Beyond a tonnage perspective for the assessment of mineral reources. Focus on Latin America and the Caribbean

Los minerales son esenciales para mantener el estilo de vida de la sociedad moderna. En los tiempos actuales se emplean casi todos los elementos de la tabla periódica en la fabricación de dispositivos y aparatos eléctricos y electrónicos.Mientras el consumo de los minerales va en aumento, también se produce un rápido aumento la pérdida de capital mineral en los países y regiones donde se producen. Al mismo tiempo, los depósitos geológicos con altas leyes de mina han sido ya explotados, y el consumo energético para la producción de metales se ha incrementado.La preocupación sobre la importancia y el agotamiento de los recursos minerales desde hace mucho tiempo ha llamado la atención de los investigadores. Se han establecido algunas formas para valorar los recursos minerales con sus respectivas ventajas y desventajas. En el presente trabajo, en función de la revisión bibliográfica estos métodos han sido clasificados en tres categorías: por el peso, por el precio comercial y según metodologías fundamentadas en principios energéticos. El método más común de evaluar los recursos minerales ha sido probablemente según el precio. El mismo que no revela el valor de los mismos, además los precios son volátiles debido a que se encuentran sujetos a varios factores como por ejemplo, oferta-demanda, aspectos geopolíticos y especulación, entre otros. Aunque la valoración de los minerales según su peso, ha tenido un amplio desarrollo y han permitido realizar estimaciones importantes, especialmente mediante metodologías de Análisis de Flujo de Materiales (MFA por sus siglas en Inglés) y su variante EW-MFA. Entre las desventajas de estos métodos se encuentran que según esta perspectiva una tonelada de hierro es igual a una tonelada de oro, sin embargo no se toma en cuenta la escasez geológica del oro, ni el mayor requerimiento energético para su procesamiento.Una alternativa para una evaluación más adecuada de los recursos de los minerales se fundamenta en leyes energéticas. Particularmente se destacan las metodologías fundamentadas en la Segunda Ley de la Termodinámica, Exergía, que toman en cuenta no solo la cantidad, sino también la calidad de los recursos. Con base en aquello, la una división de Exergoecología plantea la evaluación de los recursos no solo en cuenta tomando en cuenta la exergía química, sino también la exergía de los recursos minerales respecto a su concentración. En tal sentido se ha establecido el concepto del costo exergético de reposición (ERC por sus siglas en Inglés). El mismo que estima la energía necesaria para concentrar los minerales desde un estado de dispersión, denominado Thanatia. La metodología de cálculo para el ERC para distintos metales, se fundamenta en análisis estadístico de información del consumo de energía para el procesamiento de metales en función de la ley de mina y extrapolaciones. Aunque los valores reportados de ERC han sido importantes para estimar la pérdida de capital mineral, estos fallan, por su método de cálculo en una estimación más precisa de los recursos minerales. En tal sentido, se hace necesario una nueva metodología de cálculo de ERC tomando en cuenta criterios de procesamiento de minerales y sus tecnologías actuales. Por tanto, en la presente tesis doctoral se establece una metodología estimar valores más precisos de los ERC en función del análisis de los procesos minero-metalúrgicos para la concentración de minerales. Esto mediante de modelos computacionales realizados a partir de un reconocido paquete informático HSC.En función de disponibilidad de información y de los requerimientos de metales para nuevas tecnologías se han escogido tres metales claves producidos en América Latina y El Caribe. Estos metales son el hierro, cobre y oro. Para estos tres metales se determinan los nuevos valores de ERC a partir de HSC y se realiza una comparación con los valores anteriores. Aunque a nivel cualitativo la importancia de los metales es la misma respecto a los valores anteriores y nuevos de ERC, su diferencia es en órdenes de magnitud. También se enfatiza en la búsqueda de mecanismos sostenibles para la producción de metales, así como en el reciclaje. Finalmente, se revela la importancia de continuar con la elaboración de más modelos en HSC para estimar valores más precisos de ERC para el resto de minerales.Minerals are essential to maintain the lifestyle of modern society. Currently, almost all the elements of the periodic table are used in the manufacture of electrical and electronic devices While the consumption of minerals is increasing, there is also a rapid increase in the loss of mineral capital of the countries and regions where they metals are produced. At the same time, geological deposits with higher ore-grades have already been already exhausted, and the energy consumption for metal production has also increased. The concern about the importance and depletion of non-fuel mineral resources have long attracted the attention of researchers, who have established some methodologies for the assessment of mineral resources. These methodologies have their respective advantages and disadvantages. In the present work, based on the literature review, these methods have been classified into three categories: by weight, by wholesale price and methodologies based on energy principles. The most common method for valuing non-fuel mineral resources has probably been according to price. This method does not reveal the real value of minerals, in addition prices are volatile because they are subject to several factors such as supply and demand, geopolitical aspects and speculation, among others. Although the assessment of non-fuel minerals according to their weight, has had a comprehensive development and have allowed realizing important estimations, primarily through methodologies of Material Flow Analysis (MFA) and its variant EW-MFA. Among the disadvantages of these methods are that according to this perspective a ton of iron is equal to one ton of gold. However, the geological shortage of gold or the higher energy requirement for processing is not taken into account. An alternative for an adequate evaluation of mineral resources is based on energy laws. Particularly noteworthy are the methodologies based on the Second Law of Thermodynamics, Exergy. The latter takes into account not only the quantity but also the quality of the resources. Based on that, a division of Exergoecology proposes the evaluation of non-fuel minerals not only taking into account the chemical exergy, but also the exergy of mineral resources concerning their concentration. In this regard, the concept of exergy replacement cost (ERC) has been established. ERC estimates the energy needed to concentrate minerals from a state of dispersion, coined as Thanatia. The calculation methodology for the ERC for different metals has been based on a statistical analysis of energy consumption information for metal processing and extrapolations. Although the reported values of ERC have been influential in estimating the loss of mineral wealth, they fail, because of their method of calculation in a more accurate estimation of valuing mineral resources. In this regard, a new methodology for calculating ERC is necessary, which takes into account mineral processing criteria and current technologies. Therefore, in the present doctoral thesis, a method is established to estimate more precise values of the ERC in the function of the analysis of the mining-metallurgical processes for the concentration of minerals. This has been done through computer models made from a well-known computer software HSC. Based on the availability of information and the requirements of metals for new technologies, three key metals produced in Latin America and the Caribbean have been selected. These metals are iron, copper, and gold. For these three metals, the new ERC values are determined from HSC and a comparison is made with the previous values. Although at a qualitative level the importance of metals is the same concerning the last and new values of ERC, their difference is in orders of magnitude. Emphasis is also placed on the search for sustainable mechanisms for the production of metals, as well as recycling. Finally, it is revealed the importance of continuing with the elaboration of more models in HSC to estimate more precise values of ERC for the rest of the minerals.<br /

