5,619 research outputs found

    Climate variability impacts on coastal dune slack ecohydrology

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    The hydrological regime of freshwater systems plays a crucial role in shaping the dynamics of the different biological communities that inhabit them. Climate change is expected to cause major alterations in the hydrological regime of dune slacks by producing shifts in temperature, precipitation and evapotranspiration. Across seasons, we explore the controls on common water fleas (Cladocera) and aquatic plant communities relative to water level regime, water chemistry, weather and geomorphological setting, in a slack of the Sheskinmore dune system, Co. Donegal, northwest Ireland. Cladoceran abundance and diversity peak in summer, but also vary inter-annually, and drivers for this and hydrological variability are discussed. Vegetation is likewise affected by hydrology in a spatial sense, where distribution follows wet/dry patches of water. Water chemistry is more variable within the same season than across different years, particularly related to the drying out of the slack. Rainfall through 2016-2017 was lower than average and evapotranspiration showed higher values than average for the same time period. The influence on the slack of this decreased precipitation extended across successive seasons. The water table is the most important driver of slack ecology, with incidence on biological communities expressed by the increased variability inter-annually, as opposed to seasonal variation

    Dactylorhiza elata, Stately Dactylorhiza

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    Mediterranean regional assessment: Near Threatened (NT) The species is found from southwestern Europe and northwestern Africa. In two countries within the Mediterranean distribution (France and Portugal) populations or habitat of this species have declined by more than 30% over three generations. In another two countries (Algeria and Morocco) a similar decline is suspected but cannot yet be confirmed, and in Spain populations appear to be relatively abundant however there is no information on population trends. Elsewhere the species is known only from singlesites in Sardinia and Tunisia. whilst the extent of occurrence is very large, the area of occupancy (AOO) is possibly restricted however distribution data are inadequate to confirm the AOO. Therefore whilst the rate of decline cannot be measured throughout the range of the species, the Mediterranean population decline is confirmed, it is ongoing and is not reversible, consequently this species is close to classification as Vulnerable (A2c and A4c). Further to this, if monitoring data become available to provide an indication of population trends in Spain and these show that it is in decline then it is clear that the species should be considered threatened at both the Mediterranean and global scales. This species is therefore classed as Near Threatened, approaching Vulnerable (A2c+4c)

    Issues’21 - Issues in Education

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    In the scope of the INW21, an international scientific joint event organized by Politécnico do Porto – Escola Superior de Educação (International Relations Office) and inED – Centre for Research and Innovation in Education, teachers, researchers and staff working in the field of Education joined together to share, discuss, reflect on and develop their ideas on topics related to Networking in Education. This meeting offered good opportunities for intercultural exchange and both personal and academic development. Therefore, professionals who attended the INW21 Conference / International Week had the chance to get in touch with high quality presentations which portray the rich research projects that we, educational practitioners, have been undertaking. Therefore, in order to make record of these presentations, a call for chapters has been promoted. In this way, issuEs 21 – Issues in Education, an e-Book, has been born.This publication is funded by National Funds through the FCT - Fundação para a Ciência e a Tecnologia, I.P., under the scope of the project UIDB/ 05198/2020 (Centre for Research and Innovation in Education, inED).info:eu-repo/semantics/publishedVersio

