Search for the Standard Model Higgs Boson in the ZH --> neutrino-neutrino-b-b channel

We report a search for the standard model (SM) Higgs boson based on data collected by the D0 experiment at the Fermilab Tevatron Collider, corresponding to an integrated luminosity of 260 pb^-1. We study events with missing transverse energy and two acoplanar b-jets, which provide sensitivity to the ZH production cross section in the neutrino-neutrino-b-b channel and to WH production, when the lepton from the W -> lepton+neutrino decay is undetected. The data are consistent with the SM background expectation, and we set 95% C.L. upper limits on sigma(p p-bar -> ZH/WH) x B(H -> b b-bar) from 3.4/8.3 to 2.5/6.3 pb, for Higgs masses between 105 and 135 GeV.Comment: submitted to Phys. Rev. Letter

Efeitos de substratos e das dimensões dos recipientes na qualidade das mudas de Tabebuia impetiginosa (Mart. Ex D.C.) Standl. Effects of substrata and containers dimensions on the quality of Tabebuia impetiginosa (Mart. Ex D.C.) Standl. seedlings

A crescente demanda por mudas de espécies florestais nativas tem exigido pesquisas relacionadas com o uso de substratos e recipientes, capazes de proporcionar mudas que apresentem elevadas taxas de crescimento inicial e de sobrevivência após o plantio. Este trabalho objetivou avaliar a produção de mudas de Tabebuia impetiginosa (Mart. ex D.C.) Standl (ipê-roxo), em condições acessíveis aos pequenos e médios produtores rurais. O ensaio foi instalado em área experimental localizada no Departamento de Fitotecnia (CCA/UFPB), em Areia, PB. O delineamento utilizado foi em blocos ao acaso, com 14 blocos. Os tratamentos consistiram da combinação dos substratos: S1 - terra de subsolo e S2 - terra de subsolo + composto orgânico e de sacos de polietileno preto nas seguintes dimensões: I - 20 x 36,5 cm; II -15 x 32 cm; III - 13 x 25,5 cm; e IV - 13,5 x 19 cm. Para todas as variáveis estudadas, o recipiente I e o substrato S2 sobressaíram em relação aos demais. Entretanto, considerando a diferença entre os resultados e a demanda de substrato e mão-de-obra exigida, no primeiro caso recomenda-se o recipiente II com o substrato S2, para a produção de mudas dessa espécie.<br>The growing demand for seedlings of native species has required research on the use of substrata and containers capable of producing seedlings with high initial growth and surviving rates after planting. This work aimed to evaluate the effects of substrata easily found in farms, and the size of containers used to produce seedlings of Tabebuia impetiginosa (Mart. ex D.C.) Standl. (Ipê roxo). The experiment was conducted in an experimental field of the Department of Agronomy-CCA/UFPB, District of Areia. The experiment was carried out in a randomized block design, totalizing 14 blocks. The treatments consisted of combinations of the following substratas: S1-subsoil and S2-subsoil plus organic compost and polyethylene bags with the following dimensions: I - 20 x 36.5 cm; II - 15 x 32 cm; III - 13 x 25.5 cm; IV - 13.5 x 9 cm. For all the studied variables, the container I and substratum S2 gave the best results. However, considering the difference among the results and the demand for substratum and handling in the first case, it is recommended the use of container II and substratum S2 in the production of seedlings of this species