944 resultados para upper miocene


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

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The various pull-through techniques used to measure pressure and length of the upper esophageal sphincter have not been studied in depth. Because of the importance of obtaining further information about these techniques, a group of 25 dogs was submitted to upper esophageal sphincter pressure and length measurements by three different pull-through techniques (two of the continuous type and one of the station type), each with three replications per animal, to determine possible differences among techniques. A single introduction provided reliable results, with no sequential effect of the measurements or of any one technique on resting pressure. However, each technique yielded different sphincter lengths, higher values being obtained when the continuous techniques were used.

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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.

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This paper presents optical and electrical measurements on plasma generated by DC excited glow discharges in mixtures composed of 95% N2, 4.8% CH4 and 0.2% H2O at pressures varying from 1.064 mbar to 4.0 mbar. The discharges simulate the chemical reactions that may occur in Titan's atmosphere in the presence of meteorites and ice debris coming from Saturn's systems, assisted by cosmic rays and high energy charged particles. The results obtained from actinometric optical emission spectroscopy, combined with the results from a pulsed Langmuir probe, show that chemical species CH, CN, NH and OH are important precursors in the synthesis of the final solid products and that the chemical kinetics is essentially driven by electronic collision processes. It is shown that the presence of water is sufficient to produce complex solid products whose components are important in prebiotic compound synthesis. © 1998 Elsevier Science Ltd. All rights reserved.

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Monthly samples were taken from April 1992 to March 1993 of fish assemblages present in six permanent lagoons and four ponds, fragmented from them during the drought period and during the terminal phases of desiccation, to evaluate changes in their diversity, abundance and dominance. Their relationships with hydrological and environment conditions were examined. A total of 63 fish species were identified. Species composition and abiotic factors were heterogeneous among the different water bodies. The proportion of piscivores and oxygen concentration were the determining factors for structuring the assemblages. The impact of piscivory upon fish diversity was neutral at the beginning and negative at the end of the dry season. In the terminal phase of desiccation, diversity was higher in ponds that contained a moderate proportion of piscivores than in these containing a higher proportion.

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Bryconamericus turiuba, new species, is described from the upper Rio Paraná system in Brazil. It differs from all congeners in the following combination of characters: 15-20 branched anal-fin rays; four or five scales in a transverse series from the dorsal-fin origin to the lateral line; shallow body (depth 23.6-30.6% of SL); 37-43 perforated lateral line scales; first, third, and fifth or, more rarely, first and fourth outer premaxillary tricuspid teeth projecting anteriorly; two to five tricuspid to pentacuspid maxillary teeth; dentary with three or four tricuspid or pentacuspid large teeth, followed by five to seven smaller conical to tricuspid teeth; a conspicuous dark, vertically elongate humeral spot, extending to below the lateral line; a dark dorsal stripe extending from the supraoccipital spine to the caudal peduncle with a gap at the adipose-fin base; caudal-fin lobes without conspicuous markings, uniformly pigmented along rays; mature males lacking hooks on the pelvic- and anal-fin rays. The new species is compared with the Bryconamericus species described from the basins of the Rio Paraná, Rio Paraguay, Rio São Francisco, and coastal Brazilian rivers. © 2005 by the American Society of Ichthyologists and Herpetologists.

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With the exception of the cleft lip, developmental defects (DD) of the lip are rare. The upper lip originates from the ectomesenchyme and is formed by the merging of the nasal medial and lateral processes with the maxillary process. Disturbances during this formation period can cause DD with functional and/or esthetic repercussions. We present a case of DD of the upper lip in a patient with a history of progressive growth of the left lateral portion of the upper lip that occurred from the time of birth until the age of 22 years. Clinical examination revealed hypertrophy of the area from the left philtral columns to the left commissure of the lip, extending the portion of the surface mucosa creating a flaccid and asymptomatic tissue mass. All other buccal structures appeared to be within normal limits and without any evidence of defects or deformities. In the surgical planning we decided to carry out corrective surgery in two phases. The first phase accomplished a conservative excision of the total abnormal labial tissue mass with a CO2 laser radiation (5 W in continuous mode, bunch diameter φ = 0.6 mm with a power density of 768 W/cm2 and fluency of 0.231 J/cm2) being careful to preserve the vermilion portion of the lip. Postsurgical clinical evaluations were done every three days until the skin sutures were removed and then every seven days until two months post surgery. While the entire mass of excessive tissue could not be completely removed, the removal of the excessive mucosal tissue produced a very good outcome relative to lip function, with a good esthetic result without scarring, and good tissue mobility. The results showed that the CO2 laser is an extremely useful instrument that can provide excellent control of the surgical field and allow for healing that produces excellent functional and esthetic results. © 2005 Taylor & Francis.

