961 resultados para periodicity fluctuation


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INTRODUCTION: Sylvatic yellow fever (SYF) is enzootic in Brazil, causing periodic outbreaks in humans living near forest borders or in rural areas. In this study, the cycling patterns of this arbovirosis were analyzed. METHODS: Spectral Fourier analysis was used to capture the periodicity patterns of SYF in time series. RESULTS: SYF outbreaks have not increased in frequency, only in the number of cases. There are two dominant cycles in SYF outbreaks, a seven year cycle for the central-western region and a 14 year cycle for the northern region. Most of the variance was concentrated in the central-western region and dominated the entire endemic region. CONCLUSIONS: The seven year cycle is predominant in the endemic region of the disease due the greater contribution of variance in the central-western region; however, it was possible identify a 14 cycle that governs SYF outbreaks in the northern region. No periodicities were identified for the remaining geographical regions.

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This study uses a VAR methodology to evaluate the impact of the macroeconomic conditions and money supply in the fluctuation of nonperforming loans for the Portuguese economy. Additionally, the feedback effect of nonperforming loans growth to the economy and specially to the credit supply is analised. The study is motived by the hypothesis that loan quality is procyclical and that the fast growth of credit supply has a positive relation with the growth of nonperforming loans. The hypothesis that nonperforming loans reinforce economic fragilities and credit market frictions is also tested. Empirical results corroborate both hypothesis presented. Hence, it was possible to establish that the macroeconomic conditions measured by GDP and unemployment and the fast growth of credit supply contribute to the development of nonperforming loans. Furthermore, the growth of nonperforming loans reinforces the economic cycle, as it contributes to the deterioration of macroeconomic conditions and creates frictions in the credit market that may results in a credit crunch.

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INTRODUCTION: Leprosy in Brazil is a public health issue, and there are many regions in the State of Espírito Santo with high endemic incidence levels of leprosy, characterizing this state as a priority for leprosy programs. The aim of this study was to determine the spatial distribution of coefficients of new cases of leprosy in the State of Espírito Santo, Brazil. METHODS: We conducted a descriptive and ecologic study based on the spatial distribution of leprosy in the State of Espírito Santo between 2004 and 2009. Data were gathered from the available records of the Espírito Santo State Health Secretary. The global and local Bayesian empirical methods were used to produce an estimate of leprosy risk, smoothing the fluctuation effects of the detection coefficients. RESULTS: The study resulted in a coefficient adjustment of new cases in 10 towns that changed their classification, among which, 2 went from low to medium, 4 from medium to high, 3 from high to very high, and 1 from very high to hyper-endemic. An average variation of 1.02, fluctuating between 0 and 12.39 cases/100,000 inhabitants, was found in a comparative calculation between the Local Ebest value and the average coefficient of new leprosy cases in the State of Espírito Santo. CONCLUSIONS: The spatial analysis of leprosy favors the establishment of control strategies with a better cost-benefit relationship since it reveals specific and priority regions, thereby enabling the development of actions that can interfere in the transmission chain.

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Introduction Leprosy remains a relevant public health issue in Brazil. The objective of this study was to analyze the spatial distribution of new cases of leprosy and to detect areas with higher risks of disease in the City of Vitória. Methods The study was ecologically based on the spatial distribution of leprosy in the City of Vitória, State of Espírito Santo between 2005 and 2009. The data sources used came from the available records of the State Health Secretary of Espírito Santo. A global and local empirical Bayesian method was used in the spatial analysis to produce a leprosy risk estimation, and the fluctuation effect was smoothed from the detection coefficients. Results The study used thematic maps to illustrate that leprosy is distributed heterogeneously between the neighborhoods and that it is possible to identify areas with high risk of disease. The Pearson correlation coefficient of 0.926 (p = 0.001) for the Local Method indicated highly correlated coefficients. The Moran index was calculated to evaluate correlations between the incidences of adjoining districts. Conclusions We identified the spatial contexts in which there were the highest incidence rates of leprosy in Vitória during the studied period. The results contribute to the knowledge of the spatial distribution of leprosy in the City of Vitória, which can help establish more cost-effective control strategies because they indicate specific regions and priority planning activities that can interfere with the transmission chain.

