995 resultados para PARAGUAY BELT


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The different types of Archean gold deposits in the Manica greenstone belt of western Mozambique are briefely describcd in the context of their geological setting. Particular attention is devoted to the mineralogy, petrology, geological controls, refractoriness to treatment and prospection of these gold deposits. The genesis of gold was stratigraphically controled, but structural and metamorphic events related to the intrusion of late granites have concentrated and relocated the gold in different geological environments. The possibility of additional gold occurences in different rocks sequences is discussed as well as possible guidelines for future research and development.

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(l) The Pacific basin (Pacific area) may be regarded as moving eastwards like a double zip fastener relative to the continents and their respective plates (Pangaea area): opening in the East and closing in the West. This movement is tracked by a continuous mountain belt, the collision ages of which increase westwards. (2) The relative movements between the Pacific area and the Pangaea area in the W-E/E-W direction are generated by tidal forces (principle of hypocycloid gearing), whereby the lower mantle and the Pacific basin or area (Pacific crust = roof of the lower mantle?) rotate somewhat faster eastwards around the Earth's spin axis relative to the upper mantle/crust system with the continents and their respective plates (Pangaea area) (differential rotation). (3) These relative West to East/East to West displacements produce a perpetually existing sequence of distinct styles of opening and closing ocean basins, exemplified by the present East to West arrangement of ocean basins around the globe (Oceanic or Wilson Cycle: Rift/Red Sea style; Atlantic style; Mediterranean/Caribbean style as eastwards propagating tongue of the Pacific basin; Pacific style; Collision/Himalayas style). This sequence of ocean styles, of which the Pacific ocean is a part, moves eastwards with the lower mantle relative to the continents and the upper-mantle/crust of the Pangaea area. (4) Similarly, the collisional mountain belt extending westwards from the equator to the West of the Pacific and representing a chronological sequence of collision zones (sequential collisions) in the wake of the passing of the Pacific basin double zip fastener, may also be described as recording the history of oceans and their continental margins in the form of successive Wilson Cycles. (5) Every 200 to 250 m.y. the Pacific basin double zip fastener, the sequence of ocean styles of the Wilson Cycle and the eastwards growing collisional mountain belt in their wake complete one lap around the Earth. Two East drift lappings of 400 to 500 m.y. produce a two-lap collisional mountain belt spiral around a supercontinent in one hemisphere (North or South Pangaea). The Earth's history is subdivided into alternating North Pangaea growth/South Pangaea breakup eras and South Pangaea growth/North Pangaea breakup eras. Older North and South Pangaeas and their collisional mountain belt spirals may be reconstructed by rotating back the continents and orogenic fragments of a broken spiral (e.g. South Pangaea, Gondwana) to their previous Pangaea growth era orientations. In the resulting collisional mountain belt spiral, pieced together from orogenic segments and fragments, the collision ages have to increase successively towards the West. (6) With its current western margin orientated in a West-East direction North America must have collided during the Late Cretaceous Laramide orogeny with the northern margin of South America (Caribbean Andes) at the equator to the West of the Late Mesozoic Pacific. During post-Laramide times it must have rotated clockwise into its present orientation. The eastern margin of North America has never been attached to the western margin of North Africa but only to the western margin of Europe. (7) Due to migration eastwards of the sequence of ocean styles of the Wilson Cycle, relative to a distinct plate tectonic setting of an ocean, a continent or continental margin, a future or later evolutionary style at the Earth's surface is always depicted in a setting simultaneously developed further to the West and a past or earlier style in a setting simultaneously occurring further to the East. In consequence, ahigh probability exists that up to the Early Tertiary, Greenland (the ArabiaofSouth America?) occupied a plate tectonic setting which is comparable to the current setting of Arabia (the Greenland of Africa?). The Late Cretaceous/Early Tertiary Eureka collision zone (Eureka orogeny) at the northern margin of the Greenland Plate and on some of the Canadian Arctic Islands is comparable with the Middle to Late Tertiary Taurus-Bitlis-Zagros collision zone at the northern margin of the Arabian Plate.

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Comunicação apresentada no XVI Congresso International do Centro Latino Americano para el Desarollo (CLAD), Asunción, Paraguay de 8 a 11 Novembro 2011.

