1,023 research outputs found

    Metabolic syndrome before puberty: Myth or reality?

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    Metabolic syndrome (MetS) is defined as a cluster of alterations related with insulin resistance (obesity, dyslipidemia, hypertension, and impaired glucose metabolism), which are associated with a higher risk of cardiovascular disease in adults. Several definitions have been proposed for older children and adolescents. However, no definitions have been made in accordance with pubertal status, and those in prepubertal state have not received attention enough, despite there are data suggesting the early presence of risk factors. The new insights concerning healthy and unhealthy metabolic status or the addition of novel metabolic risk biomarkers, may contribute to the knowledge about the development of MetS in children. This manuscript reviews the available evidence on MetS during childhood, focusing on the prepubertal period

    A new parametrization of the neutrino mixing matrix for neutrino oscillations

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    In this paper we study three active neutrino oscillations, favored by recent data from SuperK and SNO, using a new parametrization of the lepton mixing matrix VV constructed from a linear combination of the unit matrix II, and a hermitian unitary matrix UU, that is, V=cosθI+isinθUV = \cos\theta I + i\sin \theta U. There are only three real parameters in VV including the parameter θ\theta. It is interesting to find that experimental data on atmospheric neutrino dictates the angle θ\theta to be π/4\pi/4 such that the νμ\nu_\mu and ντ\nu_\tau mixing is maximal. The solar neutrino problem is solved via the MSW effect with a small mixing angle, with UU depending on one small parameter ϵ\epsilon. The resulting mixing matrix with just two parameters (θ\theta and ϵ\epsilon) predicts that the oscillating probabilities for νeνμ\nu_e\to \nu_\mu and νeντ\nu_e \to \nu_\tau to be equal and of the order 2ϵ2=(0.252.5)×1032\epsilon^2 = (0.25\sim 2.5)\times 10^{-3}. The measurement of CP asymmetries at the proposed Neutrino Factories would also provide a test of our parametrization.Comment: 10 pages, Retex, no figure

    Inflation with racetrack superpotential and matter field

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    Several models of inflation with the racetrack superpotential for the volume modulus coupled to a matter field are investigated. In particular, it is shown that two classes of racetrack inflation models, saddle point and inflection point ones, can be constructed in a fully supersymmetric framework with the matter field F-term as a source of supersymmetry breaking and uplifting. Two models of F-term supersymmetry breaking are considered: the Polonyi model and the quantum corrected O'Raifeartaigh model. In the former case, both classes of racetrack inflation models differ significantly from the corresponding models with non-supersymmetric uplifting. The main difference is a quite strong dominance of the inflaton by the matter field. In addition, fine-tuning of the parameters is relaxed as compared to the original racetrack models. In the case of the racetrack inflation models coupled to the O'Raifeartaigh model, the matter field is approximately decoupled from the inflationary dynamics. In all of the above models the gravitino mass is larger than the Hubble scale during inflation. The possibility of having the gravitino much lighter than the Hubble scale is also investigated. It is very hard to construct models with light gravitino in which the volume modulus dominates inflation. On the other hand, models in which the inflationary dynamics is dominated by the matter field are relatively simple and seem to be more natural.Comment: 40 pages, 13 figures, references added, typos corrected, version to be publishe

    Functional characterization of E- and P-cadherin in invasive breast cancer cells

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    Background: Alterations in the cadherin-catenin adhesion complexes are involved in tumor initiation, progression and metastasis. However, the functional implication of distinct cadherin types in breast cancer biology is still poorly understood. Methods: To compare the functional role of E-cadherin and P-cadherin in invasive breast cancer, we stably transfected these molecules into the MDA-MB-231 cell line, and investigated their effects on motility, invasion and gene expression regulation. Results: Expression of either E-and P-cadherin significantly increased cell aggregation and induced a switch from fibroblastic to epithelial morphology. Although expression of these cadherins did not completely reverse the mesenchymal phenotype of MDA-MB-231 cells, both E-and P-cadherin decreased fibroblast-like migration and invasion through extracellular matrix in a similar way. Moreover, microarray gene expression analysis of MDA-MB-231 cells after expression of E-and P-cadherins revealed that these molecules can activate signaling pathways leading to significant changes in gene expression. Although the expression patterns induced by E-and P-cadherin showed more similarities than differences, 40 genes were differentially modified by the expression of either cadherin type. Conclusion: E-and P-cadherin have similar functional consequences on the phenotype and invasive behavior of MDA-MB-231 cells. Moreover, we demonstrate for the first time that these cadherins can induce both common and specific gene expression programs on invasive breast cancer cells. Importantly, these identified genes are potential targets for future studies on the functional consequences of altered cadherin expression in human breast cancer