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RESUMO - Os resíduos hospitalares (RH) perigosos — Grupos III e IV — produzidos na prestação de cuidados domiciliários (CD), dada a sua composição, infecciosidade, toxicidade, mobilidade e persistência, constituem um perigo relevante. A exposição a estes resíduos traduz-se num risco importante para os profissionais de saúde, doentes e seus familiares. Dado que em muitas situações estes resíduos ficam no domicílio dos doentes, sendo posteriormente depositados nos contentores camarários, o risco é alargado ao público em geral, aos catadores e aos profissionais de recolha de resíduos sólidos urbanos dos municípios. Através de um estudo observacional, transversal, com componente analítica, da produção de RH pretende-se determinar e caracterizar os quantitativos dos Grupos III e IV produzidos na prestação de CD em 2003 no concelho da Amadora, identificando também o seu destino final. Utiliza- se uma amostra aleatória do universo de doentes submetidos a tratamento domiciliário em 2003 e efectua-se a análise da associação estatística das variáveis peso do Grupo III e peso do Grupo IV com as variáveis relativas às características do doente (sexo, idade e doença), do tratamento (duração e periodicidade) e sazonais (época do ano). A média do peso produzido dos RH por acto prestado é de 213,1 g para o Grupo III e de 3,8 g para o Grupo IV. Estima--se uma produção de RH do Grupo III na prestação de CD, em 2003, no concelho da Amadora entre 8,8 e 11,4 t e para os RH do Grupo IV um valor de 10,2 kg. Verifica-se que, por acto prestado, a produção média de resíduos do Grupo III é maior nos doentes mais idosos, nas úlceras varicosas, no pé diabético, na escara de pressão, nas situações de maior duração do tratamento e nos doentes submetidos a três tratamentos por semana. Também por acto prestado, a produção média de RH do Grupo IV é maior nos doentes mais novos, na patologia osteo-articular, na infecção, no acidente, no pós-operatório, nas situações de menor duração do tratamento e nos doentes submetidos a seis tratamentos por semana (o que está relacionado com as patologias em causa). As produções médias, por acto prestado, de ambos os grupos não apresentam relação com as variáveis idade e época do ano. Todos os RH produzidos nos actos prestados em CD, em 2003, no concelho da Amadora foram depositados nos contentores municipais. Recomendam-se acções de formação e de informação dirigidas aos profissionais de saúde e ao público em geral, a criação de condições para que os RH produzidos nos CD sejam transportados, em condições adequadas, para os centros de saúde e uma articulação entre os órgãos de gestão dos centros de saúde, a autarquia, os operadores de gestão de RH e os serviços de saúde pública no sentido de serem encontradas soluções apropriadas e inovadoras relativamente à gestão dos RH produzidos na prestação de CD.

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\The idea that social processes develop in a cyclical manner is somewhat like a `Lorelei'. Researchers are lured to it because of its theoretical promise, only to become entangled in (if not wrecked by) messy problems of empirical inference. The reasoning leading to hypotheses of some kind of cycle is often elegant enough, yet the data from repeated observations rarely display the supposed cyclical pattern. (...) In addition, various `schools' seem to exist which frequently arrive at di erent conclusions on the basis of the same data." (van der Eijk and Weber 1987:271). Much of the empirical controversies around these issues arise because of three distinct problems: the coexistence of cycles of di erent periodicities, the possibility of transient cycles and the existence of cycles without xed periodicity. In some cases, there are no reasons to expect any of these phenomena to be relevant. Seasonality caused by Christmas is one such example (Wen 2002). In such cases, researchers mostly rely on spectral analysis and Auto-Regressive Moving-Average (ARMA) models to estimate the periodicity of cycles.1 However, and this is particularly true in social sciences, sometimes there are good theoretical reasons to expect irregular cycles. In such cases, \the identi cation of periodic movement in something like the vote is a daunting task all by itself. When a pendulum swings with an irregular beat (frequency), and the extent of the swing (amplitude) is not constant, mathematical functions like sine-waves are of no use."(Lebo and Norpoth 2007:73) In the past, this di culty has led to two di erent approaches. On the one hand, some researchers dismissed these methods altogether, relying on informal alternatives that do not meet rigorous standards of statistical inference. Goldstein (1985 and 1988), studying the severity of Great power wars is one such example. On the other hand, there are authors who transfer the assumptions of spectral analysis (and ARMA models) into fundamental assumptions about the nature of social phenomena. This type of argument was produced by Beck (1991) who, in a reply to Goldstein (1988), claimed that only \ xed period models are meaningful models of cyclic phenomena".We argue that wavelet analysis|a mathematical framework developed in the mid-1980s (Grossman and Morlet 1984; Goupillaud et al. 1984) | is a very viable alternative to study cycles in political time-series. It has the advantage of staying close to the frequency domain approach of spectral analysis while addressing its main limitations. Its principal contribution comes from estimating the spectral characteristics of a time-series as a function of time, thus revealing how its di erent periodic components may change over time. The rest of article proceeds as follows. In the section \Time-frequency Analysis", we study in some detail the continuous wavelet transform and compare its time-frequency properties with the more standard tool for that purpose, the windowed Fourier transform. In the section \The British Political Pendulum", we apply wavelet analysis to essentially the same data analyzed by Lebo and Norpoth (2007) and Merrill, Grofman and Brunell (2011) and try to provide a more nuanced answer to the same question discussed by these authors: do British electoral politics exhibit cycles? Finally, in the last section, we present a concise list of future directions.

