924 resultados para Vila Velha do Cassiporé - AP


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As unidades estratigráficas que resultaram da evolução do rio Tejo em Portugal, aqui analisadas em pormenor entre Vila Velha de Ródão e Chamusca, possuem distintas características sedimentares e indústrias líticas: uma unidade culminante do enchimento sedimentar (o ancestral Tejo, antes do início da etapa de incisão fluvial) - SLD13 (+142 a 262 m acima do leito actual; com provável idade 3,6 a 1,8 Ma), sem indústrias identificadas; terraço T1 (+76 a 180 m; ca. 1000? a 900 ka), sem indústrias; terraço T2 (+57 a 150 m; idade estimada em ca. 600 ka), sem indústrias; terraço T3 (+36 a 113 m; ca. 460 a 360? ka), sem indústrias; terraço T4 (+26 a 55 m; ca. 335 a 155 ka), Paleolítico Inferior (Acheulense) em níveis da base e intermédios mas Paleolítico Médio inicial em níveis do topo; terraço T5 (+5 a 34 m; 135 a 73 ka), Paleolítico Médio (com talhe Mustierense, Levallois); terraço T6 (+3 a 14 m; 62 a 32 ka), Paleolítico Médio final (Mustierense final); Areias da Carregueira (areias eólicas) e coluviões (+3 a ca. 100 m; 32 a 12 ka), Paleolítico Superior a Epipaleolítico; enchimento da planície aluvial (+0 a 8 m; ca. 12 ka a actual), Mesolítico e indústrias mais recentes. As diferenças na elevação (a.r.b.) das escadarias de terraços resultam de soerguimento diferencial, devido a falhas ativas. Numa dada escadaria datada, a projeção da elevação da superfície de cada terraço (a.r.b.) versus a sua idade permitiu estimar a idade do topo do terraço T2 (ca. 600 ka) e a provável idade do início da etapa de incisão (ca. 1,8 Ma). Obteve-se a duração da fase de agradação dos terraços baixos e médios: T6 – 30 ka; T5 – 62 ka; T4 – ca. 180 ka; T3 – ca. 100? ka. Conclui-se que durante o Plistocénico médio e final, as fases de incisão e alargamento do vale foram curtas (ca. 11-25 ka) e ocorreram durante períodos de nível do mar muito baixo, alternando com mais longas fases de inundação e agradação do vale durante níveis do mar mais altos. Estas oscilações eustáticas de causa climática estão sobrepostas a um contexto de soerguimento de longo termo, controlando o desenvolvimento das escadarias. Calculou-se que para os últimos ca. 155 ka as taxas de incisão de curto-termo apresentam valores (0,09 a 0,41 m/ka), aproximadamente, duplos dos calculados para o intervalo ca. 155 a 900 ka (0,04 a 0,28 m/ka). Este aumento na taxa de incisão deve estar relacionado com um aumento na taxa de soerguimento por intensificação da compressão devido à convergência entre as placas Africana e Eurasiática. Abstract: The terrace staircases of the Lower Tagus River (Ródão to Chamusca) – characterization and interpretation of the sedimentary, tectonic, climatic and Palaeolithic data The stratigraphic units that record the evolution of the Tagus River in Portugal (study area between Vila Velha de Ródão and Chamusca villages) have different sedimentary characteristics and lithic industries: a culminant sedimentary unit (the ancestral Tagus, before the drainage network entrenchment) – SLD13 (+142 to 262 m above river bed – a.r.b.; with probable age 3.6 to 1.8 Ma), without artefacts; T1 terrace (+76 to 180 m; ca. 1000? to 900 ka), without artefacts; T2 terrace (+57 to 150 m; top deposits with a probable age ca. 600 ka), without artefacts; T3 terrace (+36 to 113 m; ca. 460 to 360? ka), without artefacts; T4 terrace (+26 to 55 m; ca. 335 a 155 ka), Lower Paleolithic (Acheulian) at basal and middle levels but early Middle Paleolithic at top levels; T5 terrace (+5 to 34 m; 135 to 73 ka), Middle Paleolithic (Mousterian; Levallois technique); T6 terrace (+3 to 14 m; 62 to 32 ka), late Middle Paleolithic (late Mousterian); Carregueira Sands (aeolian sands) and colluvium (+3 a ca. 100 m; 32 to 12 ka), Upper Paleolithic to Epipaleolithic; alluvial plain (+0 to 8 m; ca. 12 ka to present), Mesolithic and more recent industries. The differences in elevation (a.r.b.) of the several terrace staircases results from differential uplift due to active faults. The age interval for each aggradation phase of T3 to T6 terraces was obtained: T3 – ca. 100? ka; T4 – ca. 180 ka; T5 – 62 ka; T6 – 30 ka. The intervals of river down-cutting and widening of the valley floor were short (ca. 11-25 ka) and coincided with periods of very low sea-level. The plotting of the elevation (a.r.b.) versus the age of each terrace surface allows to estimate the age of the T2 terrace (ca. 600 ka) and the probable age of the beginning of the incision stage (ca. 1.8 Ma). So, the high amplitude sea-level changes that characterized the Middle and Late Pleistocene strongly determined the episodic down-cutting phases of the river during the low stands sea levels that alternated with the flooding and aggradation phases of the incised valley during highstand sea levels. These climate related eustatic oscillations are superimposed onto a long term uplift pattern, controlling the river terrace staircase development. During the last ca. 155 ka, the short-term incision rates (0.09 a 0.41 m/ka) were twice the values determined for the interval 155 to 900 ka (0.04 to 0.28 m/ka). This increase in incision rate should be related with an increase in uplift rate resulting from an intensification of compression due to the convergence between African - Eurasian plates.

