938 resultados para continental platform


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It is very difficult to make paleoclimatic correlations between continental and marine areas, but it is possible with biostratigraphic data. Reliable correlations can be made only between broad periods: between 3.5 and 3 Ma, around 2.4 Ma, until 1.6 Ma and after 1.6 Ma. The arid Mediterranean phases led to the disappearance of the European Villafranchian fauna (1.0 Ma).

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This study identifies and describes the major Cenozoíc glyptogenesis and sedimentation episodes in the Minho region (NW Portugal). The fluvial processes of exorheic network were mainly the builders of Cenozoic landscape. This paper presents a chronological sequence of the major fluvial events based on geomorphology and sedimentary characteristics obtained in former studies and new ones. The oldest Cenozoic sedimentation (Placencian) remains on local depressions and was generated by fluvial and fluvio-lacustrine processes. Quaternary glyptogenesis begins probably with a major European cooling (Gunz?). So, the Placencian infilling was eroded and a new episode of sedimentation was accumulated in the same early paleovalley. There were three more cycles of quaternary glyptogenesis and sedimentation. The last glyptogenesis episode records the last glacial period. The post-glacial alluvion contains clasts of granites, schists, feldspats, and other alterable lithologies and minerals; on clay dimensions there are abundant illite and interstratified minerals. This composition differs from the older ones, more siliciclastic and kaolinitic. Other minor erosion episodes were identified, controlled manly by eustasy; evidences of tectonic movements were observed only in rio Minho valley.

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One of the most common characteristics of Portuguese littoral is the existence of a planed surface (the so-called "littoral platform"), situated at different altitudes and bordered from the inland by a straight relief, strongly contrasting with that planed surface. This one is generally covered with several outcrops of the so-called Plio-Pleistocene deposits. Till the eighties this platform has been interpreted as stable staircase of old marine levels, registering in a passive way the eustatic variations. The rigid step bordering it easterly should be a fossil cliff. However, our study has proved that many of these deposits have a continental origin. These continental deposits have fluvial or alluvial fan facies and they are lying above 40 meters. Marine deposits seem to be quite rare and they only occupy a small western area, beneath the altitude of 40 meters and developing into three different marine levels. There is a rigid step between the two kinds of deposits. We think that the clear geometric separation between these deposits together with this rigid step, indicates a tectonic origin. It seems that the sea must have touched only the western part of this surface, when neotectonic movements lowered it down. There are more evidences for neotectonic movements: a) there are faults (mainly inverse faults) affecting the higher deposits of this littoral platform; b) the same marine level seems to appear at different altitudes, developing an irregular pattern with a general trend dipping from the North to the South.

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Sandpit exploitation near Lisbon allowed collecting of many Miocene, non marine fossils. These sands are part of the mostly marine Miocene series in the Lower Tagus basin. The particularly favourable situation led several researchers to deal with marine-continental correlations. Difficulties often concern methodologic aspects. Some poorly based interpretations exerced a lasting influence. A critical approach is presented. Analysis requires data. Methods based upon models often lead to the temptation of fitting data in order to confirm a priori conclusions, or of mixing up data as if of equal statistic value while they have not at all the same weight. Erroneous interpretations' uncritical repetition for many years "upgraded" them into absolute truth. Another point is endemism vs. europeism. Miocene mammals from Lisbon compared well with corresponding French, contemporaneous taxa, while this was apparently not true for Spanish ones. Too much accent had been put on the endemic character of Spanish, or even regional, mammalian faunas. Nationalist bias and sensationalism also weigh, albeit negatively. Meanwhile nearly all the more evident examples as the rhinoceros Hispanotherium are discredited as Iberian endemisms. Taxa may appear as endemic just because they have not yet been found elsewhere. At least for the medium to large-sized mammals, with their huge geographic distribution, faunal differences depend much more on ecology, climate and environmental conditions. Emphasis on differences may also result from researchers that are often in a precarious situation and need very much to achieve short-term, preferably sensational results. Overvalued differences may mask real similarities. Unethic and not scientific behaviour are further enhanced by "nomina nuda" tricks that may simply be a way to circunvent or cheat the Priority Rule. On the other hand, access to communication networks may present as sensational novelties items that are not new at all, misleading the audience. A new class of "science people" arose, created by the media and not by the value of their real achievements. Discussion is presented on sedimentation processes and discontinuities that are often regarded as absolute precision dating tools, as well as on some geochemical and paleomagnetic interpretations. A very good chronologie frame has been obtained for the basin under study on the basis of an impressive set of data, providing a rather detailed and accurate frame for Miocene marine-continental correlations.

