@phdthesis{Gause2011,
author = {Gause, Clemens},
title = {Das System der Strategie : ein Vergleich zwischen Strategien biologischer Systeme und milit{\"a}rischen Strategien ; eine Modellentwicklung},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-50068},
school = {Universit{\"a}t Potsdam},
year = {2011},
abstract = {Das vorliegende Buch vergleicht Strategien biologischer Systeme mit milit{\"a}rischen Strategien. Die zentrale Fragestellung ist dabei darauf gerichtet, ob es neben systemischen Gemeinsamkeiten auch gemeinsame oder {\"a}hnliche Strukturmuster und {\"a}hnliche Prozessabl{\"a}ufe beispielsweise sowohl im biologischen Abwehrmechanismus des Immunsystems und bei Insektenstaaten als auch bei Prozessen im Milit{\"a}r gibt. Vor diesem Hintergrund klaffen in der Theorie der Strategie, speziell in den Milit{\"a}rwissenschaften L{\"u}cken, denn der Systemansatz wird nicht konsequent beachtet, wie in diesem Buch mehrfach nachgewiesen ist. Von einem allgemeinen Verst{\"a}ndnis 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 erl{\"a}utert. Dabei werden der Begriff der Strategie ebenso wie die Begriffe Struktur und Prozess und Ans{\"a}tze aus der Kriegsphilosophie von Clausewitz untersucht. Den Ausgangspunkt und schließlich auch wieder den Endpunkt der {\"U}berlegungen bilden neben dem notwendigen weiten Verst{\"a}ndnis 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 Abh{\"a}ngigkeit durch strukturelle Kopplung werden beschrieben. Das Zusammenspiel und die daraus entstehende Komplexit{\"a}t der f{\"u}nf Komponenten der Wahrnehmung, der Information und der F{\"u}hrung im Zusammenhang der Komponenten von Raum und Zeit in einem sozialen System lassen die klassische Ziel-Mittel-Zweck-Beziehung Clausewitz´scher Strategiedefinition verk{\"u}rzt 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 Auspr{\"a}gung 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 f{\"u}r den Systemvergleich und kann als Vorgehensmodell k{\"u}nftiger Strategieentwicklung genutzt werden. Der anschließende Systemvergleich wird mit mehreren Beispielen durchgef{\"u}hrt. Ausgehend von der Zelle als Grundeinheit werden Strukturen und Prozesse des Immunsystems mit solchen in milit{\"a}rischen 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 f{\"u}hren zu einem erweiterten Verst{\"a}ndnis der Strategie von Terroristen in sozialen Systemen. Verdeutlicht wird das Grundschema des T{\"a}uschens 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 f{\"u}r neue Ans{\"a}tze f{\"u}r die Organisation von Streitkr{\"a}ften 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 -{\"u}bertragung, die zudem Bypassf{\"a}higkeiten sowie dezentrale Eskalations- und Deeskalationsprinzipien veranschaulichen. Dies er{\"o}ffnet in Analogie dieser Prinzipien einen weiten Raum Sicherheitsarchitekturen zu {\"u}berdenken und neu zu strukturieren. Zudem kann die r{\"a}umliche Ausbreitung von Information und Kr{\"a}ften als ein gemeinsames Grundproblem der Entwicklung und Wirksamkeit von Strategien sowohl in der Natur, als auch im Milit{\"a}r identifiziert werden. Die Betrachtung zeigt zudem wie Zellen mit fehlgeleiteten Prozessen und Strukturen umgehen. Die Analogie deutet auf das Erfordernis einer Ver{\"a}nderung im Umgang mit Fehlern und ihrer R{\"u}ckf{\"u}hr- und Umkehrbarkeit im weitesten Sinne. Das Buch er{\"o}ffnet {\"u}berdies ein neues Verst{\"a}ndnis von Staat, Gewaltenteilung und Institutionen in einem sozialen System. Die Ergebnisse sind auch auf andere Forschungsbereiche, Organisationen und unterschiedlichste soziale Systeme {\"u}bertragbar. Es er{\"o}ffnet sich ein breites Anwendungsspektrum f{\"u}r k{\"u}nftige strategische Untersuchungen.},
language = {de}
}
@article{LehrLischeid2020,
author = {Lehr, Christian and Lischeid, Gunnar},
title = {Efficient screening of groundwater head monitoring data for anthropogenic effects and measurement errors},
series = {Hydrology and Earth System Sciences},
volume = {24},
journal = {Hydrology and Earth System Sciences},
number = {2},
publisher = {Copernicus},
address = {G{\"o}ttingen},
issn = {1027-5606},
doi = {10.5194/hess-24-501-2020},
pages = {501 -- 513},
year = {2020},
abstract = {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.},
language = {en}
}
@misc{LehrLischeid2020,
author = {Lehr, Christian and Lischeid, Gunnar},
title = {Efficient screening of groundwater head monitoring data for anthropogenic effects and measurement errors},
series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
number = {2},
issn = {1866-8372},
doi = {10.25932/publishup-51199},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-511992},
pages = {15},
year = {2020},
abstract = {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.},
language = {en}
}
