983 resultados para larvae tanks
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Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia Mecância
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Trabalho de Projecto para obtenção do grau de Mestre em Engenharia Civil Perfil Estruturas
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Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia Civil na Área de Especialização de Hidráulica
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OBJECTIVE: To evaluate the most productive types of properties and containers for Aedes aegypti and the spatial distribution of entomological indices.METHODS: Between December 2006 and February 2007, the vector's immature forms were collected to obtain entomological indices in 9,875 properties in the Jaguare neighborhood of Sao Jose do Rio Preto, SP, Southeastern Brazil. In March and April 2007, a questionnaire about the conditions and characteristics of properties was administered. Logistic regression was used to identify variables associated with the presence of pupae at the properties. Indices calculated per block were combined with a geo-referenced map, and thematic maps of these indices were obtained using statistical interpolation.RESULTS: The properties inspected had the following Ae. aegypti indices: Breteau Index = 18.9, 3.7 larvae and 0.42 pupae per property, 5.2 containers harboring Ae. aegypti per hectare, 100.0 larvae and 11.6 pupae per hectare, and 1.3 larvae and 0.15 pupae per inhabitant. The presence of yards, gardens and animals was associated with the presence of pupae.CONCLUSIONS: Specific types of properties and containers that simultaneously had low frequencies among those positive for the vector and high participation in the productivity of larvae and pupae were not identified. The use of indices including larval and pupal counts does not provide further information beyond that obtained from the traditional Stegomyia indices in locations with characteristics similar to those of São José do Rio Preto. The indices calculated per area were found to be more accurate for the spatial assessment of infestation. The Ae. aegypti infestation levels exhibited extensive spatial variation, indicating that the assessment of infestation in micro areas is needed.
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In the present work, we studied a common outbreaking Lepidoptera species in Portuguese pine stands – Thaumetopoea pityocampa (Den. & Schiff.) - and one of its potential predators – Parus major (L.). The population dynamics of the immature stages of the Lepidoptera was studied in several types of Pinus pinaster (Aiton) plantations in three different areas: Setúbal Peninsula, Abrantes and National Pine Forest of Leiria. Location and plantation structure was the most important factors determining population density of T. pityocampa. Setubal and Abrantes was highly susceptible to attacks by the Lepidoptera, whereas Leiria had lower densities. Young and homogeneous pine stands was more susceptible to attacks than older and more heterogeneous pines stands. However, a desynchronized population of T. pityocampa, in which the larvae develops during summer instead of during winter, reached high densities also in Leiria. The impact of several mortality factors and climatic conditions on the immature stages of the insect (eggs and larvae), in normal and desynchronized populations are discussed, as well as possible evolutionary implications of the sudden appearance of the new version of T. pityocampa. The break of the pupa diapause and adult emergence times the annual life cycle of this insect. Adults from the desynchronized population emerged earlier than adults from the normal population, which in turn determined the change in the larvae development period. Different factors, potentially affecting the timing of adult emergence in both normal and abnormal populations are also discussed. To study P. Major, nest-boxes were placed in the areas of Setúbal and Leiria and they were monitored during three seasons. The nest-boxes increased the density of breeding and wintering birds in the studied pine plantations, indicating that a lack of natural holes are in fact a limiting factor for this populations. The earliest breeding start for this species was recorded in my study area, indicating that Portuguese coastal pines provide good breeding conditions earlier than in other areas of Europe and North Africa. This leads to an overlap between the end of the larvae stage of T. pityocampa and the beginning of the breeding season of P. major. Key-words: Thaumetopoea pityocampa, Parus major, Pinus pinaster, population dynamics, Portugal.
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ABSTRACT This is the description of how nine Aedes aegypti larvae were found in a natural breeding site in the Pinheiros neighborhood, city of Sao Paulo, SP, Southeastern Brazil. The record was conducted in December 2014, during an entomological surveillance program of dengue virus vectors, with an active search of potential breeding sites, either artificial or natural. Finding Ae. aegypti larvae in a tree hole shows this species’ ability to use both artificial and natural environments as breeding sites and habitats, which points towards the importance of maintaining continuous surveillance on this mosquito in all kinds of water-holding containers.
