4,218 research outputs found

    Normalizing Weak Boson Pair Production at the Large Hadron Collider

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    The production of two weak bosons at the Large Hadron Collider will be one of the most important sources of SM backgrounds for final states with multiple leptons. In this paper we consider several quantities that can help normalize the production of weak boson pairs. Ratios of inclusive cross-sections for production of two weak bosons and Drell-Yan are investigated and the corresponding theoretical errors are evaluated. The possibility of predicting the jet veto survival probability of VV production from Drell-Yan data is also considered. Overall, the theoretical errors on all quantities remain less than 5-20%. The dependence of these quantities on the center of mass energy of the proton-proton collision is also studied.Comment: 11 pages; added references, minor text revisions, version to appear in Phys. Rev.

    Estimating turbulence kinetic energy dissipation rates in numerically simulated stratocumulus cloud-top and convective boundary layer flow: Evaluation of different methods.

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    We perform analysis of direct numerical simulation (DNS) data of two flow cases: stratocumulus cloud-top (SCT) and convective boundary layer (CBL). We test different methods for turbulence kinetic energy dissipation rate (EDR) retrieval. Among others we investigate performance of a new, iterative method, proposed recently in Wacławczyk et al. (2017), where an analytical model for energy spectra in the dissipative range is needed. We argue, the new method has some advantages over the standard spectral retrieval techniques. To apply it, only the information on the signals’ cut-off wavelength is needed and it is not necessary to define the fitting range in the inertial part of the spectrum. With this, the new method could be a basis of a general algorithm for EDR retrieval, applicable to a wide range of different atmospheric data (e.g. from commercial aircrafts). Moreover, we investigate how the presence of anisotropy due to shear, buoyancy and external intermittency in the flow affects the EDR retrieval based on the classical K41 for isotropic turbulence (Kolmogorov, 1941). © 2019 International Symposium on Turbulence and Shear Flow Phenomena, TSFP. All rights reserved

    Probing the role of point mutations in the cyp51A gene from Aspergillus fumigatus in the model yeast Saccharomyces cerevisiae

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    Azole-resistant strains of Aspergillus fumigatus have been detected and the underlying molecular mechanisms of resistance characterized. Point mutations in the cyp51A gene have been proved to be related to azole resistance in A. fumigatus clinical strains and with different resistance profiles depending on the amino acid change (G54E, G54V, G54R, G54W, M220V, M220K, M220T, M220I). The aim of this work was to express A. fumigatus cyp51A genes in the yeast Saccharomyces cerevisiae in order to better assess the contribution of each independent amino acid substitution to resistance. A tetracycline regulatable system allowing repression of the endogenous essential ERG11 gene was used. The expression of Aspergillus cyp51A alleles could efficiently restore the absence of ERG11 in S. cerevisiae. In general, S. cerevisiae clones expressing. A. fumigatus cyp51A alleles from azole-resistant isolates showed higher MICs to all azoles tested than those expressing alleles from susceptible isolates. The azole susceptibility profiles obtained in S. cerevisiae upon expression of specific cyp51A alleles recapitulated susceptibility profiles observed from their A. fumigatus origins. In conclusion this work supports the concept that characteristics of specific A. fumigatus cyp51A alleles could be investigated in the heterologous host S. cerevisia

    Heartworm Disease (Dirofilaria immitis) and Their Vectors in Europe – New Distribution Trends

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    Cardiopulmonary dirofilariasis is a cosmopolitan disease caused by Dirofilaria immitis, which affects mainly canids and felids. Moreover, it causes zoonotic infections, producing pulmonary dirofilariasis in humans. Heartworm disease is a vector-borne transmitted disease, thus transmission depends on the presence of competent mosquito species, which is directly related to favorable climate conditions for its development and survival. Cardiopulmonary dirofilariasis is mainly located in countries with temperate and tropical climates. Europe is one of the continents where animal dirofilariasis has been studied more extensively. In this article we review the current prevalence of canine and feline cardiopulmonary dirofilariasis in the European continent, the transmission vectors, the current changes in the distribution and the possible causes, though the analysis of the epidemiological studies carried out until 2001 and between 2002 and 2011. The highest prevalences have been observed in the southern European countries, which are considered historically endemic/hyperendemic countries. Studies carried out in the last 10 years suggest an expansion of cardiopulmonary dirofilariasis in dogs toward central and northern Europe. Several factors can exert an influence on the spreading of the disease, such as movement of infected animals, the introduction of new species of mosquitoes able to act as vectors, the climate change caused by the global warming, and development of human activity in new areas. Veterinary controls to prevent the spreading of this disease, programs of control of vectors, and adequate protocols of prevention of dirofilariasis in the susceptible species should be carried out

