@misc{VoltmerKieschkeSchwappachetal.2008, author = {Voltmer, Edgar and Kieschke, Ulf and Schwappach, David L.B. and Wirsching, Michael and Spahn, Claudia}, title = {Psychosocial health risk factors and resources of medical students and physicians}, series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, number = {641}, issn = {1866-8364}, doi = {10.25932/publishup-43121}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-431211}, pages = {11}, year = {2008}, abstract = {Background Epidemiological data indicate elevated psychosocial health risks for physicians, e.g., burnout, depression, marital disturbances, alcohol and substance abuse, and suicide. The purpose of this study was to identify psychosocial health resources and risk factors in profession-related behaviour and experience patterns of medical students and physicians that may serve as a basis for appropriate health promoting interventions. Methods The questionnaire -Related Behaviour and Experience "Work administered in cross-sectional surveys to students in the first (n = 475) and in the fifth year of studies (n = 355) in required courses at three German universities and to physicians in early professional life in the vicinity of these universities (n = 381). Results Scores reflecting a healthy behaviour pattern were less likely in physicians (16.7\%) compared to 5th year (26.0\%) and 1st year students (35.1\%) while scores representing unambitious and resigned patterns were more common among physicians (43.4\% vs. 24.4\% vs. 41.0\% and 27.3\% vs. 17.2\% vs. 23.3 respectively). Female and male responders differed in the domains professional commitment, resistance to stress and emotional well-being. Female physicians on average scored higher in the dimensions resignation tendencies, satisfaction with life and experience of social support, and lower in career ambition. Conclusion The results show distinct psychosocial stress patterns among medical students and physicians. Health promotion and prevention of psychosocial symptoms and impairments should be integrated as a required part of the medical curriculum and be considered an important issue during the further training of physicians.}, language = {en} } @misc{YangTangZhuetal.2008, author = {Yang, Lei and Tang, Renjie and Zhu, Jinqi and Liu, Hua and Mueller-Roeber, Bernd and Xia, Huijun and Zhang, Hongxia}, title = {Enhancement of stress tolerance in transgenic tobacco plants constitutively expressing AtIpk2β, an inositol polyphosphate 6-/3-kinase from Arabidopsis thaliana}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {954}, issn = {1866-8372}, doi = {10.25932/publishup-43122}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-431225}, pages = {17}, year = {2008}, abstract = {Inositol phosphates (IPs) and their turnover products have been implicated to play important roles in stress signaling in eukaryotic cells. In higher plants genes encoding inositol polyphosphate kinases have been identified previously, but their physiological functions have not been fully resolved. Here we expressed Arabidopsis inositol polyphosphate 6-/3-kinase (AtIpk2 beta) in two heterologous systems, i.e. the yeast Saccharomyces cerevisiae and in tobacco (Nicotiana tabacum), and tested the effect on abiotic stress tolerance. Expression of AtIpk2 beta rescued the salt-, osmotic- and temperature-sensitive growth defects of a yeast mutant strain (arg82 Delta) that lacks inositol polyphosphate multikinase activity encoded by the ARG82/IPK2 gene. Transgenic tobacco plants constitutively expressing AtIpk2 beta under the control of the Cauliflower Mosaic Virus 35S promoter were generated and found to exhibit improved tolerance to diverse abiotic stresses when compared to wild type plants. Expression patterns of various stress responsive genes were enhanced, and the activities of anti-oxidative enzymes were elevated in transgenic plants, suggesting a possible involvement of AtIpk2 beta in plant stress responses.}, language = {en} } @misc{AndorfGaertnerSteinfathetal.2008, author = {Andorf, Sandra and G{\"a}rtner, Tanja and Steinfath, Matthias and Witucka-Wall, Hanna and Altmann, Thomas and Repsilber, Dirk}, title = {Towards systems biology of heterosis}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {949}, issn = {1866-8372}, doi = {10.25932/publishup-43627}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-436274}, pages = {14}, year = {2008}, abstract = {We propose a network structure-based model for heterosis, and investigate it relying on metabolite profiles from Arabidopsis. A simple feed-forward two-layer network model (the Steinbuch matrix) is used in our conceptual approach. It allows for directly relating structural network properties with biological function. Interpreting heterosis as increased adaptability, our model predicts that the biological networks involved show increasing connectivity of regulatory interactions. A detailed analysis of metabolite profile data reveals that the increasing-connectivity prediction is true for graphical Gaussian models in our data from early development. This mirrors properties of observed heterotic Arabidopsis phenotypes. Furthermore, the model predicts a limit for increasing hybrid vigor with increasing heterozygosity—a known phenomenon in the literature.}, language = {en} } @misc{ArvidssonKwasniewskiRianoPachonetal.2008, author = {Arvidsson, Samuel Janne and Kwasniewski, Miroslaw and Ria{\~n}o- Pach{\´o}n, Diego Mauricio and Mueller-Roeber, Bernd}, title = {QuantPrime}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {943}, issn = {1866-8372}, doi = {10.25932/publishup-43153}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-431531}, pages = {17}, year = {2008}, abstract = {Background Medium- to large-scale expression profiling using quantitative polymerase chain reaction (qPCR) assays are becoming increasingly important in genomics research. A major bottleneck in experiment preparation is the design of specific primer pairs, where researchers have to make several informed choices, often outside their area of expertise. Using currently available primer design tools, several interactive decisions have to be made, resulting in lengthy design processes with varying qualities of the assays. Results Here we present QuantPrime, an intuitive and user-friendly, fully automated tool for primer pair design in small- to large-scale qPCR analyses. QuantPrime can be used online through the internet http://www.quantprime.de/ or on a local computer after download; it offers design and specificity checking with highly customizable parameters and is ready to use with many publicly available transcriptomes of important higher eukaryotic model organisms and plant crops (currently 295 species in total), while benefiting from exon-intron border and alternative splice variant information in available genome annotations. Experimental results with the model plant Arabidopsis thaliana, the crop Hordeum vulgare and the model green alga Chlamydomonas reinhardtii show success rates of designed primer pairs exceeding 96\%. Conclusion QuantPrime constitutes a flexible, fully automated web application for reliable primer design for use in larger qPCR experiments, as proven by experimental data. The flexible framework is also open for simple use in other quantification applications, such as hydrolyzation probe design for qPCR and oligonucleotide probe design for quantitative in situ hybridization. Future suggestions made by users can be easily implemented, thus allowing QuantPrime to be developed into a broad-range platform for the design of RNA expression assays.