On Graph Refutation for Relational Inclusions

We introduce a graphical refutation calculus for relational inclusions: it reduces establishing a relational inclusion to establishing that a graph constructed from it has empty extension. This sound and complete calculus is conceptually simpler and easier to use than the usual ones.Comment: In Proceedings LSFA 2011, arXiv:1203.542

New Phytophthora populations: A shift from indirect to direct sporangial germination?

Phytophthora infestans, the causal agent of potato- and tomato late blight, remains a serious threat for (commercial) potato and tomato production. In North Western Europe, frequent fungicide applications, mostly aimed to prevent infection, form the back bone of potato late blight control. Modern protectants such as Shirlan (a.i. fluazinam) are highly effective against (germinating) P. infestans sporangia and zoospores. Zoospores in particular are so sensitive to low concentrations that the many applications over the past two decades may well have exerted sufficient selection to pressure against the formation of zoospores. Thus, over the years the balance between direct and indirect germination may have shifted towards direct germination. This hypothesis was investigated at Bayer Crop Science and Plant Research Internationa

On Graphical Calculi for Modal Logics

We present a graphical approach to classical and intuitionistic modal logics, which provides uniform formalisms for expressing, analysing and comparing their semantics. This approach uses the flexibility of graphical calculi to express directly and intuitively the semantics for modal logics. We illustrate the benefits of these ideas by applying them to some familiar cases of classical and intuitionistic multi-modal logics.Cálculos Gráficos para lógicas modais Apresentamos uma abordagem gráfica para as lógicas modais clássica e intuicionista, capaz de fornecer formalismos uniformes para expressar, analisar e comparar suas respectivas semânticas. Tal abordagem utiliza a flexibilidade dos cálculos gráficos para expressar, direta e intuitivamente, a semântica das lógicas modais. Ilustramos os benefícios dessas ideias aplicando-as a alguns casos conhecidos de lógicas multimodais clássica e intuicionista.---Artigo em inglês

Adolescent's physical activity : perspectives for active lifestyles of a school population in Oeiras

FCT (Fundação para a Ciência e a Tecnologia), IDP (Instituto do Desporto de Portugal), AIESEP World Congres

Precarious organizing and beyond: the case of arts and construction industry

Ongoing reconfigurations of work under contemporary global capitalism increasingly defy the centrality of the workplace for workers’ organizing. Some sectors, though, have always been challenged by the lack of a stable workplace and by the temporary nature of work relations. That is the case of the arts and construction industry which provide longstanding examples of precarious and mobile work and have been related to precarious organizing. Despite representing two distinct sectors of the workforce, they present a set of similarities that challenge the possibilities of workers’ organisation and mobilisation: the temporary, project-based nature of work; the precarious employment arrangements, often informal; the mobile nature of work activities, not linked to a fixed workplace. Based on the Portuguese context, this paper provides a comparative analysis of both sectors, arguing on their analytical significance to explore new forms of workers’ solidarity and broader terrains of struggle.N/

Desenvolvimento inicial do arroz com a antecipação da adubação de nitrogênio e seu efeito na produtividade do arroz no município de Paragominas, PA.

Analisou-se a resposta do arroz de terras altas cultivado em Latossolo Amarelo distrofico na região Nordeste Paraense, ao parcelamento e épocas de aplicação de fertilizante nitrogenado. Observou-se também as formas que permitam adaptar o sistema de produção do arroz de terras altas ao plantio direto de forma a permitir que faca parte de sistemas agrícolas em rotação com soja, adequando ao manejo de adubação, a relação de formas de N no solo, aos tipos e época de manejo das coberturas de solo e a qualidade de semeadura

Free mobility, locked rights: the posting of construction workers from Portugal

Mobility has become a cornerstone of the contemporary social world. In the European Union, the removal of barriers aimed at promoting the free movement of the labour force is a major goal of the integration process. This article investigates the political economy of posting, analysing the working and living conditions of Portuguese construction workers posted to other EU Member States. It highlights a set of abusive and exploitative practices involved in posting and the role those practices play in the (de)regulation of labour within the construction sector. In spite of the access to a pan-European labour market and the general principle of equal treatment, posted workers have restricted social rights in the host country. The study presented is based on research developed within the ‘EU Post Lab’ project, aimed at promoting activities of cooperation and awareness raising in the field of posting. The methodology adopted includes document analysis and interviews.info:eu-repo/semantics/acceptedVersio