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101.
Defining and measuring sustainability of bioenergy systems are difficult because the systems are complex, the science is in early stages of development, and there is a need to generalize what are inherently context-specific enterprises. These challenges, and the fact that decisions are being made now, create a need for improved communications among scientists as well as between scientists and decision makers. In order for scientists to provide information that is useful to decision makers, they need to come to an agreement on how to measure and report potential risks and benefits of diverse energy alternatives in a way that allows decision makers to compare options. Scientists also need to develop approaches that contribute information about problems and opportunities relevant to policy and decision making. The need for clear communication is especially important at this time when there is a plethora of scientific papers and reports and it is difficult for the public or decision makers to assess the merits of each analysis. We propose three communication guidelines for scientists whose work can contribute to decision making: (1) relationships between the question and the analytical approach should be clearly defined and make common sense; (2) the information should be presented in a manner that non-scientists can understand; and (3) the implications of methods, assumptions, and limitations should be clear. The scientists’ job is to analyze information to build a better understanding of environmental, cultural, and socioeconomic aspects of the sustainability of energy alternatives. The scientific process requires transparency, debate, review, and collaboration across disciplines and time. This paper serves as an introduction to the papers in the special issue on “Sustainability of Bioenergy Systems: Cradle to Grave” because scientific communication is essential to developing more sustainable energy systems. Together these four papers provide a framework under which the effects of bioenergy can be assessed and compared to other energy alternatives to foster sustainability.  相似文献   
102.
Government priorities on provincial Nutrient Management Planning (NMP) programs include improving the program effectiveness for environmental quality protection, and promoting more widespread adoption. Understanding the effect of NMP on both crop yield and key water-quality parameters in agricultural watersheds requires a comprehensive evaluation that takes into consideration important NMP attributes and location-specific farming conditions. This study applied the Soil and Water Assessment Tool (SWAT) to investigate the effects of crop and rotation sequence, tillage type, and nutrient N application rate on crop yield and the associated groundwater ${\text{NO}_{3}}^{ - } {\text{-N }}$ leaching and sediment loss. The SWAT model was applied to the Thomas Brook Watershed, located in the most intensively managed agricultural region of Nova Scotia, Canada. Cropping systems evaluated included seven fertilizer application rates and two tillage systems (i.e., conventional tillage and no-till). The analysis reflected cropping systems commonly managed by farmers in the Annapolis Valley region, including grain corn-based and potato-based cropping systems, and a vegetable-horticulture system. ANOVA models were developed and used to assess the effects of crop management choices on crop yield and two water-quality parameters (i.e., ${\text{NO}_{3}}^{ - } {\text{-N }}$ leaching and sediment loading). Results suggest that existing recommended N-fertilizer rate can be reduced by 10–25 %, for grain crop production, to significantly lower ${\text{NO}_{3}}^{ - } {\text{-N }}$ leaching (P > 0.05) while optimizing the crop yield. The analysis identified the nutrient N rates in combination with specific crops and rotation systems that can be used to manage ${\text{NO}_{3}}^{ - } {\text{-N }}$ leaching while balancing impacts on crop yields within the watershed.  相似文献   
103.
Abstract

