Yarrol terrane of the northern New England Fold Belt: forearc or backarc?

The Upper Devonian to Lower Carboniferous volcanosedimentary rocks of the Yarrol terrane of the northern New England Fold Belt have previously been ascribed to a forearc basin setting. New data presented here, however, suggest that the Yarrol terrane developed as a backarc basin during the Middle to early Late Devonian. Based on field studies, we recognise four regionally applicable strati graphic units: (i) a basal, ?Middle to Upper Devonian submarine mafic volcanic suite (Monal volcanic facies association); (ii) the lower Frasnian Lochenbar beds that locally unconformably overlie the Monal volcanic facies association: (iii) the Three Moon Conglomerate (Upper Devonian - Lower Carboniferous): and (iv) the Lower Carboniferous Rockhampton Group characterised by the presence of oolitic limestone. Stratigraphic and compositional differences suggest the Monal volcanic facies association post-dates Middle Devonian silicic-dominated magmatism that was coeval with gold-copper mineralisation at Mt Morgan. The Lochenbar beds, Three Moon Conglomerate and Rockhampton Group represent a near-continuous sedimentary record of volcanism that changed in composition and style from mafic effusive (Late Devonian) to silicic explosive volcanism (Early Carboniferous). Palaeocurrent data from the Three Moon Conglomerate and Rockhampton Group indicate dispersal of sediment to the west and northwest, and are inconsistent with derivation from a volcanic-are source situated to the west (Connors-Auburn Arch). Geochemical data show that the Monal volcanic facies association ranges from tholeiitic subalkaline basalts to calc-alkaline basaltic andesite. Trace and rare-earth element abundances are distinctly MORE-like (e.g, light rare earth element depletion), with only moderate enrichment of the large-ion lithophile elements in some units, and negative Nb anomalies, suggesting a subduction-related signature. Basalts of the Monal volcanic facies association are best described as transitional between calc-alkali basalts and N-MORB. The elevated high field strength element contents (e.g. Zr, Y, Ti) are higher than modern island-are basalts, but comparable to basalts that floor modern backarc basins. This geochemical study, coupled with stratigraphic relationships, suggest that the eruption of backarc basin basalts followed widespread Middle Devonian, extension-related silicic magmatism (e.g. Retreat Batholith, Mt Morgan), and floored the Yarrol terrane. The Monal volcanic facies association thus shows similarities in its tectonic environment to the Lower Permian successions (e.g. Rookwood Volcanics) of the northern New England Fold Belt. These mafic volcanic sequences are interpreted to record two backarc basin-forming periods (Middle - Late Devonian and Late Carboniferous - Early Permian) during the Late Palaeozoic history of the New England Orogen. Silicic-dominated explosive volcanism, occurring extensively across the northern New England Fold Belt in the Early Carboniferous (Varrol terrane, Campwyn Volcanics, Drummond and Burdekin Basins), reflects another period of crustal melting and extension, most likely related to the opening of the Drummond Basin.

Bi-directional reflectance of corals

An assessment of the bi-directional reflectance distribution function (BRDF) of corals with different morphologies was undertaken using hyperspectral reflectance measurements. The highest variance in reflectance obtained at different viewing angles was found for the open branching Acropora colony, possibly attributed to branch orientation and internal shadow distribution. Spectral separation within and between features at the nominated sensor-viewing angles was greatest in the near infrared portion of the spectrum. The analysis of coral reef bi-directional reflectance properties and degree of internal shadowing holds potential for future assessment and information extraction relating to coral structural characteristics.

Cytological basis of photoresponsive behavior in a sponge larva

Ontogenetic changes in the photoresponse of larvae from the demosponge Reneira sp. were studied by analyzing the swimming paths of individual larvae exposed to diffuse white light. Larvae swam upward upon release from the adult, but were negatively phototactic until at least 12 hours after release. The larval photoreceptors are presumed to be a posterior ring of columnar monociliated epithelial cells that possess 120-mum-long cilia and pigment-filled protrusions. A sudden increase in light intensity caused these cilia to become rigidly straight. If the light intensity remained high, the cilia gradually bent over the pigmented vesicles in the adjacent cytoplasm, and thus covered one entire pole of the larva. The response was reversed upon a sudden decrease in light intensity. The ciliated cells were sensitive to changes in light intensity in larvae of all ages. This response is similar to the shadow response in tunicate larvae or the shading of the photoreceptor in Euglena and is postulated to allow the larvae to steer away from brighter light to darker areas, such as under coral rubble-the preferred site of the adult sponge on the reef flat. In the absence of a coordinating system in cellular sponges, the spatial organization and autonomous behavior of the pigmented posterior cells control the rapid responses to light shown by these larvae.

