty-four percent of this OC was located in the horizons of the active layer (annual summer thawing layer), showing evidence of cryoturbation, and another 35 % was present in the upper permafrost. The HF-OC dominated the overall OC stocks (55 %), followed by LF-OC (19 % in mineral and 13 % in organic horizons). During fractionation, approximately 13 % of the OC was released as MoF, which likely represents a readily bioavailable OM pool. Cryogenic activity in combination with cold and wet conditions was the principle mechanism through which large OC stocks were sequestered in the subsoil (16.4 ± 8.1 kg m−2; all mineral B, C, and permafrost horizons). Approximately 22 % of the subsoil OC stock can be attributed to LF material subducted by cryoturbation, whereas migration of soluble OM along freezing gradients appeared to be the principle source of the dominant HF (63 %) in the subsoil. Despite the unfavourable abiotic conditions, low C / N ratios and high δ13C values indicated substantial microbial OM transformation in the subsoil, but this was not reflected in altered LF and HF pool sizes. Partial least-squares regression analyses suggest that OC accumulates in the HF fraction due to co-precipitation with multivalent cations (Al, Fe) and association with poorly crystalline iron oxides and clay minerals. Our data show that, across all permafrost pedons, the mineral-associated OM represents the dominant OM fraction, suggesting that the HF-OC is the OM pool in permafrost soils on which changing soil conditions will have the largest impact.
Gentsch, N.; Mikutta, R.; Alves, R.J.E.; Barta, J.; Čapek, P.; Gittel, A. et al.: Storage and transformation of organic matter fractions in cryoturbated permafrost soils across the Siberian Arctic. In: Biogeosciences 12 (2015), S. 4525-4542. DOI: http://dx.doi.org/10.5194/bg-12-4525-2015
http://www.repo.uni-hannover.de/handle/123456789/46
http://dx.doi.org/10.15488/28
permafrost soils
organic carbon
carbon
siberian arctic
gelogy
biology
arctic
siberia
Geologie
Biologie
Permafrostboden
Kohlenstoff
organischer Kohlenstoff
Arktis
Sibirien
Storage and transformation of organic matter fractions in cryoturbated permafrost soils across the Siberian Arctic
oai:www.repo.uni-hannover.de:123456789/472022-12-02T16:17:36Zcom_123456789_1col_123456789_6doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersionddc:610
00925njm 22002777a 4500
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Kobler, Jan-Philipp
author
Dhanasingh, Anandhan
author
Kiran, Raphael
author
Jolly, Claude
author
Ortmaier, Tobias
author
2015
To develop skills sufficient for hearing preservation cochlear implant surgery, surgeons need to performseveral electrode insertion trials in ex vivo temporal bones, thereby consuming relatively expensive electrode carriers. The objectives of this study were to evaluate the insertion characteristics of cochlear electrodes in a plastic scala tympani model and to fabricate radio opaque polymer filament dummy electrodes of equivalent mechanical properties. In addition, this study should aid the design and development of new cochlear electrodes. Automated insertion force measurement is a new technique to reproducibly analyze and evaluate the insertion dynamics and mechanical characteristics of an electrode. Mechanical properties of MED-EL’s FLEX28, FLEX24, and FLEX20 electrodes were assessed with the help of an automated insertion tool. Statistical analysis of the overall mechanical behavior of the electrodes and factors influencing the insertion force are discussed. Radio opaque dummy electrodes of comparable characteristics were fabricated based on insertion force measurements. The platinum-iridium wires were replaced by polymer filament to provide sufficient stiffness to the electrodes and to eradicate the metallic artifacts in X-ray and computed tomography (CT) images. These low-cost dummy electrodes are cheap alternatives for surgical training and for in vitro, ex vivo, and in vivo research purposes.
Kobler, Jan-Philipp; Dhanasingh, Anandhan; Kiran, Raphael; Jolly, Claude; Ortmaier, Tobias: Cochlear Dummy Electrodes for Insertion Training and Research Purposes: Fabrication, Mechanical Characterization, and Experimental Validation. In: BioMed Research International 2015 (2015), Nr. 5. DOI: http://dx.doi.org/10.1155/2015/574209
http://www.repo.uni-hannover.de/handle/123456789/47
http://dx.doi.org/10.15488/29
Otolaryngology
Cochlear implant
surgery
cochlear implant surgery
cochlear electrodes
Electrodes
Cochlear Implantat
Hals-Nasen-Ohren-Heilkunde
Chirurgie
Elekroden
Cochlear Dummy Electrodes for Insertion Training and Research Purposes: Fabrication, Mechanical Characterization, and Experimental Validation
oai:www.repo.uni-hannover.de:123456789/482022-12-02T15:02:16Zcom_123456789_1col_123456789_2doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersionddc:710
00925njm 22002777a 4500
dc
Albert, Christian
author
Haaren, Christina von
author
Vargas-Moreno, Juan Carlos
author
Steinitz, Carl
author
2015-05-28
This paper investigates the contributions of an intensive educational workshop to advance students’ understanding and skills for collaborative, scenario-based landscape planning. The research design involves a case study workshop with thirty international students and several regional experts as well as a multi-stage, in-process evaluation. The workshop resulted in six different alternative futures for the region of Cagliari, Italy, and a seventh combined version that was considered best by regional reviewers. The students’ learning evaluation showed substantial advances in their relevant understanding and skills. Key aspects of the workshop pedagogy and the evaluation are discussed, and recommendations for future applications presented.
Albert, Christian; Haaren, Christina von; Vargas-Moreno, Juan; Steinitz, Carl: Teaching Scenario-Based Planning for Sustainable Landscape Development: An Evaluation of Learning Effects in the Cagliari Studio Workshop. In: Sustainability 7 (2015), Nr. 6, S. 6872-6892. DOI: http://dx.doi.org/10.3390/su7066872
http://www.repo.uni-hannover.de/handle/123456789/48
http://dx.doi.org/10.15488/30
sustainable landscape development
landscape planning
scenarios
education
evaluation
Cagliari
Italy
nachhaltige Landschaftsentwicklung
Landschaftsentwicklung
Nachhaltigkeit
Landschaftsplanung
Szenario
Bildung
Bewertung
Evaluation
Evaluierung
Cagliari
Italien
Teaching Scenario-Based Planning for Sustainable Landscape Development: An Evaluation of Learning Effects in the Cagliari Studio Workshop
oai:www.repo.uni-hannover.de:123456789/492022-12-02T15:15:01Zcom_123456789_1col_123456789_7doc-type:Articledoc-type:Textopen_accessddc:530status-type:publishedVersion
00925njm 22002777a 4500
dc
Schinke, Carsten
author
Peest, Peter Christian
author
Schmidt, Jan
author
Brendel, Rolf
author
Bothe, Karsten
author
Vogt, Malte R.
author
Kröger, Ingo
author
Winter, Stefan
author
Schirmacher, Alfred
author
Lim, Siew
author
Nguyen, Hieu T.
author
MacDonald, Daniel
author
2015
Metallic Zn nanodisks with hexagonal morphology were obtained onto glass substrate under vacuum thermal evaporation. A thermal characterization of Zn nanodiks showed a lower oxidation temperature than source powder Zn. Different thermal treatment on Zn nanodisks played an important role on the morphology, crystal size and surface vibrational modes of ZnO. The growth of ZnO nanoneedles started at the edge of metallic zinc hexagonal structures according with SEM images, the higher temperature the longer needles were grown. XRD diffractogram confirmed the wurtzite structure of ZnO with metallic nuclei. A wide band between 530 and 580 cm(-1) of Raman scattering corresponded at surface vibrational modes not observed at higher temperature.
Schinke, Carsten; Peest, Peter Christian; Schmidt, Jan; Brendel, Rolf; Bothe, Karsten; Vogt, Malte R. et al.: Uncertainty analysis for the coefficient of band-to-band absorption of crystalline silicon. In: AIP Advances 5 (2015), Nr. 6. DOI: http://dx.doi.org/10.1063/1.4923379
http://www.repo.uni-hannover.de/handle/123456789/49
http://dx.doi.org/10.15488/31
crystalline silicon
silicon
absorption coefficient
error analysis
solar cells
photoluminescence
Photovoltaic
kristallines Silizium
c-Si
Silizium
Absorptionskoeffizient
Fehleranalyse
Solarzelle
Photovoltaikzelle
Photolumineszenz
Fotolumineszenz
Photovoltaik
Uncertainty analysis for the coefficient of band-to-band absorption of crystalline silicon
oai:www.repo.uni-hannover.de:123456789/502022-12-02T15:02:16Zcom_123456789_1col_123456789_2doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersionddc:710
00925njm 22002777a 4500
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Krätzig, Sebastian
author
Warren-Kretzschmar, Bartlett
author
2014-01-02
Public involvement in the landscape planning process is an essential opportunity to communicate the goals and objectives of a sustainable planning. However, it is also important to accommodate citizen’s attitudes and perceptions of sustainability on a local or regional scale in the decision-making process. This involvement can be supported by interactive information, discussion, and learning opportunities. This article examines how communication in the context of environmental issues can be supported by modern web tools, social media, and new visualization approaches. Furthermore, the potential of social media to support communication about sustainability on a local scale and the prerequisites for its use in the planning process are discussed. Using a case study about citizens’ response to the development of intensive livestock farming in rural setting, we examine what the perception of sustainability on local scale could mean for citizens. Another case study about interactive landscape planning illustrates how such tools can promote communication about environmental issues and local sustainability. Using a framework for the use of social media, we suggest different application levels of social media in participatory planning. Finally, the opportunities to support sustainable decisions with landscape visualization in environmental planning and decision-making issues are discussed.
Krätzig, Sebastian; Warren-Kretzschmar, Bartlett: Using Interactive Web Tools in Environmental Planning to Improve Communication about Sustainable Development. In: Sustainability 6 (2014), Nr. 1, S. 236-250. DOI: http://dx.doi.org/10.3390/su6010236
http://www.repo.uni-hannover.de/handle/123456789/50
http://dx.doi.org/10.15488/32
internet
environmental planning
participatory planning
communication
web tools
social media
visualization
local sustainability
Internet
Umweltplanung
Kommunikation
Web-Tools
Social Media
Soziale Medien
Partizipative Planung
Visualisierung
Lokale Nachhaltigkeit
Nachaltigkeit
Region
Landschaftsgestaltung
Using Interactive Web Tools in Environmental Planning to Improve Communication about Sustainable Development
oai:www.repo.uni-hannover.de:123456789/512022-12-02T16:11:40Zcom_123456789_1col_123456789_8doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersionddc:580
00925njm 22002777a 4500
dc
Papenbrock, Jutta
author
Turcios, Ariel E.
author
2014-02-20
Many aquaculture systems generate high amounts of wastewater containing compounds such as suspended solids, total nitrogen and total phosphorus. Today, aquaculture is imperative because fish demand is increasing. However, the load of waste is directly proportional to the fish production. Therefore, it is necessary to develop more intensive fish culture with efficient systems for wastewater treatment. A number of physical, chemical and biological methods used in conventional wastewater treatment have been applied in aquaculture systems. Constructed wetlands technology is becoming more and more important in recirculating aquaculture systems (RAS) because wetlands have proven to be well-established and a cost-effective method for treating wastewater. This review gives an overview about possibilities to avoid the pollution of water resources; it focuses initially on the use of systems combining aquaculture and plants with a historical review of aquaculture and the treatment of its effluents. It discusses the present state, taking into account the load of pollutants in wastewater such as nitrates and phosphates, and finishes with recommendations to prevent or at least reduce the pollution of water resources in the future.
Turcios, Ariel E.; Papenbrock, Jutta: Sustainable Treatment of Aquaculture Effluents – What Can We Learn from the Past for the Future?. In: Sustainability 6 (2014), Nr. 2, S. 836-856. DOI: http://dx.doi.org/10.3390/su6020836
http://www.repo.uni-hannover.de/handle/123456789/51
http://dx.doi.org/10.15488/33
aquaculture
aquaponics
halophytes
nutrients
Salicornia spp.
wastewater
wetlands
Salicornia
Aquakultur
Aquaponik
Salzpflanze
Halophyt
Nährstoff
Salicornia
Salicornia spp.
Queller
Fuchsschwanzgewächs
Amaranthaceae
Abwasser
Feuchtgebiet
Sustainable Treatment of Aquaculture Effluents – What Can We Learn from the Past for the Future?
oai:www.repo.uni-hannover.de:123456789/522022-12-02T15:15:01Zcom_123456789_1col_123456789_7doc-type:Articledoc-type:Textopen_accessddc:530status-type:publishedVersion
00925njm 22002777a 4500
dc
Krieg, U.
author
Zhang, Yu
author
Tegenkamp, Christoph
author
Pfnür, Herbert
author
2014
We generated arrays of silver wires with a height of 1 atom and an average width of 11 atoms on the Si(557) surface via self-assembly with local √3 x √3 order, and investigated the 1D plasmon formation in them using a combination of high-resolution electron loss spectroscopy with low-energy electron diffraction. After a series of thermal desorption experiments followed by adding small concentrations of Ag, pure Ag-√3 ordered arrays of nanowires, separated by (113) facets, are intrinsically semi metallic or semiconducting, i.e., the metallicity of the Ag wires seems to be caused by excess atoms added to the (locally) perfectly ordered √3 x √3 layer. The proof has been carried out by post-adsorption of Ag atoms in the range between 0.004 to 0.03 monolayers and the quantitative determination of the frequency dependence of the 1D plasmon due to this excess Ag concentration. As expected for a doping mechanism, there is no minimum excess concentration. The lack of temperature dependence is not compatible with the formation of an adatom gas in the second layer, but suggests extrinsic doping by adatoms bound at the stepped (113) facets. Although strong deviations from a nearly free electron gas are expected in 1D, the Ag concentration dependence of the 1D plasmonic losses is fully compatible with the √ne dependence predicted by this model. Adsorption of traces of residual gas can have a qualitatively similar doping effect.
Krieg, U.; Zhang, Yu; Tegenkamp, C.; Pfnür, H.: Tuning of one-dimensional plasmons by Ag-Doping in Ag-√3-ordered atomic wires. In: New Journal of Physics 16 (2014), Nr. 4. DOI: http://dx.doi.org/10.1088/1367-2630/16/4/043007
http://www.repo.uni-hannover.de/handle/123456789/52
http://dx.doi.org/10.15488/34
one-dimensional plasmons
Ag monolayer
Si vicinal surface
doping
Si
Silicon
vicinal surface
plasmons in one dimension
Plasmon
eindimensionale Plasmonen
1D-Plasmonen
Monoschicht
Ag-Monoschicht
Silber
Ag
Si
Silicium
vicinale Oberfläche
Tuning of one-dimensional plasmons by Ag-Doping in Ag-√3-ordered atomic wires
oai:www.repo.uni-hannover.de:123456789/532022-12-02T15:02:17Zcom_123456789_1col_123456789_2doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersionddc:710
00925njm 22002777a 4500
dc
Boll, Thiemen
author
Haaren, Christina von
author
Ruschkowski, Eick von
author
2014-10-14
In the wake of urbanisation processes and the constitution of metropolitan regions, the role of the city's rural surroundings is receiving more attention from researchers and planners as rural areas offer various (cultural) ecosystem services for the urban population. Urban dwellers increasingly desire recreation and landscape experience. Although this need for recreation is generally recognized, few studies have focused on the question of people's preferences for certain types and characteristics of outdoor recreation areas in relation to the frequency of use. In order to acquire baseline data on this subject, the main objectives of this study were to explore recreation preferences of urban dwellers and the relation between actual use and perceived value of recreation areas in a case study in the Hamburg Metropolitan Region (Germany). In a social survey, Hamburg residents (n = 400) were asked about their preferences and use of four important regional recreation areas with different landscape characteristics in face-to-face interviews in different locations in the city. We found that both outdoor recreation within and outside of the city were fairly or very important for more than 70% of the questioned urban dwellers. Interestingly, the preference for a recreation area outside of the city did not depend on the frequency of use, which indicates that certain recreation areas had a symbolic value besides their use value. When people were questioned on the characteristics of recreation areas, perceived naturalness was found to be strongly related to preference. Respondents considered the diversity, uniqueness, and naturalness of the landscape to be far more important than the accessibility of the recreation areas and the provision of service facilities.
Boll, Thiemen; Haaren, Christina von; Ruschkowski, Eick von: The Preference and Actual Use of Different Types of Rural Recreation Areas by Urban Dwellers – The Hamburg Case Study. In: PLoS ONE 9 (2014), Nr. 10. DOI: http://dx.doi.org/10.1371/journal.pone.0108638
http://www.repo.uni-hannover.de/handle/123456789/53
http://dx.doi.org/10.15488/35
ecosystem services
landscape
perceptions
parks
recreation
age groups
urban ecology
rural areas
culture
attitudes
urban areas
survey
Hamburg
Stadtbevölkerung
Erholung
Landschaftserlebnis
Stadtökologie
Naturerlebnis
Erholungsgebiet
ländlicher Raum
ländliches Gebiet
Stadtgebiet
Natur
Naherholung
Befragung
Vorliebe
Studie
Hamburg
The Preference and Actual Use of Different Types of Rural Recreation Areas by Urban Dwellers – The Hamburg Case Study
oai:www.repo.uni-hannover.de:123456789/622022-12-02T16:16:27Zcom_123456789_1col_123456789_9doc-type:Articleddc:150ddc:796doc-type:Textopen_accessstatus-type:publishedVersion
00925njm 22002777a 4500
dc
Schmitz, Gerd
author
Bock, Otmar
author
2014-09-25
We compared sensorimotor adaptation in the visual and the auditory modality. Subjects pointed to visual targets while receiving direct spatial information about fingertip position in the visual modality, or they pointed to visual targets while receiving indirect information about fingertip position in the visual modality, or they pointed to auditory targets while receiving indirect information about fingertip position in the auditory modality. Feedback was laterally shifted to induce adaptation, and aftereffects were tested with both target modalities and both hands. We found that aftereffects of adaptation were smaller when tested with the non-adapted hand, i.e., intermanual transfer was incomplete. Furthermore, aftereffects were smaller when tested in the non-adapted target modality, i.e., intermodal transfer was incomplete. Aftereffects were smaller following adaptation with indirect rather than direct feedback, but they were not smaller following adaptation with auditory rather than visual targets. From this we conclude that the magnitude of adaptive recalibration rather depends on the method of feedback delivery (indirect versus direct) than on the modality of feedback (visual versus auditory).
