Corneal thickness measurements in ovines with ultrasonic pachymetry and noncontact specular microscopy

O propósito do presente trabalho foi avaliar os valores da espessura corneana central em córneas de ovinos sadios com o microscópio especular de não-contato e paquímetro ultra-sônico. A espessura corneana central foi determinada em 22 olhos de 11 ovinos, inicialmente com microscópio especular de não-contato (Topcon SP-2000P), seguido pelo paquímetro ultra-sônico (Nidek UP-1000). Os valores médios das medidas corneanas centrais foram 654mm e 665mm com o microscópio especular de não contato e o paquímetro ultra-sônico, respectivamente. As medidas da espessura corneana demonstraram que ambos os instrumentos são confiáveis.The purpose of this study was to evaluate the central corneal thickness values in normal ovine with Topcon SP-2000P noncontact specular microscope and ultrasonic pachymeter. Central corneal thickness was detemined in 22 eyes of 11 ovines, first with a noncontact specular microscopy (Topcon SP-2000P), then using an ultrasonic pachgmeter (Nidek UP-1000). The central corneal measurements were 654mm e 665mm with Topcon and ultrasonic pachymeter, respectively. The instruments were reliable in their measurements

Thickness and density of corneal endothelial cells in ovines

The cornea is transparent layer of the eye, transmission and refraction of light being their main functions. The endothelium, one of the cornea four layers, is a hexagonal unicellular layer that forms a barrier between the stroma and aqueous humor, obstructing the entrance of water and others solutes from the anterior chamber towards the stroma. In the regard to it, a minimum density of these cells is necessary to maintain the performance and clarity of the eye visual capacity. The main objective of the present research was the determination of the density of endothelial cells and their corneal thickness, using a noncontact specular microscope, in 22 eyes from 11 ovines. The average density of the endothelial corneal was 2726 cels/mm² and the thickness 654 µm. The males displayed a higher average density and a smaller cell area than the females.A córnea é transparente, sendo suas principais funções a transmissão e a refração da luz. Compreende quatro camadas, dentre elas, o endotélio corneano, que é constituído por uma única camada de células hexagonais interligadas, formando uma barreira entre o estroma corneano e o humor aquoso, limitando a entrada de água e solutos oriundos da câmara anterior para o estroma. Portanto, uma densidade mínima é necessária para manter a transparência e a funcionalidade corneanas. Objetivou-se determinar a densidade de células endoteliais e a espessura corneanas, utilizando-se microscopia especular de não contato, em 22 olhos provenientes de 11 ovinos. A média de densidade celular endotelial corneana foi de 2726 céls/mm2 e a espessura 654 µm. Os machos apresentaram médias de densidades superiores e áreas celulares inferiores em relação às fêmeas

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

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