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551.
Summary The sex pheromone of the grain aphid,Sitobion avenae (Fab.), is identified as (4aS,7S,7aR)-nepetalactone, for which specific olfactory cells are located in the secondary rhinaria of the male antenna. The related (1R,4aS,7S,7aR)-nepetalactol was not produced by females in significant amounts (ca 10,000-fold less than the nepetalactone), although cells in the male antenna were found that responded specifically to this compound. Behavioural activity in the linear track ol-factometer showed attraction of males to the nepetalactone, but not to the nepetalactol.  相似文献   
552.
In 1994, the U.S. Department of Energy (DOE) initiated a contract reform program intended to strengthen oversight capabilities and encourage the creation of contract and incentive structures, which would effectively facilitate the treatment of onsite contamination and waste. The remedia‐tion and disposal of these legacy wastes is the core of the Department's environmental manage‐ment mission (Government Accountability Office [GAO], 2003). Despite a concerted effort toward achieving the goals of the reform, progress has been slow. Many projects continue to necessitate cost and time extensions above those originally agreed upon. Although the Department insti‐tuted an accelerated cleanup program in 2002, promising to shave some $50 billion and 35 years from its earlier cost and schedule projections, there have been delays in critical project areas that call into question the attainability of the proposed reductions (GAO, 2005). Numerous explana‐tions have been offered as to why achieving these goals has proven so difficult, many of which have concluded that flawed contracting practices are to blame. This article concludes that the root of the problem is much deeper and that the organizational criticisms aimed at DOE are as much a legacy as the waste itself. Although the focus of this article is on large former nuclear weapons sites, these types of contracting and organizational issues are often found at other gov‐ernment and private complex hazardous waste sites. © 2006 Wiley Periodicals, Inc.  相似文献   
553.
Retrospective ecological risk assessment, restoration, natural resource damage assessment (NRDA) and managing ecosystems all require having a baseline. This policy and practice paper explores the factors that influence baseline selection, and it is suggested that ecological resources would best be served by: (1) integrating NRDA considerations into both future land-use planning and remediation/restoration; (2) selecting a baseline for NRDA that approximates the land-use conditions at the time of occupation (or a preferred ecosystem); and (3) integrating both the positive and negative aspects of industrial occupation into restoration decisions, baseline selection and NRDA. Under the Comprehensive Environmental Response and Compensation and Liability Act (CERCLA), natural resource damages are assessed for injuries incurred since 1980 due to releases, but the release itself may have occurred before 1980. The paper uses the Department of Energy as a case study to examine NRDA and the management of ecosystems. Releases occurred at many DOE sites from the 1950s to the 1980s during nuclear bomb production. It is suggested that the DOE has been responsible not only for injuries to natural resources that occurred as a result of releases, but for significant ecosystem recovery since DOE occupation, because some lands were previously farmed or industrialized. Natural resource injuries due to releases occurred simultaneously with ecosystem recovery that resulted from DOE occupation. While the 1980 date is codified in CERCLA law as the time after which damages can be assessed, baseline can be defined as the conditions the natural resources would have been in today, but for the release of the hazardous substance. It is also suggested that NRDA considerations should be incorporated into the remediation and restoration process at DOE sites, thereby negating the need for formal NRDA following restoration, and reducing the final NRDA costs.  相似文献   
554.
The Consortium for Risk Evaluation with Stakeholder Participation (CRESP) was asked by the United States Department of Energy (US DOE) to consider the root causes of remediation projects that fail to entirely achieve their goals and then to offer suggestions to assist the Department. To begin this project, CRESP held several meetings at which the group defined problematic outcomes, the early symptoms of problematic outcomes, and the root causes of failing to meet expectations. The five root causes are complex science, engineering, and technology; ambiguous economics; project management shortcomings; political processes and credibility; and history and organizational culture. This article, while focusing on the US DOE, provides a larger context for many remediation projects that have failed to entirely live up to their sponsors' expectations. © 2007 Wiley Periodicals, Inc.  相似文献   
555.
Trichechus manatus ) in Puerto Rico is mortality due to human activities. We assessed 90 cases of manatee strandings in Puerto Rico based on historical data and a coordinated carcass salvage effort from 1990 through 1995. We determined patterns of mortality, including type of event, condition of carcasses, spatial and temporal distribution, gender, size/age class, and the cause of death. The spatial distribution of stranding events was not uniform, with the north, northeast, and south coasts having the highest numbers. Six clusters representing the highest incidence included the areas of Fajardo and Ceiba, Bahía de Jobos, Toa Baja, Guayanilla, Cabo Rojo, and Rio Grande to Luquillo. The number of reported cases has increased at an average rate of 9.6%/yr since 1990. The seasonality of stranding events showed a bimodal pattern, from February through April and in August and September. Most identified causes of death were due to human interaction, especially captures and watercraft collisions. Natural causes usually involved dependent calves. From 1990 through 1995, most deaths were attributed to watercraft collisions. A reduction in anthropogenic mortality of this endangered species can be accomplished only through education and a proactive management and conservation plan that includes law enforcement, mortality assessment, scientific research, rescue and rehabilitation, and inter- and intraagency cooperation.  相似文献   
556.
