1,138 research outputs found

    Prediction of overwash in alongshore variable barrier islands [Previsão da ocorrência de galgamentos em ilhas barreira com variabilidade longilitoral]

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    Overwash prediction is very important for coastal zone management. This work intends to identify alongshore variations in storm impact and evaluate the role of sub-aerial and submerged morphologies in overwash occurrence. For this study, 24 cross-shore topo-bathymetric profiles were set on Barreta Island (Ria Formosa barrier island system, Portugal). Pre- and post-overwash surveys were made between August 2012 and April 2013. During overwash events, tidal levels and wave parameters at breaking were obtained. Overwash occurred under storm and non-storm conditions, the latter coincident with spring high-tide. Beach morphology was spatially variable, and changeable from one overwash episode to the next. Predictions of overwash occurrence were made using the Overwash Potential, defined as the difference between runup and barrier elevation. Several runup equations were tested, and the results compared to the actual observations. The selected predictor provided an accuracy of 88% for the identification of the locations where overwash occurred. This study proves that nearshore and foreshore morphologies have a major impact on the longshore distribution of overwash.info:eu-repo/semantics/publishedVersio

    Reproductive activity and biochemical composition of the pullet carpet shell Venerupis senegalensis (Gmelin, 1791) (Mollusca: Bivalvia) from Ria de Aveiro (northwestern coast of Portugal)

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    The present study characterizes the reproductive cycle of Venerupis senegalensis (=V. pullastra) from Ria de Aveiro (Portugal) as well as its nutrient storage and exploitation strategy. The reproductive cycle followed a seasonal cycle that correlated negatively with sea surface temperature, and comprised a ripe stage in winter followed by a spawning period that began in late winter and ended in the early summer. This extended spawning may be an advantageous strategy for the species because it ensures a continuous supply of settlers. Gametogenesis began in late summer/early autumn and intensified with the decrease in temperature during autumn. The condition index increased even during the spawning period, which indicates that there is rapid recovery and that reserves are accumulated during late summer and used later in the gametogenic process. Proteins did not contribute significantly to gametogenesis and the glycogen pattern is typical of conservative species, since gametogenesis depends largely on the amount of glycogen stored. The lipid storage and utilization cycle showed that gametogenesis took place in autumn/winter and that energy reserves were accumulated in summer

    Actividad reproductiva y composición bioquímica de la almeja babosa Venerupis senegalensis (Gmelin, 1791) (Mollusca: Bivalvia) de la Ría de Aveiro (costa noroeste de Portugal)

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    The present study characterizes the reproductive cycle of Venerupis senegalensis (=V. pullastra) from Ria de Aveiro (Portugal) as well as its nutrient storage and exploitation strategy. The reproductive cycle followed a seasonal cycle that correlated negatively with sea surface temperature, and comprised a ripe stage in winter followed by a spawning period that began in late winter and ended in the early summer. This extended spawning may be an advantageous strategy for the species because it ensures a continuous supply of settlers. Gametogenesis began in late summer/early autumn and intensified with the decrease in temperature during autumn. The condition index increased even during the spawning period, which indicates that there is rapid recovery and that reserves are accumulated during late summer and used later in the gametogenic process. Proteins did not contribute significantly to gametogenesis and the glycogen pattern is typical of conservative species, since gametogenesis depends largely on the amount of glycogen stored. The lipid storage and utilization cycle showed that gametogenesis took place in autumn/winter and that energy reserves were accumulated in summer.El presente estudio caracteriza el ciclo reproductivo de Venerupis senegalensis (= V. pullastra) en la Ría de Aveiro (Portugal) así como su estrategia de almacenamiento y explotación de los nutrientes. El ciclo reproductivo de esta especie sigue un ciclo estacional que se correlaciona negativamente con la temperatura del agua del mar, que coincide con un estado de madurez en el invierno, seguido de un periodo de desove que se inicia a finales de invierno y termina a principios del verano. Este periodo de puesta prolongado puede ser una estrategia ventajosa para la especie, ya que garantiza un suministro continuo de larvas. La gametogénesis comenzó a finales del verano/inicios de otoño y se intensificó con la disminución de la temperatura durante el otoño. El aumento del índice de condición, todavía durante la puesta, indica una recuperación rápida y una acumulación de reservas a finales del verano, que serán utilizadas en el siguiente proceso de gametogénesis. Las proteínas no contribuyen significativamente a la gametogénesis y el ciclo de glucógeno es típico de las especies conservadoras, una vez que la gametogénesis depende, en gran medida, de la cantidad de glucógeno almacenado. El almacenamiento de lípidos y su utilización indica la gametogénesis en el otoño/invierno, así como el proceso de acumulación de energía en verano

