1000 resultados para sazonalidade da infestação


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In recent work (Kroll, 1990) on dairy cattle growth using its monthly weights, a Gompertz function, first considering the autocorrelated error structure, and second, the independent error structure, was fitted. The last explained 25% more of the total variance than the former. In this work, a Gompertz function was fitted with autocorrelated error structure adding seasonality to the model. This was suggested taking into account the time series autocorrelation function. In order to estimate the six parameters, an iterative procedure was used, employing a matrix X = [G\S], where G is the usual matrix for fitting the Gompertz function, and S is a 0s, 1s, -1s matrix necessary to take into account seasonality. With this model, the adjustment was better in terms of the coefficient determination.

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The objective of this work was to carry a descriptive analysis in the monthly precipitation of rainfall stations from Rio de Janeiro State, Brazil, using data of position and dispersion and graphical analyses, and to verify the presence of seasonality and trend in these data, with a study about the application of models of time series. The descriptive statistics was to characterize the general behavior of the series in three stations selected which present consistent historical series. The methodology of analysis of variance in randomized blocks and the determination of models of multiple linear regression, considering years and months as predictors variables, disclosed the presence of seasonality, what allowed to infer on the occurrence of repetitive natural phenomena throughout the time and absence of trend in the data. It was applied the methodology of multiple linear regression to removal the seasonality of these time series. The original data had been deducted from the estimates made by the adjusted model and the analysis of variance in randomized blocks for the residues of regression was preceded again. With the results obtained it was possible to conclude that the monthly rainfall present seasonality and they don't present trend, the analysis of multiple regression was efficient in the removal of the seasonality, and the rainfall can be studied by means of time series.

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This paper represents the results of the work carried out in order to study the condition of seasonal consumer, the load factor and the more convenient tariff for a sugar mill located in the Vale do Paranapanema, SP, Brazil. Therefore, data of consume and registered demand were collected during the quadriennium 1990 to 1994. The studies showed that the factory did not maintain the condition of seasonal consumer of electric energy during the analysed period. Low values of the load factor observed in the period showed a non rational use of electric energy supplied by the concessionary. The results showed that only in one situation (load retired in top equal to 90%) the most convenient tariff is the horo-sazonal azul. In the other situations the most convenient tariff is the conventional one.

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The present study was conducted in the Aquaculture Station of Hydroeletric Power Station situated in Volta Grande Reservoir, MG, Brazil. Seventy freshwater corvinas, Plagiscion squamosissimus, and 66 tucunarés, Cichla ocellaris were captured bimonthly from April 2000 through April 2001 with net and hook. The helmints were identified as Diplostomun (A.) compactmn which showed the highest prevalence in the corvina's eyes in April 2000 (70%), February 2001 (80%) and April 2001 (60%), while in tucunaré occurred in April 2000 (33.3%), August 2000 (18.2%) and October 2000 (18.2%). Nevertheless, increase in the mean intensity of parasites was related in April (6.6), June (6.0), August (18.5) 2000 and February (5.7), April (4.8) 2001 for corvina and in August (16.0) and October (7.0) 2000 for tucunaré. Corvina's females showed infection during all period, while males did not show the same prevalence in June 2000 and April 2001. On the other hand, tucunare's males were infected in all months while females in August and October 2000. The highest prevalence in corvina was observed in the months which presented elevated water temperature (April, October, December 2000 and April 2001). The number of parasites collected in corvina on February 2000 was higher than the one observed in August 2000. The same was not observed for tucunaré. This work demonstrate corvina's high susceptibility to metacercariae of Diplostomum.

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This paper aims at evaluating the occurrence of Diplostommn (Anstrodiplostomum compactum (Digenea: Diplostomatidae) in the eyeball of Plagioscion sqnamosissimus (corvina) and Cichla ocellaris (tucunaré), monthly captured in Paraná river, Presidente Epitácio, state of São Paulo, Brazil. From 61 corvinas under analysis, 56 of them contained parasites (92%) with intensity rate of 42.0 host parasites. From an amount of 81 tucunarés, 45 contained parasites (55%) with intensity rate of 9.3 parasites. Corvinas showed prevalence from 71 to 100% with the highest intensity rates (103.3 and 106.9) from February to March, 2001. Comparatively, the tucunaré showed the highest prevalence from November 2000 (90%) to February 2001 (80%). The tucunaré highest intensity rates occurred on September, 2000 (12.7), December, 2000 (12.2) and February, 2001 (16.1). Metacercariae showed a hollow womb body and a posterior region of a sinuous conic protuberance, an oral sucker smaller than the acetabulae, a simple acetabulae located in the pre-equatorial region of helminto. A short pre-pharynx followed by a muscular pharynx, genital pore next to acetubulae. Corvina metacercariae presents 1.434,0 μm (880 to 1.840) long by 611.2 ± 93.4 μm (400 to 792) wide. Tucunaré metacercariae, 1.462.4 μm (960 to 2.480) by 710.8 μm (560 to 960). Authors confirmed corvina great susceptibility to Diplomastum and the relationship between the parasitism and the aquatic and climatic parameters.

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The boll weevil (Anthonomus grandis Boheman, 1843) (Coleoptera: Curculionidae) is a pest that limits the production of cotton, especially in the North East of Brazil. The present study aimed to estimate the infestation index and natural mortality of boll weevil at Caraibas County, located in the semi-arid of the Southwest ofBahia. The experiment was performed using the cultivar BSR Aroeira, at Fazenda Lagoa Seca, in 2006. Weekly evaluations were performed, in five sampling areas 25m2, collecting blossoms fallen on the ground. The infestation was estimated by counting the oviposition punctures and /or the feeding on blossoms, and also by the presence of one of the phases of the boll weevil in the inside. Mortality factors were studied through the dissection of blossoms, estimating predation, parasitism, dissection and disease. The results obtained allowed to conclude that the boll weevil determines high infestation levels in the region. Parasitism, dissection and predation, following this order, determine high rates of real mortality of the pest. Catolaccus grandis Burks, 1954 (Hymenoptera: Pteromalidae) and Bracon sp.(Hymenoptera: Braconidae) are parasitoids of boll weevil reported in sothwestern Bahia, being the first one the predominant species. © 2009, Sociedad Venezolana de Entomología.

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The aim of this work was to investigate monthly, for one year the seasonality effect on the physicochemical properties (dry weight, flavonoids contents, pH and antioxidant activity) of ethanolic extract (EAP) of propolis produced by three different techniques (intelligent propolis collector, plastic screen or scraping) fifteen colonies of africanized bees. No differences (p>0.05) in the physicochemical properties due to the technique of propolis production and seasonality were observed.

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The knowledge about population fluctuation of fruit flies (Diptera: Tephritidae) is an important tool to be adopted in pest control. Thus, this research aimed to analyse the population fluctuation of adults of fruit flies and the infestation of larvae in fruits depending on the conventional and organic agricultural systems of guava production in the 2010/2011 harvest. For monitoring the adults of fruit flies, five yellow sticky traps were installed in each system. The infestation percentage and the calculation of the ratio number of larvae/number of fruits were determined at harvest by harvesting 10 mature fruits/plant, in ten plants, for each system. In organic system predominated Anastrepha spp., principally in the period when the fruits were ripening or ripe, represented by elevated infestation percentage, while the conventional system presented low population density of fruit flies, with reduced larvae infestation inside the fruits.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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

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Pós-graduação em Biologia Animal - IBILCE

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)