bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of a hypercaloric diet on β‐cell responsivity in lean healthy men
Authors: Brands Myrte , Swat Maciej , Lammers Nicolette M. , Sauerwein Hans P. , Endert Erik , Ackermans Mariëtte T. , Verhoeven Arthur J. , Serlie Mireille J. 
Published: February 2012

SummaryObjectiveInsulin resistance and hyperinsulinaemia precede the onset of obesity‐induced DM2. The early adaptation of the β‐cell during the initial phase of overfeeding and weight gain has only been partly elucidated. We studied the early changes in insulin clearance and β‐cell responsivity during a positive and negative energy balance in lean healthy men.DesignWe studied in nine healthy lean men [age, 37 (27–43) years; BMI, 23·6 (20·6–25·6) kg/m2] insulin sensitivity, insulin clearance, insulin secretion and static and dynamic β‐cell responsivity at baseline and after the hypercaloric and subsequent hypocaloric diet.ResultsParticipants gained 7 [5·1–7·6]% of their initial body weight on the hypercaloric diet. Compared to baseline, insulin sensitivity and insulin clearance decreased, while glucose‐stimulated insulin secretion was higher. The GLP‐1 response to oral glucose did not change. The dynamic β‐cell responsivity index increased but the basal and static responsivity indexes did not change. Total and static disposition indexes (DIs) in the hypercaloric state showed a trend towards a decrease. During the hypocaloric diet, insulin sensitivity, glucose‐stimulated insulin secretion and insulin clearance returned to baseline. The responsivity and the DIs were not different in the hypocaloric phase compared to baseline.ConclusionA positive energy balance resulting in weight gain in lean men induces hyperinsulinaemia, which is explained by a combined effect on insulin clearance and insulin secretion. Increased insulin secretion was related to insulin resistance‐induced higher glucose concentrations but also to increased dynamic β‐cell responsivity. Glucose sensitivity of the β‐cell did not change. These early adaptations are completely reversible during a negative energy balance after loss of the gained weight.
Pravastatin and simvastatin improves acetylsalicylic acid‐mediated in vitro blood platelet inhibition
Authors: Luzak Boguslawa , Rywaniak Joanna , Stanczyk Lidia , Watala Cezary 
Published: February 2012

Eur J Clin Invest 2012AbstractBackground  Insight into the pathophysiology of atherothrombosis indicates that an integrated risk factor approach, focusing particularly on the management of dyslipidaemia (with statins) and thrombosis (with ASA), may constitute an optimal therapeutic approach. We investigated whether pravastatin, simvastatin and atorvastatin may directly modulate under in vitro conditions the reactivity of blood platelets originating from healthy volunteers. In addition, we analysed the influence of statins on the platelet sensitivity to ASA under such conditions.Materials and methods  We monitored collagen‐ or ADP‐induced platelet aggregation, CD36, PAC‐1 and CD62 expression on platelet surface and thromboxane generation after incubation with pravastatin, simvastatin, atorvastatin and/or ASA.Results  The incubation of whole blood with simvastatin and pravastatin significantly decreased CD36 expression. In the presence of 50 μM ASA, simvastatin and pravastatin significantly reduced the PAC‐1 expression (30% reduction for simvastatin, P < 0·01, and 15% reduction for pravastatin, P < 0·01), platelet aggregation (20% reduction for both statins, P < 0·01) and thromboxane generation (35% reduction for simvastatin, P < 0·001, and 30% reduction for pravastatin, P < 0·001) compared to ASA alone. Atorvastatin changed neither baseline platelet aggregation nor ASA‐mediated platelet inhibition.Conclusions  Our results suggested that statins may directly interact with platelet membranes or may modulate a signalling pathway in platelets (the pleiotropic effects of statins). It is possible that the statin effect on CD36 and ASA‐mediated protein acetylation can be reached by the modulation of a distribution or a function of membrane‐associated proteins. Further studies are certainly needed to better elucidate the mechanism(s) underlying the statins’ effects on platelet sensitivity to ASA.
Bottom‐up effects of species diversity on the functioning and stability of food webs
Authors: Narwani Anita , Mazumder Asit 
Published: February 2012

