5,098 research outputs found

    Very short answer questions: a novel approach to summative assessments in pathology

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    Background A solid understanding of the science underpinning treatment is essential for all doctors. Pathology teaching and assessment are fundamental components of the undergraduate medicine curriculum. Assessment drives learning and the choice of assessments influences students’ learning behaviours. The use of multiple-choice questions is common but is associated with significant cueing and may promote ‘rote learning’. Essay-type questions and Objective Structured Clinical Examinations (OSCEs) are resource-intensive in terms of delivery and marking, and do not allow adequate sampling of the curriculum. To address these limitations, we used a novel online tool to administer Very Short Answer questions (VSAQs) and evaluated the utility of the VSAQs in an undergraduate summative pathology assessment. Methods A group of 285 medical students took the summative assessment, comprising 50 VSAQs, 50 single best answer questions (SBAQs), and 75 extended matching questions (EMQs). The VSAQs were machine-marked against pre-approved responses, and subsequently reviewed by a panel of pathologists, with the software remembering all new marking judgements. Results The total time taken to mark all 50 VSAQs for all 285 students was 5 hours, compared to 70 hours required to manually mark an equivalent number of questions in a paper-based pathology exam. The median percentage score for the VSA test (72%) was significantly lower than that of the SBAQs (80%) and EMQs (84%), p <0.0001. VSAQs had a higher Cronbach alpha (0.86) than SBAQs (0.76), and EMQs (0.77). VSAQs, SBAQs and EMQs had a mean point-biserial of 0.35, 0.30 and 0.28, respectively. Conclusions VSAQs are an acceptable, reliable and discriminatory method for assessing pathology, and may enhance students’ understanding of how pathology supports clinical decision-making and clinical care by changing learning behaviour

    Association of Ambient Air Pollution with Respiratory Hospitalization in a Government-Designated “Area of Concern”: The Case of Windsor, Ontario

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    This study is part of a larger research program to examine the relationship between ambient air quality and health in Windsor, Ontario, Canada. We assessed the association between air pollution and daily respiratory hospitalization for different age and sex groups from 1995 to 2000. The pollutants included were nitrogen dioxide, sulfur dioxide, carbon monoxide, ozone, particulate matter ≀10 ÎŒm in diameter (PM(10)), coefficient of haze (COH), and total reduced sulfur (TRS). We calculated relative risk (RR) estimates using both time-series and case-crossover methods after controlling for appropriate confounders (temperature, humidity, and change in barometric pressure). The results of both analyses were consistent. We found associations between NO(2), SO(2), CO, COH, or PM(10) and daily hospital admission of respiratory diseases especially among females. For females 0–14 years of age, there was 1-day delayed effect of NO(2) (RR = 1.19, case-crossover method), a current-day SO(2) (RR = 1.11, time series), and current-day and 1- and 2-day delayed effects for CO by case crossover (RR = 1.15, 1.19, 1.22, respectively). Time-series analysis showed that 1-day delayed effect of PM(10) on respiratory admissions of adult males (15–64 years of age), with an RR of 1.18. COH had significant effects on female respiratory hospitalization, especially for 2-day delayed effects on adult females, with RRs of 1.15 and 1.29 using time-series and case-crossover analysis, respectively. There were no significant associations between O(3) and TRS with respiratory admissions. These findings provide policy makers with current risks estimates of respiratory hospitalization as a result of poor ambient air quality in a government designated “area of concern.

