2,136 research outputs found

    Integrated Nitrogen Management in China

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    Providing China's growing population with higher quality food and a larger share of meat in diets can only be accomplished through increased agricultural productivity, which is usually achieved through higher input of nitrogen to soils. This can lead to nitrate leaching which affects the quality of drinking water, causes emissions of ammonia to the atmosphere, a contributor to the formation of atmospheric particles that are harmful to human health, and to the release of nitrous oxide (N2O), an important global greenhouse gas. This report develops an integrated perspective on agricultural management measures that have multiple benefits on economic development, on the local environment and for global greenhouse gas emissions. The study estimates for the case of China that an integrated nitrogen management approach could increase agricultural production by up to 50 percent while keeping current levels of nitrogen discharge to soil, water and air at the local scale. Compared to the business as usual case, emissions of N2O greenhouse gas emissions would be 25 percent lower. Developed as an activity of IIASA's interdisciplinary Greenhouse Gas Initiative (GGI), the new integrated approach links population increase and demands on food quality with nitrogen fertilizer requiremnts in agriculture, and assesses undesired environmental effects of nitrogen at the local and global scales

    Search for associated Higgs boson production using like charge dilepton events in p(p)over-bar collisions at root s=1.96 TeV

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    We present a search for associated Higgs boson production in the process p (p) over bar -> W/ZH -> l(+/-)l'(+/-) + X in ee, e mu, and mu mu final states. The search is based on data collected by the D0 experiment at the Fermilab Tevatron Collider at root s = 1.96 TeV corresponding to 5.3 fb(-1) of integrated luminosity. We require two isolated leptons (electrons or muons) with the same electric charge and additional kinematic requirements. No significant excess above background is observed, and we set 95% C. L. observed (expected) upper limits on ratio of the production cross section to the standard model prediction of 6.4 (7.3) for a Higgs boson mass of 165 GeV and 13.5 (19.8) for a mass of 115 GeV

    Impacts of Dietary Lysine and Crude Protein on Performance, Hepatic and Renal Functions, Biochemical Parameters, and Histomorphology of Small Intestine, Liver, and Kidney in Broiler Chickens

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    The present study aimed to investigate the effects of increasing dietary lysine (Lys) levels with an adequate dietary crude protein (CP) content, as well as the effects of a reduction in dietary CP content with the recommended amino acid (AAs) level, on the performance, blood biochemical parameters, and histomorphology of the duodenum, liver, and kidney in broiler chickens. A total of 500 broiler chickens were randomly distributed into five dietary treatment groups, following a completely randomized design, where, at the beginning, the control group (C) was fed a diet containing the standard CP and Lys levels: 23% CP with 1.44% Lys during the starter period; 21.5% CP with 1.29% Lys during the growing period; and 19.5% CP with 1.16% Lys during the finishing period. The Lys content was increased by 10% above the recommended control basal requirements in the second group (Gr1) and by 20% in the third group (Gr2), while using the same recommended CP percentage as the C group. The fourth group (Gr3) had a 1% lower CP content and the fifth group had a 2% lower CP content than the C group, with the same recommended AA level as the C group. Increasing the Lys content in the Gr1 group improved the broilers’ weight gains (p \u3c 0.05) during the starter, growing, and finishing periods. Decreasing dietary CP with the standard AA levels (Gr3 and Gr4) did not significantly affect (p \u3e 0.05) the live weight gain, feed intake, or feed conversion ratio (FCR) of the broilers compared with those fed with the C diet. Blood total bilirubin, direct and indirect bilirubin, triglycerides, cholesterol, low-density lipoprotein (LDL), and very LDL were not different among the experimental groups. However, blood aspartate aminotransferase levels were increased (p \u3c 0.05) in the Gr1 and Gr3 groups compared with the other treatment groups. All dietary treatments decreased the serum creatinine levels (p \u3c 0.05) compared with the C group. The Gr2 broilers had greater serum total protein and globulin (p \u3c 0.05) than those receiving the other treatments. Increasing dietary Lys levels resulted in a significant improvement in duodenum villus height and width (p \u3c 0.05), while the low-CP diets resulted in shorter villi length and width, along with degenerated areas and lymphocytic infiltration. Low dietary CP content induced hepatocyte disorganization and moderate degeneration, along with vacuolated hepatic cells, excessive connective tissue, and lymphocytic infiltration. The cortical regions of the kidney exhibited obvious alterations in the Gr3 and Gr4 groups and large interstitial spaces were found between tubules. Renal tubules in the Gr3 and Gr4 groups were smaller in size and some of these tubules were atrophied. In conclusion, reducing dietary CP levels to 1% or 2% lower than the recommended level did not negatively affect growth performance, inducing minimal influence on the blood metabolic indicators of health status, and resulting in moderate alterations to the histomorphology of the duodenum, liver, and kidney. Furthermore, increasing the Lys content by 10% above the recommended level improved the growth performance, health status, and histomorphology of the duodenum, liver, and kidney in broiler chickens

    Study of Zγ events and limits on anomalous ZZγ and Zγγ couplings in pp̄ collisions at s=1.96TeV

