Plant Biomass and Bovine Live Weight Changes in Mono-Specific and Mixed Pastures during the Rainy Season in Dry Tropical Mexico

Dry tropics suffer long drought periods each year, negatively affecting the amount and digestibility of forage for cattle production. The aim of this study was evaluate different pasture types, grazed by cattle during the rainy season. Three hectares were prepared to compare: grass monoculture, Andropogon gayanus (G); a grass-legume mixture of A. gayanus and Clitoria ternatea (GL), and a grass-legume-tree mixture of A. gayanus, C. ternatea and Morus alba (GLT). Two grazing cycles (4 d grazing followed by 32 d resting; 72 d total) were completed. Three heifers (average initial weight 192 kg) grazed each experimental unit. The amounts of forage offered, remaining after grazing, and removed by animals differed significantly among the pasture treatments. Total forage offered by period was 2007, 4089, and 4192 DM kg/ha for G, GL, and GLT, respectively. Total residual forage was 1074, 1878 and 2613 DM kg/ha respectively, while total forage removed was 934, 2209, and 1579 DM kg/ha, respectively. Differences for offered forage were detected only for residual and consumed forage for GL prairies. Differences in available forage were mainly due to differences in the amount of stem and live material. Daily weight gain was 0.138, 0.504 and 0.501 kg per animal for G, GL, and GLT, respectively. Mixed pasture treatments yielded better live weight gain due to the better quality of available forage

Forage Biomass and Bovine Live Weight Changes within Monospecific and Mixed Prairies over the Dry Season in Tropical México

In the tropical systems of cattle grazing, the limited period of forage production and low forage protein content and digestibility of the same, are the main constraints to increasing live weight gain. Grass-legume pasture improves forage quantity and quality and sowing mixed swards in both the wet and dry tropics is now common practice. However, much less is known if inclusion of a fodder tree as a third component could further improve forage parameters. The aim of this study was to evaluate three types of grasslands, grazed by cattle in the dry season of the dry tropics. Swards were established to compare: grass only (PP), grass-legume (PA) and silvo-pastoral (PSP) pastures on basis of forage on-offer, residual and disappeared and bullock’s daily live-weight gain. Species used were: Andropogon gayanus Kunth, Clitoria ternatea Linn and Morus alba Linn

Nutritional Sensitivity Per Morphological Component in \u3ci\u3eUrochloa\u3c/i\u3e Hybrid under Tropical Environments

Camello® (GP 3025) is a tolerant to drought Urochloa hybrid grass showing good forage production, early flowering with high regrowth rates. The objective was to define nutrient concentration changes by morphological component and, their differences for two tropical contrasting environments. Nutrient concentrations differences (P≤0.05) were observed among morphological components over time. In environments (Aw1) the morphological components showed higher average protein content in comparison to that from hostile conditions (Aw0); lamina (12.2% vs 10.4%), pseudostem (9.5% vs 6.6%) and sheath (9.8% vs 6.8%). Hostile environments (Aw0) promoted increases for FAD (47.9%, 46.9%, pseudostem and sheath, respectively) and lignin (6.6%, 9.1% pseudostem and sheath, respectively). The nutritional changes per morphological components is the best tool to define optimal moment for harvesting on nutritional bioavailability for livestock production intensification

Effect of Grazing Management on Herbage Accumulation of Lucerne-Orchard Grass Sward

Throughout most of México, lucerne (Medicago sativa) is the primary forage legume used in the dairy industry. Unfortunately, lucerne does not grow in late autumn and winter due to adverse weather. Recent studies with lucerne have suggested that the inclusion of a companion grass will invariably increase the seasonal distribution and total annual yield of swards (Laidlaw & Teuber, 2001). However the management of mixed swards containing lucerne is difficult as a grazing frequency or intensity which suits one species may be detrimental to the other. Changes in balance between grass and legume, especially in grazed swards, have been observed. In México mixtures of lucerne-orchard grass have a good persistence and productivity. However the explanation for this is unclear. This study examined the effects of different grazing management practices on lucerne-orchard grass production and seasonal distribution

Evaluación de la distancia entre plantas sobre el rendimiento y calidad de semilla de Brachiaria brizantha

