@misc{WeisseMiddletonHuisinga2010, author = {Weiße, Andrea Y. and Middleton, Richard H. and Huisinga, Wilhelm}, title = {Quantifying uncertainty, variability and likelihood for ordinary differential equation models}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {894}, issn = {1866-8372}, doi = {10.25932/publishup-43134}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-431340}, pages = {12}, year = {2010}, abstract = {Background In many applications, ordinary differential equation (ODE) models are subject to uncertainty or variability in initial conditions and parameters. Both, uncertainty and variability can be quantified in terms of a probability density function on the state and parameter space. Results The partial differential equation that describes the evolution of this probability density function has a form that is particularly amenable to application of the well-known method of characteristics. The value of the density at some point in time is directly accessible by the solution of the original ODE extended by a single extra dimension (for the value of the density). This leads to simple methods for studying uncertainty, variability and likelihood, with significant advantages over more traditional Monte Carlo and related approaches especially when studying regions with low probability. Conclusions While such approaches based on the method of characteristics are common practice in other disciplines, their advantages for the study of biological systems have so far remained unrecognized. Several examples illustrate performance and accuracy of the approach and its limitations.}, language = {en} } @misc{ShirzadianKhorramabadJingEvertsetal.2010, author = {Shirzadian-Khorramabad, Reza and Jing, Hai-Chun and Everts, Gerja E. and Schippers, Jos H. M. and Hille, Jacques and Dijkwel, Paul P.}, title = {A mutation in the cytosolic O-acetylserine (thiol) lyase induces a genome-dependent early leaf death phenotype in Arabidopsis}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, number = {833}, issn = {1866-8372}, doi = {10.25932/publishup-42757}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-427574}, pages = {14}, year = {2010}, abstract = {Background: Cysteine is a component in organic compounds including glutathione that have been implicated in the adaptation of plants to stresses. O-acetylserine (thiol) lyase (OAS-TL) catalyses the final step of cysteine biosynthesis. OAS-TL enzyme isoforms are localised in the cytoplasm, the plastids and mitochondria but the contribution of individual OAS-TL isoforms to plant sulphur metabolism has not yet been fully clarified. Results: The seedling lethal phenotype of the Arabidopsis onset of leaf death3-1 (old3-1) mutant is due to a point mutation in the OAS-A1 gene, encoding the cytosolic OAS-TL. The mutation causes a single amino acid substitution from Gly(162) to Glu(162), abolishing old3-1 OAS-TL activity in vitro. The old3-1 mutation segregates as a monogenic semidominant trait when backcrossed to its wild type accession Landsberg erecta (Ler-0) and the Di-2 accession. Consistent with its semi-dominant behaviour, wild type Ler-0 plants transformed with the mutated old3-1 gene, displayed the early leaf death phenotype. However, the old3-1 mutation segregates in an 11: 4: 1 (wild type: semi-dominant: mutant) ratio when backcrossed to the Colombia-0 and Wassilewskija accessions. Thus, the early leaf death phenotype depends on two semi-dominant loci. The second locus that determines the old3-1 early leaf death phenotype is referred to as odd-ler (for old3 determinant in the Ler accession) and is located on chromosome 3. The early leaf death phenotype is temperature dependent and is associated with increased expression of defence-response and oxidative-stress marker genes. Independent of the presence of the odd-ler gene, OAS-A1 is involved in maintaining sulphur and thiol levels and is required for resistance against cadmium stress. Conclusions: The cytosolic OAS-TL is involved in maintaining organic sulphur levels. The old3-1 mutation causes genome-dependent and independent phenotypes and uncovers a novel function for the mutated OAS-TL in cell death regulation.