989 resultados para SAO-FRANCISCO CRATON


Relevância:

30.00% 30.00%

Publicador:

Resumo:

Background: Over the last century the incidence of cutaneous melanoma has increased worldwide, a trend that has also been observed in Brazil. The identified risk factors for melanoma include the pattern of sun exposure, family history, and certain phenotypic features. In addition, the incidence of melanoma might be influenced by ethnicity. Like many countries, Brazil has high immigration rates and consequently a heterogenous population. However, Brazil is unique among such countries in that the ethnic heterogeneity of its population is primarily attributable to admixture. This study aimed to evaluate the contribution of European ethnicity to the risk of cutaneous melanoma in Brazil. Methodology/Principal Findings: We carried out a hospital-based case-control study in the metropolitan area of Sao Paulo, Brazil. We evaluated 424 hospitalized patients (202 melanoma patients and 222 control patients) regarding phenotypic features, sun exposure, and number of grandparents born in Europe. Through multivariate logistic regression analysis, we found the following variables to be independently associated with melanoma: grandparents born in Europe-Spain (OR = 3.01, 95% CI: 1.03-8.77), Italy (OR = 3.47, 95% CI: 1.41-8.57), a Germanic/Slavic country (OR = 3.06, 95% CI: 1.05-8.93), or >= 2 European countries (OR = 2.82, 95% CI: 1.06-7.47); eye color-light brown (OR = 1.99, 95% CI: 1.14-3.84) and green/blue (OR = 4.62; 95% CI 2.22-9.58); pigmented lesion removal (OR = 3.78; 95% CI: 2.21-6.49); no lifetime sunscreen use (OR = 3.08; 95% CI: 1.03-9.22); and lifetime severe sunburn (OR = 1.81; 95% CI: 1.03-3.19). Conclusions: Our results indicate that European ancestry is a risk factor for cutaneous melanoma. Such risk appears to be related not only to skin type, eye color, and tanning capacity but also to others specific characteristics of European populations introduced in the New World by European immigrants.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Although some studies have shown diversity in HIV integrase (IN) genes, none has focused particularly on the gene evolving in epidemics in the context of recombination. The IN gene in 157 HIV-1 integrase inhibitor-naive patients from the Sao Paulo State, Brazil, were sequenced tallying 128 of subtype B (23 of which were found in non-B genomes), 17 of subtype F (8 of which were found in recombinant genomes), 11 integrases were BF recombinants, and 1 from subtype C. Crucially, we found that 4 BF recombinant viruses shared a recurrent recombination breakpoint region between positions 4900 and 4924 (relative to the HXB2) that includes 2 gRNA loops, where the RT may stutter. Since these recombinants had independent phylogenetic origin, we argue that these results suggest a possible recombination hotspot not observed so far in BF CRF in particular, or in any other HIV-1 CRF in general. Additionally, 40% of the drug-naive and 45% of the drug-treated patients had at least 1 raltegravir (RAL) or elvitegravir (EVG) resistance-associated amino acid change, but no major resistance mutations were found, in line with other studies. Importantly, V151I was the most common minor resistance mutation among B, F and BF IN genes. Most codon sites of the IN genes had higher rates of synonymous substitutions (dS) indicative of a strong negative selection. Nevertheless, several codon sites mainly in the subtype B were found under positive selection. Consequently, we observed a higher genetic diversity in the B portions of the mosaics, possibly due to the more recent introduction of subtype F on top of an ongoing subtype B epidemics and a fast spread of subtype F alleles among the B population.