21 research outputs found
Can Simply Answering Research Questions Change Behaviour? Systematic Review and Meta Analyses of Brief Alcohol Intervention Trials
BACKGROUND: Participant reports of their own behaviour are critical for the provision and evaluation of behavioural interventions. Recent developments in brief alcohol intervention trials provide an opportunity to evaluate longstanding concerns that answering questions on behaviour as part of research assessments may inadvertently influence it and produce bias. The study objective was to evaluate the size and nature of effects observed in randomized manipulations of the effects of answering questions on drinking behaviour in brief intervention trials. METHODOLOGY/PRINCIPAL FINDINGS: Multiple methods were used to identify primary studies. Between-group differences in total weekly alcohol consumption, quantity per drinking day and AUDIT scores were evaluated in random effects meta-analyses. Ten trials were included in this review, of which two did not provide findings for quantitative study, in which three outcomes were evaluated. Between-group differences were of the magnitude of 13.7 (-0.17 to 27.6) grams of alcohol per week (approximately 1.5 U.K. units or 1 standard U.S. drink) and 1 point (0.1 to 1.9) in AUDIT score. There was no difference in quantity per drinking day. CONCLUSIONS/SIGNIFICANCE: Answering questions on drinking in brief intervention trials appears to alter subsequent self-reported behaviour. This potentially generates bias by exposing non-intervention control groups to an integral component of the intervention. The effects of brief alcohol interventions may thus have been consistently under-estimated. These findings are relevant to evaluations of any interventions to alter behaviours which involve participant self-report
Stereoselective additions to [60]fullerene
1,3-Dipolar cycloaddition of chiral azomethine ylides to C-60 affords
mixtures of diastereoisomeric fulleropyrrolidines, which can be
separated by flash chromatography; the structure of the adducts is
supported by unambiguous NOE enhancements, and CD curves of the adducts
can be of help in the assignment of the absolute configuration
EFFECTS OF ATMOSPHERIC EMISSION ON GROUND-BASED MICROWAVE BACKGROUND MEASUREMENTS
We present an analysis of multifrequency measurements of atmospheric emission in the Rayleigh-jeans portion of the cosmic microwave background spectrum (1-90 GHz) taken since 1986 from White Mountain, CA, and from the South Pole. Correlations of simultaneous data at 10 and 90 GHz and accurate low-frequency measurements show good agreement with model predictions for both sites. Our data from the South Pole 1989 campaign combined with real-time measurements of the local atmospheric profiles provide accurate verification of the expected independent contributions of H2O and O-2 emission. We show that variations on the order of 10% of the oxygen emission (both resonant and nonresonant components) are present on timescales of hours to days, mainly due to the evolution of the atmospheric pressure profile. Oxygen emission fluctuations appear larger than previously expected and may have significant consequences for ground-based cosmic microwave background experiments
Drying kinetics of fermented grape pomace: Determination of moisture effective diffusivity
ABSTRACT The aim of this study was to obtain the equilibrium moisture content of grape (variety ‘Tannat’) pomace through desorption isotherms, to evaluate the drying kinetics, determine the coefficient of effective diffusivity and physico-chemically characterize the grape pomace and the product obtained after drying. The desorption isotherms were determined at 50, 60 and 70 ºC and the experimental data were fitted using the GAB model (Gugghenheim, Anderson and de Boer). Drying was evaluated using a 22 factorial experimental design with three center points and effective diffusivity was obtained through the diffusion model of Fick’s second law. The grape pomace was characterized regarding the contents of moisture, protein, carbohydrates, lipids, ash and dietary crude fiber. The obtained isotherms showed sigmoid shape and the experimental data fitted well to the GAB model. The drying curves showed only a decreasing rate period. The effective diffusivity values were within the range for organic materials. Dry grape pomace showed high contents of protein and fiber and can be used in the development of new products, in order to increase the nutritional content and add value to this byproduct