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Após 1989, introduzimos algumas alterações no tratamento cirúrgico dos aneurismas e dissecções da aorta, em nosso Serviço, entre elas maior rapidez no diagnóstico, uso de parada circulatória, hipotermia profunda, parada circulatória total, monitorização hemodinâmica, controle dos distúrbios de coagulação, controle da pressão liquórica, implantação das artérias intercostais. Entre janeiro de 1980 e julho de 1994, 520 pacientes foram submetidos a tratamento cirúrgico de aneurismas ou dissecções da aorta, de forma consecutiva e não selecionados. Os pacientes foram divididos em três grupos, de acordo com o diagnóstico: ? Aneurisma de aorta ascendente (AAAS) ? Aneurisma de arco aórtico (AAAO) ? Dissecção aguda da aorta tipos I e II (DAAO I e II) Nos três grupos, a mortalidade foi significativamente inferior para pacientes operados no período após 1989. Variáveis preditivas de mortalidade para AAAS foram: complicações pulmonares (p = 0,0210), renais (p = 0,0310), neurológicas (p < 0,0001). Para DAAO I e II, a hipertensão arterial (p < 0,0001), complicações cardíacas (p < 0,0001), neurológicas (p < 0,0001), renais (p < 0,0001) e a rotura (p < 0,0001) foram preditivas de óbito, e para AAAO foram as variáveis: idade (p = 0,0001) e complicações renais (p = 0,0015). Os autores concluem que as modificações introduzidas no método de tratamento cirúrgico dos aneurismas e dissecções da aorta contribuíram significativamente para a melhora dos resultados.

Infrared spectroscopy may be used to measure the carbonate content of apatite at high temperature. Researchers compared the carbonate content of apatites from three sources. Samples were from carbonatite, metasomatic rocks and from alkaline silicate rocks from the Jacupiranga alkaline complex. The highest carbonate levels were from the metasomatic rocks, where carbonate was about 0.6 to 1.0% by weight of the apatite. Researchers then synthesized apatite in the presence of various carbon and carbonate concentrations. Carbonate in apatite may be dependent on carbon speciation.

The development of analytical tools to determine the origin of fishes is useful to better understand patterns of habitat use and to monitor, manage, and control fisheries, including certification of food origin. The application of isotopic analyses to study calcified structures of fishes (scales, vertebrae, and otoliths) may provide robust information about the fish geographic origin and environmental living conditions. In this study, we used Sr and C isotopic markers recorded in otoliths of wild and farmed commercialized pirarucu (Arapaima spp.) to evaluate their prediction potential to trace the fishes origin. Wild and farmed fish specimens, as well as food used for feeding pirarucu in captivity, were collected from different sites. Isotope composition of otoliths performed by isotope-ratio mass spectrometry (IRMS; δ13C) and femtosecond laser ablation multi-collector inductively coupled plasma mass spectrometry (LAfs-MC-ICPMS; 87Sr/86Sr) were compared to the isotopic composition of water and of the food given to the fishes in the farms. Wild fish specimens that lived in environments with the largest fluctuation of river water Sr isotope ratios over time presented the largest Sr isotope variations in otoliths. A quadratic discriminant analysis on otolith isotopic composition provided 58 % of correct classification for fish production (wild and farmed) and 76 % of correct classification for the fish region. Classification accuracy for region varied between 100 % and 29 % for the Madeira and the Lower Amazon fishes, respectively. Overall, this preliminary trial is not yet fully developed to be applied as a commercial traceability tool. However, given the importance of Arapaima spp. for food security and the generation of economic resources for millions of people in the Amazon basin, further analyses are needed to increase the discrimination performance of these biogeographical tags. [ABSTRACT FROM AUTHOR]

