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Environmental Science and Pollution Research - The conservation of ancient paintings sited in humid environments is an actual challenge for restorers, because it needs the knowledge of the...  相似文献   
53.
Environmental Science and Pollution Research - Exposure to air pollution during physical exercise is a health issue because fine particulate matter (dimension < 10 μm; PM10) includes...  相似文献   
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ABSTRACT: This paper considers the problem of forecasting the discharge time series of a river by means of a chaotic approach. To this aim, we first check for some evidence of chaotic behavior in the dynamic by considering a set of different procedures, namely, the phase portrait of the attractor, the correlation dimension, and the largest Lyapunov exponent. Their joint application seems to confirm the presence of a nonlinear deterministic dynamic of chaotic type. Second, we consider the so‐called nearest neighbors predictor and we compare it with a classical linear model. By comparing these two predictors, it seems that nonlinear river flow modeling, and in particular chaotic modeling, is an effective method to improve predictions.  相似文献   
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Treatments with ethylenediurea (EDU) protect plants from ozone foliar injury, but the processes underlying this protection are poorly understood. Adult ash trees (Fraxinus excelsior), with or without foliar ozone symptoms in previous years, were treated with EDU at 450ppm by gravitational trunk infusion in May-September 2005 (32.5ppmh AOT40). At 30-day intervals, shoot growth, gas exchange, chlorophyll a fluorescence, and water potential were determined. In September, several biochemical parameters were measured. The protective influence of EDU was supported by enhancement in the number of leaflets. EDU did not contribute its nitrogen to leaf tissue as a fertiliser, as determined from lack of difference in foliar N between treatments. Both biochemical (increase in ascorbate-peroxidase and ascorbic acid, and decrease in apoplastic hydrogen peroxide) and biophysical (decrease in stomatal conductance) processes regulated EDU action. As total ascorbic acid increased only in the asymptomatic trees, its role in alleviating O(3) effects on leaf growth and visible injury is controversial.  相似文献   
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Environmental Fluid Mechanics - The Eulerian–Lagrangian model ORSA2D_WT is employed for the simulation of uncongested wood transport, with reference to a field experiment that studied the...  相似文献   
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Sediment samples of different strata (0-3 and 12-15 cm) were collected between 1990 and 1992 during seasonal cruises in the Northern Adriatic Sea. A complete mapping of the Sr-90, Cs-137, Pu-238 and Pu-239(240) concentrations was obtained for samples covering a wide area, stretching from the Gulf of Trieste towards the Ancona shoreline. Sr-90 concentrations varied between 1.5 and 6.5 Bq kg-1 dw, Cs-137 was in the range 0.9-38.9 Bq kg-1 dw, Pu-239(240) in the range 0.08-1.5 Bq kg-1 dw and Pu-238 around 0.03 Bq kg-1 dw. Special reference was also put on the comparison between the off-shore environment and data obtained from samples collected inside the Po river delta. in spite of the major accumulation of Cs-137 inside the estuarine environment, higher concentrations of strontium and plutonium isotopes were detected in the offshore environment.  相似文献   
58.
ABSTRACT: Annual maximum daily rainfall data from nine stations throughout the southern slopes of the Eastern Italian Alps with record length of 67–68 years have been analyzed with the aim of verifying if their internal structure justifies the assumption of independence and identical distribution, or the “White noise hypothesis.” The approach is to consider the hypothesis H0 of white noise as the intersection of several sub-hypotheses, each concerning one of the characteristics of a white noise process. To this end the nine series were subjected to various statistical tests regarding randomness, independence, change-points, and predictability. The results are examined first individually and then globally. They indicate that in eight of the nine considered time series the “white noise hypothesis” was rejected.  相似文献   
59.
基于最新的TROPOMI反演的对流层NO2垂直柱浓度数据,利用Google Earth Engine平台分析了粤港澳大湾区近2a对流层NO2垂直柱浓度的分布及变化特征.结果表明, TROPOMI传感器反演的对流层NO2垂直柱浓度与地表NO2浓度监测值具有较好的相关性,反演产品能够反映地面真实的NO2污染状况;粤港澳大湾区NO2柱浓度分布呈现出较为显著的圈层结构,高NO2柱浓度区域面积约为4468km2,占大湾区总面积的8%,低NO2柱浓度地区的面积约为25331km2,占比超过了45%;大湾区上空的对流层NO2垂直柱浓度存在明显的“冬高夏低,春秋过度”的季节性差异和周期性波动特征;影响因子回归模型结果表明人类活动强度(DNB,夜间灯光)、植被状况(NDVI,植被指数)和地形因子(DEM,数字高程)与地区对流层NO2垂直柱浓度的分布有明显的相关性.本研究成果可为政府和决策者制定相关政策和措施提供借鉴.  相似文献   
60.
A coupled model of biological and settling phases aimed at optimal design of predenitrification systems is presented. Each unknown is obtained in explicit form, and is expressed as a function of the system's required performance. A model, taking into account both suspended and dissolved substrates, is adopted for the biological phase, while the limiting solid flux theory is assumed for the design of the settling phase. Finally, a relationship correlating the two phases is obtained expressing opportunely the sludge recycle flow and the sludge waste flow, without recourse to empirical parameters. The effect of different influent and effluent wastewater characteristics on the model's results is also analyzed.  相似文献   
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