A flexible luminescent probe to monitor fast ion losses at the edge of the TJ-II stellarator

A mobile luminescent probe has been developed to detect fast ion losses and suprathermal ions escaping from the plasma of the TJ-II stellarator device. The priorities for its design have been flexibility for probe positioning, ease of maintenance, and detector sensitivity. It employs a coherent fiber bundle to relay, to the outside of the vacuum chamber, ionoluminescence images produced by the ions that impinge, after entering the detector head through a pinhole aperture, onto a screen of luminescent material. Ionoluminescence light detection is accomplished by a charge-coupled device camera and by a photomultiplier, both of which are optically coupled to the in-vacuum fiber bundle head by means of a standard optical setup. A detailed description of the detector, and the first results obtained when operated close to the plasma edge, are reported.Ministerio de Educación y Ciencia FTN 2003-0905, ENE2007-6500

Social cooperation and resource management dynamics among late hunter-fisher-gatherer societies in Tierra del Fuego (South America)

This paper presents the theoretical basis and first results of an agent-based model (ABM) computer simulation that is being developed to explore cooperation in hunter–gatherer societies. Specifically, we focus here on Yamana, a hunter-fisher-gatherer society that inhabited the islands of the southernmost part of Tierra del Fuego (Argentina–Chile). Ethnographical and archaeological evidence suggests the existence of sporadic aggregation events, triggered by a public call through smoke signals of an extraordinary confluence of resources under unforeseeable circumstances in time and space (a beached whale or an exceptional accumulation of fish after a low tide, for example). During these aggregation events, the different social units involved used to develop and improve production, distribution and consumption processes in a collective way. This paper attempts to analyse the social dynamics that explain cooperative behaviour and resource-sharing during aggregation events using an agent-based model of indirect reciprocity. In brief, agents make their decisions based on the success of the public strategies of other agents. Fitness depends on the resource captured and the social capital exchanged in aggregation events, modified by the agent’s reputation. Our computational results identify the relative importance of resources with respect to social benefits and the ease in detecting—and hence punishing—a defector as key factors to promote and sustain cooperative behaviour among populationSpanish Ministerio de Ciencia e Innovación (projects CONSOLIDER-INGENIO 2010 SimulPast-CSD2010-00034 and HAR2009-06996) as well as from the Argentine Consejo Nacional de Investigaciones Científicas y Técnicas (project PIP-0706) and the Wenner-Gren Foundation for Anthropological Research (project GR7846)

Ionoluminescent response of several phosphor screens to keV ions of different masses

We have characterized the ionoluminescent response of several phosphor powder materials when irradiated with ions of different masses H+ ,He+ ,Ar+ accelerated to keV energies. In particular, we have determined the absolute luminosity in terms of the number of photons per incident ion emitted by luminescent screens of Y2O2S:Tb P45, Y3Al5O12 :Ce P46, Y2SiO5 :Ce P47, Y2O3 :Eu P56, and SrGa2S4 :Eu TG-green. Their ionoluminescence has been studied as a function of ion beam energy and current and ion fluency. The energy trend and mass dependence of selected experimental results are compared relative to stopping and range of ions in matter SRIM code predictions.Ministerio de Educación y Ciencia FTN2003-090

Study of the neoclassical radial electric field of the TJ-II flexible heliac

Calculations of the monoenergetic radial diffusion coefficients are presented for several configurations of the TJ-II stellarator usually explored in operation. The neoclassical radial fluxes and the ambipolar electric field for the standard configuration are then studied for three different collisionality regimes, obtaining precise results in all cases

Profile and professional expectations of medical students from 11 Latin American countries: the Red-LIRHUS project

Background Latin America is undergoing a human resource crisis in health care in terms of labor shortage, misdistribution and poor orientation to primary care. Workforce data are needed to inform the planning of long-term strategies to address this problem. This study aimed to evaluate the academic and motivational profile, as well as the professional expectations, of Latin American medical students. Results We conducted an observational, cross-sectional, multi-country study evaluating medical students from 11 Spanish-speaking countries in 2011–2012. Motivations to study medicine, migration intentions, intent to enter postgraduate programs, and perceptions regarding primary care were evaluated via a self-administered questionnaire. Outcomes were measured with pilot-tested questions and previously validated scales. A total of 11,072 valid surveys from 63 medical schools were gathered and analyzed. Conclusions This study describes the profile and expectations of the future workforce being trained in Latin America. The obtained information will be useful for governments and universities in planning strategies to improve their current state of affairs regarding human resources for health care professions

At the coalface and the cutting edge: general practitioners’ accounts of the rewards of engaging with HIV medicine

The interviews we conducted with GPs suggest that an engagement with HIV medicine enables clinicians to develop strong and long-term relationships with and expertise about the care needs of people living with HIV ‘at the coalface’, while also feeling connected with a broader network of medical practitioners and other professionals concerned with and contributing to the ever-changing world of science: ‘the cutting edge’. The general practice HIV prescriber is being modelled here as the interface between these two worlds, offering a rewarding opportunity for general practitioners to feel intimately connected to both community needs and scientific change

Overview of recent TJ-II stellarator results

The main results obtained in the TJ-II stellarator in the last two years are reported. The most important topics investigated have been modelling and validation of impurity transport, validation of gyrokinetic simulations, turbulence characterisation, effect of magnetic configuration on transport, fuelling with pellet injection, fast particles and liquid metal plasma facing components. As regards impurity transport research, a number of working lines exploring several recently discovered effects have been developed: the effect of tangential drifts on stellarator neoclassical transport, the impurity flux driven by electric fields tangent to magnetic surfaces and attempts of experimental validation with Doppler reflectometry of the variation of the radial electric field on the flux surface. Concerning gyrokinetic simulations, two validation activities have been performed, the comparison with measurements of zonal flow relaxation in pellet-induced fast transients and the comparison with experimental poloidal variation of fluctuations amplitude. The impact of radial electric fields on turbulence spreading in the edge and scrape-off layer has been also experimentally characterized using a 2D Langmuir probe array. Another remarkable piece of work has been the investigation of the radial propagation of small temperature perturbations using transfer entropy. Research on the physics and modelling of plasma core fuelling with pellet and tracer-encapsulated solid-pellet injection has produced also relevant results. Neutral beam injection driven Alfvénic activity and its possible control by electron cyclotron current drive has been examined as well in TJ-II. Finally, recent results on alternative plasma facing components based on liquid metals are also presented. ISSN:0029-5515 ISSN:1741-432