5,614 research outputs found

    Music matters: Preattentive musicality of the human brain

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    During listening to a musical piece, unexpected harmonies may evoke brain responses that are reflected electrically as an early right anterior negativity (ERAN) and a late frontal negativity (N5). In the present study we demonstrate that these components of the event-related potential can be evoked preattentively, that is, even when a musical stimulus is ignored. Both ERAN and N5 differed in amplitude as a function of music-theoretical principles. Participants had no special musical expertise; results thus provide evidence for an automatic processing of musical information in onmusicians.

    Genome Structure And Emerging Evidence Of An Incipient Sex Chromosome In Populus

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    The genus Populus consists of dioecious woody species with largely unknown genetic mechanisms for gender determination. We have discovered genetic and genomic features in the peritelomeric region of chromosome XIX that suggest this region of the Populus genome is in the process of developing characteristics of a sex chromosome. We have identified a gender-associated locus that consistently maps to this region. Furthermore, comparison of genetic maps across multiple Populus families reveals consistently distorted segregation within this region. We have intensively characterized this region using an F1 interspecific cross involving the female genotype that was used for genome sequencing. This region shows suppressed recombination and high divergence between the alternate haplotypes, as revealed by dense map-based genome assembly using microsatellite markers. The suppressed recombination, distorted segregation, and haplotype divergence were observed only for the maternal parent in this cross. Furthermore, the progeny of this cross showed a strongly male-biased sex ratio, in agreement with Haldane’s rule that postulates that the heterogametic sex is more likely to be absent, rare, or sterile in interspecific crosses. Together, these results support the role of chromosome XIX in sex determination and suggest that sex determination in Populus occurs through a ZW system in which the female is the heterogametic gender

    Asymptotic quasinormal modes of Reissner-Nordstr\"om and Kerr black holes

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    According to a recent proposal, the so-called Barbero-Immirzi parameter of Loop Quantum Gravity can be fixed, using Bohr's correspondence principle, from a knowledge of highly-damped black hole oscillation frequencies. Such frequencies are rather difficult to compute, even for Schwarzschild black holes. However, it is now quite likely that they may provide a fundamental link between classical general relativity and quantum theories of gravity. Here we carry out the first numerical computation of very highly damped quasinormal modes (QNM's) for charged and rotating black holes. In the Reissner-Nordstr\"om case QNM frequencies and damping times show an oscillatory behaviour as a function of charge. The oscillations become faster as the mode order increases. At fixed mode order, QNM's describe spirals in the complex plane as the charge is increased, tending towards a well defined limit as the hole becomes extremal. Kerr QNM's have a similar oscillatory behaviour when the angular index m=0m=0. For l=m=2l=m=2 the real part of Kerr QNM frequencies tends to 2Ω2\Omega, Ω\Omega being the angular velocity of the black hole horizon, while the asymptotic spacing of the imaginary parts is given by 2πTH2\pi T_H.Comment: 13 pages, 7 figures. Added result on the asymptotic spacing of the imaginary part, minor typos correcte

    Why spontaneous symmetry breaking disappears in a bridge system with PDE-friendly boundaries

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    We consider a driven diffusive system with two types of particles, A and B, coupled at the ends to reservoirs with fixed particle densities. To define stochastic dynamics that correspond to boundary reservoirs we introduce projection measures. The stationary state is shown to be approached dynamically through an infinite reflection of shocks from the boundaries. We argue that spontaneous symmetry breaking observed in similar systems is due to placing effective impurities at the boundaries and therefore does not occur in our system. Monte-Carlo simulations confirm our results.Comment: 24 pages, 7 figure

    Estrogen and progesterone-related gene variants and colorectal cancer risk in women