    EL TRUEQUE COMO ALTERNATIVA DE REARTICULACION SOCIAL DE LOS DESOCUPADOS EN EL MARCO DEL MERCOSUR. EL CASO ARGENTINO

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    Los procesos socioeconómicos y políticos mundiales del fin de siglo XX configuran el marco para una creciente interdependencia y globalización del sistema internacional con consecuencias sobre las sociedades, en términos de transmutaciones socio-políticas y económicas que influyen tanto en las relaciones y actores sociales como en el Estado mismo. De manera simultánea, se consolida, durante los últimos veinte años, un patrón de crecimiento económico generador de profundas desigualdades sociales y de exclusión de vastos sectores de la población.La precarización laboral, subocupación y desocupación aparecen como algunas de las manifestaciones palpables de esas transformaciones con efecto traumático sobre la identidad del sujeto, que se sostienen a partir de una crisis social que por su agravamiento muta en un problema de salud colectiva, por la exclusión y expulsión de un sistema productivo que desafilia socialmente a los sujetos de su utilidad pública –como gestores de bienes y servicios-, de su inserción en el consumo, familiar y grupal, a la vez que lo afecta en su ciudadanía como sujeto de derechos civiles, políticos y sociales. Estas consideraciones nos permiten interrogarnos si el sufrimiento psíquico del empleado precario y del desempleado es un nuevo instrumento en la etapa actual del capitalismo que permite obtener mayor cantidad de mano de obra a disposición, en condiciones de explotació

    Vaccination programs, parity, and calving season as factors affecting the risk of fetal losses and mummified fetuses in Holstein cows

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    Aim of the study: To investigate vaccination programs, parity, and calving season as factors affecting the risk of abortion and mummified fetuses in Holstein cows.Area of study: Hot zone of Northeast Mexico.Material and methods: Multiple logistic regression models were used to examine the relationship between peripartum disorders, parity, previous occurrence of abortion, season of calving, vaccination program, incidence of abortion, and mummified fetuses in Holstein cows.Main results: For 7014 pregnancies (2886 cows), the percentage of cows aborting and having mummified fetuses was 17.7% and 1.1%, respectively. As the number of brucellosis vaccinations increased, the incidence of abortion increased (10.4% for a single vaccination and 38.0% for 6 accumulated vaccinations). Abortion for cows having 1-2 previous abortions (56%) and >2 abortions (77%) was fivefold and sevenfold greater (p<0.01), respectively, than that for cows without previous abortion. Other important risk factors for abortion were number of calvings (19.8% for nulliparous and primiparous vs. 13.8% for >3 parturitions; OR=1.7, p<0.01), leptospirosis vaccine application <55 days postpartum (dpp; OR=1.3, p<0.05), viral vaccine application >37 dpp (OR=1.3, p<0.01), brucellosis vaccine application >20 dpp (OR=1.6, p<0.01), and no application of clostridial vaccine (OR=3.7, p<0.01). Significant risk factors for mummified fetuses were application of ≥3 brucellosis vaccinations (OR=3.3, p<0.01), no application of 10-way clostridial vaccine (OR=2.3, p<0.01), >2 previous abortions (OR=18.4, p<0.01), and calving in autumn (OR=0.4, compared to winter, p<0.05).Research highlights: Risk of abortion and mummified fetuses in Holstein cows has been found to be related to vaccination programs

    Modelo de elementos finitos de la columna lumbar

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    En este trabajo se describe un modelo de Elementos Finitos de la columna lumbar humana. El objetivo buscado es la utilización del mismo como herramienta de investigación aplicada a la cirugía ortopédica de columna lumbar. Para conseguir este objetivo se ha elaborado un modelo no lineal y paramétrico de la columna lumbar completa, el cual puede modificarse con facilidad tanto en su geometría como en sus características mecánicas de modo que puedan reflejarse tanto distintas alteraciones segmentarias como diversas técnicas de fijación. También se expone la contrastación del modelo, realizada a partir de resultados experimentales recogidos de la literatura sobre el tema.Peer Reviewe

    The effects of periparturient events, mastitis, lameness and ketosis on reproductive performance of Holstein cows in a hot environment

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    The aim of this study was to determine the association among periparturient events such as mastitis, lameness (infectious and non-infectious) and ketosis and the reproductive performance of high producing Holstein cows in a hot environment. The health status and reproductive data variables were recorded from 6,566 completed lactations in a large dairy operation. A logistic regression model with the stepwise procedure was used, considering the occurrence of the health problems during the pre-breeding period as fixed effect risk factors and reproductive variables as dependent variables. Pregnancy rate of cows contracting clinical mastitis (CM) around the period of first inseminations was five percentage points lower than cows without this disease. Cows with CM shortly before or after the first service had twice the risk of requiring more than three services per pregnancy than cows with healthy udders. Cows experiencing abortion, laminitis or metritis were two times more likely to require >3 services per pregnancy than cows not experiencing these reproductive disorders. Cows experiencing lameness, mastitis and metritis presented a significantly longer interval between calving and pregnancy compared to healthy cows. Ketosis and lameness increased the odds of a cow of being inseminated for the first time after 70 days in milk. In conclusion, these results suggest that abortion, ketosis, CM, retained placenta (RP), metritis, and lameness are associated with decreased reproductive performance in high producing Holstein cows subjected to thermal stress