}, language = {en} } @misc{KaastraPaerelsDurretetal.2008, author = {Kaastra, Jelle S. and Paerels, Frits B.S. and Durret, Florence and Schindler, Sabine and Richter, Philipp}, title = {Thermal radiation processes}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, number = {891}, issn = {1866-8372}, doi = {10.25932/publishup-43622}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-436220}, pages = {155 -- 190}, year = {2008}, abstract = {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.}, language = {en} } @misc{HartmannVision2008, author = {Hartmann, Stefanie and Vision, Todd J.}, title = {Using ESTs for phylogenomics}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, number = {889}, issn = {1866-8372}, doi = {10.25932/publishup-43667}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-436670}, pages = {15}, year = {2008}, abstract = {Background While full genome sequences are still only available for a handful of taxa, large collections of partial gene sequences are available for many more. The alignment of partial gene sequences results in a multiple sequence alignment containing large gaps that are arranged in a staggered pattern. The consequences of this pattern of missing data on the accuracy of phylogenetic analysis are not well understood. We conducted a simulation study to determine the accuracy of phylogenetic trees obtained from gappy alignments using three commonly used phylogenetic reconstruction methods (Neighbor Joining, Maximum Parsimony, and Maximum Likelihood) and studied ways to improve the accuracy of trees obtained from such datasets. Results We found that the pattern of gappiness in multiple sequence alignments derived from partial gene sequences substantially compromised phylogenetic accuracy even in the absence of alignment error. The decline in accuracy was beyond what would be expected based on the amount of missing data. The decline was particularly dramatic for Neighbor Joining and Maximum Parsimony, where the majority of gappy alignments contained 25\% to 40\% incorrect quartets. To improve the accuracy of the trees obtained from a gappy multiple sequence alignment, we examined two approaches. In the first approach, alignment masking, potentially problematic columns and input sequences are excluded from from the dataset. Even in the absence of alignment error, masking improved phylogenetic accuracy up to 100-fold. However, masking retained, on average, only 83\% of the input sequences. In the second approach, alignment subdivision, the missing data is statistically modelled in order to retain as many sequences as possible in the phylogenetic analysis. Subdivision resulted in more modest improvements to alignment accuracy, but succeeded in including almost all of the input sequences. Conclusion These results demonstrate that partial gene sequences and gappy multiple sequence alignments can pose a major problem for phylogenetic analysis. The concern will be greatest for high-throughput phylogenomic analyses, in which Neighbor Joining is often the preferred method due to its computational efficiency. Both approaches can be used to increase the accuracy of phylogenetic inference from a gappy alignment. The choice between the two approaches will depend upon how robust the application is to the loss of sequences from the input set, with alignment masking generally giving a much greater improvement in accuracy but at the cost of discarding a larger number of the input sequences.}, language = {en} } @misc{BaurHirschmuellerJahnetal.2008, author = {Baur, Heiner and Hirschm{\"u}ller, Anja and Jahn, Michael and M{\"u}ller, Steffen and Mayer, Frank}, title = {Therapeutic efficiency and biomechanical effects of sport insoles in female runners}, series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, number = {624}, issn = {1866-8364}, doi = {10.25932/publishup-43552}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-435525}, pages = {4}, year = {2008}, language = {en} } @misc{NeigenfindGyetvaiBasekowetal.2008, author = {Neigenfind, Jost and Gyetvai, Gabor and Basekow, Rico and Diehl, Svenja and Achenbach, Ute and Gebhardt, Christiane and Selbig, Joachim and Kersten, Birgit}, title = {Haplotype inference from unphased SNP data in heterozygous polyploids based on SAT}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, number = {883}, issn = {1866-8372}, doi = {10.25932/publishup-43501}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-435011}, pages = {28}, year = {2008}, abstract = {Background: Haplotype inference based on unphased SNP markers is an important task in population genetics. Although there are different approaches to the inference of haplotypes in diploid species, the existing software is not suitable for inferring haplotypes from unphased SNP data in polyploid species, such as the cultivated potato (Solanum tuberosum). Potato species are tetraploid and highly heterozygous. Results: Here we present the software SATlotyper which is able to handle polyploid and polyallelic data. SATlo-typer uses the Boolean satisfiability problem to formulate Haplotype Inference by Pure Parsimony. The software excludes existing haplotype inferences, thus allowing for calculation of alternative inferences. As it is not known which of the multiple haplotype inferences are best supported by the given unphased data set, we use a bootstrapping procedure that allows for scoring of alternative inferences. Finally, by means of the bootstrapping scores, it is possible to optimise the phased genotypes belonging to a given haplotype inference. The program is evaluated with simulated and experimental SNP data generated for heterozygous tetraploid populations of potato. We show that, instead of taking the first haplotype inference reported by the program, we can significantly improve the quality of the final result by applying additional methods that include scoring of the alternative haplotype inferences and genotype optimisation. For a sub-population of nineteen individuals, the predicted results computed by SATlotyper were directly compared with results obtained by experimental haplotype inference via sequencing of cloned amplicons. Prediction and experiment gave similar results regarding the inferred haplotypes and phased genotypes. Conclusion: Our results suggest that Haplotype Inference by Pure Parsimony can be solved efficiently by the SAT approach, even for data sets of unphased SNP from heterozygous polyploids. SATlotyper is freeware and is distributed as a Java JAR file. The software can be downloaded from the webpage of the GABI Primary Database at http://www.gabipd.org/projects/satlotyper/. The application of SATlotyper will provide haplotype information, which can be used in haplotype association mapping studies of polyploid plants.