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NEW DATA ON THE CHRONOLOGY OF THE VALE DO FORNO SEDIMENTARY SEQUENCE (LOWER TAGUS RIVER TERRACE STAIRCASE) AND ITS RELEVANCE AS FLUVIAL ARCHIVE OF THE MIDDLE PLEISTOCENE IN WESTERN IBERIA Pedro P. Cunha 1, António A. Martins 2, Jan-Pieter Buylaert 3,4, Andrew S. Murray 4, Luis Raposo 5, Paolo Mozzi 6, Martin Stokes 7 1 MARE - Marine and Environmental Sciences Centre, Department of Earth Sciences, University of Coimbra, Portugal: pcunha@dct.uc.pt 2 MARE - Marine and Environmental Sciences Centre, Dep. Geociências, University of Évora, Portugal; aam@uevora.pt 3 Centre for Nuclear Technologies, Technical University of Denmark, Risø Campus, Denmark; jabu@dtu.dk 4 Nordic Laboratory for Luminescence Dating, Aarhus University, Risø DTU, Denmark; anmu@dtu.dk 5 Museu Nacional de Arqueologia, Lisboa, Portugal; 3raposos@sapo.pt 6 Department of Geosciences, University of Padova, Italy; paolo.mozzi@unipd.it 7 School of Geography, Earth and Environmental Sciences, University of Plymouth, UK; m.stokes@plymouth.ac.uk The stratigraphic units that record the evolution of the Tagus River in Portugal (study area between Vila Velha de Ródão and Porto Alto villages; Fig. 1) have different sedimentary characteristics and lithic industries (Cunha et al., 2012): - a culminant sedimentary unit (the ancestral Tagus, before the drainage network entrenchment) – SLD13 (+142 to 262 m above river bed – a.r.b.; with probable age ca. 3,6 to 1,8 Ma), without artefacts; - T1 terrace (+84 to 180 m; ca. 1000? to 900 ka), without artefacts; - T2 terrace (+57 to 150 m; top deposits with a probable age ca. 600 ka), without artefacts; - T3 terrace (+43 to 113 m; ca. 460 to 360? ka), without artefacts; - T4 terrace (+26 to 55 m; ca. 335 a 155 ka), Lower Paleolithic (Acheulian) at basal and middle levels but early Middle Paleolithic at top levels; - T5 terrace (+5 to 34 m; 135 to 73 ka), Middle Paleolithic (Mousterian; Levallois technique); - T6 terrace (+3 to 14 m; 62 to 32 ka), late Middle Paleolithic (late Mousterian); - Carregueira Sands (aeolian sands) and colluvium (+3 a ca. 100 m; 32 to 12 ka), Upper Paleolithic to Epipaleolithic; - alluvial plain (+0 to 8 m; ca. 12 ka to present), Mesolithic and more recent industries. The differences in elevation (a.r.b.) of the several terrace staircases results from differential uplift due to active faults. Longitudinal correlation with the terrace levels indicates that a graded profile ca. 200 km long was achieved during terrace formation periods and a strong control by sea base level was determinant for terrace formation. The Neogene sedimentary units constituted the main source of sediments for the fluvial terraces (Fig. 2). Geomorphological mapping, coupled with lithostratigraphy, sedimentology and luminescence dating (quartz-OSL and K-feldspar post-IRIR290) were used in this study focused on the T4 terrace, which comprises a Lower Gravels (LG) unit and an Upper Sand (US) unit. The thick, coarse and dominantly massive gravels of the LG unit indicate deposition by a coarse bed-load braided river, with strong sediment supply, high gradient and fluvial competence, during conditions of rapidly rising sea level. Luminescence dating only provided minimum ages but it is probable that the LG unit corresponds to the earlier part of the MIS9 (ca. 335 to 325 ka), immediately postdating the incision promoted by the very low sea level (reaching ca. -140 m) during MIS10 (362 to 337 ka), a period of relatively cold climate conditions with weak vegetation cover on slopes and low sea level. Fig. 1. Main Portuguese reaches in which the Tagus River can be divided (Lower Tagus Basin): I – from the Spanish border to Arneiro (a general E–W trend, mainly consisting of polygonal segments); II – from Arneiro to Gavião (NE–SW); III – from Gavião to Arripiado (E–W); IV – from Arripiado to Vila Franca de Xira (NNE-SSW); V – from Vila Franca de Xira to the Atlantic shoreline. The faults considered to be the limit of the referred fluvial sectors are: F1 – Ponsul-Arneiro fault (WSW-ENE); F2 – Gavião fault (NW-SE); F3 – Ortiga fault (NW-SE); F4 – Vila Nova da Barquinha fault (W-E); F5 – Arripiado-Chamusca fault (NNE-SSW). 