219 research outputs found

    Broad bed maker technology package innovations in Ethiopian farming systems: An ex post impact assessment

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    This report is the latest of two separate ex post impact assessments conducted by ILRI 10 years apart. It provides timely insights into the welfare impacts of a technology package introduced in the early 1990s into the crop-livestock farming system of the Ethiopian highlands rich Vertisol soils. The Broad Bed Maker (BBM) was developed in the late 1980s from the traditional dual oxen drawn plough, the maresha by the Joint Vertisol Project (JVP). ILRI (formerly known as ILCA) in Ethiopia was one of five collaborating institutions on this project. The aim of the JVP was to improve the productivity of 7.6 million hectares of Vertisol soils in the Ethiopian highlands - 60% of Ethiopia's total Vertisols. The BBM is a type of a plough that was developed from the traditional dual oxen drawn plough, the maresha, in order to more efficiently make raised seedbeds and furrows at the time of seed covering - thus reducing water logging and encouraging early planting of improved cereals which could then be followed by a second pulse crop in the same growing season. The most important lessons learned from both ex post impact assessments for the Ethiopian government and research institutions like ILRI is discussed. ILRI's first ex post impact assessment (EPIA) of the BBM TP was undertaken in 1998 (Rutherford et al. 2001. This study quantitatively assessed the returns to the research investment in the Broad Bed Maker technology package using the economic surplus methodology. In terms of improving the welfare of farmers and consumers, the study found that the overall impacts were disappointing. However, some key lessons were learned in terms of constraints to the realization of the potentially significant welfare benefits this technology package offered. The first key lesson in relation to the BBM TP was that adopting and using the package exposed the farm households welfare to considerable risk. The second important lesson from the earlier assessment was that the type and quality of training received by farmers and MoA staff was often insufficient. Third, the human labour requirements and the oxen draught power were usually underestimated. Fourth, the BBM was too heavy if not used at the optimal time-particularly for oxen weakened by lack of feed and disease. Fifth, in the absence of a watershed approach to drainage, increased drainage on one plot often exacerbated water logging and erosion in neighboring plots. Ten years on, this ex post impact assessment was commissioned by ILRI to assess the current role of the same BBM TP in the sustainable utilization of Vertisol soils in Ethiopia. One major finding of the current study was that the BBM that has been extended to farmers by the MoA for the last four years is a single-beam BBM-most similar to a prototype of the double-beam BBM that was developed in the 1980s. No evidence was found of the use of the 1993/94 double-beam BBM that was the focus of the earlier ex post impact assessment so from this point forward, the term BBM refers to the single-beam BBM unless otherwise stated. While the BBM itself has evolved, the purpose for which it is used (i.e. making beds and furrows to allow early planting) has not changed between the two studies

    ILRI in Asia: an assessment of priorities for Asian livestock research and development

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    The purpose of this discussion paper is, firstly, to promote debate amongst potential clients of ILRI's research in South and South-East Asia on what ILRI could do in these regions, in collaboration with the NARS, which will assist the development of the livestock industries and, secondly, to provide advice to the ILRI Board and management on the rational for ILRI involvement in the regions, the nature of that involvement, and the mechanisms and process by which ILRI might maximise the benefits from its investment into research and development, particularly in these regions. The paper looks initially at the economic trends in selected countries in both regions and assesses the likely impact of this on dietary preferences and priorities. Having established the potential demands in the regions for the major livestock products (meat, milk, draft-power, eggs and, to a lesser extent, leather, wool and hair) in the next decade or so, the ways in which deficits in supply can be met from existing systems are assessed. The major constraints to improved production are identified and the role that technologically based research can play in alleviating these constraints is examined. The discussion paper then canvasses options for ILRI's participation, facilitation and leadership in some areas of priority research for the region and some possible mechanisms by which ILRI might achieve such objectives are detailed

    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

    Constraints on anomalous QGC's in e+e−e^{+}e^{-} interactions from 183 to 209 GeV

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    The acoplanar photon pairs produced in the reaction e(+) e(-) - → vvyy are analysed in the 700 pb(-1) of data collected by the ALEPH detector at centre-of-mass energies between 183 and 209 GeV. No deviation from the Standard Model predictions is seen in any of the distributions examined. The resulting 95% C.L. limits set on anomalous QGCs, a(0)(Z), a(c)(Z), a(0)(W) and a(c)(W), are -0.012 lt a(0)(Z)/Lambda(2) lt +0.019 GeV-2, -0.041 lt a(c)(Z)/Lambda(2) lt +0.044 GeV-2, -0.060 lt a(0)(W)/Lambda(2) lt +0.055 GeV-2, -0.099 lt a(c)(W)/Lambda(2) lt +0.093 GeV-2, where Lambda is the energy scale of the new physics responsible for the anomalous couplings

    Measurement of the mass difference between top quark and antiquark in pp collisions at root s=8 TeV

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    Studies of jet quenching using isolated-photon + jet correlations in PbPb and pp collisions at sqrt(s[NN]) = 2.76 TeV

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    Results from the first study of isolated-photon + jet correlations in relativistic heavy ion collisions are reported. The analysis uses data from PbPb collisions at a centre-of-mass energy of 2.76 TeV per nucleon pair corresponding to an integrated luminosity of 150 inverse microbarns recorded by the CMS experiment at the LHC. For events containing an isolated photon with transverse momentum pt(gamma) > 60 GeV and an associated jet with pt(Jet) > 30 GeV, the photon + jet pt imbalance is studied as a function of collision centrality and compared to pp data and PYTHIA calculations at the same collision energy. Using the pt(gamma) of the isolated photon as an estimate of the momentum of the associated parton at production, this measurement allows an unbiased characterisation of the in-medium parton energy loss. For more central PbPb collisions, a significant decrease in the ratio pt(Jet)/pt(gamma) relative to that in the PYTHIA reference is observed. Furthermore, significantly more pt(gamma) > 60 GeV photons in PbPb are observed not to have an associated pt(Jet) > 30 GeV jet, compared to the reference. However, no significant broadening of the photon + jet azimuthal correlation is observed.Comment: Submitted to Physics Letters
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