136 research outputs found

    Programa Polis para a Frente Ribeirinha de Setúbal: avaliação quantitativa do espaço público de 1900 a 2013

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    The modern conversion of cities waterfronts must take into consideration the urban design of the city, through a holistic vision of the territory. In the conversion process the public space is the fundamental element capable of integrating the “new city” with the existing urban fabric. An analysis of the public space of the Setúbal waterfront over the years is presented in this paper, with particular focus on the years following the execution of the Polis Programme. A quantitative approach was undertaken and the public spaces data was treated mathematically. This paper shows how the Polis programme contributed towards the increase of public space of the Setúbal waterfront and contributed for the conversion of those spaces according to the best European practices for the conversion of waterfronts. With the construction of new public spaces and the conversion of existing public spaces, the Polis programme contributed to a greater connection of the city of Setúbal with the river Sado and concretized a vision of integration of the waterfront that was present in the 1931 plan.info:eu-repo/semantics/publishedVersio

    Peritoneal Dialysis in the elderly: challenge accepted

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    At present, mostly in Western countries, age is no longer an absolute limitation for renal replacement therapy (RRT); however, some elderly patients are still not considered for peritoneal dialysis (PD), mainly due to late referral, social isolation, low functional capacity or lower life expectancy. In this review, we address the challenges posed by older patients on PD programs, focusing on a SWOT (strengths, weaknesses, opportunities and threats) analysis and illustrate how PD may have successful outcomes in this population, worldwide and in Portugal. Finally, we will enumerate strategies to overcome the barriers to this technique. From January to December 2017, we conducted a systematic review of the literature using MEDLINE, the Cochrane Library and Web of Knowledge. Studies on PD and HD were included. All searches were limited to English and Portuguese and were augmented by review of bibliographic references from the studies included. Findings concerning modality superiority and better outcome in older people are still scarce and controversial, however according to several well-established PD programs worldwide, including assisted PD, elderly patients presented similar technique survival, hospitalization rates and frequency of peritonitis as compared to younger PD patients and HD patients. As expected, older patients had higher mortality though, especially in patients with more comorbidities. On the other hand, PD was associated with less cognitive loss and showed benefit in perceived quality of life. In Portugal, the low utilization of PD and the patients’ age discrepancy between both modalities explains the limited literature and the discrepante results (some studies show lower peritonitis rate, superior technique and patient survival and others presente higher hospitalization episodes and mortality rates); however, it appears to be a good (cost-effective) option for elderly patients. Overall, PD is an equally suitable modality for elderly patients in the long term.info:eu-repo/semantics/publishedVersio

    Therapeutic Approach to Parapneumonic Effusions and Empyemas

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    Face à inexistência de uma metodologia única e consensual na abordagem terapêutica dos derrames pleurais parapneumónicos e empiemas, os autores propõem um protocolo de orientação, que resultou da reflexão baseada na sua experiência e na bibliografia mais recente

    Clear-water scour at comparatively large cylindrical piers

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    New long-duration clear-water scour data were collected at single cylindrical piers with the objective of investigating the effect of sediment coarseness, Dp=D50 (Dp = pier diameter; D50 = median grain size) on the equilibrium scour depth and improving the scour depth time evolution modeling by making use of the exponential function suggested in the literature. Experiments were carried out for the flow intensity close to the threshold condition of initiation of sediment motion, imposing wide changes of sediment coarseness and flow shallowness, d=Dp (d = approach flow depth). The effect of sediment coarseness on the equilibrium scour depth was identified; existing predictors were modified to incorporate this effect for U=Uc ≈ 1.0; Dp=D50 > ≈60 and d=Dp ≥ 0.5; the complete characterization of a known scour depth time evolution model was achieved for U=Uc ≈ 1.0, 60 < Dp=D50 < 500 and 0.5 ≤ d=Dp ≤ 5.0

    Estratégias para a gestão da água em espaços verdes: Jardins complexos vs relvados.

