Monte Carlo studies of a novel X-ray tube anode design

When energetic electrons are incident on high atomic number absorbers, a substantial fraction is back-scattered. This phenomenon is responsible for several undesirable effects in X-ray tubes, in particular a reduction in the X-ray output. The extent of this shortfall has been estimated by using Monte Carlo simulation to start electrons at increasing depth inside the anode, the results indicating that an output enhancement of nearly 50% could be achieved in principle if the electrons wasted in back-scatter events could be trapped inside a tungsten anode. To test this idea a further set of simulations were done for a novel anode geometry. Results showed that X-ray tube efficiencies might be substantially enhanced by this approach.http://www.sciencedirect.com/science/article/B6TVT-43P41Y7-30/1/526566f6ea15332c302cdad2886e583

Working memory, attention and compositionality

Es una práctica habitual en Psicología desarrollar microteorías para explicar datos muy concretos obtenidos en un conjunto limitado de tareas. Cuando todo el peso de la elaboración teórica recae en unos datos empíricos específicos sin tener en cuenta otras restricciones teóricas más generales, los grados de libertad para elaborar un modelo son en general muchos y esto hace que la proliferación de modelos sea considerable sin que se disponga de las suficientes restricciones para descartar cuáles son inadecuados. Las discusiones sobre qué modelos son los adecuados se enquistan en polémicas interminables. Teorías más generales permitirían integrar un mayor número de datos (empíricos y computacionales) en un todo con sentido y así se podrían descartar, de forma más simple y efectiva, los modelos que no se ajustan a estas restricciones. En este trabajo hemos intentado integrar en una todo con sentido algunas de las teorías existentes sobre un conjunto amplio de procesos (memoria de trabajo, razonamiento, procesamiento visual, procesamiento de lenguaje) y una amplia variedad de datos psicológicos, neurofisiológicos y computacionales. Como resultado se obtiene una teoría más general que, de forma razonable, permite imponer un amplio conjunto de restricciones a la hora de elaborar modelos sobre ciertos fenómenos y permite entre otras cosas descartar como inadecuados modelos actuales que gozan de cierto prestigio.It is standard practice in Psychology to develop microtheories to explain very specific data obtained from a reduced set of tasks. If more general theoretical constraints are disregarded, the results may be an uncontrolled proliferation of models. Discussions of which models are appropiate and which are not cause end less controversy. With a more general theory, one could put together a larger body of data (both empirical and computational) into a meaningful whole and could reject, simply and affectively, the models that do not meet the theory’s constraints. In this paper we bring together some of the existing theories on a set of processes (working memory, reasoning, visual and language processing) and a large variety of psychological, neurophysiological and computational data. We thus formulate a more general theory which, in a reasonable way, imposes a larger set of constraints on the preparation of models and challenges the validity of some inappropiate models that currently enjoy a certain prestige

Working memory, attention and compositionality

Es una práctica habitual en Psicología desarrollar microteorías para explicar datos muy concretos obtenidos en un conjunto limitado de tareas. Cuando todo el peso de la elaboración teórica recae en unos datos empíricos específicos sin tener en cuenta otras restricciones teóricas más generales, los grados de libertad para elaborar un modelo son en general muchos y esto hace que la proliferación de modelos sea considerable sin que se disponga de las suficientes restricciones para descartar cuáles son inadecuados. Las discusiones sobre qué modelos son los adecuados se enquistan en polémicas interminables. Teorías más generales permitirían integrar un mayor número de datos (empíricos y computacionales) en un todo con sentido y así se podrían descartar, de forma más simple y efectiva, los modelos que no se ajustan a estas restricciones. En este trabajo hemos intentado integrar en una todo con sentido algunas de las teorías existentes sobre un conjunto amplio de procesos (memoria de trabajo, razonamiento, procesamiento visual, procesamiento de lenguaje) y una amplia variedad de datos psicológicos, neurofisiológicos y computacionales. Como resultado se obtiene una teoría más general que, de forma razonable, permite imponer un amplio conjunto de restricciones a la hora de elaborar modelos sobre ciertos fenómenos y permite entre otras cosas descartar como inadecuados modelos actuales que gozan de cierto prestigio.It is standard practice in Psychology to develop microtheories to explain very specific data obtained from a reduced set of tasks. If more general theoretical constraints are disregarded, the results may be an uncontrolled proliferation of models. Discussions of which models are appropiate and which are not cause end less controversy. With a more general theory, one could put together a larger body of data (both empirical and computational) into a meaningful whole and could reject, simply and affectively, the models that do not meet the theory’s constraints. In this paper we bring together some of the existing theories on a set of processes (working memory, reasoning, visual and language processing) and a large variety of psychological, neurophysiological and computational data. We thus formulate a more general theory which, in a reasonable way, imposes a larger set of constraints on the preparation of models and challenges the validity of some inappropiate models that currently enjoy a certain prestige

