Correspondence between alternate measures of maladaptive exercise, and their associations with disordered eating symptomatology

Aims: The study sought to contribute to the measurement of maladaptive exercise by examining the psychometric properties of a variety of instruments and classification algorithms. The primary aim was to identify the items or scales necessary and sufficient to quantify the construct. A secondary aim was to comment on the construct validity of these measures by examining their relationships with disordered eating symptomatology. Methods: Questionnaire booklets comprising the Exercise Dependence Scale, the Obligatory Exercise Questionnaire, the Frequency, Intensity, Time Index, and the Eating Attitudes Test were distributed to women attending health and fitness centres. Self-reported age, height, current and desired weight, and length of time as a regular exerciser were also sought. Data were obtained from 302 regular exercisers. Results: While there were statistically significant associations among the measures, no two operationalised maladaptive exercise in the same manner. The Frequency-Intensity-Time Index (FIT) was found to be particularly poor. While variation in the size of relationships between maladaptive exercise and disordered eating was noted, all measures were strongly correlated with the exception of FIT, which demonstrated a modest correlation. Conclusions: Different conceptualisations of maladaptive exercise have led to alternative operational definitions, resulting in its classification being instrument dependent. Further exploration using samples with differing characteristics (e.g., high/low probability of dependence) may allow more specific recommendations to be made about the optimal measurement of maladaptive exercise. Further, the question of whether maladaptive exercise is more likely a cause or consequence of eating disorders remains

Motivational and psychological correlates of bodybuilding dependence

Abstract Background and aims Exercise may become physically and psychologically maladaptive if taken to extremes. One example is the dependence reported by some individuals who engage in weight training. The current study explored potential psychological, motivational, emotional and behavioural concomitants of bodybuilding dependence, with a particular focus on motives for weight training. Using a path analysis paradigm, putative causal models sought to explain associations among key study variables. Methods A convenience sample of 101 men aged between 18 and 67 years was assembled from gymnasia in Adelaide, South Australia. Active weight trainers voluntarily completed a questionnaire that included measures of bodybuilding dependence (social dependency, training dependency, and mastery), anger, hostility and aggression, stress and motivations for weight training. Results Three motives for weight training were identified: mood control, physique anxiety and personal challenge. Of these, personal challenge and mood control were the most directly salient to dependence. Social dependency was particularly relevant to personal challenge, whereas training dependency was associated with both personal challenge and mood control. Mastery demonstrated a direct link with physique anxiety, thus reflecting a unique component of exercise dependence. Conclusions While it was not possible to determine causality with the available data, the joint roles of variables that influence, or are influenced by, bodybuilding dependence are identified. Results highlight unique motivations for bodybuilding and suggest that dependence could be a result of, and way of coping with, stress manifesting as aggression. A potential framework for future research is provided through the demonstration of plausible causal linkages among these variables

Conformational flexibility revealed by the crystal structure of a crenarchaeal RadA

Homologous recombinational repair is an essential mechanism for repair of double-strand breaks in DNA. Recombinases of the RecA-fold family play a crucial role in this process, forming filaments that utilize ATP to mediate their interactions with single- and double-stranded DNA. The recombinase molecules present in the archaea (RadA) and eukaryota (Rad51) are more closely related to each other than to their bacterial counterpart (RecA) and, as a result, RadA makes a suitable model for the eukaryotic system. The crystal structure of Sulfolobus solfataricus RadA has been solved to a resolution of 3.2 Å in the absence of nucleotide analogues or DNA, revealing a narrow filamentous assembly with three molecules per helical turn. As observed in other RecA-family recombinases, each RadA molecule in the filament is linked to its neighbour via interactions of a short β-strand with the neighbouring ATPase domain. However, despite apparent flexibility between domains, comparison with other structures indicates conservation of a number of key interactions that introduce rigidity to the system, allowing allosteric control of the filament by interaction with ATP. Additional analysis reveals that the interaction specificity of the five human Rad51 paralogues can be predicted using a simple model based on the RadA structure