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    We present a measurement of the Zγ production cross section and limits on anomalous ZZγ and Zγγ couplings for form-factor scales of Λ=750 and 1000 GeV. The measurement is based on 138 (152) candidates in the eeγ (μμγ) final state using 320(290)pb-1 of pp̄ collisions at s=1.96TeV. The 95% C.L. limits on real and imaginary parts of individual anomalous couplings are |h10,30Z|<0.23, |h20,40Z|<0.020, |h10,30γ|<0.23, and |h20,40γ|<0.019 for Λ=1000GeV. © 2005 The American Physical Society

    A search for charged massive long-lived particles

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    We report on a search for charged massive long-lived particles (CMLLPs), based on 5.2 fb1^{-1} of integrated luminosity collected with the D0 detector at the Fermilab Tevatron ppˉp\bar{p} collider. We search for events in which one or more particles are reconstructed as muons but have speed and ionization energy loss (dE/dx)(dE/dx) inconsistent with muons produced in beam collisions. CMLLPs are predicted in several theories of physics beyond the standard model. We exclude pair-produced long-lived gaugino-like charginos below 267 GeV and higgsino-like charginos below 217 GeV at 95% C.L., as well as long-lived scalar top quarks with mass below 285 GeV.Comment: submitted to Phys. Rev. Letter

    Zgamma production and limits on anomalous ZZgamma and Zgammagamma couplings in ppbar collisions at sqrt(s)=1.96 TeV

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    We present a measurement of ppbar->Zgamma->ll+gamma (l = e, mu) production with a data sample corresponding to an integrated luminosity of 6.2 fb^{-1} collected by the D0 detector at the Fermilab Tevatron ppbar Collider. The results of the electron and muon channels are combined, and we measure the total production cross section and the differential cross section dsigma/dp_T^gamma, where p_T^gamma is the momentum of the photon in the plane transverse to the beamline. The results obtained are consistent with the standard model predictions from next-to-leading order calculations. We use the transverse momentum spectrum of the photon to place limits on anomalous ZZgamma and Zgammagamma couplings

    Search for a Narrow ttbar Resonance in ppbar Collisions at sqrt{s}=1.96 TeV

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    We report a search for a narrow ttbar resonance that decays into a lepton+jets final state based on an integrated luminosity of 5.3/fb of proton-antiproton collisions at sqrt{s}=1.96 TeV collected by the D0 Collaboration at the Fermilab Tevatron Collider. We set upper limits on the production cross section of such a resonance multiplied by its branching fraction to ttbar which we compare to predictions for a leptophobic topcolor Z' boson. We exclude such a resonance at the 95% confidence level for masses below 835 GeV.Comment: 7 pages, 3 figures, submitted to Physical Review Letter

    Search for first generation leptoquark pair production in the electron + missing energy + jets final state

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    We present a search for the pair production of first generation scalar leptoquarks (LQ) in data corresponding to an integrated luminosity of 5.4 fb1^{-1} collected with the D0 detector at the Fermilab Tevatron Collider in ppbar collisions at s=1.96\sqrt{s}=1.96 TeV. In the channel LQLQˉeνeqqLQ \bar{LQ} \rightarrow e\nu_e qq', where q, q' are u or d quarks, no significant excess of data over background is observed, and we set a 95% C.L. lower limit of 326 GeV on the leptoquark mass, assuming equal probabilities of leptoquark decays to eq and νeq\nu_e q'.Comment: 7 pages, 6 figures, submitted to PRD-R

    Search for the standard model and a fermiophobic Higgs boson in diphoton final states

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    We present a search for the standard model Higgs boson and a fermiophobic Higgs boson in the diphoton final states based on 8.2 fb-1 of ppbar collisions collected with the D0 detector at the Fermilab Tevatron Collider. No excess of data above background predictions is observed and upper limits at the 95% C.L. on the cross section multiplied by the branching fraction are set which are the most restrictive to date. A fermiophobic Higgs boson with a mass below 112.9 GeV is excluded at the 95% C.L.Comment: 12 pages, 21 figures, submitted to PR

    Search for WHWH associated production in ppˉp \bar{p} collisions at s=1.96TeV\sqrt{s}=1.96\,{\rm TeV}

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    This report describes a search for associated production of WW and Higgs bosons based on data corresponding to an integrated luminosity of L\cal{L}5.3fb1 \approx 5.3 \rm fb^{-1} collected with the D0 detector at the Fermilab Tevatron ppˉp\bar{p} Collider. Events containing a WνW\rightarrow \ell \nu candidate (with \ell corresponding to ee or μ\mu) are selected in association with two or three reconstructed jets. One or two of the jets are required to be consistent with having evolved from a bb quark. A multivariate discriminant technique is used to improve the separation of signal and backgrounds. Expected and observed upper limits are obtained for the product of the WHWH production cross section and branching ratios and reported in terms of ratios relative to the prediction of the standard model as a function of the mass of the Higgs boson (MHM_{H}). The observed and expected 95% C.L. upper limits obtained for an assumed MH=115GeVM_{H}=115 \rm GeV are, respectively, factors of 4.5 and 4.8 larger than the value predicted by the standard model.Comment: 25 pages, 14 figure
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