322 research outputs found

    Using Rapidity Gaps to Distinguish Between Higgs Production by W and Gluon Fusion

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    The possibility of distinguishing between two higgs production mechanisms, W fusion and gluon fusion, is investigated using the Monte Carlo event generator PYTHIA. It is shown that, considering the designed CM energy and luminosity for the LHC, it is not possible to distinguish between the two higgs production processes as, for a given integrated luminosity, they lead to the same number of events containing a rapidity gap.Comment: uudecoded compressed tar file containing a tex file and 6 figure files. Two more figures, avaiable from the authors upon reques

    Immune response to SARS-CoV-2 variants after immunization with different vaccines in Mexico

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    There is limited information on the antibody responses against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in subjects from developing countries with populations having a high incidence of co-morbidities. Here, we analysed the immunogenicity of homologous schemes using the ChAdOx1-S, Sputnik V, or BNT162b2 vaccines and the effect of a booster dose with ChAdOx1-S in middle-aged adults who were seropositive or seronegative to the SARS-CoV-2 spike protein before vaccination. The study was conducted post-vaccination with a follow-up of 4 months for antibody titre using enzyme-linked immunosorbent assay (ELISA) and pseudovirus (PV) neutralization assays (PNAs). All three vaccines elicited a superior IgG anti-receptor-binding domain (RBD) and neutralization response against the Alpha and Delta variants when administered to individuals with a previous infection by SARS-CoV-2. The booster dose spiked the neutralization activity among individuals with and without a prior SARS-CoV-2 infection. The ChAdOx1-S vaccine induced weaker antibody responses in infection-naive subjects. A follow-up of 4 months post-vaccination showed a drop in antibody titre, with about 20% of the infection-naive and 100% of SARS-CoV-2 pre-exposed participants with detectable neutralization capacity against Alpha pseudovirus (Alpha-PV) and Delta PV (Delta-PV). Our observations support the use of different vaccines in a country with high seroprevalence at the vaccination time

    A Bayesian Approach for Estimating the Thinning Corrosion Rate of Steel Heat Exchanger in Hydrodesulfurization Plants

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    Fuel consumption has been increasing in recent years, especially that of diesel and jet fuel. For this reason, the necessity to build new plants to reduce their sulfur content has arisen. Sometimes, just revamping existing plants is feasible, but determining which pieces of equipment are in the appropriate condition to be reused is also necessary. In order to select the equipment, it is essential to have information about the wall thickness of vessels. Sometimes, the information is limited; consequently, the application of advanced statistical techniques is needed. ,e Bayesian Data Analysis (BDA) used in this study has the goal of determining a more accurate, unobserved thinning rate distribution for existing heat exchangers, taking into consideration all the information available about the thinning rate of the heat exchangers that cool down the eÔ¨Ąuent of the hydrotreating reactors in Mexican oil reÔ¨Āneries. ,e information obtained from BDA was compared with existing shell wall thickness obtaining favorable results

    Identificaci√≥n de Hongos Micorr√≠zicos en Plantaciones de Melina (Gmelina arborea Roxb) en el Tr√≥pico H√ļmedo Ecuatoriano

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    This study aimed to isolate and identify arbuscular mycorrhizal fungi in melina (Gmelina arborea Roxb) plantations. Two melina plantations of 1 and 3 years old located in the central zone of the humid Ecuadorian tropics, province of Los R√≠os, Valencia were sampled. Soil and root samples were collected in the dry season between June and December 2015. The results showed the presence of the arbuscular mycorrhizal fungi genera Glomus and Gigaspora. The genus with the greatest representativeness in quantity of spores per gram of soil was Glomus. The highest percentage of mycorrhizal colonization occurred in the roots of 1-year-old trees.El objetivo de esta investigaci√≥n fue aislar e identificar hongos formadores de micorriza arbuscular en plantaciones de melina (Gmelina arborea Roxb). Se muestrearon dos plantaciones de melina de 1 y 3 a√Īos de edad, ubicadas en la zona central del tr√≥pico h√ļmedo ecuatoriano, provincia de Los R√≠os, cant√≥n Valencia. Las muestras de suelo y ra√≠ces se recolectaron en la √©poca seca entre junio y diciembre de 2015. Los resultados mostraron la presencia de los g√©neros de hongos micorr√≠zicos arbusculares Glomus y Gigaspora. El g√©nero con mayor representatividad en cantidad de esporas por gramo de suelo fue Glomus. El mayor porcentaje de colonizaci√≥n micorr√≠zica se present√≥ en las ra√≠ces de los √°rboles de 1 a√Īo de edad

    Identification of arbuscular mycorrhizal fungi in melina (Gmelina arborea Roxb) plantations in the Ecuadorian humid tropics

