On the minimal ranks of matrix pencils and the existence of a best approximate block-term tensor decomposition

Under the action of the general linear group with tensor structure, the ranks of matrices $A$ and $B$ forming an $m \times n$ pencil $A + \lambda B$ can change, but in a restricted manner. Specifically, with every pencil one can associate a pair of minimal ranks, which is unique up to a permutation. This notion can be defined for matrix pencils and, more generally, also for matrix polynomials of arbitrary degree. In this paper, we provide a formal definition of the minimal ranks, discuss its properties and the natural hierarchy it induces in a pencil space. Then, we show how the minimal ranks of a pencil can be determined from its Kronecker canonical form. For illustration, we classify the orbits according to their minimal ranks (under the action of the general linear group) in the case of real pencils with $m, n \le 4$. Subsequently, we show that real regular $2k \times 2k$ pencils having only complex-valued eigenvalues, which form an open positive-volume set, do not admit a best approximation (in the norm topology) on the set of real pencils whose minimal ranks are bounded by $2k-1$. Our results can be interpreted from a tensor viewpoint, where the minimal ranks of a degree-$(d-1)$ matrix polynomial characterize the minimal ranks of matrices constituting a block-term decomposition of an $m \times n \times d$ tensor into a sum of matrix-vector tensor products.Comment: This work was supported by the European Research Council under the European Programme FP7/2007-2013, Grant AdG-2013-320594 "DECODA.

Psicolinguística Aplicada: Uma Ciência na Encruzilhada da Cognição e da Linguagem

Abstract: Applied Psycholinguistics is a science that engages many others: experimental psychology, cognitive and neurocognitive sciences, linguistics, psychology of language and literacy, and educational and remediation sciences. The present paper’s objective is to show Science is itself a changing combination of ever-changing sciences without close boundaries, which implies the necessity of crossing domains in both research and learning. After a reminder of several topics of relevance to applied psycholinguistics, which concern mental processing, how cognition relates to the brain and to language, and how cognition and language engendered literacy, I argue that research in the corresponding sciences needs to be opened to other dimensions, such as society, culture, and politics. Finally, I evoke the history of the ideas regarding the isolationism of individualized sciences vs. their unification, taking, as examples of the latter, the early Marxism, and the International Movement for the Unity of Science from the fourth decade of the 20th century.   Keywords: Applied Psycholinguistics; literacy as product of cognition and language; concept of Science; history of scientific ideas; permeability of science to culture and politics.Resumo: A Psicolinguística Aplicada é uma ciência que envolve muitas outras: psicologia experimental, ciências cognitivas e neurocognitivas, linguística, psicologia da linguagem e da literacia, e ciências da educação e da remediação. O objetivo do presente artigo é mostrar que a Ciência é, mais exatamente, uma combinação em constante mudança de ciências sem fronteiras fechadas, o que implica a necessidade de cruzar domínios tanto na pesquisa quanto na aprendizagem. Depois de relembrar vários tópicos de relevância para a psicolinguística aplicada, que dizem respeito ao processamento mental, a como a cognição se relaciona com o cérebro e a linguagem e a como a cognição e a linguagem engendram a literacia, defendo que a pesquisa nas ciências correspondentes precisa ser aberta a outras dimensões tais como a sociedade, a cultura e a política. Por fim, evoco a história das ideias no que respeita ao isolacionismo das ciências individualizadas versus a sua unificação, tomando como exemplos desta última o marxismo inicial e o Movimento Internacional pela Unidade da Ciência na quarta década do século XX.   Palavras-chave: Psicolinguística Aplicada; literacia como produto da cognição e da linguagem; conceito de Ciência; história das ideias científicas; permeabilidade da ciência à cultura e à política

Escola e mudança social: recém-licenciados na área de informática em instituições de ensino superior localizadas na área metropolitana do Porto

This article is based on a Ph.D. in sociology research conducted at FLUP. It seeks to capture the continuities and transformations between levels of socialization and structure of habitus in a specific group of the Portuguese population: new graduates in computing in higher education institutions located in the metropolitan area of Porto. The data that are presented here refer to intergenerational courses in terms of class, putting the school in the heart of the problem of change and social reproduction. The aim of the research that underpins this article focused on the uptake of practices and representations of this particular group with the aim of concluding on the dynamics that characterize Portugal, a country in transition to a network society

