24 research outputs found

    The Deuteron Spin-dependent Structure Function g1d and its First Moment

    Get PDF
    We present a measurement of the deuteron spin-dependent structure function g1d based on the data collected by the COMPASS experiment at CERN during the years 2002-2004. The data provide an accurate evaluation for Gamma_1^d, the first moment of g1d(x), and for the matrix element of the singlet axial current, a0. The results of QCD fits in the next to leading order (NLO) on all g1 deep inelastic scattering data are also presented. They provide two solutions with the gluon spin distribution function Delta G positive or negative, which describe the data equally well. In both cases, at Q^2 = 3 (GeV/c)^2 the first moment of Delta G is found to be of the order of 0.2 - 0.3 in absolute value.Comment: fits redone using MRST2004 instead of MRSV1998 for G(x), correlation matrix adde

    A new measurement of the Collins and Sivers asymmetries on a transversely polarised deuteron target

    Get PDF
    New high precision measurements of the Collins and Sivers asymmetries of charged hadrons produced in deep-inelastic scattering of muons on a transversely polarised 6LiD target are presented. The data were taken in 2003 and 2004 with the COMPASS spectrometer using the muon beam of the CERN SPS at 160 GeV/c. Both the Collins and Sivers asymmetries turn out to be compatible with zero, within the present statistical errors, which are more than a factor of 2 smaller than those of the published COMPASS results from the 2002 data. The final results from the 2002, 2003 and 2004 runs are compared with naive expectations and with existing model calculations.Comment: 40 pages, 28 figure

    The COMPASS Experiment at CERN

    Get PDF
    The COMPASS experiment makes use of the CERN SPS high-intensitymuon and hadron beams for the investigation of the nucleon spin structure and the spectroscopy of hadrons. One or more outgoing particles are detected in coincidence with the incoming muon or hadron. A large polarized target inside a superconducting solenoid is used for the measurements with the muon beam. Outgoing particles are detected by a two-stage, large angle and large momentum range spectrometer. The setup is built using several types of tracking detectors, according to the expected incident rate, required space resolution and the solid angle to be covered. Particle identification is achieved using a RICH counter and both hadron and electromagnetic calorimeters. The setup has been successfully operated from 2002 onwards using a muon beam. Data with a hadron beam were also collected in 2004. This article describes the main features and performances of the spectrometer in 2004; a short summary of the 2006 upgrade is also given.Comment: 84 papes, 74 figure

    Biological, epidemiological, sanitary-hygienic, medical and behavioral occupational health risk factors for stock-breeders, veterinaries and workers employed at meat-processing enterprises, contacting brucellar animals and infected meat

    No full text
    We have studied sanitary-hygienic characteristics of working conditions, charts with results of sanitary-epidemiologic examination performed in a zoogenous nidus, outpatient clinic cards and questionnaires filled in by 202 patients living in Omsk region and suffering from occupational brucellosis. The disease usually prevails among stock-breeders, veterinaries and workers employed at meat-processing enterprises. Our goal was to detect risks of occupational, production-induced and general pathology evolvement. Working conditions which all the examined people had to work in corresponded to hazardous (3.3) or even dangerous (4) category as per occurrence of contacts with infectious agents and parasites (biological risk). Apart from biological factor, a number of workers were under complex exposure to ammonia concentrations (higher than MPC), noise higher than MPL, vibration, cooling microclimate, uncomfortable lighting environment, labor process hardness and intensity. There were several factors causing epidemiologic risks as well. Disinfectants were absent or their quantity was not sufficient; industrial and amenity rooms were not well-organized; there was no central hot water supply or shower rooms, separate rooms for meals, specialized implements for removing abortus and stillborn fetuses and afterbirths, correctly organized burial grounds, or first aid kits. Hygienic health risks were caused by insufficient cleaning agents supply, absence of centralized protecting clothing laundering, and insufficient provision with personal protection means. Occupational health risks resulted from absence of preliminary medical examinations in standard recruitment procedures, irregularity and low quality of periodical medical examinations. Our qualitative assessment of behavioral health risks revealed that a lot of workers tended to have irresponsible medical and hygienic behavior, there were disorders in their work and rest regime (shift work with shifts rotation), nutrition, sleeping and waking. We also found out that the examined workers didn't pursue self-preserving lifestyle as they drank alcohol, smoked, underestimated the importance of being vaccinated against brucellosis and of having medical examinations, and didn't apply for medical aid in due time. We detected the third type of risk-genous behavior, "high risk-genous level, passive" in 28.22 % of our respondent

    The role of beneficial bacteria wall elasticity in regulating innate immune response

    Get PDF
    Background: Probiotics have great potential to contribute to development of healthy dietary regimes, preventive care, and an integrated approach to immunity-related disease management. The bacterial wall is a dynamic entity, depending on many components and playing an essential role in modulating immune response. The impact of cell wall elasticity on the beneficial effects of probiotic strains has not been sufficiently studied. The aim was to investigate the effect of lactic acid bacteria (LAB) and bifidobacteria strains on phagocytic system cells (macrophages) as related to bacterial wall elasticity, estimated using atomic force microscopy (AFM). Methods: We conducted studies on Balb/c line mice 18\u201320 g in weight using lyophilized strains of LAB\u2014Lactobacillus acidophilus IMV B-7279, Lactobacillus casei IMV B-7280, Lactobacillus delbrueckii subsp. bulgaricus IMV B-7281, and bifidobacteria\u2014Bifidobacterium animalis VKL and Bifidobacterium animalis VKB. We cultivated the macrophages obtained from the peritoneal cavity of mice individually with the strains of LAB and bifidobacteria and evaluated their effect on macrophages, oxygen-dependent bactericidal activity, nitric oxide production, and immunoregulatory cytokines. We used AFM scanning to estimate bacterial cell wall elasticity. Results: All strains had a stimulating effect on the functional activity of macrophages and ability to produce NO/NO2 in vitro. Lactobacilli strains increased the production of IL-12 and IFN-\u3b3 in vitro. The AFM demonstrated different cell wall elasticity levels in various strains of LAB and bifidobacteria. The rigidity of the cell walls among lactobacilli was distributed as follows: Lactobacillus acidophilus IMV B-7279 > Lactobacillus casei IMV B-7280 > Lactobacillus delbrueckii subsp. bulgaricus IMV B-7281; among the strains of bifidobacteria: B. animalis VKB > B. animalis VKL. Probiotic strain survival in the macrophages depended on the bacterial cell wall elasticity and on the time of their joint cultivation. Conclusion: LAB and bifidobacteria strains stimulate immune-modulatory cytokines and active oxygen and nitrogen oxide compound production in macrophages. Strains with a more elastic cell wall according to AFM data demonstrated higher resistance to intracellular digestion in macrophages and higher level of their activation. AFM might be considered as a fast and accurate method to assess parameters of probiotic strain cell wall to predict their immune-modulatory properties
    corecore