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311.
Humans are rapidly depleting critical ecosystems and the life support functions they provide, increasing the urgency of developing effective conservation tools. Using a case study of the conversion of mangrove ecosystems to shrimp aquaculture, this article describes an effort to develop a transdisciplinary, transinstitutional approach to conservation that simultaneously trains future generations of environmental problem solvers. We worked in close collaboration with academics, non-government organizations, local government and local communities to organize a workshop in Puerto Princesa, Palawan, Philippines. The primary objectives of the workshop were to: (1) train participants in the basic principles of ecological economics and its goals of sustainable scale, just distribution and efficient allocation; (2) learn from local community stakeholders and participating scientists about the problems surrounding conversion of mangrove ecosystems to shrimp aquaculture; (3) draw on the skills and knowledge of all participants to develop potential solutions to the problem; and (4) communicate results to those with the power and authority to act on them. We found that the economic and ecological benefits of intact mangroves outweigh the returns to aquaculture. Perversely, however, private property rights to mangrove ecosystems favor inefficient, unjust and unsustainable allocation of the resource—a tragedy of the non-commons. We presented the workshop results to the press and local government, which shut down the aquaculture ponds to conserve the threatened ecosystem. Effective communication to appropriate audiences was essential for transforming research into action. Our approach is promising and can be readily applied to conservation research and advocacy projects worldwide, but should be improved through adaptive management—practitioners must continually build on those elements that work and discard or improve those that fail.  相似文献   
312.
Although most researchers now espouse a person‐by‐situation interactionist approach, there remains much work to be carried out to fully understand how different features of the environment interact with personality to influence behavior. Thus, this study sought to examine the moderating effects of three group‐level constructs on the relationships between two personality traits (conscientiousness and extraversion) and individual performance and counterproductive behaviors. Specifically, using trait activation theory as an organizing framework, we considered the moderating effects of the following: (i) a previously unexamined construct called core group evaluations (CGEs); (ii) group conscientiousness composition; and (iii) group extraversion composition. Data were obtained from a sample of university football players (N = 225–252 from 40 groups). The results indicated that CGEs moderated the relationships between individual conscientiousness and both performance (subjective) and counterproductive behaviors. Group conscientiousness composition also moderated the relationships between individual conscientiousness and both performance (objective and subjective) and counterproductive behaviors. Lastly, group extraversion composition moderated the relationship between individual extraversion and counterproductive behaviors. These findings highlight the importance of considering a team's CGEs, as well as the personality composition of team members when investigating the effects of conscientiousness and extraversion on individual performance and counterproductive behaviors. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   
313.
This paper presents the application of three publicly available biota dose assessment models (the ERICA Tool, R&D128/SP1a and RESRAD-BIOTA) to an assessment of the Drigg coastal sand dunes. Using measured 90Sr, 99Tc, 137Cs, 238Pu, 239+240Pu and 241Am activity concentrations in sand dune soil, activity concentration and dose rate predictions are made for a range of organisms including amphibians, birds, invertebrates, mammals, reptiles, plants and fungi. Predicted biota activity concentrations are compared to measured data where available. The main source of variability in the model predictions is the transfer parameters used and it is concluded that developing the available transfer databases should be a focus of future research effort. The value of taking an informed user approach to investigate the way in which models may be expected to be applied in practice is highlighted and a strategy for the future development of intercomparison exercises is presented.  相似文献   
314.
Renewable electricity policies promote investment in renewable electricity generators and have become increasingly common around the world. Because of intermittency and the composition of other generators in the power system, the value of certain renewable – particularly wind and solar – varies across locations and technologies. This paper investigates the implications of this heterogeneity for the cost effectiveness of renewable electricity policies. A simple model of the power system shows that renewable electricity policies cause different investment mixes. Policies also differ according to their effect on electricity prices, and both factors cause the cost effectiveness to vary across policies. We use a detailed, long-run planning model that accounts for intermittency on an hourly basis to compare the cost effectiveness for a range of policies and alternative parameter assumptions. The differences in cost effectiveness are economically significant, where broader policies, such as an emissions price, outperform renewable electricity policies.  相似文献   
315.
Halogenated disinfection byproducts (DBPs) are an unintended consequence of drinking water disinfection, and can have significant toxicity. XAD resins are commonly used to extract and enrich trace levels of DBPs for comprehensive, nontarget identification of DBPs and also for in vitro toxicity studies. However, XAD resin recoveries for complete classes of halogenated DBPs have not been evaluated, particularly for low, environmentally relevant levels (ng/L to low µg/L). Thus, it is not known whether levels of DBPs or the toxicity of drinking water might be underestimated. In this study, DAX-8/XAD-2 layered resins were evaluated, considering both adsorption and elution from the resins, for extracting 66 DBPs from water. Results demonstrate that among the 7 classes of DBPs investigated, trihalomethanes (THMs), including iodo-THMs, were the most efficiently adsorbed, with recovery of most THMs ranging from 50%-96%, followed by halonitromethanes (40%-90%). The adsorption ability of XAD resins for haloacetonitriles, haloacetamides, and haloacetaldehydes was highly dependent on the individual species. The adsorption capacity of XAD resins for haloacetic acids was lower (5%-48%), even after adjusting to pH 1 before extraction. Recovery efficiency for most DBPs was comparable with their adsorption, as most were eluted effectively from XAD resins by ethyl acetate. DBP polarity and molecular weight were the two most important factors that determine their recovery. Recovery of trichloromethane, iodoacetic acid, chloro- and iodo-acetonitrile, and chloroacetamide were among the lowest, which could lead to underestimation of toxicity, particularly for iodoacetic acid and iodo-acetonitrile, which are highly toxic.  相似文献   
316.
