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 - JOUR A1 - Distelmeyer, Jan T1 - From object to process BT - Interface politics of networked computerization JF - Artnodes N2 - One of the most difficult tasks today is trying to grasp the presence of computing. The almost ubiquitous and diverse forms of networked computers (in all their stationary, mobile, embedded, and autonomous modes) create a nearly overwhelming complexity. To speak of what is here evading and present at the same time, the paper proposes to reconsider the concept of interface, its historical roots, and its heuristic advantages for an analysis and critique of the current and especially everyday spread of computerization. The question of interfaces leads to isolable conditions and processes of conduction, as well as to the complexity of the cooperation formed by them. It opens both an investigative horizon and a mode of analysis, which always asks for further interface levels involved in the phenomenon I am currently investigating. As an example, the paper turns to the displacement of the file with the launch of the iPhone in 2007 and its comeback in 2017 with the "Files" apps. Both developments are profoundly related to the establishment of computers as permanently networked machines, whereby their functionality, depresentations, and ideology come into focus. KW - interface KW - conduction KW - network KW - ideology KW - depresentation KW - digital objects Y1 - 2019 U6 - https://doi.org/10.7238/a.v0i24.3300 SN - 1695-5951 IS - 24 SP - 83 EP - 90 PB - Universitat Oberta de Catalunya CY - Barcelona ER - TY - JOUR A1 - Fritz, Amelie A1 - Makeyeva, Angelina A1 - Staub, Kaspar A1 - Groth, Detlef T1 - Influence of network properties on a migration induced secular height trend by Monte Carlo simulation JF - Journal of biological and clinical anthropology : Anthropologischer Anzeiger ; Mitteilungsorgan der Gesellschaft für Anthropologie N2 - Background: Recent research reported height biased migration of taller individuals and a Monte Carlo simulation showed that such preferential migration of taller individuals into network hubs can induce a secular trend of height. In the simulation model taller agents in the hubs raise the overall height of all individuals in the network by a community effect. However, it could be seen that the actual network structure influences the strength of this effect. In this paper the background and the influence of the network structure on the strength of the secular trend by migration is investigated. Material and methods: Three principal network types are analyzed: networks derived from street connections in Switzerland, more regular fishing net like networks and randomly generated ones. Our networks have between 10 and 152 nodes and between 20 and 307 edges connecting the nodes. Depending on the network size between 5.000 and 90.000 agents with an average height of 170 cm (SD 6.5 cm) are initially released into the network. In each iteration new agents are regenerated based on the actual average body height of the previous iteration and, to a certain proportion, corrected by body heights in the neighboring nodes. After generating new agents, a certain number of them migrated into neighbor nodes, the model let preferentially taller agents migrate into network hubs. Migration is balanced by back migration of the same number of agents from nodes with high centrality measures to less connected nodes. The latter is random as well, but not biased by the agents height. Furthermore the distribution of agents per node and their correlation to the centrality of the nodes is varied in a systematic manner. After 100 iterations, the secular trend, i.e. the gain in body height for the different networks, is investigated in relation to the network properties. Results: We observe an increase of average agent body height after 100 iterations if height biased migration is enabled. The increase rate depends on the height of the neighboring factor, the population distribution, the relationship between population in the nodes and their centrality as well as on the network topology. Networks with uniform like distributions of the agents in the nodes, uncorrelated associations between node centrality and agent number per node, as well as very heterogeneous networks with very different node centralities lead to biggest gains in average body height. Conclusion: Our simulations show, that height biased migration into network hubs can possibly contribute to the secular trend of height increase in the human population. The strength of this "tall by migration" event depends on the actual properties of the underlying network. There is a possible significance of this mechanism for social networks, when hubs are