1 – estuary; 2 – terraces; 3 – faults; 4 – Tagus main channel. The main Iberian drainage basins are also represented (inset). The lower and middle parts of the US unit, comprising an alternation of clayish silts with paleosols and minor sands to the east (flood-plain deposits) and sand deposits to the west (channel belt), have a probable age of ca. 325 to 200 ka. This points to formation during MIS9 to MIS7, under conditions of high to medium sea levels and warm to mild conditions. The upper part of the US unit, dominated by sand facies and with OSL ages of ca. 200 to 154 ka, correlates with the early part of the MIS6. During this period, progradation resulted from climate deterioration and relative depletion of vegetation that promoted enhanced sediment production in the catchment, coupled with initiation of sea-level lowering that increased the longitudinal slope. The Vale do Forno and Vale da Atela archaeological sites (Alpiarça, central Portugal) document the earliest human occupation in the Lower Tagus River, well established in geomorphological and environmental terms, within the Middle Pleistocene. The Lower Palaeolithic sites were found on the T4 terrace (+26 m, a.r.b.). The oldest artefacts previously found in the LG unit, display crude bifacial forms that can be attributed to the Acheulian, with a probable age of ca. 335 to 325 ka. The T4 US unit has archaeological sites stratigraphically documenting successive phases of an evolved Acheulian, that probably date ca. 325 to 300 ka. Notably, these Lower Palaeolithic artisans were able to produce tools with different sophistication levels, simply by applying different strategies: more elaborated reduction sequences in case of bifaces and simple reduction sequences to obtain cleavers. Fig. 2. . Simplified geologic map of the Lower Tagus Cenozoic basin, adapted from the Carta Geológica de Portugal, 1/500000, 1992). The study area (comprising the Vale do Forno and Vale de Atela sites) is located on the more upstream sector of the Lower Tagus River reach IV, between Arripiado and Chamusca villages. 1 – alluvium (Holocene); 2 – terraces (Pleistocene); 3 – sands, silts and gravels (Paleogene to Pliocene); 4 – Sintra Massif (Cretaceous); 5 – limestones, marls, silts and sandstones (Mesozoic); 6 – quartzites (Ordovician); 7 – basement (Proterozoic to Palaeozoic); 8 – main fault. The main Portuguese reaches of the Tagus River are identified (I to V). The VF3 site (Milharós), containing a Final Acheulian industry, with fine and elaborated bifaces) found in a stratigraphic level located between the T4 terrace deposits and a colluvium associated with Late Pleistocene aeolian sands (32 to 12 ka), has an age younger than ca. 154 ka but much older than 32 ka. In the study area, the sedimentary units of the T4 terrace seem to record the river response to sea-level changes and climatically-driven fluctuations in sediment supply. REFERENCES Cunha P. P., Almeida N. A. C., Aubry T., Martins A. A., Murray A. S., Buylaert J.-P., Sohbati R., Raposo L., Rocha L., 2012, Records of human occupation from Pleistocene river terrace and aeolian sediments in the Arneiro depression (Lower Tejo River, central eastern Portugal). Geomorphology, vol. 165-166, pp. 78-90.

