2,391 research outputs found
Molecular shape as a means to control the incidence of the nanostructured twist bend phase
Liquid crystalline phases with a spontaneous twist-bend modulation are most commonly observed for dimers and bimesogens with nonamethylene spacers. In order to redress this balance we devised a simple chemical intermediate that can be used to prepare unsymmetrical bimesogens; as a proof of concept we prepared and studied eleven novel materials with all found to exhibit the twist-bend phase and exhibit a linear relationship between TN-I and TTB-N. A computational study of the conformational landscape reveals the octamethyleneoxy spacer to have a broader distribution of bend-angles than the nonamethylene equivalent, leading to reductions in the thermal stability of the TB phase. This result indicates that a tight distribution of bend-angles should stabilise the TB phase and lead to direct TB-Iso phase transitions, and conversely a broader distribution should destabilise the TB phase which may allow new states of matter that are occluded by the incidence of this phase to be revealed
Categorisation of continuous risk factors in epidemiological publications: a survey of current practice
BACKGROUND: Reports of observational epidemiological studies often categorise (group) continuous risk factor (exposure) variables. However, there has been little systematic assessment of how categorisation is practiced or reported in the literature and no extended guidelines for the practice have been identified. Thus, we assessed the nature of such practice in the epidemiological literature. Two months (December 2007 and January 2008) of five epidemiological and five general medical journals were reviewed. All articles that examined the relationship between continuous risk factors and health outcomes were surveyed using a standard proforma, with the focus on the primary risk factor. Using the survey results we provide illustrative examples and, combined with ideas from the broader literature and from experience, we offer guidelines for good practice. RESULTS: Of the 254 articles reviewed, 58 were included in our survey. Categorisation occurred in 50 (86%) of them. Of those, 42% also analysed the variable continuously and 24% considered alternative groupings. Most (78%) used 3 to 5 groups. No articles relied solely on dichotomisation, although it did feature prominently in 3 articles. The choice of group boundaries varied: 34% used quantiles, 18% equally spaced categories, 12% external criteria, 34% other approaches and 2% did not describe the approach used. Categorical risk estimates were most commonly (66%) presented as pairwise comparisons to a reference group, usually the highest or lowest (79%). Reporting of categorical analysis was mostly in tables; only 20% in figures. CONCLUSIONS: Categorical analyses of continuous risk factors are common. Accordingly, we provide recommendations for good practice. Key issues include pre-defining appropriate choice of groupings and analysis strategies, clear presentation of grouped findings in tables and figures, and drawing valid conclusions from categorical analyses, avoiding injudicious use of multiple alternative analyses
Hot hands, cold feet? Investigating effects of interacting constraints on place kicking performance at the 2015 Rugby Union World Cup
Place kicks in Rugby Union present valuable opportunities to score points outside the spatiotemporal dynamics of open play but are executed under varying performance constraints. We analysed effects of specific task constraints and relevant contextual factors on place kick performance in the 2015 Rugby Union World Cup. Data were collected from television broadcasts for each place kick. In addition to kick outcomes, contextual factors, including time of the kick in the match, score margin at the time of the kick, and outcome of the kicker’s previous kick, were recorded. Effects of spatial task constraints were analysed for each kick, using distance (m) and angle (°) of the kick to the goalposts. A binomial logistic regression model revealed that distance from, and angle to, the goalposts were significant predictors of place kick outcome. Furthermore, the success percentage of kickers who missed their previous kick was 7% lower than those who scored their previous kick. Place kick success percentage in the 10 minutes before half-time was 8% lower than the mean tournament success percentage, which was 75% (95% CI 71% to 78%). The highest kick success percentage was recorded when scores were level (83%; 95% CI 72% to 91%). Our data highlighted how subtle changes in task constraints and contextual factors can influence performance outcomes in elite performers in international competition. Fluctuations in place kick success suggested that individual constraints, such as thoughts, emotions, and fatigue, induced during competition, could interact with perceptions to influence emergent performance behaviours
Focal plant observations as a standardised method for pollinator monitoring: opportunities and limitations for mass participation citizen science
Background: Recently there has been increasing focus on monitoring pollinating insects, due to concerns about their declines, and interest in the role of volunteers in monitoring pollinators, particularly bumblebees, via citizen science.
Methodology/Principal Findings: The Big Bumblebee Discovery was a one-year citizen science project run by a partnership of EDF Energy, the British Science Association and the Centre for Ecology & Hydrology which sought to assess the influence of the landscape at multiple scales on the diversity and abundance of bumblebees. Timed counts of bumblebees (
Bombus spp.; identified to six colour groups) visiting focal plants of lavender (Lavendula spp.) were carried out by about 13 000 primary school children (7 – 11 years old) from over 400 schools across the UK. 3948 reports were received totalling 26 868 bumblebees. We found that while the wider landscape type had no significant effect on reported bumblebee abundance, the local proximity to flowers had a significant effect (fewer bumblebees where other flowers were reported to be > 5m away from the focal plant). However, the rate of mis-identifcation,
revealed by photographs uploaded by participants and a photo-based quiz, was high.