represented by individuals and edges as their personal relationships. However, the required high number of iterations to achieve significant effects in more natural network structures in our models requires further studies to test the relevance and real effect sizes in real world scenarios. KW - secular trend KW - body height KW - simulation KW - community effect KW - Monte Carlo method KW - network KW - centrality measures Y1 - 2019 U6 - https://doi.org/10.1127/anthranz/2019/1032 SN - 0003-5548 VL - 76 IS - 5 SP - 433 EP - 443 PB - Schweizerbart CY - Stuttgart ER - TY - THES A1 - Gause, Clemens T1 - Das System der Strategie : ein Vergleich zwischen Strategien biologischer Systeme und militärischen Strategien ; eine Modellentwicklung T1 - The system of strategy : a comparison between strategies of biological systems and military strategies ; a model development N2 - Das vorliegende Buch vergleicht Strategien biologischer Systeme mit militärischen Strategien. Die zentrale Fragestellung ist dabei darauf gerichtet, ob es neben systemischen Gemeinsamkeiten auch gemeinsame oder ähnliche Strukturmuster und ähnliche Prozessabläufe beispielsweise sowohl im biologischen Abwehrmechanismus des Immunsystems und bei Insektenstaaten als auch bei Prozessen im Militär gibt. Vor diesem Hintergrund klaffen in der Theorie der Strategie, speziell in den Militärwissenschaften Lücken, denn der Systemansatz wird nicht konsequent beachtet, wie in diesem Buch mehrfach nachgewiesen ist. Von einem allgemeinen Verständnis der Strategie als bewusstem planerischem Vorgehen ist Abstand zu nehmen. Ausgehend von der Methode der Analogie und des Vergleichs wird im theoretischen Teil dieses Buches die Allgemeine Systemtheorie erläutert. Dabei werden der Begriff der Strategie ebenso wie die Begriffe Struktur und Prozess und Ansätze aus der Kriegsphilosophie von Clausewitz untersucht. Den Ausgangspunkt und schließlich auch wieder den Endpunkt der Überlegungen bilden neben dem notwendigen weiten Verständnis von Strategie, vor allem der Begriff der Organisation, ihrer Umwelt und der in diesem Zusammenhang bestehenden Wechselwirkung. Sowohl die Wechselwirkung von Umwelt und System als auch ihre Abhängigkeit durch strukturelle Kopplung werden beschrieben. Das Zusammenspiel und die daraus entstehende Komplexität der fünf Komponenten der Wahrnehmung, der Information und der Führung im Zusammenhang der Komponenten von Raum und Zeit in einem sozialen System lassen die klassische Ziel-Mittel-Zweck-Beziehung Clausewitz´scher Strategiedefinition verkürzt erscheinen. Anhand eines kurzen Rekurses der Methoden der Sozialen Netzwerkanalyse (SNA) wird der breite und tiefgehende Analyserahmen der Messung und Transparenzerreichung in Organisationen vorgestellt. Die SNA wird als Ausprägung der Netzwerk- und Graphentheorie, in die Allgemeine Systemtheorie integriert. Sie bildet eine zukunftsweisende Methode der Untersuchung von Netzwerken wie etwa dem Internet (Facebook, Xing etc.). Der aufgezeigte Theorierahmen bildet dabei zugleich eine Methode für den Systemvergleich und kann als Vorgehensmodell künftiger Strategieentwicklung genutzt werden. Der anschließende Systemvergleich wird mit mehreren Beispielen durchgeführt. Ausgehend von der Zelle als Grundeinheit werden Strukturen und Prozesse des Immunsystems mit solchen in militärischen Strukturen, weil sie im Lauf der Evolution enorme Leistungen in Reaktion, Anpassung und Optimierung vollbracht haben. Der Vergleich geht der Frage nach, ob in diesen Bereichen der Strategie und Organisation systemische Grundregeln existieren. Das Beispiel der Wechselwirkung zwischen Parasit und Wirt zeigt, dass jeder Fortschritt und Sieg angesichts der Systemeinbettung von Strategie nur relativ wirken kann. Die Analogie zwischen Viren und Bakterien sowie die Entwicklung des Begriffs der sozialen Mimikry führen zu einem erweiterten Verständnis der Strategie von Terroristen in sozialen Systemen. Verdeutlicht wird das Grundschema des Täuschens und Eindringens in Systeme sowie die Beeinflussung und Umsteuerung von Prozessen und Strukturen in einem System durch Kommunikation und Implementation von Codes. Am Beispiel des Immunsystems und der Bildung verschiedener Kommunikations- und Steuerungsmechanismen von Zellsystemen sowie Beispielen von Schwarmbildung und der Organisation sozialer Insekten werden eine Vielzahl heuristischer Hinweise für neue Ansätze für die Organisation von Streitkräften und ihrer Steuerung gefunden. Neben der Erarbeitung eines grundlegenden Strategiebegriffs anhand von Wahrnehmung und Selektion als Grundprozess der Erzeugung von Strategie wird eine differenzierte Betrachtung von Begriffen wie Redundanz und Robustheit sowie eine relativierende Sichtweise von Risiko, Gefahr und Schaden gewonnen. Der