On a radiative origin of the Standard Model from Trinification

In this work, we present a trinification-based grand unified theory incorporating a global $\mathrm{SU}(3)$ family symmetry that after a spontaneous breaking leads to a left-right symmetric model. Already at the classical level, this model can accommodate the matter content and the quark Cabbibo mixing in the Standard Model (SM) with only one Yukawa coupling at the unification scale. Considering the minimal low-energy scenario with the least amount of light states, we show that the resulting effective theory enables dynamical breaking of its gauge group down to that of the SM by means of radiative corrections accounted for by the renormalisation group evolution at one loop. This result paves the way for a consistent explanation of the SM breaking scale and fermion mass hierarchies.Comment: 39 pages, 6 figures. Added a discussion (Sect. 7.2) on 1-loop contributions to the masses of light scalars. Published versio

Mundicenter : the struggle to survive in a saturated market

In 2013, Mundicenter, one of the subsidiaries of the Portuguese Group Alves Ribeiro received a wake-up call when the results of 2012 came up. This company operated in the malls development industry, a complex and highly saturated market facing a period of great macro- economic and internal market changes, jeopardizing its 30 years of existence. This company ended up in a position where a revolutionary decision was needed to survive. Managers had to decide between keep doing damage control and follow the holding’s preferences or proceed to a strategy restructuring involving a high investment in a critical period, going against the Group conservative culture. These times were very difficult for the company’s managers that had two fronts to beat, first the internal culture and second the market conditions.Em 2013, na Mundicenter, uma das subsidiárias da empresa portuguesa Grupo Alves Ribeiro soou o alarme quando os resultados de 2012 saíram. Esta empresa estava inserida na indústria de desenvolvimento de centros comerciais, um mercado complexo e altamente saturado que atravessava um período de grande turbulência pautado por mudanças macroeconómicas e no mercado interno colocando em risco os seus 30 anos de existência. Esta empresa acabou vendo-se numa posição em que foi obrigada a tomar uma decisão de elevado risco para sobreviver. Os administradores tiveram de decidir entre continuar a fazer controlo de danos e seguir as políticas da empresa-mãe ou proceder a uma reestruturação estratégica envolvendo um elevado investimento numa época crítica, indo contra as práticas conservadoras do Grupo. Aqueles tempos foram caracterizados pelas dificuldades passadas pelos gestores da empresa que tinha de lutar em duas frentes diferentes, pela primeira vez a cultura interna e segundo as condições de mercado

Assessment and reporting of adverse drug reactions to iopromide: a study of risk perception and pharmacovigilance

Tesis por compendio de publicaciones[EN]To achieve the thesis goals, two original articles were performed, the first to evaluate patients’ awareness of ADR risks and the Portuguese Pharmacovigilance System and the second to provide a retrospective analysis of ADR to iopromide in a Portuguese private unit of radiology. In addition, to reinforce the background of the thesis, two review articles were incorporated: a narrative review of the safety assessment of iopromide focusing on adverse events and a scoping review of all-round approaches to increase adverse drug reaction reporting. [ES]Para lograr los objetivos de la tesis, organizada en compendio de artículos, se realizaron dos artículos originales, uno para evaluar el conocimiento de los pacientes sobre los riesgos de RAM y el Sistema de Farmacovigilancia de Portugal y otro para proporcionar un análisis retrospectivo de RAM a iopromida en una unidad privada de radiología portuguesa. Además, para reforzar los antecedentes de la tesis, se agregaron dos artículos de revisión, uno que utiliza una revisión narrativa de la evaluación de la seguridad de la iopromida que se centra en los eventos adversos y una revisión de alcance de enfoques integrales para aumentar la notificación de reacciones adversas a medicamentos

A Theoretical Contribution To Improve The Formation In The Historical Lisbon School Of Architecture - The Forgotten Dimension of the Technological Perspective

This article approaches the problem of the absence of the technology in the didactics of the Architecture´s Design, in the course of School of Architecture of Lisbon, as the subtitle of the article suggests - the forgotten dimension of the technological perspective.Despite of the course contemplates a relevant technological component, however, does not reflect, much less exponent the creative act of the Project. This is first of all a result of the organization, didactics and contents of the Project classes, and not so much, a lack of knowledge provided to the student in the technological disciplines, which are present in quantity in the curricular structure. The situation, analyzed in this article, is a consequence of a blocking of the Project classes to the technology ones, which do not promote, nor allow, the necessary transdisciplinary articulation and integration between the act of designing and the application of technological knowledge, which is fundamental and intrinsic to the act of thinking and conceiving Architecture.The CAD / CAE / CAM digital tools have not only highlighted the fragility of this didactic process in the didactic context of the current teaching, but, in view of the potential of its operative process, impose the future reformulation of the Project's cognitive practice, integrating the component technology in the Design Methodology of the architect's teaching and praxisN/