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    Os espaços verdes urbanos são hoje em dia bastante comuns em qualquer ambiente Mediterrâneo, em forma de jardins complexos e/ou relvados, ocupando em alguns casos vastas áreas. A estratégia de gestão da água irá proporcionar a sua manutenção de acordo com os padrões de qualidade visual requeridos. Atendendo a que, estes espaços não visam a produção máxima de biomassa então, a estratégia para a gestão da água de rega não deverá ser a mesma da utilizada na produção de alimentos. A rega dos relvados deverá ser estabelecida com base no conhecimento da evapotranspiração da paisagem (ETL, mm/dia), função da evapotranspiração de referência (ETo, mm) e do coeficiente da paisagem (KL). A gestão da rega deverá ser estabelecida atendendo às características do solo existente no local. Nos jardins complexos onde existem misturas de plantas com diferentes exigências em água (com diferentes valores de KL) a gestão da rega torna-se mais complicada. Este estudo visa assim classificar as diferentes áreas verdes existentes em ambiente Mediterrâneo e mostrar de que forma é possível melhor adequar as estratégias de rega à gestão da água em relvados e jardins complexos, atendendo às diferentes necessidades hídricas das plantas, de forma a torná-los mais sustentáveis numa região sujeita a escassez hídrica.info:eu-repo/semantics/publishedVersio

    Electrical properties of cork and derivates

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    The electrical properties of natural cork, commercial cork agglomerates (for floor and wall covering) and a composite of cork/TetraPak® were studied. The composite was developed at LNEG/Portugal and is made of recycled cork and TetraPak® containers. Measurements of isothermal charge and discharge currents (ICC/IDC) and dielectric relaxation spectroscopy (DRS) were made. The isothermal currents characteristics and the samples electrical conductivity were investigated under different conditions (electric field, temperature and measuring atmosphere). Dielectric relaxation spectroscopy was used to quantify the changes in the permittivity with the samples conditioning. Both experimental techniques showed the strong influence of water content on the electrical properties of cork and its derivatives

    Caracterização e medidas mitigadoras das inundações em Vilamoura, Algarve

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    Este artigo visa analisar as inundações da Ribeira do Vale Tesnado, zona poente de Vilamoura (Algarve), e as soluções integradas que geram a diminuição da probabilidade e da magnitude das mesmas. Para tal, esta análise foi dividida em quatro etapas: i) estudo hidrológico da bacia hidrográfica a montante, com vista à determinação de caudais de cheia; ii) estudo hidrodinâmico, no qual se efetua a modelação numérica do escoamento na zona com risco potencial significativo, considerando o efeito das diversas estruturas hidráulicas existentes; iii) identificação dos níveis atingidos pela inundação associada a períodos de retorno de 10 e 100 anos e mapeamento das áreas inundáveis; iv) análise de resultados e identificação de soluções integradas com vista à minimização da frequência e da magnitude das inundações. A aferição do modelo foi realizada através da comparação dos níveis de cheia observados a 8 de novembro de 2012 (com base em testemunhos locais, marcas de cheia, fotografias e vídeos) com os obtidos da modelação numérica.info:eu-repo/semantics/publishedVersio

    Can heart tissue fatty acid profile be used as a tool to discriminate sea lamprey (Petromyzon marinus, L.) populations in several Portuguese river basins?

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    This study proposes to evaluate the use of heart tissue fatty acid signature and multivariate analysis of fatty acid profile as a possible discriminating tool for sea lamprey P. marinus populations sampled in Portuguese river basins. Local fisherman collected adult sea lampreys in eight Portuguese river basins (Minho, Lima, Cávado, Douro, Vouga, Mondego, Tagus and Guadiana) at the beginning of their spawning migration. Heart total lipid extraction was obtained by accelerated solvent extraction (ASE) and FAMEs were prepared by transesterification with methanol-boron trifluoride and analysed by GC. FAMEs were identified by comparison of their retention times with known standards chromatographed in identical gas chromatography conditions. The fatty acid profile of the heart tissue varied among the individuals of the different river basins. In order to identify which fatty acid contributed most to the differences between river basins heart tissue, MDA was employed. The MDA proved to be statistically significant and the overall corrected classification rate estimated from cross-validation procedure was 86.2%. Although in the case of the individuals of Tagus and Guadiana 100% and 94.7 % of subjects were correctly classified, respectively, there are always a few individuals of the other 5 watersheds that have characteristics identical to those observed in these two river basins.The results are discussed in terms of fatty acid origin and hypothesis concerning the migratory behavior that could lead to these results. The fatty acid profile of heart is considered more stable than other organs, but it still exhibits some variability. This study seems to point out the potential for fatty acid compositions to discriminate sea lampreys from Portuguese river basins, which are probably related with environmental variables that they may have been exposed during early stages of their life cycle

