3,248 research outputs found

    Managing irrigation jointly with farmers: history, present status and future: review of participatory irrigation management in Sri Lanka

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    Agriculture development has been the main strategy for the socioeconomic development in the country since time immemorial, even though its contribution to GDP has been declining recently. Successive governments of Sri Lanka since independence have invested heavily in the irrigated agriculture sector to address the food security concerns of the country. The continuous investment in irrigation was required to address problems such as spatial and temporal variations in monsoonal rainfall in the country, which has a serious negative impact on food production and livelihoods of people. The need for pursuing irrigation development and management has become more important in the country in the face of rapid population growth and increasing food prices in the world market. In this context, managing irrigation schemes for productivity increase is becoming increasingly important and different irrigation management models have also emerged through attempts made in this direction by countries including Sri Lanka, where irrigation plays a leading role in food production and nation development. Farmers’ active involvement in irrigation management, especially operation and maintenance (O&M) and decision-making as well, has been identified as a key requirement to attain productivity goals and the sustainability of irrigation systems. This paper aims at reviewing participatory irrigation management approaches adopted in medium and major irrigation systems in Sri Lanka with a view to identifying their past and present trends and future directions. The review will contribute to an improved understanding by policymakers, managers of irrigation schemes and farmers of the role of participatory irrigation management, its past and present including institutional structures, responsibilities and performance and the directions it should take to meet future challenges as a dynamic institutional mechanism. As all the medium and major irrigation schemes in the country are jointly managed by farmers and government agencies, the inferences drawn from the review would be important for the agencies and farmers alike to introduce necessary changes in their programs to address future needs and requirements.Length: pp.35-63Participatory managementIrrigation managementFarmers organizationsIndicatorsHistoryIrrigation schemes

    An assessment of the Small-Scale Irrigation Management Turnover Program in Indonesia.

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    Irrigation management / Privatization / Small scale systems / Irrigation systems / Water distribution / Performance / Operations / Maintenance / Productivity / Crop yield / Economic impact / Costs / Indonesia

    Predicting the risk to develop preeclampsia in the first trimester combining promoter variant -98A/C of LGALS13 (placental protein 13), Black ethnicity, previous preeclampsia, obesity, and maternal age

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    BACKGROUND: We studied LGALS13 [Placental Protein 13 (PP13)] promoter DNA polymorphisms in preeclampsia (PE) prediction, given PP13’s effects on hypotension, angiogenesis and immunotolerance. METHODS: We retrieved 67 PE (49 term, 18 preterm) cases and 196 matched controls from first trimester plasma samples prospectively collected at King's College Hospital, London. Cell-free DNA was extracted and the four LGALS13 exons were sequenced after PCR amplification. Expression of LGALS13 promoter reporter constructs were determined in BeWo trophoblast-like cells with luciferase assays. RESULTS: A/C genotype in –98 position was the lowest in term PE compared to controls (p<0.032), similar to a South African cohort. Control but not all PE allele frequencies were in Hardy-Weinberg equilibrium (p=0.036). The Odds ratio for term PE calculated from prior risk, the A/A genotype and black ethnicity was 14 (p<0.001). In luciferase assays, the LGALS13 promoter “-98A" variant had 13% (p=0.04) and 26% (p<0.001) lower expression than the "-98C" variant in non-differentiated and differentiated BeWo cells, respectively. After 48-hour differentiation, there was 4.55- fold increase in expression of "-98C" variant versus 3.85-fold of "-98A" variant (p<0.001). CONCLUSION: Lower LGALS13 (PP13) expression by the "-98A/A" genotype appears to impose higher risk to develop PE and could aid in PE prediction

    Journal Staff

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    We present the first measurements of the differential cross section d sigma/dp(T)(gamma) for the production of an isolated photon in association with at least two b-quark jets. The measurements consider photons with rapidities vertical bar y(gamma)vertical bar &lt; 1.0 and transverse momenta 30 &lt; p(T)(gamma) &lt; 200 GeV. The b-quark jets are required to have p(T)(jet) &gt; 15 GeVand vertical bar y(jet)vertical bar &lt; 1.5. The ratio of differential production cross sections for gamma + 2 b-jets to gamma + b-jet as a function of p(T)(gamma) is also presented. The results are based on the proton-antiproton collision data at root s = 1.96 TeV collected with the D0 detector at the Fermilab Tevatron Collider. The measured cross sections and their ratios are compared to the next- to- leading order perturbative QCD calculations as well as predictions based on the k(T)- factorization approach and those from the sherpa and pythia Monte Carlo event generators

