Site symmetry and crystal symmetry: a spherical tensor analysis

The relation between the properties of a specific crystallographic site and the properties of the full crystal is discussed by using spherical tensors. The concept of spherical tensors is introduced and the way it transforms under the symmetry operations of the site and from site to site is described in detail. The law of spherical tensor coupling is given and illustrated with the example of the electric dipole and quadrupole transitions in x-ray absorption spectroscopy. The main application of the formalism is the reduction of computation time in the calculation of the properties of crystals by band structure methods. The general approach is illustrated by the examples of substitutional chromium in spinel and substitutional vanadium in garnet.Comment: 27 pages, 3 figure

Experimental evidence of thermal fluctuations on the X-ray absorption near-edge structure at the aluminum K-edge

After a review of temperature-dependent experimental x-ray absorption near-edge structure (XANES) and related theoretical developments, we present the Al K-edge XANES spectra of corundum and beryl for temperature ranging from 300K to 930K. These experimental results provide a first evidence of the role of thermal fluctuation in XANES at the Al K-edge especially in the pre-edge region. The study is carried out by polarized XANES measurements of single crystals. For any orientation of the sample with respect to the x-ray beam, the pre-edge peak grows and shifts to lower energy with temperature. In addition temperature induces modifications in the position and intensities of the main XANES features. First-principles DFT calculations are performed for both compounds. They show that the pre-edge peak originates from forbidden 1s to 3s transitions induced by vibrations. Three existing theoretical models are used to take vibrations into account in the absorption cross section calculations: i) an average of the XANES spectra over the thermal displacements of the absorbing atom around its equilibrium position, ii) a method based on the crude Born-Oppenheimer approximation where only the initial state is averaged over thermal displacements, iii) a convolution of the spectra obtained for the atoms at the equilibrium positions with an approximate phonon spectral function. The theoretical spectra so obtained permit to qualitatively understand the origin of the spectral modifications induced by temperature. However the correct treatment of thermal fluctuation in XANES spectroscopy requires more sophisticated theoretical tools

Virtual patients design and its effect on clinical reasoning and student experience : a protocol for a randomised factorial multi-centre study

Background Virtual Patients (VPs) are web-based representations of realistic clinical cases. They are proposed as being an optimal method for teaching clinical reasoning skills. International standards exist which define precisely what constitutes a VP. There are multiple design possibilities for VPs, however there is little formal evidence to support individual design features. The purpose of this trial is to explore the effect of two different potentially important design features on clinical reasoning skills and the student experience. These are the branching case pathways (present or absent) and structured clinical reasoning feedback (present or absent). Methods/Design This is a multi-centre randomised 2x2 factorial design study evaluating two independent variables of VP design, branching (present or absent), and structured clinical reasoning feedback (present or absent).The study will be carried out in medical student volunteers in one year group from three university medical schools in the United Kingdom, Warwick, Keele and Birmingham. There are four core musculoskeletal topics. Each case can be designed in four different ways, equating to 16 VPs required for the research. Students will be randomised to four groups, completing the four VP topics in the same order, but with each group exposed to a different VP design sequentially. All students will be exposed to the four designs. Primary outcomes are performance for each case design in a standardized fifteen item clinical reasoning assessment, integrated into each VP, which is identical for each topic. Additionally a 15-item self-reported evaluation is completed for each VP, based on a widely used EViP tool. Student patterns of use of the VPs will be recorded. In one centre, formative clinical and examination performance will be recorded, along with a self reported pre and post-intervention reasoning score, the DTI. Our power calculations indicate a sample size of 112 is required for both primary outcomes

Collisional kinetics of non-uniform electric field, low-pressure, direct-current discharges in H2_{2}

