Efeitos das alterações climáticas e da subida do nível do mar nos aquíferos costeiros

Neste trabalho descrever-se-ão os efeitos da subida do nível do mar no planeamento e gestão dos sistemas de captação da água doce disponível nas regiões costeiras. Recordar-se-ão as leis que regem o escoamento subterrâneo nos aquíferos do litoral e as metodologias para a procura das melhores políticas de extracção da água doce. Apresenta-se o modelo de gestão que é composto pela associação de uma técnica de optimização e de modelos de simulação do comportamento do aquífero. O modelo de optimização-simulação determina as extracções máximas permitidas a um conjunto de captações para cada cenário de subida do nível do mar, do escoamento natural no aquífero, do local de implantação e da distância de segurança entre o pé da interface água doce / água salgada e o ponto de controlo. Os efeitos na redução das extracções face à projectada subida do nível do mar e da diminuição do escoamento natural no aquífero, para que seja mantida a distância de segurança pretendida, são diversos em função do local de implantação. As superfícies e as curvas das extracções máximas em função da subida do nível do mar e do local de implantação evidenciam a necessidade dum adequado planeamento dos locais de construção das captações que antecipadamente evite os efeitos das alterações climáticas.Fundação para a Ciência e a Tecnologia (FCT

Optimal management of groundwater withdrawals in coastal aquifers

In this work, an optimisation model has been developed for planning and managing saltwater-intruded coastal aquifer systems. We apply this model, which uses the simulation / optimisation approach, for managing water resources in coastal areas. The management model finds the best policies to maximize the present value of economic results of meeting water demands and to keep under control the saltwater intrusion. The idea of security distance to a control point provides the establishment of a trade-off relationship between the increased management cost and the desired level of protection. The model was applied to a typical case with interesting results. It was also crucial to have an understanding of the tradeoffs between groundwater withdrawals, positions of the wells from the coast line, and the security distance. This model allows the sustainable use of coastal water resources

Avaliação colaborativa em biologia: um tempo de aula transformado em tempo de aprendizagem

O reconhecimento da importância da promoção da construção de uma visão da avaliação como um exercício ético que implica o aluno numa ação de reflexão, de interdependência positiva, de compromisso e de corresponsabilidade, e da transformação de um tempo de práticas de avaliação em tempo de aprendizagem, conduziu à idealização, conceção, implementação e avaliação de uma estratégia de intervenção pedagógica assente, fundamentalmente, em processos de auto e heteroavaliação num contexto colaborativo. A intervenção pedagógica desenvolveu-se na temática Fotossíntese da disciplina de Biologia e Geologia do 10º ano de escolaridade do Curso Científico-Humanístico de Ciências e Tecnologias. Foi concretizada no 2º período do ano letivo de 2011/2012 com uma turma de 29 alunos de uma Escola Secundária/3, localizada no distrito de Braga, na região norte de Portugal. A consecução dos processos de auto e heteroavaliação efetuou-se através da operacionalização conjunta em quatro atividades de aprendizagem, concebidas segundo uma estrutura dialógica, orientada para a resolução de um problema/situação problemática e, consequentemente, para a compreensão do respetivo conhecimento substantivo. Uma primeira avaliação do impacto educativo da estratégia de intervenção pedagógica evidencia um efeito na (re)construção das perspetivas dos alunos sobre o valor da heteroavaliação na aprendizagem. Os resultados encontrados reforçam a importância da implementação de atividades de aprendizagem focalizadas na reflexão sobre o papel da avaliação na aprendizagem

Study, design and development of a new add-on function for the FRICTORQ® - Friction Test Instrument

The assessment of handle properties is of utmost importance in materials in our everyday life. There is a wide range of materials there are used in contact with the human skin, which may cause several unpleasant skin reactions. The FRICTORQ® is a laboratory equipment developed by the authors to measure the friction coefficient in fabrics, to enable a quantitative assessment of touch/handle, in order to predict the comfort behaviour of 2D/3D structures when used or touched by humans. In a further development, the FRICTORQ® was redesigned to accommodate a new testing kit function to determine the friction coefficient of fabrics in a liquid environment. This new design will be explained and the results obtained while testing different swimwear fabrics and hospital garments will be also presented and discussed

Surface photochemistry: benzophenone as a probe for the study of silica and reversed-phase silica surfaces