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O pirarucu é um peixe nativo da bacia Amazônica cuja criação vem sendo estudada em algumas partes do Brasil. O objetivo desse trabalho foi testar o sal de cozinha como mitigador de estresse durante o transporte de juvenis de pirarucu (1 kg). Para isso, os peixes foram transportados em dois diferentes sistemas: caixas sem adição de oxigênio (transporte aberto) e sacos plásticos com injeção de oxigênio e lacrado (transporte fechado).

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O objetivo deste trabalho foi avaliar o efeito do sal (NaCl) sobre as respostas fisiológicas e controle de helmintos monogenóides em tambaqui (Colossoma macropomum). Para isso, juvenis de tambaqui (42,38 ± 0,47 g; 13,90 ± 0,06 cm) foram transferidos para tanques de 350L e aclimatados por um período de 24 horas. Os ensaios foram conduzidos utilizando as concentrações de 0, 2, 4, 6 e 8 g de sal comum L-1 de água, nos tempos de exposição de 30, 60 e 120 minutos, com três repetições por tratamento. A tolerância dos tambaquis ao sal e a eficácia deste sobre os helmintos monogenóides foi avaliada mediante análise dos indicadores fisiológicos (glicose, cloretos, sódio e potássio plasmático) e parasitológicos (número total de parasitas e prevalência). Tambaquis expostos a 4 g NaCl L-1 por 120 minutos, 6 e 8 g NaCl L-1 por 60 e 120 minutos apresentaram maior elevação da glicose plasmática e na concentração de 8 g NaCl L-1 por 120 minutos maiores níveis de cloreto plasmático. A prevalência de monogenóides nas brânquias foi de 100% e todas as concentrações de sal avaliadas neste estudo não foram eficazes na redução dos helmintos monogenóides em tambaqui.

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Tese apresentada para cumprimento dos requisitos necessários à obtenção do grau de Doutor em Estudos Portugueses, especialidade de Estudos de Literatura

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It is important that we understand the factors and conditions that shape driver behaviour – those conditions within the road transport system that contribute to driver error and the situations where driver non-compliance to road regulations is likely. This report presents the findings derived from a program of research investigating the nature of errors made by drivers, involving a literature review and an on-road study. The review indicates that, despite significant investigation, the role of different error types in road traffic crashes remains unclear, as does the role of the wider road transport system failures in driver error causation.

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Seat belts are one of the most effective passive safety features in vehicles and there is a host of research literature attesting to the effectiveness of seat belts in protecting against death and injury. Even when use rates are high the potential gains in trauma reduction from further improvements in wearing rates are substantial. However, those currently most resistant to restraint use have also proven most difficult to target using conventional countermeasures. It is necessary to address the issues of non-wearing in order to achieve further gains in seat belt wearing. This study provide evidence-based recommendations for the way forward to tackle the problems of adult restraint non-use in light passenger vehicles in the short, medium and longer term in Australia. While there are substantial issues to be addressed for these groups, these are outside the scope of this study.

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Jean-Jacques Rousseau’s Émile, ou de I’Education (Émile, or on Education) has been described by Rousseau scholars in latter twentieth century English-language philosophy as an educational classic. In 1995 Robert Wokler argued that together with Montesquieu, Hume, Smith, and Kant among his contemporaries, Rousseau had exerted the most profound influence on modern European intellectual history, “perhaps even surpassing anyone else of his day." For Wokler Émile is “the most significant work on education after Plato’s Republic.” Earlier in 1977, Allan Bloom questioned why Émile had not been the subject of analysis in philosophy relative to the rest of Rousseau‘s work, for “Émile is truly a great book, one that lays out for the first time and with the greatest clarity and vitality the modern way of posing the problems of psychology.” Bloom also saw Émile as “one of those rare total or synoptic books... a book comparable to Plato’s Republic, which it is meant to rival or supersede” and argued that Rousseau himself was at the source of a new tradition: “Whatever else Rousseau may have accomplished, he presented alternatives available to man more comprehensively and profoundly and articulated them in the form which has dominated discussion since his time." Even Peter Gay’s earlier commentary on John Locke and education in 1964 could not escape this central positioning of the text. The significance of Locke’s Some Thoughts on Education is weighed in relation to its impact on Rousseau‘s Émile. For Gay, the latter is “probably the most influential revolutionary tract on education that we have.”

