FLOODPLAIN DELINEATION: AN ECONOMIC APPROACH1

ABSTRACT: Errors inherent in the conputation of water surface profiles are magnified by the shallow lateral slopes typical of most flood-plains, producing significant floodplain mapping errors. An economic optimization procedure which weighs the cost of overstating the location of a floodplain boundary against the cost of understanding the location provides a means for establishing the boundary location. In most cases the cost of overstating the boundary location exceeds the cost of understating the location by several magnitudes so that the boundary location should coincide with the minimum water surface elevation which would be expected to result from a flood of specified recurrence interval.     

PREDICTING INSTANTANEOUS PEAK DEMAND IN RURAL DOMESTIC WATER SUPPLY SYSTEMS1

ABSTRACT: Many rural areas of the United States still have no public domestic water systems. Typical land use patterns in these areas may require 1/2 mile or more of pipe per farm connection. Public systems serving these areas are economically feasible only if realistic short-term peak demand standards are available for their design. The lack of reliable data upon which to establish such criteria has resulted in a large variation in criteria among state and federal agencies involved in financing and in approving construction of these systems. During the summer of 1975 three distribution laterals of a rural system in Utah were master metered and instantaneous peak flows were recorded for 4 months. The metered lines served 4, 12, and 22 farm houses each. The frequency distribution of peak flows has been analyzed and compared with that developed during similar research in Mississippi and with the existing design standards of the Farmers Home Administration and the State of Utah.     

Economic rent : Incidence in selected metals and minerals

The magnitude of the ‘economic rent’ and its distribution among producing countries, mineral exploitation companies and consumers has become a dominant issue in national and international policy formulation, but the difficulties in measuring the rent add to the problems of determining its equitable distribution. This paper examines the nature of the rent and estimates its incidence in bauxite, copper, iron ore, phosphate rock, tin and petroleum. Rents were found to be low for bauxite and iron ore. Bauxite, phosphates and petroleum producers have increased their share of the rent, though this trend now seems to be reversing for bauxite and phosphates. Only in tin, and to a lesser extent petroleum, have the exporting countries captured significant shares in total rent. Otherwise, the rent is largely concentrated at the processing stage, which suggests that processing plant would have to shift to the producing countries if they are to claim a larger share.     

Evidence for differential selection and potential adaptive evolution in the worker caste of an inquiline social parasite

Social parasites exploit the socially managed resources of social insect colonies in order to maximise their own fitness. The inquilines are among the most specialised social parasites, because they are dependent on being fully integrated into their host's colony throughout their lives. They are usually relatives of their host and so share ancestral characteristics (Emery's rule). Closely related inquiline-host combinations offer a rare opportunity to study trade-offs in natural selection. This is because ancestral adaptations to a free-living state (e.g. the production of a worker caste) become redundant and may be replaced by novel, parasitic traits as the inquiline becomes more specialised. The dynamics of such processes are, however, unknown as virtually all extant inquiline social parasites have completely lost their worker caste. An exception is Acromyrmex insinuator, an incipient permanent social parasite of the leaf-cutting ant Acromyrmex echinatior. In the present study, we document the size distribution of parasite and host workers and infer how selection has acted on A. insinuator to reduce, but not eliminate, its investment in a worker caste. We show that the antibiotic producing metapleural glands of these parasite workers are significantly smaller than in their host counterparts and we deduce that the metapleural gland size in the host represents the ancestral state. We further show experimentally that social parasite workers are more vulnerable to the general insect pathogenic fungus Metarhizium than are host workers. Our findings suggest that costly disease resistance mechanisms are likely to have been lost early in inquiline evolution, possibly because active selection for maintaining these traits became less when parasite workers had evolved the ability to exploit the collective immune system of their host societies.     

WATER DEMAND AT WESTERN U.S. RECREATION DEVELOPMENTS1

Although the volume of potable water used at recreation developments is minor relative to total regional water use, very high quality is required and the source is often of limited capacity, such as a mountain spring or small local aquifer. Frequent confrontations between developers and regulatory agencies result from claims by developers that water demand will be very small while regulators tend to treat such developments the same as municipal residence. Almost no published data base exists for resolving such conflicts. Included here are: 1) Water use measurements of various peak period durations (seasonal, monthly, daily, and instantaneous) at several types of recreational developments in Utah and Wyoming (mountain cabins, both ski- and water-based condominiums, and recreation vehicle campgrounds), 2) statistical (frequency) analysis of the data and a comparison with municipal demands in the same region, and 3) analysis of occupancy rates at the various categories of developments.     

Characteristics of winter backcountry use in Great Smoky Mountains National Park

Numerous backcountry and wilderness use studies have been conducted over the last decade, but nearly all of them have concentrated on peak season and summer use. This study investigates use patterns and user characteristics of winter campers, and implications for the management of winter backcountry overnight use. Use pattern data were collected from 580 backcountry use permits for both winter and summer campers of Great Smoky Mountains National Park (GSMNP). A two-page questionnaire was also mailed to 300 of the winter users to survey their characteristics, past backpacking experience, and reasons for winter camping. Backcountry permit data indicate that use patterns differ significantly between winter and summer campers, with winter campers taking shorter, weekend, destination-type trips. Winter campers engage in backcountry camping nearly twice as often during winter as other seasons of the year, both in and outside GSMNP. They are also experienced hikers that tend to avoid camping in Great Smoky Mountains National Park during the summer because of heavy visitor use. This suggests that winter backcountry campers are different enough from peak season campers that management of these two user groups may require different styles.     

城市噪声对校园的干扰类型与特征浅析

对阿图什市区各学校所受的周边环境噪声干扰情况进行了监测，运用声环境评价方法，将市区10所学校校园划分为清静型、扰闹型和持续吵闹型3种噪声干扰类型。分析了各类型的特征和成因，并提出防治措施。     

Influence of ozone air pollution on plant-herbivore interactions. Part 1: Biochemical changes in ornamental milkweed (Asclepias curassavica L.; asclepiadaceae) induced by ozone

A series of fumigation experiments was conducted with bloodflower (Asclepias curassavica L.) in continuous-flow stirred reactors (CSTRs) to elucidate the effects of ozone on foliar concentrations of several primary and secondary plant metabolites relevant to herbivores. Plants 8 weeks of age were subjected to different ozone levels ranging from 0 to 134 nl liter(-1) for exposure periods up to 16 days. Leaves were analyzed for concentration of soluble carbohydrates, starch, free amino acids, soluble protein, total phenolics, and total cardenolides. Significant interactions between the linear effects of ozone concentration and exposure time were found for soluble carbohydrates, amino acids, cardenolides and phenolics. No significant treatment effects could be observed on foliar starch and protein concentration. The metabolic responses of plants to fumigation appeared to be altered by overall plant nutrition. It is possible that the metabolic changes observed in the host plant represent important changes in nutritional quality to insects.