Is charm the key to understanding diffraction in DIS ?

This talk concerns the production of open charm in diffractive deep inelastic scattering. This has been calculated recently in the context of the semi-classical approach to diffraction. A comparison is made to approaches in which the diffractive exchange is modelled by the exchange of two gluons in the $t$-channel. Two phenomenological test of the underlying partonic process are discussed.Comment: 6 pages, latex, 5 figures. Talk given at the diffractive working group of DIS '97, Chicago Il. The required AIP style files are provide

Psychological Predictors of Mortality Awareness: Time Perspective, Contentment With Age and Paternal Antipathy and Neglect

Much research has focused upon the association between mortality awareness and mental ill-health. In this study we attempt to explore positive as well as negative psychological concomitants of mortality awareness. 170 participants were recruited in an online questionnaire study, measuring seven independent variables - marginalisation, childhood adversity, rebelliousness, time perspective, attitudes toward age and stage of life, health attitudes and demographics - and five dependent variables, specifically mortality legacy, mortality fearfulness, mortality acceptance, mortality disempowerment and mortality disengagement. Several significant bivariate associations were found. Follow-up regression analysis observed combined effects of variables accounting for 28% of variance in mortality legacy, 27% for mortality fearfulness, 13% for mortality acceptance, 42% for mortality disempowerment and 25% for mortality disengagement. Time perspective, contentment with age, and paternal antipathy and neglect were the most notable independent predictors. It was concluded that attitudes towards health, stage of life and childhood experiences significantly predict mortality awareness

Next-to-leading order evolution of generalized parton distributions for HERA and HERMES

The QCD evolution of both unpolarized and polarized generalized parton distributions (GPDs) to next-to-leading order (NLO) accuracy is presented, in both the DGLAP and ERBL regions, for two appropriately symmetrized input distributions based on conventional parton density functions. To illustrate the relative size of the NLO corrections a comparison is made with leading order evolution of the same distributions. For the first time, NLO results are given for both small and large values of the skewedness parameter, $\zeta = x_{bj}$, i.e. for all of the kinematic range relevant to HERA and HERMES.Comment: 11 pages, 8 figures, latex, uses revtex style files, published version + corrections of erratum edited in. references update

Further analysis of the BFKL equation with momentum cutoffs

In this paper we investigate the effect of introducing transverse momentum cutoffs on the BFKL equation. We present solutions in moment space for various models of the BFKL kernel for different combinations of these cutoffs. We improve on previous calculations by using the full BFKL kernel (rather than simplified analytic approximations). The significance of the next-to-leading or ``higher twist'' terms in the kernel are assessed. We find that, while these terms are negligible in the absence of cutoffs, introducing an infra-red cutoff markedly enhances their significance.Comment: 27 pages, latex, 6 figure

Diffractive Photoproduction of Υ\Upsilon at HERA

Predictions for the diffractive photoproduction of the $\Upsilon$-family at HERA energies, within the framework of the analysis by Frankfurt, Koepf and Strikman, are presented. Two novel effects lead to a significant enhancement of the original calculation: the non-diagonal (or skewed) kinematics, calculated to leading-log($Q^2$) accuracy, and the large magnitude of the real part of the amplitude. The resultant cross sections are found to agree fairly well with recent preliminary data from ZEUS and H1. A strong correlation between the mass of the diffractively produced state and the energy dependence of the cross section is found. In particular, a considerably stronger rise in energy is predicted than that found in $J/\psi$-production.Comment: 13 pages, latex2e, 5 figures, 5 tables. Revised version corrects a bug in the original code, the effect is to reduce the normalization by about 40%. Figures 3-5 updated. Minor modifications and clarifications included in the text in response to referees report. Qualitative conclusions remain unchange

Learning physics in context: a study of student learning about electricity and magnetism

This paper re-centres the discussion of student learning in physics to focus on context. In order to do so, a theoretically-motivated understanding of context is developed. Given a well-defined notion of context, data from a novel university class in electricity and magnetism are analyzed to demonstrate the central and inextricable role of context in student learning. This work sits within a broader effort to create and analyze environments which support student learning in the sciencesComment: 36 pages, 4 Figure