}, language = {en} } @misc{LamprechtMargariaSteffenetal.2008, author = {Lamprecht, Anna-Lena and Margaria, Tiziana and Steffen, Bernhard and Sczyrba, Alexander and Hartmeier, Sven and Giegerich, Robert}, title = {GeneFisher-P}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {868}, issn = {1866-8372}, doi = {10.25932/publishup-43424}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-434241}, pages = {17}, year = {2008}, abstract = {Background: PCR primer design is an everyday, but not trivial task requiring state-of-the-art software. We describe the popular tool GeneFisher and explain its recent restructuring using workflow techniques. We apply a service-oriented approach to model and implement GeneFisher-P, a process-based version of the GeneFisher web application, as a part of the Bio-jETI platform for service modeling and execution. We show how to introduce a flexible process layer to meet the growing demand for improved user-friendliness and flexibility. Results: Within Bio-jETI, we model the process using the jABC framework, a mature model-driven, service-oriented process definition platform. We encapsulate remote legacy tools and integrate web services using jETI, an extension of the jABC for seamless integration of remote resources as basic services, ready to be used in the process. Some of the basic services used by GeneFisher are in fact already provided as individual web services at BiBiServ and can be directly accessed. Others are legacy programs, and are made available to Bio-jETI via the jETI technology. The full power of service-based process orientation is required when more bioinformatics tools, available as web services or via jETI, lead to easy extensions or variations of the basic process. This concerns for instance variations of data retrieval or alignment tools as provided by the European Bioinformatics Institute (EBI). Conclusions: The resulting service-and process-oriented GeneFisher-P demonstrates how basic services from heterogeneous sources can be easily orchestrated in the Bio-jETI platform and lead to a flexible family of specialized processes tailored to specific tasks.}, language = {en} } @misc{GinouxHabib2008, author = {Ginoux, Nicolas and Habib, Georges}, title = {Geometric aspects of transversal Killing spinors on Riemannian flows}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, number = {867}, issn = {1866-8372}, doi = {10.25932/publishup-43478}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-434783}, pages = {69 -- 90}, year = {2008}, abstract = {We study a Killing spinor type equation on spin Riemannian flows. We prove integrability conditions and partially classify those flows carrying non-trivial solutions.}, language = {en} } @misc{RichterPaerelsKaastra2008, author = {Richter, Philipp and Paerels, Frits B. S. and Kaastra, Jelle S.}, title = {FUV and X-Ray absorption in the warm-hot intergalactic medium}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, number = {864}, issn = {1866-8372}, doi = {10.25932/publishup-43422}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-434226}, pages = {25 -- 49}, year = {2008}, abstract = {The Warm-Hot Intergalactic Medium (WHIM) arises from shock-heated gas collapsing in large-scale filaments and probably harbours a substantial fraction of the baryons in the local Universe. Absorption-line measurements in the ultraviolet (UV) and in the X-ray band currently represent the best method to study the WHIM at low redshifts. We here describe the physical properties of the WHIM and the concepts behind WHIM absorption line measurements of Hi and high ions such as Ovi, Ovii, and Oviii in the far-ultraviolet and X-ray band. We review results of recent WHIM absorption line studies carried out with UV and X-ray satellites such as FUSE, HST, Chandra, and XMM-Newton and discuss their implications for our knowledge of the WHIM.}, language = {en} } @misc{PaerelsKaastraOhashietal.2008, author = {Paerels, Frits and Kaastra, Jelle and Ohashi, Takaya and Richter, Philipp and Bykov, Andrei and Nevalainen, Jukka}, title = {Future instrumentation for the study of the warm-hot intergalactic medium}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, number = {859}, issn = {1866-8372}, doi = {10.25932/publishup-43405}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-434057}, pages = {405 -- 418}, year = {2008}, abstract = {We briefly review capabilities and requirements for future instrumentation in UV- and X-ray astronomy that can contribute to advancing our understanding of the diffuse, highly ionised intergalactic medium.}, language = {en} } @misc{LiesenjohannEccard2008, author = {Liesenjohann, Thilo and Eccard, Jana}, title = {Foraging under uniform risk from different types of predators}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, number = {858}, issn = {1866-8372}, doi = {10.25932/publishup-43293}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-432932}, pages = {11}, year = {2008}, abstract = {Background Many animals live in environments where different types of predators pose a permanent threat and call for predator specific strategies. When foraging, animals have to balance the competing needs of food and safety in order to survive. While animals sometimes can choose between microhabitats that differ in their risk of predation, many habitats are uniform in their risk distribution. So far, little is known about adaptive antipredator behavior under uniform risk. We simulated two predator types, avian and mammalian, each representing a spatially uniform risk in the artificial resource landscapes. Voles served as experimental foragers. Results Animals were exposed to factorial combinations of weasel odour and ground cover to simulate avian and/or mammalian predation. We measured short and long term responses with video analysis and giving-up densities. The results show that previously experienced conditions cause delayed effects. After these effects ceased, the risks of both types of predation caused a reduction in food intake. Avian predation induced a concentration on a smaller number of feeding patches. While higher avian risk caused a delay in activity, the weasel odour shortened the latency until the voles started to be active. Conclusion We show that the voles differed in risk types and adjusted their feeding strategies accordingly. Responses to avian and mammalian risk differed both in strength and time scales. Uniformity of risk resulted in a concentration of foraging investment and lower foraging efficiency.