Length structure of fishes from a protected area in the State of São Paulo, Southeastern Brazil

The aim of this work was to study the length distribution of some fish species from the Protected Area of São Pedro and Analândia, State of São Paulo, Southeastern Brazil. Length distributions were correlated to environmental conditions at each sample site. For the most abundant species, length structure was compared among the streams of each basin and between basins. Differences in length structure were related to differences in growth, habitats, and even population.

Revision of the South American freshwater genus Plagioscion (Teleostei, Perciformes, Sciaenidae)

The South American freshwater sciaenid genus Plagioscion is reviewed. Five of the 15 nominal species assigned to the genus are considered to be valid: Plagioscion squamosissimus, widely distributed in Atlantic drainages east of the Andes; P. auratus from the Río Orinoco and Río Amazonas basins; P. magdalenae from the Río Magdalena and Río Amazonas basins; P. ternetzi from the lower Río Paraná, Río Paraguay and Rio Uruguay basins; and P. montei from the Río Amazonas basin. Copyright © 2005 Magnolia Press.

Analysis of susceptibility profile of Pseudomonas spp. and prevalence of bacterial samples from the surfaces of dental consulting-rooms

The aim of this research was to evaluate the susceptibility profile of Pseudomonas spp. and the prevalence of bacterial samples isolated from horizontal surfaces surrounding wash-basins used by dentists in several adjoined consulting-rooms, at points next to and at a distance from the basin, before and after surgical procedures. Our results showed a high percentage of Gram-positive cocci and Gram-negative bacilli; 34.66% were Staphylococcus spp. and 30.12% were non-fermentative Gram-negative bacilli among which Pseudomonas spp. (40.90%) was the commonest genus. Analysis of the susceptibility profile of Pseudomonas spp. isolates by determining the minimal inhibitory concentration (MIC) of 14 antibiotics showed a great variation among the strains and high rates of resistance to cefazolin, ceftazidime and aztreonan. Of the 14 antibiotics tested, 59.03% were found to be active against all the environmental isolates. Strains were resistant to aztreonan (62.82%), while susceptibility to third generation cephalosporins was variable.

Africanized honeybees: Biological characteristics, urban nesting behavior and accidents caused in Brazilian cities (Hymenoptera: Apidae)

In 1956 African honeybee queens (Apis mellifera scutellata) were imported from South Africa and Tanzania to Brazil, as part of a government project to increase Brazilian honey production. The European honeybees existing in that country had not adapted well to the tropical conditions and consequently, had a low productivity. The newly introduced bee was known to produce substantially more honey than the other subspecies, but was also famous for its great aggressiveness and quicker attack of intruders with less disturbance. Hoping to create a new hybrid bee that would be both docile and productive, the scientist Warwick Estevam Kerr tried to cross the African and the European subspecies under controlled conditions. However, an accident resulted in the escape of 26 swarms into the Brazilian countryside, where their queens mated with drones of the European resident honeybees. The poly-hybrid bees resulting from these crossings expressed scutellata-like reproductive, foraging, and defensive behaviors and, for this reason, were called Africanized honeybees. They spread rapidly from the introduction area of the African honeybees (near Rio Claro, São Paulo state) to as far south as mid-Argentina and to the north of Texas, also settling in Arizona, New Mexico, California and Nevada, due to their high adaptability to variable ecological conditions. In spite of a few undesirable behaviors, these bees have been invoking larger economic interest because they produce much more honey, have good resistance to diseases and are excellent pollinators. In Brazil, because people frequently disturb the environment, the occupation of urban refuges by Africanized honeybees has been increasing in the last years. The concern with accidents is generally associated with the high swarming frequency recorded during the year and the variety of shelters available in urban areas. This paper deals with the biological characteristics of the Africanized honeybees, their nesting behavior in urban environments, and accidents caused by these bees in Brazilian cities.

