1,108 research outputs found

    The electric dipole response of 76^{76}Se above 4 MeV

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    The dipole response of 3476^{76}_{34}Se in the energy range 4 to 9 MeV has been analyzed using a (γ⃗,γ′)(\vec\gamma,{\gamma}') polarized photon scattering technique, performed at the High Intensity γ\gamma-Ray Source facility, to complement previous work performed using unpolarized photons. The results of this work offer both an enhanced sensitivity scan of the dipole response and an unambiguous determination of the parities of the observed J=1 states. The dipole response is found to be dominated by E1E1 excitations, and can reasonably be attributed to a pygmy dipole resonance. Evidence is presented to suggest that a significant amount of directly unobserved excitation strength is present in the region, due to unobserved branching transitions in the decays of resonantly excited states. The dipole response of the region is underestimated when considering only ground state decay branches. We investigate the electric dipole response theoretically, performing calculations in a 3D cartesian-basis time-dependent Skyrme-Hartree-Fock framework.Comment: 20 pages, 18 figures, to be submitted to PR

    Interethnic diversity of NAT2 polymorphisms in Brazilian admixed populations

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    <p>Abstract</p> <p>Background</p> <p>N-acetyltransferase type 2 (Nat2) is a phase II drug- metabolizing enzyme that plays a key role in the bioactivation of aromatic and heterocyclic amines. Its relevance in drug metabolism and disease susceptibility remains a central theme for pharmacogenetic research, mainly because of its genetic variability among human populations. In fact, the evolutionary and ethnic-specific SNPs on the <it>NAT2 </it>gene remain a focus for the potential discoveries in personalized drug therapy and genetic markers of diseases. Despite the wide characterization of <it>NAT2 </it>SNPs frequency in established ethnic groups, little data are available for highly admixed populations. In this context, five common <it>NAT2 </it>SNPs (<it>G191A</it>, <it>C481T</it>, <it>G590A</it>, <it>A803G </it>and G<it>857A</it>) were investigated in a highly admixed population comprised of Afro-Brazilians, Whites, and Amerindians in northeastern Brazil. Thus, we sought to determine whether the distribution of <it>NAT2 </it>polymorphism is different among these three ethnic groups.</p> <p>Results</p> <p>Overall, there were no statistically significant differences in the distribution of <it>NAT2 </it>polymorphism when Afro-Brazilian and White groups were compared. Even the allele frequency of <it>191A</it>, relatively common in African descendents, was not different between the Afro-Brazilian and White groups. However, allele and genotype frequencies of <it>G590A </it>were significantly higher in the Amerindian group than either in the Afro-Brazilian or White groups. Interestingly, a haplotype block between <it>G590A </it>and <it>A803G </it>was verified exclusively among Amerindians.</p> <p>Conclusions</p> <p>Our results indicate that ethnic admixture might contribute to a particular pattern of genetic diversity in the <it>NAT2 </it>gene and also offer new insights for the investigation of possible new <it>NAT2 </it>gene-environment effects in admixed populations.</p

    Ethnicity and attitudes to deceased kidney donation: a survey in Barbados and comparison with Black Caribbean people in the United Kingdom

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    <p>Abstract</p> <p>Background</p> <p>Black minority ethnic groups in the UK have relatively low rates of deceased donation and report a higher prevalence of beliefs that are regarded as barriers to donation. However there is little data from migrants' countries of origin. This paper examines community attitudes to deceased kidney donation in Barbados and compares the findings with a survey conducted in a disadvantaged multi-ethnic area of south London.</p> <p>Methods</p> <p>Questionnaires were administered at four public health centres in Barbados and at three private general practices. Adjusted odds ratios were calculated to compare attitudinal responses with a prior survey of 328 Caribbean and 808 White respondents in south London.</p> <p>Results</p> <p>Questionnaires were completed by 327 respondents in Barbados (93% response); 42% men and 58% women, with a mean age of 40.4 years (SD 12.6). The main religious groups were Anglican (29%) and Pentecostal (24%). Educational levels ranged from 18% not completing 5th form to 12% with university education. Attitudes to the notion of organ donation were favourable, with 73% willing to donate their kidneys after their death and only 5% definitely against this. Most preferred an opt-in system of donation. Responses to nine attitudinal questions identified 18% as having no concerns and 9% as having 4 or more concerns. The highest level of concern (43%) was for lack of confidence that medical teams would try as hard to save the life of a person who has agreed to donate organs. There was no significant association between age, gender, education or religion and attitudinal barriers, but greater knowledge of donation had some positive effect on attitudes. Comparison of attitudes to donation in south London and Barbados (adjusting for gender, age, level of education, employment status) indicated that a significantly higher proportion of the south London Caribbean respondents identified attitudinal barriers to donation.</p> <p>Conclusions</p> <p>Community attitudes in Barbados are favourable to deceased donation based on a system of informed consent. Comparison with south London data supports the hypothesis that the relatively high prevalence of negative attitudes to deceased donation among disadvantaged ethnic minorities in high income countries may reflect feelings of marginalisation and lack of belonging.</p