In the Amazon, migratory catfishes of the genus Brachyplatystoma are apex predators that are important for fisheries and conservation. The life cycle of Brachyplatystoma platynemum Boulenger, 1898 is poorly known, although it has been hypothesized to be very similar to that of Brachyplatystoma rousseauxii Castelnau, 1855, which uses the entire length of the Amazon basin to complete its life cycle (from the Andes to the estuary). This study provides the first data on the migratory patterns of B. platynemum at the individual level using otolith microchemistry.In total, 94 individuals were sampled close to major breeding areas in the Amazon basin (78 fish from the middle and upper Madeira River and 14 fish from the upper Amazon), and their lifetime movements were assessed by measuring variations in 87Sr/86Sr along transverse sections of their otoliths (ear stones), using laser ablation multi‐collector mass spectrometry (LA‐MC‐ICP‐MS).The migrations of B. platynemum are not as extensive as those of B. rousseauxii, and do not involve natal homing. Furthermore, the estuary is not a nursery area, at least for fish hatched in the Madeira. Nevertheless, B. platynemum migrates several thousand kilometres within the Amazon basin, with transboundary displacements between at least Bolivia, Brazil, and Peru.Current and planned hydroelectric development in the Amazon basin will severely disrupt both migration and access to breeding grounds, ultimately affecting the recruitment and population dynamics of these apex predators.The conservation of B. platynemum is crucial for the stability of the Amazonian aquatic food webs. This requires building effective fish passage on the two existing Madeira dams and considering alternative options to the large‐scale hydropower development in the Amazon basin. [ABSTRACT FROM AUTHOR]

The development of analytical tools to determine the origin of fish is useful to better understand patterns of habitat use and to monitor, manage and control fisheries, including certification of food origin. The application of isotopic procedures to study fish calcified structures (scales, vertebrae, and otoliths) may provide robust information about the fish geographic origin and environmental living conditions. In this study, we used Sr and C isotopic markers recorded in otoliths of wild and farmed commercialized pirarucu (Arapaima spp.) to evaluate their prediction potential to trace the fish origin. Wild and farm fish specimens, as well as food used for feeding pirarucu in captivity, were collected from different sites. Isotope analyses of otoliths performed by IRMS (δ13C) and LAfs-MC-ICPMS (87Sr/86Sr) were compared to the isotopic composition of water and of the food given to the fish in the farms. Wild fish specimens that lived in environments with the largest fluctuation of river water Sr isotope ratios over time presented the largest Sr isotope variations in otoliths. A quadratic discriminant analysis on otolith isotopic composition provided 58% of correct classification for fish production (wild and farmed) and 76% of correct classification for the fish region. Classification accuracy for region varied between 100% and 29% for the Madeira and the lower Amazon fishes, respectively. Overall, this preliminary trial is not yet fully satisfying to be applied as a commercial traceability tool. However, given the importance of Arapaima spp. for food security and the generation of economic resources for millions of people in the Amazon basin, further analyses are needed to increase the discrimination performance of these biogeographical tags. [ABSTRACT FROM AUTHOR]

