324 research outputs found

    Micronutrient Distributions in the East Siberian and Laptev Seas during summer 1963

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    Discusses phosphate, silicate, nitrate, temperature and salinity (T/S) data collected at 140 oceanographic stations occupied by the USCGC Northwind in these seas 7 Aug - 10 Sept 1963, cf No. 92559. These shallow seas deepen gradually toward the shelf edge, the East Siberian toward the E. Precipitation in the excess of evaporation should add ~50 km³/yr of fresh-water to the area; runoff from the seven rivers is ~250 km³/yr for the E Siberian and ~700 km³/yr for the Laptev Sea. Ice ~2 m thick forms in winter, summer melt is ~1 m, the difference compensated by net ice drift out of the area. Surface currents reduce the ice cover near shore in summer, but there is close-pack ice adjacent to Taymyr Peninsula. Annual and seasonal variations in air temperature, wind regime and river runoff obviate steady-state currents and T/S in the region. Silicate concentrations in the surface layer were almost always 5ug-at/liter, those of phosphate or nitrate or both were often so low as to suggest nutrient limitation of phytoplankton production. The nutrients in both seas are compared and discussed in relation to the intense stratification and turbidity of the waters, ice cover, and river discharge. The micronutrient distributions appear to be influenced mainly by summer phytoplankton bloom, respiratory processes, outflow of the Lena, and the different origins of the high-salinity waters found in the two seas.Distribution des microéléments nutritifs dans la mer de Sibérie orientale et dans la mer de Laptev au cours de l'été 1963. L'éclosion estivale du plancton, les processus respiratoires, la décharge du fleuve Léna et les origines diverses des eaux de haute salinité semblent être les facteurs dominants qui influencent la distribution des microéléments nutritifs observée dans la mer de Sibérie orientale et dans la mer de Laptev

    Increased ERK signalling promotes inflammatory signalling in primary airway epithelial cells expressing Z Îą1-antitrypsin.

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    Overexpression of Z Îą1-antitrypsin is known to induce polymer formation, prime the cells for endoplasmic reticulum stress and initiate nuclear factor kappa B (NF-ÎşB) signalling. However, whether endogenous expression in primary bronchial epithelial cells has similar consequences remains unclear. Moreover, the mechanism of NF-ÎşB activation has not yet been elucidated. Here, we report excessive NF-ÎşB signalling in resting primary bronchial epithelial cells from ZZ patients compared with wild-type (MM) controls, and this appears to be mediated by mitogen-activated protein/extracellular signal-regulated kinase, EGF receptor and ADAM17 activity. Moreover, we show that rather than being a response to protein polymers, NF-ÎşB signalling in airway-derived cells represents a loss of anti-inflammatory signalling by M Îą1-antitrypsin. Treatment of ZZ primary bronchial epithelial cells with purified plasma M Îą1-antitrypsin attenuates this inflammatory response, opening up new therapeutic options to modulate airway inflammation in the lung

    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 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

    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
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