@article{Distelmeyer2019,
author = {Distelmeyer, Jan},
title = {From object to process},
series = {Artnodes},
journal = {Artnodes},
number = {24},
publisher = {Universitat Oberta de Catalunya},
address = {Barcelona},
issn = {1695-5951},
doi = {10.7238/a.v0i24.3300},
pages = {83 -- 90},
year = {2019},
abstract = {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.},
language = {en}
}
@article{RosenblumPikovsky2023,
author = {Rosenblum, Michael and Pikovsky, Arkady},
title = {Inferring connectivity of an oscillatory network via the phase dynamics reconstruction},
series = {Frontiers in network physiology},
volume = {3},
journal = {Frontiers in network physiology},
publisher = {Frontiers Media},
address = {Lausanne},
issn = {2674-0109},
doi = {10.3389/fnetp.2023.1298228},
pages = {10},
year = {2023},
abstract = {We review an approach for reconstructing oscillatory networks' undirected and directed connectivity from data. The technique relies on inferring the phase dynamics model. The central assumption is that we observe the outputs of all network nodes. We distinguish between two cases. In the first one, the observed signals represent smooth oscillations, while in the second one, the data are pulse-like and can be viewed as point processes. For the first case, we discuss estimating the true phase from a scalar signal, exploiting the protophase-to-phase transformation. With the phases at hand, pairwise and triplet synchronization indices can characterize the undirected connectivity. Next, we demonstrate how to infer the general form of the coupling functions for two or three oscillators and how to use these functions to quantify the directional links. We proceed with a different treatment of networks with more than three nodes. We discuss the difference between the structural and effective phase connectivity that emerges due to high-order terms in the coupling functions. For the second case of point-process data, we use the instants of spikes to infer the phase dynamics model in the Winfree form directly. This way, we obtain the network's coupling matrix in the first approximation in the coupling strength.},
language = {en}
}
@article{FritzMakeyevaStaubetal.2019,
author = {Fritz, Amelie and Makeyeva, Angelina and Staub, Kaspar and Groth, Detlef},
title = {Influence of network properties on a migration induced secular height trend by Monte Carlo simulation},
series = {Journal of biological and clinical anthropology : Anthropologischer Anzeiger ; Mitteilungsorgan der Gesellschaft f{\"u}r Anthropologie},
volume = {76},
journal = {Journal of biological and clinical anthropology : Anthropologischer Anzeiger ; Mitteilungsorgan der Gesellschaft f{\"u}r Anthropologie},
number = {5},
publisher = {Schweizerbart},
address = {Stuttgart},
issn = {0003-5548},
doi = {10.1127/anthranz/2019/1032},
pages = {433 -- 443},
year = {2019},
abstract = {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.},
language = {en}
}
@article{JelkenSanter2019,
author = {Jelken, Joachim and Santer, Svetlana},
title = {Light induced reversible structuring of photosensitive polymer films},
series = {RSC Advances},
volume = {9},
journal = {RSC Advances},
number = {35},
publisher = {RSC Publishing},
address = {London},
issn = {2046-2069},
doi = {10.1039/C9RA02571E},
pages = {20295 -- 20305},
year = {2019},
abstract = {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.},
language = {en}
}
@misc{JelkenSanter2019,
author = {Jelken, Joachim and Santer, Svetlana},
title = {Light induced reversible structuring of photosensitive polymer films},
series = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe},
journal = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe},
number = {750},
issn = {1866-8372},
doi = {10.25932/publishup-43643},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-436432},
pages = {20295 -- 20305},
year = {2019},
abstract = {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.},
language = {en}
}
@article{Groth2017,
author = {Groth, Detlef},
title = {Modeling a secular trend by Monte Carlo simulation of height biased migration in a spatial network},
series = {Anthropologischer Anzeiger : journal of biological and clinical anthropology ; Mitteilungsorgan der Gesellschaft f{\"u}r Anthropologie},
volume = {74},
journal = {Anthropologischer Anzeiger : journal of biological and clinical anthropology ; Mitteilungsorgan der Gesellschaft f{\"u}r Anthropologie},
number = {1},
publisher = {Schweizerbart},
address = {Stuttgart},
issn = {0003-5548},
doi = {10.1127/anthranz/2017/0703},
pages = {81 -- 88},
year = {2017},
abstract = {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.},
language = {en}
}
@misc{Lunemann2006,
type = {Master Thesis},
author = {Lunemann, Carolin},
