Fast Response Scintillator Based Detector for MHD Induced Energetic Ion Losses in ASDEX Upgrade

In fusion plasma devices, fast particles i.e. suprathermal ions generated by heating systems and fusion born a particles must be well confined, until they have transferred their energy to the plasma bulk. Signicant loss of these ions may reduce drastically the heating eficiency and, in addition, may cause damage to plasma facing components in the vacuum vessel, if it is suficiently intense and localized. A detailed knowledge of the underlying physics in particular in the presence of magnetohydrodynamic (MHD) instabilities is of crucial importance, since these instabilities can lead to an enhancement of the outwards fast ion radial drift. The development of a new diagnostic for the study of fast particle-wave interactions in the ASDEX Upgrade tokamak as well as the interpretation of the rst measurements have been the aim of this thesis. The design is based on similar diagnostics that have been operated in the TFTR tokamak and the W7-AS stellerator. The fast ion loss detector acts as a magnetic spectrometer, dispersing fast ions onto a scintillator, with the strike point depending on their gyroradius (energy) and pitch angle (angle between ion velocity and magnetic eld line). The emitted light pattern allows particle identification in the phase space with a high time resolution. The major new development for the diagnostic used on ASDEX Upgrade is the use of a very fast scintillator material that allows sampling rates up to 1 MHz, adequate to study time resolved interactions between MHD modes and fast particles. Fast Ion Losses (FIL) were found in the presence of different kinds of MHD instabilities: time resolved FIL due to Edge Localized Modes (ELMs) have been directly observed. They show a complex behavior of a great variety, depending on the ELM substructure. The influence of ELMs on escaping fast particles is appreciable in the whole lost particle phase space independent of the fast ion source. FIL could be measured in the presence of Toroidal Alfv´en Eigenmodes (TAEs) in ICRH heated discharges. Both species, fast hydrogen and deuterium ions are affected in a similar way by TAEs. A resonant process between the TAE frequency and the precession frequency of the lost ions has been identied by comparisons with HAGIS simulations as the loss mechanism. A new MHD perturbation has been observed for the first time during this thesis by means of its strong influence on the energetic deuterium ion population. The mode is localized deeply in the plasma core and dominates the uxes of lost fast deuterium ions in ICRH heated discharges. Finally, bursts of fast deuterium ions ejected by Neoclassical Tearing Modes have been detected in discharges with different heating systems. In pure NBI heated discharges, these ions have energies approximately equal to the full NBI injection energy and pitch angles corresponding to ions on passing orbits. A detailed study of the FIL signal together with Mirnov coil signals revealed that the losses are due to a diffusive process. According to this, simulations with the ORBIT code have proven that orbit stochasticity is a good candidate for the mechanism that causes the losses of these, in principle well confined, passing ions. These results revealed the high diagnostic potential of this method, opening new ways towards a better understanding of the fast ion physics and therefore will help to predict the behavior of fast ions in the presence of MHD instabilities for ITER

Nonlinear alfv\'enic fast particle transport and losses

Magnetohydrodynamic instabilities like Toroidal Alfv\'en Eigenmodes or core-localized modes such as Beta Induced Alfv\'en Eigenmodes and Reversed Shear Alfv\'en Eigenmodes driven by fast particles can lead to significant redistribution and losses in fusion devices. This is observed in many ASDEX Upgrade discharges. The present work aims to understand the underlying resonance mechanisms, especially in the presence of multiple modes with different frequencies. Resonant mode coupling mechanisms are investigated using the drift kinetic HAGIS code [Pinches 1998]. Simulations were performed for different plasma equilibria, in particular for different q profiles, employing the availability of improved experimental data. A study was carried out, investigating double-resonant mode coupling with respect to various overlapping scenarios. It was found that, depending on the radial mode distance, double-resonance is able to enhance growth rates as well as mode amplitudes significantly. Small radial mode distances, however can also lead to strong nonlinear mode stabilization of a linear dominant mode. With the extended version of HAGIS, losses were simulated and directly compared with experimental loss measurements. The losses' phase space distribution as well as their ejection signal is consistent with experimental data. Furthermore, it allowed to characterize them as prompt, resonant or stochastic. It was found that especially in multiple mode scenarios (with different mode frequencies), abundant incoherent losses occur in the lower energy range, due to a broad phase-space stochastization. The incoherent higher energetic losses are "prompt", i.e. their initial energy is too large for confined orbits.Comment: 7 pages, 6 figures, Reviewed Conference Proceedings (Joint Varenna - Lausanne International Workshop on the Theory of Fusion Plasmas) to be published in IOP's "Journal of Physics: Conference Series

Does student proactivity guarantee positive academic results?

