@unpublished{FlandoliHoegele2014, author = {Flandoli, Franco and H{\"o}gele, Michael}, title = {A solution selection problem with small stable perturbations}, volume = {3}, number = {8}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, issn = {2193-6943}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-71205}, pages = {43}, year = {2014}, abstract = {The zero-noise limit of differential equations with singular coefficients is investigated for the first time in the case when the noise is a general alpha-stable process. It is proved that extremal solutions are selected and the probability of selection is computed. Detailed analysis of the characteristic function of an exit time form on the half-line is performed, with a suitable decomposition in small and large jumps adapted to the singular drift.}, language = {en} } @article{SpahnVieiraNetoGuimaraesetal.2014, author = {Spahn, Frank and Vieira Neto, E. and Guimaraes, A. H. F. and Gorban, A. N. and Brilliantov, Nikolai V.}, title = {A statistical model of aggregate fragmentation}, series = {New journal of physics : the open-access journal for physics}, volume = {16}, journal = {New journal of physics : the open-access journal for physics}, publisher = {IOP Publ. Ltd.}, address = {Bristol}, issn = {1367-2630}, doi = {10.1088/1367-2630/16/1/013031}, pages = {11}, year = {2014}, abstract = {A statistical model of fragmentation of aggregates is proposed, based on the stochastic propagation of cracks through the body. The propagation rules are formulated on a lattice and mimic two important features of the process-a crack moves against the stress gradient while dissipating energy during its growth. We perform numerical simulations of the model for two-dimensional lattice and reveal that the mass distribution for small-and intermediate-size fragments obeys a power law, F(m) proportional to m(-3/2), in agreement with experimental observations. We develop an analytical theory which explains the detected power law and demonstrate that the overall fragment mass distribution in our model agrees qualitatively with that one observed in experiments.}, language = {en} } @article{OmidbakhshfardWinckArvidssonetal.2014, author = {Omidbakhshfard, Mohammad Amin and Winck, Flavia Vischi and Arvidsson, Samuel Janne and Riano-Pachon, Diego M. and M{\"u}ller-R{\"o}ber, Bernd}, title = {A step-by-step protocol for formaldehyde-assisted isolation of regulatory elements from Arabidopsis thaliana}, series = {Journal of integrative plant biology}, volume = {56}, journal = {Journal of integrative plant biology}, number = {6}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {1672-9072}, doi = {10.1111/jipb.12151}, pages = {527 -- 538}, year = {2014}, abstract = {The control of gene expression by transcriptional regulators and other types of functionally relevant DNA transactions such as chromatin remodeling and replication underlie a vast spectrum of biological processes in all organisms. DNA transactions require the controlled interaction of proteins with DNA sequence motifs which are often located in nucleosome-depleted regions (NDRs) of the chromatin. Formaldehyde-assisted isolation of regulatory elements (FAIRE) has been established as an easy-to-implement method for the isolation of NDRs from a number of eukaryotic organisms, and it has been successfully employed for the discovery of new regulatory segments in genomic DNA from, for example, yeast, Drosophila, and humans. Until today, however, FAIRE has only rarely been employed in plant research and currently no detailed FAIRE protocol for plants has been published. Here, we provide a step-by-step FAIRE protocol for NDR discovery in Arabidopsis thaliana. We demonstrate that NDRs isolated from plant chromatin are readily amenable to quantitative polymerase chain reaction and next-generation sequencing. Only minor modification of the FAIRE protocol will be needed to adapt it to other plants, thus facilitating the global inventory of regulatory regions across species.}, language = {en} } @phdthesis{Herenz2014, author = {Herenz, Peter}, title = {A study of the absorption characteristics of gaseous galaxy halos in the local Universe}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-70513}, school = {Universit{\"a}t Potsdam}, year = {2014}, abstract = {Today, it is well known that galaxies like the Milky Way consist not only of stars but also of gas and dust. The galactic halo, a sphere of gas that surrounds the stellar disk of a galaxy, is especially interesting. It provides a wealth of information about in and outflowing gaseous material towards and away from galaxies and their hierarchical evolution. For the Milky Way, the so-called high-velocity clouds (HVCs), fast moving neutral gas complexes in the halo that can be traced by absorption-line measurements, are believed to play a crucial role in the overall matter cycle in our Galaxy. Over the last decades, the properties of these halo structures and their connection to the local circumgalactic and intergalactic medium (CGM and IGM, respectively) have been investigated in great detail by many different groups. So far it remains unclear, however, to what extent the results of these studies can be transferred to other galaxies in the local Universe. In this thesis, we study the absorption properties of Galactic HVCs and compare the HVC absorption characteristics with those of intervening QSO absorption-line systems at low redshift. The goal of this project is to improve our understanding of the spatial extent and physical conditions of gaseous galaxy halos in the local Universe. In the first part of the thesis we use HST /STIS ultraviolet spectra