349 research outputs found

    Worm control for small ruminants in tropical Asia

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    ACIAR funded a collaborative project between research organisations in Southeast Asia for ILRI and regional partners to explore new ways to control helminth parasites in the tropics. The project aimed to increase small ruminant production in Southeast Asia by controlling internal parasites, which are one of the major constraints to sheep and goat production in the tropics. Control of internal parasites also provides an avenue for general improvement in husbandry methods. The three objectives of the project are: to prevent the spread of resistance to anthelmintics (dewormers) used for control of nematode parasites of sheep and goats in Asia; to assess genetic variation in resistance to gastrointestinal nematode parasites in different breeds of sheep and goats; and to disseminate information about control of internal parasites in the tropics. This publication and the accompanying CD draw together information from a number of sources to describe the state of research and development on worm control in sheep and goats in Asia and the Pacific. Topics of discussion include worm control; economic impacts of worm control; integrated approaches to sustainable parasite control; anthelmintic resistance; appropriate breeds and breeding schemes; options to overcome worm infection; impact of parasitism on the development of small ruminant populations; worm control methods; improving small ruminant productivity; and prevalence of internal parasites

    A Study of Quantum dots of GaSb

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    Abstract. Quantum Dots is a nano structured materials, which is an interesting object for fundamental study as well as for applications. Quantum Dots has been used for optoelectronic devices, such as fast detectors and for lasers. In this paper we report preliminary results of the preparation of quantum dots of GaSb in our laboratory. These dots are prepared by self-organized growth by MOCVD, using Trymethylgalium and Tridismethylaminoantimonat  as metal organic sources and using GaAs as substrate. The results are studied by Scanning Electron Microscope. We propose further characterization of these quantum dots. Studi Mengenai Titik Kuantum GaSbSari. Quantum Dot adalah material yang mempunyai struktur nano, yang merupakan objek untuk penelitian fundamental maupun untuk penerapannya. Dalam makalah ini dilaporakan hasil-hasil yang pertama yang kita peroleh dalam pembuatan Quantum Dot dari GaSb dalam laboratorium kami. Quantum Dot ini telah ditumbuhkan dengan menggunakan penumbuhan yang "selforganized" dengan reactor MOCVD dengan mempergunakan Trimetilgalium dan Trisdismetilantimonat sebagai sumber-sumber metalorganic dan GaAs digunakan sebagai substrat. Hasilnya ditelaah dengan menggunakan SEM. Telat disarankan karakterisasi lanjutan yang harus dilakukan.

    Epitaxy of GaN Film by Hydrogen Plasma Assisted MOCVD

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    Abstract. We have studied the effect of hydrogen plasma on GaN film, grown by plasma-assisted metalorganic chemical vapor deposition (MOCVD). GaN films grown on a sapphire (0001) without the buffer layer have a polycrystalline structure. While films grown using the buffer layer tends to have a single crystal orientation. We have tried to increase the growth rate by varying the TMGa:N ratio. We found that the growth rate of the films were 450 nm/h with TMGa:N ratio of 1:600. However the films show a polycrystalline structure. Using hydrogen plasma during the growth, we have shown by XRD analysis that the films structure was highly oriented in (0002) plane  parallel to substrate and the crystalline quality is improved. Epitaksi Film GaN dengan MOCVD Berbatuan Plasma HidrogenSari. Telah dipelajari efek dari plasma hydrogen pada film Gan, yang ditumbuhkan dengan MOCVD yang dibantu dengan plasma. Film GaN ditumbuhkan di atas safir (0001) tanpa bantuan lapisan penyangga mempunyai struktur polikristalin. Sedangkan film yang ditumbuhkan dengan bantuan lapisan penyangga mempunyai kecenderungan membentuk Kristal dengan orientasi tunggal. Telah dicoba untuk menaikkan kecepatan pertumbuhan Kristal dengan mengubah-ubah perbandingan TMGa:N. Telah diperoleh kecepatan pertumbuhannya menjadi 450nm/jam bila perbandingan tersebut 1:600, akan tetapi strukturnya memperlihatkan sifat polikristal. Dengan bantuan plasma hidrogen analisis XRD menunjukkan bahwa orientasi film sejajar dengan arah (0002) dan sifat kristalnya dapat diperbaiki

    Knowledge, attitude and practice of blood donation among undergraduate students in a public university, Malaysia

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    Blood donation save millions of lives. An increasing demand for blood in almost all medical centers throughout Malaysia indicated the requirement for more blood donors. The current strategy of blood donor programs in all blood centers in order to overcome the shortage of donations of safe blood in Malaysia is to make a maximum effort to recruit safe blood donors from special, low-risk groups, such as university students. The study was to determine the knowledge, attitude, and practices among undergraduate health sciences students regarding blood donations in a public university. A cross-sectional study was conducted among undergraduate health sciences students. The data were collected from February until April 2016 and SPSS, version 20.0 was used to analyze the data. The result revealed, a total of 210 undergraduate health sciences student participated in this study. Approximately, 46.2% had adequate knowledge, 57.1% had a positive attitude towards blood donation and less than 50% of the respondents had ever donated blood. Although there is positive attitude of blood donation among student but there is low level of knowledge of blood donation. Therefore, there is need to intensify public awareness and knowledge on blood donation. The campaign on blood donation should be continued with various methods to create more opportunities for the students, which can greatly enhance their knowledge, promote positive attitude and good blood donation practice

    Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV

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    Results are presented from a search for a W' boson using a dataset corresponding to 5.0 inverse femtobarns of integrated luminosity collected during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV. The W' boson is modeled as a heavy W boson, but different scenarios for the couplings to fermions are considered, involving both left-handed and right-handed chiral projections of the fermions, as well as an arbitrary mixture of the two. The search is performed in the decay channel W' to t b, leading to a final state signature with a single lepton (e, mu), missing transverse energy, and jets, at least one of which is tagged as a b-jet. A W' boson that couples to fermions with the same coupling constant as the W, but to the right-handed rather than left-handed chiral projections, is excluded for masses below 1.85 TeV at the 95% confidence level. For the first time using LHC data, constraints on the W' gauge coupling for a set of left- and right-handed coupling combinations have been placed. These results represent a significant improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe

    Search for the standard model Higgs boson decaying into two photons in pp collisions at sqrt(s)=7 TeV

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    A search for a Higgs boson decaying into two photons is described. The analysis is performed using a dataset recorded by the CMS experiment at the LHC from pp collisions at a centre-of-mass energy of 7 TeV, which corresponds to an integrated luminosity of 4.8 inverse femtobarns. Limits are set on the cross section of the standard model Higgs boson decaying to two photons. The expected exclusion limit at 95% confidence level is between 1.4 and 2.4 times the standard model cross section in the mass range between 110 and 150 GeV. The analysis of the data excludes, at 95% confidence level, the standard model Higgs boson decaying into two photons in the mass range 128 to 132 GeV. The largest excess of events above the expected standard model background is observed for a Higgs boson mass hypothesis of 124 GeV with a local significance of 3.1 sigma. The global significance of observing an excess with a local significance greater than 3.1 sigma anywhere in the search range 110-150 GeV is estimated to be 1.8 sigma. More data are required to ascertain the origin of this excess.Comment: Submitted to Physics Letters

    Measurement of the Lambda(b) cross section and the anti-Lambda(b) to Lambda(b) ratio with Lambda(b) to J/Psi Lambda decays in pp collisions at sqrt(s) = 7 TeV

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    The Lambda(b) differential production cross section and the cross section ratio anti-Lambda(b)/Lambda(b) are measured as functions of transverse momentum pt(Lambda(b)) and rapidity abs(y(Lambda(b))) in pp collisions at sqrt(s) = 7 TeV using data collected by the CMS experiment at the LHC. The measurements are based on Lambda(b) decays reconstructed in the exclusive final state J/Psi Lambda, with the subsequent decays J/Psi to an opposite-sign muon pair and Lambda to proton pion, using a data sample corresponding to an integrated luminosity of 1.9 inverse femtobarns. The product of the cross section times the branching ratio for Lambda(b) to J/Psi Lambda versus pt(Lambda(b)) falls faster than that of b mesons. The measured value of the cross section times the branching ratio for pt(Lambda(b)) > 10 GeV and abs(y(Lambda(b))) < 2.0 is 1.06 +/- 0.06 +/- 0.12 nb, and the integrated cross section ratio for anti-Lambda(b)/Lambda(b) is 1.02 +/- 0.07 +/- 0.09, where the uncertainties are statistical and systematic, respectively.Comment: Submitted to Physics Letters

    Search for new physics in events with opposite-sign leptons, jets, and missing transverse energy in pp collisions at sqrt(s) = 7 TeV

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    A search is presented for physics beyond the standard model (BSM) in final states with a pair of opposite-sign isolated leptons accompanied by jets and missing transverse energy. The search uses LHC data recorded at a center-of-mass energy sqrt(s) = 7 TeV with the CMS detector, corresponding to an integrated luminosity of approximately 5 inverse femtobarns. Two complementary search strategies are employed. The first probes models with a specific dilepton production mechanism that leads to a characteristic kinematic edge in the dilepton mass distribution. The second strategy probes models of dilepton production with heavy, colored objects that decay to final states including invisible particles, leading to very large hadronic activity and missing transverse energy. No evidence for an event yield in excess of the standard model expectations is found. Upper limits on the BSM contributions to the signal regions are deduced from the results, which are used to exclude a region of the parameter space of the constrained minimal supersymmetric extension of the standard model. Additional information related to detector efficiencies and response is provided to allow testing specific models of BSM physics not considered in this paper.Comment: Replaced with published version. Added journal reference and DO

    Measurement of isolated photon production in pp and PbPb collisions at sqrt(sNN) = 2.76 TeV

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    Isolated photon production is measured in proton-proton and lead-lead collisions at nucleon-nucleon centre-of-mass energies of 2.76 TeV in the pseudorapidity range |eta|<1.44 and transverse energies ET between 20 and 80 GeV with the CMS detector at the LHC. The measured ET spectra are found to be in good agreement with next-to-leading-order perturbative QCD predictions. The ratio of PbPb to pp isolated photon ET-differential yields, scaled by the number of incoherent nucleon-nucleon collisions, is consistent with unity for all PbPb reaction centralities.Comment: Submitted to Physics Letters

    Search for leptophobic Z ' bosons decaying into four-lepton final states in proton-proton collisions at root s=8 TeV

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