}, language = {en} } @misc{Budke2010, author = {Budke, Alexandra}, title = {Und der Zukunft abgewandt}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, number = {813}, isbn = {978-3-89971-627-6}, issn = {1866-8372}, doi = {10.25932/publishup-41080}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-410801}, pages = {411}, year = {2010}, abstract = {Seit dem Ende der DDR, das den Zusammenbruch des Ostblocks und damit die Beendigung des »Kalten Kriegs« einleitete, wird verst{\"a}rkt versucht, das Wesen dieses Staates zu definieren und damit seine Folgen auf wirtschaftlicher, sozialer, psychologischer und bildungspolitischer Ebene zu verstehen und einzuordnen. Alexandra Budke analysiert in diesem Band das Schulfach Geographie, das neben der Staatsb{\"u}rgerkunde und der Geschichte ein zentrales Fach war und in dem die in den Lehrpl{\"a}nen definierte »staatsb{\"u}rgerliche, weltanschauliche oder ideologische Erziehung« auf der Grundlage des Marxismus-Leninismus stattfinden sollte. Sie kl{\"a}rt, inwiefern Geographieunterricht in der DDR genutzt wurde, um geopolitische Interessen des Staates zu kommunizieren und zu verbreiten. Damit l{\"a}sst sich durch die detaillierte Analyse des Fachunterrichts auch die Frage beantworten, ob Sch{\"u}lerInnen im Unterricht politisch manipuliert wurden und welche Handlungsm{\"o}glichkeiten die zentralen Akteure des Unterrichts, die LehrerInnen und die Sch{\"u}lerInnen, im Rahmen der durch die Bildungspolitik gesetzten curricularen Vorgaben wahrgenommen haben.}, language = {de} } @misc{WestendorfBaeErlenkamperetal.2010, author = {Westendorf, Christian and Bae, Albert J. and Erlenkamper, Christoph and Galland, Edouard and Franck, Carl and Bodenschatz, Eberhard and Beta, Carsten}, title = {Live cell flattening}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, number = {835}, issn = {1866-8372}, doi = {10.25932/publishup-42831}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-428311}, pages = {17}, year = {2010}, abstract = {Eukaryotic cell flattening is valuable for improving microscopic observations, ranging from bright field (BF) to total internal reflection fluorescence (TIRF) microscopy. Fundamental processes, such as mitosis and in vivo actin polymerization, have been investigated using these techniques. Here, we review the well known agar overlayer protocol and the oil overlay method. In addition, we present more elaborate microfluidics-based techniques that provide us with a greater level of control. We demonstrate these techniques on the social amoebae Dictyostelium discoideum, comparing the advantages and disadvantages of each method.}, language = {en} } @misc{RepsilberKernTelaaretal.2010, author = {Repsilber, Dirk and Kern, Sabine and Telaar, Anna and Walzl, Gerhard and Black, Gillian F. and Selbig, Joachim and Parida, Shreemanta K. and Kaufmann, Stefan H. E. and Jacobsen, Marc}, title = {Biomarker discovery in heterogeneous tissue samples}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {854}, issn = {1866-8372}, doi = {10.25932/publishup-42934}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-429343}, pages = {17}, year = {2010}, abstract = {Background: For heterogeneous tissues, such as blood, measurements of gene expression are confounded by relative proportions of cell types involved. Conclusions have to rely on estimation of gene expression signals for homogeneous cell populations, e.g. by applying micro-dissection, fluorescence activated cell sorting, or in-silico deconfounding. We studied feasibility and validity of a non-negative matrix decomposition algorithm using experimental gene expression data for blood and sorted cells from the same donor samples. Our objective was to optimize the algorithm regarding detection of differentially expressed genes and to enable its use for classification in the difficult scenario of reversely regulated genes. This would be of importance for the identification of candidate biomarkers in heterogeneous tissues. Results: Experimental data and simulation studies involving noise parameters estimated from these data revealed that for valid detection of differential gene expression, quantile normalization and use of non-log data are optimal. We demonstrate the feasibility of predicting proportions of constituting cell types from gene expression data of single samples, as a prerequisite for a deconfounding-based classification approach. Classification cross-validation errors with and without using deconfounding results are reported as well as sample-size dependencies. Implementation of the algorithm, simulation and analysis scripts are available. Conclusions: The deconfounding algorithm without decorrelation using quantile normalization on non-log data is proposed for biomarkers that are difficult to detect, and for cases where confounding by varying proportions of cell types is the suspected reason. In this case, a deconfounding ranking approach can be used as a powerful alternative to, or complement of, other statistical learning approaches to define candidate biomarkers for molecular diagnosis and prediction in biomedicine, in realistically noisy conditions and with moderate sample sizes.