Self-interacting scalar field cosmologies: unified exact solutions and symmetries

We investigate a mechanism that generates exact solutions of scalar field cosmologies in a unified way. The procedure investigated here permits to recover almost all known solutions, and allows one to derive new solutions as well. In particular, we derive and discuss one novel solution defined in terms of the Lambert function. The solutions are organised in a classification which depends on the choice of a generating function which we have denoted by x(phi) that reflects the underlying thermodynamics of the model. We also analyse and discuss the existence of form-invariance dualities between solutions. A general way of defining the latter in an appropriate fashion for scalar fields is put forward.

Equilibrium self-assembly of colloids with distinct interaction sites: Thermodynamics, percolation, and cluster distribution functions

We calculate the equilibrium thermodynamic properties, percolation threshold, and cluster distribution functions for a model of associating colloids, which consists of hard spherical particles having on their surfaces three short-ranged attractive sites (sticky spots) of two different types, A and B. The thermodynamic properties are calculated using Wertheim's perturbation theory of associating fluids. This also allows us to find the onset of self-assembly, which can be quantified by the maxima of the specific heat at constant volume. The percolation threshold is derived, under the no-loop assumption, for the correlated bond model: In all cases it is two percolated phases that become identical at a critical point, when one exists. Finally, the cluster size distributions are calculated by mapping the model onto an effective model, characterized by a-state-dependent-functionality (f) over bar and unique bonding probability (p) over bar. The mapping is based on the asymptotic limit of the cluster distributions functions of the generic model and the effective parameters are defined through the requirement that the equilibrium cluster distributions of the true and effective models have the same number-averaged and weight-averaged sizes at all densities and temperatures. We also study the model numerically in the case where BB interactions are missing. In this limit, AB bonds either provide branching between A-chains (Y-junctions) if epsilon(AB)/epsilon(AA) is small, or drive the formation of a hyperbranched polymer if epsilon(AB)/epsilon(AA) is large. We find that the theoretical predictions describe quite accurately the numerical data, especially in the region where Y-junctions are present. There is fairly good agreement between theoretical and numerical results both for the thermodynamic (number of bonds and phase coexistence) and the connectivity properties of the model (cluster size distributions and percolation locus).

Low Complexity Intra Mode Selection for Efficient Distributed Video Coding

Motion compensated frame interpolation (MCFI) is one of the most efficient solutions to generate side information (SI) in the context of distributed video coding. However, it creates SI with rather significant motion compensated errors for some frame regions while rather small for some other regions depending on the video content. In this paper, a low complexity Infra mode selection algorithm is proposed to select the most 'critical' blocks in the WZ frame and help the decoder with some reliable data for those blocks. For each block, the novel coding mode selection algorithm estimates the encoding rate for the Intra based and WZ coding modes and determines the best coding mode while maintaining a low encoder complexity. The proposed solution is evaluated in terms of rate-distortion performance with improvements up to 1.2 dB regarding a WZ coding mode only solution.

Application of GIS-based multi-criteria analysis for site selection of aquifer recharge with reclaimed water

Reclaimed water from small wastewater treatment facilities in the rural areas of the Beira Interior region (Portugal) may constitute an alternative water source for aquifer recharge. A 21-month monitoring period in a constructed wetland treatment system has shown that 21,500 m(3) year(-1) of treated wastewater (reclaimed water) could be used for aquifer recharge. A GIS-based multi-criteria analysis was performed, combining ten thematic maps and economic, environmental and technical criteria, in order to produce a suitability map for the location of sites for reclaimed water infiltration. The areas chosen for aquifer recharge with infiltration basins are mainly composed of anthrosol with more than 1 m deep and fine sand texture, which allows an average infiltration velocity of up to 1 m d(-1). These characteristics will provide a final polishing treatment of the reclaimed water after infiltration (soil aquifer treatment (SAT)), suitable for the removal of the residual load (trace organics, nutrients, heavy metals and pathogens). The risk of groundwater contamination is low since the water table in the anthrosol areas ranges from 10 m to 50 m. Oil the other hand, these depths allow a guaranteed unsaturated area suitable for SAT. An area of 13,944 ha was selected for study, but only 1607 ha are suitable for reclaimed water infiltration. Approximately 1280 m(2) were considered enough to set up 4 infiltration basins to work in flooding and drying cycles.

