948 research outputs found

    Development and testing of a quantitative food frequency questionnaire for use in Kerala, India

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    Objective: To develop and test a food frequency questionnaire (FFQ) for use in rural areas of Kerala, India. Design: Based on food use and market surveys of the study area, a quantitative 81- item interviewer-administered FFQ was developed. A validation study was conducted consisting of 24-h diet recalls (24HR) administered on 8 days randomly selected over an entire year and two administrations of the FFQ, one at the beginning of the l-year period and the other at the end. FFQ and 24HR-derived nutrient scores were compared using correlation and regression analyses and by examining differences in the nutrient scores. Setting: Rural villages in Ernakulum district, Kerala, South India. Subjecrs: In each of 30 households, the male head of household and female food preparer were enrolled. Results: Pearson (parametric) correlation coefficients (Y,) averaged about 0.50 in comparing nutrient scores derived from the 24HR with those from the first FFQ and about 0.55 in comparing the second FFQ. On average, Spearman correlation coefficients (YJ were slightly lower than the Y, in comparing the scores derived from the first FFQ, but virtually identical for the second FFQ. Regression analyses indicated better agreement in the comparison of the 24HR-derived scores with the first FFQ than the second FFQ. Difference scores, however, tended to be larger in comparing the first FFQ scores with the 24HR. Conclusions: This FFQ produces results broadly comparable to those used in Europe and North America, indicating its suitability for comparing exposures within a study population in reference to health-related endpoints

    Atmospheric Muon Flux at Sea Level, Underground, and Underwater

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    The vertical sea-level muon spectrum at energies above 1 GeV and the underground/underwater muon intensities at depths up to 18 km w.e. are calculated. The results are particularly collated with a great body of the ground-level, underground, and underwater muon data. In the hadron-cascade calculations, the growth with energy of inelastic cross sections and pion, kaon, and nucleon generation in pion-nucleus collisions are taken into account. For evaluating the prompt muon contribution to the muon flux, we apply two phenomenological approaches to the charm production problem: the recombination quark-parton model and the quark-gluon string model. To solve the muon transport equation at large depths of homogeneous medium, a semi-analytical method is used. The simple fitting formulas describing our numerical results are given. Our analysis shows that, at depths up to 6-7 km w. e., essentially all underground data on the muon intensity correlate with each other and with predicted depth-intensity relation for conventional muons to within 10%. However, the high-energy sea-level data as well as the data at large depths are contradictory and cannot be quantitatively decribed by a single nuclear-cascade model.Comment: 47 pages, REVTeX, 15 EPS figures included; recent experimental data and references added, typos correcte

    Relationship building in Vietnamese English written business communication: A systemic functional analysis,

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    English has a long history in Vietnam and in the last two decades, particularly for business communication, it has developed with an unprecedented speed. Despite this ascendancy, there is an absence of research regarding English in Vietnamese business correspondence. The current study is an in-depth investigation of this with a particular focus on the written features of English, reflecting the importance of written documents in this context. This research was framed within the theoretical perspectives of Systemic Functional Linguistics (SFL). 303 business texts from various business sectors composed by Vietnamese writers were collected. They were then analysed with regard to four SFL variables: speech functions, mood, modality and terms of address to establish the nature of the interpersonal written features developing within Vietnam. The findings of the study indicate that the writers employed several linguistic strategies (e.g., using Vietnamese kinship terms and Vietnamese lexis) and non-linguistic strategies (e.g., using emoticons and written giggling) to establish a close relationship with their interactants. Relationship building was also reflected in the employment of politeness strategies to achieve positive politeness effect. These results suggest that SFL is a useful theoretical framework and analytical tool to uncover how English is employed in different socio-cultural contexts to enact social meaning-making processes

    Differential Production Cross Section of Z Bosons as a Function of Transverse Momentum at sqrt{s}=1.8 TeV

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    We present a measurement of the transverse momentum distribution of Z bosons produced in ppbar collisions at sqrt{s}=1.8 TeV using data collected by the D0 experiment at the Fermilab Tevatron Collider during 1994--1996. We find good agreement between our data and a current resummation calculation. We also use our data to extract values of the non-perturbative parameters for a particular version of the resummation formalism, obtaining significantly more precise values than previous determinations.Comment: 10 pages, 2 figures, submitted to Phys. Rev. Letters v2 has margin error correcte

    Search for Squarks and Gluinos in Events Containing Jets and a Large Imbalance in Transverse Energy

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    Using data corresponding to an integrated luminosity of 79 pb-1, D0 has searched for events containing multiple jets and large missing transverse energy in pbar-p collisions at sqrt(s)=1.8 TeV at the Fermilab Tevatron collider. Observing no significant excess beyond what is expected from the standard model, we set limits on the masses of squarks and gluinos and on the model parameters m_0 and m_1/2, in the framework of the minimal low-energy supergravity models of supersymmetry. For tan(beta) = 2 and A_0 = 0, with mu < 0, we exclude all models with m_squark < 250 GeV/c^2. For models with equal squark and gluino masses, we exclude m < 260 GeV/c^2.Comment: 10 pages, 3 figures, Submitted to PRL, Fixed typo on page bottom of p. 6 (QCD multijet background is 35.4 events

