Investigation of the relevant kinetic processes in the initial stage of a double-arcing instability in oxygen plasmas

A numerical investigation of the kinetic processes in the initial (nanosecond range) stage of the double-arcing instability was developed. The plasma-sheath boundary region of an oxygen-operated cutting torch was considered. The energy balance and chemistry processes in the discharge were described. It is shown that the double-arcing instability is a sudden transition from a diffuse (glow-like) discharge to a constricted (arc-like) discharge in the plasma-sheath boundary region arising from a field-emission instability. A critical electric field value of ∼10^7 V/m was found at the cathodic part of the nozzle wall under the conditions considered. The field-emission instability drives in turn a fast electronic-to-translational energy relaxation mechanism, giving rise to a very fast gas heating rate of at least ∼10^9 K/s, mainly due to reactions of preliminary dissociation of oxygen molecules via the highly excited electronic state O2(B^3) populated by electron impact. It is expected that this fast oxygen heating rate further stimulates the discharge contraction through the thermal instability mechanism.Fil: Mancinelli, Beatriz Rosa. Universidad Tecnológica Nacional. Facultad Regional Venado Tuerto; ArgentinaFil: Prevosto, Leandro. Universidad Tecnológica Nacional. Facultad Regional Venado Tuerto; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Chamorro Garcés, Juan Camilo. Universidad Tecnológica Nacional. Facultad Regional Venado Tuerto; ArgentinaFil: Minotti, Fernando Oscar. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Kelly, Hector Juan. Universidad Tecnológica Nacional. Facultad Regional Venado Tuerto; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentin

How useful are post consultation letters to patients?

BACKGROUND: As part of the NHS plan it was suggested that all patients receive copies of letters sent to their General Practitioner following outpatient consultations. The former Secretary of State for Health extended this proposal, suggesting that patients have a specific letter to themselves after a hospital consultation. METHODS: The aim of this study was to send cardiorespiratory patients attending Charing Cross Hospital, a copy of the letter sent to their G.P. plus a specific letter to themselves and to assess the usefulness and comprehensibility of each. The letters were analysed for dictation time, Flesch Reading Ease Score, Flesch-Kincaid Grade Level and word count. Eighty-four out of 105 sequential patients (80%) consented and were sent both types of letter after their attendance. Patients returned both letters circling any items they did not understand and stated a preference for the GP letter, patient letter, or both. The patients' GPs were subsequently also asked for their views on each letter. RESULTS: GP letters took significantly longer to dictate than patient letters. The Flesch Reading Ease Score was significantly higher in the patient letters, indicating that the patient letters were easier to read. The GP letters were significantly longer than the patient letters and patients were significantly more likely to circle more items in the GP letters (p < 0.001). The content of letters is sometimes inaccurate. Thirty-six out of 62 patients (58%) would like to receive both letters, 13/62 (21.6%) would prefer the GP letter and 13/62 (20%) wanted only the patient letter. 45 GPs replied (62.5%), 28/45 (62.5%) wanted the GP letter, 14 GPs (31.1%) wanted both letters and 3/45 (6.7%) wanted the patient letter only. General themes concerned insufficient clinical details and the GPs preferred the structure of the letters written to them. CONCLUSION: Patients appreciate copies of the letter being sent to their GP but comprehension is less good than with a shorter letter written especially to the patient. More attention needs to be paid to making letters to GPs simpler to read without losing the structure and detail liked by GPs. A compromise might be to dictate the letter in front of the patient and to provide a speciality-specific glossary to accompany each letter

The perceived impact of location privacy: A web-based survey of public health perspectives and requirements in the UK and Canada

<p>Abstract</p> <p>Background</p> <p>The "place-consciousness" of public health professionals is on the rise as spatial analyses and Geographic Information Systems (GIS) are rapidly becoming key components of their toolbox. However, "place" is most useful at its most precise, granular scale – which increases identification risks, thereby clashing with privacy issues. This paper describes the views and requirements of public health professionals in Canada and the UK on privacy issues and spatial data, as collected through a web-based survey.</p> <p>Methods</p> <p>Perceptions on the impact of privacy were collected through a web-based survey administered between November 2006 and January 2007. The survey targeted government, non-government and academic GIS labs and research groups involved in public health, as well as public health units (Canada), ministries, and observatories (UK). Potential participants were invited to participate through personally addressed, standardised emails.</p> <p>Results</p> <p>Of 112 invitees in Canada and 75 in the UK, 66 and 28 participated in the survey, respectively. The completion proportion for Canada was 91%, and 86% for the UK. No response differences were observed between the two countries. Ninety three percent of participants indicated a requirement for personally identifiable data (PID) in their public health activities, including geographic information. Privacy was identified as an obstacle to public health practice by 71% of respondents. The overall self-rated median score for knowledge of privacy legislation and policies was 7 out of 10. Those who rated their knowledge of privacy as high (at the median or above) also rated it significantly more severe as an obstacle to research (<it>P </it>< 0.001). The most critical cause cited by participants in both countries was bureaucracy.</p> <p>Conclusion</p> <p>The clash between PID requirements – including granular geography – and limitations imposed by privacy and its associated bureaucracy require immediate attention and solutions, particularly given the increasing utilisation of GIS in public health. Solutions include harmonization of privacy legislation with public health requirements, bureaucratic simplification, increased multidisciplinary discourse, education, and development of toolsets, algorithms and guidelines for using and reporting on disaggregate data.</p

Does peer learning or higher levels of e-learning improve learning abilities? A randomized controlled trial

Background and aims : The fast development of e-learning and social forums demands us to update our understanding of e-learning and peer learning. We aimed to investigate if higher, pre-defined levels of e-learning or social interaction in web forums improved students&#x2019; learning ability. Methods : One hundred and twenty Danish medical students were randomized to six groups all with 20 students (eCases level 1, eCases level 2, eCases level 2+, eTextbook level 1, eTextbook level 2, and eTextbook level 2+). All students participated in a pre-test, Group 1 participated in an interactive case-based e-learning program, while Group 2 was presented with textbook material electronically. The 2+ groups were able to discuss the material between themselves in a web forum. The subject was head injury and associated treatment and observation guidelines in the emergency room. Following the e-learning, all students completed a post-test. Pre- and post-tests both consisted of 25 questions randomly chosen from a pool of 50 different questions. Results : All students concluded the study with comparable pre-test results. Students at Level 2 (in both groups) improved statistically significant compared to students at level 1 (p&#x003E;0.05). There was no statistically significant difference between level 2 and level 2+. However, level 2+ was associated with statistically significant greater student&#x0027;s satisfaction than the rest of the students (p&#x003E;0.05). Conclusions : This study applies a new way of comparing different types of e-learning using a pre-defined level division and the possibility of peer learning. Our findings show that higher levels of e-learning does in fact provide better results when compared with the same type of e-learning at lower levels. While social interaction in web forums increase student satisfaction, learning ability does not seem to change. Both findings are relevant when designing new e-learning materials

Internet-based medical education: a realist review of what works, for whom and in what circumstances

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