of more than 40 extragalactic background sources to statistically analyze the absorption properties of the HVCs in the Galactic halo. We determine fundamental absorption line parameters including covering fractions of different weakly/intermediately/highly ionized metals with a particular focus on SiII and MgII. Due to the similarity in the ionization properties of SiII and MgII, we are able to estimate the contribution of HVC-like halo structures to the cross section of intervening strong MgII absorbers at z = 0. Our study implies that only the most massive HVCs would be regarded as strong MgII absorbers, if the Milky Way halo would be seen as a QSO absorption line system from an exterior vantage point. Combining the observed absorption-cross section of Galactic HVCs with the well-known number density of intervening strong MgII absorbers at z = 0, we conclude that the contribution of infalling gas clouds (i.e., HVC analogs) in the halos of Milky Way-type galaxies to the cross section of strong MgII absorbers is 34\%. This result indicates that only about one third of the strong MgII absorption can be associated with HVC analogs around other galaxies, while the majority of the strong MgII systems possibly is related to galaxy outflows and winds. The second part of this thesis focuses on the properties of intervening metal absorbers at low redshift. The analysis of the frequency and physical conditions of intervening metal systems in QSO spectra and their relation to nearby galaxies offers new insights into the typical conditions of gaseous galaxy halos. One major aspect in our study was to regard intervening metal systems as possible HVC analogs. We perform a detailed analysis of absorption line properties and line statistics for 57 metal absorbers along 78 QSO sightlines using newly-obtained ultraviolet spectra obtained with HST /COS. We find clear evidence for bimodal distribution in the HI column density in the absorbers, a trend that we interpret as sign for two different classes of absorption systems (with HVC analogs at the high-column density end). With the help of the strong transitions of SiII λ1260, SiIII λ1206, and CIII λ977 we have set up Cloudy photoionization models to estimate the local ionization conditions, gas densities, and metallicities. We find that the intervening absorption systems studied by us have, on average, similar physical conditions as Galactic HVC absorbers, providing evidence that many of them represent HVC analogs in the vicinity of other galaxies. We therefore determine typical halo sizes for SiII, SiIII, and CIII for L = 0.01L∗ and L = 0.05L∗ galaxies. Based on the covering fractions of the different ions in the Galactic halo, we find that, for example, the typical halo size for SiIII is ∼ 160 kpc for L = 0.05L∗ galaxies. We test the plausibility of this result by searching for known galaxies close to the QSO sightlines and at similar redshifts as the absorbers. We find that more than 34\% of the measured SiIII absorbers have galaxies associated with them, with the majority of the absorbers indeed being at impact parameters ρ ≤160 kpc.}, language = {en} } @article{MolkenthinScherbaumGriewanketal.2014, author = {Molkenthin, Christian and Scherbaum, Frank and Griewank, Andreas and Kuehn, Nicolas and Stafford, Peter}, title = {A Study of the sensitivity of response spectral amplitudes on seismological parameters using algorithmic differentiation}, series = {Bulletin of the Seismological Society of America}, volume = {104}, journal = {Bulletin of the Seismological Society of America}, number = {5}, publisher = {Seismological Society of America}, address = {Albany}, issn = {0037-1106}, doi = {10.1785/0120140022}, pages = {2240 -- 2252}, year = {2014}, abstract = {Response spectra are of fundamental importance in earthquake engineering and represent a standard measure in seismic design for the assessment of structural performance. However, unlike Fourier spectral amplitudes, the relationship of response spectral amplitudes to seismological source, path, and site characteristics is not immediately obvious and might even be considered counterintuitive for high oscillator frequencies. The understanding of this relationship is nevertheless important for seismic-hazard analysis. The purpose of the present study is to comprehensively characterize the variation of response spectral amplitudes due to perturbations of the causative seismological parameters. This is done by calculating the absolute parameter sensitivities (sensitivity coefficients) defined as the partial derivatives of the model output with respect to its input parameters. To derive sensitivities, we apply algorithmic differentiation (AD). This powerful approach is extensively used for sensitivity analysis of complex models in meteorology or aerodynamics. To the best of our knowledge, AD has not been explored yet in the seismic-hazard context. Within the present study, AD was successfully implemented for a proven and extensively applied simulation program for response spectra (Stochastic Method SIMulation [SMSIM]) using the TAPENADE AD tool. We assess the effects and importance of input parameter perturbations on the shape of response spectra for different regional stochastic models in a quantitative way. Additionally, we perform sensitivity analysis regarding adjustment issues of groundmotion prediction equations.