    Gross-Neveu Models, Nonlinear Dirac Equations, Surfaces and Strings

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    Recent studies of the thermodynamic phase diagrams of the Gross-Neveu model (GN2), and its chiral cousin, the NJL2 model, have shown that there are phases with inhomogeneous crystalline condensates. These (static) condensates can be found analytically because the relevant Hartree-Fock and gap equations can be reduced to the nonlinear Schr\"odinger equation, whose deformations are governed by the mKdV and AKNS integrable hierarchies, respectively. Recently, Thies et al have shown that time-dependent Hartree-Fock solutions describing baryon scattering in the massless GN2 model satisfy the Sinh-Gordon equation, and can be mapped directly to classical string solutions in AdS3. Here we propose a geometric perspective for this result, based on the generalized Weierstrass spinor representation for the embedding of 2d surfaces into 3d spaces, which explains why these well-known integrable systems underlie these various Gross-Neveu gap equations, and why there should be a connection to classical string theory solutions. This geometric viewpoint may be useful for higher dimensional models, where the relevant integrable hierarchies include the Davey-Stewartson and Novikov-Veselov systems.Comment: 27 pages, 1 figur

    The Demographic and Socioeconomic Factors Predictive for Populations at High-Risk for La Crosse Virus Infection in West Virginia

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    Although a large body of literature exists for the environmental risk factors for La Crosse virus (LACV) transmission, the demographic and socioeconomic risk factors for developing LACV infection have not been investigated. Therefore, this study investigated the demographic and socioeconomic risk factors for LACV infection in West Virginia from 2003 to 2007, using two forward stepwise discriminant analyses. The discriminant analyses were used to evaluate a number of demographic and socioeconomic factors for their ability to predict: 1) those census tracts with at least one reported case of LACV infection versus those census tracts with no reported cases of LACV infection and 2) to evaluate significantly high-risk clusters for LACV infection versus significantly low-risk clusters for LACV infection. In the first model, a high school education diploma or a general education diploma or less and a lower housing densit

    Association study in the 5q31-32 linkage region for schizophrenia using pooled DNA genotyping

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    <p>Abstract</p> <p>Background</p> <p>Several linkage studies suggest that chromosome 5q31-32 might contain risk loci for schizophrenia (SZ). We wanted to identify susceptibility genes for schizophrenia within this region.</p> <p>Methods</p> <p>We saturated the interval between markers D5S666 and D5S436 with 90 polymorphic microsatellite markers and genotyped two sets of DNA pools consisting of 300 SZ patients of Bulgarian origin and their 600 parents. Positive associations were followed-up with SNP genotyping.</p> <p>Results</p> <p>Nominally significant evidence for association (p < 0.05) was found for seven markers (D5S0023i, IL9, RH60252, 5Q3133_33, D5S2017, D5S1481, D5S0711i) which were then individually genotyped in the trios. The predicted associations were confirmed for two of the markers: D5S2017, localised in the <it>SPRY4-FGF1 </it>locus (p = 0.004) and IL9, localized within the IL9 gene (p = 0.014). Fine mapping was performed using single nucleotide polymorphisms (SNPs) around D5S2017 and IL9. In each region four SNPs were chosen and individually genotyped in our full sample of 615 SZ trios. Two SNPs showed significant evidence for association: rs7715300 (p = 0.001) and rs6897690 (p = 0.032). Rs7715300 is localised between the <it>TGFBI </it>and <it>SMAD5 </it>genes and rs6897690 is within the <it>SPRY4 </it>gene.</p> <p>Conclusion</p> <p>Our screening of 5q31-32 implicates three potential candidate genes for SZ: <it>SMAD5</it>, <it>TGFBI </it>and <it>SPRY4</it>.</p

    Search for CP violation in D+→ϕπ+ and D+s→K0Sπ+ decays

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    A search for CP violation in D + → ϕπ + decays is performed using data collected in 2011 by the LHCb experiment corresponding to an integrated luminosity of 1.0 fb−1 at a centre of mass energy of 7 TeV. The CP -violating asymmetry is measured to be (−0.04 ± 0.14 ± 0.14)% for candidates with K − K + mass within 20 MeV/c 2 of the ϕ meson mass. A search for a CP -violating asymmetry that varies across the ϕ mass region of the D + → K − K + π + Dalitz plot is also performed, and no evidence for CP violation is found. In addition, the CP asymmetry in the D+s→K0Sπ+ decay is measured to be (0.61 ± 0.83 ± 0.14)%
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