A local sustainable development initiative to establish a temporary pedestrian zone within a Canadian urban community served as a research study into the efficacy of social capital in the development of a network for community action. This community-based initiative used social capital to overcome campaign obstacles and the campaign itself generated new social capital within the neighbourhood through the creation of adaptive networks of participants. The campaign succeeded in creating a part-time pedestrian-only space that serves as an educational example of change for sustainable community development that is replicable in other communities, and provides an example of alternative occupation of community space. Contrary to other literature, little evidence of “core burnout” was found although the network does continue to expend a large amount of effort and time on fundraising. While social capital is a powerful tool for local grassroots action, the availability of a critical source of economic capital may prove vital to the long-term success and sustainability of the network.  相似文献   
104.
A commercially available thermal-infrared scanning system was used to survey populations of several wildlife species. The system's ability to detect species of different sizes in varying habitats relative to conventional survey methods, to differentiate between species in the same habitat, and the influence of environtmental factors on operational aspects of employing this technology in the field were evaluated. Total costs for the surveys were approximately $0.36/ha. There were marked discrepancies in the counts of untrained observers and those from trained analysis. Computer-assisted analysis of infrared imagery recorded 52% fewer deer than were estimated from drive counts, and densities of moose were five times those estimated from conventional aerial methods. By flying concentric circles and using telephoto, detailed counts of turkeys and deer were possible. With the aid of computer-assisted analysis, infrared thermography may become a useful wildlife population survey tool. More research is needed to verify the actual efficiency of detection by combining aerial scans with ground truthing for a variely of species and habitals.  相似文献   
105.
106.
107.
The female aggression hypothesis states that resident females may be able to prevent polygyny by behaving aggressively towards intruding females. A critical test of the hypothesis is to provide prospecting females with a choice between displaying mated males some of which have initial mates with artificially reduced levels of aggressiveness. Here we present a mate choice experiment on pied flycatchers Ficedula hypoleuca. The species is a cavity nester, and resident females were prevented from behaving aggressively by enclosing them within their own nestboxes: narrowing the entrance hole so that they could not escape but could still let their head out and have some contact with their mate. This treament had only a minor influence on male behaviour. We studied whether the experimental males were better able to attract a new female than a control group of mated males. Four predictions from the female aggression hypothesis were supported. (1) Mating success of control males was positively related to the distance between their primary and secondary territory. (2) For experimental males, mating success was unrelated to interterritorial distance. (3) Experimental males had higher mating success than control males when the interterritorial distance was short but (4) not when it was long. Experimental males had much lower mating success than unmated males, as would be expected if prospecting females are able to discover male mating status from cues other than visits by primary females to their mates' secondary nest sites. Received: 5 January 1998 / Accepted after revision: 30 December 1998  相似文献   
108.
ABSTRACT: Predicting stream eutrophication potential from non-point source nutrient loading across large temporal and spatial scales is a significant problem. In this paper we describe how two physiological indicators of P stress of stream bioflims, alkaline phosphatase activity (APA) and stored (surplus) P relate to two predictors of P loading: annual P loading predicted by the watershed model SIMPLE, and stream concentrations of soluble reactive P (SRP) in eight subbasins in the illinois River basin in Oklahoma. Data for APA, surplus P, nutrients and water chemistry were obtained at watershed outlets once during the cold season and twice during the warm season. There was a negative curvilinear relationship between APA and both predictors. Best fit was achieved by APA vs. annual predicted P loading. Both SRP and P. load are potentially useful to identify subbasins requiring no pollution abatement and to establish a regional target for P-load reduction. Surplus P is not as useful as APA in establishing these thresholds.  相似文献   
109.

Problem

Falls from heights in residential construction are common, especially among inexperienced workers.

Methods

We conducted a comprehensive needs assessment to determine gaps in the school-based apprentice carpenters' fall prevention training. A team of carpenter instructors and researchers revised the fall prevention training to fill these gaps. Apprentice evaluation and feedback guided ongoing curricular improvements.

Results

Most apprentice carpenters performed work tasks at heights prior to training and fall protection techniques were not commonly used at residential construction sites. Priorities of the revised school-based training included safe ladder habits, truss setting, scaffold use, guarding floor openings, and using personal fall arrest systems. New apprentices were targeted to ensure training prior to exposure at the workplace. We used adult learning principles to emphasize hands-on experiences. A framed portion of a residential construction site was fabricated to practice fall protection behaviors in a realistic setting. The revised curriculum has been delivered consistently and apprentice feedback has been very favorable.

Conclusions

Integration of needs assessment results was invaluable in revising the school-based carpenters apprentice fall prevention curriculum. Working closely with the instructors to tailor learning experiences has provided preliminary positive results.

Impact on Industry

The fall safety of the residential construction industry continues to lag behind commercial construction and industrial settings. The National Occupational Research Agenda includes a Strategic Goal to strengthen and extend the reach of quality training and education in the construction industry via mechanisms such as construction safety and health training needs assessments. This study demonstrates how a structured process can be used to identify and remedy gaps and improve training effectiveness. We encourage others to take steps to assess and increase the impact of training efforts directed at all residential construction professionals; including both union and non-union workers. The implications are even greater in the non-union sector where most U.S. residential work is done.  相似文献   
110.
Methods of quantifying the roles of atmospheric acid inputs and internal acid generation by carbonic, organic, and nitric acids are illustrated by reviewing data sets from several intensively studied sites in North America. Some of the sites (tropical, temperate deciduous, and temperate coniferous) received acid precipitation whereas others (northern and subalpine) did not. Natural leaching by carbonic acid dominated soil leaching in the tropical and temperate coniferous sites, nitric acid (caused by nitrification) dominated leaching In an N-fixing temperate deciduous site, and organic acids dominated surface soil leaching in the subalpine site and contributed to leaching of surface soils in several other sites. Only at the temperate deciduous sites did atmospheric acid input play a major role in soil leaching. In no case, however, are the annual net losses of cations regarded as alarming as compared to soil exchangeable cation capital.

These results were used to illustrate the methods of quantifying the effects of atmospheric inputs and internal processes on soil leaching rates, not to draw broad generalizations as to acid rain effects on soils. However, there are predictable patterns in natural soil leaching processes which relate to climate, soil properties, and vegetation that may help in predicting the relative importances of natural vs. atmospheric acid inputs to soil leaching.  相似文献   
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