Crianças em risco:projecto de apoio sob os princípios da educação inclusiva

Ultrapassadas as concepções que apontavam como desejável a prévia classificação do aluno e a sua colocação em classes homogéneas, neste momento trabalha-se no sentido de desenvolver estratégias de inclusão baseadas em processos de educação sócio democráticos, para atender e responder adequadamente a crianças em risco de exclusão educativa e/ou social, no sentido de as incluir em classes heterogéneas. Foi com base neste princípio, que se desenvolveu o projecto, partindo da compreensão do trabalho desenvolvido numa IPSS, como Educadora de Infância, e na CPCJ, como membro da Comissão Restrita, para posteriormente delinear estratégias facilitadoras de inclusão e atendimento sócio democrático. Pertinentes para o trabalho de parceria, desenvolvido entre diversas entidades envolvidas neste projecto de investigação-acção. Com o trabalho de equipa foi possível proporcionar estratégias e encontrar soluções pertinentes no processo de inclusão e no desenvolvimento sócio pedagógico de crianças em risco em idade de creche, implementando assim um trabalho cooperativo entre as instituições, a família, a comunidade educativa e a comunidade local.

Águas pluviais: curvas IDF: Enquadramento no DR 23/95, de 23 de agosto

De acordo com o enquadramento nas normas regulamentares, do quadro jurídico português (DR 23 /95 de 23 de Agosto), aplicado ao estudo de águas pluviais, apresenta-se um desenvolvimento dos parâmetros de cálculo das três regiões pluviométricas a ter em consideração: A, B e C.Foram determinados os valores distintos e completos de ajustamento (a e b) das curvas IDF (intensidade /Duração /Frequência), até 60 minutos e para períodos de retorno até 100 anos, contemplando as 3 regiões homogéneas em causa. E consequentemente foram elaborados os quadros gráficos, com a visualização das curvas resultantes do tratamento e tradução dos valores estatísticos da função exponencial I= atb a ter em consideração e reproduzidos num gráfico decorrente da transformação da distribuição contínua de Gumbel.Ficam disponíveis os gráficos e os valores de apoio à determinação objectiva da Intensidade pluviométrica para todo o país, o que pode e pretende que venha a constituir mais uma ferramenta de apoio, nomeadamente para melhor se ajuizar dos caudais pluviais em escoamento urbanos.

Representaciones internas y externas de barrios negro/as en Quito y Cali: dos estudios de caso en Carapungo y El Retiro

Una de las consecuencias de la urbanización de las principales urbes latinoamericanas ha sido la formación de zonas catalogados como periféricas y marginales, lo cual ha terminado produciendo imaginarios sociales, donde una de sus principales características ha sido la representación de estos sectores como espacios del peligro, del espectáculo folclórico, la desorganización social y otra serie de imágenes construidas sobre ellos hasta el punto de haberse constituido en territorios estigmatizados. En esa medida, pensar las zonas periféricas en el contexto de la urbanización, conlleva necesariamente a considerar los modos como son imaginadas de acuerdo a las experiencias vividas en ellas y por variables sociodemográficas, raciales, de clase, de género y culturales que indican que la ciudad es un conglomerado social dividido geográfica y simbólicamente, en razón de estas adscripciones. Una de las poblaciones que se ha visto mayormente involucrada en dinámicas de concentración de zonas periféricas son los migrantes negro(as), tanto en Colombia1 como en el Ecuador, lo cual ha demarcado al interior de las ciudades procesos de racialización del espacio, debido a los vaivenes generados por la apropiación de la vivienda urbana, que ha determinado la formación de estas zonas con una alta concentración de población migrante. Precisamente, estos territorios urbanos -los barrios- de concentración de población negra, han cargado con el peso simbólico del estigma por parte de grupos sociales, instituciones y medios de comunicación, a través de representaciones estereotipadas que reproducen imágenes históricamente asociadas a los grupos y a los espacios de gente negra, tal como han sido las imágenes del crimen y visiones folclorizadas que enfatizan en una supuesta “naturalidad ontológica” sobre los modos de ser negro(a) y vivir las experiencias de negritud en los contextos donde se asientan estas poblaciones. De ahí, que al relacionar raza, migrantes y territorio he analizado las representaciones que sobre estos barrios periféricos se construyen interna y externamente, es decir, cómo son percibidos desde afuera, concretamente por los medios de comunicación (prensa) y cómo son representados por los propios migrantes negro(as) que habitan en ellos. Esta doble representación sobre los barrios de migrantes negro(as) constituye el “objeto” de estudio del presente trabajo. No se trata de comprender la ciudad como una totalidad, sino por el contrario, entender situaciones que pasan en ella, tal como son las dinámicas socioculturales de los barrios de concentración negra, a partir del ámbito de las prácticas representacionales. Así mismo, cabe anotar que he colocado énfasis en las representaciones “homogéneas”, más que en las diferentes representaciones que los mismos pobladores negro(as) elaboran sobre sus territorios, pues se intentó analizar como desde el interior de estos espacios se contrastan las representaciones externas.