Conclusions/Significance: Our citizen science results support recent research on the importance of local floral resources on pollinator abundance. Timed counts of insects visiting a lure plant is potentially an effective approach for standardised pollinator monitoring, engaging a large number of participants with a simple protocol. However, the relatively high rate of mis-identifications (compared to reports from previous pollinator citizen science projects) highlights the importance of investing in resources to train volunteers. Also, to be a scientifically valid method for enquiry, citizen science data needs to be sufficiently high quality, so receiving supporting evidence (such as photographs) would allow this to be tested and for records to be verified
Global competencies in family medicine
Introduction:This project was devised to provide a global snapshot of required national competencies in Family Medicine, and is the result of an international collaboration of the International Fellowship of Primary Care Research Networks (IFPCRN). The Research team, which devised the questionnaire and original list of competencies, was drawn from around 30 countries and 15 countries responded to the questionnaire and contributed national data. These countries however represented close to two thirds of our global population and included Low, Middle and High Income countries (based on World Bank Purchasing price Parity (PPP) 2005) as well Parity (PPP) 2005) as well as representing a good cross section of climatological, socio economic and geographical situations.
Aims and Objectives: To compile a list of competencies required of global family doctors, via global consultation, and use them in the form of a questionnaire to survey national family medicine representatives to ascertain if family doctors are required to be competent in these disciplines. The Objective is to provide a ‘global snapshot’ of competencies and trends in family medicine
Materials and Methods: A representative list of family medicine competencies was compiled by an International Fellowship of Primary Care Research Networks (IFPCRN) group, from 30 countries over a 3-month period, commencing June 2009.
A list of 57 expanded items, and 44 core items was then compiled and formed the basis of a questionnaire, with provision for adding additional competencies that did not appear in the list of 57. This was broadcast by list server to the IFPCRN email group.
Results: 15 Family medicine/ primary care representatives completed the survey on behalf of their nation (or region in the case of West Africa). Results showed a trend toward a globally standard curriculum but still much variation in competencies taught
Delivering quality along with quantity: the challenge of teaching a large and heterogeneous engineering class
The challenges faced by a lecturer teaching large multidisciplinary engineering classes are identified. These are principally related to the size of the class, the extensive mathematical knowledge that is considered as prerequisite, as well as the heterogeneity of the class due to the diversity of students’ academic background and interests. In order to improve students’ engagement and retention in class, active learning techniques are employed and their impact on the performance of the class is captured through a questionnaire designed for this purpose. The statistics demonstrate that good teaching facilities and a well-prepared lecturer do not suffice for maximising students’ satisfaction, attention and retention. In order to engage the students in a large class setting, it is important to involve them in the lecture process. The employed active learning methods comprising quizzes, in class demonstration and muddiest-point cards induce a remarkably positive impact at almost no additional teaching resources
Issues in the reporting of epidemiological studies: a survey of recent practice.
OBJECTIVES: To review current practice in the analysis and reporting of epidemiological research and to identify limitations. DESIGN: Examination of articles published in January 2001 that investigated associations between risk factors/exposure variables and disease events/measures in individuals. SETTING: Eligible English language journals including all major epidemiological journals, all major general medical journals, and the two leading journals in cardiovascular disease and cancer. MAIN OUTCOME MEASURE: Each article was evaluated with a standard proforma. RESULTS: We found 73 articles in observational epidemiology; most were either cohort or case-control studies. Most studies looked at cancer and cardiovascular disease, even after we excluded specialty journals. Quantitative exposure variables predominated, which were mostly analysed as ordered categories but with little consistency or explanation regarding choice of categories. Sample selection, participant refusal, and data quality received insufficient attention in many articles. Statistical analyses commonly used odds ratios (38 articles) and hazard/rate ratios (23), with some inconsistent use of terminology. Confidence intervals were reported in most studies (68), though use of P values was less common (38). Few articles explained their choice of confounding variables; many performed subgroup analyses claiming an effect modifier, though interaction tests were rare. Several investigated multiple associations between exposure and outcome, increasing the likelihood of false positive claims. There was evidence of publication bias. CONCLUSIONS: This survey raises concerns regarding inadequacies in the analysis and reporting of epidemiological publications in mainstream journals
A strategic framework to support the implementation of citizen science for environmental monitoring. Final report to SEPA
In this report we provide a decision framework that can be used to guide whether and when to use a
citizen science approach for environmental monitoring. Before using the decision framework we
recommend that five precursors to a citizen science approach are considered
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