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During a recent field work on the southern coast of the island of Santa Maria (Azores) a bulk sample of 37 shells and 25 fragments of Leptaxis vetusta was assembled from Late Pleistocene and Holocene slope deposits outcropping in the area. These specimens are the first of this rare subfossil species to be mentioned since the original descriptions of Arthur Morelet and Henri Drouet (1857). The purposes of our paper are a systematic and biometric description of L. vestuta. For the first time, the original type: locality was localized with accuracy over the southern downslopes of Pico do Facho, between Figueiral and Prainha. The subfossil specimens were collected in slope deposits and detritic fans, overlying a fossiliferous marine deposit situated over the 2-3 m abrasion platform of Praia and Prainha bay. The age and factors associated to the extinction of this species are discussed, including the destruction of the original laurel cover and the colonization by Otala lactea (Muller, 1774), a continental helicid introduced and widespread in Santa Maria.

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With an example taken from a late-Hauterivian series of the Lusitanian Basin (Portugal), we will demonstrate the sedimentary record of orbital pattern variations and, consequently, climate variations in an inner platform environment with patterns and isolation changes, allows us to establish 4 major orders of periodicity related to orbital components:- The large cycles ob bed thickness variation, constituted by 31-32 beds, recording the 400 ky eccentricity cycle component;- The medium cycles, represented by byndles of 8-9 beds, related to the 100 ky eccentricity cycle component; - The small cycles, of 3-5 beds, recording the 41 ky obliquity components;- The very small cycles, of 2 beds, related to the 22 ky and 26 ky precession components. The mean duration of each bed is around 11.8 ky, a number very close to that of the precession hemi-cycle. Climatic control on qualitative production is confirmed by the close relation between the bed thickness variations, the insolation variability and the variation of micritized elements concentrations.

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RESUMO - As alterações climáticas alteraram a incidência e distribuição mundial de zoonoses, ao modificarem o perfil epidemiológico dos seus vectores. A leishmaniose visceral é reemergente na bacia mediterrânica, sendo o seu impacto real subestimado. Em Portugal, é endémica em três regiões, de declaração obrigatória desde 1948 e o reservatório é o canídeo. O aumento da incidência da doença no cão e a escassez de informação epidemiológica tornou pertinente investigar a realidade nacional. A partir das bases de dados das notificações e dos grupos de diagnósticos homogéneos hospitalares, foram identificados todos os casos e, consultados todos os processos clínicos dos doentes com episódios de internamento nos hospitais do continente entre 1999-2009. Ocorreram 730 internamentos para 375 indivíduos na maioria: homens, eurocaucasianos, com em média, 27 anos e, residência em Lisboa e Vale do Tejo. A sintomatologia e comorbilidades dos doentes vão de encontro ao descrito internacionalmente. A doença foi subnotificada, com uma demora média de 19 dias. A letalidade foi de 5%. A taxa de incidência média do continente foi de 0,294/100000 habitantes, sem padrão de sazonalidade. O corredor endémico de Bortman construído apresentou picos com amplitudes de 2-3 anos. O mapeamento dos doentes evidenciou casos em regiões não endémicas acompanhando a distribuição da leishmaniose canina. Seria pertinente que futuras investigações construíssem uma modelação matemática que confirmasse a tendência do corredor endémico (pico em 2011?) para accionar um sistema de alerta nos Serviços de Saúde. Seria também útil a avaliação das condições geoclimáticas das localidades com casos para evidenciar possíveis similitudes no território. -------ABSTRACT - Climate changed the incidence and worldwide distribution of zoonosis while the epidemiological profile of their vectors was changing. Visceral leishmaniasis is reemerging in the Mediterranean basin and its real impact underestimated. In Portugal, it’s endemic in three regions; the notification occurs since 1948 and dog is the reservoir. The increased incidence of the canines’ disease and the scarcity of epidemiological information relevant investigate the national reality. From Notifications and Homogeneous’ Diagnostics Groups system databases, all cases were identified and also analyze all clinical processes of inpatients’ hospitals in 1999- 2009 in Portugal. 730 admissions occurred for 375 patients. In most they were men, Caucasians, with an average of 27 years and residency in Lisboa e Vale do Tejo. The symptoms and comorbilidades patient go against described internationally. The disease was under notified, with an average delay of 19 days. Lethality was 5%. The incidence rate was 0,294/100000 inhabitants, without seasonality. The endemic’s Bortman corridor presents peak amplitudes of 2-3 years. Mapping patient’s residency shows that cases’ distribution is similar to endemic canine leishmaniasis. It would be appropriate a research to build a mathematical modeling up to confirm the trend of corridor endemic (peak in 2011?), to trigger an alert system for health services. It would also be useful to evaluate the geo-climatics conditions of localities with cases to highlight possible similarities in the territory.