    Search for bottom squarks in pbarp collisions at sqrt(s)=1.8 TeV

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    We report on a search for bottom squarks produced in pbarp collisions at sqrt(s) = 1.8 TeV using the D0 detector at Fermilab. Bottom squarks are assumed to be produced in pairs and to decay to the lightest supersymmetric particle (LSP) and a b quark with branching fraction of 100%. The LSP is assumed to be the lightest neutralino and stable. We set limits on the production cross section as a function of bottom squark mass and LSP mass.Comment: 5 pages, Latex. submitted 3-12-1999 to PRD - Rapid Communicatio

    Search for W~1Z~2\widetilde{W}_1\widetilde{Z}_2 Production via Trilepton Final States in ppˉp\bar{p} collisions at s=1.8\sqrt{s}=1.8 TeV

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    We have searched for associated production of the lightest chargino, W~1\widetilde{W}_1, and next-to-lightest neutralino, Z~2\widetilde{Z}_2, of the Minimal Supersymmetric Standard Model in ppˉp\bar{p} collisions at \mbox{s\sqrt{s} = 1.8 TeV} using the \D0 detector at the Fermilab Tevatron collider. Data corresponding to an integrated luminosity of 12.5±0.7\pm 0.7 \ipb were examined for events containing three isolated leptons. No evidence for W~1Z~2\widetilde{W}_1\widetilde{Z}_2 pair production was found. Limits on σ(W~1Z~2)\sigma(\widetilde{W}_1\widetilde{Z}_2)Br(W~1lνZ~1)(\widetilde{W}_1\to l\nu\widetilde{Z}_1)Br(Z~2llˉZ~1)(\widetilde{Z}_2\to l\bar{l}\widetilde{Z}_1) are presented.Comment: 17 pages (13 + 1 page table + 3 pages figures). 3 PostScript figures will follow in a UUEncoded, gzip'd, tar file. Text in LaTex format. Submitted to Physical Review Letters. Replace comments - Had to resumbmit version with EPSF directive

    Direct Measurement of the Top Quark Mass at D0

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    We determine the top quark mass m_t using t-tbar pairs produced in the D0 detector by \sqrt{s} = 1.8 TeV p-pbar collisions in a 125 pb^-1 exposure at the Fermilab Tevatron. We make a two constraint fit to m_t in t-tbar -> b W^+bbar W^- final states with one W boson decaying to q-qbar and the other to e-nu or mu-nu. Likelihood fits to the data yield m_t(l+jets) = 173.3 +- 5.6 (stat) +- 5.5 (syst) GeV/c^2. When this result is combined with an analysis of events in which both W bosons decay into leptons, we obtain m_t = 172.1 +- 5.2 (stat) +- 4.9 (syst) GeV/c^2. An alternate analysis, using three constraint fits to fixed top quark masses, gives m_t(l+jets) = 176.0 +- 7.9 (stat) +- 4.8 (syst) GeV/C^2, consistent with the above result. Studies of kinematic distributions of the top quark candidates are also presented.Comment: 43 pages, 53 figures, 33 tables. RevTeX. Submitted to Phys. Rev.

    Second Generation Leptoquark Search in p\bar{p} Collisions at s\sqrt{s} = 1.8 TeV

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    We report on a search for second generation leptoquarks with the D\O\ detector at the Fermilab Tevatron ppˉp\bar{p} collider at s\sqrt{s} = 1.8 TeV. This search is based on 12.7 pb1^{-1} of data. Second generation leptoquarks are assumed to be produced in pairs and to decay into a muon and quark with branching ratio β\beta or to neutrino and quark with branching ratio (1β)(1-\beta). We obtain cross section times branching ratio limits as a function of leptoquark mass and set a lower limit on the leptoquark mass of 111 GeV/c2^{2} for β=1\beta = 1 and 89 GeV/c2^{2} for β=0.5\beta = 0.5 at the 95%\ confidence level.Comment: 18 pages, FERMILAB-PUB-95/185-

    Search for First Generation Scalar Leptoquark Pairs in ppbar Collisions at sqrt(s)=1.8 TeV

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    We have searched for first generation scalar leptoquark (LQ) pairs in the enu+jets channel using ppbar collider data (integrated luminosity= 115 pb^-1) collected by the DZero experiment at the Fermilab Tevatron during 1992-96. The analysis yields no candidate events. We combine the results with those from the ee+jets and nunu+jets channels to obtain 95% confidence level (CL) upper limits on the LQ pair production cross section as a function of mass and of beta, the branching fraction to a charged lepton. Comparing with the next-to-leading order theory, we set 95% CL lower limits on the LQ mass of 225, 204, and 79 GeV/c^2 for beta=1, 1/2, and 0, respectively.Comment: 14 pages, 4 figures, submitted to Physical Review Letters Replaced to correct visitor addresse
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