Vergleich mit dem Immunsystems zeigt einfache Beispiele der Informationsspeicherung und -übertragung, die zudem Bypassfähigkeiten sowie dezentrale Eskalations- und Deeskalationsprinzipien veranschaulichen. Dies eröffnet in Analogie dieser Prinzipien einen weiten Raum Sicherheitsarchitekturen zu überdenken und neu zu strukturieren. Zudem kann die räumliche Ausbreitung von Information und Kräften als ein gemeinsames Grundproblem der Entwicklung und Wirksamkeit von Strategien sowohl in der Natur, als auch im Militär identifiziert werden. Die Betrachtung zeigt zudem wie Zellen mit fehlgeleiteten Prozessen und Strukturen umgehen. Die Analogie deutet auf das Erfordernis einer Veränderung im Umgang mit Fehlern und ihrer Rückführ- und Umkehrbarkeit im weitesten Sinne. Das Buch eröffnet überdies ein neues Verständnis von Staat, Gewaltenteilung und Institutionen in einem sozialen System. Die Ergebnisse sind auch auf andere Forschungsbereiche, Organisationen und unterschiedlichste soziale Systeme übertragbar. Es eröffnet sich ein breites Anwendungsspektrum für künftige strategische Untersuchungen. N2 - This book compares strategies of biological systems to military strategies. The central question is directed to whether there are systemic similarities, common or similar structures and similar patterns Processes, for example, both the biological defense mechanism Immune system and in insect societies as well as processes are in the military. KW - Strategie KW - System KW - Militär KW - Netzwerk KW - Biologie KW - strategy KW - system KW - military KW - network KW - biology Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-50068 ER - TY - JOUR A1 - Groth, Detlef T1 - Modeling a secular trend by Monte Carlo simulation of height biased migration in a spatial network JF - Anthropologischer Anzeiger : journal of biological and clinical anthropology ; Mitteilungsorgan der Gesellschaft für Anthropologie N2 - Background: In a recent Monte Carlo simulation, the clustering of body height of Swiss military conscripts within a spatial network with characteristic features of the natural Swiss geography was investigated. In this study I examined the effect of migration of tall individuals into network hubs on the dynamics of body height within the whole spatial network. The aim of this study was to simulate height trends. Material and methods: Three networks were used for modeling, a regular rectangular fishing net like network, a real world example based on the geographic map of Switzerland, and a random network. All networks contained between 144 and 148 districts and between 265-307 road connections. Around 100,000 agents were initially released with average height of 170 cm, and height standard deviation of 6.5 cm. The simulation was started with the a priori assumption that height variation within a district is limited and also depends on height of neighboring districts (community effect on height). In addition to a neighborhood influence factor, which simulates a community effect, body height dependent migration of conscripts between adjacent districts in each Monte Carlo simulation was used to re-calculate next generation body heights. In order to determine the direction of migration for taller individuals, various centrality measures for the evaluation of district importance within the spatial network were applied. Taller individuals were favored to migrate more into network hubs, backward migration using the same number of individuals was random, not biased towards body height. Network hubs were defined by the importance of a district within the spatial network. The importance of a district was evaluated by various centrality measures. In the null model there were no road connections, height information could not be delivered between the districts. Results: Due to the favored migration of tall individuals into network hubs, average body height of the hubs, and later, of the whole network increased by up to 0.1 cm per iteration depending on the network model. The general increase in height within the network depended on connectedness and on the amount of height information that was exchanged between neighboring districts. If higher amounts of neighborhood height information were exchanged, the general increase in height within the network was large (strong secular trend). The trend in the homogeneous fishnet like network was lowest, the trend in the random network was highest. Yet, some network properties, such as the heteroscedasticity and autocorrelations of the migration simulation models differed greatly from the natural features observed in Swiss military conscript networks. Autocorrelations of district heights for instance, were much higher in the migration models. Conclusion: This study confirmed