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    El objetivo de esta investigaci√≥n fue aislar e identificar hongos formadores de micorriza arbuscular en plantaciones de melina (Gmelina arborea Roxb). Se muestrearon dos plantaciones de melina de 1 y 3 a√Īos de edad, ubicadas en la zona central del tr√≥pico h√ļmedo ecuatoriano, provincia de Los R√≠os, cant√≥n Valencia. Las muestras de suelo y ra√≠ces se recolectaron en la √©poca seca entre junio y diciembre de 2015. Los resultados mostraron la presencia de los g√©neros de hongos micorr√≠zicos arbusculares Glomus y Gigaspora. El g√©nero con mayor representatividad en cantidad de esporas por gramo de suelo fue Glomus. El mayor porcentaje de colonizaci√≥n micorr√≠zica se present√≥ en las ra√≠ces de los √°rboles de 1 a√Īo de edad.This study aimed to isolate and identify arbuscular mycorrhizal fungi in melina (Gmelina arborea Roxb) plantations. Two melina plantations of 1 and 3 years old located in the central zone of the humid Ecuadorian tropics, province of Los R√≠os, Valencia were sampled. Soil and root samples were collected in the dry season between June and December 2015. The results showed the presence of the arbuscular mycorrhizal fungi genera Glomus and Gigaspora. The genus with the greatest representativeness in quantity of spores per gram of soil was Glomus. The highest percentage of mycorrhizal colonization occurred in the roots of 1-year-old trees

    Técnicas para Detección y Estimación Eficiente de Potenciales Evocados

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    Los potenciales evocados (PE) en sus distintas modalidades (auditivos, visuales y somatosensoriales), se han convertido actualmente en un estudio de diagn√≥stico de patolog√≠as del sistema nervioso casi rutinario. Estos son se√Īales el√©ctricas registradas mediante electrodos en el cuero cabelludo, que se producen como respuesta de los sistemas sensoriales a la aplicaci√≥n de un est√≠mulo adecuado. Sin embargo en su adquisici√≥n, adem√°s de la respuesta evocada por el est√≠mulo, se registran potenciales generados por diversas fuentes fisiol√≥gicas y no fisiol√≥gicas; obteni√©ndose una relaci√≥n se√Īal a ruido (RSR) muy desfavorable que puede llegar a -20 dB en el caso de los potenciales evocados auditivos de tronco cerebral (PEATC).La t√©cnica com√ļnmente utilizada para mejorar la RSR, y estimar la se√Īal de PE, es la promediaci√≥n coherente o sincronizada; la cual consiste en aplicar sucesivos est√≠mulos y promediar la actividad el√©ctrica registrada en forma sincronizada con el instante de tiempo en que se aplica el est√≠mulo. Si bien la promediaci√≥n es de uso masivo, presenta limitaciones que justifican buscar alternativas a esta. Una es el tiempo requerido para lograr una estimaci√≥n confiable del PE, que dependiendo de la modalidad del mismo puede insumir m√°s o menos tiempo; en el caso de los PEATC puede ser de hasta 5 minutos. Otra es que se asume que la se√Īal de PE se mantiene constante de √©poca a √©poca y que el ruido (el resto de los potenciales) es del tipo blanco con media cero, hip√≥tesis que no es cierta para la mayor√≠a de los casos. En consecuencia el resultado obtenido de la promediaci√≥n es una mala estimaci√≥n de la se√Īal real de PE. Asimismo, hay situaciones en las que no se necesita estimar la morfolog√≠a de la se√Īal y solo basta con saber si la se√Īal est√° presente, como por ejemplo la detecci√≥n autom√°tica de hipoacusias.En este proyecto se propuso revisar, evaluar y desarrollar t√©cnicas y/o algoritmos que permitan detectar la se√Īal de PE as√≠ como tambi√©n estimar de manera m√°s eficiente que la promediaci√≥n coherent

    Phylogenetic groups and cephalosporin resistance genes of Escherichia coli from diseased food-producing animals in Japan

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    A total of 318 Escherichia coli isolates obtained from different food-producing animals affected with colibacillosis between 2001 and 2006 were subjected to phylogenetic analysis: 72 bovine isolates, 89 poultry isolates and 157 porcine isolates. Overall, the phylogenetic group A was predominant in isolates from cattle (36/72, 50%) and pigs (101/157, 64.3%) whereas groups A (44/89, 49.4%) and D (40/89, 44.9%) were predominant in isolates from poultry. In addition, group B2 was not found among diseased food-producing animals except for a poultry isolate. Thus, the phylogenetic group distribution of E. coli from diseased animals was different by animal species. Among the 318 isolates, cefazolin resistance (minimum inhibitory concentrations: ‚Č•32 őľg/ml) was found in six bovine isolates, 29 poultry isolates and three porcine isolates. Of them, 11 isolates (nine from poultry and two from cattle) produced extended spectrum ő≤-lactamase (ESBL). The two bovine isolates produced blaCTX-M-2, while the nine poultry isolates produced blaCTX-M-25 (4), blaSHV-2 (3), blaCTX-M-15 (1) and blaCTX-M-2 (1). Thus, our results showed that several types of ESBL were identified and three types of ő≤-lactamase (SHV-2, CTX-M-25 and CTX-M-15) were observed for the first time in E. coli from diseased animals in Japan
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