1,551 research outputs found

    Relating leptogenesis parameters to light neutrino masses

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    We obtain model independent relations among neutrino masses and leptogenesis parameters. We find exact relations that involve the CP asymmetries ϵNα\epsilon_{N_\alpha}, the washout parameters m~α\tilde m_\alpha and θαβ\theta_{\alpha\beta}, and the neutrino masses mim_i and MαM_\alpha, as well as powerful inequalities that involve just m~α\tilde m_\alpha and mim_i. We prove that the Yukawa interactions of at least two of the heavy singlet neutrinos are in the strong washout region (m~α103eV\tilde m_\alpha\gg10^{-3} eV).Comment: 5 pages, 1 figur

    Effect of annealing treatments on the anisotropy of a magnesium alloy sheet processed by severe rolling

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    The effect of annealing treatments on the normal plastic anisotropy (r-value) of a magnesium alloy, AZ61, processed by severe rolling was investigated. The various annealing treatments produce two effects on microstructure: grain coarsening and slight weakening of the texture. In addition, these treatments produce a noticeable decrease of the anisotropy that was correlated with an increase in strain rate sensitivity and a decrease of work hardening rate. It is concluded that an enhanced contribution of basal slip occurs as a consequence of the annealing treatments.The authors acknowledge the financial support from the CICYT grant MAT 2006-02672 awarded by the Spanish Ministry of Education and Science.Peer reviewe

    Study of flavour dependencies in leptogenesis

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    We study the impact of flavours on the efficiency factors and give analytical and numerical results of the baryon asymmetry taking into account the different charged lepton Yukawa contributions and the complete (diagonal and off-diagonal) LL to BLB-L conversion AA matrix. With this treatment we update the lower bound on the lightest right-handed neutrino mass.Comment: 13 pages, 11 figures. typos corrected, some formulae modified. 2 figures and discussion adde

    Structural and magnetic properties of an InGaAs/Fe3_3Si superlattice in cylindrical geometry

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    The structure and the magnetic properties of an InGaAs/Fe3Si superlattice in a cylindrical geometry are investigated by electron microscopy techniques, x-ray diffraction and magnetometry. To form a radial superlattice, a pseudomorphic InGaAs/Fe3As bilayer has been released from its substrate self-forming into a rolled-up microtube. Oxide-free interfaces as well as areas of crystalline bonding are observed and an overall lattice mismatch between succeeding layers is determined. The cylindrical symmetry of the final radial superlattice shows a significant effect on the magnetization behavior of the rolled-up layers

    Fisheries

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    This is the final version. Available from MCCIP via the DOI in this record

    CP violation in scatterings, three body processes and the Boltzmann equations for leptogenesis

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    We obtain the Boltzmann equations for leptogenesis including decay and scattering processes with two and three body initial or final states. We present an explicit computation of the CP violating scattering asymmetries. We analyze their possible impact in leptogenesis, and we discuss the validity of their approximate expressions in terms of the decay asymmetry. In scenarios in which the initial heavy neutrino density vanishes, the inclusion of CP asymmetries in scatterings can enforce a cancellation between the lepton asymmetry generated at early times and the asymmetry produced at later times. We argue that a sizeable amount of washout is crucial for spoiling this cancellation, and we show that in the regimes in which the washouts are particularly weak, the inclusion of CP violation in scatterings yields a reduction in the final value of the lepton asymmetry. In the strong washout regimes the inclusion of CP violation in scatterings still leads to a significant enhancement of the lepton asymmetry at high temperatures; however, due to the independence from the early conditions that is characteristic of these regimes, the final value of the lepton asymmetry remains approximately unchanged.Comment: 24 pages, 6 figures. One appendix added. Some numerical results and corresponding figures (mainly fig. 3) corrected. Final version to be published in JHE