Schmitz, Gerd; Bock, Otmar: A Comparison of Sensorimotor Adaptation in the Visual and in the Auditory Modality. In: PLoS ONE 9 (2014), Nr. 9. DOI: http://dx.doi.org/10.1371/journal.pone.0107834
http://www.repo.uni-hannover.de/handle/123456789/62
http://dx.doi.org/10.15488/44
hands
analysis of variance
vision
target detection
loudspeakers
chin
data acquisition
electromagnetics
sensitive period
Hand
Varianzanalyse
Vision
Zielerkennung
Lautsprecher
Kinn
Datenerfassung
Sensomotorik
Kognition
Auditive Wahrnehmung
Visuomotorik
A Comparison of Sensorimotor Adaptation in the Visual and in the Auditory Modality
oai:www.repo.uni-hannover.de:123456789/542022-12-02T16:16:27Zcom_123456789_1col_123456789_10doc-type:Articledoc-type:Textopen_accessddc:330status-type:publishedVersion
00925njm 22002777a 4500
dc
Damm, Kathrin
author
Prenzler, Anne
author
Zuchandke, Andy
author
2014-04-12
Background: The main challenge in the context of health care reforms and priority setting is the establishment and/or maintenance of fairness and standard of care. For the political process and interdisciplinary discussion, the subjective perception of the health care system might even be as important as potential objective criteria. Of special interest are the perceptions of academic disciplines, whose representatives act as decision makers in the health care sector. The aim of this study is to explore and compare the subjective perception of fairness and standard of care in the German health care system among students of medicine, law, economics, philosophy, and religion. Methods: Between October 2011 and January 2012, we asked freshmen and advanced students of the fields mentioned above to participate in a paper and pencil survey. Prior to this, we formulated hypotheses. The data were analysed by micro econometric regression techniques. Results: Data from 1,088 students were included in the study. Medical students, freshmen, and advanced students perceive the standard of care significantly as being better than non-medical students. Differences in the perception of fairness are not significant between the freshmen of the academic disciplines; however, they increase with the number of study terms. Besides the field of study, further variables such as gender and health status have a significant impact on perceptions. Conclusions: Our results show that there are differences in the perception of fairness and standard of care between academic disciplines, which might influence the interdisciplinary discussion on health care reforms and priority setting.
Damm, Kathrin; Prenzler, Anne; Zuchandke, Andy: Does the perception of fairness and standard of care in the health system depend on the field of study? Results of an empirical analysis. In: BMC Health Services Research 14 (2014). DOI: http://dx.doi.org/10.1186/1472-6963-14-166
http://www.repo.uni-hannover.de/handle/123456789/54
http://dx.doi.org/10.15488/36
Fairness
Standard of care
Health care
Perception
Field of study
Germany
Study
Fairness
Gerechtigkeit
Pflegestandard
Gesundheitswesen
Wahrnehmung
Wissenschaftsdisziplin
Forschungsbereich
Forschungsgebiet
Deutschland
Studie
Does the perception of fairness and standard of care in the health system depend on the field of study? Results of an empirical analysis
oai:www.repo.uni-hannover.de:123456789/552022-12-02T15:19:58Zcom_123456789_1col_123456789_8doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersionddc:580
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Kiirika, Leonard Muriithi
author
Schmitz, Udo
author
Colditz, Frank
author
2014-07-17
ROP-type GTPases of plants function as molecular switches within elementary signal transduction pathways such as the regulation of ROS synthesis via activation of NADPH oxidases (RBOH-respiratory burst oxidase homolog in plants). Previously, we reported that silencing of the Medicago truncatula GTPase MtROP9 led to reduced ROS production and suppressed induction of ROS-related enzymes in transgenic roots (MtROP9i) infected with pathogenic (Aphanomyces euteiches) and symbiotic microorganisms (Glomus intraradices, Sinorhizobium meliloti). While fungal infections were enhanced, S. meliloti infection was drastically impaired. In this study, we investigate the temporal proteome response of M. truncatula MtROP9i transgenic roots during the same microbial interactions under conditions of deprived potential to synthesize ROS. In comparison with control roots (Mtvector), we present a comprehensive proteomic analysis using sensitive MS protein identification. For four early infection time-points (1, 3, 5, 24 hpi), 733 spots were found to be different in abundance: 213 spots comprising 984 proteins (607 unique) were identified after S. meliloti infection, 230 spots comprising 796 proteins (580 unique) after G. intraradices infection, and 290 spots comprising 1240 proteins (828 unique) after A. euteiches infection. Data evaluation by GelMap in combination with a heatmap tool allowed recognition of key proteome changes during microbial interactions under conditions of hampered ROS synthesis. Overall, the number of induced proteins in MtROP9i was low as compared with controls, indicating a dual function of ROS in defense signaling as well as alternative response patterns activated during microbial infection. Qualitative analysis of induced proteins showed that enzymes linked to ROS production and scavenging were highly induced in control roots, while in MtROP9i the majority of proteins were involved in alternative defense pathways such as cell wall and protein degradation.
Kiirika, Leonard M.; Schmitz, Udo; Colditz, Frank: The alternative Medicago truncatula defense proteome of ROS - defective transgenic roots during early microbial infection. In: Frontiers in Plant Science 5 (2014). DOI: http://dx.doi.org/10.3389/fpls.2014.00341
http://www.repo.uni-hannover.de/handle/123456789/55
http://dx.doi.org/10.15488/37
Gene silencing
GTPase ROP9
Medicago truncatula
pathogenic interactions
ROS-reactive oxygen species
RNA interference
symbiotic interactions
suppression of ROS
Gen-Silencing
GTPase ROP9
Medicago truncatula
Schneckenklee
Interaktion
Wechselwirkung
pathogene Interaktion
Reaktive Sauerstoffspezies
ROS
RNA-Interferenz
Symbiotische Interaktion
Pathogen
Krankheitserreger
The alternative Medicago truncatula defense proteome of ROS - defective transgenic roots during early microbial infection
oai:www.repo.uni-hannover.de:123456789/562022-12-02T15:02:17Zcom_123456789_1col_123456789_3ddc:004ddc:550doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersionddc:600
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Nadarajah, Nandakumaran
author
Paffenholz, Jens-André
author
Teunissen, Peter J.G.
author
2014-07-17
Direct geo-referencing is an efficient methodology for the fast acquisition of 3D spatial data. It requires the fusion of spatial data acquisition sensors with navigation sensors, such as Global Navigation Satellite System (GNSS) receivers. In this contribution, we consider an integrated GNSS navigation system to provide estimates of the position and attitude (orientation) of a 3D laser scanner. The proposed multi-sensor system (MSS) consists of multiple GNSS antennas rigidly mounted on the frame of a rotating laser scanner and a reference GNSS station with known coordinates. Precise GNSS navigation requires the resolution of the carrier phase ambiguities. The proposed method uses the multivariate constrained integer least-squares (MC-LAMBDA) method for the estimation of rotating frame ambiguities and attitude angles. MC-LAMBDA makes use of the known antenna geometry to strengthen the underlying attitude model and, hence, to enhance the reliability of rotating frame ambiguity resolution and attitude determination. The reliable estimation of rotating frame ambiguities is consequently utilized to enhance the relative positioning of the rotating frame with respect to the reference station. This integrated (array-aided) method improves ambiguity resolution, as well as positioning accuracy between the rotating frame and the reference station. Numerical analyses of GNSS data from a real-data campaign confirm the improved performance of the proposed method over the existing method. In particular, the integrated method yields reliable ambiguity resolution and reduces position standard deviation by a factor of about 0.8, matching the theoretical gain of √3/4 for two antennas on the rotating frame and a single antenna at the reference station.
Nadarajah, Nandakumaran; Paffenholz, Jens-André; Teunissen, Peter J. G.: Integrated GNSS Attitude Determination and Positioning for Direct Geo-Referencing. In: Sensors 14 (2014), Nr. 7, S. 12715-12734. DOI: http://dx.doi.org/10.3390/s140712715
http://www.repo.uni-hannover.de/handle/123456789/56
http://dx.doi.org/10.15488/38
global navigation satellite system
GNSS
attitude determination
multivariate constrained integer least-squares
MC-LAMBDA
carrier phase ambiguity resolution
direct geo-referencing
laser scanner
Globales Navigationssatellitensystem
GNSS
Lagebestimmung
Kleinste-Quadrate-Methode
MC-LAMBDA
Träger-Phasen-Mehrdeutigkeitsauflösung
Trägerphasen-Mehrdeutigkeitsauflösung
Mehrdeutigkeitsauflösung
Trägerphase
Direkte Georeferenzierung
Laserscanner
Positionsbestimmung
Integrated GNSS Attitude Determination and Positioning for Direct Geo-Referencing
oai:www.repo.uni-hannover.de:123456789/572022-12-02T15:15:01Zcom_123456789_1col_123456789_7doc-type:Articledoc-type:Textopen_accessddc:530status-type:publishedVersion
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Weimer, Hendrik
author
2014-09-25
We study the quantum melting of quasi-one-dimensional lattice models in which the dominant energy scale is given by a repulsive dipolar interaction. By constructing an effective low-energy theory, we show that the melting of crystalline phases can occur into two distinct liquid phases having the same algebraic decay of density–density correlations but showing a different non-local correlation function expressing string order. We present possible experimental realizations using ultracold atoms and molecules, introducing an implementation based on resonantly driven Rydberg atoms that offers additional benefits compared to a weak admixture of the Rydberg state.
Weimer, Hendrik: String order in dipole-blockaded quantum liquids. In: New Journal of Physics 16 (2014), Nr. 9. DOI: http://dx.doi.org/10.1088/1367-2630/16/9/093040
http://www.repo.uni-hannover.de/handle/123456789/57
http://dx.doi.org/10.15488/39
quantum phase transition
dipolar interaction
Rydberg atoms
Quantenphasenübergang
dipolare Wechselwirkung
Rydberg-Atom
Rydberg-Zustand
String order in dipole-blockaded quantum liquids
oai:www.repo.uni-hannover.de:123456789/582022-12-02T15:04:50Zcom_123456789_1col_123456789_6doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersionddc:600ddc:500
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Gryshkov, Oleksandr
author
Pogozhykh, Denys
author
Hofmann, Nicola
author
Pogozhykh, Olena
author
Müller, Thomas
author
Glasmacher, Birgit
author
2014-09-26
Alginate cell-based therapy requires further development focused on clinical application. To assess engraftment, risk of mutations and therapeutic benefit studies should be performed in an appropriate non-human primate model, such as the common marmoset (Callithrix jacchus). In this work we encapsulated amnion derived multipotent stromal cells (MSCs) from Callithrix jacchus in defined size alginate beads using a high voltage technique. Our results indicate that i) alginate-cell mixing procedure and cell concentration do not affect the diameter of alginate beads, ii) encapsulation of high cell numbers (up to 10×106 cells/ml) can be performed in alginate beads utilizing high voltage and iii) high voltage (15–30 kV) does not alter the viability, proliferation and differentiation capacity of MSCs post-encapsulation compared with alginate encapsulated cells produced by the traditional air-flow method. The consistent results were obtained over the period of 7 days of encapsulated MSCs culture and after cryopreservation utilizing a slow cooling procedure (1 K/min). The results of this work show that high voltage encapsulation can further be maximized to develop cell-based therapies with alginate beads in a non-human primate model towards human application.
Gryshkov, Oleksandr; Pogozhykh, Denys; Hofmann, Nicola; Pogozhykh, Olena; Mueller, Thomas; Glasmacher, Birgit: Encapsulating Non-Human Primate Multipotent Stromal Cells in Alginate via High Voltage for Cell-Based Therapies and Cryopreservation. In: PLoS ONE 9 (2014), Nr. 9. DOI: http://dx.doi.org/10.1371/journal.pone.0107911
http://www.repo.uni-hannover.de/handle/123456789/58
http://dx.doi.org/10.15488/40
Cross-linking
Cryopreservation
Marmoset
Air flow
Cell staining
Amnion
Flow rate
Cell differentiation
Vernetzung
Kryokonservierung
Callithrix jacchus
Weißbüschelaffe
Marmosetten
Luftstrom
Zellfärbung
Amnion
Flussrate
Durchsatz
Encapsulating Non-Human Primate Multipotent Stromal Cells in Alginate via High Voltage for Cell-Based Therapies and Cryopreservation
oai:www.repo.uni-hannover.de:123456789/592022-12-02T16:11:41Zcom_123456789_1col_123456789_8doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersionddc:580
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Klie, Maik
author
Schie, Stephan
author
Linde, Marcus
author
Debener, Thomas
author
2014-09-23
Polyploidy is a widespread phenomenon among higher plants and a major factor shaping the structure and evolution of plant genomes. The important ornamental chrysanthemum (Chrysanthemum indicum hybrid) possesses a hexaploid genome with 54 chromosomes and was classified based on its evolutionary origin and cytological methods as an allopolyploid. However, it is questionable whether cytological methods are sufficient to determine the type of ploidy, and there are more informative methods available based on molecular marker analyses. Therefore, we collected segregation data for 406 dominant molecular marker alleles [327 amplified fragment length polymorphism (AFLPs), 65 single-strand conformation polymorphism (SSCPs) and 14 microsatellites (EST-SSRs)] in a biparental F1 population of 160 individuals. We analyzed these data for the characteristics that differ between allopolyploids and autopolyploids, including the segregation ratio of each marker, the ratio of single-dose (SD) to multi-dose (MD) markers, the ratio of SD markers in coupling to those in repulsion and the banding patterns of the SSRs. Whereas the analysis of the segregation ratio of each polymorphic marker indicated disomic (13 markers) as well as hexasomic (eight markers) inheritance, the ratio of SD markers in coupling to those in repulsion was 1:0, which is characteristic of autopolyploids. The observed ratio of SD to MD markers was 0.67:0.33 which is significantly different to the expected segregation for auto- and allohexaploids. Furthermore, the three EST-SSR alleles were inherited in all possible combinations and were not independent of each other, as expected for fixed heterozygosity in allopolyploids. Combining our results with published cytological data indicates that cultivated chrysanthemums should be classified as segmental allohexaploids.
Klie, Maik; Schie, Stephan; Linde, Marcus; Debener, Thomas: The type of ploidy of chrysanthemum is not black or white: a comparison of a molecular approach to published cytological methods. In: Frontiers in Plant Science 5 (2014). DOI: http://dx.doi.org/10.3389/fpls.2014.00479
http://www.repo.uni-hannover.de/handle/123456789/59
http://dx.doi.org/10.15488/41
Allopolyploidy
Autopolyploidy
Molecular marker
Polysomic inheritance
Single dose markers
Linkage in repulsion
Chrysanthemum indicum
Chrysanthemum
Allopolyploidie
Autopolyploidie
molekularer Marker
Vererbung
Einzeldosis
Marker
Genkopplung
Genetische Kopplung
Chrysantheme
The type of ploidy of chrysanthemum is not black or white: a comparison of a molecular approach to published cytological methods
oai:www.repo.uni-hannover.de:123456789/602022-12-02T15:02:17Zcom_123456789_1col_123456789_3ddc:550doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersion
00925njm 22002777a 4500
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Rahman, Mohammad
author
Rusteberg, Bernd
author
Uddin, Mohammad
author
Saada, Muath
author
Rabi, Ayman
author
Sauter, Martin
author
2014-12-08
For better planning of a managed aquifer recharge (MAR) project, the most promising strategies should analyze the environmental impact, socio-economic efficiency, and their contribution to the existing or future water resource conditions in the region. The challenge of such studies is to combine and quantify a wide range of criteria from the environment and society. This necessity leads to an integrated concept and analysis. This paper outlines an integrated approach considering environmental, health, social and economic aspects to support in the decision-making process to implement a managed aquifer recharge project as a potential response to water resource problems. In order to demonstrate the approach in detail, this paper analysed several water resources management strategies based on MAR implementation, by using treated wastewater in the Northern Gaza Strip and the potential impacts of the strategies on groundwater resources, agriculture, environment, health, economy and society. Based on the Palestinian water policy (Year 2005–2025) on wastewater reuse, three MAR strategies were developed in close cooperation with the local decision makers. The strategies were compared with a base line strategy referred to as the so-called “Do Nothing Approach”. The results of the study show that MAR project implementation with treated wastewater at a maximum rate, considered together with sustainable development of groundwater, is the best and most robust strategy amongst those analyzed. The analysis shows the defined MAR strategies contribute to water resources development and environmental protection or improvement including an existing eutrophic lake. The integrated approach used in this paper may be applicable not only to MAR project implementation but also to other water resources and environmental development projects.
Rahman, Mohammad; Rusteberg, Bernd; Uddin, Mohammad; Saada, Muath; Rabi, Ayman; Sauter, Martin: Impact Assessment and Multicriteria Decision Analysis of Alternative Managed Aquifer Recharge Strategies Based on Treated Wastewater in Northern Gaza. In: Water 6 (2014), Nr. 12, S. 3807-3827. DOI: http://dx.doi.org/10.3390/w6123807
http://www.repo.uni-hannover.de/handle/123456789/60
http://dx.doi.org/10.15488/42
managed aquifer recharge
impact assessment
wastewater reuse
decision support
multicriteria analysis
Northern Gaza
Grundwasseranreicherung
Folgenabschätzung
Abwasser
Wiederverwendung
Aufbereitung
Entscheidungshilfe
Mehrkriterienanalyse
Multikriterienanalyse
Nord-Gaza
Nordgaza
Impact Assessment and Multicriteria Decision Analysis of Alternative Managed Aquifer Recharge Strategies Based on Treated Wastewater in Northern Gaza
oai:www.repo.uni-hannover.de:123456789/612022-12-02T15:19:58Zcom_123456789_1col_123456789_8doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersionddc:580
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Kiirika, Leonard Muriithi
author
Behrens, Christof
author
Braun, Hans-Peter
author
Colditz, Frank
author
2013-04-15
Legumes (Fabaceae, Leguminosae) are unique in their ability to carry out an elaborate endosymbiotic nitrogen fixation process with rhizobia proteobacteria. The symbiotic nitrogen fixation enables the host plants to grow almost independently of any other nitrogen source. Establishment of symbiosis requires adaptations of the host cellular metabolism, here foremost of the energy metabolism mainly taking place in mitochondria. Since the early 1990s, the galegoid legume Medicago truncatula Gaertn. is a well-established model for studying legume biology, but little is known about the protein complement of mitochondria from this species. An initial characterization of the mitochondrial proteome of M. truncatula (Jemalong A17) was published recently. In the frame of this study, mitochondrial protein complexes were characterized using Two-dimensional (2D) Blue native (BN)/SDS-PAGE. From 139 detected spots, the “first hit” (=most abundant) proteins of 59 spots were identified by mass spectrometry. Here, we present a comprehensive analysis of the mitochondrial “complexome” (the “protein complex proteome”) of M. truncatula via 2D BN/SDS-PAGE in combination with highly sensitive MS protein identification. In total, 1,485 proteins were identified within 158 gel spots, representing 467 unique proteins. Data evaluation by the novel GelMap annotation tool allowed recognition of protein complexes of low abundance. Overall, at least 36 mitochondrial protein complexes were found. To our knowledge several of these complexes were described for the first time in Medicago. The data set is accessible under http://www.gelmap.de/medicago/. The mitochondrial protein complex proteomes of Arabidopsis available at http://www.gelmap.de/arabidopsis/ and Medicago are compared.
