473 research outputs found

    Out in Appalachia: Leaving the Closet in the Mountains

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    A thesis presented to the faculty of the Caudill College of Arts, Humanities, and Social Sciences at Morehead State University in partial fulfillment of the requirements for the degree of Master of Arts by Jeffrey C. Cawood, Jr. on April 28, 2018

    A change in the geodynamics of continental growth 3 billion years ago

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    Continental Growth Spurts The appearance and persistence of continents through geologic time has influenced most processes on Earth, from the evolution of new species to the climate. The relative proportion of newly formed crust compared to reworked, or destroyed, older crust reveals which processes controlled continental growth. Based on the combined analyses of Hf-Pb and O isotopes in zircon minerals, Dhuime et al. (p. 1334 ) measured continuous but variable rates of new crustal production throughout Earth's history. Increased rates of crustal destruction starting around 3 billion years ago coincide with the onset of subduction-drive plate tectonics, slowing down the overall rate of crustal growth. </jats:p

    Unraveling the New England orocline, east Gondwana accretionary margin

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    The New England orocline lies within the Eastern Australian segment of the Terra Australis accretionary orogen and developed during the late Paleozoic to early Mesozoic Gondwanide Orogeny (310–230 Ma) that extended along the Pacific margin of the Gondwana supercontinent. The orocline deformed a pre-Permian arc assemblage consisting of a western magmatic arc, an adjoining forearc basin and an eastern subduction complex. The orocline is doubly vergent with the southern and northern segments displaying counter-clockwise and clockwise rotation, respectively, and this has led to contrasting models of formation. We resolve these conflicting models with one that involves buckling of the arc system about a vertical axis during progressive northward translation of the southern segment of the arc system against the northern segment, which is pinned relative to cratonic Gondwana. Paleomagnetic data are consistent with this model and show that an alternative model involving southward motion of the northern segment relative to the southern segment and cratonic Gondwana is not permissible. The timing of the final stage of orocline formation (~270–265 Ma) overlaps with a majorgap in magmatic activity along this segment of the Gondwana margin, suggesting that northward motion and orocline formation were driven by a change from orthogonal to oblique convergence and coupling between the Gondwana and Pacific plates

    A Paleoproterozoic intra-arc basin associated with a juvenile source in the Southern Brasilia Orogen : application of U-Pb and Hf-Nd isotopic analyses to provenance studies of complex areas

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    A. Westin and M.C. Campos Neto acknowledge support from São Paulo Research Foundation (FAPESP) through grants 2011/13311-9, 2013/13530-8 and 2013/19095-1. A. Westin is a grant holder at FAPESP and M. C. Campos Neto is a CNPq researcher. P. A. Cawood, C. J. Hawkesworth and H. Delavault acknowledge support from Natural Environment Research Council grant NE/J021822/1.Early Proterozoic sedimentary basins are an important record of crust generation processes and consequently a fundamental key to unravelling Earth's evolution through geological time. Sediments within the basins are typically deformed and metamorphosed by subsequent tectonothermal events, which can obliterate their links to source terranes. Nd-whole-rock and detrital zircon U-Pb and Lu-Hf isotopic analyses are among the most reliable tools to be used in provenance investigations, since zircon is a resilient mineral and the Sm-Nd system is not extensively modified during metamorphism. These methods have been applied to a study of the provenance and tectonic setting of the São Vicente Complex, preserved in a Neoproterozoic passive margin related allochthon within the Southern Brasilia Orogen. The complex consists of siliciclastic and calc-silicate gneisses with mafic and minor ultramafic rocks, which were deformed and metamorphosed during late Neoproterozoic collision between the Paranapanema Block and the São Francisco-Congo plate. Detrital zircons indicate derivation from a juvenile Paleoproterozoic source terrane (peaks of crystallisation ages of ca. 2130 Ma, 2140 Ma and 2170 Ma; ɛHft between +0.1 and +6.0; NdTDM = 2.31-2.21 Ga; ɛNdt = +1.6 to +2.8), with a minor contribution from older continental crust. Interlayered amphibolite rocks, with juvenile signatures (ɛHft = +5.8 to +8.2; NdTDM = 2.14 and 2.30 Ga; ɛNdt = +2.2 and +3.2), yielded similar ages of 2136 ± 17 and 2143 ± 14 Ma, suggesting syn-sedimentary magmatism. Thus, the maximum age of deposition at around 2130 Ma represents the best estimate of the depositional age of the complex. The dominance of detrital zircons ages close to the age of deposition, along with syn-sedimentary magmatism, imply a convergent margin basin tectonic environment for the São Vicente Complex, with similarities to fore arc basin and trench deposits. Amphibolite and meta-sedimentary rocks point to important juvenile magmatism around 2.14 Ga. Juvenile Rhyacian (ca. 2.1 Ga) granite-granodiorite-tonalite orthogneisses with arc-related geochemical signatures (Pouso Alegre Complex) that override the São Vicente Complex, are the probable main source of detritus within the complex. Both basin and source were part of the southern edge of the São Francisco plate during the assembly of West Gondwana, and served as sources for early Neoproterozoic passive margin related basins. The age of intrusive anorogenic A-type Taguar granite indicates that by 1.7 Ga the São Vicente Complex was in a stable tectonic environment.PostprintPeer reviewe

