371 research outputs found

    Effects of Sand Addition to Heavy Saline-Alkali Soil on the Infiltration and Salt Leaching in Hetao Irrigation District, China

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    Proceeding PaperSoil salinity is a matter of great economic and environmental implications. In Hetao Irrigation District, soil salinity limits crop productivity affecting about 69% of its total cultivated land due to natural soil salinisation and salt accumulation caused by irrigation. The goal of this study is to contribute to the alleviation of this problem through the technique of adding wind-sand to the top layer of heavy saline-alkali soil, and to evaluate and analyse their effects on the infiltration and salt leaching. The experiment was carried out on a laboratory scale. Clayey soil with 21 g/kg of salts collected at the Ulat Front Banner site was used. Wind-sand was added to the top 30 cm layer of this soil. The infiltration tests were carried out in plastic columns with 9 cm diameter and 45 cm high, loaded with a soil and wind-sand mixture (from 2% to 30% ratio), supplied by a constant hydraulic head. Soil water samples were collected for 15 days for quantification of the soil salt leaching. A significant increase of the infiltration rate was observed in the first infiltration hour, rising from 1 to 9 mm/h, in response to the addition of 8% and 30% of sandy particles, respectively. The effects of wind-sand in salt leaching were relevant in the top 20 cm layer. After 7 days of infiltration there was a decrease in the salt content in soils with 4%, 8%, and 30% of sand particles added, of 35%, 55%, and 95%, respectively, in relation to the control. In conclusion, the practice of adding sandy particles to the topsoil is a soil melioration method that allows a positive impact on soil infiltration and salt leaching. An addition of 8% of sand seems to be a good choice, as it favours an increase in salt leaching of about 55% after 7 days. These results are encouraging and appeal to field studies to assess the impact on a field-scale system, and the effects of this soil melioration on irrigation, drainage, and agronomic aspectsinfo:eu-repo/semantics/publishedVersio

    Association between autism spectrum disorder and diabetes: systematic review and meta-analysis

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    There is mixed evidence on the link between autism spectrum disorder (ASD) and diabetes. We conducted the first systematic review/meta-analysis on their association. Based on a pre-registered protocol (PROSPERO: CRD42021261114), we searched Pubmed, Ovid, and Web of Science databases up to 6 December 2021, with no language/type of document restrictions. We assessed study quality using the Newcastle-Ottawa Scale (NOS). We included 24 studies (total: 3427,773 individuals; 237,529 with ASD and 92,832 with diabetes) in the systematic review and 20 in the meta-analysis (mean stars number on the NOS: 5.89/10). There was a significant association, albeit characterized by significant heterogeneity, when pooling unadjusted OR (1.535, 95% CI = 1.109-2.126), which remained significant when restricting the analysis to children and type 2 diabetes, but became non-significant when considering adjusted ORs (OR: 1.528, 95% CI = 0.954-2.448). No significant prospective association was found (n = 2) on diabetes predicting ASD (HR: 1.232, 0.826-11.837). Therefore, the association between ASD and diabetes is likely confounded by demographic and clinical factors that should be systematically investigated in future studies

    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

    The Project PTDC/CTE-GIX/098968/2008 - High resolution stratigraphy of the Lower Jurassic organic-rich marine series in the Lusitanian Basin (Portugal): Initial expectations and results

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    Apresenta-se neste trabalho uma caracterização e os principais resultados do Projecto “Estratigrafia de alta resolução das séries marinhas ricas em matéria orgânica do Jurássico Inferior da Bacia Lusitânica”, financiado pela Fundação para a Ciência e Tecnologia (Portugal). Este projecto centrou-se numa análise estratigráfica multidisciplinar baseada num vasto conjunto de parâmetros bióticos e abióticos da sucessão margo-calcária rica em matéria orgânica do Jurássico Inferior da bacia, envolvendo sete objetivos principais: 1. Análise sedimentológica (mineralógica, textural e composicional) e sequencial da sucessão hemipelágica do Jurássico Inferior (Sinemuriano superior–Toarciano); 2. Precisões biostratigráficas a partir do registo de amonóides do intervalo compreendido entre o Sinemuriano superior e o Pliensbaquiano superior; 3. Análise paleontológica e paleoecológica da macrofauna bentónica (fundamentalmente braquiópodes e bivalves); 4. Análise biostratigráfica, taxonómica e paleoecológica da fauna de ostracodos (Sinemuriano–Toarciano); 5. Análise quimiostratigráfica baseada principalmente nos isótopos estáveis de carbono (Sinemuriano–Pliensbaquiano); 6. Análise geoquímica e de petrografia orgânica (carbono orgânico total, pirólise Rock-Eval e biomarcadores) do Sinemuriano–Pliensbaquiano; 7. Análise dos padrões de variação dos raios gama (Sinemuriano–Toarciano.This work presents the main results of the Project ”High resolution stratigraphy of the Lower Jurassic organic-rich marine series in the Lusitanian Basin (Portugal)”, supported by the Portuguese Foundation for Science and Technology. This project was focused on a multidisciplinary stratigraphic analysis based on the study of a range of biotic and abiotic parameters of the Lower Jurassic marl–limestone succession rich in organic matter, embracing seven main objectives: 1. Sedimentological (mineralogical, textural and compositional) and sequential analysis of the whole Lower Jurassic hemipelagic succession (Upper Sinemurian–Toarcian); 2. Ammonite biostratigraphic precisions of the Upper Sinemurian and Upper Pliensbachian; 3. Palaeontological and palaeoecological analysis of the benthic macrofauna (especially brachiopods and bivalves); 4. Biostratigraphical, taxonomic and palaeoecological analysis of the ostracod fauna (Sinemurian–Toarcian); 5. Chemostratigraphic analysis based mainly on carbon stable isotopes (Sinemurian–Pliensbachian); 6. Organic geochemical and petrographic analysis (total organic carbon, palynofacies, Rock-Eval pyrolysis and biomarkers) of the Sinemurian–Pliensbachian; 7. Vertical variation patterns of gamma-ray analysis (Sinemurian–Toarcian). Besides the new results in each specific scientific domain (for example, biostratigraphy, palaeoecology, sedimentology, sequence stratigraphy and cyclicity, chemostratigraphy and organic geochemistry), the integration of all data, in several cases at highresolution level, allows emphasizing the achievement of two main transverse goals: the improvement of the stratigraphy and sedimentary knowledge of the Lower Jurassic series of western Iberia margin, with implications in the palaoenvironmental and palaeoceanographic interpretations of the Tethyan pre-Atlantic basins dynamics and global correlation; taking into consideration the huge number of organic geochemical parameters analyzed, the results of this research contributed significantly to understand the role of the different Sinemurian and Pliensbachian organic-rich intervals as potential hydrocarbon generation sources (quality of organic matter and maturation).Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEFondo Europeo de Desarrollo Regional (COMPETE- FEDER)Fundação para a Ciência e a Tecnologia (FCT)pu

    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
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