388 research outputs found
Efectividad de AQ10 (Ampelomyces quisqualis cepa M-10) en el control biológico del oídio (Podosphaera xanthii).
El oídio de las cucurbitáceas es una enfermedad que disminuye la productividad y provoca pérdidas económicas. El control químico, incrementa costos de roducción y la resistencia de hongos; por ello se buscan alternativas como el control biológico.CONACYT - Consejo Nacional de Ciencias y TecnologíaPROCIENCI
Antagonismo in vitro de diferentes aislados de Trichoderma spp., sobre Macrophomina phaseolina.
Con este trabajo se concluye que la cepa de Trichoderma MS19 tiene un alto potencial antagónico con respecto a las demás cepas al considerar su tasa de crecimiento y porcentaje de inhibición de Macrophomina phaseolina.CONACYT - Consejo Nacional de Ciencias y TecnologíaPROCIENCI
Funcionalidad tecnologica del sistema de producción de una granja lechera en la empresa ganadera Valle del Perú
Se realizó un diagnóstico con el propósito de determinar la funcionalidad tecnológica y la sustentabilidad de la Granja Zenea de la Empresa Ganadera en la región occidental de Cuba. Se aplicó la metodología de Diagnóstico Rural Rápido (DRP). Las fuentes de información secundarias utilizadas fueron: registros de producción de leche, indices reproductivos y económicos a nivel de granja.
La caracterización se efectuó a través de indicadores descriptivos que se relacionan con los componentes del sistema de producción, el productor y sus características, la infraestructura técnico-productiva y aspectos organizacionales. La funcionalidad tecnológica se realizó a partir de variables que se relacionan con los procesos
tecnológicos que se identifican con el sistema de producción. Se realizó una jerarquización de problemas y se definieron los principales indicadores que deben servir para medir la sostenibilidad en la propuesta de transformación del sistema. Se analizaron estadísticamente algunas variables productivas y su comportamiento, para
los efectos de vaquería, año y bimestre, bajo un modelo lineal de efectos fijos con interacción. El sistema estudiado se caracteriza por ser un sistema de producción típico de la región, con mediano nivel tecnológico y problemas que en su conjunto repercuten en los bajos
niveles de producción, ingresos y rentabilidad. Se identificaron a partir de la caracterización realizada los problemas, lo que permitió laborar una estrategia general y específica, así como las principales acciones de carácter técnico-organizativo que se deben tomar para lograr a través del tiempo la sostenibilidad y el mejoramiento de
la productividad del sistema estudiado
Antagonismo in vitro de diferentes aislados de Trichoderma spp., sobre Macrophomina phaseolina.
Con este trabajo se concluye que la cepa de Trichoderma MS19 tiene un alto potencial antagónico con respecto a las demás cepas al considerar su tasa de crecimiento y porcentaje de inhibición de Macrophomina phaseolina.CONACYT - Consejo Nacional de Ciencias y TecnologíaPROCIENCI
Realistic Model of the Nucleon Spectral Function in Few- and Many- Nucleon Systems
By analysing the high momentum features of the nucleon momentum distribution
in light and complex nuclei, it is argued that the basic two-nucleon
configurations generating the structure of the nucleon Spectral Function at
high values of the nucleon momentum and removal energy, can be properly
described by a factorised ansatz for the nuclear wave function, which leads to
a nucleon Spectral Function in the form of a convolution integral involving the
momentum distributions describing the relative and center-of-mass motion of a
correlated nucleon-nucleon pair embedded in the medium. The Spectral Functions
of and infinite nuclear matter resulting from the convolution formula
and from many-body calculations are compared, and a very good agreement in a
wide range of values of nucleon momentum and removal energy is found.
Applications of the model to the analysis of inclusive and exclusive processes
are presented, illustrating those features of the cross section which are
sensitive to that part of the Spectral Function which is governed by
short-range and tensor nucleon-nucleon correlations.Comment: 40 pages Latex , 16 ps figures available from the above e-mail
address or from [email protected]
Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV
Results are presented from a search for a W' boson using a dataset
corresponding to 5.0 inverse femtobarns of integrated luminosity collected
during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV.