    Окрема думка судді в кримінальному процесі

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    З’ясовується змістове наповнення правових засад, на підставі яких суддя може викласти окрему думку. Досліджується поняття «окремої думки судді» в різних країнах та правових системах. Висвітлюється механізм реалізації окремої думки судді в порівнянні з правом зарубіжних держав та вносить пропозиції щодо запозичення та ведення аналогічних механізмів реалізації окремої думки судді в Україні.Раскрывается содержание правовых принципов, на основании которых судья может изложить особое мнение. Исследуется понятие «особого мнения судьи » в разных странах и правовых системах. Освещается механизм реализации особого мнения судьи в сравнении с правом зарубежных государств и вносит предложение относительно заимствования и ведения аналогичных механизмов реализации особого мнения судьи в Украине.This article investigated the legal principles on which the judge may express the separate opinion; the existence of the notion of «the separate opinion of judge» in different countries and legal systems is conducted. The author analyzed the mechanism of realization of the separate opinion of judge in comparison with the law of foreign countries and made proposals for borrowing and introduction of the similar mechanisms for realization the dissenting the separate opinion of judge in Ukraine

    Development of high-temperature ferromagnetism in SnO2 and paramagnetism in SnO by Fe doping

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    We report the development of room-temperature ferromagnetism in chemically synthesized powder samples of Sn1−xFexO2 (0.005≤ x ≤0.05) and paramagnetic behavior in an identically synthesized set of Sn1−xFexO. The ferromagnetic Sn0.99Fe0.01O2 showed a Curie temperature TC=850 K, which is among the highest reported for transition-metal-doped semiconductor oxides. With increasing Fe doping, the lattice parameters of SnO2 decreased and the saturation magnetization increased, suggesting a strong structure-magnetic property relationship. When the Sn0.95Fe0.05O2 was prepared at different temperatures between 200 and 900 °C, systematic changes in the magnetic properties were observed. Combined Mössbauer spectroscopy and magnetometry measurements showed a ferromagnetic behavior in Sn0.95Fe0.05O2 samples prepared at and above 350°C, but the ferromagnetic component decreased gradually as preparation temperature approached 600 °C. All Sn0.95Fe0.05O2 samples prepared above 600 °C were paramagnetic. X-ray photoelectron spectroscopy, magnetometry, and particle induced x-ray emission studies showed that the Fe dopants diffuse towards the surface of the particles in samples prepared at higher temperatures, gradually destroying the ferromagnetism. Mössbauer studies showed that the magnetically ordered Fe3+ spins observed in the Sn0.95Fe0.05O2 sample prepared at 350 °C is only ~24% of the uniformly incorporated Fe3+. No evidence of any iron oxide impurity phases were detected in Sn1−xFexO2 or Sn1−xFexO, suggesting that the emerging magnetic interactions in these systems are most likely related to the properties of the host systems SnO2 and SnO, and their oxygen stoichiometry

    The Effects of Nutrient Enrichment and Herbivore Abundance on the Ability of Turf Algae to Overgrow Coral in the Caribbean

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    Turf algae are multispecies communities of small marine macrophytes that are becoming a dominant component of coral reef communities around the world. To assess the impact of turf algae on corals, we investigated the effects of increased nutrients (eutrophication) on the interaction between the Caribbean coral Montastraea annularis and turf algae at their growth boundary. We also assessed whether herbivores are capable of reducing the abundance of turf algae at coral-algae boundaries. We found that turf algae cause visible (overgrowth) and invisible negative effects (reduced fitness) on neighbouring corals. Corals can overgrow neighbouring turf algae very slowly (at a rate of 0.12 mm 3 wk−1) at ambient nutrient concentrations, but turf algae overgrew corals (at a rate of 0.34 mm 3 wk−1) when nutrients were experimentally increased. Exclusion of herbivores had no measurable effect on the rate turf algae overgrew corals. We also used PAM fluorometry (a common approach for measuring of a colony's “fitness”) to detect the effects of turf algae on the photophysiology of neighboring corals. Turf algae always reduced the effective photochemical efficiency of neighbouring corals, regardless of nutrient and/or herbivore conditions. The findings that herbivores are not capable of controlling the abundance of turf algae and that nutrient enrichment gives turf algae an overall competitive advantage over corals together have serious implications for the health of Caribbean coral reef systems. At ambient nutrient levels, traditional conservation measures aimed at reversing coral-to-algae phase shifts by reducing algal abundance (i.e., increasing herbivore populations by establishing Marine Protected Areas or tightening fishing regulations) will not necessarily reduce the negative impact of turf algae on local coral communities. Because turf algae have become the most abundant benthic group on Curaçao (and likely elsewhere in the Caribbean), new conservation strategies are required to mitigate their negative impact on coral communities
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