1,580 research outputs found
A five year programme for radioisotope production at the Research Establishment.
This report summarises plans for radioisotope production at Lucas Heights over the period 1966-71 and indicates how these are based on present trends of demand for radioisotopes. The programme is discussed in terms of available staff and facilities; while some small staff increases will be required, the facilities presently being commissioned should be adequate over this period
A comparison of walk-in counselling and the wait list model for delivering counselling services
Background: Walk-in counselling has been used to reduce wait times but there are few controlled studies to compare outcomes between walk-in and the traditional model of service delivery.
Aims: To compare change in psychological distress by clients receiving services from two models of service delivery, a walk-in counselling model and a traditional counselling model involving a wait list
Method: Mixed methods sequential explanatory design including quantitative comparison of groups with one pre-test and two follow ups, and qualitative analysis of interviews with a subsample. 524 participants 16 years and older were recruited from two Family Counselling Agencies; the General Health Questionnaire assessed change in psychological distress; prior use of other mental health and instrumental services was also reported.
Results: Hierarchical linear modelling revealed clients of the walk-in model improved faster and were less distressed at the 4-week follow-up compared to the traditional service delivery model. At the 10-week follow-up, both groups had improved and were similar. Participants receiving instrumental services prior to baseline improved more slowly. Qualitative interviews confirmed participants valued the accessibility of the walk-in model.
Conclusions: This study improves methodologically on previous studies of walk-in counselling, an approach to service delivery that is not conducive to randomized controlled trials
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Performance-based building and innovation: Balancing client and industry needs
One reason for the interest in performance-based building is that it is commonly advocated as a powerful way of enhancing innovation performance by articulating building performance outcomes, and by offering relevant procurement actors the discretion to innovate to meet these performance requirements more effectively and/or efficiently. The paper argues that the current approach to performance-based building assumes that relevant actors have the capacity, ability and motivation to innovate from a business perspective. It is proposed that the prevailing conceptualization of PBB is too restrictive and should be broadened explicitly to accommodate the required business logic that must be in place before actors will innovate. The relevant performance-based building and innovation literature is synthesized to support the assertion. The paper concludes with an innovation-focused definition of performance-based building
Your space or mine? : Mapping self in time
Peer reviewedPublisher PD
Lyman Alpha Blobs as an Observational Signature of Cold Accretion Streams into Galaxies
Recent hydrodynamic simulations of galaxy formation reveal streams of cold (T
~ 1e4 K) gas flowing into the centers of dark matter halos as massive as
1e12-1e13.5 M_sun at redshifts z~1-3. In this paper we show that if > 20% of
the gravitational binding energy of the gas is radiated away, then the
simulated cold flows are spatially extended Lyman Alpha (Lya) sources with
luminosities, Lya line widths, and number densities that are comparable to
those of observed Lya blobs. Furthermore, the filamentary structure of the cold
flows can explain the wide range of observed Lya blob morphologies. Since the
most massive halos form in dense environments, the association of Lya blobs
with overdense regions arise naturally. We argue that Lya blobs - even those
which are clearly associated with starburst galaxies or quasars - provide
direct observational support for the cold accretion mode of galaxies. We
discuss various testable predictions of this association.Comment: MNRAS in press. 13 pages, 6 figures. Discussion + references added.
Main conclusions unaffecte
Efficient and Unbiased Estimation of Population Size
Population sizing from still aerial pictures is of wide applicability in ecological and social sciences. The problem is long standing because current automatic detection and counting algorithms are known to fail in most cases, and exhaustive manual counting is tedious, slow, difficult to verify and unfeasible for large populations. An alternative is to multiply population density with some reference area but, unfortunately, sampling details, handling of edge effects, etc., are seldom described. For the first time we address the problem using principles of geometric sampling. These principles are old and solid, but largely unknown outside the areas of three dimensional microscopy and stereology. Here we adapt them to estimate the size of any population of individuals lying on an essentially planar area, e.g. people, animals, trees on a savanna, etc. The proposed design is unbiased irrespective of population size, pattern, perspective artifacts, etc. The implementation is very simple—it is based on the random superimposition of coarse quadrat grids. Also, an objective error assessment is often lacking. For the latter purpose the quadrat counts are often assumed to be independent. We demonstrate that this approach can perform very poorly, and we propose (and check via Monte Carlo resampling) a new theoretical error prediction formula. As far as efficiency, counting about 50 (100) individuals in 20 quadrats, can yield relative standard errors of about 8% (5%) in typical cases. This fact effectively breaks the barrier hitherto imposed by the current lack of automatic face detection algorithms, because semiautomatic sampling and manual counting becomes an attractive option
Issues in the Pharmacokinetics of Trichloroethylene and Its Metabolites
