59 research outputs found

    Results of Exploratory Deep-sea Fishing Survey in the Galician Bank: Biological Aspects on Some of Seamount-associated Fish (ICES Division IXb)

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    Since October 1998 to October 1999 an experimental survey, comprising 12 monthly fishing trips were carried out in Galician Bank (ICES Divisions IXb) by two commercial trawlers of the Spanish fleet. The aims of this survey were to explore the fishing resources of studied area and to know the species community associated to this seamount. A total of 297 valid hauls were made during 309 hours of fishing and yielded a total catch of 45 145 kg in the depth strata studied (650-1200 m). The community of species in the area prospected presented high species richness. A total of 106 species were made up of 70 teleosts, 11 sharks, 3 rays, 2 chimaeras, 11 crustacea, 6 molluscs and 3 equinoderms The most important species captured were teleosts: H. mediterraneus, M.moro, L. eques, A. bairdii, E. telescopus, T. cristulata and L. piscatorius, followed for deep sharks: D. licha, D. calceus and crustacean: Ch affinis. The yields obtained for the whole series of fishing trips were low being the values obtained by order of importance: 30.3, 14.0, 13.1, 11.7, 4.8, 4.2, 2.5 kg/h and 1 kg/h for the teleosts; 2.0, 1.7, kg/h for sharks and 1.2 kg/h for crustacean. The results indicate, in general, there were no differences in depth distribution of the species characterised by the presence or absence of certain species and also, a seasonal variation in the abundance of the most important caught

    High scale mixing unification and large neutrino mixing angles

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    Starting with the hypothesis that quark and lepton mixings are identical at or near the GUT scale, we show that the large solar and atmospheric neutrino mixing angles together with the small reactor angle Ue3U_{e3} can be understood purely as a result of renormalization group evolution. The only requirements are that the three neutrinos must be quasi degenerate in mass and have same CP parity. It predicts that the common Majorana mass for the neutrinos must be larger than 0.1 eV making the idea testable in the currently planned or ongoing experiments searching for neutrinoless-double-beta decay.Comment: 10 pages, eight figure, two tables; new material added; results remain unchange

    Phenomenological Tests of Supersymmetric A_4 Family Symmetry Model of Neutrino Mass

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    Recently Babu, Ma and Valle proposed a model of quark and lepton mixing based on A4A_4 symmetry. Within this model the lepton and slepton mixings are intimately related. We perform a numerical study in order to derive the slepton masses and mixings in agreement with present data from neutrino physics. We show that, starting from three-fold degeneracy of the neutrino masses at a high energy scale, a viable low energy neutrino mass matrix can indeed be obtained in agreement with constraints on lepton flavour violating μ\mu and τ\tau decays. The resulting slepton spectrum must necessarily include at least one mass below 200 GeV which can be produced at the LHC. The predictions for the absolute Majorana neutrino mass scale m00.3m_0 \geq 0.3 eV ensure that the model will be tested by future cosmological tests and ββ0ν\beta\beta_{0\nu} searches. Rates for lepton flavour violating processes ji+γ\ell_j \to \ell_i + \gamma in the range of sensitivity of current experiments are typical in the model, with BR(\mu \to e \gamma) \gsim 10^{-15} and the lower bound BR(τμγ)>109(\tau \to \mu \gamma) > 10^{-9}. To first approximation, the model leads to maximal leptonic CP violation in neutrino oscillations.Comment: 23 pages, 7 figure

    Radiative Corrections to Neutrino Mixing and CP Violation in the Minimal Seesaw Model with Leptogenesis

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    Radiative corrections to neutrino mixing and CP violation are analyzed in the minimal seesaw model with two heavy right-handed neutrinos. We find that textures of the effective Majorana neutrino mass matrix are essentially stable against renormalization effects. Taking account of the Frampton-Glashow-Yanagida ansatz for the Dirac neutrino Yukawa coupling matrix, we calculate the running effects of light neutrino masses, lepton flavor mixing angles and CP-violating phases for both m1=0m_1 =0 (normal mass hierarchy) and m3=0m_3 =0 (inverted mass hierarchy) cases in the standard model and in its minimal supersymmetric extension. Very instructive predictions for the cosmological baryon number asymmetry via thermal leptogenesis are also given with the help of low-energy neutrino mixing quantities.Comment: 21 pages, 6 figures; more references adde

