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

Isotemporal substitution of inactive time with physical activity and time in bed: Cross-sectional associations with cardiometabolic health in the PREDIMED-Plus study

© 2019 The Author(s). Background: This study explored the association between inactive time and measures of adiposity, clinical parameters, obesity, type 2 diabetes and metabolic syndrome components. It further examined the impact of reallocating inactive time to time in bed, light physical activity (LPA) or moderate-To-vigorous physical activity (MVPA) on cardio-metabolic risk factors, including measures of adiposity and body composition, biochemical parameters and blood pressure in older adults. Methods: This is a cross-sectional analysis of baseline data from 2189 Caucasian men and women (age 55-75 years, BMI 27-40 Kg/m2) from the PREDIMED-Plus study (http://www.predimedplus.com/). All participants had ≥3 components of the metabolic syndrome. Inactive time, physical activity and time in bed were objectively determined using triaxial accelerometers GENEActiv during 7 days (ActivInsights Ltd., Kimbolton, United Kingdom). Multiple adjusted linear and logistic regression models were used. Isotemporal substitution regression modelling was performed to assess the relationship of replacing the amount of time spent in one activity for another, on each outcome, including measures of adiposity and body composition, biochemical parameters and blood pressure in older adults. Results: Inactive time was associated with indicators of obesity and the metabolic syndrome. Reallocating 30 min per day of inactive time to 30 min per day of time in bed was associated with lower BMI, waist circumference and glycated hemoglobin (HbA1c) (all p-values < 0.05). Reallocating 30 min per day of inactive time with 30 min per day of LPA or MVPA was associated with lower BMI, waist circumference, total fat, visceral adipose tissue, HbA1c, glucose, triglycerides, and higher body muscle mass and HDL cholesterol (all p-values < 0.05). Conclusions: Inactive time was associated with a poor cardio-metabolic profile. Isotemporal substitution of inactive time with MVPA and LPA or time in bed could have beneficial impact on cardio-metabolic health. Trial registration: The trial was registered at the International Standard Randomized Controlled Trial (ISRCTN: http://www.isrctn.com/ISRCTN89898870) with number 89898870 and registration date of 24 July 2014, retrospectively registered

Perturbative transport experiments on TJ-II Flexible Heliac

Transport properties of TJ-II are explored performing perturbative experiments and taking advantage of TJ-II flexibility. Rotational transform can be varied in a wide range, which allows one to introduce low order rationals and to study their effect on transport. On the other hand, confinement properties can be studied at very different rotational transform values and for different values of magnetic shear: Experiments on influence of the magnetic shear on confinement are reported. In these cases a Ohmic current has been induced in TJ-II plasma to modify magnetic shear and to evaluate itsd effect on confinement, showing that negative shear improves the confinement. Heat transport is also reduced by locating a low order rational near the power deposition profile. Plasma potential profiles have been recently measured in some configurations up to the plasma core with the Heavy Ion Beam Probe (HIBP) diagnostic and the electric field values measured in low-density plasmas are consistent with neoclassical calculations near the plasma core. Plasma edge turbulent transport has been studied in configurations that are marginally stable due to decreased magnetic well. Results show a dynamical coupling between gradients and turbulent transport. Finally, cold pulse propagation has been studied showing ballistic non diffusive propagation

The relationship between formative assessment systems, academic performance and teacher and student workloads in higher education / Relación entre sistemas de evaluación formativa, rendimiento académico y carga de trabajo del profesor y del alumno en la docencia universitaria

Título, resumen y palabras clave también en inglésResumen basado en el de la publicaciónSe analiza la influencia que tiene la aplicación de sistemas de evaluación formativa en la docencia universitaria en el rendimiento académico del alumnado, en la carga de trabajo de alumnado y profesorado y en la satisfacción del alumnado en dichos procesos. Los datos proceden de 39 casos que emplean sistemas de evaluación formativa en la docencia universitaria, que corresponden con 15 universidades españolas y que abarcan un total de 30 asignaturas diferentes y 3625 alumnos. Se aplican estadísticos descriptivos y ANOVAS. Los resultados demuestran que el desarrollo de sistemas de evaluación formativa: produce una considerable mejora en el rendimiento académico del alumnado; es una carga de trabajo asumible dentro de la dedicación académica establecida, tanto para el alumnado como para el profesorado; el alumnado muestra una alta satisfacción con el proceso de evaluación formativa percibiendo un mayor aprendizaje respecto a modelos más tradicionales.Biblioteca del Ministerio de Educación y Formación Profesional; Calle San Agustín, 5 - 3 planta; 28014 Madrid; Tel. +34917748000; [email protected]

Product differentiation and entry barriers: Mediterranean export firms in the American markets for olive oil prior to World War II

This article analyses the entry process of Mediterranean export firms in the American markets for packaged olive oil between the 1880s and the 1930s. It explores whether those entry barriers traditionally identified by the literature emerged and to what extent they influenced such an entry process. Using trade data for the early 1930s, the article shows higher average levels of exporters' concentration in the Americas than elsewhere. It also documents that by around 1930 most of the Mediterranean firms leading packaged olive oil exports to Argentina and the USA had entered the markets on the other side of the Atlantic before World War I. Finally, it identifies product differentiation as a source of entry barrier in markets for packaged olive oil in the early 1930s. The article suggests that as the American markets for this product matured early-entrant advantages associated with the use of modern marketing became more apparent, which probably raised the cost of entry to new Mediterranean export firms during the inter-war period.olive oil, international trade, nineteenth and twentieth centuries, Mediterranean, Americas, brands, marketing, product differentiation, entry barriers, early-movers advantages, industrial organisation, economic history, international business history,