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The Paraguay Belt in central South America is part of a larger chain of orogenic belts, including the Araguaia Belt to the northeast and potentially the Pampean Belt to the south, which are believed to mark the suture zone of the Clymene Ocean - interpreted amongst the youngest of the Gondwana amalgamation orogens. The post-orogenic Sao Vicente Granite crops out in the northern Paraguay Belt and cuts the basal unit of the deformed and metamorphosed Cuiaba Group. The age of this granite therefore provides a long sort after minimum age for orogenesis within the belt. Dating crystallisation of this important intrusion is challenging due to the presence of considerable common-Pb. However, based on LA-ICPMS dating of more than 100 zircons from three separate samples we interpret a robust crystallisation age for the Sao Vicente batholith at 518 +/- 4 Ma. This age constrains the termination of deformation within the Paraguay Belt and the final accretion of the supercontinent Gondwana. (C) 2011 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The tick-borne bacterium Rickettsia rickettsii is the aetiological agent of Brazilian spotted fever (BSF). The present study evaluated tick infestations on wild and domestic animals, and the rickettsial infection in these animals and their ticks in 7 forest areas adjacent to human communities in the Sao Paulo Metropolitan Area (SPMA). The results were compared to ecological traits of each sampled area. Two main tick species, Amblyomma aureolatum and Rhipicephalus sanguineus, were collected from dogs. The major ticks found on small mammals and birds were Ixodes loricatus and Amblyomma longirostre, respectively. Both anti-R. rickettsii antibodies and R. rickettsii-infected ticks were detected on dogs from only 2 areas in the southern part of the SPMA, which were considered to be endemic for BSF; the remaining 5 areas were considered to be non-endemic. Ecologically, the BSF-endemic areas clearly differed from the non-endemic areas by the presence of significantly more degraded forest patches in the former. The present results corroborate historical observations that have indicated that all human cases of BSF in the SPMA were contracted in the southern part of this metropolitan area. However, not all forest patches in the southern part of the SPMA were shown to be associated with BSF endemism.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Background: World population growth is projected to be concentrated in megacities, with increases in social inequality and urbanization-associated stress. Sao Paulo Metropolitan Area (SPMA) provides a forewarning of the burden of mental disorders in urban settings in developing world. The aim of this study is to estimate prevalence, severity, and treatment of recently active DSM-IV mental disorders. We examined socio-demographic correlates, aspects of urban living such as internal migration, exposure to violence, and neighborhood-level social deprivation with 12-month mental disorders. Methods and Results: A representative cross-sectional household sample of 5,037 adults was interviewed face-to-face using the WHO Composite International Diagnostic Interview (CIDI), to generate diagnoses of DSM-IV mental disorders within 12 months of interview, disorder severity, and treatment. Administrative data on neighborhood social deprivation were gathered. Multiple logistic regression was used to evaluate individual and contextual correlates of disorders, severity, and treatment. Around thirty percent of respondents reported a 12-month disorder, with an even distribution across severity levels. Anxiety disorders were the most common disorders (affecting 19.9%), followed by mood (11%), impulse-control (4.3%), and substance use (3.6%) disorders. Exposure to crime was associated with all four types of disorder. Migrants had low prevalence of all four types compared to stable residents. High urbanicity was associated with impulse-control disorders and high social deprivation with substance use disorders. Vulnerable subgroups were observed: women and migrant men living in most deprived areas. Only one-third of serious cases had received treatment in the previous year. Discussion: Adults living in Sao Paulo megacity had prevalence of mental disorders at greater levels than similar surveys conducted in other areas of the world. Integration of mental health promotion and care into the rapidly expanding Brazilian primary health system should be strengthened. This strategy might become a model for poorly resourced and highly populated developing countries.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