Kiirika, Leonard Muriithi; Behrens, Christof; Braun, Hans-Peter; Colditz, Frank: The mitochondrial complexome of Medicago truncatula. In: Frontiers in Plant Science 4 (2013), 84. DOI: http://dx.doi.org/10.3389/fpls.2013.00084
http://www.repo.uni-hannover.de/handle/123456789/61
http://dx.doi.org/10.15488/43
Medicago truncatula
Mitochondrial complexome
2D BN/SDS-PAGE
GelMap annotation tool
mitochondrial prohibitins
Medicago truncatula
Schneckenklee
Mitochondrien
Proteinkomplex
Proteom
2D BN/SDS-PAGE
GelMap
Werkzeug
Anmerkungen
Prohibitin
PHB
The mitochondrial complexome of Medicago truncatula
oai:www.repo.uni-hannover.de:123456789/632022-12-02T15:19:58Zcom_123456789_1col_123456789_8doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersionddc:580
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Bussell, John D.
author
Behrens, Christof
author
Ecke, Wiebke
author
Eubel, Holger
author
2013-04-24
The analytical depth of investigation of the peroxisomal proteome of the model plant Arabidopsis thaliana has not yet reached that of other major cellular organelles such as chloroplasts or mitochondria. This is primarily due to the difficulties associated with isolating and obtaining purified samples of peroxisomes from Arabidopsis. So far only a handful of research groups have been successful in obtaining such fractions. To make things worse, enriched peroxisome fractions frequently suffer from significant organellar contamination, lowering confidence in localization assignment of the identified proteins. As with other cellular compartments, identification of peroxisomal proteins forms the basis for investigations of the dynamics of the peroxisomal proteome. It is therefore not surprising that, in terms of functional analyses by proteomic means, peroxisomes are lagging considerably behind chloroplasts or mitochondria. Alternative strategies are needed to overcome the obstacle of hard-to-obtain organellar fractions. This will help to close the knowledge gap between peroxisomes and other organelles and provide a full picture of the physiological pathways shared between organelles. In this review, we briefly summarize the status quo and discuss some of the methodological alternatives to classic organelle proteomic approaches.
Bussell, John D.; Behrens, Christof; Ecke, Wiebke; Eubel, Holger: Arabidopsis peroxisome proteomics. In: Frontiers in Plant Science 4 (2013). DOI: http://dx.doi.org/10.3389/fpls.2013.00101
http://www.repo.uni-hannover.de/handle/123456789/63
http://dx.doi.org/10.15488/45
Peroxisome
Subcellular localization
Protein:protein interaction
Free-flow electrophoresis
Functional proteomics
Targeted quantitation of proteins
Arabidopsis thaliana
Arabidopsis thaliana
Peroxisomen
Subzelluläre Lokalisation
Protein-Protein-Wechselwirkung
Protein-Protein-Interaktion
Free-flow-Elektrophorese
Freifluss-Elektrophorese
Trägerfreie Elektrophorese
Funktionelle Proteomik
Proteinquantifizierung
Gezielte Proteinquantifizierung
Proteomanalyse
Arabidopsis peroxisome proteomics
oai:www.repo.uni-hannover.de:123456789/642022-12-02T16:10:14Zcom_123456789_1col_123456789_8doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersionddc:580
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Eubel, Holger
author
Braun, Hans-Peter
author
Millar, A. Harvey
author
2005
Intact protein complexes can be separated by apparent molecular mass using a standard polyacrylarnide gel electrophoresis system combining mild detergents and the dye Coornassie Blue. Referring to the blue coloured gel and the gentle method of solubilization yielding native and enzymatically active protein complexes, this technique has been named Blue-Native Polyacrylarnide Gel-Electrophoresis (BN-PAGE). BN-PAGE has become the method of choice for the investigation of the respiratory protein complexes of the electron transfer chains of a range of organisms, including bacteria, yeasts, animals and plants. It allows the separation in two dimensions of extremely hydrophobic protein sets for analysis and also provides information on their native interactions. In this review we discuss the capabilities of BN-PAGE in proteornics and the wider investigation of protein:protein interactions with a focus on its use and potential in plant science.
Eubel, Holger; Braun, Hans-Peter; Millar, A. Harvey: Blue-native PAGE in plants: a tool in analysis of protein-protein interactions. In: Plant Methods 1 (2005). DOI: http://dx.doi.org/10.1186/1746-4811-1-11
http://www.repo.uni-hannover.de/handle/123456789/64
http://dx.doi.org/10.15488/46
Blue native PAGE
Destabilization
Plant proteomics
Protein complex
Blue-native PAGE in plants: a tool in analysis of protein-protein interactions
oai:www.repo.uni-hannover.de:123456789/652022-12-02T16:11:40Zcom_123456789_1col_123456789_8doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersionddc:580
00925njm 22002777a 4500
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Senkler, Michael
author
Braun, Hans-Peter
author
2012
In classical proteome analyses, final experimental data are (a) images of 2D protein separations obtained by gel electrophoresis and (b) corresponding lists of proteins which were identified by mass spectrometry (MS). For data annotation, software tools were developed which allow the linking of protein identity data directly to 2D gels ("clickable gels"). GelMap is a new online software tool to annotate 2D protein maps. It allows (i) functional annotation of all identified proteins according to biological categories defined by the user, e.g., subcellular localization, metabolic pathway, or assignment to a protein complex and (ii) annotation of several proteins per analyzed protein "spot" according to MS primary data. Options to differentially display proteins of functional categories offer new opportunities for data evaluation. For instance, if used for the annotation of 2D Blue native/SDS gels, GelMap allows the identification of protein complexes of low abundance. A web portal has been established for presentation and evaluation of protein identity data related to 2D gels and is freely accessible at http://www.gelmap.de/.
Senkler, Michael; Braun, Hans-Peter: Functional annotation of 2D protein maps: the GelMap portal. In: Frontiers in Plant Science 3 (2012). DOI: http://dx.doi.org/10.3389/fpls.2012.00087
http://www.repo.uni-hannover.de/handle/123456789/65
http://dx.doi.org/10.15488/47
proteomics
two-dimensional gel electrophoresis
mass spectrometry
data annotation
data visualization
web portal
software
Functional annotation of 2D protein maps: the GelMap portal
oai:www.repo.uni-hannover.de:123456789/662022-12-02T16:10:14Zcom_123456789_1col_123456789_8doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersionddc:580
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Hildebrandt, Tatjana M.
author
Di Meo, Ivano
author
Zeviani, Massimo
author
Viscomi, Carlo
author
Braun, Hans-Peter
author
2013
Hydrogen sulfide is a physiologically relevant signalling molecule. However, circulating levels of this highly biologically active substance have to be maintained within tightly controlled limits in order to avoid toxic side effects. In patients suffering from EE (ethylmalonic encephalopathy), a block in sulfide oxidation at the level of the SDO (sulfur dioxygenase) ETHE1 leads to severe dysfunctions in microcirculation and cellular energy metabolism. We used an Ethe1-deficient mouse model to investigate the effect of increased sulfide and persulfide concentrations on liver, kidney, muscle and brain proteomes. Major disturbances in post-translational protein modifications indicate that the mitochondrial sulfide oxidation pathway could have a crucial function during sulfide signalling most probably via the regulation of cysteine S-modifications. Our results confirm the involvement of sulfide in redox regulation and cytoskeleton dynamics. In addition, they suggest that sulfide signalling specifically regulates mitochondrial catabolism of FAs (fatty acids) and BCAAs (branched-chain amino acids). These findings are particularly relevant in the context of EE since they may explain major symptoms of the disease.
Hildebrandt, Tatjana M.; Di Meo, Ivano; Zeviani, Massimo; Viscomi, Carlo; Braun, Hans-Peter: Proteome adaptations in Ethe1-deficient mice indicate a role in lipid catabolism and cytoskeleton organization via post-translational protein modifications. In: Bioscience Report 33 (2013), Nr. 4, S. 575-584. DOI: http://dx.doi.org/10.1042/BSR20130051
http://www.repo.uni-hannover.de/handle/123456789/66
http://dx.doi.org/10.15488/48
branched-chain amino acid oxidation
ethylmalonic encephalopathy
hydrogen sulfide
mitochondria
redox regulation
sulfur dioxygenase
Proteome adaptations in Ethe1-deficient mice indicate a role in lipid catabolism and cytoskeleton organization via post-translational protein modifications
oai:www.repo.uni-hannover.de:123456789/672022-12-02T19:19:55Zcom_123456789_15col_123456789_16ddc:000doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersionddc:380
00925njm 22002777a 4500
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Schneider, Irka
author
2012
Fahrkartenautomaten und Kunden – eine Geschichte voller Missverständnisse. Wie oft ist es Ihnen schon so ergangen, dass Sie an einem Automaten ein Ticket kaufen wollten und entweder gar nicht zum Ziel kamen oder nach langem Hin und Her immer noch nicht so recht sicher waren, das richtige Ticket erhalten zu haben. Genau das wollten wir ändern. Unser Ziel war es, Kunden das Gefühl zu vermitteln, vom Automaten verstanden zu werden, und nicht Verständnis für die Eigenheiten des Automaten aufbringen zu müssen. Der vorliegende Beitrag stellt am Beispiel der Entwicklung des Bediendialoges für die stationären Fahrkartenautomaten der Münchner Verkehrsgesellschaft (MVG) vor, wie eine nutzerzentrierte Entwicklung der Bedienabläufe an einem digitalen Kommunikationsinstrument wie einem Ticketautomaten funktionieren kann.
Schneider, Irka: Nutzerzentrierte Entwicklung des Bediendialoges für die Münchner Fahrkartenautomaten. In: i-com 11 (2012), Nr. 2, S. 55-58. DOI: http://dx.doi.org/10.1524/icom.2012.0027
http://www.repo.uni-hannover.de/handle/123456789/67
http://dx.doi.org/10.15488/49
Fahrkartenautomat
Bediendialog
nutzerzentrierte Entwicklung
Fokusgruppe
Nutzertests
Prototypenentwicklung
ticket machine
group interview
focus group
usability
prototyping
operating dialog
Nutzerzentrierte Entwicklung des Bediendialoges für die Münchner Fahrkartenautomaten
oai:www.repo.uni-hannover.de:123456789/682022-12-02T19:19:55Zcom_123456789_15col_123456789_16doc-type:Articlestatus-type:updatedVersiondoc-type:Textopen_accessddc:380ddc:600
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Schneider, Irka
author
2011
Obwohl die Automatisierung des Vertriebs im ÖPNV durch Automaten und Abonnementsysteme und moderne Vertriebswege (Handy- und Online-Tickets) für viele Kunden bequeme Formen des Ticketserwerbs darstellen, gibt es zahlreiche Kundengruppen, für die diese neuen Vertriebskanäle ein großes Nutzungshindernis sind. Im Beitrag werden Wege aufgezeigt, wie die sogenannten Gebrauchstauglichkeit (engl. Usability) systematisch verbessert werden kann und dadurch automatisierte Vertriebskanäle zu aktiven Vertriebswegen entwickelt werden können. Erfahrungen dazu lassen sich aus einem Bereich der Wirtschaft übertragen, in dem Usability der zentrale Erfolgsfaktor ist, dem Internet. Damit der Kaufprozess erfolgreich abgeschlossen wird, reicht es nicht, die Kunden auf die Seite zu locken und ihnen die angebotenen Produkte näher zu bringen. Abbruchraten werden systematisch erhoben und ausgewertet. Bei Onlineshops liegen die Abbruchraten zwischen 27 und 66 %. Im ÖPNV gibt es dazu kaum Untersuchungsmaterial.
Schneider, Irka; Probst, Gerhard: Von der Usability zur Ertragssteigerung. In: Nahverkehrspraxis (2011), Nr. 5, S. 30-31. ISSN: 0342-9849
http://www.repo.uni-hannover.de/handle/123456789/68
http://dx.doi.org/10.15488/50
Öffentlicher Personennahverkehr
Kundenorientierung
Vertrieb
Automatisierung
grafische Benutzeroberfläche
Bedienoberflächen
local public transport
customer focus
distribution
automation
graphical user interface
Von der Usability zur Ertragssteigerung
oai:www.repo.uni-hannover.de:123456789/692022-12-02T19:19:55Zcom_123456789_15col_123456789_16doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersionddc:020ddc:370
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May, Anne
author
Kannenberg, Susanne
author
2014-04
Die Hochschule ist ein Lernraum – dieser Satz ist für die meisten ein Allgemeinplatz. Dahinter verbirgt sich aber weit mehr – eine entwicklungsfähige Zukunftsaufgabe, bei der es um mehr als ein räumlich- infrastrukturelles Angebot für Studierende geht. Für einen vielseitigen, zukunftsfähigen Lernraum ist die Entgrenzung institutioneller Zuständigkeiten notwendige Voraussetzung. Diese Notwendigkeit ergibt sich sowohl für die Entwicklung und den Betrieb von räumlich-technischen Infrastrukturen als auch für die Weiterentwicklung von Beratungs- und Schulungsangeboten. Dienstleistungskooperation ist nötig für zukunftsorientierte Supportangebote und lernunterstützende Dienste, wie z. B. die Vermittlung von Informations- und Medienkompetenz. Ausgehend von oben skizziertem Lernraum-Verständnis und den von der DINI-AG Lernräume beschriebenen Lernraum-Dimensionen sollen Akteure, Services und Kooperationsaufgaben beispielhaft illustriert und Herausforderungen für eine strategische Hochschulentwicklung dargestellt werden.
Dislimitation and Teamwork – the Necessity of Cooperation in the Field of Learning Spaces Abstract: Learning space is a future task, which is far beyond spatial and infrastructural offers for students. Learning space shall facilitate students’ autonomous and self-organized learning and thereby enhance their literacies. Dealing with this task, is impossible without the teamwork of various stakeholders from faculties, service facilities and administration units. Establishing versatile and sustainable learning space requires the dislimitation of structurally determined responsibilities for the benefit of pragmatic, target group-oriented measures, including all stakeholders and stakeholder’s units. The contribution presents a holistic understanding of learning space. Based on the dimensions of learning spaces as defined by the DINI work-group “Lernräume”, the authors exemplary illustrate common tasks, stakeholders and achievements.
May, Anne; Kannenberg, Susanne: Entgrenzung und Zusammenarbeit – die Notwendigkeit von Kooperationen im Lernraum. In: ABI Technik 34 (2014), Nr. 1, S. 9-19. DOI: http://dx.doi.org/10.1515/abitech-2014-0003
http://www.repo.uni-hannover.de/handle/123456789/69
http://dx.doi.org/10.15488/51
Hochschulentwicklung
Lernraum
Kooperationen
Hochschulen
Bibliotheken
Lernräume
Entgrenzung und Zusammenarbeit – die Notwendigkeit von Kooperationen im Lernraum
oai:www.repo.uni-hannover.de:123456789/702022-12-02T15:15:01Zcom_123456789_1col_123456789_7doc-type:Articledoc-type:Textopen_accessddc:530status-type:publishedVersion
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Richter, Florian
author
Becker, Daniel
author
Bény, Cédric
author
Schulze, Torben A.
author
Ospelkaus, Silke
author
Osborne, Tobias J.
author
2015
We study the reaction kinetics of chemical processes occurring in the ultracold regime and systematically investigate their dynamics. Quantum entanglement is found to play a key role in driving an ultracold reaction towards a dynamical equilibrium. In case of multiple concurrent reactions Hamiltonian chaos dominates the phase space dynamics in the mean field approximation.
Richter, Florian; Becker, Daniel; Bény, Cédric; Schulze, Torben A.; Ospelkaus, Silke; Osborne, Tobias J.: Ultracold chemistry and its reaction kinetics. In: New Journal of Physics 17 (2015), Nr. 5. DOI: http://dx.doi.org/10.1088/1367-2630/17/5/055005
http://www.repo.uni-hannover.de/handle/123456789/70
http://dx.doi.org/10.15488/52
ultracold molecules
entanglement
nonlinear dynamics
ultracold gases
ultrakalte Moleküle
Nichtlineare Dynamik
ultrakalte Gase
ultrakaltes Gas
Ultracold chemistry and its reaction kinetics
oai:www.repo.uni-hannover.de:123456789/712022-12-02T15:02:17Zcom_123456789_1col_123456789_3ddc:550doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersionddc:710
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Mohammad-pajooh, Ehsan
author
Ab. Aziz, K.
author
2014-05-27
The review of past researches discussed that factors such as climate change and movement toward urbanization will result in more frequent and severe disasters in the near future (Yasuhara et al., 2011). Flash flood is the most common type of disaster that residents of Kuala Lumpur (KL) come across, thus in this study, it was desired to discover the factors affecting preparedness among residents of KL as well as assessing the variation of individual preparedness among residents. With the aid of SPSS analysis, the reliability of data, correlation and regression analysis between the investigated factors and disaster preparedness were obtained. According to this research it was found that level of preparedness of residents of KL is still below average; majority of social demographic indicators such as income, education, age, and property ownership showed significant contribution to the variation of disaster preparedness among the residents. For instance men were much more prepared in comparison to women; residents with high level of income and education had also significantly higher preparedness compared to those with low level of income and education. Race was the only factor that differs from the findings of previous studies; since race does not affect the preparedness.
