Measurement of the ttbar Production Cross Section in ppbar Collisions at sqrt(s)=1.96 TeV using Lepton + Jets Events with Lifetime b-tagging

We present a measurement of the top quark pair ($t\bar{t}$) production cross section ($\sigma_{t\bar{t}}$) in $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV using 230 pb$^{-1}$ of data collected by the D0 experiment at the Fermilab Tevatron Collider. We select events with one charged lepton (electron or muon), missing transverse energy, and jets in the final state. We employ lifetime-based b-jet identification techniques to further enhance the $t\bar{t}$ purity of the selected sample. For a top quark mass of 175 GeV, we measure $\sigma_{t\bar{t}}=8.6^{+1.6}_{-1.5}(stat.+syst.)\pm 0.6(lumi.)$ pb, in agreement with the standard model expectation.Comment: 7 pages, 2 figures, 3 tables Submitted to Phys.Rev.Let

Search for W' bosons decaying to an electron and a neutrino with the D0 detector

This Letter describes the search for a new heavy charged gauge boson W' decaying into an electron and a neutrino. The data were collected with the D0 detector at the Fermilab Tevatron proton-antiproton Collider at a center-of-mass energy of 1.96 TeV, and correspond to an integrated luminosity of about 1 inverse femtobarn. Lacking any significant excess in the data in comparison with known processes, an upper limit is set on the production cross section times branching fraction, and a W' boson with mass below 1.00 TeV can be excluded at the 95% C.L., assuming standard-model-like couplings to fermions. This result significantly improves upon previous limits, and is the most stringent to date.Comment: submitted to Phys. Rev. Let

Manganese Defective Clustering: Influence on the Spectroscopic Features of Ceria-Based Nanomaterials

The influence of manganese modification on the spectroscopic features of manganese-doped CeO2 systems synthesized by the microwave-assisted hydrothermal route and their correlation with the presence of O defective structures were verified, focusing on their interaction with poisonous atmospheres. Raman and electron paramagnetic resonance studies confirmed the presence of defective clusters formed by dipoles and/or quadrupoles. The number of paramagnetic species was found to be inversely proportional to the doping concentration, resulting in an increase in the Mn2+ signal, likely due to the reduction of Mn3+ species after the interaction with CO. X-ray photoelectron spectroscopy data showed the pure system with 33% of its cerium species in the Ce3+ configuration, with an abrupt decrease to 19%, after the first modification with Mn, suggesting that 14% of the Ce3+ species are donating one electron to the Mn2+ ions, thus becoming nonparamagnetic Ce4+ species. On the contrary, 58% of the manganese species remain in the Mn2+ configuration with five unpaired electrons, corroborating the paramagnetic feature of the samples seen in the electron paramagnetic resonance study

Protocol for collection and separation of bone marrow mononuclear cells in Chlorocebus aethiops

Abstract: Chlorocebus aethiops is a species of non-human primate frequently used in biomedical research. Some research involves this species as an experimental model for various diseases and possible treatment with stem cells. The bone marrow is one of the main sources of these cells and provides easy access. The aim of this study was to standardize the protocol of collection and separation of bone marrow in C. aethiops. Ten animals were submitted to puncture of bone marrow with access to the iliac crest and cell separation by density gradient. The bone marrow of C. aethiops had an average of 97% viability. From the results achieved, we can conclude that C. aethiops is an excellent model to obtain and isolate mononuclear cells from bone marrow, fostering several studies in the field of cell therapy

Estaquia de Cuphea calophylla subsp. mesostemon (Koehne) Lourteig (Lythraceae)

As informações a respeito da propagação de Cuphea calophylla subsp. mesostemon (Koehne) Lourteig (Lythraceae) são escassas. As técnicas de propagação podem subsidiar o manejo, fornecendo alternativa para produtores de plantas medicinais e evitando a coleta indiscriminada. O presente trabalho teve como objetivo verificar o efeito de diferentes tipos de estaca, tamanhos e área foliar no enraizamento de estacas semilenhosas. As estacas foram obtidas a partir de plantas espontâneas coletadas na Estação Experimental do Canguiri da Universidade Federal do Paraná (UFPR), localizada em Pinhais - PR. Os experimentos com estaquia foram conduzidos em casa-de-vegetação. O delineamento foi inteiramente casualizado com cinco repetições e 24 estacas por parcela, para todos os experimentos. As estacas obtidas de ramos vegetativos apresentaram maior porcentagem de brotação e massa seca de raízes por estaca em relação àquelas obtidas de ramos reprodutivos, especialmente, as estacas obtidas da parte basal dos ramos vegetativos. As estacas preparadas com 10 e 15 cm de comprimento apresentaram maior número de brotos e maior massa seca de raízes por estaca, em relação às preparadas com 5 cm. As estacas com 3 e 4 pares de folhas apresentaram maior altura, incremento de altura, massa seca de raízes e de brotos por estaca, em relação aos tratamentos com 1 e 2 pares de folhas. Os resultados de propagação vegetativa apontam a estaquia como uma técnica viável para a multiplicação da espécie.Information about the propagation of Cuphea calophylla subsp. mesostemon (Koehne) Lourteig (Lythraceae) is scarce. Propagation techniques may support its management, providing an alternative for medicinal plant producers and avoiding indiscriminate harvests. This study aimed to investigate the effect of different types, sizes and leaf areas of semi-woody cuttings on their rooting. Cuttings were obtained from weeds harvested at the Canguiri Experimental Station of the Paraná Federal University (UFPR), Pinhais Municipality, Paraná State, Brazil. Experiments were carried out in a greenhouse. Experimental design was completely randomized, with five replicates and 24 cuttings per plot. Cuttings obtained from vegetative branches had higher sprouting percentage and root dry matter per cutting relative to those obtained from reproductive branches, especially cuttings obtained from the basal region of vegetative branches. Cuttings prepared with 10 and 15 cm length had larger number of sprouts and higher root dry matter per cutting relative to those prepared with 5 cm. Cuttings presenting 3 and 4 leaf pairs had greater height, increase in height, and root and sprout dry matter per cutting relative to those presenting 1 and 2 leaf pairs. The results regarding vegetative propagation indicate cutting as a viable technique for the multiplication of this species