O trabalho apresenta algumas reflexões sobre a história da formação do acervo acadêmico dos cursos jurídicos do Brasil criados no século XIX, especificamente da Faculdade de Direito da Universidade de São Paulo. A primeira Biblioteca Pública de São Paulo, fundada em 1825, exerceu forte influência para que o Convento dos frades franciscanos recebesse a escola de direito criada por Decreto Imperial, em razão de seu fundo bibliográfico de 5.000 mil livros, preponderantemente de cunho eclesiástico, e considerável para os padrões culturais do Brasil à época. Atualmente configura-se como uma importante biblioteca jurídica acadêmica da América Latina e, ao longo da sua história tem sido uma instituição de depósito moral, isto é, recebe doações das mais diversas localidades do país, encaminhadas espontaneamente pelos autores para ter sua obra disponibilizada no acervo do primeiro e um dos mais tradicionais cursos de Direito do Brasil. Atualmente, este acervo está estimado em aproximadamente 400 mil itens, com doações de personalidades brasileiras. Outro ponto estudado refere-se ao estabelecimento de critérios para seleção de material – corpo editorial, autores de renome, relevância nos temas abordados etc. – em razão do boom editorial ocorrido na década de 1990, concomitante com o aumento de escolas de Direito no país. Chama-se à reflexão de quem atua na seara jurídica para atentar a pontos relevantes no momento da seleção para não incorrer no erro de avaliar com preconceito, modernidade, ideológico, interesse de estudo pessoal ou embasado apenas na data de publicação da obra. As ciências humanas, diferentemente de outras áreas, têm sua obsolescência mais lenta ou inexistente, decorrendo em grave erro para o Direito julgar exclusivamente pela data de publicação, o que torna premente aos profissionais bibliotecários dominarem conceitos básicos na área de atuação para que as bibliotecas sejam depositárias de material bibliográfico de qualidade.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

O trabalho avalia a intensidade e modo de utilizacao dos tratores no Projeto Bebedouro da CODEVASF, baseado nos dados fornecidos pela CAMPIB (Cooperativa Agricola Mista do Projeto de Irrigacao do Bebedouro Ltda.) e de um produtor (Fazenda Delta Agropecuaria Ltda.) da regiao. Foram analisados os dados de tres anos (1980, 1981 e 1982) de 15 tratores da CAMPIB e de dois anos (1980 e 1981) de um trator da Fazenda Delta. A maior utilizacao dos tratores no Projeto e feita para operacoes do preparo do solo (aracao e gradagem) variando de 70% a 80% das horas produtivas no caso da CAMPIB e 58% no caso da Fazenda Delta, tendo uso anual em ambos os casos na faixa de 1.000-1.400 horas por trator. As outras operacoes realizadas usando tratores sao transporte, trilhagem e sistematizacao da terra no caso da CAMPIB, e transporte e aplicacao do calcario e adubo, no caso da Fazenda Delta. A media anual dos dias de trabalho dos tratores da CAMPIB variam de 117 a 141, e a media dos dias de trabalho por mes e por unidade de trator varia de 9,7 a 11,8 dias. No projeto, alem de tratores, a travao animal e utilizada principa.lmente para operacoes de sulcamente e cobertura do adubo, portanto, o resto das operacoes e realizado manualmente. O custo de operacoes realizadas utilizando tratores varia de 15% a 46% do custo total da mecanizacao dependente das culturas, tendo a media geral do rendimento das varias operacoes (utilizando trator) 0,31 ha/h (aracao), 0,58 ha/h (gradagem), 0,55 ha/h (sulcamento, 11,7 sacos (60 kg)/h (...).

