Reuse of ancient megalithics monuments during Metal Ages: the dolmen of Serrinha (Monforte, Portugal).

The set of funerary megalithic monuments in the Alentejo region (Portugal) presents a great variety in its architectures, but also in their uses and reuses. Although often undocumented (in the case of ancient excavations), the collections in the Museums prove their use between the Neolithic Age and at least the Iron Age. The Dolmen of Serrinha (Monforte) recently excavated by the signatories, is a good example of the reuse of necropolis spaces during Metal Ages

Stability of quaternionic systems: a determinantal approach

In this paper we propose a definition of determinant for quaternionic polynomial matrices. This definition is later used in the study of stability of linear quaternionic systems within the behavioral setting

On the determinant of quaternionic polynomial matrices and its application to system stability

In this paper, we propose a definition of determinant for quaternionic, polynomial matrices inspired by the well-known Dieudonne determinant for the constant case. This notion allows to characterize the stability of linear dynamical systems with quaternionic coefficients, yielding results which generalize the ones obtained for the real and complex cases

Multistage Stochastic Portfolio Optimisation in Deregulated Electricity Markets Using Linear Decision Rules

The deregulation of electricity markets increases the financial risk faced by retailers who procure electric energy on the spot market to meet their customers’ electricity demand. To hedge against this exposure, retailers often hold a portfolio of electricity derivative contracts. In this paper, we propose a multistage stochastic mean-variance optimisation model for the management of such a portfolio. To reduce computational complexity, we perform two approximations: stage-aggregation and linear decision rules (LDR). The LDR approach consists of restricting the set of decision rules to those affine in the history of the random parameters. When applied to mean-variance optimisation models, it leads to convex quadratic programs. Since their size grows typically only polynomially with the number of periods, they can be efficiently solved. Our numerical experiments illustrate the value of adaptivity inherent in the LDR method and its potential for enabling scalability to problems with many periods.OR in energy, electricity portfolio management, stochastic programming, risk management, linear decision rules

Global reachability of 2D structured systems

In this paper the new concept of 2D structured system is defined and a characterization of global reachability is obtained. This extends a well known result for 1D structured systems, according to which (A ,B ) is (generically) reachable if and only if the matrix [A B] is full generically row rank and irreducible

Experiências Dissociativas e Traumáticas em Mulheres Internadas com Perturbações de Humor

Esta investigação pretendeu averiguar se mulheres internadas com Perturbações de Humor dissociam e se o trauma se relaciona com os sintomas dissociativos. Seleccionámos consecutivamente 41 mulheres em regime de internamento, com idades compreendidas entre os 22 e 77 anos. A amostra foi dividida em subamostras: doentes com Perturbação Depressiva (n = 25), Perturbação Bipolar (n = 6), e Outras Perturbações de Humor (n = 10). Para a confirmação dos diagnósticos psicopatológicos, recorremos a uma entrevista estruturada, a Mini International Neuropsychiatric Interview (MINI). Na recolha dos dados usámos a Dissociative Experiences Scale (DES) e o Traumatic Experiencies Checklist (TEC) para avaliar as experiências dissociativas e traumáticas. Para controlar os sintomas depressivos e psicopatológicos aplicámos o Beck Depression Inventory (BDI) e o Brief Symptom Inventory (BSI) respectivamente. Os doentes com perturbações de humor, no seu todo, pontuam mais alto no factor distractibilidade do DES e tiveram experiências traumáticas particularmente elevadas dos 0 aos 6 anos e na família de origem. Não se verificaram diferenças significativas entre as subamostras, nem na dissociação, nem no trauma. Não observámos relação significativa entre as experiências dissociativas e traumáticas. Todavia, estas variáveis associaram-se com o BDI e BSI. Por fim, verificámos que o sintoma de hostilidade prediz a dissociação. O nosso estudo é o primeiro a investigar as experiências traumáticas em doentes com Perturbações de Humor e a obter estes resultados. A nossa amostra não foi equilibrada nos três tipos de patologia, pelo que os nossos resultados deveriam ser confirmados num estudo futuro

China’s images in the State of the Union Address, 1973-2020

This paper discusses how China was represented in the State of The Union Address between 1973 and 2020. The hypothesis is that China’s image has undergone qualitative changes and that shifting the party in the White House is not a sufficient condition to transform this representation. It is employed the content analysis to map the frequency of the word ‘China’ and to analyze the discursive context of its apparition. The mentions are evaluated according to three variables: axiology (positive, negative, or mixed), discursive focus (direct or indirect), and frequency of mentions. Four discursive paradigms, or periods in which the image was qualitatively stable, are identified and discussed. The analysis showed that external shocks have an important impact on changing China’s image and that these representations usually signalize actual priorities of US foreign policy

A remark on conditioned invariance in the behavioral approach

In this paper a definition for the property of behavioral invariance is proposed with the purpose of generalizing the state space geometric approach to the behavioral setting. Based on this notion together with the well-known notion of behavioral observer, a definition of conditioned invariance is also presented. The results obtained for the characterization of the defined properties put into evidence some problems that, in our opinion, should deserve attention. This could serve as a starting point for a discussion on the foundations of an analogue of the geometric theory within the behavioral setting