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Elizabeth H. Rave Robert C. Fleischer Fern Duvall Jeffrey M. Black 《Conservation biology》1994,8(3):744-751
DNA fingerprinting was used to assess levels of genetic variation in 106 Hawaiian Geese, or Nene ( Branta sandvicensis ), from two captive colonies in Hawaii and Slimbridge, England. Mantel tests were used to determine differences in mean similarity coefficients obtained from DNA fingerprints between unrelated and related Nene within and between captive colonies and to determine whether pedigree-based estimates of relatedness correlated with DNA fingerprint-based estimates. Between colonies, mean similarity coefficients for unrelated and related Slimbridge Nene were higher than those for Hawaiian Nene. Within each colony, related Nene bad higher mean similarity coefficients than did unrelated Nene. A positive relationship was found between coancestry coefficients and similarity coefficients. A greater number of founders for the Hawaiian colony contributed to the lower mean similarity coefficients. As genetic variation decreases, difficulty in distinguishing relatedness among individuals using DNA fingerprinting may increase. Lower genetic variation also may increase tine error in estimating the relationship between coancestry and similarity coefficients. DNA fingerprinting of Nene identified unique alleles and can determine optimal pairings between individuals. The calibrated similarity coefficient distributions can help determine the relatedness of individuals in wild populations of Nene. 相似文献
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Recycling policy, insofar as it exists, tends to be heavily weighted towards price manipulation. However, it is by now fairly well established that the supply of secondary materials is in most cases quite unresponsive to price changes, so that price-based policies are very unlikely to be effective. This view is further borne out by an attempt to consider explicitly the sort of adjustment processes which must necessarily occur in the generally volatile markets for waste materials. It is suggested that price-oriented policies must first influence the expectations of potential suppliers before any response is forthcoming When this is considered along with the evidently small reaction to those expectations, an even more pessimistic conclusion about the suitability of standard measures to encourage recycling is reached. 相似文献
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Reintroduction of animals to the wild to establish free-ranging viable populations is a valuable conservation tool, but ecological skills alone are not enough to ensure a successful reintroduction; also needed to do the work are effectively designed and managed programs. This article suggests general guidelines for organizing and managing reintroduction programs, reviews some basic organizational issues, and considers ways to develop high-performance teams The need to integrate reintroduction programs into their larger interorganizational context is discussed. The reintroduction program's structure must be appropriate for its function and should be properly staffed, led, and buffered from its political environment It should process information well, learn rapidly from its own mistakes, and be creative A high-performance team devotes most of its energies to solving external rather than internal problems 相似文献
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Neville Millar G. Philip Robertson Peter R. Grace Ron J. Gehl John P. Hoben 《Mitigation and Adaptation Strategies for Global Change》2010,15(2):185-204
Nitrous oxide (N2O) is a major greenhouse gas (GHG) product of intensive agriculture. Fertilizer nitrogen (N) rate is the best single predictor
of N2O emissions in row-crop agriculture in the US Midwest. We use this relationship to propose a transparent, scientifically robust
protocol that can be utilized by developers of agricultural offset projects for generating fungible GHG emission reduction
credits for the emerging US carbon cap and trade market. By coupling predicted N2O flux with the recently developed maximum return to N (MRTN) approach for determining economically profitable N input rates
for optimized crop yield, we provide the basis for incentivizing N2O reductions without affecting yields. The protocol, if widely adopted, could reduce N2O from fertilized row-crop agriculture by more than 50%. Although other management and environmental factors can influence
N2O emissions, fertilizer N rate can be viewed as a single unambiguous proxy—a transparent, tangible, and readily manageable
commodity. Our protocol addresses baseline establishment, additionality, permanence, variability, and leakage, and provides
for producers and other stakeholders the economic and environmental incentives necessary for adoption of agricultural N2O reduction offset projects. 相似文献
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Istre GR McCoy M Stowe M Barnard JJ Moore BJ Anderson RJ 《Traffic injury prevention》2007,8(4):398-402
OBJECTIVE: To explore the epidemiology of pedestrian deaths in Dallas County, Texas, and to compare factors associated with pedestrian deaths on expressways versus those that occurred on other roadways. METHODS: We studied all pedestrian deaths among persons 15 years of age or older in Dallas County, Texas, from 1997 to 2004 by linking data from Medical Examiner's office, the Fatality Analysis Reporting System, and local police records. Univariate and multivariate analysis compared various factors associated with death on an expressway. RESULTS: Among 437 pedestrian deaths who were 15 years of age or older, 197 (45%) occurred on expressways; the proportion that occurred on expressways was highest among 15- to 29-year-olds (65%) and was lower with advancing age group (p < 0.01, chi square for trend). At least 36% of these expressway-related pedestrian deaths were known to have been "unintended pedestrians," who had exited a vehicle after being on the roadway, compared with 11% of pedestrian deaths on surface streets (OR 4.6, 95% CI, 2.7-8.1), and this was also highest among younger age groups. Pedestrian deaths on an expressway, compared with deaths on surface streets, remained strongly associated with having been an "unintended pedestrian" (OR 6.2, 95% CI, 3.1-14.0), after controlling for several other variables, including age, sex, race, nighttime of crash, and alcohol involvement. CONCLUSIONS: Expressways are the predominant site of fatal pedestrian crashes among young adults in this urban area. Since many of these deaths were "unintended pedestrians," procedures for management of occupants of disabled vehicles on expressways could have a large impact on pedestrian deaths in young adults. 相似文献