258 research outputs found
Determination of vibration-rotation lines intensities from absorption Fourier spectra
The method presented allows the line intensities to be calculated from either their equivalent widths, heights, or quantities deduced from spectra obtained by Fourier spectrometry. This method has proven its effectiveness in measuring intensities of 60 lines of the molecule H2O with a precision of 10%. However, this method cannot be applied to isolated lines
Environnement intérieur : vers une prise de conscience française de l'enjeu sanitaire
National audienceLargement prise en compte depuis une vingtaine d'années aux Etats-Unis, au Canada et dans les pays nord-européens, la problématique de l'environnement intérieur semble émerger concrÚtement en France
Ătude expĂ©rimentale et simulation des conditions d'extraction d'un faisceau d'ions multichargĂ©s d'une source Ă rĂ©sonance cyclotronique Ă©lectronique
This thesis concerns the beam extraction studies of ECR Ion Sources for the SPIRAL project at GANIL (France). The optical properties (i.e. the emittances) of the radioactive ion beam production source is a crucial point in this project. We performed emittance measurements with a very high transport efficiency and developed a computer code for simulating the extraction and transport conditions. This simulation takes into account all the parameters acting on the extraction process: the characteristics of the ions and electrons emitted by the plasma, their space and energy distributions, the space charge, the magnetic filed of the source and the accelerating electric field. We explained the evolution of the emittances for two different types of ECR Ion Source. The simulation-experiment comparison showed us that the magnetic field and the intrinsic energy of the ions seem to be the most important parameters for explaining the overall emittance behaviour of the ECRIS. We precise their values and comment them.Cette thÚse entre dans le cadre du projet SPIRAL (SystÚme de Production d'Ions Radioactifs Accélérés en Ligne) au GANIL (Grand Accélérateur National d'Ions Lourds) à Caen. Ce projet, utilisant une source d'ions de type ECR, impose que le faisceau extrait ait de trÚs bonnes qualités optiques. L'étude des conditions d'extraction du faisceau et de formation des émittances s'impose alors. L'approche est faite par l'expérience et la simulation. Dans un premier temps, des mesures d'émittances de faisceaux ont été effectuées avec une efficacité de transport maximale. Ensuite, un programme informatique, simulant les conditions d'extraction et de transport d'un faisceau de source ECR, a été développé puis testé. Il tient compte de tous les paramÚtres mis en jeu dans le processus d'extraction: la nature des ions et des électrons issus du plasma, leurs distributions spatiale et énergétique, la charge d'espace, le champ magnétique de fuite de la source et le champ électrique extracteur. Il est alors devenu possible de rendre compte de l'évolution des émittances de deux types de sources ECR différentes. La comparaison simulation-expérience a aussi permis de dégager les paramÚtres principaux influençant les émittances. Ainsi, le champ magnétique et l'énergie intrinsÚque des ions jouent des rÎles primordiaux dont les importances relatives sont précisées et commentées dans ce manuscrit
Managing the complexity of doing it all : an exploratory study on students' experiences when trained stepwise in conducting consultations
Background: At most medical schools the components required to conduct a consultation, medical knowledge, communication, clinical reasoning and physical examination skills, are trained separately. Afterwards, all the knowledge and skills students acquired must be integrated into complete consultations, an art that lies at the heart of the medical profession. Inevitably, students experience conducting consultations as complex and challenging. Literature emphasizes the importance of three didactic course principles: moving from partial tasks to whole task learning, diminishing supervisors' support and gradually increasing students' responsibility. This study explores students' experiences of an integrated consultation course using these three didactic principles to support them in this difficult task.
Methods: Six focus groups were conducted with 20 pre-clerkship and 19 clerkship students in total. Discussions were audiotaped, transcribed and analysed by Nvivo using the constant comparative strategy within a thematic analysis.
Results: Conducting complete consultations motivated students in their learning process as future physician. Initially, students were very much focused on medical problem solving. Completing the whole task of a consultation obligated them to transfer their theoretical medical knowledge into applicable clinical knowledge on the spot. Furthermore, diminishing the support of a supervisor triggered students to reflect on their own actions but contrasted with their increased appreciation of critical feedback. Increasing students' responsibility stimulated their active learning but made some students feel overloaded. These students were anxious to miss patient information or not being able to take the right decisions or to answer patients' questions, which sometimes resulted in evasive coping techniques, such as talking faster to prevent the patient asking questions.