title = {Quantum cryptography : security analysis of multiuser quantum communication with embedded authentication},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-12756},
school = {Universit{\"a}t Potsdam},
year = {2006},
abstract = {Three quantum cryptographic protocols of multiuser quantum networks with embedded authentication, allowing quantum key distribution or quantum direct communication, are discussed in this work. The security of the protocols against different types of attacks is analysed with a focus on various impersonation attacks and the man-in-the-middle attack. On the basis of the security analyses several improvements are suggested and implemented in order to adjust the investigated vulnerabilities. Furthermore, the impact of the eavesdropping test procedure on impersonation attacks is outlined. The framework of a general eavesdropping test is proposed to provide additional protection against security risks in impersonation attacks.},
language = {en}
}
@article{BinderMettenberger2023,
author = {Binder, Julia and Mettenberger, Tobias},
title = {Schl{\"u}sselfiguren in l{\"a}ndlichen Netzwerken},
series = {KWI-Schriften},
journal = {KWI-Schriften},
number = {14},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-86956-571-2},
issn = {1867-951X},
doi = {10.25932/publishup-63113},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-631133},
pages = {39 -- 50},
year = {2023},
language = {de}
}
@article{BembnistaMettenbergerZscherneck2023,
author = {Bembnista, Kamil and Mettenberger, Tobias and Zscherneck, Julia},
title = {Soziale Netzwerke als Ressourcenzug{\"a}nge f{\"u}r Digitale Pioniere},
series = {KWI-Schriften},
journal = {KWI-Schriften},
number = {14},
publisher = {Universit{\"a}tsverlag Potsdam},
address = {Potsdam},
isbn = {978-3-86956-571-2},
issn = {1867-951X},
doi = {10.25932/publishup-63115},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-631156},
pages = {51 -- 72},
year = {2023},
language = {de}
}
@misc{CrawfordKaramatLehotaietal.2020,
author = {Crawford, Tim and Karamat, Fazeelat and Lehotai, N{\´o}ra and Rentoft, Matilda and Blomberg, Jeanette and Strand, {\AA}sa and Bj{\"o}rklund, Stefan},
title = {Specific functions for mediator complex subunits from different modules in the transcriptional response of arabidopsis thaliana to abiotic stress},
series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
number = {1},
issn = {1866-8372},
doi = {10.25932/publishup-51366},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-513666},
pages = {20},
year = {2020},
abstract = {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.},
language = {en}
}
@article{CrawfordKaramatLehotaietal.2020,
author = {Crawford, Tim and Karamat, Fazeelat and Lehotai, N{\´o}ra and Rentoft, Matilda and Blomberg, Jeanette and Strand, {\AA}sa and Bj{\"o}rklund, Stefan},
title = {Specific functions for mediator complex subunits from different modules in the transcriptional response of arabidopsis thaliana to abiotic stress},
series = {Scientific reports},
volume = {10},
journal = {Scientific reports},
number = {1},
publisher = {Macmillan Publishers Limited, part of Springer Nature},
address = {London},
issn = {2045-2322},
doi = {10.1038/s41598-020-61758-w},
pages = {1 -- 18},
year = {2020},
abstract = {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.},
language = {en}
}
@phdthesis{Stieglitz2008,
author = {Stieglitz, Stefan},
title = {Steuerung Virtueller Communities : Instrumente, Mechanismen, Wirkungszusammenh{\"a}nge},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-16671},
school = {Universit{\"a}t Potsdam},
year = {2008},
abstract = {Virtuelle Communities bezeichnen Gemeinschaften von Individuen, die maßgeblich {\"u}ber das Internet miteinander kommunizieren und kollaborieren. Anders als in Unternehmen, in denen Motivationsstrukturen prim{\"a}r auf finanziellen Anreizen basieren, gilt f{\"u}r Virtuelle Communities, dass die Zuarbeit in diesen in der Regel freiwillig und ohne monet{\"a}re Interessen der Mitglieder stattfindet. Unternehmen nutzen Virtuelle Communities f{\"u}r Zwecke des Customer Relationship Management, des Wissensmanagement und des Customer Integration. Universit{\"a}ten bilden virtuelle Lernnetzwerke, um die Interaktion zwischen Studierenden zu erh{\"o}hen und hierdurch Lernerfolge zu steigern. Die Potenziale Virtueller Communities werden jedoch in vielen F{\"a}llen nicht vollst{\"a}ndig ausgesch{\"o}pft. Insbesondere der Frage nach einer systematischen Mitgliedersteuerung kommt aufgrund der vorherrschenden komplexen Motivationsstrukturen der freiwillig partizipierenden Mitglieder eine besondere Bedeutung zu. In bisherigen wissenschaftlichen Arbeiten wurde dieser Aspekt jedoch vernachl{\"a}ssigt. Das Untersuchungsdesign der Arbeit zielt darauf ab, diese