TY  - JOUR
A1  - Folikumah, Makafui Yao
A1  - Neffe, Axel T.
A1  - Behl, Marc
A1  - Lendlein, Andreas
T1  - Thiol Michael-Type reactions of optically active mercapto-acids in aqueous medium
JF  - MRS advances : a journal of the Materials Research Society
N2  - Defined chemical reactions in a physiological environment are a prerequisite for the in situ synthesis of implant materials potentially serving as matrix for drug delivery systems, tissue fillers or surgical glues. ‘Click’ reactions like thiol Michael-type reactions have been successfully employed as bioorthogonal reaction. However, due to the individual stereo-electronic and physical properties of specific substrates, an exact understanding their chemical reactivity is required if they are to be used for in-situ biomaterial synthesis. The chiral (S)-2-mercapto-carboxylic acid analogues of L-phenylalanine (SH-Phe) and L-leucine (SH-Leu) which are subunits of certain collagenase sensitive synthetic peptides, were explored for their potential for in-situ biomaterial formation via the thiol Michael-type reaction.

In model reactions were investigated the kinetics, the specificity and influence of stereochemistry of this reaction. We could show that only reactions involving SH-Leu yielded the expected thiol-Michael product. The inability of SH-Phe to react was attributed to the steric hindrance of the bulky phenyl group. In aqueous media, successful reaction using SH-Leu is thought to proceed via the sodium salt formed in-situ by the addition of NaOH solution, which was intented to aid the solubility of the mercapto-acid in water. Fast reaction rates and complete acrylate/maleimide conversion were only realized at pH 7.2 or higher suggesting the possible use of SH-Leu under physiological conditions for thiol Michael-type reactions. This method of in-situ formed alkali salts could be used as a fast approach to screen mercapto-acids for thio Michael-type reactions without the synthesis of their corresponding esters.
KW  - biomaterial
KW  - biomedical
KW  - biomimetic (chemical reaction)
KW  - chemical synthesis
Y1  - 2019
U6  - https://doi.org/10.1557/adv.2019.308
SN  - 2059-8521
VL  - 4
IS  - 46-47
SP  - 2515
EP  - 2525
PB  - Springer Nature Switzerland AG
CY  - Cham
ER  - 
TY  - GEN
A1  - Kaastra, Jelle S.
A1  - Paerels, Frits B.S.
A1  - Durret, Florence
A1  - Schindler, Sabine
A1  - Richter, Philipp
T1  - Thermal radiation processes
T2  - Postprints der Universität Potsdam : Mathematisch Naturwissenschaftliche Reihe
N2  - We discuss the different physical processes that are important to understand the thermal X-ray emission and absorption spectra of the diffuse gas in clusters of galaxies and the warm-hot intergalactic medium. The ionisation balance, line and continuum emission and absorption properties are reviewed and several practical examples are given that illustrate the most important diagnostic features in the X-ray spectra.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 891 
KW  - atomic processes
KW  - radiation mechanisms: thermal
KW  - intergalactic medium
KW  - X-rays: general
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-436220
SN  - 1866-8372
IS  - 891
SP  - 155
EP  - 190
ER  - 
TY  - JOUR
A1  - Serrano-Munoz, Itziar
A1  - Mishurova, Tatiana
A1  - Thiede, Tobias
A1  - Sprengel, Maximilian
A1  - Kromm, Arne
A1  - Nadammal, Naresh
A1  - Nolze, Gert
A1  - Saliwan-Neumann, Romeo
A1  - Evans, Alexander
A1  - Bruno, Giovanni
T1  - The residual stress in as-built laser powder bed fusion IN718 alloy as a consequence of the scanning strategy induced microstructure
JF  - Scientific reports
N2  - The effect of two types of scanning strategies on the grain structure and build-up of Residual Stress (RS) has been investigated in an as-built IN718 alloy produced by Laser Powder Bed Fusion (LPBF). The RS state has been investigated by X-ray diffraction techniques. The microstructural characterization was performed principally by Electron Backscatter Diffraction (EBSD), where the application of a post-measurement refinement technique enables small misorientations (< 2 degrees) to be resolved. Kernel average misorientation (KAM) distributions indicate that preferably oriented columnar grains contain higher levels of misorientation, when compared to elongated grains with lower texture. The KAM distributions combined with X-ray diffraction stress maps infer that the increased misorientation is induced via plastic deformation driven by the thermal stresses, acting to self-relieve stress. The possibility of obtaining lower RS states in the build direction as a consequence of the influence of the microstructure should be considered when envisaging scanning strategies aimed at the mitigation of RS.
KW  - EBSD
KW  - components
KW  - deposition
KW  - diffraction
KW  - distortion
KW  - heat-treatment
KW  - mechanical properties
KW  - melting slm
KW  - superalloys
KW  - texture
Y1  - 2020
U6  - https://doi.org/10.1038/s41598-020-71112-9
SN  - 2045-2322
VL  - 10
IS  - 1
PB  - Macmillan Publishers Limited, part of Springer Nature
CY  - London
ER  - 
TY  - GEN
A1  - Sarhan, Radwan Mohamed
A1  - Koopman, Wouter-Willem Adriaan
A1  - Schuetz, Roman
A1  - Schmid, Thomas
A1  - Liebig, Ferenc
A1  - Koetz, Joachim
A1  - Bargheer, Matias
T1  - The importance of plasmonic heating for the plasmondriven photodimerization of 4-nitrothiophenol
T2  - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe
N2  - Metal nanoparticles form potent nanoreactors, driven by the optical generation of energetic electrons and nanoscale heat. The relative influence of these two factors on nanoscale chemistry is strongly debated. This article discusses the temperature dependence of the dimerization of 4-nitrothiophenol (4-NTP) into 4,4′-dimercaptoazobenzene (DMAB) adsorbed on gold nanoflowers by Surface-Enhanced Raman Scattering (SERS). Raman thermometry shows a significant optical heating of the particles. The ratio of the Stokes and the anti-Stokes Raman signal moreover demonstrates that the molecular temperature during the reaction rises beyond the average crystal lattice temperature of the plasmonic particles. The product bands have an even higher temperature than reactant bands, which suggests that the reaction proceeds preferentially at thermal hot spots. In addition, kinetic measurements of the reaction during external heating of the reaction environment yield a considerable rise of the reaction rate with temperature. Despite this significant heating effects, a comparison of SERS spectra recorded after heating the sample by an external heater to spectra recorded after prolonged illumination shows that the reaction is strictly photo-driven. While in both cases the temperature increase is comparable, the dimerization occurs only in the presence of light. Intensity dependent measurements at fixed temperatures confirm this finding.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 698 
KW  - enhanced raman-scattering
KW  - charge-transfer
KW  - metal
KW  - nanoparticles
KW  - catalysis
KW  - AU
KW  - 4-nitrobenzenethiol
KW  - aminothiophenol
KW  - photocatalysis
KW  - wavelength
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-427197
SN  - 1866-8372
IS  - 698
ER  - 
TY  - JOUR
A1  - Sarhan, Radwan Mohamed
A1  - Koopman, Wouter-Willem Adriaan
A1  - Schuetz, Roman
A1  - Schmid, Thomas
A1  - Liebig, Ferenc
A1  - Koetz, Joachim
A1  - Bargheer, Matias
T1  - The importance of plasmonic heating for the plasmondriven photodimerization of 4-nitrothiophenol
JF  - Scientific Reports
N2  - Metal nanoparticles form potent nanoreactors, driven by the optical generation of energetic electrons and nanoscale heat. The relative influence of these two factors on nanoscale chemistry is strongly debated. This article discusses the temperature dependence of the dimerization of 4-nitrothiophenol (4-NTP) into 4,4′-dimercaptoazobenzene (DMAB) adsorbed on gold nanoflowers by Surface-Enhanced Raman Scattering (SERS). Raman thermometry shows a significant optical heating of the particles. The ratio of the Stokes and the anti-Stokes Raman signal moreover demonstrates that the molecular temperature during the reaction rises beyond the average crystal lattice temperature of the plasmonic particles. The product bands have an even higher temperature than reactant bands, which suggests that the reaction proceeds preferentially at thermal hot spots. In addition, kinetic measurements of the reaction during external heating of the reaction environment yield a considerable rise of the reaction rate with temperature. Despite this significant heating effects, a comparison of SERS spectra recorded after heating the sample by an external heater to spectra recorded after prolonged illumination shows that the reaction is strictly photo-driven. While in both cases the temperature increase is comparable, the dimerization occurs only in the presence of light. Intensity dependent measurements at fixed temperatures confirm this finding.
KW  - enhanced raman-scattering
KW  - charge-transfer
KW  - metal
KW  - nanoparticles
KW  - catalysis
KW  - AU
KW  - 4-nitrobenzenethiol
KW  - aminothiophenol
KW  - photocatalysis
KW  - wavelength
Y1  - 2019
U6  - https://doi.org/10.1038/s41598-019-38627-2
SN  - 2045-2322
VL  - 9
PB  - Macmillan Publishers Limited
CY  - London
ER  - 
TY  - GEN
A1  - Kühne, Katharina
A1  - Fischer, Martin H.
A1  - Zhou, Yuefang
T1  - The Human Takes It All
BT  - Humanlike Synthesized Voices Are Perceived as Less Eerie and More Likable. Evidence From a Subjective Ratings Study
T2  - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe
N2  - Background: The increasing involvement of social robots in human lives raises the question as to how humans perceive social robots. Little is known about human perception of synthesized voices.

Aim: To investigate which synthesized voice parameters predict the speaker's eeriness and voice likability; to determine if individual listener characteristics (e.g., personality, attitude toward robots, age) influence synthesized voice evaluations; and to explore which paralinguistic features subjectively distinguish humans from robots/artificial agents.

Methods: 95 adults (62 females) listened to randomly presented audio-clips of three categories: synthesized (Watson, IBM), humanoid (robot Sophia, Hanson Robotics), and human voices (five clips/category). Voices were rated on intelligibility, prosody, trustworthiness, confidence, enthusiasm, pleasantness, human-likeness, likability, and naturalness. Speakers were rated on appeal, credibility, human-likeness, and eeriness. Participants' personality traits, attitudes to robots, and demographics were obtained.

Results: The human voice and human speaker characteristics received reliably higher scores on all dimensions except for eeriness. Synthesized voice ratings were positively related to participants' agreeableness and neuroticism. Females rated synthesized voices more positively on most dimensions. Surprisingly, interest in social robots and attitudes toward robots played almost no role in voice evaluation. Contrary to the expectations of an uncanny valley, when the ratings of human-likeness for both the voice and the speaker characteristics were higher, they seemed less eerie to the participants. Moreover, when the speaker's voice was more humanlike, it was more liked by the participants. This latter point was only applicable to one of the synthesized voices. Finally, pleasantness and trustworthiness of the synthesized voice predicted the likability of the speaker's voice. Qualitative content analysis identified intonation, sound, emotion, and imageability/embodiment as diagnostic features.

Discussion: Humans clearly prefer human voices, but manipulating diagnostic speech features might increase acceptance of synthesized voices and thereby support human-robot interaction. There is limited evidence that human-likeness of a voice is negatively linked to the perceived eeriness of the speaker.
T3  - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 700 
KW  - human-robot interaction
KW  - paralinguistic features
KW  - synthesized voice
KW  - text-to-speech
KW  - uncanny valley
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-491625
SN  - 1866-8364
IS  - 700
ER  - 
TY  - JOUR
A1  - Kühne, Katharina
A1  - Fischer, Martin H.
A1  - Zhou, Yuefang
T1  - The Human Takes It All
BT  - Humanlike Synthesized Voices Are Perceived as Less Eerie and More Likable. Evidence From a Subjective Ratings Study
JF  - Frontiers in  Neurorobotics
N2  - Background: The increasing involvement of social robots in human lives raises the question as to how humans perceive social robots. Little is known about human perception of synthesized voices.

Aim: To investigate which synthesized voice parameters predict the speaker's eeriness and voice likability; to determine if individual listener characteristics (e.g., personality, attitude toward robots, age) influence synthesized voice evaluations; and to explore which paralinguistic features subjectively distinguish humans from robots/artificial agents.

