Trace elements quantification in Portuguese red wines

Dissertation for the Degree of Master in Technology and Food Safety – Food QualityThe aim of this thesis is to characterize Portuguese red wines in terms of trace elements composition. The wines were chosen so that all the country was represented and studied. For trace elements quantification (As, Hg, Cd, Ni and Pb) were tested various sample treatments including for all trace elements: acid digestion or presence and absence of spike. The need for H2O2 addition in order to oxidize organic compounds was analyzed for Hg, Cd, Ni and Pb. Quantification of all trace elements was performed with Atomic Absorption Spectrometry techniques. After the method validation were analyzed 25 Portuguese red wines and duplicates. The concentrations obtained were used to perform a statistical analysis to determine what were the regions with highest incidence of each trace element. Using Target Hazard Quotient (THQ) equation was possible to identify the regions where the concentrations found are a reason for public health concern, being values above 1 a motive for concern. After the analysis was determined that there is no need for wine samples digestion and that the presence of H2O2 is crucial. Hg and As were quantified with Hydride Generation Atomic Absorption Spectrometry; Ni and Pb with Flame Atomic Absorption Spectrometry; Cd with Electrothermal Atomic Absorption Spectrometry. The statistical results allowed to conclude that the system variation was mainly explained by the variation of Ni, As and Hg concentrations. Ni was largely found in Estremadura and Terras do Sado wines, while As and Hg were found mostly in Minho and Douro wines respectively. All of THQs determined were under 1, which is the limit value above which there is reason for health concern. Maximum THQ values were of 0.044 in Algarve wines were due to Ni

Portuguese transmission grid incidents risk assessment

Documento confidencial. Não pode ser disponibilizado para consultaTese de doutoramento. Engenharia Electrotécnica e de Computadores. Faculdade de Engenharia. Universidade do Porto. 201

Literacia virtual e ambientes e-learning

Comunicação apresentada na VII Conferência Internacional de TIC na Educação, realizada na Universidade do Minho, Braga, de 12-13 de Maio de 2011Os actuais processos de ensino-aprendizagem em rede beneficiam de um maior domínio das tecnologias de informação e comunicação por parte dos sujeitos aprendentes. No entanto, esse domínio tende a ser predominantemente instrumental, traduzindo-se num uso fluente, mas pragmático e pouco crítico. As linguagens necessárias para integrar, apropriar e compreender as interfaces e metáforas destes meios requer o desenvolvimento de competências específicas no sentido da capacitação. Os estudantes em regime de elearning constituem um campo de observáveis perferencial para a observação e análise dos estilos de uso do espaço virtual, dos estilos de comunicação e colaboração online. O aprofundamento do conhecimento daqui resultante poderá ainda permitir identificar os contributos deste tipo de ensino na promoção de competências de literacia para os média, entendida como um requisito de envolvimento cívico nas sociedades actuais. Com este artigo pretendemos aprofundar estas reflexões teóricas e conceptuais que enquadram o desenho de um projecto de investigação.The nowadays teaching and learning network processes benefit of a bigger domain of the information and communication technologies on behalf of the learners. However that domain tends to be basically instrumental becoming in practice a fluent but pragmatic and little critical use. The necessaries languages to integrate appropriate and understand that challenges’ interfaces and metaphors demand the development of particular skills throw empowerment. The e-learning students are an important empiric field to the observation and analysis of the use of virtual space styles, of the communication and online collaboration styles. To deep this knowledge will also allow to identify the contributions of this kind of teaching into the promotion of media literacy skills – as a demand of civic involvement in nowadays societies. With this paper we aim to deepen these theoretical and conceptual reflections framing a research project design

¿Cómo valoran los profesores en ejercicio y en formación unas actividades dirigidas al estudio de la reproducción en la educación obligatoria?

En este trabajo se analizan las opiniones del profesorado (en ejercicio y en formación de primaria y secundaria) sobre el valor educativo y las dificultades que encierran los aspectos conceptuales, relativos a la reproducción, que se trabajan en una serie de actividades, dirigidas al último ciclo de primaria y primer ciclo de secundaria. Los participantes valoran positivamente los aspectos tratados en las actividades e identifican dificultades. El profesorado en formación justifica en mayor medida sus opiniones que el profesorado en ejercicio. El análisis de las justificaciones muestra que éstas no siempre se centran en los aspectos clave de las actividades, percibiéndose dificultades en contenidos que exceden las intenciones de las mismas.This paper is an analysis of teacher' opinions (some are practising teachers while others are training to be Primary and Secondary School teachers) on the educational value and the problems which reproduction-related conceptual aspects treated in a number of activities, designed for the last stage of Primary Education and the first stage of Secondary. The participants value the aspects dealt with during the activities in a positive way and they likewise identify some problems. The teachers in training give reasons for their opinions to a greater extent than their practising counterparts do. Analysing these justifying reasons shows that they do not always focus on the key aspects of the above mentioned activities and it has been seen that the contents of such activities go above and beyond what they actually intend to teach

Qué actividades y qué procedimientos utiliza y valora el profesorado de Educación Primaria