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Thermal decomposition and combustion of lithium perchlorate ammine:ammonium perchlorate (LPA:AP) and magnesium perchlorate ammine:ammonium perchlorate (MPA:AP) pellets have been studied using DTA, TG, and strand burner techniques. The DTA results of the ammine:AP pellets show that the addition of ammines lowers the ignition temperature of AP. However, isothermal TG of the ammine:AP pellets show that in the case of LPA:AP pellets the extent of decomposition increases with the increase in the concentration of LPA; whereas in the case of MPA:AP pellets the extent of decomposition decreases with the increase in the concentration of MPA. Similarly, LPA:AP pellets show higher burning rates compared to AP pellets. On the other hand, MPA:AP pellets show lower burning rates compared to AP pellets. Increasing the concentration of MPA in MPA:AP pellets completely suppresses the combustion. These results are explained on the basis of the thermal characteristics of the additives and their decomposition products.

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THE addition of catalysts normally serves the purpose of imparting a desired burning rate change in a composite propellant. These may either retard or enhance the burning rate. Some often quoted catalysts are oxides, chromites and chromates of metals. A lot of work has been done on rinding the effect of the addition of some of these catalysts on the burning rate; however, none seems to have appeared on the influence of lithium fluoride (LiF). Only qualitative reduction in the burning rate of composite propellants with the addition of LiF was reported by Williams et al.1 Dickinson and Jackson2 reported a slight decrease in the specific impulse of composite propellant with the addition of LiF; however, they made no mention of the effect of its addition on the burning rate. We have studied the effect of the addition of varying amounts of LiF on the burning rate of Ammonium Perchlorate (AP)-Polyester propellant.

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Abstract is not available.

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Asymmetric diadenosine tetraphosphate (Ap(4)A) hydrolases degrade the metabolite Ap(4)A back into ATP and AMP. The three-dimensional crystal structure of Ap(4)A hydrolase (16 kDa) from Aquifex aeolicus has been determined in free and ATP-bound forms at 1.8 and 1.95 angstrom resolution, respectively. The overall three-dimensional crystal structure of the enzyme shows an alpha beta alpha-sandwich architecture with a characteristic loop adjacent to the catalytic site of the protein molecule. The ATP molecule is bound in the primary active site and the adenine moiety of the nucleotide binds in a ring-stacking arrangement equivalent to that observed in the X-ray structure of Ap(4)A hydrolase from Caenorhabditis elegans. Binding of ATP in the active site induces local conformational changes which may have important implications in the mechanism of substrate recognition in this class of enzymes. Furthermore, two invariant water molecules have been identified and their possible structural and/or functional roles are discussed. In addition, modelling of the substrate molecule at the primary active site of the enzyme suggests a possible path for entry and/or exit of the substrate and/or product molecule.

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Uracil DNA glycosylase (Ung)initiates the uracil excision repair pathway. We have earlier characterized the Y66W and Y66H mutants of Ung and shown that they are compromised by similar to 7- and similar to 170-fold, respectively in their uracil excision activities. In this study, fluorescence anisotropy measurements show that compared with the wild-type, the Y66W protein is moderately compromised and attenuated in binding to AP-DNA. Allelic exchange of ung in Escherichia coli with ung::kan, ungY66H:amp or ungY66W:amp alleles showed similar to 5-, similar to 3.0- and similar to 2.0-fold, respectively increase in mutation frequencies. Analysis of mutations in the rifampicin resistance determining region of rpoB revealed that the Y66W allele resulted in an increase in A to G (or T to C) mutations. However, the increase in A to G mutations was mitigated upon expression of wild-type Ung from a plasmid borne gene. Biochemical and computational analyses showed that the Y66W mutant maintains strict specificity for uracil excision from DNA. Interestingly, a strain deficient in AP-endonucleases also showed an increase in A to G mutations. We discuss these findings in the context of a proposal that the residency of DNA glycosylase(s) onto the AP-sites they generate shields them until recruitment of AP-endonucleases for further repair.

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In many IEEE 802.11 WLAN deployments, wireless clients have a choice of access points (AP) to connect to. In current systems, clients associate with the access point with the strongest signal to noise ratio. However, such an association mechanism can lead to unequal load sharing, resulting in diminished system performance. In this paper, we first provide a numerical approach based on stochastic dynamic programming to find the optimal client-AP association algorithm for a small topology consisting of two access points. Using the value iteration algorithm, we determine the optimal association rule for the two-AP topology. Next, utilizing the insights obtained from the optimal association ride for the two-AP case, we propose a near-optimal heuristic that we call RAT. We test the efficacy of RAT by considering more realistic arrival patterns and a larger topology. Our results show that RAT performs very well in these scenarios as well. Moreover, RAT lends itself to a fairly simple implementation.