Classification of Energy Momentum Tensors in n≥5n \geq 5 Dimensional Space-times: a Review

Recent developments in string theory suggest that there might exist extra spatial dimensions, which are not small nor compact. The framework of a great number of brane cosmological models is that in which the matter fields are confined on a brane-world embedded in five dimensions (the bulk). Motivated by this we review the main results on the algebraic classification of second order symmetric tensors in 5-dimensional space-times. All possible Segre types for a symmetric two-tensor are found, and a set of canonical forms for each Segre type is obtained. A limiting diagram for the Segre types of these symmetric tensors in 5-D is built. Two theorems which collect together some basic results on the algebraic structure of second order symmetric tensors in 5-D are presented. We also show how one can obtain, by induction, the classification and the canonical forms of a symmetric two-tensor on n-dimensional (n > 5) spaces from its classification in 5-D spaces, present the Segre types in n-D and the corresponding canonical forms. This classification of symmetric two-tensors in any n-D spaces and their canonical forms are important in the context of n-dimensional brane-worlds context and also in the framework of 11-D supergravity and 10-D superstrings.Comment: LaTex2e, 18 pages. To appear in Braz.J.Phys (2004

Description and molecular phylogeny of a new and one known needle nematode of the genus Paralongidorus (Nematoda: Longidoridae) from grapevine in Portugal

A new and a known longidorid nematode, Paralongidorus lusitanicus n. sp. and Paralongidorus plesioepimikis, are described and illustrated from populations extracted from soil associated with grapevine (Vitis vinifera L.) from Escaroupim and Pó (central-Western Portugal), respectively. The new needle nematode P. lusitanicus n. sp. is characterised by a very large body size (8072–12,022 μm), an expanded and rounded lip region, ca 30 μm wide, with a clear constriction followed by a depression posterior to the amphidial aperture, amphidial fovea very large (11.0–19.0 μm), stirrup-shaped, with conspicuous slit-like aperture as shown in scanning electron microscopy studies, a very long and flexible odontostyle (180.0–223.0 μm), guiding ring located at 28.0–41.5 μm from anterior end, vulva anterior to the mid-body (34–41%), a dorsally convex-conoid tail with rounded terminus (29–42 μm long), bearing two or three pairs of caudal pores and males common (ratio 1:1.6 females) with spicules ca 80 μm long. Morphological and morphometric traits for P. plesioepimikis fit well with the original description, and is reported for the first time in Portugal. Integrative diagnosis of both species was completed with molecular data obtained using D2-D3 expansion segments of 28S rDNA, ITS1-rDNA and partial 18S–rDNA. The phylogenetic relationships of these species with other Paralongidorus spp. using these three molecular markers indicated that P. lusitanicus n. sp. clustered together with other Paralongidorus spp. forming a sister clade with P. plesioepimikis, both of them sharing a large body, long odontostyle, an anteriorly located vulva and an expanded and rounded lip region with a clear constriction followed by a depression posterior to the amphidial aperture

Identifying evoked potential response patterns using independent component analysis and unsupervised learning

Independent Component Analysis(ICA) is a pre-processing step widely used in brain studies. One of the most common problems in artifact elimination or brain activity related studies is the ordering and identification of the independent components(ICs). In this work, a novel procedure is proposed which combines ICA decomposition at trial level with an unsupervised learning algorithm (K-means) at participant level in order to enhance the related signal patterns which might represent interesting brain waves. The feasibility of this methodology is evaluated with EEG data acquired with participants performing on the Halstead Category Test. The analysis shows that it is possible to find the Feedback Error Negativity (FRN) Potential at single-trial level and relate its characteristics with the performance of the participant based on their knowledge of the abstract principle underlying the task.info:eu-repo/semantics/publishedVersio

