876 research outputs found

    Metastable states of a flux line lattice studied by transport and Small Angle Neutron Scattering

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    Flux Lines Lattice (FLL) states have been studied using transport measurements and Small Angle Neutron Scattering in low Tc_c materials. In Pb-In, the bulk dislocations in the FLL do not influence the transport properties. In Fe doped NbSe2_{2}, transport properties can differ after a Field Cooling (FC) or a Zero Field Cooling (ZFC) procedure, as previously reported. The ZFC FLL is found ordered with narrow Bragg Peaks and is linked to a linear V(I) curve and to a superficial critical current. The FC FLL pattern exhibits two Bragg peaks and the corresponding V(I) curve shows a S-shape. This can be explained by the coexistence of two ordered FLL slightly tilted from the applied field direction by different superficial currents. These currents are wiped out when the transport current is increased.Comment: accepted for publication in Phys. Rev.

    Integration of nonmarket and market activities in cross-border mergers and acquisitions

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    Drawing on the resource dependence theory and the resource-based view, this paper investigates the interactions between market and nonmarket activities of firms in the context of the post-merger integration phase in cross-border mergers and acquisitions (M&As). Based on a cross-country survey of 111 M&A practitioners who were personally involved in cross-border M&As around the world, we test seven hypotheses on various market and nonmarket aspects of post-merger integration. We find a positive correlation between buffering strategies and adaptive capabilities in the nonmarket environment, and between bridging and adaptive capabilities in the market environment. However, we could not find any significant correlation between buffering and adaptive capabilities in the market environment, and bridging and adaptive capabilities in the nonmarket environment. We also find that adaptability in the nonmarket environment is positively correlated with adaptability in the market environment, and in turn adaptability in the market environment leads to positive organizational performance of a cross border M&A. These results provide further support for the value of the alignment between market and nonmarket activities and help to fill a gap in the literature on the market-nonmarket interactions in post-merger integration

    Longitudinal and transverse noise in a moving Vortex Lattice

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    We have studied the longitudinal and the transverse velocity fluctuations of a moving vortex lattice (VL) driven by a transport current. They exhibit both the same broad spectrum and the same order of magnitude. These two components are insensitive to the velocity and to a small bulk perturbation. This means that no bulk averaging over the disorder and no VL crystallization are observed. This is consistently explained referring to a previously proposed noisy flow of surface current whose elementary fluctuator is measured isotropic.Comment: accepted for publication in Phys Rev

    Experimental study of the correlation length of critical-current fluctuations in the presence of surface disorder: Probing vortex long-range interactions

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    We report on critical currents and voltage noise measurements in Niobium strips in the superconducting state, in the presence of a bulk vortex lattice (B<BC2B < B_{C2}) and in the surface superconducting state (Bc2<B<BC3B_{c2}< B < B_{C3}). For homogeneous surfaces, the correlation length of the current fluctuations can be associated with the electromagnetic skin depth of vortex superficial instabilities. The modification of the surface state by means of low energy irradiation induces a strong modification of the critical current and of the noise. The appearance of a corner frequency in the spectral domain can be linked with the low wave-vectors of the artificial corrugation. Since this latter occurs only for B<BC2B < B_{C2}, we propose that the long-range interactions allow the correlation length to extend up to values imposed by the surface topography.Comment: accepted for publication in PR

    Mimivirus in Pneumonia Patients

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    Mimivirus, the largest virus known to date, is an amebal pathogen like Legionella spp. When mimivirus was used as an antigen in a migration inhibition factor assay, seroconversion was found in patients with both community- and hospital-acquired pneumonia. Mimivirus DNA was found in respiratory samples of patients with hospital-acquired pneumonia

    Bioengineering Dermo-Epidermal Skin Grafts with Blood and Lymphatic Capillaries

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    The first bioengineered, autologous, dermo-epidermal skin grafts are presently undergoing clinical trials; hence, it is reasonable to envisage the next clinical step at the forefront of plastic and burn surgery, which is the generation of autologous skin grafts that contain vascular plexuses, preformed in vitro. As the importance of the blood, and particularly the lymphatic vascular system, is increasingly recognized, it is attractive to engineer both human blood and lymphatic vessels in one tissue or organ graft. We show here that functional lymphatic capillaries can be generated using three-dimensional hydrogels. Like normal lymphatics, these capillaries branch, form lumen, and take up fluid in vitro and in vivo after transplantation onto immunocompromised rodents. Formation of lymphatic capillaries could be modulated by both lymphangiogenic and anti-lymphangiogenic stimuli, demonstrating the potential usefulness of this system for in vitro testing. Blood and lymphatic endothelial cells never intermixed during vessel development, nor did blood and lymphatic capillaries anastomose under the described circumstances. After transplantation of the engineered grafts, the human lymphatic capillaries anastomosed to the nude rat's lymphatic plexus and supported fluid drainage. Successful preclinical results suggest that these skin grafts could be applied on patients suffering from severe skin defects

    Molecular characterisation of congenital myasthenic syndromes in Southern Brazil

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    Objective To perform genetic testing of patients with congenital myasthenic syndromes (CMS) from the Southern Brazilian state of Parana. Patients and methods Twenty-five CMS patients from 18 independent families were included in the study. Known CMS genes were sequenced and restriction digest for the mutation RAPSN p.N88K was performed in all patients. Results We identified recessive mutations of CHRNE in ten families, mutations in DOK7 in three families and mutations in COLQ, CHRNA1 and CHRNB1 in one family each. The mutation CHRNE c. 70insG was found in six families. We have repeatedly identified this mutation in patients from Spain and Portugal and haplotype studies indicate that CHRNE c. 70insG derives from a common ancestor. Conclusions Recessive mutations in CHRNE are the major cause of CMS in Southern Brazil with a common mutation introduced by Hispanic settlers. The second most common cause is mutations in DOK7. The minimum prevalence of CMS in Parana is 0.18/100 000

    Molecular characterisation of congenital myasthenic syndromes in Southern Brazil

    Get PDF
    Objective To perform genetic testing of patients with congenital myasthenic syndromes (CMS) from the Southern Brazilian state of Parana. Patients and methods Twenty-five CMS patients from 18 independent families were included in the study. Known CMS genes were sequenced and restriction digest for the mutation RAPSN p.N88K was performed in all patients. Results We identified recessive mutations of CHRNE in ten families, mutations in DOK7 in three families and mutations in COLQ, CHRNA1 and CHRNB1 in one family each. The mutation CHRNE c. 70insG was found in six families. We have repeatedly identified this mutation in patients from Spain and Portugal and haplotype studies indicate that CHRNE c. 70insG derives from a common ancestor. Conclusions Recessive mutations in CHRNE are the major cause of CMS in Southern Brazil with a common mutation introduced by Hispanic settlers. The second most common cause is mutations in DOK7. The minimum prevalence of CMS in Parana is 0.18/100 000
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