333 research outputs found

    Distribuição espacial de minerais pesados nos sedimentos superficiais da Plataforma Continental Oeste do Ceará, Nordeste do Brasil

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    The continental shelf sediments of the west coast of Ceará were investigated about their texture, calcium carbonate and heavy minerals with the generation of digital bottom model of this shelf. Multivariate statistics analyses were applied for mineralogical data to aid interpretation of heavy mineral provenance. Despite the predominance of carbonate sedimentation, the western Ceará continental shelf presents significant concentrations of heavy mineral (4.54 %), resulting in placer deposits in litoclastic and litobioclastic sands located further east of the study area (Fortaleza Chart). It was possible identify irregularities in the submarine bottom, which indicate paleochannels and ancient shoreline and support heavy minerals concentration. The mineral assemblage (ilmenite, tourmaline, epidote, hornblende, monazite, staurolite, sillimanite, rutile, magnetite, zircon, andalusite, kyanite, garnet, leucoxene, diopside, apatite, spinel and cassiterite) suggests regional contributions of the reworking of sediments Barreiras Formation and local contribuition of metamorphic rocks of Ceará Complex. Crystalline basement outcrops on the continental shelf near Pecém Port (São Gonçalo do Amarante) contribute directly to sediment supply of terrigenous, hence the heavy minerals are concentrated in these places. Multivariate statistics distinguish two types of sources which were described above, however it should take attention to other contributions as coastal black sands, present fluvial supply (continental), past fluvial supply (drowned river valleys) and marine sediments from longshore drift.Os sedimentos da plataforma continental oeste cearense foram investigados com relação à sua textura, conteúdo de carbonato de cálcio e minerais pesados com a geração do modelo digital de fundo desta plataforma. A estatística multivariada foi aplicada aos dados mineralógicos para auxiliar na interpretação da proveniência dos minerais pesados. A plataforma continental oeste cearense, apesar da predominância da sedimentação carbonática, apresenta concentrações importantes de minerais pesados (4,54 %), originando depósitos do tipo plácer nas areias litoclásticas e litobioclásticas situadas mais a leste da área estudada (Folha Fortaleza). Foram identificadas irregularidades indicativas de paleocanais e antigas linhas de praia que favorecem a concentração de minerais pesados. A assembleia mineral (ilmenita, turmalina, epídoto, hornblenda, monazita, estaurolita, sillimanita, rutilo, magnetita, zircão, andaluzita, cianita, granada, leucoxênio, diopsídio, apatita, espinélio e cassiterita) sugere contribuições regionais do retrabalhamento dos sedimentos da Formação Barreiras e contribuição local das rochas metamórficas do Complexo Ceará. Afloramentos do embasamento cristalino na plataforma continental próximos ao Porto do Pecém (São Gonçalo do Amarante) contribuem diretamente no aporte de sedimentos terrígenos e são nesses locais que os minerais pesados se concentram. A estatística multivariada discriminou os dois tipos de proveniências anteriormente descritos, contudo devem-se levar em consideração outras contribuições como das areias pretas costeiras, aporte fluvial atual (continental) e pretérito (vales fluviais afogados) e sedimentos marinhos de deriva litorânea

    Morfodinâmica de praias dominadas por mesomarés na Planície Arenosa de Almofala, NW do Ceará (Brasil)