Viability of Two New Mixture Design Methodologies for Self-Consolidating Concrete

This paper presents the results from an experimental study of the technical viability of two mixture designs for self-consolidating concrete (SCC) proposed by two Portuguese researchers in a previous work. The objective was to find the best method to provide the required characteristics of SCC in fresh and hardened states without having to experiment with a large number of mixtures. Five SCC mixtures, each with a volume of 25 L (6.61 gal.) were prepared using a forced mixer with a vertical axis for each of three compressive strength targets: 40, 55, and 70 MPa (5.80, 7.98, and 10.15 ksi). The mixtures' fresh state properties of fluidity, segregation resistance ability, and bleeding and blockage tendency, and their hardened state property of compressive strength were compared. For this study, the following tests were performed. slump-flow, V-funnel, L-box, box, and compressive strength. The results of this study made it possible to identify the most influential factors in the design of the SCC mixtures.

Avaliação do perfil hemodinâmico de válvulas aórticas percutâneas: análise comparativa entre os dois dispositivos disponíveis no mercado - válvula auto-expansível e válvula expansível por balão

Mestrado em Tecnologia de Diagnóstico e Intervenção Cardiovascular. Área de especialização: Intervenção Cardiovascular.

: SiC Multilayer Photonic Structures with Self Optical Bias Amplification

Characteristics of tunable wavelength pi'n/pin filters based on a-SiC:H multilayered stacked cells are studied both experimental and theoretically. Results show that the device combines the demultiplexing operation with the simultaneous photodetection and self amplification of the signal. An algorithm to decode the multiplex signal is established. A capacitive active band-pass filter model is presented and supported by an electrical simulation of the state variable filter circuit. Experimental and simulated results show that the device acts as a state variable filter. It combines the properties of active high-pass and low-pass filter sections into a capacitive active band-pass filter using a changing photo capacitance to control the power delivered to the load.

As conceções e as práticas dos gestores de topo na escola pública e privada : convergências e divergências

O papel crucial da escola na sociedade e o exercício da atividade profissional como docente, com um olhar atento sobre o traçar das políticas educativas, motivou a elaboração deste trabalho de investigação, que tem como objeto de estudo os papéis desempenhados pelos diretores das escolas estatais e não estatais e como objetivos específicos estudar o impacto da legislação emanada pela tutela, nas escolas públicas e privadas e analisar as convergências e divergências nas conceções e práticas dos seus diretores. As dimensões analíticas exploradas no estudo abrangem as conceções gestionárias dos diretores quanto aos modelos de gestão, às práticas de autonomia, ao serviço educativo e à prestação de contas. Este trabalho de natureza qualitativa foca o olhar sobre um grupo restrito de atores educativos que foram escolhidos devido ao papel que desempenham na organização educativa e porque a publicação do Decreto- Lei 75/ 2008 de 22 de abril, trouxe alterações à escola pública. A tradição de direção colegial que vigorava nas organizações educativas estatais foi quebrada. O presidente do conselho diretivo é doravante substituído pelo diretor que passa a delegar competências, a designar equipas e a prestar contas à tutela e comunidade educativa à semelhança do diretor da escola privada. O estudo de caso apresentado foi realizado em três escolas públicas e em três colégios privados com recurso a entrevistas semiestruturadas e à análise documental. As conclusões deste trabalho remetem para a existência de muitos pontos de convergência entre a opinião dos diretores da escola pública e privada. As temáticas relativas à autonomia, escolha do pessoal docente e prestação de contas, são olhadas pela mesma perspetiva. A autonomia é vista como “uma miragem”; uma “terra prometida” (Lima e Afonso, 1995). A prestação de contas é exigida aos diretores do ensino estatal e do privado através de instrumentos próximos. As principais divergências situam-se ao nível do menor interesse demonstrado, por parte da direção da escola privada, pela oferta de cursos profissionais e pelo menor investimento em estratégias para a prevenção do abandono escolar, que é considerado pouco significativo na escola não estatal. A defesa da escolha de escola e da modalidade de cheque ensino são outros dos pontos que marcam a divergência entre estes diretores. Abstract: This investigative paper - whose objective is the study of the role of the school directors, both State and non-state, and the impact of legislation on both State and private schools, as well as the analysis of the convergent and divergent conceptions and practices of these directors – is motivated by the crucial role played by schools in our society and by the professional activity of the teacher, with an attentive look at the educational practices. The analytical dimension explored in this study includes the various concepts of management of the school director as models of management, as well as practices in self-sufficiency, budget control and educational service to the community. This study has a qualitative nature and focuses on a small group of individuals who were chosen for the role they play in the whole educational structure, considering that the Decree nº 75/2008, published on April the 22nd, determined alterations to the public school system. The traditional method of control of the public school system has, henceforth, been changed. The headmaster is now substituted by a director who delegates his functions, makes up work teams and elaborates the school budget which is presented to the respective governmental ministry and the community, much like as what happens in private schools. The present study encompasses three public schools and three private schools, the methods of study being semi-structured interviews as well as the consultation of documentation. The conclusions point to many convergent opinions of the school directors of both the public and the private sector. The school directors of both public and private schools used in this study share the same opinion as to the factors involved in the selection of teachers, the elaboration of the school budget and the implementation of self-sufficiency policies. These self-sufficiency policies are seen as a “mirage” or a “promised land” (Lima and Afonso, 1995). The school budget and its management practices are implemented in both public and private schools through similar instruments. The principal differences are noted on smaller, less interesting points, on the part of the direction of the private schools, and result from the elaboration of professional courses and minor investment in the strategies, oriented to the prevention of school drop-outs, which is considered of little significance in the private school sector. The other factors of divergence result from the right to choose the type of school desired and the type of teaching implemented.

