9 research outputs found

    Alignment of the ALICE Inner Tracking System with cosmic-ray tracks

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    37 pages, 15 figures, revised version, accepted by JINSTALICE (A Large Ion Collider Experiment) is the LHC (Large Hadron Collider) experiment devoted to investigating the strongly interacting matter created in nucleus-nucleus collisions at the LHC energies. The ALICE ITS, Inner Tracking System, consists of six cylindrical layers of silicon detectors with three different technologies; in the outward direction: two layers of pixel detectors, two layers each of drift, and strip detectors. The number of parameters to be determined in the spatial alignment of the 2198 sensor modules of the ITS is about 13,000. The target alignment precision is well below 10 micron in some cases (pixels). The sources of alignment information include survey measurements, and the reconstructed tracks from cosmic rays and from proton-proton collisions. The main track-based alignment method uses the Millepede global approach. An iterative local method was developed and used as well. We present the results obtained for the ITS alignment using about 10^5 charged tracks from cosmic rays that have been collected during summer 2008, with the ALICE solenoidal magnet switched off.Peer reviewe

    Anchored fibrous chrysotile silica and its ability in using nitrogen basic centers on cation complexing from aqueous solution

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    Amorphous silica gel obtained through natural chrysotile was lixiviated with hydrochloric acid, which was chemically modified with organosilanes (H3CO)(3)SiR, where R corresponds to the organic moieties -CH2CH2CH2NH2 and -CH2CH2CH2NHCH2CH2NH2, yielding solids named SIL1 and SIL2. These anchored silicas showed 2.14 +/- 0.05 and 1.90 +/- 0.04 mmol g(-1) of attached amino groups on surfaces SIL1 and SIL2, respectively. The isotherms of adsorption data were obtained by batchwise process, whose values were adjusted to a modified Langmuir equation. The maximum adsorption capacity showed the sequence for copper and cobalt as 1.02, 0.35 mmol g(-1) on SIL2 and 0.71, 0.26 mmol g(-1) on SIL1, respectively. By using calorimetric titration, the enthalpy change of the adsorption process was 18.77 +/- 0.75 and -43.29 +/- 1.08 kJ mol(-1) for copper, 12.70 +/- 0.57 and -169.3 +/- 1.23 kJ mol(-1) for cobalt on SIL1 and SIL2, respectively. Negative Gibbs free energy values are in agreement with the spontaneity of the proposed reactions involving both divalent cations, when complexed by basic amino groups attached to pendant chain covalently bonded to the inorganic surface. (C) 2003 Elsevier B.V. All rights reserved.22741699859

    Epidemiological characteristics, practice of ventilation, and clinical outcome in patients at risk of acute respiratory distress syndrome in intensive care units from 16 countries (PRoVENT): an international, multicentre, prospective study

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    Background Scant information exists about the epidemiological characteristics and outcome of patients in the intensive care unit (ICU) at risk of acute respiratory distress syndrome (ARDS) and how ventilation is managed in these individuals. We aimed to establish the epidemiological characteristics of patients at risk of ARDS, describe ventilation management in this population, and assess outcomes compared with people at no risk of ARDS. Methods PRoVENT (PRactice of VENTilation in critically ill patients without ARDS at onset of ventilation) is an international, multicentre, prospective study undertaken at 119 ICUs in 16 countries worldwide. All patients aged 18 years or older who were receiving mechanical ventilation in participating ICUs during a 1-week period between January, 2014, and January, 2015, were enrolled into the study. The Lung Injury Prediction Score (LIPS) was used to stratify risk of ARDS, with a score of 4 or higher defining those at risk of ARDS. The primary outcome was the proportion of patients at risk of ARDS. Secondary outcomes included ventilatory management (including tidal volume [VT] expressed as mL/kg predicted bodyweight [PBW], and positive end-expiratory pressure [PEEP] expressed as cm H2O), development of pulmonary complications, and clinical outcomes. The PRoVENT study is registered at ClinicalTrials.gov, NCT01868321. The study has been completed. Findings Of 3023 patients screened for the study, 935 individuals fulfilled the inclusion criteria. Of these critically ill patients, 282 were at risk of ARDS (30%, 95% CI 27â33), representing 0·14 cases per ICU bed over a 1-week period. VTwas similar for patients at risk and not at risk of ARDS (median 7·6 mL/kg PBW [IQR 6·7â9·1] vs 7·9 mL/kg PBW [6·8â9·1]; p=0·346). PEEP was higher in patients at risk of ARDS compared with those not at risk (median 6·0 cm H2O [IQR 5·0â8·0] vs 5·0 cm H2O [5·0â7·0]; p<0·0001). The prevalence of ARDS in patients at risk of ARDS was higher than in individuals not at risk of ARDS (19/260 [7%] vs 17/556 [3%]; p=0·004). Compared with individuals not at risk of ARDS, patients at risk of ARDS had higher in-hospital mortality (86/543 [16%] vs 74/232 [32%]; p<0·0001), ICU mortality (62/533 [12%] vs 66/227 [29%]; p<0·0001), and 90-day mortality (109/653 [17%] vs 88/282 [31%]; p<0·0001). VTdid not differ between patients who did and did not develop ARDS (p=0·471 for those at risk of ARDS; p=0·323 for those not at risk). Interpretation Around a third of patients receiving mechanical ventilation in the ICU were at risk of ARDS. Pulmonary complications occur frequently in patients at risk of ARDS and their clinical outcome is worse compared with those not at risk of ARDS. There is potential for improvement in the management of patients without ARDS. Further refinements are needed for prediction of ARDS. Funding None

