76 research outputs found
Inelastic J/psi Photoproduction
Inelastic photoproduction of particles at high energies is one of
the processes to determine the gluon distribution in the nucleon. We have
calculated the QCD radiative corrections to the color-singlet model of this
reaction. They are large at moderate photon energies, but decrease with
increasing energies. The cross section and the energy spectrum are
compared with the available fixed-target photoproduction data and predictions
are given for the HERA energy range.Comment: 14 pages, latex, 7 uuencoded figure
Vitamin A, carotenoid and vitamin E plasma concentrations in children from Laos in relation to sex and growth failure
BACKGROUND: Deficiencies of vitamin A and its precursors, the carotenoids are common problems in developing countries. Plasma levels of these components are used as biomarkers of their availability. The study was conducted to evaluate whether blood plasma obtained from capillaries can be compared with plasma obtained from venous blood with regard to its levels of retinol, carotenoids and α-tocopherol and secondly to apply this technique to evaluate the levels of these components in children in a region with possible deficiencies. METHODS: The survey was conducted in a region of Laos in 81 children (age 35 to 59 months). Dietary intake was assessed by a questionnaire. Retinol, carotenoids and α-tocopherol were determined by HPLC. Blood plasma was obtained either from capillary blood collected into microcapillaries and for reasons of methodological comparison in 14 adults from venous blood. RESULTS: The comparison between capillary and venous blood revealed that all components except zeaxanthin were 9 – 23 % higher in plasma obtained from capillary blood. Results in Laotian children showed that all investigated components except retinol were significantly lower (P < 0.01) compared to European children of slightly older age. Contrary to children in Europe, most components were significantly lower in boys compared to girls. In children from Laos, lutein was the dominant carotenoid, while in children in Europe, β-carotene was dominant. Within the Laotian children only a few differences were observed between stunted and non-stunted children and between children from lowland areas and high land areas. CONCLUSIONS: Results show that in consideration of slightly lower levels than in venous blood, capillary blood can be used to evaluate retinol, carotenoids and α-tocopherol as biomarkers of intake or status and to evaluate the possible effect of diet on absolute and relative carotenoid composition in children from Europe and Laos. Observed sex related differences might not be related to diet and would need further investigation
Changes in LDL Fatty Acid Composition as a Response to Olive Oil Treatment Are Inversely Related to Lipid Oxidative Damage: The EUROLIVE Study
Objective: The aim of our study was to assess the changes in the fatty acid composition of low density lipoproteins (LDL) after sustained consumption of olive oil at real-life doses (25 mL/day) and their relationship with lipid oxidative damage. Methods: A multi-center randomized, cross-over, clinical trial with 3 similar types of olive oils, but with differences in the phenolic content, was conducted on 200 healthy European subjects. Intervention periods were of 3 weeks separated by 2-week washout periods. The LDL fatty acid content was measured in samples drawn at baseline and after the last intervention period. Results: After olive oil ingestion oleic acid concentration in LDL increased (1.9%; p Ͻ 0.001) and those of linoleic (1.1%; p Ͻ 0.002) and arachidonic acid (0.5%; p Ͻ 0.001) decreased. Monounsaturated/polyunsaturated fatty acid and oleic/linoleic acid ratios in LDL increased after olive oil consumption. An inverse relationship between the oleic/linoleic acid ratio and biomarkers of oxidative stress was observed. One unit increase in the oleic/linoleic acid ratio was associated with a decrease of 4.2 g/L in plasma isoprostanes. Conclusion: Consumption of olive oil at real-life doses improved the fatty acid profile in LDL, the changes being associated with a reduction of the oxidative damage to lipids
Contribution of Individual and Environmental Factors to Physical Activity Level among Spanish Adults