This paper analyzes the impact of students’ proactivity on academic performance based on a sample from students enrolled in an introductory course of Political Economy at the University of Seville (Spain) in three consecutive courses (2014–2015, 2015–2016 and 2016–2017). Proactivity is measured by several indicators, such as class attendance, case-study oral presentation and its delivery in a foreign language, all of them being non-mandatory activities for students who have participated in the experiment. Specifically, this study aims to assess the impact of a student’s proactivity on two academic outcomes: (i) to pass or fail the exam; and (ii) the score obtained. Impact assessment has been performed using a probit and ordered multinomial logit models. The results show that a student’s proactivity measured by class attendance and case-study presentation significantly increases the probability of passing the exam, while the impact of using a foreign language seems to be non-significant. In relation to the score obtained, the proactivity measured through the case presentation raises the probability of obtaining a higher mark more than regular class attendance.Junta de Andalucía proyecto SEJ-132Universidad Autónoma de ChileUniversidad de Sevilla. Departamento de Análisis Económico y Política Económic

Energetic particle acceleration and transport by Alfven/acoustic waves in tokamak-like Solar flares

Alfv´en/acoustic waves are ubiquitous in astrophysical as well as in laboratory plasmas. Their interplay with energetic ions is of crucial importance to understanding the energy and particle exchange in astrophysical plasmas as well as to obtaining a viable energy source in magnetically confined fusion devices. In magnetically confined fusion plasmas, an experimental phase-space characterisation of convective and diffusive energetic particle losses induced by Alfv´en/acoustic waves allows for a better understanding of the underlying physics. The relevance of these results in the problem of the anomalous heating of the solar corona is checked by MHD simulations of Tokamak-like Solar flare tubes

Education and sport: relationships, construction and mutual influence

Realizar un análisis y reflexión sobre las relaciones existentes entre educación y deporte, a priori puede parecer una tarea sencilla o fácil, bien porque vivimos en una sociedad en la que se pone de manifiesto el deporte en todas sus dimensiones: cultural, económica, política…; o bien porque el deporte está presente en multitud de actos de nuestra vida cotidiana: ocio, recreación, espectáculo…Pero mucho más lejos de la realidad, se presenta como una tarea ardua, difícil y complicada. Por ello, con este artículo pretendemos profundizar un poco más sobre dichos conceptos y sus relaciones, planteándonos una serie de interrogantes que en principio pueden pasar desapercibidos; pero para nosotros, como docentes de la Educación Física -área curricular que tiene como campo de conocimiento ambos constructos-, hace que replanteemos ciertos planteamientos didácticos. Estas inquietudes nos han llevado a revisar el marco teórico conceptual sobre las relaciones existentes entre educación y deporte; puesto que, sí comulgamos con la filosofía de que el deporte es un fenómeno que está presente en la sociedad, que hay que trabajarlo, enseñarlo y favorecerlo desde las instituciones educativas… La Educación Física es el área idónea para desarrollar este trabajo, favoreciendo así el hecho de considerar el deporte como una actividad fundamental en el desarrollo integral y formación académica de los alumnos durante su etapa escolar.The fact of carrying out an analysis, and a reflection about the relationships between education and sports could be considered as a simple or easy task; either because we live in a society, in which sport is exposed in every its dimensions: cultural, economic, political...; or given the fact that sport is presented in a large group of our lives’ actions: free time, recreation, performance... However, far from the reality, it is displayed as arduous, difficult and complex task. Therefore, this article expects to delve more into those concepts and their connections, considering a series of questions that at the beginning can be seen unnoticed; but for the authors, as teachers of Physical Education – curricular area which is the field of knowledge of both of them – , makes them reflect again certain didactic proposals. These concerns make the writers revise the conceptual theoretical framework about the relationships between education and sport; given that, if they agree on the philosophy that sport is a phenomenon presented in society, which has to be worked, taught and assist it from the educational institutions... Physical Education is the ideal area to develop this work, that way supporting the fact of considering sport as a fundamental activity in the integral development, and the academic education of students during their school years

Involvement of PGE2 and cyclic AMP signaling pathway in the up-regulation of COX-2and mPGES-1 expression in LPS -activated macrophages

