Quasi-particle Lifetimes in a d_{x^2-y^2} Superconductor

We consider the lifetime of quasi-particles in a d-wave superconductor due to scattering from antiferromagnetic spin-fluctuations, and explicitly separate the contribution from Umklapp processes which determines the electrical conductivity. Results for the temperature dependence of the total scattering rate and the Umklapp scattering rate are compared with relaxation rates obtained from thermal and microwave conductivity measurements, respectively.Comment: 14 pages, 4 figure

Relationships of psychosocial factors to dietary intakes of preadolescent girls from diverse backgrounds

Family and personal factors that might be related to the development of food selection and eating patterns have not been well studied in children. The aim of this study was to examine whether such psychosocial factors differ in girls from four culturally diverse Girl Scout troops and how these factors are associated with dietary intakes. The social measures and dietary assessments were all obtained at baseline on subjects who were participating in a small nutrition education programme. The programme enrolled girls and one parent for each girl from four Girl Scout troops in Detroit, Michigan. The social factors assessed included girls’ emotionality and use of food to regulate emotions, their general attitudes about health, eating and body image, and self-perceptions of their competence. Dietary intakes also were assessed in both the girls and their parents. There were large differences between troops in ethnicity and parent education level, and there were differences in dietary intakes as well. The psychosocial factors assessed in this study, however, did not differ significantly by troop. When the psychosocial factors were examined for their relationships to dietary factors, there was an indication that families which reported higher self-competence and academic competence in their daughters also had healthier eating patterns in their daughters. This was a small study, but the data suggest that simple comparisons between ethnic groups may not adequately capture the complexity of family and psychosocial factors contributing to good dietary practices.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73597/1/j.1740-8709.2006.00051.x.pd

NUMBER: standardized reference intervals in the Netherlands using a 'big data' approach

Clinical epidemiolog

Representationalism versus anti-representationalism: a debate for the sake of appearance

Item does not contain fulltextIn recent years the cognitive science community has witnessed the rise of a new, dynamical approach to cognition. This approach entails a framework in which cognition and behavior are taken to result from complex dynamical interactions between brain, body, and environment. The advent of the dynamical approach is grounded in a dissatisfaction with the classical computational view of cognition. A particularly strong claim has been that cognitive systems do not rely on internal representations and computations. Focusing on this claim, we take as a starting point a question recently raised by Cliff and Noble: "... if evolution did produce a design that used internal representations, how would we recognize it?" (Knowledge-based vision and simple visual machines, Philosophical Transactions of the Royal Society: Biological Sciences, 352, 1165-1175, 1997). We will argue that cognitive science lacks a proper operationalization of the notion of representation, and therefore is unable to ftuitfully discuss whether a particular system has representations or not. A basic method to detect representations in a physical system, grounded in isomorphism, turns out to be quite unconstrained. We will look at a practical example of this problem by examining the debate on whether or not van Gelder's (What might cognition be, if not computation? Journal of Philosophy, 92, 345-381, 1995) controversial example of the Watt Governor is representational. We will conclude that cognitive science, as of yet, has no empirically applicable means to answer Cliff and Noble's question unequivocally. This makes the recent representationalism vs. anti-representationalism debate a debate for the sake of appearance