The W' boson is modeled as a heavy W boson, but different scenarios for the
couplings to fermions are considered, involving both left-handed and
right-handed chiral projections of the fermions, as well as an arbitrary
mixture of the two. The search is performed in the decay channel W' to t b,
leading to a final state signature with a single lepton (e, mu), missing
transverse energy, and jets, at least one of which is tagged as a b-jet. A W'
boson that couples to fermions with the same coupling constant as the W, but to
the right-handed rather than left-handed chiral projections, is excluded for
masses below 1.85 TeV at the 95% confidence level. For the first time using LHC
data, constraints on the W' gauge coupling for a set of left- and right-handed
coupling combinations have been placed. These results represent a significant
improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe
Search for the standard model Higgs boson decaying into two photons in pp collisions at sqrt(s)=7 TeV
A search for a Higgs boson decaying into two photons is described. The
analysis is performed using a dataset recorded by the CMS experiment at the LHC
from pp collisions at a centre-of-mass energy of 7 TeV, which corresponds to an
integrated luminosity of 4.8 inverse femtobarns. Limits are set on the cross
section of the standard model Higgs boson decaying to two photons. The expected
exclusion limit at 95% confidence level is between 1.4 and 2.4 times the
standard model cross section in the mass range between 110 and 150 GeV. The
analysis of the data excludes, at 95% confidence level, the standard model
Higgs boson decaying into two photons in the mass range 128 to 132 GeV. The
largest excess of events above the expected standard model background is
observed for a Higgs boson mass hypothesis of 124 GeV with a local significance
of 3.1 sigma. The global significance of observing an excess with a local
significance greater than 3.1 sigma anywhere in the search range 110-150 GeV is
estimated to be 1.8 sigma. More data are required to ascertain the origin of
this excess.Comment: Submitted to Physics Letters
Measurement of the Lambda(b) cross section and the anti-Lambda(b) to Lambda(b) ratio with Lambda(b) to J/Psi Lambda decays in pp collisions at sqrt(s) = 7 TeV
The Lambda(b) differential production cross section and the cross section
ratio anti-Lambda(b)/Lambda(b) are measured as functions of transverse momentum
pt(Lambda(b)) and rapidity abs(y(Lambda(b))) in pp collisions at sqrt(s) = 7
TeV using data collected by the CMS experiment at the LHC. The measurements are
based on Lambda(b) decays reconstructed in the exclusive final state J/Psi
Lambda, with the subsequent decays J/Psi to an opposite-sign muon pair and
Lambda to proton pion, using a data sample corresponding to an integrated
luminosity of 1.9 inverse femtobarns. The product of the cross section times
the branching ratio for Lambda(b) to J/Psi Lambda versus pt(Lambda(b)) falls
faster than that of b mesons. The measured value of the cross section times the
branching ratio for pt(Lambda(b)) > 10 GeV and abs(y(Lambda(b))) < 2.0 is 1.06
+/- 0.06 +/- 0.12 nb, and the integrated cross section ratio for
anti-Lambda(b)/Lambda(b) is 1.02 +/- 0.07 +/- 0.09, where the uncertainties are
statistical and systematic, respectively.Comment: Submitted to Physics Letters
Search for new physics in events with opposite-sign leptons, jets, and missing transverse energy in pp collisions at sqrt(s) = 7 TeV
A search is presented for physics beyond the standard model (BSM) in final
states with a pair of opposite-sign isolated leptons accompanied by jets and
missing transverse energy. The search uses LHC data recorded at a
center-of-mass energy sqrt(s) = 7 TeV with the CMS detector, corresponding to
an integrated luminosity of approximately 5 inverse femtobarns. Two
complementary search strategies are employed. The first probes models with a
specific dilepton production mechanism that leads to a characteristic kinematic
edge in the dilepton mass distribution. The second strategy probes models of
dilepton production with heavy, colored objects that decay to final states
including invisible particles, leading to very large hadronic activity and
missing transverse energy. No evidence for an event yield in excess of the
standard model expectations is found. Upper limits on the BSM contributions to
the signal regions are deduced from the results, which are used to exclude a
region of the parameter space of the constrained minimal supersymmetric
extension of the standard model. Additional information related to detector
efficiencies and response is provided to allow testing specific models of BSM
physics not considered in this paper.Comment: Replaced with published version. Added journal reference and DO
- …