    Can the mitochondrial malondialdehyde content be an useful tool to distinguish ecological quality of Petromyzon marinus habitat?

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    The sea lamprey is an anadromous species that migrates twice during its life cycle between freshwater and seawater. Microphagous larvae generally spend 4–5 years burrowed in the substrate of rivers and streams before undergoing metamorphosis that ends with the beginning of the juvenile trophic migration. Once metamorphosis is complete, sea lamprey juvenile downstream migrants are fully tolerant to 35 PSU seawater. Pollution resulting from industrial effluents may disturb the seawater acclimatization causing oxidative damages, and ultimately may lead to a decrease of sea lamprey population. The aim of this study was to compare salt acclimation of sea lamprey juveniles captured in river basins with different levels of aquatic pollution, using mitochondrial glutathione and malondialdehyde of gills and liver as markers of physiological stress and cell damages. The results showed that juveniles from Lima basin exhibited the highest levels of mitochondrial malondialdehyde in gills, even though significant changes in the stress markers of mitochondrial gills of all animals subject to salt acclimation were not detected. In addition, an increase in the oxidative damages of hepatic mitochondria of macrophthalmia from Vouga basin suggests the occurrence of metabolic failures with the potential to disturb the capacity to adaptation to the marine environment

    Hepatic mitochondrial content in malondialdehyde may be a marker of sea lamprey contact with atrazine

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    The atrazine attracts special attention as pollutant because of itspersistence in the aquatic environment. Although this herbicide has been studied in teleost, its toxicity in the sea lamprey, Petromyzon marinus is still poorly understood. Oxidative stress may occur if chemical pollutants contribute to block the capacity of mitochondria to generate ATP with continuous production of reactive oxygen species (ROS), disturbing the success of P. marinus seawater acclimation. So, the aim of this study was to evaluate how atrazine influences the malondialdehyde (MDA), glutathione (GSH) and glutathione disulfide (GSSG) contents of gills and liver mitochondria of juveniles from Lima river basin, Portugal during salt acclimation. Sampling occurred at the beginning of the P. marinus downstream migration. The sampled juveniles were transported alive to the laboratory and maintained in 200 l tanks with LSS 8 life support system. Two groups of 40 specimens were hold in tanks with 50 or 100 lg/l atrazine, during 30 days. The salinity was gradually increased from 0 to 35 psu,following a three step procedure during a 30 days period. The control group was maintained in freshwater without atrazine. Mitochondria obtained by centrifugation at 15000 g, 30 min, 4°C, of tissues homogenates prepared in 50 mM Tris-HCl pH 7.5 buffer were used in determination of ROS, MDA, GSH and GSSG by fluorescence. The statistical analysis were performed by ANOVA I and Duncan (p < 0.05), using SPSS 22 for Windows.The results showed that in P. marinus juveniles, no significant changes in the markers of oxidative stress and cell damages were detected in the mitochondrial gills. Nevertheless, in the animals exposed to 50 lg/l atrazine the content in glutathione and GSSG increased. A similar pattern of stress markers was detected in hepatic mitochondria. However, in the presence of atrazine, the MDA level of the mitochondria of liver increased threefold in the animals during salt acclimation. The high level of mitochondrial damages, detected in the hepatic mitochondria of macrophthalmia treated with atrazine, suggests that herbicide exposure caused metabolic failures which can disturb the adaptation of these specimens to the oceanic feeding phase. The hepatic mitochondrial MDA levels of P. marinus, may eventually detect sea lamprey contact with chlorine herbicides
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