Molecular cytogenetic differentiation of paralogs of Hox paralogs in duplicated and re-diploidized genome of the North American paddlefish (Polyodon spathula).

BackgroundAcipenseriformes is a basal lineage of ray-finned fishes and comprise 27 extant species of sturgeons and paddlefishes. They are characterized by several specific genomic features as broad ploidy variation, high chromosome numbers, presence of numerous microchromosomes and propensity to interspecific hybridization. The presumed palaeotetraploidy of the American paddlefish was recently validated by molecular phylogeny and Hox genes analyses. A whole genome duplication in the paddlefish lineage was estimated at approximately 42 Mya and was found to be independent from several genome duplications evidenced in its sister lineage, i.e. sturgeons. We tested the ploidy status of available chromosomal markers after the expected rediploidization. Further we tested, whether paralogs of Hox gene clusters originated from this paddlefish specific genome duplication are cytogenetically distinguishable.ResultsWe found that both paralogs HoxA alpha and beta were distinguishable without any overlapping of the hybridization signal - each on one pair of large metacentric chromosomes. Of the HoxD, only the beta paralog was unequivocally identified, whereas the alpha paralog did not work and yielded only an inconclusive diffuse signal. Chromosomal markers on three diverse ploidy levels reflecting different stages of rediploidization were identified: quadruplets retaining their ancestral tetraploid condition, semi-quadruplets still reflecting the ancestral tetraploidy with clear signs of advanced rediploidization, doublets were diploidized with ancestral tetraploidy already blurred. Also some of the available microsatellite data exhibited diploid allelic band patterns at their loci whereas another locus showed more than two alleles.ConclusionsOur exhaustive staining of paddlefish chromosomes combined with cytogenetic mapping of ribosomal genes and Hox paralogs and with microsatellite data, brings a closer look at results of the process of rediploidization in the course of paddlefish genome evolution. We show a partial rediploidization represented by a complex mosaic structure comparable with segmental paleotetraploidy revealed in sturgeons (Acipenseridae). Sturgeons and paddlefishes with their high propensity for whole genome duplication thus offer suitable animal model systems to further explore evolutionary processes that were shaping the early evolution of all vertebrates

Applications of Direct Injection Soft Chemical Ionisation-Mass Spectrometry for the Detection of Pre-blast Smokeless Powder Organic Additives

Analysis of smokeless powders is of interest from forensics and security perspectives. This article reports the detection of smokeless powder organic additives (in their pre-detonation condition), namely the stabiliser diphenylamine and its derivatives 2-nitrodiphenylamine and 4-nitrodiphenylamine, and the additives (used both as stabilisers and plasticisers) methyl centralite and ethyl centralite, by means of swab sampling followed by thermal desorption and direct injection soft chemical ionisation-mass spectrometry. Investigations on the product ions resulting from the reactions of the reagent ions H3O+ and O2+ with additives as a function of reduced electric field are reported. The method was comprehensively evaluated in terms of linearity, sensitivity and precision. For H3O+, the limits of detection (LoD) are in the range of 41-88 pg of additive, for which the accuracy varied between 1.5 and 3.2%, precision varied between 3.7 and 7.3% and linearity showed R20.9991. For O2+, LoD are in the range of 72 to 1.4 ng, with an accuracy of between 2.8 and 4.9% and a precision between 4.5 and 8.6% and R20.9914. The validated methodology was applied to the analysis of commercial pre-blast gun powders from different manufacturers.(VLID)4826148Accepted versio

Mapping nn grid points onto a square forces an arbitrarily large Lipschitz constant

We prove that the regular $n\times n$ square grid of points in the integer lattice $\mathbb{Z}^{2}$ cannot be recovered from an arbitrary $n^{2}$-element subset of $\mathbb{Z}^{2}$ via a mapping with prescribed Lipschitz constant (independent of $n$). This answers negatively a question of Feige from 2002. Our resolution of Feige's question takes place largely in a continuous setting and is based on some new results for Lipschitz mappings falling into two broad areas of interest, which we study independently. Firstly the present work contains a detailed investigation of Lipschitz regular mappings on Euclidean spaces, with emphasis on their bilipschitz decomposability in a sense comparable to that of the well known result of Jones. Secondly, we build on work of Burago and Kleiner and McMullen on non-realisable densities. We verify the existence, and further prevalence, of strongly non-realisable densities inside spaces of continuous functions.Comment: 60 pages (43 pages of the main part, 13 pages of appendices), 10 figures. This is a revised version according to referees' comments. Our version of the proof of the theorem about bilipschitz decomposition of Lipschitz regular mappings was greatly simplified. To appear in GAF

Non-Nudgable Subgroups of Permutations

Motivated by a problem from behavioral economics, we study subgroups of permutation groups that have a certain strong symmetry. Given a fixed permutation, consider the set of all permutations with disjoint inversion sets. The group is called non-nudgable, if the cardinality of this set always remains the same when replacing the initial permutation with its inverse. It is called nudgable otherwise. We show that all full permutation groups, standard dihedral groups, half of the alternating groups, and any abelian subgroup are non-nudgable. In the right probabilistic sense, it is thus quite likely that a randomly generated subgroup is non-nudgable. However, the other half of the alternating groups are nudgable. We also construct a smallest possible nudgable group, a 6-element subgroup of the permutation group on 4 elements.Comment: new version contains some simplifications and extension

