841 resultados para Geometrical concepts
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One of the simplest models of adaptation to a new environment is Fisher's Geometric Model (FGM), in which populations move on a multidimensional landscape defined by the traits under selection. The predictions of this model have been found to be consistent with current observations of patterns of fitness increase in experimentally evolved populations. Recent studies investigated the dynamics of allele frequency change along adaptation of microbes to simple laboratory conditions and unveiled a dramatic pattern of competition between cohorts of mutations, i.e., multiple mutations simultaneously segregating and ultimately reaching fixation. Here, using simulations, we study the dynamics of phenotypic and genetic change as asexual populations under clonal interference climb a Fisherian landscape, and ask about the conditions under which FGM can display the simultaneous increase and fixation of multiple mutations-mutation cohorts-along the adaptive walk. We find that FGM under clonal interference, and with varying levels of pleiotropy, can reproduce the experimentally observed competition between different cohorts of mutations, some of which have a high probability of fixation along the adaptive walk. Overall, our results show that the surprising dynamics of mutation cohorts recently observed during experimental adaptation of microbial populations can be expected under one of the oldest and simplest theoretical models of adaptation-FGM.
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Dark Tourism, understood as the type of tourism that involves a visit to real or recreated places associated with death, suffering, misfortune, or the seemingly macabre, is not a new concept, even from a touristic point of view. In fact, places of war, disasters, death and atrocities always fascinated humans and are subject to visits. People have long been drawn, purposefully or otherwise, towards sites, attractions or events linked in one way or another with death, suffering, violence or disaster. The concept of dark tourism has been designed and studied for the last years and many are the destinations around the world where it has been implemented, playing an important role in both a country’s economy and its image. However, there is a gap in literature about this specific type of tourism. The main goal of this paper is to present a literature review about this new tourism product where the thrill seeking is the main motivation. Specifically, it’s our intent to present some Dark Tourism definitions, history and evolution, as well as, to introduce its typologies and identify the most important dark tourist sites all over the world.
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Having into consideration that we live in a multicultural society, it is important to analyse how far people view and accept each other. Therefore, one should reflect upon concepts such as: representations and stereotypes, because they are interpersonal constructs which are (re)built during the interaction of different sociocultural groups. In this study, we focus our attention on the representations a sociocultural group – Portuguese teachers - has of intercultural education and the role of teachers and educators in the promotion of an intercultural approach at school. We believe that teachers have the responsibility to: find out the representations students have of the Other; reconfigure stereotyped representations; and create representations which favor dialogue and relationship with the Other flourish. Following a sociolinguistic approach (Müller, 1998; Vasseur, 2001; Vasseur & Hudelot, 1998), which is related to the construction and diffusion of representations in discourse, we analyse the discourse of teachers during a workshop called ‘The Other and Myself’, in which they build and discuss about a didactic mask that portrays their own vision of both themselves and their ideas of intercultural education.
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Coincidence (e.g., of a statue and the piece of bronze which constitutes it) comes in two varieties – permanent and temporary. Moderate monism (about coincidence) is the position that permanent coincidence, but not temporary coincidence, entails identity. Extreme monism (also known as the stage theory) is the position that even temporary coincidence entails identity. Pluralists are opponents of monism tout court. The intuitively obvious, commonsensical position (= my own position) is moderate monism. It is therefore important to see if it can be sustained.
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We challenge 3 prevailing concepts in understanding atopic dermatitis using data from epidemiologic studies. First, we show that although atopy is associated with atopic dermatitis to some degree, its importance is not likely to be a simple causeand- effect relationship, especially at a population level. Our epidemiologic data do not exclude a contributory role for IgEmediated immunologic processes, especially in those with existing and severe disease. Second, evidence is presented that does not support a straightforward inverse relationship between infections and atopic dermatitis risk. A link, if present, is likely to be more complex, depending critically on the timing and type of infectious exposure. Third, recent evidence suggests that the risk of subsequent childhood asthma is not increased in children with early atopic dermatitis who are not also early wheezers, suggesting a comanifestation of phenotypes rather than a progressive atopic march. Collectively, these observations underline the importance of epidemiologic studies conducted at a population level to gain a more balanced understanding of the enigma of atopic dermatitis.
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Boecio introdujo cambios notables en la consideración de algunas nociones filosóficas y teológicas, en particular en las de «persona», «esencia» y «eternidad». Estudio la evolución de estas tres ideas, representadas en los textos objeto de análisis por palabras y expresiones como «personne», «créature humaine» o «éternel». Para hacerlo, interrogo desde perspectivas diversas –léxica, semántica, sintáctica y pragmática–, un corpus compuesto por obras de reflexión (tratados, cartas, memorias...) escritos en francés por mujeres entre los siglos XIV y XVIII.
