1,422 research outputs found
Desenvolvimento de interacções pessoais na construção de blogues no âmbito da disciplina de biologia/geologia : um estudo preliminar
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
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
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
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
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
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
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
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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