Tectonic history and the biogeography of the freshwater fishes from the coastal drainages of eastern Brazil: an example of faunal evolution associated with a divergent continental margin

As drenagens costeiras do leste do Brasil correspondem a áreas de grande significado biogeográfico, apresentando um alto grau de endemismo em sua fauna de peixes. Padrões filogenéticos sugerem uma relação próxima entre os rios que correm para o Atlântico a os adjacentes das terras altas do escudo cristalino. Entretanto, pouco tem sido dito sobre a dinâmica dos processos geológicos relacionados aos eventos cladogenéticos entre estas áreas. Padrões de distribuição e filogenéticos sugerem uma íntima associação com a história geológica da margem continental passiva da América do Sul, desde o Cretáceo aos dias atuais. Soerguimentos macrodômicos, rifteamento, movimentos verticais entre blocos falhados e o recuo erosivo da margem leste sul-americana são considerados como as principais forças geológicas atuando sobre a distribuição da ictiofauna de água doce nestas áreas. A atividade tectônica associada à ruptura do Gondwana e separação da América do Sul e África criou seis megadomos que são responsáveis por configurar a maior parte do atual curso das principais bacias hidrográficas do escudo cristalino. Com exceção das bacias localizadas às margens de tais megadomos, estes rios desenvolveram longos e sinuosos circuitos sobre o antigo escudo cristalino brasileiro antes de desaguarem no então recentemente aberto Oceano Atlântico. Eventos cladogenéticos iniciais entre drenagens de terras altas do escudo cristalino e tributários do Atlântico podem estar associados com processos vicariantes desta fase inicial, e alguns táxons antigos, basais, grupos-irmão de táxons muito inclusivos e de ampla distribuição são encontrados nestas bacias hidrográficas. Mais tarde, a denudação erosiva generalizada resultou em um ajuste isostático da margem leste da plataforma. Tal ajuste, concomitantemente a reativações de antigas zonas de falha, resultou em movimentos verticais entre blocos falhados, dando origem, no sudeste do Brasil, a bacias tafrogênicas. Tais bacias, como a de Taubaté, São Paulo, Curitiba e Volta Redonda, entre outras, capturaram drenagens e fauna de terras altas adjacentes. Os peixes fósseis da Formação Tremembé (Eoceno-Oligoceno da Bacia de Taubaté) exemplificam este processo. Outros sistemas tafrogênicos de idade Terciária foram também identificados em outros segmentos da margem continental Atlântica, como na Província Borborema, no NE do Brasil, com marcada influência sobre o padrão de drenagem. Ao mesmo tempo, o recuo erosivo da margem leste da plataforma capturou sucessivamente rios de planalto, os quais se tornaram tributários atlânticos, evoluindo associados aos principais sistemas de falha. A natureza continuada destes processos explica os padrões filogenéticos e de distribuição miscigenados entre os tributários atlânticos e as terras altas do escudo cristalino adjacente, especialmente na margem sudeste do continente, representados por sucessivos, cada vez menos inclusivos, grupos irmãos, associados a eventos cladogenéticos desde o final do Cretáceo ao presente.

Burial history and porosity evolution of Brazilian upper Jurassic to tertiary sandstone reservoirs

The parameter time-depth index (TDI) is applied in this study to quantify empirically the influence of burial history on sandstone porosity evolution. The TDI, expressed in kilometers per million years of age, is defined as the area in the burial history diagram enclosed by the burial curve of the reservoir and the axes of the diagram. In practice, reservoir depths during burial history are integrated at regular time intervals of 1 m.y. The calculations exclude present-day bathymetry or paleobathymetry. Sandstone reservoirs from several sedimentary basins along the Brazilian continental margin (Santos, Campos, Espírito Santo, Cumuruxatiba, Recôncavo, Sergipe, Alagoas, and Potiguar) were analyzed to investigate the evolution of porosity against TDI. These Upper Jurassic to Tertiary sandstones lie in depths of 700 to 4900 m, and are hydrocarbon charged (oil or gas). Average porosities of most of these reservoirs were obtained from core analysis, and a few porosity data were taken from well log interpretations. Detrital constituents of the sandstones are mainly quartz, feldspar, and granitic/gneissic rock fragments. Sandstones were grouped into three main reservoir types, based on composition (detrital quartz content) and grain sorting: Type I (average quartz content <50%) are very coarse grained to conglomeratic, poorly to very poorly sorted lithic arkoses. Rock fragments are mainly granitic/gneissic and coarse grained. Type II (average quartz content ranging from 50% to 70%) are fine- to coarse-grained (pebbles absent or occurring in small percentages), moderately sorted arkoses. Type III (average quartz content >80%) are fine to coarse, moderately to poorly sorted quartz arenites or subarkoses. Plots of average porosity against depth show great dispersion in porosity values; such dispersion is mostly due to differences in the reservoir burial histories. However, plotting porosity values against the TDI for individual reservoir types produces well-defined trends. The decrease in porosity is less marked in Type III reservoirs, intermediate in Type II, and faster in Type I. Such plots suggest that it is possible to make relatively accurate porosity predictions based on reservoir TDI, texture, and composition,: within the constraints of reservoir depth/age and basin tectonics analyzed in this study.

