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1.
Based on a study of Little Saigon, an ethnic enclave in Westminster, California, this paper examines the physical, social, symbolic and emotional significance of such places in the lives of immigrants. We focus on three specific aspects of the ethnic enclave: architectural elements, everyday social interaction within the enclave, and public ritual events. We highlight how the built architectural environment and the immigrants' social, commercial, and ritual activities interact to create and sustain a sense of place, foster community identity, and structure social relations. We conclude that ethnic enclaves constitute an important aspect of an immigrant's place identity enabling him/her to simultaneously remain connected to the places left behind and yet appropriating and forging significant new place ties.  相似文献   

2.
ABSTRACT: The term flashiness reflects the frequency and rapidity of short term changes in streamflow, especially during runoff events. Flashiness is an important component of a stream's hydrologic regime. A variety of land use and land management changes may lead to increased or decreased flashiness, often to the detriment of aquatic life. This paper presents a newly developed flashiness index, which is based on mean daily flows. The index is calculated by dividing the pathlength of flow oscillations for a time interval (i.e., the sum of the absolute values of day‐to‐day changes in mean daily flow) by total discharge during that time interval. This index has low interannual variability, relative to most flow regime indicators, and thus greater power to detect trends. Index values were calculated for 515 Midwestern streams for the 27‐year period from 1975 through 2001. Statistically significant increases were present in 22 percent of the streams, primarily in the eastern portion of the study area, while decreases were present in 9 percent, primarily in the western portion. Index values tend to decrease with increasing watershed area and with increasing unit area ground water inputs. Area compensated index values often shift at ecoregion boundaries. Potential index applications include evaluation of programs to restore more natural flow regimes.  相似文献   

3.
ABSTRACT: Drought management depends on indicators to detect drought conditions, and triggers to activate drought responses. But determining those indicators and triggers presents challenges. Indicators often lack spatial and temporal transferability, comparability among scales, and relevance to critical drought impacts. Triggers often lack statistical integrity, consistency among drought categories, and correspondence with desired management goals. This article presents an approach for developing and evaluating drought indicators and triggers, using a probabilistic framework that offers comparability, consistency, and applicability. From that, a multistate Markov model investigates the stochastic behavior of indicators and triggers, including transitioning, duration, and frequency within drought categories. This model is applied to the analysis of drought in the Apalachicola‐Chattahoochee‐Flint River Basin in the southeastern United States, using indicators of the Standardized Precipitation Index (for 3, 6, 9, and 12 months), the Palmer Drought Severity Index, and the Palmer Hydrologic Drought Index. The analysis revealed differences among the performance of indicators and their trigger thresholds, which can influence drought responses. Results contribute to improved understanding of drought phenomena, statistical methods for indicators and triggers, and insights for drought management.  相似文献   

4.
This article first identifies the underlying features of the supply and demand for metals responsible for market instability. These include the unresponsiveness of supply in the short term to increases in price once output approaches the limits of existing capacity, the unresponsiveness of demand in the short term to changes in price and the shifts in demand over the business cycle due to changes in income. The consequences of cyclical volatility are examined next. In some industries, market instability is reflected by frequent and sharp fluctuations in price. In others, producers set prices and keep them relatively stable. Even these industries, it is argued, suffer from cyclical volatility. The latter simply manifests itself in other ways. Finally, two developments are considered that suggest the problem of cyclical volatility may be growing more acute over time. The first concerns the willingness of metal producers, fabricators, and others to vary their inventories so that metal stocks are drawn down when consumption is relatively high and built up when consumption is down. The second development involves the trend over time in the magnitude and synchronization of business cycles in the major industrialized countries. Cet article commence d'abord par déterminer les caractéristiques de l'offre et de la demande concemant les métaux qui sont responsables de l'instabilité du marché - le manque d'élasticité de l'offre à court terme aux augmentations de prix lorsque le montant de la production approche les limites de sa capacité, le manque d'élasticité de la demande à court terme aux changements de prix et l'ajustement de la demande aux variations des revenue pendant le cycle industriel. Les conséquences de la volatilité cyclique sont examinées ensuite. Dans quelques industries, l'instabilité du marché se reflète par de fréquentes et violentes fluctuations dans les prix. Dans d'autres, les producteurs fixent les prix et les maintiennent relativement stables. Mais, même ces industries souffrent des fluctuations cycliques. Ces dernières simplement se manifestent d'autres façons. Finalement, l'article étudie deux éléments qui suggèrent que le problème des fluctuations cycliques peut devenir plus aigu avec le temps. Le premier concerne la volonté des producteurs de métaux, des transformateurs et autres d'adapter leurs inventaires de façon à ce que les stocks de métaux baissent lorsque la consommation est relativement élevée et augmentent lorsque celle-ci décroît. Le deuxième élément comprend la tendance en fonction du temps concernant l'importance et la synchronisation des cycles industriels dans les principaux pays industrialisés. Este artículo identifica primero los aspectos subyacentes en la oferta y demanda de metales que son responsables de la inestabilidad del mercado, tales como la falta de reacción de la oferta en el corto plazo al incremento de precio cuando el nivel de producción se aproxima a la capacidad límite de producción, la inelasticidad de la demanda en el corto plazo y el desplazamiento de la demanda durante el ciclo económico debido a cambios en el nivel de ingreso. Luego se examinan las consecuencias de la “volatilidad” cíclica. En algunas industrias la inestabilidad del mercado se refleja en frecuentes y bruscas fluctuaciones de precio. En otras, los productores fijan los precios y los mantienen relativamente estables. Se dice que aún en estas industrias ocurre la “volatilidad” cíclica la que se manifieste en forma distinta. Finalmente se consideran dos tendencias que sugieren que el problema de la “volatilidad” cíclica está tomándose cada vez más aguda. La primera se refiere al deséo de los productores de metales, fabricantes y otros de variar sus inventarios de manera que éstos disminuyan cuando el consumo es relativamente alto y aumenten cuando el consumo es bajo. La segunda se refiere a la tendencia que está siguiendo la magnitud y sincronización de los ciclos económicos de los principales países industrializados.  相似文献   