El libro electrónico como apoyo a la docencia práctica de la Epidemiología

Memoria ID11-145. Ayudas de la Universidad de Salamanca para la innovación docente, curso 2011-2012

E-manual como apoyo a la docencia teórica de la epidemiología

Memoria ID12-0237. Ayudas de la Universidad de Salamanca para la innovación docente, curso 2012-2013

Evaluation of Maternal and Child Health Interventions in Africa Subsaharian

The health of woman and children in developing countries is seriously violated. Specifc tagets were set in 2000 at the United Nations Summit to improve it. Numerous interventions in maternal and child health in Sub-Saharan Africa have been implemented since. Not all of them have had the desired results. It is important to evaluate its effectiveness in the field to outline action plans, and therefore progress towars universal and quality health care in the most precarious environments.La salud de las mujeres y los niños en países en vías de desarrollo está seriamente vulnerada. En la cumbre de las Naciones Unidas del año 2000 se fijaron objetivos específicos para mejorarla. Las intervenciones en Salud Materno-Infantil en África Subsahariana que se han llevado a cabo desde entonces son numerosas. No todas ellas han tenido los resultados deseados. Es importante analizar su efectividad en el terreno para perfilar los planes de acción y por tanto progresar en de salud universal y de calidad en los entornos más deficitario

Use of Meditation and Cognitive Behavioral Therapies for the Treatment of Stress, Depression and Anxiety in Students. A Systematic Review and Meta-Analysis

The prevalence of mental health problems within students due to high academic demands and learning difficulties is a current challenge the field of education. The aim of this study is to review the scientific literature in order to analyze the effect produced by cognitive-behavioral programs and meditation strategies on stress, anxiety, and depression in students. A further aim is to identify the determinants of treatment success. The bibliographic search was carried out using Web of Science, specifically in the categories of “Education and Educational Research” and “Psychology”, obtaining a sample of 122 articles published between 2007 and 2018. Studies were included which had a pre-experimental or quasi-experimental design and included pre-test and post-test phases. Following application of inclusion criteria, 34 articles were selected for inclusion in a meta-analysis of the random effects of each variable. This obtained an average effect size of -0.41 for stress, -0.37 for anxiety, and -0.30 for depression. Three moderating variables were analyzed, with significant correlations being found for the type of treatment relating to stress (Q = 11.01, df = 2, p = 0.004, R2 = 0.294) and depression (Q = 6.14, df = 2, p = 0.048; R2 = 0.436). The stage of education of the individuals was also found to impact upon anxiety intervention success (Q = 13.093 df = 2, p = 0.0009, R2 = 0.196). Interventions mainly addressed the importance of meditation strategies, mindfulness programs, and cognitive-behavioral therapy to reduce stress, anxiety, and depression in students. This supports the need to increase research at an early age, considering the treatment of mental health as a key factor influencing academic performance and quality of life

Adherence to the Mediterranean diet and its association with self-concept and academic and physical domain in education science students: a cross-sectional study