Mohammad-pajooh, E.; Ab. Aziz, K.: Investigating factors for disaster preparedness among residents of Kuala Lumpur. In: Natural Hazards and Earth System Sciences Discussions 2 (2014), Nr. 5, S. 3683-3709. DOI: http://dx.doi.org/10.5194/nhessd-2-3683-2014
http://www.repo.uni-hannover.de/handle/123456789/71
http://dx.doi.org/10.15488/53
disaster
preparedness
disaster preparedness
resident
Kuala Lumpur
study
Katastrophe
Naturkastrophe
Katastrophenschutz
Vorkehrung
Vorbereitung
Schutzmaßnahme
Einwohner
Kuala Lumpur
Studie
Investigating factors for disaster preparedness among residents of Kuala Lumpur
oai:www.repo.uni-hannover.de:123456789/762022-12-02T16:16:26Zcom_123456789_1col_123456789_8doc-type:Articleddc:540doc-type:Textopen_accessstatus-type:publishedVersionddc:570
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Schax, Emilia
author
Neunaber, Janek
author
Stahl, Frank
author
Walter, Johanna-Gabriela
author
Scheper, Thomas
author
Eichner, Simone
author
Kirschning, Andreas
author
Zeilinger, Carsten
author
2014-12-22
In diseases such as cancer, Alzheimer’s disease or malaria, disease-related proteins take advantage of the heat shock protein (HSP) control system for their own activation or maturation. There is a quest to find inhibitors that specifically bind to the HSPs. Here, we report on a novel multiplexed assay system for inhibitor screening based on a protein microarray (MA) technique that was developed for routine applications with storable MAs. Purified HSPs are printed as full-length proteins on microarrays and used as a drug target for the screening of new inhibitors. Derivatives obtained by a combination of biological and chemical synthesis were tested as competitors of ATP with a suggested affinity for several HSP proteins which are hHSP from human, AtHSP83 (Arabidopsis thaliana) and HtpG from Helicobacter pylori. Some of these new derivatives exerted selectivity between human and bacterial heat shock proteins. Printed human HSP90 was used to test the binding of denatured proteins on the client binding site of human HSP90, since the full-length HSP maintains the capability to bind putative clients or cochaperones. Initial data revealed that the microarray application can be used to identify directly elevated heat-shock protein levels in cancer cell lysates. We suggest that microarray-based assaying of HSP levels can be used as a marker for determining stress levels.
Schax, Emilia; Neunaber, Janek; Stahl, Frank; Walter, Johanna-Gabriela; Scheper, Thomas; Eichner, Simone et al.: Multiplexed heat shock protein microarray as a screening platform for the selection of novel drug compounds. In: Biodiscovery 14 (2014), Nr. 1. DOI: http://dx.doi.org/10.7750/BioDiscovery.2014.14.1
http://www.repo.uni-hannover.de/handle/123456789/76
http://dx.doi.org/10.15488/58
heat shock protein
inhibitor
non benzoquinone geldanamycin
protein microarray
screening
Hitzeschockproteine
Inhibitor
Nicht-Benzochinon-Geldanamycin
Protein-Mikroarray
Protein-Chip
Screening
Multiplexed heat shock protein microarray as a screening platform for the selection of novel drug compounds
oai:www.repo.uni-hannover.de:123456789/722022-12-02T15:02:17Zcom_123456789_1col_123456789_3ddc:550doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersion
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Goseberg, Nils
author
2013-11-22
Experiments are presented that focus on the interaction of single sinusoidal long waves with beachfront development on the shore. A pump-driven methodology is applied to generate the tested waves in the wave flume. The approaching waves firstly propagate over a horizontal bottom, then climbing up a 1 in 40 beach slope. The experiments reported here are confined to the surf similarity parameter of the waves ranging from ξ =7.69–10.49. The maximum run-up of the tested waves under undisturbed conditions agrees well with analytical results of of Madsen and Schäffer (2010). Beachfront development is modelled with cubic concrete blocks (macro-roughness (MR) elements). The obstruction ratio, the number of element rows parallel to the shoreline as well as the way of arranging the MR elements influences the overall reduction of maximum run-up compared to the undisturbed run-up conditions. Staggered and aligned as well as rotated and non-rotated arrangements are tested. As a result, nomograms are finally compiled to depict the maximum run-up reduction over the surf similarity parameter. In addition, some guidance on practical application of the results to an example location is given.
Goseberg, N.: Reduction of maximum tsunami run-up due to the interaction with beachfront development – application of single sinusoidal waves. In: Natural Hazards and Earth System Science 13 (2013), Nr. 11, S. 2991-3010. DOI: http://dx.doi.org/10.5194/nhess-13-2991-2013
http://www.repo.uni-hannover.de/handle/123456789/72
http://dx.doi.org/10.15488/54
long waves
vertical wall
n-waves
forces
bores
tsunami
runup height
reduction
Tsunami
Welle
Anlaufhöhe
Reduktion
Reduction of maximum tsunami run-up due to the interaction with beachfront development – application of single sinusoidal waves
oai:www.repo.uni-hannover.de:123456789/732022-12-02T15:02:16Zcom_123456789_1col_123456789_2doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersionddc:720ddc:580
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Schröder, Roland
author
Prasse, Rüdiger
author
2013-08-12
Vast amounts of cultivars of native plants are annually introduced into the semi-natural range of their wild relatives for revegetation and restoration. As cultivars are often selected towards enhanced biomass production and might transfer these traits into wild relatives by hybridization, it is suggested that cultivars and the wild x cultivar hybrids are competitively superior to their wild relatives. The release of such varieties may therefore result in unintended changes in native vegetation. In this study we examined for two species frequently used in re-vegetation (Plantago lanceolata and Lotus corniculatus) whether cultivars and artificially generated intra-specific wild x cultivar hybrids may produce a higher vegetative and generative biomass than their wilds. For that purpose a competition experiment was conducted for two growing seasons in a common garden. Every plant type was growing (a.) alone, (b.) in pairwise combination with a similar plant type and (c.) in pairwise interaction with a different plant type. When competing with wilds cultivars of both species showed larger biomass production than their wilds in the first year only and hybrids showed larger biomass production than their wild relatives in both study years. As biomass production is an important factor determining fitness and competitive ability, we conclude that cultivars and hybrids are competitively superior their wild relatives. However, cultivars of both species experienced large fitness reductions (nearly complete mortality in L. corniculatus) due to local climatic conditions. We conclude that cultivars are good competitors only as long as they are not subjected to stressful environmental factors. As hybrids seemed to inherit both the ability to cope with the local climatic conditions from their wild parents as well as the enhanced competitive strength from their cultivars, we regard them as strong competitors and assume that they are able to outperform their wilds at least over the short-term.
Schröder, Roland; Prasse, Rüdiger: Do Cultivated Varieties of Native Plants Have the Ability to Outperform Their Wild Relatives? In: PLoS ONE 8 (2013), Nr. 8. DOI: http://dx.doi.org/10.1371/journal.pone.0071066
http://www.repo.uni-hannover.de/handle/123456789/73
http://dx.doi.org/10.15488/55
seeds
seasons
habitats
hybridization
invasive species
grasslands
leaves
death rates
asymmetric competition
population sources
lanceolata 1
restoration
grassland
grasses
establishment
hybridization
adaptation
strategies
Saatgut
Jahreszeiten
Lebensraum
Hybridisierung
Invasive Arten
Wiese
Grasland
Blätter
Sterberate
Do Cultivated Varieties of Native Plants Have the Ability to Outperform Their Wild Relatives?
oai:www.repo.uni-hannover.de:123456789/742022-12-02T16:10:14Zcom_123456789_1col_123456789_8doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersionddc:580ddc:570
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Lesker, Till
author
Maiss, Edgar
author
2013-10-09
Plant-infecting viruses of the genera Alpha- and Betacryptovirus within the family Partitiviridae cause no visible effects on their hosts and are only transmitted by cell division and through gametes. The bipartite dsRNA genome is encoding a RNA-dependent RNA polymerase (RdRp) and a coat protein (CP). Aside from sequence and structural analysis, the investigation of protein interactions is another step towards virus characterization. Therefore, ORFs of two type members White Clover Cryptic Virus 1 and 2 (WCCV-1 and WCCV-2), as well as the related viruses from Red Clover and Dill were introduced into a bimolecular fluorescence complementation assay. We showed CP-CP dimerization for all tested viruses with localization for alphacryptoviruses at the nuclear membrane and for betacryptoviruses close to cell walls within the cytoplasm. For CPs of WCCV-1 and WCCV-2, deletion mutants were created to determine internal interaction sites. Moreover, RdRp self-interaction was found for all viruses, whereas CP-RdRp interactions were only detectable for the alphacryptoviruses. An intra-genus test of CPs was successful in various virus combinations, whereas an inter-genus interaction of WCCV-1CP and WCCV-2CP was absent. This is the first report of in vivo protein interactions of members in the family Partitiviridae, indicating distinct features of the alpha- and betacryptoviruses.
Lesker, Till; Maiss, Edgar: In planta Protein Interactions of Three Alphacryptoviruses and Three Betacryptoviruses from White Clover, Red Clover and Dill by Bimolecular Fluorescence Complementation Analysis. In: Viruses 5 (2013), Nr. 10, S. 2512-2530. DOI: http://dx.doi.org/10.3390/v5102512
http://www.repo.uni-hannover.de/handle/123456789/74
http://dx.doi.org/10.15488/56
Partitiviridae
Alphacryptovirus
Betacryptovirus
protein interaction
Bimolecular fluorescence complementation
BiFC
White Clover
Red Clover
Dill
Partitiviridae
Alphacryptovirus
Betacryptovirus
Protein-Wechselwirkung
Bimolekulare Fluoreszenzkomplementation
BiFC
Trifolium repens
Trifolium pratense
Anethum graveolens
In planta Protein Interactions of Three Alphacryptoviruses and Three Betacryptoviruses from White Clover, Red Clover and Dill by Bimolecular Fluorescence Complementation Analysis
oai:www.repo.uni-hannover.de:123456789/752022-12-02T16:16:27Zcom_123456789_1col_123456789_10doc-type:Articledoc-type:Textopen_accessddc:330status-type:publishedVersionddc:610
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Frank, Martin
author
Prenzler, Anne
author
Eils, Roland
author
Schulenburg, Johann-Matthias Graf von der
author
2013-12-12
Recently the sequencing of the human genome has become a major biological and clinical research field. However, the public health impact of this new technology with focus on the financial effect is not yet to be foreseen. To provide an overview of the current health economic evidence for genome sequencing, we conducted a thorough systematic review of the literature from 17 databases. In addition, we conducted a hand search. Starting with 5 520 records we ultimately included five full-text publications and one internet source, all focused on cost calculations. The results were very heterogeneous and, therefore, difficult to compare. Furthermore, because the methodology of the publications was quite poor, the reliability and validity of the results were questionable. The real costs for the whole sequencing workflow, including data management and analysis, remain unknown. Overall, our review indicates that the current health economic evidence for genome sequencing is quite poor. Therefore, we listed aspects that needed to be considered when conducting health economic analyses of genome sequencing. Thereby, specifics regarding the overall aim, technology, population, indication, comparator, alternatives after sequencing, outcomes, probabilities, and costs with respect to genome sequencing are discussed. For further research, at the outset, a comprehensive cost calculation of genome sequencing is needed, because all further health economic studies rely on valid cost data. The results will serve as an input parameter for budget-impact analyses or cost-effectiveness analyses.
Martin; Prenzler, Anne; Eils, Roland; Schulenburg, J-Matthias von der: Genome sequencing: a systematic review of health economic evidence. In: Health Economics Review 3 (2013), Nr. 1. DOI: http://dx.doi.org/10.1186/2191-1991-3-29
http://www.repo.uni-hannover.de/handle/123456789/75
http://dx.doi.org/10.15488/57
Genome
Sequencing
Health economics
Cost analysis
Genomsequenzierung
Gesundheitsökonomie
Kostenanalyse
Genome sequencing: a systematic review of health economic evidence
oai:www.repo.uni-hannover.de:123456789/772022-12-02T16:11:41Zcom_123456789_1col_123456789_8doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersionddc:570
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Zeilinger, Carsten
author
2014
MjK2 was expressed in E. coli cells as a fusion protein containing N-or C-terminal an antibody binding site and a histidinehexamer. The C-terminal tagged fusion protein allows the expression and purification of an extra soluble RCK domain at p34 kDa, whereas this additional RCK domain was lost when the N-terminal tagged construct was used. Upon removal of the fusion peptide from the purified N-terminal tagged channel monomer, MjK2 occurred as a stable tetramer when incubated with synthetic lipid. The channel activity was studied after reconstitution into liposomes by single channel recording or by an optical assay with the potassium sensing dye, PBFI. First the channel function was improved by single channel recording. Single channel recording confirmed the pH dependence of the channel activity with single channel conductances of 42, 70, 85 and 202 pS and indicated that a functional K+ channel was formed. To study the function of the reconstituted MjK2 activity in an optical assay the potassium release was initiated when the external BaCl2 block was compensated by addition of EDTA. The release of potassium was mediated by reconstituted MjK2 at low pH or by the presence of internal calcium at high pH. MgCl2 had no or weak effect, whereas cAMP at low pH caused a complete loss of potassium during the preparation. Alignments studies revealed that MjK2 has different structural features in the channel pore and the RCK composition and therefore a different function can be expected. Amino acid sequence and structural alignments showed that a Ca2+ binding site and a typical nucleotide-binding site is not present in the RCK domain of MjK2 and therefore a different behavior could be expected. In addition a lysine reach linker region as found in human sperm K+ channels hslo1 and hslo3can play similar role in the gating behavior.
Zeilinger, Carsten: MJK2, a K+Channel from M. Jannaschii Mediates pH Dependent Potassium Transport Activity. In: Journal of Physical Chemistry & Biophysics 4 (2014), Nr. 5. DOI: dx.doi.org/10.4172/2161-0398.1000156
http://www.repo.uni-hannover.de/handle/123456789/77
http://dx.doi.org/10.15488/59
MjK2
K+ channel 2 of M. jannaschii
RCK
Regulator of Conductance of Potassium
Reconstitution
Single channel recording
PBFI
Benzofuranisophthalate dye
Methanococcus jannaschii
Methanocaldococcus jannaschii
MjK2
MJK2, a K+Channel from M. Jannaschii Mediates pH Dependent Potassium Transport Activity
oai:www.repo.uni-hannover.de:123456789/782022-12-02T16:10:14Zcom_123456789_1col_123456789_8doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersionddc:660
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Sambale, Franziska
author
Stahl, Frank
author
Rüdinger, Ferdinand
author
Seliktar, Dror
author
Kasper, Cornelia
author
Bahnemann, Detlef W.
author
Scheper, Thomas
author
2015
Nanoparticles have the potential to exhibit risks to human beings and to the environment; due to the wide applications of nanoproducts, extensive risk management must not be neglected. Therefore, we have constructed a cell-based, iterative screening system to examine a variety of nanoproducts concerning their toxicity during development. The sensitivity and application of various cell-based methods were discussed and proven by applying the screening to two different nanoparticles: zinc oxide and titanium dioxide nanoparticles. They were used as benchmarks to set up our methods and to examine their effects on mammalian cell lines. Different biological processes such as cell viability, gene expression of interleukin-8 and heat shock protein 70, as well as morphology changes were investigated. Within our screening system, both nanoparticle suspensions and coatings can be tested. Electric cell impedance measurements revealed to be a good method for online monitoring of cellular behavior. The implementation of three-dimensional cell culture is essential to better mimic in vivo conditions. In conclusion, our screening system is highly efficient, cost minimizing, and reduces the need for animal studies.
Sambale, Franziska; Stahl, Frank; Rüdinger, Ferdinand; Seliktar, Dror; Kasper, Cornelia; Bahnemann, Detlef; Scheper, Thomas: Iterative Cellular Screening System for Nanoparticle Safety Testing. In: Journal of Nanomaterials 2015 (2015). DOI: http://dx.doi.org/10.1155/2015/691069
http://www.repo.uni-hannover.de/handle/123456789/78
http://dx.doi.org/10.15488/60
titanium-dioxide nanoparticles
in-vitro
oxidative stress
zinc-oxide
epithelial-cells
toxicity
cytotoxicity
expression
culture
model
Titandioxid
Nanopartikel
Titandioxid Nanopartikel
In vitro
Oxidativer Stress
Zinkoxid
Epithelzelle
Toxizität
Zytotoxizität
Iterative Cellular Screening System for Nanoparticle Safety Testing
oai:www.repo.uni-hannover.de:123456789/792022-12-02T15:15:02Zcom_123456789_1col_123456789_7doc-type:Articledoc-type:Textopen_accessddc:530status-type:publishedVersion
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Langer, Thomas
author
Pfnür, Herbert
author
Tegenkamp, Christoph
author
Forti, Stiven
author
Emtsev, Konstantin
author
Starke, Ulrich
author
2012-10-29
We have investigated the plasmon dispersion in quasi-free-standing monolayer graphene (QFMLG) and epitaxial monolayer graphene (MLG) layers by means of angle resolved electron energy loss spectroscopy. We have shown that various intrinsic p-and n-doping levels in QFMLG and MLG, respectively, do not lead to different overall slopes of the sheet plasmon dispersion, contrary to theoretical predictions. Only the coupling of the plasmon to single particle interband transitions becomes obvious in the plasmon dispersion by characteristic points of inflections, which coincide with the location of the Fermi level above or below the Dirac point. Further evidence is given by thermal treatment of the QFML graphene layer with gradual desorption of intercalated hydrogen, which shifts the chemical potential toward the Dirac point. From a detailed analysis of the plasmon dispersion, we deduce that the interaction strength between the plasmon and the electron-hole pair excitation is increased by about 30% in QFMLG compared to MLG, which is attributed to a modified dielectric environment of the graphene film.
Langer, Thomas; Pfnür, Herbert; Tegenkamp, Christoph; Forti, Stiven; Emtsev, Konstantin; Starke, Ulrich: Manipulation of plasmon electron-hole coupling in quasi-free-standing epitaxial graphene layers. In: New Journal of Physics 14 (2012). DOI: http://dx.doi.org/10.1088/1367-2630/14/10/103045
http://www.repo.uni-hannover.de/handle/123456789/79
http://dx.doi.org/10.15488/61
Siliziumkarbid
Oberfläche
Gas
silicon-carbide
surfaces
gas
Manipulation of plasmon electron-hole coupling in quasi-free-standing epitaxial graphene layers
oai:www.repo.uni-hannover.de:123456789/802022-12-02T15:15:01Zcom_123456789_1col_123456789_7ddc:550doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersion
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Wuttke, Sigrid
author
Seckmeyer, Gunther
author
König-Langlo, Gert
author
2006-03-07
Spectral albedo in high resolution, from 290 to 1050 nm, has been measured at Neumayer, Antarctica, (70 390 S, 8 150 W) during the austral summer 2003/2004. At 500 nm, the spectral albedo nearly reaches unity, with slightly lower values below and above 500 nm. Above 600 nm, the spectral albedo decreases to values between 0.45 and 0.75 at 1000 nm. For one cloudless case an albedo up to 1.01 at 500 nm could be determined. This can be explained by the larger directional component of the snow reflectivity for direct incidence, combined with a slightly mislevelled sensor and the snow surface not being perfectly horizontal. A possible explanation for an observed decline in albedo is an increase in snow grain size. The theoretically predicted increase in albedo with increasing solar zenith angle (SZA) could not be observed. This is explained by the small range of SZA during albedo measurements, combined with the effect of changing snow conditions outweighing the effect of changing SZA. The measured spectral albedo serves as input for radiative transfer models, describing radiation conditions in Antarctica.
