127 research outputs found

    D* Production in Deep Inelastic Scattering at HERA

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    This paper presents measurements of D^{*\pm} production in deep inelastic scattering from collisions between 27.5 GeV positrons and 820 GeV protons. The data have been taken with the ZEUS detector at HERA. The decay channel D∗+→(D0→K−π+)π+D^{*+}\to (D^0 \to K^- \pi^+) \pi^+ (+ c.c.) has been used in the study. The e+pe^+p cross section for inclusive D^{*\pm} production with 5<Q2<100GeV25<Q^2<100 GeV^2 and y<0.7y<0.7 is 5.3 \pms 1.0 \pms 0.8 nb in the kinematic region {1.3<pT(D∗±)<9.01.3<p_T(D^{*\pm})<9.0 GeV and ∣η(D∗±)∣<1.5| \eta(D^{*\pm}) |<1.5}. Differential cross sections as functions of p_T(D^{*\pm}), η(D∗±),W\eta(D^{*\pm}), W and Q2Q^2 are compared with next-to-leading order QCD calculations based on the photon-gluon fusion production mechanism. After an extrapolation of the cross section to the full kinematic region in p_T(D^{*\pm}) and η\eta(D^{*\pm}), the charm contribution F2ccˉ(x,Q2)F_2^{c\bar{c}}(x,Q^2) to the proton structure function is determined for Bjorken xx between 2 ⋅\cdot 10−4^{-4} and 5 ⋅\cdot 10−3^{-3}.Comment: 17 pages including 4 figure

    Observation of Scaling Violations in Scaled Momentum Distributions at HERA

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    Charged particle production has been measured in deep inelastic scattering (DIS) events over a large range of xx and Q2Q^2 using the ZEUS detector. The evolution of the scaled momentum, xpx_p, with Q2,Q^2, in the range 10 to 1280 GeV2GeV^2, has been investigated in the current fragmentation region of the Breit frame. The results show clear evidence, in a single experiment, for scaling violations in scaled momenta as a function of Q2Q^2.Comment: 21 pages including 4 figures, to be published in Physics Letters B. Two references adde

    Measurement of the dijet invariant mass cross section in proton anti-proton collisions at sqrt{s} = 1.96 TeV

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    The inclusive dijet production double differential cross section as a function of the dijet invariant mass and of the largest absolute rapidity of the two jets with the largest transverse momentum in an event is measured in proton anti-proton collisions at sqrt{s} = 1.96 TeV using 0.7 fb^{-1} integrated luminosity collected with the D0 detector at the Fermilab Tevatron Collider. The measurement is performed in six rapidity regions up to a maximum rapidity of 2.4. Next-to-leading order perturbative QCD predictions are found to be in agreement with the data.Comment: Published in Phys. Lett. B, 693, (2010), 531-538, 8 pages, 2 figures, 6 table

    Measurement of the WZ→ℓΜℓℓWZ\rightarrow \ell\nu\ell\ell cross section and limits on anomalous triple gauge couplings in ppˉp\bar{p} collisions at s\sqrt{s} = 1.96 TeV

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    We present a new measurement of the WZ→ℓΜℓℓWZ\rightarrow \ell\nu\ell\ell (ℓ=e,ÎŒ\ell = e,\mu) cross section and limits on anomalous triple gauge couplings. Using 4.1 fb−1^{-1} of integrated luminosity of ppˉp\bar{p} collisions at s=1.96\sqrt{s} = 1.96 TeV, we observe 34 WZWZ candidate events with an estimated background of 6.0±0.46.0 \pm 0.4 events. We measure the WZWZ production cross section to be 3.90−0.90+1.063.90^{+1.06}_{-0.90} pb, in good agreement with the standard model prediction. We find no evidence for anomalous WWZWWZ couplings and set 95% C.L. limits on the coupling parameters, −0.075<λZ<0.093-0.075 < \lambda_{Z} < 0.093 and −0.027<ΔÎșZ<0.080-0.027 < \Delta\kappa_{Z} < 0.080, in the HISZ parameterization for a Λ=2\Lambda = 2 TeV form factor scale. These are the best limits to date obtained from the direct measurement of the WWZWWZ vertex.Comment: 8 pages, 7 figures, 2 table