This work reports the use of benzophenone, a very well characterized probe, to study new hosts: two reversed-phase silicas. Laser-induced room temperature luminescence of argon purged solid powdered samples of benzophenone adsorbed onto the two different reversed-phase silicas, RP-18 and RP-8, revealed the existence of a low energy emission band in contrast with the benzophenone adsorbed on 60 A pore silica, where only triplet benzophenone emits. This low energy emission band was identified as the fluorescence of the ketyl radical of benzophenone, which is formed as the result of a hydrogen atom abstraction reaction of the triplet excited benzophenone from the alkyl groups of the surface of the reversed silicas. Such emission does not exist for benzophenone adsorbed onto 60 A pore silica. Room temperature phosphorescence was obtained in argon purged samples for all the surfaces under use. The decay times of the benzophenone emission vary greatly with the alkylation of the silica surface when compared with "normal" silica surface. A lifetime distributions analysis has shown that the shortest lifetimes for the benzophenone emission exist in the former case. Triplet-triplet absorption of benzophenone was detected in all cases and is the predominant absorption in the case of 60 A pore silica, while benzophenone ketyl radical formation occurs in the case of the reversed silicas. Diffuse reflectance laser. ash photolysis and gas chromatography-mass spectrometry techniques provided complementary information, the former about transient species and the latter regarding the final products formed after laser irradiation, both at 266 nm or 355 nm. Product analysis and identification show that the degradation photoproducts are dependent on the excitation wavelength, the photochemistry being much more rich and complex in the 266 nm excitation case, where an alpha-cleavage reaction occurs. A detailed mechanistic analysis is proposed

Surface photochemistry: photodegradation study of pyrene adsorbed onto microcrystalline cellulose and silica

Ground-state diffuse reflectance, time resolved laser-induced luminescence, diffuse reflectance laser flash-photolysis transient absorption and chromatographic techniques were used to elucidate the photodegradation processes of pyrene adsorbed onto microcrystalline cellulose and silica. Ground-state diffuse reflectance showed that on both substrates low concentrations display absorption of pyrene monomers. At high concentrations spectral changes attributed to aggregate formation were observed. Laser induced fluorescence showed that pyrene onto microcrystalline cellulose mainly presents fluorescence from monomers, while for silica, excimer-like emission was observed from low surface loadings (greater than or equal to 0.5 mumol g(-1)). Transient absorption and photodegradation studies were performed at concentrations where mainly monomers exist. On silica, pyrene presents transient absorption from its radical cation. On microcrystalline cellulose both radical cation, radical anion and pyrene triplet-triplet absorption were detected. Irradiation followed by chromatographic analysis showed that pyrene decomposes on both substrates. For pyrene on microcrystalline cellulose 1-hydroxypyrene was the main identified photoproduct since in the absence of oxygen further oxidation of 1-hydroxypyrene was very slow. For pyrene on silica photodegradation was very efficient. Almost no 1-hydroxypyrene was detected since in the presence of oxygen it is quickly oxidized to other photooxidation products. On both substrates, pyrene radical cation is the intermediate leading to photoproducts and oxygen it is not involved in its formation

