4,322 research outputs found

    Gravitational Waves from Wobbling Pulsars

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    The prospects for detection of gravitational waves from precessing pulsars have been considered by constructing fully relativistic rotating neutron star models and evaluating the expected wave amplitude hh from a galactic source. For a "typical" neutron matter equation of state and observed rotation rates, it is shown that moderate wobble angles may render an observable signal from a nearby source once the present generation of interferometric antennas becomes operative.Comment: PlainTex, 7 pp. , no figures, IAG/USP Rep. 6

    La influencia de huertos agroforestales en la sostenibilidad ambiental, en la soberanía alimentaria y en el empoderamiento de las mujeres de una comunidad de Manaus, Amazonas, Brasil.

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    Este trabajo evalúo el impacto de la adopción de huertos agroforestales en el empoderamiento de las mujeres y en la sostenibilidad ambiental de una comunidad periurbana de Manaus, Amazonas, Brasil

    Temperature oscillations of magnetization observed in nanofluid ferromagnetic graphite

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    We report on unusual magnetic properties observed in the nanofluid room-temperature ferromagnetic graphite (with an average particle size of l=10nm). More precisely, the measured magnetization exhibits a low-temperature anomaly (attributed to manifestation of finite size effects below the quantum temperature) as well as pronounced temperature oscillations above T=50K (attributed to manifestation of the hard-sphere type pair correlations between ferromagnetic particles in the nanofluid)

    Watersheds are Schramm-Loewner Evolution curves

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    We show that in the continuum limit watersheds dividing drainage basins are Schramm-Loewner Evolution (SLE) curves, being described by one single parameter κ\kappa. Several numerical evaluations are applied to ascertain this. All calculations are consistent with SLEκ_\kappa, with κ=1.734±0.005\kappa=1.734\pm0.005, being the only known physical example of an SLE with κ<2\kappa<2. This lies outside the well-known duality conjecture, bringing up new questions regarding the existence and reversibility of dual models. Furthermore it constitutes a strong indication for conformal invariance in random landscapes and suggests that watersheds likely correspond to a logarithmic Conformal Field Theory (CFT) with central charge c7/2c\approx-7/2.Comment: 5 pages and 4 figure

    The Highly Miniaturised Radiation Monitor

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    We present the design and preliminary calibration results of a novel highly miniaturised particle radiation monitor (HMRM) for spacecraft use. The HMRM device comprises a telescopic configuration of active pixel sensors enclosed in a titanium shield, with an estimated total mass of 52 g and volume of 15 cm3^3. The monitor is intended to provide real-time dosimetry and identification of energetic charged particles in fluxes of up to 108^8 cm2^{-2} s1^{-1} (omnidirectional). Achieving this capability with such a small instrument could open new prospects for radiation detection in space.Comment: 17 pages, 15 figure

    Anomalous Hall effect in superconductors with spin-orbit interaction

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    We calculate the anomalous Hall conductance of superconductors with spin-orbit interaction and with either uniform or local magnetization. In the first case we consider a uniform ferromagnetic ordering in a spin triplet superconductor, while in the second case we consider a conventional s-wave spin singlet superconductor with a magnetic impurity (or a diluted set of magnetic impurities). In the latter case we show that the anomalous Hall conductance can be used to track the quantum phase transition, that occurs when the spin coupling between the impurity and electronic spin density exceeds a certain critical value. In both cases we find that for large spin-orbit coupling the superconductivity is destroyed and the Hall conductance oscillates strongly.Comment: 10 pages, 6 figure

    Caracterização da matéria orgânica e mineralógica dos solos das bacias dos rios Acre e Iaco, estado do Acre.

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    Na região Amazônica, o uso da terra tem levado, no decorrer dos anos, a um mosaico de agroecossistemas que caracterizam e registram a resposta do ambiente às suas alterações. Os conhecimentos pedoambientais e a ação antrópica nestes ambientes são de importância fundamental para o melhor uso dos ecossistemas. O objetivo do presente trabalho foi estudar duas bacias contíguas com componentes pedológicos distintos utilizando como base de estratificação a matéria orgânica e a mineralogia de forma a subsidiar o manejo dos solos nesta região. Nos perfis descritos e coletados nas duas bacias de estudo, bacia do rio Acre e Iaco, foram realizados: extração e fracionamento de substâncias húmicas, fracionamento físico da matéria orgânica para obtenção da fração leve e análises de difratometria por raios X, para análises mineralógicas. Os resultados revelaram o domínio de frações húmicas em superfície, sempre reduzindo em profundidade e diferenças mineralógicas nas bacias estudadas, onde a bacia do rio Acre apresentou minerais mais evoluídos como caulinita e gibbsita e na bacia do rio Iaco, mineralogia do tipo 2:1 como vermiculita e esmectita, que revela o caráter jovens de seus solos e uma maior vulnerabilidade a ação antrópica

    Simultaneous Papillary Carcinoma in Thyroglossal Duct Cyst and Thyroid

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    Thyroglossal duct cyst (TDC) is a cystic expansion of a remnant of the thyroglossal duct tract. Carcinomas in the TDC are extremely rare and are usually an incidental finding after the Sistrunk procedure. In this report, an unusual case of a 36-year-old woman with concurrent papillary thyroid carcinoma arising in the TDC and on the thyroid gland is presented, followed by a discussion of the controversies surrounding the possible origins of a papillary carcinoma in the TDC, as well as the current management options
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