3,449 research outputs found

    Neutrino Decay and Neutrinoless Double Beta Decay in a 3-3-1 Model

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    In this work we show that the implementation of spontaneous breaking of the lepton number in the 3-3-1 model with right-handed neutrinos gives rise to fast neutrino decay with majoron emission and generates a bunch of new contributions to the neutrinoless double beta decay.Comment: Version accepted for publication in the Phys. Rev.

    Comparison of 120Sn(6He,6He)120Sn and 120Sn(alpha,alpha)120Sn elastic scattering and signatures of the 6He neutron halo in the optical potential

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    Cross sections of 120^{120}Sn(α\alpha,α\alpha)120^{120}Sn elastic scattering have been extracted from the α\alpha particle beam contamination of a recent 120^{120}Sn(6^6He,6^6He)120^{120}Sn experiment. Both reactions are analyzed using systematic double folding potentials in the real part and smoothly varying Woods-Saxon potentials in the imaginary part. The potential extracted from the 120^{120}Sn(6^6He,6^6He)120^{120}Sn data may be used as the basis for the construction of a simple global 6^6He optical potential. The comparison of the 6^6He and α\alpha data shows that the halo nature of the 6^6He nucleus leads to a clear signature in the reflexion coefficients ηL\eta_L: the relevant angular momenta LL with ηL0\eta_L \gg 0 and ηL1\eta_L \ll 1 are shifted to larger LL with a broader distribution. This signature is not present in the α\alpha scattering data and can thus be used as a new criterion for the definition of a halo nucleus.Comment: 13 pages, 7 figures, accepted for publication in Phys. Rev.

    Comment on ``Majoron emitting neutrinoless double beta decay in the electroweak chiral gauge extensions''

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    We point out that if the majoron-like scheme is implemented within a 331 model, there must exist at least three different mass scales for the scalar vacuum expectation values in the model.Comment: 4 pages, no figures, Revtex. To be published in Physical Review

    Galactic cold dark matter as a Bose-Einstein condensate of WISPs

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    We propose here the dark matter content of galaxies as a cold bosonic fluid composed of Weakly Interacting Slim Particles (WISPs), represented by spin-0 axion-like particles and spin-1 hidden bosons, thermalized in the Bose-Einstein condensation state and bounded by their self-gravitational potential. We analyze two zero-momentum configurations: the polar phases in which spin alignment of two neighbouring particles is anti-parallel and the ferromagnetic phases in which every particle spin is aligned in the same direction. Using the mean field approximation we derive the Gross-Pitaevskii equations for both cases, and, supposing the dark matter to be a polytropic fluid, we describe the particles density profile as Thomas-Fermi distributions characterized by the halo radii and in terms of the scattering lengths and mass of each particle. By comparing this model with data obtained from 42 spiral galaxies and 19 Low Surface Brightness (LSB) galaxies, we constrain the dark matter particle mass to the range 106104eV10^{-6}-10^{-4} eV and we find the lower bound for the scattering length to be of the order 1014fm10^{-14} fm.Comment: 13 pages; 6 figures; references added; v.3: typo corrected in the abstract, published in JCA

    DISPLASIA FIBROMUSCULAR DA CIRCULAÇÃO POSTERIOR

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    Mapping quantitative trait loci for performance traits on pig chromosome 6 (SSC6).

