1,612 research outputs found

    Increasing pattern recognition accuracy for chemical sensing by evolutionary based drift compensation

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    Artificial olfaction systems, which mimic human olfaction by using arrays of gas chemical sensors combined with pattern recognition methods, represent a potentially low-cost tool in many areas of industry such as perfumery, food and drink production, clinical diagnosis, health and safety, environmental monitoring and process control. However, successful applications of these systems are still largely limited to specialized laboratories. Sensor drift, i.e., the lack of a sensor's stability over time, still limits real in dustrial setups. This paper presents and discusses an evolutionary based adaptive drift-correction method designed to work with state-of-the-art classification systems. The proposed approach exploits a cutting-edge evolutionary strategy to iteratively tweak the coefficients of a linear transformation which can transparently correct raw sensors' measures thus mitigating the negative effects of the drift. The method learns the optimal correction strategy without the use of models or other hypotheses on the behavior of the physical chemical sensors

    210Pb-derived history of PAHs and PCBs accumulationin sediments of a tropical inner Lagoon (Las Matas,Gulf of Mexico) near a major oil refinery

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    Concentrations of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) were measured in a sediment core from the tropical freshwater inner lagoon of Las Matas, near the petroleum industrial area of MinatitlaÂŽn-Coatzacoalcos, in the Gulf of Mexico. A 210Pb-derived chronology was used to reconstruct the historical PAH and PCB accumulation in the site during one century (1906–2005). Both geochemical and sedimentological data indicated that a major change occurred in 1947 ± 4, including a shift to coarser sediments and a significant decrease of Al, Li, Fe, organic C and total N contents. This was likely due to the changes in hydrology caused by the confinement of Las Matas Lagoon due to the construction of the Trans-Isthmus road in 1946. PAHs in these samples show relatively low concentrations (259–1176 ng g1), and the congener relative abundances indicate the influence of pyrogenic (petroleum combustion) sources. Total PCB concentrations in the sediments ranged from 24 to 77 ng g1, and are composed by low chlorinated PCBs, with 3- and 4-CB as the prevalent species (51–65% and 29–40%, respectively). PAHs and PCBs were detected at depths corresponding to the early 1900s, when MinatitlaÂŽn refinery started operations, although their time evolution appears to be influenced by different accumulation processes. The PCB background is most likely produced by the combustion of natural organic matter, and an industrial contribution can be recognized when normalizing with OC contents. We concluded that atmospheric deposition is the most significant source of PAHs and PCBs for this water body. This study also provided evidence of the alteration of the wetlands surrounding this industrial area due to urbanization; the fragmentation and alteration of Las Matas Lagoon hydrology contributes to the gradual loss of the wetlands in the zone

    A larger brown fat volume and lower radiodensity are related to a greater cardiometabolic risk, especially in young men

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    Objectives: Brown adipose tissue (BAT) is important in the maintenance of cardiometabolic health in rodents. Recent reports appear to suggest the same in humans, although if this is true remains elusive partly because of the methodological bias that affected previous research. This cross-sectional work reports the relationships of cold-induced BAT volume, activity (peak standardized uptake, SUVpeak), and mean radiodensity (an inverse proxy of the triacylglycerols content) with the cardiometabolic and inflammatory profile of 131 young adults, and how these relationships are influenced by sex and body weight.Design: This is a cross-sectional study.Methods: Subjects underwent personalized cold exposure for 2 h to activate BAT, followed by static F-18-fluorodeoxyglucose PET-CT scanning to determine BAT variables. Information on cardiometabolic risk (CMR) and inflammatory markers was gathered, and a CMR score and fatty liver index (FLI) were calculated.Results: In men, BAT volume was positively related to homocysteine and liver damage markers concentrations (independently of BMI and seasonality) and the FLI (all P 0.05).Conclusions: A larger BAT volume and a lower BAT mean radiodensity are related to a higher CMR, especially in young men, which may support that BAT acts as a compensatory organ in states of metabolic disruption.</p

    No evidence of brown adipose tissue activation after 24 weeks of supervised exercise training in young sedentary adults in the ACTIBATE randomized controlled trial