}, language = {en} } @misc{WoerheideEppMacis2008, author = {W{\"o}rheide, Gert and Epp, Laura Saskia and Macis, Luciana}, title = {Deep genetic divergences among Indo-Pacific populations of the coral reef sponge Leucetta chagosensis (Leucettidae)}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, number = {846}, issn = {1866-8372}, doi = {10.25932/publishup-43012}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-430121}, pages = {20}, year = {2008}, abstract = {Background: An increasing number of studies demonstrate that genetic differentiation and speciation in the sea occur over much smaller spatial scales than previously appreciated given the wide distribution range of many morphologically defined coral reef invertebrate species and the presumed dispersal-enhancing qualities of ocean currents. However, knowledge about the processes that lead to population divergence and speciation is often lacking despite being essential for the understanding, conservation, and management of marine biodiversity. Sponges, a highly diverse, ecologically and economically important reef-invertebrate taxon, exhibit spatial trends in the Indo-West Pacific that are not universally reflected in other marine phyla. So far, however, processes generating those unexpected patterns are not understood. Results: We unraveled the phylogeographic structure of the widespread Indo-Pacific coral reef sponge Leucetta chagosensis across its known geographic range using two nuclear markers: the rDNA internal transcribed spacers (ITS 1\&2) and a fragment of the 28S gene, as well as the second intron of the ATP synthetase beta subunit-gene (ATPSb-iII). This enabled the detection of several deeply divergent clades congruent over both loci, one containing specimens from the Indian Ocean ( Red Sea and Maldives), another one from the Philippines, and two other large and substructured NW Pacific and SW Pacific clades with an area of overlap in the Great Barrier Reef/Coral Sea. Reciprocally monophyletic populations were observed from the Philippines, Red Sea, Maldives, Japan, Samoa, and Polynesia, demonstrating long-standing isolation. Populations along the South Equatorial Current in the south-western Pacific showed isolation-by-distance effects. Overall, the results pointed towards stepping-stone dispersal with some putative long-distance exchange, consistent with expectations from low dispersal capabilities. Conclusion: We argue that both founder and vicariance events during the late Pliocene and Pleistocene were responsible to varying degrees for generating the deep phylogeographic structure. This structure was perpetuated largely as a result of the life history of L. chagosensis, resulting in high levels of regional isolation. Reciprocally monophyletic populations constitute putative sibling ( cryptic) species, while population para- and polyphyly may indicate incipient speciation processes. The genetic diversity and biodiversity of tropical Indo-Pacific sponges appears to be substantially underestimated since the high level of genetic divergence is not necessarily manifested at the morphological level.}, language = {en} } @misc{DworschakGrellNikiforovaetal.2008, author = {Dworschak, Steve and Grell, Susanne and Nikiforova, Victoria J. and Schaub, Torsten H. and Selbig, Joachim}, title = {Modeling biological networks by action languages via answer set programming}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, number = {843}, issn = {1866-8372}, doi = {10.25932/publishup-42984}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-429846}, pages = {47}, year = {2008}, abstract = {We describe an approach to modeling biological networks by action languages via answer set programming. To this end, we propose an action language for modeling biological networks, building on previous work by Baral et al. We introduce its syntax and semantics along with a translation into answer set programming, an efficient Boolean Constraint Programming Paradigm. Finally, we describe one of its applications, namely, the sulfur starvation response-pathway of the model plant Arabidopsis thaliana and sketch the functionality of our system and its usage.}, language = {en} } @misc{SchmidtBaumannWalz2008, author = {Schmidt, Ruth and Baumann, Otto and Walz, Bernd}, title = {cAMP potentiates InsP3-induced Ca2+ release from the endoplasmic reticulum in blowfly salivary glands}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, number = {842}, issn = {1866-8372}, doi = {10.25932/publishup-42977}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-429770}, pages = {13}, year = {2008}, abstract = {Background Serotonin induces fluid secretion from Calliphora salivary glands by the parallel activation of the InsP3/Ca2+ and cAMP signaling pathways. We investigated whether cAMP affects 5-HT-induced Ca2+ signaling and InsP3-induced Ca2+ release from the endoplasmic reticulum (ER). Results Increasing intracellular cAMP level by bath application of forskolin, IBMX or cAMP in the continuous presence of threshold 5-HT concentrations converted oscillatory [Ca2+]i changes into a sustained increase. Intraluminal Ca2+ measurements in the ER of ß-escin-permeabilized glands with mag-fura-2 revealed that cAMP augmented InsP3-induced Ca2+ release in a concentration-dependent manner. This indicated that cAMP sensitized the InsP3 receptor Ca2+ channel for InsP3. By using cAMP analogs that activated either protein kinase A (PKA) or Epac and the application of PKA-inhibitors, we found that cAMP-induced augmentation of InsP3-induced Ca2+ release was mediated by PKA not by Epac. Recordings of the transepithelial potential of the glands suggested that cAMP sensitized the InsP3/Ca2+ signaling pathway for 5-HT, because IBMX potentiated Ca2+-dependent Cl- transport activated by a threshold 5-HT concentration. Conclusion This report shows, for the first time for an insect system, that cAMP can potentiate InsP3-induced Ca2+ release from the ER in a PKA-dependent manner, and that this crosstalk between cAMP and InsP3/Ca2+ signaling pathways enhances transepithelial electrolyte transport.}, language = {en} } @misc{KoehlBaslerLuedemannetal.2008, author = {K{\"o}hl, Karin I. and Basler, Georg and L{\"u}demann, Alexander and Selbig, Joachim and Walther, Dirk}, title = {A plant resource and experiment management system based on the Golm Plant Database as a basic tool for omics research}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, number = {830}, doi = {10.25932/publishup-42759}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-427595}, pages = {13}, year = {2008}, abstract = {Background: For omics experiments, detailed characterisation of experimental material with respect to its genetic features, its cultivation history and its treatment history is a requirement for analyses by bioinformatics tools and for publication needs. Furthermore, meta-analysis of several experiments in systems biology based approaches make it necessary to store this information in a standardised manner, preferentially in relational databases. In the Golm Plant Database System, we devised a data management system based on a classical Laboratory Information Management System combined with web-based user interfaces for data entry and retrieval to collect this information in an academic environment. Results: The database system contains