1,600 research outputs found

    Simulation of the arterial elasticity influence on the Ambulatory Arterial Stiffness Index AASI

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    Recientemente se propuso un índice de rigidez arterial denominado AASI (Ambulatory Arterial Stiffness Index) derivado de mediciones ambulatorias de presión arterial durante 24 horas. Su asociación como índice de rigidez y la infl uencia estadística de la dispersión en los valores presivos continúa bajo discusión. Proponemos estudiar estas controversias en el contexto de un modelo estadístico. Se realizó una simulación con valores similares a los de pacientes de arterias normales, rígidas y compliantes, utilizando 3 curvas exponenciales presión-diámetro. Se generaron diámetros pulsátiles aleatorios siguiendo distribuciones normales y se obtuvieron presiones sistólicas y diastólicas en tiempos paramétricos equivalentes a 24 horas. Se calculó el AASI como uno menos la pendiente de la regresión de presión arterial sistólica y diastólica. El AASI del grupo normal resultó 0,42, aumentó a 0,50 en el rígido y disminuyó a 0,34 en el compliante (siempre con r2>0,9). Disminuir la dispersión del rango de presiones provocó una disminución de r2 en la regresión de la nube de puntos de presión sistólica y diastólica, aumentando artifi cialmente el AASI. Por primera vez la elasticidad no-lineal de la pared arterial ayuda a explicar la asociación del AASI como índice de rigidez arterial. La simulación corrobora que la dispersión de los valores presivos condicionan el cálculo del AASI debido a su naturaleza estadística.Recently, an arterial stiffness index called AASI (Ambulatory Arterial Stiffness Index) calculated from ambulatory blood pressure measurements during 24 hours was proposed. The associations with arterial stiffness and the pressure dispersion dependence remain under discussion. We propose to study these controversies in a statistical model framework. A simulation was performed including values similar to the ones in patients with normal, rigid and compliant arteries. Three exponential curves of pressure-diameter were simulated. Based on diameters randomly generated following normal distributions, systolic and diastolic pressures were calculated in a 24h parametric time. AASI was calculated as one minus the slope of the regression of systolic to diastolic pressure. The AASI for the normal group was 0,42, increased to 0,50 in the rigid group and decreased to 0,34 in the compliant case (always r2>0,9). A dispersion decrease in the pressure values was followed by an r2 decrease in the diastolic vs systolic pressure regression, artifi cially increasing AASI. For the fi rst time the non-linearity of the arterial wall helps to explain the association of AASI with a stiffness index. The simulation corroborates that 24 h pressure variability conditions AASI values due to its statistical nature

    Association of complement receptor 2 polymorphisms withinnate resistance to HIV-1 infection

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    HIV-1 induces activation of complement through the classical and lectin pathways. However, the virus incorporates several membrane-bound or soluble regulators of complement activation (RCA) that inactivate complement. HIV-1 can also use the complement receptors (CRs) for complement-mediated antibody-dependent enhancement of infection (Ć-ADE). We hypothesize that hypofunctional polymorphisms in RCA or CRs may protect from HIV-1 infection. For this purpose, 139 SNPs located in 19 RCA and CRs genes were genotyped in a population of 201 Spanish HIV-1-exposed seronegative individuals (HESN) and 250 HIV-1-infected patients. Two SNPs were associated with infection susceptibility, rs1567190 in CR2 (odds ratio (OR)=2.27, P=1 × 10-4) and rs2842704 in C4BPA (OR=2.11, P=2 × 10-4). To replicate this finding, we analyzed a cohort of Italian, sexually HESN individuals. Although not significant (P=0.25, OR=1.57), similar genotypic proportions were obtained for the CR2 marker rs1567190. The results of the two association analyses were combined through a random effect meta-analysis, with a significant P-value of 2.6x10-5 (OR=2.07). Furthermore, we found that the protective CR2 genotype is correlated with lower levels CR2 mRNA as well as differences in the ratio of the long and short CR2 isoforms.Genes and Immunity advance online publication, 8 January 2015; doi:10.1038/gene.2014.71.This work was supported by Spanish Health Ministry [PI021476, PI051778 and PI10/01232 to JF, JAP and ACar]; Instituto de Salud Carlos III-RETIC [RD06/006 to JAP]; Fundació Marató TV3 [020730 and 020732 to JF and ACar]; Junta de Andalucía [PI-0335/2009 to ACar]; Fundación Progreso y Salud of the Consejería de Salud de la Junta de Andalucía [AI-0021 to JAP]; and Universidad de Jaen [UJA2013/10/03 to ACar]

    Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

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    Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis

    Search for heavy resonances decaying to two Higgs bosons in final states containing four b quarks

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    A search is presented for narrow heavy resonances X decaying into pairs of Higgs bosons (H) in proton-proton collisions collected by the CMS experiment at the LHC at root s = 8 TeV. The data correspond to an integrated luminosity of 19.7 fb(-1). The search considers HH resonances with masses between 1 and 3 TeV, having final states of two b quark pairs. Each Higgs boson is produced with large momentum, and the hadronization products of the pair of b quarks can usually be reconstructed as single large jets. The background from multijet and t (t) over bar events is significantly reduced by applying requirements related to the flavor of the jet, its mass, and its substructure. The signal would be identified as a peak on top of the dijet invariant mass spectrum of the remaining background events. No evidence is observed for such a signal. Upper limits obtained at 95 confidence level for the product of the production cross section and branching fraction sigma(gg -> X) B(X -> HH -> b (b) over barb (b) over bar) range from 10 to 1.5 fb for the mass of X from 1.15 to 2.0 TeV, significantly extending previous searches. For a warped extra dimension theory with amass scale Lambda(R) = 1 TeV, the data exclude radion scalar masses between 1.15 and 1.55 TeV

    Search for supersymmetry in events with one lepton and multiple jets in proton-proton collisions at root s=13 TeV

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    Measurement of the top quark mass using charged particles in pp collisions at root s=8 TeV

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    Development and validation of HERWIG 7 tunes from CMS underlying-event measurements

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    This paper presents new sets of parameters (“tunes”) for the underlying-event model of the HERWIG7 event generator. These parameters control the description of multiple-parton interactions (MPI) and colour reconnection in HERWIG7, and are obtained from a fit to minimum-bias data collected by the CMS experiment at s=0.9, 7, and 13Te. The tunes are based on the NNPDF 3.1 next-to-next-to-leading-order parton distribution function (PDF) set for the parton shower, and either a leading-order or next-to-next-to-leading-order PDF set for the simulation of MPI and the beam remnants. Predictions utilizing the tunes are produced for event shape observables in electron-positron collisions, and for minimum-bias, inclusive jet, top quark pair, and Z and W boson events in proton-proton collisions, and are compared with data. Each of the new tunes describes the data at a reasonable level, and the tunes using a leading-order PDF for the simulation of MPI provide the best description of the dat

    Combined searches for the production of supersymmetric top quark partners in proton-proton collisions at root s=13 TeV

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    A combination of searches for top squark pair production using proton-proton collision data at a center-of-mass energy of 13 TeV at the CERN LHC, corresponding to an integrated luminosity of 137 fb(-1) collected by the CMS experiment, is presented. Signatures with at least 2 jets and large missing transverse momentum are categorized into events with 0, 1, or 2 leptons. New results for regions of parameter space where the kinematical properties of top squark pair production and top quark pair production are very similar are presented. Depending on themodel, the combined result excludes a top squarkmass up to 1325 GeV for amassless neutralino, and a neutralinomass up to 700 GeV for a top squarkmass of 1150 GeV. Top squarks with masses from 145 to 295 GeV, for neutralino masses from 0 to 100 GeV, with a mass difference between the top squark and the neutralino in a window of 30 GeV around the mass of the top quark, are excluded for the first time with CMS data. The results of theses searches are also interpreted in an alternative signal model of dark matter production via a spin-0 mediator in association with a top quark pair. Upper limits are set on the cross section for mediator particle masses of up to 420 GeV

    Measurement of electroweak WZ boson production and search for new physics in WZ + two jets events in pp collisions at √s=13TeV

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    A measurement of WZ electroweak (EW) vector boson scattering is presented. The measurement is performed in the leptonic decay modes WZ→ℓνℓ′ℓ′, where ℓ,ℓ′=e,μ. The analysis is based on a data sample of proton-proton collisions at √s=13 TeV at the LHC collected with the CMS detector and corresponding to an integrated luminosity of 35.9 fb−1. The WZ plus two jet production cross section is measured in fiducial regions with enhanced contributions from EW production and found to be consistent with standard model predictions. The EW WZ production in association with two jets is measured with an observed (expected) significance of 2.2 (2.5) standard deviations. Constraints on charged Higgs boson production and on anomalous quartic gauge couplings in terms of dimension-eight effective field theory operators are also presented

    Search for anomalous couplings in boosted WW/WZ -> l nu q(q)over-bar production in proton-proton collisions at root s=8TeV

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