Measurement properties of the Inventory of Cognitive Bias in Medicine (ICBM)

© 2008 Sladek et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Background Understanding how doctors think may inform both undergraduate and postgraduate medical education. Developing such an understanding requires valid and reliable measurement tools. We examined the measurement properties of the Inventory of Cognitive Bias in Medicine (ICBM), designed to tap this domain with specific reference to medicine, but with previously questionable measurement properties. Methods First year postgraduate entry medical students at Flinders University, and trainees (postgraduate doctors in any specialty) and consultants (N = 348) based at two teaching hospitals in Adelaide, Australia, completed the ICBM and a questionnaire measuring thinking styles (Rational Experiential Inventory). Results Questions with the lowest item-total correlation were deleted from the original 22 item ICBM, although the resultant 17 item scale only marginally improved internal consistency (Cronbach's α = 0.61 compared with 0.57). A factor analysis identified two scales, both achieving only α = 0.58. Construct validity was assessed by correlating Rational Experiential Inventory scores with the ICBM, with some positive correlations noted for students only, suggesting that those who are naïve to the knowledge base required to "successfully" respond to the ICBM may profit by a thinking style in tune with logical reasoning. Conclusion The ICBM failed to demonstrate adequate content validity, internal consistency and construct validity. It is unlikely that improvements can be achieved without considered attention to both the audience for which it is designed and its item content. The latter may need to involve both removal of some items deemed to measure multiple biases and the addition of new items in the attempt to survey the range of biases that may compromise medical decision making

Testing the DGP model with ESSENCE

We use the recent supernova data set from the ESSENCE collaboration combined with data from the Supernova Legacy Survey and nearby supernovae to test the DGP brane world model and its generalisations. Combination of this data with a flatness prior and the position of the peak of the CMB disfavours the DGP model slightly. Inclusion of the baryon acoustic peak from the Sloan Digital Sky Survey increase the tension of the DGP model with the data, although it is not clear how self consistent this procedure would be without a re-analysis of the survey data in the framework of the DGP cosmology. Generalisations of the DGP model are tested and constraints on relevant parameters obtained.Comment: Minor corrections, clarifications and references added. Published in JCA

Implementation science: a role for parallel dual processing models of reasoning?

BACKGROUND: A better theoretical base for understanding professional behaviour change is needed to support evidence-based changes in medical practice. Traditionally strategies to encourage changes in clinical practices have been guided empirically, without explicit consideration of underlying theoretical rationales for such strategies. This paper considers a theoretical framework for reasoning from within psychology for identifying individual differences in cognitive processing between doctors that could moderate the decision to incorporate new evidence into their clinical decision-making. DISCUSSION: Parallel dual processing models of reasoning posit two cognitive modes of information processing that are in constant operation as humans reason. One mode has been described as experiential, fast and heuristic; the other as rational, conscious and rule based. Within such models, the uptake of new research evidence can be represented by the latter mode; it is reflective, explicit and intentional. On the other hand, well practiced clinical judgments can be positioned in the experiential mode, being automatic, reflexive and swift. Research suggests that individual differences between people in both cognitive capacity (e.g., intelligence) and cognitive processing (e.g., thinking styles) influence how both reasoning modes interact. This being so, it is proposed that these same differences between doctors may moderate the uptake of new research evidence. Such dispositional characteristics have largely been ignored in research investigating effective strategies in implementing research evidence. Whilst medical decision-making occurs in a complex social environment with multiple influences and decision makers, it remains true that an individual doctor's judgment still retains a key position in terms of diagnostic and treatment decisions for individual patients. This paper argues therefore, that individual differences between doctors in terms of reasoning are important considerations in any discussion relating to changing clinical practice. SUMMARY: It is imperative that change strategies in healthcare consider relevant theoretical frameworks from other disciplines such as psychology. Generic dual processing models of reasoning are proposed as potentially useful in identifying factors within doctors that may moderate their individual uptake of evidence into clinical decision-making. Such factors can then inform strategies to change practice