Intermediate scattering function of an anisotropic active Brownian particle

Various challenges are faced when animalcules such as bacteria, protozoa, algae, or sperms move autonomously in aqueous media at low Reynolds number. These active agents are subject to strong stochastic fluctuations, that compete with the directed motion. So far most studies consider the lowest order moments of the displacements only, while more general spatio-temporal information on the stochastic motion is provided in scattering experiments. Here we derive analytically exact expressions for the directly measurable intermediate scattering function for a mesoscopic model of a single, anisotropic active Brownian particle in three dimensions. The mean-square displacement and the non-Gaussian parameter of the stochastic process are obtained as derivatives of the intermediate scattering function. These display different temporal regimes dominated by effective diffusion and directed motion due to the interplay of translational and rotational diffusion which is rationalized within the theory. The most prominent feature of the intermediate scattering function is an oscillatory behavior at intermediate wavenumbers reflecting the persistent swimming motion, whereas at small length scales bare translational and at large length scales an enhanced effective diffusion emerges. We anticipate that our characterization of the motion of active agents will serve as a reference for more realistic models and experimental observations.Comment: 10 pages, 4 figure

Regularity of the speed of biased random walk in a one-dimensional percolation model

We consider biased random walks on the infinite cluster of a conditional bond percolation model on the infinite ladder graph. Axelsson-Fisk and H\"aggstr\"om established for this model a phase transition for the asymptotic linear speed $\overline{\mathrm{v}}$ of the walk. Namely, there exists some critical value $\lambda_{\mathrm{c}}>0$ such that $\overline{\mathrm{v}}>0$ if $\lambda\in (0,\lambda_{\mathrm{c}})$ and $\overline{\mathrm{v}}=0$ if $\lambda>\lambda_{\mathrm{c}}$. We show that the speed $\overline{\mathrm{v}}$ is continuous in $\lambda$ on the interval $(0,\lambda_{\mathrm{c}})$ and differentiable on $(0,\lambda_{\mathrm{c}}/2)$. Moreover, we characterize the derivative as a covariance. For the proof of the differentiability of $\overline{\mathrm{v}}$ on $(0,\lambda_{\mathrm{c}}/2)$, we require and prove a central limit theorem for the biased random walk. Additionally, we prove that the central limit theorem fails to hold for $\lambda \geq \lambda_{\mathrm{c}}/2$

Multi-layered simulations at the heart of workflow enactment on clouds

Scientific workflow systems face new challenges when supporting Cloud computing, as the information on the state of the used infrastructures is much less detailed than before. Thus, organising virtual infrastructures in a way that not only supports the workflow execution but also optimises it for several service level objectives (e.g. maximum energy consumption limit, cost, reliability, availability) become reliant on good Cloud modelling and prediction information. While simulators were successfully aiding research on such workflow management systems, the currently available Cloud related simulation toolkits suffer from several issues (e.g. scalability and narrow scope) that hinder their applicability. To address these issues, this article introduces techniques for unifying two existing simulation toolkits by first analysing the problems with the current simulators, and then by illustrating the problems faced by workflow systems. We use for this purpose the example of the ASKALON environment, a scientific workflow composition and execution tool for cloud and grid environments. We illustrate the advantages of a workflow system with directly integrated simulation back-end and how the unification of the selected simulators does not affect the overall workflow execution simulation performance. Copyright © 2015 John Wiley & Sons, Ltd

Fine-Grain Interoperability of Scientific Workflows in Distributed Computing Infrastructures

Today there exist a wide variety of scientific workflow management systems, each designed to fulfill the needs of a certain scientific community. Unfortunately, once a workflow application has been designed in one particular system it becomes very hard to share it with users working with different systems. Portability of workflows and interoperability between current systems barely exists. In this work, we present the fine-grained interoperability solution proposed in the SHIWA European project that brings together four representative European workflow systems: ASKALON, MOTEUR, WS-PGRADE, and Triana. The proposed interoperability is realised at two levels of abstraction: abstract and concrete. At the abstract level, we propose a generic Interoperable Workflow Intermediate Representation (IWIR) that can be used as a common bridge for translating workflows between different languages independent of the underlying distributed computing infrastructure. At the concrete level, we propose a bundling technique that aggregates the abstract IWIR representation and concrete task representations to enable workflow instantiation, execution and scheduling. We illustrate case studies using two real-workflow applications designed in a native environment and then translated and executed by a foreign workflow system in a foreign distributed computing infrastructure. © 2013 Springer Science+Business Media Dordrecht

Atomically resolved phase transition of fullerene cations solvated in helium droplets

Helium has a unique phase diagram and below 25 bar it does not form a solid even at the lowest temperatures. Electrostriction leads to the formation of a solid layer of helium around charged impurities at much lower pressures in liquid and superfluid helium. These so-called ‘Atkins snowballs’ have been investigated for several simple ions. Here we form HenC60+ complexes with n exceeding 100 via electron ionization of helium nanodroplets doped with C60. Photofragmentation of these complexes is measured by merging a tunable narrow- bandwidth laser beam with the ions. A switch from red- to blueshift of the absorption frequency of HenC60+ on addition of He atoms at n=32 is associated with a phase transition in the attached helium layer from solid to partly liquid (melting of the Atkins snowball). Elaborate molecular dynamics simulations using a realistic force field and including quantum effects support this interpretation

"Libraries.Solidarity.Society" – Schritte zu einer Intensivierung der Kooperation zwischen den deutschsprachigen und internationalen Bibliotheksverbänden

Libraries Solidarity Society. Notes on the IFLA World Library and Information Congress 2017, held in Wroclaw from 19th to 25th of August