    Equity Research - Lowe’s Companies Inc

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    Mestrado em FinançasPara esta Equity Research escolhemos a Lowe's Companies Inc por ser uma das maiores empresas de retalho de produtos para habitação no mundo assim como por estar associada a várias iniciativas solidárias nos países onde opera. Caracterizamos o setor de produtos para habitação como tendo vários produtores, produtos semelhantes, mas que nos Estados Unidos da América é dominado por 2 empresas: Lowe's e Home Depot. Na avaliação da Lowe's a data de referência é 30/09/2020 e recorremos a vários métodos de atualização, de forma a obter uma recomendação o mais correta possível. No método dos Fluxos de caixa, através dos fluxos de caixa da empresa, obtivemos um preço de ação de 142,querepresentaumaperdaquandocomparadocomoprec\codadataderefere^nciade14.2, que representa uma perda quando comparado com o preço da data de referência de 14.2%, sendo este o nosso principal método de avaliação. Com a avaliação relativa, através da utilização de EV/EBITDA e P/E da Home Depot, assim como com o método de pagamento total obtivemos preços de ação menores que a ação na data de referência, 166. Os principais riscos que identificamos associados à operação da Lowe's são a reputação da marca, dificuldades em enfrentar futuros desafios, volatilidade na moeda estrangeira e decisões políticas. Tendo em consideração esta perda assim como o risco médio de investimento nesta empresa, a nossa recomendação é para os investidores venderem.In this Equity Research, we chose Lowe's Companies Inc because it is one of biggest Home Improvement Companies in the world and with positive impact in its country as it is associated with many solidarity events. We characterized Home Improvement retail as a market with many producers, similar products and dominated in USA by 2 companies: Lowe's and Home Depot. To valuate Lowe's, we took as reference date 30/09/2020 and computed some different valuation methods in order to get the best valuation possible. In Discounted Cash Flow through Free Cash Flow to Firm where we get a price of 142pershare,meaningadownsidepotentialwhencomparedwithreferencedateof14.2 per share, meaning a downside potential when compared with reference date of 14.2% being this our main valuation method. With relative valuation, using EV/EBITDA and P/E of Home Depot as well as with total payout method we get a lower share price than what we have in our reference date, 166. Main risks associated with Lowe's operations that we identified are brand reputation, difficulties in adapting to new challenges that may occur, volatility in foreign currencies and political decisions. Taking this downside potential in consideration as a medium risk associated with this company, we recommend a sell position to investors.info:eu-repo/semantics/publishedVersio

    Habitat Variation in Vernal Pool Ecosystems on Both Sides of the Strait of Gibraltar

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    We studied vernal pool (VP) ecosystems along a latitudinal gradient crossing the Strait of Gibraltar in order to determine its role in the distribution of VP plant communities. We analyzed flora, vegetation, physical–chemical water parameters, and climatic data from two vernal pool areas on both the European (Iberian) and African (Moroccan) sides of the Strait. Despite the minor distance between both territories, the pools clearly differed in species composition and ecology. However, they showed a similar vegetation zonation in growth forms, including isoetid, batrachiid, and helophytic vegetation. The distribution of the plant communities was related to nutrient load, temperature, and precipitation. Water nitrate concentration was higher in Morocco, where VPs are characterized by Isoetes velata subsp. adspersa and Ranunculus saniculifolius communities. Iberian VPs had lower water nitrate content, and were characterized by Isoetes velata subsp. velata and Ranunculus peltatus communities. We think this nutrient difference is likely to be caused by the different land management regime on each side of the Strait, with more intensive agriculture in Morocco. Long-term (historical) and present-day (ecological) processes have been proposed to account for the habitat variation in vernal pool ecosystems on both sides of the Strait of Gibraltar