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The state of the practice in safety has advanced rapidly in recent years with the emergence of new tools and processes for improving selection of the most cost-effective safety countermeasures. However, many challenges prevent fair and objective comparisons of countermeasures applied across safety disciplines (e.g. engineering, emergency services, and behavioral measures). These countermeasures operate at different spatial scales, are funded often by different financial sources and agencies, and have associated costs and benefits that are difficult to estimate. This research proposes a methodology by which both behavioral and engineering safety investments are considered and compared in a specific local context. The methodology involves a multi-stage process that enables the analyst to select countermeasures that yield high benefits to costs, are targeted for a particular project, and that may involve costs and benefits that accrue over varying spatial and temporal scales. The methodology is illustrated using a case study from the Geary Boulevard Corridor in San Francisco, California. The case study illustrates that: 1) The methodology enables the identification and assessment of a wide range of safety investment types at the project level; 2) The nature of crash histories lend themselves to the selection of both behavioral and engineering investments, requiring cooperation across agencies; and 3) The results of the cost-benefit analysis are highly sensitive to cost and benefit assumptions, and thus listing and justification of all assumptions is required. It is recommended that a sensitivity analyses be conducted when there is large uncertainty surrounding cost and benefit assumptions.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Intercalated Archean komatiites and dacites sit above a thick footwall dacite unit in the host rock succession at the Black Swan Nickel Mine, north of Kalgoorlie in the Yilgarn Craton, Western Australia. Both lithofacies occur in units that vary in scale from laterally extensive at the scale of the mine lease to localized, thin, irregular bodies, from > 100 m thick to only centimetres thick. Some dacites are only slightly altered and deformed, and are interpreted to post-date major deformation and alteration (late porphyries). However, the majority of the dacites display evidence of deformation, especially at contacts, and metamorphism, varying from silicification and chlorite alteration at contacts to pervasive low grade regional metamorphic alteration represented by common assemblages of chlorite, sericite and albite. Texturally, the dacites vary from entirely massive and coherent to partially brecciated to totally brecciated. Strangely, some dacites are coherent at the margins and brecciated internally. Breccia textures vary from cryptically defined, to blocky, closely packed, in situ jig-saw fit textures with secondary minerals in fractures between clasts, to more apparent matrix rich textures with round clast forms, giving apparent conglomerate textures. Some clast zones have multi-coloured clasts, giving the impression of varied provenance. Strangely however, all these textural variants have gradational relationships with each other, and no bedding or depositional structures are present. This indicates that all textures have an in situ origin. The komatiites are generally altered and pervasively carbonate veined. Preservation of original textures is patchy and local, but includes coarse adcumulate, mesocumulate, orthocumulate, crescumulate-harrisite and occasionally spinifex textures. Where original contacts between komatiites and dacites are preserved intact (i.e. not sheared or overprinted by alteration), the komatiites have chilled margins, whereas the dacites do not. The margins of the dacites are commonly silicified, and inclusions of dacite occur in komatiite, even at the top contacts of komatiite units, but komatiite clasts do not occur in the dacites. The komatiites therefore were emplaced as sills into the dacites, and the intercalated relationships are interpreted as intrusive. The brecciation and alteration in the dacites are interpreted as being largely due to hydraulic fracturing and alteration induced by contact metamorphic effects and hydrothermal alteration deriving from the intrusion of komatiites into the felsic pile. The absence of autobreccia and hyaloclastite textures in the dacites suggest that they were emplaced as an earlier intrusive (sill?) complex at a high level in the crust.