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Browsing by Issue Date, starting with "2012-06"

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  • Representação proporcional - métodos dos divisores
    Publication . Fernandes, Susana
    O atual programa da disciplina Matemática Aplicada a Ciências Sociais (MACS) do ensino secundário inclui, sob o tema da teoria da partilha equilibrada, a representação proporcional, que é uma aplicação da teoria da divisão proporcional no caso discreto. Neste âmbito são abordados alguns métodos de origem norte-americana (Hamilton, Jefferson, Adams, Webster, Huntington-Hill), pelo seu interesse histórico, e os dois métodos de origem europeia mais usados atualmente (D’Hondt e Sainte-Laguë). Neste texto salientaremos que todos estes métodos, exceto o de Hamilton, são métodos de divisores e que os dois métodos europeus abordados (D’Hondt e Sainte-Laguë) são na realidade equivalentes a dois dos métodos americanos (Jefferson e Webster), diferindo apenas na forma de cálculo.
    2012-06Journal article Open Access Show more
  • Organisational knowledge management: three case studies in the hospitality industry
    Publication . Sequeira, Bernardete; Serrano, António; Marques, João Filipe
    Under organisational theories, knowledge management is the organisational capacity to develop, innovate and enhance competitiveness. From this perspective, knowledge management is a management context in which knowledge is used. The main issue is the creation of an environment in which the development, acquisition and dissemination of new knowledge can be fostered and nurtured using organisational tools explicitly designed for that purpose. From the perspective of organisations, knowledge resides in documents, routines, procedures, practices and norms. However, above all, knowledge is reflected in the organisational development of new products and services, in taking decisions regarding customers and in the formulation of strategies. Such knowledge is the result of the dissemination of knowledge by individual organisational structures. Hospitality is an activity-based service sector in which information and knowledge are fundamental in order to develop realistic strategies and business plans. This paper thus presents an analytical model and several preliminary results of an investigation called "Organisational Knowledge Management in Tourism Organisations". This study investigates how tourism organisations in the Algarve region of Portugal manage knowledge by observing how they create, retain, share and use it. This empirical research is based on three case studies of hotels that use documental research, interviews and questionnaires as well as the analytic model introduced herein. The latter identifies the different stages of knowledge management (acquisition / knowledge creation and retention / storage and transfer / sharing and use) and the management practices that facilitate it (strategic management, organisational culture, structure and work processes, human resources policies, information systems and communication, measuring results and relationships with the environment outside the organisation). As far as is possible, we have taken into account the multifaceted characteristics of knowledge management and its practical significance. The two major axes of the model do not exist in isolation. Rather, they complement each other and are essential for a comprehensive approach to knowledge management.
    2012-06Conference object Unknown Show more
  • Behaviour of fish by-catch in the mouth of a crustacean trawl
    Publication . Queirolo, D.; Gaete, E.; Montenegro, I.; Soriguer, M. C.; Erzini, Karim
    The behaviour of fish by-catch was recorded and characterized by in situ observations in the mouth of a crustacean trawl using an underwater camera system with artificial light, at depths between 106 and 461 m, along the central coast of Chile. The groups or species studied were rattails (family Macrouridae), Chilean hake Merluccius gayi gayi, sharks (orders Carcharhiniformes and Squaliformes), skates (family Rajidae), flatfishes (genus Hippoglossina) and small benthopelagic and demersal fishes (orders Osmeriformes, Stomiiformes, Gadiformes, Ophidiiformes and Perciformes). The fish behaviour was categorized in terms of (1) position in the water column, (2) initial orientation with respect to the trawl, (3) locomotion and (4) swimming speed with respect to the trawl. Rattails, sharks, skates and flatfishes were passive in response to the trawl and showed similar behavioural patterns, with most fishes observed sitting or touching the bottom with no swimming or other activity. Merluccius gayi gayi was the most active species, displaying a wide combination of behavioural responses when the trawl approached. This species showed several behavioural patterns, mainly characterized by swimming forward at variable speed. A fraction of small bentho-pelagic and demersal fishes also showed an active behaviour but always at lower speed than the trawl. The species-specific differences in behaviour in the mouth of the trawl suggest that improvements at the level of the footrope can be made to reduce by-catch, especially of passive species.
