Numerical study of neutron beam divergence in a beam-fusion scenario employing laser driven ions

The most established route to create a laser-based neutron source is by employing laser accelerated, low atomic-number ions in fusion reactions. In addition to the high reaction cross-sections at moderate energies of the projectile ions, the anisotropy in neutron emission is another important feature of beam-fusion reactions. Using a simple numerical model based on neutron generation in a pitcher–catcher scenario, anisotropy in neutron emission was studied for the deuterium–deuterium fusion reaction. Simulation results are consistent with the narrow-divergence ( ∼ 70 ° full width at half maximum) neutron beam recently served in an experiment employing multi-MeV deuteron beams of narrow divergence (up to 30° FWHM, depending on the ion energy) accelerated by a sub-petawatt laser pulse from thin deuterated plastic foils via the Target Normal Sheath Acceleration mechanism. By varying the input ion beam parameters, simulations show that a further improvement in the neutron beam directionality (i.e. reduction in the beam divergence) can be obtained by increasing the projectile ion beam temperature and cut-off energy, as expected from interactions employing higher power lasers at upcoming facilities.

Evaluating laser-driven Bremsstrahlung radiation sources for imaging and analysis of nuclear waste packages

A small scale sample nuclear waste package, consisting of a 28 mm diameter uranium penny encased in grout, was imaged by absorption contrast radiography using a single pulse exposure from an X-ray source driven by a high-power laser. The Vulcan laser was used to deliver a focused pulse of photons to a tantalum foil, in order to generate a bright burst of highly penetrating X-rays (with energy >500 keV), with a source size of <0.5 mm. BAS-TR and BAS-SR image plates were used for image capture, alongside a newly developed Thalium doped Caesium Iodide scintillator-based detector coupled to CCD chips. The uranium penny was clearly resolved to sub-mm accuracy over a 30 cm2 scan area from a single shot acquisition. In addition, neutron generation was demonstrated in situ with the X-ray beam, with a single shot, thus demonstrating the potential for multi-modal criticality testing of waste materials. This feasibility study successfully demonstrated non-destructive radiography of encapsulated, high density, nuclear material. With recent developments of high-power laser systems, to 10 Hz operation, a laser-driven multi-modal beamline for waste monitoring applications is envisioned.

Experimental evaluation of the response of micro-channel plate detector to ions with 10s of MeV energies

The absolute calibration of a microchannel plate (MCP) assembly using a Thomson spectrometer for laser-driven ion beams is described. In order to obtain the response of the whole detection system to the particles’ impact, a slotted solid state nuclear track detector (CR-39) was installed in front of the MCP to record the ions simultaneously on both detectors. The response of the MCP (counts/particles) was measured for 5–58 MeV carbon ions and for protons in the energy range2–17.3 MeV. The response of the MCP detector is non-trivial when the stopping range of particles becomes larger than the thickness of the detector. Protons with energiesE>~ 10 MeV are energetic enough that they can pass through the MCP detector. Quantitative analysis of the pits formed in CR-39 and the signal generated in the MCP allowed to determine the MCP response to particles in this energy range. Moreover, a theoretical model allows to predict the response of MCP at even higher proton energies. This suggests that in this regime the MCP response is a slowly decreasing function of energy, consistently with the decrease of the deposited energy. These calibration data will enable particle spectra to be obtained in absolute terms over a broad energy range.

High resolution Thomson Parabola Spectrometer for full spectral capture of multi-species ion beams

We report on the experimental characterisation of laser-driven ion beams using a Thomson Parabola Spectrometer (TPS) equipped with trapezoidally shaped electric plates, proposed by Gwynne et al. [Rev. Sci. Instrum. 85, 033304 (2014)]. While a pair of extended (30 cm long) electric plates was able to produce a significant increase in the separation between neighbouring ion species at high energies, deploying a trapezoidal design circumvented the spectral clipping at the low energy end of the ion spectra. The shape of the electric plate was chosen carefully considering, for the given spectrometer configuration, the range of detectable ion energies and species. Analytical tracing of the ion parabolas matches closely with the experimental data, which suggests a minimal effect of fringe fields on the escaping ions close to the wedged edge of the electrode. The analytical formulae were derived considering the relativistic correction required for the high energy ions to be characterised using such spectrometer.