modules representing the genetic features of the germplasm, the experimental conditions and the sampling details. In the germplasm module, genetically identical lines of biological material are generated by defined workflows, starting with the import workflow, followed by further workflows like genetic modification (transformation), vegetative or sexual reproduction. The latter workflows link lines and thus create pedigrees. For experiments, plant objects are generated from plant lines and united in so-called cultures, to which the cultivation conditions are linked. Materials and methods for each cultivation step are stored in a separate ACCESS database of the plant cultivation unit. For all cultures and thus every plant object, each cultivation site and the culture's arrival time at a site are logged by a barcode-scanner based system. Thus, for each plant object, all site-related parameters, e. g. automatically logged climate data, are available. These life history data and genetic information for the plant objects are linked to analytical results by the sampling module, which links sample components to plant object identifiers. This workflow uses controlled vocabulary for organs and treatments. Unique names generated by the system and barcode labels facilitate identification and management of the material. Web pages are provided as user interfaces to facilitate maintaining the system in an environment with many desktop computers and a rapidly changing user community. Web based search tools are the basis for joint use of the material by all researchers of the institute. Conclusion: The Golm Plant Database system, which is based on a relational database, collects the genetic and environmental information on plant material during its production or experimental use at the Max-Planck-Institute of Molecular Plant Physiology. It thus provides information according to the MIAME standard for the component 'Sample' in a highly standardised format. The Plant Database system thus facilitates collaborative work and allows efficient queries in data analysis for systems biology research.}, language = {en} } @misc{MargariaKubczakSteffen2008, author = {Margaria, Tiziana and Kubczak, Christian and Steffen, Bernhard}, title = {Bio-jETI}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {822}, doi = {10.25932/publishup-42886}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-428868}, pages = {19}, year = {2008}, abstract = {Background: With Bio-jETI, we introduce a service platform for interdisciplinary work on biological application domains and illustrate its use in a concrete application concerning statistical data processing in R and xcms for an LC/MS analysis of FAAH gene knockout. Methods: Bio-jETI uses the jABC environment for service-oriented modeling and design as a graphical process modeling tool and the jETI service integration technology for remote tool execution. Conclusions: As a service definition and provisioning platform, Bio-jETI has the potential to become a core technology in interdisciplinary service orchestration and technology transfer. Domain experts, like biologists not trained in computer science, directly define complex service orchestrations as process models and use efficient and complex bioinformatics tools in a simple and intuitive way.}, language = {en} } @misc{Eckstein2008, author = {Eckstein, Lars}, title = {The pitfalls of picturing atlantic slavery : Steven Spielbergs Amistad vs. Guy Deslauriers's Middle Passage}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-59422}, year = {2008}, language = {en} } @misc{Kliegl2008, author = {Kliegl, Reinhold}, title = {Publication Statistics Show Collaboration, Not Competition}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-57198}, year = {2008}, language = {en} } @misc{BostonHaleKliegletal.2008, author = {Boston, Marisa Ferrara and Hale, John and Kliegl, Reinhold and Patil, Umesh and Vasishth, Shravan}, title = {Parsing costs as predictors of reading difficulty: An evaluation using the Potsdam Sentence Corpus}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-57139}, year = {2008}, abstract = {The surprisal of a word on a probabilistic grammar constitutes a promising complexity metric for human sentence comprehension difficulty. Using two different grammar types, surprisal is shown to have an effect on fixation durations and regression probabilities in a sample of German readers' eye movements, the Potsdam Sentence Corpus. A linear mixed-effects model was used to quantify the effect of surprisal while taking into account unigram and bigram frequency, word length, and empirically-derived word predictability; the so-called "early" and "late" measures of processing difficulty both showed an effect of surprisal. Surprisal is also shown to have a small but statistically non-significant effect on empirically-derived predictability itself. This work thus demonstrates the importance of including parsing costs as a predictor of comprehension difficulty in models of reading, and suggests that a simple identification of syntactic parsing costs with early measures and late measures with durations of post-syntactic events may be difficult to uphold.}, language = {en} } @misc{AngeleSlatteryYangetal.2008, author = {Angele, Bernhard and Slattery, Timothy J. and Yang, Jinmian and Kliegl, Reinhold and Rayner, Keith}, title = {Parafoveal processing in reading: Manipulating n+1 and n+2 previews simultaneously}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-57128}, year = {2008}, abstract = {The boundary paradigm (Rayner, 1975) with a novel preview manipulation was used to examine the extent of parafoveal processing of words to the right of fixation. Words n+1 and n+2 had either correct or incorrect previews prior to fixation (prior to crossing the boundary location). In addition, the manipulation utilized either a high or low frequency word in word n+1 location on the assumption that it would be more likely that n+2 preview effects could be obtained when word n+1 was high frequency. The primary findings were that there was no evidence for a preview benefit for word n+2 and no evidence for parafoveal-on-foveal effects when word n+1 is at least four letters long. We discuss implications for models of eye-movement control in reading.}, language = {en} } @misc{OngKliegl2008, author = {Ong, James Kwan Yau and Kliegl, Reinhold}, title = {Conditional co-occurrence probability acts like frequency in predicting fixation durations}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-56771}, year = {2008}, abstract = {The predictability of an upcoming word has been found to be a useful predictor in eye movement research, but is expensive to collect and subjective in nature. It would be desirable to have other predictors that are easier to collect and objective in nature if these predictors were capable of capturing the information stored in predictability. This paper contributes to this discussion by testing a possible predictor: conditional co-occurrence probability. This measure is a simple statistical representation of the relatedness of the current word to its context, based only on word co-occurrence patterns in data taken from the Internet. In the regression analyses, conditional co-occurrence probability acts like lexical frequency in predicting fixation durations, and its addition does not greatly improve the model fits. We conclude that readers do not seem to use the information contained within conditional co-occurrence probability during reading for meaning, and that similar simple measures of semantic relatedness are unlikely to be able to replace predictability as a predictor for fixation durations. Keywords: Co-occurrence probability, Cloze predictability, frequency, eye movement, fixation duration.