DETERMINISTIC MODELS FOR PREDICTING RESIDENTIAL WATER CONSUMPTION1

ABSTRACT: Forecasts of future urban water demand traditionally have been made by the projection of historic trends in per capita consumption and population. This paper outlines the use of two deterministic models to forecast the residential component of urban water demand. The models incorporate specific representation of the activities which result in water consumption at each residence. Predictions of water use can then be made by modeling the changes expected in the number of these activities and the consumption for each such activity.     

Influence of weak electric and magnetic fields on turning behavior in elvers of the American eel Anguilla rostrata

The turning behavior of elvers of the American eel Anguilla rostrata was studied in an arena in which a horizontal electric or a vertical magnetic field could be manipulated. The objectives were to determine if the strength and polarity of a weak direct-current (dc) electric field influenced elver orientation, and to determine if any such influence was due to electric fields generated by the elvers' own swimming movements. As electric current density increased from 10^-2 A cm^-2 to 10² A cm^-2, elvers turned increasingly more toward the anode, regardless of whether the anode was on the left or right side of the arena. Elvers in the lowest field turned more toward the cathode than control elvers, and elvers in the highest field turned more toward the anode than controls. There were no differences in mean turning angles of groups of elvers swimming in four different vertical magnetic field conditions (0.54 gauss, <0.02 gauss, 0.52 gauss reversed direction, and 2.00 gauss), suggesting that elvers were not influenced by internally generated electric fields. However, swimming speeds were such that the generated fields would have been of the order of 10^-4 A cm^-2 or less. Elver orientation apparently could be influenced by electric fields of the magnitude generated in major ocean current systems, but probably are not influenced by electric fields generated by their own swimming in the geomagnetic field.     

Magneto-biomonitoring of intra-urban spatial variations of particulate matter using tree leaves

Preliminary mineral magnetic results from a pilot project investigating the suitability of roadside tree leaves as depositories of vehicular pollution are presented. Tree leaf surfaces (Lime: Tilia europaea; Sycamore: Acer pseudoplatanus) at four roadside and one woodland location in Wolverhampton, UK, have been monitored (July 2003 to November 2003). Mineral magnetic technologies have revealed spatial variations of particulate pollution concentration throughout the conurbation and data analysis indicates that magnetic concentration parameters are suitable proxies for fine particulate pollution, which are particularly hazardous to health. Site-specific traffic management and associated vehicle behaviour appear to be chiefly responsible for the magnetic concentration differences between sites. Magneto-biomonitoring in this way allows the high-resolution spatial mapping of particulate matter (PM) pollution, which may also benefit epidemiology in better assessing exposure to vehicular-derived particulates. Given the speed, measurement sensitivity and non-destructive nature of the technique, it is proposed that this low-cost approach offers some advantages over centralised monitoring stations to monitor urban roadside particulate pollution.     

1999年委内瑞拉阿维拉山北坡入海型泥石流

委内瑞拉阿维拉山呈东一西走向，北坡濒临加勒比海．１９９９年１２月１６日，阿维拉山北坡２０多条沟谷暴发泥石流，使沿海的城镇、村庄、港口、公路及各种设施遭到毁灭性破坏，造成数万人死亡，直接经济损失超过刀亿美元．泥石流发生在森林植被良好的山区，具低频率和群发性特征，规模大，直接入海．分析这次泥石流灾害，对我国的防灾减灾工作具有启示意义．     

脉冲放电烟气脱除尘与除SO_2和NO_X的研究

对脉冲放电烟气除尘与脱除ＳＯ２和ＮＯＸ进行实验研究与分析的结果表明，烟气中的飞灰对ＳＯ２和ＮＯＸ吸附脱除２％～５％，吸附脱除量随着飞灰浓度和烟气含量的增加而增大。在单位体积烟气注入能量为４Ｗｈ／Ｎｍ３和烟气在反应器中停留时间小于３秒，飞灰与水蒸气的协同作用使ＳＯ２和ＮＯＸ脱除率分别达到２３％和３３％。同时，脉冲放电使反应器对飞灰具有良好的协同作用，收集效率为９７％。     