Tungsten isotope evidence from similar to 3.8-Gyr metamorphosed sediments for early meteorite bombardment of the Earth

The 'Late Heavy Bombardment' was a phase in the impact history of the Moon that occurred 3.8-4.0 Gyr ago, when the lunar basins with known dates were formed(1,2). But no record of this event has yet been reported from the few surviving rocks of this age on the Earth. Here we report tungsten isotope anomalies, based on the Hf-182-W-182 system (half-life of 9 Myr), in metamorphosed sedimentary rocks from the 3.7-3.8-Gyr-old Isua greenstone belt of West Greenland and closely related rocks from northern Labrador, Canada. As it is difficult to conceive of a mechanism by which tungsten isotope heterogeneities could have been preserved in the Earth's dynamic crust-mantle environment from a time when short-lived Hf-182 was still present, we conclude that the metamorphosed sediments contain a component derived from meteorites.

New W-isotope evidence for rapid terrestrial accretion and very early core formation

The short-lived Hf-182-W-182-isotope system is an ideal clock to trace core formation and accretion processes of planets. Planetary accretion and metal/silicate fractionation chronologies are calculated relative to the chondritic Hf-182-W-182-isotope evolution. Here, we report new high-precision W-isotope data for the carbonaceous chondrite Allende that are much less radiogenic than previously reported and are in good agreement with published internal Hf-W chronometry of enstatite chondrites. If the W-isotope composition of terrestrial rocks, representing the bulk silicate Earth, is homogeneous and 2.24 epsilon(182W) units more radiogenic than that of the bulk Earth, metal/silicate differentiation of the Earth occurred very early. The new W-isotope data constrain the mean time of terrestrial core formation to 34 million years after the start of solar system accretion. Early terrestrial core formation implies rapid terrestrial accretion, thus permitting formation of the Moon by giant impact while Hf-182 was still alive. This could explain why lunar W-isotopes are more radiogenic than the terrestrial value. Copyright (C) 2002 Elsevier Science Ltd.

On the overabundance of light rare earth elements in terrestrial zircons and its implication for Earth's earliest magmatic differentiation

We present whole-rock and zircon rare earth element (REE) data from two early Archaean gneisses (3.81 Ga and 3.64 Ga) from the Itsaq gneiss complex, south-west Greenland. Both gneisses represent extremely rare examples of unaltered, fresh and relatively undeformed igneous rocks of such antiquity. Cathodoluminescence imaging of their zircons indicates a single crystallisation episode with no evidence for either later metamorphic and/or anatectic reworking or inheritance of earlier grains. Uniform, single-population U/Pb age data confirm the structural simplicity of these zircons. One sample, a 3.64 Ga granodioritic gneiss from the Gothabsfjord, yields a chondrite-normalised REE pattern with a positive slope from La to Lu as well as substantial positive Ce and slight negative Eu anomalies, features generally considered to be typical of igneous zircon. In contrast, the second sample, a 3.81 Ga tonalite from south of the Isua Greenstone Belt, has variable but generally much higher light REE abundances, with similar middle to heavy REE. Calculation of zircon/melt distribution coefficients (D-REE(zircon/melt)) from each sample yields markedly different values for the trivalent REE (i.e. Ce and Eu omitted) and simple application of one set of D-REE(zircon/melt) to model the melt composition for the other sample yields concentrations that are in error by up to two orders of magnitude for the light REE (La-Nd). The observed light REE overabundance in the 3.81 Ga tonalite is a commonly observed feature in terrestrial zircons for which a number of explanations ranging from lattice strain to disequilibrium crystallisation have been proposed and are further investigated herein. Regardless of the cause of light REE overabundance, our study shows that simple application of zircon/melt distribution coefficients is not an unambiguous method for ascertaining original melt composition. In this context, recent studies that use REE data to claim that > 4.3 Ga Hadean detrital zircons originally crystallised from an evolved magma, in turn suggesting the operation of geological processes in the early Earth analogous to those of the present day (e.g. subduction and melting of hydrated oceanic crust), must be regarded with caution. Indeed, comparison of terrestrial Hadean and > 3.9 Ga lunar highland zircons shows remarkable similarities in the light REE, even though subduction processes that have been used to explain the terrestrial zircons have never operated on the Moon. (C) 2002 Elsevier Science B.V. All rights reserved.

