上海地区SO2污染现状和趋势分析

根据上海市监测系统长期监测资料，对上海地区大气中ＳＯ２的污染现状进行了综合分析，并总结出ＳＯ２的时空分布规律与特征。应用秩相关系数法，对１９８６￣１９９５年的１０年ＳＯ２浓度均值进行了年际变化趋势检验，同时从最大值、超标率及高浓度日出现天数等不同的侧面，进行了年际变化趋势分析，以充分的证明表明，上海市ＳＯ２年际变化呈显著下降趋势。     

模糊综合评价法在水质变化和水体管理中的应用

应用模糊数学中的模糊综合评价法，对徐州市的地面水体的水质变化趋势进行了探讨，结果表明模糊综合评价法能及时发现水质恶化现象，对水体的管理具有指导作用．     

上海市土壤中人工放射性水平调查及评价

调查了１９８９－１９９０年上海市土壤中及黄浦江水系底泥中，人工放射性核素的含量。调查共设３２个点，结果表明，上海市土壤中的人工放射性核素含量，＾９０Ｓｒ、＾１３７Ｃｓ、总β的比活度均值分别为２、４１±０．７８、３．１４±１．４７、７１７．０±１３５．９Ｂｑ／ｋｇ，属正常本底水平。土壤中人工放射性核素的比活度在全市范围内分布没有明显差别，波动范围不大。土壤中＾１３７Ｃｓ的比活度比＾９０Ｓｒ高，这与土     

苏州河氨化菌分布及生理生化研究

对苏州河氨化菌进行了生态调查,并对其进行了生理生化分析。研究结果表明,苏州河水体中氨化菌数量普遍较高,上游至下游氨化菌数量逐步增多。赵屯至北新泾5个断面之间的差异很小,均在104个/mL左右,浙江路桥和武宁路桥的氨化菌数量要比上游的5个断面高出1个数量级。苏州河下游武宁路桥和浙江路桥断面水体中全年氨化菌数量季节变化较大。氯化菌的数量与水体中总氮和氨氮成正比,与硝酸盐成反比。     

上海市市区、郊区NO2、SO2和PM10的时空变化规律及相关性分析

在对上海市嘉定区大气污染物SO2、NOx和PM10连续1年的观测基础上，结合上海环境状况公报的数据，探讨了市区、郊区大气污染物的空间和时间变化规律。结果表明，2005年中NO2、SO2和PM10的质量浓度在市区和郊区均是冬春两季高，夏秋两季低；NO2、SO2和PM10浓度在市区要高于郊区；郊区大气污染物的月变化幅度要比市区大，市区PM10污染有增加趋势。根据气象条件分析，嘉定区周边工业污染对NO2、SO2和PM10的浓度有贡献，市区NO2、SO2和PM10的质量浓度则与机动车尾气、工业燃煤，建筑扬尘和道路扬尘等诸多因素有关。相关性分析表明，上海市NO2、SO2和PM10相互之间存在比较强的相关性。     

沈阳区域环境空气中一氧化氮与二氧化氮时空分布规律

以沈阳区域环境空气监测分析结果为依据 ,分析了 1 994～ 1 998年内空气中一氧化氮与二氧化氮时空分布状况及其变化趋势     

Why is competition more intense if food is supplied more slowly?

We investigated competition for food among two groups of six clone amagos (salmonids), Oncorhynchusmasoumacrostomus, in a laboratory experiment with different rates of food input. We examined the effect of temporal clumping of food resources on the inequality of food sharing between competitors. Monopolization of food by dominants was greater at a low input rate (one food item per 10 s) than at a high input rate (1 food item per 1 s). Aggressive behavior by dominants was more frequent at the low input rate than at the high input rate; its purpose was presumably to interfere with the feeding behavior of subordinates. We assessed the relative importance of three foraging factors (the number of approaches to food items, the chance per approach and the gain per chance) in enhancing inequality in food gain between individuals. Dominants had a disproportionately high chance per approach and gain per chance at the low input rate, but not at the high input rate. The chance of obtaining a food item per approach depended on how many competitors approached simultaneously. The gain per chance depended on the competitive ability of the approaching fish. There was an interaction between these components, such that the number of approaches affected the chance per approach and gain per chance. We evaluated the independent effect of the chance per approach, and showed that it was higher for dominants than for subordinates at the low input rate, but not at the high input rate. This implies that subordinates changed their behavior and became more likely to avoid approaching food at the same time as dominants at the low input rate. Received: 13 August 1996 / Accepted after revision: 30 November 1996     