    Neutrino Masses, Mixing and New Physics Effects

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    We introduce a parametrization of the effects of radiative corrections from new physics on the charged lepton and neutrino mass matrices, studying how several relevant quantities describing the pattern of neutrino masses and mixing are affected by these corrections. We find that the ratio omega = sin theta / tan theta_atm is remarkably stable, even when relatively large corrections are added to the original mass matrices. It is also found that if the lightest neutrino has a mass around 0.3 eV, the pattern of masses and mixings is considerably more stable under perturbations than for a lighter or heavier spectrum. We explore the consequences of perturbations on some flavor relations given in the literature. In addition, for a quasi-degenerate neutrino spectrum it is shown that: (i) starting from a bi-maximal mixing scenario, the corrections to the mass matrices keep tan theta_atm very close to unity while they can lower tan theta_sol to its measured value; (ii) beginning from a scenario with a vanishing Dirac phase, corrections can induce a Dirac phase large enough to yield CP violation observable in neutrino oscillations.Comment: 14 pages, 21 figures. Uses RevTeX4. Added several comments and references. Final version to appear in PR

    Exploring flavor structure of supersymmetry breaking from rare B decays and unitarity triangle

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    We study effects of supersymmetric particles in various rare B decay processes as well as in the unitarity triangle analysis. We consider three different supersymmetric models, the minimal supergravity, SU(5) SUSY GUT with right-handed neutrinos, and the minimal supersymmetric standard model with U(2) flavor symmetry. In the SU(5) SUSY GUT with right-handed neutrinos, we consider two cases of the mass matrix of the right-handed neutrinos. We calculate direct and mixing-induced CP asymmetries in the b to s gamma decay and CP asymmetry in B_d to phi K_S as well as the B_s--anti-B_s mixing amplitude for the unitarity triangle analysis in these models. We show that large deviations are possible for the SU(5) SUSY GUT and the U(2) model. The pattern and correlations of deviations from the standard model will be useful to discriminate the different SUSY models in future B experiments.Comment: revtex4, 36 pages, 10 figure

    Cross-ancestry genome-wide association analysis of corneal thickness strengthens link between complex and Mendelian eye diseases

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    Central corneal thickness (CCT) is a highly heritable trait associated with complex eye diseases such as keratoconus and glaucoma. We perform a genome-wide association meta-analysis of CCT and identify 19 novel regions. In addition to adding support for known connective tissue-related pathways, pathway analyses uncover previously unreported gene sets. Remarkably, >20% of the CCT-loci are near or within Mendelian disorder genes. These included FBN1, ADAMTS2 and TGFB2 which associate with connective tissue disorders (Marfan, Ehlers-Danlos and Loeys-Dietz syndromes), and the LUM-DCN-KERA gene complex involved in myopia, corneal dystrophies and cornea plana. Using index CCT-increasing variants, we find a significant inverse correlation in effect sizes between CCT and keratoconus (r =-0.62, P = 5.30 × 10-5) but not between CCT and primary open-angle glaucoma (r =-0.17, P = 0.2). Our findings provide evidence for shared genetic influences between CCT and keratoconus, and implicate candidate genes acting in collagen and extracellular matrix regulation

    Improving Genetic Prediction by Leveraging Genetic Correlations Among Human Diseases and Traits

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    Genomic prediction has the potential to contribute to precision medicine. However, to date, the utility of such predictors is limited due to low accuracy for most traits. Here theory and simulation study are used to demonstrate that widespread pleiotropy among phenotypes can be utilised to improve genomic risk prediction. We show how a genetic predictor can be created as a weighted index that combines published genome-wide association study (GWAS) summary statistics across many different traits. We apply this framework to predict risk of schizophrenia and bipolar disorder in the Psychiatric Genomics consortium data, finding substantial heterogeneity in prediction accuracy increases across cohorts. For six additional phenotypes in the UK Biobank data, we find increases in prediction accuracy ranging from 0.7 for height to 47 for type 2 diabetes, when using a multi-trait predictor that combines published summary statistics from multiple traits, as compared to a predictor based only on one trait. © 2018 The Author(s)

    Geographical and temporal distribution of SARS-CoV-2 clades in the WHO European Region, January to June 2020

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    We show the distribution of SARS-CoV-2 genetic clades over time and between countries and outline potential genomic surveillance objectives. We applied three available genomic nomenclature systems for SARS-CoV-2 to all sequence data from the WHO European Region available during the COVID-19 pandemic until 10 July 2020. We highlight the importance of real-time sequencing and data dissemination in a pandemic situation. We provide a comparison of the nomenclatures and lay a foundation for future European genomic surveillance of SARS-CoV-2.Peer reviewe
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