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Environmental concerns and the shortage in the fossil fuel reserves have been potentiating the growth and globalization of distributed generation. Another resource that has been increasing its importance is the demand response, which is used to change consumers’ consumption profile, helping to reduce peak demand. Aiming to support small players’ participation in demand response events, the Curtailment Service Provider emerged. This player works as an aggregator for demand response events. The control of small and medium players which act in smart grid and micro grid environments is enhanced with a multi-agent system with artificial intelligence techniques – the MASGriP (Multi-Agent Smart Grid Platform). Using strategic behaviours in each player, this system simulates the profile of real players by using software agents. This paper shows the importance of modeling these behaviours for studying this type of scenarios. A case study with three examples shows the differences between each player and the best behaviour in order to achieve the higher profit in each situation.

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Multi-agent approaches have been widely used to model complex systems of distributed nature with a large amount of interactions between the involved entities. Power systems are a reference case, mainly due to the increasing use of distributed energy sources, largely based on renewable sources, which have potentiated huge changes in the power systems’ sector. Dealing with such a large scale integration of intermittent generation sources led to the emergence of several new players, as well as the development of new paradigms, such as the microgrid concept, and the evolution of demand response programs, which potentiate the active participation of consumers. This paper presents a multi-agent based simulation platform which models a microgrid environment, considering several different types of simulated players. These players interact with real physical installations, creating a realistic simulation environment with results that can be observed directly in the reality. A case study is presented considering players’ responses to a demand response event, resulting in an intelligent increase of consumption in order to face the wind generation surplus.

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In a highly competitive market companies know that having quality products or provide good services is not enough to keep customers "faithful". Currently, quality of products/services, location and price are fundamental aspects customers expect to get on every purchase, so they look for ways to distinguish companies. This can happen either in a strictly materialistic way or by evaluation of intangible metrics such as having his opinion appreciated or being part of a selected group of "premium" customers. Therefore, companies must find ways to value and reward its customers in order to keep them "faithful" to their products or services. Loyalty systems are one means to achieve this goal, however, due to its nature and how they are implemented, often companies end up having low acceptance, without achieving intended objectives. In an era of technological revolution, where global average adoption of smartphones and tablets is 74% and 40% [Our Mobile Planet, 2014], the opportunity to reinvent loyalty systems reappears. Throughout this thesis a new tool, relying on the latest technologies and aiming to fulfill this market opportunity, will be presented. The main idea is to use ancient loyalty concepts, such as stamps or pointscards, and transforms them into digital cards, to be used in digital wallets, introducing an innovative technology component based on Apple's Passbook technology. The main goal is to create a platform for managing the card’s life cycle, allowing anyone to create, edit, distribute and analyze the data, and also create a new communication channel with customers, improving the customer-­‐supplier relationship and enhancing the mobile-­‐marketing.

