927 resultados para population control


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

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OBJETIVO: Avaliar a associação entre índice de Apgar menor que sete no 5º minuto, os fatores pré-natais e resultados pós-natais. MÉTODOS: Trata-se de estudo retrospectivo com 27.252 recém-nascidos em maternidade escola com população de baixo risco obstétrico, de janeiro de 2003 a dezembro de 2010. Prontuários de todos os casos com índice de Apgar < 7 no 5º minuto (n = 121; - 0,4%) e de 363 casos com Apgar > 7 no 5º minuto, escolhidos ao acaso, foram revisados. Os principais desfechos estudados foram: óbito neonatal, insuficiência respiratória neonatal, necessidade de intubação orotraqueal e de unidade terapia intensiva (UTI) neonatal e encefalopatia hipóxico-isquêmica. RESULTADOS: Após análise de regressão múltipla, desacelerações tardias (DIP II) (OR: 2,4; IC95%: 1,4-4,1) e período expulsivo prolongado (OR: 3,3; IC 95%: 1,3-8,3) se associaram com Apgar < 7 no 5º minuto; assim como com insuficiência respiratória ao nascimento (OR: 3,0; IC 95%: 1,3-6,9), intubação traqueal (OR: 2,5; IC 95%: 1,2-4,8), necessidade de UTI neonatal (OR: 9,5; IC 95%: 6,7-16,8) e encefalopatia hipóxico-isquêmica (OR: 14,1; IC 95%: 3,6-54,7). Nenhuma outra variável prénatal se associou com Apgar < 7 no 5º minuto (p < 0,05). CONCLUSÃO: DIP II e período expulsivo prolongado estão associados com Apgar < 7 no 5º minuto em população obstétrica de baixo risco; situação essa relacionada com maior risco de insuficiência respiratória no parto, necessidade de suporte ventilatório e encefalopatia hipóxico-isquêmica.

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The dengue virus is an arbovirus transmitted to humans through mosquito Aedes aegypti. To describe the dynamics of dengue disease within these two populations we develop a compartment model taking into account chemical controls and mechanical control applied on the mosquitoes, which are the currently available controlling mechanisms to prevent dengue disease. To mimic seasonal variations, some parameters of the model are allowed to depend on time in order to divide a calendar year in favorable and unfavorable periods regarded to the development of vector population. (c) 2007 Elsevier B.V. All rights reserved.

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

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Anopheles darlingi is the most important Brazilian malaria vector, with a widespread distribution in the Amazon forest. Effective strategies for vector control could be better developed through knowledge of its genetic structure and gene flow among populations, to assess the vector diversity and competence in transmitting Plasmodium. The aim of this study was to assess the genetic diversity of An. darlingi collected at four locations in Porto Velho, by sequencing a fragment of the ND4 mitochondrial gene. From 218 individual mosquitoes, we obtained 20 different haplotypes with a diversity index of 0.756, equivalent to that found in other neotropical anophelines. The analysis did not demonstrate significant population structure. However, haplotype diversity within some populations seems to be over-represented, suggesting the presence of sub-populations, but the presence of highly represented haplotypes complicates this analysis. There was no clear correlation among genetic and geographical distance and there were differences in relation to seasonality, which is important for malarial epidemiology.

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

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This work concerns the application of the optimal control theory to Dengue epidemics. The dynamics of this insect-borne disease is modelled as a set of non-linear ordinary differential equations including the effect of educational campaigns organized to motivate the population to break the reproduction cycle of the mosquitoes by avoiding the accumulation of still water in open-air recipients. The cost functional is such that it reflects a compromise between actual financial spending (in insecticides and educational campaigns) and the population health (which can be objectively measured in terms of, for instance, treatment costs and loss of productivity). The optimal control problem is solved numerically using a multiple shooting method. However, the optimal control policy is difficult to implement by the health authorities because it is not practical to adjust the investment rate continuously in time. Therefore, a suboptimal control policy is computed assuming, as the admissible set, only those controls which are piecewise constant. The performance achieved by the optimal control and the sub-optimal control policies are compared with the cases of control using only insecticides when Breteau Index is greater or equal to 5 and the case of no-control. The results show that the sub-optimal policy yields a substantial reduction in the cost, in terms of the proposed functional, and is only slightly inferior to the optimal control policy. Copyright (C) 2001 John Wiley & Sons, Ltd.

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The seasonality of Alphitobius diaperinus population was studied during different seasons during one year, in broiler facilities located in the center-north region of the State of São Paulo. Parasite counting was weekly carried out by the use of traps adapted from the modified model of Arends. During the experimental period, facilities were not submitted to chemical treatment, and the litter was changed between flocks. A lower number of adults and larvae was observed during autumn, with the peak registered in the summer. There was no significant difference between spring and winter averages (adults and larvae), and between spring and summer averages (adults). Average temperatures in the facilities varied from 23.4ºC (winter) to 27.1ºC (spring). The environmentally controlled systems used by the broiler industry provide an adequate habitat for A. diaperinus development. The continuous monitoring of the population of this parasite is essential for designing control strategies, and this can be accomplished by utilizing the traps used in the present experiment.