Methods: 95 adults (62 females) listened to randomly presented audio-clips of three categories: synthesized (Watson, IBM), humanoid (robot Sophia, Hanson Robotics), and human voices (five clips/category). Voices were rated on intelligibility, prosody, trustworthiness, confidence, enthusiasm, pleasantness, human-likeness, likability, and naturalness. Speakers were rated on appeal, credibility, human-likeness, and eeriness. Participants' personality traits, attitudes to robots, and demographics were obtained.

Results: The human voice and human speaker characteristics received reliably higher scores on all dimensions except for eeriness. Synthesized voice ratings were positively related to participants' agreeableness and neuroticism. Females rated synthesized voices more positively on most dimensions. Surprisingly, interest in social robots and attitudes toward robots played almost no role in voice evaluation. Contrary to the expectations of an uncanny valley, when the ratings of human-likeness for both the voice and the speaker characteristics were higher, they seemed less eerie to the participants. Moreover, when the speaker's voice was more humanlike, it was more liked by the participants. This latter point was only applicable to one of the synthesized voices. Finally, pleasantness and trustworthiness of the synthesized voice predicted the likability of the speaker's voice. Qualitative content analysis identified intonation, sound, emotion, and imageability/embodiment as diagnostic features.

Discussion: Humans clearly prefer human voices, but manipulating diagnostic speech features might increase acceptance of synthesized voices and thereby support human-robot interaction. There is limited evidence that human-likeness of a voice is negatively linked to the perceived eeriness of the speaker.
KW  - human-robot interaction
KW  - paralinguistic features
KW  - synthesized voice
KW  - text-to-speech
KW  - uncanny valley
Y1  - 2020
U6  - https://doi.org/10.3389/fnbot.2020.593732
SN  - 1662-5218
VL  - 14
PB  - Frontiers Research Foundation
CY  - Lausanne
ER  - 
TY  - GEN
A1  - Gallego-Llorente, Marcos
A1  - Sarah, Connell
A1  - Jones, Eppie R.
A1  - Merrett, Deborah C.
A1  - Jeon, Y.
A1  - Eriksson, Anders
A1  - Siska, Veronika
A1  - Gamba, Cristina
A1  - Meiklejohn, Christopher
A1  - Beyer, Robert
A1  - Jeon, Sungwon
A1  - Cho, Yun Sung
A1  - Hofreiter, Michael
A1  - Bhak, Jong
A1  - Manica, Andrea
A1  - Pinhasi, Ron
T1  - The genetics of an early Neolithic pastoralist from the Zagros, Iran
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - The agricultural transition profoundly changed human societies. We sequenced and analysed the first genome (1.39x) of an early Neolithic woman from Ganj Dareh, in the Zagros Mountains of Iran, a site with early evidence for an economy based on goat herding, ca. 10,000 BP. We show that Western Iran was inhabited by a population genetically most similar to hunter-gatherers from the Caucasus, but distinct from the Neolithic Anatolian people who later brought food production into Europe. The inhabitants of Ganj Dareh made little direct genetic contribution to modern European populations, suggesting those of the Central Zagros were somewhat isolated from other populations of the Fertile Crescent. Runs of homozygosity are of a similar length to those from Neolithic farmers, and shorter than those of Caucasus and Western Hunter-Gatherers, suggesting that the inhabitants of Ganj Dareh did not undergo the large population bottleneck suffered by their northern neighbours. While some degree of cultural diffusion between Anatolia, Western Iran and other neighbouring regions is possible, the genetic dissimilarity between early Anatolian farmers and the inhabitants of Ganj Dareh supports a model in which Neolithic societies in these areas were distinct.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 952 
KW  - whole-genome association
KW  - ancient
KW  - domestication
KW  - agriculture
KW  - mountains
KW  - diffusion
KW  - migration
KW  - admixture
KW  - patterns
KW  - sequence
KW  - archaeology
KW  - biological anthropology
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-439355
SN  - 1866-8372
IS  - 952
ER  - 
TY  - GEN
A1  - Ceulemans, Ruben
A1  - Gaedke, Ursula
A1  - Klauschies, Toni
A1  - Guill, Christian
T1  - The effects of functional diversity on biomass production, variability, and resilience of ecosystem functions in a tritrophic system
T2  - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe
N2  - Diverse communities can adjust their trait composition to altered environmental conditions, which may strongly influence their dynamics. Previous studies of trait-based models mainly considered only one or two trophic levels, whereas most natural system are at least tritrophic. Therefore, we investigated how the addition of trait variation to each trophic level influences population and community dynamics in a tritrophic model. Examining the phase relationships between species of adjacent trophic levels informs about the strength of top-down or bottom-up control in non-steadystate situations. Phase relationships within a trophic level highlight compensatory dynamical patterns between functionally different species, which are responsible for dampening the community temporal variability. Furthermore, even without trait variation, our tritrophic model always exhibits regions with two alternative states with either weak or strong nutrient exploitation, and correspondingly low or high biomass production at the top level. However, adding trait variation increased the basin of attraction of the high-production state, and decreased the likelihood of a critical transition from the high- to the lowproduction state with no apparent early warning signals. Hence, our study shows that trait variation enhances resource use efficiency, production, stability, and resilience of entire food webs.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 744 
KW  - early-warning signals
KW  - top-down control
KW  - community ecology
KW  - regime shifts
KW  - food webs
KW  - compensatory dynamics
KW  - consumer diversity
KW  - metabolic theory
KW  - rapid evolution
KW  - stable states
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-435439
SN  - 1866-8372
IS  - 744
ER  - 
TY  - JOUR
A1  - Ceulemans, Ruben
A1  - Gaedke, Ursula
A1  - Klauschies, Toni
A1  - Guill, Christian
T1  - The effects of functional diversity on biomass production, variability, and resilience of ecosystem functions in a tritrophic system
JF  - Scientific Reports
N2  - Diverse communities can adjust their trait composition to altered environmental conditions, which may strongly influence their dynamics. Previous studies of trait-based models mainly considered only one or two trophic levels, whereas most natural system are at least tritrophic. Therefore, we investigated how the addition of trait variation to each trophic level influences population and community dynamics in a tritrophic model. Examining the phase relationships between species of adjacent trophic levels informs about the strength of top-down or bottom-up control in non-steadystate situations. Phase relationships within a trophic level highlight compensatory dynamical patterns between functionally different species, which are responsible for dampening the community temporal variability. Furthermore, even without trait variation, our tritrophic model always exhibits regions with two alternative states with either weak or strong nutrient exploitation, and correspondingly low or high biomass production at the top level. However, adding trait variation increased the basin of attraction of the high-production state, and decreased the likelihood of a critical transition from the high- to the lowproduction state with no apparent early warning signals. Hence, our study shows that trait variation enhances resource use efficiency, production, stability, and resilience of entire food webs.
KW  - early-warning signals
KW  - top-down control
KW  - community ecology
KW  - regime shifts
KW  - food webs
KW  - compensatory dynamics
KW  - consumer diversity
KW  - metabolic theory
KW  - rapid evolution
KW  - stable states
Y1  - 2019
U6  - https://doi.org/10.1038/s41598-019-43974-1
SN  - 2045-2322
VL  - 9
PB  - Macmillan Publishers Limited
CY  - London
ER  - 
TY  - THES
A1  - Harbart, Vanessa
T1  - The effect of protected cultivation on the nutritional quality of lettuce (Lactuca sativa var capitata L.) with a focus on antifogging additives in polyolefin covers
T1  - Die Bedeutung des geschützten Anbaus für die ernährungsphysiologische Qualität von Kopfsalat (Lactuca sativa var. capitata L.) mit Schwerpunkt auf Antibeschlagmittel in Polyolefinfolien
N2  - Protected cultivation in greenhouses or polytunnels offers the potential for sustainable production of high-yield, high-quality vegetables. This is related to the ability to produce more on less land and to use resources responsibly and efficiently. Crop yield has long been considered the most important factor. However, as plant-based diets have been proposed for a sustainable food system, the targeted enrichment of health-promoting plant secondary metabolites should be addressed. These metabolites include carotenoids and flavonoids, which are associated with several health benefits, such as cardiovascular health and cancer protection. 
Cover materials generally have an influence on the climatic conditions, which in turn can affect the levels of secondary metabolites in vegetables grown underneath. Plastic materials are cost-effective and their properties can be modified by incorporating additives, making them the first choice. However, these additives can migrate and leach from the material, resulting in reduced service life, increased waste and possible environmental release. Antifogging additives are used in agricultural films to prevent the formation of droplets on the film surface, thereby increasing light transmission and preventing microbiological contamination. 
This thesis focuses on LDPE/EVA covers and incorporated antifogging additives for sustainable protected cultivation, following two different approaches. The first addressed the direct effects of leached antifogging additives using simulation studies on lettuce leaves (Lactuca sativa var capitata L). The second determined the effect of antifog polytunnel covers on lettuce quality. Lettuce is usually grown under protective cover and can provide high nutritional value due to its carotenoid and flavonoid content, depending on the cultivar. 
To study the influence of simulated leached antifogging additives on lettuce leaves, a GC-MS method was first developed to analyze these additives based on their fatty acid moieties. Three structurally different antifogging additives (reference material) were characterized outside of a polymer matrix for the first time. All of them contained more than the main fatty acid specified by the manufacturer. Furthermore, they were found to adhere to the leaf surface and could not be removed by water or partially by hexane. 
The incorporation of these additives into polytunnel covers affects carotenoid levels in lettuce, but not flavonoids, caffeic acid derivatives and chlorophylls. Specifically, carotenoids were higher in lettuce grown under polytunnels without antifog than with antifog. This has been linked to their effect on the light regime and was suggested to be related to carotenoid function in photosynthesis. 
In terms of protected cultivation, the use of LDPE/EVA polytunnels affected light and temperature, and both are closely related. The carotenoid and flavonoid contents of lettuce grown under polytunnels was reversed, with higher carotenoid and lower flavonoid levels. At the individual level, the flavonoids detected in lettuce did not differ however, lettuce carotenoids adapted specifically depending on the time of cultivation. Flavonoid reduction was shown to be transcriptionally regulated (CHS) in response to UV light (UVR8). In contrast, carotenoids are thought to be regulated post-transcriptionally, as indicated by the lack of correlation between carotenoid levels and transcripts of the first enzyme in carotenoid biosynthesis (PSY) and a carotenoid degrading enzyme (CCD4), as well as the increased carotenoid metabolic flux. Understanding the regulatory mechanisms and metabolite adaptation strategies could further advance the strategic development and selection of cover materials.
N2  - Der geschützte Anbau in Gewächshäusern oder unter Folientunneln bietet die Möglichkeit einer nachhaltigen Produktion von ertragreichem Gemüse hoher Qualität. Die ressourceneffiziente Produktion von mehr auf weniger Fläche ist dabei ein wichtiger Faktor. Lange galt der Gemüseertrag als wichtigstes Kriterium. Die Anreicherung von gesundheitsfördernden sekundären Pflanzenmetaboliten gewinnt jedoch zunehmend an Bedeutung, nicht zuletzt durch die empfohlene pflanzenbasierte Ernährung für ein nachhaltiges Ernährungssystem. Die Sekundärmetabolite Carotinoide und Flavonoide sind mit verschiedenen gesundheitlichen Vorteilen assoziiert, etwa der kardiovaskulären Gesundheit und der Krebsprävention. 
Das Material eines Gewächshauses beeinflusst die klimatischen Bedingungen im geschützten Anbau. Das resultierende Mikroklima kann sich wiederum auf den Gehalt an Sekundärmetaboliten im Gemüse auswirken. Materialien aus Kunststoff sind kostengünstig und ihre Eigenschaften können durch Zusätze, sogenannte Additive, modifiziert werden. Additive können an die Oberfläche des Materials und aus diesem migrieren, was die Materiallebensdauer einerseits verkürzt und größere Abfallmengen produziert. Andererseits besteht das Risiko einer Umweltemission der Additive. Antifogging-Additive verhindern die Bildung von Kondenswasser Tropfen auf der Oberfläche von Gewächshausfolien, wodurch die Lichtdurchlässigkeit der Folien verbessert, sowie eine mikrobiologische Kontamination vermieden werden kann. 