Much progress has been made in understanding the complex pharmacokinetics of trichloroethylene (TCE). Qualitatively, it is clear that TCE is metabolized to multiple metabolites either locally or into systemic circulation. Many of these metabolites are thought to have toxicologic importance. In addition, efforts to develop physiologically based pharmacokinetic (PBPK) models have led to a better quantitative assessment of the dosimetry of TCE and several of its metabolites. As part of a mini-monograph on key issues in the health risk assessment of TCE, this article is a review of a number of the current scientific issues in TCE pharmacokinetics and recent PBPK modeling efforts with a focus on literature published since 2000. Particular attention is paid to factors affecting PBPK modeling for application to risk assessment. Recent TCE PBPK modeling efforts, coupled with methodologic advances in characterizing uncertainty and variability, suggest that rigorous application of PBPK modeling to TCE risk assessment appears feasible at least for TCE and its major oxidative metabolites trichloroacetic acid and trichloroethanol. However, a number of basic structural hypotheses such as enterohepatic recirculation, plasma binding, and flow- or diffusion-limited treatment of tissue distribution require additional evaluation and analysis. Moreover, there are a number of metabolites of potential toxicologic interest, such as chloral, dichloroacetic acid, and those derived from glutathione conjugation, for which reliable pharmacokinetic data is sparse because of analytical difficulties or low concentrations in systemic circulation. It will be a challenge to develop reliable dosimetry for such cases
A Framework for Formal Modeling and Analysis of Organizations
A new, formal, role-based, framework for modeling and analyzing both real world and artificial organizations is introduced. It exploits static and dynamic properties of the organizational model and includes the (frequently ignored) environment. The transition is described from a generic framework of an organization to its deployed model and to the actual agent allocation. For verification and validation of the proposed model, a set of dedicated techniques is introduced. Moreover, where most computational models can handle only two or three layered organizational structures, our framework can handle any arbitrary number of organizational layers. Henceforth, real-world organizations can be modeled and analyzed, as illustrated by a case study, within the DEAL project line. © Springer Science+Business Media, LLC 2007
Methodological criteria for the assessment of moderators in systematic reviews of randomised controlled trials : a consensus study
Background: Current methodological guidelines provide advice about the assessment of sub-group analysis within
RCTs, but do not specify explicit criteria for assessment. Our objective was to provide researchers with a set of
criteria that will facilitate the grading of evidence for moderators, in systematic reviews.
Method: We developed a set of criteria from methodological manuscripts (n = 18) using snowballing technique,
and electronic database searches. Criteria were reviewed by an international Delphi panel (n = 21), comprising
authors who have published methodological papers in this area, and researchers who have been active in the
study of sub-group analysis in RCTs. We used the Research ANd Development/University of California Los Angeles
appropriateness method to assess consensus on the quantitative data. Free responses were coded for consensus
and disagreement. In a subsequent round additional criteria were extracted from the Cochrane Reviewers’
Handbook, and the process was repeated.
Results: The recommendations are that meta-analysts report both confirmatory and exploratory findings for subgroups
analysis. Confirmatory findings must only come from studies in which a specific theory/evidence based apriori
statement is made. Exploratory findings may be used to inform future/subsequent trials. However, for
inclusion in the meta-analysis of moderators, the following additional criteria should be applied to each study:
Baseline factors should be measured prior to randomisation, measurement of baseline factors should be of
adequate reliability and validity, and a specific test of the interaction between baseline factors and interventions
must be presented.
Conclusions: There is consensus from a group of 21 international experts that methodological criteria to assess
moderators within systematic reviews of RCTs is both timely and necessary. The consensus from the experts
resulted in five criteria divided into two groups when synthesising evidence: confirmatory findings to support
hypotheses about moderators and exploratory findings to inform future research. These recommendations are
discussed in reference to previous recommendations for evaluating and reporting moderator studies
Predictors of patient preference for either whole body magnetic resonance imaging (WB-MRI) or CT/ PET-CT for staging colorectal or lung cancer.
INTRODUCTION: Whole body magnetic resonance imaging (WB-MRI) may be more efficient in staging cancers, but can be harder for patients to tolerate. We examined predictors of patient preference for WB-MRI vs. CT/ PET-CT for staging colorectal or lung cancer. METHODS: Patients recruited prospectively to two multicentre trials comparing diagnostic accuracy of WB-MRI with standard staging scans were sent two questionnaires: the first, administered at trial registration, captured demographics, educational level and comorbidities; the second, administered after staging completion, measured emotional distress (GHQ-12), positive mood (PANAS), perceived scan burden, patients' beliefs about WB-MRI, and preference for either WB-MRI or CT (colorectal trial), WB-MRI or PET-CT (lung trial). Preference for WB-MRI or CT/ PET-CT was analysed using logistic regression. RESULTS: Baseline and post-staging questionnaires were completed by 97 and 107 patients, respectively. Overall, 56/107 (52%) preferred WB-MRI over standard scans and were more likely to have no additional comorbidities, higher positive mood, greater awareness of potential benefits of WB-MRI and lower levels of perceived WB-MRI scan burden. In adjusted analyses, only awareness of potential WB-MRI benefits remained a significant predictor (OR: 1.516, 95% CIs 1.006-2.284, P = 0.047). Knowledge that WB-MRI does not use radiation predicted preference (adjusted OR: 3.018, 95% CIs 1.099-8.288, P = 0.032), although only 45/107 (42%) patients were aware of this attribute. CONCLUSIONS: A small majority of patients undergoing staging of colorectal or lung cancer prefer WB-MRI to CT/ PET-CT. Raising awareness of the potential benefits of WB-MRI, notably lack of ionizing radiation, could influence preference
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