13,776 research outputs found

    Ecojusticia, equidad y ética: retos para la orientación educativa y profesional

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    In social and environmental terms we live in precarious and uncertain times, where not only the sustainability of the planet rests in the balance, but also that of human existence. Many nation-states around the world talk of the importance of social cohesion, and are aware of the threat of environmental degradation, climate change, and ecological well-being. However, the dominating global policy discourse, particularly championed in the West, is located within a delimiting neo/liberal political framework. With a few noticeable exceptions, the influence of neo/liberal thinking continues to flourish in the contemporary career literature where there has been little deep critical engagement with the discourse of capitalist economics and how these impact human and environmental well-being. Often caught up in market-led discourses, and captured by the notion that ‘work sets you free’, educational and career guidance has been located within an uncritical economic frame. Its energies tend to be directed towards the preparation of individuals to make ‘good’ educational and occupational choices, underpinned by the need for ‘clients’ to acquire the skills and competencies demanded by employers (and the economy) (Bengtsson, 2011; Irving, 2018). The disjuncture between educational and career guidance and social and environmental justice (i.e. ecojustice) has rarely been breached. In this article, we seek to disrupt dominant discourses of the market that currently permeates thinking in education by identifying how an ecojustice perspective provides a forward looking and equitable foundation for educational and career guidance.En términos sociales y ambientales, vivimos en tiempos precarios e inciertos, donde no solo la sostenibilidad del planeta está en juego, sino también la de la existencia humana. Muchos estados-nación de todo el mundo hablan de la importancia de la cohesión social y son conscientes de la degradación ambiental, el cambio climático y la amenaza al bienestar ecológico y social. Sin embargo, el discurso dominante de la política global, particularmente defendido en Occidente, se sitúa dentro de un marco político neoliberal. Con algunas notables excepciones, la influencia del pensamiento neoliberal continúa siendo hegemónico en el campo de la educación y de la orientación profesional, donde en términos generales ha habido poco compromiso crítico profundo con el discurso de la economía capitalista y cómo este impacta sobre el bienestar humano y ambiental. A menudo atrapada en discursos dirigidos por el mercado y por la noción de que "el trabajo nos hace libres", la orientación educativa y profesional se ha ubicado dentro de un marco económico acrítico. Se tiende a preparar a los individuos para tomar "buenas" decisiones educativas y ocupacionales, respaldadas por la necesidad de que adquieran las habilidades y competencias exigidas por los empleadores (y la economía) (Bengtsson, 2011; Irving, 2018). La disyuntiva entre la orientación educativa y profesional y la justicia social y ambiental (la ecojusticia) rara vez se ha abordado. En este artículo cuestionamos los discursos dominantes del mercado que actualmente impregnan el pensamiento en educación, y proponemos la adopción de una perspectiva de ecojusticia que proporciona una guía para el futuro y contribuye a promover la equidad desde la orientación educativa y profesional

    Perturbations in Hybrid Loop Quantum Cosmology: Continuum Limit in Fourier Space

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    We analyze the passage to a continuum limit of the mode spectrum of primordial perturbations around flat cosmological spacetimes in hybrid Loop Quantum Cosmology, showing that this limit can be reached even if one starts by considering a finite fiducial cell as spatial slice. We focus our attention on regimes in which the background cosmology follows the effective dynamics of Loop Quantum Cosmology, although we comment on extensions of our arguments beyond this regime, as well as to some formalisms other than the hybrid approach. Whereas the perturbed system can be described in an invariant way under changes of the fiducial volume using the standard variables of the improved prescription for Loop Quantum Cosmology, we show that the desired continuum limit can be established by means of scaling transformations of the physical volume when this volume grows unboundedly. These transformations lead to a model with a continuum of modes and independent of any scale of reference for the physical volume. For the sake of comparison, we also consider an alternative road to the continuum in Fourier space that has been employed in geometrodynamics and is based on the use of scaling transformations of the fiducial volume, together with variables that are independent of them.Comment: 13 page

    Application of Species Distribution Modeling for Avian Influenza surveillance in the United States considering the North America Migratory Flyways.

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    Highly Pathogenic Avian Influenza (HPAI) has recently (2014-2015) re-emerged in the United States (US) causing the largest outbreak in US history with 232 outbreaks and an estimated economic impact of $950 million. This study proposes to use suitability maps for Low Pathogenic Avian Influenza (LPAI) to identify areas at high risk for HPAI outbreaks. LPAI suitability maps were based on wild bird demographics, LPAI surveillance, and poultry density in combination with environmental, climatic, and socio-economic risk factors. Species distribution modeling was used to produce high-resolution (cell size: 500m x 500m) maps for Avian Influenza (AI) suitability in each of the four North American migratory flyways (NAMF). Results reveal that AI suitability is heterogeneously distributed throughout the US with higher suitability in specific zones of the Midwest and coastal areas. The resultant suitability maps adequately predicted most of the HPAI outbreak areas during the 2014-2015 epidemic in the US (i.e. 89% of HPAI outbreaks were located in areas identified as highly suitable for LPAI). Results are potentially useful for poultry producers and stakeholders in designing risk-based surveillance, outreach and intervention strategies to better prevent and control future HPAI outbreaks in the US

    Breached pairing in trapped three-color atomic Fermi gases

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    We introduce an exactly solvable model for trapped three-color atom gases. Applications to a cigar-shaped trapped cold fermions reveal a complex structure of breached pairing phases. We find two competing superfluid phases at weak and intermediate couplings, each one with two color pair condensates, that can be distinguished from density profile measurements.Comment: 4 pages, 5 figure