A model of the collisional kinetics of energetic hydrogen atoms, molecules, and ions in pure H$_2$ discharges is used to predict H$_\alpha$ emission profiles and spatial distributions of emission from the cathode regions of low-pressure, weakly-ionized discharges for comparison with a wide variety of experiments. Positive and negative ion energy distributions are also predicted. The model developed for spatially uniform electric fields and current densities less than $10^{-3}$ A/m$^2$ is extended to non-uniform electric fields, current densities of $10^{3}$ A/m$^2$, and electric field to gas density ratios $E/N = 1.3$ MTd at 0.002 to 5 Torr pressure. (1 Td = $10^{-21}$ V m$^2$ and 1 Torr = 133 Pa) The observed far-wing Doppler broadening and spatial distribution of the H$_\alpha$ emission is consistent with reactions among H$^+$, H$_2^+$, H$_3^+$, and H$^-H$ ions, fast H atoms, and fast H$_2$ molecules, and with reflection, excitation, and attachment to fast H atoms at surfaces. The H$_\alpha$ excitation and H$^-$ formation occur principally by collisions of fast H, fast H$_2$, and H$^+$ with H$_2$. Simplifications include using a one-dimensional geometry, a multi-beam transport model, and the average cathode-fall electric field. The H$_\alpha$ emission is linear with current density over eight orders of magnitude. The calculated ion energy distributions agree satisfactorily with experiment for H$_2^+$ and H$_3^+$, but are only in qualitative agreement for H$^+$ and H$^-$. The experiments successfully modeled range from short-gap, parallel-plane glow discharges to beam-like, electrostatic-confinement discharges.Comment: Submitted to Plasmas Sources Science and Technology 8/18/201

Proposed Standards for Medical Education Submissions to the Journal of General Internal Medicine

To help authors design rigorous studies and prepare clear and informative manuscripts, improve the transparency of editorial decisions, and raise the bar on educational scholarship, the Deputy Editors of the Journal of General Internal Medicine articulate standards for medical education submissions to the Journal. General standards include: (1) quality questions, (2) quality methods to match the questions, (3) insightful interpretation of findings, (4) transparent, unbiased reporting, and (5) attention to human subjects’ protection and ethical research conduct. Additional standards for specific study types are described. We hope these proposed standards will generate discussion that will foster their continued evolution

Workplace learning from a socio-cultural perspective: creating developmental space during the general practice clerkship

Workplace learning in undergraduate medical education has predominantly been studied from a cognitive perspective, despite its complex contextual characteristics, which influence medical students’ learning experiences in such a way that explanation in terms of knowledge, skills, attitudes and single determinants of instructiveness is unlikely to suffice. There is also a paucity of research which, from a perspective other than the cognitive or descriptive one, investigates student learning in general practice settings, which are often characterised as powerful learning environments. In this study we took a socio-cultural perspective to clarify how students learn during a general practice clerkship and to construct a conceptual framework that captures this type of learning. Our analysis of group interviews with 44 fifth-year undergraduate medical students about their learning experiences in general practice showed that students needed developmental space to be able to learn and develop their professional identity. This space results from the intertwinement of workplace context, personal and professional interactions and emotions such as feeling respected and self-confident. These forces framed students’ participation in patient consultations, conversations with supervisors about consultations and students’ observation of supervisors, thereby determining the opportunities afforded to students to mind their learning. These findings resonate with other conceptual frameworks and learning theories. In order to refine our interpretation, we recommend that further research from a socio-cultural perspective should also explore other aspects of workplace learning in medical education

Benefits of knowledge-based interprofessional communication skills training in medical undergraduate education

OBJECTIVES: Good interprofessional communication is fundamental to effective teamworking in medicine. Finalmed is a private course that teaches the principles and methods of clinical presenting as an iterative technique of reasoning though clinical data. We have tested the efficacy of this technique using a questionnaire-based study. DESIGN: An anonymized 10-point Likert scale questionnaire was designed. SETTING: Questionnaires were distributed at five UK courses and two UAE courses. PARTICIPANTS: Questionnaires were given to all students attending these courses. MAIN OUTCOME MEASURES: The questionnaire included pre- and post-course questions addressing self-reported confidence in clinical presenting (CCP) and effectiveness in clinical presenting (ECP). We also asked whether attendees felt that clinical presenting should be integrated formally into medical school curricula. RESULTS: A total of 331/395 questionnaires were returned. Median improvement in CCP was 50% (P < 0.0001) and in ECP was 40% (P < 0.0001), irrespective of country of study, graduate entry status and whether the student felt that they had been exposed to these techniques previously. Students recorded a strong opinion in favour of integrating the content and style of the Finalmed course into their medical school curriculum, with 286 students (86%) recording a score of ≥8. CONCLUSION: Our study suggests that after a two- or three-day dedicated course, both self-reported confidence and effectiveness in clinical presenting significantly improve. Furthermore, students in the UK and the UAE returned a desire for integration into medical school curricula of IPC through the teaching of clinical presenting