5.
Forest harvesting can increase solar radiation in the riparian zone as well as wind speed and exposure to air advected from clearings, typically causing increases in summertime air, soil, and stream temperatures and decreases in relative humidity. Stream temperature increases following forest harvesting are primarily controlled by changes in insolation but also depend on stream hydrology and channel morphology. Stream temperatures recovered to pre‐harvest levels within 10 years in many studies but took longer in others. Leaving riparian buffers can decrease the magnitude of stream temperature increases and changes to riparian microclimate, but substantial warming has been observed for streams within both unthinned and partial retention buffers. A range of studies has demonstrated that streams may or may not cool after flowing from clearings into shaded environments, and further research is required in relation to the factors controlling downstream cooling. Further research is also required on riparian microclimate and its responses to harvesting, the influences of surface/subsurface water exchange on stream and bed temperature regimes, biological implications of temperature changes in headwater streams (both on site and downstream), and methods for quantifying shade and its influence on radiation inputs to streams and riparian zones.  相似文献   

6.
ABSTRACT: Buffer strips are undisturbed, naturally vegetated zones around water supply reservoirs and their tributaries that are a recognized and integral aspect of watershed management. These strips can be very effective in protecting the quality of public potable water supply reservoirs by removing sediment and associated pollutants, reducing bank erosion, and displacing activities from the water's edge that represent potential sources of nonpoint source pollutant generation. As part of a comprehensive watershed management protect for the State of New Jersey, a parameter-based buffer strip model was developed for application to all watersheds above water supply intakes or reservoirs. Input requirements for the model include a combination of slope, width, and time of travel. The application of the model to a watershed in New Jersey with a recommended buffer strip width that ranges from 50 to 300 feet, depending upon a number of assumptions, results in from 6 to 13 percent of the watershed above the reservoir being occupied by the buffer.  相似文献   

7.
The City of Cape May, New Jersey, draws its primary water supply from the Cohansey Aquifer, a unit serving residential, community, and industrial users throughout the Coastal Plain. By the year 2000, projected population growth will impose a peak water demand beyond available supplies. In addition, regional over-pumping threatens the Cohansey with saltwater intrusion, placing the city wells at risk by 1998. In the early-to mid 1990s, three broad categories of water-supply alternatives were evaluated by regional, state, and federal agencies — additional pumping from the Cohansey, conjunctive use of the Cohansey with other aquifers, and desalination of brackish groundwater. An approach was adopted in 1996 which derives up to 2 MGD from desalination of brackish groundwater, with the remaining peak demand satisfied by short-term pumpage from existing wells in the Cohansey. The first of two wells has been completed, yielding 1.4 MGD of brackish groundwater. Similar performance from the second well will exceed the design goal. When the initial system comes on line during the summer of 1998, New Jersey will have its first public water supply derived from desalinated groundwater. The use of desalinated groundwater balances competing demands for water resources in the southern Cape Region of New Jersey, allowing continued economic growth while reducing human impacts on a threatened aquifer.  相似文献   

