2,192 research outputs found

    The Discursive Construction of Innovation Policy in Peripheralising Estonia

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    An innovation-driven agenda in regional development policy has emerged in the European Union against the backdrop of peripheralisation, especially in Central and Eastern Europe. Using a discursive analytical framework, the article investigates the ways in which peripheralisation is manifested through language, practices and power-rationalities in Estonian innovation policy discourse. The analysis is footed on key strategic policy documents and semi-structured expert interviews. Findings suggest that Estonian innovation policy’s main narrative of the ‘knowledge-based economy’ accepts growing disparities on sub-national level in order to overcome peripherality at European scale and narrows the range of policy solutions perceived as suitable

    Glass-Like Random Catalogues for Two-Point Estimates on the Light Cone

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    We introduce grlic, a publicly available Python tool for generating glass-like point distributions with a radial density profile n(r)n(r) as it is observed in large-scale surveys of galaxy distributions on the past light cone. Utilising these glass-like catalogues, we assess the bias and variance of the Landy-Szalay (LS) estimator of the first three two-point correlation function (2PCF) multipoles in halo and particle catalogues created with the cosmological N-body code gevolution. Our results demonstrate that the LS estimator calculated with the glass catalogues is biased by less than 10410^{-4} with respect to the estimate derived from Poisson-sampled random catalogues, for all multipoles considered and on all but the smallest scales. Additionally, the estimates derived from glass-like catalogues exhibit significantly smaller standard deviation σ\sigma than estimates based on commonly used Poisson-sampled random catalogues of comparable size. The standard deviation of the estimate depends on a power of the number of objects NRN_R in the random catalogue; we find a power law σNR0.9\sigma \propto N_R^{-0.9} for glass-like random catalogues as opposed to σNR0.48\sigma \propto N_R^{-0.48} using Poisson-sampled random catalogues. Given a required precision, this allows for a much reduced number of objects in the glass-like random catalogues used for the LS estimate of the 2PCF multipoles, significantly reducing the computational costs of each estimate.Comment: 16 pages, 14 figure

    Phase-field simulations of multi-component solidification and coarsening based on thermodynamic datasets

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    The utilization of thermodynamic and mobility data plays a major role in phase-field modeling. This work discusses different formulations for the thermodynamic quantities of a grand potential model along with practices to determine parameters from datasets. The framework is used to study solidification of Al-Si-Mg for a variation of composition, diffusivities and surface energy anisotropies. To verify the simulations, they are compared with solidification theories

    Phase-field simulations of multi-component solidification and coarsening based on thermodynamic datasets

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    The utilization of thermodynamic and mobility data plays a major role in quantitative phase-field modeling. The present thesis discusses this topic on a theoretical level and deals with the application of such data for phase-field studies. These studies cover the solidification of Al-Si-Mg for a variation of composition, diffusion coefficients and surface energy anisotropies, as well as the process of coarsening in the system Fe-Cu

    On the Geographic Allocation of Open Source Software Activities

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    Open source software (OSS) is marked by free access to the software and its source code. OSS is developed by a 'community' consisting of thousands of contributors from all over the world. Some research was undertaken in order to analyze how global the OSS community actually is, i.e. analyze the geographic origin of OSS developers. But as members of the OSS community differ in their activity levels, information about the allocation of activities are of importance. Our paper contributes to this as we analyze not only the geographic origin of (active) developers but also the geographic allocation of OSS activities. The paper is based on data from the SourceForge research Data Archive, referring to 2006. We exploit information about the developers' IP address, email address and indicated time-zone. This enables us to properly assign 1.3 million OSS developers from SourceForge to their countries, that are 94% of all registered ones in 2006. In addition we have information about the number of posted messages which is a good proxy for activity of each developer. Thus we can provide a detailed picture of the world-wide allocation of open source activities. Such country data about the supply-side of OSS is a valuable stock for both, cross-country studies on OSS, as well as country-specific research and policy advice.Open Source Software, Geographical Location, Open Source Activities

