Early Diagenesis of Lower Pliensbachian Sediments from the Algarve Basin (Portugal): Characterisation and Relation with Tectonic Evolution

The Lower Jurassic (Lower Pliensbachian) sedimentary record of the western end of the Algarve Basin (Portugal) is made of decimetric thick layers of limestone and dolomitized limestone with chert nodules and inter-layered chert beds. Most of the observable lithologies are the product of an early diagenetic evolution and the original lithological content of the formation included limestones, marls and calciclastic limestones. In this area the sedimentation was controlled by the tectonic stretching responsible for the evolution of the Algarve Basin, as well as by short-lived events of tectonic inversion. These episodes of tectonic inversion were responsible for the some uplift with the development of unconformities, sometimes with erosional surfaces separating the different sedimentary packages. The early diagenesis affecting the Lower Pliensbachian sediments is characterized by: (i) a mechanical event controlled by the syn-sedimentary stretching, responsible for the development of calciclastic dikes and nodules alignements; (ii) the substitution of the carbonates from the most permeable calciclastic limestone layers by silica, leading to the development of the observed cherts; (iii) the dolomitization of the preserved limestones; and (iv) the infilling of joints and normal fault planes by silica-rich fluids leading to the development of quartz veins. This set of diagenetic transformations took place before the Upper Pliensbachian which lacks the evidences of their occurrence. The whole-rock geochemical data of the carbonate and siliceous sediments of the Lower Pliensbachian revealed some affinities between both lithological types namely the lack of Ce anomalies and the presence of La anomalies in the REE patterns of all samples. The similarities between the carbonate lithologies which diagenetic evolution is marked by the replacement of calcite by dolomite and the siliceous sediments derived from the replacement of calcite by quartz establish a chemical connection between the two sets of rocks. This connection can be interpreted as a testimony of a common primary precursor for both lithological groups or as a testimony of a common character of the diagenetic fluids which interacted with the original sediments. The dolomitization changed the Sr isotopic signature increasing the 87Sr/86Sr ratios from 0.7073 in the unchanged limestone to a maximum value of 0.7113 in the dolomitized samples. This strong increase together with the 13C/12C and 18O/16O values support an external origin for the dolomitizing fluids. A possible origin for the diagenesis is meteoric water coming into the basin after weathering the country rocks. The hydrologic regime in the basin certainly underwent important changes during the uplift events associated to the mentioned tectonic inversion episodes and uplift allowing for input of water from land

Early Diagenesis of Lower Pliensbachian Sediments from the Algarve Basin (Portugal): Characterisation and Relation with Tectonic Evolution

The Lower Jurassic (Lower Pliensbachian) sedimentary record of the western end of the Algarve Basin (Portugal) is made of decimetric thick layers of limestone and dolomitized limestone with chert nodules and inter-layered chert beds. Most of the observable lithologies are the product of an early diagenetic evolution and the original lithological content of the formation included limestones, marls and calciclastic limestones. In this area the sedimentation was controlled by the tectonic stretching responsible for the evolution of the Algarve Basin, as well as by short-lived events of tectonic inversion. These episodes of tectonic inversion were responsible for the some uplift with the development of unconformities, sometimes with erosional surfaces separating the different sedimentary packages. The early diagenesis affecting the Lower Pliensbachian sediments is characterized by: (i) a mechanical event controlled by the syn-sedimentary stretching, responsible for the development of calciclastic dikes and nodules alignements; (ii) the substitution of the carbonates from the most permeable calciclastic limestone layers by silica, leading to the development of the observed cherts; (iii) the dolomitization of the preserved limestones; and (iv) the infilling of joints and normal fault planes by silica-rich fluids leading to the development of quartz veins. This set of diagenetic transformations took place before the Upper Pliensbachian which lacks the evidences of their occurrence. The whole-rock geochemical data of the carbonate and siliceous sediments of the Lower Pliensbachian revealed some affinities between both lithological types namely the lack of Ce anomalies and the presence of La anomalies in the REE patterns of all samples. The similarities between the carbonate lithologies which diagenetic evolution is marked by the replacement of calcite by dolomite and the siliceous sediments derived from the replacement of calcite by quartz establish a chemical connection between the two sets of rocks. This connection can be interpreted as a testimony of a common primary precursor for both lithological groups or as a testimony of a common character of the diagenetic fluids which interacted with the original sediments. The dolomitization changed the Sr isotopic signature increasing the 87Sr/86Sr ratios from 0.7073 in the unchanged limestone to a maximum value of 0.7113 in the dolomitized samples. This strong increase together with the 13C/12C and 18O/16O values support an external origin for the dolomitizing fluids. A possible origin for the diagenesis is meteoric water coming into the basin after weathering the country rocks. The hydrologic regime in the basin certainly underwent important changes during the uplift events associated to the mentioned tectonic inversion episodes and uplift allowing for input of water from land