    Search for B0→π0π0B^{0}\to \pi^{0}\pi^{0} Decay

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    We have searched for the charmless hadronic decay of B0 mesons into two neutral pions. Using 9.13fb^-1 taken at the Upsilon(4S) with the CLEO detector, we obtain an improved upper limit for the branching fraction BR(B0-->pi0pi0) < 5.7*10^-6 at the 90% confidence level.Comment: pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

    Search for Zgamma events with large missing transverse energy in ppbar collisions at sqrt(s)=1.96 TeV

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    We present the first search for supersymmetry (SUSY) in Zgamma final states with large missing transverse energy using data corresponding to an integrated luminosity of 6.2 fb-1 collected with the D0 experiment in ppbar collisions at sqrt(s)=1.96 TeV. This signature is predicted in gauge-mediated SUSY-breaking models, where the lightest neutralino is the next-to-lightest supersymmetric particle (NLSP) and is produced in pairs, possibly through decay from heavier supersymmetric particles. The NLSP can decay either to a Z boson or a photon and an associated gravitino that escapes detection. We exclude this model at the 95% C.L. for SUSY breaking scales of Lambda < 87 TeV, corresponding to neutralino masses of < 151 GeV.Comment: submitted to Phys. Rev. Let

    Measurement of Leptonic Asymmetries and Top Quark Polarization in ttbar Production

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    We present measurements of lepton (l) angular distributions in ttbar -> W+ b W- b -> l+ nu b l- nubar bbar decays produced in ppbar collisions at a center-of-mass energy of sqrt(s)=1.96TeV, where l is an electron or muon. Using data corresponding to an integrated luminosity of 5.4fb^-1, collected with the D0 detector at the Fermilab Collider, we find that the angular distributions of l- relative to anti-protons and l+ relative to protons are in agreement with each other. Combining the two distributions and correcting for detector acceptance we obtain the forward-backward asymmetry A^l_FB = (5.8 +- 5.1(stat) +- 1.3(syst))%, compared to the standard model prediction of A^l_FB (predicted) = (4.7 +- 0.1)%. This result is further combined with the measurement based on the analysis of the l+jets final state to obtain A^l_FB = (11.8 +- 3.2)%. Furthermore, we present a first study of the top-quark polarization.Comment: submitted versio

    Measurement of the semileptonic charge asymmetry in B0 meson mixing with the D0 detector

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    We present a measurement of the semileptonic mixing asymmetry for B0 mesons, a^d_{sl}, using two independent decay channels: B0 -> mu+D-X, with D- -> K+pi-pi-; and B0 -> mu+D*-X, with D*- -> antiD0 pi-, antiD0 -> K+pi- (and charge conjugate processes). We use a data sample corresponding to 10.4 fb^{-1} of ppbar collisions at sqrt(s) = 1.96 TeV, collected with the D0 experiment at the Fermilab Tevatron collider. We extract the charge asymmetries in these two channels as a function of the visible proper decay length (VPDL) of the B0 meson, correct for detector-related asymmetries using data-driven methods, and account for dilution from charge-symmetric processes using Monte Carlo simulation. The final measurement combines four signal VPDL regions for each channel, yielding a^d_{sl} = [0.68 \pm 0.45 \text{(stat.)} \pm 0.14 \text{(syst.)}]%. This is the single most precise measurement of this parameter, with uncertainties smaller than the current world average of B factory measurements.Comment: Version includes minor textual changes following peer review by journal, most notably the updating of Ref. [21] to reflect the most recent publicatio

    Precise measurement of the top quark mass in the dilepton channel at D0

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    We measure the top quark mass (mt) in ppbar collisions at a center of mass energy of 1.96 TeV using dilepton ttbar->W+bW-bbar->l+nubl-nubarbbar events, where l denotes an electron, a muon, or a tau that decays leptonically. The data correspond to an integrated luminosity of 5.4 fb-1 collected with the D0 detector at the Fermilab Tevatron Collider. We obtain mt = 174.0 +- 1.8(stat) +- 2.4(syst) GeV, which is in agreement with the current world average mt = 173.3 +- 1.1 GeV. This is currently the most precise measurement of mt in the dilepton channel.Comment: 7 pages, 4 figure
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