    Midrapidity antiproton-to-proton ratio in pp collisons root s=0.9 and 7 TeV measured by the ALICE experiment

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    The ratio of the yields of antiprotons to protons in pp collisions has been measured by the ALICE experiment at root s = 0.9 and 7 TeV during the initial running periods of the Large Hadron Collider. The measurement covers the transverse momentum interval 0.45 < p(t) < 1.05 GeV/c and rapidity vertical bar y vertical bar < 0.5. The ratio is measured to be R-vertical bar y vertical bar<0.5 = 0.957 +/- 0.006(stat) +/- 0.0014(syst) at 0.9 Tev and R-vertical bar y vertical bar<0.5 = 0.991 +/- 0.005 +/- 0.014(syst) at 7 TeV and it is independent of both rapidity and transverse momentum. The results are consistent with the conventional model of baryon-number transport and set stringent limits on any additional contributions to baryon-number transfer over very large rapidity intervals in pp collisions

    Two-pion Bose-Einstein correlations in pp collisions at root s=900 GeV

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    We report on the measurement of two-pion correlation functions from pp collisions at root s = 900 GeV performed by the ALICE experiment at the Large Hadron Collider. Our analysis shows an increase of the Hanbury Brown-Twiss radius with increasing event multiplicity, in line with other measurements done in particle- and nuclear collisions. Conversely, the strong decrease of the radius with increasing transverse momentum, as observed at the Relativistic Heavy Ion Collider and at Tevatron, is not manifest in our data

    Gamma-aminobutyric acid uptake and the termination of inhibitory synaptic potentials in the rat hippocampal slice.

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    Intracellular recordings were made from CA1 pyramidal cells in the rat hippocampal slice to study the processes that influence the time course of inhibitory post-synaptic potentials (i.p.s.p.s) mediated by gamma-aminobutyric acid (GABA), and conductance changes evoked by ionophoretically applied GABA. The GABA-uptake inhibitors, nipecotic acid and cis-4-OH-nipecotic acid (1 mM), greatly prolonged conductance increases associated with both hyperpolarizing and depolarizing responses to ionophoretically applied GABA. In contrast to their effects on GABA-evoked conductances, uptake inhibitors only slightly prolonged antidromically evoked i.p.s.p.s. Their primary effect occurred after the i.p.s.p. had decayed to 5-30% of its peak. 4-OH-isonipecotic acid, a nipecotic acid analogue that does not inhibit GABA uptake, did not prolong i.p.s.p.s or ionophoretically evoked conductance changes. Sodium pentobarbitone (100 microM), a drug that prolongs the open time of GABA-activated chloride channels, potentiated both i.p.s.p.s and responses to ionophoretically applied GABA. Whereas pentobarbitone also prolonged i.p.s.p.s, it did not prolong responses to ionophoretically applied GABA. The prolongation of i.p.s.p.s by pentobarbitone occurred equally in both the early and late phases of the i.p.s.p., in contrast to the effects of GABA-uptake inhibitors. I.p.s.p.s did not usually decay exponentially. The observation that uptake inhibitors prolonged the late but not the early decay phase of the i.p.s.p., together with the previous finding that the conductance change persists for the duration of the i.p.s.p., indicate that GABA is present in the synapse throughout much of the i.p.s.p. These data suggest that diffusion of GABA out of the synapse, a non-exponential process, is an important determinant of the i.p.s.p. decay time course. Increasing the extracellular potassium concentration from 3.5 to 8.5 mM resulted in spontaneously occurring, synchronous burst firing of pyramidal cells. Cis-4-OH-nipecotic acid significantly reduced the number and amplitude of extracellularly recorded population spikes within each burst. We conclude that diffusion, channel open time and GABA uptake all influence the time course of GABA-mediated i.p.s.p.s. The time course of a single, brief i.p.s.p. is determined predominantly by post-synaptic channel kinetics and diffusion of GABA out of the synapse, whereas the inhibition produced by prolonged synaptic bursts or relatively long application of exogenous GABA can be markedly influenced by GABA uptake.(ABSTRACT TRUNCATED AT 400 WORDS

