36 research outputs found
Tipificación de unidades de producción de ganado bovino en Tejupilco, Estado de México
No full textSE TIPIFICARON UP DE GANADO BOVINO EN EL MUNICIPIO DE TEJUPILCO, ESTADO DE MÉXICO, CONSIDERANDO VARIABLES TÉCNICO ECONÓMICAS, CON INFORMACIÓN DE 50 GANADEROS. SE OBSERVÓ GRAN DIVERSIDAD DE UPs CON CARACTERÍSTICAS INTERNAS PROPIAS QUE DEFINEN SU ESTRUCTURA Y FUNCIONAMIENTO
CAMBIOS EN LA GANADERÍA DOBLE PROPÓSITO EN EL TRÓPICO SECO DEL ESTADO DE MÉXICO
No full text"Resumen La ganadería es una actividad económica importante en zonas rurales, aunque en años recientes ha presentado cambios importantes, debido a ajustes socioeconómicos. Uno de estos cambios es criar ganado para cumplir dos metas de producción en luga
Cambios en la ganadería doble propósito en el trópico seco del Estado de México
Get PDFLa ganadería es una actividad económica importante en zonas rurales, aunque en años recientes ha presentado cambios importantes, debido a ajustes socioeconómicos. Uno de estos cambios es criar ganado para cumplir dos metas de producción en lugar de una. El objetivo de este estudio fue analizar los cambios en unidades de producción (UP) con ganado doble propósito (DP) en el sur del Estado de México. Mediante seguimientos técnico-económicos, en 2006 se obtuvo información de 50 ganaderos elegidos con muestreo aleatorio. Las variables evaluadas fueron 14 de estructura y manejo (abandono de la actividad ganadera, disponibilidad de mano de obra, alimentación, superficie y tamaño de hato) y 14 económicas obtenidas con encuestas estructuradas. Todos los ganaderos aportaron información confiable para validar los datos que fueron contrastados con los registros en la UP y con informantes clave y estadísticas oficiales para las variables económicas. Las mismas variables se evaluaron en la misma muestra en 2013. El método estadístico usado fue una prueba t de Student para la comparación de valores promedio de las 28 variables entre las fechas. Durante el periodo de siete años 56 % de los ganaderos abandonaron la actividad y la mano de obra disminuyó 42 % (p0.05). La superficie y el tamaño del hato se mantuvo (p0.05). Los cambios en la alimentación y en el ingreso total por vaca y superficie (ha) fueron significativos (p0.05). Las UP DP cambiaron su estructura, el uso de la tierra, la alimentación, el manejo y la gestión de las UP y, por tanto, la organización y orientación de la producción del ganado. La tendencia indica que los cambios en la ganadería del sur del Estado de México continuarán
La ganadería en condiciones de trópico seco. El caso del sur del Estado de México. Condiciones actuales y perspectivas de desarrollo
No full textEn esta obra, se abordan aspectos relevantes de Unidades de Producción doble propósito del trópico seco del sur del Estado de México, realizadas por investigadores de un Cuerpo Académico del CU UAEM Temascaltepec, producto de experiencias en investigación. El objetivo es proporcionar información para conocer la situación actual de la ganadería del trópico seco del sur de la entidad meciquense
Machine learning method for enforcing variable independence in background estimation with LHC data: ABCDisCoTEC
No full textA novel solution is presented for the problem of estimating the backgrounds of a signal search using observed data while simultaneously maximizing the sensitivity of the search to the signal. The ``ABCD method'' provides a reliable framework for background estimation by partitioning events into one signal-enhanced region (A) and three background-enhanced control regions (B, C, and D) via two statistically independent variables. In practice, even slight correlations between the two variables can significantly undermine the method's performance. Thus, choosing appropriate variables by hand can present a formidable challenge, especially when background and signal differ only subtly. To address this issue, the ABCD with distance correlation (ABCDisCo) method was developed to construct two artificial variables from the output scores of a neural network trained to maximize signal-background discrimination while minimizing correlations using the distance correlation measure. However, relying solely on minimizing the distance correlation can yield undesirable characteristics in the resulting distributions, which may compromise the validity of the background prediction obtained using this method. The ABCDisCo training enhanced with closure (ABCDisCoTEC) method is introduced to solve this issue by directly minimizing the nonclosure, expressed as a dedicated differentiable loss term. This extended method is applied to a data set of proton-proton collisions at a center-of-mass energy of 13 TeV recorded by the CMS detector at the CERN LHC. Additionally, given the complexity of the minimization problem with constraints on multiple loss terms, the modified differential method of multipliers is applied and shown to greatly improve the stability and robustness of the ABCDisCoTEC method, compared to grid search hyperparameter optimization procedures
