| 1. |
- Gromov, Sergey P, et al.
(författare)
-
Synthesis, Structure, Spectroscopic Studies, and Complexation of Novel Crown Ether Butadienyl Dyes
- 2002
-
Ingår i: Helvetica Chimica Acta. ; 85:1, s. 60-81
-
Tidskriftsartikel (refereegranskat)abstract
- Butadienyl dyes of the benzothiazole series with various fragments of benzocrown ethers 1a-c were synthesized for the first time. The structures and spectral properties of crown-containing butadienyl dyes and their complexes with alkali and alkaline-earth metal cations were studied by X-ray diffraction analysis and 1H-NMR, UV/VIS, and resonance Raman spectroscopy. To interpret the experimental results, quantum-chemical calculations were performed. In the case of Sr2+ and Ba2+ ions, the formation of strong sandwich complexes [M(1b)2]2+ of an unusual structure involving stacking interactions was established; the dye molecules are arranged one above another in the complex according to the head-to-head' pattern.
|
|
| 2. |
- Lettevall, Erland, et al.
(författare)
-
Social structure and residency in aggregations of male sperm whales
- 2002
-
Ingår i: Canadian Journal of Zoology-Revue Canadienne De Zoologie. - 0008-4301. ; 80:7, s. 1189-1196
-
Tidskriftsartikel (refereegranskat)abstract
- Sperm whales (Physeter macrocephalus) are sexually dimorphic in several respects, including size, latitudinal distribution, and social structure. Females are known to have complex social structures, including long-term bonds, but the social structures of sexually mature or maturing males have received much less attention. Using data from aggregations of males off Norway, Nova Scotia, New Zealand, and the Galapagos Islands, we examined aggregation size, residence times within aggregations, clustering at the surface, and long-term bonds. Results were generally consistent among study areas. The aggregations found in each area contained around 10-30 males at any time, and were usually a few tens of kilometres across. Mean residence times within aggregations ranged from a few days to a few weeks. Close clustering at the surface was rare, but present at each site. There was no evidence for preferred companionship between individuals at any temporal scale in any of the study areas. The rarity of clustering and the apparent lack of long-term relationships amongst male sperm whales contrast strongly with results of studies on females, suggesting that both close spatial proximity at the surface and permanent bonds between individuals may be a consequence of the need for care of the young.
|
|