The objective was evaluating the effect of plant spacing on seed yield and quality in Bracchiaria brizantha cv. Marandú. The experiment was carried out in rain fed conditions in 2007 at the Universidad de Papaloapan, Loma Bonita, Oaxaca, Mexico. Six plant distances (broadcast, 25*25 cm, 50*50 cm, 75*75 cm, 100*100 cm and 125*125 cm between rows and plants, respectively) were assessed. To that end, a completely randomized block design with four replicates was set. The following variables were analyzed: pure seed yield (PSY), pure germinable seed yield (GPSY), number of panicles per m-2, panicle length,seed harvested per panicle, 1,000 seed weight, spikelet abscission rate, seed purity and germination. PSY and GPSY showed differences among treatments (PEl objetivo fue evaluar el efecto de la distancia entre plantas en el rendimiento y calidad de semilla de Brachiaria brizantha cv. Marandu. El experimento se realizó en temporal durante 2007, en la Universidad del Papaloapan, Loma Bonita, Oaxaca. Se evaluaron seis distancias entre plantas (voleo, 25 x 25, 50 x 50, 75 x 75, 100 x 100 y 125 x 125 cm entre líneas y plantas, respectivamente), con un diseño de bloques completos al azar, con cuatro repeticiones. Se midió el rendimiento de semilla pura (RSP), rendimiento de semilla pura germinable (RSPG), número de panículas m-2, longitud de panícula, número de semillas cosechadas por panícula, peso de 1,000 semillas, porcentaje de dehiscencia, semilla pura y germinación. El RSP y RSPG varió entre tratamientos (P0.05). Se concluye que el mayor rendimiento de semilla de B. brizantha cv. Marandu, se logró con la distancia 25 x 25 cm entre líneas y plantas, respectivamente. La germinación de la semilla no fue mejorada por ninguno de los tratamientos evaluados

Measurement of the Splitting Function in &ITpp &ITand Pb-Pb Collisions at root&ITsNN&IT=5.02 TeV

Data from heavy ion collisions suggest that the evolution of a parton shower is modified by interactions with the color charges in the dense partonic medium created in these collisions, but it is not known where in the shower evolution the modifications occur. The momentum ratio of the two leading partons, resolved as subjets, provides information about the parton shower evolution. This substructure observable, known as the splitting function, reflects the process of a parton splitting into two other partons and has been measured for jets with transverse momentum between 140 and 500 GeV, in pp and PbPb collisions at a center-of-mass energy of 5.02 TeV per nucleon pair. In central PbPb collisions, the splitting function indicates a more unbalanced momentum ratio, compared to peripheral PbPb and pp collisions.. The measurements are compared to various predictions from event generators and analytical calculations.Peer reviewe

Inclusive Search for a Highly Boosted Higgs Boson Decaying to a Bottom Quark-Antiquark Pair

© 2018 CERN. An inclusive search for the standard model Higgs boson (H) produced with large transverse momentum (pT) and decaying to a bottom quark-antiquark pair (bb) is performed using a data set of pp collisions at s=13 TeV collected with the CMS experiment at the LHC. The data sample corresponds to an integrated luminosity of 35.9 fb-1. A highly Lorentz-boosted Higgs boson decaying to bb is reconstructed as a single, large radius jet, and it is identified using jet substructure and dedicated b tagging techniques. The method is validated with Z→bb decays. The Z→bb process is observed for the first time in the single-jet topology with a local significance of 5.1 standard deviations (5.8 expected). For a Higgs boson mass of 125 GeV, an excess of events above the expected background is observed (expected) with a local significance of 1.5 (0.7) standard deviations. The measured cross section times branching fraction for production via gluon fusion of H→bb with reconstructed pT > 450 GeV and in the pseudorapidity range -2.5 < η < 2.5 is 74±48(stat)-10+17(syst) fb, which is consistent within uncertainties with the standard model prediction

Search for new phenomena in final states with two opposite-charge, same-flavor leptons, jets, and missing transverse momentum in pp collisions at √s=13 TeV

Search results are presented for physics beyond the standard model in final states with two opposite-charge, same-flavor leptons, jets, and missing transverse momentum. The data sample corresponds to an integrated luminosity of 35.9 fb−1 of proton-proton collisions at s√=13 TeV collected with the CMS detector at the LHC in 2016. The analysis uses the invariant mass of the lepton pair, searching for a kinematic edge or a resonant-like excess compatible with the Z boson mass. The search for a kinematic edge targets production of particles sensitive to the strong force, while the resonance search targets both strongly and electroweakly produced new physics. The observed yields are consistent with the expectations from the standard model, and the results are interpreted in the context of simplified models of supersymmetry. In a gauge mediated supersymmetry breaking (GMSB) model of gluino pair production with decay chains including Z bosons, gluino masses up to 1500–1770 GeV are excluded at the 95% confidence level depending on the lightest neutralino mass. In a model of electroweak chargino-neutralino production, chargino masses as high as 610 GeV are excluded when the lightest neutralino is massless. In GMSB models of electroweak neutralino-neutralino production, neutralino masses up to 500-650 GeV are excluded depending on the decay mode assumed. Finally, in a model with bottom squark pair production and decay chains resulting in a kinematic edge in the dilepton invariant mass distribution, bottom squark masses up to 980–1200 GeV are excluded depending on the mass of the next-to-lightest neutralino