    Increasing the density of nanomedicines improves their ultrasound-mediated delivery to tumours

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    AbstractNanomedicines have provided fresh impetus in the fight against cancer due to their selectivity and power. However, these agents are limited when delivered intravenously due to their rapid clearance from the bloodstream and poor passage from the bloodstream into target tumours. Here we describe a novel stealthing strategy which addresses both these limitations and thereby demonstrate that both the passive and mechanically-mediated tumour accumulation of the model nanomedicine adenovirus (Ad) can be substantially enhanced. In our strategy gold nanoparticles were thoroughly modified with 2kDa polyethyleneglycol (PEG) and then linked to Ad via a single reduction-cleavable 5kDa PEG. The resulting Ad–gold–PEG construct was compared to non-modified Ad or conventionally stealthed Ad–poly[N-(2-hydroxypropyl)methacrylamide] (Ad–PHPMA). Notably, although Ad–gold–PEG was of similar size and surface charge to Ad–PHPMA the increase in density, resulting from the inclusion of the gold nanoparticles, provided a substantial enhancement of ultrasound-mediated transport. In an in vitro tumour mimicking phantom, the level and distance of Ad–gold–PEG transport was shown to be substantially greater than achieved with Ad–PHPMA. In in vivo studies 0.1% of an unmodified Ad dose was shown to accumulate in tumours, whereas over 12% of the injected dose was recovered from the tumours of mice treated with Ad–gold–PEG and ultrasound. Ultimately, a significant increase in anti-tumour efficacy resulted from this strategy. This stealthing and density-increasing technology could ultimately enhance clinical utility of intravenously delivered nanoscale medicines including viruses, liposomes and antibodies

    A análise da divulgação de informação nos relatórios intercalares e sua relação com a performance financeira: o caso dos relatórios semestrais das instituições não financeiras do PSI 20

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    Dissertação/Trabalho de Projeto/Relatório de Estágio submetida como requisito parcial para obtenção do grau de Mestre em Contabilidade e FinançasA divulgação da informação financeira é um fator chave para a tomada de decisão dos diferentes stakeholders, sendo de importância acrescida em empresas cotadas. Desta forma, diferentes entidades reguladoras têm exigido, que as empresas relatarem a sua atividade de forma mais tempestiva junto dos investidores e ao público em geral. Neste âmbito, o presente estudo tem como principal objetivo avaliar o nível de divulgação da informação financeira intercalar e analisar a possível relação com um conjunto de indicadores, essencialmente ao nível da performance financeira (rendibilidade dos ativos, rendibilidade dos capitais próprios, nível de endividamento, grau de internacionalização e dimensão da empresa). Efetuou-se uma análise de conteúdo aos relatórios e contas semestrais das empresas cotadas no PSI 20 no ano de 2015 e adaptou-se o índice de Santos e Martins (2016) para avaliar o nível de divulgação de informação. Os resultados obtidos apontam que as empresas estudadas possuem, em média, um nível de divulgação de 39,67% e as mesmas atribuem mais importância à divulgação de informações relacionadas com a categoria 2 “Histórico dos resultados”, categoria 1 “Informações gerais” e categoria 5 “gestão da empresa: discussão e análise” (71,11%, 46,06% e 42,67%, respetivamente). Enquanto que, os CTT e a Teixeira Duarte apresentam os maiores índices de divulgação intercalar (IDI) (63,41% e 56,10%, respetivamente), liderando o grupo de empresas do “nível 1”, a EDP Renováveis e a Impresa possuem o nível mais reduzido (17,07% e 14,63%, respetivamente). Adicionalmente, constatou-se que as empresas com um IDI acima da média, “nível 1”, possuem, em média, uma maior rendibilidade dos capitais próprios, nível de endividamento (incluindo a ótica do passivo remunerado) e uma dimensão superior, do que as empresas com menor divulgação (“nível 2”).The disclosure of financial information is a key factor for the decision-making of the different stakeholders, being of major importance for listed companies. In this way, different regulatory entities have demanded that companies report their activity more timely to investors and the public. In this context, the main objective of this study is to evaluate the level of disclosure of interim financial information and to analyze the possible relationship with a set of indicators, mainly in terms of financial performance (return on assets, return on equity, level of indebtedness, degree of internationalization and company size). We perform a content analysis to the semi-annual reports of companies listed in the PSI 20, in the year 2015, and adapting Santos and Martins (2016) disclosure index, we evaluate the level of disclosed information. The obtained results, indicate that companies have, on average, a level of disclosure of 39,67% and they attach greater importance to the disclosure of information related to category 2 "History of results", category 1 "General information" and category 5 "Management of the company: discussion and analysis" (71.11%, 46.06% and 42.67%, respectively). While CTT and Teixeira Duarte have the highest indices of interim disclosure (IDI) (63.41% and 56.10%, respectively), leading the "level 1" group of companies, EDPR and Impresa have the lowest level (17.07% and 14.63%, respectively). In addition, it was found that companies with an above-average IDI, "level 1", have, on average, a higher return on equity, a higher level of indebtedness (including the perspective of remunerated liabilities) and a larger size, than the companies with less disclosures ("level 2")

