1,752 research outputs found

    Seafarers’ experiences during the COVID-19 pandemic

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    This report provides an overview of preliminary findings of a study on the experiences of seafarers during the COVID-19 pandemic. The purpose was to examine the impact of the pandemic on seafarers’ work and life on board as well as on their mental health and exhaustion, and identify factors that may mitigate the negative impact of the pandemichttps://commons.wmu.se/lib_reports/1080/thumbnail.jp

    Exponential-Potential Scalar Field Universes I: The Bianchi I Models

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    We obtain a general exact solution of the Einstein field equations for the anisotropic Bianchi type I universes filled with an exponential-potential scalar field and study their dynamics. It is shown, in agreement with previous studies, that for a wide range of initial conditions the late-time behaviour of the models is that of a power-law inflating FRW universe. This property, does not hold, in contrast, when some degree of inhomogeneity is introduced, as discussed in our following paper II.Comment: 16 pages, Plain LaTeX, 1 Figure to be sent on request, to appear in Phys. Rev.

    Effects of Alloying Elements and Cold Work on the Redistribution of Hydrogen in Zirconium under a Temperature Gradient

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    Effects of alloying elements (beryllium, hafnium, niobium, tin and yttrium) and of cold-swaging on the redistribution of hydrogen in zirconium with various initial hydrogen concentrations have been examined after anneals under given temperature differences. For low hydrogen concentration, the alloying elements did not greatly affect the value of the heat of transport, except for the beta-martensite Zr/1 wt% Nb alloy which showed a low value. Cold-swaging enhanced the migration of hydrogen toward the cold end. The heat of transport of the worked specimens could not be calculated accurately. For high hydrogen concentration, the α/(α+Ύ) interface moved toward the cold end. As the initial concentrations were different from alloy to alloy, a normalization process was employed. The resulting comparison showed that niobium accelerated the movement of the interface. This was attributed to the fine grain size of the alloy. The movement of the interface was also enhanced by cold-swaging which probably produced many defects and elongated grain boundaries along the temperature gradient, thereby accelerating diffusion of hydrogen toward the cold end

    Coupled quintessence and curvature-assisted acceleration

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    Spatially homogeneous models with a scalar field non-minimally coupled to the space-time curvature or to the ordinary matter content are analysed with respect to late-time asymptotic behaviour, in particular to accelerated expansion and isotropization. It is found that a direct coupling to the curvature leads to asymptotic de Sitter expansion in arbitrary exponential potentials, thus yielding a positive cosmological constant although none is apparent in the potential. This holds true regardless of the steepness of the potential or the smallness of the coupling constant. For matter-coupled scalar fields, the asymptotics are obtained for a large class of positive potentials, generalizing the well-known cosmic no-hair theorems for minimal coupling. In this case it is observed that the direct coupling to matter does not impact the late-time dynamics essentially.Comment: 17 pages, no figures. v2: typos correcte

    Liquefied Natural Gas as a Marine Fuel: The Case of the Baltic Sea Region

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    https://commons.wmu.se/lib_chapters/1011/thumbnail.jp

    Expanding the Use of Liquefied Natural Gas in the Baltic Sea Region via Tailor-made Training Activities

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    https://commons.wmu.se/lib_chapters/1010/thumbnail.jp

    {\it Ab initio} calculations of magnetic structure and lattice dynamics of Fe/Pt multilayers

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    The magnetization distribution, its energetic characterization by the interlayer coupling constants and lattice dynamics of (001)-oriented Fe/Pt multilayers are investigated using density functional theory combined with the direct method to determine phonon frequencies. It is found that ferromagnetic order between consecutive Fe layers is favoured, with the enhanced magnetic moments at the interface. The bilinear and biquadratic coupling coefficients between Fe layers are shown to saturate fast with increasing thickness of nonmagnetic Pt layers which separate them. The phonon calculations demonstrate a rather strong dependence of partial iron phonon densities of states on the actual position of Fe monolayer in the multilayer structure.Comment: 7 pages, 8 figure

    Intermediate inflation and the slow-roll approximation

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    It is shown that spatially homogeneous solutions of the Einstein equations coupled to a nonlinear scalar field and other matter exhibit accelerated expansion at late times for a wide variety of potentials VV. These potentials are strictly positive but tend to zero at infinity. They satisfy restrictions on Vâ€Č/VV'/V and Vâ€Čâ€Č/Vâ€ČV''/V' related to the slow-roll approximation. These results generalize Wald's theorem for spacetimes with positive cosmological constant to those with accelerated expansion driven by potentials belonging to a large class.Comment: 19 pages, results unchanged, additional backgroun

    Inhibition of NF-ÎșB-mediated signaling by the cyclin-dependent kinase inhibitor CR8 overcomes pro-survival stimuli to induce apoptosis in chronic lymphocytic leukemia cells

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    Purpose: Chronic lymphocytic leukemia (CLL) is currently incurable with standard chemotherapeutic agents, highlighting the need for novel therapies. Overcoming proliferative and cytoprotective signals generated within the microenvironment of lymphoid organs is essential for limiting CLL progression and ultimately developing a cure. Experimental Design: We assessed the potency of cyclin-dependent kinase (CDK) inhibitor CR8, a roscovitine analog, to induce apoptosis in primary CLL from distinct prognostic subsets using flow cytometry–based assays. CLL cells were cultured in in vitro prosurvival and proproliferative conditions to mimic microenvironmental signals in the lymphoid organs, to elucidate the mechanism of action of CR8 in quiescent and proliferating CLL cells using flow cytometry, Western blotting, and quantitative real-time PCR. Results: CR8 was 100-fold more potent at inducing apoptosis in primary CLL cells than roscovitine, both in isolated culture and stromal-coculture conditions. Importantly, CR8 induced apoptosis in CD40-ligated CLL cells and preferentially targeted actively proliferating cells within these cultures. CR8 treatment induced downregulation of the antiapoptotic proteins Mcl-1 and XIAP, through inhibition of RNA polymerase II, and inhibition of NF-ÎșB signaling at the transcriptional level and through inhibition of the inhibitor of IÎșB kinase (IKK) complex, resulting in stabilization of IÎșBα expression. Conclusions: CR8 is a potent CDK inhibitor that subverts pivotal prosurvival and proproliferative signals present in the tumor microenvironment of CLL patient lymphoid organs. Our data support the clinical development of selective CDK inhibitors as novel therapies for CLL
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