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The effects of in vitro incubation of three henzimidazole anthelmintics, thiabendazole, mebendazole and cambendazole on Strongyloides were compared. No drug affected hatching of S. ratti eggs or the viability of infective larvae or parasitic adult worms, but all three inhibited moulting of S. ratti larvae. In addition, cambendazole, but not thiabendazole or mebendazole, impaired the viability of S. ratti first- and second-stage larvae. The three drugs had no effect on isolated S. stercorais free-living adult worms, but they all prevented development of S. stercoralis rhabditiform larvae. Thiabendazole and mebendazole had no effect on the infectivity of either S. ratti or S. stercoralis infective larvae, but infection with these worms was abrogated by prior incubation with cambendazole. These results indicate that cambendazole acts in a different manner to the other two drugs. Since it is active against larvae migrating through the tissues, it is potentially of much greater value than thiabendazole or mebendazole in the therapy of strongyloidiasis.
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For the therapy of human strongyloidiasis, are necessary effective drugs to eliminate both larvae and adult worm parasitism, which may also be used by parenteral route, to obviate the particular conditions presented by many patients. A study based on the experimental infection by Strongyloides venezuelensis in rats was done, administering injectable ivermectin or levamizole. Both drugs were shown to be active, when used in single doses of 0.2 to 0.5 mg/kg of ivermectin, or 26 mg/kg for levamizole. Ivermectin was slightly more effective as far as larval stage of the infection is concerned, and the same happened for levamisole for the adult worm stage. Promising perspectives are visualized to improve the therapy of patients with serious disseminated infection by Strongyloides stercoralis.
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The injection of cercariae of Schistosoma mansoni into the peritoneal cavity of naive mice induces cell adhesion to these larvae, and this adherence sharply decreases when the infecting larva changes to schistosomule. This procedure was used to detect differences between schistosomules obtained in vivo and in vitro. Reinoculation of schistosomules obtained in vivo into the peritoneal cavity of mice did not trigger cell adhesion. In contrast, adherent cells were found in 4 and 24-hour-in vitro schistosomules. Our data on schistosomules obtained in vitro indicate that more than 24 hours are needed for complete remotion of molecules involved in the phenomenon of cell adhesion.
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In the experimental schistosomiasis mansoni glucocorticoids cause a reduction in the worm burden when administered in the week of infection or, the longest, at the next week. In order to determinate the probable(s) site(s) of reduction of the worm burden, mice were infected with cercariae of LE strain of S. mansoni and dexamethasone was administered daily (50 mg/kg, subcutaneously) starting 1 hour before infection until the eighth day. Mice were sacrificed daily starting on the third day after infection until the ninth day, and schistosomula from lungs were collected. Six weeks after infection, the remaining mice were sacrificed and perfused for adult worm recovery. Analysis of the results showed that the non-treated mice presented larger numbers of lung larvae than the treated ones, and this difference was also found later in the worm burden in the portal system. This difference may reflect the early death of larvae in treated animals, before or after reaching the lungs.
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An enzyme-linked immunosorbent assay (ELISA), employing antigens from Toxocara canis larvae and the absortion of suspected sera with Ascaris lumbricoides extracts was used in a seroepidemiological study performed in five municipalities of São Paulo State, Brazil (São Paulo, Campinas, Santos, Marília and Presidente Prudente) in order to determine the frequency of antibodies to Toxocara. In 2,025 blood samples collected, 806 proceeded from male subjects and 1,219 from females; 483 samples were collected from subjects under 15 years of age and the remaining 1,542 from subjects aged 15 years or over. Among the 2,025 sera investigated, 3.60% had antibodies to Toxocara at significant levels. A moderate predominance of infection with Toxocara among male subjects (3.72%) was observed, although the difference was not statistically significant when this rate was compared with that for female (3.28%). Related to age, a higher frequency of positive results was detected among subjects under 15 years (6.41%) against the older group (2.53%). A trend of more elevated rates of infection was observed in municipalities with high demographic densities (São Paulo, Campinas and Santos). Nevertheless, such findings only appeared to be statistically significant in subjects younger than 15 years.