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Relatório de estágio de mestrado em Ensino do 1.º e 2.º Ciclo do Ensino Básico

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We investigate the low-energy electronic transport across grain boundaries in graphene ribbons and infinite flakes. Using the recursive Green’s function method, we calculate the electronic transmission across different types of grain boundaries in graphene ribbons. We show results for the charge density distribution and the current flow along the ribbon. We study linear defects at various angles with the ribbon direction, as well as overlaps of two monolayer ribbon domains forming a bilayer region. For a class of extended defect lines with periodicity 3, an analytic approach is developed to study transport in infinite flakes. This class of extended grain boundaries is particularly interesting, since the K and K0 Dirac points are superposed.

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Esta investigação aborda a qualidade da produção noticiosa sobre o erro médico, como um fator essencial na construção do conhecimento público sobre o tema, com o objetivo de compreender que características definem tal produção e até que ponto poderão ser explicadas pela periodicidade e orientação editorial dos jornais; que conceito de erro médico é veiculado pela produção noticiosa sobre o tema; e quais são os protagonistas no discurso jornalístico sobre o erro médico. Foram analisadas as edições de três jornais portugueses, de 2008 a 2011, resultando num corpus de 266 (4,2%) artigos, que foram classificados de acordo com as seguintes variáveis: as fontes de informação citadas (o seu estatuto e especialidade, no caso dos médicos); os temas que são tratados; as características de enquadramento da informação publicada (tom, género jornalístico; e a presença e número de fontes de informação). Pela análise de conteúdo quantitativa, apurou-se que esse tema está em crescimento, essencialmente com notícias de tom negativo e fontes de informação habitualmente identificadas. Não há evidência para afirmar que a periodicidade e a orientação editorial expliquem as variações dessas características, a não ser relativamente ao número de fontes citadas. Vigoram as notícias centradas nos resultados dos erros (mortes ou lesões), provocados por "erros de omissão" e por "erros de comissão", envolvendo uma diversidade de protagonistas: são, tal como acontece na informação sobre saúde em geral, fontes oficiais e especializadas do campo da saúde. Destacam-se os médicos e os juristas e é dado relevo aos pacientes.

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Dissertação de mestrado em Optometria Avançada

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In order to investigate the population fluctuation of Diptera in a poultry house in Pelotas, Rio Grande do Sul, Brazil, six collection methods were utilized: 1 (0 to 7 day-old feces from chickens), 2 (7 to 14 day-old feces), 3 (14 to 21 day-old feces), 4 (0 to 21 day-old feces), 5 (accumulated feces) and 6 (tube trap). Analyses of polynomial regression were accomplished independent of the collection method. The survey was conducted from August 1998 to July 1999 in chicken houses at the Conjunto Agrotécnico Visconde da Graça. A total of 28,720 Diptera were collected, including the following species: Coproica sp. and Telomerina flavipes (Meigen, 1830) (15,640); Drosophila repleta Wollaston, 1858 (9,229); Dohrniphora cornuta (Bigot, 1857) (2,539); Ischiolepta scabricula (Haliday, 1833) (544); Lestodiplosis sp. (320); Muscina stabulans (Fallen, 1817) (159); Musca domestica L., 1758 (143); Drosophila melanogaster Meigen, 1830 (95); Telmatoscopus albipunctatus Williston, 1893 (21); Rhegmoclema sp. (14); Fannia canicularis (L., 1761) (7); Stomoxys calcitrans (L., 1758) (2); and unidentified species of Psychodidae (6) and Muscidae (1). The greatest number of species occurred in October, November and December and the fewest in August, September and April. The greatest abundance of Diptera was recorded in October (9,092), while the lowest index of capture was noted in April (658). The population fluctuation was estimated for Coproica sp. and T. flavipes, D. repleta, D. cornuta, I. scabricula and Lestodiplosis sp.