Os gêneros de discurso, cenografia e ethos em discursos da obra O templo e a forca de Luiz Guilherme Santos Neves

A pesquisa busca mostrar como o discurso religioso do gênero sermão, na voz do enunciador Frei Gregório José Maria de Bene, pode influir na estratégia de adesão e convencimento dos escravos da região de Serra, província do Espírito Santo, para a construção da igreja do Queimado. O sermão citado é o recorte fundamental do discurso literário O Templo e a Forca (1999), recriado por Luiz Guilherme Santos Neves, analisado a partir de cena englobante legitimadora. O trabalho insere-se nos estudos da Analise do Discurso (AD) de linha francesa, pelo referencial teórico de Dominique Maingueneau, que nos orientará quanto às cenografias do padre, sua imagem de enunciador, as condições de produção do sermão, ressaltando elementos que interagem no embate, visando à sociedade da época e às questões culturais dos envolvidos na eclosão da revolta. O principal objetivo é examinar as cenas de enunciação e como se constrói o ethos religioso em cada cena e suas variadas funções. É elementar dizer que o religioso se reconstrói a cada momento a partir do comprometimento com as situações de comunicação. Para maior entendi-mento, dizemos que essas diversas reconstruções apresentam nos discursos diferentes encenações desse tão fomentado religioso com suas estratégias de adesão, apresentando-se ora com a imagem daquele que fala em nome de Deus, preza a docilidade da vida do campo à sombra das andirobeiras gigantes onde se pode sentir o silêncio que convida à contemplação e à prece; ora aquele comprometido com seus propósitos interesseiros e pessoais. Fala para não ser entendido, e o que vale é erguer a casa de São José sem poupar a carne e o sangue das mortes que virão. Importa ressaltar que sempre há possibilidade de olhar ingênuo sobre texto religioso, que, conforme Main-gueneau (2010), só é legível relacionado a vasto intertexto que contribuirá para estruturar o discurso. Para enriquecer ainda mais este estudo, afora o gênero sermão usamos recortes que estruturam o discurso de Neves e sinalizam as variadas cenografias e a forma como se constituem enquanto gêneros: Diálogo interior – momentos solitários do frade – Visão do frade e Monólogo; Diálogo Compartilhado – segmenta diálogos entre o enunciador e seus vários co-enunciadores, que estruturam os acontecimentos do discurso; e o gênero exortação, do padre aos escravos. Os recortes são momentos de grandes embates recriados pelo autor, em discurso leve fazendo seu leitor transitar prazerosamente junto ao frade entre as suas variadas imagens nos discursos. Levando o leitor a acreditar tratar-se de cenas relacionadas ao gênero cômico. E talvez o fosse, se não terminasse em revolta.

Vasco da Gama and the Later Portuguese Colonial Presence in India

A chegada de Vasco da Gama à Índia marcou o início de uma nova era na história da Índia e do mundo. Foi um encontro marcado por colaboração e resistências. Tanto os indianos como os portugueses faziam cedências por necessidade ou por conveniências. Não se pode ignorar neste processo o impacto dos renegados portugueses que se espalharam pela Asia toda. Era o resultado da "grande soltura" após a morte de Afonso de Albuquerque que acreditava numa economia comandada. O império da sombra, tão bem descrito por Fernão Mendes Pinto prevaleceu.

A ponte quebrada: sobre o papel da linguagem como forma de conhecimento e comunicação em romances pós-modernos

Que a linguagem consista num dos modos essenciais para conhecer o homem e o mundo é um dos fundamentos da consciência europeia. Ao mesmo nível encontramos a convicção de que a linguagem fornece uma ponte (talvez a ponte por excelência) para estabelecer comunicação. Nalguns períodos de história literária, deparamo-nos com um certo cepticismo em relação a este simples pressuposto: ao longo do romantismo, por exemplo, diversos autores exprimiram os limites da linguagem. Durante a “grande crise européenne”, o romance A Carta de Lord Chandos revelou, provavelmente, o cepticismo mais profundo quanto à capacidade da linguagem abrir caminho ao conhecimento do mundo e do sujeito. Um crise semelhante manifesta-se em Austerlitz de Wolfgang Sebald, um romance representativo da pósmodernidade. Num determinado momento, o protagonista “perde” a linguagem e, por conseguinte, a segurança de uma identidade pessoal consolidada. De forma menos afirmativa mas igualmente clara, surge ainda um momento similar em Moon Palace de Paul Auster, outro ícone pós-moderno. Uma análise destes dois romances pode ajudar-nos a compreender uma questão de extrema relevância: até que ponto é que a linguagem abre caminho ao auto-conhecimento e à comunicação?

Constructing good deals in discrete time arbitrage-free dynamic pricing models

Recent literature has proved that many classical pricing models (Black and Scholes, Heston, etc.) and risk measures (V aR, CV aR, etc.) may lead to “pathological meaningless situations”, since traders can build sequences of portfolios whose risk leveltends to −infinity and whose expected return tends to +infinity, i.e., (risk = −infinity, return = +infinity). Such a sequence of strategies may be called “good deal”. This paper focuses on the risk measures V aR and CV aR and analyzes this caveat in a discrete time complete pricing model. Under quite general conditions the explicit expression of a good deal is given, and its sensitivity with respect to some possible measurement errors is provided too. We point out that a critical property is the absence of short sales. In such a case we first construct a “shadow riskless asset” (SRA) without short sales and then the good deal is given by borrowing more and more money so as to invest in the SRA. It is also shown that the SRA is interested by itself, even if there are short selling restrictions.

