576 research outputs found

    The homosexual orientation and investigations about the existence of components biological and genetics determinants

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    The male and female homosexual orientation has substantial prevalence in humans and can be explained by determinants of various levels: biological, genetic, psychological, social and cultural. However, the biological and genetic evidence have been the main hypotheses tested in scientific research in the world. This article aims to review research studies about the existence of genetic and biological evidence that determine homosexual orientation. Was conducted a review of the literature, using the database MedLine/PubMed and Google scholar. The papers and books were searched in Portuguese and English, using the following keywords: sexual orientation, sexual behavior, homosexuality, developmental Biology and genetics. Was selected papers of the last 22 years. Were found five main theories about the biological components: (1) fraternal birth order, (2) brain androgenization and 2D:4D ratio; (3) brain activation by pheromones; and (4) epigenetic inheritance; and four theories about the genetic components: (1) genetic polymorphism; (2) pattern of X-linked inheritance; (3) monozygotic twins; and (4) sexual antagonistic selection. Concluded that there were many scientific evidence found over time to explain some of biological and genetic components of homosexuality, especially in males. However, today, there is no definitive explanation about what are the determinants of homosexual orientation components

    Single-particle excitations in the BCS-BEC crossover region II: Broad Feshbach resonance

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    We apply the formulation developed in a recent paper [Y. Ohashi and A. Griffin, Phys. Rev. A {\bf 72}, 013601, (2005)] for single-particle excitations in the BCS-BEC crossover to the case of a broad Feshbach resonance. At T=0, we solve the Bogoliubov-de Gennes coupled equations taking into account a Bose condensate of bound states (molecules). In the case of a broad resonance, the density profile n(r)n(r), as well as the profile of the superfluid order parameter Δ~(r){\tilde \Delta}(r), are spatially spread out to the Thomas-Fermi radius, even in the crossover region. This order parameter Δ~(r){\tilde \Delta}(r) suppresses the effects of low-energy Andreev bound states on the rf-tunneling current. As a result, the peak energy in the rf-spectrum is found to occur at an energy equal to the superfluid order parameter Δ~(r=0){\tilde \Delta}(r=0) at the center of the trap, in contrast to the case of a narrow resonance, and in agreement with recent measurements. The LDA is found to give a good approximation for the rf-tunneling spectrum.Comment: 14 pages, 8 figure

    Precursor of Color Superconductivity

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    We investigate possible precursory phenomena of color superconductivity at finite temperature TT with an effective theory of QCD. It is found that the fluctuation of the diquark pair field exists with a prominent strength even well above the critical temperature TcT_c. We show that such a fluctuaiton forms a collective mode, the corresponding pole of which approaches the origin as TT is lowered to TcT_c in the complex energy plane. We discuss the possible relevance of the precursor to the observables to be detected in heavy-ion collisions.Comment: 4 pages, 5 figures, Talk presented at the XVIth International Conference on Particles and Nuclei (PANIC02), Osaka, Japan, Sep.30 - Oct.4, 2002, Uses espcrc1.st

    Experimental Limitations Using Reprogrammed Cells for Hematopoietic Differentiation

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    We review here our experiences with the in vitro reprogramming of somatic cells to induced pluripotent stem cells (iPSC) and subsequent in vitro development of hematopoietic cells from these iPSC and from embryonic stem cells (ESC). While, in principle, the in vitro reprogramming and subsequent differentiation can generate hematopoietic cell from any somatic cells, it is evident that many of the steps in this process need to be significantly improved before it can be applied to human cells and used in clinical settings of hematopoietic stem cell (HSC) transplantations

    Excitonic Phases from Weyl Semi-Metals

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    Systems with strong spin-orbit coupling, which competes with other interactions and energy scales, offer a fertile playground to explore new correlated phases of matter. Weyl semimetals are an example where the phenomenon leads to a low energy effective theory in terms of massless linearly dispersing fermions in three dimensions. In the absence of interactions chirality is a conserved quantum number, protecting the semi-metallic physics against perturbations that are translationally invariant. In this letter we show that the interplay between interaction and topology yields a novel chiral excitonic insulator. The state is characterized by a complex vectorial order parameter leading to a gapping out of the Weyl nodes. A striking feature is that it is ferromagnetic, with the phase of the order parameter determining the direction of the induced magnetic moment.Comment: 5 pages, 4 sets of figure

    Feshbach shape resonance for high Tc superconductivity in superlattices of nanotubes

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    The case of a Feshbach shape resonance in the pairing mechanism for high T c superconductivity in a crystalline lattice of doped metallic nanotubes is described. The superlattice of doped metallic nanotubes provides a superconductor with a strongly asymmetric gap. The disparity and different spatial locations of the wave functions of electrons in different subbands at the Fermi level should suppress the single electron impurity interband scattering giving multiband superconductivity in the clean limit. The Feshbach resonances will arise from the component single-particle wave functions out of which the electron pair wave function is constructed: pairs of wave functions which are time inverse of each other. The Feshbach shape resonance increases the critical temperature by tuning the chemical potential at the Lifshitz electronic topological transition (ETT) where the Fermi surface of one of the bands changes from the one dimensional (1D) to the two dimensional (2D) topology (1D/2D ETT).Comment: 6 pages, 4 figure

    Singlet Ground State and Magnetization Plateaus in Ba3_3Mn2_2O8_8

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    Magnetic susceptibility and the magnetization process have been measured in \green polycrystal. In this compound, the magnetic manganese ion exists as Mn5+^{5+} in a tetrahedral environment, and thus the magnetic interaction can be described by an S=1 Heisenberg model. The ground state was found to be a spin singlet with an excitation gap Δ/kB=11.2\Delta/k_{\rm B}=11.2 K. Magnetization plateaus were observed at zero and at half of the saturation magnetization. These results indicate that the present system can be represented by a coupled antiferromagnetic dimer model.Comment: 4 pages, 4 figures, jpsj styl

    Ballistic propagation of thermal excitations near a vortex in superfluid He3-B

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    Andreev scattering of thermal excitations is a powerful tool for studying quantized vortices and turbulence in superfluid He3-B at very low temperatures. We write Hamilton's equations for a quasiparticle in the presence of a vortex line, determine its trajectory, and find under wich conditions it is Andreev reflected. To make contact with experiments, we generalize our results to the Onsager vortex gas, and find values of the intervortex spacing in agreement with less rigorous estimates
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