O objecto e o âmbito da justiça social

Nesta comunicação exploro aquele que deve ser o objecto e o âmbito de uma teoria de justiça. Da resposta a estas duas questões depende a possibilidade de definir princípios de justiça que concebam uma sociedade justa. Assim, tenho em consideração as propostas sobre o objecto e o âmbito da justiça presentes nas teorias de Nozick (libertária), de Rawls (igualitária) e de Walzer (comunitária) e avalio topicamente cada uma das posições. Concluo tentando responder à questão: qual deve ser o objecto e o âmbito de uma teoria de justiça

Sharp mixed norm spherical restriction

Let $d\geq 2$ be an integer and let $2d/(d-1) < q \leq \infty$. In this paper we investigate the sharp form of the mixed norm Fourier extension inequality \begin{equation*} \big\|\widehat{f\sigma}\big\|_{L^q_{{\rm rad}}L^2_{{\rm ang}}(\mathbb{R}^d)} \leq {\bf C}_{d,q}\, \|f\|_{L^2(\mathbb{S}^{d-1},{\rm d}\sigma)}, \end{equation*} established by L. Vega in 1988. Letting $\mathcal{A}_d \subset (2d/(d-1), \infty]$ be the set of exponents for which the constant functions on $\mathbb{S}^{d-1}$ are the unique extremizers of this inequality, we show that: (i) $\mathcal{A}_d$ contains the even integers and $\infty$; (ii) $\mathcal{A}_d$ is an open set in the extended topology; (iii) $\mathcal{A}_d$ contains a neighborhood of infinity $(q_0(d), \infty]$ with $q_0(d) \leq \left(\tfrac{1}{2} + o(1)\right) d\log d$. In low dimensions we show that $q_0(2) \leq 6.76\,;\,q_0(3) \leq 5.45 \,;\, q_0(4) \leq 5.53 \,;\, q_0(5) \leq 6.07$. In particular, this breaks for the first time the even exponent barrier in sharp Fourier restriction theory. The crux of the matter in our approach is to establish a hierarchy between certain weighted norms of Bessel functions, a nontrivial question of independent interest within the theory of special functions.Comment: 21 page

Validation studies of the clock drawing test in mild cognitive impairment

Introduction: Mild Cognitive Impairment (MCI) is a transitional entity between normal aging and Alzheimer’s disease. It is assumed that an early identification and intervention in MCI may delay or slow its progression to dementia and several neuropsychological brief-tests have been investigated in this context. The Clock Drawing Test (CDT) is a widely used instrument in this field; however, its application needs further validation in specific clinical populations, mainly in milder forms of cognitive decline and in the distinction between MCI subtypes. Objectives: To validate three scoring systems of the CDT for the detection of cognitive impairment in a cohort of MCI-patients previously classified in amnestic single-domain (aMCI) and amnestic multidomain (mdMCI) subtypes; to test inter-rater reliability and to compare different subtypes of MCI, attempting to define performance profiles according to qualitative analyses of errors. Methods: The study includes two clinical groups: aMCI and mdMCI, each with 90 subjects, recruited at the Neurology Department of the Centro Hospitalar e Universitário de Coimbra. Their performance was compared with a cohort of 90 community-dwelling controls matched according to gender, age and education. All participants were assessed with Mini Mental State Examination, Montreal Cognitive Assessment (MoCA) and CDT. Clock drawings of MCI patients were scored by a neuropsychologist and an inexperienced rater using three scoring systems - Rouleau, Cahn and Babins. Data were analysed with the Statistical Package for the Social Sciences. Results: There was high inter-rater reliability in CDT scoring systems (p<0,001). Significant correlations were found between the cognitive screening instruments and CDT scoring systems as well as a consistent relationship with performance in visuospatial and executive domains of the MoCA. We also observed qualitative differences between both forms of DCL, with higher error rate of “Conceptual deficit” and “Perseveration” in mdMCI, and “Nonspecific spatial error” regarding the aMCI group. There was only sufficient (60%) discriminatory capacity of total scores of the CDT, comparing control and MCI subjects. Conclusions: Our study showed that CDT scoring systems have high inter-rater reliability to screen for MCI and can be applied in large scale studies and primary health care. Although in this context CDT revealed only sufficient discriminatory capacity and should be used with other cognitive screening tests in order to increase the diagnostic accuracy

Computational vision applied to the segmentation and morphometric characterization of the sciatic nerve in microscopic images