Navigating "hybrid threats" inside the UNSC: The Russian use of the legal and diplomacy domains towards the post-Arab Spring war in Syria

Hybrid threats became a growing object of study in the field of International Relations, due to its multifaceted nature. However, the use of its legal and diplomacy domains within multilateral organizations to advance political objectives is still an understudied topic. A potential “normalization” of the phenomenon impacts the legitimacy of those organizations, and the rule of law in democratic societies. Countering those threats requires comprehensive strategies for mitigation and coordinated, multilevel collaboration and information sharing. This study contributes to understanding the implications that the use of hybrid threats poses to the legitimacy of the international legal system, through examining its existence and main motivations inside the UN. Based on Giannopoulos, et al., ed. (2021) framework, it will be examined if and why Russia, in its role as a UNSC permanent member, is using the legal and diplomacy domains of Hybrid Threats inside the UNSC, towards the war in Syria (2011-current). It will be tested the hypothesis of a potential causal effect between Russia´s domestic and foreign policy, built on its post-soviet identity project, with the goal of enhancing its own political objectives. The research suggests that Russia is using international law and diplomacy in an abusive way to promote its political objectives, that may be framed as hybrid threat. It is argued that Russia is taking opportunity of its role in the UNSC to promote counter-hegemonic moves, motivated by geostrategic objectives, but also by its identity project, intersecting security, and power relations.As ameaças híbridas tornaram-se um objeto de estudo crescente no campo das relações internacionais, devido à sua natureza multifacetada. No entanto, a utilização dos seus domínios jurídico e diplomático no âmbito de organizações multilaterais para promoção de objetivos políticos é ainda um tema pouco estudado. Uma potencial “normalização” deste fenómeno impacta a legitimidade destas organizações e do Estado de Direito em sociedades democráticas. Combater essas ameaças exige estratégias abrangentes de mitigação, colaboração coordenada e partilha de informações. Este estudo contribui para a compreensão das implicações que o uso de ameaças híbridas representa para a legitimidade do sistema jurídico internacional, através do exame da sua existência e principais motivações no contexto da ONU. Com base no modelo de análise de Giannopoulos et al., ed. (2021), será examinado se e por que razão a Rússia, enquanto membro permanente do CSNU, utiliza os domínios jurídicos e diplomáticos das ameaças híbridas dentro desse órgão, no contexto da guerra na Síria (2011 - atual). Será testada a hipótese de um efeito causal entre a política interna e externa da Rússia, construída a partir do seu projeto de identidade pós-soviético, com o objetivo alavancar objetivos políticos. A investigação sugere que a Rússia utiliza o direito internacional e a diplomacia de forma abusiva para promover objetivos próprios, podendo essa atuação ser enquadrada como ameaça híbrida. Argumenta-se que a Rússia tira proveito do seu papel no CSNU para promover movimentos contra-hegemónicos, motivada por objetivos geoestratégicos, mas também pelo seu projeto de identidade, intersetando segurança e relações de poder

Drivers of corporate bankruptcy and default : study concerning Portuguese Companies

My purpose with this dissertation is to investigate the relevance of financial and economic variables as predictors of corporate bankruptcy (default) in Portugal. Understanding the underlying issues behind corporate distress and failure is crucial for several areas particularly: granting (or not) a bank loan, managing credit risk and pricing debt. The present financial and economic crisis stimulated a growing interest on matters related to corporate default, ratings and scoring models. In this dissertation, I apply, to a sample of medium-large Portuguese companies, updated statistical models for identifying the fundamental variables that lead to bankruptcy (and default), and if they are mainly idiosyncratic and / or systematic, affecting simultaneously all firms. I also fit hazard model for studying hazard rates and survival-time, trying to disclose which variables can shield firms from a hazard event, in this case, bankruptcy. The sample was provided by COFACE, a known credit scoring company and included full annual financial statements, from years 2006 to 2011, adding additional requested information, namely, about bankruptcies and legal actions against firms due to payment default. My findings support the conclusion that some financial and economic variables do influence bankruptcy and default probability together with survival-time, which is perfectly anticipated by corporate finance analysis theory and practice. Nevertheless, I reached some conclusions that contradict others from similar studies