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    <p>Abstract</p> <p>Background</p> <p>Observational studies and randomized trials have suggested that estrogens and/or progesterone may lower the risk for colorectal cancer. Inherited variation in the sex-hormone genes may be one mechanism by which sex hormones affect colorectal cancer, although data are limited.</p> <p>Method</p> <p>We conducted a comprehensive evaluation of single nucleotide polymorphisms (SNPs) in genes encoding 3 hormone receptors (<it>ESR1, ESR2, PGR</it>) and 5 hormone synthesizers (<it>CYP19A1 and CYP17A1, HSD17B1, HSD17B2, HSD17B4</it>) among 427 women with incident colorectal cancer and 871 matched controls who were Caucasians of European ancestry from 93676 postmenopausal women enrolled in the Women's Health Initiative Observational cohort. A total of 242 haplotype-tagging and functional SNPs in the 8 genes were included for analysis. Unconditional logistic regression with adjustment for age and hysterectomy status was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs).</p> <p>Results</p> <p>We observed a weak association between the <it>CYP17A1 </it>rs17724534 SNP and colorectal cancer risk (OR per risk allele (A) = 1.39, 95% CI = 1.09-1.78, corrected p-value = 0.07). In addition, a suggestive interaction between rs17724534 and rs10883782 in 2 discrete LD blocks of <it>CYP17A1 </it>was observed in relation to colorectal cancer (empirical p value = 0.04). Moreover, one haplotype block of <it>CYP19A1 </it>was associated with colorectal cancer (corrected global p value = 0.02), which likely reflected the association with the tagging SNP, rs1902584, in the block.</p> <p>Conclusion</p> <p>Our findings offer some support for a suggestive association of <it>CYP17A1 </it>and <it>CYP19A1 </it>variants with colorectal cancer risk.</p

    Doing gender locally: The importance of ‘place’ in understanding marginalised masculinities and young men’s transitions to ‘safe’ and successful futures

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    Observable anxieties have been developing about the position of boys and young men in contemporary society in recent years. This is expressed as a crisis of masculinity, in which place is often implicitly implicated, but is rarely considered for its role in the shaping of young men’s practices, trajectories and aspirations. Drawing on research conducted with young people who accessed a range of social care support services, this article argues that transition means different things for young men in different locales and that local definitions of masculinity are required to better understand young men’s lives and the opportunities available to them. The authors argue that home life, street life, individual neighbourhoods, regions and nations all shaped the young men’s identities and the practices they (and the staff working with them) drew on in order to create successful futures and ‘safe’ forms of masculinity. It is suggested that this place-based approach has the potential to re-shape the ‘crisis’ discourse surrounding masculinity and the anxieties associated with young men

    A Study of the \eta \pi^{0} Spectrum and Search for a J^{PC} = 1^{-+} Exotic Meson

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    A partial wave analysis (PWA) of the of the ηπ0\eta \pi ^0 system (where ηγγ\eta \to \gamma \gamma) produced in the charge exchange reaction πpηπ0n\pi ^-p\to \eta \pi ^0n at an incident momentum of 18 GeV/c/c is presented as a function of ηπ0{\eta \pi ^0} invariant mass, mηπ0m_{\eta\pi^0}, and momentum transfer squared, tπηπt_{\pi^{-}\to\eta\pi}, from the incident π\pi^- to the outgoing ηπ0{\eta\pi ^0} system. SS, PP and DD waves were included in the PWA. The a0(980)a_0(980) and a2(1320)a_2(1320) states are clearly observed in the overall ηπ0{\eta\pi ^0} effective mass distribution as well as in the amplitudes associated with SS wave and DD waves respectively after partial wave decomposition. The observed distributions in moments (averages of spherical harmonics) were compared to the results from the PWA and the two are consistent. The distribution in tπηπt_{\pi^{-}\to\eta\pi} for individual DD waves associated with natural and unnatural parity exchange in the tt-channel are consistent with Regge phenomenology. Of particular interest in this study is the PP wave since this leads to an exotic JPC=1+J^{PC}=1^{-+} for the ηπ\eta \pi system. A PP wave is present in the data, however attempts to describe the mass dependence of the amplitude and phase motion with respect to the DD wave as a Breit-Wigner resonance are problematic. This has implications regarding the existence of a reported exotic JPC=1+J^{PC} = 1^{-+} meson decaying into ηπ0\eta \pi^0 with a mass near 1.4 GeV/c2/c^2.Comment: 19 pages, 29 figures, to appear in Phys. Rev.
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