3,218 research outputs found

    Wearable Technology in Sports and the Need for Greater Protection

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    Acerca de los Problemas de Acceso al Campo y las Relaciones con Informantes Clave en Instituciones Universitarias

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    En esta comunicación presentamos algunas notas metodológicas sobre las particularidades que asume el trabajo de investigación social acerca de las instituciones universitarias. Elaboramos estas reflexiones a partir de un estudio comparado sobre las políticas de vinculación con el sector productivo desarrolladas en los años noventa por cuatro universidades argentinas de perfiles organizacionales diferentes seleccionadasad hoc, estudio llevado a cabo en el Centro de Estudios Avanzados de la Universidad de Buenos Aire

    Introgression Among Cultivated and Wild Grapevine in Tuscany

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    Wild grapevine, Vitis vinifera L. subsp. sylvestris (Gmelin, Hegi) is spontaneous to Europe and common in Tuscany. In this study, wild grapevines were identified in 22 populations from eight locations in Tuscan Maremma (Grosseto and Siena province). The plants were propagated by cuttings, collected in a vineyard, genotyped by nuclear simple sequence repeats (SSRs), chloroplast SSRs and single nucleotide polymorphisms (SNPs), and compared to locally cultivated varieties (Vitis vinifera L. subsp. sativa) and to non-vinifera and non-vitis genotypes. The identity analysis revealed that some individuals were redundant genotypes, suggesting natural vegetative propagation. In addition, four of the supposed V.v. sylvestris were in fact naturalized V.v. sativa. The majority of putative sylvestris genotypes had chlorotype A, while the remainder had chlorotype D, as the majority of Vitis vinifera subsp. sativa cultivated in Italy. Some of the recovered sylvestris genotypes appeared to be natural crosses with cultivated grapevine varieties in Tuscany, and their chlorotype suggests a higher pollen flow from sativa to the sylvestris genotypes than in the opposite direction. In addition, other genotypes appeared to be crosses within sylvestris, sylvestris-sativa or sylvestris-sylvestris siblings, or equivalent relationships. These relationships suggest a noticeably level of sexual reproductive activities among sylvestris and sylvestris-sativa genotypes. A cluster and structure analysis clearly differentiated the true sylvestris from the sativa, and the nonvinifera or non-vitis genotypes, and also highlighted a possible introgression of sylvestris into some Italian and French cultivated varieties. The results therefore suggest that, in addition to the primary ancient center of domestication from the Near East to Central Asia, the introgression among cultivated and wild grapevine occurred in other centers of diversification along the migration routes, contributing to the domestication processes, and suggesting that these processes are still ongoing despite the reduction in populations of sylvestris. The results also highlight that the GrapeReSeq 18K Vitis genotyping chip are suitable for non-vitis genotyping and that the range of SNPs heterozygosity in sylvestris appears to be up to 6% less and does not overlap the heterozygosity range of sativa genotypes

    The effect of the environment on the Faber Jackson relation

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    We investigate the effect of the environment on the Faber Jackson (FJ) relation, using a sample of 384 nearby elliptical galaxies and estimating objectively their environment on the typical scale of galaxy clusters. We show that the intrinsic scatter of the FJ is significantly reduced when ellipticals in high density environments are compared to ellipticals in low density ones. This result, which holds on a limited range of overdensities, is likely to provide an important observational link between scaling relations and formation mechanisms in galaxies.Comment: accepted by Ap

    The interplay between voluntary vaccination and reduction of risky behavior: a general behavior-implicit SIR model for vaccine preventable infections