    2012-06Journal article Restricted Show more
  • Water-Borne Cues of a Non-Indigenous Seaweed Mediate Grazer-Deterrent Responses in Native Seaweeds, but Not Vice Versa
    Publication . Yun, Hee Young; Engelen, Aschwin H.; Santos, Rui O.; Molis, Markus
    Plants optimise their resistance to herbivores by regulating deterrent responses on demand. Induction of anti-herbivory defences can occur directly in grazed plants or from emission of risk cues to the environment, which modifies interactions of adjacent plants with, for instance, their consumers. This study confirmed the induction of anti-herbivory responses by water-borne risk cues between adjoining con-specific seaweeds and firstly examined whether plant-plant signalling also exists among adjacent hetero-specific seaweeds. Furthermore, differential abilities and geographic variation in plant-plant signalling by a non-indigenous seaweed as well as native seaweeds were assessed. Twelve-day induction experiments using the non-indigenous seaweed Sargassum muticum were conducted in the laboratory in Portugal and Germany with one local con-familiar (Portugal: Cystoseira humilis, Germany: Halidrys siliquosa) and hetero-familiar native species (Portugal: Fucus spiralis, Germany: F. vesiculosus). All seaweeds were grazed by a local isopod species (Portugal: Stenosoma nadejda, Germany: Idotea baltica) and were positioned upstream of con-and hetero-specific seaweeds. Grazing-induced modification in seaweed traits were tested in three-day feeding assays between cue-exposed and cue-free (= control) pieces of both fresh and reconstituted seaweeds. Both Fucus species reduced their palatability when positioned downstream of isopod-grazed con-specifics. Yet, the palatability of non-indigenous S. muticum remained constant in the presence of upstream grazed con-specifics and native hetero-specifics. In contrast, both con-familiar (but neither hetero-familiar) native species reduced palatability when located downstream of grazed S. muticum. Similar patterns of grazer-deterrent responses to water-borne cues were observed on both European shores, and were almost identical between assays using fresh and reconstituted seaweeds. Hence, seaweeds may use plant-plant signalling to optimise chemical resistance to consumers, though this ability appeared to be species-specific. Furthermore, this study suggests that native species may benefit more than a non-indigenous species from water-borne cue mediated reduction in consumption as only natives responded to signals emitted by hetero-specifics.
    2012-06Journal article Open Access Show more
  • TriPer, an optical probe tuned to the endoplasmic reticulum tracks changes in luminal H2O2
    Publication . Melo, Eduardo; Rafael dos Reis Lopes, Carlos; Gollwitzer, Peter; Lortz, Stephan; Lenzen, Sigurd; Mehmeti, Ilir; Kaminski, Clemens F.; Ron, David; Avezov, Edward
    Background: The fate of hydrogen peroxide (H2O2) in the endoplasmic reticulum (ER) has been inferred indirectly from the activity of ER-localized thiol oxidases and peroxiredoxins, in vitro, and the consequences of their genetic manipulation, in vivo. Over the years hints have suggested that glutathione, puzzlingly abundant in the ER lumen, might have a role in reducing the heavy burden of H2O2 produced by the luminal enzymatic machinery for disulfide bond formation. However, limitations in existing organelle-targeted H2O2 probes have rendered them inert in the thiol-oxidizing ER, precluding experimental follow-up of glutathione's role in ER H2O2 metabolism. Results: Here we report on the development of TriPer, a vital optical probe sensitive to changes in the concentration of H2O2 in the thiol-oxidizing environment of the ER. Consistent with the hypothesized contribution of oxidative protein folding to H2O2 production, ER-localized TriPer detected an increase in the luminal H2O2 signal upon induction of pro-insulin (a disulfide-bonded protein of pancreatic beta-cells), which was attenuated by the ectopic expression of catalase in the ER lumen. Interfering with glutathione production in the cytosol by buthionine sulfoximine (BSO) or enhancing its localized destruction by expression of the glutathione-degrading enzyme ChaC1 in the lumen of the ER further enhanced the luminal H2O2 signal and eroded beta-cell viability. Conclusions: A tri-cysteine system with a single peroxidatic thiol enables H2O2 detection in oxidizing milieux such as that of the ER. Tracking ER H2O2 in live pancreatic beta-cells points to a role for glutathione in H2O2 turnover.
    2012-06Journal article Open Access Show more
  • Cortical multiscale line-edge disparity model
    Publication . Rodrigues, J. M. F.; Martins, Jaime; Lam, Roberto; du Buf, J. M. H.
    Most biological approaches to disparity extraction rely on the disparity energy model (DEM). In this paper we present an alternative approach which can complement the DEM model. This approach is based on the multiscale coding of lines and edges, because surface structures are composed of lines and edges and contours of objects often cause edges against their background. We show that the line/edge approach can be used to create a 3D wireframe representation of a scene and the objects therein. It can also significantly improve the accuracy of the DEM model, such that our biological models can compete with some state-of-the-art algorithms from computer vision.