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Comunicação apresentada no XVI Congresso International do Centro Latino Americano para el Desarollo (CLAD), Asunción, Paraguay de 8 a 11 Novembro 2011.

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Comunicação apresentada no XVI Congresso International do Centro Latino Americano para el Desarollo (CLAD), Asunción, Paraguay de 8 a 11 Novembro 2011.

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Comunicação apresentada no XVI Congresso International do Centro Latino Americano para el Desarollo (CLAD), Asunción, Paraguay de 8 a 11 Novembro 2011.

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Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia Civil, Perfil de Construção

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Geociências, Museu Nac. Hist. Nat. Univ. Lisboa, nº 2, 35-84

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A água é um recurso natural único, escasso e essencial a todos os seres vivos, o que a torna um bem de extrema importância. Nos dias de hoje, o desperdício deste bem, aliado ao aumento da sua procura, tornou-se um problema devido à decrescente disponibilidade de água doce no nosso planeta. Todas as águas que rejeitamos depois da sua utilização para diversos fins, designadas de águas residuais, necessitam de tratamento antes de serem devolvidas ao meio ambiente. O seu tratamento é realizado numa Estação de Tratamento de Águas Residuais (ETAR) e o processo de tratamento depende das suas características. A ETAR das Termas de S. Vicente, em Penafiel, trabalha no seu limite de capacidade, apresenta uma sobrecarga hidráulica gerada por uma afluência de águas pluviais e o processamento das lamas geradas não permite uma secagem tão completa como seria desejável. Assim, este trabalho teve como objetivo o estudo do funcionamento desta ETAR com a finalidade de propor soluções que o possam otimizar. As soluções propostas para otimizar o funcionamento da ETAR em estudo são: i) a substituição de grades de limpeza manual por grades de limpeza automática de forma a reduzir a necessidade da intervenção do operador ao nível da remoção e condicionamento dos gradados; ii) a construção de um desarenador arejado que além de remover areias de diâmetro superior a 0,2 mm promove também a remoção de gorduras, protegendo desta forma os equipamentos a jusante da abrasão/desgaste prematuros e reduzindo a formação de depósitos nas tubagens; iii) a construção de um tanque de equalização de forma a garantir uma distribuição mais uniforme dos caudais e da carga poluente; iv) a substituição do enchimento do leito percolador por um meio de suporte plástico que permite atingir melhores eficiências de remoção neste tratamento biológico; v) a alteração do agente de desinfeção para radiação ultravioleta, evitando a adição de produtos químicos na água residual e possível formação de subprodutos prejudiciais ao ambiente, como ocorreria no caso da cloragem; e vi) a substituição da desidratação de lamas em leitos de secagem por filtros de banda, que é um processo mais rápido, que ocupa menos espaço e permite atingir elevadas eficiências de remoção de humidade. Para cada uma das sugestões são apresentadas as correspondentes especificações técnicas e dimensionamento. As sugestões de melhoria apresentadas neste trabalho constituem uma alternativa mais económica do que a ampliação da ETAR, que genericamente corresponde à duplicação da linha de tratamento atual. Devido à menor complexidade em termos de construção, estas sugestões podem vir a ser implementadas num futuro próximo, prolongando assim um pouco mais a vida útil da ETAR atual.

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Snails belonging to Biomphalaria genus were collected from some regions of Southern South America as follows: Resistencia, province of Chaco, Argentina; Assumpcion, Paraguay; Department of Maldonado of Caneloni, Uruguay; and Pôrto Alegre, Rio Grande do Sul, Brazil. The material was classified as Biomphalaria peregrina (Orbigny) twice from Uruguay and once in Brazil; B. tenagophila (Orbigny), from Argentina and Brazil; and B. straminea (Dunker) in Paraguay. Negative results were obtained from the exposition of the abone refered snail specimens to miracidia of S. mansoni from Pernambuco, Brazil.