Some reflections on the future of the water quality of the corumbataí River basin, São Paulo state, Brazil

The waters of Corumbataí River in the middle and eastern part of São Paulo State, Brazil, are extensively used for human consumption; their water quality has been modified mainly due to increasing pressure caused by population growth, accompanied by a more accentuated industrial development for the whole São Paulo State in the early 1970s. The Corumbataí River basin has, over time, received significant emissions of municipal waste products and discharges of wastewater, sludge, sewage, sanitary and industrial effluents, but the first effluent treatment plant at Rio Claro city was only inaugurated at the end of the 1990s. Data on river water quality from two widely spaced locations in the Corumbataí River basin are reported in this paper; they indicate the need for continuous initiatives and efforts by decision makers in order to improve and preserve the water quality in the basin for the 21st century. Copyright © 2007 IAHS Press.

The first Triassic lungfish from South America (Santa Maria Formation, Paraná Basin) and its bearing on geological correlations within Pangaea

The Triassic fish faunas of the Southern Hemisphere are only known from a few sedimentary basins and the most productive sites are those from the Karoo Supergroup, in South Africa and the Sydney Basin of Australia. A single lungfish tooth plate ascribed to Ptychoceratodus cf. philippsi was recovered from Late Triassic (Carnian) red beds of southern Brazil and is described herein. This find extends to South America the palaeogeographic distribution of the genus, which occurs in the Early Triassic of Australia and South Africa and the Middle/Late Triassic of Europe and Late Triassic of Madagascar and India. The presence of this dipnoan solely in the uppermost part of the Santa Maria Formation suggests that the migration of Ptychoceratodus towards the Paraná Basin began not before the late Induan/early Olenekian (late Early Triassic). At that time, more humid (monsoonal) conditions prevailed in what is now southern Brazil, compared to semi-arid/desert conditions that dominated the Late Permian and possibly the earliest Early Triassic (the latter presumably not represented in the Paraná Basin). © The Geological Society of London 2008.

Análise das condições hidrológicas em bacias hidrográficas com differentes uso e ocupação do solo

The analysis of the physical medium in hydrographic basins requires knowledge of the processes involved and characteristics of variables at different geographic scales. Considering the principle that the micro-basins can be categorized, they are then considered territorial units of ideal work for the analysis of hydrologic conditions. The objective of this work was to compare water resources of four hydrographic basins' with different land use and occupation. Five sampling points along the drainage network of hydrographic basins of first order of magnitude and a sampling point in the river mouth of M1 and M4 micro-basins were established. The water collections occurred at monthly intervals from August, 2006 to August, 2007. Temperature (°C), turbidity (NTU), odor, pH, electric conductivity (μS cm-1), dissolved oxygen (mg/L), total dissolved solids (ppm) and total phosphorous (mg/L) were the variables evaluated in the study. The highest variability of the parameters was found in hydrographic basins M2 and M3. The characterization of the hydrologic conditions of the hydrographic micro-basins indicated that agricultural activities, including cultural practices of anthropic activities affect water resources.

Evolução da margem atlântica equatorial do Brasil: Três fases distensivas

The extension of the Pangaea started in the Upper Triassic and evolved to uplifts, magmatism and development a triple junction during the Mesozoic, and opening the Central Atlantic Ocean. The Brazilian Equatorial Atlantic margin was formed in three Mesozoic extensional events. The first event is recorded by the Calçoene Graben of the Foz do Amazonas Basin. The second event started in the Valangian and is recognized by the enlargement of the Foz do Amazonas Basin, formation of the Marajó and Grajaú basins, and the Gurupi Graben System. The third event commenced in the Albian related to northwestward progression of the rift system, which enlarged the Foz do Amazonas and formed the Potiguar, Ceará, Barreirinhas and Pará-Maranhão basins. At the end of the Lower Cretaceous the movements attenuated in the Marajó Basin and Gurupi Graben System; the extension concentrated in the Foz do Amazonas, Pará-Maranhão and Barreirinhas basins, and evolved to continental rupture of northern South America and western Africa opening of the Equatorial Atlantic Ocean.

