640 research outputs found

    WHOLESALE DEMAND FOR USDA QUALITY GRADED BOXED BEEF AND EFFECTS OF SEASONALITY

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    This study estimates wholesale demand for pork, chicken, and quality differentiated beef. We estimate meat retailer own- and cross-price demand elasticities for USDA Choice and Select boxed beef. Results indicate that meat retailers have more elastic demand for lower quality graded beef. Retail beef price has a strong positive relationship with Choice and Select boxed beef demand, and a strong negative relationship with wholesale pork and chicken demand. Seasonal analysis reveals demand for both beef quality grades becomes highly price inelastic during the summer months. The two beef quality grades are substitutes during the winter; however, Select beef is not a substitute for Choice beef in the spring and summer.Demand and Price Analysis,

    Oxidation of tertiary amine-derivatized surfaces to control protein adhesion

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    Selective oxidation of omega-tertiary amine self-assembled thiol monolayers to tertiary amine N-oxides is shown to transform the adhesion of model proteins lysozyme and fibrinogen upon them. Efficient preparation of both secondary and tertiary linker amides as judged by X-ray photoelectron spectroscopy (XPS) and water droplet contact angle was achieved with an improved amide bond formation on gold quartz crystal microbalance (QCM) sensors using 2-(1H-7-azabenzotriazol-1-yl)-1,1,3,3-tetramethyl hexafluorophosphate methanaminium uronium (HATU). Oxidation with hydrogen peroxide was similarly assessed, and adhesion of lysozyme and fibrinogen from phosphate buffered saline was then assayed by QCM and imaged by AFM. Tertiary amine-functionalized sensors adsorbed multilayers of aggregated lysozyme, whereas tertiary amine N-oxides and triethylene glycol-terminated monolayers are consistent with small protein aggregates. The surface containing a dimethylamine N-oxide headgroup and ethyl secondary amide linker showed the largest difference in adsorption of both proteins. Oxidation of tertiary amine decorated surfaces therefore holds the potential for selective deposition of proteins and cells through masking and other patterning techniques

    Optical Photometry and Spectroscopy of the Accretion-Powered Millisecond Pulsar HETE J1900.1-2455

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    We present phase resolved optical photometry and spectroscopy of the accreting millisecond pulsar HETE J1900.1-2455. Our R-band light curves exhibit a sinusoidal modulation, at close to the orbital period, which we initially attributed to X-ray heating of the irradiated face of the secondary star. However, further analysis reveals that the source of the modulation is more likely due to superhumps caused by a precessing accretion disc. Doppler tomography of a broad Halpha emission line reveals an emission ring, consistent with that expected from an accretion disc. Using the velocity of the emission ring as an estimate for the projected outer disc velocity, we constrain the maximum projected velocity of the secondary to be 200 km/s, placing a lower limit of 0.05 Msun on the secondary mass. For a 1.4 Msun primary, this implies that the orbital inclination is low, < 20 degrees. Utilizing the observed relationship between the secondary mass and orbital period in short period cataclysmic variables, we estimate the secondary mass to be ~0.085 Msun, which implies an upper limit of ~2.4 Msun for the primary mass.Comment: 8 pages, 6 figures; Accepted for publication in MNRAS. Minor revisions to match final published versio

    L'estime de soi globale et physique Ă  l'adolescence

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    International audienceObjective. From a data collection conducted among junior high-school students, we propose to assess global and physical self-esteem. Indeed, profound physical changes, psychological and social affect this phase of development of the person and the object of this article is to clarify what are the potential impacts of these changes on self-esteem as a function of age and gender. Methods. 579 junior high-school students of the Midi Pyrenees region, aged 11 to 17 years (M = 13.34, SD = 1.20) have informed the Rosenberg self-esteem scale (1965) and the physical self-inventory (Ninot, DeligniĂšres and Fortes, 2000). Results. The reliability of both tools is confirmed from our study sample. The results allow to update significant differences in global and physical self-esteem according to the age and gender of the adolescents. Conclusion. The discussion focuses on the interpretation of gender differences in the assessment of global self-esteem and physical interpretation of the differences in the development of the person.Objectif de l'Ă©tude : À partir d'un recueil de donnĂ©es rĂ©alisĂ© auprĂšs d'Ă©lĂšves de collĂšge, nous proposons d'Ă©valuer l'estime de soi dans les domaines global et physique. En effet, de profondes modifications physiques, psychologiques et sociales affectent cette phase de dĂ©veloppement de la personne et l'objet de cet article est de prĂ©ciser quelles sont les rĂ©percussions possibles de ces transformations sur l'estime de soi en fonction de l'Ăąge et du genre. Sujets : 579 collĂ©gien(ne)s de la rĂ©gion Midi PyrĂ©nĂ©es, ĂągĂ©s de 11 Ă  17 ans (M = 13,34 ; ET = 1,20) ont renseignĂ© l'Ă©chelle unidimensionnelle de Rosenberg (1965) et l'Inventaire de Soi Physique de Ninot, DeligniĂšres et Fortes (2000). RĂ©sultats. La fiabilitĂ© des deux outils utilisĂ©s est confirmĂ©e auprĂšs de notre Ă©chantillon d'Ă©tude. Les rĂ©sultats permettent de mettre Ă  jour des diffĂ©rences significatives d'estime de soi globale et physique en fonction de l'Ăąge et du genre des adolescent(e)s. Conclusion. La discussion s'oriente sur l'interprĂ©tation des diffĂ©rences de genre dans l'Ă©valuation de l'estime de soi globale et physique et sur l'interprĂ©tation de diffĂ©rences au cours du dĂ©veloppement de la personne

