Numerical studies of disruptions in tokamaks

Imperial Users onl

A Study of the Relation of Buildings and Equipment to the Teaching Process in the Children\u27s Division

The Sunday school has come a long way in its comparatively short history. It has come a long way both in philosophy and housing. Because it is an organism of living persons, it has grown, developed, expanded, changed. With the passing of the years, there has been growing a greater reverence for the unfolding personality of the learning person. As a consequence, the pupil has come more and more to the forefront. Less attempt is being Fade to impose arbitrary teaching procedures as well as the content of a fixed curriculum upon the learner. A greater effort is being made to find out what actually affects and captures the interests and changes the attitudes and the life of the person who is being exposed to religious teaching. This constant search for and emphasis upon the importance and sacredness of human personality, has led educators to ask humbly, What sort of building, what teaching methods best serve in shaping Christian personality at each and every stage of development

Feedback Enhanced Sensitivity in Optomechanics: Surpassing the Parametric Instability Barrier

The intracavity power, and hence sensitivity, of optomechanical sensors is commonly limited by parametric instability. Here we characterize the parametric instability induced sensitivity degradation in a micron scale cavity optomechanical system. Feedback via optomechanical transduction and electrical gradient force actuation is applied to suppress the parametric instability. As a result a 5.4 fold increase in mechanical motion transduction sensitivity is achieved to a final value of $1.9\times 10^{-18}\rm m Hz^{-1/2}$.Comment: 4 pages, 4 figure

Minimum requirements for feedback enhanced force sensing

The problem of estimating an unknown force driving a linear oscillator is revisited. When using linear measurement, feedback is often cited as a mechanism to enhance bandwidth or sensitivity. We show that as long as the oscillator dynamics are known, there exists a real-time estimation strategy that reproduces the same measurement record as any arbitrary feedback protocol. Consequently some form of nonlinearity is required to gain any advantage beyond estimation alone. This result holds true in both quantum and classical systems, with non-stationary forces and feedback, and in the general case of non-Gaussian and correlated noise. Recently, feedback enhanced incoherent force sensing has been demonstrated [Nat. Nano. \textbf{7}, 509 (2012)], with the enhancement attributed to a feedback induced modification of the mechanical susceptibility. As a proof-of-principle we experimentally reproduce this result through straightforward filtering.Comment: 5 pages + 2 pages of Supplementary Informatio

Réexamen de la proposition de valeur de la formation médicale axée sur les compétences

The adoption of competency-based medical education (CBME) by Canadian postgraduate training programs has created a storm of excitement and controversy. Implementing the system-wide Competency by Design (CBD) project initiated by the Royal College of Physicians & Surgeons of Canada (RCPSC), is an ambitious transformative change challenge. Not surprisingly, tensions have arisen across the country around the theoretical underpinnings of CBME and the practicalities of implementation, resulting in calls for evidence justifying its value. Assumptions have been made on both sides of the argument contributing to an atmosphere of unhealthy protection of the status quo, premature conclusions of CBME’s worth, and an oversimplification of risks and costs to participants. We feel that a renewed effort to find a shared vision of medical education and the true value proposition of CBME is required to recreate a growth-oriented mindset. Also, the aspirational assertion of a direct link between CBME and improved patient outcomes requires deferral until further implementation and study has occurred. However, we perceive more concrete and immediate value of CBME arises from the societal contract physicians have, the connection to maintaining self-regulation, and the potential customization of training for learners.L’adoption de la formation médicale axée sur les compétences (FMAC) dans les programmes canadiens d’études postdoctorales a suscité une tempête d’enthousiasme et de controverse. La mise en œuvre à l’échelle du système du projet Compétence par conception (CPC), lancé par le Collège royal des médecins et chirurgiens du Canada (CRMCC), pose le défi d’un changement ambitieux et transformateur. Il n’est pas surprenant que des tensions soient apparues dans tout le pays autour des fondements théoriques de la FMAC et des aspects pratiques de sa mise en œuvre, donnant lieu à des demandes de preuves pour démontrer sa valeur.1 Détracteurs et partisans ont avancé des suppositions, contribuant à un climat malsain de protection du statu quo, à des conclusions prématurées sur la valeur de la FMAC et à une simplification exagérée des risques et des coûts pour les participants. Nous estimons qu’un effort pour retrouver une vision commune de l’éducation médicale et une proposition sérieuse quant à la valeur de la FMAC sont de mise afin de restaurer une attitude orientée vers l’avancement. De plus, il conviendrait de s’abstenir d’affirmer l’existence d’un lien direct entre la FMAC et l’amélioration des résultats pour les patients en attendant qu’une mise en oeuvre plus étendue et que de la recherche plus approfondie aient eu lieu. Cependant, on peut observer dans la FMAC une valeur concrète et immédiate découlant de la présence d’un engagement des médecins envers la société, de son orientation vers le maintien de l’autorégulation et de la personnalisation potentielle de la formation pour les apprenants

