172 research outputs found
Response of the Agile Antechinus to Habitat Edge, Configuration and Condition in Fragmented Forest
Habitat fragmentation and degradation seriously threaten native animal communities. We studied the response of a small marsupial, the agile antechinus Antechinus agilis, to several environmental variables in anthropogenically fragmented Eucalyptus forest in south-east Australia. Agile antechinus were captured more in microhabitats dominated by woody debris than in other microhabitats. Relative abundances of both sexes were positively correlated with fragment core area. Male and female mass-size residuals were smaller in larger fragments. A health status indicator, haemoglobin-haematocrit residuals (HHR), did not vary as a function of any environmental variable in females, but male HHR indicated better health where sites' microhabitats were dominated by shrubs, woody debris and trees other than Eucalyptus. Females were trapped less often in edge than interior fragment habitat and their physiological stress level, indicated by the neutrophil/lymphocyte ratio in peripheral blood, was higher where fragments had a greater proportion of edge habitat. The latter trend was potentially due to lymphopoenia resulting from stress hormone-mediated leukocyte trafficking. Using multiple indicators of population condition and health status facilitates a comprehensive examination of the effects of anthropogenic disturbances, such as habitat fragmentation and degradation, on native vertebrates. Male agile antechinus' health responded negatively to habitat degradation, whilst females responded negatively to the proportion of edge habitat. The health and condition indicators used could be employed to identify conservation strategies that would make habitat fragments less stressful for this or similar native, small mammals
Faking and the Validity of Personality Tests: An Experimental Investigation Using Modern Forced Choice Measures
Despite the established validity of personality measures for personnel selection, their susceptibility to faking has been a persistent concern. However, the lack of studies that combine generalizability with experimental control makes it difficult to determine the effects of applicant faking. This study addressed this deficit in two ways. First, we compared a subtle incentive to fake with the explicit “fake-good” instructions used in most faking experiments. Second, we compared standard Likert scales to multidimensional forced choice (MFC) scales designed to resist deception, including more and less fakable versions of the same MFC inventory. MFC scales substantially reduced motivated score elevation but also appeared to elicit selective faking on work-relevant dimensions. Despite reducing the effectiveness of impression management attempts, MFC scales did not retain more validity than Likert scales when participants faked. However, results suggested that faking artificially bolstered the criterion-related validity of Likert scales while diminishing their construct validity
The host galaxies of luminous quasars
We present results of a deep HST/WFPC2 imaging study of 17 quasars at z~0.4,
designed to determine the properties of their host galaxies. The sample
consists of quasars with absolute magnitudes in the range -24>M_V>-28, allowing
us to investigate host galaxy properties across a decade in quasar luminosity,
but at a single redshift. We find that the hosts of all the RLQs, and all the
RQQs with nuclear luminosities M_V<-24, are massive bulge-dominated galaxies,
confirming and extending the trends deduced from our previous studies. From the
best-fitting model host galaxies we have estimated spheroid and black-hole
masses, and the efficiency (with respect to Eddington luminosity) with which
each quasar is radiating. The largest inferred black-hole mass in our sample is
\~3.10^9 M_sun, comparable to those at the centres of M87 and Cygnus A. We find
no evidence for super-Eddington accretion in even the most luminous objects. We
investigate the role of scatter in the black-hole:spheroid mass relation in
determining the ratio of quasar to host-galaxy luminosity, by generating
simulated populations of quasars lying in hosts with a Schechter mass function.
Within the subsample of the highest luminosity quasars, the observed variation
in nuclear-host luminosity ratio is consistent with being the result of the
scatter in the black-hole:spheroid relation. Quasars with high nuclear-host
ratios can be explained by sub-Eddington accretion onto black holes in the
high-mass tail of the black-hole:spheroid relation. Our results imply that,
owing to the Schechter cutoff, host mass should not continue to increase
linearly with quasar luminosity, at the very highest luminosities. Any quasars
more luminous than M_V=-27 should be found in massive elliptical hosts which at
the present day would have M_V ~ -24.5.Comment: Accepted for publication in MNRAS. 18 pages; 7 figures and 17
greyscale images are reproduced here at low quality due to space limitations.
High-resolution figures are available from
ftp://ftp.roe.ac.uk/pub/djef/preprints/floyd2004
Natural Variation in Interleukin-2 Sensitivity Influences Regulatory T-Cell Frequency and Function in Individuals With Long-standing Type 1 Diabetes.