This study endeavours to learn which activities are used by Primary School teachers as well as the purpose of using them. A poll was conducted among more than 500 teachers who state that they carry out different activities, even though it turned out that those textbook activities which involve the use of pen and pencil and whose objective is to develop conceptual contents have a greater presence, whereas the procedures themselves were hardly mentioned at all. A lesser number of teachers, a total of 87, valued different kinds of procedures, the most considered ones being those which correspond to skills of communication, observation and organisation of information, while those procedures that are of an intellectual nature and that involve manipulative skills were the least appreciated ones

Diseño instruccional de un sistema hypermedia para el aprendizaje de la física fundamentado en las perspectivas teóricas del cambio y del desarrollo conceptual

En este trabajo son utilizadas dos perspectivas teóricas del aprendizaje de la física para fundamentar el uso del ordenador. Ambas se centran en la construcción de conceptos científicos: la primera está asociada a la noción de cambio conceptual (CC), que presupone que el aprendizaje se da como sustitución de un concepto alternativo, que el aprendiz ya posee, por el concepto científico correspondiente; la segunda se refiere al desarrollo conceptual (DC), que resulta de un proceso continuo de integración conceptual, para el que el conocimiento intuitivo contribuye productivamente. A través de esas dos perspectivas teóricas fue posible identificar en la literatura específica algunas propuestas pertinentes, que fueron utilizadas para el diseño del sistema. Sus características guiaron la selección de los elementos necesarios para elaborar el diseño instruccional del sistema hypermedia "Fuerza & Movimiento", desarrollado para facilitar a los estudiantes la comprensión de algunos de los conceptos fundamentales de la mecánica básica.In this paper, we use two theoretical perspectives from physics learning in order to provide foundations to the use of computers. Both perspectives are centred on the construction of scientific concepts. The first one is associated to the idea of conceptual change (CC), which assumes that learning is a substitution of a scientific concept for a misconception that the learner already possesses. The second perspective refers to conceptual development (DC), which arises from a continual process of conceptual integration, in which intuitive knowledge productively contributes. Through these two theoretical perspectives, we were able to identify in the literature some relevant proposals, which were used to design the system. The perspectives guided the selection of the elements needed to elaborate the instructional design of the hypermedia system "Force & Movement". This system was developed to facilitate students' understanding of some of the fundamental concepts of basic mechanics

La importancia de las habilidades cognitivo-lingüísticas asociadas al estudio de la Astronomía desde la perspectiva del profesorado

El trabajo pretende conocer cómo valora el profesorado de Primaria y Secundaria en ejercicio y formación una serie de habilidades cognitivo-lingüísticas (descripción de hechos/fenómenos, de modelos, definición…). También se pretende conocer si los docentes establecen diferencias entre las habilidades expresadas genéricamente y en términos astronómicos, y si existen diferencias entre los grupos de docentes. Así mismos se analiza si los profesores identifican y valoran estas habilidades en actividades concretas. Los resultados muestran que los docentes valoran positivamente las habilidades, apreciándose diferencias entre las enunciadas genéricamente y en términos astronómicos y entre grupos de profesores. Los participantes tienen dificultades para identifican la habilidad cognitivo-lingüística exigidas en las actividades.The aim of this study is to find out how teachers of the last years of Primary and the first years of Secondary evaluate and what difficulties they find in relation to a series of cognitive-linguistic skills (description of facts,…). It also aims to find out whether teachers establish differences when the skills are expressed in a general sense or when they are associated to the subject of astronomy. Furthermore, it analyse if teachers identify and value these skills in specific activities. The results show that the teachers positively evaluate the skills presented, with changes being seen in terms of content. Differences between groups of teachers also were found. Participants have difficulties for identify the cognitive-linguistic skill that is demanded in the shown activities

Las actividades de primaria y ESO incluidas en libros escolares : ¿qué objetivo persiguen?, ¿qué procedimientos enseñan?

Se analizan un total de 1.340 actividades correspondientes a textos de primaria y ESO de tres editoriales de amplia implantación, dirigidas al estudio de tres tópicos: materia, animales y vegetales. Se estudia, además de la importancia otorgada por las editoriales a estos tópicos, el objetivo que persiguen las actividades y los procedimientos que enseñan. Se detecta que en primaria se insiste más en seres vivos que en materia. La aplicación de la teoría que figura en el texto y la adquisición de conocimientos son los objetivos más abundantes en las actividades, siendo prácticamente inexistentes las dirigidas a la indagación. En coherencia con ello, los tipos de procedimientos más abundantes son la comunicación y la organización de la información en detrimento de los asociados a la resolución de problemas (formulación de hipótesis, análisis de datos, control de variables...).The objective of this study is to analyse a total of 1.340 activities which correspond to Primary School and Compulsory Secondary Education textbooks produced by three widely established publishing houses and which are aimed at studiyng the following three topics: matter, animals and vegetables. The importance given to these topics by the publishing houses, the objective which the activities pursue as well as the procedures they teach are also studied. A greater emphasis on living beings than on matter has been detected in the Primary School material. Applying the theory which figures in the textbooks and acquiring the knowledge contained therein are the most abundant objectives which are found in the activities, whereas those activities which are aimed at investigation tasks are virtually non-existent. In tune with what has been said before, the most abundant types of procedures are the communication and organisation of information to the detriment of the ones that are associated with problem solving (formulating hypotheses, data analys, controlling variables...)