Ecofisiología de los plátanos en zona de altitud de Colombia en relación con su susceptibilidad a las cercosporiasis: informe final.

El cultivo del plátano en Colombia se constituye en un renglón de importancia desde el punto de vista alimentario y social. Una de las enfermedades de importancia en este cultivo es la sigatoka negra; en este estudio se analiza la susceptibilidad del cultivo de plátano a esta enfermedad, se analizó igualmente su conocimiento epidemiológico y el manejo de esta enfermedad para la zona cafetera de Colombia.Plátano-Musa sapientu

Efecto del tamaño de la semilla sobre los parámetros de crecimiento y producción en plátano clon Dominico-Hartón (Musa AAB, Simmonds).

Se concluye que el tamaño (peso) de la semilla afecta la duración de la fase de siembra a floración, en forma inversa y directa, de floración a cosecha. A menor peso del rizoma corresponde un mayor tiempo, reflejado en la emisión de un mayor número de hojas. El tamaño de la semilla no influye sobre la altura de la planta, el perímetro de seudotallo, el número de hojas al momento de la floración, el número de dedos y, lo que es más importante, en el peso del racimo. El peso y la calidad del racimo son parámetros de producción que no están influidos por el peso de la semilla. Ellos, aparentemente, están gobernados por factores intrínsecos de la planta. En el caso del segundo ciclo de producción, el tamaño de la semilla influye únicamente en la duración del ciclo vegetativo, pero sin ejercer ningún efecto sobre el peso del racimoPlátano-Musa sapientu

Actividad fisiológica de híbridos y clones de plátano y banano en relación con su reacción a la sigatoka negra.

Se utilizaron los híbridos de plátano y banano desarrollados por la Fundación Hondureña de Investigación Agrícola (FHIA), y los cultivares de referencia IMTP (International Musa Testing Program), sembrados en la localidad de Zabaletas, municipio de Restrepo (Colombia), a 1420 m.s.n.m., 994 mm de precipitación anual, temperatura promedio 19.3°C y 89.6 de humedad relativa. Se estudió la relación funcional entre las tasas de intercambio gaseoso y la incidencia de la sigatoka negra (Mycosphaerella fijiensis) en los híbridos FHIA y cultivares de referencia IMTP. Se observó una actividad fotosintética diferencial entre los materiales evaluados. Las mayores tasas de fotosíntesis neta se presentaron en FHIA 1, FHIA 2, Pisang Lilin, Burmanicoides y MB Tani, y las menores en FHIA 3, FHIA 6, Malaccensis, Niyarma Yik y NBA 14. Las plantas con tasa más alta de fotosíntesis y mayor conductancia estomática, presentaron un mayor nivel de resistencia a la enfermedad. Los cultivares Niyarma Yik y Dominico-Hartón, clasificados como susceptibles, presentaron las menores tasas de fotosíntesis, pero esta tendencia no se cumplió en el material Malaccensis que, con la menor tasa (11.18 moles CO2 m-2 s-1), fue clasificado como altamente resistente. La penetración mecánica del poro estomático por parte del hongo causante de la sigatoka negra, compromete seriamente el proceso de intercambio de gases, lo cual puede reflejarse en una alteración de la fotosíntesis y la conductancia, al perder las hojas su capacidad de regular la apertura y cierre de los estomas, como efectivamente lo sugieren los resultados de este experiment

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

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

Measurement of isolated photon production in pp and PbPb collisions at sqrt(sNN) = 2.76 TeV

Isolated photon production is measured in proton-proton and lead-lead collisions at nucleon-nucleon centre-of-mass energies of 2.76 TeV in the pseudorapidity range |eta|<1.44 and transverse energies ET between 20 and 80 GeV with the CMS detector at the LHC. The measured ET spectra are found to be in good agreement with next-to-leading-order perturbative QCD predictions. The ratio of PbPb to pp isolated photon ET-differential yields, scaled by the number of incoherent nucleon-nucleon collisions, is consistent with unity for all PbPb reaction centralities.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

Search for leptophobic Z ' bosons decaying into four-lepton final states in proton-proton collisions at root s=8 TeV

Peer reviewe

Search for black holes and other new phenomena in high-multiplicity final states in proton-proton collisions at root s=13 TeV

Peer reviewe