    RNA-dependent association with myosin IIA promotes F-actin-guided trafficking of the ELAV-like protein HuR to polysomes

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    The role of the mRNA-binding protein human antigen R (HuR) in stabilization and translation of AU-rich elements (ARE) containing mRNAs is well established. However, the trafficking of HuR and bound mRNA cargo, which comprises a fundamental requirement for the aforementioned HuR functions is only poorly understood. By administering different cytoskeletal inhibitors, we found that the protein kinase Cδ (PKCδ)-triggered accumulation of cytoplasmic HuR by Angiotensin II (AngII) is an actin-myosin driven process functionally relevant for stabilization of ARE-bearing mRNAs. Furthermore, we show that the AngII-induced recruitment of HuR and its bound mRNA from ribonucleoprotein particles to free and cytoskeleton bound polysomes strongly depended on an intact actomyosin cytoskeleton. In addition, HuR allocation to free and cytoskeletal bound polysomes is highly sensitive toward RNase and PPtase and structurally depends on serine 318 (S318) located within the C-terminal RNA recognition motif (RRM3). Conversely, the trafficking of the phosphomimetic HuRS318D, mimicking HuR phosphorylation at S318 by the PKCδ remained PPtase resistant. Co-immunoprecipitation experiments with truncated HuR proteins revealed that the stimulus-induced association of HuR with myosin IIA is strictly RNA dependent and mediated via the RRM3. Our data implicate a microfilament dependent transport of HuR, which is relevant for stimulus-induced targeting of ARE-bearing mRNAs from translational inactive ribonucleoprotein particles to polysomes

    A comprehensive analysis of the importance of translation initiation factors for Haloferax volcanii applying deletion and conditional depletion mutants

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    Translation is an important step in gene expression. The initiation of translation is phylogenetically diverse, since currently five different initiation mechanisms are known. For bacteria the three initiation factors IF1 – IF3 are described in contrast to archaea and eukaryotes, which contain a considerably higher number of initiation factor genes. As eukaryotes and archaea use a non-overlapping set of initiation mechanisms, orthologous proteins of both domains do not necessarily fulfill the same function. The genome of Haloferax volcanii contains 14 annotated genes that encode (subunits of) initiation factors. To gain a comprehensive overview of the importance of these genes, it was attempted to construct single gene deletion mutants of all genes. In 9 cases single deletion mutants were successfully constructed, showing that the respective genes are not essential. In contrast, the genes encoding initiation factors aIF1, aIF2γ, aIF5A, aIF5B, and aIF6 were found to be essential. Factors aIF1A and aIF2β are encoded by two orthologous genes in H. volcanii. Attempts to generate double mutants failed in both cases, indicating that also these factors are essential. A translatome analysis of one of the single aIF2β deletion mutants revealed that the translational efficiency of the second ortholog was enhanced tenfold and thus the two proteins can replace one another. The phenotypes of the single deletion mutants also revealed that the two aIF1As and aIF2βs have redundant but not identical functions. Remarkably, the gene encoding aIF2α, a subunit of aIF2 involved in initiator tRNA binding, could be deleted. However, the mutant had a severe growth defect under all tested conditions. Conditional depletion mutants were generated for the five essential genes. The phenotypes of deletion mutants and conditional depletion mutants were compared to that of the wild-type under various conditions, and growth characteristics are discussed

    Integrated multi vector vortex beam generator

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    A novel method to generate and manipulate vector vortex beams in an integrated, ring resonator based geometry is proposed. We show numerically that a ring resonator, with an appropriate grating, addressed by a vertically displaced access waveguide emits a complex optical field. The emitted beam possesses a specific polarization topology, and consequently a transverse intensity profile and orbital angular momentum. We propose a combination of several concentric ring resonators, addressed with different bus guides, to generate arbitrary orbital angular momentum qudit states, which could potentially be used for classical and quantum communications. Finally, we demonstrate numerically that this device works as an orbital angular momentum sorter with an average cross-talk of -10 dB between different orbital angular momentum channels.Comment: 8 pages, 7 figure
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