236 research outputs found

    Multilinear Eigenfunction Estimates And Global Existence For The Three Dimensional Nonlinear Schr\"Odinger Equations

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    We study nonlinear Schr\"odinger equations, posed on a three dimensional Riemannian manifold MM. We prove global existence of strong H1H^1 solutions on M=S3M=S^3 and M=S2×S1M=S^2\times S^1 as far as the nonlinearity is defocusing and sub-quintic and thus we extend the results of Ginibre-Velo and Bourgain who treated the cases of the Euclidean space R3\R^3 and the flat torus \T^3 respectively. The main ingredient in our argument is a new set of multilinear estimates for spherical harmonics.Comment: Lemma 4.6 in the previous version was false, we made slight modifications to use only a weaker version of this lemm

    Random data Cauchy theory for supercritical wave equations II : A global existence result

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    We prove that the subquartic wave equation on the three dimensional ball Θ\Theta, with Dirichlet boundary conditions admits global strong solutions for a large set of random supercritical initial data in s<1/2Hs(Θ)\cap_{s<1/2} H^s(\Theta). We obtain this result as a consequence of a general random data Cauchy theory for supercritical wave equations developed in our previous work \cite{BT2} and invariant measure considerations which allow us to obtain also precise large time dynamical informations on our solutions

    Guidelines for assessing favourable conservation status of Natura 2000 species and habitat types in Bulgaria

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    This executive summary describes the methodology for assessing the favourable conservation status of N2000 habitats and species on site level in Bulgaria and gives guidelines for its application. The methodology was developed in the frame of the BBI/Matra project 2006/014 “Favourable Conservation Status of Natura 2000 Habitat types and Species in Bulgaria”. The project was generously supported by the Dutch government under the BBI/Matra programme, which is a combination of two international policy programs of the Dutch government. The objectives and financial resources of the BBI/Matra Programme fall within the remit of the Matra Social Transformation Program of the Ministry of Foreign Affairs and under the International Policy Program on Biodiversity of the Ministry of Agriculture, Nature and Food Quality

    Synthesis and crystal structure determination of YCo1−xFexO3 (x = 0,0.33, 0.5, 0.67 and 1) perovskites

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    The results on synthesis, crystal structure determination and calculation of crystallochemical parameters of YCo1−xFexO3 (x = 0, 0.33, 0.5, 0.67 and 1) perovskites are presented in this work. The compounds within this series were synthesized by solution combustion method using two different fuels: urea and citric acid. It was found that iron-containing perovskites, obtained by citric acid as a fuel are of better quality and crystallinity. All the compounds crystallize in Pnma space group with Z = 4. According to the structure and the calculated crystallochemical parameters, the coordination number of Y3+ in these perovskites is 8. The unit cell parameter relationship is of O−type suggesting that the main reason for distortion of ideal perovskite structure is the octahedral tilting. The deformation of the octahedrons, as well as the tilting angles, are increasing with the increasing content of Fe3+ but the calculated global instability indices (GII) show that the stability of the perovskite structure is increasing with increasing of the Fe3+ content

    APRIL:TACI axis is dispensable for the immune response to rabies vaccination.

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    There is significant need to develop a single-dose rabies vaccine to replace the current multi-dose rabies vaccine regimen and eliminate the requirement for rabies immune globulin in post-exposure settings. To accomplish this goal, rabies virus (RABV)-based vaccines must rapidly activate B cells to secrete antibodies which neutralize pathogenic RABV before it enters the CNS. Increased understanding of how B cells effectively respond to RABV-based vaccines may improve efforts to simplify post-exposure prophylaxis (PEP) regimens. Several studies have successfully employed the TNF family cytokine a proliferation-inducing ligand (APRIL) as a vaccine adjuvant. APRIL binds to the receptors TACI and B cell maturation antigen (BCMA)-expressed by B cells in various stages of maturation-with high affinity. We discovered that RABV-infected primary murine B cells upregulate APRIL ex vivo. Cytokines present at the time of antigen exposure affect the outcome of vaccination by influencing T and B cell activation and GC formation. Therefore, we hypothesized that the presence of APRIL at the time of RABV-based vaccine antigen exposure would support the generation of protective antibodies against RABV glycoprotein (G). In an effort to improve the response to RABV vaccination, we constructed and characterized a live recombinant RABV-based vaccine vector which expresses murine APRIL (rRABV-APRIL). Immunogenicity testing in mice demonstrated that expressing APRIL from the RABV genome does not impact the primary antibody response against RABV G compared to RABV alone. In order to evaluate the necessity of APRIL for the response to rabies vaccination, we compared the responses of APRIL-deficient and wild-type mice to immunization with rRABV. APRIL deficiency does not affect the primary antibody response to vaccination. Furthermore, APRIL expression by the vaccine did not improve the generation of long-lived antibody-secreting plasma cells (PCs) as serum antibody levels were equivalent in response to rRABV-APRIL and the vector eight weeks after immunization. Moreover, APRIL is dispensable for the long-lived antibody-secreting PC response to rRABV vaccination as anti-RABV G IgG levels were similar in APRIL-deficient and wild-type mice six months after vaccination. Mice lacking the APRIL receptor TACI demonstrated primary anti-RABV G antibody responses similar to wild-type mice following immunization with the vaccine vector indicating that this response is independent of TACI-mediated signals. Collectively, our findings demonstrate that APRIL and associated TACI signaling is dispensable for the immune response to RABV-based vaccination

    Investigating the role for IL-21 in rabies virus vaccine-induced immunity.

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    Over two-thirds of the world\u27s population lives in regions where rabies is endemic, resulting in over 15 million people receiving multi-dose post-exposure prophylaxis (PEP) and over 55,000 deaths per year globally. A major goal in rabies virus (RABV) research is to develop a single-dose PEP that would simplify vaccination protocols, reduce costs associated with RABV prevention, and save lives. Protection against RABV infections requires virus neutralizing antibodies; however, factors influencing the development of protective RABV-specific B cell responses remain to be elucidated. Here we used a mouse model of IL-21 receptor-deficiency (IL-21R-/-) to characterize the role for IL-21 in RABV vaccine-induced immunity. IL-21R-/- mice immunized with a low dose of a live recombinant RABV-based vaccine (rRABV) produced only low levels of primary or secondary anti-RABV antibody response while wild-type mice developed potent anti-RABV antibodies. Furthermore, IL-21R-/- mice immunized with low-dose rRABV were only minimally protected against pathogenic RABV challenge, while all wild-type mice survived challenge, indicating that IL-21R signaling is required for antibody production in response to low-dose RABV-based vaccination. IL-21R-/- mice immunized with a higher dose of vaccine produced suboptimal anti-RABV primary antibody responses, but showed potent secondary antibodies and protection similar to wild-type mice upon challenge with pathogenic RABV, indicating that IL-21 is dispensable for secondary antibody responses to live RABV-based vaccines when a primary response develops. Furthermore, we show that IL-21 is dispensable for the generation of Tfh cells and memory B cells in the draining lymph nodes of immunized mice but is required for the detection of optimal GC B cells or plasma cells in the lymph node or bone marrow, respectively, in a vaccine dose-dependent manner. Collectively, our preliminary data show that IL-21 is critical for the development of optimal vaccine-induced primary but not secondary antibody responses against RABV infections

    Manual for Promoting Agri-environment Measures in Natura 2000 sites in Bulgaria

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