    Modeling effective FRW cosmologies with perfect fluids from states of the hybrid quantum Gowdy model

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    We employ recently developed approximation methods in the hybrid quantization of the Gowdy T3T^3 model with linear polarization and a massless scalar field to obtain physically interesting solutions of this inhomogeneous cosmology. More specifically, we propose approximate solutions of the quantum Gowdy model constructed in such a way that, for the Hamiltonian constraint, they effectively behave as those corresponding to a flat homogeneous and isotropic universe filled with a perfect fluid, even though these quantum states are far from being homogeneous and isotropic. We analyze how one can get different perfect fluid effective behaviors, including the cases of dust, radiation, and cosmological constant.Comment: Version accepted for publication in PR

    Griffiths phases in the strongly disordered Kondo necklace model

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    The effect of strong disorder on the one-dimensional Kondo necklace model is studied using a perturbative real-space renormalization group approach which becomes asymptotically exact in the low energy limit. The phase diagram of the model presents a random quantum critical point separating two phases; the {\em random singlet phase} of a quantum disordered XY chain and the random Kondo phase. We also consider an anisotropic version of the model and show that it maps on the strongly disordered transverse Ising model. The present results provide a rigorous microscopic basis for non-Fermi liquid behavior in disordered heavy fermions due to Griffiths phases.Comment: 4 pages, 4 figure

    Fermions in Hybrid Loop Quantum Cosmology

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    This work pioneers the quantization of primordial fermion perturbations in hybrid Loop Quantum Cosmology (LQC). We consider a Dirac field coupled to a spatially flat, homogeneous, and isotropic cosmology, sourced by a scalar inflaton, and treat the Dirac field as a perturbation. We describe the inhomogeneities of this field in terms of creation and annihilation variables, chosen to admit a unitary evolution if the Dirac fermion were treated as a test field. Considering instead the full system, we truncate its action at quadratic perturbative order and construct a canonical formulation. In particular this implies that, in the global Hamiltonian constraint of the model, the contribution of the homogeneous sector is corrected with a quadratic perturbative term. We then adopt the hybrid LQC approach to quantize the full model, combining the loop representation of the homogeneous geometry with the Fock quantization of the inhomogeneities. We assume a Born-Oppenheimer ansatz for physical states and show how to obtain a Schr\"odinger equation for the quantum evolution of the perturbations, where the role of time is played by the homogeneous inflaton. We prove that the resulting quantum evolution of the Dirac field is indeed unitary, despite the fact that the underlying homogeneous geometry has been quantized as well. Remarkably, in such evolution, the fermion field couples to an infinite sequence of quantum moments of the homogeneous geometry. Moreover, the evolved Fock vacuum of our fermion perturbations is shown to be an exact solution of the Schr\"odinger equation. Finally, we discuss in detail the quantum backreaction that the fermion field introduces in the global Hamiltonian constraint. For completeness, our quantum study includes since the beginning (gauge-invariant) scalar and tensor perturbations, that were studied in previous works.Comment: 29 pages. It matches published versio

    Modified FRW cosmologies arising from states of the hybrid quantum Gowdy model

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    We construct approximate solutions of the hybrid quantum Gowdy cosmology with three-torus topology, linear polarization, and local rotational symmetry, in the presence of a massless scalar field. More specifically, we determine some families of states for which the complicated inhomogeneous and anisotropic Hamiltonian constraint operator of the Gowdy model is approximated by a much simpler one. Our quantum states follow the dynamics governed by this simpler constraint, while being at the same time also approximate solutions of the full Gowdy model. This is so thanks to the quantum correlations that the considered states present between the isotropic and anisotropic sectors of the model. Remarkably, this simpler constraint can be regarded as that of a flat Friedmann-Robertson-Walker universe filled with different kinds of perfect fluids and geometrically corrected by homogeneous and isotropic curvature-like terms. Therefore, our quantum states, which are intrinsically inhomogeneous, admit approximate homogeneous and isotropic effective descriptions similar to those considered in modified theories of gravity.Comment: Version accepted for publication in PR

    XASH genes promote neurogenesis in Xenopus embryos

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    Neural development in Drosophila is promoted by a family of basic helix-loop-helix (bHLH) transcription factors encoded within the Achaete Scute-Complex (AS-C). XASH- 3, a Xenopus homolog of the Drosophila AS-C genes, is expressed during neural induction within a portion of the dorsal ectoderm that gives rise to the neural plate and tube. Here, we show that XASH-3, when expressed with the promiscuous binding partner XE12, specifically activates the expression of neural genes in naive ectoderm, suggesting that XASH-3 promotes neural development. Moreover, XASH-3/XE12 RNA injections into embryos lead to hypertrophy of the neural tube. Interestingly, XASH-3 misexpression does not lead to the formation of ectopic neural tissue in ventral regions, suggesting that the domain of XASH proneural function is restricted in the embryo. In contrast to the neural inducer noggin, which permanently activates the NCAM gene, the activation of neural genes by XASH-3/XE12 is not stable in naive ectoderm, yet XASH-3/XE12 powerfully and stably activates NCAM, Neurofilament and type III β-tubulin gene expression in noggintreated ectoderm. These results show that the XASH-3 promotes neural development, and suggest that its activity depends on additional factors which are induced in ectoderm by factors such as noggin
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