Dynamics of a piecewise-linear oscillator with limited power supply

We discuss dynamics of a vibro-impact system consisting of a cart with an piecewise-linear restoring force, which vibrates under driving by a source with limited power supply. From the point of view of dynamical systems, vibro-impact systems exhibit a rich variety of phenomena, particularly chaotic motion. In our analyzes, we use bifurcation diagrams, basins of attractions, identifying several non-linear phenomena, such as chaotic regimes, crises, intermittent mechanisms, and coexistence of attractors with complex basins of attraction. © 2009 by ASME.

Optimized dynamic response of parallel operation of two single phase inverters based on evolutionary theory

In this work it is proposed an optimized dynamic response of parallel operation of two single-phase inverters with no control communication. The optimization aims the tuning of the slopes of P-ω and Q-V curves so that the system is stable, damped and minimum settling time. The slopes are tuned using an algorithm based on evolutionary theory. Simulation and experimental results are presented to prove the feasibility of the proposed approach. © 2010 IEEE.

The Mexican maquila industry and the environment: an overview of the issues

Includes bibliography

Condiciones generales de competencia en Panamá

Incluye Bibliografía

Water management at the river basin level: challenges in Latin America

Includes bibliography

Evolução do rifteamento e paleogeografia da margem Atlântica Equatorial do Brasil: Triássico ao Holoceno

The Equatorial Atlantic Margin evolved from three rift systems recorded by a complex set of sedimentary basins developed since Upper Triassic to the Lower Cretaceous (Albian). The first rift system formed Foz do Amazonas Basin in Upper Triassic; the second phase formed Marajó Basin in Berriasian, a new rift in Foz do Amazonas Basin in Valanginian and Bragança-Viseu, Ilha Nova, São Luís e Barreirinhas basins in Aptian; the third phase formed Barreirinhas and Pará- Maranhão basins and a new rifting in the Foz do Amazonas Basin between the Aptian and Albian and evolved to continental break up. The main paleostress field during rift evolution was NE-SW and after the continental break up took the E-W direction, from the development of transform zones in the oceanic crust. From Miocene, South America was subjected to intraplate tectonics, which resulted in formation of E-W transcurrent faults that generated transtensive and transpressive segments that formed sedimentary basins and hills, resulting in changes in the drainage network. In Quaternary the landscape was modified by the last ice age that changed the sea level; the coastal drainage network was drowning resulting in the formation of the current line coast.

Análise multivariada aplicada em bacias hidrográficas no município de Botucatu-SP

As imagens aerofotogramétricas de uma região registram os vários aspectos da paisagem, destacando a cobertura vegetal, a rede de drenagem e principalmente o relevo do terreno conjunto que caracterizam unidades morfométricas denominadas bacias hidrográficas. Neste trabalho aplicaram-se técnicas fotointerpretativas e estatística multivariada a variáveis do relevo, medidas em bacias hidrográficas de terceira ordem de ramificação pertencentes à bacia do rio Tiête no município de Botucatu-SP, com o objetivo de agrupar bacias segundo graus de similaridade, bem como inferir sobre a representatividade da distribuição espacial dos agrupamentos em relação ao Mapa Pedológico do Estado de São Paulo, da Embrapa de 1999. Foram utilizadas fotografias aéreas verticais, escala nominal aproximada 1:30000, (2005), cartas planialtimétricas escala 1:50000 e Mapa Pedológico do Estado de São Paulo. Foram estudadas 06 bacias hidrográficas de 3aordem de ramificação, situada na região fisiográfica denominada frente da cuesta abrangendo as unidades de solo Neossolos Litólicos (RL) e Latossolos Vermelhos distrófico (LVdf), sendo esta última predominante na área de estudo. O conjunto de variáveis de relevo mostrou-se eficiente no agrupamento das bacias conforme as unidades de solos ocorrentes, concordando com as unidades identificadas no Mapa Pedológico.