Swine sewage could be source of nutrients and pollutants. This work estimates the environmental risk in nine samples from different farm treatment systems based on the evaluation of their effects in Daphnia magna acute test, and on the assessment of Cu, Zn and ammonia as main contributors. NH3 and Cu were responsible for LC50 results (1-5% of dilution). Organic compounds were quantified through several extraction methods (SPMDs, SPE and solvent extraction). A more exhaustive extraction was performed in an additional sample, which showed indole and phenol recoveries much higher than the previous ones. This method also includes PCBs (430 ppb) and fatty acids (approximately =150 ppm) quantification.  相似文献   
557.
ABSTRACT: Regulatory water quality management has placed fairly extensive information expectations on routine, fixed-station monitoring without a corresponding emphasis being placed on the need to design monitoring systems to meet these expectations. To correct the situation there is increasing interest in developing more quantitative monitoring system design procedures which incorporate the statistical nature of sampling. In examining the development of such quantitative criteria, this paper describes the roles of statistics in a systematic approach to monitoring - initial design and routine reporting of results - and reviews the use of statistics in each. The paper emphasizes the need to tie the two together, via statistical design criteria, in order for the identified information expectations to be met in a statistically sound manner. However, the use of statistics in water quality monitoring is noted as currently being as much an art as it is a science.  相似文献   
558.
ABSTRACT: Streambank protection projects are intended to prevent streambank erosion, thereby preventing streambank failure and maintaining a desirable channel alignment. Streambank erosion is a natural process of unaltered, dynamic river systems, and protection projects seek to impose stability on this natural system. The environmental impacts of such projects are primarily changes to terrestrial and aquatic habitats and to aesthetics. Adverse environmental impacts have been minimized and enhancement of existing habitat and aesthetics have been achieved through the development of new, innovative designs or modifications to existing designs and through use of construction and maintenance practices that promote habitat and aesthetics. Designs based on channel flow characteristics, e.g., revetments using a variety of structural materials, can result in preservation of wildlife habitat by reducing the use of structural protection by matching the erosion potential of flow at the bank with the protection capability of the materials used. Designs based on streambed stabilization prevent bank failure caused by bank undermining, result in preservation or establishment of streamside vegetation, and enhance aesthetics. Protection schemes that manage and preserve floodplains, berms, and riparian areas preserve the natural condition of the floodplain area. Designs based on deflection of erosive flows, e.g., dikes, minimize disturbance to the bank vegetation and create low-velocity aquatic habitats. Use of vegetation for bank protection is most effective when used in combination with structural components. Construction and maintenance practices can be scheduled and modified to minimize impacts to floodplain areas and to enhance wildlife habitat while preserving the integrity of the protection structure.  相似文献   
559.
Summary Atlases of cancer mortality have recently appeared in many nations. This paper cautions environmental professionals against using them to draw cause-and-effect conclusions because of limitations of the map as a conveyor of information, and limitations of the data used in cancer atlases. Appropriate uses include, finding clues for detailed epidemiological and environmental research, places with poor data, regions requiring special equipment and personnel, and as tools for persuading the public to be less fatalistic about cancer and more supportive of public health protection and education programs.Dr Michael Greenberg is both Professor of the School of Urban and Regional Policy, and Acting Director of the Graduate Program in Public Health, at the University of Medicine and Dentistry and Rutgers University.  相似文献   
560.
ABSTRACT: Cumulative density functions (c.d.f.'s) for water quality random variables may be estimated using data from a routine grab sampling program. The c.d.f. may then be used to estimate the probability that a single grab sample will violate a given stream standard and to determine the anticipated number of violations in a given number of samples. Confidence limits about a particular point on the c.d.f. may be used to reflect the accuracy with which the sample estimate represents the true c.d.f. Methods are presented here for calculating such confidence limits using both a normal model and a nonparametric model. Examples are presented to illustrate the usefulness of an estimated c.d.f. and associated confidence limits in assessing whether an observed number of standard violations is the result of natural variability or represents real degradation in water quality.  相似文献   
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