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The peritoneal cavity of laboratory mice was used to study the phenomenon of host cell adhesion to different evolutive stages of the Schistosoma mansoni (cercaria, adult worm, developing and mature eggs, miracidium, young and mature daughter sporocysts). Material recovered from the peritoneal cavity 30 and 180 min after the inoculation of each evolutive form was examined with the help of a stereomicroscope. The free swimming larvae (cercaria and miracidium), and the evolutive forms producing such larvae (mature egg and mature daughter sporocyst) elicited the host cell adhesion phenomenon. In all forms but cercariae the adherent cells remained as so till 180 minutes after inoculation
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The life cycle of Lagochilascaris minor was studied using material collected from human lesion and applying the experimental model: rodents (mice, hamsters), and carnivorae (cats, dogs). In mice given infective eggs, orally, hatch of the third stage larvae was noted in the gut wall, with migration to liver, lungs, skeletal musculature and subcutaneous tissue becoming, soon after, encysted. In cats infected with skinned carcasses of mice (60 to 235 days of infection) it was observed: hatch of third stage larvae from the nodules (cysts) in the stomach, migration through the oesophagus, pharynx, trachea, related tissues (rhino-oropharynx), and cervical lymphonodes developing to the mature stage in any of these sites on days 9-20 post inoculation (P.I.). There was no parasite development up to the mature stage in cats inoculated orally with infective eggs, which indicates that the life cycle of this parasite includes an obligatory intermediate host. In one of the cats (fed carcass of infected mice) necropsied on day 43 P.I., it was observed the occurence of the self-infective cycle of L. minor in the lung tissues and in the cervical region which was characterized by the finding of eggs in different stages of development, third stage larvae and mature worms. It's believed that some component of the carnivorae gastrointestinal tracts may preclude the development of third stage larvae from L. minor eggs what explains the interruption of the life cycle in animals fed infective eggs. It's also pointed out the role of the intermediate host in the first stages of the life cycle of this helminth.
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CO2 capture from gaseous effluents is one of the great challenges faced by chemical and environmental engineers, as the increase in CO2 levels in the Earth atmosphere might be responsible for dramatic climate changes. From the existing capture technologies, the only proven and mature technology is chemical absorption using aqueous amine solutions. However, bearing in mind that this process is somewhat expensive, it is important to choose the most efficient and, at the same time, the least expensive solvents. For this purpose, a pilot test facility was assembled and includes an absorption column, as well as a stripping column, a heat exchanger between the two columns, a reboiler for the stripping column, pumping systems, surge tanks and all necessary instrumentation and control systems. Some different aquous amine solutions were tested on this facility and it was found that, from a set of six tested amines, diethanol amine is the one that turned out to be the most economical choice, as it showed a higher CO2 loading capacity (0.982 mol of CO2 per mol of amine) and the lowest price per litre (25.70 ¤/L), even when compared with monoethanolamine, the benchmark solvent, exhibiting a price per litre of 30.50 ¤/L.
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Treatment with dexamethasone (DMS) in the early phases of the experimental Schistosoma mansoni infection causes an indirect effect on the cercaria-schistosomulum transformation process. This is observed when naive albino mice are treated with that drug (50 mg/Kg, subcutaneously) and infected intraperitonealy 01 hour later with about 500 S. mansoni cercariae (LE strain). An inhibition in the host cell adhesion to the larvae, with a simultaneous delay in the cercaria-schistosomulum transformation, is observed. This effect is probably due to a blockade of the neutrophil migration to the peritoneal cavity of mice, by an impairment of the release of chemotactic substances. Such delay probably favors the killing of S. mansoni larvae, still in the transformation process, by the vertebrate host defenses, as the complement system.