Environmental education in Portuguese language classes

[Resumo] Este trabalho propõe-se a divulgar os resultados de uma pesquisa desenvolvida em duas turmas da 3ª série do Ensino Médio, em uma escola pública do Distrito Federal/Brasília/Brasil, durante o ano letivo de 2012. O objetivo foi analisar o ensino de Língua Portuguesa e a Educação Ambiental, partindo-se da postulação de que é possível a integração dessas duas áreas. Para isso, abordamos o ensino de Língua Portuguesa, a Educação Ambiental e a interdisciplinaridade. A geração de dados para esta análise se deu através da pesquisa-ação, cujos instrumentos foram observação, aplicação de questionário, conversa gravada, produção de diário de itinerância, elaboração e aplicação de sequências didáticas. Os resultados evidenciam que é possível sim unir Língua Portuguesa e Educação Ambiental, com a prática da interdisciplinaridade, conforme a avaliação dos implicados na pesquisa: alunos, professora e pesquisadora. A partir da experiência desenvolvida, vislumbra-se a possibilidade de um trabalho integrado do ensino de língua materna e da temática ambiental na educação básica.[Abstract] This work presents the results of a research carried out in two classes of the senior year of high school in a public school of the Federal District, Brazil, in the school year of 2012, with the purpose of analyzing the interdisciplinary study of textual genres integrating the areas of Environmental Studies and Portuguese as a mother tongue. Our basic assumption was that the work with textual genres can offer answers to sociocultural as well as to linguistic issues. The generation of data for this analysis was through action research, whose instruments were watching, a questionnaire, recorded conversation, daily production of roaming, development and implementation of didactic sequences. The participants were the students, the teacher and the researcher. The results indicate the adequacy of an academic work integrating Portuguese as a mother tongue and the transversal themes of the basic education curriculum in Brazil

Analog and digital games as a pedagogical tool in the teacher training context

This article focuses on analog and digital game play and the challenges it poses to future teachers in an educational context. For that, a review of the literature on the subject was made, addressing the theories of Piaget and Vygotsky. We refer to the game as a pedagogical resource, its relation to the teaching-learning process, and its role in stimulating the multiple intelligences referenced by the psychologist Howard Gardner. Structurally framed by this theoretical framework, we developed this study in an integrated internship context in a classroom of the First Cycle of Basic Education, with 20 children ages 9 and 10. In order to carry out this research, we developed teaching-learning experiences that allowed us to answer the following question: How do the different game supports (analog/digital) motivate children to the teaching-learning process? In order to answer this question, we have outlined the following objectives: i) to understand if the type of support in which children play influences learning; ii) develop activities in contexts, using games (analog and digital); (iii) understand, to what extent, playing games encourages the development of multiple skills. The study is part of a descriptive, interpretive, and reflexive process, framed in a qualitative approach. For data collection, we used participant observation, observation log grids, field notes, photographic records, and interviews with the children. After analyzing the data, these tend to reveal, among other aspects, a remarkable improvement in motivation of children, perceiving that the game is an excellent teaching/learning strategy that allows the development of social and communication skills of children, predisposing the child for learning. As far as the type of game support is concerned, we found that although digital is more appealing to children born in the Digital Age, we verified that both the game in analog and digital support, when properly integrated into the educational action, are also promoters of meaningful and lasting learning.info:eu-repo/semantics/publishedVersio