}, language = {en} } @article{MondalBhuniaKellingetal.2014, author = {Mondal, Suvendu Sekhar and Bhunia, Asamanjoy and Kelling, Alexandra and Schilde, Uwe and Janiak, Christoph and Holdt, Hans-J{\"u}rgen}, title = {A supramolecular Co(II)(14)- metal-organic cube in a hydrogen-bonded network and a Co(II)-organic framework with a flexible methoxy substituent}, series = {Chemical communications}, volume = {50}, journal = {Chemical communications}, number = {41}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1359-7345}, doi = {10.1039/c3cc49698h}, pages = {5441 -- 5443}, year = {2014}, abstract = {The reaction of 4,5-dicyano-2-methoxyimidazole (L1) with Co(NO3)(2.) 6H(2)O under solvothermal conditions in DMF, a MOF, IFP-8 and a hydrogen-bonded network consisting of tetradecanuclear Co(II)(14)-metal organic cube (1) are achieved. 1 shows the bcu net with 14 cobalt atoms.}, language = {en} } @misc{MondalBhuniaKellingetal.2014, author = {Mondal, Suvendu Sekhar and Bhunia, Asamanjoy and Kelling, Alexandra and Schilde, Uwe and Janiak, Christoph and Holdt, Hans-J{\"u}rgen}, title = {A supramolecular Co(II)₁₄-metal-organic cube in a hydrogen-bonded network and a Co(II)-organic framework with a flexible methoxy substituent}, number = {169}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-74098}, pages = {5441 -- 5443}, year = {2014}, abstract = {The reaction of 4,5-dicyano-2-methoxyimidazole (L1) with Co(NO3)2·6H2O under solvothermal conditions in DMF, a MOF, IFP-8 and a hydrogen-bonded network consisting of tetradecanuclear Co(II)14-metal organic cube (1) are achieved. 1 shows the bcu net with 14 cobalt atoms.}, language = {en} } @article{MondalBhuniaKellingetal.2014, author = {Mondal, Suvendu Sekhar and Bhunia, Asamanjoy and Kelling, Alexandra and Schilde, Uwe and Janiak, Christoph and Holdt, Hans-J{\"u}rgen}, title = {A supramolecular Co(II)₁₄-metal-organic cube in a hydrogen-bonded network and a Co(II)-organic framework with a flexible methoxy substituent}, series = {Chemical communications : ChemComm}, volume = {2014}, journal = {Chemical communications : ChemComm}, number = {41}, publisher = {Royal Society of Chemistry}, issn = {2046-2069}, doi = {10.1039/c3cc49698h}, pages = {5441 -- 5443}, year = {2014}, abstract = {The reaction of 4,5-dicyano-2-methoxyimidazole (L1) with Co(NO3)2·6H2O under solvothermal conditions in DMF, a MOF, IFP-8 and a hydrogen-bonded network consisting of tetradecanuclear Co(II)14-metal organic cube (1) are achieved. 1 shows the bcu net with 14 cobalt atoms.}, language = {en} } @article{BuchwaldWagelaarDanetal.2014, author = {Buchwald, Sebastian and Wagelaar, Dennis and Dan, Li and Hegedues, Abel and Herrmannsdoerfer, Markus and Horn, Tassilo and Kalnina, Elina and Krause, Christian and Lano, Kevin and Lepper, Markus and Rensink, Arend and Rose, Louis and Waetzoldt, Sebastian and Mazanek, Steffen}, title = {A survey and comparison of transformation tools based on the transformation tool contest}, series = {Science of computer programming}, volume = {85}, journal = {Science of computer programming}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0167-6423}, doi = {10.1016/j.scico.2013.10.009}, pages = {41 -- 99}, year = {2014}, abstract = {Model transformation is one of the key tasks in model-driven engineering and relies on the efficient matching and modification of graph-based data structures; its sibling graph rewriting has been used to successfully model problems in a variety of domains. Over the last years, a wide range of graph and model transformation tools have been developed all of them with their own particular strengths and typical application domains. In this paper, we give a survey and a comparison of the model and graph transformation tools that participated at the Transformation Tool Contest 2011. The reader gains an overview of the field and its tools, based on the illustrative solutions submitted to a Hello World task, and a comparison alongside a detailed taxonomy. The article is of interest to researchers in the field of model and graph transformation, as well as to software engineers with a transformation task at hand who have to choose a tool fitting to their needs. All solutions referenced in this article provide a SHARE demo. It supported the peer-review process for the contest, and now allows the reader to test the tools online.}, language = {en} } @article{LuckeRensing2014, author = {Lucke, Ulrike and Rensing, Christoph}, title = {A survey on pervasive education}, series = {Pervasive and mobile computing}, volume = {14}, journal = {Pervasive and mobile computing}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1574-1192}, doi = {10.1016/j.pmcj.2013.12.001}, pages = {3 -- 16}, year = {2014}, abstract = {Researchers and developers worldwide have put their efforts into the design, development and use of information and communication technology to support teaching and learning. This research is driven by pedagogical as well as technological disciplines. The most challenging ideas are currently found in the application of mobile, ubiquitous, pervasive, contextualized and seamless technologies for education, which we shall refer to as pervasive education. This article provides a comprehensive overview of the existing work in this field and categorizes it with respect to educational settings. Using this approach, best practice solutions for certain educational settings and open questions for pervasive education are highlighted in order to inspire interested developers and educators. The work is assigned to different fields, identified by the main pervasive technologies used and the educational settings. Based on these assignments we identify areas within pervasive education that are currently disregarded or deemed challenging so that further research and development in these fields are stimulated in a trans-disciplinary approach. (C) 2013 Elsevier B.V. All rights reserved.}, language = {en} }