422 research outputs found

    An analysis of landscape fragmentation in the Brazilian Amazon based on deforestation data derived from Landsat imagery.

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    Deforestation in the Brazilian Amazon has produced fragmentation of the largest tropical rain forest in the planet resulting in impacts over biodiversity and the functioning of ecosystems. Most of the deforestation is known to be concentrated near major roads and areas of pioneer colonization, but few studies have quantitatively analyzed patterns and processes of landscape fragmentation associated with this spatial dynamics. In this paper we evaluate the effect of forest clearing based on two landscape metrics - percent cleared and percolation - for areas in the states of Mato Grosso, Pará, and Rondônia where the largest rates of deforestation have been observed. Deforestation data included one data set derived from Landsat MSS imagery for the 1970?s and one based on Landsat TM imagery for 2006. Forest fragments in 2006 within 25-km of areas deforested since 1978 - where a large majority of recent deforestation has been concentrated - were analyzed to assess how landscape fragmentation has evolved following the diffusion of forest clearing within a relatively close neighborhood of the 1978 deforestation. The distribution of deforestation for regular ¼-degree grid cells with different values of percent cleared was estimated as a proxy for the distribution of the equivalent metric based on actual farm limits. The fractions of deforestation for larger categories of percent cleared have increased during the diffusion of forest clearing and a majority of the total 2006 deforestation belonged to areas with less than 50% of forest remnants, taking as reference the Brazilian forest regulations. The diffusion of deforestation has resulted in different patterns of landscape fragmentation based on estimated percolation and we propose an analysis of such patterns based on geographic differences

    Differentiation Between Women With Vulvovaginal Symptoms Who are Positive or Negative for Candida Species by Culture

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    Objective: To investigate whether clinical criteria could differentiate between women with vulvovaginitis who were culture positive or negative for vaginal Candida species. Methods: Vulvovaginal specimens were obtained from 501 women with a vaginal discharge and/or pruritis. Clinical information and wet mount microscopy findings were obtained. All specimens were sent to a central laboratory for species identification. Results: A positive culture for Candida species was obtained from 364 (72.7%) of the specimens. C. albicans was identified in 86.4% of the positive cultures, followed by C. glabrata in 4.5%, C. parapsilosis in 3.9%, C. tropicalis in 2.7% and other Candida species in 1.4%.Women with a positive Candida culture had an increased utilization of oral contraceptives (26.1% vs. 16.8%, p = 0.02) and antibiotics (8.2% vs. 0.7%, p = 0.001), and were more likely to be pregnant (9.1% vs. 3.6%, p = 0.04) than the culture-negative women. Dyspareunia was more frequent in women without Candida (38.0% vs. 28.3%, p = 0.03) while vaginal erythema (p = 0.01) was more common in women with a positive Candida culture. Conclusions: Although quantitative differences were observed, the presence of vaginal Candida vulvovaginitis cannot be definitively identified by clinical criteria

    Improving the Global Fitting Method on Non-Linear Time Series Analysis

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    In this paper, we are concerned with improving the forecast capabilities of the Global approach to Time Series. We assume that the normal techniques of Global mapping are applied, the noise reduction is performed, etc. Then, using the mathematical foundations behind such approaches, we propose a method that, without a great computational cost, greatly increase the accuracy of the corresponding forecasting

    Medidas morfométricas da carcaça de cordeiros de diferentes genótipos submetidos a dois sistemas de produção.

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    Resumo: Objetivou-se avaliar a influência do sistema de produção, bem como de diferentes grupos genéticos sobre as características morfométricas da carcaça de cordeiros. Foram observados 24 animais, machos não castrados, das raças ½Dorper x ½SPRD, ½Santa Inês x ½SPRD e ½Somalis x ½SPRD, submetidos à terminação a pasto e em confinamento. Os animais foram abatidos com peso vivo médio de 30 kg. As carcaças foram pesadas e refrigeradas a 4ºC por 24h, quando então foram mensuradas as seguintes medidas morfométricas: comprimento corporal, perímetro torácico, perímetro da perna, comprimento da perna e comprimento interno. O sistema de produção interferiu nas medidas de perímetro da perna e comprimento interno, não havendo diferença significativa (P>0,05) para as demais medidas. Os genótipos estudados não influenciaram na medida de perímetro. As medidas de comprimento da carcaça, perímetro da perna e comprimento interno não diferiram estatisticamente para os mestiços ½Dorper x ½SPRD e ½Santa Inês x ½SPRD, no entanto esses genótipos apresentaram diferença significativa para a raça ½Somalis x ½SPRD nesses parâmetros. O sistema de produção não acarretou mudanças importantes para as medidas morfométricas de comprimento de carcaça, perímetro torácico e comprimento da perna. O mestiço ½Dorper x ½SPRD apresentou as melhores médias para as medidas estudadas. [Morphometric carcass characteristics of lambs of different genotypes under two production systems]. Abstract: Objectified to evaluate the influence of production system, well as of different genetic groups on the morphometric characteristics of the carcass of lambs. 24 animals had been observed, males not castrated, of breeds ½ Dorper x ½ SPRD, ½ Santa Inês x ½ SPRD and ½ Somalis x ½ SPRD, submitted to termination grass and confinement. The animals had been abated with average alive weight 30 kg. The carcasses had been weighed and cooled 4ºC for 24h, when then following morphometric measures had been measured: corporal length, thoracic perimeter, perimeter of leg, length of leg and internal length. The production system intervened with the measures of perimeter of leg and internal length, not having significant difference (P>0.05) for excessively measures. Studied genotypes had not influenced in measure of perimeter. Measures of length of carcass, perimeter of leg and internal length hanot statistical differed for the mestizos ½ Dorper x ½ SPRD and ½ Santa Inês x ½ SPRD, however these genotypes had presented significant difference for the breed ½ Somalis x ½ SPRD in these parameters. The production system does not cause important changes for morphometric measures of carcass length, thoracic perimeter and length of the leg. The mestizo ½ Dorper x ½ SPRD presented best averages for studied measures
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