车用三效催化转化器发展概况

从载体及三效催化剂角度论述了车用三效催化转化器的发展；指出了影响车用三效催化转化器性能的因素，这些因素的作用是协同的；为提高催化转化器的性能，必须采用系统的方法对其进行优化设计。     

Detection and decision-making in environmental effects monitoring

The majority of environmental effects monitoring (EEM) frameworks that have been proposed compare selected indicator variables as a means of assessing whether significant changes in stressed ecosystems have occurred. Most are deterministic in nature and do not appropriately account for the natural variability and dynamics within the systems being comapred. This suggests that the comparative procedures should be statistically based and immediately raises the issue of whether the selected comparative procedures are to be used as decision-making tools or conclusive procedures. Conclusive procedures require a significant body of evidence before rejecting the postulated null hypothesis. The costs and time involved in environmental data collection accordingly bias action toward the maintenance of a status quo approach to environmental management. if, however, EEM is treated as a decision-making procedure, risk functions that include consideration of type I and II statistical error may be developed and combined with costs to select a minimum expected loss strategy for environemental management. Examples of the interpretative difficulties and conclusion reversal phenomena caused when EEM is used as a conclusive procedure are presented. In addition, risk functions appropriate for environmental management within an EEM context are constructed and applied. Only when such tools are fully developed and applied can EEM expect to have significant impacts on minimizing environmental degradation.     

Visitor impact on backcountry campsites in the Great Smoky Mountains

Over the last decade the Great Smoky Mountains National Park (GSMNP) has experienced a tremendous increase in visitation, especially in backcountry camping. In 1976 there were an estimated 117,500 backcountry visitor nights, with a peak of 16,865 visitor nights in April. The high use season extends from March to October. Visitation tends to be concentrated in certain sections of the park and at specific sites. The Appalachian Trail, which includes about 8 percent of the maintained trail mileage, carried 32 percent of the visitor nights in 1976.Campsite disturbance is also concentrated in specific sites and sections of the park. Maximum camping disturbance per km of maintained trail was 3,400 m² for the sites on the Appalachian Trail. Shelter sites have more visitation per site and more total disturbance per site than open campsites, but shelters tend to have less intensive disturbance, such as bare soil, because they concentrate trampling impacts. Visitation levels were strongly correlated with disturbances such as bare soil at open campsites. Visitation was significantly correlated to the number of firepits at shelter sites but not to other types of disturbance. Regressions indicate that for each additional visitor night at a site (annual average), one can expect an additional 9 m² of total disturbance and 1 m²of bare soil. The distance of a site from the nearest road was not significantly correlated with damage or visitation. Elevation was correlated to visitation levels, especially in the case of the shelters. More legal sites and large illegal sites are in mesic forest types. Illegal camping accounted for 10 percent of the total camping disturbance.The data imply that the suggested removal of shelters will require redistribution of visitor use or replacement developments, such as tent platforms, in order to mitigate damage. Zone camping is a possible alternative but presents difficulties because campers may concentrate in certain plant communities and topographic positions.     

Metabolic scaling,buoyancy, and growth in larval Atlantic menhaden,Brevoortia tyrannus

We measured growth of larval Atlantic menhaden, Brevoortia tyrannus in terms of mass, volume, and weight in water as well as the mass-specific activities of the metabolic enzymes citrate synthase, lactate dehydrogenase, and malate dehydrogenase. Weight in water, the force the fish must exert to maintain vertical position, increases by a factor of 18 in larvae growing from 10 to 15 mm. The weight increase coincides with the development of the larval swim bladder. The activities of all three enzymes per unit mass of fish tissue decline greatly over this time period, indicating that the fish does not further develop its aerobic and anaerobic metabolic capacity for swimming during this growth interval.