3,364 research outputs found

    Fermi-Dirac Correlations in Z^{0} \to ppX at LEP

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    The DELPHI and ALEPH experiments have released new results of the Fermi-Dirac correlations for pp (\bar{p} \bar{p}) and Bose-Einstein correlations for K^0_s K^0_s. Both experiments measure very small source radius for protons R \sim 0.1 fm. The source dimension for K^0_s K^0_s is in agreement with the previous measurements for K^+ K^-, K^0_s K^0_s. These results, together with earlier LEP measurements, establish the dependence of the correlation radius on the hadron mass. This paper discusses some of the attempts to describe this phenomenon.Comment: Contributed paper to the XXXIX Rencontres de Moriond (2004), 4 pages, 2 figure

    Review of methods for preparatin of zinc and cadmium sulfide, selenide and telluride single cyrstals

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    The growth method of (Zn,Cd)S, (Zn,Cd)Se, (Zn,Cd)Te single crystals is reviewed. It is suggested that the method of sublimation-condensation is the most suitable to the conditions and facilities available, and should be employed in the Department of Physics of Bislystok Polytechnic

    Search for exotic long-lived particles at CLIC

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    A study of the sensitivity of the CLIC ILD detector model for massive long-lived particles produced in the decay of the Higgs boson is presented, using a data sample of e+e−e^+e^- collisions at centre-of-mass energy of 350 GeV and 3 TeV, corresponding to an integrated luminosity of 1 ab-1 and 3 ab-1, respectively. The sensitivity range covers long-lived particle lifetimes from 1 to 300 ps, masses between 25 and 50 GeV, and a parent Higgs mass of 126 GeV. Sensitivities to the production cross-section as a function of the long-lived particle mass and lifetime are determined.Comment: 11 pages, 7 figures. Revision for journal publicatio

    VELO-TT track reconstruction

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    The paper describes the track reconstruction in the system of VELO and TT detectors. Two separate algorithms for off-line and on-line approaches were merged. The single algorithm consists of the common code for pattern recognition and two parts specific to off-line and on-line functionalities. The note presents the performance in terms of track reconstruction efficiency and ghost rate

    Primary vertex reconstruction

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    This report reviews the improved method of primary vertex off-line reconstruction. The new method for primary vertex seed finding as well as modified procedure for vertex fit have been briefly described. Results of the primary vertex reconstruction performance are presented and compared to the previous version of the package. Improvement in the primary vertex reconstruction efficiencies is observed. Small but statistically significant bias, coming mostly from the long-living tracks as well as from a bias of the Velo measurements present in the DC06 simulation, affects the determination of the primary vertex position along the beam direction

    Probing the reaction pathway in (La_(0.8)Sr_(0.2))_(0.95)MnO_(3+ÎŽ) using libraries of thin film microelectrodes

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    Libraries of (La_(0.8)Sr_(0.2))_(0.95)MnO_(3+ÎŽ) (LSM) thin film microelectrodes with systematically varied thickness or growth temperature were prepared by pulsed laser deposition, and a novel robotic instrument was used to characterize these libraries in automated fashion by impedance spectroscopy. The measured impedance spectra are found to be described well by an electrochemical model based on a generalized transmission model for a mixed conducting oxide, and all trends are consistent with a reaction pathway involving oxygen reduction over the LSM surface followed by diffusion through the film and into the electrolyte substrate. The surface activity is found to be correlated with the number of exposed grain boundary sites, which decreases with either increasing film thickness (at constant growth temperature) or increasing film growth temperature (at constant thickness). These findings suggest that exposed grain boundaries in LSM films are more active than exposed grains towards the rate-limiting surface process, and that oxygen ion diffusion through polycrystalline LSM films is faster than many prior studies have concluded

    Consequences of the pathogenic T9176C mutation of human mitochondrial DNA on yeast mitochondrial ATP synthase

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    Several human neurological disorders have been associated with various mutations affecting mitochondrial enzymes involved in cellular ATP production. One of these mutations, T9176C in the mitochondrial DNA (mtDNA), changes a highly conserved leucine residue into proline at position 217 of the mitochondrially encoded Atp6p (or a) subunit of the F1FO-ATP synthase. The consequences of this mutation on the mitochondrial ATP synthase are still poorly defined. To gain insight into the primary pathogenic mechanisms induced by T9176C, we have investigated the consequences of this mutation on the ATP synthase of yeast where Atp6p is also encoded by the mtDNA. In vitro, yeast atp6-T9176C mitochondria showed a 30% decrease in the rate of ATP synthesis. When forcing the F1FO complex to work in the reverse mode, i.e. F1-catalyzed hydrolysis of ATP coupled to proton transport out of the mitochondrial matrix, the mutant showed a normal proton-pumping activity and this activity was fully sensitive to oligomycin, an inhibitor of the ATP synthase proton channel. However, under conditions of maximal ATP hydrolytic activity, using non-osmotically protected mitochondria, the mutant ATPase activity was less efficiently inhibited by oligomycin (60% inhibition versus 85% for the wild type control). Blue Native Polyacrylamide Gel Electrophoresis analyses revealed that atp6-T9176C yeast accumulated rather good levels of fully assembled ATP synthase complexes. However, a number of sub-complexes (F1, Atp9p-ring, unassembled alpha-F1 subunits) could be detected as well, presumably because of a decreased stability of Atp6p within the ATP synthase. Although the oxidative phosphorylation capacity was reduced in atp6-T9176C yeast, the number of ATP molecules synthesized per electron transferred to oxygen was similar compared with wild type yeast. It can therefore be inferred that the coupling efficiency within the ATP synthase was mostly unaffected and that the T9176C mutation did not increase the proton permeability of the mitochondrial inner membrane
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