Background: Mediterranean diet is considered to be a healthy and convenient diet model due both to its physical and mental benefits. Therefore, the aim of the present research is to detail diet pattern, academic performance and self-concept, anxiety and physical activity practice in university students, as well as to establish relationships between the variables. Methods: A descriptive and cross-sectional study was carried out with a sample of 558 undergraduates at the University of Granada, using an Ad Hoc Socio-Academic Questionnaire, the PREDIMED, Self-concept Form-5 and BAI tests to collect the data. Results: The results obtained show that a high percentage of the sample practices more than three hours of physical activity per week, needs to improve their diet, reflects low levels of anxiety and shows higher scores in academic self-concept. Conclusions: A positive adherence to the Mediterranean diet shows improvements in academic performance and in the physical, social and academic aspects of ”self-concept”

Design and Validation of the Non-Verbal Immediacy Scale (NVIS) for the Evaluation of Non-Verbal Language in University Professors

Knowledge and awareness of how to use non-verbal language is essential for the educational field. For this reason, the aim of this study was to develop a validation that validly and reliably measures the analysis of non-verbal language in university teachers. Content validation was carried out by applying the Delphi technique and through an exploratory and confirmatory analysis. The validity of understanding is given by the application of the scale to 1316 university teachers between 24 and 67 years of age. The initial data collected through the Delphi technique provided some modifications. The final scale, called Non-verbal immediacy, was composed of a total of 26 items that presented satisfactory adjustments in both comprehension and outcome validity. Confirmatory factor analysis determined three dimensions (kinesics, paralanguage, and proxemics). These factors will be a new element for future lines of research related to the teaching-learning process, as high relationships have been demonstrated between non-verbal language and psychosocial aspects implicit in teaching practice, as well as comprehension and student learning

Motivation, Self-Concept and Discipline in Young Adolescents Who Practice Rhythmic Gymnastics. An Intervention

This study aims to develop an intervention based on TARGET strategies in young people practicing rhythmic gymnastics, with the aim of observing whether motivation, discipline, self-concept and flexibility are improved. This research is a longitudinal study of a quasi-experimental nature. A total of 104 young adolescents between the ages of 11 and 12 years (11.66 ± 0.47) participated in the study, of which 60 belong to the control group and 44 to the experimental group. The intervention programme lasted two months (17 sessions). TARGET strategies were applied to the experimental group during training. While the experimental group continued with its routine training. To measure the psychological variables, the instrument used were the Youth Physical Self-Concept Scale (C-PSQ), Reason Scale for Discipline (RSD) and Success Perception Questionnaire (SPQ), and for flexibility, the tests were applied to the Sit and Reach and Deep trunk flexion test. The results showed that those teenagers who participated in the intervention, obtained an increased climate task, which entails an enjoyment by the practice of physical activity itself, more optimal levels of physical self-concept and discipline, subsequently, obtaining better results of flexibility. While in the control group gymnasts the ego climate and demotivation increased. TARGET strategies applied to young adolescents have positive effects, improve motivation towards physical activity, self-concept and discipline. This results in greater performance in flexibility. This will encourage young adolescents to continue to engage in physical activity in the future

Effectiveness of a Judo Intervention Programme on the Psychosocial Area in Secondary School Education Students

Currently, many combat sports are pedagogically conceived as uneducational and unreliable for the development of young people. The present research aims to investigate the influence of a Judo intervention programme on the motivational climate towards sport, aggressive behaviour, emotional intelligence, and self-concept in secondary school students and to establish the relationships between them. This objective was broken down into (a) developing an explanatory model of the variables mentioned above and (b) testing the model equations through a multi-group analysis in terms of pre-test and post-test. The present study conducted a pre–post-test quasi-experimental design with a single experimental group. The sample consisted of a total of 139 adolescents (12.67 ± 1.066), 50.4% of whom were male (n = 70) and 49.6% female (n = 69). The results show that the intervention decreased all types of aggression and increased levels of emotional intelligence. An increase in social, physical and academic self-concept and decreases in the family and emotional areas were also observed. Finally, for the motivational climate, a tendency towards the ego climate to the detriment of the task climate was observed. It is concluded that the Judo intervention programme is effective in decreasing aggressive behaviour and effective in increasing levels of emotional intelligence and self-concept

Motivational Climate, Anxiety and Physical Self-Concept in Trainee Physical Education Teachers—An Explanatory Model Regarding Physical Activity Practice Time

There is an increase in sedentary lifestyles among young people. However, the development of a certain motivational climate can play a key role in the prevention of such lifestyles. Taking into account the aforementioned, the present research aims to establish the relationship between the motivational climate towards sport, anxiety and physical self-concept and to identify and clarify the existing relationships between anxiety, motivational climate and physical self-concept, by breaking down this objective into (a) developing an explanatory model of the motivational climate towards sport and its relationship with anxiety and physical self-concept and (b) contrasting the structural model by means of a multi-group analysis, according to the time spent doing physical activity per week. For this purpose, a cross-sectional descriptive and comparative study was carried out with a total of 568 university students (M = 25.09; SD = 6.22). A sociodemographic questionnaire, the Spanish version of the Perceived Motivation Climate Questionnaire in Sport, the Self-Concept Form-5 and the Beck Anxiety Inventory were used for data collection. The results show that more time spent doing physical activity brings benefits in terms of physical self-concept and homework climate, helping to reduce anxiety levels. As conclusions, it is observed that a longer time spent doing physical activity brings benefits in the channelling of disruptive states and improvements in physical self-concept