1,408 research outputs found

    Desenvolvimento de interacções pessoais na construção de blogues no âmbito da disciplina de biologia/geologia : um estudo preliminar

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    Este documento apresenta resultados preliminares de um estudo de caso desenvolvido no âmbito do Doutoramento em Didáctica das Ciências, onde se utilizaram as tecnologias informáticas em contexto educativo, numa turma do Ensino Secundário. O projecto desenvolvido propôs-se analisar a utilização de blogues como complemento nas aprendizagens em Biologia/Geologia, com enfoque nas CTSA. Pretendeu ainda analisar como se construíram as relações interpessoais entre os membros do projecto, realizado com recurso a trabalho de grupo. Estratégias que envolvam as chamadas “novas tecnologias” são importantes na Educação dos jovens para a sociedade actual também conhecida por “sociedade do conhecimento”

    The Bayesian Origins of Growth Rates in Stochastic Environments

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    Stochastic multiplicative dynamics characterize many complex natural phenomena such as selection and mutation in evolving populations, and the generation and distribution of wealth within social systems. Population heterogeneity in stochastic growth rates has been shown to be the critical driver of diversity dynamics and of the emergence of wealth inequality over long time scales. However, we still lack a general statistical framework that systematically explains the origins of these heterogeneities from the adaptation of agents to their environment. In this paper, we derive population growth parameters resulting from the interaction between agents and their knowable environment, conditional on subjective signals each agent receives. We show that average growth rates converge, under specific conditions, to their maximal value as the mutual information between the agent's signal and the environment, and that sequential Bayesian learning is the optimal strategy for reaching this maximum. It follows that when all agents access the same environment using the same inference model, the learning process dynamically attenuates growth rate disparities, reversing the long-term effects of heterogeneity on inequality. Our approach lays the foundation for a unified general quantitative modeling of social and biological phenomena such as the dynamical effects of cooperation, and the effects of education on life history choices.Comment: 12 pages, 4 figure

    Identification of functional information subgraphs in complex networks

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    We present a general information theoretic approach for identifying functional subgraphs in complex networks where the dynamics of each node are observable. We show that the uncertainty in the state of each node can be expressed as a sum of information quantities involving a growing number of correlated variables at other nodes. We demonstrate that each term in this sum is generated by successively conditioning mutual informations on new measured variables, in a way analogous to a discrete differential calculus. The analogy to a Taylor series suggests efficient search algorithms for determining the state of a target variable in terms of functional groups of other degrees of freedom. We apply this methodology to electrophysiological recordings of networks of cortical neurons grown it in vitro. Despite strong stochasticity, we show that each cell's patterns of firing are generally explained by the activity of a small number of other neurons. We identify these neuronal subgraphs in terms of their mutually redundant or synergetic character and reconstruct neuronal circuits that account for the state of each target cell.Comment: 4 pages, 4 figure

    Neonatal Morbi-Mortality in Very Low Birth Weight in Europe: the Portuguese Experience

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    The aim of this study was to access evolution in care of very low birth weight (VLBW) infants after the implementation of a regionalization policy in Portugal. The data of the National Portuguese Network of VLBW infants are analyzed concerning mortality, morbidity, and quality of regionalization. A total of 12,826 VLBW infants born from 1 January 1994 to 31 December 2008 were enrolled, with a prevalence of 0.66%-0.99% of all live born. The global mortality was 11%. The major improvement in survival is in the babies more than 1000 g. Since 2004, the threshold of viability is 25 weeks, but the intact survival is around 28 weeks. In the last 10 years with more efficient regionalization more VLBW babies are born in the right place. The improvement in neonatal mortality rate was determinant in the good evolution of perinatal and infant mortalities. After reinforcement of regionalization policies, we found improvements in mortality for VLBW infants. The aims of regionalization were achieved. The reform of perinatal care in Portugal is an example of how a good diagnosis and adequate proposals combined with a strong political will is crucial for changing.info:eu-repo/semantics/publishedVersio

    Intralobar Bronchopulmonary Sequestration with Associated Cardiac Malformation

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    O sequestro pulmonar intralobar geralmente não está associado a outras anomalias congénitas. Apresenta-se o caso clínico de um recém-nascido com diagnóstico pré-natal de anomalia pulmonar com desvio do mediastino,a quem foi diagnosticada uma coartação da aorta ao quinto dia de vida. A tomografia computorizada torácica revelou uma massa sólida na região basal posterior do lobo inferior esquerdo, sugerindo poder corresponder a um sequestro pulmonar intralobar. Foi submetido a cirurgia de correção da coartação da aorta e de ressecção do segmento correspondente de sequestro pulmonar.O exame anatomopatológico confirmou o diagnóstico de sequestro pulmonar intralobar. À data da redação deste trabalho, a criança tinha quatro anos de idade e estava clinicamente bem. O caso ilustra a associação de sequestro pulmonar intralobar a uma malformação cardíaca

