Neutrons from 9Be/alpha,n/ reaction for E alpha between 6 and 10 MeV

Neutron energy spectra measured as function of neutron emission angle and ion bombardment energ

INTERDISCIPLINARY VARIATIONS IN THE PERCEPTION OF POWER: A STUDY IN IDEOLOGY

There have been marked disagreements in the literature on the structure of power in American society. The authors suggest that this controversy is an artifact of ideological differences between sociologists and political scientists. This hypothesis is tested through the use of a pluralism-elitism scale. Political scientists are found to score toward the pluralistic end of the spectrum, while sociologists are concentrated toward the elitist end, thus providing preliminary support for the hypothesis

Rhizon Sampling of Pore Waters on Scientific Drilling Expeditions: An Example from the IODP Expedition 302, Arctic Coring Expedition (ACEX)

No abstract available. doi:10.2204/iodp.sd.4.08.2007</a

Cooling Flows and Metallicity Gradients in Clusters of Galaxies

The X-ray emission by hot gas at the centers of clusters of galaxies is commonly modeled assuming the existence of steady-state, inhomogeneous cooling flows. We derive the metallicity profiles of the intracluster medium expected from such models. The inflowing gas is chemically enriched by type Ia supernovae and stellar mass loss in the outer parts of the central galaxy, which may give rise to a substantial metallicity gradient. The amplitude of the expected metallicity enhancement towards the cluster center is proportional to the ratio of the central galaxy luminosity to the mass inflow rate. The metallicity of the hotter phases is expected to be higher than that of the colder, denser phases. The metallicity profile expected for the Centaurus cluster is in good agreement with the metallicity gradient recently inferred from ASCA measurements (Fukazawa et al. 1994). However, current data do not rule out alternative models where cooling is balanced by some heat source. The metallicity gradient does not need to be present in all clusters, depending on the recent merging history of the gas around the central cluster galaxy, and on the ratio of the stellar mass in the central galaxy to the gas mass in the cooling flow.Comment: uuencoded postscript, 8 pages of text + 2 figures, accepted by The Astrophysical Journal (Letters

Abundances of Red Giants in the Andromeda II Dwarf Spheroidal Galaxy

We have obtained spectra for 50 candidate red giants in Andromeda II (a dwarf spheroidal companion of M31) using LRIS on the Keck II telescope. After eliminating background galaxies and Galactic foreground stars, we are left with a sample of 42 red giants for which membership in Andromeda II can be established unambiguously from radial velocities. Line indices measured on the Lick/IDS system are combined with V and I photometry obtained with the Keck II and Palomar 5m telescopes to investigate the age and metallicity distribution of these stars. Based on a comparison of the measured line indices to those of Lick/IDS standard stars in globular and open clusters, we derive a mean metallicity of [Fe/H] = -1.47+/-0.19 dex. This confirms earlier conclusions based on Thuan-Gunn gr photometry that Andromeda II obeys the familiar relation between mean stellar metallicity and galaxy luminosity. There is also evidence for a dispersion in metallicity of 0.35+/-0.10 dex based on the scatter in the measured Mgb line indices and the observed width of the galaxy's giant branch. Although existing observations of Local Group dwarf galaxies indicate that their mean stellar metallicity depends rather sensitively on host galaxy absolute magnitude, the internal spread in metallicity appears to be relatively independent of luminosity. Finally, a small number of stars are found above the Population II red giant branch, indicating the presence of a modest intermediate-age population in this galaxy. (ABRIDGED)

The covid-19 learning crisis as a challenge and an opportunity for schools: An evidence review and conceptual synthesis of research-based tools for sustainable change

This paper advances our understanding of how schools can become change agents capable of transforming local practice to address the challenges arising from the Covid-19 pandemic. It presents a novel application of cultural-historical activity theory to reinterpret evidence on widespread learning loss and increasing educational inequities resulting from the pandemic, and to identify scalable transformative learning opportunities through reframing the crisis as a double stimulation. By reviewing evidence of the emerging educational landscape, we first develop a picture of the new ‘problem space’ upon which schools must act. We develop a problem space map to serve as the first stimulus to articulate local challenges. Integrating this problem space with research on professional change, we identify conceptual tools to capture learning gaps and implement pedagogic interventions at scale, in order to enhance schools’ agency in directly addressing the crisis. These tools can act as the second stimulus, enabling educators to address local challenges. We conclude by discussing the Covid-19 educational crisis as a unique stimulus for professional learning and outline the potential for durable shifts in educational thinking and practice beyond the pandemic. We argue that this unprecedented historic disruption can be harnessed as a transformative professional learning opportunity. In particular, we consider how research on professional change offers local, scalable interventions and tools that can support educators in preventing the new insights from ‘slipping away’ post-pandemic. Utilising the notions of boundaries and tool-mediated professional change, we examine the ways in which this disruption generates opportunities to envision alternative futures for equitable learning in school.Author 1: The epiSTEMe project [grant number RES-179-25-0003, PI Prof. K. Ruthven] The TEACh project [ES/M005445/1, PI Prof. P. Rose] ESRC Impact Acceleration Grant, University of Cambridge [PI Dr. R. Hofmann] Cambridge University Health Partners Commonwealth Education Trust (PI. Prof. S. Hennessy) Authors 2-8: (2) Faculty of Education, University of Cambridge, PhD scholarship (3) Economic and Social Research Council PhD scholarship [ES/P000738/1] (4) Agencia Nacional de Investigación y Desarrollo (ANID), Cambridge Trust, PhD scholarship (5) Economic and Social Research Council [ES/P000738/1] and MRC Epidemiology Unit PhD scholarship (6) Yayasan Khazanah, Cambridge Trust, PhD scholarship (7) Guy’s and St Thomas’ Charity, UK [TCF180902] PhD scholarship (8) The LEGO Foundatio

Mental health in UK Biobank - development, implementation and results from an online questionnaire completed by 157 366 participants: a reanalysis

Background UK Biobank is a well-characterised cohort of over 500 000 participants including genetics, environmental data and imaging. An online mental health questionnaire was designed for UK Biobank participants to expand its potential. Aims Describe the development, implementation and results of this questionnaire. Method An expert working group designed the questionnaire, using established measures where possible, and consulting a patient group. Operational criteria were agreed for defining likely disorder and risk states, including lifetime depression, mania/hypomania, generalised anxiety disorder, unusual experiences and self-harm, and current post-traumatic stress and hazardous/harmful alcohol use. Results A total of 157 366 completed online questionnaires were available by August 2017. Participants were aged 45–82 (53% were ≥65 years) and 57% women. Comparison of self-reported diagnosed mental disorder with a contemporary study shows a similar prevalence, despite respondents being of higher average socioeconomic status. Lifetime depression was a common finding, with 24% (37 434) of participants meeting criteria and current hazardous/harmful alcohol use criteria were met by 21% (32 602), whereas other criteria were met by less than 8% of the participants. There was extensive comorbidity among the syndromes. Mental disorders were associated with a high neuroticism score, adverse life events and long-term illness; addiction and bipolar affective disorder in particular were associated with measures of deprivation. Conclusions The UK Biobank questionnaire represents a very large mental health survey in itself, and the results presented here show high face validity, although caution is needed because of selection bias. Built into UK Biobank, these data intersect with other health data to offer unparalleled potential for crosscutting biomedical research involving mental health