    Midrapidity Antiproton-to-Proton Ratio in pp Collisons root s=0.9 and 7 TeV Measured by the ALICE Experiment

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    The ratio of the yields of antiprotons to protons in pp collisions has been measured by the ALICE experiment at root s = 0.9 and 7 TeV during the initial running periods of the Large Hadron Collider. The measurement covers the transverse momentum interval 0.45 < p(t) < 1.05 GeV/c and rapidity vertical bar y vertical bar < 0.5. The ratio is measured to be R(vertical bar y vertical bar<0.5) = 0.957 +/- 0.006(stat) +/- 0.0014(syst) at 0.9 Tev and R(vertical bar y vertical bar<0.5) = 0.991 +/- 0.005 +/- 0.014(syst) at 7 TeV and it is independent of both rapidity and transverse momentum. The results are consistent with the conventional model of baryon-number transport and set stringent limits on any additional contributions to baryon-number transfer over very large rapidity intervals in pp collisions

    Midrapidity Antiproton-to-Proton Ratio in pp Collisons root s=0.9 and 7 TeV Measured by the ALICE Experiment

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    Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)The ratio of the yields of antiprotons to protons in pp collisions has been measured by the ALICE experiment at root s = 0.9 and 7 TeV during the initial running periods of the Large Hadron Collider. The measurement covers the transverse momentum interval 0.45 < p(t) < 1.05 GeV/c and rapidity vertical bar y vertical bar < 0.5. The ratio is measured to be R-vertical bar y vertical bar<0.5 = 0.957 +/- 0.006(stat) +/- 0.0014(syst) at 0.9 Tev and R-vertical bar y vertical bar<0.5 = 0.991 +/- 0.005 +/- 0.014(syst) at 7 TeV and it is independent of both rapidity and transverse momentum. The results are consistent with the conventional model of baryon-number transport and set stringent limits on any additional contributions to baryon-number transfer over very large rapidity intervals in pp collisions.1057Calouste Gulbenkian Foundation from LisbonConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Financiadora de Estudos e Projetos (FINEP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)National Natural Science Foundation of China (NSFC)Chinese Ministry of Education (CMOE)Ministry of Science and Technology of China (MSTC)Ministry of Education and Youth of the Czech RepublicDanish Natural Science Research CouncilCarlsberg FoundationDanish National Research FoundationThe European Research CouncilHelsinki Institute of PhysicsAcademy of FinlandFrench CNRS-IN2P3Region Pays de LoireRegion AlsaceRegion AuvergneCEA, FranceGerman BMBFHelmholtz AssociationHungarian OTKANational Office for Research and Technology (NKTH)Department of Atomic EnergyDepartment of Science and Technology of the Government of IndiaIstituto Nazionale di Fisica Nucleare (INFN) of ItalyMEXT, JapanJoint Institute for Nuclear Research, DubnaKorea Foundation for International Cooperation of Science and Technology (KICOS)CONACYTDGAPA, MexicoALFA-ECHELEN Program (High-Energy physics Latin-American-European Network)Stichting voor Fundamenteel Onderzoek der Materie (FOM)Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO), The NetherlandsResearch Council of Norway (NFR)Polish Ministry of Science and Higher EducationNational Authority for Scientific Research-NASR (Autontatea Nationala pentru Cercetare Stiintifica-ANCS)Federal Agency of Science of the Ministry of Education and Science of Russian FederationInternational Science and Technology CenterRussian Academy of SciencesRussian Federal Agency of Atomic EnergyRussian Federal Agency for Science and InnovationsCERN-INTASMinistry of Education of SlovakiaCIEMATEELAMinisterio de Educacion y Ciencia of SpainXunta de Galicia (Conselleria de Educacion)CEADENCubaenergia, CubaIAEA (International Atomic Energy Agency)Swedish Reseach CouncilKnut & Alice Wallenberg FoundationUkraine Ministry of Education and ScienceUnited Kingdom Science and Technology Facilities Council (STFC)The United States Department of EnergyUnited States National Science Foundation, State of TexasSwiss Fonds Kidagan, ArmeniaUnited States National Science Foundation, the State of OhioConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP
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