79 research outputs found

    Vanishing of algebraic Brauer-Manin obstructions

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    Components of Antineutrino Emission in Nuclear Reactor

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    New νˉe,e{\bar{\nu}_e},e scattering experiments aimed for sensitive searches of the νe{\nu}_e magnetic moment and projects to explore small mixing angle oscillations at reactors call for a better understanding of the reactor antineutrino spectrum. Here we consider six components, which contribute to the total νˉe{\bar{\nu}_e} spectrum generated in nuclear reactor. They are: beta decay of the fission fragments of 235^{235}U, 239^{239}Pu, 238^{238}U and 241^{241}Pu, decay of beta-emitters produced as a result of neutron capture in 238^{238}U and also due to neutron capture in accumulated fission fragments which perturbs the spectrum. For antineutrino energies less than 3.5 MeV we tabulate evolution of νˉe{\bar{\nu}_e} spectra corresponding to each of the four fissile isotopes vs fuel irradiation time and their decay after the irradiation is stopped and also estimate relevant uncertainties. Small corrections to the ILL spectra are considered.Comment: LaTex 8 pages, 2 ps figure

    Galois sections for abelianized fundamental groups

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    Given a smooth projective curve XX of genus at least 2 over a number field kk, Grothendieck's Section Conjecture predicts that the canonical projection from the \'etale fundamental group of XX onto the absolute Galois group of kk has a section if and only if the curve has a rational point. We show that there exist curves where the above map has a section over each completion of kk but not over kk. In the appendix Victor Flynn gives explicit examples in genus 2. Our result is a consequence of a more general investigation of the existence of sections for the projection of the \'etale fundamental group `with abelianized geometric part' onto the Galois group. We give a criterion for the existence of sections in arbitrary dimension and over arbitrary perfect fields, and then study the case of curves over local and global fields more closely. We also point out the relation to the elementary obstruction of Colliot-Th\'el\`ene and Sansuc.Comment: This is the published version, except for a characteristic 0 assumption added in Section 5 which was unfortunately omitted there. Thanks to O. Wittenberg for noticing i

    Disgust sensitivity relates to attitudes toward gay men and lesbian women across 31 nations

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    Previous work has reported a relation between pathogen-avoidance motivations and prejudice toward various social groups, including gay men and lesbian women. It is currently unknown whether this association is present across cultures, or specific to North America. Analyses of survey data from adult heterosexuals ( N = 11,200) from 31 countries showed a small relation between pathogen disgust sensitivity (an individual-difference measure of pathogen-avoidance motivations) and measures of antigay attitudes. Analyses also showed that pathogen disgust sensitivity relates not only to antipathy toward gay men and lesbians, but also to negativity toward other groups, in particular those associated with violations of traditional sexual norms (e.g., prostitutes). These results suggest that the association between pathogen-avoidance motivations and antigay attitudes is relatively stable across cultures and is a manifestation of a more general relation between pathogen-avoidance motivations and prejudice towards groups associated with sexual norm violations
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