Implication of the Mott-limit violation in high-Tc cuprates

The Fermi arc is a striking manifestation of the strong-correlation physics in high-T_c cuprates. In this paper, implications of the metallic transport in the lightly hole-doped regime of the cuprates, where the Fermi arcs are found, are examined in conjunction with competing interpretations of the Fermi arcs in terms of small hole pockets or a large underlying Fermi surface. It is discussed that the latter picture provides a more natural understanding of the metallic transport in view of the Mott-limit argument. Furthermore, it is shown that a suitable modeling of the Fermi arcs in the framework of the Boltzmann theory allows us to intuitively understand why the transport properties are apparently determined by a "small" carrier density even when the underlying Fermi surface, and hence k_F, is large.Comment: 5 pages, 5 figures; manuscript for the Proceedings of SNS2007 to be published as a Special Issue of the Journal of Physics and Chemistry of Solid

Science Frontiers In Galaxy Evolution: Deep-Wide Surveys

Astro2010: The Astronomy and Astrophysics Decadal Survey : Science White Papers no 79. Available online : http://www8.nationalacademies.org/astro2010/DetailFileDisplay.aspx?id=24

Observation of the Baryonic Flavor-Changing Neutral Current Decay Lambda_b -> Lambda mu+ mu-

We report the first observation of the baryonic flavor-changing neutral current decay Lambda_b -> Lambda mu+ mu- with 24 signal events and a statistical significance of 5.8 Gaussian standard deviations. This measurement uses ppbar collisions data sample corresponding to 6.8fb-1 at sqrt{s}=1.96TeV collected by the CDF II detector at the Tevatron collider. The total and differential branching ratios for Lambda_b -> Lambda mu+ mu- are measured. We find B(Lambda_b -> Lambda mu+ mu-) = [1.73+-0.42(stat)+-0.55(syst)] x 10^{-6}. We also report the first measurement of the differential branching ratio of B_s -> phi mu+ mu- using 49 signal events. In addition, we report branching ratios for B+ -> K+ mu+ mu-, B0 -> K0 mu+ mu-, and B -> K*(892) mu+ mu- decays.Comment: 8 pages, 2 figures, 4 tables. Submitted to Phys. Rev. Let

Search for the standard model Higgs boson decaying to a bbˉb\bar{b} pair in events with no charged leptons and large missing transverse energy using the full CDF data set

We report on a search for the standard model Higgs boson produced in association with a vector boson in the full data set of proton-antiproton collisions at $\sqrt{s} = 1.96$ TeV recorded by the CDF II detector at the Tevatron, corresponding to an integrated luminosity of 9.45 fb$^{-1}$. We consider events having no identified charged lepton, a transverse energy imbalance, and two or three jets, of which at least one is consistent with originating from the decay of a $b$ quark. We place 95% credibility level upper limits on the production cross section times standard model branching fraction for several mass hypotheses between 90 and $150 \mathrm{GeV}/c^2$. For a Higgs boson mass of $125 \mathrm{GeV}/c^2$, the observed (expected) limit is 6.7 (3.6) times the standard model prediction.Comment: Accepted by Phys. Rev. Let

Fortalecimiento de los Eslabones de la Cadena de Valor del Frijol en el Norte de Nicaragua

Esta publicación es el resultado de un proceso de sistematización participativo facilitado por el Centro Internacional de Agricultura Tropical (CIAT) para el Programa de Gestión Rural Empresarial, Sanidad y Ambiente (PROGRESA). El presente documento sistematiza la experiencia del fortalecimiento de los eslabones de la cadena de valor del frijol en el norte de Nicaragua, en busca de mejorar la competitividad del sector a través de la articulación de los diferentes actores. Además, este recuento recopila los aprendizajes de la Comisión Técnica de Frijol integrada por representantes de los socios locales del Programa: ASDENIC, Cáritas Estelí, Cáritas Matagalpa y FIDER

Search for the standard model Higgs boson decaying to a bb pair in events with one charged lepton and large missing transverse energy using the full CDF data set

We present a search for the standard model Higgs boson produced in association with a W boson in sqrt(s) = 1.96 TeV p-pbar collision data collected with the CDF II detector at the Tevatron corresponding to an integrated luminosity of 9.45 fb-1. In events consistent with the decay of the Higgs boson to a bottom-quark pair and the W boson to an electron or muon and a neutrino, we set 95% credibility level upper limits on the WH production cross section times the H->bb branching ratio as a function of Higgs boson mass. At a Higgs boson mass of 125 GeV/c2 we observe (expect) a limit of 4.9 (2.8) times the standard model value.Comment: Submitted to Phys. Rev. Lett (v2 contains clarifications suggested by PRL

Search for the standard model Higgs boson decaying to a bb pair in events with two oppositely-charged leptons using the full CDF data set

We present a search for the standard model Higgs boson produced in association with a Z boson in data collected with the CDF II detector at the Tevatron, corresponding to an integrated luminosity of 9.45/fb. In events consistent with the decay of the Higgs boson to a bottom-quark pair and the Z boson to electron or muon pairs, we set 95% credibility level upper limits on the ZH production cross section times the H -> bb branching ratio as a function of Higgs boson mass. At a Higgs boson mass of 125 GeV/c^2 we observe (expect) a limit of 7.1 (3.9) times the standard model value.Comment: To be submitted to Phys. Rev. Let

Health Aspects of the Pre-Departure Phase of Migration

In the second article in a six-part PLoS Medicine series on Migration & Health, Brian Gushulak and Douglas MacPherson discuss the pre-departure phase of migration and the specific health risks and policy needs associated with this phase

Revista Colombiana de Computación. Volumen 7 Número 1 Junio de 2006

Presentamos a la comunidad académica este nuevo volumen de la Revista Colombiana de Computación para el cual se han seleccionado los artículos mejor evaluados en el Congreso EATIS 2006 (Congreso Euroamericano de Telemática y Sistemas de Información), el cuál se llevó a cabo en la ciudad de Santa Marta, Colombia, del 7 al 10 de febrero de 2006 y que contó con el respaldo de las asociaciones IEEE, IEEE Computer Society, ACM y Sociedad Brasilera de Computación.We present to the academic community this new volume of the Colombian Journal of Computing, for which the best evaluated articles have been selected at the EATIS 2006 Congress (Euro-American Congress on Telematics and Information Systems), which took place in the city of Santa Marta, Colombia, from February 7 to 10, 2006, with the support of the IEEE, IEEE Computer Society, ACM and Brazilian Computing Society associations