8.
ABSTRACT: This study examines the extent to which knowledge deficits pose a significant barrier to public support for nonpoint pollution management strategies. Such barriers would obtain if all of the following conditions are present: (1) many in the public lack knowledge relevant to those strategies; (2) variations in knowledge are linked only to relatively unchanging personal attributes; and (3) individuals with more knowledge are more likely to support the implementation of management strategies. Each of these conditions is subjected to empirical analysis in this study. The findings reported here derive from a survey of citizens in Spokane, Washington, the site of a major 208 Water Quality Management Program study. The results of the survey indicate that: portions of the public have enough knowledge to evaluate technically based management strategies; sources of public knowledge are sufficiently elastic that both policy area concern and policy relevant knowledge can be elevated in the short run; and both knowledge levels and general attitudes are related to the public's specific water policy preferences. The study concludes that the apparent lack of knowledge among the public is not necessarily a significant barrier to policy implementation, and that support for implementation may be generated through both knowledge enhancement and the tapping of existing political orientations through the placement of emphasis upon the seriousness of water resource problems.  相似文献   

9.
Abstract: Recognition is growing that fisheries must be both ecologically and commercially sustainable. The bioeconomic models proposed herein constitute an analytic framework capable of integrating the ethics and Societal values associated with fisheries preservation. Specifically, we focus on the normalized optimal (equilibrium) fish population, z*, a dimensionless variable representing biomass as a proportion of environmental capacity. We model z* as a function of (a) the dimensionless "bionomic growth ratio", γ, which is the ratio of the discount rate to the intrinsic population growth rate, and (b) the preservation coefficient, Ω, which is the ratio of the preservation value (a measure of Society's value for the stock) to price, assuming that the population growth rate and intrinsic growth rate are fixed. It is shown that increasing Ω significantly impacts z*, particularly for moderate values of γ (2 γ 4). Finally, stochastic population models are used to analyze the risk of a fish stock collapse due to harvesting pressures. The bioeconomic models and simulations herein described improve the accuracy and reliability of maximum sustainable yield management.  相似文献   

10.
ABSTRACT: In May 1993, a single-family home and adjoining information center opened to the public at the Desert Botanical Garden in Phoenix, Arizona. Desert House is designed as an example of what can be achieved today using available technology to improve residential water and energy efficiency. The home is expected to reduce water and energy use by 40 percent compared with that for the typical three-bedroom, single-family residence in the Phoenix area. Water-conserving features include: landscape design employing low-water use plants, minimum turf area, mulch around plants to reduce evaporation, and drip irrigation system; spa cover for evaporation reduction; rainwater harvesting; low-flow shower heads, faucets, and toilets; and graywater reuse system. The home will be occupied by a family and monitored for water and energy use by computer. Visitors are able to access real time water and energy use data about the home, as well as tour the information center, technical exhibits, surrounding landscape, and the home when it is open (one afternoon a week).  相似文献   

11.
One potentially significant, yet hardly investigated, criterion for postoccupancy evaluation is the legibility of a setting—the degree to which a building or group of buildings facilitate the ability of users to find their way around. Legibility is one of the foundation concepts of environmental psychology, yet it has not often been considered enough as a guiding principle in design. The purpose of this paper is to analyse spatial orientation and wayfinding problems encountered by newcomers (freshman students) at the King Saud University (KSU) campus, Saudi Arabia, and to test/relate this to Lynch's elements of the image of cities. The analysis draws on previous research findings, theories, and more general observations, as well as observations made of wayfinding performance and map sketching by 30 high-school students likely to soon enroll at the university. Many specific problems with orientation and the architectural legibility of the buildings are identified and discussed. Emphasis is placed upon physical-setting variables that are likely to affect the ease with which spatial orientation and wayfinding are accomplished. These include the following facets of the KSU built environment: degree of differentiation; degree of visual access; and complexity of spatial layout.Legible buildings within which people can effectively maintain their orientation and find their way, according to this research, are in no way simplistic, dull, or boring; on the contrary, settings must possess distinctive landmarks and regions which, along with understandable path networks, allow users to know where they are and how to make their way to desired destinations. Coherent and legible environments are important in the lives of the people who use them. The movement of people through buildings and the factors that influence whether or not they are able to find their way need to continue to be of significance to both researchers and practitioners.  相似文献   

12.
13.
Abstract: The impacts of runoff events on external suspended solids loading to Schoharie Reservoir, New York, and patterns of light scattering and sediment deposition in this reservoir are assessed. The assessment is based on monitoring of suspended solids concentrations in the reservoir's primary tributary, detailed vertical profiles of optical backscattering (a surrogate measure of light scattering) in the reservoir water column, and analysis of sediment trap collections, over a seven-month interval of high runoff. These impacts are reported to be tightly temporally coupled and strongly positively related to the magnitude of runoff events. The primary tributary entered the reservoir as a plunging inflow during runoff events, causing conspicuous subsurface peaks in light scattering, with vertical patterns that varied strongly for different events. Deposition quantified by near-bottom trap deployments is reported to be more representative than results from metalimnetic deployments that were generally within, rather than below, the turbid layers. Direct inputs of sediment, transported by density currents, are found to drive deposition, rather than resuspension/redeposition. More than 50 percent of the reported deposition occurred in less than 15 percent of the study period, associated with the four largest runoff events.  相似文献   

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