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This study highlights the importance of cognition-affect interaction pathways in the construction of mathematical knowledge. Scientific output demands further research on the conceptual structure underlying such interaction aimed at coping with the high complexity of its interpretation. The paper discusses the effectiveness of using a dynamic model such as that outlined in the Mathematical Working Spaces (MWS) framework, in order to describe the interplay between cognition and affect in the transitions from instrumental to discursive geneses in geometrical reasoning. The results based on empirical data from a teaching experiment at a middle school show that the use of dynamic geometry software favours students’ attitudinal and volitional dimensions and helps them to maintain productive affective pathways, affording greater intellectual independence in mathematical work and interaction with the context that impact learning opportunities in geometric proofs. The reflective and heuristic dimensions of teacher mediation in students’ learning is crucial in the transition from instrumental to discursive genesis and working stability in the Instrumental-Discursive plane of MWS.
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Doutoramento em Gestão
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The present study provides a methodology that gives a predictive character the computer simulations based on detailed models of the geometry of a porous medium. We using the software FLUENT to investigate the flow of a viscous Newtonian fluid through a random fractal medium which simplifies a two-dimensional disordered porous medium representing a petroleum reservoir. This fractal model is formed by obstacles of various sizes, whose size distribution function follows a power law where exponent is defined as the fractal dimension of fractionation Dff of the model characterizing the process of fragmentation these obstacles. They are randomly disposed in a rectangular channel. The modeling process incorporates modern concepts, scaling laws, to analyze the influence of heterogeneity found in the fields of the porosity and of the permeability in such a way as to characterize the medium in terms of their fractal properties. This procedure allows numerically analyze the measurements of permeability k and the drag coefficient Cd proposed relationships, like power law, for these properties on various modeling schemes. The purpose of this research is to study the variability provided by these heterogeneities where the velocity field and other details of viscous fluid dynamics are obtained by solving numerically the continuity and Navier-Stokes equations at pore level and observe how the fractal dimension of fractionation of the model can affect their hydrodynamic properties. This study were considered two classes of models, models with constant porosity, MPC, and models with varying porosity, MPV. The results have allowed us to find numerical relationship between the permeability, drag coefficient and the fractal dimension of fractionation of the medium. Based on these numerical results we have proposed scaling relations and algebraic expressions involving the relevant parameters of the phenomenon. In this study analytical equations were determined for Dff depending on the geometrical parameters of the models. We also found a relation between the permeability and the drag coefficient which is inversely proportional to one another. As for the difference in behavior it is most striking in the classes of models MPV. That is, the fact that the porosity vary in these models is an additional factor that plays a significant role in flow analysis. Finally, the results proved satisfactory and consistent, which demonstrates the effectiveness of the referred methodology for all applications analyzed in this study.
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El presente trabajo revisa la bibliografía sobre gestión del riesgo (GRi) que ha aparecido en los últimos tiempos, intentando anclar sus nociones, recomendaciones, pautas y estándares al ámbito de las bibliotecas y centros de documentación e información. Se analiza su utilidad, realizando un balance sobre la bibliografía consultada, proveniente tanto de Argentina como de distintos países. Se concluye sobre la necesidad de aplicar los procesos y los estándares inherentes a la GRi a los de las unidades de información para evitar los peligros o las amenazas en distintos ámbitos tales como el financiero, comunicacional, tecnológico, humano, ambiental, entre otros
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The ontology engineering research community has focused for many years on supporting the creation, development and evolution of ontologies. Ontology forecasting, which aims at predicting semantic changes in an ontology, represents instead a new challenge. In this paper, we want to give a contribution to this novel endeavour by focusing on the task of forecasting semantic concepts in the research domain. Indeed, ontologies representing scientific disciplines contain only research topics that are already popular enough to be selected by human experts or automatic algorithms. They are thus unfit to support tasks which require the ability of describing and exploring the forefront of research, such as trend detection and horizon scanning. We address this issue by introducing the Semantic Innovation Forecast (SIF) model, which predicts new concepts of an ontology at time t + 1, using only data available at time t. Our approach relies on lexical innovation and adoption information extracted from historical data. We evaluated the SIF model on a very large dataset consisting of over one million scientific papers belonging to the Computer Science domain: the outcomes show that the proposed approach offers a competitive boost in mean average precision-at-ten compared to the baselines when forecasting over 5 years.
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Students may need explicit training in informal statistical reasoning in order to design experiments or use formal statistical tests effectively. By using scientific scandals and media misinterpretation, we can explore the need for good experimental design in an informal way. This article describes the use of a paper that reviews the measles mumps rubella vaccine and autism controversy in the UK to illustrate a number of threshold concepts underlying good study design and interpretation of scientific evidence. These include the necessity of sufficient sample size, representative and random sampling, appropriate controls and inferring causation.