Exploring individuals perception of non-sponsored branded user generated content, the affect on its use and the outcome of digital engagement on Instagram

With the rise of social media importance came the rise of the user and its role in the market. Users become actors, advisors, critiques, advocates and they reveal their nonsponsored branded voice. This study proposes an examination of the User Generated Content (UGC) and its influence on the social media platform Instagram. Regarding the existent literature, this research suggests a connection between three dimensions, value, use and digital engagement on social media platform, Instagram. More specifically, the proposed model established that depending on the value each individual attributes to non-sponsored branded UGC, it will lead to different types of usages. These types of use will then lead to two possible digital outcomes on Instagram. Using the data gathered from the 402 responses, the model was tested using PLS-SEM and conclusions were drawn. All the hypothesis tested were validated and results confirmed that there is a positive connection between all thee dimensions, UGC value, UGC use and digital engagement. Consequently, results also indicated that the most significant relationship is between the social value of non-sponsored branded UGC and UGC contribution, followed by the functional value of non-sponsored branded UGC and UGC consumption. In the end of the research, the meaning of the findings and the future possible research were deliberated.Com a ascensão da importância das redes sociais veio o crescimento do utilizador e do seu papel no mercado. Os utilizadores tornam-se atores, conselheiros, críticos, defensores e revelam a sua verdadeira voz. Este estudo propõe examinar o papel do user generated content (UGC) e a sua influência na rede social, Instagram. Com base na literatura existente, esta pesquisa propõem uma conexão entre três dimensões, o valor, o uso o do user generated content e o seu compromisso digital na rede social, Instagram. Mais especificamente, o modelo proposto estabelece que dependendo do valor que cada indivíduo atribui ao conteúdo não patrocinado gerado pelos utilizadores (UGC) levará a diferentes tipos de utilização. Estas formas de utilização de conteúdo poderão levar a dois possíveis efeitos de compromisso digital no Instagram. Usando os dados das 402 respostas obtidas, o modelo foi testado usando PLS-SEM e conclusões foram retiradas. Todas as hipóteses testadas foram validadas e os resultados confirmam a existência de uma conexão positiva entre as três dimensões, valor, uso e compromisso digital. Consequentemente os resultados revelam, também, que as relações mais significativas ocorrem entre o valor social do UGC e a contribuição para esse conteúdo, seguido pelo o valor funcional do UGC e o subsequente consumo desse conteúdo. No final da pesquisa, é proposta uma justificação para os resultados alcançados e são deliberadas as possíveis futuras investigações neste assunto

Blinking Lights in Taurus: Long-term Variability of Young Stars and Brown Dwarfs

Tese de mestrado, Física (Astrofísica e Cosmologia), Universidade de Lisboa, Faculdade de Ciências, 2022Young stellar and substellar objects are known to change their apparent brightness in an irregular way. By studying this variability from the optical to mid infrared it is possible to uncover information on the underlying physics. Several effects are imprinted in the light curves, from change of extinction, spot activity and accretion phenomena. The Taurus star forming region is one of the closest star forming regions to the Solar System, containing a rich population of newly formed stellar and substellar sources. We present an analysis of long-term variability for a set of 491 spectroscopically confirmed young sources in Taurus. We use multi-epoch photometry optical data from the Zwicky Transient Facility (ZTF) and mid-infrared data from AllWISE survey. Using various variability indices, we selected 304 (79%) optical variables based on ZTF data and 279 (62%) mid-infrared variables from AllWISE. In the optical data we visually classify the light curves and find that most present visual bursts. To infer the possible origins of variability, we study the trajectories of the sources in color-magnitude diagrams and determine their properties. By comparison with the properties obtained from simple toy models, we can explain much of the observed variability as being due to accretion, hot spots, as well as changes in the amount of extinction. Using AllWISE data we also find that the observed variability causes changes in the determination of the YSO class and observe that 80 sources (32%) experience a change in class. This means that the number of sources in a particular class can change over time due to their variability, which can impact important physical parameters such as the star formation rate, or studies of the protoplanetary disk evolution with time

