1,263 research outputs found

    Primary familial congenital erythrocytosis: two novel EPOR mutations found in Spain

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    Two-carbon ring expansions of vinyl β-lactones, were carried out by Lewis acids (BF3-Et2O or Et2AlCl) via an ionization/cation rearrangement. β,γ-unsaturated δ-lactones were produced as efficient protocols for the synthesis of bioactive substances. Vinyl β-lactones were prepared via ring closure of corresponding unsaturated β-hydroxy acids. Differently structured substrates were examined to study the influence of the substituents on the rearrangement. Other factors, such as temperature, solvent and catalyst were also studied in search of suitable reaction conditions. This method is moderately successful in providing fused-ring δ-lactones, but higher yields (so far total yield of 24.8%) and a better method for the separation of β- and δ-lactones are required for useful synthetic applications. The successful implementation of this conceptually novel strategy will provide a versatile and expedient route for the synthesis of δ-lactones bearing a wide range of substitution patterns

    Instabilities in neutrino-plasma density waves

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    One examines the interaction and possible resonances between supernova neutrinos and electron plasma waves. The neutrino phase space distribution and its boundary regions are analyzed in detail. It is shown that the boundary regions are too wide to produce non-linear resonant effects. The growth or damping rates induced by neutrinos are always proportional to the neutrino flux and GF2G_{{\rm F}}^{2}.Comment: 9 pages, a few words modified to match PRD publicatio

    WMAP Bounds on Braneworld Tachyonic Inflation

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    We analyse the implications of the Wilkinson Microwave Anisotropy Probe (WMAP) results for a braneworld tachyonic model of inflation. We find that WMAP bounds on nsn_s allow us to constrain significantly the parameter space of the model; in particular, extremely weak string coupling is required, gs1015g_s \sim 10^{-15}. Moreover, our analysis shows that the running of the scalar spectral index is within the bounds determined by WMAP for the allowed range of model parameters; however, it is not possible to obtain ns>1n_s>1 on large scales and ns<1n_s<1 on small scales.Comment: 15 pages, 2 eps figure

    Inclusive dileptonic rare B decays with an extra generation of vector-like quarks

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    We investigate the leading effects of extending the Standard Model of electroweak interactions by an extra iso-singlet up- and down- type quark pair on various distributions and total branching ratio of the inclusive B-> X_s l^+ l^- (l =e,\mu) rare B decays. The presence of the extra vector-like down quark DD results in the non-unitarity of the extended quark mixing matrix V, which in turn leads to b-> s FCNC at the tree level proportional to (V^\dagger V)_{sb}. On the other hand, the effective penguin and box vertex functions are sensitive to the mass of the extra iso-singlet up quark m_U. The experimental upper bound on BR(B-> X_s \mu^+ \mu^-) is used to constrain the parameters of the model. It is shown that the shapes of the differential branching ratio and forward-backward asymmetry distribution are very sensitive to the value of the model parameters. We also calculate the CP aymmetry distribution of the dileptonic decay in the vector-like quark model. It is shown that, for a typical choice of the model parameters, asymmetries up to around 10% can be achieved for certain values of the dilepton invariant mass.Comment: 15 pages, 2 figure

    The ν\nu-cleus experiment: A gram-scale fiducial-volume cryogenic detector for the first detection of coherent neutrino-nucleus scattering

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    We discuss a small-scale experiment, called ν\nu-cleus, for the first detection of coherent neutrino-nucleus scattering by probing nuclear-recoil energies down to the 10 eV-regime. The detector consists of low-threshold CaWO4_4 and Al2_2O3_3 calorimeter arrays with a total mass of about 10 g and several cryogenic veto detectors operated at millikelvin temperatures. Realizing a fiducial volume and a multi-element target, the detector enables active discrimination of γ\gamma, neutron and surface backgrounds. A first prototype Al2_2O3_3 device, operated above ground in a setup without shielding, has achieved an energy threshold of 20{\sim20} eV and further improvements are in reach. A sensitivity study for the detection of coherent neutrino scattering at nuclear power plants shows a unique discovery potential (5σ\sigma) within a measuring time of 2{\lesssim2} weeks. Furthermore, a site at a thermal research reactor and the use of a radioactive neutrino source are investigated. With this technology, real-time monitoring of nuclear power plants is feasible.Comment: 14 pages, 19 figure

    Real CP violation in a simple extension of the standard model

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    I present a simple three-Higgs-doublet extension of the standard model in which real CP violation takes place. The strong CP problem is attenuated by this model.Comment: 8 page

    D0Dˉ0D^0 - \bar D^0 Mixing in the Presence of Isosinglet Quarks

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    We analyse ΔC=2\Delta C=2 transitions in the framework of a minimal extension of the Standard Model where either a Q=2/3Q=2/3 or a Q=1/3Q=-1/3 isosinglet quark is added to the standard quark spectrum. In the case of a Q=2/3Q=2/3 isosinglet quark, it is shown that there is a significant region of parameter space where D0Dˉ0D^0 - \bar D^0 mixing is sufficiently enhanced to be observed at the next round of experiments. On the contrary, in the case of a Q=1/3Q=-1/3 isosinglet quark, it is pointed out that obtaining a substancial enhancement of D0Dˉ0D^0 - \bar D^0 mixing, while complying with the experimental constraints on rare kaon decays, requires a contrived choice of parameters.Comment: 10 pages plus four figures. The figures are not included but are available upon reques

    Crosstalk between cilia and autophagy: implication for human diseases

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    Macroautophagy/autophagy is a self-degradative process necessary for cells to maintain their energy balance during development and in response to nutrient deprivation. Autophagic processes are tightly regulated and have been found to be dysfunctional in several pathologies. Increasing experimental evidence points to the existence of an interplay between autophagy and cilia. Cilia are microtubule-based organelles protruding from the cell surface of mammalian cells that perform a variety of motile and sensory functions and, when dysfunctional, result in disorders known as ciliopathies. Indeed, selective autophagic degradation of ciliary proteins has been shown to control ciliogenesis and, conversely, cilia have been reported to control autophagy. Moreover, a growing number of players such as lysosomal and mitochondrial proteins are emerging as actors of the cilia-autophagy interplay. However, some of the published data on the cilia-autophagy axis are contradictory and indicate that we are just starting to understand the underlying molecular mechanisms. In this review, the current knowledge about this axis and challenges are discussed, as well as the implication for ciliopathies and autophagy-associated disorders

    The generalized second law for the interacting generalized Chaplygin gas model

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    We investigate the validity of the generalized second law (GSL) of gravitational thermodynamics in a non-flat FRW universe containing the interacting generalized Chaplygin gas with the baryonic matter. The dynamical apparent horizon is assumed to be the boundary of the universe. We show that for the interacting generalized Chaplygin gas as a unified candidate for dark matter (DM) and dark energy (DE), the equation of state parameter can cross the phantom divide. We also present that for the selected model under thermal equilibrium with the Hawking radiation, the GSL is always satisfied throughout the history of the universe for any spatial curvature, independently of the equation of state of the interacting generalized Chaplygin gas model.Comment: 8 page
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