}, language = {en} } @misc{Beta2010, author = {Beta, Carsten}, title = {Bistability in the actin cortex}, series = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe}, volume = {3}, journal = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe}, number = {12}, doi = {10.25932/publishup-42938}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-429385}, pages = {9}, year = {2010}, abstract = {Multi-color fluorescence imaging experiments of wave forming Dictyostelium cells have revealed that actin waves separate two domains of the cell cortex that differ in their actin structure and phosphoinositide composition. We propose a bistable model of actin dynamics to account for these experimental observation. The model is based on the simplifying assumption that the actin cytoskeleton is composed of two distinct network types, a dendritic and a bundled network. The two structurally different states that were observed in experiments correspond to the stable fixed points in the bistable regime of this model. Each fixed point is dominated by one of the two network types. The experimentally observed actin waves can be considered as trigger waves that propagate transitions between the two stable fixed points.}, language = {en} } @misc{HajialioghliMoazzenJahangirietal.2010, author = {Hajialioghli, Robab and Moazzen, Mohssen and Jahangiri, Ahmad and Oberh{\"a}nsli, Roland and Mocek, Beate and Altenberger, Uwe}, title = {Petrogenesis and tectonic evolution of metaluminous sub-alkaline granitoids from the Takab Complex, NW Iran}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {570}, issn = {1866-8372}, doi = {10.25932/publishup-41310}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-413100}, pages = {19}, year = {2010}, abstract = {The Takab complex is composed of a variety of metamorphic rocks including amphibolites, metapelites, mafic granulites, migmatites and meta-ultramafics, which are intruded by the granitoid. The granitoid magmatic activity occurred in relation to the subduction of the Neo-Tethys oceanic crust beneath the Iranian crust during Tertiary times. The granitoids are mainly granodiorite, quartz monzodiorite, monzonite and quartz diorite. Chemically, the magmatic rocks are characterized by ASI < 1.04, AI < 0.87 and high contents of CaO (up to ∼ 14.5 wt \%), which are consistent with the I-type magmatic series. Low FeO t /(FeO t +MgO) values (< 0.75) as well as low Nb, Y and K 2 O contents of the investigated rocks resemble the calc-alkaline series. Low SiO 2 , K 2 O/Na 2 O and Al 2 O 3 accompanied by high CaO and FeO contents indicate melting of metabasites as an appropriate source for the intrusions. Negative Ti and Nb anomalies verify a metaluminous crustal origin for the protoliths of the investigated igneous rocks. These are comparable with compositions of the associated mafic migmatites, in the Takab metamorphic complex, which originated from the partial melting of amphibolites. Therefore, crustal melting and a collision-related origin for the Takab calc-alkaline intrusions are proposed here on the basis of mineralogy and geochemical characteristics. The P-T evolution during magmatic crystallization and subsolidus cooling stages is determined by the study of mineral chemistry of the granodiorite and the quartz diorite. Magmatic crystallization pressure and temperature for the quartz-diorite and the granodiorite are estimated to be P ∼ 7.8 ± 2.5 kbar, T ∼ 760 ± 75 ◦C and P ∼ 5 ± 1 kbar, T ∼ 700 ◦C, respectively. Subsolidus conditions are consistent with temperatures of ∼ 620 ◦C and ∼ 600 ◦C, and pressures of ∼ 5 kbar and ∼ 3.5 kbar for the quartz-diorite and the granodiorite, respectively.}, language = {en} } @misc{MargariaSteffenKubczak2010, author = {Margaria, Tiziana and Steffen, Bernhard and Kubczak, Christian}, title = {Evolution support in heterogeneous service-oriented landscapes}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {918}, issn = {1866-8372}, doi = {10.25932/publishup-43240}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-432405}, pages = {15}, year = {2010}, abstract = {We present an approach that provides automatic or semi-automatic support for evolution and change management in heterogeneous legacy landscapes where (1) legacy heterogeneous, possibly distributed platforms are integrated in a service oriented fashion, (2) the coordination of functionality is provided at the service level, through orchestration, (3) compliance and correctness are provided through policies and business rules, (4) evolution and correctness-by-design are supported by the eXtreme Model Driven Development paradigm (XMDD) offered by the jABC (Margaria and Steffen in Annu. Rev. Commun. 