| 1. |
- Matveenko, L. I., et al.
(författare)
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The structure of the quasar 3C-345
- 1992
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Ingår i: Soviet Astronomy Letters. - Moscow : Rossijskaja akademija nauk / Russian Academy of Sciences. - 0320-0108. ; 18:6, s. 379-391
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Tidskriftsartikel (refereegranskat)abstract
- We study the fine structure of the quasar 3C 345 at a wavelength of 49 cm. The apparent size of the core and low-frequency variability are due to the opacity of the surrounding ionized medium and the electron density distribution. We find the distance dependence of the size and brightness temperature of the components. Relativistic plasma is being ejected into a cone, with vertex angle approximately 40-degrees in position -110-degrees. The jet consists of narrow twisted filaments.
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| 2. |
- Szöcs, G., et al.
(författare)
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Species discrimination in five species of winter-flying geometrids (Lepidoptera) based on chirality of semiochemicals and flight season
- 1993
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Ingår i: Journal of Chemical Ecology. - 0098-0331. ; 19:11, s. 2721-2735
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Tidskriftsartikel (refereegranskat)abstract
- Enantiomer separation of (6 Z,9 Z)-cis-3,4-epoxynonadecadiene and (3 Z,9 Z)-cis-6,7-epoxynonadecadiene could be achieved using chiral high-resolution gas chromatography and a cyclodextrin-bond column. (3 Z,9 Z)-(6 R,7 S)-Epoxynonadecadiene was identified from ovipositor extracts of Colotois pen-Naria, while in Erannis defoliaria the 6 S,7 R-enantiomer was found. In field trapping tests pure synthetic enantiomers caught only conspecific males of these species. (3 Z,6 Z,9 Z)-Nonadecatriene was found in both species, while the presence of (3 Z,6 Z,9 Z)-heneicosatriene was indicated in C. Pennaria only. A 10:10:3 blend of (3 Z,9 Z)-(6 R,7 S)-epoxynonadecadiene, (3 Z,6 Z,9 Z)-heneicosatriene, and (3 Z,6 Z,9 Z)-nonadecatriene was found to be optimal for catching C. Pennaria, while E. Defoliaria males were optimally caught by a 1:1 mixture of (3 Z,9 Z)-(6 S,7 R)-epoxynonadecadiene and (3 Z,6 Z,9 Z)-nona-decatriene. (6 Z,9 Z)-(3 S,4 R)-Epoxynonadecadiene was identified from ovipositor extracts of Agriopis (Erannis) aurantiaria. In field tests the pure enantiomer proved to be a highly specific sex attractant for both the late autumn/early winter flying A. Aurantiaria and the late winter/early spring flying A. Leucophearia. Males of Agriopis marginaria, which fly in late winter/early spring, were attracted to (3 Z,9 Z)-(6 S,7 R)-epoxynonadecadiene. The addition of (3 Z,6 Z,9 Z)-nonadecatriene to the S,R-enantiomer increased captures. Optimal catches were recorded with a 10:3 epoxide-hydrocarbon blend. Enantiomer specificity in all species was confirmed in EAG measurements.
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| 3. |
- Tóth, Miklos, et al.
(författare)
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Attraction of male turnip moths Agrotis segetum (Lepidoptera : Noctuidae) to sex pheromone components and their mixtures at 11 sites in Europe, Asia, and Africa
- 1992
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Ingår i: Journal of Chemical Ecology. - 0098-0331. ; 18:8, s. 1337-1347
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Tidskriftsartikel (refereegranskat)abstract
- Selected combinations of (Z)-5-decenyl, (Z)-7-dodecenyl, and (Z)-9-tetradecenyl acetates, the pheromone components of the turnip moth AgrotisSegetum were tested for field attractancy at six, two, and three sites in Europe, Asia, and Africa, respectively. At all of the sites in Eurasia and in northern Africa the ternary mixture of the acetates captured most males, while at the sites south of the Sahara in Africa, (Z)-5-decenyl acetate alone was responsible for attraction. Differences in male attraction among the populations studied confirm the existence of significant population variation in the pheromone of A. segetum. Interpretation of the present results together with earlier studies suggests that this variation is more or less continuous in Eurasia and north Africa, while a clearly distinct pheromone type is present in the areas south of the Sahara desert.
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| 4. |
- Tóth, Miklos, et al.
(författare)
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Pheromonal Production of and Response to Optically Active Epoxydienes in Some Ceometrid Moths (Lepidoptera: Geometridae)
- 1994
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Ingår i: Zeitschrift fur Naturforschung - Section C Journal of Biosciences. - : Walter de Gruyter GmbH. - 0939-5075. ; 49:7-8, s. 516-521
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Tidskriftsartikel (refereegranskat)abstract
- In, pheromone extracts of calling female Chiasma clathrata, L. (Lepidoptera: Geometridae), a defoliator pest of alfalfa, (Z,Z,Z)-3,6,9–heptadecatriene and (Z,Z)-6,9–cis-3,4–epoxyhepta-decadiene was identified. Chiral gas chromatography using a modified cyclodextrin and synthetic reference samples proved the natural epoxide to show (3 R.4 S)-configuration. In field trapping tests, only the pure (3/R,4S)-enantiomer of the epoxide attracted males. The addition of the triene component was synergistic. Males of the sympatric species Tephrina arenaceciria Hbn. (Lepidoptera: Geometridae) were caught only in traps with baits containing the (3S,4R)-enantiomer [together with a previously described minor component, (Z,Z)-3,9–cis-6,7–epoxyheptadecadiene], In trapping tests conducted iNADifferent biotope Abraxas grossu-lariata, L. (Lepidoptera: Geometridae) males were attracted by the (3S,4R)-enantiomer, whereas the (3/L4S)-enantiomer attracted a close relative. Abraxas sylvata Scop. (Lepidoptera: Geometridae). The present results suggest that one of the key mechanisms responsible for pheromone specificity among both the two alfalfa geometrids and the two Abraxas species in their respective biotops, may be the use of different enantiomers of the same polyene-derived epoxide as a sex pheromone component. It is probable that this discrimination mechanism is widespread among moth species utilizing epoxide pheromone components.
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