Search for electroweak production of charginos and neutralinos in multilepton final states in proton-proton collisions at root s=13 TeV

Results are presented from a search for the direct electroweak production of charginos and neutralinos in signatures with either two or more leptons (electrons or muons) of the same electric charge, or with three or more leptons, which can include up to two hadronically decaying tau leptons. The results are based on a sample of protonproton collision data collected at p s = 13TeV, recorded with the CMS detector at the LHC, corresponding to an integrated luminosity of 35.9 fb1. The observed event yields are consistent with the expectations based on the standard model. The results are interpreted in simpli ed models of supersymmetry describing various scenarios for the production and decay of charginos and neutralinos. Depending on the model parameters chosen, mass values between 180GeV and 1150 GeV are excluded at 95% CL. These results signi cantly extend the parameter space probed for these particles in searches at the LHC. In addition, results are presented in a form suitable for alternative theoretical interpretations.Sponsoring Consortium for Open Access Publishing in Particle Physic

Apomixis y su importancia en la selección y mejoramiento de gramineas forrajeras tropicales. revisión

Apomixis is a reproductive system resulting in seed production without gametes fusion, and produces, through generations, offspring that is a genetic copy from the maternal progenitor. Apomixis importance is widespread among tropical grasses: Bothriochloa, Bouteloua, Brachiaria, Callipedium, Cenchrus, Dichanthium, Eragrostis, Hyparrhenia, Melinis, Panicum, Paspalum, Pennisetum, Setaria, Tripsacum, Urochloa, among the most important. Apomictic species contain diploid as well as polyploid individuals conforming "agamic complexes" and reproductive barriers limited both by apomixis as well as ploidy level which has a great impact on apomictic species utilization. Diploid individuals maintain active the sexuality and these are rare out of the center of specie's genetic origin center. Polyploid individuals in nature are apomictic, and sexual individuals may be induced to polyploidy in the laboratory, allowing hybrid descendants production. Genetic richness originated within the specie's center of diversity is the basis to overcome productive challenges and ecological stability: dry season productivity, nitrogen fixation, forage quality, pest and disease resistance, etc., as it has been shown by successful breeding programs for Brachiaria and Panicum, between the most recognized for Latin America, and Cenchrus in USA. Apomixis research advancements has elucidated the biology for this reproductive process as well as the techniques for its manipulation, however, the impact of this advancements on forage research in México has promoted a critical review on forage genetic resources utilization, resulting in an increased interest on hybrid material production to face the requirements for extensive grazing production systems in Mexico.Apomixis es un tipo reproductivo donde la producción de semilla ocurre sin fusión de gametos, resultando por generaciones, en descendencia que genéticamente, es copia fiel del progenitor materno. La apomixis se encuentra ampliamente distribuida entre las gramí­neas forrajeras tropicales: Bothriochloa, Bouteloua, Brachiaria, Callipedium, Cenchrus, Dichanthium, Eragrostis, Hyparrhenia, Melinis, Panicum, Paspalum, Pennisetum, Setaria, Tripsacum y Urochloa, entre otros. Las especies apomí­cticas contienen individuos diploides y poliploides conformando "complejos agámicos", donde las barreras reproductivas quedan delimitadas por la apomixis y el nivel de ploidí­a, lo que tiene impacto en su aprovechamiento. Individuos diploides mantienen la sexualidad activa y estos son raros fuera del centro de origen de especie. Los individuos poliploides son apomí­cticos y los individuos sexuales poliploides pueden inducirse en el laboratorio, lo que permite obtener descendencia hí­brida. La riqueza genética, originada del centro de diversidad es la base para superar problemas productivos y de estabilidad ecológica: producción durante la sequí­a, fijación de nitrógeno, calidad, resistencia a plagas y enfermedades, como se ha demostrado en casos exitosos en Brachiaria, Panicum y Cenchrus. Los avances en investigación sobre apomixis han elucidado su biologí­a y diversas técnicas para su manejo. Sin embargo, el impacto de estos avances en la investigación sobre forrajes en México, promueve la recapitulación sobre el aprovechamiento de recursos genéticos y el interés en la generación de hí­bridos para las necesidades de producción en pastoreo extensivo en México