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Proceedings IGLC-19, July 2011, Lima, Perú

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Se relatan los resultados obtenidos en el terreno seis meses y dos años post-tratamiento con las nuevas herramientas para el control de triatominos desarrolladas con apoyo de la OMS/TDR, o sea, a) pinturas insecticidas, una suspensión emulsionable de lenta liberación conteniendo el 8,3% de malathion, aplicada por rociamiento; b) potes fumígenos que, después de encendidos, echan humos que contienen cypermetrina y DDVP; c) cajas sensoras para detección de triatominos. Los ensayos en el terreno fueron realizados en Chile, Honduras y Paraguay contra tres especies principales de vectores de la enfermedad de Chagas - Triatoma infestans, T. dimidiata y Rhodnius prolixus, según el protocolo elaborado por un comité de expertos de la OMS. Los resultados indican que las pinturas insecticidas constituyen un eficaz medio de control de estos vectores en cualquiera de las condiciones estudiadas, sea en el domicilio, sea en el peridomicilio, manteniendo los porcentajes de infestación muy próximos a cero. Comparaciones preliminares de la técnica de cajas sensoras para detección de casas infestadas por triatominos, con la búsqueda hecha por personal entrenado (hora/hombre) indican esta última como la mas apropiada.

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Se presenta el caso de un paciente oriundo y procedente del Paraguay, de 40 años de edad, portador de una ulceración crónica en cara externa del pie izquierdo, de 2 meses de evolución, debida a una hialohifomicosis por Fusarium oxysporum. Se destacan las características clínicas, métodos de diagnóstico y terapeútica de esta micosis, además de las diferentes etiologías a considerar en el diagnóstico diferencial de una úlcera en personas procedentes del área tropical o subtropical.

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Chagas disease is becoming a public health problem in Latin America due to the wide distribution, the high prevalence, the magnitude of the damage caused and the difficulties to control it. In Paraguay, the disease is mainly distributed in the departments of Paraguari, Cordillera and Central. Prevalence in marginal zones, where migrations from rural populations and endemic areas make possible the urbanization of the disease, has no been studied yet. This is a descriptive study with a cross-sectional sampling and a probabilistic system recruitment carried out in school aged children from marginal zones of Asuncion to determine the prevalence of Chagas' disease. Serological methods, parasite isolation and questionnaires were used to achieve the goals. Nine hundred and fifty three children were studied to determine the prevalence of Chagas' disease in marginal zones which was 1.4%.

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Estuaries and other transitional waters are complex ecosystems critically important as nursery and shelter areas for organisms. Also, humans depend on estuaries for multiple socio-economical activities such as urbanism, tourism, heavy industry, (taking advantage of shipping), fisheries and aquaculture, the development of which led to strong historical pressures, with emphasis on pollution. The degradation of estuarine environmental quality implies ecologic, economic and social prejudice, hence the importance of evaluating environmental quality through the identification of stressors and impacts. The Sado Estuary (SW Portugal) holds the characteristics of industrialized estuaries, which results in multiple adverse impacts. Still, it has recently been considered moderately contaminated. In fact, many studies were conducted in the past few years, albeit scattered due to the absence of true biomonitoring programmes. As such, there is a need to integrate the information, in order to obtain a holistic perspective of the area able to assist management and decision-making. As such, a geographical information system (GIS) was created based on sediment contamination and biomarker data collected from a decade-long time-series of publications. Four impacted and a reference areas were identified, characterized by distinct sediment contamination patterns related to different hot spots and diffuse sources of toxicants. The potential risk of sediment-bound toxicants was determined by contrasting the levels of pollutants with available sediment quality guidelines, followed by their integration through the Sediment Quality guideline Quotient (SQG-Q). The SQG-Q estimates per toxicant or class was then subjected to georreferencing and statistical analyses between the five distinct areas and seasons. Biomarker responses were integrated through the Biomarkers Consistency Indice and georreferenced as well through GIS. Overall, in spite of the multiple biological traits surveyed, the biomarker data (from several organisms) are accordant with sediment contamination. The most impacted areas were the shipyard area and adjacent industrial belt, followed by urban and agricultural grounds. It is evident that the estuary, although globally moderately impacted, is very heterogeneous and affected by a cocktail of contaminants, especially metals and polycyclic aromatic hydrocarbon. Although elements (like copper, zinc and even arsenic) may originate from the geology of the hydrographic basin of the Sado River, the majority of the remaining contaminants results from human activities. The present work revealed that the estuary should be divided into distinct biogeographic units, in order to implement effective measures to safeguard environmental quality.