that secular height trends can be modeled by preferred migration of tall individuals into network hubs. However, basic network properties of the migration simulation models differed greatly from the natural features observed in Swiss military conscripts. Similar network-based data from other countries should be explored to better investigate height trends with Monte Carlo migration approach. KW - secular trend KW - body height KW - simulation KW - community effect KW - Monte Carlo method KW - network Y1 - 2017 U6 - https://doi.org/10.1127/anthranz/2017/0703 SN - 0003-5548 SN - 2363-7099 VL - 74 IS - 1 SP - 81 EP - 88 PB - Schweizerbart CY - Stuttgart ER - TY - JOUR A1 - Jelken, Joachim A1 - Santer, Svetlana T1 - Light induced reversible structuring of photosensitive polymer films JF - RSC Advances N2 - In this paper we report on photoswitchable polymer surfaces with dynamically and reversibly fluctuating topographies. It is well known that when azobenzene containing polymer films are irradiated with optical interference patterns the film topography changes to form a surface relief grating. In the simplest case, the film shape mimics the intensity distribution and deforms into a wave like, sinusoidal manner with amplitude that may be as large as the film thickness. This process takes place in the glassy state without photo-induced softening. Here we report on an intriguing discovery regarding the formation of reliefs under special illumination conditions. We have developed a novel setup combining the optical part for creating interference patterns, an AFM for in situ acquisition of topography changes and diffraction efficiency signal measurements. In this way we demonstrate that these gratings can be “set in motion” like water waves or dunes in the desert. We achieve this by applying repetitive polarization changes to the incoming interference pattern. Such light responsive surfaces represent the prerequisite for providing practical applications ranging from conveyer or transport systems for adsorbed liquid objects and colloidal particles to generation of adaptive and dynamic optical devices. KW - surface-relief gratings KW - induced deformation KW - mass-transport KW - azobenzene elastomers KW - thin-films KW - birefringence KW - roughness KW - network KW - erasure Y1 - 2019 U6 - https://doi.org/10.1039/C9RA02571E SN - 2046-2069 VL - 9 IS - 35 SP - 20295 EP - 20305 PB - RSC Publishing CY - London ER - TY - GEN A1 - Jelken, Joachim A1 - Santer, Svetlana T1 - Light induced reversible structuring of photosensitive polymer films T2 - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe N2 - In this paper we report on photoswitchable polymer surfaces with dynamically and reversibly fluctuating topographies. It is well known that when azobenzene containing polymer films are irradiated with optical interference patterns the film topography changes to form a surface relief grating. In the simplest case, the film shape mimics the intensity distribution and deforms into a wave like, sinusoidal manner with amplitude that may be as large as the film thickness. This process takes place in the glassy state without photo-induced softening. Here we report on an intriguing discovery regarding the formation of reliefs under special illumination conditions. We have developed a novel setup combining the optical part for creating interference patterns, an AFM for in situ acquisition of topography changes and diffraction efficiency signal measurements. In this way we demonstrate that these gratings can be “set in motion” like water waves or dunes in the desert. We achieve this by applying repetitive polarization changes to the incoming interference pattern. Such light responsive surfaces represent the prerequisite for providing practical applications ranging from conveyer or transport systems for adsorbed liquid objects and colloidal particles to generation of adaptive and dynamic optical devices. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 750 KW - surface-relief gratings KW - induced deformation KW - mass-transport KW - azobenzene elastomers KW - thin-films KW - birefringence KW - roughness KW - network KW - erasure Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-436432 SN - 1866-8372 IS - 750 SP - 20295 EP - 20305 ER - TY - JOUR A1 - Lehr, Christian A1 - Lischeid, Gunnar T1 - Efficient screening of groundwater head monitoring data for anthropogenic effects and measurement errors JF - Hydrology and Earth System Sciences N2 - Groundwater levels are monitored by environmental agencies to support the sustainable use of groundwater resources. For this purpose continuous and spatially comprehensive monitoring in high spatial and temporal resolution is desired. This leads to large datasets