    Prospective memory functioning among ecstasy/polydrug users: evidence from the Cambridge Prospective Memory Test (CAMPROMPT)

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    Rationale: Prospective memory (PM) deficits in recreational drug users have been documented in recent years. However, the assessment of PM has largely been restricted to self-reported measures that fail to capture the distinction between event-based and time-based PM. The aim of the present study is to address this limitation. Objectives: Extending our previous research, we augmented the range laboratory measures of PM by employing the CAMPROMPT test battery to investigate the impact of illicit drug use on prospective remembering in a sample of cannabis only, ecstasy/polydrug and non-users of illicit drugs, separating event and time-based PM performance. We also administered measures of executive function and retrospective memory in order to establish whether ecstasy/polydrug deficits in PM were mediated by group differences in these processes. Results: Ecstasy/polydrug users performed significantly worse on both event and time-based prospective memory tasks in comparison to both cannabis only and non-user groups. Furthermore, it was found that across the whole sample, better retrospective memory and executive functioning was associated with superior PM performance. Nevertheless, this association did not mediate the drug-related effects that were observed. Consistent with our previous study, recreational use of cocaine was linked to PM deficits. Conclusions: PM deficits have again been found among ecstasy/polydrug users, which appear to be unrelated to group differences in executive function and retrospective memory. However, the possibility that these are attributable to cocaine use cannot be excluded

    First Observation of barB0 to D*0 pi+pi+pi-pi- Decays

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    We report on the observation of B0bar -> D*0 pi+ pi+ pi- pi- decays. The branching ratio is (0.30 +/- 0.07 +/- 0.06)%. Interest in this particular mode was sparked by Ligeti, Luke and Wise who propose it as a way to check the validity of factorization tests in B0bar -> D*+ pi+ pi- pi- pi0 decays.Comment: 11 pages postscript, also available through http://w4.lns.cornell.edu/public/CLNS, Version to appear in Phys. Rev.

    A Search for Charmless B→VVB\to VV Decays

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    We have studied two-body charmless decays of the BB meson into the final states ρ0ρ0\rho^0 \rho^0, K∗0ρ0K^{*0} \rho^0, K∗0K∗0K^{*0} K^{*0}, K∗0K∗0ˉK^{*0} \bar{K^{*0}}, K∗+ρ0K^{*+} \rho^0, K∗+K∗0ˉK^{*+} \bar{K^{*0}}, and K∗+K∗−K^{*+} K^{*-} using only decay modes with charged daughter particles. Using 9.7 million BBˉB \bar{B} pairs collected with the CLEO detector, we place 90% confidence level upper limits on the branching fractions, (0.46−7.0)×10−5(0.46-7.0)\times 10^{-5}, depending on final state and polarization.Comment: 8 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

    Search for Lepton-Flavor-Violating Decays of B Mesons

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    We have searched a sample of 9.6 million BB-bar events for the lepton-flavor-violating decays B --> h e^{+-} mu^{-+}, B^+ --> h^- e^+ e^+, B^+ --> h^- e^+ mu^+, and B^+ --> h^- mu^+ mu^+, where h is pi, K, rho, and K*(892), a total of sixteen modes. We find no evidence for these decays, and place 90% confidence level upper limits on their branching fractions that range from 1.0 to 8.3 X 10^{-6}.Comment: 8 pages postscript, also available through http://w4.lns.cornell.edu/public/CLNS, PRD R

    Flavor-Specific Inclusive B Decays to Charm

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    We have measured the branching fractions for B -> D_bar X, B -> D X, and B -> D_bar X \ell^+ \nu, where ``B'' is an average over B^0 and B^+, ``D'' is a sum over D^0 and D^+, and``D_bar'' is a sum over D^0_bar and D^-. From these results and some previously measured branching fractions, we obtain Br(b -> c c_bar s) = (21.9 ±\pm 3.7)%, Br(b -> s g) K^- \pi^+) = (3.69 ±\pm 0.20)%. Implications for the ``B semileptonic decay problem'' (measured branching fraction being below theoretical expectations) are discussed. The increase in the value of Br(b -> c c_bar s) due to B−>DXB -> D X eliminates 40% of the discrepancy.Comment: 12 page postscript file, postscript file also available through http://w4.lns.cornell.edu/public/CLN
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