Resignificación del mestizaje los dilemas de la identidad mestiza frente a la crisis del Estado Nación

Este estudio pretende hacer una relectura del mestizaje que vaya más allá de las interpretaciones dominantes que se han hecho sobre este fenómeno. Los discursos hegemónicos sobre el mestizaje han querido ver los intercruzamientos culturales como realidades homogéneas y armónicas. Sin embargo, el mestizaje, como expresión de la mezcla cultural, ha mostrado siempre su carácter ambivalente y contradictorio. En los espacios conflictivos que se producen por el choque de culturas el discurso hegemónico del mestizaje pierde legitimidad. Desde esos espacios plurales, que se encuentran en medio de dos o más realidades, se abre la posibilidad de reconocer las capacidades de negociación de los sujetos y las prácticas mestizas. En estos espacios fronterizos tanto las identidades como las culturas se están redefiniendo constantemente. Por estas razones, el mestizaje lejos de ser una realidad armónica es un fenómeno heterogéneo que muestra lo inesencial de las culturas y las identidades.

Modelling heterotachy in phylogenetic inference by reversible-jump Markov chain Monte Carlo

The rate at which a given site in a gene sequence alignment evolves over time may vary. This phenomenon-known as heterotachy-can bias or distort phylogenetic trees inferred from models of sequence evolution that assume rates of evolution are constant. Here, we describe a phylogenetic mixture model designed to accommodate heterotachy. The method sums the likelihood of the data at each site over more than one set of branch lengths on the same tree topology. A branch-length set that is best for one site may differ from the branch-length set that is best for some other site, thereby allowing different sites to have different rates of change throughout the tree. Because rate variation may not be present in all branches, we use a reversible-jump Markov chain Monte Carlo algorithm to identify those branches in which reliable amounts of heterotachy occur. We implement the method in combination with our 'pattern-heterogeneity' mixture model, applying it to simulated data and five published datasets. We find that complex evolutionary signals of heterotachy are routinely present over and above variation in the rate or pattern of evolution across sites, that the reversible-jump method requires far fewer parameters than conventional mixture models to describe it, and serves to identify the regions of the tree in which heterotachy is most pronounced. The reversible-jump procedure also removes the need for a posteriori tests of 'significance' such as the Akaike or Bayesian information criterion tests, or Bayes factors. Heterotachy has important consequences for the correct reconstruction of phylogenies as well as for tests of hypotheses that rely on accurate branch-length information. These include molecular clocks, analyses of tempo and mode of evolution, comparative studies and ancestral state reconstruction. The model is available from the authors' website, and can be used for the analysis of both nucleotide and morphological data.

Inference on microsatellite mutation processes in the invasive mite, Varroa destructor, using reversible jump Markov chain Monte Carlo

Varroa destructor is a parasitic mite of the Eastern honeybee Apis cerana. Fifty years ago, two distinct evolutionary lineages (Korean and Japanese) invaded the Western honeybee Apis mellifera. This haplo-diploid parasite species reproduces mainly through brother sister matings, a system which largely favors the fixation of new mutations. In a worldwide sample of 225 individuals from 21 locations collected on Western honeybees and analyzed at 19 microsatellite loci, a series of de novo mutations was observed. Using historical data concerning the invasion, this original biological system has been exploited to compare three mutation models with allele size constraints for microsatellite markers: stepwise (SMM) and generalized (GSM) mutation models, and a model with mutation rate increasing exponentially with microsatellite length (ESM). Posterior probabilities of the three models have been estimated for each locus individually using reversible jump Markov Chain Monte Carlo. The relative support of each model varies widely among loci, but the GSM is the only model that always receives at least 9% support, whatever the locus. The analysis also provides robust estimates of mutation parameters for each locus and of the divergence time of the two invasive lineages (67,000 generations with a 90% credibility interval of 35,000-174,000). With an average of 10 generations per year, this divergence time fits with the last post-glacial Korea Japan land separation. (c) 2005 Elsevier Inc. All rights reserved.

Bayesian analysis of correlated evolution of discrete characters by reversible-jump Markov chain Monte Carlo

We describe a Bayesian method for investigating correlated evolution of discrete binary traits on phylogenetic trees. The method fits a continuous-time Markov model to a pair of traits, seeking the best fitting models that describe their joint evolution on a phylogeny. We employ the methodology of reversible-jump ( RJ) Markov chain Monte Carlo to search among the large number of possible models, some of which conform to independent evolution of the two traits, others to correlated evolution. The RJ Markov chain visits these models in proportion to their posterior probabilities, thereby directly estimating the support for the hypothesis of correlated evolution. In addition, the RJ Markov chain simultaneously estimates the posterior distributions of the rate parameters of the model of trait evolution. These posterior distributions can be used to test among alternative evolutionary scenarios to explain the observed data. All results are integrated over a sample of phylogenetic trees to account for phylogenetic uncertainty. We implement the method in a program called RJ Discrete and illustrate it by analyzing the question of whether mating system and advertisement of estrus by females have coevolved in the Old World monkeys and great apes.

