3,761 research outputs found

    Weight-Training Injuries: A Systematic Review of the Etiology, Risk Factors, and Interventions

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    Please view abstract in the attached PDF fil

    Entwicklung einer Vorgehensweise zur Bestimmung und Verifikation von WĂ€rmeĂŒbergangsparametern aus CFD Simulationen von Trockenkupplungssystemen = Development of an Estimation and Verification Approach for Heat Transfer Parameters of DryClutch Systems Obtained from CFD Simulations

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    Die Dimensionierung einer Kupplung fĂŒr manuelle Schaltgetriebe ist stark von den Temperaturen im Friktionskontakt abhĂ€ngig. Das richtige VerstĂ€ndnis fĂŒr die Einstufung der WĂ€rmeĂŒbertragungsmechanismen und der Randbedingungen ist eine SchlĂŒsselstelle in der Ermittlung der KupplungsgrĂ¶ĂŸe. Diese Arbeit widmet sich der Charakterisierung des WĂ€rmeĂŒbergangs von Trockenkupplungssystemen, dem Prozess der Ergebnisvereinfachung und ?validierung, die von einer CFD Simulation generiert wurden

    Zebrafish embryonic explants undergo genetically encoded self-assembly

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    Embryonic stem cell cultures are thought to self-organize into embryoid bodies, able to undergo symmetry-breaking, germ layer specification and even morphogenesis. Yet, it is unclear how to reconcile this remarkable self-organization capacity with classical experiments demonstrating key roles for extrinsic biases by maternal factors and/or extraembryonic tissues in embryogenesis. Here, we show that zebrafish embryonic tissue explants, prepared prior to germ layer induction and lacking extraembryonic tissues, can specify all germ layers and form a seemingly complete mesendoderm anlage. Importantly, explant organization requires polarized inheritance of maternal factors from dorsal-marginal regions of the blastoderm. Moreover, induction of endoderm and head-mesoderm, which require peak Nodal-signaling levels, is highly variable in explants, reminiscent of embryos with reduced Nodal signals from the extraembryonic tissues. Together, these data suggest that zebrafish explants do not undergo bona fide self-organization, but rather display features of genetically encoded self-assembly, where intrinsic genetic programs control the emergence of order

    First principles calculation of structural and magnetic properties for Fe monolayers and bilayers on W(110)

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    Structure optimizations were performed for 1 and 2 monolayers (ML) of Fe on a 5 ML W(110) substrate employing the all-electron full-potential linearized augmented plane-wave (FP-LAPW) method. The magnetic moments were also obtained for the converged and optimized structures. We find significant contractions (∌\sim 10 %) for both the Fe-W and the neighboring Fe-Fe interlayer spacings compared to the corresponding bulk W-W and Fe-Fe interlayer spacings. Compared to the Fe bcc bulk moment of 2.2 ÎŒB\mu_B, the magnetic moment for the surface layer of Fe is enhanced (i) by 15% to 2.54 ÎŒB\mu_B for 1 ML Fe/5 ML W(110), and (ii) by 29% to 2.84 ÎŒB\mu_B for 2 ML Fe/5 ML W(110). The inner Fe layer for 2 ML Fe/5 ML W(110) has a bulk-like moment of 2.3 ÎŒB\mu_B. These results agree well with previous experimental data

    The Biological Standard of Living in the two Germanies.

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    Physical stature is used as a proxy for the biological standard of living in the two Germanies before and after unification in an analysis of a cross-sectional sample (1998) of adult heights, as well as among military recruits of the 1990s. West Germans tended to be taller than East Germans throughout the period under consideration. Contrary to official proclamations of a classless society, there were substantial social differences in physical stature in East-Germany. Social differences in height were greater in the East among females, and less among males than in the West. The difficulties experienced by the East-German population after 1961 is evident in the increase in social inequality of physical stature thereafter, as well as in the increasing gap relative to the height of the West-German population. After unification, however, there is a tendency for East-German males, but not of females, to catch up with their West-German counterparts

    Evolutionary Algorithms with Linkage Information for Feature Selection in Brain Computer Interfaces

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    Abstract Brain Computer Interfaces are an essential technology for the advancement of prosthetic limbs, but current signal acquisition methods are hindered by a number of factors, not least, noise. In this context, Feature Selection is required to choose the important signal features and improve classifier accuracy. Evolutionary algorithms have proven to outperform filtering methods (in terms of accuracy) for Feature Selection. This paper applies a single-point heuristic search method, Iterated Local Search (ILS), and compares it to a genetic algorithm (GA) and a memetic algorithm (MA). It then further attempts to utilise Linkage between features to guide search operators in the algorithms stated. The GA was found to outperform ILS. Counter-intuitively, linkage-guided algorithms resulted in higher classification error rates than their unguided alternatives. Explanations for this are explored

    Critical Susceptibility Exponent Measured from Fe/W(110) Bilayers

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    The critical phase transition in ferromagnetic ultrathin Fe/W(110) films has been studied using the magnetic ac susceptibility. A statistically objective, unconstrained fitting of the susceptibility is used to extract values for the critical exponent (gamma), the critical temperature Tc, the critical amplitude (chi_o) and the range of temperature that exhibits power-law behaviour. A fitting algorithm was used to simultaneously minimize the statistical variance of a power law fit to individual experimental measurements of chi(T). This avoids systematic errors and generates objective fitting results. An ensemble of 25 measurements on many different films are analyzed. Those which permit an extended fitting range in reduced temperature lower than approximately .00475 give an average value gamma=1.76+-0.01. Bilayer films give a weighted average value of gamma = 1.75+-0.02. These results are in agreement with the -dimensional Ising exponent gamma= 7/4. Measurements that do not exhibit power-law scaling as close to Tc (especially films of thickness 1.75ML) show a value of gamma higher than the Ising value. Several possibilities are considered to account for this behaviour.Comment: -Submitted to Phys. Rev. B -Revtex4 Format -6 postscript figure
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