We report the results of a detailed study of dissolved Sr isotopes in the Solimões and Beni-Madeira Rivers of the Amazon basin. This study developed data collected over 8 years indicating large spatial and temporal variations in dissolved Sr isotopes among the rivers of the Amazon basin. The large 87Sr/86Sr variations were found to be correlated with the geology of the source areas of the suspended sediments. The Beni-Madeira River displays a high average 87Sr/86Sr ratio and large 87Sr/86Sr fluctuations during the hydrological cycle. This large average value and fluctuations were related to the presence of Precambrian rocks and Ordovician sediments in the source area of the suspended sediment of the river. In contrast, the Solimões River displays a narrow range of Sr isotope ratio variations and an average value close to 0.709. This river drains mostly Phanerozoic rocks of northern Peru and Ecuador that are characterized by low Sr isotope ratios. The isotopic fluctuations in the Beni-Madeira River were observed to propagate downstream at least as far as Óbidos. This signal is characterized by an inverse relationship between the concentration of elemental Sr and its isotopic ratios. We further demonstrate that the Sr isotopic composition and content in the Beni-Madeira River is controlled by suspended sediments derived from the Andes. Despite draining areas underlain by Precambrian rocks and having high 87Sr/86Sr ratios, such rivers as the Negro and Tapajós play a minor role in the total Sr budget of the Amazon basin. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: Mass-independent sulfur isotope fractionation (MIF) has been observed in rocks of the geological record older than about 2.45Ga, a characteristic which is thought to be related to processes in the Neoarchean atmosphere. Samples recording a MIF effect therefore have to contain sulfur of the exogenic sulfur cycle, while endogenic sulfur should not show this effect. The sulfides analysed from six Brazilian deposits represent either exogenic or endogenic sulfur sources, with supposed ages ranging from about 1.9 to 2.7Ga. Sulfur isotopes were analysed by in‐situ laser ablation MC-ICP-MS. A range of experiments were conducted using international and in-house isotope standards, which were run under various conditions and set-ups. These include the reference materials IAEA-S1, IAEA-S3, NBS123 (sphalerite), NBS127 (barite), and in-house standards BSB-py (pyrite) and BSB-cpy (chalcopyrite). During six days of analysis, an internal precision of sulfide analyses of 0.10–0.15‰ (1s) for δ 34S and 0.40–0.60‰ (1s) for δ 33S, and an accuracy of ~0.30‰ for δ 34S and δ 33S was achieved. The standard measurements define a δ 33S/δ 34S relationship of δ 33S=0.513* δ 34S+0.149, with R²=0.9997, which is close to the theoretical relationship for mass-dependent fractionation. The by far best analytical errors were obtained for natural pyrite, reaching a within-run precision of about 0.05–0.15‰ for δ 34S (1s), and 0.10–0.15‰ (1s) for δ 33S determinations. Including all precision and accuracy data, we arrive at the following 1s error limits to which sulfur isotope analyses for MIF studies obtained with this method are reliable: 0.32, 0.34 and 0.46‰ for pyrite (δ 34S, δ 33S and Δ33S determinations, respectively), 0.34, 0.42 and 0.54‰ for pyrrhotite, and 0.34, 0.50 and 0.58‰ for chalcopyrite. Pyrites and pyrrhotites from 2200Ma old sediments and volcanics associated with the Pilar greenstone belt, Goiás, have δ 34S from −15.0 to +2.0‰, and δ 33S from −8.0 to +1.0‰, with Δ33S being slightly but not significantly positive. Pyrites from supposed ca. 2060Ma old clastic sediments of the Águas Claras Formation (Carajás, Pará), have δ 34S=9.5–12.5‰ and δ 33S=5.0–6.5‰ with Δ33S close to zero. Chalcopyrites from the Salobo and Sequerinha sulfide deposits, also Carajás, are genetically related to 2570Ma old A-type alkaline granites with endogenic sources. They have δ 34S=1.6–2.9‰ and δ 33S=1.0–1.5‰, and δ 34S=0.2–0.9‰ and δ 33S=0.65‰, respectively, with Δ33S ranging from −0.15 to 0.56. The only Δ33S values of this study which clearly suggest sulfur isotope MIF come from the mineralized banded iron-formations of the Quadrilátero Ferrífero, Minas Gerais. Pyrites from the Mina de Cuiabá deposit (2700Ma) have δ 34S=3.8–5.1‰ and δ 33S=2.9–4.8‰ with Δ33S=0.9–2.2‰, while pyrites and chalcopyrites from São Bento (2720Ma) have δ 34S=1.6–3.2‰ and δ 33S=1.5–2.8‰ with Δ33S=0.2–1.5‰. The sulfides represent an epigenetic mineralization, derived from supracrustal rocks making part of an exogenic sulfur cycle. The study shows, that in-situ laser ablation ICP-MS is sufficiently sensitive for detecting MIF effects in Neoarchean rocks. Whether or not such samples show MIF-related Δ33S values depends on the age and provenance of the sulfur. [Copyright &y& Elsevier]

Calcified structures such as otoliths and scales grow continuously throughout the lifetime of fishes. The geochemical variations present in these biogenic structures are particularly relevant for studying fish migration and origin. In order to investigate the potential of the (87)Sr/(86)Sr ratio as a precise biogeochemical tag in Amazonian fishes, we compared this ratio between the water and fish otoliths and scales of two commercial fish species, Hoplias malabaricus and Schizodon fasciatus, from three major drainage basins of the Amazon: the Madeira, Solimões, and Tapajós rivers, displaying contrasted (87)Sr/(86)Sr ratios. A comparison of the (87)Sr/(86)Sr ratios between the otoliths and scales of the same individuals revealed similar values and were very close to the Sr isotopic composition of the local river where they were captured. This indicates, first, the absence of Sr isotopic fractionation during biological uptake and incorporation into calcified structures and, second, that scales may represent an interesting nonlethal alternative for (87)Sr/(86)Sr ratio measurements in comparison to otoliths. Considering the wide range of (87)Sr/(86)Sr variations that exist across Amazonian rivers, we used variations of (87)Sr/(86)Sr to discriminate fish origin at the basin level, as well as at the sub-basin level between the river and savannah lakes of the Beni River (Madeira basin).