Analysis of the long-term behavior of solute transport with nonlinear equilibrium sorption using breakthrough curves and temporal moments

We analyzed the long-term behavior of breakthrough curves (BTCs) and temporal moments of a solute subjected to Freundlich equilibrium sorption (s = kc(n)). For one-dimensional transport in a homogeneous porous medium, we derived a power-law relation between travel time, tau, and solute displacement, chi, with the exponent being equal to the Freundlich n exponent. The mean solute velocity, derived from the first time moment, was found to change as tau(n-1). For n values larger than 0.66, the second time moment could be related to c chi(2/n), where c is a constant. An approach based on the use of a critical concentration was developed to estimate the presence of the asymptotic regime in the tail of the BTC. This approach was tested successfully using numerical case studies. One-dimensional numerical simulations with varying values of k, n and initial mass were run to verify the closed form analytical expressions for the large time behavior of temporal moments and the tailing part of breakthrough curves. Good agreement between the slope of the tailing part of log-log transformed BTCs and the predicted slope using asymptotic theory was found. Asymptotic theory in general underestimated the magnitude of the concentration in the tail. The quality of the estimated concentrations in the tail improved for small values of the dispersivity. Experimental BTCs of uranin and benazolin were analyzed in combination with sorption/desorption batch experiments using asymptotic theory. A good agreement between the value of n parameter derived from desorption experiment with benazolin and the value of the n parameter derived from the tail of the BTC was found.     

Temporal variability of bioavailable Cd,Hg, Zn,Mn and Al in an upwelling regime

Monthly variability of Cd, Hg, Zn, Mn and Al concentrations in mussels (Mytilus californianus) soft tissue and brown seaweed (Macrocystis pyrifera) was studied at a pristine rocky shore off San Quintin Bay, Baja California, México. The results were related to climatic and hydrographic conditions and to the physiological state of the mussels (condition index) by correlation analysis and principal component analysis (PCA). A "normalization" to account for the variability induced by the physiological state of the mussel was performed. The PCA was performed in two ways to relate the environmental variables and the condition index to: (1) the metal concentrations in mussels, and (2) the "normalized" mussel concentrations. The association of the variability of Cd with the upwelling season was revealed in both PCAs. The temporal variability of this metal in mussels was highly correlated to that in seaweed, suggesting that the dissolved phase determined the variability of Cd in mussels. However, for Hg, Zn, Mn and Al the results from both PCAs were different. The first PCA showed the relationship of these metals to pluvial precipitation and to the condition index. The PCA for the normalized mussel concentrations showed that, after eliminating the effect of the condition index, only Al was related to pluvial precipitation. Manganese, and to a less degree Zn, were related to these metals in seaweed. Because zinc is an essential element in mussels, some regulation of their internal concentrations is likely. Mercury was not detected in seaweed, but because of its reactive nature, it is not expected that the dissolved fraction could be a significant pathway; therefore, it can be concluded that its temporal variability was determined by the variability in the condition index only.     

Regulation of honey bee division of labor by colony age demography

The age at which worker honey bees begin foraging varies under different colony conditions. Previous studies have shown that juvenile hormone (JH) mediates this behavioral plasticity, and that worker-worker interactions influence both JH titers and age at first foraging. These results also indicated that the age at first foraging is delayed in the presence of foragers, suggesting that colony age demography directly influences temporal division of labor. We tested this hypothesis by determining whether behavioral or physiological development can be accelerated, delayed, or reversed by altering colony age structure. In three out of three trials, earlier onset of foraging was induced in colonies depleted of foragers compared to colonies depleted of an equal number of bees across all age classes. In two out of three trials, delayed onset of foraging was induced in colonies in which foragers were confined compared to colonies with free-flying foragers. Finally, in three out of three trials, both endocrine and exocrine changes associated with reversion from foraging to brood care were induced in colonies composed of all old bees and devoid of brood; JH titers decreased and hypopharyngeal glands regenerated. These results demonstrate that plasticity in age-related division of labor in honey bee colonies is at least partially controlled by social factors. The implications of these results are discussed for the recently developed ‘‘activator-inhibitor” model for honey bee behavioral development. Received: 8 November 1995/Accepted after revision: 10 May 1996