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To estimate the populational fluctuation of Chrysomya Robineau-Desvoidy, 1830 species and the relation of populational abundance around, six wind oriented trap (WOT) were placed in three distinct ecological areas (urban, rural and wild) in Pelotas, Rio Grande do Sul, Brazil, from February/1993 to January/1995. The flies were weekly collected. Captured species were Chrysomya albiceps Wiedmann, 1819, C. megacephala Fabricius, 1794 and C. putoria Wiedmann, 1830 with respective abundance of 64.5%, 19.7% and 0.9%, representing a total of 85.0% of 409,920 specimens of Calliphoridae. The three species demonstrated similarity in the populational fluctuation, except in the abundance. The populational peak ocurred in autum when the temperature decreases. In the months of July to November no fly was collected, recomposing the population in December, when the temperature surpassed 20ºC.

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Drosophila Fallen, 1823 (Diptera, Drosophilidae) is for long a well-established model organism for genetics and evolutionary research. The ecology of these flies, however, has only recently been better studied. Recent papers show that Drosophila assemblies can be used as bioindicators of forested environment degradation. In this work the bioindicator potential of drosophilids was evaluated in a naturally opened environment, a coastal strand-forest (restinga). Data from nine consecutive seasonal collections revealed strong temporal fluctuation pattern of the majority of Drosophila species groups. Drosophila willistoni group was more abundant at autumns, whereas D. cardini and D. tripunctata groups were, respectively, expressive at winters and springs, and D. repleta group at both seasons. The exotic species D. simulans Sturtevant, 1919 (from D. melanogaster group) and Zaprionus indianus Gupta, 1970 were most abundant at summers. Overall, the assemblage structure did not show the same characteristics of forested or urban environments, but was similar to the forests at winters and to cities at summers. This raises the question that this locality may already been under urbanization impact. Also, this can be interpreted as an easily invaded site for exotic species, what might lead to biotic homogenization and therefore can put in check the usage of drosophilid assemblages as bioindicators at open environments.

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Litargus tetraspilotus LeConte, 1856 was collected feeding on Oidium sp. (Fungi, Ascomycota, Erysiphaceae) associated with fruit trees. This is the first time L. tetraspilotus is recorded in Brazil, totaling three species of Mycetophagidae for this country. This study aims to provide a complementary description of this species based on new characters and to present information on its life cycle under laboratory conditions and fluctuation in population in the field. During the period of inventories between July 2004 and August 2006, about every fifteen days, a total of 565 specimens of L. tetraspilotus were collected, with the highest abundance found on citrus plants, with values differing significantly between the two years. The population levels differed between the seasons; spring had the greatest abundance and autumn the least. There was a significant positive correlation of L. tetraspilotus abundance with rainfall and relative humidity. Mycetophagidae, as well as other mycophagous families of Brazilian coleopterans, are barely studied, warranting further future studies of their bioecology and systematics.

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This study has been carried out at the central region of the Araguaia river on the border between the states of Goiás and Mato Grosso in the Brazilian Amazon Basin from September to December 2000. We recorded temperature fluctuation, clutch-size, incubation period and hatching success rate and hatchlings' sex ratio of five nests of Podocnemis expansa (Schweigger, 1812). Despite the relatively small sample size we infer that: a) nests of P. expansa in the central Araguaia river have a lower incubation temperature than nests located further south; however, incubation period is shorter, hatching success rate is lower and clutch-size is larger; b) Podocnemis expansa may present a female-male-female (FMF) pattern of temperature sex-determination (TSD); c) thermosensitive period of sex determination apparently occur at the last third of the incubation period; and, d) future studies should prioritize the relationship between temperature variation (i.e., range and cycle) and embryos development, survivorship and sex determination.