O papel da supervisão na avaliação de desempenho docente

Com as várias reformulações do processo de avaliação de desempenho docente (ADD), passou-se de um processo de avaliação dos professores assente na autoavaliação do docente, para um sistema de heteroavaliação que visa a prestação de contas e a seleção, mas também a melhoria de práticas e o desenvolvimento profissional, através do acompanhamento supervisivo. No entanto, a conciliação entre estas duas perspetivas não é fácil e tem gerado perplexidades e inquietações entre os avaliadores e entre os avaliados. Com este estudo, pretendemos conhecer a perspetiva de avaliadores e avaliados sobre o papel que a Supervisão detém no processo de avaliação de desempenho do professor e o seu contributo para o desenvolvimento profissional do professor e melhoria das práticas. Assim desenhou-se um plano de estudo qualitativo, exploratório e descritivo procurando captar o ponto de vista dos principais intervenientes no processo. O principal meio de recolha de dados foi a entrevista semiestruturada a 4 professores avaliadores e 4 professores avaliados do Departamento de Matemática e Ciências Experimentais de um Agrupamento de Escolas. Os resultados mostram que os docentes discordam do modelo de ADD, mas que o processo vivenciado teve caraterísticas positivas, dando os avaliadores especial relevância à oportunidade de conhecer outros processos de trabalho, a partir da observação de aulas. Avaliadores e avaliados referem ainda o bom relacionamento estabelecido entre ambos, contradizendo as preocupações expressas quando se pronunciaram sobre os problemas do modelo de avaliação. No entanto, ambos os subgrupos focam a falta de formação e qualificação profissional dos avaliadores. Em termos gerais, é possível concluir que a maior parte das dificuldades atribuídas pelos docentes ao modelo de ADD não foi depois sentida na implementação prática. Por outro lado, na opinião dos docentes, o processo experienciado não teve verdadeiro impacto na melhoria das práticas ou no desenvolvimento profissional dos docentes envolvidos. - Abstract The several reformulations of the process of the teacher performance evaluation made the process of evaluating teachers, which was first based on a self-evaluation change into a straight assessment system, which aims not only accountability and selection, but also the improvement of the practice and professional development through the supervision of the teaching practice. However, the conciliation between these perspectives has not been easy and has generated anxieties and perplexities among evaluators and evaluated. With this study we intend to know the perspective of the evaluators and of the evaluated concerning the role supervision has hold in the process of evaluating a teacher’s performance and its contribution to the professional development of the teacher and to the improvement of his practices. Thus, a qualitative, exploratory and descriptive study plan was drawn to get to know the viewpoint of the intervening ones in the process. The main means for data collection was based on a semi structured interview, targeting 4 teacher evaluators and 4 evaluated teachers of the Experimental Sciences and Mathematics Department of a group of Schools. The results show that teachers disagree with the teacher’s evaluation model, but the experienced process had positive characteristics. Besides, evaluators have given special relevance to the opportunity of getting to know other working methods thanks to the lessons’ observations. Evaluators and evaluated also refer the good relationship between both parts contradicting the fears they had when they first pronounced themselves about this evaluation model. However, both subgroups focus the lack of training and professional qualifications of the evaluators. So it’s possible to conclude that most worries mentioned by the teachers when referring to this model of teacher performance evaluation were not verified during its practical implementation. On the other hand, in the opinion of the involved teachers, the experienced process had no real impact on their practice improvement or on their professional development.