    Antioxidant activity and cytotoxicity of solubilized C60 and its conjugates with butylated hydroxytoluene

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    It has been described that fullerenes (C60) present interesting properties with potential application in clinical conditions related to oxidative stress. One of the most prominent features of fullerenes is the ability to quench free radicals. However, because of its poor solubility, this has been studied mostly in organic solutions, while the antioxidant activity and cytotoxicity of fullerenes and their derivates in aqueous medium is not well characterized. The antioxidant capacity of synthesised C60-conjugates has been investigated and its was higher comparing to C60 isolated. The aim of this study was to assess the viability of C60-conjugates by determining its antioxidant activity and cytotoxicity in bio-relevant media

    Electrochemical Behavior and Determination of Fluconazole

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    The electrochemical behavior of fluconazole showed an irreversible oxidation process, with the electrochemical - chemical mechanism being highly dependent on the electrode material. Adsorption of reagent at positive applied potential was observed at Pt electrode while preferential adsorption of the oxidation products was observed at Glassy Carbon surfaces. In pH below 7.0, the anodic current process was intensively decreased. At carbon paste electrode, the fluconazole oxidation current, recorded in phosphate buffer solution (pH 8.0), changed linearly with the fluconazole concentration, Ipa = 5.7×10-5 (mA) × 0.052 [Fluconazol] (μg mL-1), in the range of 48.0 to 250.0 μg mL-1. The detection limit obtained was 6.3 μg mL-1.O comportamento eletroquímico do fluconazol demonstrou oxidação irreversível com mecanismos eletroquímicos-químicos dependentes do material eletródico. Em eletrodos de Pt observou-se adsorção do reagente sob a aplicação de potenciais positivos, enquanto adsorção preferencial dos produtos foi observada em eletrodo de carbono vítreo. Em valores de pH inferiores a 7,0, a corrente do processo anódico é intensamente diminuída. Em eletrodo de pasta de carbono e tampão fosfato, pH 8,0, a corrente de oxidação variou linearmente com a concentração de fluconazol em solução, Ipa = 5,7×10-5 (mA) × 0,052 [Fluconazol] (μg mL-1), no intervalo de 48,0 a 250,0 μg mL-1. O limite de detecção obtido foi 6,3 μg mL-1.FAPES

    Modelos locais de governação na educação

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    A descentralização de competências na área da educação assume, na atualidade, uma grande pertinência e relevância, para as autarquias e para os agrupamentos e escolas não agrupadas. Os modos de regulação da ação educativa local e territorial tanto podem corresponder a um padrão de domínio e de subordinação ou a um padrão de participação, de co-autoria ou regulação sociocomunitária. Esta é a ambivalência, a ambiguidade, a incerteza central que podem colocar em crise a ação do Estado enquanto garante último da justiça, da democracia e da equidade. Com o trabalho de investigação pretendemos estudar os diferentes modelos de governação, na área da educação, adotados em diferentes municípios, para conseguir analisar como é que esses modelos contribuem para o desenvolvimento das pessoas, das organizações e dos contextos locais. Para a realização da investigação sobre os diferentes modelos de governação, na área da educação, iremos considerar os 17 municípios da AMP e os agrupamentos e escolas não agrupadas desses mesmos municípios. A metodologia de investigação assumirá uma natureza mista. Através da metodologia qualitativa pretende-se produzir uma revisão sistemática de literatura, investir no trabalho de campo, com inquéritos por entrevista aos presidentes das câmaras municipais dos 17 municípios da AMP, complementando com uma análise documental das cartas educativas, dos regimentos e das atas dos conselhos municipais de educação, dos projetos educativos municipais, caso existam. Na metodologia quantitativa pretende-se inquerir por questionário os diretores e presidentes do Conselho Geral dos agrupamentos de escolas e escolas não agrupadas da AMP. Perspetiva-se que se encontrem várias formas de governação, desenhando-se três tipos possíveis: uma regulação sociocomunitária, uma regulação municipalista, e uma regulação centralista de natureza ambígua, tornando incerto o sentido do desenvolvimento da educação no território.info:eu-repo/semantics/publishedVersio

