| 11. |
- Parasnis, Dattatray S.
(författare)
-
PhD theses
- 1988
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 333:6171, s. 294-
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
|
|
| 12. |
|
|
| 13. |
- Ross, Russell G., et al.
(författare)
-
Unusual PT dependence of thermal conductivity for a clathrate hydrate
- 1981
-
Ingår i: Nature. - : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 290:5804, s. 322-323
-
Tidskriftsartikel (refereegranskat)abstract
- Molecular clathrate solids1 are crystals with peculiar and interesting properties. Their characteristic feature2 is that one chemical species, the ‘host’, forms a strongly bonded structure, which encages individual molecules of a second ‘guest’ species. There is virtually no chemical bonding between host and guest molecules. The guests are, nevertheless, firmly constrained by high energy barriers. X-ray and neutron diffraction experiments have shown that clathrates have a periodic structure typical of crystalline solids. A clathrate hydrate2 is a host substance consisting of H2O molecules which form an ice-like, hydrogen-bonded structure. Huge geological deposits of clathrate hydrates containing natural gas are known to exist2,3—these deposits may be exploitable, and in searching for clathrate hydrates knowledge of the thermal conductivity, λ, will be important. We present here a preliminary account of the first measurements of λ versus pressure (P) and temperature (T) for a clathrate hydrate. We studied a clathrate hydrate encaging molecules of tetrahydrofuran. Thermal conductivity was measured using the transient hot-wire method4. The accuracy of the measurements was 3% and the precision 1%. The temperature dependence was found to be unusual in that λ(T) has a positive slope (Fig. 1), a feature never before observed with crystalline organic materials. Furthermore, when λ was measured versus P, it was found unexpectedly that λ (P) was constant—behaviour never before reported for a non-metallic material.
|
|
| 14. |
|
|
| 15. |
|
|
| 16. |
- von Schantz, Torbjörn, et al.
(författare)
-
Female choice - Reply
- 1989
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 339:6224, s. 432-433
-
Tidskriftsartikel (refereegranskat)
|
|
| 17. |
- von Schantz, Torbjörn, et al.
(författare)
-
Female choice selects for a viability-based male trait in pheasants
- 1989
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 337, s. 166-169
-
Tidskriftsartikel (refereegranskat)abstract
- Recent theory on sexual selection1–4 suggests that females in species without paternal care choose mates by their secondary sexual characters because these indicate genotypic quality which will be transmitted to the offspring. These ideas are not yet empiri-cally supported as data quantifying the relationship between female mate choice and female reproductive success are lacking. Only in one case, in Colias butterflies, has it been demonstrated unequivo-cally that females choose 'good genotypes' as mates5 and there is only one study, on Drosophila, demonstrating that mate choice increases one component of offspring fitness6. Spur length of male pheasants (Phasianus colchicus) correlates with various fitness-related properties7. We here present the first experimental field data showing that female pheasants select mates on the basis of male spur length and that female mate choice correlates with female reproductive success.
|
|
| 18. |
- Zensus, J. A., et al.
(författare)
-
The inner radio jet of 3C273
- 1988
-
Ingår i: Nature. - London : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 334:6181, s. 410-412
-
Tidskriftsartikel (refereegranskat)abstract
- Radio maps of 3C273 obtained with very long baseline interferometry (VLBI) have been limited by low dynamic range and poor north-south resolution resulting from the low declination (2°) of this quasar1. Dramatic improvement can now be achieved using larger arrays and antennas in the Southern Hemisphere2,3. A new VLBI map, made at 5 GHz with angular resolution and dynamic range unsurpassed at this frequency for this source, shows a narrow jet extending to a projected distance lproj∼125 h-;1 parsecs from the core. Superluminal motion exists out to at least lproj≈46h-1 parsecs. Successive superluminal components emerge from the core and appear to move on a fixed curved path with similar speeds of about 1 milliarcseconds per year. © 1988 Nature Publishing Group.
|
|
| 19. |
- Zoback, Mary Lou, et al.
(författare)
-
Global patterns of tectonic stress
- 1989
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 341:6240, s. 291-298
-
Forskningsöversikt (refereegranskat)abstract
- Regional patterns of present-day tectonic stress can be used to evaluate the forces acting on the lithosphere and to investigate intraplate seismicity. Most intraplate regions are characterized by a compressional stress regime; extension is limited almost entirely to thermally uplifted regions. In several plates the maximum horizontal stress is subparallel to the direction of absolute plate motion, suggesting that the forces driving the plates also dominate the stress distribution in the plate interior.
|
|
| 20. |
|
|