    2012-06Book part Open Access Show more
  • Um olhar sobre uma competição matemática na Web: os SUBs
    Publication . Carreira, Susana; Amado, Nélia; Ferreira, Rosa; Silva, Jaime Carvalho e; Rodriguez, Juan; Jacinto, Hélia; Amaral, Nuno; Nobre, Sandra; Martins, Isa; Reis, Sílvia; Mestre, Rita Brito
    Problem@Web é um projeto de investigação na área da Educação Matemática, financiado pela Fundação para a Ciência e a Tecnologia, instituto público tutelado pelo Ministério da Educação e Ciência que promove e financia projetos em todos os domínios da ciência e da tecnologia. Este projeto tem como objetivo geral estudar a resolução de problemas de matemática num contexto exterior à sala de aula – as competições matemáticas baseadas na Internet, nas quais se incluem os campeonatos de matemática SUB12 e SUB14, promovidos pelo Departamento de Matemática da Faculdade de Ciências e Tecnologia da Universidade do Algarve. O SUB12 e o SUB14 são campeonatos de resolução de problemas dirigidos a todos os alunos dos 5º, 6º, 7º e 8º anos de escolaridade das regiões do Algarve e Alentejo e decorrem online, culminando com uma final presencial.
    2012-06Book Open Access Show more
  • Inovação urbana nos serviços de base local prestados pelas organizações de economia social – a cidade de lisboa em análise
    Publication . Sousa, Vanessa Duarte de
    Face às tensões e às oportunidades que emergem da cidade, interessa perceber a forma como as organizações procuram dar uma resposta direta aos problemas e às necessidades dos cidadãos. Incidindo sobre as organizações cujo perfil se enquadra nos critérios europeus de definição da economia social (Ávila e Campos, 2007), o enfoque é centrado sobre aquelas que desenvolvem serviços de base local. Entendem-se por estes serviços aqueles que suprem necessidades sociais dos indivíduos a partir de uma perspetiva assente nas características específicas de cada local (Bradford, 2011) assim como através de relações subjetivas e objetivas de proximidade (Laville, 2005; 2009). Trata-se de saber que tipo de respostas é dado por estas organizações, que recursos mobilizam e qual a sua importância na construção da vida da cidade. Tal análise será feita pela sistematização dos elementos mais inovadores da acção, lidos a partir de duas dimensões: i) dos resultados; ii) das formas de organização e de gestão. Apresentam-se os casos mais emblemáticos que refletem a capacidade de auto-organização cidadã para a criação de respostas diretas aos problemas emergentes da cidade.
    2012-06Journal article Open Access Show more
  • The first evidence of Paleolithic portable art in southern Portugal
    Publication . Simon Vallejo, Maria D.; Cortes Sanchez, Miguel; Bicho, Nuno Gonçalo Viana Pereira Ferreira
    This paper presents the first evidence for Palaeolithic portable art in Southern Portugal. This include two plaques, dated between 20,500 and 19,500 BP from Solutrean levels from the site of Vale Boi, Western Algarve (Portugal). One of the pieces is a small engraved schist plaque (14,6 x 8,1 mm) with abstract lines on one side. The other artefact is an 8 x 5 cm schist plaque. One side is an oxide natural deposit, used to produce dye; the other side has three aurochs and a probable cervid. Stilistic information and the engraving sequence indicate probably production by a single artist. The stylistic characteristics are in full agreement withi those from late Gravettian and early Solutrean art known from Valencia, Andalucia (Spain) and the Coa valley (Portugal), thus confirming the absolute AMS dates from the Vale Boi Levels.
    2012-06Journal article Open Access Show more
  • Seawater acidification by CO2 in a coastal lagoon environment: Effects on life history traits of juvenile mussels Mytilus galloprovincialis
    Publication . Ben-Hamadou, Radhouan; Range, Pedro; Piló, David
    The carbonate chemistry of seawater fromthe Ria Formosa lagoon was experimentallymanipulated, by diffusing pure CO2, to attain two reduced pH levels, by−0.3 and−0.6 pH units, relative to unmanipulated seawater. After 84 days of exposure, no differences were detected in terms of growth (somatic or shell) or mortality of juvenile mussels Mytilus galloprovincialis. The naturally elevated total alkalinity of the seawater (≈3550 μmol kg−1) prevented under-saturation of CaCO3, evenunder pCO2 values exceeding 4000 μatm, attenuating the detrimental effects on the carbonate supply-side. Even so, variations in shell weight showed that net calcification was reduced under elevated CO2 and reduced pH, although the magnitude and significance of this effect varied among size-classes. Most of the loss of shell material probably occurred as post-deposition dissolution in the internal aragonitic nacre layer. Our results show that, even when reared under extreme levels of CO2- induced acidification, juvenileM. galloprovincialis can continue to calcify and grow in this coastal lagoon environment. The complex responses of bivalves to ocean acidification suggest a large degree of interspecific and intraspecific variability in their sensitivity to this type of perturbation. Further research is needed to assess the generality of these patterns and to disentangle the relative contributions of acclimation to local variations in seawater chemistry and genetic adaptation.
    2012-06Journal article Restricted Show more