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Alluvial paleosoil horizons from the 3 to 4 m high banks of the Paraná River were used to reconstruct the palaeoenvironmental history and palaeohydrological regime of the river. The bank consists of a Middle to Late Holocene sequence of sandy to silty clay layers of overbank deposits. The paleosoil horizon is located to a depth of 1.95 m from the top of the bank and is recognized as a guide horizon throughout the floodplain of the Upper Paraná River floodplain. Analyses of organic matter (δ13C and humic/fulvic acids), palynology (pollen and charcoal fragments), magnetic susceptibility, micromorphology, x-ray diffraction and 14C dating were conducted for samples from two representative profiles of the study area. Two phases were characterized in the history of the river: 1) An older phase, of stability in fluvial hydrology (stasis) with low frequency of floods, which produced conditions for soil development (14C 1700 ± 70 yr. BP). At this period, the predominance of herbaceous vegetation (determinated by pollen and δ13C analyses) suggests a climate less humid than the present one, and 2) A second phase, when climate changed to the present conditions of humidity (annual rain fall of 1600 rum) and characterized by the predominance of C3 plants. Under this new hydrological regime, the river developed an agradational floodplain, with a depositional sedimentary rate of 1.2 mm.y-1. © 2006 Gebrüder Borntraeger.

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A new Hypoptopomatinae, Corumbataia britskii, is described based on specimens recently collected in a tributary of the upper Rio Paraná basin, Mato Grosso do Sul State, Brazil. Corumbataia britskii differs from its congeners by having a more depressed head profile (vs. a more rounded head profile in C. cuestae and C. tocantinensis), by having a more developed and conspicuous tuft of enlarged odontodes on the tip of the supraoccipital (vs. its reduced condition found in C. cuestae and C. tocantinensis), and by heaving a partially enclosed arrector fossae (vs. an almost completely enclosed arrector fossae in C. cuestae and C. tocantinensis). Copyright © 2007 Magnolia Press.

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Oligosarcus perdido, a new species of freshwater fish from Serra da Bodoquena, upper Rio Paraguai basin, Brazil, is described. The new species is distinguished from congeners by the number of lateral-line scales, number of scales around the caudal peduncle, and osteological characters. The osteology of this new species is also documented by stereomicroscopic photography of cleared and stained specimens. Ecological notes based on direct observation by scuba diving in the field are also provided. Copyright © 2007 Magnolia Press.

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Purpose: To determine the prevalence of trachoma in Sao Gabriel da Cachoeira (SGC), the only urban community of the upper Rio Negro Basin of the Amazon state in Brazil, near the Colombian border, and to investigate the risk factors associated with the active forms of the disease. Methods: A total of 1702 people (440 children up to 9 years and 1069 adults aged 15 years and above) were examined. The sample was selected from a probabilistic household sampling procedure based on census data and a previous study of trachoma prevalence in Sao Gabriel da Cachoeira. A two-stage probabilistic household cluster sample was drawn. Household units were randomly selected within each cluster. A variety of socioeconomic and hygiene variables were studied in order to determine the risk factors for active trachoma in a household. Results: The total prevalence of trachoma was 8.9%. Prevalence of active trachoma (TF and/or TI) in children aged 1-9 years was 11.1% and trachomatous trichiasis in adults aged 15 years and above was 0.19%. Trachomatous scarring reached a peak of 22.4% for subjects between 50 to 60 years of age. Corneal opacity occurred in subjects aged 50 years and older with a prevalence of 2.0%. No sex effect was found on the overall prevalence of trachoma in SGC. Risk factors associated with active trachoma were mainly related to poor socioeconomic indicators. Conclusions: Despite the ubiquitous presence of water, the analysis of the risk factors associated with the active forms of the disease supports the idea that a low personal standard of hygiene and not water availability per se, is the key factor associated with trachoma. Copyright © 2008 Informa Healthcare USA, Inc.

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Calcareous Albian-Cenomanian strata in the Potiguar basin yield a number of microfossils, among which are calcareous algae (Dasycladales and Corallinales). This data, together with an inventory of previous discoveries, enabled the discussion of their biogeography. These benthic organisms probably came from the early Central Atlantic Ocean through its northwestern neck between Africa and South America and thus reached the early South Atlantic platforms.

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Includes bibliography