Evaluation of the Performance of Three Spacers

Agradecimentos às empresas GlaxoSmithKline (Portugal) e Astrazeneca (Suécia), pela cedência das câmaras de expansão Volumatic ® e NebuChamber®, respectivamente.Introdução: Existem vários factores que afectam a distribuição do fármaco nas vias áreas inferiores, onde podemos destacar os factores associados ao próprio dispositivo de inalação. Este trabalho tem como objectivo avaliar o desempenho da libertação de fármaco em três câmaras de expansão, assim como a quantidade de agente activo depositada no seu interior. Materiais e Métodos: Foi utilizado o Impinger Líquido de vários estágios (MSLI) de modo a avaliar o comportamento das partículas da suspensão Ventilan®HFA acoplado a três câmaras de expansão (Volumatic®, AeroChamber MAX® e NebuChamber®), de acordo com a Farmacopeia Portuguesa. A massa de sulfato de salbutamol recolhida nos diferentes compartimentos do impinger e no corpo da câmara foi determinada por espectrofotometria de modo a determinar a percentagem de massa cumulativa para cada câmara, determinando-se a fracção de partículas finas. Utilizou-se a Análise de Variância simples (One-way ANOVA) com o teste Post-Hoc de Bonferroni para a comparação dos resultados. Resultados: A deposição do sulfato de salbutamol ocorreu fundamentalmente no corpo das três câmaras, aproximadamente entre 40 a 50 %. Esta deposição é ligeiramente inferior na NebuChamber® (média±desvio-padrão: 43,8 % ± 11,6 %), mas não significativa relativamente à Volumatic® (p=0,351) ou à AeroChamber MAX® (p=0,115). A fracção de partículas finas assume valores de: 28,2 % ± 4,1 %, 29,6 % ± 2,4 % e 30,9 % ± 6,7 % para a Volumatic®, AeroChamber MAX® e NebuChamber®, respectivamente. Conclusão: As câmaras de expansão estudadas apresentam eficácias semelhantes na veiculação de sulfato de salbutamol aos estágios mais inferiores, não tendo sido encontrada relação entre os resultados e as suas características de volume, forma e material constituinte. Deste modo, a Volumatic® aparenta ser a câmara ideal para um hospital, uma vez que o seu grande volume não constitui uma desvantagem, sendo que o seu preço, inferior relativamente às anteriores, constitui uma vantagem de extrema importância para os hospitais públicos.Introduction: Several aspects are known to influence the drug distribution within the low respiratory tract, with particular emphasis on those related to the inhalation device. The aim of this work was to assess the performance of three spacers in the drug release, and also the quantity of active agent deposited inside these devices. Materials and Methods: In order to evaluate the behaviour of particles in suspension delivered through the Ventilan®HFA inhaler coupled to three different spacers (Volumatic®, AeroChamber MAX® and NebuChamber®) the Multistage Liquid Impinger (MSLI) was used, according to the Portuguese Pharmacopoeia. The mass of salbutamol sulphate deposited on the different impinger compartments and inside the spacer was determined by spectrophotometry, with the purpose of determining the percentage of cumulative mass for each spacer, and then the fine particle fraction. The results were compared statistically using a one-way analysis of variance (one-way ANOVA) with a Bonferroni post-hoc test. Results: About 40 to 50% of salbutamol sulphate was found deposited in the body of the three spacers. This deposition was slightly lower for NebuChamber® (average ± standard deviation of 43.8 % ± 11.6 %), in relation to Volumatic® (p=0.351) or AeroChamber MAX® (p=0.115). The fine particle fraction reached values of 28.2 ± 4.1%, 29.6 ± 2.4% and 30.9 ± 6.7% for Volumatic®, AeroChamber MAX® and NebuChamber®, respectively. Conclusion: The spacers showed to have similar efficiencies in the delivery of salbutamol sulphate in the last stages, and there was no relation between the results and the spacers characteristics such as volume, shape and material. Therefore, Volumatic® appears to be perfect for hospital use, since its big volume does not constitute a disadvantage, and its lower cost, when compared to the remaining two spacers, represents an advantage of utmost importance for public hospital

Photon rings as tests for alternative spherically symmetric geometries with thin accretion disks

The imaging by the Event Horizon Telescope (EHT) of the supermassive central objects at the heart of the M87 and Milky Way (Sgr A$^\star$) galaxies, has marked the first step into peering at the shadow and photon rings that characterize the optical appearance of black holes surrounded by an accretion disk. Recently, Vagnozzi et. al. [S.~Vagnozzi, \textit{et al.} arXiv:2205.07787 [gr-qc]] used the claim by the EHT that the size of the shadow of Sgr A$^\star$ can be inferred by calibrated measurements of the bright ring enclosing it, to constrain a large number of spherically symmetric space-time geometries. In this work we use this result to study some features of the first and second photon rings of a restricted pool of such geometries in thin accretion disk settings. The emission profile of the latter is described by calling upon three analytic samples belonging to the family introduced by Gralla, Lupsasca and Marrone, in order to characterize such photon rings using the Lyapunov exponent of nearly bound orbits and discuss its correlation with the luminosity extinction rate between the first and second photon rings. We finally elaborate on the chances of using such photon rings as observational discriminators of alternative black hole geometries using very long baseline interferometry.Comment: 17 pages, 58 figures/image

Comparative Metabolomics Study of the Impact of Articaine and Lidocaine on the Metabolism of SH-SY5Y Neuronal Cells

Articaine (ATC) and lidocaine (LDC) are the local anesthetics (LAs) currently most employed in dentistry. Cases of paresthesia, reported more frequently for ATC, have raised concerns about their potential neurotoxicity, calling for further investigation of their biological effects in neuronal cells. In this work, the impact of ATC and LDC on the metabolism of SH-SY5Y cells was investigated through 1H NMR metabolomics. For each LA, in vitro cultured cells were exposed to concentrations causing 10 and 50% reductions in cell viability, and their metabolic intracellular and extracellular profiles were characterized. Most effects were common to ATC and LDC, although with varying magnitudes. The metabolic variations elicited by the two LAs suggested (i) downregulation of glycolysis and of glucose-dependent pathways (e.g., one-carbon metabolism and hexosamine biosynthetic pathway), (ii) disturbance of branched chain amino acids (BCAA) catabolism, (iii) downregulation of TCA cycle anaplerotic fueling and activation of alternative energy producing pathways, (iv) interference with choline metabolism and (v) lipid droplet build-up. Interestingly, LDC had a greater impact on membrane phospholipid turnover, as suggested by higher phosphatidylcholine to phosphocholine conversion. Moreover, LDC elicited an increase in triglycerides, whereas cholesteryl esters accumulated in ATC-exposed cells, suggesting a different composition and handling of lipid droplets.publishe