Impact of the ABCDE triage in primary care emergency department on the number of patient visits to different parts of the health care system in Espoo City

<p>Abstract</p> <p>Background</p> <p>Many Finnish emergency departments (ED) serve both primary and secondary health care patients and are therefore referred to as combined emergency departments. Primary care doctors are responsible for the initial assessment and treatment. They, thereby, also regulate referral and access to secondary care. Primary health care EDs are easy for the public to access, leading to non-acute patient visits to the emergency department. This has caused increased queues and unnecessary difficulties in providing immediate treatment for urgent patients. The primary aim of this study was to assess whether the flow of patients was changed by implementing the ABCDE-triage system in the EDs of Espoo City, Finland.</p> <p>Methods</p> <p>The numbers of monthly visits to doctors were recorded before and after intervention in Espoo primary care EDs. To study if the implementation of the triage system redirects patients to other health services, the numbers of monthly visits to doctors were also scored in the private health care, the public sector health services of Espoo primary care during office hours and local secondary health care ED (Jorvi hospital). A face-to-face triage system was applied in the primary care EDs as an attempt to provide immediate treatment for the most acute patients. It is based on the letters A (patient sent directly to secondary care), B (to be examined within 10 min), C (to be examined within 1 h), D (to be examined within 2 h) and E (no need for immediate treatment) for assessing the urgency of patients' treatment needs. The first step was an initial patient assessment by a health care professional (triage nurse). The introduction of this triage system was combined with information to the public on the "correct" use of emergency services.</p> <p>Results</p> <p>After implementation of the ABCDE-triage system the number of patient visits to a primary care doctor decreased by up to 24% (962 visits/month) as compared to the three previous years in the EDs. The Number of visits to public sector GPs during office hours did not alter. Implementation of ABCDE-triage combined with public guidance was associated with decreased total number of doctor visits in public health care. During same period, the number of patient visits in the private health care increased. Simultaneously, the number of doctor visits in secondary health care ED did not alter.</p> <p>Conclusions</p> <p>The present ABCDE-triage system combined with public guidance may reduce patient visits to primary health care EDs but not to the secondary health care EDs. Limiting the access of less urgent patients to ED may redirect the demands of patients to private sector rather than office hours GP services.</p

Exploring medical student learning in the large group teaching environment: examining current practice to inform curricular development

Background Lectures continue to be an efficient and standardised way to deliver information to large groups of students. It has been well documented that students prefer interactive lectures, based on active learning principles, to didactic teaching in the large group setting. Despite this, it is often the case than many students do not engage with active learning tasks and attempts at interaction. By exploring student experiences, expectations and how they use lectures in their learning we will provide recommendations for faculty to support student learning both in the lecture theatre and during personal study time. Methods This research employed a hermeneutic phenomenological approach. Three focus groups, consisting of 19 students in total, were used to explore the experiences of second year medical students in large group teaching sessions. Using generic thematic data analysis, these accounts have been developed into a meaningful account of experience. Results This study found there to be a well-established learning culture amongst students and with it, expectations as to the format of teaching sessions. Furthermore, there were set perceptions about the student role within the learning environment which had many implications, including the way that innovative teaching methods were received. Student learning was perceived to take place outside the lecture theatre, with a large emphasis placed on creating resources that can be taken away to use in personal study time. Conclusions Presented here is a constructive review of reasons for student participation, interaction and engagement in large group teaching sessions. Based on this are recommendations constructed with the view to aid educators in engaging students within this setting. Short term, educators can implement strategies that monopolise on the established learning culture of students to encourage engagement with active learning strategies. Long term, it would be beneficial for educators to consider ways to shift the current student learning culture to one that embraces an active learning curriculum