Idiosyncratic risk really drives stock returns; Spanish evidence

Following the theoretical model of Merton (1987), we provide a new perspective of study about the role of idiosyncratic risk in the asset pricing process. More precisely, we analyze whether the idiosyncratic risk premium depends on the idiosyncratic risk level of an asset as well as the vatriation in the market-wide measure of idiosyncratic risk. As expected, we obtain a net positive risk premium for the Spanish stock market over the period 1987-2007. Our results show a positive relation between returns and individual indiosyncratic risk levels and a negative but lower relation with the aggregate measure of idiosyncratic risk. These findings have important implications for portfolio and risk management and contribute to provide a unified and coherent answer for the main and still unsolved question about the idiosyncratic risk puzzle: whether or not there exists a premium associated to this kind of risk and the sign for this risk premium.

Intra-population plasticity of Anopheles darlingi's (Diptera, Culicidae) biting activity patterns in the state of Amapá, Brazil

OBJECTIVE: To assess the variation in Anopheles darlingi's biting activity compared to An. marajoara in the same locality and to biting activity data from other regions. METHODS: Using human bait, eight observations of the biting activity of An. darlingi and An. marajoara were carried out during 1999 and 2000 in the municipality of São Raimundo do Pirativa, state of Amapá, Brazil. Each observation consisted of three consecutive 13-hour collections, close to full moon. There were shifts of collectors in the observation points and nocturnal periods. RESULTS: An. darlingi revealed considerable plasticity of biting activity in contrast to An. marajoara, which showed well-defined crepuscular biting peaks. No significant correlation between density and biting activity was found, but a significant correlation existed between time and proportional crepuscular activity, indicating underlying ecological processes not yet understood. Two of the four available data sets having multiple observations at one locality showed considerable plasticity of this species' biting patterns as well. CONCLUSION: Intra-population variation of biting activity can be as significant as inter-population variation. Some implications in malaria vector control and specific studies are also discussed.

Estudo da eficiência de sistemas fotovoltaicos

Mestrado em Engenharia Química. Ramo optimização energética na indústria química

O conselho geral: um desafio estratégico à autonomia

Nos últimos vinte e cinco anos o tema da autonomia e da administração e gestão escolar tem ocupado um lugar relevante na agenda política dos sucessivos Governos da República e na preocupação dos diferentes parceiros educativos. Rara tem sido a maioria política que resiste a dar o seu contributo sobre esta matéria, com o objetivo sempre confesso de outorgar maior autonomia às escolas. No enquadramento teórico da nossa investigação começamos por abordar a emergência do conceito de autonomia, nas suas diferentes dimensões e nos seus distintos significados. Não esquecemos também a analise das questões relacionadas com a problemática, cada vez mais atual da regulação múltipla. Analisamos de seguida a evolução da legislação portuguesa, operada a partir da publicação da Lei de Bases do Sistema Educativo com especial destaque às propostas de configuração dos órgãos de Direção e de Gestão das escolas e das competências atribuídas a cada um deles produzido pela CRSE e pelos decretos-leis 43/89, 172/91, 115-A/98 e 75/2008. A investigação empírica teve como objeto de análise dois agrupamentos localizados em concelhos distintos da Área Metropolitana de Lisboa, e procurou determinar se o conselho geral de cada uma dessas unidades orgânicas, assume na totalidade as competências que lhe são conferidas pelo quadro legislativo em vigor, e nessa medida como se articula com os outros órgãos da direção no processo de tomada de decisão. Simultaneamente fizemos o contraponto com a imagem que os intervenientes na gestão intermédia de cada um dos agrupamentos construíram sobre o seu conselho geral e das relações de poder que se estabelecem no interior de cada uma das organizações. Para corresponder aos pressupostos da nossa investigação entrevistaram-se os diretores e os presidentes dos conselhos gerais e facultámos questionários aos docentes que desempenhavam cargos nos dois agrupamentos. Concluímos, em função do que pudemos analisar, que embora o conselho geral veja o seu papel na organização da escola formalmente reconhecido não consegue desempenhar na totalidade as funções que lhe são incumbidas, já que defronta o poder real do diretor e o poder oculto do conselho pedagógico, encontrando dificuldades em libertar-se do reino das sombras.

Modelação de torre eólica: controlo e desempenho

Dissertação para obtenção do grau de Mestre em Engenharia Electrotécnica Ramo de Energia