717 research outputs found

    CP violation in B decays: Experimental aspects

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    This lecture, given at the 2005 European School of High-Energy Physics in Austria in succession of the series on CP Violation by Robert Fleischer, sheds light on the topic from a slightly different perspective, which is meant to be a link between theory and the daily work of experimentalists. An overview of Bmeson experimental history and phenomenology is followed by a description of B-meson production techniques, facilities worldwide, and a list of important present and future experiments. Current analyses are discussed, and their latest results (as of summer of 2005) are given

    Development of a System for Directed Evolution of \u3cem\u3eArabidopsis\u3c/em\u3e Formate Dehydrogenase to Utilize NADP as a Cofactor

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    Formate dehydrogenase (FDH) is a NAD-dependent enzyme found in methylotrophic bacteria, yeast and plants. This enzyme catalyzes the reversible oxidation of formate to carbon dioxide. The goal of this research was to determine the feasibility of using a directed evolution approach to generate an altered Arabidopsis FDH with a high affinity for NADP as a cofactor. A PCR procedure that induced approximately 1.5 mutations in the wild-type Arabidopsis FDH sequence per thousand base pairs was developed and the amplified products were transformed into E. coli cells. Approximately 1300 cell lines were assayed in 96-well microplates for activity with NADP+ and 100 putative mutants were selected for further study. One particular mutant line, pFDH-18, possessed reproducible NADP+-FDH activity. Sequence analysis showed that a single T in the wild-type DNA sequence had been changed to a G. The result of this mutation was that an isoleucine (Ile) residue at position 188 in the wild-type enzyme was converted to a methionine. This particular Ile residue is conserved in the known FDH sequences from higher plants and is located in the region of the enzyme that contains the binding domain for the NAD cofactor

    Predictions with Lattice QCD

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    In recent years, we used lattice QCD to calculate some quantities that were unknown or poorly known. They are the q2q^2 dependence of the form factor in semileptonic DKlνD\to Kl\nu decay, the leptonic decay constants of the D+D^+ and DsD_s mesons, and the mass of the BcB_c meson. In this paper, we summarize these calculations, with emphasis on their (subsequent) confirmation by measurements in e+ee^+e^-, γp\gamma p and pˉp\bar{p}p collisions.Comment: 5 pages; update of hep-lat/0509169, with experimental confirmation of form factors from Belle and fDs from BaBar; presented at SciDAC 2006 for the Fermilab Lattice, MILC, and HPQCD Collaboration

    Cool Companions to White Dwarf Stars from the Two Micron All Sky Survey All Sky Data Release

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    We present the culmination of our near-infrared survey of the optically spectroscopically identified white dwarf stars from the McCook and Sion catalog, conducted using photometric data from the Two Micron All Sky Survey final All Sky Data Release. The color selection technique, which identifies candidate binaries containing a white dwarf and a low-mass stellar (or substellar) companion via their distinctive locus in the near-infrared color-color diagram, is demonstrated to be simple to apply and to yield candidates with a high rate of subsequent confirmation. We recover 105 confirmed binaries, and identify 27 firm candidates (19 of which are new to this work) and 21 tentative candidates (17 of which are new to this work) from the 2MASS data. Only a small number of candidates from our survey have likely companion spectral types later than M5, none of which is an obvious L-type (i.e., potential brown dwarf) companion. Only one previously known white dwarf + brown dwarf binary is detected. This result is discussed in the context of the 2MASS detection limits, as well as other recent observational surveys that suggest a very low rate of formation (or survival) for binary stars with extreme mass ratios

    Drought-Ready Communities: A Guide to Community Drought Preparedness

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    Table of Contents Introduction to Drought-Ready Communities........................................................ 4 Section 1. Getting Started: Invite the Community to Participate, Commit to the Process...................... 7 1.1 Establish a leadership team that includes individuals with responsibility for monitoring, communication, and implementation .............................................. 7 1.2 Identify stakeholders or groups in the community that may need additional resources to participate in the Drought-Ready Communities process .................... 8 1.3 Include government agencies and regulators ....................................... 9 1.4 Develop a contact list ................................................................ 9 1.5 Gather community perceptions of drought .................................................. 10 Section 2. Information Gathering: Understand Water Sources and Uses, Develop a Drought History . 11 2.1 Identify water sources and uses ....................................................... 11 2.2 Learn how drought has affected the community in the past ........................ 12 2.3 Gather data on water and climate ................................................................. 13 2.4 List factors that affect the severity of drought impacts ..................................... 1

    Mediterranean diet, diet quality, and bone mineral content in adolescents: the HELENA study

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    Summary: Dietary scores, rather than individual nutrients, allow exploring associations between overall diet and bone health. The aim of the present study was to assess the associations between the Mediterranean Diet Score for Adolescents (MDS-A) and the Diet Quality Index for Adolescents (DQI-A) and bone mineral content (BMC) among Spanish adolescents. Our results do not support an association between dietary scores or indices and BMC in adolescents. Introduction: To assess the associations between the MDS-A and a DQI-A with the BMC measured with dual-energy X-ray absorptiometry. Methods: The MDS-A and the DQI-A were calculated in 179 Spanish adolescents, based on two 24-h dietary recalls from the HELENA cross-sectional study. The associations between the diet scores and the BMC outcomes [total body less head (TBLH), femoral neck (FN), lumbar spine (LS), and hip] were analyzed using logistic regression models adjusting for several confounders. Results: Four hundred ninety-two models were included and only fruits and nuts and cereal and roots were found to provide significant ORs with regard to BMC. The risk of having low BMC reduced by 32% (OR 0.684; CI 0.473–0.988) for FN when following the ideal MDS-A, but this association lost significance when adjusting for lean mass and physical activity. For every 1-point increase in the cereal and root and the fruit and nut components, the risk of having low FN diminished by 56% (OR 0.442; CI 0.216–0.901) and by 67% (OR 0.332; CI 0.146–0.755), respectively. Conclusion: An overall dietary score or index is not associated with BMC in our adolescent Spanish sample
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