The final version of record is available at /http://www.biochemj.org/bj

Recent ASDEX Upgrade research in support of ITER and DEMO

Recent experiments on the ASDEX Upgrade tokamak aim at improving the physics base for ITER and DEMO to aid the machine design and prepare efficient operation. Type I edge localized mode (ELM) mitigation using resonant magnetic perturbations (RMPs) has been shown at low pedestal collisionality ( ν ∗ ped < 0 . 4 ) . In contrast to the previous high ν ∗ regime, suppression only occurs in a narrow RMP spectral window, indicating a resonant process, and a concomitant confinement drop is observed due to a reduction of pedestal top density and electron temperature. Strong evidence is found for the ion heat flux to be the decisive element for the L–H power threshold. A physics based scaling of the density at which the minimum P LH occurs indicates that ITER could take advantage of it to initiate H-mode at lower density than that of the final Q = 10 operational point. Core density fluctuation measurements resolved in radius and wave number show that an increase of R/L T e introduced by off-axis electron cyclotron resonance heating (ECRH) mainly increases the large scale fluctuations. The radial variation of the fluctuation level is in agreement with simulations using the GENE code. Fast particles are shown to undergo classical slowing down in the absence of large scale magnetohydrodynamic (MHD) events and for low heating power, but show signs of anomalous radial redistribution at large heating power, consistent with a broadened off-axis neutral beam current drive current profile under these conditions. Neoclassical tearing mode (NTM) suppression experiments using electron cyclotron current drive (ECCD) with feedback controlled deposition have allowed to test several control strategies for ITER, including automated control of (3,2) and (2,1) NTMs during a single discharge. Disruption mitigation studies using massive gas injection (MGI) can show an increased fuelling efficiency with high field side injection, but a saturation of the fuelling efficiency is observed at high injected mass as needed for runaway electron suppression. Large locked modes can significantly decrease the fuelling efficiency and increase the asymmetry of radiated power during MGI mitigation. Concerning power exhaust, the partially detached ITER divertor scenario has been demonstrated at P sep /R = 10 MW m − 1 in ASDEX Upgrade, with a peak time averaged target load around 5MWm − 2 , well consistent with the component limits for ITER. Developing this towards DEMO, full detachment was achieved at P sep /R = 7MWm − 1 and stationary discharges with core radiation fraction of the order of DEMO requirements (70% instead of the 30% needed for ITER) were demonstrated. Finally, it remains difficult to establish the standard ITER Q = 10 scenario at low q 95 = 3 in the all-tungsten (all-W) ASDEX Upgrade due to the observed poor confinement at low β N . This is mainly due to a degraded pedestal performance and hence investigations at shifting the operational point to higher β N by lowering the current have been started. At higher q 95 , pedestal performance can be recovered by seeding N 2 as well as CD 4 , which is interpreted as improved pedestal stability due to the decrease of bootstrap current with increasing Z eff . Concerning advanced scenarios, the upgrade of ECRH power has allowed experiments with central ctr-ECCD to modify the q -profile in improved H-mode scenarios, showing an increase in confinement at still good MHD stability with flat elevated q -profiles at values between 1.5 and 2.European Commission (EUROfusion 633053

Nutrients and Dietary Patterns Related to Osteoporosis

Osteoporosis is a common chronic disease characterized by a decrease in bone mineral density, impaired bone strength, and an increased risk of fragility fractures. Fragility fractures are associated with significant morbidity, mortality and disability and are a major public health problem worldwide. The influence of nutritional factors on the development and progression of this disease can be significant and is not yet well established. Calcium intake and vitamin D status are considered to be essential for bone metabolism homeostasis. However, some recent studies have questioned the usefulness of calcium and vitamin D supplements in decreasing the risk of fractures. The adequate intake of protein, vegetables and other nutrients is also of interest, and recommendations have been established by expert consensus and clinical practice guidelines. It is important to understand the influence of nutrients not only in isolation but also in the context of a dietary pattern, which is a complex mixture of nutrients. In this review, we evaluate the available scientific evidence for the effects of the main dietary patterns on bone health. Although some dietary patterns seem to have beneficial effects, more studies are needed to fully elucidate the true influence of diet on bone fragility.Instituto de Salud Carlos III PI18/01235European Union (EU

Vitamin D Status, Calcium Intake and Risk of Developing Type 2 Diabetes: An Unresolved Issue

The relationship between vitamin D status, calcium intake and the risk of developing type 2 diabetes (T2D) is a topic of growing interest. One of the most interesting non-skeletal functions of vitamin D is its potential role in glucose homeostasis. This possible association is related to the secretion of insulin by pancreatic beta cells, insulin resistance in different tissues and its influence on systemic inflammation. However, despite multiple observational studies and several meta-analyses that have shown a positive association between circulating 25-hydroxyvitamin D concentrations and the risk of T2D, no randomized clinical trials supplementing with different doses of vitamin D have confirmed this hypothesis definitively. An important question is the identification of what 25-hydroxyvitamin D levels are necessary to influence glycemic homeostasis and the risk of developing T2D. These values of vitamin D can be significantly higher than vitamin D levels required for bone health, but the currently available data do not allow us to answer this question adequately. Furthermore, a large number of observational studies show that dairy consumption is linked to a lower risk of T2D, but the components responsible for this relationship are not well established. Therefore, the importance of calcium intake in the risk of developing T2D has not yet been established. Although there is a biological plausibility linking the status of vitamin D and calcium intake with the risk of T2D, well-designed randomized clinical trials are necessary to answer this important question

Transferencias redistributivas en metálico y en especie: una síntesis.

Although the traditional argument states that transfers should always be made in cash, based on the idea of the consumer’s absolute sovereignty; in an imperfect world, there are many reasonings which are clearly in favor of in-kind transfers (egalitarianism in term of goods, paternalism, externalities, Second-Best scenarios, effects on the incentive to work, “The Samaritan’s dilemma”, pecuniary effects, social insurance, transmission of individual values, political considerations, or inflation). In this paper we review all these theoretical arguments given in the literature to justify that public transfers are carried out in cash or in kind. In addition, we outline the most relevant empirical studies.Public expenditure, cash transfers, in-kind transfers, efficiency, equity.