Despite myriad attempts over the years to design curricula with logical ordering and connections, concerns persist that students view science as a body of prescribed information to memorize. In this ...essay, we argue that attempts to build coherence into the curriculum reflect fundamental and enduring misconceptions about the nature of coherence itself. Using examples of prominent curriculum projects over the past decade, we argue that premeditated coherence, the kind of coherence that is planned and designed for students, may inhibit students’ learning to seek coherence for themselves. We conclude with an approach to curriculum and assessment that emphasizes students’ epistemic agency in seeking coherence.
Ageing or obsolescence describes the process of declining use of a particular publication over time and can affect the results of a citation analyses as the length of citation window can change ...rankings. Obsolescence may not only vary across fields but also across subfields or sub-disciplines. The aim of this study is to determine the sub-disciplinary differences of obsolescence on a larger scale allowing for differences over time as well. The study presents the results of an analysis of 82,759 references across 53 healthcare and health policy topics. The references in this study are extracted from systematic reviews published from 2012 to 2016. The analyses of obsolescence include median citation age and mean citation age. This study finds that the median citation age and the mean citation age differ considerably across groups. For the latter indicator, an analysis of the confidence intervals confirms these differences. Using the subfield categorisation from Cochrane review groups, we found larger differences across subfields than in the citing half-lives published by Journal Citation Reports. Obsolescence is important to consider when setting the length of the citation windows. This study emphasises the vast differences across health sciences subfields. The length of the citation period is thus highly important for the results of a bibliometric evaluation or study covering fields with very varying obsolescence rates.
Medline/PubMed is often first choice for health science researchers when doing literature searches. However, Medline/PubMed does not cover the health science research literature equally well across ...specialties. Embase is often considered an important supplement to Medline/PubMed in health sciences. The present study analyzes the coverage of Embase as a supplement to PubMed, and the aim of the study is to investigate if searching Embase can compensate for low PubMed retrieval.
The population in this study is all the included studies in all Cochrane reviews from 2012 to 2016 across the 53 Cochrane groups. The analyses were performed using two units of analysis (study and publication). We are examining the coverage in Embase of publications and studies not covered by PubMed (25,119 publications and 9,420 studies).
The results showed that using Embase as a supplement to PubMed resulted in a coverage of 66,994 publications out of 86,167 and a coverage rate of 77.7, 95% CI 75.05, 80.45 of all the included publications. Embase combined with PubMed covered 48,326 out of 54,901 studies and thus had a coverage rate of 88.0%, 95% CI 86.2, 89.9 of studies. The results also showed that supplementing PubMed with Embase increased coverage of included publications by 6.8 percentage points, and the coverage of studies increased by 5.5 percentage points. Substantial differences were found across and within review groups over time.
The included publications and studies in some groups are covered considerably better by supplementing with Embase, whereas in other groups, the difference in coverage is negligible. However, due to the variation over time, one should be careful predicting the benefit from supplementing PubMed with Embase to retrieve relevant publications to include in a review.
PubMed is one of the most commonly used search tools in biomedical and life sciences. Existing studies of database coverage generally conclude that searching PubMed may not be sufficient although ...some find that the contributions from other databases are modest at best. However, generalizability of the studies of the coverage of PubMed is typically restricted. The objective of this study is to analyze the coverage of PubMed across specialties and over time.
We use the more than 50,000 included studies in all Cochrane reviews published from 2012 to 2016 as our population and examine if the studies and resulting publications can be identified in PubMed.
The results show that PubMed has a coverage of 70.9, 95% confidence interval (CI) (68.40, 73.30) of all the included publications and 82.8%, 95% CI (80.9, 84.7) of the included studies. There are huge differences in coverage across and within specialties. In addition, coverage varies within groups over time.
Databases used for searching topics within the groups with highly varying or low coverage should be chosen with care as PubMed may have a relatively low coverage.
•This study presents the results of an analysis of more than 85,000 publications from the 53 Cochrane groups.•PubMed covers more than 80 percent of all studies and 71 percent of publications included in Cochrane reviews.•Coverage varies across specialties and within specialties over time.
Tungsten-based materials are among the main candidate plasma-facing materials for future fusion reactors where extreme conditions of thermomechanical stresses, radiation, and energetic particles must ...be withstood. Here a hybrid X-pinch platform combined with a pulsed power machine was used to study damage mechanisms in 90W–4Cu–6Ni tungsten heavy alloy as a result of exposure to high energy density plasma, X-ray radiation, and the resulting thermal shock. It was found that the plasma-facing surface of the material undergoes severe melting and ablation with the extent of ablation being higher in the Cu–Ni phase than the W particles. Rapid melting and solidification transform the W particles into fine dendrite morphologies embedded in the Cu–Ni solid solution. Cracking was also observed in the subsurface layers at the interfaces between the W particles and the Cu-rich phase of the Cu–Ni matrix. X-ray radiation, on the other hand, cause slight melting on the surface without significant ablation and no cracking.