Segurança nos trabalhos de betonagem em estaleiro

Os acidentes de trabalho na construção continuam a ser uma trágica realidade em Portugal, sendo grande parte das fatalidades resultantes de quedas em altura e esmagamento. Os trabalhos de betonagem de elementos estruturais de edifícios continuam a expor os trabalhadores da construção a riscos que podiam ser evitados, ou minorados, e a contribuir para a elevada sinistralidade neste sector de actividade. Numa análise efectuada aos métodos de trabalho e equipamentos de protecção, actualmente utilizados durante as betonagens, foi possível constatar algumas insuficiências. Neste trabalho aborda-se esta problemática e apresentam-se soluções de prevenção para os riscos profissionais, desenvolvidas no âmbito de um projecto de investigação em curso

Gender and politics: A descriptive and comparative analysis of the statutes of Brazilian and Portuguese political parties

This paper presents a descriptive and comparative analysis of the statutes of Brazilian and Portuguese political parties regarding women’s political participation. The main objective was to evaluate if and in what way women are included in the statutory guidelines. By means of the document analysis technique, we analyzed the statutes of political parties represented in the Chamber of Deputies in the case of Brazil and the Assembly of the Republic in the case of Portugal. Our research hypothesis is that although the explanatory potential of party ideology has declined as political parties from different positions on the spectrum have started to adopt discourses in favor of women’s political participation, left-wing parties remain more inclusive in their texts. We could observe that in both countries, leftist parties remain the main encouragers of women’s political participation, at least in their statutory rules.info:eu-repo/semantics/publishedVersio

Implementing gender quotas in Portugal: A success story?

The so-called Portuguese Parity Law adopted in 2006 determined that candidate lists presented for national, European and local elections must include one third minimum representation of each sex. Following its revision in 2019, the minimum percentage required for each sex increased to 40%. The implementation of the Portuguese Parity Law has succeeded in meeting the direct goals of the policy. However, can the same be said for all stages of implementation? Moreover, even when the numbers tell a success story, what practices and resistances do they conceal? And, finally, has the law contributed to gender empowerment that goes beyond the direct scope of the law? This chapter aims to answer these questions by focusing on the national Parliament and on the major Portuguese parties. It draws on the figures for candidates and MPs between 2002 and 2019 as well as on semi-directive interviews with party stakeholders. The main conclusions are the following. First, the implementation of the law takes place smoothly in all four stages of implementation, although parties have usually gone no further than the minimum quota requirements. Parties’ actions and discourses demonstrate a moderate but serious commitment to the law. Second, both explicit and implicit forms of individual resistance, as well as passive institutional resistance take place at the national level for both parties. These resistances are not intended to cause policy failure, but rather to limit policy success. Third, the indirect effects of the law (i.e., gender empowerment in Parliament) are still limited.info:eu-repo/semantics/acceptedVersio

Study of vanadium doped ZnO films prepared by dc reactive magnetron sputtering at different substrate temperatures

ZnO films doped with vanadium (ZnO:V) have been prepared by dc reactive magnetron sputtering technique at different substrate temperatures (RT–500 C). The effects of the substrate temperature on ZnO:V films properties have been studied. XRD measurements show that only ZnO polycrystalline structure has been obtained, no V2O5 or VO2 crystal phase can be observed. It has been found that the film prepared at low substrate temperature has a preferred orientation along the (002) direction. As the substrate temperature is increased, the (002) peak intensity decreases. When the substrate temperature reaches the 500 ºC, the film shows a random orientation. SEM measurements show a clear formation of the nano-grains in the sample surface when the substrate temperature is higher than 400 º C. The optical properties of the films have been studied by measuring the specular transmittance. The refractive index has been calculated by fitting the transmittance spectra using OJL model combined with harmonic oscillator

Symbolic Computation of Variational Symmetries in Optimal Control

We use a computer algebra system to compute, in an efficient way, optimal control variational symmetries up to a gauge term. The symmetries are then used to obtain families of Noether's first integrals, possibly in the presence of nonconservative external forces. As an application, we obtain eight independent first integrals for the sub-Riemannian nilpotent problem (2,3,5,8).Comment: Presented at the 4th Junior European Meeting on "Control and Optimization", Bialystok Technical University, Bialystok, Poland, 11-14 September 2005. Accepted (24-Feb-2006) to Control & Cybernetic