BACKGROUND: Lack of physical activity (PA) is a major risk for chronic disease and obesity. The main aims of the present study were to identify individual and environmental factors independently associated with PA and examine the relative contribution of these factors to PA level in Spanish adults. METHODOLOGY/PRINCIPAL FINDINGS: A population-based cross-sectional sample of 3,000 adults (18-75 years old) from Gran Canaria (Spain) was selected using a multistage stratified random sampling method. The participants were interviewed at home using a validated questionnaire to assess PA as well as individual and environmental factors. The data were analyzed using bivariate and multivariate logistic regression. One demographic variable (education), two cognitive (self-efficacy and perceived barriers), and one social environmental (organized format) were independently associated with PA in both genders. Odds ratios ranged between 1.76-2.07 in men and 1.35-2.50 in women (both p<0.05). Individual and environmental factors explained about one-third of the variance in PA level. CONCLUSIONS/SIGNIFICANCE: Self-efficacy and perceived barriers were the most significant factors to meet an adequate level of PA. The risk of insufficient PA was twofold greater in men with primary or lesser studies and who are employed. In women, living in rural environments increased the risk of insufficient PA. The promotion of organized PA may be an efficient way to increase the level of PA in the general population. Improvement in the access to sport facilities and places for PA is a prerequisite that may be insufficient and should be combined with strategies to improve self-efficacy and overcome perceived barriers in adulthood
'Get healthy, stay healthy': Protocol for evaluation of a lifestyle intervention delivered by text-message following the Get Healthy Information and Coaching Service®
Background: Behavioural lifestyle interventions can be effective at promoting initial weight loss and supporting physical activity and dietary behaviour change, however maintaining improvements in these outcomes is often more difficult to achieve. Extending intervention contact to reinforce learnt behavioural skills has been shown to improve maintenance of behaviour change and weight loss. This trial aims to evaluate the feasibility, acceptability and efficacy of a text message-delivered extended contact intervention to enhance or maintain change in physical activity, dietary behaviour and weight loss among participants who have completed a six month Government-funded, population-based telephone coaching lifestyle program: the Get Healthy Information and Coaching Service (GHS). Methods/Design. GHS completers will be randomised to the 6-month extended contact intervention (Get Healthy, Stay Healthy, GHSH) or a no contact control group (standard practice following GHS completion). GHSH participants determine the timing and frequency of the text messages (3-13 per fortnight) and content is tailored to their behavioural and weight goals and support preferences. Two telephone tailoring calls are made (baseline, 12-weeks) to facilitate message tailoring. Primary outcomes, anthropometric (body weight and waist circumference via self-report) and behavioural (moderate-vigorous physical activity via self-report and accelerometer, fruit and vegetable intake via self-report), will be assessed at baseline (at GHS completion), 6-months (end of extended contact intervention) and 12-months (6-months post intervention contact). Secondary aims include evaluation of: the feasibility of program delivery; the acceptability for participants; theoretically-guided, potential mediators and moderators of behaviour change; dose-responsiveness; and, costs of program delivery. Discussion. Findings from this trial will inform the delivery of the GHS in relation to the maintenance of behaviour change and weight loss, and will contribute to the broader science of text message lifestyle interventions delivered in population health settings. Trial registration. ACTRN12613000949785
Photoproduction
Inelastic photoproduction of J=/ particles at high energies is one of the processes to determine the gluon distribution in the nucleon. We have calculated the QCD radiative corrections to the color-singlet model of this reaction. They are large at moderate photon energies, but decrease with increasing energies. The cross section and the J=/ energy spectrum are compared with the available fixed-target photoproduction data and predictions are given for the HERA energy range. Supported in part by Deutsche Forschungsgemeinschaft DFG y Present address: Deutsches Elektronen-Synchrotron DESY, D-22603 Hamburg FRG; E-mail: [email protected] The measurement of the gluon distribution in the nucleon is one of the important goals of lepton-nucleon scattering experiments. The classical methods exploit the evolution of the nucleon structure functions with the momentum transfer, and the size of the longitudinal structure function. With rising energies, however, jet physics and the production..
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