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Os aproveitamentos geotérmicos têm vindo a aumentar significativamente em todo o mundo, sendo os Estados Unidos da América, o maior produtor desta energia proveniente do interior da Terra, com cerca de 3.187 MW de capacidade instalada. Portugal tem capacidade instalada total de 29 MW, no entanto no que se refere ao aproveitamento de “alta entalpia”, isto é, o aproveitamento geotérmico para produção elétrica, apenas se encontra no arquipélago dos Açores, na ilha de S. Miguel, onde estão instaladas e em funcionamento duas centrais geotérmicas com a potência total de 23 MW, com produção de energia de 185 GWh. Em Portugal Continental, não se consegue produzir energia elétrica devido às temperaturas existentes, restringindo esta utilização apenas ao aproveitamento de baixa entalpia (máximo de 76 ºC). Este aproveitamento normalmente é feito em cascata, segundo, predominando o aquecimento de águas sanitárias, climatização, e para termas, usando águas termominerais. Para a exploração deste recurso renovável, é necessário conhecer a hidrogeologia do país, e relacioná-la com a fracturação, e acidentes tectónicos. Portugal Continental, está divido em quatros partes distintas a nível hidrogeológico, o Maciço Antigo, a Orla Ocidental, a Bacia Tejo-Sado e a Orla Meridional. Qualquer aproveitamento geotérmico em Portugal terá de atender a estas características, potenciando também, novas explorações geotérmicas orientadas para as pessoas, respeitando os valores sociais, culturais e ambientais. Neste contexto, existem alguns complexos geotérmicos em funcionamento, outros abandonados, e muitos outros em estudo para uma breve aplicação. Um exemplo de sucesso no aproveitamento do calor geotérmico, é o complexo de Chaves, que foi evoluindo desde 1985, até aos dias de hoje, continuando em exploração e em expansão para um melhor servir da população local. A existência de dois furos, e brevemente dum terceiro, servem para o abastecimento duma piscina, dum hotel, das termas, e da balneoterapia. Devido à riqueza a nível das temperaturas, dos caudais, e ao nível das necessidades energéticas existentes, este complexo apresenta um tempo de retorno de investimento de cerca de 7 anos, o que é geralmente considerado para investimentos para fins públicos, como é o caso. No âmbito das investigações agora realizadas, foi constatado que estes projetos suportam a cobertura de alguma incerteza hidrogeológica, dada a importante procura existente.

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ISCAP’s Information Systems Department is composed of about twenty teachers who have, for several years, been using an e-learning environment (Moodle) combined with traditional assessment. A new e-assessment strategy was implemented recently in order to evaluate a practical topic, the use of spreadsheets to solve management problems. This topic is common to several courses of different undergraduate degree programs. Being e-assessment an outstanding task regarding theoretical topics, it becomes even more challenging when the topics under evaluation are practical. In order to understand the implications of this new type of assessment from the viewpoint of the students, questionnaires and interviews were undertaken. In this paper the analysis of the questionnaires are presented and discussed.

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Near real time media content personalisation is nowadays a major challenge involving media content sources, distributors and viewers. This paper describes an approach to seamless recommendation, negotiation and transaction of personalised media content. It adopts an integrated view of the problem by proposing, on the business-to-business (B2B) side, a brokerage platform to negotiate the media items on behalf of the media content distributors and sources, providing viewers, on the business-to-consumer (B2C) side, with a personalised electronic programme guide (EPG) containing the set of recommended items after negotiation. In this setup, when a viewer connects, the distributor looks up and invites sources to negotiate the contents of the viewer personal EPG. The proposed multi-agent brokerage platform is structured in four layers, modelling the registration, service agreement, partner lookup, invitation as well as item recommendation, negotiation and transaction stages of the B2B processes. The recommendation service is a rule-based switch hybrid filter, including six collaborative and two content-based filters. The rule-based system selects, at runtime, the filter(s) to apply as well as the final set of recommendations to present. The filter selection is based on the data available, ranging from the history of items watched to the ratings and/or tags assigned to the items by the viewer. Additionally, this module implements (i) a novel item stereotype to represent newly arrived items, (ii) a standard user stereotype for new users, (iii) a novel passive user tag cloud stereotype for socially passive users, and (iv) a new content-based filter named the collinearity and proximity similarity (CPS). At the end of the paper, we present off-line results and a case study describing how the recommendation service works. The proposed system provides, to our knowledge, an excellent holistic solution to the problem of recommending multimedia contents.

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Dissertação para obtenção do Grau de Mestre em Engenharia do Ambiente, perfil de Engenharia Ecológica