Search for charged lepton flavor violating Z and Z' boson decays in proton-proton collisions at = 13 TeV
No full textA search for flavor violating decays of the Z boson to charged leptons is performed using data from proton-proton collisions at = 13 TeV collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 138 fb. Each of the decays Z e, Z e, and Z is considered. The data are consistent with the backgrounds expected from standard model processes. For the Z e channel the observed (expected) 95% confidence level upper limit on the branching fraction is 1.9 (2.0) 10, which is the most stringent direct limit to date on this process; the corresponding limits for the Z e and Z channels are 13.8 (11.4) 10 and 12.0 (5.3) 10, respectively. Additionally, the e final state is used to search for lepton flavor violating decays of Z' resonances in the mass range from 110 to 500 GeV. No significant excess is observed above the predicted background levels
Search for heavy pseudoscalar and scalar bosons decaying to a top quark pair in proton-proton collisions at = 13 TeV
No full textA search for pseudoscalar or scalar bosons decaying to a top quark pair () in final states with one or two charged leptons is presented. The analyzed proton-proton collision data was recorded at = 13 TeV by the CMS experiment at the CERN LHC and corresponds to an integrated luminosity of 138 fb. The invariant mass of the reconstructed system and variables sensitive to its spin and parity are used to discriminate against the standard model background. Interference between pseudoscalar or scalar boson production and the standard model continuum is included, leading to peak-dip structures in the distribution. An excess of the data above the background prediction, based on perturbative quantum chromodynamics (QCD) calculations, is observed near the kinematic production threshold, while good agreement is found for high . The data are consistent with the background prediction if the contribution from the production of a color-singlet quasi-bound state , predicted by nonrelativistic QCD, is added. Upper limits at 95% confidence level are set on the coupling between the pseudoscalar or scalar bosons and the top quark for boson masses in the range 3651000 GeV, relative widths between 0.5 and 25%, and two background scenarios with or without contribution
First exclusive reconstruction of the B, B, and B mesons and precise measurement of their masses
No full textUsing proton-proton collision data collected by the CMS experiment at = 13 TeV in 20162018, corresponding to an integrated luminosity of 140 fb, the first full reconstruction of the three vector B meson states, B, B, and B, is performed. The mass differences between the excited mesons and their corresponding ground states are measured to be = 45.277 0.039 0.027 MeV, = 45.471 0.056 0.028 MeV, and = 49.407 0.132 0.041 MeV, where the first uncertainties are statistical and the second are systematic. These results improve on the precision of previous measurements by an order of magnitude
Search for light pseudoscalar bosons, pair-produced in Higgs boson decays in the four-electron final state in proton-proton collisions at = 13 TeV
No full textA search for pairs of light neutral pseudoscalar bosons (A) resulting from the decay of a Higgs boson is performed. The search is conducted using LHC proton-proton collision data at = 13 TeV, collected with the CMS detector in 20162018 and corresponding to an integrated luminosity of 138 fb. The A boson decays into a highly collimated electron-positron pair. A novel multivariate algorithm using tracks and calorimeter information is developed to identify these distinctive signatures, and events are selected with two such merged electron-positron pairs. No significant excess above the standard model background predictions is observed. Upper limits on the branching fraction for H AA 4e are set at 95% confidence level, for masses between 10 and 100 MeV and proper decay lengths below 100 m, reaching branching fraction sensitivities as low as 10. This is the first search for Higgs boson decays to four electrons via light pseudoscalars at the LHC. It significantly improves the experimental sensitivity to axion-like particles with masses below 100 MeV
