10,845 research outputs found

    Single top Production at sqrt(s) =7 TeV

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    The production of single top quarks occurs via three processes: t-channel, s-channel and tW associated production. The LHC experiments have observed single top production via t-channel at 7 TeV and measured its cross section, providing a measurement of |Vtb| with an uncertainty at the 10% level. Studies are in place to observe tW associated production with a sensitivity close to 3sigma and the first limits on the production cross section for s-channel are set. Other studies based on single top topologies, like flavor changing neutral currents (FCNC) are also being performed.Comment: Proceedings from the talk "Single top Production at sqrt(s)=7 TeV presented during the QCD session of the Rencontres de Moriond 2012, 4 page

    Recent CMS results in top and Higgs physics

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    After the Higgs boson discovery in 2012, the investigation of its properties and compatibility with the standard model predictions is central to the physics program of the LHC experiments. Likewise, the study of the top quark is still relevant at the LHC, more than two decades after its discovery at the Tevatron. Top quarks and Higgs bosons are produced at the LHC on a large scale and share a deep connection based on the large mass of the top quark. Both particles provide an excellent laboratory in which to search for new physics: the measurement of their properties tests the foundations of the standard model; and they feature prominently in a variety of exotic signals. The coupling of the Higgs boson to the top quark, a fundamental standard model parameter, can only be measured directly in processes where the two particles are produced together. The production of a Higgs boson together with one or two top quarks is also sensitive to several exciting new physics effects. A brief overview of the current experimental status of top quark and Higgs boson physics is presented using results from the CMS Collaboration.Comment: Updated version of the Wine & Cheese: Joint Experimental-Theoretical Physics Seminar 'Recent CMS results in top and Higgs physics' given at Fermilab, 20 November 2015. To appear in Mod. Phys. Lett.

    Discovery Potential for the SM Higgs Boson in the H -> WW* -> 2l2nu channel at LHC

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    A prospective analysis for the search of the Standard Model (SM) Higgs boson with the CMS detector is presented in the context of the early LHC data. The aim is to establish an analysis strategy for inclusive production of the Higgs boson decaying in WW* pairs in the context of the early LHC data. Higgs mass region between 120-200 GeV, in which this signature was proposed as highly sensitive, has been studied. The W decays into lnu are considered, where l stands for e or mu. The final states are characterized by two, opposite-sign, high transverse momentum leptons, missing energy, carried out by the undetected neutrinos, and little jet activity. This study uses Monte Carlo (MC) events with full detector simulation, including limited calibration and alignment precision as expected at the LHC startup. Sets of sequential cuts are applied to each of the three topologies, in order to isolate a signal which exceeds the tt and continuum WW backgrounds. Alternatively, an artificial neural network multi-variate analysis technique is used.Comment: Poster at ICHEP08, Philadelphia, USA, July 2008. 3 pages, 3 eps figure

    Effects of methamphetamine on locomotor activity and thalamic gene expression in leptin-deficient obese mice

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    Leptin is an adipose-derived hormone that regulates energy balance. Leptin receptors are expressed in extrahypothalamic sites and several reports showed that leptin can influence feeding and locomotor behavior via direct actions on dopaminergic neurons. The leptin deficient mouse (ob/ob) has been used as an animal model of blunted leptin action, and presents with obesity and mild type 2 diabetes. We used ob/ob mice to study the effect of repeated 7-day methamphetamine (METH) administration analyzing locomotion, behavioral sensitization, and somatosensory thalamic mRNA expression of voltage-gated calcium channels and glutamatergic receptors using RT-PCR. We observed reduced METH-mediated responses in ob/ob mice associated with enhanced in mRNA expression of key voltage-gated and glutamate receptors in the somatosensory thalamus. Results described here are important for understanding the control of locomotion and thalamocortical excitability by leptin.Fil: Gonzalez, Betina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Farmacológicas. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Investigaciones Farmacológicas; ArgentinaFil: Gonzalez, Candela Rocio. Universidad Maimónides. Área de Investigaciones Biomédicas y Biotecnológicas. Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y de Diagnóstico; ArgentinaFil: Bisagno, Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Farmacológicas. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Investigaciones Farmacológicas; ArgentinaFil: Urbano Suarez, Francisco Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; Argentin

    Is behavioral ecology important for understanding and predicting population dynamics?

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    Population ecology is a discipline that studies changes in the number and composition (age, sex) of the individuals that form a population. Many of the mechanisms that generate these changes are associated with individual behavior, for example how individuals defend their territories, find mates or disperse. Therefore, it is important to model population dynamics considering the potential influence of behavior on the modeled dynamics. This study illustrates the diversity of behaviors that influence population dynamics describing several methods that allow integrating behavior into population models and range from simpler models that only consider the number of individuals to complex individual-based models that capture great levels of detail. A series of examples shows the importance of explicitly considering behavior in population modeling to avoid reaching erroneous conclusions. This integration is particularly relevant for conservation, as incorrect predictions regarding the dynamics of populations of conservation interest can lead to inadequate assessment and management. Improved predictions can favor effective protection of species and better use of the limited financial and human conservation resources

    Adaptation, validation and standardization of questionnaires for graduates and employers in the State of Mexico

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    Objective is adapted, validated and standardized questionnaires one for graduates and one for employers; both questionnaires have specific data and share the income requirements. Requirements expressed in skills needed to enter the labor market. The goal is to have common denominators between the two sectors so that there is correspondence between the demand and supply of employment. Quasi-experimental design with two phases was applied; both contain cross-sectional descriptive and analytical analysis. The first phase has a 516 our graduates to perform validation of the items adaptation. The second has a 24 our companies where items are validating and standardization. The items that make up the questionnaires have concurrent validity of construct 80 % greater reliability and inter-groups was r2> 0.75 at p 0.75 en p<0.05. En términos generales, la escala total del cuestionario obtuvo una confiabilidad de α=0.833

    Slow sedimentation and deformability of charged lipid vesicles

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    The study of vesicles in suspension is important to understand the complicated dynamics exhibited by cells in vivo and in vitro. We developed a computer simulation based on the boundary-integral method to model the three dimensional gravity-driven sedimentation of charged vesicles towards a flat surface. The membrane mechanical behavior was modeled using the Helfrich Hamiltonian and near incompressibility of the membrane was enforced via a model which accounts for the thermal fluctuations of the membrane. The simulations were verified and compared to experimental data obtained using suspended vesicles labelled with a fluorescent probe, which allows visualization using fluorescence microscopy and confers the membrane with a negative surface charge. The electrostatic interaction between the vesicle and the surface was modeled using the linear Derjaguin approximation for a low ionic concentration solution. The sedimentation rate as a function of the distance of the vesicle to the surface was determined both experimentally and from the computer simulations. The gap between the vesicle and the surface, as well as the shape of the vesicle at equilibrium were also studied. It was determined that inclusion of the electrostatic interaction is fundamental to accurately predict the sedimentation rate as the vesicle approaches the surface and the size of the gap at equilibrium, we also observed that the presence of charge in the membrane increases its rigidity
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