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The thick piles of late-Archean volcaniclastic sedimentary successions that overlie the voluminous greenstone units of the eastern Yilgarn Craton, Western Australia, record the important transition from the cessation in mafic-ultramafic volcanism to cratonisation between about 2690 and 2655 Ma. Unfortunately, an inability to clearly subdivide the superficially similar sedimentary successions and correlate them between the various geological terranes and domains of the eastern Yilgarn Craton has led to uncertainty about the timing and nature of the region's palaeogeographic and palaeotectonic evolution. Here, we present the results of some 2025 U–Pb laser-ablation-ICP-MS analyses and 323 Sensitive High-Resolution Ion Microprobe (SHRIMP) analyses of detrital zircons from 14 late-Archean felsic clastic successions of the eastern Yilgarn Craton, which have enabled correlation of clastic successions. The results of our data, together with those compiled from previous studies, show that the post-greenstone sedimentary successions include two major cycles that both commenced with voluminous pyroclastic volcanism and ended with widespread exhumation and erosion associated with granite emplacement. Cycle One commences with an influx of rapidly reworked feldspar-rich pyroclastic debris. These units, here-named the Early Black Flag Group, are dominated by a single population of detrital zircons with an average age of 2690–2680 Ma. Thick (up to 2 km) dolerite bodies, such as the Golden Mile Dolerite, intrude the upper parts of the Early Black Flag Group at about 2680 Ma. Incipient development of large granite domes during Cycle One created extensional basins predominantly near their southeastern and northwestern margins (e.g., St Ives, Wallaby, Kanowna Belle and Agnew), into which the Early Black Flag Group and overlying coarse mafic conglomerate facies of the Late Black Flag Group were deposited. The clast compositions and detrital-zircon ages of the late Black Flag Group detritus match closely the nearby and/or stratigraphically underlying successions, thus suggesting relatively local provenance. Cycle Two involved a similar progression to that observed in Cycle One, but the age and composition of the detritus were notably different. Deposition of rapidly reworked quartz-rich pyroclastic deposits dominated by a single detrital-zircon age population of 2670–2660 Ma heralded the beginning of Cycle Two. These coarse-grained quartz-rich units, are name here the Early Merougil Group. The mean ages of the detrital zircons from the Early Merougil Group match closely the age of the peak in high-Ca (quartz-rich) granite magmatism in the Yilgarn Craton and thus probably represent the surface expression of the same event. Successions of the Late Merougil Group are dominated by coarse felsic conglomerate with abundant volcanic quartz. Although the detrital zircons in these successions have a broad spread of age, the principal sub-populations have ages of about 2665 Ma and thus match closely those of the Early Merougil Group. These successions occur most commonly at the northwestern and southeastern margins of the granite batholiths and thus are interpreted to represent resedimented units dominted by the stratigraphically underlying packages of the Early Merougil Group. The Kurrawang Group is the youngest sedimentary units identified in this study and is dominated by polymictic conglomerate with clasts of banded iron formation (BIF), granite and quartzite near the base and quartz-rich sandstone units containing detrital zircons aged up to 3500 Ma near the top. These units record provenance from deeper and/or more-distal sources. We suggest here that the principal driver for the major episodes of volcanism, sedimentation and deformation associated with basin development was the progressive emplacement of large granite batholiths. This interpretation has important implication for palaeogeographic and palaeotectonic evolution of all late-Archean terranes around the world.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This research led to the discovery of one of the best preserved remnants of the Earth's surficial environment 3.47 billion years ago. These ancient volcanic and sedimentary rocks contain original minerals and textures that are rare in rocks of this age. The research concentrated on chemical analysis of volcanic rocks to differentiate secondary alteration from the primary magmatic signature. This study contributes to our understanding of melting processes and geochemical reservoirs in the early Earth, which is vital for forward modelling of Earth's geodynamic evolution.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The Archean Hollandaire volcanogenic massive sulfide deposit is a felsic–siliciclastic VMS deposit located in the Murchison Domain of the Youanmi Terrane, Yilgarn Craton, Western Australia. It is hosted in a succession of turbidites, mudstones and coherent rhyodacite sills and has been metamorphosed to upper greenschist/lower amphibolite facies and includes a pervasive S1 deformational fabric. The coherent rhyodacitic sills are interpreted as syndepositional based on geochemical similarities with well-known VMS-associated felsic rocks and similar foliations to the metasediments. We offer several explanations for the absence of textural evidence (e.g. breccias) for syn-depositional origins: 1) the subaqueous sediments were dehydrated by long-lived magmatism such that no pore-water remained to drive quench fragmentation; 2) pore-space occlusion by burial and/or, 3) alteration overprinting and obscuring of primary breccias at contact margins. Mineralisation occurs by sub-seafloor replacement of original host rocks in two ore bodies, Hollandaire Main (~125 x >500 m and ~8 m thick) and Hollandaire West (~100 x 470 m and ~5 m thick), and occurs in three main textural styles, massive sulfides, which are exclusively