    Métricas para la medición de las competencias generales y específicas para el Grado en Ingeniería Informática

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    El proceso de elaboración de las memorias de grado se ha basado en un conjunto de competencias generales y específicas que, en la mayoría de los casos, entrañan un alto nivel de abstracción y ambigüedad. Por otro lado, la aparición de las competencias no ha ayudado a los alumnos a entender mejor en qué medida alcanzan los objetivos de las diferentes asignaturas, ni a tomar mejores decisiones sobre los pasos a seguir en su carrera profesional. En este artículo se pretende mostrar los resultados obtenidos durante la investigación realizada, que ha tenido como objetivo desgranar las competencias generales y específicas del Grado en Ingeniería Informática, de modo que se ofrezca un acercamiento mucho más concreto y detallado con las asignaturas y, consecuentemente, que pueda justificarse adecuadamente la forma en que las asignaturas permiten alcanzar parcial o completamente las competencias para el grado. Este enfoque, y su orientación a obtener métricas sobre las que valorar el grado en que se han alcanzado los objetivos, también permitirá que los alumnos puedan tomar mejores decisiones a la hora de seleccionar las diferentes asignaturas del grado y conocer para qué competencias están mejor cualificados.SUMMARY -- The process of writing honours theses is based on a set of general and specific competences which, in the majority of cases, entail a high level of abstraction and ambiguity. What is more, the apparition of these competences has not helped students towards a better understanding of the extent to which they attain the objectives of their various subjects, or to make better decisions as regards the steps to follow in their professional careers. The intention of this paper is to show the results obtained during research whose objective was to separate the general and specific competences involved in the Computer Engineering Degree in order to provide a much more concrete and detailed approach to the subjects, which will consequently allow the way in which the subjects permit the partial or total attainment of the competences for the degree to be justified. This approach, and its orientation towards obtaining metrics with which to evaluate the degree to which the objectives have been attained, will also allow students to make better decisions when selecting various degree subjects and to discover for which competences they are best qualified.Peer Reviewe

    Effects of organic acid salts on ruminal biogas production and fermentation kinetics of total mixed rations with different maize silage to concentrate ratios

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    Methane is a major greenhouse gas (GHG) produced during the normal digestive process in ruminant animals (Blaxter and Clapperton, 1965) with a global warming potential, 25-fold that of carbon dioxide (IPCC, 2007). In addition to environmental implications, ruminant methanogenesis represents a loss of 2e12% of the gross energy intake (Johnson and Johnson, 1995; Soltanali et al., 2015) with a greater environmental impact from the confinement system compared with pasture-based system (O'Brien et al., 2012). A cow can produce 250 to 500 L of methane (CH4) per day depending on the quantity and quality of the feed which affects rate of digestion and rate of passage in the fermentation process (Johnson and Johnson, 1995). Furthermore, cattle consuming high fibre diets typically lose about 6% of gross dietary energy as methane (CH4), whereas those on high concentrate rations generally lose about 3% of dietary gross energy as CH4 (Mc Geough et al., 2012). According to the Food and Agriculture Organization of the United Nations, the livestock sector is responsible for about 18% of total global anthropogenic GHG emissionsRuminants are one of the major generators of methane, a greenhouse gas (GHG) with a global warming potential, 25-fold that of carbon dioxide. Methane production by ruminants also reduces the gross feed energy intake utilization by about 2e12%. The present study aimed to test the effects of different levels of a ruminal fermentation modulator (RFM) on in vitro ruminal fermentation and GHG production of five total mixed rations (TMR) with different silage (S) to-concentrate (C) ratios (0S:100C, 25S:75C, 50S:50C, 75S:25C, and 100S:0C). The RFM contained mainly calcium propionate and malate, and monopropylene glycol. The rumen inoculum was collected from a Brown Swiss cow fed a TMR of concentrate and alfalfa hay (1:1 dry matter (DM)) ad libitum. Gas production (GP) measurements were recorded up to 72 h of incubation. There were interactions (P 0.05) on methane production. The DM digestibility increased (linear effect; P ¼ 0.003) as silage level increased. Overall, increasing silage in the TMR lowered the asymptotic GP and DM digestibility. The asymptotic GP was higher with the addition of the RFM without any effect on fermentation kinetics. These results suggest that the RFM can be used as an environmental cleaner product in animal farming due to its ability to improve ruminal fermentation of feedstuffs and to reduce methane emission
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