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    The morphodynamics of the oceanic beaches of the Almofala sandy plain varies due to the oceanographic parameters (waves, tides and coastal currents), meteorological (rains, winds and storms) and anthropogenic (shrimp farms). The objectives are to analyze the processes of progradation and retrogradation of the coastline and the morphodynamics of beaches. The Almofala, Barreira and Torrões beaches are located on the west coast of Ceará. The methodology consisted of the acquisition of topographical data (DGPS), oceanographic parameters (period, direction, high wave and tidal range) and sediments samples. These beaches had RTR with dominate wave. The parameter ε showed longitudinal bar and runnel system on the Almofala and Torrões beaches, and reflective on the Barreira beach. The parameter Ω showed intermediate terrace stage on the beach at the low tide on the Almofala beach and dissipative stage on the Barreira and Torrões beaches, with a predominance of fine grain sand (44%) and on the Almofala and Torrões beaches and medium sand (29%) on the Barreira beach. These beaches are semi-exposed, operating winds (5,5 m/s) and waves (0,56 m), with erosion in the Barreira beach (-64,5 m³) and Torrões beach (-72,1 m³), and accretion (62,83 m³) in the Almofala beach, according year of 2007.A morfodinâmica nas praias oceânicas da planície arenosa de Almofala varia em função de parâmetros oceanográficos (ondas, marés e correntes costeiras), meteorológicos (ventos, tempestades e chuvas) e antrópicos (fazendas de camarão). Os objetivos do trabalho são analisar os processos de progradação e retrogradação da linha de costa e a morfodinâmica das praias. As praias de Almofala, da Barreira e de Torrões localizam-se na costa oeste do Ceará. A metodologia consistiu na aquisição de dados topográficos (DGPS), oceanográficos (ondas - período, direção e altura da onda, e maré) e de amostras de sedimentos praiais. Estas praias apresentaram RTR com onda dominante. O parâmetro ε mostrou sistema barra e calha longitudinal nas praias de Almofala e de Torrões, e estágio reflectivo na praia da Barreira. O parâmetro Ω apresentou estágios predominantes de terraço de maré baixa na praia de Almofala, e dissipativo nas praias da Barreira e de Torrões, com predomínio de areia fina (44%) nas praias de Almofala e Torrões, e areia média (29%) na praia da Barreira. Estas praias são semi-expostas, com atuação de ventos (5,5 m/s) e ondas (0,56 m de altura), com erosão nas praias da Barreira (-64,5 m³) e de Torrões (-72,1 m³), e acresção (62,83 m³) na praia da Almofala, segundo dados de 2007

    Extraction techniques and clean-up procedures for the determination of pahs in sediments of the Ceará coast

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    Extraction and clean-up are essential points in polycyclic aromatic hydrocarbon (PAHs) analysis in a solid matrix. This work compares extraction techniques and clean-up procedures for PAH analysis. PAH levels, their toxicological significance and source were also evaluated in the waters of the Cocó and Ceará rivers. The efficiency of PAH recovery was higher for the soxhlet and ultrasonic techniques. PAH recovery varied from 69.3 to 99.3%. Total PAH concentration (ΣHPA) varied from 720.73 to 2234.76 µg kg-1 (Cocó river) and 96.4 to 1859.21 µg kg-1 (Ceará river). The main PAH sources are pyrolytic processes and the levels were classified as medium so that adverse effects are possible

    The First Provenance Challenge

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    The first Provenance Challenge was set up in order to provide a forum for the community to help understand the capabilities of different provenance systems and the expressiveness of their provenance representations. To this end, a Functional Magnetic Resonance Imaging workflow was defined, which participants had to either simulate or run in order to produce some provenance representation, from which a set of identified queries had to be implemented and executed. Sixteen teams responded to the challenge, and submitted their inputs. In this paper, we present the challenge workflow and queries, and summarise the participants contributions

    Staphylococcus aureus isolates colonizing and infecting cirrhotic and liver-transplantation patients: comparison of molecular typing and virulence factors