hosted in turbidites and mudstones, and stringer and disseminated sulfides, which are also hosted in coherent rhyodacite. Most sulfides have textures consistent with remobilisation and recrystallisation. Hydrothermal metamorphism has altered the hangingwall and footwall to similar degrees, with significant gains in Mg, Mn and K and losses in Na, Ca and Sr. Garnet and staurolite porphyryoblasts also exhibit a footprint around mineralisation, extending up to 30 m both above and below the ore zone. High precision thermal ionisation mass spectrometry of zircons extracted from the coherent rhyodacite yield an age of 2759.5 ± 0.9 Ma, which along with geochemical comparisons, places the succession within the 2760–2735 Ma Greensleeves Formation of the Polelle Group of the Murchison Supergroup. Geochemical and geochronological evidence link the coherent rhyodacite sills to the Peter Well Granodiorite pluton ~2 km to the W, which acted as the heat engine driving hydrothermal circulation during VMS mineralisation. This study highlights the importance of both: detailed physical volcanological studies from which an accurate assessment of timing relationships, particularly the possibility of intrusions dismembering ore horizons, can be made; and identifying synvolcanic plutons and other similar suites, for VMS exploration targets in the Youanmi Terrane and worldwide.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The largest Neoarchean gold deposits in the world-class St Ives Goldfield, Western Australia, occur in an area known as the Argo-Junction region (e.g. Junction, Argo and Athena). Why this region is so well endowed with large deposits compared with other parts of the St Ives Goldfield is currently unclear, because gold deposits at St Ives are hosted by a variety of lithologic units and were formed during at least three different deformational events. This paper presents an investigation into the stratigraphic architecture and evolution of the Argo-Junction region to assess its implications for gold metallogenesis. The results show that the region's stratigraphy may be subdivided into five regionally correlatable packages: mafic lavas of the Paringa Basalt; contemporaneously resedimented feldspar-rich pyroclastic debris of the Early Black Flag Group; coarse polymictic volcanic debris of the Late Black Flag Group; thick piles of mafic lavas and sub-volcanic sills of the Athena Basalt and Condenser Dolerite; and the voluminous quartz-rich sedimentary successions of the Early Merougil Group. In the Argo-Junction region, these units have an interpreted maximum thickness of at least 7,130 m, and thus represent an unusually thick accumulation of the Neoarchean volcano-sedimentary successions. It is postulated that major basin-forming structures that were active during deposition and emplacement of the voluminous successions later acted as important conduits during mineralisation. Therefore, a correlation exists between the location of the largest gold deposits in the St Ives Goldfield and the thickest parts of the stratigraphy. Recognition of this association has important implications for camp-scale exploration.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

We report sensitive high mass resolution ion microprobe, stable isotopes (SHRIMP SI) multiple sulfur isotope analyses (32S, 33S, 34S) to constrain the sources of sulfur in three Archean VMS deposits—Teutonic Bore, Bentley, and Jaguar—from the Teutonic Bore volcanic complex of the Yilgarn Craton, Western Australia, together with sedimentary pyrites from associated black shales and interpillow pyrites. The pyrites from VMS mineralization are dominated by mantle sulfur but include a small amount of slightly negative mass-independent fractionation (MIF) anomalies, whereas sulfur from the pyrites in the sedimentary rocks has pronounced positive MIF, with ∆33S values that lie between 0.19 and 6.20‰ (with one outlier at −1.62‰). The wall rocks to the mineralization include sedimentary rocks that have contributed no detectable positive MIF sulfur to the VMS deposits, which is difficult to reconcile with the leaching model for the formation of these deposits. The sulfur isotope data are best explained by mixing between sulfur derived from a magmatic-hydrothermal fluid and seawater sulfur as represented by the interpillow pyrites. The massive sulfide lens pyrites have a weighted mean ∆33S value of −0.27 ± 0.05‰ (MSWD = 1.6) nearly identical with −0.31 ± 0.08‰ (MSWD = 2.4) for pyrites from the stringer zone, which requires mixing to have occurred below the sea floor. We employed a two-component mixing model to estimate the contribution of seawater sulfur to the total sulfur budget of the two Teutonic Bore volcanic complex VMS deposits. The results are 15 to 18% for both Teutonic Bore and Bentley, much higher than the 3% obtained by Jamieson et al. (2013) for the giant Kidd Creek deposit. Similar calculations, carried out for other Neoarchean VMS deposits give value between 2% and 30%, which are similar to modern hydrothermal VMS deposits. We suggest that multiple sulfur isotope analyses may be used to predict the size of Archean VMS deposits and to provide a vector to ore deposit but further studies are needed to test these suggestions.