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    The objective of this study was to perform QTL mapping associated with performance traits on swine chromosome 6 (SSC6). The F2 population was produced by outcrossing using two native Brazilian breed Piau sires and 18 commercial dams. A total of 617 F2 animals were genotyped for 13 microsatellite markers. The traits evaluated in the F2 population were teat number (TN), birth weight (BW), weight at 21, 42, 63, 77 and 105 days of age (W21, W42, W63, W77, W105), weight at slaughter (WS), and average daily gain (ADG), feed intake (FI) and feed/gain ratio (FG) from 77 to 105 days of age. Data were analyzed by multiple regression developed for analysis of crosses between outbred lines, using the QTL Express software. A significant QTL was detected for FI at 99 cM. A suggestive QTL was detected for W42 located at 55 cM. A locus located at 100 cM seems to affect the traits FI and ADG. Evidence for loci affecting weight at the other ages not was not found. O objetivo deste estudo foi obter o mapeamento de QTL no cromossomo 6 suíno (SSC6) associado a características de desempenho. A população F2 foi produzida utilizando o cruzamento divergente de dois reprodutores da raça nativa brasileira Piau e 18 fêmeas comerciais. Um total de 617 animais F2 foram genotipados para 13 marcadores microssatélites. As características avaliadas na população F2 foram: número de tetas (TN), peso ao nascimento (BW), peso aos 21, 42, 63, 77 e 105 dias de idade (W21, W42, W63, W77, W105), peso ao abate (WS), e ganho de peso médio diário (ADG), consumo de ração (FI) e conversão alimentar (FG) dos 77 aos 105 dias de idade. Os dados foram analisados usando a metodologia de regressão múltipla desenvolvida para análises de cruzamentos entre linhas divergentes, usando o software QTL Express. Um QTL significativo foi detectado para FI em 99 cM. Um QTL sugestivo foi detectado para W42 localizado em 55cM. As características FI e ADG parecem estar sob a influência de um loco situado em torno de 100 cM no cromossomo estudado. Não foram encontrados QTLs para peso em as outras diferentes idades

    De Novo HIV Infection Diagnoses in a Department of Dermatology and Venereology in Lisbon, Portugal

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    BACKGROUND: Portugal has the highest prevalence rate of HIV infection in Western Europe. The proportion of patients with a late diagnosis, carried out in full-blown AIDS stage, remains high. Skin and mucous membrane manifestations are not rare in these patients. OBJECTIVE: A demographic, clinical, and laboratorial characterization of patients with de novo HIV infection diagnosis made in the Department of Dermatology and Venereology of a central hospital in Lisbon, Portugal. METHODS: Retrospective review of medical records of adult patients newly diagnosed with HIV infection (reactive immunoassay for antibodies to HIV-1/HIV-2 or HIV p24 antigen) in the Dermatology and Venereology Department of a Portuguese central hospital in the period between January 2005 and December 2013. RESULTS: During the study period, 97 new cases were diagnosed, 70 men and 27 women. The median age at diagnosis was 36 years. Of the total, 50 cases were diagnosed with a concomitant sexually transmitted infection (STI), more frequently syphilis and ano-genital HPV infection. The remaining 47 patients were diagnosed with other dermatological conditions such as prurigo nodularis, psoriasis, and Kaposi's sarcoma. The duration of complaints that lead to medical attention ranged from <1 week to 8 years, being significantly lower in patients diagnosed with a concomitant STI (p < 0.01). Basal viral load was also lower in this group of patients (p < 0.05). Of all the new diagnosed cases, 80% of patients are currently retained in care. CONCLUSION: This study grants a descriptive overview of de novo HIV infection diagnoses performed by dermatovenereologists in a central hospital in Lisbon, Portugal. As in the past, the importance of Dermato-Venereology for HIV infection diagnosis remains present in daily clinical practice

    Scalar resonances in leptophilic multi-Higgs models

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    We show that the Higgs resonance can be amplified in a 3-3-1 model with a multi-Higgs "leptophilic" scalar sector. This would allow the observation of the Higgs particle in muon colliders even for Higgs masses considerably higher than the ones expected to be seen in the electroweak standard model framework.Comment: REVTEX, 18 pages total, contain 5 eps figures and 1 tabl

    Minimal 3-3-1 model, lepton mixing and muonium-antimuonium conversion

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    The recent experimental results on neutrino oscillation and on muonium-antimuonium conversion require extension of the minimal 3-3-1 model. We review the constraints imposed to the model by those measurements and suggest a pattern of leptonic mixing, with charged leptons in a non-diagonal basis, which accounts for the neutrino physics and circumvents the tight muonium-antimuonium bounds on the model. We also illustrate a scenario where this pattern could be realized.Comment: 4 pages; abbreviated version, conclusions unchange

    Estabelecimento de espécies arbóreas de cerrados em função do manejo de Brachiaria sp.

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    Neste estudo teve-se como objetivo avaliar a emergência, o recrutamento e crescimento de sete leguminosas arbóreas dos Cerrados em áreas de pastagem abandonadas, a partir de semeadura direta, sob diferentes regimes de manejo de Brachiaria sp.bitstream/CNPGC-2010/13222/1/COT118.pd
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