排序方式: 共有27条查询结果,搜索用时 15 毫秒
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Jorge A. Achcar Eliane R. Rodrigues Edilberto Cepeda-Cuervo 《Environmental Modeling and Assessment》2013,18(3):259-270
In this paper, we consider several modelling approaches for the mean time between exceedances of a given environmental threshold. The interest here resides in the time between ozone exceedances (also called ozone inter-exceedances times). The proposed models assume two basic density functions for the time between surpassings: the Weibull and the generalised exponential functions. Considering those distributions, a random effect with autoregressive structure is taken into account to determine unexpected changes in the mean of the inter-exceedances density functions. Those unexpected changes could be captured either by their scale parameter or by both their scale and shape parameters. The models are applied to ozone data from the monitoring network of Mexico City. Selection of the model that best explains the data is performed using the deviance information criterion and also the sum of the absolute values of the differences between the estimated and observed means of the inter-exceedances times. An analysis to detect the possible presence of change-points is also presented. 相似文献
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Joseane Simone de Oliveira Pereira Lidiane Rodrigues da Silva Amanda de Meireles Nunes Silas de Souza Oliveira Eliane Veiga da Costa Edson Elias da Silva 《Food and environmental virology》2016,8(1):27-33
Wild polioviruses still remain endemic in three countries (Afghanistan, Pakistan, and Nigeria) and re-emergency of wild polio has been reported in previously polio-free countries. Environmental surveillance has been used as a supplementary tool in monitoring the circulation of wild poliovirus (PVs) and/or vaccine-derived PVs even in the absence of acute flaccid paralysis cases. This study aimed to monitor the presence of polioviruses in wastewater samples collected at one wastewater treatment plant located in the municipality of Rio de Janeiro, Brazil. From December 2011 to June 2012 and from September to December 2012, 31 samples were collected and processed. RD and L20B cell cultures were able to isolate PVs and non-polio enteroviruses in 27/31 samples. Polioviruses were isolated in eight samples (type 1 Sabin = 1, type 2 Sabin = 5, and type 3 Sabin = 2). Vaccine-derived polioviruses were not detected nor evidence of recombination with other PVs or non-polio enterovirus serotypes were observed among the isolates. The Sabin-related serotypes 2 and 3 presented nucleotide substitutions in positions associated with the neurovirulent phenotype at the 5′-UTR. Changes in important Amino acid residues at VP1 were also observed in the serotypes 2 and 3. Environmental surveillance has been used successfully in monitoring the circulation of PVs and non-polio enteroviruses and it is of crucial importance in the final stages of the WHO global polio eradication initiative. Our results show the continuous circulation of Sabin-like PVs and non-polio enteroviruses in the analyzed area during the study period. 相似文献
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Andre J. Riveros Darci M. S. Esquivel Eliane Wajnberg Robert B. Srygley 《Behavioral ecology and sociobiology》2014,68(1):55-62
How animals sense, process, and use magnetic information remains elusive. In insects, magnetic particles are candidates for a magnetic sensor. Recent studies suggest that the ant Pachycondyla marginata incorporates iron-containing particles from soil. We used leaf-cutter ants Atta colombica to test whether soil contact is necessary for developing a functional magnetic compass. A. colombica is the only invertebrate known to calculate a path-integrated home vector using a magnetic compass. Here, we show that A. colombica requires contact with soil to incorporate magnetic particles that can be used as a magnetic compass; yet, we also show that ants can biosynthesize magnetic particles. Workers from a soil-free colony ignored a 90° shift in the horizontal component of the geomagnetic field, yet oriented homeward despite the occlusion of any geocentric cues. In contrast, workers from a soil-exposed colony oriented to an intermediate direction between their true and subjective home in the shifted field. Homeward orientations under shifted fields suggest that ants calculated a path-integrated vector using proprioceptive information. Strikingly, ants from the soil-free colony also had magnetic particles; yet, as observed by ferromagnetic resonance, these particles differed from those in soil-exposed ants and were not associated with a magnetic compass sensitive to this experimental manipulation. 相似文献
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A broadly defined scientific Capacity Building (CB) for Sustainable Development (SD) is needed all around the world, and the development of innovative capacities in the developing countries is a priority. For this, first we need to know how this concept is applied in some developing countries. In this paper we present some Mexican experiences in the field of capacity building for sustainable development. The main problems are the monodisciplinary training of the specialists, the absence of a sound policy for promotion, career development and assessment of researchers, as well as of their projects when they are interdisciplinary and development-oriented. The main proposals to solve these problems are the creation of mechanisms that foster and legitimize interdisciplinary work; a decentralized planning process with the specific objective of establishing the needs and orientations on a regional basis; provide resources to long-term projects, and finally, consensus on asking international funding agencies for stronger support for public higher education institutions in developing countries in order to increase and strengthen their capacity for education and research in general, and in the field of SD in particular. 相似文献
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Jorge A. Achcar Eliane R. Rodrigues Guadalupe Tzintzun 《Environmental and Ecological Statistics》2011,18(2):271-290
In this paper we make use of some stochastic volatility models to analyse the behaviour of a weekly ozone average measurements
series. The models considered here have been used previously in problems related to financial time series. Two models are
considered and their parameters are estimated using a Bayesian approach based on Markov chain Monte Carlo (MCMC) methods.
Both models are applied to the data provided by the monitoring network of the Metropolitan Area of Mexico City. The selection
of the best model for that specific data set is performed using the Deviance Information Criterion and the Conditional Predictive
Ordinate method. 相似文献
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Barros Ivaldete Tijolin Ceccon Juliana Parolin Glinski Andressa Liebel Samuel Grötzner Sonia Regina Randi Marco Antonio Ferreira Benedito Evanilde Ortolani-Machado Claudia Feijó Filipak Neto Francisco de Oliveira Ribeiro Ciro Alberto 《Environmental science and pollution research international》2017,24(19):16228-16240
Environmental Science and Pollution Research - In the current study, water quality of five river sites in Parana River basin (Brazil), utilized for public water supply, was assessed through a set... 相似文献
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Simões Eliane de Sousa Junior Wilson C. de Freitas Débora M. Mills Morena Iwama Allan Y. Gonçalves Isabel Olivato Débora Fidelman Pedro 《Regional Environmental Change》2017,17(6):1739-1750
Regional Environmental Change - This paper examines barriers and opportunities for climate change adaptation in an urban coastal setting where adaptation is in its infancy. It draws on a diagnostic... 相似文献
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Rodrigues Eliane R. Nicholls Geoff Tarumoto Mario H. Tzintzun Guadalupe 《Environmental and Ecological Statistics》2019,26(2):153-184
Environmental and Ecological Statistics - A non-homogeneous Poisson process is used to study the rate at which a pollutant’s concentration exceeds a given threshold of interest. An... 相似文献