The burden of competitive grants     

Leopold AC 《Science (New York, N.Y.)》1979,203(4381):607

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Ecdysial failures in the cotton boll weevil: Synergism of diflubenzuron with juvenile hormone     

R.A. Leopold  E.P. Marks  J.K. Eaton  J. Knoper 《Pesticide biochemistry and physiology》1985,24(2):267-283

The frequency and etiology of ecdysial failures occurring during the pupal-adult transformation of the cotton boll weevil, Anthonomus grandis, was studied after treatment with juvenile hormone (JH) and/or diflubenzuron (DFB). Failure at emergence was the result of inability of the adult insects to escape from their pupal exuviae. Teratogenic effects in the form of pupal-adult intermediates or adults with pupal characters were not obtained with JH or DFB treatment after the larval-pupal ecdysis. Combining JH with the DFB treatment yielded a synergistic response that increased the frequency of ecdysial failures about sevenfold when applied in the later pupal stages. The fine structure of the abdominal cuticle of adults experiencing ecdysial failure after treatment with JH as white-eyed pupae exhibited granular deposits within the lamellar region and interference with deposition of the nonlamellate endocuticle. DFB treatment of the earlier pupal stages interfered with deposition of the lamellate cuticle by eliminating or reducing the lamellar structure. It was concluded that the primary interaction of JH with DFB was that of extending or reinitiating DFB sensitivity in the later pharate adult. A secondary interaction may involve inhibition of cuticle hardening as both JH and DFB appear to inhibit the tanning process of adults treated as white-eyed pupae.  相似文献   

The relationship between agricultural environments and olfactory dysfunction     

Snyder MC  Leopold DA  Chiu BC  Von Essen SG  Liebentritt N 《Journal of agricultural safety and health》2003,9(3):211-219

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Aroma compound analysis of Eruca sativa (Brassicaceae) SPME headspace leaf samples using GC,GC-MS,and olfactometry     

Jirovetz L  Smith D  Buchbauer G 《Journal of agricultural and food chemistry》2002,50(16):4643-4646

The aroma compounds of rocket salad (Eruca sativa) SPME headspace samples of fresh leaves were analyzed using GC, GC-MS, and olfactometry. More than 50 constituents of the Eruca headspace could be identified to be essential volatiles, responsible for the characteristic intense green; herbal; nutty and almond-like; Brassicaceae-like (direction of cabbage, broccoli, and mustard); and horseradish-like aroma of these salad leaves. As aroma impact compounds, especially isothiocyanates, and derivatives of butane, hexane, octane, and nonane were identified. 4-Methylthiobutyl isothiocyanate (14.2%), cis-3-hexen-1-ol (11.0%), cis-3-hexenyl butanoate (10.8%), 5-methylthiopentyl isothiocyanate (9.3%), cis-3-hexenyl 2-methylbutanoate (5.4%), and 5-methylthiopentanenitrile (5.0%) were found in concentrations higher than 5.0% (calculated as % peak area of GC analysis using a nonpolar column).  相似文献   

Richard Helmer and Ivanildo Hespanhol (eds.), Water Pollution Control. A Guide to the Use of Water Quality Management Principles     

Füreder  Leopold 《Water, air, and soil pollution》1999,110(3-4):435-437

Water, Air, &; Soil Pollution -  相似文献   

Die waldsch?tzung bei der Enteignung     

Leopold Husnagl 《Forstwissenschaftliches Centralblatt》1939,61(17):532-544

Ohne Zusammenfassung  相似文献   

Das Alter des Holzes     

Ing. Dr. Leopold Hufnagl 《European Journal of Forest Research》1929,51(1):20-22

Ohne Zusammenfassung  相似文献   

Abrupt uplift within the past 1700 years at southern puget sound, washington     

Bucknam RC  Hemphill-Haley E  Leopold EB 《Science (New York, N.Y.)》1992,258(5088):1611-1614

Shorelines rose as much as 7 meters along southern Puget Sound and Hood Canal between 500 and 1700 years ago. Evidence for this uplift consists of elevated wave-cut shore platforms near Seattle and emerged, peat-covered tidal flats as much as 60 kilometers to the southwest. The uplift was too rapid for waves to leave intermediate shorelines on even the best preserved platform. The tidal flats also emerged abruptly; they changed into freshwater swamps and meadows without first becoming tidal marshes. Where uplift was greatest, it adjoined an inferred fault that crosses Puget Sound at Seattle and it probably accompanied reverse slip on that fault 1000 to 1100 years ago. The uplift and probable fault slip show that the crust of the North America plate contains potential sources of damaging earthquakes in the Puget Sound region.  相似文献   

Mass mortality of common eiders (Somateria mollissima) in the Dutch Wadden Sea, winter 1999/2000: starvation in a commercially exploited wetland of international importance     

C.J Camphuysen  C.M BerrevoetsH.J.W.M Cremers  A DekingaR Dekker  B.J EnsT.M van der Have  R.K.H Kats  T KuikenM.F Leopold  J van der MeerT Piersma 《Biological conservation》2002,106(3):303-317

Mass mortality of common eiders (Somateria mollissima) was observed in winter 1999/2000 in the Dutch Wadden Sea. Approximately 21,000 common eiders died. Dissected birds were severely emaciated and 94% were infected with the acanthocephalan parasite Profilicollis botulus. Green shore crabs (Carcinus maenas), intermediate hosts of the parasite, were slightly more ‘available’ than in other years, but parasite infections in the eiders were close to normal. Few eiders were oiled (5%), there were no toxicological, bacteriological, or virological explanations for the observed mortality.In the Wadden Sea, a wetland of international importance, mussel (Mytilus edulis) cultures occur in sublittoral areas, while mechanical cockle (Cerastoderma edule) fisheries are licensed annually after evaluation of available resources. The wintering eiders in 1999/2000 required c. 3.1 million kg ash-free dry mass, while information on mussel and cockle stocks (irrespective of accessibility and profitability) suggested a resource 4.7× the requirement of common eiders only. Food shortage is suggested to have caused the observed mortality, involving both principal (mussels and cockles) and secondary (Spisula) prey.Winter census reports showed shifts in wintering distribution of common eiders in the 1990s, indicating the utilisation of Spisula in the North Sea in poor food years in the Wadden Sea. Following particularly intense fisheries in summer 1999, attempts to feed on Spisula in winter 1999/2000 failed. It is hypothesised that overfishing of mussels and cockles in the Wadden Sea in the early 1990s resulted in structurally reduced food resources, contractions of the foraging area of common eiders, and increased use of secondary prey in the North Sea.  相似文献   

Mössbauer studies of the speciation of tributyltin compounds in seawater and sediment samples     

George Eng  Orin Bathersfield  Leopold May 《Water, air, and soil pollution》1986,27(1-2):191-197

The antifoulant agents, bis-(tributyltin) oxide (TBTO), tributyltin acetate (TBTOAc) and tributyltin chloride (TBTCI) were mixed with various media. These media included distilled water, seawater, aerobic and anaerobic sediments. The Mossbauer spectra of the chloroform extracts of the distilled water and seawater mixed with these compounds were examined. The componds were mixed with aerobic and anaerobic sediments, and the Mossbauer spectra of the sediments were also examined. TBTO was converted to the hydroxide compound in all media except in anaerobic sediment where it was converted to an unidentified compound. TBTOAc and TBTCI were not changed by mixing with distilled water and aerobic sediment but were converted to the hydroxide compound in seawater and in anaerobic sediment.  相似文献