382 research outputs found

    Monte Carlo simulation for radiative kaon decays

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    For high precision measurements of K decays, the presence of radiated photons cannot be neglected. The Monte Carlo simulations must include the radiative corrections in order to compute the correct event counting and efficiency calculations. In this paper we briefly describe a method for simulating such decays.Comment: 11 pages, 1 figur

    Positivity Constraints for Spin-Dependent Parton Distributions

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    We derive new positivity constraints on the spin-dependent structure functions of the nucleon. These model independent results reduce conside\-rably their domain of allowed values, in particular for the chiral-odd parton distribution h1(x)h_1 (x).Comment: 8 pages,CPT-94/P.3059,LaTex,3 fig available on cpt.univ-mrs.fr directory pub/preprints/94/fundamental-interactions/94-P.305

    Human sperm subpopulations: relationship between functional quality and protein tyrosine phosphorylation

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    Human semen is composed of a heterogeneous population of sperm with varying degrees of structural and functional differentiation and normality, which result in subpopulations of different quality. Using a discontinuous Percoll gradient, we separated three subsets of sperm [(45%; L45), (65%; L65) and (90%; L90) fractions] from normozoospermic human semen samples from healthy donors and proceeded to characterize their morphology, motility and hyperactivation, as well as their ability to undergo tyrosine phosphorylation under capacitating conditions.Fil: Buffone, Mariano Gabriel. Laboratorio de Estudios en Reproducción; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Doncel, G. F.. Eastern Virginia Medical School; Estados UnidosFil: Marin Briggiler, Clara Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Vazquez, Monica Hebe. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Calamera, J. C.. Laboratorio de Estudios en Reproducción; Argentin

    Radiative Corrections to K^0_{l3} Decays

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    We calculate the long-distance radiative corrections \delta^e_{LD} and \delta^{\mu}_{LD} to the K^0 -> \pi^- e^+ \nu_e and the K^0 -> pi^- \mu^+ \nu_{\mu} decay rates. This analysis includes contributions to the long-distance radiative corrections from outside the kinematically-allowed three-body Dalitz region and tests the sensitivity of the radiative corrections to the hadronic K-pi form factors. A program, KLOR, was written to numerically evaluate the radiative corrections and to generate Monte Carlo events for experimental acceptance studies. The K^0_{e3} and the K^0_{\mu 3} long-distance radiative correction parameters are determined to be (1.3 +/- 0.3)% and (1.9 +/- 0.3)%, respectively. We also present predictions for the fraction of radiative K^0_{l3} events satisfying various requirements on final-state photon kinematics.Comment: Accepted in Annals of Physics; 16 pages, 8 figures; v3 contains minor text change

    Actividad in vitro de bacterias endófitas promotoras de crecimiento asociadas con pasto colosoana en el municipio de Corozal, Sucre

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    The objective of study was evaluated in vitro binding activity of nitrogen and phosphate bacteria endophytic solubilizated isolated from different tissues of colosoana grass in the districts of the municipality of Corozal, Sucre Department. Collected sample of roots stems and leaves of colosoana pasture from different farms. Of each tissue previously disinfected is made isolation in the middle of cultivation of bacteria endophytic, to which is les determined it density population of bacteria endophytic by means of count in UFC / g of tissue and is carried out separation of morphs by shape, color, size and appearance in media of crops. Each isolated morphotype was evaluated in vitro binding activity of nitrogen and phosphate solubilizing specific crops media. Are observed differences significant for density population of bacteria with respect to tissue, with higher values in root (1x1011 g/ root), followed of the stem (1.82x1010 g/stem) and with leaf density sheets (1.15x1010 g/leaf). The results of the identification kit API20E confirmed the presence of bacteria endophytes Pseudomonas aeruginosa and Stenotrophomonas maltophilia with ability to fix nitrogen and solubilize phosphates.El presente estudio tuvo como objetivo evaluar in vitro la actividad fijadora de nitrógeno y solubilizadora de fosfato de bacterias endófitas aisladas de diferentes de tejidos de pasto colosoana en los corregimientos del municipio de Corozal, departamento de Sucre. Se colectaron muestra de raíz, tallos y hojas de pasto colosoana. De cada tejido previamente desinfectado se realizó aislamiento en medio de cultivo para bacterias endófitas, a las cuales se les determinó la densidad poblacional por medio de conteo en UFC/ g de tejido y se separación de morfotipos por forma, color, tamaño y apariencia en medios de cultivos. A Cada morfotipo aislado se le evaluó in vitro su actividad fijadora de nitrógeno y solubilizadora de fosfato en medios de cultivos específicos. Se observaron diferencias significativas para densidad poblacional de bacterias con respecto a tejido, con mayores valores en raíz (1x1011 g/ raíz), seguida del tallo (1.82x1010 g/tallo) y menor densidad en hojas (1.15x1010 g/hoja). Los resultados de la identificación con kit API20E confirmaron la presencia de las bacterias endófitas Pseudomona aeuroginosa y Stenotrophomonas maltophilia con capacidad de fijar nitrógeno y solubilizar fosfatos

    Bridging the Gap between Preclinical and Clinical Microbicide Trials: Blind Evaluation of Candidate Gels in Murine Models of Efficacy and Safety

