3,760 research outputs found

    Review of the measurements of the strong coupling constant at LEP 2

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    Since 1995, LEP has steadily increased the center of mass energy of the colliding beams, from the M_Z resonance to 133, 161 and 172 GeV. New measurements of the strong coupling constant, alpha_s, at these energies have been performed by the LEP experiments, L3, ALEPH, OPAL and DELPHI. In this article, the new results are summarized, and combined with the previous LEP measurement of alpha_s(M_Z) in order to obtain an updated LEP average of alpha_s(M_Z) = 0.120 +- 0.005.Comment: 5-6 pages, 3 figures. Talk given at the DIS 97 conference, Chicago, April 1997.Replacement: update figure 1. Also available here http://hep.ph.liv.ac.uk/~martis

    An ALMA Early Science survey of molecular absorption lines toward PKS1830-211 -- Analysis of the absorption profiles

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    We present the first results of an ALMA spectral survey of strong absorption lines for common interstellar species in the z=0.89 molecular absorber toward the lensed blazar PKS1830-211. The dataset brings essential information on the structure and composition of the absorbing gas in the foreground galaxy. In particular, we find absorption over large velocity intervals (gtrsim 100 km/s) toward both lensed images of the blazar. This suggests either that the galaxy inclination is intermediate and that we sample velocity gradients or streaming motions in the disk plane, that the molecular gas has a large vertical distribution or extraplanar components, or that the absorber is not a simple spiral galaxy but might be a merger system. The number of detected species is now reaching a total of 42 different species plus 14 different rare isotopologues toward the SW image, and 14 species toward the NE line-of-sight. The abundances of CH, H2O, HCO+, HCN, and NH3 relative to H2 are found to be comparable to those in the Galactic diffuse medium. Of all the lines detected so far toward PKS1830-211, the ground-state line of ortho-water has the deepest absorption. We argue that ground-state lines of water have the best potential for detecting diffuse molecular gas in absorption at high redshift.Comment: Accepted for publication in A&

    Concepts and methods in studies measuring individual ethnobotanical knowledge

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    We review 34 quantitative studies that have measured individuallevel variations in ethnobotanical knowledge, analyzing how those studies have conceptualized and operationalized ethnobotanical knowledge. We found that this type of research is recent but growing, and is concentrated in indigenous peoples of developing countries. We also found that studies differ on how they conceptualize and measure individual ethnobotanical knowledge. As it is the case in other interdisciplinary research, the lack of conceptual consistency and comparable data limit the inferences that can be drawn from empirical analyses of ethnobotanical knowledge. Future research should 1) validate the consistency of measures of individual ethnobotanical knowledge; 2) analyze the reliability of data generated by the different methods developed so far; and 3) address the relationship between the various dimensions of ethnobotanical knowledge. Studies of individual ethnobotanical knowledge have the potential to contribute to a systematic understanding of humanity’s most widespread and ancient form of knowledge

    The serenity of the meditating mind: A cross-cultural psychometric study on a two-factor higher order structure of mindfulness, its effects, and mechanisms related to mental health among experienced meditators.

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    Objective To investigate the psychometric and structural properties of the Five Facets Mindfulness Questionnaire (FFMQ) among meditators, to develop a short form, and to examine associations of mindfulness with mental health and the mechanisms of mindfulness. Methods Two independent samples were used, a German (n‚Ää=‚Ää891) and a Spanish (n‚Ää=‚Ää393) meditator sample, practicing various meditation styles. Structural and psychometric properties of the FFMQ were investigated with multigroup confirmatory factor analysis and exploratory structural equation modeling. Associations with mental health and mechanisms of mindfulness were examined with path analysis. Results The derived short form broadly matched a previous item selection in samples of non-meditators. Self-regulated Attention and Orientation to Experience governed the facets of mindfulness on a higher-order level. Higher-order factors of mindfulness and meditation experience were negatively associated with symptoms of depression and anxiety, and perceived stress. Decentering and nonattachment were the most salient mechanisms of mindfulness. Aspects of emotion regulation, bodily awareness, and nonattachment explained the effects of mindfulness on depression and anxiety. Conclusions A two-component conceptualization for the FFMQ, and for the study of mindfulness as a psychological construct, is recommended for future research. Mechanisms of mindfulness need to be examined in intervention studies

    Dietary total antioxidant capacity is associated with leukocyte telomere length in a children and adolescent population

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    Background & Aims: Oxidative stress and inflammation seem to be potential underlying mechanisms for telomere attrition. A lack of specific antioxidants is believed to increase free radical damage and a greater risk for telomere shortening. Our aim was to evaluate the relationship between diet and leukocyte telomere length in a cross-sectional study of children and adolescents. We hypothesized that dietary total antioxidant capacity would be positively associated with telomere length. Methods: Telomere length was measured by quantitative real-time polymerase chain reaction in 287 participants (55% males, 6‚Äď18 years), who were randomly selected from the GENOI study. Results: A positive correlation between dietary total antioxidant capacity and telomere length (r=0.157, p=0.007) was found after adjustment for age and energy intake. However, higher white bread consumption was associated with shorter telomeres (ő≤=-0.204, p=0.002) in fully-adjusted models. Interestingly, those individuals who had simultaneously higher dietary total antioxidant capacity and lower white bread consumption significantly presented the longest telomeres. Moreover, the multivariable-adjusted odds ratio for very short telomeres was 0.30 for dietary total antioxidant capacity (p=0.023) and 1.37 for white bread (p=0.025). Conclusion: It was concluded that longer telomeres were associated with higher dietary total antioxidant capacity and lower white bread consumption in S2panish children and adolescents. These findings might open a new line of investigation about the potential role of an antioxidant diet in maintaining telomere length
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