Report on G4‐Med, a Geant4 benchmarking system for medical physics applications developed by the Geant4 Medical Simulation Benchmarking Group

Geant4 is a Monte Carlo code extensively used in medical physics for a wide range of applications, such as dosimetry, micro‐ and nano‐ dosimetry, imaging, radiation protection and nuclear medicine. Geant4 is continuously evolving, so it is crucial to have a system that benchmarks this Monte Carlo code for medical physics against reference data and to perform regression testing. To respond to these needs, we developed G4‐Med, a benchmarking and regression testing system of Geant4 for medical physics, that currently includes 18 tests. They range from the benchmarking of fundamental physics quantities to the testing of Monte Carlo simulation setups typical of medical physics applications. Both electromagnetic and hadronic physics processes and models within the pre‐built, Geant4 physics lists are tested. The tests included in G4‐Med are executed on the CERN computing infrastructure via the use of the geant‐val web application, developed at CERN for Geant4 testing. The physical observables can be compared to reference data for benchmarking and to results of previous Geant4 versions for regression testing purposes. This paper describes the tests included in G4‐Med and shows the results derived from the benchmarking of Geant4 10.5 against reference data. The results presented and discussed in this paper will aid users in tailoring physics lists to their particular application.D. Bolst acknowledges the support of the Australian Government Research Training Program Scholarship. M. A. Cort ́es-Giraldo, A. Perales, and J. M. Quesada acknowledge the financial support from the Spanish Ministry of Economy and Competitiveness under grant FPA2016-77689-C2-1-R. B. Faddegon and J. Ramos-M ́endez acknowledge partial financial support from the NIH grant U24CA215123. D. Bolst, S. Guatelli, D. Sakata, S.Incerti, and I. Kyriakou acknowledge financial support from the Australian Research Council, ARC DP170100967. S. Incerti acknowledges the financial support of CNRS through the IN2P3/MOVI Master Project and through the France-Greece PICS 8235 funding scheme. I. Kyriakou acknowledges additional financial support from the European Space Agency (Contract No. 4000126645/19/NL/BW). E. C. Simpson acknowledges financial support from the Australian Research Council under grant DP170102423. I. Sechopoulos and C. Fedon acknowledge financial support from the Susan G Komen Foundation for the Cure grant IIR13262248. S. Guatelli and D. Bolst acknowlege the use of computing resources of the Aus-tralian National Computing Infrastructure (NCI), through the NCMAS 2020 grant scheme

Online patient simulation training to improve clinical reasoning: a feasibility randomised controlled trial

Background Online patient simulations (OPS) are a novel method for teaching clinical reasoning skills to students and could contribute to reducing diagnostic errors. However, little is known about how best to implement and evaluate OPS in medical curricula. The aim of this study was to assess the feasibility, acceptability and potential effects of eCREST — the electronic Clinical Reasoning Educational Simulation Tool. Methods A feasibility randomised controlled trial was conducted with final year undergraduate students from three UK medical schools in academic year 2016/2017 (cohort one) and 2017/2018 (cohort two). Student volunteers were recruited in cohort one via email and on teaching days, and in cohort two eCREST was also integrated into a relevant module in the curriculum. The intervention group received three patient cases and the control group received teaching as usual; allocation ratio was 1:1. Researchers were blind to allocation. Clinical reasoning skills were measured using a survey after 1 week and a patient case after 1 month. Results Across schools, 264 students participated (18.2% of all eligible). Cohort two had greater uptake (183/833, 22%) than cohort one (81/621, 13%). After 1 week, 99/137 (72%) of the intervention and 86/127 (68%) of the control group remained in the study. eCREST improved students’ ability to gather essential information from patients over controls (OR = 1.4; 95% CI 1.1–1.7, n = 148). Of the intervention group, most (80/98, 82%) agreed eCREST helped them to learn clinical reasoning skills. Conclusions eCREST was highly acceptable and improved data gathering skills that could reduce diagnostic errors. Uptake was low but improved when integrated into course delivery. A summative trial is needed to estimate effectiveness