Die vorliegende Arbeit befasst sich mit LDPE/EVA-Gewächshausfolien mit Antifogging-Additiven für einen nachhaltigen geschützten Anbau und verfolgt dabei zwei unterschiedliche Herangehensweisen. Zum einen befasst sich die Arbeit mit den direkten Auswirkungen von Antifogging-Additiven in Folge eines Übergangs auf Salatblätter (Lactuca sativa var. capitata L.) mittels Simulationsversuchen. Um den simulierten Übergang zu untersuchen, wurde zunächst eine Methode zur Analyse des Fettsäureanteils der Additive mittels GC-MS entwickelt. Drei strukturell unterschiedliche Antifogging-Additive (Referenzmaterial) wurden erstmals außerhalb einer Polymermatrix charakterisiert. Sie enthielten diverse Fettsäuren, und somit mehr, als die vom Hersteller angegebene Hauptfettsäure. Des Weiteren wurde gezeigt, dass sie an der Blattoberfläche haften und weder durch Wasser noch teilweise durch Hexan entfernt werden können.
Zum anderen wurde der Einfluss von Antifogging-Additiven in Gewächshausfolien auf die Salatqualität untersucht. Salat ist ein Gemüse, das üblicherweise auch unter Schutzabdeckungen angebaut wird und sortenspezifisch größere Mengen an Carotinoiden und Flavonoiden enthält. Der Anbau von Salat unter Antifog-Folientunneln beeinflusste den Carotinoidgehalt, nicht aber den Gehalt an Flavonoiden, Kaffeesäurederivaten und Chlorophyll. Salate, die unter Folientunneln ohne Antifog angebaut wurde akkumulierten höhere Gehalte der Carotinoide, als solche unter Antifog-Folientunneln. Es besteht wahrscheinlich ein Zusammenhang mit der Funktion der Carotinoide als Photosynthesepigmente und der Lichtumgebung. Die Verwendung von LDPE/EVA-Folientunneln beeinflusste allgemein Licht und Temperatur im geschützten Anbau, beide Faktoren sind eng verknüpft. Die Carotinoid- und Flavonoidgehalte waren dabei invers, mit höheren gesamt Carotinoid- und niedrigeren gesamt Flavonoidgehalten von Salaten unter Folientunneln. Die individuellen Flavonoid-Glykoside unterschieden sich innerhalb der Versuchszeiträume (Frühjahr und Herbst) nicht. Es konnte gezeigt werden, dass diese hinsichtlich der UV-Lichtumgebung (UVR8) transkriptionell reguliert werden (CHS). Demgegenüber fanden spezifische Anpassungen der individuellen Carotinoidmetabolite in den Versuchszeiträumen statt. Die fehlende Korrelation der Carotinoidmetabolite und der Transkripte des Hauptenzyms der Biosynthese (PSY) und eines Carotinoid-abbauenden Enzyms (CCD4) sowie der erhöhte Carotinoid-Stoffwechselfluss deuten auf eine post-transkriptionelle Regulierung hin. 
Die Regulationsmechanismen und Anpassungsstrategien der sekundären Pflanzenstoffe in Gemüse zu verstehen, könnte zukünftig zur strategischen Entwicklung und Auswahl von Gewächshausmaterialien beitragen.
KW  - protected cultivation
KW  - polytunnel
KW  - lettuce
KW  - antifogging additives
KW  - plant secondary metabolites
KW  - carotenoids
KW  - flavonoids
KW  - mass spectrometry
KW  - plastic additives
KW  - Antibeschlag-Additive
KW  - Carotinoide
KW  - Flavonoide
KW  - Kopfsalat
KW  - Massenspektrometrie
KW  - sekundäre Pflanzenstoffe
KW  - Kunststoff-Additive
KW  - Folientunnel
KW  - geschützter Anbau
Y1  - 2024
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-629375
ER  - 
TY  - GEN
A1  - Epp, Laura Saskia
A1  - Kruse, Stefan
A1  - Kath, Nadja J.
A1  - Stoof-Leichsenring, Kathleen Rosemarie
A1  - Tiedemann, Ralph
A1  - Pestryakova, Luidmila Agafyevna
A1  - Herzschuh, Ulrike
T1  - Temporal and spatial patterns of mitochondrial haplotype and species distributions in Siberian larches inferred from ancient environmental DNA and modeling
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - Changes in species' distributions are classically projected based on their climate envelopes. For Siberian forests, which have a tremendous significance for vegetation-climate feedbacks, this implies future shifts of each of the forest-forming larch (Larix) species to the north-east. However, in addition to abiotic factors, reliable projections must assess the role of historical biogeography and biotic interactions. Here, we use sedimentary ancient DNA and individual-based modelling to investigate the distribution of larch species and mitochondrial haplotypes through space and time across the treeline ecotone on the southern Taymyr peninsula, which at the same time presents a boundary area of two larch species. We find spatial and temporal patterns, which suggest that forest density is the most influential driver determining the precise distribution of species and mitochondrial haplotypes. This suggests a strong influence of competition on the species' range shifts. These findings imply possible climate change outcomes that are directly opposed to projections based purely on climate envelopes. Investigations of such fine-scale processes of biodiversity change through time are possible using paleoenvironmental DNA, which is available much more readily than visible fossils and can provide information at a level of resolution that is not reached in classical palaeoecology.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1052 
KW  - ecological genetics
KW  - ecological modelling
KW  - palaeoecology
KW  - plant ecology
KW  - climate change
KW  - introgression
KW  - temperature
KW  - treeline
KW  - vegetation
KW  - mitochondrial haplotypes
KW  - Siberian larch
KW  - larch species
KW  - range shifts
KW  - vegetation-climate feedbacks
KW  - ecosystems
KW  - impacts
KW  - dynamics
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-468352
SN  - 1866-8372
IS  - 1052
ER  - 
TY  - GEN
A1  - Jiang, Yi
A1  - Mansfeld, Ulrich
A1  - Fang, Liang
A1  - Kratz, Karl
A1  - Lendlein, Andreas
T1  - Temperature-induced evolution of microstructures on poly[ethylene-co-(vinyl acetate)] substrates switches their underwater wettability
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - Material surfaces with tailored aerophobicity are crucial for applications where gas bubble wettability has to be controlled, e.g., gas storage and transport, electrodes, bioreactors or medical devices.

Here, we present switchable underwater aerophobicity of hydrophobic polymeric substrates, which respond to heat with multilevel micro- and nanotopographical changes. The cross-linked poly[ethylene-co-(vinyl acetate)] substrates possess arrays of microcylinders with a nanorough top surface. It is hypothesized that the specific micro-/nanotopography of the surface allows trapping of a water film at the micro interspace and in this way generates the aerophobic behavior. The structured substrates were programmed to a temporarily stable, nanoscale flat substrate showing aerophilic behavior. Upon heating, the topographical changes caused a switch in contact angle from aerophilic to aerophobic for approaching air bubbles. In this way, the initial adhesion of air bubbles to the programmed flat substrate could be turned into repellence for the recovered substrate surface. The temperature at which the repellence of air bubbles starts can be adjusted from 58 ± 3 °C to 73 ± 3 °C by varying the deformation temperature applied during the temperature-memory programming procedure. The presented actively switching polymeric substrates are attractive candidates for applications, where an on-demand gas bubble repellence is advantageous.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 639 
KW  - aerophobicity
KW  - temperature-memory effect
KW  - switchable wettability
KW  - air bubble repellence
KW  - thermo-responsive polymer
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-424601
SN  - 1866-8372
IS  - 639
ER  - 
TY  - JOUR
A1  - Paraskevopoulou, Sofia
A1  - Dennis, Alice B.
A1  - Weithoff, Guntram
A1  - Tiedemann, Ralph
T1  - Temperature-dependent life history and transcriptomic responses in heat-tolerant versus heat-sensitive Brachionus rotifers
JF  - Scientific Reports
N2  - Thermal stress response is an essential physiological trait that determines occurrence and temporal succession in nature, including response to climate change. We compared temperature-related demography in closely related heat-tolerant and heat-sensitive Brachionus rotifer species. We found significant differences in heat response, with the heat-sensitive species adopting a strategy of long survival and low population growth, while the heat-tolerant followed the opposite strategy. In both species, we examined the genetic basis of physiological variation by comparing gene expression across increasing temperatures. Comparative transcriptomic analyses identified shared and opposing responses to heat. Interestingly, expression of heat shock proteins (hsps) was strikingly different in the two species and mirrored differences in population growth rates, showing that hsp genes are likely a key component of a species’ adaptation to different temperatures. Temperature induction caused opposing patterns of expression in further functional categories including energy, carbohydrate and lipid metabolism, and in genes related to ribosomal proteins. In the heat-sensitive species, elevated temperatures caused up-regulation of genes related to meiosis induction and post-translational histone modifications. This work demonstrates the sweeping reorganizations of biological functions that accompany temperature adaptation in these two species and reveals potential molecular mechanisms that might be activated for adaptation to global warming.
KW  - Ecology
KW  - Evolution
KW  - Oyster Crassostrea-gigas
KW  - cryptic species complex
KW  - pacific oyster
KW  - thermal-stress
KW  - genetic differentiation
KW  - expression patterns
KW  - molecular phylogeny
KW  - shock proteins
KW  - evolutionary
KW  - hsp70
Y1  - 2020
U6  - https://doi.org/10.1038/s41598-020-70173-0
SN  - 2045-2322
VL  - 10
PB  - Macmillan Publishers Limited, part of Springer Nature
CY  - London
ER  - 
TY  - GEN
A1  - Paraskevopoulou, Sofia
A1  - Dennis, Alice B.
A1  - Weithoff, Guntram
A1  - Tiedemann, Ralph
T1  - Temperature-dependent life history and transcriptomic responses in heat-tolerant versus heat-sensitive Brachionus rotifers
T2  - Postprints der Universität Potsdam : Mathematisch Naturwissenschaftliche Reihe
N2  - Thermal stress response is an essential physiological trait that determines occurrence and temporal succession in nature, including response to climate change. We compared temperature-related demography in closely related heat-tolerant and heat-sensitive Brachionus rotifer species. We found significant differences in heat response, with the heat-sensitive species adopting a strategy of long survival and low population growth, while the heat-tolerant followed the opposite strategy. In both species, we examined the genetic basis of physiological variation by comparing gene expression across increasing temperatures. Comparative transcriptomic analyses identified shared and opposing responses to heat. Interestingly, expression of heat shock proteins (hsps) was strikingly different in the two species and mirrored differences in population growth rates, showing that hsp genes are likely a key component of a species’ adaptation to different temperatures. Temperature induction caused opposing patterns of expression in further functional categories including energy, carbohydrate and lipid metabolism, and in genes related to ribosomal proteins. In the heat-sensitive species, elevated temperatures caused up-regulation of genes related to meiosis induction and post-translational histone modifications. This work demonstrates the sweeping reorganizations of biological functions that accompany temperature adaptation in these two species and reveals potential molecular mechanisms that might be activated for adaptation to global warming.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1012 
KW  - Ecology
KW  - Evolution
KW  - Oyster Crassostrea-gigas
KW  - cryptic species complex
KW  - pacific oyster
KW  - thermal-stress
KW  - genetic differentiation
KW  - expression patterns
KW  - molecular phylogeny
KW  - shock proteins
KW  - evolutionary
KW  - hsp70
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-482280
SN  - 1866-8372
IS  - 1012
ER  - 
TY  - GEN
A1  - Pauly, Maren
A1  - Helle, Gerhard
A1  - Miramont, Cécile
A1  - Büntgen, Ulf
A1  - Treydte, Kerstin
A1  - Reinig, Frederick
A1  - Guibal, Frédéric
A1  - Sivan, Olivier
A1  - Heinrich, Ingo
A1  - Riedel, Frank
A1  - Kromer, Bernd
A1  - Balanzategui, Daniel
A1  - Wacker, Lukas
A1  - Sookdeo, Adam Sookdeo
A1  - Brauer, Achim
T1  - Subfossil trees suggest enhanced Mediterranean hydroclimate variability at the onset of the Younger Dryas
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - Nearly 13,000 years ago, the warming trend into the Holocene was sharply interrupted by a reversal to near glacial conditions. Climatic causes and ecological consequences of the Younger Dryas (YD) have been extensively studied, however proxy archives from the Mediterranean basin capturing this period are scarce and do not provide annual resolution. Here, we report a hydroclimatic reconstruction from stable isotopes (delta O-18, delta C-13) in subfossil pines from southern France. Growing before and during the transition period into the YD (12 900-12 600 cal BP), the trees provide an annually resolved, continuous sequence of atmospheric change. Isotopic signature of tree sourcewater (delta O-18(sw)) and estimates of relative air humidity were reconstructed as a proxy for variations in air mass origin and precipitation regime. We find a distinct increase in inter-annual variability of sourcewater isotopes (delta O-18(sw)), with three major downturn phases of increasing magnitude beginning at 12 740 cal BP. The observed variation most likely results from an amplified intensity of North Atlantic (low delta O-18(sw)) versus Mediterranean (high delta O-18(sw)) precipitation. This marked pattern of climate variability is not seen in records from higher latitudes and is likely a consequence of atmospheric circulation oscillations at the margin of the southward moving polar front.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1135 
KW  - annually laminated sediments
KW  - lake Meerfelder Maar
KW  - isotopic composition
KW  - oxygen isotope
KW  - climate
KW  - cellulose
KW  - radiocarbon
KW  - temperature
KW  - record
KW  - model
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-459169
SN  - 1866-8372
IS  - 1135
ER  - 
TY  - GEN
A1  - Biterova, Ekaterina
A1  - Esmaeeli Moghaddam Tabalvandani, Mariam
A1  - Alanen, Heli I.