    Extensive crustal extraction in Earth’s early history inferred from molybdenum isotopes

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    Estimates of the volume of the earliest crust based on zircon ages and radiogenic isotopes remain equivocal. Stable isotope systems, such as molybdenum, have the potential to provide further constraints but remain underused due to the lack of complementarity between mantle and crustal reservoirs. Here we present molybdenum isotope data for Archaean komatiites and Phanerozoic komatiites and picrites and demonstrate that their mantle sources all possess subchondritic signatures complementary to the superchondritic continental crust. These results confirm that the present-day degree of mantle depletion was achieved by 3.5 billion years ago and that Earth has been in a steady state with respect to molybdenum recycling. Mass balance modelling shows that this early mantle depletion requires the extraction of a far greater volume of mafic-dominated protocrust than previously thought, more than twice the volume of the continental crust today, implying rapid crustal growth and destruction in the first billion years of Earth’s history

    In assisted reproduction by IVF or ICSI, the rate at which embryos develop to the blastocyst stage is influenced by the fertilization method used: a split IVF/ICSI study

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    PURPOSE: To compare in vitro fertilization (IVF) with intracytoplasmic sperm injection (ICSI) in regard to post-fertilization development and outcome with the purpose of ascertaining the most effective fertilization method for assisted reproduction. METHODS: A retrospective cohort study of 136 split IVF/ICSI cycles (where sibling oocytes are fertilized by two different methods using the same sperm sample). RESULTS: IVF-derived embryos developed to the blastocyst stage at a significantly faster rate than ICSI-derived embryos. There was no significant difference in fertilization or livebirth rates between the two fertilization methods. CONCLUSIONS: For patients with sperm progressive motility ≥ 1.0 × 106/ml (who usually constitute the majority of patients), no significant difference between the two fertilization methods was found in regard to fertilization rate or livebirth rate. Remaining factors influencing choice between the two methods appear to be restricted to convenience, financial considerations and concern with regard to possible perpetuation of genetically linked infertility to future generations

    Sinus lifting before Le Fort I maxillary osteotomy: a suitable method for oral rehabilitation of edentulous patients with skelettal class-III conditions: review of the literature and report of a case

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    BACKGROUND: Functional rehabilitation of patients afflicted with severe mandibular and maxillary alveolar atrophy might be challenging especially in malformed patients. METHODS: Treatment planning using sinus lifting and implant placement before Le Fort I maxillary osteotomy in a patient with severe mandibular and posterior maxillary alveolar atrophy and skelettal class-III conditions due to cleft palate are described. RESULTS: A full functional and esthetic rehabilitation of the patient was achieved by a stepwise surgical approach performed through sinus lifting as the primary approach followed by implant placement and subsequent Le Fort I maxillary osteotomy to correct the maxillo-mandibular relation. CONCLUSION: Stabilisation of the maxillary complex by a sinus lifting procedure in combination with computer aided implant placement as preorthodontic planning procedure before Le Fort I maxillary osteotomy seems to be suitable in order to allow ideal oral rehabilitation especially in malformed patients
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