    Properties of Ridges in Elastic Membranes

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    When a thin elastic sheet is confined to a region much smaller than its size the morphology of the resulting crumpled membrane is a network of straight ridges or folds that meet at sharp vertices. A virial theorem predicts the ratio of the total bending and stretching energies of a ridge. Small strains and curvatures persist far away from the ridge. We discuss several kinds of perturbations that distinguish a ridge in a crumpled sheet from an isolated ridge studied earlier (A. E. Lobkovsky, Phys. Rev. E. 53 3750 (1996)). Linear response as well as buckling properties are investigated. We find that quite generally, the energy of a ridge can change by no more than a finite fraction before it buckles.Comment: 13 pages, RevTeX, acknowledgement adde

    NMR Simulation of an Eight-State Quantum System

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    The propagation of excitation along a one-dimensional chain of atoms is simulated by means of NMR. The physical system used as an analog quantum computer is a nucleus of 133-Cs (spin 7/2) in a liquid crystalline matrix. The Hamiltonian of migration is simulated by using a special 7-frequency pulse, and the dynamics is monitored by following the transfer of population from one of the 8 spin energy levels to the other.Comment: 10 pages, 3 figure

    Conceptual and practical challenges for implementing the communities of practice model on a national scale - a Canadian cancer control initiative

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    <p>Abstract</p> <p>Background</p> <p>Cancer program delivery, like the rest of health care in Canada, faces two ongoing challenges: to coordinate a pan-Canadian approach across complex provincial jurisdictions, and to facilitate the rapid translation of knowledge into clinical practice. Communities of practice, or CoPs, which have been described by Etienne Wenger as a collaborative learning platform, represent a promising solution to these challenges because they rely on bottom-up rather than top-down social structures for integrating knowledge and practice across regions and agencies. The communities of practice model has been realized in the corporate (e.g., Royal Dutch Shell, Xerox, IBM, etc) and development (e.g., World Bank) sectors, but its application to health care is relatively new. The Canadian Partnership Against Cancer (CPAC) is exploring the potential of Wenger's concept in the Canadian health care context. This paper provides an in-depth analysis of Wenger's concept with a focus on its applicability to the health care sector.</p> <p>Discussion</p> <p>Empirical studies and social science theory are used to examine the utility of Wenger's concept. Its value lies in emphasizing learning from peers and through practice in settings where innovation is valued. Yet the communities of practice concept lacks conceptual clarity because Wenger defines it so broadly and sidelines issues of decision making within CoPs. We consider the implications of his broad definition to establishing an informed nomenclature around this specific type of collaborative group. The CoP Project under CPAC and communities of practice in Canadian health care are discussed.</p> <p>Summary</p> <p>The use of communities of practice in Canadian health care has been shown in some instances to facilitate quality improvements, encourage buy in among participants, and generate high levels of satisfaction with clinical leadership and knowledge translation among participating physicians. Despite these individual success stories, more information is required on how group decisions are made and applied to the practice world in order to leverage the potential of Wenger's concept more fully, and advance the science of knowledge translation within an accountability framework.</p

    Chronic liver allograft rejection in a population treated primarily with tacrolimus as baseline immunosuppression: Long-term follow-up and evaluation of features for histopathological staging

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    Background: Predisposing factors, long-term occurrence, and histopathological changes associated with recovery or progression to allograft failure from chronic rejection (CR) were studied in adult patients treated primarily with tacrolimus. Methods: CR cases were identified using stringent criteria applied to a retrospective review of computerized clinicopathological data and slides. Results: After 1973 days median follow- up, 35 (3.3%) of 1049 primary liver allograft recipients first developed CR between 16 and 2532 (median 242) days. The most significant risk factors for CR were the number (P40 years (P<0.03). Other demographic and matching parameters were not associated with CR in this cohort. Ten patients died with, but not of, CR. Eight required retransplantation because of CR at a median of 268 days. Ten resolved either histologically or by normalization of liver injury tests over a median of 548 days. CR persisted for 340 to 2116 days in the remaining seven patients. More extensive bile duct loss (P<0.01), small arterial loss (p<0.03), foam cell clusters (P<0.01) and higher total bilirubin (p<0.02) and aspartate aminotransferase (p<0.03) were associated with allograft failure from CR. Conclusions: Early chronic liver allograft rejection is potentially reversible and a combination of histological, clinical and laboratory data can be use to stage CR. Unique immunological and generative properties of liver allografts, which lead to low incidence and reversibility of early CR, can provide insights into transplantation biology