A1  - Saaranen, Mirva
A1  - Ruddock, Lloyd W.
T1  - Structures of Angptl3 and Angptl4
BT  - modulators of triglyceride levels and coronary artery disease
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - Coronary artery disease is the most common cause of death globally and is linked to a number of risk factors including serum low density lipoprotein, high density lipoprotein, triglycerides and lipoprotein(a). Recently two proteins, angiopoietin-like protein 3 and 4, have emerged from genetic studies as being factors that significantly modulate plasma triglyceride levels and coronary artery disease. The exact function and mechanism of action of both proteins remains to be elucidated, however, mutations in these proteins results in up to 34% reduction in coronary artery disease and inhibition of function results in reduced plasma triglyceride levels. Here we report the crystal structures of the fibrinogen-like domains of both proteins. These structures offer new insights into the reported loss of function mutations, the mechanisms of action of the proteins and open up the possibility for the rational design of low molecular weight inhibitors for intervention in coronary artery disease.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1048 
KW  - angiopoitin-like 4
KW  - of-function mutations
KW  - cardiovascular-disease
KW  - lipoprotein-lipase
KW  - heart-disease
KW  - risk
KW  - recognition
KW  - protein
KW  - metaanalysis
KW  - association
KW  - cardiovascular biology
KW  - x-ray crystallography
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-467943
SN  - 1866-8372
IS  - 1048
ER  - 
TY  - JOUR
A1  - Léonard, Fabien
A1  - Zhang, Zhen
A1  - Krebs, Holger
A1  - Bruno, Giovanni
T1  - Structural and morphological quantitative 3D characterisation of ammonium nitrate prills by X-ray computed tomography
JF  - Materials
N2  - The mixture of ammonium nitrate (AN) prills and fuel oil (FO), usually referred to as ANFO, is extensively used in the mining industry as a bulk explosive. One of the major performance predictors of ANFO mixtures is the fuel oil retention, which is itself governed by the complex pore structure of the AN prills. In this study, we present how X-ray computed tomography (XCT), and the associated advanced data processing workflow, can be used to fully characterise the structure and morphology of AN prills. We show that structural parameters such as volume fraction of the different phases and morphological parameters such as specific surface area and shape factor can be reliably extracted from the XCT data, and that there is a good agreement with the measured oil retention values. Importantly, oil retention measurements (qualifying the efficiency of ANFO as explosives) correlate well with the specific surface area determined by XCT. XCT can therefore be employed non-destructively; it can accurately evaluate and characterise porosity in ammonium nitrate prills, and even predict their efficiency.
KW  - ANFO
KW  - explosives
KW  - specific surface area
KW  - porosity
KW  - XCT
KW  - data processing
Y1  - 2020
U6  - https://doi.org/10.3390/ma13051230
SN  - 1996-1944
VL  - 13
IS  - 5
PB  - MDPI
CY  - Basel
ER  - 
TY  - GEN
A1  - Senczuk, Gabriele
A1  - Havenstein, Katja
A1  - Milana, Valentina
A1  - Ripa, Chiara
A1  - De Simone, Emanuela
A1  - Tiedemann, Ralph
A1  - Castiglia, Riccardo
T1  - Spotlight on islands
BT  - on the origin and diversification of an ancient lineage of the Italian wall lizard Podarcis siculus in the western Pontine Islands
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - Groups of proximate continental islands may conceal more tangled phylogeographic patterns than oceanic archipelagos as a consequence of repeated sea level changes, which allow populations to experience gene flow during periods of low sea level stands and isolation by vicariant mechanisms during periods of high sea level stands. Here, we describe for the first time an ancient and diverging lineage of the Italian wall lizard Podarcis siculus from the western Pontine Islands. We used nuclear and mitochondrial DNA sequences of 156 individuals with the aim of unraveling their phylogenetic position, while microsatellite loci were used to test several a priori insular biogeographic models of migration with empirical data. Our results suggest that the western Pontine populations colonized the islands early during their Pliocene volcanic formation, while populations from the eastern Pontine Islands seem to have been introduced recently. The inter-island genetic makeup indicates an important role of historical migration, probably due to glacial land bridges connecting islands followed by a recent vicariant mechanism of isolation. Moreover, the most supported migration model predicted higher gene flow among islands which are geographically arranged in parallel. Considering the threatened status of small insular endemic populations, we suggest this new evolutionarily independent unit be given priority in conservation efforts.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 991 
KW  - mitochondrial dna sequences
KW  - genetic diversity
KW  - haplotype reconstruction
KW  - evolutionary history
KW  - geological evolution
KW  - population structure
KW  - Tyrrhenian Sea
KW  - endemic lizard
KW  - genotype data
KW  - biogeography
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-446360
SN  - 1866-8372
IS  - 991
ER  - 
TY  - GEN
A1  - Crawford, Tim
A1  - Karamat, Fazeelat
A1  - Lehotai, Nóra
A1  - Rentoft, Matilda
A1  - Blomberg, Jeanette
A1  - Strand, Åsa
A1  - Björklund, Stefan
T1  - Specific functions for mediator complex subunits from different modules in the transcriptional response of arabidopsis thaliana to abiotic stress
T2  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - Adverse environmental conditions are detrimental to plant growth and development. Acclimation to abiotic stress conditions involves activation of signaling pathways which often results in changes in gene expression via networks of transcription factors (TFs). Mediator is a highly conserved co-regulator complex and an essential component of the transcriptional machinery in eukaryotes. Some Mediator subunits have been implicated in stress-responsive signaling pathways; however, much remains unknown regarding the role of plant Mediator in abiotic stress responses. Here, we use RNA-seq to analyze the transcriptional response of Arabidopsis thaliana to heat, cold and salt stress conditions. We identify a set of common abiotic stress regulons and describe the sequential and combinatorial nature of TFs involved in their transcriptional regulation. Furthermore, we identify stress-specific roles for the Mediator subunits MED9, MED16, MED18 and CDK8, and putative TFs connecting them to different stress signaling pathways. Our data also indicate different modes of action for subunits or modules of Mediator at the same gene loci, including a co-repressor function for MED16 prior to stress. These results illuminate a poorly understood but important player in the transcriptional response of plants to abiotic stress and identify target genes and mechanisms as a prelude to further biochemical characterization.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1399 
KW  - regulate gene expression
KW  - signal transduction
KW  - circadian clock
KW  - plant Mediator
KW  - salicylic-acid
KW  - activation
KW  - jasmonate
KW  - network
KW  - defense
KW  - MED16
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-513666
SN  - 1866-8372
IS  - 1
ER  - 
TY  - JOUR
A1  - Crawford, Tim
A1  - Karamat, Fazeelat
A1  - Lehotai, Nóra
A1  - Rentoft, Matilda
A1  - Blomberg, Jeanette
A1  - Strand, Åsa
A1  - Björklund, Stefan
T1  - Specific functions for mediator complex subunits from different modules in the transcriptional response of arabidopsis thaliana to abiotic stress
JF  - Scientific reports
N2  - Adverse environmental conditions are detrimental to plant growth and development. Acclimation to abiotic stress conditions involves activation of signaling pathways which often results in changes in gene expression via networks of transcription factors (TFs). Mediator is a highly conserved co-regulator complex and an essential component of the transcriptional machinery in eukaryotes. Some Mediator subunits have been implicated in stress-responsive signaling pathways; however, much remains unknown regarding the role of plant Mediator in abiotic stress responses. Here, we use RNA-seq to analyze the transcriptional response of Arabidopsis thaliana to heat, cold and salt stress conditions. We identify a set of common abiotic stress regulons and describe the sequential and combinatorial nature of TFs involved in their transcriptional regulation. Furthermore, we identify stress-specific roles for the Mediator subunits MED9, MED16, MED18 and CDK8, and putative TFs connecting them to different stress signaling pathways. Our data also indicate different modes of action for subunits or modules of Mediator at the same gene loci, including a co-repressor function for MED16 prior to stress. These results illuminate a poorly understood but important player in the transcriptional response of plants to abiotic stress and identify target genes and mechanisms as a prelude to further biochemical characterization.
KW  - regulate gene expression
KW  - signal transduction
KW  - circadian clock
KW  - plant Mediator
KW  - salicylic-acid
KW  - activation
KW  - jasmonate
KW  - network
KW  - defense
KW  - MED16
Y1  - 2020
U6  - https://doi.org/10.1038/s41598-020-61758-w
SN  - 2045-2322
VL  - 10
IS  - 1
SP  - 1
EP  - 18
PB  - Macmillan Publishers Limited, part of Springer Nature
CY  - London
ER  - 
TY  - GEN
A1  - Lemaire, Olivier N.
A1  - Infossi, Pascale
A1  - Chaouche, Amine Ali
A1  - Espinosa, Leon
A1  - Leimkühler, Silke
A1  - Giudici-Orticoni, Marie-Thérèse
A1  - Méjean, Vincent
A1  - Iobbi-Nivol, Chantal
T1  - Small membranous proteins of the TorE/NapE family, crutches for cognate respiratory systems in Proteobacteria
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - In this report, we investigate small proteins involved in bacterial alternative respiratory systems that improve the enzymatic efficiency through better anchorage and multimerization of membrane components. Using the small protein TorE of the respiratory TMAO reductase system as a model, we discovered that TorE is part of a subfamily of small proteins that are present in proteobacteria in which they play a similar role for bacterial respiratory systems. We reveal by microscopy that, in Shewanella oneidensis MR1, alternative respiratory systems are evenly distributed in the membrane contrary to what has been described for Escherichia coli. Thus, the better efficiency of the respiratory systems observed in the presence of the small proteins is not due to a specific localization in the membrane, but rather to the formation of membranous complexes formed by TorE homologs with their c-type cytochrome partner protein. By an in vivo approach combining Clear Native electrophoresis and fluorescent translational fusions, we determined the 4: 4 stoichiometry of the complexes. In addition, mild solubilization of the cytochrome indicates that the presence of the small protein reinforces its anchoring to the membrane. Therefore, assembly of the complex induced by this small protein improves the efficiency of the respiratory system.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 933 
KW  - trimethylamine n-oxide
KW  - molybdenum cofactor biosynthesis
KW  - cytochrome bd oxidase
KW  - c-type cytochromes
KW  - escherichia-coli
KW  - swiss-model
KW  - native electrophoresis
KW  - mutational analysis
KW  - reductase
KW  - nitrate
KW  - microbiology
KW  - microbiology techniques
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-459208
SN  - 1866-8372
IS  - 933
ER  - 
TY  - JOUR
A1  - Lemaire, Olivier N.