    Commercial Gold Complexes Supported on Functionalised Carbon Materials as Efficient Catalysts for the Direct Oxidation of Ethane to Acetic Acid

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    UIDB/00100/2020 UIDP/00100/2020 LA/P/0056/2020 IST-ID/119/2018 SFRH/BD/146426/2019 CEEC-INST/00102/2018 UIDB/50006/2020 UIDP/50006/2020 Base-UIDB/50020/2020 Programmatic-UIDP/50020/2020The single-pot efficient oxidation of ethane to acetic acid catalysed by Au(I) or Au(III) compounds, chlorotriphenylphosphinegold(I) (1), chlorotrimethylphosphinegold(I) (2), 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidenegold(I) chloride (3), dichloro(2-pyridinecarboxylato)gold(III) (4), homogenous and supported on different carbon materials: activated carbon (AC), multi-walled carbon nanotubes (CNT) and carbon xerogel (CX), oxidised with nitric acid followed by treatment with NaOH (-ox-Na), is reported. The reactions were performed in water/acetonitrile. The materials were selective for the production of acetic acid, with no trace of by-products being detected. The best homogenous catalysts were complexes 2 and 3 which showed the highest ethane conversion and an acetic acid yield of ca. 21%, followed by 4 and 1. The heterogenised materials showed much better activity than the homogenous counterparts, with acetic acid yields up to 41.4% for 4@CNT-ox-Na, and remarkable selectivity (with acetic acid being the only product detected). The heterogenised catalysts with the best results were reused up to five cycles, with no significant loss of activity, and maintaining high selectivity for acetic acid. 4@CNT-ox-Na showed not only the best catalytic activity but also the best stability during the recycling runs.publishersversionpublishe

    Microwave Synthesis of Visible-Light-Activated g-C3N4/TiO2 Photocatalysts

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    Funding Information: This work was financed by national funds from FCT-Fundação para a Ciência e a Tecnologia, I.P., within the scope of projects UI/BD/151292/2021 (Ph.D. research scholarship), LA/P/0037/2020, UIDP/50025/2020 and UIDB/50025/2020 of the Associate Laboratory Institute of Nanostructures, Nanomodelling, and Nanofabrication-i3N, but also the 2021.03825.CEECIND. Acknowledgments are also given to the EC project SYNERGY H2020-WIDESPREAD-2020-5, CSA, proposal nº 952169, EMERGE-2020-INFRAIA-2020-1, proposal nº 101008701, and to the European Community’s H2020 program under grant agreement No. 787410 (ERC-2018-AdG DIGISMART). Publisher Copyright: © 2023 by the authors.The preparation of visible-light-driven photocatalysts has become highly appealing for environmental remediation through simple, fast and green chemical methods. The current study reports the synthesis and characterization of graphitic carbon nitride/titanium dioxide (g-C3N4/TiO2) heterostructures through a fast (1 h) and simple microwave-assisted approach. Different g-C3N4 amounts mixed with TiO2 (15, 30 and 45 wt. %) were investigated for the photocatalytic degradation of a recalcitrant azo dye (methyl orange (MO)) under solar simulating light. X-ray diffraction (XRD) revealed the anatase TiO2 phase for the pure material and all heterostructures produced. Scanning electron microscopy (SEM) showed that by increasing the amount of g-C3N4 in the synthesis, large TiO2 aggregates composed of irregularly shaped particles were disintegrated and resulted in smaller ones, composing a film that covered the g-C3N4 nanosheets. Scanning transmission electron microscopy (STEM) analyses confirmed the existence of an effective interface between a g-C3N4 nanosheet and a TiO2 nanocrystal. X-ray photoelectron spectroscopy (XPS) evidenced no chemical alterations to both g-C3N4 and TiO2 at the heterostructure. The visible-light absorption shift was indicated by the red shift in the absorption onset through the ultraviolet-visible (UV-VIS) absorption spectra. The 30 wt. % of g-C3N4/TiO2 heterostructure showed the best photocatalytic performance, with a MO dye degradation of 85% in 4 h, corresponding to an enhanced efficiency of almost 2 and 10 times greater than that of pure TiO2 and g-C3N4 nanosheets, respectively. Superoxide radical species were found to be the most active radical species in the MO photodegradation process. The creation of a type-II heterostructure is highly suggested due to the negligible participation of hydroxyl radical species in the photodegradation process. The superior photocatalytic activity was attributed to the synergy of g-C3N4 and TiO2 materials.publishersversionpublishe

    Is food insecurity related to health-care use, access and absenteeism?

