16,299 research outputs found

    Rare top decay and CP violation in THDM

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    We discuss the formalism of two Higgs doublet model type III with CP violation from CP-even CP-odd mixing in the neutral Higgs bosons. The flavor changing interactions among neutral Higgs bosons and fermions are presented at tree level in this type of model. These assumptions allow the study rare top decays mediated by neutral Higgs bosons, particularly we are interested in tcl+lt\rightarrow c l^+l^-. For this process we estimated upper bounds of the branching ratios Br(tcτ+τ)\textrm{Br}(t\rightarrow c \tau^+\tau^-) of the order of 10910710^{-9}\sim 10^{-7} for a neutral Higgs boson mass of 125 GeV and tanβ=1\tan\beta=1, 1.5, 2, 2.5. For the case of tcτ+τt\rightarrow c \tau^+\tau^- the number of possible events is estimated from 1 to 10 events which could be observed in future experiments at LHC with a luminosity of 300 fb1\textrm{fb}^{-1} and 14 GeV for the energy of the center of mass. Also we estimate that the number of events for the process tcl+lt\rightarrow c l^+l^- in different scenarios is of order of 25002500.Comment: 8 pages, 5 figure

    El mercado de las aguas en Chile desde la vigencia del Codigo de Aguas de 1981 y su proyeccion con la nueva reforma

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    63 p.El objetivo de esta memoria es realizar un análisis crítico e histórico de la evolución del mercado de las aguas en Chile en los últimos 25 años a través de las distintas concepciones políticas y económicas que han regido los destinos nuestro país, centrándonos principalmente en las falencias que posee la nueva legislación de aguas, la cual impide la libre transferibilidad de los derechos de aprovechamientos del recurso hídrico, para lo cual usaremos el método analítico. Esperamos que el lector logre apreciar las debilidades que hoy presenta el mercado de las aguas en Chile y el escaso estudio por parte de los juristas y economistas a nivel nacional, que hace que tengamos una ley deficiente en cuanto a la asignación del vital elemento

    Magnetic transitions in Pr2NiO4 single crystal

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    The magnetic properties of a stoichiometric Pr2NiO4 single crystal have been examined by means of the temperature dependence of the complex ac susceptibility and the isothermal magnetization in fields up to 200 kOe at T=4.2 K. Three separate phases have been identified and their anisotropic character has been analyzed. A collinear antiferromagnetic phase appears first between TN = 325 K and Tc1 = 115 K, where the Pr ions are polarized by an internal magnetic field. At Tc1 a first modification of the magnetic structure occurs in parallel with a structural phase transition (Bmab to P42/ncm). This magnetic transition has a first‐order character and involves both the out‐of‐plane and the in‐plane spin components (magnetic modes gx and gxcyfz, respectively). A second magnetic transition having also a first‐order character is also clearly identified at Tc2 = 90 K which corresponds to a spin reorientation process (gxcyfz to cxgyaz magnetic modes). It should be noted as well that the out‐of‐phase component of χac shows a peak around 30 K which reflects the coexistence of both magnetic configurations in a wide temperature interval. Finally, two field‐induced transitions have been observed at 4.2 K when the field is directed along the c axis. We propose that the high‐field anomaly arises from a metamagnetic transition of the weak ferromagnetic component, similarly to La2CuO4

    Seminal plasma AnnexinA2 protein is a relevant biomarker for stallions which require removal of seminal plasma for sperm survival upon refrigeration

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    Some stallions yield ejaculates that do not tolerate conservation by refrigeration prior to artificial insemination (AI), showing improvement after removal of most of the seminal plasma (SP) by centrifugation. In this study, the SP-proteome of 10 different stallions was defined through high-performance liquid chromatography with tandem mass spectrometry and bioinformatic analysis in relation to the ability of the ejaculates to maintain semen quality when cooled and stored at 5°C. Stallions were classified into three groups, depending on this ability: those maintaining good quality after direct extension in a commercial extender (good), stallions requiring removal of seminal plasma (RSP) to maintain seminal quality (good-RSP), and stallions, unable to maintain good semen quality even after RSP (poor). Pathway enrichment analysis of the proteins identified in whole equine SP using human orthologs was performed using g: profiler showing enriched Reactome and the Kyoto Encyclopedia of Genes and Genomes pathways related to hexose metabolism, vesicle mediated transport, post translational modification of proteins and immune response. Specific proteins overrepresented in stallions tolerating conservation by refrigeration included a peroxiredoxin-6 like protein, and transcobalamin-2, a primary vitamin B12-binding, and transport protein. Also, the protein involved in protein glycosylation, ST3 beta-galactoside alpha-2,3-sialyltransferase 1 was present in good stallions. These proteins were nearly absent in poor stallions. Particularly, annexinA2 appeared as to be the most powerful discriminant variable for identification of stallions needing RSP prior to refrigeration, with a P = 0.002 and a q value = 0.005. Overall this is the first detailed study of the equine SP-proteome, showing the potential value of specific proteins as discriminant bio-markers for clinical classification of stallions for AI

    Wear Behavior of a Ni/Co Bilayer Coating by Physical Vapor Deposition on AISI 1045 Steel

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    Coatings by physical vapor deposition (PVD) have become highly relevant due to their wide range of applications and the rapid rate of coating formation. In this work, AISI steel 1045 was coated with two layers, Ni and Co using the PVD technique. Each coating was deposited with a thickness of 1 μm. After applying the coatings, a post-treatment was applied in an AC plasma reactor using a boron nitride blank in an Ar atmosphere at a pressure of 3 Torr, 0.3 A, and 460 V at 4, 8, and 12h. The post-treatment was characterized by optical emission spectroscopy (OES) in a range of 200-1100 nm. The main species observed by OES were Ar+, N2, N2+, and B+. The coatings on 1045 steel and posttreatment were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Also, were subjected to tribological tests to analyze wear resistance, using the Pin-on-Disk technique. The coatings on steel 1045 present remarkably better wear properties than the uncoated 1045 steel, being the sample post-treated at 4h that showed a lower wear rate
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