A1  - Infossi, Pascale
A1  - Chaouche, Amine Ali
A1  - Espinosa, Leon
A1  - Leimkühler, Silke
A1  - Giudici-Orticoni, Marie-Therese
A1  - Mejean, Vincent
A1  - Iobbi-Nivol, Chantal
T1  - Small membranous proteins of the TorE/NapE family, crutches for cognate respiratory systems in Proteobacteria
JF  - Scientific reports
N2  - In this report, we investigate small proteins involved in bacterial alternative respiratory systems that improve the enzymatic efficiency through better anchorage and multimerization of membrane components. Using the small protein TorE of the respiratory TMAO reductase system as a model, we discovered that TorE is part of a subfamily of small proteins that are present in proteobacteria in which they play a similar role for bacterial respiratory systems. We reveal by microscopy that, in Shewanella oneidensis MR1, alternative respiratory systems are evenly distributed in the membrane contrary to what has been described for Escherichia coli. Thus, the better efficiency of the respiratory systems observed in the presence of the small proteins is not due to a specific localization in the membrane, but rather to the formation of membranous complexes formed by TorE homologs with their c-type cytochrome partner protein. By an in vivo approach combining Clear Native electrophoresis and fluorescent translational fusions, we determined the 4: 4 stoichiometry of the complexes. In addition, mild solubilization of the cytochrome indicates that the presence of the small protein reinforces its anchoring to the membrane. Therefore, assembly of the complex induced by this small protein improves the efficiency of the respiratory system.
Y1  - 2018
U6  - https://doi.org/10.1038/s41598-018-31851-2
SN  - 2045-2322
VL  - 8
PB  - Nature Publ. Group
CY  - London
ER  - 
TY  - GEN
A1  - Omori, Toshihiro
A1  - Winter, Katja
A1  - Shinohara, Kyosuke
A1  - Hamada, Hiroshi
A1  - Ishikawa, Takuji
T1  - Simulation of the nodal flow of mutant embryos with a small number of cilia
BT  - comparison of mechanosensing and vesicle transport hypotheses
T2  - Postprints der Universität Potsdam : Mathematisch Naturwissenschaftliche Reihe
N2  - Left-right (L-R) asymmetry in the body plan is determined by nodal flow in vertebrate embryos. Shinohara et al. (Shinohara K et al. 2012 Nat. Commun. 3, 622 (doi:10.1038/ncomms1624)) used Dpcd and Rfx3 mutant mouse embryos and showed that only a few cilia were sufficient to achieve L-R asymmetry. However, the mechanism underlying the breaking of symmetry by such weak ciliary flow is unclear. Flow-mediated signals associated with the L-R asymmetric organogenesis have not been clarified, and two different hypotheses-vesicle transport and mechanosensing-are now debated in the research field of developmental biology. In this study, we developed a computational model of the node system reported by Shinohara et al. and examined the feasibilities of the two hypotheses with a small number of cilia. With the small number of rotating cilia, flow was induced locally and global strong flow was not observed in the node. Particles were then effectively transported only when they were close to the cilia, and particle transport was strongly dependent on the ciliary positions. Although the maximum wall shear rate was also influenced by ciliary position, the mean wall shear rate at the perinodal wall increased monotonically with the number of cilia. We also investigated the membrane tension of immotile cilia, which is relevant to the regulation of mechanotransduction. The results indicated that tension of about 0.1 mu Nm(-1) was exerted at the base even when the fluid shear rate was applied at about 0.1 s(-1). The area of high tension was also localized at the upstream side, and negative tension appeared at the downstream side. Such localization may be useful to sense the flow direction at the periphery, as time-averaged anticlockwise circulation was induced in the node by rotation of a few cilia. Our numerical results support the mechanosensing hypothesis, and we expect that our study will stimulate further experimental investigations of mechanotransduction in the near future.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1056 
KW  - nodal flow
KW  - left-right asymmetry
KW  - boundary element method
KW  - fluid-structure interaction
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-468734
SN  - 1866-8372
IS  - 1056
ER  - 
TY  - JOUR
A1  - Omori, Toshihiro
A1  - Winter, Katja
A1  - Shinohara, Kyosuke
A1  - Hamada, Hiroshi
A1  - Ishikawa, Takuji
T1  - Simulation of the nodal flow of mutant embryos with a small number of cilia
BT  - comparison of mechanosensing and vesicle transport hypotheses
JF  - Royal Society Open Science
N2  - Left-right (L-R) asymmetry in the body plan is determined by nodal flow in vertebrate embryos. Shinohara et al. (Shinohara K et al. 2012 Nat. Commun. 3, 622 (doi:10.1038/ncomms1624)) used Dpcd and Rfx3 mutant mouse embryos and showed that only a few cilia were sufficient to achieve L-R asymmetry. However, the mechanism underlying the breaking of symmetry by such weak ciliary flow is unclear. Flow-mediated signals associated with the L-R asymmetric organogenesis have not been clarified, and two different hypotheses-vesicle transport and mechanosensing-are now debated in the research field of developmental biology. In this study, we developed a computational model of the node system reported by Shinohara et al. and examined the feasibilities of the two hypotheses with a small number of cilia. With the small number of rotating cilia, flow was induced locally and global strong flow was not observed in the node. Particles were then effectively transported only when they were close to the cilia, and particle transport was strongly dependent on the ciliary positions. Although the maximum wall shear rate was also influenced by ciliary position, the mean wall shear rate at the perinodal wall increased monotonically with the number of cilia. We also investigated the membrane tension of immotile cilia, which is relevant to the regulation of mechanotransduction. The results indicated that tension of about 0.1 mu Nm(-1) was exerted at the base even when the fluid shear rate was applied at about 0.1 s(-1). The area of high tension was also localized at the upstream side, and negative tension appeared at the downstream side. Such localization may be useful to sense the flow direction at the periphery, as time-averaged anticlockwise circulation was induced in the node by rotation of a few cilia. Our numerical results support the mechanosensing hypothesis, and we expect that our study will stimulate further experimental investigations of mechanotransduction in the near future.
KW  - nodal flow
KW  - left-right asymmetry
KW  - boundary element method
KW  - fluid-structure interaction
Y1  - 2018
U6  - https://doi.org/10.1098/rsos.180601
SN  - 2054-5703
VL  - 5
IS  - 8
PB  - Royal Society
CY  - London
ER  - 
TY  - JOUR
A1  - Schaller, Jörg
A1  - Scherwietes, Eric
A1  - Gerber, Lukas
A1  - Vaidya, Shrijana
A1  - Kaczorek, Danuta
A1  - Pausch, Johanna
A1  - Barkusky, Dietmar
A1  - Sommer, Michael
A1  - Hoffmann, Mathias
T1  - Silica fertilization improved wheat performance and increased phosphorus concentrations during drought at the field scale
JF  - Scientific reports
N2  - Drought and the availability of mineable phosphorus minerals used for fertilization are two of the important issues agriculture is facing in the future. High phosphorus availability in soils is necessary to maintain high agricultural yields. Drought is one of the major threats for terrestrial ecosystem performance and crop production in future. Among the measures proposed to cope with the upcoming challenges of intensifying drought stress and to decrease the need for phosphorus fertilizer application is the fertilization with silica (Si). Here we tested the importance of soil Si fertilization on wheat phosphorus concentration as well as wheat performance during drought at the field scale. Our data clearly showed a higher soil moisture for the Si fertilized plots. This higher soil moisture contributes to a better plant performance in terms of higher photosynthetic activity and later senescence as well as faster stomata responses ensuring higher productivity during drought periods. The plant phosphorus concentration was also higher in Si fertilized compared to control plots. Overall, Si fertilization or management of the soil Si pools seem to be a promising tool to maintain crop production under predicted longer and more serve droughts in the future and reduces phosphorus fertilizer requirements.
Y1  - 2021
U6  - https://doi.org/10.1038/s41598-021-00464-7
SN  - 2045-2322
VL  - 11
IS  - 1
PB  - Macmillan Publishers Limited, part of Springer Nature
CY  - [London]
ER  - 
TY  - GEN
A1  - Sperber, Hannah Sabeth
A1  - Welke, Robert-William
A1  - Petazzi, Roberto Arturo
A1  - Bergmann, Ronny
A1  - Schade, Matthias
A1  - Shai, Yechiel
A1  - Chiantia, Salvatore
A1  - Herrmann, Andreas
A1  - Schwarzer, Roland
T1  - Self-association and subcellular localization of Puumala hantavirus envelope proteins
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - Hantavirus assembly and budding are governed by the surface glycoproteins Gn and Gc. In this study, we investigated the glycoproteins of Puumala, the most abundant Hantavirus species in Europe, using fluorescently labeled wild-type constructs and cytoplasmic tail (CT) mutants. We analyzed their intracellular distribution, co-localization and oligomerization, applying comprehensive live, single-cell fluorescence techniques, including confocal microscopy, imaging flow cytometry, anisotropy imaging and Number&Brightness analysis. We demonstrate that Gc is significantly enriched in the Golgi apparatus in absence of other viral components, while Gn is mainly restricted to the endoplasmic reticulum (ER). Importantly, upon co-expression both glycoproteins were found in the Golgi apparatus. Furthermore, we show that an intact CT of Gc is necessary for efficient Golgi localization, while the CT of Gn influences protein stability. Finally, we found that Gn assembles into higher-order homo-oligomers, mainly dimers and tetramers, in the ER while Gc was present as mixture of monomers and dimers within the Golgi apparatus. Our findings suggest that PUUV Gc is the driving factor of the targeting of Gc and Gn to the Golgi region, while Gn possesses a significantly stronger self-association potential.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 648 
KW  - Sin-Nombre-Virus
KW  - nucleocapsid protein
KW  - cytoplasmic tails
KW  - electron cryotomography
KW  - autophagic clearance
KW  - glycoprotein
KW  - Gn
KW  - G1
KW  - brightness
KW  - fever
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-425040
SN  - 1866-8372
IS  - 648
ER  - 
TY  - JOUR
A1  - Enssle, Jörg
A1  - Weylandt, Karsten-Henrich
T1  - Secure and optimized detection of PNPLA3 rs738409 genotype by an improved PCR-restriction fragment length polymorphism method
JF  - BioTechniques : the international journal of life science methods
N2  - The PNPLA3 reference single-nucleotide polymorphism rs738409 has been identified as a predisposing factor for nonalcoholic fatty liver disease. A simple method based on PCR and restriction fragment length polymorphism (RFLP) analysis had been published to detect the nonpathogenic allele PNPLA3 rs738409 variant. The presence of the pathogenic variant was deduced by the indigestibility of the corresponding PCR product with BtsCI recognizing the nonpathogenic allele. However, one cannot exclude that an enzymatic reaction does not occur for other, more trivial, reasons. For safe and secure detection of the pathogenic PNPLA3 rs738409, we have further developed the PCR-restriction fragment length polymorphism method by adding a second restriction enzyme digest, clearly identifying the correct PNPLA3 alleles and in particular the pathogenic variant. <br /> METHOD SUMMARY <br /> The method presented here represents an improved genetic diagnosis of the PNPLA3 rs738409 alleles based on conventional and inexpensive molecular biological methods. We used methodology based on PCR and restriction fragment length polymorphisms and clearly identified both described alleles by the use of two restriction enzymes. Digestion of individuals' specific PNPLA3 PCR fragments with both enzymes in independent reactions clearly showed the PNPLA3 rs738409 genotype.
KW  - n-3 polyunsaturated fatty acid therapies
KW  - nonalcoholic fatty liver
KW  - disease
KW  - PCR– RFLP
KW  - PNPLA3
KW  - rs738409
Y1  - 2021
U6  - https://doi.org/10.2144/btn-2020-0163
SN  - 0736-6205
SN  - 1940-9818
VL  - 70
IS  - 6
SP  - 345
EP  - 349
PB  - Future Science Ltd.