that have to be checked for quality and analysed to distinguish local anthropogenic influences from natural variability of the groundwater level dynamics at each well. Both technical problems with the measurements as well as local anthropogenic influences can lead to local anomalies in the hydrographs. We suggest a fast and efficient screening method for the identification of well-specific peculiarities in hydrographs of groundwater head monitoring networks. The only information required is a set of time series of groundwater heads all measured at the same instants of time. For each well of the monitoring network a reference hydrograph is calculated, describing expected "normal" behaviour at the respective well as is typical for the monitored region. The reference hydrograph is calculated by multiple linear regression of the observed hydrograph with the "stable" principal components (PCs) of a principal component analysis of all groundwater head series of the network as predictor variables. The stable PCs are those PCs which were found in a random subsampling procedure to be rather insensitive to the specific selection of the analysed observation wells, i.e. complete series, and to the specific selection of measurement dates. Hence they can be considered to be representative for the monitored region in the respective period. The residuals of the reference hydrograph describe local deviations from the normal behaviour. Peculiarities in the residuals allow the data to be checked for measurement errors and the wells with a possible anthropogenic influence to be identified. The approach was tested with 141 groundwater head time series from the state authority groundwater monitoring network in northeastern Germany covering the period from 1993 to 2013 at an approximately weekly frequency of measurement. KW - streamflow variability KW - principal components KW - united states KW - time-seriesa KW - water KW - network KW - nonstationarity KW - fluctuations KW - rotation Y1 - 2020 U6 - https://doi.org/10.5194/hess-24-501-2020 SN - 1027-5606 SN - 1607-7938 VL - 24 IS - 2 SP - 501 EP - 513 PB - Copernicus CY - Göttingen ER - TY - GEN A1 - Lehr, Christian A1 - Lischeid, Gunnar T1 - Efficient screening of groundwater head monitoring data for anthropogenic effects and measurement errors T2 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Groundwater levels are monitored by environmental agencies to support the sustainable use of groundwater resources. For this purpose continuous and spatially comprehensive monitoring in high spatial and temporal resolution is desired. This leads to large datasets that have to be checked for quality and analysed to distinguish local anthropogenic influences from natural variability of the groundwater level dynamics at each well. Both technical problems with the measurements as well as local anthropogenic influences can lead to local anomalies in the hydrographs. We suggest a fast and efficient screening method for the identification of well-specific peculiarities in hydrographs of groundwater head monitoring networks. The only information required is a set of time series of groundwater heads all measured at the same instants of time. For each well of the monitoring network a reference hydrograph is calculated, describing expected “normal” behaviour at the respective well as is typical for the monitored region. The reference hydrograph is calculated by multiple linear regression of the observed hydrograph with the “stable” principal components (PCs) of a principal component analysis of all groundwater head series of the network as predictor variables. The stable PCs are those PCs which were found in a random subsampling procedure to be rather insensitive to the specific selection of the analysed observation wells, i.e. complete series, and to the specific selection of measurement dates. Hence they can be considered to be representative for the monitored region in the respective period. The residuals of the reference hydrograph describe local deviations from the normal behaviour. Peculiarities in the residuals allow the data to be checked for measurement errors and the wells with a possible anthropogenic influence to be identified. The approach was tested with 141 groundwater head time series from the state authority groundwater monitoring network in northeastern Germany covering the period from 1993 to 2013 at an approximately weekly frequency of measurement. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1424 KW - streamflow variability KW - principal components KW - united states KW - time-series KW - water KW - network KW - nonstationarity KW - fluctuations KW - rotation Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-511992 SN - 1866-8372 IS - 2 ER -