    Superbeams versus Neutrino Factories

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    We compare the physics potential of planned superbeams with the one of neutrino factories. Therefore, the experimental setups as well as the most relevant uncertainties and errors are considered on the same footing as much as possible. We use an improved analysis including the full parameter correlations, as well as statistical, systematical, and degeneracy errors. Especially, degeneracies have so far not been taken into account in a numerical analysis. We furthermore include external input, such as improved knowledge of the solar oscillation parameters from the KamLAND experiment. This allows us to determine the limiting uncertainties in all cases. For a specific comparison, we choose two representatives of each class: For the superbeam, we take the first conceivable setup, namely the JHF to SuperKamiokande experiment, as well as, on a longer time scale, the JHF to HyperKamiokande experiment. For the neutrino factory, we choose an initially conceivable setup and an advanced machine. We determine the potential to measure the small mixing angle sin^2 2 theta_{13}, the sign of Delta m^2_{31}, and the leptonic CP phase \deltacp, which also implies that we compare the limitations of the different setups. We find interesting results, such as the complete loss of the sensitivity to the sign of Delta m^2_{31} due to degeneracies in many cases.Comment: Revised version with JHF energy resolution corrected, discussion of detector issues added (App. B), and references added. Summary and conclusions unchanged. 51 pages, 28 figures, 4 table

    Epithelial-mesenchymal transitions: the importance of changing cell state in development and disease

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    The events that convert adherent epithelial cells into individual migratory cells that can invade the extracellular matrix are known collectively as epithelial-mesenchymal transition (EMT). Throughout evolution, the capacity of cells to switch between these two cellular states has been fundamental in the generation of complex body patterns. Here, we review the EMT events that build the embryo and further discuss two prototypical processes governed by EMT in amniotes: gastrulation and neural crest formation. Cells undergo EMT to migrate and colonize distant territories. Not surprisingly, this is also the mechanism used by cancer cells to disperse throughout the body

    Models of Modular Inflation and Their Phenomenological Consequences

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    We study models of modular inflation of the form expected to arise from low energy effective actions of superstring theories. We argue on general grounds that the most likely models of modular slow-roll inflation are small field models in which the inflaton moves about a Planck distance from an extremum of the potential. We then focus on models in which the inflaton is the bosonic component of a single (complex) chiral superfield and explain the generic difficulties in designing small field models of modular inflation. We then show that if the Kaehler potential (KP) of the inflaton is logarithmic as in perturbative string theories, then it is not possible to satisfy the slow-roll conditions for any superpotential. We find that if the corrections to the KP are large enough so it can be approximated by a canonical KP in the vicinity of the extremum, then viable slow-roll inflation is possible. In this case, several parameters have to be tuned to a fraction of a percent. We give a prescription for designing successful small field supergravity models of inflation when the KP is canonical and calculate the slow-roll parameters from the superpotential parameters. Our results strengthen the case for models in which the moduli slowly roll about a Planck distance from a relatively high scale extremum that is located in the vicinity of the central region of moduli space units. Generic models of this class predict a red spectrum of scalar perturbations and negligible spectral index running. They also predict a characteristic suppression of tensor perturbations despite the high scale of inflation. Consequently, a detection of primordial tensor anisotropies or spectral index running in cosmic microwave background observations in the foreseeable future will rule out this entire class of modular inflation models.Comment: 35 pages, 1 figur

    Synergies between the first-generation JHF-SK and NuMI superbeam experiments

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    We discuss synergies in the combination of the first-generation JHF to Super-Kamiokande and NuMI off-axis superbeam experiments. With synergies we mean effects which go beyond simply adding the statistics of the two experiments. As a first important result, we do not observe interesting synergy effects in the combination of the two experiments as they are planned right now. However, we find that with minor modifications, such as a different NuMI baseline or a partial antineutrino running, one could do much richer physics with both experiments combined. Specifically, we demonstrate that one could, depending on the value of the solar mass squared difference, either measure the sign of the atmospheric mass squared difference or CP violation already with the initial stage experiments. Our main results are presented in a way that can be easily interpreted in terms of the forthcoming KamLAND result.Comment: 29 pages, 10 figure

    Galilean quantum gravity with cosmological constant and the extended q-Heisenberg algebra

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    We define a theory of Galilean gravity in 2+1 dimensions with cosmological constant as a Chern-Simons gauge theory of the doubly-extended Newton-Hooke group, extending our previous study of classical and quantum gravity in 2+1 dimensions in the Galilean limit. We exhibit an r-matrix which is compatible with our Chern-Simons action (in a sense to be defined) and show that the associated bi-algebra structure of the Newton-Hooke Lie algebra is that of the classical double of the extended Heisenberg algebra. We deduce that, in the quantisation of the theory according to the combinatorial quantisation programme, much of the quantum theory is determined by the quantum double of the extended q-deformed Heisenberg algebra.Comment: 22 page

    Neutral currents and tests of three-neutrino unitarity in long-baseline experiments

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    We examine a strategy for using neutral current measurements in long-baseline neutrino oscillation experiments to put limits on the existence of more than three light, active neutrinos. We determine the relative contributions of statistics, cross section uncertainties, event misidentification and other systematic errors to the overall uncertainty of these measurements. As specific case studies, we make simulations of beams and detectors that are like the K2K, T2K, and MINOS experiments. We find that the neutral current cross section uncertainty and contamination of the neutral current signal by charge current events allow a sensitivity for determining the presence of sterile neutinos at the 0.10--0.15 level in probablility.Comment: 24 pages, Latex2e, uses graphicx.sty, 2 postscript figures. Submitted to the Neutrino Focus Issue of New Journal Physics at http://www.njp.or
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