Assessing mathematical problem solving using comparative judgement

There is an increasing demand from employers and universities for school leavers to be able to apply their mathematical knowledge to problem solving in varied and unfamiliar contexts. These aspects are however neglected in most examinations of mathematics and, consequentially, in classroom teaching. One barrier to the inclusion of mathematical problem solving in assessment is that the skills involved are difficult to define and assess objectively. We present two studies that test a method called comparative judgement (CJ) that might be well suited to assessing mathematical problem solving. CJ is an alternative to traditional scoring that is based on collective expert judgements of students’ work rather than item-by-item scoring schemes. In Study 1 we used CJ to assess traditional mathematics tests and found it performed validly and reliably. In Study 2 we used CJ to assess mathematical problem-solving tasks and again found it performed validly and reliably. We discuss the implications of the results for further research and the implications of CJ for the design of mathematical problem-solving tasks

Utilisation of an operative difficulty grading scale for laparoscopic cholecystectomy

Background A reliable system for grading operative difficulty of laparoscopic cholecystectomy would standardise description of findings and reporting of outcomes. The aim of this study was to validate a difficulty grading system (Nassar scale), testing its applicability and consistency in two large prospective datasets. Methods Patient and disease-related variables and 30-day outcomes were identified in two prospective cholecystectomy databases: the multi-centre prospective cohort of 8820 patients from the recent CholeS Study and the single-surgeon series containing 4089 patients. Operative data and patient outcomes were correlated with Nassar operative difficultly scale, using Kendall’s tau for dichotomous variables, or Jonckheere–Terpstra tests for continuous variables. A ROC curve analysis was performed, to quantify the predictive accuracy of the scale for each outcome, with continuous outcomes dichotomised, prior to analysis. Results A higher operative difficulty grade was consistently associated with worse outcomes for the patients in both the reference and CholeS cohorts. The median length of stay increased from 0 to 4 days, and the 30-day complication rate from 7.6 to 24.4% as the difficulty grade increased from 1 to 4/5 (both p < 0.001). In the CholeS cohort, a higher difficulty grade was found to be most strongly associated with conversion to open and 30-day mortality (AUROC = 0.903, 0.822, respectively). On multivariable analysis, the Nassar operative difficultly scale was found to be a significant independent predictor of operative duration, conversion to open surgery, 30-day complications and 30-day reintervention (all p < 0.001). Conclusion We have shown that an operative difficulty scale can standardise the description of operative findings by multiple grades of surgeons to facilitate audit, training assessment and research. It provides a tool for reporting operative findings, disease severity and technical difficulty and can be utilised in future research to reliably compare outcomes according to case mix and intra-operative difficulty

The biogeochemical impact of glacial meltwater from Southwest Greenland

Biogeochemical cycling in high-latitude regions has a disproportionate impact on global nutrient budgets. Here, we introduce a holistic, multi-disciplinary framework for elucidating the influence of glacial meltwaters, shelf currents, and biological production on biogeochemical cycling in high-latitude continental margins, with a focus on the silica cycle. Our findings highlight the impact of significant glacial discharge on nutrient supply to shelf and slope waters, as well as surface and benthic production in these regions, over a range of timescales from days to thousands of years. Whilst biological uptake in fjords and strong diatom activity in coastal waters maintains low dissolved silicon concentrations in surface waters, we find important but spatially heterogeneous additions of particulates into the system, which are transported rapidly away from the shore. We expect the glacially-derived particles – together with biogenic silica tests – to be cycled rapidly through shallow sediments, resulting in a strong benthic flux of dissolved silicon. Entrainment of this benthic silicon into boundary currents may supply an important source of this key nutrient into the Labrador Sea, and is also likely to recirculate back into the deep fjords inshore. This study illustrates how geochemical and oceanographic analyses can be used together to probe further into modern nutrient cycling in this region, as well as the palaeoclimatological approaches to investigating changes in glacial meltwater discharge through time, especially during periods of rapid climatic change in the Late Quaternary