A comparison of the concentration of the total suspended particulate (TSP) matter measured by the tapered element oscillating microbalance (TEOM) monitor and the isokinetic TSP samplers developed at the University of Illinois was carried out in several types of confinement livestock buildings. In a majority of the measurements done, the dust concentration measured by the TEOM monitor was lower than the University of Illinois at Urbana-Champaign (UIUC) isokinetic TSP sampler; the TEOM monitor tended to underestimate the total dust concentration by as much as 54%. The difference in measurements can be attributed to the sampling efficiency of the TEOM monitor sampling head and the loss of some semivolatile compounds and particle-bound water because of heating of the TEOM monitor sampling stream to 50 degrees C. Although several articles in the literature supported the latter argument, this study did not investigate the effect of heating the sampling stream or the effect of moisture on the relative difference in dust concentration measurements. The model that best describes the relationship between the two methods was site specific, that is, the linear regression model was applicable only to four of the sites monitored. The measured total dust concentration in livestock buildings range from approximately 300 to 4000 microg/m3; a higher correlation coefficient between TEOM-TSP and UIUC-TSP monitors was obtained in swine facilities than those obtained in a laying facility.  相似文献   
317.
318.
The tropical spirostreptid millipede Alloporus uncinatus has a polygynandrous mating pattern that is apparently shaped by sperm competition (Telford and Dangerfield 1990, 1993a). In the present study radioisotopic labelling of ejaculates was used to quantify the temporal effects of double mating sequences on sperm precedence patterns. Ejaculates of successive males mix completely within the sperm storage organs and are concentrated close to the site of fertilisation, the spermathecal-oviduct junction. When matings follow each other immediately (experiment 1), equal volumes of the ejaculates of each male are stored within the spermathecae, and both males have equal probability of paternity. Where matings are separated by a 24-h delay (experiment 2), the volumetric contribution of the first male is reduced by 54.8 % and last male precedence operates. Although the distal ends of the gonopods play a primary role in the redistribution of ejaculates (Barnett and Telford 1994), by using a single mating sequence we show that they are not responsible for the reduction in ejaculate volume. The most likely explanation is absorption and/or ejection of the first male's ejaculate by the female. Genital functional morphology is used to reconstruct the mechanism of ejaculate distribution.  相似文献   
319.
ABSTRACT: A two-year study was conducted to assess the effect of hog manure on the losses of nitrogen and phosphorus in runoff and drainage from grain-corn (Zea mays L.) plots, and the importance of spring versus annual loads. Treatments consisted of mineral N-P-K fertilizer applied at rates of 152 kg N ha-1, 35 kg P ha-1, and 86 kg K ha-1; and hog (Sus scrofa domestica L.) manure applied preplant or post-emergence (six-to-eight leaf stage), at 152 kg N ha-1, 39 kg P ha-1, and 112 kg K ha-1. The plots were rototilled (7 cm depth) in spring to incorporate fertilizer and preplant hog manure, and fall chisel-plowed (15 cm depth) to incorporate chopped corn residues. They were arranged in a completely randomized plot design. Flow volumes and nutrient levels in runoff and drainage waters were monitored year round but occurred mainly during the snowmelt (March 25-April 9), and post.snowmelt (April 10-May 13) periods. Of the total amount of water lost during snowmelt, 90 percent was in runoff, while 92 percent occurred as drainage in the post-snowmelt period. Sixty-five percent of the total annual volume of water lost was lost during these two periods as runoff and drainage. Treatments did not affect the annual snowmelt or post-snowmelt N and P loads. Total annual loads averaged 8.0 kg TKN ha-1, 1.8 kg NH4-N ha-1, 43 kg NO3-N ha-1, 0.4 kg TP ha-1, and 0.15 kg PO4-P ha-1. Spring (snowmelt and ost-snowmelt) runoff and drainage loads averaged 2.9 kg TKN ha-1, 1.2 kg NH4-N ha-1, 18 kg NO3-N ha-1, 0.25 kg TP ha-1, and 0.04 kg PO4-P ha-1, which were 40 percent to 70 percent of the yearly nutrient loads. Therefore, the hog manure management systems examined were of no greater threat to the environment than mineral fertilizers. However, spring N and P losses do represent an important part of the annual nutrient loss budget, even with conservation practices.  相似文献   
320.
Platinum coordination complexes in cancer chemotherapy   总被引:3,自引:0,他引:3  
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