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    Abstract\ud \ud Background\ud \ud S. aureus is an important agent of colonization and infection in liver transplant patients. It harbors several virulence factors that can increase its pathogenicity. However, studies of virulence and molecular typing of MRSA in cirrhotic and liver transplantation patients are scarce.\ud \ud \ud Results\ud Here we use SCCmec, PFGE, spa typing, MLST and virulence factors to characterize MRSA isolates in pre and post liver transplantation patients. Sixteen (13 %) of 126 cirrhotic and 15 of the 64 liver-transplanted patients (23 %) were colonized by MRSA (p = 0.091). SCCmec types I, II and III that are generally associated with nosocomial infections were identified in 91 % of the isolates. None of the isolates carried PVL, adhesion factors and fib gene. Only three MRSA colonized isolates carried tst gene and were characterized as SCCmec type I and t149. Ten spa types and five STs were identified; t002 and ST105 were the most frequent profiles. Spa types and ST1510 never described in Brazil and a new spa type t14789 were identified. Nineteen PFGE subtypes were found and grouped into nine types. There was a predominant cluster, which was related to the New York/Japanese epidemic clone and harboured SCCmec type II identified in both cirrhotic and post-transplantation patients. Based on SCCmec and virulence factors the MRSA isolates belonged to NY/Jpn clone seen be more similar to the USA100 MRSA isolates.\ud \ud \ud Conclusions\ud Although without significance, liver-transplantation was more frequently colonized by MRSA than cirrhotic patients. The most frequent SCCmec was type II, and the predominant cluster was related to the New York/Japanese clone. A new spa t14789, and ST1510 never reported in Brazil were identified.The authors are grateful to financial support by FAPESP (Fundação de\ud Amparo à pesquisa do Estado de São Paulo) and CNPQ (Conselho Nacional\ud de Desenvolvimento Científico e Tecnológico)

    A computational method for the identification of dengue, zika and chikungunya virus species and genotypes

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    In recent years, an increasing number of outbreaks of Dengue, Chikungunya and Zika viruses have been reported in Asia and the Americas. Monitoring virus genotype diversity is crucial to understand the emergence and spread of outbreaks, both aspects that are vital to develop effective prevention and treatment strategies. Hence, we developed an efficient method to classify virus sequences with respect to their species and sub-species (i.e. serotype and/or genotype). This tool provides an easy-to-use software implementation of this new method and was validated on a large dataset assessing the classification performance with respect to whole-genome sequences and partial-genome sequences.publishersversionpublishe

    Uncovering the Multibiome Environmental and Earth System Legacies of Past Human Societies

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    It has been argued that we have now entered the Anthropocene, a proposed epoch in which humans are having a dominant impact on the Earth system. While some geologists have sought to formalize the Anthropocene as beginning in the mid-twentieth century, its social, geophysical, and environmental roots undoubtedly lie deeper in the past. In this review, we highlight the ways in which human activities across the major biomes of our planet significantly altered parts of the Earth system prior to the Industrial Age. We demonstrate ways in which novel, multidisciplinary approaches can provide detailed insights into long-term human–environment–Earth system interactions. We argue that there is clear evidence for lasting Earth system legacies of pre-Industrial human societies and that archaeology, paleoecology, and historical ecology can provide important, practical insights to help navigate current and future relationships with the planet in more equitable and sustainable ways

    Indirect signals of spawning aggregations of three commercial reef fish species on the continental shelf of Bahia, east coast of Brazil

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    AbstractLutjanus analis (Mutton snapper), Lutjanus jocu(Dog snapper) and Mycteroperca bonaci (Black grouper) are reef fishes of high commercial value, and are among the principal exploited reef resources on the eastern and northeastern coast of Brazil. These species share the habit of forming transient spawning aggregations, predictable in time and space, which leaves them particularly vulnerable. The present study aimed to obtain indirect indicators of periods and places of spawning aggregations for these species, based on the exploratory analysis of available data on commercial catches and fishing efforts in Southern Bahia. Line fishery landings data were monitored in 12 locations in the region, and catch records of Mutton snapper (1320 landings), Dog snapper (654) and Black grouper (1162) were analyzed. A strategy was developed for exploratory analysis of monthly CPUE variation and individual distribution of CPUE per trip. The results showed the occurrence of aggregations in 26 specific sites, with values of relative abundance far above the annual mean, during spring/summer and autumn/winter. The occurrence of these anomalous catches was validated with the fishermen responsible for respective fishing trips. Additional studies are needed to confirm spawning activity at these sites. Analysis of inter-annual variation suggests a decreasing trend in relative abundance of Black grouper and Mutton snapper, possibly associated with unregulated fishing of spawning aggregations
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