Summary1. The importance of species diversity for the stability of populations, communities and ecosystem functions is a central question in ecology.2. Biodiversity experiments have shown that diversity can impact both the average and variability of stocks and rates at these levels of ecological organization in single trophic‐level ecosystems. Whether these impacts hold in food webs and across trophic levels is still unclear.3. We asked whether resource species diversity, community composition and consumer feeding selectivity in planktonic food webs impact the stability of resource or consumer populations, community biomass and ecosystem functions. We also tested the relative importance of resource diversity and community composition.4. We found that resource diversity negatively affected resource population stability, but had no effect on consumer population stability, regardless of the consumer’s feeding selectivity. Resource diversity had positive effects on most ecosystem functions and their stability, including primary production, resource biomass and particulate carbon, nitrogen and phosphorus concentrations.5. Community composition, however, generally explained more variance in population, community and ecosystem properties than species diversity per se. This result points to the importance of the outcomes of particular species interactions and individual species’ effect traits in determining food web properties and stability.6. Among the stabilizing mechanisms tested, an increase in the average resource community biomass with increasing resource diversity had the greatest positive impact on stability.7. Our results indicate that resource diversity and composition are generally important for the functioning and stability of whole food webs, but do not have straightforward impacts on consumer populations.
The Chronic Sleep Reduction Questionnaire (CSRQ): a cross‐cultural comparison and validation in Dutch and Australian adolescents
Authors: DEWALD JULIA F. , SHORT MICHELLE A. , GRADISAR MICHAEL , OORT FRANS J. , MEIJER ANNE MARIE 
Published: February 2012

SummaryAlthough adolescents often experience insufficient and/or poor sleep, sleep variables such as total sleep time do not account for individuals’ sleep need and sleep debt and may therefore be an inadequate representation of adolescents’ sleep problems and its daytime consequences. This problem can be overcome by using the Chronic Sleep Reduction Questionnaire (CSRQ), an assessment tool that measures symptoms of chronic sleep reduction and therefore accounting for sleep need and sleep debt. The present study aims at developing an English version of the CSRQ and assesses the reliability and validity of the Dutch and the English CSRQ version. The CSRQ was administered in large Dutch (n = 166, age = 15.2 ± 0.57 years, 28% male) and Australian (n = 236, age = 15.5 ± 0.99 years, 65% males) samples. Subjective sleep variables were measured with surveys and sleep diaries of five school nights. Additionally, sleep of the same five nights was monitored with actigraphy. Both CSRQ versions showed good psychometric properties concerning their reliability (Dutch: α = 0.85; English: α = 0.87) and validity as the same overall structure of the two CSRQ versions and significant correlations with subjective and objective sleep variables were found. School grades were related to chronic sleep reduction, whereas the relationship between grades and other sleep variables was weak or absent. These results highlight the idea that chronic sleep reduction may be a better indicator of adolescents’ insufficient and/or poor sleep than other sleep variables such as total sleep time.
Influences on medical students’ self‐regulated learning after test completion
Authors: Agrawal Sacha , Norman Geoffrey R , Eva Kevin W 
Published: February 2012

Medical Education 2012:46: 326–335Context The inadequacy of self‐assessment as a mechanism to guide performance improvements has placed greater emphasis on the value of testing as a pedagogic strategy. The mechanism whereby testing influences learning is incompletely understood. This study was performed to examine which aspects of a testing experience most influence self‐regulated learning behaviour among medical students.Methods Sixty‐seven medical students participated in a computer‐based, multiple‐choice test. Initially, participants were instructed to attempt only items for which they felt confident of their response. They were then asked to indicate their best responses to deferred items. Students were then given an opportunity to review the items, with correct responses indicated. Accuracy, the attempt/defer decision and the time taken to reach this decision were recorded, along with participants’ ratings of their confidence in each response and the time spent reviewing each item on completion of the test.Results Students correctly answered a larger proportion of attempted items than deferred items (71% versus 40%; p < 0.001), and indicated a higher mean confidence in responses to items they answered correctly compared with items they answered incorrectly (70 versus 46; p < 0.001). They spent longer reviewing items they had answered incorrectly than correctly (8.3 versus 4.0 seconds; p < 0.001), and paid particular attention to items for which the attempt/defer decision and accuracy were discordant (p < 0.01). The amount of time required to make a decision on whether or not to answer a test question was also related to reviewing time.Conclusions Medical students showed a robust ability to accurately and consciously self‐monitor their likelihood of success on multiple‐choice test items. By focusing their subsequent self‐regulated learning on areas in which performance and self‐monitoring judgements were misaligned, participants reinforced the importance of providing learners with opportunities to discover the limits of their ability and further elucidated the mechanism through which test‐enhanced learning might be derived.
Cultural similarities and differences in medical professionalism: a multi‐region study
Authors: Chandratilake Madawa , McAleer Sean , Gibson John 
Published: February 2012