    Information Synergy Maximizes the Growth Rate of Heterogeneous Groups

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    Collective action and group formation are fundamental behaviors among both organisms cooperating to maximize their fitness, and people forming socioeconomic organizations. Researchers have extensively explored social interaction structures via game theory and homophilic linkages, such as in kin selection and scalar stress, to understand emergent cooperation in complex systems. However, we still lack a general theory capable of predicting how agents benefit from heterogeneous preferences, joint information, or skill complementarities in statistical environments. Here, we derive a general statistical dynamics for the origin of cooperation based on the management of resources and pooled information. Specifically, we show how groups that optimally combine complementary agent knowledge about resources in statistical environments maximize their growth rate. We show that these advantages are quantified by the information synergy embedded in the conditional probability of environmental states given agents' signals, such that groups with greater diversity of signals maximize their collective information. It follows that, when there are constraints placed on group formation, agents must intelligently select with who they cooperate with to maximize the synergy available to their own signal. Our results show how the general properties of information underlie the optimal collective formation and dynamics of groups of heterogeneous agents across social and biological phenomena.Comment: 14 pages, 4 figure

    The rock carvings of Bouça da Cova da Moura (Ardegães, Maia, Northern Portugal) in the context of Late Prehistory in the Leça basin

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    Este texto pretende dar a conhecer o conjunto de gravuras rupestres da Bouça da Cova da Moura. A análise efetuada ao conjunto de signos permitiu denotar, a presença de composições gráficas pertencentes à tradição artística que se convencionou denominar de arte atlântica, representações de cariz mais esquemático e motivos de época histórica. Na envolvência dos afloramentos gravados descobriram-se monumentos megalíticos, áreas de dispersão de materiais cerâmicos datáveis do Calcolítico, uma ocupação da Idade do Bronze, além de materiais dispersos deste período genérico, relevantes para a análise da biografia deste lugar numa pequena escala de análise. A inserção deste locus numa escala mais ampla de análise, ou seja, os Montes do Leandro, pequeno contraforte da serra do Bougado, permite admitir que este complexo de gravuras rupestres faria parte de um vasto território de ampla significação simbólica durante a Pré-história Recente. Neste sentido as diferentes materialidades seriam, resultado de um processo aditivo que resulta da frequência do planalto, da sua da reutilização e reinterpretação, num templo cíclico.The aim of this paper is to offer an overview of the rock art assemblage at Bouça da Cova da Moura in its local and regional contexts. The site is located in Ardegães, parish of Águas Santas, municipality of Maia, district of Porto, in north-western Portugal. Fieldwork carried out in the end of the 20th century and the beginning of the 21st century, resulted in the discovery of new carved surfaces in the place where the well-known ‘pedra partida de Ardegães’ had been found; it was not only possible to unveil aspects related to its topographical context but also to discover other materialities which are spatially related to the rock carvings. Stylistic analysis undertaken to the set of carvings allow us to consider that we are beyond an assemblage which is partly constituted of rock art compositions belonging to the prehistoric art tradition conventionally called atlantic art, there is one schematic human figure and other motifs that belong to historical periods. In the vicinities of the carved outcrops there are megalithic monuments dated to the Neolithic, scatters of pottery fragments probably dated to the Copper Age, evidence for a Bronze Age occupation site, as well as clusters of surface finds from the same period. Overall, the field data recovered so far is extremely relevant for the analysis of the biography of this place at a small scale of analysis. The integration of this locus in a wider spatial scale, i.e. in the plateau that cuts across the territory in the north-south direction linking it to the Bougado hills, allow us to admit that this rock art complex would be part of a vast territory of symbolic significance in Late Prehistory. Thus, the distinct archaeological remains may be the materialisation of the importance of this geomorphological unit in the cognitive map and ideological universe of the prehistoric communities who dwelled, over a long period of time, along the middle basin of the River Neiva. These different materialities would result from a process of addition in the occupation of the plateau, of its reuse and reinterpretation in a cyclical time.Este texto insere-se no projeto Bronze Age Landscapes in the west of Iberian Peninsula / Paisagens da Idade do Bronze no ocidente peninsular (SFRH/BSAB/ 986/10) apoiado e financiado pela FCT no âmbito de uma Bolsa de Licença Sabática.info:eu-repo/semantics/publishedVersio

    The contribution of DNA methylation to the (dys)function of oligodendroglia in neurodegeneration

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    Neurodegenerative diseases encompass a heterogeneous group of conditions characterised by the progressive degeneration of the structure and function of the central or peripheral nervous systems. The pathogenic mechanisms underlying these diseases are not fully understood. However, a central feature consists of regional aggregation of proteins in the brain, such as the accumulation of β-amyloid plaques in Alzheimer’s disease (AD), inclusions of hyperphosphorylated microtubule-binding tau in AD and other tauopathies, or inclusions containing α-synuclein in Parkinson’s disease (PD), dementia with Lewy bodies (DLB) and multiple system atrophy (MSA). Various pathogenic mechanisms are thought to contribute to disease, and an increasing number of studies implicate dysfunction of oligodendrocytes (the myelin producing cells of the central nervous system) and myelin loss. Aberrant DNA methylation, the most widely studied epigenetic modification, has been associated with many neurodegenerative diseases, including AD, PD, DLB and MSA, and recent findings highlight aberrant DNA methylation in oligodendrocyte/myelin-related genes. Here we briefly review the evidence showing that changes to oligodendrocytes and myelin are key in neurodegeneration, and explore the relevance of DNA methylation in oligodendrocyte (dys)function. As DNA methylation is reversible, elucidating its involvement in pathogenic mechanisms of neurodegenerative diseases and in dysfunction of specific cell-types such as oligodendrocytes may bring opportunities for therapeutic interventions for these diseases
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