CY  - London
ER  - 
TY  - GEN
A1  - Igual Gil, Carla
A1  - Ost, Mario
A1  - Kasch, Juliane
A1  - Schumann, Sara
A1  - Heider, Sarah
A1  - Klaus, Susanne
T1  - Role of GDF15 in active lifestyle induced metabolic adaptations and acute exercise response in mice
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - Physical activity is an important contributor to muscle adaptation and metabolic health. Growth differentiation factor 15 (GDF15) is established as cellular and nutritional stress-induced cytokine but its physiological role in response to active lifestyle or acute exercise is unknown. Here, we investigated the metabolic phenotype and circulating GDF15 levels in lean and obese male C57BI/6J mice with long-term voluntary wheel running (VWR) intervention. Additionally, treadmill running capacity and exercise-induced muscle gene expression was examined in GDF15-ablated mice. Active lifestyle mimic via VWR improved treadmill running performance and, in obese mice, also metabolic phenotype. The post-exercise induction of skeletal muscle transcriptional stress markers was reduced by VWR. Skeletal muscle GDF15 gene expression was very low and only transiently increased post-exercise in sedentary but not in active mice. Plasma GDF15 levels were only marginally affected by chronic or acute exercise. In obese mice, VWR reduced GDF15 gene expression in different tissues but did not reverse elevated plasma GDF15. Genetic ablation of GDF15 had no effect on exercise performance but augmented the post exercise expression of transcriptional exercise stress markers (Atf3, Atf6, and Xbp1s) in skeletal muscle. We conclude that skeletal muscle does not contribute to circulating GDF15 in mice, but muscle GDF15 might play a protective role in the exercise stress response.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1090 
KW  - skeletal-muscle
KW  - growth
KW  - induction
KW  - insulin
KW  - activation
KW  - increases
KW  - glucagon
KW  - health
KW  - gene
KW  - diet
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-460541
SN  - 1866-8372
IS  - 1090
ER  - 
TY  - JOUR
A1  - Fritsch, Daniel
T1  - Revisiting the Cu-Zn disorder in kesterite type Cu2ZnSnSe4 employing a novel approach to hybrid functional calculations
JF  - Applied Sciences : open access journal
N2  - In recent years, the search for more efficient and environmentally friendly materials to be employed in the next generation of thin film solar cell devices has seen a shift towards hybrid halide perovskites and chalcogenide materials crystallising in the kesterite crystal structure. Prime examples for the latter are Cu2ZnSnS4, Cu2ZnSnSe4, and their solid solution Cu2ZnSn(SxSe1-x)(4), where actual devices already demonstrated power conversion efficiencies of about 13 %. However, in their naturally occurring kesterite crystal structure, the so-called Cu-Zn disorder plays an important role and impacts the structural, electronic, and optical properties. To understand the influence of Cu-Zn disorder, we perform first-principles calculations based on density functional theory combined with special quasirandom structures to accurately model the cation disorder. Since the electronic band gaps and derived optical properties are severely underestimated by (semi)local exchange and correlation functionals, supplementary hybrid functional calculations have been performed. Concerning the latter, we additionally employ a recently devised technique to speed up structural relaxations for hybrid functional calculations. Our calculations show that the Cu-Zn disorder leads to a slight increase in the unit cell volume compared to the conventional kesterite structure showing full cation order, and that the band gap gets reduced by about 0.2 eV, which is in very good agreement with earlier experimental and theoretical findings. Our detailed results on structural, electronic, and optical properties will be discussed with respect to available experimental data, and will provide further insights into the atomistic origin of the disorder-induced band gap lowering in these promising kesterite type materials.
KW  - Cu2ZnSnSe4
KW  - CZTSe
KW  - chalcogenide
KW  - kesterite
KW  - Cu-Zn disorder
KW  - density
KW  - functional theory
KW  - hybrid functional
KW  - special quasirandom structure
Y1  - 2022
U6  - https://doi.org/10.3390/app12052576
SN  - 2076-3417
VL  - 12
IS  - 5
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Quante, Lennart
A1  - Willner, Sven N.
A1  - Middelanis, Robin
A1  - Levermann, Anders
T1  - Regions of intensification of extreme snowfall under future warming
JF  - Scientific reports
N2  - Due to climate change the frequency and character of precipitation are changing as the hydrological cycle intensifies. With regards to snowfall, global warming has two opposing influences; increasing humidity enables intense snowfall, whereas higher temperatures decrease the likelihood of snowfall. Here we show an intensification of extreme snowfall across large areas of the Northern Hemisphere under future warming. This is robust across an ensemble of global climate models when they are bias-corrected with observational data. While mean daily snowfall decreases, both the 99th and the 99.9th percentiles of daily snowfall increase in many regions in the next decades, especially for Northern America and Asia. Additionally, the average intensity of snowfall events exceeding these percentiles as experienced historically increases in many regions. This is likely to pose a challenge to municipalities in mid to high latitudes. Overall, extreme snowfall events are likely to become an increasingly important impact of climate change in the next decades, even if they will become rarer, but not necessarily less intense, in the second half of the century.
Y1  - 2021
U6  - https://doi.org/10.1038/s41598-021-95979-4
SN  - 2045-2322
VL  - 11
IS  - 1
PB  - Macmillan Publishers Limited, part of Springer Nature
CY  - Berlin
ER  - 
TY  - GEN
A1  - Lara, Mark J.
A1  - Nitze, Ingmar
A1  - Grosse, Guido
A1  - Martin, Philip
A1  - McGuire, A. David
T1  - Reduced arctic tundra productivity linked with landform and climate change interactions
T2  - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe
N2  - Arctic tundra ecosystems have experienced unprecedented change associated with climate warming over recent decades. Across the Pan-Arctic, vegetation productivity and surface greenness have trended positively over the period of satellite observation. However, since 2011 these trends have slowed considerably, showing signs of browning in many regions. It is unclear what factors are driving this change and which regions/landforms will be most sensitive to future browning. Here we provide evidence linking decadal patterns in arctic greening and browning with regional climate change and local permafrost-driven landscape heterogeneity. We analyzed the spatial variability of decadal-scale trends in surface greenness across the Arctic Coastal Plain of northern Alaska (similar to 60,000 km(2)) using the Landsat archive (1999-2014), in combination with novel 30 m classifications of polygonal tundra and regional watersheds, finding landscape heterogeneity and regional climate change to be the most important factors controlling historical greenness trends. Browning was linked to increased temperature and precipitation, with the exception of young landforms (developed following lake drainage), which will likely continue to green. Spatiotemporal model forecasting suggests carbon uptake potential to be reduced in response to warmer and/or wetter climatic conditions, potentially increasing the net loss of carbon to the atmosphere, at a greater degree than previously expected.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 550 
KW  - winter warming events
KW  - permafrost
KW  - Alaska
KW  - trends
KW  - ice
KW  - CO2
KW  - degradation
KW  - landscapes
KW  - ecosystem
KW  - exchange
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-423132
SN  - 1866-8372
IS  - 550
ER  - 
TY  - JOUR
A1  - Rosenblum, Michael
A1  - Pikovskij, Arkadij
A1  - Kühn, Andrea A.
A1  - Busch, Johannes Leon
T1  - Real-time estimation of phase and amplitude with application to neural data
JF  - Scientific reports
N2  - Computation of the instantaneous phase and amplitude via the Hilbert Transform is a powerful tool of data analysis. This approach finds many applications in various science and engineering branches but is not proper for causal estimation because it requires knowledge of the signal’s past and future. However, several problems require real-time estimation of phase and amplitude; an illustrative example is phase-locked or amplitude-dependent stimulation in neuroscience. In this paper, we discuss and compare three causal algorithms that do not rely on the Hilbert Transform but exploit well-known physical phenomena, the synchronization and the resonance. After testing the algorithms on a synthetic data set, we illustrate their performance computing phase and amplitude for the accelerometer tremor measurements and a Parkinsonian patient’s beta-band brain activity.
Y1  - 2021
U6  - https://doi.org/10.1038/s41598-021-97560-5
SN  - 2045-2322
VL  - 11
PB  - Springer Nature
CY  - London
ER  - 
TY  - JOUR
A1  - Seep, Lea
A1  - Razaghi-Moghadam, Zahra
A1  - Nikoloski, Zoran
T1  - Reaction lumping in metabolic networks for application with thermodynamic metabolic flux analysis
JF  - Scientific reports
N2  - Thermodynamic metabolic flux analysis (TMFA) can narrow down the space of steady-state flux distributions, but requires knowledge of the standard Gibbs free energy for the modelled reactions. The latter are often not available due to unknown Gibbs free energy change of formation ,Delta fG0, of metabolites. To optimize the usage of data on thermodynamics in constraining a model, reaction lumping has been proposed to eliminate metabolites with unknown Delta fG0. However, the lumping procedure has not been formalized nor implemented for systematic identification of lumped reactions. Here, we propose, implement, and test a combined procedure for reaction lumping, applicable to genome-scale metabolic models. It is based on identification of groups of metabolites with unknown Delta fG0 whose elimination can be conducted independently of the others via: (1) group implementation, aiming to eliminate an entire such group, and, if this is infeasible, (2) a sequential implementation to ensure that a maximal number of metabolites with unknown Delta fG0 are eliminated. Our comparative analysis with genome-scale metabolic models of Escherichia coli, Bacillus subtilis, and Homo sapiens shows that the combined procedure provides an efficient means for systematic identification of lumped reactions. We also demonstrate that TMFA applied to models with reactions lumped according to the proposed procedure lead to more precise predictions in comparison to the original models. The provided implementation thus ensures the reproducibility of the findings and their application with standard TMFA.
Y1  - 2021
U6  - https://doi.org/10.1038/s41598-021-87643-8
SN  - 2045-2322
VL  - 11
IS  - 1
PB  - Macmillan Publishers Limited, part of Springer Nature
CY  - London
ER  - 
TY  - JOUR
A1  - Wetzel, Maria
A1  - Kempka, Thomas
A1  - Kühn, Michael
T1  - Quantifying rock weakening due to decreasing calcite mineral content by numerical simulations
JF  - Materials
N2  - The quantification of changes in geomechanical properties due to chemical reactions is of paramount importance for geological subsurface utilisation, since mineral dissolution generally reduces rock stiffness. In the present study, the effective elastic moduli of two digital rock samples, the Fontainebleau and Bentheim sandstones, are numerically determined based on micro-CT images. Reduction in rock stiffness due to the dissolution of 10% calcite cement by volume out of the pore network is quantified for three synthetic spatial calcite distributions (coating, partial filling and random) using representative sub-cubes derived from the digital rock samples. Due to the reduced calcite content, bulk and shear moduli decrease by 34% and 38% in maximum, respectively. Total porosity is clearly the dominant parameter, while spatial calcite distribution has a minor impact, except for a randomly chosen cement distribution within the pore network. Moreover, applying an initial stiffness reduced by 47% for the calcite cement results only in a slightly weaker mechanical behaviour. Using the quantitative approach introduced here substantially improves the accuracy of predictions in elastic rock properties compared to general analytical methods, and further enables quantification of uncertainties related to spatial variations in porosity and mineral distribution.
