Characteristics of students who enter occupational therapy education through the Universities and Colleges Admissions Service (UCAS) Clearing System

Since the 1960s, there has been substantial research outside the United Kingdom (UK) on recruitment to occupational therapy education. Recent UK studies have explored the characteristics of mature students (Craik and Alderman 1998), first-year students (Craik et al 2001) and students with a first degree (Craik and Napthine 2001). Based on these studies, a semi-structured, self-report, postal questionnaire gathered data from 50 students who entered the BSc(Hons) Occupational Therapy course at Brunel University, London, via the Universities and Colleges Admissions Service for the UK (UCAS) clearing system. The students tended to be younger and were more likely to be female and Caucasian and to have similar or higher academic qualifications than standardentry students at the same university. The majority first became aware of occupational therapy through previous work in a health care setting, although some did so while researching allied health professions. Although one-third originally had physiotherapy as their first career choice, 92% now considered that occupational therapy was what they wanted to do. The principal reason for applying through the clearing system was timing, with some applicants deciding late in the academic year to study occupational therapy. These findings add further weight to the need to promote the profession

Search for long lived charged massive particles in pp collisions at s-hat = 1.8TeV

We report a search for the production of long-lived charged massive particles in a data sample of 90   pb-1 of √s=1.8   TeV pp̅ collisions recorded by the Collider Detector at Fermilab. The search uses the muonlike penetration and anomalously high ionization energy loss signature expected for such a particle to discriminate it from backgrounds. The data are found to agree with background expectations, and cross section limits of O(1) pb are derived using two reference models, a stable quark and a stable scalar lepton

Research returns redux: a meta-analysis of the returns to agricultural R&D

A total of 294 studies of returns to agricultural R&D (including extension) were compiled and these studies provide 1,858 separate estimates of rates of return. This includes some extreme values, which are implausible. When the highest and lowest 2.5 percent of the rates of return were set aside, the estimated annual rates of return averaged 73 percent overall–88 percent for research only, 45 percent for research and extension, and 79 percent for extension only. But these averages reveal little meaningful information from a large and diverse body of literature, which provides rate-of-return estimates that are often not directly comparable. The purpose of this study was to go behind the averages, and try to account for the sources of differences, in a meta-analysis of the studies of returns to agricultural R&D. The results conform with the theory and prior beliefs in many ways. Several features of the methods used by research evaluators matter, in particular assumptions about lag lengths and the nature of the research-induced supply shift.Rate of return., Agricultural research.,

A meta-analysis of rates of return to agricultural R & D: ex pede Herculem?

IFPRI has long argued that spending on agricultural research constitutes a sound investment in poverty reduction and agricultural and economic growth, through improvements in productivity. This argument is based partly on the reported evidence of high rates of return to agricultural research, typically believed to be in the range of 40–60 percent per year. Yet there continues to be controversy over whether these figures are to be believed, and over what they actually indicate. This study represents the first attempt to take a comprehensive look at all the available evidence on rates of return to investments in agricultural R&D since 1953, and the only attempt to do so in a formal statistical fashion. This report has compiled and documented the literature in ways that make it more accessible and more useful to other researchers and policymakers, as well as others interested in the evidence. The analysis reveals some systematic patterns and some sources of biases that make it easier to interpret the evidence and draw meaningful conclusions. (Excerpted from Summary by Per Pinstrup-Andersen)Development projects Evaluation., Agricultural research, Statistics., Agricultural economics and policies,

Debris disk size distributions: steady state collisional evolution with P-R drag and other loss processes

We present a new scheme for determining the shape of the size distribution, and its evolution, for collisional cascades of planetesimals undergoing destructive collisions and loss processes like Poynting-Robertson drag. The scheme treats the steady state portion of the cascade by equating mass loss and gain in each size bin; the smallest particles are expected to reach steady state on their collision timescale, while larger particles retain their primordial distribution. For collision-dominated disks, steady state means that mass loss rates in logarithmic size bins are independent of size. This prescription reproduces the expected two phase size distribution, with ripples above the blow-out size, and above the transition to gravity-dominated planetesimal strength. The scheme also reproduces the expected evolution of disk mass, and of dust mass, but is computationally much faster than evolving distributions forward in time. For low-mass disks, P-R drag causes a turnover at small sizes to a size distribution that is set by the redistribution function (the mass distribution of fragments produced in collisions). Thus information about the redistribution function may be recovered by measuring the size distribution of particles undergoing loss by P-R drag, such as that traced by particles accreted onto Earth. Although cross-sectional area drops with 1/age^2 in the PR-dominated regime, dust mass falls as 1/age^2.8, underlining the importance of understanding which particle sizes contribute to an observation when considering how disk detectability evolves. Other loss processes are readily incorporated; we also discuss generalised power law loss rates, dynamical depletion, realistic radiation forces and stellar wind drag.Comment: Accepted for publication by Celestial Mechanics and Dynamical Astronomy (special issue on EXOPLANETS

Collisional modelling of the AU Microscopii debris disc

The spatially resolved AU Mic debris disc is among the most famous and best-studied debris discs. We aim at a comprehensive understanding of the dust production and the dynamics of the disc objects with in depth collisional modelling including stellar radiative and corpuscular forces. Our models are compared to a suite of observational data for thermal and scattered light emission, ranging from the ALMA radial surface brightness profile at 1.3mm to polarisation measurements in the visible. Most of the data can be reproduced with a planetesimal belt having an outer edge at around 40au and subsequent inward transport of dust by stellar winds. A low dynamical excitation of the planetesimals with eccentricities up to 0.03 is preferred. The radial width of the planetesimal belt cannot be constrained tightly. Belts that are 5au and 17au wide, as well as a broad 44au-wide belt are consistent with observations. All models show surface density profiles increasing with distance from the star as inferred from observations. The best model is achieved by assuming a stellar mass loss rate that exceeds the solar one by a factor of 50. While the SED and the shape of the ALMA profile are well reproduced, the models deviate from the scattered light data more strongly. The observations show a bluer disc colour and a lower degree of polarisation for projected distances <40au than predicted by the models. The problem may be mitigated by irregularly-shaped dust grains which have scattering properties different from the Mie spheres used. From tests with a handful of selected dust materials, we derive a preference for mixtures of silicate, carbon, and ice of moderate porosity. We address the origin of the unresolved central excess emission detected by ALMA and show that it cannot stem from an additional inner belt alone. Instead, it should derive, at least partly, from the chromosphere of the central star.Comment: Astronomy and Astrophysics (accepted for publication), 18 pages, 11 figure