Defective immune homeostasis in the balance between FOXP3+ regulatory T cells (Tregs) and effector T cells is a likely contributing factor in the loss of self-tolerance observed in type 1 diabetes (T1D). Given the importance of interleukin-2 (IL-2) signaling in the generation and function of Tregs, observations that polymorphisms in genes in the IL-2 pathway associate with T1D and that some individuals with T1D exhibit reduced IL-2 signaling indicate that impairment of this pathway may play a role in Treg dysfunction and the pathogenesis of T1D. Here, we have examined IL-2 sensitivity in CD4+ T-cell subsets in 70 individuals with long-standing T1D, allowing us to investigate the effect of low IL-2 sensitivity on Treg frequency and function. IL-2 responsiveness, measured by STAT5a phosphorylation, was a very stable phenotype within individuals but exhibited considerable interindividual variation and was influenced by T1D-associated PTPN2 gene polymorphisms. Tregs from individuals with lower IL-2 signaling were reduced in frequency, were less able to maintain expression of FOXP3 under limiting concentrations of IL-2, and displayed reduced suppressor function. These results suggest that reduced IL-2 signaling may be used to identify patients with the highest Treg dysfunction and who may benefit most from IL-2 immunotherapy.This work was supported by the JDRF UK Centre for Diabetes Genes, Autoimmunity and Prevention (D-GAP; 4-2007-1003), the Wellcome Trust (WT061858/091157) and the NIHR Cambridge Biomedical Research Centre (CBRC). The Cambridge Institute for Medical Research (CIMR) is in receipt of a Wellcome Trust Strategic Award (100140).This is the author accepted manuscript. The final version is available from the American Diabetes Association via http://dx.doi.org/10.2337/db15-051
Individual differences in loss aversion: conscientiousness predicts how life satisfaction responds to losses versus gains in income
Loss aversion is considered a general pervasive bias occurring regardless of context or person making the decision. We hypothesized that conscientiousness would predict an aversion to losses in the financial domain. We index loss aversion by the relative impact of income losses and gains on life satisfaction. In a representative German sample (N¬ = 105,558: replicated in a British sample, N = 33,848), with conscientiousness measured at baseline, those high on conscientiousness have the strongest reactions to income losses, suggesting a pronounced loss aversion effect, whilst for those moderately un-conscientious there is no loss aversion effect. Our research; (a) provides the first evidence of personality moderation of any loss aversion phenomena; (b) supports contextual perspectives that both personality and situational factors need to be examined in combination; (c) shows that the small but robust relationship with life satisfaction is primarily driven by a subset of people experiencing highly impactful losses
Changes in cortical and striatal neurons predict behavioral and electrophysiological abnormalities in a transgenic murine model of Huntington\u27s disease
Neurons in Huntington\u27s disease exhibit selective morphological and subcellular alterations in the striatum and cortex. The link between these neuronal changes and behavioral abnormalities is unclear. We investigated relationships between essential neuronal changes that predict motor impairment and possible involvement of the corticostriatal pathway in developing behavioral phenotypes. We therefore generated heterozygote mice expressing the N-terminal one-third of huntingtin with normal (CT18) or expanded (HD46, HD100) glutamine repeats. The HD mice exhibited motor deficits between 3 and 10 months. The age of onset depended on an expanded polyglutamine length; phenotype severity correlated with increasing age. Neuronal changes in the striatum (nuclear inclusions) preceded the onset of phenotype, whereas cortical changes, especially the accumulation of huntingtin in the nucleus and cytoplasm and the appearance of dysmorphic dendrites, predicted the onset and severity of behavioral deficits. Striatal neurons in the HD mice displayed altered responses to cortical stimulation and to activation by the excitotoxic agent NMDA. Application of NMDA increased intracellular Ca(2+) levels in HD100 neurons compared with wild-type neurons. Results suggest that motor deficits in Huntington\u27s disease arise from cumulative morphological and physiological changes in neurons that impair corticostriatal circuitry
Academic requirements for Certificate of Completion of Training in surgical training: Consensus recommendations from the Association of Surgeons in Training/National Research Collaborative Consensus Group.