Wuttke, S.; Seckmeyer, G., König-Langlo, G.: Measurements of spectral snow albedo at Neumayer, Antarctica. In: Annales Geophysicae 24 (2006), Nr. 1, S. 7-21. DOI: http://dx.doi.org/10.5194/angeo-24-7-2006
http://www.repo.uni-hannover.de/handle/123456789/80
http://dx.doi.org/10.15488/62
polar meteorology
radiative process
atmospheric composition
atmospheric structure
transmission of radiation
scattering of radiation
meteorology
atmospheric dynamics
inhomogeneous surface albedo
radiative-transfer
uv irradiance
erythemal irradiance
davis station
sea-ice
ultraviolet
spectroradiometers
eflectance
model
Antarctica
Polarmeteorologie
Strahlungsprozess
Zusammensetzung
Struktur
Atmosphäre
Strahlungsübertragung
Strahlungsstreuung
Meteorologie
Atmosphärische Dynamik
Antarktis
Measurements of spectral snow albedo at Neumayer, Antarctica
oai:www.repo.uni-hannover.de:123456789/1772022-12-02T18:18:52Zcom_123456789_1col_123456789_8doc-type:Articleddc:540doc-type:Textopen_accessstatus-type:publishedVersion
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Cox, Russell J.
author
Szwalbe, Agnieszka J.
author
Williams, Katherine
author
O'Flynn, Daniel E.
author
Bailey, Andrew M.
author
Mulholland, Nicholas P.
author
Vincent, Jason L.
author
Willis, Christine L.
author
Simpson, Thomas J.
author
2015-10-02
The filamentous fungus Byssochlamys fulva strain IMI 40021 produces (+)-byssochlamic acid 1, its novel dihydroanalogue 2 and four related secondarymetabolites. Agnestadrides A, 17 and B, 18 constitute a novel class of seven-membered ring, maleic anhydride-containing (hence termed heptadride) natural products. The putative maleic anhydride precursor 5 for both nonadride and heptadride biosynthesis was isolated as a fermentation product for the first time and its structure confirmed by synthesis. Acid 5 undergoes facile decarboxylation to anhydride 6. The generic term maleidrides is proposed to encompass biosynthetically-related compounds containing maleic anhydride moieties fused to an alicyclic ring, varying in size and substituents.
Szwalbe, Agnieszka J.; Williams, Katherine; O'Flynn, Daniel E.; Bailey, Andrew M.; Mulholland, Nicholas P.; Vincent, Jason L.; Willis, Christine L.; Cox, Russell J.; Simpson, Thomas J.: Novel nonadride, heptadride and maleic acid metabolites from the byssochlamic acid producer Byssochlamys fulva IMI 40021 – an insight into the biosynthesis of maleidrides. In: Chemical Communications 51 (2015), Nr. 96, S. 17088-17091. DOI: http://dx.doi.org/10.1039/C5CC06988B
http://www.repo.uni-hannover.de/handle/123456789/177
http://dx.doi.org/10.15488/155
Byssochlamys fulva
Pilz
Byssochlamys fulva
Novel nonadride, heptadride and maleic acid metabolites from the byssochlamic acid producer Byssochlamys fulva IMI 40021 – an insight into the biosynthesis of maleidrides
oai:www.repo.uni-hannover.de:123456789/1752022-12-02T16:17:36Zcom_123456789_1col_123456789_9doc-type:WorkingPaperdoc-type:Textopen_accessstatus-type:publishedVersionddc:300
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Philipps, Axel
author
2007-12
Das Arbeitspapier beschäftigt sich mit den folgenden Fragen für ein ausgewähltes Stadtgebiet von Leipzig: Was kann man über die Schablonengraffiti erfahren, wenn man systematisch ein abgestecktes Stadtgebiet untersucht? Welche Motive und Themen sind zu finden? Welche Besonderheiten lassen sich beobachten? Der vorliegende Bericht präsentiert die Ergebnisse der ersten Felderhebung aus dem Jahr 2006.
Philipps, Axel: Schablonengraffitis im Stadtgebiet. Eine empirische Untersuchung der Inhalte und Verteilung. – Leipzig : Leipziger Forschungsgruppe Soziales, 2007. 13 S. (LFS-Arbeitsbericht ; 1). URL: http://www.forschungsgruppe-soziales.de/sites/default/files/LFSArbeitsbericht1.pdf
http://www.repo.uni-hannover.de/handle/123456789/175
http://dx.doi.org/10.15488/153
Graffiti
Street Art
Stencils
Street Reading
Leipzig
Graffiti
Street Art
Schablonengraffiti
Street Reading
Leipzig
Schablonengraffitis im Stadtgebiet. Eine empirische Untersuchung der Inhalte und Verteilung
oai:www.repo.uni-hannover.de:123456789/812022-12-02T16:11:40Zcom_123456789_1col_123456789_8doc-type:Articleddc:540doc-type:Textopen_accessstatus-type:publishedVersion
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Kirk, Ansgar T.
author
Allers, Maria
author
Cochems, Philipp
author
Langejuergen, Jens
author
Zimmermann, Stefan
author
2013
Drift tube ion mobility spectrometers (IMS) are widely used for fast trace gas detection in air, but portable compact systems are typically very limited in their resolving power. Decreasing the initial ion packet width improves the resolution, but is generally associated with a reduced signal-to-noise-ratio (SNR) due to the lower number of ions injected into the drift region. In this paper, we present a refined theory of IMS operation which employs a combined approach for the analysis of the ion drift and the subsequent amplification to predict both the resolution and the SNR of the measured ion current peak. This theoretical analysis shows that the SNR is not a function of the initial ion packet width, meaning that compact drift tube IMS with both very high resolution and extremely low limits of detection can be designed. Based on these implications, an optimized combination of a compact drift tube with a length of just 10 cm and a transimpedance amplifier has been constructed with a resolution of 183 measured for the positive reactant ion peak (RIP+), which is sufficient to e.g. separate the RIP+ from the protonated acetone monomer, even though their drift times only differ by a factor of 1.007. Furthermore, the limits of detection (LODs) for acetone are 180 ppt(v) within 1 s of averaging time and 580 pptv within only 100 ms.
Kirk, Ansgar T.; Allers, Maria; Cochems, Philipp; Langejuergen, Jens; Zimmermann, Stefan: A compact high resolution ion mobility spectrometer for fast trace gas analysis. In: Analyst 138 (2013), Nr. 18, S. 5200-5207. DOI: http://dx.doi.org/10.1039/C3AN00231D
http://www.repo.uni-hannover.de/handle/123456789/81
http://dx.doi.org/10.15488/63
Ion mobility spectrometry
high resolution
compact
isomers
isotopes
A compact high resolution ion mobility spectrometer for fast trace gas analysis
oai:www.repo.uni-hannover.de:123456789/822022-12-02T16:10:14Zcom_123456789_1col_123456789_8doc-type:Articleddc:540doc-type:Textopen_accessstatus-type:publishedVersion
00925njm 22002777a 4500
dc
Sallard, Sébastien
author
Schröder, Michael
author
Boissière, Cédric
author
Dunkel, Christian
author
Etienne, Mathieu
author
Walcarius, Alain
author
Oekermann, Torsten
author
Wark, Michael
author
Smarsly, Bernd M.
author
2013
In the present paper, we report the synthesis of bimodal mesoporous anatase TiO2 films by the EISA (Evaporation-Induced Self-Assembly) method using sol-gel chemistry combining two porogen agents, a low molecular weight ionic template and a neutral block copolymer. The surfactant template (C(16)mimCl) generates non-oriented worm-like pores (8 to 10 nm) which connect the regularly packed ellipsoidal mesopores (15 to 20 nm diameter) formed by an amphiphilic block copolymer of the type poly(isobutylene)-b-poly(ethylene oxide) (PIB-PEO). The surfactant template can also significantly influence the size and packing of the ellipsoidal mesopores. The mesostructural organization and mesoporosity of the films are studied by Environmental Ellipsometry-Porosimetry (EEP), Grazing-Incidence Small-Angle X-ray Scattering (GISAXS) and electron microscopy techniques. Electrochemical characterization is performed to study the permeability of the films to liquid solutions, using two types of probe moieties (K3FeIII(CN)(6) and Ru(bpy)(3)(2+)) by the wall-jet technique. An optimum ratio of C(16)mimCl/PIB-PEO provides anatase films with a continuous bimodal mesopore structure, possessing a permeability up to two times higher than that of the mesoporous films templated by PIB-PEO only (with partially isolated mesopores). When C(16)mimCl is used in large quantities, up to 20% weight vs. PIB-PEO, large overall porous volume and surface area are obtained, but the mesostructure is increasingly disrupted, leading to a severe loss of permeability of the bimodal films. A dye-sensitized solar cell set-up is used with anatase films as the photoelectrode. The photosensitizer loading and the total energy conversion efficiency of the solar cells using the mesoporous films templated by an optimal ratio of the two porogen agents C(16)mimCl and PIB-PEO can be substantially increased in comparison with the solar cells using mesoporous films templated by PIB-PEO only.
Sallard, Sébastien; Schröder, Michael; Boissière, Cédric; Dunkel, Christian; Etienne, Mathieu; Walcarius, Alain et al.: Bimodal mesoporous titanium dioxide anatase films templated by a block polymer and an ionic liquid: influence of the porosity on the permeability. In: Nanoscale 5 (2013), Nr. 24, S. 12316-12369. DOI: http://dx.doi.org/10.1039/C3NR02732E
http://www.repo.uni-hannover.de/handle/123456789/82
http://dx.doi.org/10.15488/64
sensitized solar-cells
silica thin-films
tio2 films
molecular-transport
lithium batteries
crystalline
generation
performance
architectures
accessibility
Bimodal mesoporous titanium dioxide anatase films templated by a block polymer and an ionic liquid: influence of the porosity on the permeability
oai:www.repo.uni-hannover.de:123456789/832022-12-02T15:19:58Zcom_123456789_1col_123456789_8doc-type:Articleddc:540doc-type:Textopen_accessstatus-type:publishedVersion
00925njm 22002777a 4500
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Schmidt, Moritz
author
Heck, Stephanie
author
Bosbach, Dirk
author
Ganschow, Steffen
author
Walther, Clemens
author
Stumpf, Thorsten
author
2013
We present a comprehensive study of the solid solution system Ca-2(MoO4)(2)-NaGd(MoO4)(2) on the molecular scale, by means of site-selective time resolved laser fluorescence spectroscopy (TRLFS). Eu3+ is used as a trace fluorescent probe, homogeneously substituting for Gd3+ in the solid solution crystal structure. Site-selective TRLFS of a series of polycrystalline samples covering the whole composition range of the solid solution series from 10% substitution of Ca2+ to the NaGd end-member reveals it to be homogeneous throughout the whole range. The trivalent ions are incorporated into the powellite structure in only one coordination environment, which exhibits a very strong ligand-metal interaction. Polarization-dependent measurements of a single crystal of NaGd(Eu)(MoO4)(2) identify the coordination geometry to be of C-2v point symmetry. The S-4 symmetry of the Ca site within the powellite lattice can be transformed into C-2v assuming minor motion in the first coordination sphere.
Schmidt, Moritz; Heck, Stephanie; Bosbach, Dirk; Ganschow, Steffen; Walther, Clemens; Stumpf, Thorsten: Characterization of powellite-based solid solutions by site-selective time resolved laser fluorescence spectroscopy. In: Dalton Transactions 42 (2013), Nr. 23, S. 8387-8393. DOI: http://dx.doi.org/10.1039/C3DT50146A
http://www.repo.uni-hannover.de/handle/123456789/83
http://dx.doi.org/10.15488/65
europium(III) luminescence
transition frequency
complexes
glass
lanthanide
eu(iii)
system
chemistry
ceramics
number
Characterization of powellite-based solid solutions by site-selective time resolved laser fluorescence spectroscopy
oai:www.repo.uni-hannover.de:123456789/852022-12-02T19:24:35Zcom_123456789_15col_123456789_16doc-type:BookPartddc:830doc-type:Textopen_accessstatus-type:publishedVersion
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Tempel, Bernhard
author
2014
Der Beitrag bietet eine selektive Skizze von Georg Lukács' Kritik an Gerhart Hauptmann zwischen 1903 und 1946. Schwerpunkte sind 1) Lukács’ Kritik des Naturalismus, wie er sie darlegt in seiner 'Entwicklungsgeschichte des modernen Dramas' im Kontext der "Suche nach dem großen Drama", das heißt der Tragödie, 2) Lukács' Urteile über Hauptmann, in denen er aus der Perspektive marxistischer Literaturkritik Sprach- und Denkbilder des Tragischen und der Tragödie auf die Persönlichkeit des Dichters überträgt.
Tempel, Bernhard: Passive und naive Helden. Georg Lukács als Kritiker der Tragödie Gerhart Hauptmanns. In: Lörke, Tim (Hrsg.): Von den Rändern zur Moderne : Studien zur deutschsprachigen Literatur zwischen Jahrhundertwende und Zweitem Weltkrieg ; Festschrift für Peter Sprengel zum 65. Geburtstag. Würzburg : Königshausen & Neumann, 2014, S. 127-146. ISBN: 978-3-8260-5484-6
http://www.repo.uni-hannover.de/handle/123456789/85
http://dx.doi.org/10.15488/67
Hauptmann, Gerhart
Rezeption
Lukács, Georg
Literatursoziologie
Passive und naive Helden. Georg Lukács als Kritiker der Tragödie Gerhart Hauptmanns
oai:www.repo.uni-hannover.de:123456789/842022-12-13T15:12:26Zcom_123456789_1col_123456789_9ddc:360doc-type:BookPartdoc-type:Textopen_accessstatus-type:publishedVersionddc:320ddc:300
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Philipps, Axel
author
2005
Der Beitrag untersucht das Protestmaterial von sechs Leipziger Montagsdemonstrationen zwischen dem 30. August und dem 4. Oktober 2004. Das Material wurde inhaltlich als auch hinsichtlich der Gestaltung analysiert und interpretiert.
Philipps, Axel: Weg mit Hartz IV! : Die Montagsdemonstrationen in Leipzig zwischen 30. August und 4. Oktober 2004. In: Gissendanner, Scott (Hrsg.): Partei braucht Gewerkschaft braucht Partei?. Berlin : Gesellschaft für sozialwissenschaftliche Forschung und Publizistik, 2005 (Berliner Debatte Initial ; 16,5). S. 93-104. ISBN: 3-936382-42-5. DOI: http://dx.doi.org/10.15488/66
http://www.repo.uni-hannover.de/handle/123456789/84
http://dx.doi.org/10.15488/66
Protest
Picture interpretation
documentary method
hermeneutic interpretation
East Germany
Protest
dokumentarische Methode
Montagsdemonstration
Ostdeutschland
rekonstruktive Bildinterpretation
Weg mit Hartz IV! : Die Montagsdemonstrationen in Leipzig zwischen 30. August und 4. Oktober 2004
oai:www.repo.uni-hannover.de:123456789/862022-12-02T15:19:58Zcom_123456789_1col_123456789_8doc-type:Articleddc:540doc-type:Textopen_accessstatus-type:publishedVersion
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Aguirre, Matias E.
author
Perelstein, Gonzalo
author
Feldhoff, Armin
author
Condo, Adriana
author
Tolley, Alfredo J.
author
Grela, Maria A.
author
2015
The room temperature spontaneous reduction of HAuCl4 in ethylene glycol in the presence of pre-formed ZnO nanoparticles is investigated by UV-vis spectroscopy. Analysis by HRTEM demonstrated that the synthesized nanostructures consist of small ZnO nanoparticles (5.0 nm) in contact with bigger (15 nm) spherical Au nanoparticles. The electronic communication between Au and ZnO blocks is confirmed by UV excitation of the colloid. These experiments indicate that ZnO nanoparticles efficiently transfer the electrons to Au nanoparticles in contact, inducing a 15 nm blue shift in the plasmon band. Titration experiments using the methylviologen couple (MV2+/MV center dot+) are presented and analyzed to quantify the enhancement in the electron storage capability in the new nanostructure and the negative shift in the Fermi level caused by the Au loading in ZnO.
Aguirre, Matias E.; Perelstein, Gonzalo; Feldhoff, Armin; Condo, Adriana; Tolley, Alfredo J.; Grela, Maria A. (2015): The spontaneous room temperature reduction of HAuCl4 in ethylene glycol in the presence of ZnO: a simple strategy to obtain stable Au/ZnO nanostructures exhibiting strong surface plasmon resonance and efficient electron storage properties. In: New Journal of Chemistry 39 (2015), Nr. 2, S. 909-914. DOI: http://dx.doi.org/10.1039/c4nj01663g
http://www.repo.uni-hannover.de/handle/123456789/86
http://dx.doi.org/10.15488/68
fermi-level equilibration
gold nanoparticles
polyol process
metal particles
quantum dots
nanocrystals
tio2
nanocomposites
mechanism
shape
The spontaneous room temperature reduction of HAuCl4 in ethylene glycol in the presence of ZnO: a simple strategy to obtain stable Au/ZnO nanostructures exhibiting strong surface plasmon resonance and efficient electron storage properties
oai:www.repo.uni-hannover.de:123456789/872022-12-02T15:19:58Zcom_123456789_1col_123456789_8doc-type:Articleddc:540doc-type:Textopen_accessstatus-type:publishedVersion
00925njm 22002777a 4500
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Tits, Jan
author
Walther, Clemens
author
Stumpf, Thorsten
author
Mace, Nathalie
author
Wieland, Erich
author
2015
Non-selective luminescence spectroscopy and luminescence line-narrowing spectroscopy were used to study the retention of UO22+ on titanium dioxide (TiO2), synthetic calcium silicate hydrate (C-S-H) phases and hardened cement paste (HCP). Non-selective luminescence spectra showed strong inhomogeneous line broadening resulting from a strongly disordered UO22+ bonding environment. This problem was largely overcome by using luminescence line-narrowing spectroscopy. This technique allowed unambiguous identification of three different types of UO22+ sorbed species on C-S-H phases and HCP. Comparison with spectra of UO22+ sorbed onto TiO2 further allowed these species to be assigned to a surface complex, an incorporated species and an uranate-like surface precipitate. This information provides the basis for mechanistic models describing the UO22+ sorption onto C-S-H phases and HCP and the assessment of the mobility of this radionuclide in a deep geological repository for low and intermediate level radioactive waste (L/ILW) as this kind of waste is often solidified with cement prior to storage.