Medical Education 2012: 46: 257–266Context  Over the last two decades, many medical educators have sought to define professionalism. Initial attempts to do so were focused on defining professionalism in a manner that allowed for universal agreement. This quest was later transformed into an effort to ‘understand professionalism’ as many researchers realised that professionalism is a social construct and is culture‐sensitive. The determination of cultural differences in the understanding of professionalism, however, has been subject to very little research, possibly because of the practical difficulties of doing so. In this multi‐region study, we illustrate the universal and culture‐specific aspects of medical professionalism as it is perceived by medical practitioners.Methods  Forty‐six professional attributes were identified by reviewing the literature. A total of 584 medical practitioners, representing the UK, Europe, North America and Asia, participated in a survey in which they indicated the importance of each of these attributes. We determined the ‘essentialness’ of each attribute in different geographic regions using the content validity index, supplemented with kappa statistics.Results  With acceptable levels of consensus, all regional groups identified 29 attributes as ‘essential’, thereby indicating the universality of these professional attributes, and six attributes as non‐essential. The essentialness of the rest varied by regional group.Conclusions  This study has helped to identify regional similarities and dissimilarities in understandings of professionalism, most of which can be explained by cultural differences in line with the theories of cultural dimensions and cultural value. However, certain dissonances among regions may well be attributable to socio‐economic factors. Some of the responses appear to be counter‐cultural and demonstrate practitioners’ keenness to overcome cultural barriers in order to provide better patient care.
Reliability estimates: behavioural stations and questionnaires in medical school admissions
Authors: Gafni Naomi , Moshinsky Avital , Eisenberg Orit , Zeigler David , Ziv Amitai 
Published: February 2012

Medical Education 2012: 46: 277–288Context  Assessment centres used in evaluating the non‐cognitive attributes of medical school candidates must generate scores that reflect as accurate a measurement as possible of these attributes. Thus far, reliability coefficients for such centres have been based on limited samples and individual administrations, without reference to the error of variance that may result from retesting, or from the existence of multiple centres designed to measure the same attributes.Methods  The National Institute for Testing and Evaluation in Israel has developed and administered two assessment centres: MOR is used by two medical schools and one dental school, and MIRKAM by another medical school. Each centre comprises eight or nine behavioural stations, a standardised biographical questionnaire, and a judgement and decision‐making questionnaire. We calculated generalisability coefficients for each centre’s eight or nine stations by year, composite reliability coefficients for the overall assessment centres, test–retest correlation coefficients for repeaters, and a correlation coefficient between the centres.Results  Between 2006 and 2009, 2662 and 2023 examinees participated in MOR and MIRKAM, respectively; 1479 of these participated in both. The average generalisability coefficients for the stations were 0.69 for MOR and 0.67 for MIRKAM. The composite reliability coefficients for the full centres (behavioural stations plus questionnaires) were 0.79 and 0.76 for MOR and MIRKAM, respectively. The correlations for repeaters, corrected for restriction of range, were 0.59 and 0.43 for MOR and MIRKAM stations, respectively, and 0.72 and 0.65 for the full MOR and MIRKAM assessments, respectively. The correlation between scores on the MOR and MIRKAM stations was 0.56 (0.75 for the overall score).Discussion  The minimal reliability desirable for high‐stakes decision making (0.80) was obtained only for 14 or 15 stations with questionnaires. Nevertheless, the values obtained are considerably higher than reliability coefficients for single interviews. The questionnaires contribute significantly to the accuracy of the measurement. These reliability measures constitute an upper threshold for measures of validity.
LUCAS: a theoretically informed instrument to assess clinical communication in objective structured clinical examinations
Authors: Huntley Christopher D , Salmon Peter , Fisher Peter L , Fletcher Ian , Young Bridget 
Published: February 2012

Medical Education 2012: 46: 267–276Objectives  We reviewed papers describing the development of instruments for assessing clinical communication in undergraduate medical students. The instruments had important limitations: most lacked a theoretical basis, and their psychometric properties were often poor or inadequately investigated and reported. We therefore describe the development of a new instrument, the Liverpool Undergraduate Communication Assessment Scale (LUCAS), which is intended to overcome some of these limitations. We designed LUCAS to reflect the theory that communication is contextually dependent, inherently creative and cannot be fully described within a conceptual framework of discrete skills.Methods  We investigated the preliminary psychometric properties of LUCAS in two studies. To assess construct and external validity, we examined correlations between examiners’ LUCAS ratings and simulated patients’ ratings of their relationships with students in Year 1 formative (n = 384) and summative (n = 347) objective structured clinical examination (OSCE) samples. Item–total correlations and item difficulty analyses were also performed. The dimensionality of LUCAS was examined by confirmatory factor analysis. We also assessed inter‐rater reliability; four raters used LUCAS to rate 40 video‐recorded encounters between Year 1 students and simulated patients.Results  Simulated patient ratings correlated with examiner ratings across two OSCE datasets. All items correlated with the total score. Item difficulty showed LUCAS was able to discriminate between student performances. LUCAS had a two‐dimensional factor structure: we labelled Factor 1 creative communication and Factor 2 procedural communication. The intraclass correlation coefficient was 0.73 (95% confidence interval 0.54–0.85), indicating acceptable reliability.Conclusions  We designed LUCAS to move the primary focus of examiners away from an assessment of students’ enactment of behavioural skills to a judgement of how well students’ communication met patients’ needs. LUCAS demonstrated adequate reliability and validity. The instrument can be administered easily and efficiently and is therefore suitable for use in medical school examinations.
Prevalence of abnormal cases in an image bank affects the learning of radiograph interpretation
Authors: Pusic Martin V , Andrews John S , Kessler David O , Teng David C , Pecaric Martin R , Ruzal‐Shapiro Carrie , Boutis Kathy 
Published: February 2012

