Rattlesnake Expedition
260
(III) cation exhibit the same electron configuration, hence the very similar
physical and chemical properties. The gradual filling with electrons of the 14
positions in the inner 4f shell leads to a gradual change in properties with
increasing atomic number. At exactly half fIlled 4f shell, as for gadolinium
(Gd), energetic advantage may yield anomalous properties. Concentrations
in seawater ranging from about 10 pmoll- 1 (57La) down to about 0.1 pmoll-1
(71Lu). When normalized to crustal abundance the seawater values increase
gradually with increasing atomic number. The isotopic signature of
neodymium (Nd) varies between ocean basins. Exist in trivalent (III) cationic oxidation state in nature, except for cerium (Ce) and europium (Eu), which
may also occur in tetravalent (IV) and divalent (II) oxidation states.
Rattlesnake Expedition (1846-1850) this ship was sent to the south -western Pacific
under Captain Owen Stanley to continue surveying work particularly for a
safe ships route through the Torres Strait and the Great Barrier Reef. Extensive
surface and subsurface temperature measurements were carried out by Joseph
Dayman using self-registering maximum and minimum thermometers.
Marine collections were made by John MacGillivray (naturalist) and Thomas
Henry Huxley (assistant surgeon and naturalist). The voyage had profound
influence on T.H. Huxley [comparable to that of the Beagle on C.R. Darwin
(~Beagle Expedition)]. It started Huxley's life-long interest in comparative morphology. His diary of the cruise was edited in 1935 by his grandson.
Rayleigh number a nondimensional number, Ra, named after the British physicist Lord Rayleigh (1842-1919), that gives the ratio between the buoyancy
force and the combined opposing effects of viscosity and diffusive transport
of buoyancy. If the Rayleigh number exceeds a certain critical value, the fluid
becomes unstable and convection sets in. Usually the buoyancy will result
from heating, and the thermal expansion coefficient is incorporated in Ra,
but when buoyancy is connected with salinity differences (as in estuaries), the
volume contraction coefficient for salinity will be incorporated in a Rayleigh
number for salinity.
ray path is a line following the propagation direction of the waves, and is everywhere perpendicular to the wave crests. Between two adjacent ray paths the
available wave energy is conserved. So, if two ray paths are converging, the
energy per crest length (wave action density) must increase, and the reverse
occurs for diverging paths. Because of refraction, ray paths converge to ridges
and diverge in gullies; the resulting change of energy influences the sedimentary regime.
recruitment "upgrowth", term used in population biology for the appearance of
the young in a given population per unit of time. The term is also used in a
slightly different way, i.e., not referring to the natural population in a given
260
(III) cation exhibit the same electron configuration, hence the very similar
physical and chemical properties. The gradual filling with electrons of the 14
positions in the inner 4f shell leads to a gradual change in properties with
increasing atomic number. At exactly half fIlled 4f shell, as for gadolinium
(Gd), energetic advantage may yield anomalous properties. Concentrations
in seawater ranging from about 10 pmoll- 1 (57La) down to about 0.1 pmoll-1
(71Lu). When normalized to crustal abundance the seawater values increase
gradually with increasing atomic number. The isotopic signature of
neodymium (Nd) varies between ocean basins. Exist in trivalent (III) cationic oxidation state in nature, except for cerium (Ce) and europium (Eu), which
may also occur in tetravalent (IV) and divalent (II) oxidation states.
Rattlesnake Expedition (1846-1850) this ship was sent to the south -western Pacific
under Captain Owen Stanley to continue surveying work particularly for a
safe ships route through the Torres Strait and the Great Barrier Reef. Extensive
surface and subsurface temperature measurements were carried out by Joseph
Dayman using self-registering maximum and minimum thermometers.
Marine collections were made by John MacGillivray (naturalist) and Thomas
Henry Huxley (assistant surgeon and naturalist). The voyage had profound
influence on T.H. Huxley [comparable to that of the Beagle on C.R. Darwin
(~Beagle Expedition)]. It started Huxley's life-long interest in comparative morphology. His diary of the cruise was edited in 1935 by his grandson.
Rayleigh number a nondimensional number, Ra, named after the British physicist Lord Rayleigh (1842-1919), that gives the ratio between the buoyancy
force and the combined opposing effects of viscosity and diffusive transport
of buoyancy. If the Rayleigh number exceeds a certain critical value, the fluid
becomes unstable and convection sets in. Usually the buoyancy will result
from heating, and the thermal expansion coefficient is incorporated in Ra,
but when buoyancy is connected with salinity differences (as in estuaries), the
volume contraction coefficient for salinity will be incorporated in a Rayleigh
number for salinity.
ray path is a line following the propagation direction of the waves, and is everywhere perpendicular to the wave crests. Between two adjacent ray paths the
available wave energy is conserved. So, if two ray paths are converging, the
energy per crest length (wave action density) must increase, and the reverse
occurs for diverging paths. Because of refraction, ray paths converge to ridges
and diverge in gullies; the resulting change of energy influences the sedimentary regime.
recruitment "upgrowth", term used in population biology for the appearance of
the young in a given population per unit of time. The term is also used in a
slightly different way, i.e., not referring to the natural population in a given