Tits, Jan; Walther, Clemens; Stumpf, Thorsten; Mace, Nathalie; Wieland, Erich: A luminescence line-narrowing spectroscopic study of the uranium(VI) interaction with cementitious materials and titanium dioxide. In: Dalton Transactions 44 (2015), Nr. 3, S. 966-976. DOI: http://dx.doi.org/10.1039/c4dt02172j
http://www.repo.uni-hannover.de/handle/123456789/87
http://dx.doi.org/10.15488/69
laser fluorescence spectroscopy
silicate hydrate phases
uranyl ions
electronic-structure
actinyl ions
u(vi)
sorption
solubility
speciation
complexes
A luminescence line-narrowing spectroscopic study of the uranium(VI) interaction with cementitious materials and titanium dioxide
oai:www.repo.uni-hannover.de:123456789/882022-12-02T16:10:16Zcom_123456789_1col_123456789_8doc-type:Articleddc:540doc-type:Textopen_accessstatus-type:publishedVersion
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Hothorn, Ludwig A.
author
2014
The basic conclusions in almost all reports on new drug applications and in all publications in toxicology are based on statistical methods. However, serious contradictions exist in practice: designs with small samples sizes but use of asymptotic methods (i.e. constructed for larger sample sizes), statistically significant findings without biological relevance (and vice versa), proof of hazard vs. proof of safety, testing (e.g. no observed effect level) vs. estimation (e.g. benchmark dose), available statistical theory vs. related user-friendly software. In this review the biostatistical developments since about the year 2000 onwards are discussed, mainly structured for repeated-dose studies, mutagenicity, carcinogenicity, reproductive and ecotoxicological assays. A critical discussion is included on the unnecessarily conservative evaluation proposed in guidelines, the inadequate but almost always used proof of hazard approach, and the limitation of data-dependent decision-tree approaches.
Hothorn, Ludwig A.: Statistical evaluation of toxicological bioassays - a review. In: Toxicology Research 3 (2014), Nr. 6, S. 418-432. DOI: http://dx.doi.org/10.1039/c4tx00047a
http://www.repo.uni-hannover.de/handle/123456789/88
http://dx.doi.org/10.15488/70
simultaneous confidence-intervals
exchangeable binary data
historical control data
tumor-incidence rates
benchmark dose estimation
quantal-response test
subunit-specific outcomes
sprague-dawley rats
lymph-node assay
poly-k test
Statistical evaluation of toxicological bioassays - a review
oai:www.repo.uni-hannover.de:123456789/892022-12-02T16:10:16Zcom_123456789_1col_123456789_8doc-type:Articleddc:540doc-type:Textopen_accessstatus-type:publishedVersion
00925njm 22002777a 4500
dc
Sepelak, V.
author
Myndyk, Maxym
author
Witte, R.
author
Roeder, J.
author
Menzel, Dirk
author
Schuster, R.H.
author
Hahn, H.
author
Heitjans, Paul
author
Becker, Klaus-Dieter
author
2014
The response of the structure of the M-type barium hexaferrite (BaFe12O19) to mechanical action through high-energy milling and its impact on the magnetic behaviour of the ferrite are investigated. Due to the ability of the Fe-57 Mossbauer spectroscopic technique to probe the environment of the Fe nuclei, a valuable insight on a local atomic scale into the mechanically induced changes in the hexagonal structure of the material is obtained. It is revealed that the milling of BaFe12O19 results in the deformation of its constituent polyhedra (FeO6 octahedra, FeO4 tetrahedra and FeO5 triangular bi-pyramids) as well as in the mechanically triggered transition of the Fe3+ cations from the regular 12k octahedral sites into the interstitial positions provided by the magnetoplumbite structure. The response of the hexaferrite to the mechanical treatment is found to be accompanied by the formation of a non-uniform nanostructure consisting of an ordered crystallite surrounded/separated by a structurally disordered surface shell/interface region. The distorted polyhedra and the non-equilibrium cation distribution are found to be confined to the amorphous near-surface layers of the ferrite nanoparticles with the thickness extending up to about 2 nm. The information on the mechanically induced short-range structural disorder in BaFe12O19 is complemented by an investigation of its magnetic behaviour on a macroscopic scale. It is demonstrated that the milled ferrite nanoparticles exhibit a pure superparamagnetism at room temperature. As a consequence of the far-from-equilibrium structural disorder in the surface shell of the nanoparticles, the mechanically treated BaFe12O19 exhibits a reduced magnetization and an enhanced coercivity.
Sepelak, V.; Myndyk, M.; Witte, R.; Roeder, J.; Menzel, D.; Schuster, R. H. et al.: The mechanically induced structural disorder in barium hexaferrite, BaFe12O19, and its impact on magnetism. In: Faraday Discussions 170 (2014), S. 121-135. DOI: http://dx.doi.org/10.1039/c3fd00137g
http://www.repo.uni-hannover.de/handle/123456789/89
http://dx.doi.org/10.15488/71
nonequilibrium cation distribution
step mechanochemical route
canted spin arrangement
nickel ferrite
enhanced magnetization
mossbauer-spectroscopy
mechanosynthesis
nanoparticles
redistribution
surface
The mechanically induced structural disorder in barium hexaferrite, BaFe12O19, and its impact on magnetism
oai:www.repo.uni-hannover.de:123456789/902022-12-02T16:11:40Zcom_123456789_1col_123456789_8doc-type:Articleddc:540doc-type:Textopen_accessstatus-type:publishedVersion
00925njm 22002777a 4500
dc
Zahn, Gesa
author
Zerner, Philip
author
Lippke, Jann
author
Kempf, Fabian L.
author
Lilienthal, Sebastian
author
Schroeder, Christian A.
author
Schneider, Andreas M.
author
Behrens, Peter
author
2014
In this work, the formation of a Zr-based metal-organic framework (MOF), Zr-fumarate MOF (Zr-fum MOF), is studied in situ by energy-dispersive diffraction. The Zr-fum MOF can be synthesised in DMF as well as in water-based synthesis systems. In both cases, its formation requires modulation, i.e. a monocarboxylic acid which is used as the modulator has to be added to the synthesis mixture. In general, different mechanisms of modulation are possible, for example, deprotonation of the linker molecule (deprotonation modulation) or coordination modulation (wherein the molecules of the modulator compete with the linker molecules for the coordination sites at the inorganic building units). Independently of the specific mechanism, modulation often improves the reproducibility of the MOF synthesis and the crystallinity of the product and may be used to control crystal size and morphology. This study is the first to investigate the kinetics of modulated MOF syntheses with regard to coordination modulation. According to this concept, the addition of a modulator usually decelerates the reaction. Our kinetic investigations show that this is the case for the formation of Zr-fum MOF in the water-based synthesis with formic acid used as a modulator. On the contrary, the addition of formic acid to the DMF-based synthesis results in an accelerating effect. This unexpected effect can be attributed to a small amount of water present in formic acid. Correspondingly, the addition of water to the synthesis mixture also showed an accelerating effect. These investigations emphasise the subtle interplay of the different ingredients in a MOF synthesis. In the case of the Zr-fum MOF, both the modulator formic acid and the water content strongly affect the kinetics of crystallisation. Quantitative evaluation of the kinetic data using the Gualtieri equation provides additional insight into the mechanisms of coordination-modulated MOF formation reactions and excludes the idea of deprotonation modulation.
Zahn, Gesa; Zerner, Philip; Lippke, Jann; Kempf, Fabian L.; Lilienthal, Sebastian; Schroeder, Christian A. et al.: Insight into the mechanism of modulated syntheses: in situ synchrotron diffraction studies on the formation of Zr-fumarate MOF. In: CrystEngcomm 16 (2014), Nr. 39, S. 9198-9207. DOI: http://dx.doi.org/10.1039/c4ce01095g
http://www.repo.uni-hannover.de/handle/123456789/90
http://dx.doi.org/10.15488/72
metal-organic frameworks
x-ray-diffraction
phase-change
crystallization
kinetics
growth
Insight into the mechanism of modulated syntheses: in situ synchrotron diffraction studies on the formation of Zr-fumarate MOF
oai:www.repo.uni-hannover.de:123456789/912022-12-02T16:10:16Zcom_123456789_1col_123456789_8doc-type:Articleddc:540doc-type:Textopen_accessstatus-type:publishedVersion
00925njm 22002777a 4500
dc
Krivec, M.
author
Dillert, Ralf
author
Bahnemann, Detlef W.
author
Mehle, A.
author
Strancar, J.
author
Drazic, G.
author
2014
Photocatalytic degradation of dichloroacetic acid (DCA) was studied in a continuous-flow set-up using a titanium microreactor with an immobilized double-layered TiO2 nanoparticle/nanotube film. Chloride ions, formed during the degradation process, negatively affect the photocatalytic efficiency and at a certain concentration (approximately 0.5 mM) completely stop the reaction in the microreactor. Two proposed mechanisms of inhibition with chloride ions, competitive adsorption and photogenerated-hole scavenging, have been proposed and investigated by adsorption isotherms and electron paramagnetic resonance (EPR) measurements. The results show that chloride ions block the DCA adsorption sites on the titania surface and reduce the amount of adsorbed DCA molecules. The scavenging effect of chloride ions during photocatalysis through the formation of chlorine radicals was not detected.
Krivec, M.; Dillert, R.; Bahnemann, D. W.; Mehle, A.; Strancar, J.; Drazic, G.: The nature of chlorine-inhibition of photocatalytic degradation of dichloroacetic acid in a TiO2-based microreactor. In: Physical Chemistry Chemical Physics 16 (2014), Nr. 28, S. 14867-14873. DOI: http://dx.doi.org/10.1039/c4cp01043d
http://www.repo.uni-hannover.de/handle/123456789/91
http://dx.doi.org/10.15488/73
rate enhancement
inorganic-ions
tio2
oxidation
radicals
reactor
The nature of chlorine-inhibition of photocatalytic degradation of dichloroacetic acid in a TiO2-based microreactor
oai:www.repo.uni-hannover.de:123456789/922022-12-02T15:19:58Zcom_123456789_1col_123456789_8doc-type:Articleddc:540doc-type:Textopen_accessstatus-type:publishedVersion
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Albrecht, Moritz
author
Derrey, Insa Theresa
author
Horn, Ingo
author
Schuth, Stephan
author
Weyer, Stefan
author
2014
We have developed a new analytical setup for the determination of trace element concentrations in fluid inclusions by UV-fs-LA-ICP-MS. Laser ablation was performed at a low temperature of -40 degrees C by using a modified heating-freezing stage as the ablation cell. With this method it was possible to successfully analyse 53 of 55 frozen synthetic NaCl-H2O fluid inclusions in quartz, covering a size range between 8 mu m and 25 mu m down to a depth of 50 mu m. The high success rate could be achieved as the 194 nm UV-fs-laser allows excellent control over the opening procedure of frozen fluid inclusions. Trace element analyses were performed with a fast scanning magnetic sector field ICP-MS. The lower limits of detection for fluid inclusion analysis vary from 0.1 mu g g(-1) (for Bi-209) to 10 mu g g(-1) (for K-39). The typical analytical uncertainty, depending on the element and respective concentration level, ranges between 10% and 30% (1RSD), based on the reproducibility of experimentally synthesized fluid inclusions. All elements from a stock solution, which behaved inert during the HP/HT experiments (B, K, Cd, Te, Tl, Pb and Bi), could be recovered in the synthetic inclusions at concentrations that correspond within their specific analytical uncertainties to their original concentration of 53 mu g g(-1). The method represents a highly efficient tool for the determination of accurate trace element data on low concentration levels in small fluid inclusions with a high success rate of >90%. The latter is particularly advantageous considering the commonly time consuming characterization of fluid inclusions.
Albrecht, Moritz; Derrey, Insa Theresa; Horn, Ingo; Schuth, Stephan; Weyer, Stefan: Quantification of trace element contents in frozen fluid inclusions by UV-fs-LA-ICP-MS analysis. In: Journal of Analytical Atomic Spectrometry 29 (2014), Nr. 6, S. 1034-104. DOI: http://dx.doi.org/10.1039/c4ja00015c
http://www.repo.uni-hannover.de/handle/123456789/92
http://dx.doi.org/10.15488/74
femtosecond laser-ablation
plasma-mass-spectrometry
multielement analysis
melt inclusions
fractionation
microanalysis
h2o-nacl
metal
Quantification of trace element contents in frozen fluid inclusions by UV-fs-LA-ICP-MS analysis
oai:www.repo.uni-hannover.de:123456789/932022-12-02T16:11:40Zcom_123456789_1col_123456789_8doc-type:Articleddc:540doc-type:Textopen_accessstatus-type:publishedVersion
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Bloh, Jonathan Z.
author
Dillert, Ralf
author
Bahnemann, Detlef W.
author
2014
We recently reported a highly active photocatalyst, ruthenium-modified zinc oxide, which was found to be able to utilise the red part of the visible light spectrum for photocatalytic reactions [Bloh et al., Environ. Sci. Pollut. Res., 2012, 19, 3688-3695]. However, the origin and mechanism of the observed activity as well as the nature of the photoactive centres are still unknown. Herein, we expand on that by reporting a series of experiments specifically designed to unravel the mechanism of the visible light induced photocatalytic reactions. The absolute potentials of the valence and the conduction band edge are identified by the combined use of electrochemical impedance and UV-vis diffuse reflectance spectroscopy. The conduction band electron and the valence band hole activity are assessed through a novel approach tracing their signature oxidative species, i.e., hydrogen peroxide and hydroxyl radicals, respectively. Oxygen reduction currents are measured at different potentials to investigate the role of molecular oxygen as an electron scavenger as well as the underlying reduction pathways. Additionally, the photocatalytic activity of the samples is verified using another (ISO standard) degradation test, the gas-phase oxidation of nitric oxide. The experimental results reveal that the employed synthetic route yields a unique mixture of ruthenium(VI)-doped zinc oxide and ruthenium(VI) oxide particles with both forms of the ruthenium playing their own independent role in the enhancement of the photocatalytic activity. The ruthenium ions acting as dopants enable a better charge separation as well as the absorption of red light resulting in the direct promotion of electrons from the Ru(VI)-species to the conduction band. Both, the conduction band electrons and the thus formed Ru(VII) subsequently participate in the degradation of the pollutant molecules. The ruthenium dioxide particles, on the other hand, act as catalysts increasing the efficiency of the reaction by improving the oxygen reduction properties of the material.
Bloh, Jonathan Z.; Dillert, Ralf; Bahnemann, Detlef W.: Ruthenium-modified zinc oxide, a highly active vis-photocatalyst: the nature and reactivity of photoactive centres. In: Physical Chemistry Chemical Physics 16 (2014), Nr. 12, S. 5833-5845. DOI: http://dx.doi.org/10.1039/c3cp55136a
http://www.repo.uni-hannover.de/handle/123456789/93
http://dx.doi.org/10.15488/75
visible-light photocatalysis
heterogeneous photocatalysis
tio2 photocatalysis
titanium-dioxide
electronic-structure
driven photocatalysts
reduction reaction
optical properties
organic peroxides
alkaline-solution
Ruthenium-modified zinc oxide, a highly active vis-photocatalyst: the nature and reactivity of photoactive centres
oai:www.repo.uni-hannover.de:123456789/942022-12-02T19:24:35Zcom_123456789_15col_123456789_16doc-type:BookPartddc:830doc-type:Textopen_accessstatus-type:publishedVersion
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Tempel, Bernhard
author
2014
Mehrfach setzt der deutsche Dichter Gerhart Hauptmann (1862-1946) zwischen 1906 und 1942 Schlesien und Sparta in Beziehung. Im Reisetagebuch seiner Griechenlandreise erinnert ihn die Landschaft Spartas an die schlesische Landwirtschaftsidylle und eine Liebschaft während seiner Ausbildung in Lederose. Der veröffentlichte Reisebericht 'Griechischer Frühling' bezieht die Bevölkerungspolitik Spartas nach den Lykurgischen Gesetzen ein, die der deutschen Eugenik (von Hauptmanns Freund Alfred Ploetz 1895 als "Rassenhygiene" inauguriert) als vorbildlich galten. Zu einer Entgegensetzung von Sparta und Schlesien, in deren Landschaften er weiterhin Gemeinsamkeiten sieht, kommt Hauptmann 1922 in einem Paralipomenon zum Fragment gebliebenen Roman 'Der neue Chistophorus', wo der sein idealisiertes Selbstbild, den Bergpater, erklären läßt, spartanisches Freiheitsdrang werde in Schlesien nie heimisch sein. Vollends kritisch wird schließlich der Blick auf Sparta Ende der 1930er Jahre: Hauptmann begreift dann Schlesien als Land der Mischung und seine Familie als "Kolonisten"; es deutet sich in Tagebuchaufzeichnungen an, daß er Schlesien als Gegenmodell zu Sparta entwirft, dem (nach Ernst Baltrusch) "ersten totalitären Staat der Weltgeschichte", in dem Kunst - für Hauptmann das Maß aller Dinge - gegenüber der einseitig auf körperliche Tauglichkeit des Nachwuchses und Reinheit der Rasse ausgerichteten keinen Platz hat. Die Analogien zwischen der Rassenpolitik im Dritten Reich und Sparta (auch in zeitgenössischen Berufungen auf Sparta) nahm er wahr und lehnte beides ab.