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    Exercise modulates both brown adipose tissue (BAT)metabolismand white adipose tissue (WAT) browning in murine models. Whether this is true in humans, however, has remained unknown. An unblinded randomized controlled trial (ClinicalTrials.gov ID: NCT02365129) was therefore conducted to study the effects of a 24-week supervised exercise intervention, combining endurance and resistance training, on BAT volume and activity (primary outcome). The study was carried out in the Sport and Health University Research Institute and the Virgen de las Nieves University Hospital of the University of Granada (Spain). One hundred and forty-five young sedentary adults were assigned to either (i) a control group (no exercise, n = 54), (ii) a moderate intensity exercise group (MOD-EX, n = 48), or (iii) a vigorous intensity exercise group (VIG-EX n = 43) by unrestricted randomization. No relevant adverse events were recorded. 97 participants (34 men, 63 women) were included in the final analysis (Control; n = 35, MOD-EX; n=31, and VIG-EX; n=31).We observed no changes in BAT volume (Δ Control: −22.2 ± 52.6ml; Δ MOD-EX: −15.5 ± 62.1ml, Δ VIG-EX: −6.8 ± 66.4 ml; P = 0.771) or 18F-fluorodeoxyglucose uptake (SUVpeak Δ Control: −2.6 ± 3.1ml; Δ MOD-EX: −1.2 ± 4.8, Δ VIG-EX: −2.2 ± 5.1; p = 0.476) in either the control or the exercise groups. Thus, we did not find any evidence of an exercise-induced change on BAT volume or activity in young sedentary adults.Spanish Government PI13/01393Retos de la Sociedad DEP2016-79512-R PTA-12264IEuropean CommissionSpanish Government FPU13/04365 FPU14/04172 FPU15/04059 FPU16/03653 FPU19/01609Consejo Nacional de Ciencia y Tecnologia (CONACyT) 440575Fundacion Iberoamericana de Nutricion (FINUT)Redes Tematicas de Investigacion Cooperativa RETIC Red SAMID RD16/0022AstraZenecaUniversity of Granada Plan Propio de Investigacion 2016 -Excellence actions: Unit of Excellence on Exercise and Health (UCEES)Plan Propio de Investigacion 2018 -Programa Contratos-PuentePrograma Perfecionamiento de DoctoresJunta de Andalucia Consejeria de Conocimiento, Investigacion y Universidades (ERDF) SOMM17/6107/UGRJunta de Andalucia P18-RT-4455Fundacion Alfonso Martin EscuderoMaria Zambrano fellowship by the Ministerio de Universidades y la Union Europea-NextGenerationEU RR_C_2021_04Novo Nordisk FoundationNovocure Limited NNF18OC003239

    Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC

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    The uncertainty on the calorimeter energy response to jets of particles is derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the calorimeter response to single isolated charged hadrons is measured and compared to the Monte Carlo simulation using proton-proton collisions at centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009 and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter response to specific types of particles (positively and negatively charged pions, protons, and anti-protons) is measured and compared to the Monte Carlo predictions. Finally, the jet energy scale uncertainty is determined by propagating the response uncertainty for single charged and neutral particles to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3% for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table, submitted to European Physical Journal

    Standalone vertex ïŹnding in the ATLAS muon spectrometer

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    A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011

    Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC

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    Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H →γ Îł, H → Z Z∗ →4l and H →W W∗ →lÎœlÎœ. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV, corresponding to an integrated luminosity of about 25 fb−1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined ïŹts probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson

    Measurement of the top quark pair cross section with ATLAS in pp collisions at √s=7 TeV using final states with an electron or a muon and a hadronically decaying τ lepton

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    A measurement of the cross section of top quark pair production in proton-proton collisions recorded with the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy of 7 TeV is reported. The data sample used corresponds to an integrated luminosity of 2.05 fb -1. Events with an isolated electron or muon and a τ lepton decaying hadronically are used. In addition, a large missing transverse momentum and two or more energetic jets are required. At least one of the jets must be identified as originating from a b quark. The measured cross section, σtt-=186±13(stat.)±20(syst.)±7(lumi.) pb, is in good agreement with the Standard Model prediction

    Measurement of the top quark-pair production cross section with ATLAS in pp collisions at \sqrt{s}=7\TeV

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    A measurement of the production cross-section for top quark pairs(\ttbar) in pppp collisions at \sqrt{s}=7 \TeV is presented using data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in two different topologies: single lepton (electron ee or muon Ό\mu) with large missing transverse energy and at least four jets, and dilepton (eeee, ΌΌ\mu\mu or eΌe\mu) with large missing transverse energy and at least two jets. In a data sample of 2.9 pb-1, 37 candidate events are observed in the single-lepton topology and 9 events in the dilepton topology. The corresponding expected backgrounds from non-\ttbar Standard Model processes are estimated using data-driven methods and determined to be 12.2±3.912.2 \pm 3.9 events and 2.5±0.62.5 \pm 0.6 events, respectively. The kinematic properties of the selected events are consistent with SM \ttbar production. The inclusive top quark pair production cross-section is measured to be \sigmattbar=145 \pm 31 ^{+42}_{-27} pb where the first uncertainty is statistical and the second systematic. The measurement agrees with perturbative QCD calculations.Comment: 30 pages plus author list (50 pages total), 9 figures, 11 tables, CERN-PH number and final journal adde

    Measurement of the flavour composition of dijet events in pp collisions at root s=7 TeV with the ATLAS detector

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    This paper describes a measurement of the flavour composition of dijet events produced in pp collisions at &#8730;s=7 TeV using the ATLAS detector. The measurement uses the full 2010 data sample, corresponding to an integrated luminosity of 39 pb−1. Six possible combinations of light, charm and bottom jets are identified in the dijet events, where the jet flavour is defined by the presence of bottom, charm or solely light flavour hadrons in the jet. Kinematic variables, based on the properties of displaced decay vertices and optimised for jet flavour identification, are used in a multidimensional template fit to measure the fractions of these dijet flavour states as functions of the leading jet transverse momentum in the range 40 GeV to 500 GeV and jet rapidity |y|&#60;2.1. The fit results agree with the predictions of leading- and next-to-leading-order calculations, with the exception of the dijet fraction composed of bottom and light flavour jets, which is underestimated by all models at large transverse jet momenta. The ability to identify jets containing two b-hadrons, originating from e.g. gluon splitting, is demonstrated. The difference between bottom jet production rates in leading and subleading jets is consistent with the next-to-leading-order predictions
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