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    © The Authors 2019. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly citedObjective: Food insecurity (FI) is defined as uncertain access to healthy food in quantity and quality. We hypothesize that FI may be associated with greater health-care use and absenteeism because it may amplify the effect of diseases; also, FI may be associated with reduced health-care access because it reflects economic vulnerability. The present study estimates the association between FI and health-care use and access, and absenteeism. Design: Cross-sectional data collected in 2015-2016. Health-care use was measured as the number of consultations, taking any drug and having been hospitalized in the past year. Health-care access was measured by the suspension of medication and having fewer consultations due to financial constraints. Absenteeism was measured by the weeks of sickness leave. Binary variables were modelled as a function of FI using logistic regressions; continuous variables were modelled as a function of FI using negative binomial and zero-inflated negative binomial regressions. Covariates were included sequentially. Setting: Portugal. Participants: Non-institutionalized adults from the EpiDoc3 cohort (n 5648). Results: FI was significantly associated with health-care use before controlling for socio-economic conditions and quality of life. Moderate/severe FI was positively related to the suspension of medicines (adjusted OR = 4·68; 95 % CI 3·11, 6·82) and to having fewer consultations (adjusted OR = 3·98; 95 % CI 2·42, 6·37). FI and absenteeism were not significantly associated. Conclusions: Our results support the hypothesis that FI reflects precariousness, which hinders access to health care. The greater use of health care among food-insecure people is explained by their worse quality of life and lower socio-economic condition, so that the specific role of poor nutrition is unclear.This study was funded by a NOVASaude unrestricted research grant; and the Public Health Initiatives Programme (PT06), financed by EEA Grants Financial Mechanism 2009–2014info:eu-repo/semantics/publishedVersio

    Floating TiO2-Cork Nano-Photocatalysts for Water Purification Using Sunlight

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    Funding Information: This work was financed by national funds from FCT—Fundação para a Ciência e a Tecnologia, I.P., in the scope of the projects LA/P/0037/2020, UIDP/50025/2020, and UIDB/50025/2020 of the Associate Laboratory Institute of Nanostructures, Nanomodelling, and Nanofabrication—i3N, but also the UI/BD/151292/2021 (Ph.D. research scholarship). The work was also partially funded by the Nanomark collaborative project between INCM (Imprensa Nacional—Casa da Moeda) and CENIMAT/i3N. Acknowledgments also go to the EC project SYNERGY H2020-WIDESPREAD-2020-5, CSA, proposal nº 952169, EMERGE-2020-INFRAIA-2020-1, proposal nº 101008701, and to the European Community’s H2020 program under grant agreement No. 787410 (ERC-2018-AdG DIGISMART). Publisher Copyright: © 2022 by the authors.In the present study, titanium dioxide (TiO2) nano-photocatalysts were synthesized through microwave irradiation. In a typical microwave synthesis, TiO2 nanomaterials were simultaneously produced in powder form and also directly covering cork substrates. The TiO2 nanopowder was analyzed by X-ray diffraction (XRD), Raman spectroscopy and transmission electron microscopy (TEM), revealing that the solvothermal microwave synthesis resulted only in the TiO2 anatase phase. From Fourier-transform infrared spectroscopy (FTIR), cork’s organic species, along with bands of TiO2, were detected. UV–VIS absorption spectrum revealed an absorption extension to the visible region, since a brown powdered TiO2 product was obtained. Very fine nanoparticles were observed displaying a nearly spherical shape that agglomerates in larger particles. These larger particles fully covered the surface of the honeycomb cork cells, originating TiO2 functionalized cork platforms. The TiO2 functionalized substrates were further tested as floating photocatalysts and their photocatalytic activity was assessed from rhodamine B degradation under solar simulating light and natural sunlight. Reusability tests were also performed under natural sunlight. The strategy applied in this research work allowed the production of green and low-cost cork platforms based on TiO2 photoactive materials with the ability to purify polluted water under natural sunlight.publishersversionpublishe
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