57, 2004)—the model-driven service oriented development platform we use here for integration, design, evolution, and governance. The artifacts are here semantically enriched, so that automatic synthesis plugins can field the vision of Enterprise Physics: knowledge driven business process development for the end user. We demonstrate this vision along a concrete case study that became over the past three years a benchmark for Semantic Web Service discovery and mediation. We enhance the Mediation Scenario of the Semantic Web Service Challenge along the 2 central evolution paradigms that occur in practice: (a) Platform migration: platform substitution of a legacy system by an ERP system and (b) Backend extension: extension of the legacy Customer Relationship Management (CRM) and Order Management System (OMS) backends via an additional ERP layer.}, language = {en} } @misc{RianoPachonKleessenNeigenfindetal.2010, author = {Ria{\~n}o-Pach{\´o}n, Diego Mauricio and Kleessen, Sabrina and Neigenfind, Jost and Durek, Pawel and Weber, Elke and Engelsberger, Wolfgang R. and Walther, Dirk and Selbig, Joachim and Schulze, Waltraud X. and Kersten, Birgit}, title = {Proteome-wide survey of phosphorylation patterns affected by nuclear DNA polymorphisms in Arabidopsis thaliana}, 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 = {1328}, issn = {1866-8372}, doi = {10.25932/publishup-43118}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-431181}, pages = {19}, year = {2010}, abstract = {Background: Protein phosphorylation is an important post-translational modification influencing many aspects of dynamic cellular behavior. Site-specific phosphorylation of amino acid residues serine, threonine, and tyrosine can have profound effects on protein structure, activity, stability, and interaction with other biomolecules. Phosphorylation sites can be affected in diverse ways in members of any species, one such way is through single nucleotide polymorphisms (SNPs). The availability of large numbers of experimentally identified phosphorylation sites, and of natural variation datasets in Arabidopsis thaliana prompted us to analyze the effect of non-synonymous SNPs (nsSNPs) onto phosphorylation sites. Results: From the analyses of 7,178 experimentally identified phosphorylation sites we found that: (i) Proteins with multiple phosphorylation sites occur more often than expected by chance. (ii) Phosphorylation hotspots show a preference to be located outside conserved domains. (iii) nsSNPs affected experimental phosphorylation sites as much as the corresponding non-phosphorylated amino acid residues. (iv) Losses of experimental phosphorylation sites by nsSNPs were identified in 86 A. thaliana proteins, among them receptor proteins were overrepresented. These results were confirmed by similar analyses of predicted phosphorylation sites in A. thaliana. In addition, predicted threonine phosphorylation sites showed a significant enrichment of nsSNPs towards asparagines and a significant depletion of the synonymous substitution. Proteins in which predicted phosphorylation sites were affected by nsSNPs (loss and gain), were determined to be mainly receptor proteins, stress response proteins and proteins involved in nucleotide and protein binding. Proteins involved in metabolism, catalytic activity and biosynthesis were less affected. Conclusions: We analyzed more than 7,100 experimentally identified phosphorylation sites in almost 4,300 protein-coding loci in silico, thus constituting the largest phosphoproteomics dataset for A. thaliana available to date. Our findings suggest a relatively high variability in the presence or absence of phosphorylation sites between different natural accessions in receptor and other proteins involved in signal transduction. Elucidating the effect of phosphorylation sites affected by nsSNPs on adaptive responses represents an exciting research goal for the future.}, language = {en} } @article{MickelssonPaycha2010, author = {Mickelsson, Jouko and Paycha, Sylvie}, title = {The logarithmic residue density of a generalized Laplacian}, series = {Journal of the Australian Mathematical Society}, volume = {90}, journal = {Journal of the Australian Mathematical Society}, number = {1}, publisher = {Cambridge Univ. Press}, address = {Cambridge}, issn = {0263-6115}, doi = {10.1017/S144678871100108X}, pages = {53 -- 80}, year = {2010}, abstract = {We show that the residue density of the logarithm of a generalized Laplacian on a closed manifold definesan invariant polynomial-valued differential form. We express it in terms of a finite sum of residues ofclassical pseudodifferential symbols. In the case of the square of a Dirac operator, these formulas providea pedestrian proof of the Atiyah-Singer formula for a pure Dirac operator in four dimensions and for atwisted Dirac operator on a flat space of any dimension. These correspond to special cases of a moregeneral formula by Scott and Zagier. In our approach, which is of perturbative nature, we use either aCampbell-Hausdorff formula derived by Okikiolu or a noncommutative Taylor-type formula.}, language = {en} }