Improving case study research in medical education: A systematised review

Context:Case study research (CSR) is a research approach that guides holistic investigation of a real phenomenon. This approach may be useful in medical education to provide critical analyses of teaching and learning, and to reveal the underlying elements of leadership and innovation. There are variations in the definition, design and choice of methods, which may diminish the value of CSR as a form of inquiry.Objectives:This paper reports an analysis of CSR papers in the medical education literature. The review aims to describe how CSR has been used and how more consistency might be achieved to promote understanding and value.Methods:A systematised review was undertaken to quantify the number of CSR articles published in scholarly medical education journals over the last 10 years. A typology of CSR proposed by Thomas and Myers to integrate the various ways in which CSR is constructed was applied.Results:Of the 362 full‐text articles assessed, 290 were excluded as they did not meet the eligibility criteria; 76 of these were titled ‘case study’. Of the 72 included articles, 50 used single‐case and 22 multi‐case design; 46 connected with theory and 26 were atheoretical. In some articles it was unclear what the subject was or how the subject was being analysed.Conclusions:In this study, more articles titled ‘case study’ failed than succeeded in meeting the eligibility criteria. Well‐structured, clearly written CSR in medical education has the potential to increase understanding of more complex situations, but this review shows there is considerable variation in how it is conducted, which potentially limits its utility and translation into education practice. Case study research might be of more value in medical education if researchers were to follow more consistently principles of design, and harness rich observation with connection of ideas and knowledge to engage the reader in what is most interesting

The value of arboreta in South Africa

Significance:• Arboreta are documented, living collections of ligneous species cultivated for research, education and display.• Arboreta are a valuable resource for the forestry industry as gene banks.• Arboreta, together with botanic gardens, form a useful network of sentinel sites for plant pathogens and invasive species.• A survey of the species composition and status     of  arboreta in South Africa would be an important contribution to our botanical knowledge

Mutation accumulation in exponentially growing populations

Stochastic models of mutation accumulation in exponentially growing cellular populations are widely used to quantify cancer and bacterial evolution. Across manifold scenarios, recurrent research questions are: how many cells exist with a given set of alterations, and how long will it take for these cells to appear. These questions have been tackled in special cases, often within a branching processes framework. However, the general situation of cells sequentially acquiring an arbitrary number of mutations which may be selectively advantageous, neutral, or disadvantageous remains unaddressed. Here, we consider this setting in the biologically relevant limiting regimes of large times and small mutation rates. We provide analytic expressions for the number, and arrival time, of cells with $n$ mutations. Universal probability distributions for both quantities are presented, and the consequences of our results on cancer driver mutation accumulation and bacterial fluctuation assays are highlighted

Isospin-violating dark matter at liquid noble detectors: new constraints, future projections, and an exploration of target complementarity

There is no known reason that dark matter interactions with the Standard Model should couple to neutrons and protons in the same way. This isospin violation can have large consequences, modifying the sensitivity of existing and future direct detection experimental constraints by orders of magnitude. Previous works in the literature have focused on the zero-momentum limit which has its limitations when extending the analysis to the Non-Relativistic Effective Field Theory basis (NREFT). In this paper, we study isospin violation in a detailed manner, paying specific attention to the experimental setups of liquid noble detectors. We analyse two effective Standard Model gauge invariant models as interesting case studies as well as the more model-independent NREFT operators. This work demonstrates the high degree of complementarity between the target nuclei xenon and argon. Most notably, we show that the Standard Model gauge-invariant formulation of the standard spin-dependent interaction often generates a sizeable response from argon, a target nuclei with zero spin. This work is meant as an update and a useful reference to model builders and experimentalists.Comment: 22 pages in total, 13 figures, 1 table, 3 appendices. Data from the main results of this paper is available at https://doi.org/10.1140/epjc/s10052-023-11826-

The Relationship Between the Number of Shots and the Quality of Gamma Knife Radiosurgeries

Radiosurgery is a non-invasive alternative to brain surgery that uses a single focused application of high radiation to destroy intracerebral target tissues. A Gamma Knife delivers such treatments by using 201 cylindrically collimated cobalt-60 sources that are arranged in a hemispherical pattern and aimed to a common focal point. The accumulation of radiation at the focal point, called a \shot due to the spherical nature of the dose distribution, is used to ablate (or destroy) target tissue in the brain. If the target is small and spherical, it is easily treated by choosing one of four available collimators (4, 8, 14, or 18 mm). For large, irregular targets, multiple shots are typically required to treat the entire lesion, and the process of determining the optimal arrangement and number of shots is complex. In this research, fast simulated annealing and a novel objective function are used to investigate the relationship between the number of shots and the quality of the resulting treatment. Sets of 5, 10, 25, 50, and an unrestricted number of shots are studied for an arteriovenous malformation (AVM). As the shot limit increases the following improvements in plan quality are observed: the conformity of the prescription isodose line increases, the lesion dose becomes more homogeneous, and an increase use of smaller collimators to deposit dose. Large improvements in plan quality are realized by increasing the number of shots from 5 to 50, and to achieve a similar magnitude of improvement past 50 requires an increase over 1500 shots for the complex lesion investigated. This observation suggests that it is clinically valuable to improve the Gamma Knife\u27s delivery capabilities so that 50 shot treatments are possible

In Defense of a K-12 Reading Perspective

Teaching students to read is a very important goal in the public schools. This objective has been established because professionals believe that being able to read facilitates students\u27 chances for future success and happiness. Yet, when definitions of literacy are reviewed and the reading ability of the adult population in the United States is considered, data indicate taht millions of Americans are illiterate. In order to revers this downward spiral, the skill of reading must be viewed as a continuing process. Such a supposition would be adopting and implementing a K-12 perspective

Calcium transients in single adrenal chromaffin cells detected with aequorin

AbstractThe effect of 55 mM K+ and nicotine on intracellular free calcium was monitored in bovine adrenal chromaffin cells microinjected with aequorin. In contrast to results with quin 2, which suggested that stimulation of chromaffin cells resulted in sustained rises in free calcium, aequorin measurements showed that 55 mM K+ and nicotine resulted in a transient (60–90 s) elevation of free calcium. The peak free calcium and duration of the transient elicited by nicotine were dose-dependent. The concentration of nicotine (10 μM) giving a maximal secretory response gave a peak rise in free calcium of up to 1 μM. 55 mM K+ which only releases 30% of the catecholamine released by 10 μM nicotine generated a calcium transient indistinguishable from that due to 10 μM nicotine. These results support the idea that nicotinic agonists generate an alternative second messenger in addition to the rise in free calcium