Tempel, Bernhard: Schlesien versus Sparta. Gerhart Hauptmanns Besinnung auf schlesische Identität im Kontext der Rassenideologie. In: Das deutsche Kulturerbe in Schlesien : Fragen und Perspektiven / Mańko-Matysiak, Anna; Overgaauw, Eef; Weger, Tobias (Hrsg.). - München : Oldenbourg, 2014. - S. 171-184. (Schriften des Bundesinstituts für Kultur und Geschichte der Deutschen im Östlichen Europa ; 51). ISBN: 978-3-486-75425-4
http://www.repo.uni-hannover.de/handle/123456789/94
http://dx.doi.org/10.15488/76
Hauptmann, Gerhart
Eugenik
Sparta
Schlesien
Schlesien versus Sparta. Gerhart Hauptmanns Besinnung auf schlesische Identität im Kontext der Rassenideologie
oai:www.repo.uni-hannover.de:123456789/952022-12-02T18:24:34Zcom_123456789_1col_123456789_5doc-type:WorkingPaperddc:340doc-type:Textopen_accessstatus-type:publishedVersion
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Wolf, Christian
author
2014-09
Die prozessrechtliche Abteilung des 70. Deutschen Juristentags beschäftigt sich mit der Frage, ob ZPO und GVG noch zeitgemäß sind, um den gewandelten Anforderungen an den Zivilprozess Genüge tun zu können. Die Fragestellung ist für unser Rechtssystem hoch bedeutend. Der gleiche Zugang zu Gericht, die Chancengleichheit und Fairness vor Gericht sowie die Schnelligkeit und Effizienz der Gerichtsverfahren sind für den Rechtsstaat schlicht konstitutiv.
Zivilprozess in Zahlen : zum 70. Deutscher Juristentag in Hannover / Christian Wolf [Hrsg.]. - Hannover : Leibniz Universität Hannover. Institut für Prozess- und Anwaltsrecht, 2014. - 70 S. (IPA Working Paper ; 1/2014). URL: http://www.jura.uni-hannover.de/workingpapers.html
http://www.repo.uni-hannover.de/handle/123456789/95
http://dx.doi.org/10.15488/77
Zivilprozess
Statistik
ZPO
Zivilprozessordnung
Entwicklung
DJT
Deutscher Juristentag
Schiedsgerichtsbarkeit
Zivilprozess in Zahlen : zum 70. Deutscher Juristentag in Hannover
oai:www.repo.uni-hannover.de:123456789/962022-12-02T15:12:32Zcom_123456789_1col_123456789_7doc-type:Articledoc-type:Textopen_accessddc:530status-type:publishedVersion
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Popov, Alexander D.
author
2015
We consider the Yang-Mills equations with a matrix gauge group G on the de Sitter dS4, anti-de Sitter AdS4 and Minkowski R3,1R3,1 spaces. On all these spaces one can introduce a doubly warped metric in the form View the MathML sourceds2=−du2+f2dv2+h2dsH22, where f and h are the functions of u and View the MathML sourcedsH22 is the metric on the two-dimensional hyperbolic space H2H2. We show that in the adiabatic limit, when the metric on H2H2 is scaled down, the Yang–Mills equations become the sigma-model equations describing harmonic maps from a two-dimensional manifold (dS2, AdS2 or R1,1R1,1, respectively) into the based loop group ΩG=C∞(S1,G)/GΩG=C∞(S1,G)/G of smooth maps from the boundary circle S1=∂H2S1=∂H2 of H2H2 into the gauge group G. For compact groups G these harmonic map equations are reduced to equations of geodesics on ΩG, solutions of which yield magnetic-type configurations of Yang–Mills fields. The group ΩG naturally acts on their moduli space.
Popov, Alexander D.: Loop groups in Yang-Mills theory. In: Physics Letters B 748 (2015), S. 439-442. DOI: http://dx.doi.org/10.1016/j.physletb.2015.07.041
http://www.repo.uni-hannover.de/handle/123456789/96
http://dx.doi.org/10.15488/78
Loop groups in Yang-Mills theory
oai:www.repo.uni-hannover.de:123456789/972022-12-02T15:19:56Zcom_123456789_1col_123456789_7doc-type:Articledoc-type:Textopen_accessddc:530status-type:publishedVersion
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Junghans, Daniel
author
Schmidt, Daniel
author
Zagermann, Marco
author
2014
We study AdS(7) vacua of massive type IIA string theory compactified on a 3-sphere with H-3 flux and anti-D6-branes. In such backgrounds, the anti-brane backreaction is known to generate a singularity in the H-3 energy density, whose interpretation has not been understood so far. We first consider supersymmetric solutions of this setup and give an analytic proof that the flux singularity is resolved there by a polarization of the anti-D6-branes into a D8-brane, which wraps a finite 2-sphere inside of the compact space. To this end, we compute the potential for a spherical probe D8-brane on top of a background with backreacting anti-D6-branes and show that it has a local maximum at zero radius and a local minimum at a finite radius of the 2-sphere. The polarization is triggered by a term in the potential due to the AdS curvature and does therefore not occur in non-compact setups where the 7d external spacetime is Minkowski. We furthermore find numerical evidence for the existence of non-supersymmetric solutions in our setup. This is supported by the observation that the general solution to the equations of motion has a continuous parameter that is suggestive of a modulus and appears to control supersymmetry breaking. Analyzing the polarization potential for the non-supersymmetric solutions, we find that the flux singularities are resolved there by brane polarization as well.
Junghans, Daniel; Schmidt, Daniel; Zagermann, Marco: Curvature-induced resolution of anti-brane singularities. In: Journal of High Energy Physics 2014 (2014), Nr. 10. DOI: http://dx.doi.org/10.1007/JHEP10(2014)034
http://www.repo.uni-hannover.de/handle/123456789/97
http://dx.doi.org/10.15488/79
Flux compactifications; D-branes; Superstring Vacua
Curvature-induced resolution of anti-brane singularities
oai:www.repo.uni-hannover.de:123456789/992022-12-02T15:12:32Zcom_123456789_1col_123456789_7doc-type:Articledoc-type:Textopen_accessddc:530status-type:publishedVersion
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Ivanov, Evgeny A.
author
Lechtenfeld, Olaf
author
Zupnik, Boris M.
author
2015
The coset Sp(2, R)/U(1) is parametrized by two real scalar fields. We generalize the formalism of auxiliary tensor (bispinor) fields in U(1) self-dual nonlinear models of abelian gauge fields to the case of Sp(2, R) self-duality. In this new formulation, Sp(2, R) duality of the nonlinear scalar-gauge equations of motion is equivalent to an Sp(2, R) invariance of the auxiliary interaction. We derive this result in two different ways, aiming at its further application to supersymmetric theories. We also consider an extension to interactions with higher derivatives.
Ivanov, EvgenyA; Lechtenfeld, Olaf; Zupnik, Boris M.: Auxiliary tensor fields for Sp(2, R) self-duality. In: Journal of High Energy Physics 2015 (2015), Nr. 3. DOI: http://dx.doi.org/10.1007/JHEP03(2015)123
http://www.repo.uni-hannover.de/handle/123456789/99
http://dx.doi.org/10.15488/81
Duality in Gauge Field Theories
Global Symmetries
Auxiliary tensor fields for Sp(2, R) self-duality
oai:www.repo.uni-hannover.de:123456789/1002022-12-02T15:12:32Zcom_123456789_1col_123456789_7doc-type:Articledoc-type:Textopen_accessddc:530status-type:publishedVersion
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Haupt, Alexander S.
author
Lechtenfeld, Olaf
author
Musaev, Edvard T.
author
2014
We consider (1+3)-dimensional domain wall solutions of heterotic supergravity on a six-dimensional warped nearly Kähler manifold X 6 in the presence of gravitational and gauge instantons of tanh-kink type as constructed in [1]. We include first order α′ corrections to the heterotic supergravity action, which imply a non-trivial Yang-Mills sector and Bianchi identity. We present a variety of solutions, depending on the choice of instantons, for the special case in which the SU(3) structure on X 6 satisfies W1¯¯¯=0. The solutions preserve two real supercharges, which corresponds to N=1/2 supersymmetry from the four-dimensional point of view. Besides serving as a useful framework for collecting existing solutions, the formulation in terms of dynamic SU(3) structures utilized here allows us to obtain new solutions in as yet unexplored corners of the instanton configuration space. Our approach thus offers a unified description of the embedding of tanh-kink-type instantons into half-BPS solutions of heterotic supergravity where the internal six-dimensional manifold has a warped nearly Kähler geometry.
Haupt, Alexander S.; Lechtenfeld, Olaf; Musaev, Edvard T.: Order α′ heterotic domain walls with warped nearly Kähler geometry. In: Journal of High Energy Physics 2014 (2014), Nr. 11. DOI: http://dx.doi.org/10.1007/JHEP11(2014)152
http://www.repo.uni-hannover.de/handle/123456789/100
http://dx.doi.org/10.15488/82
Flux compactifications
Solitons Monopoles
Instantons
Supergravity Models
Order α′ heterotic domain walls with warped nearly Kähler geometry
oai:www.repo.uni-hannover.de:123456789/1012022-12-02T15:15:01Zcom_123456789_1col_123456789_7doc-type:Articledoc-type:Textopen_accessddc:530status-type:publishedVersion
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Hakobyan, Tigran
author
Karakhanyan, David
author
Lechtenfeld, Olaf
author
2014
We investigate the integrals of motion of general conformal mechanical systems with and without confining harmonic potential as well as of the related angular subsystems, by employing the sl(2,R) algebra and its representations. In particular, via the tensor product of two representations we construct new integrals of motion from old ones, both in the classical and in the quantum case. Furthermore, the temporally periodic observables (including the integrals) of the angular subsystem are explicitly related to those of the full system in a confining harmonic potential. The techniques are illustrated for the rational Calogero models and their angular subsystems, where they generalize known methods for obtaining conserved charges beyond the Liouville ones.
Hakobyan, Tigran; Karakhanyan, David; Lechtenfeld, Olaf: The structure of invariants in conformal mechanics. In: Nuclear Physics B 886 (2014), S. 399-420. DOI: http://dx.doi.org/10.1016/j.nuclphysb.2014.07.008
http://www.repo.uni-hannover.de/handle/123456789/101
http://dx.doi.org/10.15488/83
calogero-moser system
n-body problems
integrable systems
lie-algebras
hamiltonian systems
quantum-mechanics
sutherland model
one-dimension
black-holes
superintegrability
The structure of invariants in conformal mechanics
oai:www.repo.uni-hannover.de:123456789/1022022-12-02T15:12:32Zcom_123456789_1col_123456789_7doc-type:Articledoc-type:Textopen_accessddc:530status-type:publishedVersion
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Gray, James
author
Haupt, Alexander S.
author
Lukas, Andre
author
2014
We investigate the mathematical properties of the class of Calabi-Yau four-folds recently found in ref. [1]. This class consists of 921,497 configuration matrices which correspond to manifolds that are described as complete intersections in products of projective spaces. For each manifold in the list, we compute the full Hodge diamond as well as additional topological invariants such as Chern classes and intersection numbers. Using this data, we conclude that there are at least 36,779 topologically distinct manifolds in our list. We also study the fibration structure of these manifolds and find that 99.95 percent can be described as elliptic fibrations. In total, we find 50,114,908 elliptic fibrations, demonstrating the multitude of ways in which many manifolds are fibered. A sub-class of 26,088,498 fibrations satisfy necessary conditions for admitting sections. The complete data set can be downloaded here.
Gray, James; Haupt, AlexanderS; Lukas, Andre: Topological invariants and fibration structure of complete intersection Calabi-Yau four-folds. In: Journal of High Energy Physics 2014 (2014), Nr. 9. DOI: http://dx.doi.org/10.1007/JHEP09(2014)093
http://www.repo.uni-hannover.de/handle/123456789/102
http://dx.doi.org/10.15488/84
F-Theory
Differential
Algebraic Geometry
Superstring Vacua
Topological invariants and fibration structure of complete intersection Calabi-Yau four-folds
oai:www.repo.uni-hannover.de:123456789/1032022-12-02T15:12:32Zcom_123456789_1col_123456789_7doc-type:Articledoc-type:Textopen_accessddc:530status-type:publishedVersion
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Graña, Mariana
author
Louis, Jan
author
Theis, Ulrich
author
Waldram, Daniel
author
2015
We investigate quantum corrections to the classical four-dimensional low-energy effective action of type II string theory compactified on SU(3) structure geometries. Various methods previously developed for Calabi-Yau compactifications are adopted to constrain - under some simple assumptions about the low-energy degrees of freedom - the leading perturbative corrections to the moduli space metrics in both α′ and the string coupling constant. We find that they can be parametrized by a moduli dependent function in the hypermultiplet sector and a constant in the vector multiplet sector. We argue that under specific additional assumption they take - in complete analogy to the Calabi-Yau case - a universal form which depends only on the Euler characteristic of the six-dimensional compact space.
Graña, Mariana; Louis, Jan; Theis, Ulrich; Waldram, Daniel: Quantum corrections in string compactifications on SU(3) structure geometries. In: Journal of High Energy Physics 2015 (2015), Nr.1. DOI: http://dx.doi.org/10.1007/JHEP01(2015)057
http://www.repo.uni-hannover.de/handle/123456789/103
http://dx.doi.org/10.15488/85
Supersymmetric Effective Theories
Flux compactifications
Superstring Vacua
Quantum corrections in string compactifications on SU(3) structure geometries
oai:www.repo.uni-hannover.de:123456789/1042022-12-02T15:15:01Zcom_123456789_1col_123456789_7doc-type:Articledoc-type:Textopen_accessddc:530status-type:publishedVersion
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Frahm, Holger
author
Seel, Alexander
author
2014
We study the emergence of non-compact degrees of freedom in the low energy effective theory for a class of Z2Z2-staggered six-vertex models. In the finite size spectrum of the vertex model this shows up through the appearance of a continuum of critical exponents. To analyze this part of the spectrum we derive a set of coupled nonlinear integral equations from the Bethe ansatz solution of the vertex model which allow to compute the energies of the system for a range of anisotropies and of the staggering parameter. The critical theory is found to be independent of the staggering. Its spectrum and density of states coincide with the SL(2,R)/U(1)SL(2,R)/U(1) Euclidean black hole conformal field theory which has been identified previously in the continuum limit of the vertex model for a particular ‘self-dual’ choice of the staggering. We also study the asymptotic behavior of subleading corrections to the finite size scaling and discuss our findings in the context of the conformal field theory.
Frahm, Holger; Seel, Alexander: The staggered six-vertex model: Conformal invariance and corrections to scaling. In: Nuclear Physics B 879 (2014), S. 382-406. DOI: http://dx.doi.org/10.1016/j.nuclphysb.2013.12.015
http://www.repo.uni-hannover.de/handle/123456789/104
http://dx.doi.org/10.15488/86
lattice potts-model
sl(2,r) wzw model
operator content
heisenberg chain
superspin chain
continuum-limit
quantum chains
critical-point
central charge
field-theory
The staggered six-vertex model: Conformal invariance and corrections to scaling
oai:www.repo.uni-hannover.de:123456789/1052022-12-02T15:12:32Zcom_123456789_1col_123456789_7doc-type:Articledoc-type:Textopen_accessddc:530status-type:publishedVersion
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Frahm, Holger
author
Martins, Márcio J.
author
2015
The low energy spectrum of a spin chain with OSp(3|2)supergroup symmetry is studied based on the Bethe ansatz solution of the related vertex model. This model is a lattice realization of intersecting loops in two dimensions with loop fugacity z=1which provides a framework to study the critical properties of the unusual low temperature Goldstone phase of the O(N)sigma model for N=1in the context of an integrable model. Our finite-size analysis provides strong evidence for the existence of continua of scaling dimensions, the lowest of them starting at the ground state. Based on our data we conjecture that the so-called watermelon correlation functions decay logarithmically with exponents related to the quadratic Casimir operator of OSp(3|2). The presence of a continuous spectrum is not affected by a change to the boundary conditions although the density of states in the continua appears to be modified.
Frahm, Holger; Martins, Márcio J.: Finite-size effects in the spectrum of the OSp(3|2) superspin chain. In: Nuclear Physics B 894 (2015), S. 665-684. DOI: http://dx.doi.org/10.1016/j.nuclphysb.2015.03.021
http://www.repo.uni-hannover.de/handle/123456789/105
http://dx.doi.org/10.15488/87
staggered 6-vertex model
conformal-invariance
continuum-limit
2 dimensions
lattice-gas
spin chain
point
Finite-size effects in the spectrum of the OSp(3|2) superspin chain
oai:www.repo.uni-hannover.de:123456789/1062022-12-02T15:15:01Zcom_123456789_1col_123456789_7doc-type:Articledoc-type:Textopen_accessddc:530status-type:publishedVersion
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Frahm, Holger
author
Karaiskos, Nikos
author
2014
We derive exact inversion identities satisfied by the transfer matrix of inhomogeneous interaction-round-a-face (IRF) models with arbitrary boundary conditions using the underlying integrable structure and crossing properties of the local Boltzmann weights. For the critical restricted solid-on-solid (RSOS) models these identities together with some information on the analytical properties of the transfer matrix deter-mine the spectrum completely and allow to derive the Bethe equations for both periodic and general open boundary conditions.
Frahm, Holger; Karaiskos, Nikos: Inversion identities for inhomogeneous face models. In: Nuclear Physics B 887 (2014), S. 423-440. DOI: http://dx.doi.org/10.1016/j.nuclphysb.2014.08.013
http://www.repo.uni-hannover.de/handle/123456789/106
http://dx.doi.org/10.15488/88
nondiagonal boundary terms
8-vertex sos model
xxz spin chain
bethe-ansatz
functional relations
reflection equation
field-theory
representation
Inversion identities for inhomogeneous face models
oai:www.repo.uni-hannover.de:123456789/1072022-12-02T15:15:01Zcom_123456789_1col_123456789_7doc-type:Articledoc-type:Textopen_accessddc:530status-type:publishedVersion
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Finch, Peter E.
author
Flohr, Michael
author
Frahm, Holger
author
2014
Starting from the fusion rules for the algebra SO(5)2we construct one-dimensional lattice models of interacting anyons with commuting transfer matrices of ‘interactions round the face’ (IRF) type. The con-served topological charges of the anyon chain are recovered from the transfer matrices in the limit of large spectral parameter. The properties of the models in the thermodynamic limit and the low energy excitations are studied using Bethe ansatz methods. Two of the anyon models are critical at zero temperature. From the analysis of the finite size spectrum we find that they are effectively described by rational conformal field theories invariant under extensions of the Virasoro algebra, namely WB2and WD5, respectively. The latter contains primaries with half and quarter spin. The modular partition function and fusion rules are derived and found to be consistent with the results for the lattice model.
