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191.
R. A. Machado M. L. Brizot M. H. B. Carvalho A. L. Waissman V. Bunduki M. Zugaib 《黑龙江环境通报》2005,25(1):31-33
We report two cases of exencephaly diagnosed by transvaginal ultrasonography at 8 weeks 4 days and at 9 weeks 3 days of gestation. Both cases presented an irregular cephalic pole, and, in the case seen at 8 weeks 4 days, brain vesicles were also absent, whereas in the case seen at 9 weeks 3 days, the midline echo was indistinguishable with disorganized choroid plexuses. In both cases, anencephaly was evident at 11 and 12 weeks' gestation and the postmortem confirmed the diagnosis. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
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193.
A suspended-growth bioreactor (SGB) was operated for the treatment of a gaseous stream mimicking emissions generated at a leather industrial company. The main volatile organic compounds (VOCs) present in the gaseous stream consisted of 1-methoxy-2-propanol, 2,6-dimethyl-4-heptanone, 2-butoxyethanol, toluene and butylacetate. A microbial consortium able to degrade these VOCs was successfully enriched. A laboratory-scale SGB was established and operated for 210-d with an 8h cycle period and with shutdowns at weekends. Along this period, the SGB was exposed to organic loads (OL) between 6.5 and 2.3 x 10(2) g h(-1) m(-3). Most of the compounds were not detected at the outlet of the SGB. The highest total VOC removal efficiency (RE) (ca 99%) was observed when an OL of 1.6 x 10(2) g h(-1) m(-3) was fed to the SGB. The maximum total VOC elimination capacity (1.8 x 10(2) g h(-1) m(-3)) was achieved when the OL applied to the SGB was 2.3 x 10(2) g h(-1) m(-3). For all the operating conditions, the SGB showed high levels of degradation of toluene and butylacetate (RE approximately equal to 100%). This study also revealed that recirculation of the gaseous effluent improved the performance of the SGB. Overall, the SGB was shown to be robust, showing high performance after night and weekend shutdown periods. 相似文献
194.
Carvalho FP 《Journal of environmental radioactivity》2011,102(5):462-472
The determination of 210Po and 210Pb was performed in marine organisms from the seashore to abyssal depths, encompassing a plethora of species from the microscopic plankton to the sperm whale. Concentrations of those radionuclides ranged from low values of about 5 × 10−1 Bq kg−1 (wet wt.) in jellyfish, to very high values of about of 3 × 104 Bq kg−1 (wet wt.) in the gut walls of sardines, with a common pattern of 210Po > 210Pb.These radionuclides are primarily absorbed from water and concentrated by phyto- and microzooplankton, and then are transferred to the next trophic level along marine food chains. Investigation in epipelagic, mesopelagic, bathypelagic and abyssobenthic organisms revealed that 210Po is transferred in the marine food webs with transfer factors ranging from 0.1 to 0.7, and numerically similar to those of the energy transfer in the marine food chains. As 210Po preferentially binds to amino acids and proteins, its transfer in food chains likely traces protein transfer and, thus, 210Po transfer factors are similar to ecotrophic coefficients. 210Pb is transferred less efficiently in marine food chains and this contributes to increased 210Po:210Pb activity ratios in some trophic levels. 相似文献
195.
Ability of salt marsh plants for TBT remediation in sediments 总被引:1,自引:1,他引:0
Pedro N. Carvalho M. Clara P. Basto Manuela F. G. M. Silva Ana Machado A. A. Bordalo M. Teresa S. D. Vasconcelos 《Environmental science and pollution research international》2010,17(6):1279-1286
Introduction
The capability of Halimione portulacoides, Spartina maritima, and Sarcocornia fruticosa (halophytes very commonly found in salt marshes from Mediterranean areas) for enhancing remediation of tributyltin (TBT) from estuarine sediments was investigated, using different experimental conditions. 相似文献196.