BACKGROUND: Surgical trainees are expected to demonstrate academic achievement in order to obtain their certificate of completion of training (CCT). These standards are set by the Joint Committee on Surgical Training (JCST) and specialty advisory committees (SAC). The standards are not equivalent across all surgical specialties and recognise different achievements as evidence. They do not recognise changes in models of research and focus on outcomes rather than process. The Association of Surgeons in Training (ASiT) and National Research Collaborative (NRC) set out to develop progressive, consistent and flexible evidence set for academic requirements at CCT. METHODS: A modified-Delphi approach was used. An expert group consisting of representatives from the ASiT and the NRC undertook iterative review of a document proposing changes to requirements. This was circulated amongst wider stakeholders. After ten iterations, an open meeting was held to discuss these proposals. Voting on statements was performed using a 5-point Likert Scale. Each statement was voted on twice, with ≥80% of votes in agreement meaning the statement was approved. The results of this vote were used to propose core and optional academic requirements for CCT. RESULTS: Online discussion concluded after ten rounds. At the consensus meeting, statements were voted on by 25 delegates from across surgical specialties and training-grades. The group strongly favoured acquisition of 'Good Clinical Practice' training and research methodology training as CCT requirements. The group agreed that higher degrees, publications in any author position (including collaborative authorship), recruiting patients to a study or multicentre audit and presentation at a national or international meeting could be used as evidence for the purpose of CCT. The group agreed on two essential 'core' requirements (GCP and methodology training) and two of a menu of four 'additional' requirements (publication with any authorship position, presentation, recruitment of patients to a multicentre study and completion of a higher degree), which should be completed in order to attain CCT. CONCLUSION: This approach has engaged stakeholders to produce a progressive set of academic requirements for CCT, which are applicable across surgical specialties. Flexibility in requirements whilst retaining a high standard of evidence is desirable
Transmission Dynamics of Methicillin-Resistant Staphylococcus aureus in a Medical Intensive Care Unit in India
Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a global pathogen and an important but seldom investigated cause of morbidity and mortality in lower and middle-income countries where it can place a major burden on limited resources. Quantifying nosocomial transmission in resource-poor settings is difficult because molecular typing methods are prohibitively expensive. Mechanistic statistical models can overcome this problem with minimal cost. We analyse the transmission dynamics of MRSA in a hospital in south India using one such approach and provide conservative estimates of the organism's economic burden. Methods and Findings: Fifty months of MRSA infection data were collected retrospectively from a Medical Intensive Care Unit (MICU) in a tertiary hospital in Vellore, south India. Data were analysed using a previously described structured hidden Markov model. Seventy-two patients developed MRSA infections and, of these, 49 (68%) died in the MICU. We estimated that 4.2% (95%CI 1.0, 19.0) of patients were MRSA-positive when admitted, that there were 0.39 MRSA infections per colonized patient month (0.06, 0.73), and that the ward-level reproduction number for MRSA was 0.42 (0.08, 2.04). Anti-MRSA antibiotic treatment costs alone averaged $124/patient, over three times the monthly income of more than 40% of the Indian population. Conclusions: Our analysis of routine data provides the first estimate of the nosocomial transmission potential of MRSA in India. The high levels of transmission estimated underline the need for cost-effective interventions to reduce MRSA transmission in hospital settings in low and middle income countries. © 2011 Christopher et al
InterMEL: An international biorepository and clinical database to uncover predictors of survival in early-stage melanoma
We are conducting a multicenter study to identify classifiers predictive of disease-specific
survival in patients with primary melanomas. Here we delineate the unique aspects, challenges, and best practices for optimizing a study of generally small-sized pigmented tumor
samples including primary melanomas of at least 1.05mm from AJTCC TNM stage IIA-IIID
patients. We also evaluated tissue-derived predictors of extracted nucleic acids’ quality and
success in downstream testing. This ongoing study will target 1,000 melanomas within the
international InterMEL consortium.Medicin
Basic Atomic Physics
Contains reports on five research projects.National Science Foundation Grant PHY 89-19381U.S. Navy - Office of Naval Research Contract N00014-90-J-1322Joint Services Electronics Program Contract DAAL03-89-C-0001Joint Services Electronics Program Contract DAAL03-92-C-0001U.S. Army Research Office Contract DAAL03-89-K-0082U.S. Navy - Office of Naval Research Grant N00014-89-J-1207U.S. Navy - Office of Naval Research Grant N00014-90-J-1642National Science Foundation Grant PHY 86-05893National Science Foundation Grant PHY 89-2176
- …