    History of ESL Pronunciation Teaching

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    This chapter tells the story of over 150 years in the teaching of English as a second language (ESL) pronunciation. An analysis of historical resources may reveal a reliable history of pronunciation teaching. A consistent theme within the historical record is that prior to the second half of the nineteenth century pronunciation received little attention in L2 classrooms. Beginning in the 1850s and continuing for the next 30 years, early innovators such as Berlitz, Gouin, Marcel, and Predergast were rejecting and transitioning away from classical approaches. A change that resulted in pronunciation teaching\u27s considerably more consequential second wave was the formation in Paris during the period 1886-1889 of the International Phonetic Association. The 1950s-1970s coincide with a slow rise of attention to innovations in how to teach pronunciation. If we may speculate on the future of ESL pronunciation teaching, there is every reason to feel optimistic

    Virulence Factors IN Fungi OF Systemic Mycoses

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    Proceedings of the 2016 Childhood Arthritis and Rheumatology Research Alliance (CARRA) Scientific Meeting

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    Effects, Transfer, and Fate of RDX from Aged Soil in Plants and Worms

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    The objectives of this study were to provide data that can be used to predict exposure-based effects of RDX in aged soil on multiple endpoint organisms representing two trophic levels. These data can be used for defining criteria or reference values for environmental management and conducting specific risk assessment. Dose–response experiments formed the basis for the evaluation of toxic effects and transfer of contaminants from soil into two trophic levels. Long-term exposure tests were conducted to evaluate chronic, sublethal, toxicity and transfer of aged soil-based explosives, with RDX as main contaminant. In these tests, plants were exposed for 55 days in the greenhouse, biomass was determined and residues of explosives parent compounds and RDX metabolites were analyzed using HPLC techniques. Worms were exposed for 28 days (Eisenia fetida) and 42 days (Enchytraeus crypticus) in the laboratory, biomass and number were determined, and tissues were analyzed for explosives compounds. The plants tolerated concentrations up to 1540 mg RDX kg-1 soil-DW. Biomass of Lolium perenne was not significantly related to soil-RDX concentration, while biomass of Medicago sativa significantly increased. No screening benchmark for RDX in soil for plants was calculated, since concentrations up to 1540 mg kg-1 soil failed to reduce biomass by 20% as required for a LOEC. RDX, RDX-metabolite MNX, and accompanying HMX concentrations in plants were significantly related to concentrations in soil after 55 days of exposure (RDX: R2 = 0.77–0.89; MNX R2 = 0.53–0.77; HMX: R2 = 0.67–0.71). The average bioconcentration factors (BCF) were for RDX 17 in L. perenne and 37 in M. sativa, and for HMX 2 in L. perenne and 44 in M. sativa. The worms also tolerated concentrations up to 1540 mg RDX kg-1 soil-DW. Biomass of E. fetida adults decreased with soil-RDX concentration, and a LOEC of 1253 mg kg-1 soil-DW was estimated. RDX concentrations in E. fetida were significantly related to concentrations in soil after 28-day exposure (R2 = 0.88). The average BCF in E. fetida for RDX was 1. Because in response to exposure to RDX-contaminated soil the RDX concentrations in plants increased initially and decreased subsequently, while those in worms increased continuously, RDX in worm tissues may accumulate to higher concentrations than in plant tissues, regardless of the low average BCF for worms

    Macro-encapsulation of heat storage phase-change materials for use in residential buildings. First quarterly progress report, September 29--December 29, 1976

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    Objectives are to assess the feasibility of macro-encapsulated PCM's for residential solar systems, to develop and evaluate such materials. Five PCM's have been selected from encapsulation studies. Encapsulated storage media were evaluated theoretically in storage beds with air and water as the heat transfer medium. Cylindrical, tetrahedral, and pillow shapes are being evaluated for the encapsulated PCM. Encapsulant materials under consideration are multilayer flexible plastic films, steel cans, and plastic bottles

    Macro-encapsulation of heat storage phase-change materials for use in residential buildings. Third quarterly progress report, March 29, 1977--June 29, 1977

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    Objectives are to assess the feasibility of macro-encapsulated PCMs for residential solar systems and to develop and evaluate such materials. Encapsulant materials under consideration are multilayer flexible plastic films, steel cans, and plastic bottles. PCMs under study are Mg(NO/sub 3/)/sub 2/.6H/sub 2/O, naphthalene-benzoic acid eutectic, Mg(NO/sub 3/)/sub 2/.6H/sub 2/O-NH/sub 4/NO/sub 3/ eutectic, and CaCl/sub 2/.6H/sub 2/O. Compatibility studies between the PCMs and encapsulant materials are continuing. A test device has been constructed, and is ready for use
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