Finch, Peter E.; Flohr, Michael; Frahm, Holger: Integrable anyon chains: From fusion rules to face models to effective field theories. In: Nuclear Physics B 889 (2014), S. 299-332. DOI: http://dx.doi.org/10.1016/j.nuclphysb.2014.10.017
http://www.repo.uni-hannover.de/handle/123456789/107
http://dx.doi.org/10.15488/89
condensed matter
strongly correlated electrons
high energy physics
theory
mathematical physics
conformal invariance
dynkin diagrams
lattice models
spin chain
w-algebras
q-operator
sos model
thermodynamics
construction
excitations
Integrable anyon chains: From fusion rules to face models to effective field theories
oai:www.repo.uni-hannover.de:123456789/1082022-12-02T15:12:32Zcom_123456789_1col_123456789_7doc-type:Articledoc-type:Textopen_accessddc:530status-type:publishedVersion
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Deser, Andreas
author
Lechtenfeld, Olaf
author
Popov, Alexander D.
author
2015
We consider the Hermitian Yang–Mills (instanton) equations for connections on vector bundles over a 2n-dimensional Kähler manifold Xwhich is a product Y×Zof p-and q-dimensional Riemannian manifold Yand Zwith p+q=2n. We show that in the adiabatic limit, when the metric in the Zdirection is scaled down, the gauge instanton equations on Y×Zbecome sigma-model instanton equations for maps from Yto the moduli space M(target space) of gauge instantons on Zif q≥4. For q<4we get maps from Yto the moduli space Mof flat connections on Z. Thus, the Yang–Mills instantons on Y×Zconverge to sigma-model instantons on Ywhile Zshrinks to a point. Put differently, for small volume of Z, sigma-model instantons on Ywith target space Mapproximate Yang–Mills instantons on Y×Z.
Deser, Andreas; Lechtenfeld, Olaf; Popov, Alexander D. (2015): Sigma-model limit of Yang–Mills instantons in higher dimensions. In: Nuclear Physics B 894, S. 361–373. DOI: http://dx.doi.org/10.1016/j.nuclphysb.2015.03.009
http://www.repo.uni-hannover.de/handle/123456789/108
http://dx.doi.org/10.15488/90
high energy physics
theory
mathematical physics
mathematics
differential geometry
stable vector-bundles
chern-simons theory
greater-than 4
gauge-theory
calibrated geometry
holonomy manifolds
fields
equations
connections
reduction
Sigma-model limit of Yang–Mills instantons in higher dimensions
oai:www.repo.uni-hannover.de:123456789/1092022-12-02T15:12:32Zcom_123456789_1col_123456789_7doc-type:Articledoc-type:Textopen_accessddc:530status-type:publishedVersion
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Correa, Francisco
author
Lechtenfeld, Olaf
author
Plyushchay, Mikhail
author
2014
It is long known that the rational Calogero model describing n identical particles on a line with inverse-square mutual interaction potential is quantum superintegrable. We review the (nonlinear) algebra of the conserved quantum charges and the intertwiners which relate the Liouville charges at couplings g and g±1. For integer values of g, these intertwiners give rise to additional conserved charges commuting with all Liouville charges and known since the 1990s. We give a direct construction of such a charge, the unique one being totally antisymmetric under particle permutations. It is of order 12 n(n−1)(2g−1) in the momenta and squares to a polynomial in the Liouville charges. With a natural Z 2 grading, this charge extends the algebra of conserved charges to a nonlinear supersymmetric one. We provide explicit expressions for intertwiners, charges and their algebra in the cases of two, three and four particles.
Correa, Francisco; Lechtenfeld, Olaf; Plyushchay, Mikhail: Nonlinear supersymmetry in the quantum Calogero model. In: J. High Energ. Phys. 2014 (2014), Nr. 4. DOI: http://dx.doi.org/10.1007/JHEP04(2014)151
http://www.repo.uni-hannover.de/handle/123456789/109
http://dx.doi.org/10.15488/91
Integrable Equations
Conformal Symmetry
W Symmetry
Extended Supersymmetry
Nonlinear supersymmetry in the quantum Calogero model
oai:www.repo.uni-hannover.de:123456789/1112022-12-02T15:15:01Zcom_123456789_1col_123456789_7doc-type:Articledoc-type:Textopen_accessddc:530status-type:publishedVersion
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Chatzistavrakidis, Athanasios
author
Jonke, Larisa
author
Lechtenfeld, Olaf
author
2014
We study some aspects of the generalized geometry of nilmanifolds and examine to which extent different types of fluxes can coexist on them. Nilmanifolds constitute a class of homogeneous spaces which are interesting in string compactifications with fluxes since they carry geometric flux by construction. They are generalized Calabi–Yau spaces and therefore simple examples of generalized geometry at work. We identify and classify Dirac structures on nilmanifolds, which are maximally isotropic subbundles closed under the Courant bracket. In the presence of non-vanishing fluxes, these structures are twisted and closed under appropriate extensions of the Courant bracket. Twisted Dirac structures on a nilmanifold may carry multiple coexistent fluxes of any type. We also show how dual Dirac structures combine to Courant algebroids and work out an explicit example where all types of generalized fluxes coexist. These results may be useful in the context of general flux compactifications in string theory.
Chatzistavrakidis, Athanasios; Jonke, Larisa; Lechtenfeld, Olaf: Dirac structures on nilmanifolds and coexistence of fluxes. In: Nuclear Physics B 883 (2014), S. 59-82. DOI: http://dx.doi.org/10.1016/j.nuclphysb.2014.03.013
http://www.repo.uni-hannover.de/handle/123456789/111
http://dx.doi.org/10.15488/93
high energy physics
theory
mathematical physics
poisson manifolds
lie bialgebroids
string theory
compactifications
tori
Dirac structures on nilmanifolds and coexistence of fluxes
oai:www.repo.uni-hannover.de:123456789/1122022-12-02T15:12:32Zcom_123456789_1col_123456789_7doc-type:Articledoc-type:Textopen_accessddc:530status-type:publishedVersion
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Bunk, Severin
author
Lechtenfeld, Olaf
author
Popov, Alexander D.
author
Sperling, Marcus
author
2015
We present a general procedure to construct 6-dimensional manifolds with SU(3)-structure from SU(2)-structure 5-manifolds. We thereby obtain half-flat cylinders and sine-cones over 5-manifolds with Sasaki-Einstein SU(2)-structure. They are nearly Kähler in the special case of sine-cones over Sasaki-Einstein 5-manifolds. Both half-flat and nearly Kähler 6-manifolds are prominent in flux compactifications of string theory. Subsequently, we investigate instanton equations for connections on vector bundles over these half-flat manifolds. A suitable ansatz for gauge fields on these 6-manifolds reduces the instanton equation to a set of matrix equations. We finally present some of its solutions and discuss the instanton configurations obtained this way.
Bunk, Severin; Lechtenfeld, Olaf; Popov, Alexander D; Sperling, Marcus: Instantons on conical half-flat 6-manifolds. In: Journal of High Energy Physics 2015 (2015), Nr. 1. DOI: http://dx.doi.org/10.1007/JHEP01(2015)030
http://www.repo.uni-hannover.de/handle/123456789/112
http://dx.doi.org/10.15488/94
Solitons Monopoles
Instantons
Flux compactifications
Differential Geometry
Algebraic Geometry
Instantons on conical half-flat 6-manifolds
oai:www.repo.uni-hannover.de:123456789/1132022-12-02T15:12:32Zcom_123456789_1col_123456789_7doc-type:Articledoc-type:Textopen_accessddc:530status-type:publishedVersion
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Bueno, P.
author
Chemissany, W.
author
Shahbazi, C.S
author
2014
We perform a thorough investigation of Lifshitz-like metrics with hyperscaling violation (hvLif) in four-dimensional theories of gravity coupled to an arbitrary number of scalars and vector fields, obtaining new solutions, electric, magnetic, and dyonic, that include the known ones as particular cases. After establishing some general results on the properties of purely hvLif solutions, we apply the previous formalism to the case of N=2, d=4 supergravity in the presence of Fayet–Iliopoulos terms, obtaining particular solutions to the t3-model, and explicitly embedding some of them in Type-IIB string theory.
Bueno, P.; Chemissany, W.; Shahbazi, C.S: On hvLif-like solutions in gauged Supergravity. In: The European Physical Journal C 74 (2014), Nr. 1. DOI: http://dx.doi.org/10.1140/epjc/s10052-013-2684-3
http://www.repo.uni-hannover.de/handle/123456789/113
http://dx.doi.org/10.15488/95
Gauge Coupling Constant
Hamiltonian Constraint
Scalar Field
Hyperscaling Violation
Attractor Point
Extremal Black Hole
Cosmological Constant
Dyonic Solution
Flat Direction
Coupling Function
Dilaton Field
Energy-momentum Tensor
Gravity Theory
Negative Cosmological Constant
black-holes
hyperscaling violation
supergravity
On hvLif-like solutions in gauged Supergravity
oai:www.repo.uni-hannover.de:123456789/1142022-12-02T15:12:32Zcom_123456789_1col_123456789_7doc-type:Articledoc-type:Textopen_accessddc:530status-type:publishedVersionddc:510
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Bizet, Nana G. Cabo
author
Kobayashi, Tatsuo
author
Peña, Damián K. Mayorga
author
Parameswaran, Susha L.
author
Schmitz, Matthias
author
Zavala, Ivonne
author
2014
We study discrete R-symmetries, which appear in the 4D low energy effective field theory derived from heterotic orbifold models. We derive the R-symmetries directly from the geometrical symmetries of the orbifolds. In particular, we obtain the corresponding R-charges by requiring that the couplings be invariant under these symmetries. This allows for a more general treatment than the explicit computations of correlation functions made previously by the authors, including models with discrete Wilson lines, and orbifold symmetries beyond plane-by-plane rotational invariance. The R-charges obtained in this manner differ from those derived in earlier explicit computations. We study the anomalies associated with these R-symmetries, and comment on the results.
Bizet, Nana G. Cabo; Kobayashi, Tatsuo; Peña, Damián K. Mayorga; Parameswaran, Susha L.; Schmitz, Matthias; Zavala, Ivonne: Discrete R-symmetries and anomaly universality in heterotic orbifolds. In: Journal of High Energy Physics 2014 (2014), Nr. 2. DOI: http://dx.doi.org/10.1007/JHEP02(2014)098
http://www.repo.uni-hannover.de/handle/123456789/114
http://dx.doi.org/10.15488/96
Wilson Line
Orbifold Model
Low Energy Effective Field Theory
Geometrical Symmetry
String Theory
Finite Symmetry
Explicit Computation
Heterotic String
Superstrings
Conformal Field Model
Discrete R-symmetries and anomaly universality in heterotic orbifolds
oai:www.repo.uni-hannover.de:123456789/1152022-12-02T15:12:32Zcom_123456789_1col_123456789_7doc-type:Articledoc-type:Textopen_accessddc:530status-type:publishedVersion
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Apruzzi, Fabio
author
Gautason, Fridrik Freyr
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Parameswaran, Susha L.
author
Zagermann, Marco
author
2015
We study to what extent Wilson lines in heterotic Calabi-Yau compactifications lead to non-trivial H-flux via Chern-Simons terms. Wilson lines are basic ingredients for Standard Model constructions but their induced H-flux may affect the consistency of the leading order background geometry and of the two-dimensional worldsheet theory. Moreover H-flux in heterotic compactifications would play an important role for moduli stabilization and could strongly constrain the supersymmetry breaking scale. We show how to compute H-flux and the corresponding superpotential, given an explicit complete intersection Calabi-Yau compactification and choice of Wilson lines. We do so by identifying large classes of special Lagrangian submanifolds in the Calabi-Yau, understanding how the Wilson lines project onto these submanifolds, and computing their Chern-Simons invariants. We illustrate our procedure with the quintic hypersurface as well as the split-bicubic, which can provide a potentially realistic three generation model.
Apruzzi, Fabio; Gautason, FridrikFreyr; Parameswaran, Susha; Zagermann, Marco (2015): Wilson lines and Chern-Simons flux in explicit heterotic Calabi-Yau compactifications. In: Journal of High Energy Physics 2015 (2015), Nr. 2. DOI: http://dx.doi.org/10.1007/JHEP02(2015)183
http://www.repo.uni-hannover.de/handle/123456789/115
http://dx.doi.org/10.15488/97
Wilson Line
Complete Intersection
Special Lagrangian Submanifolds
Modulo Stabilization
Supersymmetry Breaking Scale
Chern-Simons Term
Calabi-Yau Compactifications
String Model
Large Classis
Heterotic Compactifications
Flux Compactifications
Heterotic Strings
Superstrings
Superstring Vacua
Wilson lines and Chern-Simons flux in explicit heterotic Calabi-Yau compactifications
oai:www.repo.uni-hannover.de:123456789/1182022-12-02T15:12:32Zcom_123456789_1col_123456789_7doc-type:Articledoc-type:Textopen_accessddc:530status-type:publishedVersion
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Apruzzi, Fabio
author
Fazzi, Marco
author
Passias, Achilleas
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Rosa, Dario
author
Tomasiello, Alessandro
author
2014
Very few AdS6 × M 4 supersymmetric solutions are known: one in massive IIA, and two IIB solutions dual to it. The IIA solution is known to be unique; in this paper, we use the pure spinor approach to give a classification for IIB supergravity. We reduce the problem to two PDEs on a two-dimensional space Σ. M 4 is then a fibration of S 2 over Σ; the metric and fluxes are completely determined in terms of the solution to the PDEs. The results seem likely to accommodate near-horizon limits of (p, q)-fivebrane webs studied in the literature as a source of CFT5’s. We also show that there are no AdS6 solutions in eleven-dimensional supergravity.
Apruzzi, Fabio; Fazzi, Marco; Passias, Achilleas; Rosa, Dario; Tomasiello, Alessandro: AdS6 solutions of type II supergravity. In: Journal of High Energy Physics 2014 (2014), Nr. 11. DOI: http://dx.doi.org/10.1007/JHEP11(2014)099
http://www.repo.uni-hannover.de/handle/123456789/118
http://dx.doi.org/10.15488/100
Flux Compactifications
AdS-CFT Correspondence
Pure Spinor
Near-horizon Limit
Massive IIA
Supersymmetric Solution
IIB Supergravity
Eleven-dimensional Supergravity
Two-dimensional Space
AdS6 solutions of type II supergravity
oai:www.repo.uni-hannover.de:123456789/1192022-12-02T16:10:14Zcom_123456789_1col_123456789_8doc-type:Articleddc:540doc-type:Textopen_accessstatus-type:publishedVersion
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Strauss, Florian
author
Hüger, Erwin
author
Heitjans, Paul
author
Trouillet, Vanessa
author
Bruns, Michael
author
Schmidt, Harald
author
2015
Amorphous lithium–silicon compounds are promising materials in order to improve pure silicon as a high-capacity anode material in lithium-ion batteries. We demonstrated that it is possible to produce amorphous LixSi (x ~ 0.4) thin films by reactive ion-beam cosputtering of a segmented solid state target composed of metallic lithium and elemental silicon. At the surface a graded LixSiOy layer of some nanometer thickness is formed by contact with air which seems to prevent decomposition of the LixSi.
Strauß, Florian; Hüger, Erwin; Heitjans, Paul; Trouillet, Vanessa; Bruns, Michael; Schmidt, Harald: Li–Si thin films for battery applications produced by ion-beam co-sputtering. In: RSC Advances 5 (2015), Nr. 10, S. 7192–7195. DOI: http://dx.doi.org/10.1039/c4ra14458a
http://www.repo.uni-hannover.de/handle/123456789/119
http://dx.doi.org/10.15488/101
solid-state nmr
photoelectron-spectroscopy
lithium
silicon
electrodes
Li12Si7
relaxometry
lithiation
stability
anodes
Festkörper-NMR
Photoelektronenspektroskopie
Lithium
Silizium
Elektroden
Li12Si7
Relaxometrie
Lithiierung
Anode
Li-Si thin films for battery applications produced by ion-beam co-sputtering
oai:www.repo.uni-hannover.de:123456789/1202022-12-02T16:11:41Zcom_123456789_1col_123456789_8doc-type:Articledoc-type:Textopen_accessstatus-type:publishedVersionddc:580ddc:570
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Yim, Bunlong
author
Winkelmann, Traud
author
Ding, Guo-Chun
author
Smalla, Kornelia
author
2015-11-06
Replant disease (RD) severely affects apple production in propagation tree nurseries and in fruit orchards worldwide. This study aimed to investigate the effects of soil disinfection treatments on plant growth and health in a biotest in two different RD soil types under greenhouse conditions and to link the plant growth status with the bacterial community composition at the time of plant sampling. In the biotest performed we observed that the aboveground growth of apple rootstock M26 plants after 8 weeks was improved in the two RD soils either treated at 50°C or with gamma irradiation compared to the untreated RD soils. Total community DNA was extracted from soil loosely adhering to the roots and quantitative real-time PCR revealed no pronounced differences in 16S rRNA gene copy numbers. 16S rRNA gene-based bacterial community analysis by denaturing gradient gel electrophoresis (DGGE) and 454-pyrosequencing revealed significant differences in the bacterial community composition even after 8 weeks of plant growth. In both soils, the treatments affected different phyla but only the relative abundance of Acidobacteria was reduced by both treatments. The genera Streptomyces, Bacillus, Paenibacillus, and Sphingomonas had a higher relative abundance in both heat treated soils, whereas the relative abundance of Mucilaginibacter, Devosia, and Rhodanobacter was increased in the gamma-irradiated soils and only the genus Phenylobacterium was increased in both treatments. The increased abundance of genera with potentially beneficial bacteria, i.e., potential degraders of phenolic compounds might have contributed to the improved plant growth in both treatments.
Yim, Bunlong; Winkelmann, Traud; Ding, Guo-Chun; Smalla, Kornelia: Different bacterial communities in heat and gamma irradiation treated replant disease soils revealed by 16S rRNA gene analysis – contribution to improved aboveground apple plant growth? In: Frontiers in Microbiology 6 (2015), Nr. 8. DOI: http://dx.doi.org/10.3389/fmicb.2015.01224
http://www.repo.uni-hannover.de/handle/123456789/120
http://dx.doi.org/10.15488/102
biotest
apple replant disease
DGGE
qPCR
pyrosequencing
bacterial community composition
bacterial diversity
Biotest
Apfel
Nachbaukrankheit
DGGE
Denaturierungsgradientengelelektrophorese
qPCR
quantitative Echtzeit PCR
Quantitative Real-Time PCR
Pyrosequenzierung
Bakteriengemeinschaft
Zusammensetzung
bakterielle Vielfalt
Vielfalt
Bakterien
Different bacterial communities in heat and gamma irradiation treated replant disease soils revealed by 16S rRNA gene analysis – contribution to improved aboveground apple plant growth?
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