Self-energy of image states on copper surfaces

We report extensive calculations of the imaginary part of the electron self-energy in the vicinity of the (100) and (111) surfaces of Cu. The quasiparticle self-energy is computed by going beyond a free-electron description of the metal surface, either within the GW approximation of many-body theory or with inclusion, within the GW$\Gamma$ approximation, of short-range exchange-correlation effects. Calculations of the decay rate of the first three image states on Cu(100) and the first image state on Cu(111) are also reported, and the impact of both band structure and many-body effects on the electron relaxation process is discussed.Comment: 8 pages, 5 figures, to appear in Phys. Rev.

Gene by Disease Interaction on Orbitofrontal Gray Matter in Cocaine Addiction

Chronic cocaine use has been associated with structural deficits in brain regions having dopamine receptive neurons. However, the concomitant use of other drugs and common genetic variability in monoamine regulation present additional structural variability. We therefore examined variations in gray matter volume (GMV) as a function of lifetime drug use and the monoamine oxidase A (MAOA) genotype in cocaine use disorders (CUD) and healthy controls

Implicit Reasons for Disclosure of the Use of Complementary Health Approaches (CHA): a Consumer Commitment Perspective

Background: Disclosure of the use of complementary health approaches (CHA) is an important yet understudied health behaviour with important implications for patient care. Yet research into disclosure of CHA has been atheoretical and neglected the role of health beliefs. Purpose: Using a consumer commitment model of CHA use as a guiding conceptual framework, the current study tests the hypotheses that perceived positive CHA outcomes (utilitarian values) and positive CHA beliefs (symbolic values) are associated with disclosure of CHA to conventional-care providers in a nationally representative US sample. Methods: From a sample of 33,594 with CHA use information from the 2012 National Health Interview Survey (NHIS), a subsample of 7,348 who used CHA within the past 12 months was analysed. The 2012 NHIS is a cross-sectional survey of the non-institutionalized US adult population, which includes the most recent nationally representative CHA use data. Results: The 63.2 % who disclosed CHA use were older, less educated, and had visited a health-care provider in the past year. Weighted logistic regression analyses controlling for demographic variables revealed that those who disclosed were more likely to report experiencing positive psychological (improved coping and well-being) and physical outcomes (better sleep, improved health) from CHA, and hold positive CHA-related beliefs. Conclusions: CHA users who perceive physical and psychological benefits from CHA use, and who hold positive attitudes towards CHA are more likely to disclose their CHA use. Findings support the relevance of a consumer commitment perspective for understanding CHA disclosure, and suggest CHA disclosure as an important proactive health behaviour that warrants further attention

Reasons for continuing use of Complementary and Alternative Medicine (CAM) in students: a consumer commitment model

Background: Research on continued CAM use has been largely atheoretical and has not considered the broader range of psychological and behavioral factors that may be involved. The purpose of this study was to test a new conceptual model of commitment to CAM use that implicates utilitarian (trust in CAM) and symbolic (perceived fit with CAM) in psychological and behavioral dimensions of CAM commitment. Methods: A student sample of CAM consumers, (N= 159) completed a survey about their CAM use, CAM-related values, intentions for future CAM use, CAM word-of-mouth behavior, and perceptions of being an ongoing CAM consumer. Results: Analysis revealed that the utilitarian, symbolic, and CAM commitment variables were significantly related, with r’s ranging from .54 to .73. A series hierarchical regression analyses controlling for relevant demographic variables found that the utilitarian and symbolic values uniquely accounted for significant and substantial proportion of the variance in each of the three CAM commitment indicators (R2 from .37 to .57). Conclusions: The findings provide preliminary support for the new model that posits that CAM commitment is a multi-dimensional psychological state with behavioral indicators. Further research with large-scale samples and longitudinal designs is warranted to understand the potential value of the new model

Association between Dopamine D4 Receptor Polymorphism and Age Related Changes in Brain Glucose Metabolism

Aging is associated with reductions in brain glucose metabolism in some cortical and subcortical regions, but the rate of decrease varies significantly between individuals, likely reflecting genetic and environmental factors and their interactions. Here we test the hypothesis that the variant of the dopamine receptor D4 (DRD4) gene (VNTR in exon 3), which has been associated with novelty seeking and sensitivity to environmental stimuli (negative and positive) including the beneficial effects of physical activity on longevity, influence the effects of aging on the human brain. We used positron emission tomography (PET) and [18F]fluoro-D-glucose (18FDG) to measure brain glucose metabolism (marker of brain function) under baseline conditions (no stimulation) in 82 healthy individuals (age range 22–55 years). We determined their DRD4 genotype and found an interaction with age: individuals who did not carry the 7-repeat allele (7R−, n = 53) had a significant (p<0.0001) negative association between age and relative glucose metabolism (normalized to whole brain glucose metabolism) in frontal (r = −0.52), temporal (r = −0.51) and striatal regions (r = −0.47, p<0.001); such that older individuals had lower metabolism than younger ones. In contrast, for carriers of the 7R allele (7R+ n = 29), these correlations with age were not significant and they only showed a positive association with cerebellar glucose metabolism (r = +0.55; p = 0.002). Regression slopes of regional brain glucose metabolism with age differed significantly between the 7R+ and 7R− groups in cerebellum, inferior temporal cortex and striatum. These results provide evidence that the DRD4 genotype might modulate the associations between regional brain glucose metabolism and age and that the carriers of the 7R allele appear to be less sensitive to the effects of age on brain glucose metabolism

Association between Dopamine D4 Receptor Polymorphism and Age Related Changes in Brain Glucose Metabolism

<div><p>Aging is associated with reductions in brain glucose metabolism in some cortical and subcortical regions, but the rate of decrease varies significantly between individuals, likely reflecting genetic and environmental factors and their interactions. Here we test the hypothesis that the variant of the dopamine receptor D4 (<i>DRD4</i>) gene (VNTR in exon 3), which has been associated with novelty seeking and sensitivity to environmental stimuli (negative and positive) including the beneficial effects of physical activity on longevity, influence the effects of aging on the human brain. We used positron emission tomography (PET) and [¹⁸F]fluoro-D-glucose (¹⁸FDG) to measure brain glucose metabolism (marker of brain function) under baseline conditions (no stimulation) in 82 healthy individuals (age range 22–55 years). We determined their DRD4 genotype and found an interaction with age: individuals who did not carry the 7-repeat allele (<b>7R−</b>, n = 53) had a significant (p<0.0001) negative association between age and relative glucose metabolism (normalized to whole brain glucose metabolism) in frontal (r = <b>−</b>0.52), temporal (r = <b>−</b>0.51) and striatal regions (r = <b>−</b>0.47, p<0.001); such that older individuals had lower metabolism than younger ones. In contrast, for carriers of the 7R allele (<b>7R+</b> n = 29), these correlations with age were not significant and they only showed a positive association with cerebellar glucose metabolism (r = +0.55; p = 0.002). Regression slopes of regional brain glucose metabolism with age differed significantly between the <b>7R+</b> and <b>7R−</b> groups in cerebellum, inferior temporal cortex and striatum. These results provide evidence that the DRD4 genotype might modulate the associations between regional brain glucose metabolism and age and that the carriers of the 7R allele appear to be less sensitive to the effects of age on brain glucose metabolism.</p></div