263 research outputs found

    Coccolithophorids in polar waters: Pappomonas spp. revisited

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    A contingent of weakly calcified coccolithophorid genera and species were described from polar regions almost 40 years ago. In the interim period a few additional findings have been reported enlarging the realm of some of the species. The genus Pappomonas is revisited here with the purpose of providing, based on additional sampling from both polar regions, an update on species morphology, life history aspects and biogeography that can serve as a reference for the future. The examination of a substantial number of cells unequivocally supports the elevation to species level of P. borealis stat. nov. (previously referred to as P. flabellifera var. borealis) as a separate taxon which is different from P. flabellifera in a number of critical morphological features. Additional evidence in favour of linking P. virgulosa and Bala­niger balticus in a shared life history in combination with significant differences in coccolith morphology between the Pappomonas type species (P. flabellifera) and P. virgulosa has prompted us to synonymise Balaniger balticus with Pappomonas virgulosa, while informally keeping the names of the phases as Balaniger virgulosa HET (= Pappomonas virgulosa phase) and Balaniger virgulosa HOL (= Balaniger balticus phase). A new species, Pappomonas garrisonii sp. nov. is described to accommodate Antarctic material from the Weddell Sea. While fitting into the Pappomonas generic concept, the species adds new dimensions to the overall appearance of the coccolith armour of the cell and emphasizes the close relationship between species of Pappomonas and Papposphaera

    Coastal observatories for monitoring of fish behaviour and their responses to environmental changes

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    The inclusion of behavioral components in the analysis of a community can be of paramount importance in marine ecology. Diel (i.e., 24-h based), seasonal activity rhythms, or longer durational in behavioral responses can result in shifts in populations, and therefore on measurable abundances. Here, we review the value of developing cabled video observatory technology for the remote, long-term, and high-frequency monitoring of fish and their environments in coastal temperate areas. We provide details on the methodological requirements and constraints for the appropriate measurement of fish behavior over various seasonal scales (24 h, seasonal, annual) with camera systems mounted at fixed observatory locations. We highlight the importance of using marine sensors to simultaneously collect relevant environmental data in parallel to image data acquisition. Here we present multiparametric video, oceanographic, and meteorological data collected from the Mediterranean observatory platform, OBSEA (www.​obsea.​es; 20 m water depth). These data are reviewed in relation to ongoing and future developments of cabled observatory science. Two key approaches for the future improvement of cabled observatory technology are: (1) the application of Artificial Intelligence to aid in the analysis of increasingly large, complex, and highly interrelated biological and environmental data sets, and (2) the development of geographical observational networks to enable the reliable spatial analysis of observed populations over extended distances

    Glycemic control and long-acting insulin analog utilization in patients with type 2 diabetes

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    Introduction: The objective was to compare glycemic control, insulin utilization, and body weight in patients with type 2 diabetes (T2D) initiated on insulin detemir (IDet) or insulin glargine (IGlar) in a real-life setting in the Netherlands. Methods: Insulin-naïve patients with T2D, starting treatment with IDet or IGlar between January 1, 2004 and June 30, 2008, were selected from the PHARMO data network. Glycemic control (hemoglobin A1c [HbA1c]), target rates (HbA1c <7%), daily insulin dose, and weight gain were analyzed comparing IDet and IGlar for patients with available HbA1c levels both at baseline and at 1-year follow-up. Analysis of all eligible patients (AEP) and a subgroup of patients without treatment changes (WOTC) in the follow-up period were adjusted for patient characteristics, propensity scores, and baseline HbA1c. Results: A total of 127 IDet users and 292 IGlar users were included in the WOTC analyses. The mean HbA1c dropped from 8.4%-8.6% at baseline to 7.4% after 1 year. Patients at HbA1c goal increased from 9% at baseline to 32% for IDet and 11% to 35% for IGlar, which was not significantly different (OR 0.75, 95% CI 0.46, 1.24). Weight gain (n=90) was less among IDet users (+0.4kg) than among IGlar users (+1.1kg), albeit not significant. The AEP analysis (252 IDet

    Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

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    A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

    Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

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    Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02

    Measurement of the branching ratio Γ(Λb⁰ → ψ(2S)Λ0)/Γ(Λb⁰ → J/ψΛ0) with the ATLAS detector

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    An observation of the Λb0ψ(2S)Λ0\Lambda_b^0 \rightarrow \psi(2S) \Lambda^0 decay and a comparison of its branching fraction with that of the Λb0J/ψΛ0\Lambda_b^0 \rightarrow J/\psi \Lambda^0 decay has been made with the ATLAS detector in proton--proton collisions at s=8\sqrt{s}=8\,TeV at the LHC using an integrated luminosity of 20.620.6\,fb1^{-1}. The J/ψJ/\psi and ψ(2S)\psi(2S) mesons are reconstructed in their decays to a muon pair, while the Λ0pπ\Lambda^0\rightarrow p\pi^- decay is exploited for the Λ0\Lambda^0 baryon reconstruction. The Λb0\Lambda_b^0 baryons are reconstructed with transverse momentum pT>10p_{\rm T}>10\,GeV and pseudorapidity η<2.1|\eta|<2.1. The measured branching ratio of the Λb0ψ(2S)Λ0\Lambda_b^0 \rightarrow \psi(2S) \Lambda^0 and Λb0J/ψΛ0\Lambda_b^0 \rightarrow J/\psi \Lambda^0 decays is Γ(Λb0ψ(2S)Λ0)/Γ(Λb0J/ψΛ0)=0.501±0.033(stat)±0.019(syst)\Gamma(\Lambda_b^0 \rightarrow \psi(2S)\Lambda^0)/\Gamma(\Lambda_b^0 \rightarrow J/\psi\Lambda^0) = 0.501\pm 0.033 ({\rm stat})\pm 0.019({\rm syst}), lower than the expectation from the covariant quark model.Comment: 12 pages plus author list (28 pages total), 5 figures, 1 table, published on Physics Letters B 751 (2015) 63-80. All figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/BPHY-2013-08

    Measurement of the View the tt production cross-section using eμ events with b-tagged jets in pp collisions at √s = 13 TeV with the ATLAS detector

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    This paper describes a measurement of the inclusive top quark pair production cross-section (σtt¯) with a data sample of 3.2 fb−1 of proton–proton collisions at a centre-of-mass energy of √s = 13 TeV, collected in 2015 by the ATLAS detector at the LHC. This measurement uses events with an opposite-charge electron–muon pair in the final state. Jets containing b-quarks are tagged using an algorithm based on track impact parameters and reconstructed secondary vertices. The numbers of events with exactly one and exactly two b-tagged jets are counted and used to determine simultaneously σtt¯ and the efficiency to reconstruct and b-tag a jet from a top quark decay, thereby minimising the associated systematic uncertainties. The cross-section is measured to be: σtt¯ = 818 ± 8 (stat) ± 27 (syst) ± 19 (lumi) ± 12 (beam) pb, where the four uncertainties arise from data statistics, experimental and theoretical systematic effects, the integrated luminosity and the LHC beam energy, giving a total relative uncertainty of 4.4%. The result is consistent with theoretical QCD calculations at next-to-next-to-leading order. A fiducial measurement corresponding to the experimental acceptance of the leptons is also presented

    Search for TeV-scale gravity signatures in high-mass final states with leptons and jets with the ATLAS detector at sqrt [ s ] = 13TeV

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    A search for physics beyond the Standard Model, in final states with at least one high transverse momentum charged lepton (electron or muon) and two additional high transverse momentum leptons or jets, is performed using 3.2 fb−1 of proton–proton collision data recorded by the ATLAS detector at the Large Hadron Collider in 2015 at √s = 13 TeV. The upper end of the distribution of the scalar sum of the transverse momenta of leptons and jets is sensitive to the production of high-mass objects. No excess of events beyond Standard Model predictions is observed. Exclusion limits are set for models of microscopic black holes with two to six extra dimensions
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