}, language = {en} } @misc{ReinVossBlenauetal.2008, author = {Rein, Julia and Voss, Martin and Blenau, Wolfgang and Walz, Bernd and Baumann, Otto}, title = {Hormone-induced assembly and activation of V-ATPase in blowfly salivary glands is mediated by protein kinase A}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-46126}, year = {2008}, abstract = {The vacuolar H+-ATPase (V-ATPase) in the apical membrane of blowfly (Calliphora vicina) salivary gland cells energizes the secretion of a KCl-rich saliva in response to the neurohormone serotonin (5-HT). We have shown previously that exposure to 5-HT induces a cAMP-mediated reversible assembly of V-0 and V-1 subcomplexes to V-ATPase holoenzymes and increases V-ATPase-driven proton transport. Here, we analyze whether the effect of cAMP on V-ATPase is mediated by protein kinase A (PKA) or exchange protein directly activated by cAMP (Epac), the cAMP target proteins that are present within the salivary glands. Immunofluorescence microscopy shows that PKA activators, but not Epac activators, induce the translocation of V1 components from the cytoplasm to the apical membrane, indicative of an assembly of V-ATPase holoenzymes. Measurements of transepithelial voltage changes and microfluorometric pH measurements at the luminal surface of cells in isolated glands demonstrate further that PKA-activating cAMP analogs increase cation transport to the gland lumen and induce a V-ATPase-dependent luminal acidification, whereas activators of Epac do not. Inhibitors of PKA block the 5-HT-induced V-1 translocation to the apical membrane and the increase in proton transport. We conclude that cAMP exerts its effects on V-ATPase via PKA.}, language = {en} } @misc{PatilKentnerGollradetal.2008, author = {Patil, Umesh and Kentner, Gerrit and Gollrad, Anja and K{\"u}gler, Frank and F{\´e}ry, Caroline and Vasishth, Shravan}, title = {Focus, word order and intonation in Hindi}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-46118}, year = {2008}, abstract = {A production study is presented that investigates the effects of word order and information structural context on the prosodic realization of declarative sentences in Hindi. Previous work on Hindi intonation has shown that: (i) non-final content words bear rising pitch accents (Moore 1965, Dyrud 2001, Nair 1999); (ii) focused constituents show greater pitch excursion and longer duration and that post-focal material undergoes pitch range reduction (Moore 1965, Harnsberger 1994, Harnsberger and Judge 1996); and (iii) focused constituents may be followed by a phrase break (Moore 1965). By means of a controlled experiment, we investigated the effect of focus in relation to word order variation using 1200 utterances produced by 20 speakers. Fundamental frequency (F0) and duration of constituents were measured in Subject-Object-Verb (SOV) and Object-Subject-Verb (OSV) sentences in different information structural conditions (wide focus, subject focus and object focus). The analyses indicate that (i) regardless of word order and focus, the constituents are in a strict downstep relationship; (ii) focus is mainly characterized by post-focal pitch range reduction rather than pitch raising of the element in focus; (iii) given expressions that occur pre-focally appear to undergo no reduction; (iv) pitch excursion and duration of the constituents is higher in OSV compared to SOV sentences. A phonological analysis suggests that focus affects pitch scaling and that word order influences prosodic phrasing of the constituents.}, language = {en} } @misc{FeryKuegler2008, author = {F{\´e}ry, Caroline and K{\"u}gler, Frank}, title = {Pitch accent scaling on given, new and focused constituents in German}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-46091}, year = {2008}, abstract = {The influence of information structure on tonal scaling in German is examined experimentally. Eighteen speakers uttered a total of 2277 sentences of the same syntactic structure, but with a varying number of constituents, word order and focus-given structure. The quantified results for German support findings for other Germanic languages that the scaling of high tones, and thus the entire melodic pattern, is influenced by information structure. Narrow focus raised the high tones of pitch accents, while givenness lowered them in prenuclear position and canceled them out postnuclearly. The effects of focus and givenness are calculated against all-new sentences as a baseline, which we expected to be characterized by downstep, a significantly lower scaling of high tones as compared to declination. The results further show that information structure alone cannot account for all variations. We therefore assume that dissimilatory tonal effects play a crucial role in the tonal scaling of German. The effects consist of final f0 drop, a steep fall from a raised high tone to the bottom line of the speaker, H-raising before a low tone, and H-lowering before a raised high tone. No correlation between word order and tone scaling could be established. 2008 Elsevier Ltd. All rights reserved.}, language = {en} } @misc{WulfHeinken2008, author = {Wulf, Monika and Heinken, Thilo}, title = {Colonization of recent coniferous versus deciduous forest stands by vascular plants at the local scale}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-46080}, year = {2008}, abstract = {Questions: 1. Are there differences among species in their preference for coniferous vs. deciduous forest? 2. Are tree and shrub species better colonizers of recent forest stands than herbaceous species? 