Recent developments in the Thomson Parabola Spectrometer diagnostic for laser-driven multi-species ion sources

Ongoing developments in laser-driven ion acceleration warrant appropriate modifications to the standard Thomson Parabola Spectrometer (TPS) arrangement in order to match the diagnostic requirements associated to the particular and distinctive properties of laser-accelerated beams. Here we present an overview of recent developments by our group of the TPS diagnostic aimed to enhance the capability of diagnosing multi-species high-energy ion beams. In order to facilitate discrimination between ions with same Z / A , a recursive differential filtering technique was implemented at the TPS detector in order to allow only one of the overlapping ion species to reach the detector, across the entire energy range detectable by the TPS. In order to mitigate the issue of overlapping ion traces towards the higher energy part of the spectrum, an extended, trapezoidal electric plates design was envisaged, followed by its experimental demonstration. The design allows achieving high energy-resolution at high energies without sacrificing the lower energy part of the spectrum. Finally, a novel multi-pinhole TPS design is discussed, that would allow angularly resolved, complete spectral characterization of the high-energy, multi-species ion beams.

Detector for imaging and dosimetry of laser-driven epithermal neutrons by alpha conversion

An epithermal neutron imager based on detecting alpha particles created via boron neutron capture mechanism is discussed. The diagnostic mainly consists of a mm thick Boron Nitride (BN) sheet (as an alpha converter) in contact with a non-borated cellulose nitride film (LR115 type-II) detector. While the BN absorbs the neutrons in the thermal and epithermal ranges, the fast neutrons register insignificantly on the detector due to their low neutron capture and recoil cross-sections. The use of solid-state nuclear track detectors (SSNTD), unlike image plates, micro-channel plates and scintillators, provide safeguard from the x-rays, gamma-rays and electrons. The diagnostic was tested on a proof-of-principle basis, in front of a laser driven source of moderated neutrons, which suggests the potential of using this diagnostic (BN+SSNTD) for dosimetry and imaging applications.

La creación de los profesorados de educación física en Argentina. 1912-2014

El presente trabajo intenta constituir un primer intento de sistematización de algunos antecedentes sobre las creaciones de las propuestas formativas de profesores de educación física en Argentina entre 1912 y 2014. Para ello, a partir del trabajo con diferentes fuentes primarias y secundarias, se desarrollará el devenir de la creación de las distintas propuestas formativas en el ámbito civil en: el ámbito del Ministerio de Educación de la Nación, las Universidades Naciones y los Ministerios de Educación Provinciales. Para ello se inscribirá tales actos, en las tramas locales y de los lineamientos políticos-educativos nacionales y provinciales. Buscando sentar algunas bases para futuros análisis

Making community media work: Community media identities and their articulation in an Antwerp neighbourhood development project

SCOPUS: ch.b

I film therefore I am: process and participation, networks and knowledge – examples from Scottish community media projects.

This chapter examines community media projects in Scotland as social processes that nurture knowledge through participation in production. A visual and media anthropology framework (Ginsburg, 2005) with an emphasis on the social context of media production informs the analysis of community media. Drawing on community media projects in the Govan area of Glasgow and the Isle of Bute, the techniques of production foreground “the relational aspects of filmmaking” (Grimshaw and Ravetz, 2005: 7) and act as a catalyst for knowledge and networks of relations embedded in time and place. Community media is defined here as a creative social process, characterised by an approach to production that is multi-authored, collaborative and informed by the lives of participants, and which recognises the relevance of networks of relations to that practice (Caines, 2007: 2). As a networked process, community media production is recognised as existing in collaboration between a director or producer, such as myself, and organisations, institutions and participants, who are connected through a range of identities, practices and place. These relations born of the production process reflect a complex area of practice and participation that brings together “parallel and overlapping public spheres” (Meadows et al., 2002: 3). This relates to broader concerns with networks (Carpentier, Servaes and Lie, 2003; Rodríguez, 2001), both revealed during the process of production and enhanced by it, and how they can be described with reference to the knowledge practice of community media.

Área de Psicología de la Real Federación Española de Atletismo: programación y desempeño profesional

Desde una amplia trayectoria profesional del psicólogo del deporte dentro del organigrama de los servicios médicos de la Real Federación Española de Atletismo, se presenta la programación y desempeño profesional del Área de Psicología. Los objetivos principales son que los atletas profesionales obtengan su máximo rendimiento deportivo, el logro de objetivos, que las jóvenes promesas lleguen a la élite del atletismo y colaborar con los servicios médicos en materia de lesiones y salud de los deportistas. Las acciones se centran principalmente en la intervención individual con el atleta, la participación en las concentraciones de jóvenes talentos, la asistencia en las competiciones nacionales e internacionales e integración en las sesiones clínicas de los servicios médicos. Se discuten estas cuestiones y se proponen perspectivas futuras de mejora.