Conclusion: The complex task of conducting complete consultations should be implemented early within medical curricula because students need time to organize their medical knowledge into applicable clinical knowledge. An integrated consultation course should comprise a step-by-step teaching strategy with a variety of supervisors' feedback modi, adapted to students' competence. Finally, students should be guided in formulating achievable standards to prevent them from feeling overloaded in practicing complete consultations with simulated or real patients
Personal control of the indoor environment in offices: Relations with building characteristics, influence on occupant perception and reported symptoms related to the building-the officair project
Personal control over various indoor environment parameters, especially in the last decades, appear to have a significant role on occupants' comfort, health and productivity. To reveal this complex relationship, 7441 occupants of 167 recently built or retrofitted office buildings in eight European countries participated in an online survey about personal/health/work data as well as physical/psycho-social information. The relationship between the types of control available over indoor environments and the perceived personal control of the occupants was examined, as well as the combined effect of the control parameters on the perceived comfort using multilevel statistical models. The results indicated that most of the occupants have no or low control on noise. Half of the occupants declared no or low control on ventilation and temperature conditions. Almost one-third of them remarked that they do not have satisfactory levels of control for lighting and shading from sun conditions. The presence of operable windows was shown to influence occupants' control perception over temperature, ventilation, light and noise. General building characteristics, such as floor number and floor area, office type, etc., helped occupants associate freedom positively with control perception. Combined controlling parameters seem to have a strong relation with overall comfort, as well as with perception regarding amount of privacy, office layout and decoration satisfaction. The results also indicated that occupants with more personal control may have less building-related symptoms. Noise control parameter had the highest impact on the occupants' overall comfort
A prospective randomized trial of content expertise versus process expertise in small group teaching
Article deposited according to agreement with BMC, December 6, 2010.YesFunding provided by the Open Access Authors Fund
Involvement in teaching improves learning in medical students: a randomized cross-over study
<p>Abstract</p> <p>Background</p> <p>Peer-assisted learning has many purported benefits including preparing students as educators, improving communication skills and reducing faculty teaching burden. But comparatively little is known about the effects of teaching on learning outcomes of peer educators in medical education.</p> <p>Methods</p> <p>One hundred and thirty-five first year medical students were randomly allocated to 11 small groups for the Gastroenterology/Hematology Course at the University of Calgary. For each of 22 sessions, two students were randomly selected from each group to be peer educators. Students were surveyed to estimate time spent preparing as peer educator versus group member. Students completed an end-of-course 94 question multiple choice exam. A paired t-test was used to compare performance on clinical presentations for which students were peer educators to those for which they were not.</p> <p>Results</p> <p>Preparation time increased from a mean (SD) of 36 (33) minutes baseline to 99 (60) minutes when peer educators (Cohen's <it>d </it>= 1.3; p < 0.001). The mean score (SD) for clinical presentations in which students were peer educators was 80.7% (11.8) compared to77.6% (6.9) for those which they were not (<it>d </it>= 0.33; <it>p </it>< 0.01).</p> <p>Conclusion</p> <p>Our results suggest that involvement in teaching small group sessions improves medical students' knowledge acquisition and retention.</p
Optimized two-dimensional thin layer chromatography to monitor the intracellular concentration of acetyl phosphate and other small phosphorylated molecules
Acetyl phosphate (acetyl-P) serves critical roles in coenzyme A recycling and ATP synthesis. It is the intermediate of the Pta-AckA pathway that inter-converts acetyl-coenzyme A and acetate. Acetyl-P also can act as a global signal by donating its phosphoryl group to specific two-component response regulators. This ability derives from its capacity to store energy in the form of a high-energy phosphate bond. This bond, while critical to its function, also destabilizes acetyl-P in cell extracts. This lability has greatly complicated biochemical analysis, leading in part to widely varying acetyl-P measurements. We therefore developed an optimized protocol based on two-dimensional thin layer chromatography that includes metabolic labeling under aerated conditions and careful examination of the integrity of acetyl-P within extracts. This protocol results in greatly improved reproducibility, and thus permits precise measurements of the intracellular concentration of acetyl-P, as well as that of other small phosphorylated molecules
Assessing Human Exposure to SVOCs in Materials, Products, and Articles : A Modular Mechanistic Framework
A critical review of the current state of knowledge of chemical emissions from indoor sources, partitioning among indoor compartments, and the ensuing indoor exposure leads to a proposal for a modular mechanistic framework for predicting human exposure to semivolatile organic compounds (SVOCs). Mechanistically consistent source emission categories include solid, soft, frequent contact, applied, sprayed, and high temperature sources. Environmental compartments are the gas phase, airborne particles, settled dust, indoor surfaces, and clothing. Identified research needs are the development of dynamic emission models for several of the source emission categories and of estimation strategies for critical model parameters. The modular structure of the framework facilitates subsequent inclusion of new knowledge, other chemical classes of indoor pollutants, and additional mechanistic processes relevant to human exposure indoors. The framework may serve as the foundation for developing an open-source community model to better support collaborative research and improve access for application by stakeholders. Combining exposure estimates derived using this framework with toxicity data for different end points and toxicokinetic mechanisms will accelerate chemical risk prioritization, advance effective chemical management decisions, and protect public health.Peer reviewe
Interactive seminars or small group tutorials in preclinical medical education: results of a randomized controlled trial
<p>Abstract</p> <p>Background</p> <p>Learning in small group tutorials is appreciated by students and effective in the acquisition of clinical problem-solving skills but poses financial and resource challenges. Interactive seminars, which accommodate large groups, might be an alternative. This study examines the educational effectiveness of small group tutorials and interactive seminars and students' preferences for and satisfaction with these formats.</p> <p>Methods</p> <p>Students in year three of the Leiden undergraduate medical curriculum, who agreed to participate in a randomized controlled trial (RCT, n = 107), were randomly allocated to small group tutorials (n = 53) or interactive seminars (n = 54). Students who did not agree were free to choose either format (n = 105). Educational effectiveness was measured by comparing the participants' results on the end-of-block test. Data on students' reasons and satisfaction were collected by means of questionnaires. Data was analyzed using student unpaired t test or chi-square test where appropriate.</p> <p>Results</p> <p>There were no significant differences between the two educational formats in students' test grades. Retention of knowledge through active participation was the most frequently cited reason for preferring small group tutorials, while a dislike of compulsory course components was mentioned more frequently by students preferring interactive seminars. Small group tutorials led to greater satisfaction.</p> <p>Conclusions</p> <p>We found that small group tutorials leads to greater satisfaction but not to better learning results. Interactive learning in large groups might be might be an effective alternative to small group tutorials in some cases and be offered as an option.</p
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