Piranha Attacks on Humans in Southeast Brazil: Epidemiology, Natural History, and Clinical Treatment, with Description of a Bite Outbreak

There are many tales describing ferocious schools of piranha attacking humans, but there are few scientific data supporting such behavior. The very few documented instances of humans attacked and eaten by piranha schools include 3 that occurred after death by other causes (eg, heart failure and drowning). These predaceous fishes, however, do occasionally injure bathers and swimmers in lakes and rivers. The characteristic profile of most injuries is a single bite per victim, generally related to the fish defending its brood. This paper describes an outbreak of piranha bites in a dammed river portion in southeast Brazil. The outbreak was caused by the speckled piranha, Serrasalmus spilopleura, a widespread species which benefits from the growing tendency of damming rivers all over Brazil. This article focuses on the epidemiological and clinical aspects of the injuries, as well as on piranha biology, to gain a better understanding of the natural history of bite outbreaks.

Inequality, institutions and progress: a debate between history and the present

Includes bibliography

On the history and political economy of small-farmer policies

Includes bibliography

A prosa de Chico Buarque em Fazenda modelo

Pós-graduação em Letras - FCLAS

The Panama Canal turns 100: history and possible future scenarios

This issue of the FAL Bulletin sets out a brief history of the Panama Canal, its construction and its social and political impact on Panama, within the context of international trade at the time. This issue also reviews the recovery of the canal by the Republic of Panama and subsequent major events, including the decision to expand the canal and the start-up of work on the expansion project.

Consciência e crítica da linguagem: Graciliano Ramos / Language awareness and criticism: Graciliano Ramos

Uma leitura atenta da ficção de Graciliano Ramos pode revelar uma forma aguda de refletir o mundo através de uma reflexão anterior sobre a própria linguagem da literatura e da sociedade. É uma leitura desse teor que se pretende mostrar, apoiada na conhecida teoria das funções da linguagem de Jakobson. Num jogo constante entre as funções fática e metalingüística, Graciliano Ramos demonstra visível consciência dos problemas de linguagem, cujo tratamento moderno aponta uma postura bastante crítica (via linguagem) perante o homem e a vida. An attentive of Graciliano Ramos’ fiction reveals a deep form of reflection on the world thorough a previous reflection on the very language of literature and society. Such a reading is here attempted based on Jakobson’s well known theory of language functions. In a constante play between the fatic and the metalinguistic function, Graciliano Ramos demonstrates a clear awareness of the problems of language, whose modern treatment points at a very critical poise (via language) before man and life.

Diversity, natural history, and geographic distribution of snakes in the Caatinga, Northeastern Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Álvaro Lins: leitor de Graciliano Ramos

Pós-graduação em Letras - FCLAS

Life history and DNA barcode of Oxyurella longicaudis (Birgei, 1910) (Cladocera, Anomopoda, Chydoridae)

Background: Cladocera is an important group of freshwater zooplankton, and the species plays an important role in energy transfer and in aquatic food webs. Oxyurella longicaudis is a Chydoridae species that has been recorded in North and South America. The aim of this study is to investigate the life cycle aspects of parthenogenetic females of O. longicaudis cultured in laboratory under controlled conditions: temperature (23 degrees C +/- 05 degrees C), photoperiod (12 h light/12 h dark), food supply, and reconstituted water.Results: Embryonic development duration (2.3 +/- 0.5 days), post-embryonic development (5.2 +/- 0.69 days), mean fecundity (two eggs female(-1) brood(-1)), total egg production (22.55 +/- 3.98 eggs), average longevity (58 days), and body growth of the species were recorded. We also report the first DNA barcode for O. longicaudis isolated in Brazil, which will allow for easy identification in future zooplankton community studies. The analysis shows a genetic divergence of around 7% between our Brazilian isolate and O. longicaudis isolates from Mexico.Conclusions: The time of embryonic and post-embryonic development of O. longicaudis was higher than that of the other species of the same family, which contributed to lower total egg production throughout its life cycle. The genetic divergence appears to be sufficient to classify the two isolates as different species.