Communication: The criticality of self-assembled rigid rods on triangular lattices

The criticality of self-assembled rigid rods on triangular lattices is investigated using Monte Carlo simulation. We find a continuous transition between an ordered phase, where the rods are oriented along one of the three (equivalent) lattice directions, and a disordered one. We conclude that equilibrium polydispersity of the rod lengths does not affect the critical behavior, as we found that the criticality is the same as that of monodisperse rodson the same lattice, in contrast with the results of recently published work on similar models. (C) 2011 American Institute of Physics. [doi:10.1063/1.3556665]

Reconfigurable SiC Embedded Photonic Structures with Self Optical Bias Control

Multilayered heterostructures based on embedded a-Si:H and a-SiC:H p-i-n filters are analyzed from differential voltage design perspective using short- and long-pass filters. The transfer functions characteristics are presented. A numerical simulation is presented to explain the filtering properties of the photonic devices. Several monochromatic pulsed lights, separately (input channels) or in a polychromatic mixture (multiplexed signal) at different bit rates, illuminated the device. Steady-state optical bias is superimposed from the front and the back side. Results show that depending on the wavelength of the external background and impinging side, the device acts either as a short- or a long-pass band filter or as a band-stop filter. Particular attention is given to the amplification coefficient weights, which allow to take into account the wavelength background effects when a band or frequency needs to be filtered or the gate switch, in which optical active filter gates are used to select and filter input signals to specific output ports in wavelength division multiplexing (WDM) communication systems. This nonlinearity provides the possibility for selective removal or addition of wavelengths. A truth table of an encoder that performs 8-to-1 MUX function exemplifies the optoelectronic conversion.

Self-assembly in chains, rings, and branches: a single component system with two critical points

Agências financiadoras: FCT - PEstOE/FIS/UI0618/2011; PTDC/FIS/098254/2008 ERC-PATCHYCOLLOIDS e MIUR-PRIN

Feature selection for clustering categorical data with an embedded modelling approach

Research on the problem of feature selection for clustering continues to develop. This is a challenging task, mainly due to the absence of class labels to guide the search for relevant features. Categorical feature selection for clustering has rarely been addressed in the literature, with most of the proposed approaches having focused on numerical data. In this work, we propose an approach to simultaneously cluster categorical data and select a subset of relevant features. Our approach is based on a modification of a finite mixture model (of multinomial distributions), where a set of latent variables indicate the relevance of each feature. To estimate the model parameters, we implement a variant of the expectation-maximization algorithm that simultaneously selects the subset of relevant features, using a minimum message length criterion. The proposed approach compares favourably with two baseline methods: a filter based on an entropy measure and a wrapper based on mutual information. The results obtained on synthetic data illustrate the ability of the proposed expectation-maximization method to recover ground truth. An application to real data, referred to official statistics, shows its usefulness.

East of Suez and the imaginary tangles of space and self

Drawing on postcolonial studies and the theorization on imperial gothic, this paper centres on three texts: The Hosts of the Lord (1900) by Flora Annie Steel; East of Suez (1901) by Alice Perrin, and The Way of an Eagle (1912)by Ethel Dell. These three texts highlight in different ways the discursive mediation of the Other and its destabilizing effects on the identity of the European-minded colonizer, thus foregrounding the multifarious nature of the British imaginative engagement with India. In this context, it is particularly relevant to examine the political and ideological implications of representing anywhere East of Suez as a locus of primitivism and chaos vis-à-vis the colonizer’s ambivalent reactions. Thus we seek to demonstrate the power of two distinct practices or modes of representation – namely, the power of a metaphorical discourse versus metonymic discourse- within the proces of constructing the East for a vast Western readership.

Psychological well-being and perception of disease severity in people with multiple sclerosis, who underwent a program of self-regulation to promote physical activity

Rehabilitation is very important for in the results of treatment in individuals with multiple sclerosis. Rehabilitation processes occur through gradual changes. These changes integrate intrinsic and extrinsic mechanisms of the individual, promoting adaptations to the needs and activities of daily living according to individual goals. Recommendations for exercise in multiple sclerosis: these recommendations apply only to patients with EDSS less than 7; moderate intensity aerobic exercise for a total of 20 to 30 minutes, twice or three times for week; the resistance training with low or moderate intensity is well tolerated by patients with MS; associated with these exercises were recommended flexibility exercises of moderate intensity, as well as strengthening exercises. The aim of this study is to examine the implications of the program of self-regulation in the perception of illness and mental health (psychological well-being domain) in multiple sclerosis patients.