Ageing effects around the glass and melting transitions in poly(dimethylsiloxane) visualized by resistance measurements

The process of ageing in rubbers requires monitoring over long periods (days to years). To do so in non-conducting rubbers, small amounts of carbon-black particles were dispersed in a fractal network through the rubber matrix, to make the rubber conducting without modifying its properties. Continuous monitoring of the resistance reveals the structural changes around the glass and melting transitions and especially details about the hysteresis and ageing processes. We illustrate the method for the semicrystalline polymer poly(dimethylsiloxane) (PDMS).Comment: 4 pages, 4 figure

Research in medical education: pratical impact on medical training and future challenges

Medical education research has changed over the years from merely descriptive studies towards justification or curriculum comparison studies and, nowadays, towards a slow introduction of more clarification studies. In clarification studies quantitative and qualitative methods are used to explain why or how educational interventions work or do not work. This shift is described in this paper. In addition, it is explained how research into workplace learning and assessment has impacted developments in educational practice. Finally, it is argued that the participation of teachers within the medical domain in conducting and disseminating research should be cherished, because they play a crucial role in ensuring that medical education research is applied in educational practice

A new framework for designing programmes of assessment

Research on assessment in medical education has strongly focused on individual measurement instruments and their psychometric quality. Without detracting from the value of this research, such an approach is not sufficient to high quality assessment of competence as a whole. A programmatic approach is advocated which presupposes criteria for designing comprehensive assessment programmes and for assuring their quality. The paucity of research with relevance to programmatic assessment, and especially its development, prompted us to embark on a research project to develop design principles for programmes of assessment. We conducted focus group interviews to explore the experiences and views of nine assessment experts concerning good practices and new ideas about theoretical and practical issues in programmes of assessment. The discussion was analysed, mapping all aspects relevant for design onto a framework, which was iteratively adjusted to fit the data until saturation was reached. The overarching framework for designing programmes of assessment consists of six assessment programme dimensions: Goals, Programme in Action, Support, Documenting, Improving and Accounting. The model described in this paper can help to frame programmes of assessment; it not only provides a common language, but also a comprehensive picture of the dimensions to be covered when formulating design principles. It helps identifying areas concerning assessment in which ample research and development has been done. But, more importantly, it also helps to detect underserved areas. A guiding principle in design of assessment programmes is fitness for purpose. High quality assessment can only be defined in terms of its goals

Driving lesson or driving test?:A metaphor to help faculty separate feedback from assessment

Although there is consensus in the medical education world that feedback is an important and effective tool to support experiential workplace-based learning, learners tend to avoid the feedback associated with direct observation because they perceive it as a high-stakes evaluation with significant consequences for their future. The perceived dominance of the summative assessment paradigm throughout medical education reduces learners’ willingness to seek feedback, and encourages supervisors to mix up feedback with provision of ‘objective’ grades or pass/fail marks. This eye-opener article argues that the provision and reception of effective feedback by clinical supervisors and their learners is dependent on both parties’ awareness of the important distinction between feedback used in coaching towards growth and development (assessment for learning) and reaching a high-stakes judgement on the learner’s competence and fitness for practice (assessment of learning). Using driving lessons and the driving test as a metaphor for feedback and assessment helps supervisors and learners to understand this crucial difference and to act upon it. It is the supervisor’s responsibility to ensure that supervisor and learner achieve a clear mutual understanding of the purpose of each interaction (i.e. feedback or assessment). To allow supervisors to use the driving lesson—driving test metaphor for this purpose in their interactions with learners, it should be included in faculty development initiatives, along with a discussion of the key importance of separating feedback from assessment, to promote a feedback culture of growth and support programmatic assessment of competence

Low-loss, low-confinement GaAs-AlGaAs DQW laser diode with optical trap layer for high-power operation