Avicena e as ciências mistas

Some of Aristotle’s texts (Physics II,2; Posterior Analytics I, 7, 9 and 13) mention some sciences (astronomy, harmony, optics and mechanics – the last one only in Posterior Analytics) in the context of the distinction between physics and mathematics (in Physics), the impossibility of using the demonstrations of one science in another one (metabasis) and the distinction between proofs of what and why (in Posterior Analytics). These texts allowed his commentators – especially the Arabic and Latin ones – to approach the epistemic status of such sciences. The present study seeks to examine how Avicenna – or more precisely, the Latin Avicenna – dealt with this issue in Liber primum naturalium, and what he would have added to Aristotle’s text. In this regard, it is possible to point out to the addition of at least two more sciences to Aristotle’s list (science of the spheres in motion and science of weights), a formal definition of this type of sciences, implying their mixed nature (Avicenna refers to astronomy): “this science is as if it were mixed from the natural and the disciplinary [mathematics] ones. As the pure disciplinary one is abstract, in no way in matter, and this one is as if inserting the abstract one in designated [determined] matter”. It is also noteworthy a terminology that cannot be found in Aristotle’s text: “mixed science” – in the Arabic text, “participating” (mushtarak) or “compounded” (murakkab) science -, “pure and inserted science”, “abstraction”.Algunos textos de Aristóteles (Física II,2; Segundos Analíticos I,7,9 y 13) mencionan ciertas ciencias (astronomía, armónica, óptica y mecánica - esta última a penas en los Segundos Analíticos) a propósito de la distinción entre física y matemática (Física), de la imposibilidad de usar demostraciones de una ciencia en otra (metábase) y de la distinción entre una prueba de qué y de por qué (Segundos Analíticos). Estos textos indujeron a los comentaristas, especialmente árabes y latinos, a ocuparse de la situación epistémica de estas ciencias. En esta comunicación, se pretende examinar como Avicena - más precisamente, el Avicena latino - trata este tópico en Liber primus naturalium, y aquello que adiciona al texto de Aristóteles. En este sentido, es posible indicar la adición de dos ciencias más en la lista de Aristóteles (la ciencia de las esferas en movimiento y la ciencia de los pesos), una definición formal de este tipo de ciencias, como si implicando su carácter misxto (Avicena se refiere a la astronomía): "esta ciencia es como si fuera mixta de la natural y de la disciplinar [matemática]. Visto que la disciplinar pura es abstracta, de ningún modo en la materia, y ésta es como que insertando esta abstracta en la materia designada [determinada]". Obsérvese también terminología que no se encuentra en el texto de Aristóteles: "ciencia mixta" - en el texto árabe ciencia "participante" (mushtarak) o "compuesta" (murakkab)-, "ciencia pura e insertada", "abstracción".Alguns textos de Aristóteles (Física II, 2; Segundos Analíticos I, 7, 9 e 13) mencionam certas ciências (astronomia, harmônica, ótica e mecânica, esta última apenas nos Segundos Analíticos) a propósito da distinção entre física e matemática (na Física), da impossibilidade de usar demonstrações de uma ciência em outra (metábase) e da distinção entre uma prova de quê e de por quê (nos Segundos Analíticos). Estas passagens deram ocasião a que seus comentadores, sobretudo árabes e latinos, se ocupassem com a situação epistêmica de tais ciências. Pretende-se nesta comunicação examinar como Avicena, ou mais precisamente o Avicena Latino, trata deste tópico no Liber primus naturalium e o que acrescentaria ao texto de Aristóteles. Seria possível, quanto a isto indicar pelo menos o acréscimo de mais duas ciências à lista de Aristóteles (ciência das esferas em movimento e ciência dos pesos), uma definição formal deste tipo de ciências, como implicando seu caráter misto (Avicena está falando da astronomia): “esta ciência é como que se fosse mista da natural e da disciplinar [matemática]. Visto que a disciplinar pura é abstrata, de modo nenhum na matéria, e esta é como que inserindo esta abstrata na matéria designada [determinada]”. Note-se também uma terminologia não encontrada no texto de Aristóteles: “ciência mista” – no texto árabe ciência “participante” (mushtarak) ou “composta” (murakkab) –, “ciência pura e inserida”, “abstração”