Fragmented or multiple publishing is generally considered negative, as authors may inflate their number of articles through duplicate publications and salami publications. However, there are valid ...and defensible arguments for a single research study generating multiple publications. The existing literature confirm the existence of fragmented publishing; however, the extent of the phenomenon is questioned. The present study is a large-scale analysis within the health sciences of more than 50,000 studies and the resulting publications. The data allows us to analyze differences across subdisciplines as well as over time. The results show that the majority of the fragmented publications are journal articles. This study also shows that the extent of fragmented publishing is tied to subdisciplines. Increased as well as decreased fragmented publishing are found when we compare across the subdisciplines as the development is tied to subdisciplines. The implications are discussed.
Research on student epistemologies in introductory courses has highlighted the importance of understanding physics as "a refinement of everyday thinking" A. Einstein, J. Franklin Inst. 221, 349 ...(1936). That view is difficult to sustain in quantum mechanics, for students as for physicists. How might students manage the transition? In this article, we present a case study of a graduate student's approaches and reflections on learning over two semesters of quantum mechanics, based on a series of nine interviews. We recount his explicit grappling with the shift in epistemology from classical to quantum, and we argue that his success in learning largely involved his framing mathematics as expressing physical meaning. At the same time, we show he was not entirely stable in these framings, shifting away from them in particular during his study of scattering. The case speaks to literature on students' epistemologies, with respect to the roles of everyday thinking and mathematics. We discuss what this case suggests for further research, with possible implications for instruction.
Legionnaires' disease is under-diagnosed because of inconsistent use of diagnostic tests and uncertainty about whom to test. We assessed the increase in case detection following large-scale ...introduction of routine PCR testing of respiratory specimens in New Zealand.
LegiNZ was a national surveillance study done over 1-year in which active case-finding was used to maximise the identification of cases of Legionnaires' disease in hospitals. Respiratory specimens from patients of any age with pneumonia, who could provide an eligible lower respiratory specimen, admitted to one of 20 participating hospitals, covering a catchment area of 96% of New Zealand's population, were routinely tested for legionella by PCR. Additional cases of Legionnaires' disease in hospital were identified through mandatory notification.
Between May 21, 2015, and May 20, 2016, 5622 eligible specimens from 4862 patients were tested by PCR. From these, 197 cases of Legionnaires' disease were detected. An additional 41 cases were identified from notification data, giving 238 cases requiring hospitalisation. The overall incidence of Legionnaires' disease cases in hospital in the study area was 5·4 per 100 000 people per year, and Legionella longbeachae was the predominant cause, found in 150 (63%) of 238 cases.
The rate of notified disease during the study period was three-times the average over the preceding 3 years. Active case-finding through systematic PCR testing better clarified the regional epidemiology of Legionnaires' disease and uncovered an otherwise hidden burden of disease. These data inform local Legionnaires' disease testing strategies, allow targeted antibiotic therapy, and help identify outbreaks and effective prevention strategies. The same approach might have similar benefits if applied elsewhere in the world.
Health Research Council of New Zealand.
Problematizing as a Scientific Endeavor Phillips, Anna McLean; Watkins, Jessica; Hammer, David
Physical review. Physics education research,
08/2017, Letnik:
13, Številka:
2
Journal Article
Recenzirano
Odprti dostop
The work of physics learners at all levels revolves around problems. Physics education research has inspired attention to the forms of these problems, whether conceptual or algorithmic, closed or ...open response, well or ill structured. Meanwhile, it has been the work of curriculum developers and instructors to develop these problems. Physics education research has supported these efforts with studies of students problem solving and the effects of different kinds of problems on learning. In this article we argue, first, that developing problems is central to the discipline of physics. It involves noticing a gap of understanding, identifying and articulating its precise nature, and motivating a community of its existence and significance. We refer to this activity as "problematizing," and we show its importance by drawing from writings in physics and philosophy of science. Second, we argue that students, from elementary age to adults, can problematize as part of their engaging in scientific inquiry. We present four cases, drawing from episodes vetted by a panel of collaborating faculty in science departments as clear instances of students doing science. Although neither we nor the scientists had problematizing in mind when screening cases, we found it across the episodes. We close with implications for instruction, including the value of helping students recognize and manage the situation of being confused but not yet having a clear question, and implications for research, including the need to build problematizing into our models of learning.
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