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Subject ontogeny is the life of the subject in an indexing language (e.g., classification scheme like the DDC). Examining how a subject is treated over time tells us about the anatomy of an indexing language. For example, gypsies as a subject has been handled differently in different editions of the DDC.
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L’insertion dans un programme collégial, particulièrement celui des soins infirmiers, nécessite à l’individu d’utiliser efficacement, minimalement une stratégie d’apprentissage. Une proportion importante de la population étudiante présente des difficultés à trouver et à utiliser une telle stratégie favorisant cet apprentissage particulier. Pour résoudre ce défi, il est propice d’en expérimenter une et de questionner sa pertinence : L’utilisation du réseau de concepts comme stratégie semble-t-elle favoriser l’apprentissage, selon la perception des étudiantes et étudiants participants en soins infirmiers première session du Cégep Beauce-Appalaches? Le cadre de référence définit deux concepts importants de l’essai : « stratégie d’apprentissage » et « réseau de concepts. » Ce dernier est approfondi par rapport a) aux différentes appellations utilisées; b) aux utilités de celui-ci dans l’apprentissage et; c) au processus menant à la schématisation du réseau de concepts. Cela conduit aux objectifs spécifiques qui sont l’expérimentation, en milieu scolaire, du réseau de concepts comme stratégie d’apprentissage auprès d'étudiantes et étudiants inscrits au programme d’études soins infirmiers en première session du Cégep Beauce-Appalaches et la prise de connaissance de leurs perceptions par rapport à cette utilisation. Cette recherche-expérimentation appartient au pôle recherche. La méthodologie retenue est qualitative-interprétative et se réalise à l’aide d’un groupe-classe de 25 individus participants, d’une enseignante volontaire et du chercheur dans son rôle d’enseignant. L’expérimentation, en tenant compte de considérations éthiques et du processus menant à la schématisation du réseau de concepts, ainsi que l’utilisation d’outils de collecte des données élaborés et prétestés répondent aux objectifs spécifiques. Ces instruments de collectes des données sont des fiches évaluatives, un groupe de discussion et un journal de bord. Ils permettent l’identification des effets perçus de cette stratégie d’apprentissage, par les personnes participantes, lors de l’expérimentation. L’analyse des résultats s’effectue à partir de la codification des commentaires reçus dans les fiches évaluatives et à partir de rapports synthèses pour la section des énoncés utilisant l’échelle de Likert, ainsi que pour le journal de bord et pour le groupe de discussion. La présentation et l’interprétation des résultats obtenus permettent de dire qu’à de nombreuses reprises, les perceptions des participantes et participants, par rapport à l’utilisation du réseau de concepts, semblent favoriser l’apprentissage particulier requis dans le programme d’études soins infirmiers. La triangulation des résultats confirme que cette stratégie d’apprentissage semble favoriser a) la compréhension des relations entre les concepts principaux; b) la structuration des contenus pédagogiques pour l’étude; c) l’identification des concepts principaux; d) la compréhension de l’ensemble du contenu pédagogique concerné et; e) l’élaboration d’un résumé pédagogique. D’autre part, il est pertinent de mentionner que ces résultats correspondent aux écrits scientifiques constituant le cadre de référence de cet essai.
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La construction des chemins de fer portugais a eu, jusqu’en 1891, pour l’objectif principal de combler le retard économique du pays. Par suite de l’échec des entrepreneurs anglais, notamment Morton Petto, ce furent les hommes d’affaires et les capitaux qui jouèrent le rôle majeur, grâce notamment l’intervention des Pereire, puis celle de CIC, principal soutien des initiatives de l’entrepreneur espagnol D. José de Salamanca, enfin la Banque de Paris et des Pays-Bas et la Banque Ottomane. L’influence Saint-simonienne s’exerçait sur les ingénieurs formés à l’École Polytechnique de Lisbonne et bénéficiait la généralisation du modèle français de la concession. À partir des années 1890, ce système entra en crise, favorisant une influence allemand grandissante, tant en terme d’investissement qu’à travers la formation des ingénieurs, notamment ceux de l’Institut Supérieur Technique de Lisbonne, Le reflux des investissements étrangères, à partir de la crise de 1892, poussa l’État dans la voie de la nationalisation en 1899, dans qu’ensuite ne suisse survenir une relance de la construction ferroviaires. Après la Seconde Guerre mondial, les chemins de fer furent confiés à un unique exploitant national, la Compagnie des chemins de fer Portugais.