Forschungsl{\"u}cke zu schließen und einen Ordnungsrahmen zu gestalten, der einen systematischen Aufbau, Betrieb und insbesondere eine Steuerung Virtueller Communities erm{\"o}glicht. Die Identifikation von Steuerungsinstrumenten wurde im Rahmen der Arbeit durch eine Analyse der Strukturen und Funktionsweisen in Open Source-Projekten vorgenommen, anschließend wurden diese auf andere Typen Virtueller Communities {\"u}bertragen. Im Rahmen zweier Fallstudien wurde der entwickelte Ordnungsrahmen unter realen Bedingungen an einem Expertennetzwerk an der B{\"o}rse Berlin AG und einem universit{\"a}ren Lernnetzwerk erprobt. Die anschließende Analyse gibt Aufschluss {\"u}ber die Wirkungsweisen wettbewerblicher, kooperativer und hierarchischer Steuerungsinstrumente in Virtuellen Communities.},
language = {de}
}
@article{StollenwerkDoerflerSchibberges2016,
author = {Stollenwerk, Eric and D{\"o}rfler, Thomas and Schibberges, Julian},
title = {Taking a new perspective},
series = {Terrorism and political violence},
volume = {28},
journal = {Terrorism and political violence},
number = {5},
publisher = {Taylor \& Francis},
address = {London},
issn = {0954-6553},
doi = {10.1080/09546553.2014.987341},
pages = {950 -- 970},
year = {2016},
abstract = {Network analysis has attracted significant attention when researching the phenomenon of transnational terrorism, particularly Al Qaeda. While many scholars have made valuable contributions to mapping Al Qaeda, several problems remain due to a lack of data and the omission of data provided by international organizations such as the UN. Thus, this article applies a social network analysis and subsequent mappings of the data gleaned from the Security Council's consolidated sanctions list, and asks what they can demonstrate about the structure and organizational characteristics of Al Qaeda. The study maps the Al Qaeda network on a large scale using a newly compiled data set. The analysis reveals that the Al Qaeda network consists of several hundred individual and group nodes connecting almost all over the globe. Several major nodes are crucial for the network structure, while simultaneously many other nodes only weakly and foremost regionally connect to the network. The article concludes that the findings tie in well to the latest research pointing to local and simultaneously global elements of Al Qaeda, and that the new data is a valuable source for further analyses, potentially in combination with other data.},
language = {en}
}
@article{WilhelmiGrunwaldGimberetal.2020,
author = {Wilhelmi, Ilka and Grunwald, Stephan and Gimber, Niclas and Popp, Oliver and Dittmar, Gunnar and Arumughan, Anup and Wanker, Erich E. and Laeger, Thomas and Schmoranzer, Jan and Daumke, Oliver and Sch{\"u}rmann, Annette},
title = {The ARFRP1-dependent Golgi scaffolding protein GOPC is required for insulin secretion from pancreatic 13-cells},
series = {Molecular metabolism},
volume = {45},
journal = {Molecular metabolism},
publisher = {Elsevier},
address = {Amsterdam},
issn = {2212-8778},
doi = {10.1016/j.molmet.2020.101151},
pages = {13},
year = {2020},
abstract = {Objective: Hormone secretion from metabolically active tissues, such as pancreatic islets, is governed by specific and highly regulated signaling pathways. Defects in insulin secretion are among the major causes of diabetes. The molecular mechanisms underlying regulated insulin secretion are, however, not yet completely understood. In this work, we studied the role of the GTPase ARFRP1 on insulin secretion from pancreatic 13-cells.
Methods: A 13-cell-specific Arfrp1 knockout mouse was phenotypically characterized. Pulldown experiments and mass spectrometry analysis were employed to screen for new ARFRP1-interacting proteins. Co-immunoprecipitation assays as well as super-resolution microscopy were applied for validation.
Results: The GTPase ARFRP1 interacts with the Golgi-associated PDZ and coiled-coil motif-containing protein (GOPC). Both proteins are co localized at the trans-Golgi network and regulate the first and second phase of insulin secretion by controlling the plasma membrane localization of the SNARE protein SNAP25. Downregulation of both GOPC and ARFRP1 in Min6 cells interferes with the plasma membrane localization of SNAP25 and enhances its degradation, thereby impairing glucose-stimulated insulin release from 13-cells. In turn, overexpression of SNAP25 as well as GOPC restores insulin secretion in islets from 13-cell-specific Arfrp1 knockout mice.
Conclusion: Our results identify a hitherto unrecognized pathway required for insulin secretion at the level of trans-Golgi sorting. (c) 2020 The Authors. Published by Elsevier GmbH. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).},
language = {en}
}