The Resolved Asteroid Program - Size, shape, and pole of (52) Europa

With the adaptive optics (AO) system on the 10 m Keck-II telescope, we acquired a high quality set of 84 images at 14 epochs of asteroid (52) Europa on 2005 January 20. The epochs covered its rotation period and, by following its changing shape and orientation on the plane of sky, we obtained its triaxial ellipsoid dimensions and spin pole location. An independent determination from images at three epochs obtained in 2007 is in good agreement with these results. By combining these two data sets, along with a single epoch data set obtained in 2003, we have derived a global fit for (52) Europa of diameters (379x330x249) +/- (16x8x10) km, yielding a volume-equivalent spherical-diameter of 315 +/- 7 km, and a rotational pole within 7 deg of [RA; Dec] = [257,+12] in an Equatorial J2000 reference frame (ECJ2000: 255,+35). Using the average of all mass determinations available forEuropa, we derive a density of 1.5 +/- 0.4, typical of C-type asteroids. Comparing our images with the shape model of Michalowski et al. (A&A 416, 2004), derived from optical lightcurves, illustrates excellent agreement, although several edge features visible in the images are not rendered by the model. We therefore derived a complete 3-D description of Europa's shape using the KOALA algorithm by combining our imaging epochs with 4 stellar occultations and 49 lightcurves. We use this 3-D shape model to assess these departures from ellipsoidal shape. Flat facets (possible giant craters) appear to be less distinct on (52) Europa than on other C-types that have been imaged in detail. We show that fewer giant craters, or smaller craters, is consistent with its expected impact history. Overall, asteroid (52) Europa is still well modeled as a smooth triaxial ellipsoid with dimensions constrained by observations obtained over several apparitions.Comment: Accepted for publication in Icaru

Experiences of engaging with mental health services in 16- to 18-year-olds: an interpretative phenomenological analysis

Despite older adolescence being a risk period for the development of mental health concerns, mental health service engagement is low among 16- to 18-year-olds. As therapeutic attendance is linked to clinical outcome, it is important to understand engagement in this population. There is a paucity of research looking specifically at the older adolescent engagement phenomenon. Previous qualitative research into adolescent experiences has provided rich and detailed results. Interpretative phenomenological analysis was chosen as the methodological approach. Ten 16- to 18-year-olds were recruited from two London-based child and adolescent mental health services. Each young person was interviewed to understand his or her personal experience of engaging in mental health services, and associated engagement barriers and facilitators. Interviews were transcribed and underwent analysis. Analysis revealed ten subthemes subsumed within four superordinate themes: engagement begins at help seeking, strength of inner resolve, evolution of the self and in the clinic room. Themes are discussed in detail. Conclusions are drawn in relation to previous theory and research. When considering 16- to 18-year understandings of the engagement phenomena, key elements include clinician and service developmental appropriateness, negotiation of developmental tasks in relation to engagement, experience of the physical building environment, and awareness of service policy. Suggestions for clinical practice in relation to engagement facilitators and threat are made, and recommendations for future research proposed

Cooperativity in sandpiles: statistics of bridge geometries

Bridges form dynamically in granular media as a result of spatiotemporal inhomogeneities. We classify bridges as linear and complex, and analyse their geometrical characteristics. In particular, we find that the length distribution of linear bridges is exponential. We then turn to the analysis of the orientational distribution of linear bridges and find that, in three dimensions, they are {\it vertically diffusive but horizontally superdiffusive}; thus, when they exist, long linear bridges form `domes'. Our results are in good accord with Monte Carlo simulations of bridge structure; we make predictions for quantities that are experimentally accessible, and suggest that bridges are very closely related to force chains.Comment: 15 pages, 10 figures. Minor changes and update

Employment relations and social stratification in contemporary urban China: does Goldthorpe’s class theory still work?

Goldthorpe’s class theory suggests that social class arises from employment relations in industrialised societies. This article assesses whether class in urban China can be approached from the same perspective by addressing three issues: 1) whether employment relations can capture China’s class structure, 2) how differently class is shaped by occupational structure in China, and 3) how useful class is to help us understand income inequality. Based on a recent Chinese social survey, the analysis finds three clusters of Chinese employees that fit into the ‘service’, ‘intermediate’ and ‘labour contract’ class typologies suggested by Goldthorpe’s class theory. Also, there is evidence that class links to occupational structures in a similar way between Chinese and Western societies. Finally class, when directly measured from employment relations, displays a reasonable degree of explanatory power for inter-class income inequality whereas the Goldthorpe class classification fails to differentiate between intermediate and labour class positions

Psychophysiological processes of stress in chronic physical illness: a theoretical perspective

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75576/1/j.1365-2648.1990.tb01843.x.pd

Juggling Between Parental and School Expectations

We examined how perceived acculturation expectations from parents and school, and ethnic discrimination predicted early adolescents’ heritage and mainstream acculturation orientations at home (private domain) and in school (public domain) one year later. We surveyed 263 early adolescents of immigrant background in Germany (Mage = 10.44 years, 60% female). Multigroup path analyses revealed that perceived acculturation expectations and ethnic discrimination were more strongly related to adolescents’ private than public acculturation orientations. Parental heritage expectations were the strongest predictor of adolescents’ acculturation orientations. Boys were more susceptible than girls to ethnic discrimination and acculturation expectations in school, which affected their private and public acculturation orientations. Results highlight the importance of integrating domain-specific and gendered experiences when analyzing adolescents’ acculturative development

Economics of education research: a review and future prospects

In this paper we offer an appraisal of the economics of education research area, charting its history as a field and discussing the ways in which economists have contributed both to education research and to education policy-making. In particular, we highlight the theoretical and methodological contributions that economists have made to the field of education during the last 50 years. Despite the success of the economics of education as a field of inquiry, we argue that some of the contributions made by economists could be limited if the economics of education is seen as quite distinct from the other disciplines working in the field of education. In these areas of common interest, economists need to work side by side with the other major disciplines in the field of education if their contribution to the field is to be maximised, particularly in terms of applying improved methodology. We conclude that the study of education acquisition and its economic and social impact in the economics of education research area is very likely to remain a fertile research ground. Acknowledgement