Medical Education 2012: 46: 289–298Objectives  Using a large image bank, we systematically examined how the use of different ratios of abnormal to normal cases affects trainee learning.Methods  This was a prospective, double‐blind, randomised, three‐arm education trial conducted in six academic training programmes for emergency medicine and paediatric residents in post‐licensure years 2–5. We developed a paediatric ankle trauma radiograph case bank. From this bank, we constructed three different 50‐case training sets, which varied in their proportions of abnormal cases (30%, 50%, 70%). Levels of difficulty and diagnoses were similar across sets. We randomly assigned residents to complete one of the training sets. Users classified each case as normal or abnormal, specifying the locations of any abnormalities. They received immediate feedback. All participants completed the same 20‐case post‐test in which 40% of cases were abnormal. We determined participant sensitivity, specificity, likelihood ratio and signal detection parameters.Results  A total of 100 residents completed the study. The groups did not differ in accuracy on the post‐test (p = 0.20). However, they showed considerable variation in their sensitivity–specificity trade‐off. The group that received a training set with a high proportion of abnormal cases achieved the best sensitivity (0.69, standard deviation [SD] = 0.24), whereas the groups that received training sets with medium and low proportions of abnormal cases demonstrated sensitivities of 0.63 (SD = 0.21) and 0.51 (SD = 0.24), respectively (p < 0.01). Conversely, the group with a low proportion of abnormal cases demonstrated the best specificity (0.83, SD = 0.10) compared with the groups with medium (0.70, SD = 0.15) and high (0.66, SD = 0.17) proportions of abnormal cases (p < 0.001). The group with a low proportion of abnormal cases had the highest false negative rate and missed fractures one‐third more often than the groups that trained on higher proportions of abnormal cases.Conclusions  Manipulating the ratio of abnormal to normal cases in learning banks can have important educational implications.
Activists in the Making: Urban Movements, Political Processes and the Creation of Political Subjects
Authors: Rutland Ted 
Published: February 2012

AbstractA constant and largely unquestioned characteristic of contemporary studies of urban movements is their conception of the activist ‘subject’— the reflective agent or ‘doer’ who participates in, and shapes, urban movements. Whereas it has become increasingly common in other scholarly research to regard the subject as a contingent, context‐specific outcome or creation, studies of urban movements have not been swayed. The latter, even as they proceed to conceptualize more and more of the urban scene in terms of malleable ‘processes’ rather than inert ‘structures’, have continued to regard the makeup of the activist subject as universal and invariable. This article, in contrast, proposes and explores a different approach. Through a review of the recent urban movements literature, a focused consideration of potentially complementary literatures, and a demonstrative case study, this article aims to show that it is possible and indeed worthwhile to examine how political subjects are contingently remade both prior to, and through, their active participation in contentious urban politics. The remaking of political subjects, it concludes, is often central to the formation and achievements of urban movements. Devoting increased attention to this process — alongside other, already‐recognized political processes — could, therefore, promote a richer, more complex understanding of activism and the ever‐changing city.RésuméLes études contemporaines sur les mouvements urbains partagent une caractéristique rarement remise en cause, à savoir leur conception du ‘sujet’ militant, individu agissant ou agent réfléchi qui participe à ces mouvements et les façonne. Alors que les autres domaines de recherches considèrent de plus en plus souvent le sujet comme un produit ou une création contingente propre au contexte, les études sur les mouvements urbains ont échappéà cette tendance. Même si elles se sont mises à conceptualiser la scène urbaine en termes de ‘processus’ malléables plus largement qu'en termes de ‘structures’ inertes, elles ont continuéà considérer le profil du sujet militant comme universel et invariable. Une approche différente est proposée et analysée ici. En examinant la littérature récente sur les mouvements urbains, ainsi que les publications susceptibles de les compléter et une étude de cas probante, cet article montre qu'il est possible, et assurément utile, d'étudier comment les sujets politiques sont recomposés en fonction des situations, à la fois avant et grâce à leur participation active à une politique urbaine controversée. En conclusion, la recomposition des sujets politiques est souvent essentielle à la formation et aux réussites des mouvements urbains. Accorder une attention accrue à ce processus — parallèlement à d'autres processus politiques déjà reconnus — pourrait donc favoriser une conception plus riche et plus complexe de l'activisme et de la ville en constante évolution.