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741.
A female-specific attractant for the codling moth,<Emphasis Type="Italic"> Cydia pomonella</Emphasis>, from apple fruit volatiles 总被引:5,自引:1,他引:4
Host plant-derived esters were investigated as potential female-specific attractants for the codling moth (CM), Cydia pomonella (L.), a key pest of apples worldwide. The behavioural effects of single and combined volatile compounds and of a natural odour blend were examined using olfactometry and wind-tunnel bioassays. The apple-derived volatile butyl hexanoate attracted mated females while it was behaviourally ineffective for males over a dosage range of more than three orders of magnitude in olfactometer assays. Female CM preferred this kairomone to the headspace volatiles from ripe apples. Both no-choice and choice trials in the wind-tunnel suggested that female moths might be effectively trapped by means of this compound. In contrast, headspace volatiles collected from ripe apple fruits as well as a blend containing the six dominant esters from ripe apples were behaviourally ineffective. A female-specific repellency was found for the component hexyl acetate in the olfactometer, but this ester had no significant effect in the wind-tunnel. Butyl hexanoate with its sex-specific attraction should be further evaluated for monitoring and controlling CM females in orchards. 相似文献
742.
McCubbin D Leonard KS Young AK Maher BA Bennett S 《Journal of environmental radioactivity》2004,77(2):111-131
An assessment has been made of the association of (239+240)Pu, 241Am and 210Po (in secular equilibrium with 210Pb) with iron minerals using a magnetic extraction technique. Grab samples of beach sand from the Cumbrian (UK) coastline were subjected to successive extractions with an approximately 0.1 T ferrite magnet and an approximately 0.3 T rare-earth magnet procedure to separate magnetic iron oxide minerals. Radionuclide concentrations in the magnetic extracts were enhanced (by approximately 4-6-fold) relative to the residue. Those in the approximately 0.1 T magnet extracts were broadly similar to those in the antiferromagnetic material extracted by the approximately 0.3 T magnet, despite the very large differences in magnetic property values between the two fractions (one to two orders of magnitude). The percentage of magnetic material in terms of mass was small and therefore, the majority of these radionuclides (on average 88%) were associated with the residue. Removal of stable Fe was incomplete. Given that the radionuclides may also bind to paramagnetic (nonmagnetic) Fe minerals, the data were extrapolated by normalising the results to quantitative Fe removal. This yielded average values of 37%, 45% and 46% for (239+240)Pu, 241Am and 210Po(210Pb), respectively, as upper limits for the fraction associated with magnetic + nonmagnetic Fe minerals. There are significant uncertainties inherent in quantifying data from this extraction technique. Nevertheless, it seems reasonable to conclude that radionuclide association with Fe minerals is unlikely to have a significant impact upon the physical dispersion of sediment contaminated by Sellafield discharges in the Irish Sea. However, it may be an important factor in governing Pu redox and redissolution behaviour. 相似文献
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744.
Kreczko A 《Disasters》2003,27(3):239-258
From 1997 to 2001, the international community put in place unique mechanisms to address the challenges to providing humanitarian assistance in Taliban-run Afghanistan. The Afghan Support Group (ASG), Principled Common Programming (PCP) and the Strategic Framework (SF) constituted a precedent-setting experiment that consumed thousands of hours in implementation in donor capitals and in the field. This article, written from the perspective of the leading donor of humanitarian assistance to Afghanistan, assesses the extent to which this Afghan experiment succeeded in increasing coherence on assistance policy issues, improving efficiency in assistance programmes and added synergy between assistance and peace efforts; identifies factors that limited further achievements; suggests how the mechanisms could have been improved; and analyses whether the overall effort politicised humanitarian assistance. The article concludes that the record of achievement was sufficiently promising that the ASG/PCP/SF experiment should be considered for application in other complex humanitarian emergencies. 相似文献
745.
Grassroots watershed associations have formed as an avenue to facilitate public involvement in protecting watersheds. Growth in the number of watershed associations has created a need to evaluate whether their existence enhances environmental protection by local communities. In this research, environmental protection was measured by the number of watershed protection activities conducted and amount of funding directed towards protecting surface waters by non-profit, volunteer organizations. Regression models were utilized to examine the influence of population demographic and watershed characteristics variables to explain the formation of watershed associations along with watershed protection activities and funding. Regression results showed that the presence of watershed associations had positive impacts on both the number of activities and financial resources acquired. The results confirm that watershed associations enhance the ability of communities to obtain funding and to implement watershed protection actions. Thus, watershed associations serve as an effective institution for promoting environmental protection. 相似文献
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747.
Alan E. Donnenfeld M.D. Steven C. Scott Marie Henselder-Kimmel Carlton D. Dampier 《黑龙江环境通报》1994,14(8):721-724
Congenital transient leukaemia (CTL) is a haematological disorder characterized by proliferation of myeloblasts within the bone marrow and peripheral blood of affected newborns. Infants with Down syndrome are most frequently affected and although the disorder can result in fetal death due to hydrops, it typically resolves spontaneously after birth. We present a case of prenatally diagnosed fetal hydrops accompanied by splenomegaly and an enlarged, echogenic liver in a fetus identified with CTL after birth. 相似文献
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