    Patient outcomes and characteristics in a contemporary quaternary Canadian cardiac intensive care unit

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    BACKGROUND: The modern-day cardiac intensive care unit (CICU) has evolved to care for patients with acute critical cardiac illness. We describe the current population of cardiac patients in a quaternary CICU. METHODS: Consecutive CICU patients admitted to the CICU at the Toronto General Hospital from 2014 to 2020 were studied. Patient demographics, admission diagnosis, critical care resources, complications, in-hospital mortality, and CICU and hospital length of stay were recorded. RESULTS: A total of 8865 consecutive admissions occurred, with a median age of 64.9 years. The most common primary cardiac diagnoses were acute decompensated heart failure (17.8%), non ST-elevation myocardial infarction (16.8%), ST-elevation myocardial infarction (15.5%), and arrhythmias (14.7%). Cardiogenic shock was seen in 13.2%, and out-of-hospital cardiac arrest in 4.1%. A noncardiovascular admission diagnosis accounted for 13.9% of the cases. Over the period studied, rates of admission were higher for cardiogenic shock (P < 0.001 for trend), with a higher use of critical care resources. Additionally, rates of admission were higher in female patients and those who had chronic kidney disease and diabetes. The in-hospital mortality rate of all CICU admissions was 13.2%, and it was highest in those with noncardiac conditions, compared to the rate in those with cardiac diagnoses (29.4% vs 10.6%, P < 0.001). CONCLUSIONS: Given the trends of higher acuity of patients with cardiac critical illness, with higher use of critical care resources, education streams for critical care within cardiology, and alternative pathways of care for patients who have lower-acuity cardiac disease remain imperative to manage this evolving population

    Fully Automated Myocardial Strain Estimation from Cardiovascular MRI–tagged Images Using a Deep Learning Framework in the UK Biobank

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    Purpose: To demonstrate the feasibility and performance of a fully automated deep learning framework to estimate myocardial strain from short-axis cardiac magnetic resonance tagged images. Methods and Materials: In this retrospective cross-sectional study, 4508 cases from the UK Biobank were split randomly into 3244 training and 812 validation cases, and 452 test cases. Ground truth myocardial landmarks were defined and tracked by manual initialization and correction of deformable image registration using previously validated software with five readers. The fully automatic framework consisted of 1) a convolutional neural network (CNN) for localization, and 2) a combination of a recurrent neural network (RNN) and a CNN to detect and track the myocardial landmarks through the image sequence for each slice. Radial and circumferential strain were then calculated from the motion of the landmarks and averaged on a slice basis. Results: Within the test set, myocardial end-systolic circumferential Green strain errors were -0.001 +/- 0.025, -0.001 +/- 0.021, and 0.004 +/- 0.035 in basal, mid, and apical slices respectively (mean +/- std. dev. of differences between predicted and manual strain). The framework reproduced significant reductions in circumferential strain in diabetics, hypertensives, and participants with previous heart attack. Typical processing time was ~260 frames (~13 slices) per second on an NVIDIA Tesla K40 with 12GB RAM, compared with 6-8 minutes per slice for the manual analysis. Conclusions: The fully automated RNNCNN framework for analysis of myocardial strain enabled unbiased strain evaluation in a high-throughput workflow, with similar ability to distinguish impairment due to diabetes, hypertension, and previous heart attack.Comment: accepted in Radiology Cardiothoracic Imagin

    Decoy state quantum key distribution with two-way classical post-processing

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    Decoy states have recently been proposed as a useful method for substantially improving the performance of quantum key distribution protocols when a coherent state source is used. Previously, data post-processing schemes based on one-way classical communications were considered for use with decoy states. In this paper, we develop two data post-processing schemes for the decoy-state method using two-way classical communications. Our numerical simulation (using parameters from a specific QKD experiment as an example) results show that our scheme is able to extend the maximal secure distance from 142km (using only one-way classical communications with decoy states) to 181km. The second scheme is able to achieve a 10% greater key generation rate in the whole regime of distances
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