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    The onset in the last 15 years of behavioral epidemiology has opened many new avenues for epidemiological modelers. In this manuscript we first review two classes of behavioral epidemiology models for vaccine preventable diseases, namely behaviour-implicit SIR models with prevalence-dependent vaccination (at birth and among older individuals), and prevalence-dependent contact rate. Subsequently, we briefly propose a general framework of behavior–dependent nonlinear and linear Forces of Infection (FoI) valid for a vast family of infectious diseases, and including delays and ‘epidemic memory’ effects. Finally and mainly, we develop a new general behavioral SIR model. This model combines the two aforementioned types of behavioral phenomena, previously considered only separately, into a single unified model for behavioral responses. The resulting model allows to develop a general phenomenological theory of the effects of behavioral responses within SIR models for endemic infections. In particular, the model allows to complete the picture about the complicate interplay between different behavioral responses acting on different epidemiological parameters in triggering sustained oscillations of vaccine coverage, risky behavior, and infection prevalence

    Existence and uniqueness of limit cycles in a class of second order ODE's with inseparable mixed terms

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    We prove a uniqueness result for limit cycles of the second order ODE x¨+x˙ϕ(x,x˙)+g(x)=0\ddot x + \dot x \phi(x,\dot x) + g(x) = 0. Under mild additional conditions, we show that such a limit cycle attracts every non-constant solution. As a special case, we prove limit cycle's uniqueness for an ODE studied in \cite{ETA} as a model of pedestrians' walk. This paper is an extension to equations with a non-linear g(x)g(x) of the results presented in \cite{S}

    Searching for dark photons at the LHeC and FCC-he

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    Extensions of the Standard Model (SM) gauge group with a new U(1)X predict an additional gauge boson. Through kinetic mixing with the SM photons featured by a coupling ε, the ensuing so-called dark photons γ′, which acquire mass as a result of the breaking of the gauge group U(1)X, can interact with the SM field content. These massive dark photons can therefore decay to pairs of leptons, hadrons, or quarks, depending on their mass mγ′. In this work, we discuss searches for dark photons in the mass range around and below 1 GeV at the LHeC and FCC-he colliders. The signal is given by the displaced decays of the long-lived dark photon into two charged particles. We discuss the impact of conceivable irreducible (SM and machine-related) backgrounds and different signal efficiencies. Our estimates show that the LHeC and FCC-he can test a domain that is complementary to other present and planned experiments

    The Fundamental Plane of Early-Type Galaxies as a Confounding Correlation

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    Early-type galaxies are characterized by many scaling relations. One of them, the so-called fundamental plane is a relatively tight correlation between three variables, and has resisted a clear physical understanding despite many years of intensive research. Here, we show that the correlation between the three variables of the fundamental plane can be the artifact of the effect of another parameter influencing all, so that the fundamental plane may be understood as a confounding correlation. Indeed, the complexity of the physics of galaxies and of their evolution suggests that the main confounding parameter must be related to the level of diversification reached by the galaxies. Consequently, many scaling relations for galaxies are probably evolutionary correlations

    From Sarcopenia to Frailty: The Pathophysiological Basis and Potential Target Molecules of Intervention

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    Skeletal muscle is not only an endocrine organ but also one of core components of muscloskeletal system. Sarcopenia refers to a decline in the skeletal muscle mass and function. The former involves the size and number of changes in two types of myofibers, lower satellite cell density, and regeneration ability. The latter shows a loss of muscle strength. Frailty is a geriatric syndrome with multisystem impairment associated with increased vulnerability to stressors. Sarcopenia increases the risk of frailty and may be one of the major causes of physical frailty phenotype. Sarcopenia is also potentially associated with cognitive frailty phenotype. Aging might be the common underlying pathophysiology of sarcopenia and frailty. Therefore, there are some potential target molecules in aging-related signaling pathways that might be associated with sarcopenia and frailty. Nevertheless, sarcopenia can mediate metabolism and promote accelerate systemic aging, frailty, and age-related diseases by myokines in an endocrine manner. Lifestyle interventions (resistance exercise and dietary restriction) of gerontoscience are effective in the prevention of sarcopenia. Some pharmacological agents are registered in different phases of clinical trials for sarcopenia intervention. Phytochemicals, mTOR inhibitors, metformin and acarbose, NAD precursors, and sirtuin activators demonstrated that multiple target antiaging effects might also have preventive and therapeutic perspectives on sarcopenia and frailty
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