Low-Molecular-Weight Fucoidan Induces Endothelial Cell Migration via the PI3K/AKT Pathway and Modulates the Transcription of Genes Involved in Angiogenesis

Low-molecular-weight fucoidan (LMWF) is a sulfated polysaccharide extracted from brown seaweed that presents antithrombotic and pro-angiogenic properties. However, its mechanism of action is not well-characterized. Here, we studied the effects of LMWF on cell signaling and whole genome expression in human umbilical vein endothelial cells and endothelial colony forming cells. We observed that LMWF and vascular endothelial growth factor had synergistic effects on cell signaling, and more interestingly that LMWF by itself, in the absence of other growth factors, was able to trigger the activation of the PI3K/AKT pathway, which plays a crucial role in angiogenesis and vasculogenesis. We also observed that the effects of LMWF on cell migration were PI3K/AKT-dependent and that LMWF modulated the expression of genes involved at different levels of the neovessel formation process, such as cell migration and cytoskeleton organization, cell mobilization and homing. This provides a better understanding of LMWF's mechanism of action and confirms that it could be an interesting therapeutic approach for vascular repair.

Diseño de un modelo de gestión administrativa que incremente la rentabilidad del programa de microcréditos en especie, de la Asociación Agropecuaria Salvadoreña (AGROSAL).

La presente investigación es motivada por el deseo de contribuir al desarrollo de una organización sin fines de lucro que realiza su actividad en el área de microfinanzas, para la reducción de la pobreza en El Salvador. Por ello es una valiosa oportunidad para la aplicación de la teoría administrativa, obtenida durante la formación académica como estudiantes de la Universidad de El Salvador. La investigación tiene como objetivo diseñar un modelo administrativo que incremente la rentabilidad en el proyecto de microcréditos en especie que ejecuta la Asociación Agropecuaria Salvadoreña (AGROSAL). El método utilizado para la realización de la investigación es el deductivo, el cual permite ir de lo general a lo particular, este conduce a la construcción de modelos que representan en forma simplificada la realidad. La aplicación del método fue a través de la encuesta, la observación directa y la revisión de la documentación existente en la organización, tomando en cuenta aspectos fundamentales de modelos de administración y la concepción del microcrédito. Resultado relevante ha sido elaborar el diagnóstico de la situación administrativa y financiera actual de la asociación, que permite proponer los elementos necesarios para estructurar el modelo administrativo de AGROSAL, a través de la aplicación de este modelo se pretende encaminar a la organización hacia la autosostenibilidad institucional y sobretodo amplíe su cobertura de ayuda a más familias salvadoreñas en extrema pobreza. Se recomienda realizar un esfuerzo institucional por implantar los elementos que constituyen el modelo administrativo propuesto, asumiendo nuevos retos que permitan el aprovechamiento de las áreas de oportunidad.

Validity of the physical activity questionnaires IPAQ-SF and GPAQ for Cancer Survivors: Insights from a Spanish cohort

Regular physical activity (PA) decreases mortality risk in survivors of breast and colorectal cancer. Such impacts of exercise have prompted initiatives designed both to promote and adequately monitor PA in cancer survivors. This study examines the validity of 2 widely used self-report methods for PA determination, the International Physical Activity Questionnaire short version (IPAQ-SF) and Global Physical Activity Questionnaire (GPAQ). Both instruments were compared with the triaxial accelerometry (Actigraph) method as an objective reference standard. Study participants were 204 cancer survivors (both sexes, aged 18-79 years). Compared with accelerometry, both questionnaires significantly overestimated PA levels (across all intensities) and underestimated physical inactivity levels. No differences were detected between the 2 questionnaires except for a shorter inactivity time estimated by GPAQ (p=0.001). The Bland and Altman method confirmed that both questionnaires overestimated all PA levels. Receiver operating characteristic (ROC) analysis classified IPAQ and GPAQ as fair and poor predictors, respectively, of the proportions of survivors fulfilling international PA recommendations (≥150 min·week-1 of moderate-vigorous PA). IPAQ-SF showed a higher sensitivity but lower specificity than GPAQ. Our data do not support the use of IPAQ-SF or GPAQ to determine PA or inactivity levels in cancer survivors.

Índice del perfil del donante renal (KDPI) como factor pronóstico del trasplante

La enfermedad renal crónica ha aumentado a nivel mundial y nacional, mientras que el número de donantes viene en descenso, y los pacientes en lista de espera aumentan. Los donantes cadavéricos son una opción para estos pacientes, y han sido utilizados en últimos años para aumentar los órganos disponibles. La evaluación de la calidad de estos es importante para optimizar su uso. Estudio analítico tipo cohorte retrospectiva, cálculo de KDPI en donantes cadavéricos, seguimiento función renal creatinina sérica 1 mes, 3 meses, 6 meses y un año. Correlación supervivencia del injerto, función renal, KDPI y EPTS. Análisis de supervivencia y regresión logística con variables del donante, receptor y acto quirúrgico.