KW  - digital rock physics
KW  - micro-CT
KW  - elastic properties
KW  - numerical simulation
KW  - chemical-mechanical interaction
KW  - Code_Aster
KW  - composite properties
Y1  - 2018
U6  - https://doi.org/10.3390/ma11040542
SN  - 1996-1944
VL  - 11
IS  - 4
PB  - MDPI
CY  - Basel
ER  - 
TY  - GEN
A1  - Wetzel, Maria
A1  - Kempka, Thomas
A1  - Kühn, Michael
T1  - Quantifying rock weakening due to decreasing calcite mineral content by numerical simulations
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - The quantification of changes in geomechanical properties due to chemical reactions is of paramount importance for geological subsurface utilisation, since mineral dissolution generally reduces rock stiffness. In the present study, the effective elastic moduli of two digital rock samples, the Fontainebleau and Bentheim sandstones, are numerically determined based on micro-CT images. Reduction in rock stiffness due to the dissolution of 10% calcite cement by volume out of the pore network is quantified for three synthetic spatial calcite distributions (coating, partial filling and random) using representative sub-cubes derived from the digital rock samples. Due to the reduced calcite content, bulk and shear moduli decrease by 34% and 38% in maximum, respectively. Total porosity is clearly the dominant parameter, while spatial calcite distribution has a minor impact, except for a randomly chosen cement distribution within the pore network. Moreover, applying an initial stiffness reduced by 47% for the calcite cement results only in a slightly weaker mechanical behaviour. Using the quantitative approach introduced here substantially improves the accuracy of predictions in elastic rock properties compared to general analytical methods, and further enables quantification of uncertainties related to spatial variations in porosity and mineral distribution.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1092 
KW  - digital rock physics
KW  - micro-CT
KW  - elastic properties
KW  - numerical simulation
KW  - chemical-mechanical interaction
KW  - Code_Aster
KW  - composite properties
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-473089
SN  - 1866-8372
IS  - 1092
ER  - 
TY  - GEN
A1  - Ziege, Madlen
A1  - Theodorou, Panagiotis
A1  - Jüngling, Hannah
A1  - Merker, Stefan
A1  - Plath, Martin
A1  - Streit, Bruno
A1  - Lerp, Hannes
T1  - Population genetics of the European rabbit along a rural-to-urban gradient
T2  - Postprints der Universität Potsdam : Mathematisch Naturwissenschaftliche Reihe
N2  - The European rabbit (Oryctolagus cuniculus) is declining in large parts of Europe but populations in some German cities remained so far unaffected by this decline. The question arises of how urbanization affects patterns of population genetic variation and differentiation in German rabbit populations, as urban habitat fragmentation may result in altered meta-population dynamics. To address this question, we used microsatellite markers to genotype rabbit populations occurring along a rural-to-urban gradient in and around the city of Frankfurt, Germany. We found no effect of urbanization on allelic richness. However, the observed heterozygosity was significantly higher in urban than rural populations and also the inbreeding coefficients were lower, most likely reflecting the small population sizes and possibly on-going loss of genetic diversity in structurally impoverished rural areas. Global FST and G'ST-values suggest moderate but significant differentiation between populations. Multiple matrix regression with randomization ascribed this differentiation to isolation-by-environment rather than isolation-by-distance. Analyses of migration rates revealed asymmetrical gene flow, which was higher from rural into urban populations than vice versa and may again reflect intensified agricultural land-use practices in rural areas. We discuss that populations inhabiting urban areas will likely play an important role in the future distribution of European rabbits.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 880 
KW  - Conservation biology
KW  - Genetics
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-460354
SN  - 1866-8372
IS  - 880
ER  - 
TY  - JOUR
A1  - Ziege, Madlen
A1  - Theodorou, Panagiotis
A1  - Jüngling, Hannah
A1  - Merker, Stefan
A1  - Plath, Martin
A1  - Streit, Bruno
A1  - Lerp, Hannes
T1  - Population genetics of the European rabbit along a rural-to-urban gradient
JF  - Scientific Reports
N2  - The European rabbit (Oryctolagus cuniculus) is declining in large parts of Europe but populations in some German cities remained so far unaffected by this decline. The question arises of how urbanization affects patterns of population genetic variation and differentiation in German rabbit populations, as urban habitat fragmentation may result in altered meta-population dynamics. To address this question, we used microsatellite markers to genotype rabbit populations occurring along a rural-to-urban gradient in and around the city of Frankfurt, Germany. We found no effect of urbanization on allelic richness. However, the observed heterozygosity was significantly higher in urban than rural populations and also the inbreeding coefficients were lower, most likely reflecting the small population sizes and possibly on-going loss of genetic diversity in structurally impoverished rural areas. Global FST and G'ST-values suggest moderate but significant differentiation between populations. Multiple matrix regression with randomization ascribed this differentiation to isolation-by-environment rather than isolation-by-distance. Analyses of migration rates revealed asymmetrical gene flow, which was higher from rural into urban populations than vice versa and may again reflect intensified agricultural land-use practices in rural areas. We discuss that populations inhabiting urban areas will likely play an important role in the future distribution of European rabbits.
KW  - Conservation biology
KW  - Genetics
Y1  - 2018
U6  - https://doi.org/10.1038/s41598-020-57962-3
SN  - 2045-2322
VL  - 10
PB  - Nature Publ. Group
CY  - London
ER  - 
TY  - GEN
A1  - Niebuur, Bart-Jan
A1  - Puchmayr, Jonas
A1  - Herold, Christian
A1  - Kreuzer, Lucas
A1  - Hildebrand, Viet
A1  - Müller-Buschbaum, Peter
A1  - Laschewsky, André
A1  - Papadakis, Christine M.
T1  - Polysulfobetaines in aqueous solution and in thin film geometry
T2  - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe
N2  - Polysulfobetaines in aqueous solution show upper critical solution temperature (UCST) behavior. We investigate here the representative of this class of materials, poly (N,N-dimethyl-N-(3-methacrylamidopropyl) ammonio propane sulfonate) (PSPP), with respect to: (i) the dynamics in aqueous solution above the cloud point as function of NaBr concentration; and (ii) the swelling behavior of thin films in water vapor as function of the initial film thickness. For PSPP solutions with a concentration of 5 wt.%, the temperature dependence of the intensity autocorrelation functions is measured with dynamic light scattering as function of molar mass and NaBr concentration (0–8 mM). We found a scaling of behavior for the scattered intensity and dynamic correlation length. The resulting spinodal temperatures showed a maximum at a certain (small) NaBr concentration, which is similar to the behavior of the cloud points measured previously by turbidimetry. The critical exponent of susceptibility depends on NaBr concentration, with a minimum value where the spinodal temperature is maximum and a trend towards the mean-field value of unity with increasing NaBr concentration. In contrast, the critical exponent of the correlation length does not depend on NaBr concentration and is lower than the value of 0.5 predicted by mean-field theory. For PSPP thin films, the swelling behavior was found to depend on film thickness. A film thickness of about 100 nm turns out to be the optimum thickness needed to obtain fast hydration with H 2 O.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 713 
KW  - polyzwitterions
KW  - polysulfobetaines
KW  - dynamic light scattering
KW  - phase behavior
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-427363
SN  - 1866-8372
IS  - 713
ER  - 
TY  - JOUR
A1  - Bouncken, Ricarda B.
A1  - Ratzmann, Martin
A1  - Tiberius, Victor
A1  - Brem, Alexander
T1  - Pioneering strategy in supply chain relationships
BT  - how coercive power and contract completeness influence innovation
JF  - IEEE transactions on engineering management
N2  - Today, firms pursuing a pioneering strategy are often engaged in supply chain relationships to benefit from external resources and to improve their innovation. However, this effort can be impeded by power asymmetries in such relationships and especially by the execution of coercive power by their partner firm. Contracts could potentially reduce this risk of opportunistic behavior. Our survey study on 778 small to medium-sized enterprises in the European packaging and medical equipment industries examines how coercive power of the partner and the contractual arrangement between firms moderate the pioneering strategy's innovation outcomes in the short and long run. Our results confirm the negative effect of coercive power on innovation performance in both the short and long term. However, the compensating effect of rather complete contracts differs temporally. Whereas, contract completeness protects against higher dependence at the beginning of the collaboration, their effect diminishes over time. In contrast, rather incomplete contracts enhance the innovation performance in the long term, possibly complemented with trust.
KW  - alliances
KW  - coercive power
KW  - contracts
KW  - pioneering strategy
KW  - R&D
KW  - supply chain
Y1  - 2020
U6  - https://doi.org/10.1109/TEM.2020.3019965
SN  - 0018-9391
VL  - 69
IS  - 6
SP  - 2826
EP  - 2841
PB  - IEEE
CY  - New York
ER  - 
TY  - GEN
A1  - Schaefer, Laura
A1  - Bittmann, Frank
T1  - Parkinson patients without tremor show changed patterns of mechanical muscle oscillations during a specific bilateral motor task compared to controls
T2  - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe
N2  - The pathophysiology of Parkinson’s disease (PD) is still not understood. There are investigations which show a changed oscillatory behaviour of brain circuits or changes in variability of, e.g., gait parameters in PD. The aim of this study was to investigate whether or not the motor output differs between PD patients and healthy controls. Thereby, patients without tremor are investigated in the medication off state performing a special bilateral isometric motor task. The force and accelerations (ACC) were recorded as well as the Mechanomyography (MMG) of the biceps brachii, the brachioradialis and of the pectoralis major muscles using piezoelectric-sensors during the bilateral motor task at 60% of the maximal isometric contraction. The frequency, a specific power ratio, the amplitude variation and the slope of amplitudes were analysed. The results indicate that the oscillatory behaviour of motor output in PD patients without tremor deviates from controls: thereby, the 95%-confidence-intervals of power ratio and of amplitude variation of all signals are disjoint between PD and controls and show significant differences in group comparisons (power ratio: p = 0.000–0.004, r = 0.441–0.579; amplitude variation: p = 0.000–0.001, r = 0.37–0.67). The mean frequency shows a significant difference for ACC (p = 0.009, r = 0.43), but not for MMG. It remains open, whether this muscular output reflects changes of brain circuits and whether the results are reproducible and specific for PD.
T3  - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 602 
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-445431
SN  - 1866-8364
IS  - 602
ER  - 
TY  - JOUR
A1  - Schaefer, Laura
A1  - Bittmann, Frank
T1  - Parkinson patients without tremor show changed patterns of mechanical muscle oscillations during a specific bilateral motor task compared to controls
JF  - Scientific Reports
N2  - The pathophysiology of Parkinson’s disease (PD) is still not understood. There are investigations which show a changed oscillatory behaviour of brain circuits or changes in variability of, e.g., gait parameters in PD. The aim of this study was to investigate whether or not the motor output differs between PD patients and healthy controls. Thereby, patients without tremor are investigated in the medication off state performing a special bilateral isometric motor task. The force and accelerations (ACC) were recorded as well as the Mechanomyography (MMG) of the biceps brachii, the brachioradialis and of the pectoralis major muscles using piezoelectric-sensors during the bilateral motor task at 60% of the maximal isometric contraction. The frequency, a specific power ratio, the amplitude variation and the slope of amplitudes were analysed. The results indicate that the oscillatory behaviour of motor output in PD patients without tremor deviates from controls: thereby, the 95%-confidence-intervals of power ratio and of amplitude variation of all signals are disjoint between PD and controls and show significant differences in group comparisons (power ratio: p = 0.000–0.004, r = 0.441–0.579; amplitude variation: p = 0.000–0.001, r = 0.37–0.67). The mean frequency shows a significant difference for ACC (p = 0.009, r = 0.43), but not for MMG. It remains open, whether this muscular output reflects changes of brain circuits and whether the results are reproducible and specific for PD.
Y1  - 2020
U6  - https://doi.org/10.1038/s41598-020-57766-5
SN  - 2045-2322
VL  - 10
PB  - Macmillan Publishers Limited, part of Springer Nature
CY  - London
ER  - 
TY  - GEN
A1  - Meyer, Matthias
A1  - Palkopoulou, Eleftheria
A1  - Baleka, Sina Isabelle
A1  - Stiller, Mathias
A1  - Penkman, Kirsty E. H.
A1  - Alt, Kurt W.
A1  - Ishida, Yasuko
A1  - Mania, Dietrich
A1  - Mallick, Swapan
A1  - Meijer, Tom
A1  - Meller, Harald
A1  - Nagel, Sarah
A1  - Nickel, Birgit
A1  - Ostritz, Sven
A1  - Rohland, Nadin
A1  - Schauer, Karol
A1  - Schüler, Tim
A1  - Roca, Alfred L.
