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131.
KEVIN T. DUFFY-DENO 《Growth and change》1997,28(3):263-288
A common argument advanced in the non-metropolitan counties of the US West is that the Endangered Species Act (ESA) can have, and has had, a devastating effect on local economies. However, to date, there has not been a systematic empirical analysis of the ESA's effect on local economies. This paper reports on such an analysis. Based on a sample of all 333 non-metropolitan counties in the eleven-state West, the statistical effect of the listing of threatened and endangered species on county employment growth between 1980 and 1990 is estimated. The paper's primary finding is that the hypothesis that endangered species listing has had a negative effect on the non-metropolitan county economies of the US West is not supported by the data. 相似文献
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133.
Discovery and characterization of sulfoxaflor, a novel insecticide targeting sap-feeding pests 总被引:5,自引:0,他引:5
Zhu Y Loso MR Watson GB Sparks TC Rogers RB Huang JX Gerwick BC Babcock JM Kelley D Hegde VB Nugent BM Renga JM Denholm I Gorman K DeBoer GJ Hasler J Meade T Thomas JD 《Journal of agricultural and food chemistry》2011,59(7):2950-2957
The discovery of sulfoxaflor [N-[methyloxido[1-[6-(trifluoromethyl)-3-pyridinyl]ethyl]-λ(4)-sulfanylidene] cyanamide] resulted from an investigation of the sulfoximine functional group as a novel bioactive scaffold for insecticidal activity and a subsequent extensive structure-activity relationship study. Sulfoxaflor, the first product from this new class (the sulfoximines) of insect control agents, exhibits broad-spectrum efficacy against many sap-feeding insect pests, including aphids, whiteflies, hoppers, and Lygus, with levels of activity that are comparable to those of other classes of insecticides targeting sap-feeding insects, including the neonicotinoids. However, no cross-resistance has been observed between sulfoxaflor and neonicotinoids such as imidacloprid, apparently the result of differences in susceptibility to oxidative metabolism. Available data are consistent with sulfoxaflor acting via the insect nicotinic receptor in a complex manner. These observations reflect the unique structure of the sulfoximines compared with neonicotinoids. 相似文献
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136.
A microencapsulated formulation that gives a burst release of piperonyl butoxide (PBO) several hours before a burst release of a conventional pyrethroid can effectively overcome metabolic resistance in Bemisia tabaci Gennadius, Helicoverpa armigera (Hübner), Aphis gossypii Glover and Myzus persicae Sulzer. This increase in efficacy against resistant pests was reflected in a field trial against B. tabaci on cotton, eliminating the need for two treatments. The ratio between the active insecticide and the synergist was found to be crucial in reducing resistance factors. 相似文献
137.
Benjamin J. Rook Michael J. Hansen Cory A. Goldsworthy Bradley A. Ray Owen T. Gorman Daniel L. Yule Charles R. Bronte 《Fisheries Management and Ecology》2021,28(3):195-210
Historically, cisco Coregonus artedi Lesueur was the predominant prey fish and target of commercial fisheries throughout Lake Superior, but most spawning stocks collapsed by the mid-1900s. Stocks partially recovered by the early 1990s, but contemporary abundance is considered to be below historical levels and driven by intermittent recruitment. Stochastic, age-structured simulation models were used to determine whether historical (pre-1955) cisco yield in Lake Superior was consistent with contemporary (1992–2015) abundance, life-history characteristics and recruitment dynamics. When compared to contemporary stocks, the findings suggest historical stocks had: (1) similar recruits per spawner at low spawning stock sizes; (2) lower rates of compensatory density dependence; (3) similar or lower recruitment variation depending on the area and (4) higher median adult and age-1 density. These findings are consistent with the hypothesis that eutrophication during the historical period supported greater recruitment and adult abundance and that re-oligotrophication during the contemporary period may be limiting full recovery. 相似文献
138.
ABSTRACT Proponents of petroleum industry subsidies often assert that such policies will have positive economic implications for rural communities. This paper examines the economic impacts of such a policy in Utah. Specifically, this paper quantifies the direct and indirect economic and fiscal impacts of a tax credit granted for oil and gas well workovers in Utah's Uintah Basin. The analysis is made possible by an input-output model constructed specifically for Utah's oil producing economy. The tax credit policy was found to generate a net fiscal loss for the state. However, it does generate employment in the Uintah Basin. The total per job cost to the state of generating an average of one job per year for 5 years through the tax credit policy is $24,056 (1991 dollars). However, if the public expenditure impacts are taken into account, then the cost per job could be as high as $48,423 (1991 dollars). Whether there are other ways to generate the same employment gains at a lower cost was lost in the political debate surrounding this petroleum industry tax credit. 相似文献
139.
The clinicopathological features of 90 cases of canine multicentric lymphoma are described. The majority of cases occurred in middle-aged dogs (five to eight years of age) with a mean age at presentation of 6–7 years. A marked sex predisposition was noted with male dogs out numbering females by 2:1. No significant breed predispositions were found. The most common presentation was a generalised lymphadenopathy but in approximately one-third of the cases this was accompanied by other signs including polyuria and polydipsia, facial oedema and upper respiratory tract obstruction. Approximately two-thirds of all the cases showed non-specific haematological abnormalities including thrombocytopenia, anaemia and white blood cell anomalies. All the cases were clinically staged according to the anatomical extent of the disease. The majority of the dogs were classified as stage 3 or above, denoting that the disease is invariably widespread or systemic upon initial presentation. 相似文献
140.
Cross-neutralization of genetic reassortants of bluetongue virus serotypes 20 and 21 总被引:4,自引:0,他引:4
Genetic reassortment studies of bluetongue virus (BTV) Types 20 and 21 have revealed a reassortant genotype that was not neutralized serotype-specifically. In reciprocal neutralization tests, BTV 20 and 21 were neutralized specifically by homologous antiserum. Similarly, reassortants that possessed both outer capsid proteins (i.e., VP2 and VP5) from the same parent virus reacted with that antiserum specifically. However, two reassortants, 16(9) and 19(1), with VP2 of BTV 20 and VP5 of BTV 21 had intermediate neutralization characteristics. These reassortants were neutralized to high titres by antiserum to BTV 20 and to lower, but significant titres by antiserum to BTV 21. In addition, antiserum to BTV 20 induced 10-16-fold higher titres in plaque reduction neutralization (PRN) tests with these two reassortants compared with BTV 20 itself. Evidence of the serological cross-reactivity of Reassortants 16(9) and 19(1) was also found with respect to reductions in plaque sizes observed in the PRN tests. The average plaque sizes of these reassortants were reduced to differing extents by antiserum to BTV 20 and 21, while those formed by the parent viruses were reduced in size by homologous antiserum only. Immunoblotting analysis of the structural proteins of BTV 20 and 21 demonstrated that VP2 alone was antigenically distinct, therefore confirming its role in determining serotype specificity in virus-neutralization tests. Electrophoretic analysis revealed considerable migrational differences between VP2 and VP5 of the parent viruses, suggesting that there was some divergence in their molecular weights, intrinsic charges or structural compositions. Taken together, the data suggest that the intermediate neutralization characteristics of the reassortants that contain VP2 and VP5 from different parent viruses are due to conformational alterations in their outer capsid structure which allow antibody recognition of common neutralizing epitopes that are not exposed on BTV 20 or BTV 21. 相似文献