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    Despite significant protection in preclinical studies, cellulose sulfate (CS) failed to protect women against HIV-1/2 and was associated with a trend toward increased HIV-1 acquisition in one of the clinical trials. These results highlight the need for preclinical tests more predictive of clinical outcomes. The objective of this study was to test coded vaginal gels, including CS, in murine models of safety and efficacy to determine the models' utility for evaluating future products.Four coded formulations, including 6% CS, 2% PRO 2000 and two placebo gels, were administered intravaginally to medroxyprogesterone-treated mice and their ability to prevent genital herpes (efficacy) or to alter the susceptibility to low dose HSV challenge (safety) was determined. Nonoyxnol-9 served as a positive toxicity control.CS and PRO 2000 significantly protected mice from genital herpes following infection with a laboratory or clinical isolate of HSV-2 introduced in buffer (p<0.001). However, protection was reduced when virus was introduced in seminal plasma. Moreover, mice were significantly more susceptible to infection with low doses of HSV-2 when challenged 12 h after the 7th daily dose of CS or nonoxynol-9 (p<0.05). The increased susceptibility was associated with alterations in epithelial architecture.CS prevented genital herpes when present at the time of viral challenge, but increased the rate of infection when gel was applied daily for 7 days with a vaginal wash prior to viral inoculation. The findings presumably reflect altered epithelial architecture, which may have contributed to the trend towards increased HIV observed clinically

    Biological and technical variables affecting immunoassay recovery of cytokines from human serum and simulated vaginal fluid: A multicenter study

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    The increase of proinflammatory cytokines in vaginal secretions may serve as a surrogate marker of unwanted inflammatory reaction to microbicide products topically applied for the prevention of sexually transmitted diseases, including HIV-1. Interleukin (IL)-1β and IL-6 have been proposed as indicators of inflammation and increased risk of HIV-1 transmission; however, the lack of information regarding detection platforms optimal for vaginal fluids and interlaboratory variation limit their use for microbicide evaluation and other clinical applications. This study examines fluid matrix variants relevant to vaginal sampling techniques and proposes a model for interlaboratory comparisons across current cytokine detection technologies. IL-1β and IL-6 standards were measured by 12 laboratories in four countries, using 14 immunoassays and four detection platforms based on absorbance, chemiluminescence, electrochemiluminescence, and fluorescence. International reference preparations of cytokines with defined biological activity were spiked into (1) a defined medium simulating the composition of human vaginal fluid at pH 4.5 and 7.2, (2) physiologic salt solutions (phosphate-buffered saline and saline) commonly used for vaginal lavage sampling in clinical studies of cytokines, and (3) human blood serum. Assays were assessed for reproducibility, linearity, accuracy, and significantly detectable fold difference in cytokine level. Factors with significant impact on cytokine recovery were determined by Kruskal−Wallis analysis of variance with Dunn’s multiple comparison test and multiple regression models. All assays showed acceptable intra-assay reproducibility; however, most were associated with significant interlaboratory variation. The smallest reliably detectable cytokine differences (P < 0.05) derived from pooled interlaboratory data varied from 1.5- to 26-fold depending on assay, cytokine, and matrix type. IL-6 but not IL-1β determinations were lower in both saline and phosphate-buffered saline as compared to vaginal fluid matrix, with no significant effect of pH. The (electro)chemiluminescence-based assays were most discriminative and consistently detected <2-fold differences within each matrix type. The Luminex-based assays were less discriminative with lower reproducibility between laboratories. These results suggest the need for uniform vaginal sampling techniques and a better understanding of immunoassay platform differences and cross-validation before the biological significance of cytokine variations can be validated in clinical trials. This investigation provides the first standardized analytic approach for assessing differences in mucosal cytokine levels and may improve strategies for monitoring immune responses at the vaginal mucosal interface

    A Study of the Radiative Ke3 Decay and Search for Direct Photon Emission with the KLOE Detector

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    We present a measurement of the ratio R = \Gamma(\keg;\Estar>30\mev,\qstar>20^\circ)//\Gamma(\kegf)andafirstmeasurementofthedirectemissioncontributioninKLsemileptonicdecays.ThemeasurementisdoneattheDAFNEphi−factoryselectingphi−>KLKSdecayswiththeKLOEdetector.Weuse328pb−1 and a first measurement of the direct emission contribution in KL semileptonic decays. The measurement is done at the DAFNE phi-factory selecting phi->KL KS decays with the KLOE detector. We use 328 pb^{-1} of data corresponding to about 3.5 million Ke3(g) events and about 9000 radiative events. Our result is R=(924 +/- 23(stat) +/-16(syst)10^{-5} for the branching ratio and X=-2.3 +/- 1.3(stat) +/- 1.4(syst) for the parameter describing direct emission.Comment: 8 pages, 7 figure

    Lynx: A knowledge-based AI service platform for content processing, enrichment and analysis for the legal domain

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    The EU-funded project Lynx focuses on the creation of a knowledge graph for the legal domain (Legal Knowledge Graph, LKG) and its use for the semantic processing, analysis and enrichment of documents from the legal domain. This article describes the use cases covered in the project, the entire developed platform and the semantic analysis services that operate on the documents. © 202

    A New Measurement of the Radiative Ke3 Branching Ratio and Photon Spectrum

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    We present a preliminary report on a new measurement of the radiative neutral Ke3 branching ratio and the first study of the photon spectrum in this decay. We find BR(Ke3g, E*_g>30 GeV, Th*_eg>20 deg)/BR(Ke3) = 0.911+-0.009(stat)+0.021-0.010(syst)%. Our measurement of the spectrum is consistent with inner bremsstrahlung only as the source of photons at the 2 sigma level.Comment: 5 pages, 4 figures, proceedings paper from Meson 2000, Cracow, Poland, May 200
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