Detecting recombination in 4-taxa DNA sequence alignments with Bayesian hidden Markov models and Markov chain Monte Carlo

This article presents a statistical method for detecting recombination in DNA sequence alignments, which is based on combining two probabilistic graphical models: (1) a taxon graph (phylogenetic tree) representing the relationship between the taxa, and (2) a site graph (hidden Markov model) representing interactions between different sites in the DNA sequence alignments. We adopt a Bayesian approach and sample the parameters of the model from the posterior distribution with Markov chain Monte Carlo, using a Metropolis-Hastings and Gibbs-within-Gibbs scheme. The proposed method is tested on various synthetic and real-world DNA sequence alignments, and we compare its performance with the established detection methods RECPARS, PLATO, and TOPAL, as well as with two alternative parameter estimation schemes.

Estimation of Hidden Markov Models parameters using differential evolution

Hidden Markov Models (HMMs) have been successfully applied to different modelling and classification problems from different areas over the recent years. An important step in using HMMs is the initialisation of the parameters of the model as the subsequent learning of HMM’s parameters will be dependent on these values. This initialisation should take into account the knowledge about the addressed problem and also optimisation techniques to estimate the best initial parameters given a cost function, and consequently, to estimate the best log-likelihood. This paper proposes the initialisation of Hidden Markov Models parameters using the optimisation algorithm Differential Evolution with the aim to obtain the best log-likelihood.

Enhancing change detection in low-quality surveillance footage using markov random fields

Urban surveillance footage can be of poor quality, partly due to the low quality of the camera and partly due to harsh lighting and heavily reflective scenes. For some computer surveillance tasks very simple change detection is adequate, but sometimes a more detailed change detection mask is desirable, eg, for accurately tracking identity when faced with multiple interacting individuals and in pose-based behaviour recognition. We present a novel technique for enhancing a low-quality change detection into a better segmentation using an image combing estimator in an MRF based model.

Robustness and applicability of Markov chain Monte Carlo algorithms for eigenvalue problems

In this paper we analyse applicability and robustness of Markov chain Monte Carlo algorithms for eigenvalue problems. We restrict our consideration to real symmetric matrices. Almost Optimal Monte Carlo (MAO) algorithms for solving eigenvalue problems are formulated. Results for the structure of both - systematic and probability error are presented. It is shown that the values of both errors can be controlled independently by different algorithmic parameters. The results present how the systematic error depends on the matrix spectrum. The analysis of the probability error is presented. It shows that the close (in some sense) the matrix under consideration is to the stochastic matrix the smaller is this error. Sufficient conditions for constructing robust and interpolation Monte Carlo algorithms are obtained. For stochastic matrices an interpolation Monte Carlo algorithm is constructed. A number of numerical tests for large symmetric dense matrices are performed in order to study experimentally the dependence of the systematic error from the structure of matrix spectrum. We also study how the probability error depends on the balancing of the matrix. (c) 2007 Elsevier Inc. All rights reserved.

Measuring departures from Hardy-Weinberg: a Markov chain Monte Carlo method for estimating the inbreeding coefficient

Many well-established statistical methods in genetics were developed in a climate of severe constraints on computational power. Recent advances in simulation methodology now bring modern, flexible statistical methods within the reach of scientists having access to a desktop workstation. We illustrate the potential advantages now available by considering the problem of assessing departures from Hardy-Weinberg (HW) equilibrium. Several hypothesis tests of HW have been established, as well as a variety of point estimation methods for the parameter which measures departures from HW under the inbreeding model. We propose a computational, Bayesian method for assessing departures from HW, which has a number of important advantages over existing approaches. The method incorporates the effects-of uncertainty about the nuisance parameters--the allele frequencies--as well as the boundary constraints on f (which are functions of the nuisance parameters). Results are naturally presented visually, exploiting the graphics capabilities of modern computer environments to allow straightforward interpretation. Perhaps most importantly, the method is founded on a flexible, likelihood-based modelling framework, which can incorporate the inbreeding model if appropriate, but also allows the assumptions of the model to he investigated and, if necessary, relaxed. Under appropriate conditions, information can be shared across loci and, possibly, across populations, leading to more precise estimation. The advantages of the method are illustrated by application both to simulated data and to data analysed by alternative methods in the recent literature.