C. Borrego A. Monteiro J. Ferreira M.R. Moraes A. Carvalho I. Ribeiro A.I. Miranda D.M. Moreira 《Atmospheric environment (Oxford, England : 1994)》2010,44(3):370-380
The main purpose of this study is to evaluate the photochemical pollution over the Metropolitan Area of Porto Alegre (MAPA), Brazil, where high concentrations of ozone have been registered during the past years. Due to the restricted spatial coverage of the monitoring air quality network, a numerical modelling technique was selected and applied to this assessment exercise. Two different chemistry-transport models – CAMx and CALGRID – were applied for a summer period, driven by the MM5 meteorological model. The meteorological model performance was evaluated comparing its results to available monitoring data measured at the Porto Alegre airport. Validation results point out a good model performance. It was not possible to evaluate the chemistry models performance due to the lack of adequate monitoring data. Nevertheless, the model intercomparison between CAMx and CALGRID shows a similar behaviour in what concerns the simulation of nitrogen dioxide, but some discrepancies concerning ozone. Regarding the fulfilment of the Brazilian air quality targets, the simulated ozone concentrations surpass the legislated value in specific periods, mainly outside the urban area of Porto Alegre. The ozone formation is influenced by the emission of pollutants that act as precursors (like the nitrogen oxides emitted at Porto Alegre urban area and coming from a large refinery complex) and by the meteorological conditions. 相似文献
197.
A. Carvalho A. Monteiro I. Ribeiro O. Tchepel A.I. Miranda C. Borrego S. Saavedra J.A. Souto J.J. Casares 《Atmospheric environment (Oxford, England : 1994)》2010,44(8):1020-1031
Each summer period extremely high ozone levels are registered at the rural background station of Lamas d'Olo, located in the Northeast of Portugal. In average, 30% of the total alert threshold registered in Portugal is detected at this site. The main purpose of this study is to characterize the atmospheric conditions that lead to the ozone-rich episodes at this site. Synoptic patterns anomalies and back trajectories cluster analysis were performed, for the period between 2004 and 2007, considering 76 days when ozone maximum hourly concentrations were above 200 μg m?3. The obtained atmospheric anomaly fields suggested that a positive temperature anomaly is visible above the Iberian Peninsula. A strong wind flow pattern from NE is observable in the North of Portugal and Galicia, in Spain. These two features may lead to an enhancement of the photochemical production and to the transport of pollutants from Spain to Portugal. In addition, the 3D mean back trajectories associated to the ozone episode days were analysed. A clustering method has been applied to the obtained back trajectories. Four main clusters of ozone-rich episodes were identified, with different frequencies of occurrence: north-westerly flows (11%); north-easterly flows (45%), southern flow (4%) and westerly flows (40%). Both analyses highlight the NE flow as a dominant pattern over the North of Portugal during summer. The analysis of the ozone concentrations for each selected cluster indicates that this northeast circulation pattern, together with the southern flow, are responsible for the highest ozone peak episodes. This also suggests that long-range transport of atmospheric pollutants is the main contributor to the ozone levels registered at Lamas d'Olo. This is also highlighted by the correlation of the ozone time-series with the meteorological parameters analysed in the frequency domain. 相似文献
198.
Application of fluidization to separate packaging waste plastics 总被引:1,自引:0,他引:1
The objective of the experimental work described in this paper is the study of the separation of PS (polystyrene) from PET (polyethylene terephthalate) and PVC (polyvinyl chloride) from drop-off points using a fluidized bed separator. This is a low-cost process commonly used in the hydro-classification of mineral ores. Firstly, experimental tests were carried out with artificial granulated samples with different grain sizes, types and sources of plastic ("separability tests"). The particle settling velocities were determined under different operating conditions. Then, based on the results, the laboratory tests continued with real mixtures of waste plastics ("separation tests") and the efficiency of the process was evaluated. From a PET-rich mixture, a concentrate of PS with a 75% grade in PS was produced while the underflow was quite clear from PS (grade less than 0.5% in PS). 相似文献
199.
200.
Valfredo Azevedo Lemos Anaildes Lago de Carvalho 《Environmental monitoring and assessment》2010,171(1-4):255-265
The analysis of human biological samples, such as blood, urine, nails, and hair, is generally used for the verification of human exposure to toxic metals. In this review, various spectrometric methods for the determination of cadmium and lead in biological samples are discussed and compared. Several spectrometric techniques are presented and discussed with respect to various characteristics such as sensitivity, selectivity, and cost. Special attention is drawn to the procedures for digestion prior to the determination of cadmium and lead in hair, nails, blood, and urine. 相似文献