A1  - Reich, David
A1  - Shapiro, Beth
A1  - Hofreiter, Michael
T1  - Palaeogenomes of Eurasian straight-tusked elephants challenge the current view of elephant evolution
T2  - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe
N2  - The straight-tusked elephants Palaeoloxodon spp. were widespread across Eurasia during the Pleistocene. Phylogenetic reconstructions using morphological traits have grouped them with Asian elephants (Elephas maximus), and many paleontologists place Palaeoloxodon within Elephas. Here, we report the recovery of full mitochondrial genomes from four and partial nuclear genomes from two P. antiquus fossils. These fossils were collected at two sites in Germany, Neumark-Nord and Weimar-Ehringsdorf, and likely date to interglacial periods similar to 120 and similar to 244 thousand years ago, respectively. Unexpectedly, nuclear and mitochondrial DNA analyses suggest that P. antiquus was a close relative of extant African forest elephants (Loxodonta cyclotis). Species previously referred to Palaeoloxodon are thus most parsimoniously explained as having diverged from the lineage of Loxodonta, indicating that Loxodonta has not been constrained to Africa. Our results demonstrate that the current picture of elephant evolution is in need of substantial revision.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 790 
KW  - genome sequence
KW  - woolly mammoth
KW  - Palaeoloxodon-antiquus
KW  - phylogenetic analysis
KW  - African elephants
KW  - DNA
KW  - Pleistocene
KW  - alignment
KW  - ancient
KW  - reveal
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-440139
SN  - 1866-8372
IS  - 790
ER  - 
TY  - GEN
A1  - Caprioglio, Pietro
A1  - Stolterfoht, Martin
A1  - Wolff, Christian Michael
A1  - Unold, Thomas
A1  - Rech, Bernd
A1  - Albrecht, Steve
A1  - Neher, Dieter
T1  - On the relation between the open‐circuit voltage and quasi‐Fermi level splitting in efficient perovskite solar cells
T2  - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe
N2  - Today's perovskite solar cells (PSCs) are limited mainly by their open‐circuit voltage (VOC) due to nonradiative recombination. Therefore, a comprehensive understanding of the relevant recombination pathways is needed. Here, intensity‐dependent measurements of the quasi‐Fermi level splitting (QFLS) and of the VOC on the very same devices, including pin‐type PSCs with efficiencies above 20%, are performed. It is found that the QFLS in the perovskite lies significantly below its radiative limit for all intensities but also that the VOC is generally lower than the QFLS, violating one main assumption of the Shockley‐Queisser theory. This has far‐reaching implications for the applicability of some well‐established techniques, which use the VOC as a measure of the carrier densities in the absorber. By performing drift‐diffusion simulations, the intensity dependence of the QFLS, the QFLS‐VOC offset and the ideality factor are consistently explained by trap‐assisted recombination and energetic misalignment at the interfaces. Additionally, it is found that the saturation of the VOC at high intensities is caused by insufficient contact selectivity while heating effects are of minor importance. It is concluded that the analysis of the VOC does not provide reliable conclusions of the recombination pathways and that the knowledge of the QFLS‐VOC relation is of great importance.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 774 
KW  - electro‐optical materials
KW  - perovskite solar cells
KW  - photovoltaic devices
KW  - thin films
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-437595
SN  - 1866-8372
IS  - 774
ER  - 
TY  - JOUR
A1  - Caprioglio, Pietro
A1  - Stolterfoht, Martin
A1  - Wolff, Christian Michael
A1  - Unold, Thomas
A1  - Rech, Bernd
A1  - Albrecht, Steve
A1  - Neher, Dieter
T1  - On the relation between the open-circuit voltage and quasi-fermi level splitting in efficient perovskite solar cells
JF  - advanced energy materials
N2  - Today's perovskite solar cells (PSCs) are limited mainly by their open‐circuit voltage (VOC) due to nonradiative recombination. Therefore, a comprehensive understanding of the relevant recombination pathways is needed. Here, intensity‐dependent measurements of the quasi‐Fermi level splitting (QFLS) and of the VOC on the very same devices, including pin‐type PSCs with efficiencies above 20%, are performed. It is found that the QFLS in the perovskite lies significantly below its radiative limit for all intensities but also that the VOC is generally lower than the QFLS, violating one main assumption of the Shockley‐Queisser theory. This has far‐reaching implications for the applicability of some well‐established techniques, which use the VOC as a measure of the carrier densities in the absorber. By performing drift‐diffusion simulations, the intensity dependence of the QFLS, the QFLS‐VOC offset and the ideality factor are consistently explained by trap‐assisted recombination and energetic misalignment at the interfaces. Additionally, it is found that the saturation of the VOC at high intensities is caused by insufficient contact selectivity while heating effects are of minor importance. It is concluded that the analysis of the VOC does not provide reliable conclusions of the recombination pathways and that the knowledge of the QFLS‐VOC relation is of great importance.
KW  - electro-optical materials
KW  - perovskite solar cells
KW  - photovoltaic devices
KW  - thin films
Y1  - 2019
U6  - https://doi.org/10.1002/aenm.201901631
SN  - 1614-6832
SN  - 1614-6840
VL  - 9
IS  - 33
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - GEN
A1  - Dammhahn, Melanie
A1  - Mazza, Valeria
A1  - Schirmer, Annika
A1  - Göttsche, Claudia
A1  - Eccard, Jana
T1  - Of city and village mice
BT  - behavioural adjustments of striped field mice to urban environments
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - A fundamental question of current ecological research concerns the drives and limits of species responses to human-induced rapid environmental change (HIREC). Behavioural responses to HIREC are a key component because behaviour links individual responses to population and community changes. Ongoing fast urbanization provides an ideal setting to test the functional role of behaviour for responses to HIREC. Consistent behavioural differences between conspecifics (animal personality) may be important determinants or constraints of animals’ adaptation to urban habitats. We tested whether urban and rural populations of small mammals differ in mean trait expression, flexibility and repeatability of behaviours associated to risk-taking and exploratory tendencies. Using a standardized behavioural test in the field, we quantified spatial exploration and boldness of striped field mice (Apodemus agrarius, n = 96) from nine sub-populations, presenting different levels of urbanisation and anthropogenic disturbance. The level of urbanisation positively correlated with boldness, spatial exploration and behavioural flexibility, with urban dwellers being bolder, more explorative and more flexible in some traits than rural conspecifics. Thus, individuals seem to distribute in a non-random way in response to human disturbance based on their behavioural characteristics. Animal personality might therefore play a key role in successful coping with the challenges of HIREC.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1007 
KW  - personality-traits
KW  - apodemus-agrarius
KW  - exploratory-behavior
KW  - fitness consequences
KW  - individual variation
KW  - avian personalities
KW  - animal personality
KW  - rural populations
KW  - natural-selection
KW  - natal dispersal
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-480063
SN  - 1866-8372
IS  - 1007
ER  - 
TY  - JOUR
A1  - Dammhahn, Melanie
A1  - Mazza, Valeria
A1  - Schirmer, Annika
A1  - Göttsche, Claudia
A1  - Eccard, Jana
T1  - Of city and village mice
BT  - behavioural adjustments of striped field mice to urban environments
JF  - Scientific Reports
N2  - A fundamental question of current ecological research concerns the drives and limits of species responses to human-induced rapid environmental change (HIREC). Behavioural responses to HIREC are a key component because behaviour links individual responses to population and community changes. Ongoing fast urbanization provides an ideal setting to test the functional role of behaviour for responses to HIREC. Consistent behavioural differences between conspecifics (animal personality) may be important determinants or constraints of animals’ adaptation to urban habitats. We tested whether urban and rural populations of small mammals differ in mean trait expression, flexibility and repeatability of behaviours associated to risk-taking and exploratory tendencies. Using a standardized behavioural test in the field, we quantified spatial exploration and boldness of striped field mice (Apodemus agrarius, n = 96) from nine sub-populations, presenting different levels of urbanisation and anthropogenic disturbance. The level of urbanisation positively correlated with boldness, spatial exploration and behavioural flexibility, with urban dwellers being bolder, more explorative and more flexible in some traits than rural conspecifics. Thus, individuals seem to distribute in a non-random way in response to human disturbance based on their behavioural characteristics. Animal personality might therefore play a key role in successful coping with the challenges of HIREC.
KW  - personality-traits
KW  - apodemus-agrarius
KW  - exploratory-behavior
KW  - fitness consequences
KW  - individual variation
KW  - avian personalities
KW  - animal personality
KW  - rural populations
KW  - natural-selection
KW  - natal dispersal
Y1  - 2020
U6  - https://doi.org/10.1038/s41598-020-69998-6
SN  - 2045-2322
VL  - 10
PB  - Macmillan Publishers Limited
CY  - London
ER  - 
TY  - JOUR
A1  - Agarwal, Ankit
A1  - Caesar, Levke
A1  - Marwan, Norbert
A1  - Maheswaran, Rathinasamy
A1  - Merz, Bruno
T1  - Network-based identification and characterization of teleconnections on different scales
JF  - Scientific Reports
N2  - Sea surface temperature (SST) patterns can – as surface climate forcing – affect weather and climate at large distances. One example is El Niño-Southern Oscillation (ENSO) that causes climate anomalies around the globe via teleconnections. Although several studies identified and characterized these teleconnections, our understanding of climate processes remains incomplete, since interactions and feedbacks are typically exhibited at unique or multiple temporal and spatial scales. This study characterizes the interactions between the cells of a global SST data set at different temporal and spatial scales using climate networks. These networks are constructed using wavelet multi-scale correlation that investigate the correlation between the SST time series at a range of scales allowing instantaneously deeper insights into the correlation patterns compared to traditional methods like empirical orthogonal functions or classical correlation analysis. This allows us to identify and visualise regions of – at a certain timescale – similarly evolving SSTs and distinguish them from those with long-range teleconnections to other ocean regions. Our findings re-confirm accepted knowledge about known highly linked SST patterns like ENSO and the Pacific Decadal Oscillation, but also suggest new insights into the characteristics and origins of long-range teleconnections like the connection between ENSO and Indian Ocean Dipole.
Y1  - 2019
U6  - https://doi.org/10.1038/s41598-019-45423-5
SN  - 2045-2322
VL  - 9
PB  - Macmillan Publishers Limited
CY  - London
ER  - 
TY  - GEN
A1  - Agarwal, Ankit
A1  - Caesar, Levke
A1  - Marwan, Norbert
A1  - Maheswaran, Rathinasamy
A1  - Merz, Bruno
T1  - Network-based identification and characterization of teleconnections on different scales
T2  - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe
N2  - Sea surface temperature (SST) patterns can – as surface climate forcing – affect weather and climate at large distances. One example is El Niño-Southern Oscillation (ENSO) that causes climate anomalies around the globe via teleconnections. Although several studies identified and characterized these teleconnections, our understanding of climate processes remains incomplete, since interactions and feedbacks are typically exhibited at unique or multiple temporal and spatial scales. This study characterizes the interactions between the cells of a global SST data set at different temporal and spatial scales using climate networks. These networks are constructed using wavelet multi-scale correlation that investigate the correlation between the SST time series at a range of scales allowing instantaneously deeper insights into the correlation patterns compared to traditional methods like empirical orthogonal functions or classical correlation analysis. This allows us to identify and visualise regions of – at a certain timescale – similarly evolving SSTs and distinguish them from those with long-range teleconnections to other ocean regions. Our findings re-confirm accepted knowledge about known highly linked SST patterns like ENSO and the Pacific Decadal Oscillation, but also suggest new insights into the characteristics and origins of long-range teleconnections like the connection between ENSO and Indian Ocean Dipole.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 731 
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-430520
SN  - 1866-8372
IS  - 731
ER  - 
TY  - GEN
A1  - Weber, Edzard
A1  - Tiefenbacher, Anselm
A1  - Gronau, Norbert
T1  - Need for standardization and systematization of test data for job-shop scheduling
T2  - Postprints der Universität Potsdam Wirtschafts- und Sozialwissenschaftliche Reihe
N2  - The development of new and better optimization and approximation methods for Job Shop Scheduling Problems (JSP) uses simulations to compare their performance. The test data required for this has an uncertain influence on the simulation results, because the feasable search space can be changed drastically by small variations of the initial problem model. Methods could benefit from this to varying degrees. This speaks in favor of defining standardized and reusable test data for JSP problem classes, which in turn requires a systematic describability of the test data in order to be able to compile problem adequate data sets. This article looks at the test data used for comparing methods by literature review. It also shows how and why the differences in test data have to be taken into account. From this, corresponding challenges are derived which the management of test data must face in the context of JSP research.
Keywords
T3  - Zweitveröffentlichungen der Universität Potsdam : Wirtschafts- und Sozialwissenschaftliche Reihe - 134 
KW  - job shop scheduling
KW  - JSP
KW  - social network analysis
KW  - method comparision
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-472229
SN  - 1867-5808
IS  - 134
ER  -