    Desenvolvimento e ensaio de um secador convectivo para alimentos

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    Dissertação de Mestrado em Qualidade e Tecnologia AlimentarA presente dissertação versa sobre a concepção e exploração de um secador convectivo de produtos alimentares. Partindo-se do invólucro exterior (secador), neste foi instalado o equipamento para promover o aquecimento e escoamento do ar interior. Para monitorizar e controlar o processo de secagem, procedeu-se à instrumentação da instalação para monitorização/controlo e registo de cada uma das variáveis, nomeadamente: temperatura e humidade do ar, assim como a pesagem contínua dos produtos durante a secagem. Com o objectivo de explorar o comportamento do secador, realizaram-se ensaios preliminares, em que se comparou a eficiência de secagem obtida com o secador desenvolvido e uma estufa. Nos ensaios finais comparam-se os resultados para duas variedades de maçã, a 'Golden Delicious' e a 'Granny Smith', ambas secadas no secador desenvolvido. Para efeitos de comparação realizaram-se várias análises, que envolveram a determinação da humidade, acidez, sólidos solúveis totais, a cor e a textura das respectivas maçãs, em fresco e depois de secadas, num intervalo de temperaturas de 30ºC e 60ºC. Além disso estudou-se também a cinética de secagem em termos de modelos de camada fina, e também por meio da equação de difusão de Fick. Assim, avaliaram-se algumas propriedades de transferência de massa, como a humidade de difusividade efectiva e o coeficiente de transferência convectiva de massa. Os resultados mostram que para ambas as variedades de maçãs estudadas, a secagem reduz a acidez e o teor em açúcares. No que respeita à cor, esta foi significativamente afetada pela secagem, resultando em elevados valores da diferença de cor total, entre 19.43 e 25,04. Quanto à textura, verificou-se que com a secagem as maçãs tornam-se menos duras e menos coesas. No que respeitou à cinética de secagem, os dados cinéticos foram tratados e ajustados de acordo com diferentes modelos de camada fina que foram: 'Page', 'Henderson' e 'Pabis', 'Logarítmico' e 'Vega-Lemus'. Dos modelos testados foi possível verificar que o modelo 'Vega-Lumus' foi o pior para descrever a cinética de secagem,sendo o de 'Page' o que mostrou melhor adaptação/comportamento. Além disso, verificou-se que a difusidade de massa aumenta com a temperatura, seguindo a função do tipo 'Arrhenius' para as variedades 'Golden Delicious' e 'Granny Smith'.ABSTRACT: This dissertacion examines the design and operation of a food convective dryer. Starting from the outer casing (dryer), all the equipment has been installed to promote the heating and air flow inside. To monitor and control the drying process, all the instrumentation for monitoring/control and registration of each variable was installed, in particular, regardind the variables such as temperature and humidity, as well as the continous weighing of the product during drying. In order to explore the behaviour of the dryer, preliminary tests were carried out, which compared the efficiency obtained by drying in the developed drier and in an oven dryer. In the definitive tests, two varieties of apples, 'Golden Delicious' and 'Granny Smith', were both dried in the developed drier and the results were compared. For this several tests were carried out, which involved the determination of humidity, acidity, total soluble solids, colour and texture of the respective apples, either in fresh and after dried at temperatures in the range of 30ºC to 60ºC. In addittion it was also studied the drying kinetics in terms of thin layer models, and also by Fick's diffusion equation. Thus, some mass tranfer properties were evaluated, such as moisture effective diffusivity and the coefficient of convective mass transfer.The results show that both varieties of apple at study, drying reduces the acidity and sugar content. As regards colour, this was significantly affected by drying, resulting in high values of total colour difference between 19.43 and 25.04. As to texture, it was found that drying turned the apples softer and less cohesive. With respect to drying kinetics, the experimental data were adjusted according to different thin layer models: 'Page', 'Henderson' and 'Pabis', 'logarithmic' and 'Vega-Lemus'. From the models tested, it was able to verify that the model Vega-Lemus was the worst to describe the kinetics of drying and the 'Page' showed the best fit/performance. Furthermore, it was found that the mass diffusivity increases with temperature, following an 'Arrhenius' function for varieties 'Golden Delicious' and 'Granny Smith'

    Temperature and Stress Influence in the Description of Time-Dependent Materials

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    A new creep compliance equation has been developed and validated, yielding a fully coupled time-temperature-stress formulation, with long-term predictive capability. Stress-induced changes in intrinsic time scale were investigated by non-linear creep tests on an ultra-high molecular weight polyethylene (UHMW-PE), at three temperatures. The creep compliance vs. time curves at five different stress levels were determined and shifted along the logarithmic time axis to get an attempted master compliance curve at a given reference stress level, according to the concept of time-stress equivalence. Experimental data for the polyethylene were obtained and analysed to identify the extent to which time-stress superposition relationships may be valid, and it is shown that they are only approximations, limited to narrow ranges of the experimental variables, in contrast with the proposed model that more accurately fits the experimental behaviour

    Structuring a knowledge-based maritime cluster: contributions of network analysis in a tourism region

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    The notion of maritime cluster encompasses a diversity of activities from fi sheries, aquaculture, transports to coastal tourism or even science-based activities. This article debates the possibilities to consolidate the maritime cluster as one of the driving forces of the Algarve, a Portuguese region internationally recognized by tourism. This cluster did not emerge spontaneously and several policy initiatives to promote its formalization were being developed. The regional actors are not sure about the organizations that can be mediators in the cluster. Using social network analysis the maritime cluster is mapped, identifying central actors and possible structural holes. Policy implications are underlined.info:eu-repo/semantics/publishedVersio
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