A low-confinement asymmetric GaAs-AlGaAs double-quantum-well molecular-beam-epitaxy grown laser diode structure with optical trap layer is characterized, The value of the internal absorption coefficient is as low as 1.4 cm-1, while keeping the series resistance at values comparable cm with symmetrical quantum-well gradient index structures in the same material system. Uncoated devices show COD values of 35 mW/µm. If coated, this should scale to about 90 mW/µm. The threshold current density is about 1000 A/cm2 for 2-mm-long devices and a considerable part of it is probably due to recombination in the optical trap layer. Fundamental mode operation is limited to 120-180 mW for 6.5-µm-wide ridge waveguide uncoated devices and to 200-300 mW for 13.5-µm-wide ones, because of thermal waveguiding effects. These values are measured under pulsed conditions, 10 µs/l m

The role of deliberate practice in the acquisition of clinical skills

<p>Abstract</p> <p>Background</p> <p>The role of deliberate practice in medical students' development from novice to expert was examined for preclinical skill training.</p> <p>Methods</p> <p>Students in years 1-3 completed 34 Likert type items, adapted from a questionnaire about the use of deliberate practice in cognitive learning. Exploratory factor analysis and reliability analysis were used to validate the questionnaire. Analysis of variance examined differences between years and regression analysis the relationship between deliberate practice and skill test results.</p> <p>Results</p> <p>875 students participated (90%). Factor analysis yielded four factors: planning, concentration/dedication, repetition/revision, study style/self reflection. Student scores on 'Planning' increased over time, score on sub-scale 'repetition/revision' decreased. Student results on the clinical skill test correlated positively with scores on subscales 'planning' and 'concentration/dedication' in years 1 and 3, and with scores on subscale 'repetition/revision' in year 1.</p> <p>Conclusions</p> <p>The positive effects on test results suggest that the role of deliberate practice in medical education merits further study. The cross-sectional design is a limitation, the large representative sample a strength of the study. The vanishing effect of repetition/revision may be attributable to inadequate feedback. Deliberate practice advocates sustained practice to address weaknesses, identified by (self-)assessment and stimulated by feedback. Further studies should use a longitudinal prospective design and extend the scope to expertise development during residency and beyond.</p

Sus, quo vadis? (Varken, waar gaat gij heen?); Ruimtelijke vestigingsprincipes voor varkensbedrijven

Vestigingsprincipes voor varkensbedrijven zijn onderzocht met inachtname van hun ge-volgen voor de milieubelasting, diergezondheid, dierwelzijn en de bedrijfsrentabiliteit. Het vrije vestigingsprincipe heeft zijn grenzen bereikt. De overheid moet het tot stand komen van professionele meer duurzame relaties tussen ketenpartijen stimuleren en randvoor-waarden stellen aan vestigingsprincipes

A model of the pre-assessment learning effects of summative assessment in medical education

It has become axiomatic that assessment impacts powerfully on student learning. However, surprisingly little research has been published emanating from authentic higher education settings about the nature and mechanism of the pre-assessment learning effects of summative assessment. Less still emanates from health sciences education settings. This study explored the pre-assessment learning effects of summative assessment in theoretical modules by exploring the variables at play in a multifaceted assessment system and the relationships between them. Using a grounded theory strategy, in-depth interviews were conducted with individual medical students and analyzed qualitatively. Respondents’ learning was influenced by task demands and system design. Assessment impacted on respondents’ cognitive processing activities and metacognitive regulation activities. Individually, our findings confirm findings from other studies in disparate non-medical settings and identify some new factors at play in this setting. Taken together, findings from this study provide, for the first time, some insight into how a whole assessment system influences student learning over time in a medical education setting. The findings from this authentic and complex setting paint a nuanced picture of how intricate and multifaceted interactions between various factors in an assessment system interact to influence student learning. A model linking the sources, mechanism and consequences of the pre-assessment learning effects of summative assessment is proposed that could help enhance the use of summative assessment as a tool to augment learning