Tese de mestrado integrado. Engenharia Informática e Computação. Faculdade de Engenharia. Universidade do Porto. 201

evoRF: An Evolutionary Approach to Random Forests

Machine Learning is a field in which significant steps forward have been taken in the last years, resulting in a wide variety of available algorithms, for many different problems. Nonetheless, most of these algorithms focus on the training of static models, in the sense that the model stops evolving after the training phase. This is increasingly becoming a limitation, especially in an era in which datasets are increasingly larger and may even arrive as sequential streams of data. Frequently retraining a model, in these scenarios, is not realistic. In this paper we propose evoRF: a combination of a Random Forest with an evolutionary approach. Its key innovative aspect is the evolution of the weights of the Random Forest over time, as new data arrives, thus making the forest’s voting scheme adapt to the new data. Older trees can also be replaced by newly trained ones, according to their accuracy, ensuring that the ensemble remains up to date without requiring a whole retraining.This work has been supported by FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2019

A general template to configure multi-criteria problems in Ubiquitous GDSS

The study of multi-criteria problems adapted to the context of Ubiquitous Group Decision Support Systems (UbiGDSS) is covered in the literature through very different perspectives and interests. There are scientific studies related to the multi-criteria problems that lie across argumentation-based negotiation, multi-agent systems, dialogues, etc. However, to perform most of these studies, a high amount of information is required. The usage of so much data or information that is difficult to collect or configure can bring good results in theoretical scenarios but can be impossible to use in the real world. In order to overcome these issues, we present in this paper a general template to configure multi-criteria problems adapted for the contexts of UbiGDSS that intends to be easy and fast to configure, appellative, intuitive, permits to collect a lot of data and helps the decision-maker transmitting his beliefs and opinions to the system. Our proposal includes three sections: Problem Data, Personal Configuration and Problem Configuration. We have developed a prototype with our template with the purpose to simulate the configuration of a multi-criteria problem. We invited real decision-makers to use our prototype in a simulated scenario and asked to them to fulfil a survey in the end in order to study our hypotheses. Our general template achieved good results and proved to be very perceptible and fast to configure.This work is part-funded by ERDF - European Regional Development Fund through the COMPETE Programme (operational programme for competitiveness) within project FCOMP-01-0124-FEDER-028980 (PTDC/EEISII/1386/2012) and by National Funds through the FCT - Fundação para a Ciência e a Tecnologia (Portuguese Foundation for Science and Technology) with the João Carneiro PhD grant with the reference SFRH/BD/89697/2012.info:eu-repo/semantics/publishedVersio

Processamento e caraterização de uma peça automóvel processado com tecnologia Mucell Vs Injeção convencional

Dissertação de mestrado integrado em Engenharia de PolímerosA indústria automóvel é marcada pela elevada competitividade e exigência na qualidade dos produtos. Estas empresas procuram métodos que lhes permitam reduzir custos, melhorar a qualidade dos produtos e a satisfação do cliente. As peças processadas por injeção com recurso a tecnologia MuCell possuem aplicações importantes para as diferentes áreas industriais. O uso da tecnologia MuCell permite utilizar diferentes materiais plásticos na produção de peças e apresenta várias vantagens como: redução do peso da peça e diminuição do tempo de ciclo, o que resulta na economia de custos e obtenção de peças mais complexas com design inovador. Este estudo decorreu em ambiente industrial na empresa MicroPlásticos. No presente estudo foram utilizados dois materiais, o Polipropileno (PP) e o poli (tereftalato de butileno) (PBT) com o objetivo de comparar a nível físico e mecânico peças processadas com injeção convencional e peças processadas com á recurso á tecnologia MuCell injetando diferente percentagens de Azoto. Ao longo do estudo verificou-se a influência da injeção de gás (Azoto), quer no tempo de ciclo de injeção, na contração e peso da peça, na resistência mecânica, bem como na observação do gás no núcleo das peças. Observou-se uma diminuição natural do peso das peças, bem como nas das propriedades mecânicas que é influenciada pelo aumento das diferentes percentagens de gás.The automotive industry is marked by high competitiveness and demand in the product quality. These companies search for methods that allow the reduction of costs, product quality improvement and client satisfaction. The parts processed by injection using MuCell technology have important applications for different industry areas. MuCell tecnology allows the use of different plastic materials in manufacture and has several advantages such as weight reduction and decreased cycle time, this results in cost savings and the ability of acquire more complex parts with innovative design. This study used Polypropylene (PP) and Polybutylene Terephthalate (PBT) to compare, at a physical and mechanical level, a part processed by injection using MuCell technology and conventional injection (without MuCell). Using MuCell technology, the material is processed with different percentages to assess the influence of the gas injection. Throughout the study it was evaluated the influence of gas injection (Nitrogen) whether on injection cycle time, mechanical resistance, shrinkage, and weight of the parts, and it was also observed the gas in the core of the parts. There was a natural decrease in the parts weight as well as in the mechanical properties due to the addition of different percentages of gas