The Gears of Childhood

Over the years, Logo and turtle geometry provided a rather durable transitional object. When Logo first experienced tremendous popularity, there arose a debate as to whether Logo was the only valid transitional object that could exist on the computer. This might be termed the phase of Logo as Religion

Thin film superfluid optomechanics

Excitations in superfluid helium represent attractive mechanical degrees of freedom for cavity optomechanics schemes. Here we numerically and analytically investigate the properties of optomechanical resonators formed by thin films of superfluid $^4$He covering micrometer-scale whispering gallery mode cavities. We predict that through proper optimization of the interaction between film and optical field, large optomechanical coupling rates $g_0>2\pi \times 100$ kHz and single photon cooperativities $C_0>10$ are achievable. Our analytical model reveals the unconventional behaviour of these thin films, such as thicker and heavier films exhibiting smaller effective mass and larger zero point motion. The optomechanical system outlined here provides access to unusual regimes such as $g_0>\Omega_M$ and opens the prospect of laser cooling a liquid into its quantum ground state.Comment: 18 pages, 6 figure

Cardiovascular collapse caused by carbon dioxide insufflation during one-lung anaesthesia for thoracoscopic dorsal sympathectomy

Publisher's copy made available with the permission of the publisherCarbon dioxide insufflation into the pleural space during one-lung anaesthesia for thoracoscopic surgery is used in some centres to improve surgical access, even though this practice has been associated with well-described cardiovascular compromise. The present report is of a 35-year-old woman undergoing thoracoscopic left dorsal sympathectomy for hyperhidrosis. During one-lung anaesthesia the insufflation of carbon dioxide into the non-ventilated hemithorax for approximately 60 seconds, using a pressure-limited gas inflow, was accompanied by profound bradycardia and hypotension that resolved promptly with the release of the gas. Possible mechanisms for the cardiovascular collapse are discussed, and the role of carbon dioxide insufflation as a means of expediting lung collapse for procedures performed using single-lung ventilation is questioned.RJD Harris, G Benveniste, J Pfitznerhttp://www.aaic.net.au/Article.asp?D=200119

Modelling of vorticity, sound and their interaction in two-dimensional superfluids

Vorticity in two-dimensional superfluids is subject to intense research efforts due to its role in quantum turbulence, dissipation and the BKT phase transition. Interaction of sound and vortices is of broad importance in Bose-Einstein condensates and superfluid helium [1-4]. However, both the modelling of the vortex flow field and of its interaction with sound are complicated hydrodynamic problems, with analytic solutions only available in special cases. In this work, we develop methods to compute both the vortex and sound flow fields in an arbitrary two-dimensional domain. Further, we analyse the dispersive interaction of vortices with sound modes in a two-dimensional superfluid and develop a model that quantifies this interaction for any vortex distribution on any two-dimensional bounded domain, possibly non-simply connected, exploiting analogies with fluid dynamics of an ideal gas and electrostatics. As an example application we use this technique to propose an experiment that should be able to unambiguously detect single circulation quanta in a helium thin film.Comment: 23 pages, 8 figure