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O tripes Frankliniella schultzei Trybom (Thysanoptera: Thripidae) é um dos mais importantes vetores de tomato spotted wilt tospovirus (TSWV) na cultura do tomate no Brasil. Dois métodos de aplicação do inseticida thiamethoxam foram comparados no controle de tripes em tomate. O experimento foi conduzido em delineamento de blocos ao acaso com sete tratamentos e quatro repetições. Utilizou-se um pulverizador costal manual com lança simples provida de ponta de pulverização com jato cônico vazio JD 14-2 ou modificada, com aplicador tipo esguicho, em substituição à ponta de pulverização. Dosagens de 150 e 200 g i.a. ha-1 foram usadas em única aplicação com esguicho e 50 g i.a. ha-1 em pulverizações semanais, iniciadas aos 48 dias após a semeadura. A eficiência do inseticida em teste foi comparada com diafenthiuron (400 g i.a. ha-1), profenofos + cypermethrin (320+32 g i.a. ha-1, respectivamente) e methamidophos (60 g i.a. 100 L-1 de água), aplicados em pulverização. Não houve diferença estatística entre os métodos de aplicação e doses com thiamethoxam no controle de F. schultzei aos 24 dias após a aplicação, sendo vantajosa a realização de uma única aplicação das maiores dosagens de thiamethoxam com esguicho em comparação às aplicações semanais da menor dosagem em pulverização. A eficiência de controle do tripes com o inseticida thiamethoxam variou de 93 a 95%, nos diferentes métodos e dosagens em teste. Diafenthiuron e profenofos + cypermethrin apresentaram eficiência menor (78 e 88%, respectivamente), porém foram superiores às obtidas com methamidophos (71%). Os produtos e doses utilizados não causaram fitotoxicidade às plantas de tomate.

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A proliferação do Aedes aegypti é propiciada pelo habito de permitir a formação de criadouros em vários tipos de recipientes. Uma das formas de controla-lo é a disseminação do conhecimento sobre o vetor, por conduzir a conscientização e a tomada de medidas contra a sua proliferação. Para avaliar um método de ensino sobre o vetor e a dengue, foram comparando alunos de 5ª e 6ª séries antes e após a intervenção didática. Os alunos com intervenção foram mais aptos em reconhecerem as fases do ciclo e tiveram um discernimento maior sobre a importância dos mosquitos para a saúde. Eles também foram mais aptos em reconhecerem quais medidas de controle são mais eficientes e viáveis, repercutindo em suas residências que apresentaram duas vezes menos criadouros em relação aos que não tiveram intervenção.

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This review concerns the phenomenon of heterogeneous growth (Het-G) in fish. Het-G is characterized by different growth rates between conspecifics. Although genetic determination on Het-G is recognized, grouping increases the difference in size between conspecifics. This review focuses on population factors and the mechanisms underlying the socially mediated Het-G are summarized and discussed. The aim of this paper is to arrive at a general statement explaining why grouping decreases mean growth and why it suppresses growth only in some individuals. The mechanisms described are: a) food competition, b) chemical factors released by conspecifics, and c) social stress. Social stress is analyzed in terms of the effect on appetite, digestive processes and metabolism. It is proposed that the predominant mechanism promoting socially mediated growth suppression is related to the social habit of the species. The biological significance of growth heterogeneity in fish is also discussed. Growth variability is suggested as an adaptative strategy to optimize survival of the population in a restricted space.

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Dentin sialoprotein (DSP) and dentin phosphoprotein (DPP), the major dentin proteins, have been shown to induce neutrophil migration through release of IL-1beta, TNF-alpha, MIP-2, and KC. However, the sources of these mediators were not determined. Here, the roles of macrophages and mast cells (MC) in dentin-induced neutrophil accumulation were investigated. Peritoneal MC depletion or the enhancement of macrophage population increased DSP- and DPP-induced neutrophil extravasation. Moreover, supernatants from DSP- and DPP-stimulated macrophages caused neutrophil migration. The release of neutrophil chemotactic factor by macrophages was inhibited by dexamethasone or the supernatant of DSP- treated MC. Consistently, dexamethasone and the MC supernatant inhibited the production of IL-1beta, TNF-alpha, and MIP-2 by macrophages. This inhibitory activity of the DSP- stimulated MC was neutralized by anti-IL-4 and anti-IL-10 antibodies. These results indicate that dentin induces the release of the neutrophil chemotactic substance(s) by macrophages, which are down-modulated by MC-derived IL-4 and IL-10.

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Aedes aegypti from the Brazilian cities of Sao Jose do Rio Preto (SJ) and Goiania (GO) were analyzed as to their esterase patterns and the results were compared with data obtained about 5 years before for SJ population. Esterase bands not detected in the previous study were now observed in mosquitoes from both SJ and GO populations, being the last considered a population resistant to insecticides. Other similarities between SJ and GO populations in this study, and some differences in comparison with the previous data on SJ were observed, involving, in addition to changes in band type, changes in frequency of mosquitoes expressing them and differential gene activation during development. As it is generally true for genetic features, changes in the esterase patterns are expected to be the result of factors such as selection by environmental conditions and genetic drift. In the present case, continuous use of insecticides aiming mosquito population size control in SJ by sanitary authorities could be involved in the observed changes. Changed esterases were classified as carboxylesterases and cholinesterases, which are enzymes already shown to take part in the development of resistance in several organisms. In addition, data obtained in the elapsed time by authorities responsible for the mosquito control has shown increasing insecticide resistance of SJ population mosquitoes parallel to increase in the total amount of esterases, reinforcing the mentioned possibility.