3. Do colonization patterns of plant species groups depend on tree species composition? Location: Three deciduous and one coniferous recent forest areas in Brandenburg, NE Germany. Methods: In 34 and 21 transects in coniferous and deciduous stands, respectively, we studied the occurrence and percentage cover of vascular plants in a total of 150 plots in ancient stands, 315 in recent stands and 55 at the ecotone. Habitat preference, diaspore weight, generative dispersal potential and clonal extension were used to explain mechanisms of local migration. Regression analysis was conducted to test whether migration distance was related to species' life-history traits. Results: 25 species were significantly associated with ancient stands and ten species were significantly more frequent in recent stands. Tree and shrub species were good colonizers of recent coniferous and deciduous stands. In the coniferous stands, all herbaceous species showed a strong dispersal limitation during colonization, whereas in the deciduous stands generalist species may have survived in the grasslands which were present prior to afforestation. Conclusions: The fast colonization of recent stands by trees and shrubs can be explained by their effective dispersal via wind and animals. This, and the comparably efficient migration of herbaceous forest specialists into recent coniferous stands, implies that the conversion of coniferous into deciduous stands adjacent to ancient deciduous forests is promising even without planting of trees.}, language = {en} } @misc{TsukamotoHeabelValencaetal.2008, author = {Tsukamoto, Junko and Heabel, Sophie and Valenca, Gustavo P. and Peter, Martin and Franco, Telma}, title = {Enzymatic direct synthesis of acrylic acid esters of mono- and disaccharides}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-42652}, year = {2008}, abstract = {BACKGROUND: There is an increased need to replace materials derived from fossil sources by renewables. Sugar-cane derived carbohydrates are very abundant in Brazil and are the cheapest sugars available in the market, with more than 400 million tons of sugarcane processed in the year 2007. The objective of this work was to study the preparation of sugar acrylates from free sugars and free acrylic acid, thus avoiding the previous preparation of protected sugar derivatives, such as glycosides, or activated acrylates, such as vinyl acrylate. RESULTS: Lipase catalyzed esterification of three mono- and two disaccharides with acrylic acid, in the presence or absence of molecular sieves was investigated. The reactions were monitored by high-performance liquid chromatography (HPLC) and the products were analyzed by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry. The main products are mono- and diacrylates, while higher esters are formed as minor products. The highest conversion to sugar acrylates was observed for the D-glucose and D-fructose, followed by D-xylose and D-maltose. Molecular sieves had no pronounced effect on the conversion CONCLUSIONS: A feasible method is described to produce and to characterize sugar acrylates, including those containing more than two acrylate groups. The process for production of these higher esters could potentially be optimized further to produce molecules for cross-linking in acrylate polymerization and other applications. The direct enzymatic esterification of free carbohydrates with acrylic acid is unprecedented.}, language = {en} } @misc{OliveiraJrGueddariMoerschbacheretal.2008, author = {Oliveira Jr, E. N. and Gueddari, Nour E. El and Moerschbacher, Bruno M. and Peter, Martin and Franco, Telma}, title = {Growth of phytopathogenic fungi in the presence of partially acetylated chitooligosaccharides}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-42646}, year = {2008}, abstract = {Four phytopathogenic fungi were cultivated up to six days in media containing chitooligosaccharide mixtures differing in average DP and FA. The three different mixtures were named Q3 (which contained oligosaccharides ofDP2-DP10, withDP2-DP7 asmain components), Q2 (which contained oligosaccharides of DP2-DP12, with DP2-DP10 as main components) and Q1 (which derived from Q2 and contained oligomers of DP5-DP8 with hexamer and a heptamer as the main components). The novel aspect of this work is the description of the effect of mixtures of oligosaccharides with different and known composition on fungal growth rates. The growth rate of Alternaria alternata and Rhizopus stolonifer was initially inhibited by Q3 and Q2 at higher concentrations. Q1 had a growth stimulating effect on these two fungi. Growth of Botrytis cinerea was inhibited by Q3 and Q2, while Q1 had no effect on the growth of this fungus. Growth of Penicillium expansum was only slightly inhibited by higher concentrations of sample Q3, while Q2 and Q1 had no effect. The inhibition of growth rates or their resistance toward chitooligosaccharides correlated with the absence or presence of chitinolytic enzymes in the culture media, respectively.}, language = {en} } @misc{BringmannMutanyattaComarMaksimenkaetal.2008, author = {Bringmann, Gerhard and Mutanyatta-Comar, Joan and Maksimenka, Katja and Wanjohi, John M. and Heydenreich, Matthias and Brun, Reto and M{\"u}ller, Werner E. G. and Peter, Martin and Midiwo, Jacob O. and Yenesew, Abiy}, title = {Joziknipholones A and B : the First Dimeric Phenylanthraquinones, from the Roots of Bulbine frutescens}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-42638}, year = {2008}, abstract = {From the roots of the African plant Bulbine frutescens (Asphodelaceae), two unprecedented novel dimeric phenylanthraquinones, named joziknipholones A and B, possessing axial and centrochirality, were isolated, together with six known compounds. Structural elucidation of the new metabolites was achieved by spectroscopic and chiroptical methods, by reductive cleavage of the central bond between the monomeric phenylanthraquinone and -anthrone portions with sodium dithionite, and by quantum chemical CD calculations. Based on the recently revised absolute axial configuration of the parent phenylanthraquinones, knipholone and knipholone anthrone, the new dimers were attributed to possess the P-configuration (i.e., with the acetyl portions below the anthraquinone plane) at both axes in the case of joziknipholone A, whereas in joziknipholone B, the knipholone part was found to be M-configured. Joziknipholones A and B are active against the chloroquine resistant strain K1 of the malaria pathogen, Plasmodium falciparum, and show moderate activity against murine leukemic lymphoma L5178y cells.}, language = {en} } @misc{SchaeferBungNest2008, author = {Sch{\"a}fer-Bung, Boris and Nest, Mathias}, title = {Correlated dynamics of electrons with reduced two-electron density matrices}, issn = {1866-8372}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-41774}, year = {2008}, abstract = {We present an approach to the correlated dynamics of many-electron systems. We show, that the twoelectron reduced density matrix (2RDM) can provide a suitable description of the real time evolution of a system. To achieve this, the hierarchy of equations of motion must be truncated in a practical way. Also, the computational effort, given that the 2RDM is represented by products of two-electron determinants, is discussed, and numerical model calculations are presented.