The effect of two anionic membranes (AMI 7001s and Neosepta AMX) on the electrodeposition of manganese from sulphate solutions.

The effect of two different anionic membranes on manganese deposition was studied in a two-compartment electrochemical reactor with a titanium cathode and a dimensionally stable RuO2|Ti anode. Chronopotentiometry, ICP-OES, SEM, XRD and elemental mapping were used to understand the changes in concentration and characteristics of the metallic deposition at different current densities with the anionic membranes AMI 7001s and Neosepta AMX. The results demonstrate that AMI reduces more manganese than AMX below -100 A m-2, generating more metallic deposition but also more low-solubility manganous by-products, whereas both membranes exhibited similar behaviours above -100 A m-2 reaching the maximum current efficiency (63%) at -200 A m-2. It was also observed that the membranes have a significant effect on sulphate consumption since they are anions.

Selenium and sulphur reactions involved in manganese reduction from sulphate solutions.

Electrochemical reduction of ionic species during manganese deposition from sulphated aqueous solutions has been studied in an electrochemical reactor with two anionic exchange membranes. Thermodynamic analysis, voltammetries, and chronopotentiometries were used to determine the reaction mechanism of the reductions developed, with the results demonstrating that the effect of the elemental selenium on the hydrogen evolution leads to the formation of elemental sulphur by reducing the sulphate ions with both membranes. It was also evident that in the range of -25 to -50 A m-2 the electrodeposition of metallic manganese begins, with minimal interference from parasitic reactions.

Ejercicio, bienestar psicológico, calidad de sueño y motivación situacional en estudiantes de educación física / Exercise, psychological well-being, sleep quality and situational motivation in physical education students / Exercício, bem-estar psicológico, a qualidade do sono e motivação situacional em estudantes de educação física

El objetivo de este trabajo ha sido comprobar si la exposición a diferentes intensidades de actividad física aguda ocasionaba cambios en el bienestar psicológico (vitalidad subjetiva y estado afectivo), la calidad del sueño y la motivación intrínseca situacional en estudiantes adolescentes en clases de educación física. Para ello, 120 estudiantes (50 chicos y 70 chicas) con edades comprendidas entre los 16 y 20 años completaron, antes y después de pasar por cada situación experimental, medidas de estas variables. Los resultados mostraron, en primer lugar, que había asociaciones directas entre la vitalidad subjetiva, el estado afectivo positivo y la calidad del sueño. En segundo lugar, se encontró un incremento significativo en la motivación intrínseca situacional y disminución en el estado afectivo negativo post-sesión al comparar las intensidades vigorosa y ligera. La mayoría de las dimensiones del bienestar psicológico mejoraban cuando se comparaban las situaciones pre intervención y post intervención, independientemente de la intensidad del ejercicio. Contrariamente a nuestras hipótesis, la calidad del sueño no mejoró al practicar actividad física. La principal conclusión es que la realización de actividad física aguda, independientemente de la intensidad del mismo, mejora el bienestar. Respecto a la motivación, la actividad física vigorosa es la que provoca mayores cambios motivacionales, debiendo tener este aspecto en cuenta a la hora de diseñar programas de actividad física para adolescentes (AU)

The aim of this study was to determine how the exposure to different intensities of acute physical activity, caused changes in psychological well-being (subjective vitality and affective state), sleep quality and situational intrinsic motivation in adolescent students on physical education classes. 120 students (50 boys and 70 girls) aged between 16 and 20 years, completed different questionnaires to measure these variables. The results showed direct and positive associations between subjective vitality, positive affect state and the quality of sleep and significant differences, increasing situational intrinsic motivation and decreasing post-session negative affect when comparing light and vigorous intensities. Almost all dimensions of psychological well-being improved when comparing the preintervention and post intervention situations, regardless of physical activity intensity. Contrary to our hypothesis, sleep quality did not improve by practice of physical activity. The main conclusion is that the acute exercise, regardless of intensity, improves well-being and that vigorous physical activity is causing major motivational changes, must take this into account when designing physical activity programs for adolescents (AU)

O objectivo deste trabalho consistiu em comprovar se a exposição a diferentes intensidades de exercício agudo ocasionava alterações no bem-estar psicológico (vitalidade subjectiva e estado afectivo), na qualidade de sono e na motivação intrínseca situacional de estudantes adolescentes em aulas de educação física. Para tal, 120 estudantes (50 rapazes e 70 raparigas) com idades compreendidas entre os 16 e os 20 anos preencheram, antes e depois de passarem por cada situação experimental, instrumentos de medida destas variáveis. Os resultados mostraram, em primeiro lugar, que havia associações directas entre a vitalidade subjectiva, o estado afectivo positivo e a qualidade de sono. Em segundo lugar, verificou-se um incremento significativo na motivação intrínseca situacional e uma diminuição do estado afectivo negativo após a sessão, ao comparar as intensidades vigorosa e ligeira. A maioria das dimensões do bem-estar psicológico melhorou quando comparadas as situações pré-intervenção e pós-intervenção, independentemente da intensidade do exercício. Contrariamente às nossas hipóteses, a qualidade de sono não melhorou ao praticar actividade física. A principal conclusão é a de a realização de exercício agudo, independentemente da sua intensidade, melhora o bem-estar. Relativamente à motivação, a actividade física vigorosa é a que provoca maiores alterações motivacionais, devendo ter-se este aspecto em consideração quando forem desenhados programas de actividade física para adolescentes (AU)

Measuring self-determination motivation in a physical fitness setting: validation of the Behavioral Regulation in Exercise Questionnaire-2 (BREQ-2) in a Spanish sample.

AIM: The aim of this study is the validation in the Spanish context of the Behavioural Regulation in Exercise Questionnaire-2 (BREQ-2) scale, developed by Markland et al., from the point of view of the self-determination theory and to compare the effect of gender, age and exercise duration and mode. METHODS: For the validation of the instrument, two studies were carried out (n=250 and n=311) with a total sample formed of 561 adults in the metropolitan area of the city of Murcia, Spain, who do non-competitive sport and physical activities. They were given the adaptation of the questionnaire BREQ-2 by Markland et al. to fill in. RESULTS: After an exploratory factor analysis and a confirmatory factor analysis, an adaptation of the scale was obtained with 18 items and 5 factors with acceptable reliability coefficients and a total variance explained of 68.8%. The two highest assessed forms of behavioral regulation were intrinsic and identified, with the women showing more intrinsic regulation. Those that exercised for less time were the ones that showed higher levels of amotivation and the older people showed a greater tendency to identified regulation. CONCLUSION: The BREQ-2 scale has all the required conditions, as far as reliability and validity criteria are concerned, to be used in the Spanish context in different areas of physical activity.

Prescripción de ejercicio físico para el acondicionamiento muscular en el medio acuático / Physical exercise prescription for muscular fitness in the water medium

La actual diversificación de la práctica acuática está llevando a replantearse algunos métodos de trabajo en dicho medio. Uno de los aspectos que nos preocupa en este campo son los beneficios para la salud que puede provocar el trabajo de la fuerza muscular en el medio acuático. Para ello, se presenta una propuesta de metodología en la que se analizan aspectos tales como las consideraciones a tener en cuenta dependiendo del género y la edad del usuario, además de mostrar como el equipamiento se puede convertir en un excelente recurso material para aumentar la intensidad del ejercicio y para diversificar las prácticas. Así pues, el objetivo que persigue la siguiente revisión es mostrar como es posible mejorar la fuerza muscular a través del trabajo en el medio acuático. (AU)