463 research outputs found
Using Rapidity Gaps to Distinguish Between Higgs Production by W and Gluon Fusion
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
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
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 effluent of the hydrotreating reactors in Mexican oil refineries. ,e information obtained from BDA was compared with existing shell wall thickness obtaining favorable results
Identificación de Hongos Micorrízicos en Plantaciones de Melina (Gmelina arborea Roxb) en el Trópico Húmedo Ecuatoriano
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 Ríos, 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 investigación 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 años de edad, ubicadas en la zona central del trópico húmedo ecuatoriano, provincia de Los Ríos, cantón Valencia. Las muestras de suelo y raíces se recolectaron en la época seca entre junio y diciembre de 2015. Los resultados mostraron la presencia de los géneros de hongos micorrízicos arbusculares Glomus y Gigaspora. El género con mayor representatividad en cantidad de esporas por gramo de suelo fue Glomus. El mayor porcentaje de colonización micorrízica se presentó en las raíces de los árboles de 1 año de edad
Identification of arbuscular mycorrhizal fungi in melina (Gmelina arborea Roxb) plantations in the Ecuadorian humid tropics
El objetivo de esta investigación 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 años de edad, ubicadas en la zona central del trópico húmedo ecuatoriano, provincia de Los Ríos, cantón Valencia. Las muestras de suelo y raíces se recolectaron en la época seca entre junio y diciembre de 2015. Los resultados mostraron la presencia de los géneros de hongos micorrízicos arbusculares Glomus y Gigaspora. El género con mayor representatividad en cantidad de esporas por gramo de suelo fue Glomus. El mayor porcentaje de colonización micorrízica se presentó en las raíces de los árboles de 1 año 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 Ríos, 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
Measurement of the cosmic ray spectrum above eV using inclined events detected with the Pierre Auger Observatory
A measurement of the cosmic-ray spectrum for energies exceeding
eV is presented, which is based on the analysis of showers
with zenith angles greater than detected with the Pierre Auger
Observatory between 1 January 2004 and 31 December 2013. The measured spectrum
confirms a flux suppression at the highest energies. Above
eV, the "ankle", the flux can be described by a power law with
index followed by
a smooth suppression region. For the energy () at which the
spectral flux has fallen to one-half of its extrapolated value in the absence
of suppression, we find
eV.Comment: Replaced with published version. Added journal reference and DO
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