}, language = {en} } @misc{Koechy2008, author = {K{\"o}chy, Martin}, title = {Effects of simulated daily precipitation patterns on annual plant populations depend on life stage and climatic region}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-33747}, year = {2008}, abstract = {Background: To improve the understanding of consequences of climate change for annual plant communities, I used a detailed, grid-based model that simulates the effect of daily rainfall variability on individual plants in five climatic regions on a gradient from 100 to 800 mm mean annual precipitation (MAP). The model explicitly considers moisture storage in the soil. I manipulated daily rainfall variability by changing the daily mean rain (DMR, rain volume on rainy days averaged across years for each day of the year) by ± 20\%. At the same time I adjusted intervals appropriately between rainy days for keeping the mean annual volume constant. In factorial combination with changing DMR I also changed MAP by ± 20\%. Results: Increasing MAP generally increased water availability, establishment, and peak shoot biomass. Increasing DMR increased the time that water was continuously available to plants in the upper 15 to 30 cm of the soil (longest wet period, LWP). The effect of DMR diminished with increasing humidity of the climate. An interaction between water availability and density-dependent germination increased the establishment of seedlings in the arid region, but in the more humid regions the establishment of seedlings decreased with increasing DMR. As plants matured, competition among individuals and their productivity increased, but the size of these effects decreased with the humidity of the regions. Therefore, peak shoot biomass generally increased with increasing DMR but the effect size diminished from the semiarid to the mesic Mediterranean region. Increasing DMR reduced via LWP the annual variability of biomass in the semiarid and dry Mediterranean regions. Conclusion: More rainstorms (greater DMR) increased the recharge of soil water reservoirs in more arid sites with consequences for germination, establishment, productivity, and population persistence. The order of magnitudes of DMR and MAP overlapped partially so that their combined effect is important for projections of climate change effects on annual vegetation.}, language = {en} } @misc{Kuhl2008, author = {Kuhl, Mara}, title = {Gender mainstreaming in Estonia}, issn = {1867-5808}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-33357}, year = {2008}, abstract = {Content: 1 The Development of the Estonian Gender Policy Machinery 1.1 Initiation of Institutionalisation as a Result of International Commitments 1.2 Institutional Measures Facilitating EU Membership 1.3 Assessment of the Gender Equality Machinery 2 Conditions for Gender Mainstreaming in Estonia 2.1 Social Conditions 2.2 Administrative Conditions 3 Gender Mainstreaming Activities in the Estonian Public Administration 3.1 The Legal Foundations 3.2 Inter-ministerial Cooperation 3.3 Gender Mainstreaming Training 3.4 Knowledge Basis 3.5 Lack of Standards for data and Statistics 3.6 Non-adminsitrative Liaisons 4 Conclusion}, language = {en} } @misc{KoechyMathajJeltschetal.2008, author = {K{\"o}chy, Martin and Mathaj, Martin and Jeltsch, Florian and Malkinson, Dan}, title = {Resilience of stocking capacity to changing climate in arid to Mediterranean landscapes}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-18720}, year = {2008}, abstract = {Small livestock is an important resource for rural human populations in dry climates. How strongly will climate change affect the capacity of the rangeland? We used hierarchical modelling to scale quantitatively the growth of shrubs and annual plants, the main food of sheep and goats, to the landscape extent in the eastern Mediterranean region. Without grazing, productivity increased in a sigmoid way with mean annual precipitation. Grazing reduced productivity more strongly the drier the landscape. At a point just under the stocking capacity of the vegetation, productivity declined precipitously with more intense grazing due to a lack of seed production of annuals. We repeated simulations with precipitation patterns projected by two contrasting IPCC scenarios. Compared to results based on historic patterns, productivity and stocking capacity did not differ in most cases. Thus, grazing intensity remains the stronger impact on landscape productivity in this dry region even in the future.}, language = {en} } @misc{ChampagnatRoelly2008, author = {Champagnat, Nicolas and Roelly, Sylvie}, title = {Limit theorems for conditioned multitype Dawson-Watanabe processes and Feller diffusions}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-18610}, year = {2008}, abstract = {A multitype Dawson-Watanabe process is conditioned, in subcritical and critical cases, on non-extinction in the remote future. On every finite time interval, its distribution is absolutely continuous with respect to the law of the unconditioned process. A martingale problem characterization is also given. Several results on the long time behavior of the conditioned mass process - the conditioned multitype Feller branching diffusion - are then proved. The general case is first considered, where the mutation matrix which models the interaction between the types, is irreducible. Several two-type models with decomposable mutation matrices are analyzed too .}, language = {en} } @misc{KoechyBrakenhielm2008, author = {K{\"o}chy, Martin and Br{\aa}kenhielm, Sven}, title = {Separation of effects of moderate N deposition from natural change in ground vegetation of forests and bogs}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-16621}, year = {2008}, abstract = {The effect of moderate rates of nitrogen deposition on ground floor vegetation is poorly predicted by uncontrolled surveys or fertilization experiments using high rates of nitrogen (N) addition. We compared the temporal trends of ground floor vegetation in permanent plots with moderate (7-13 kg ha-1 year-1) and lower bulk N deposition (4-6 kg ha-1 year-1) in southern Sweden during 1982-1998. We examined whether trends differed between growth forms (vascular plants and bryophytes) and vegetation types (three types of coniferous forest, deciduous forest, and bog). Trends of site-standardized cover and richness varied among growth forms, vegetation types, and deposition regions. Cover in spruce forests decreased at the same rate with both moderate and low deposition. In pine forests cover decreased faster with moderate deposition and in bogs cover decreased faster with low deposition. Cover of bryophytes in spruce forests increased at the same rate with both moderate and low deposition. In pine forests cover decreased faster with moderate deposition and in bogs and deciduous forests there was a strong non-linear increase with moderate deposition. The trend of number of vascular plants was constant with moderate and decreased with low deposition. We found no trend in the number of bryophyte species. We propose that the decrease of cover and number with low deposition was related to normal ecosystem development (increased shading), suggesting that N deposition maintained or increased the competitiveness of some species in the moderate-deposition region. Deposition had no consistent negative effect on vegetation suggesting that it is less important than normal successional processes.}, language = {en} }