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Notes: Summary. Between 1964 and 1984, 2011 patients in the West of Scotland were treated by radical radiotherapy for carcinoma of cervix. In keeping with the rise in incidence amongst younger patients nationally, the number of women aged 〈35 years seen during the 20-year period has doubled. Younger women (aged 〈35 or 〈45) have a better prognosis mainly because more present with earlier disease. Stage for stage there has been no change in survival of women of all ages treated by identical radiotherapy during this period. The rise in mortality of younger patients from carcinoma of cervix may be due to the increased incidence of the condition rather than a more virulent form of the disease.

Notes: Experiments were carried out to investigate strong traps (binding enthalpies〉0.50 eV) for deuterium that were found earlier when pure nickel was implanted with argon and krypton at temperatures ≤500 °C. In one experiment, three different areas of a nickel specimen were implanted with a fluence of 2×1016 cm−2 krypton at 600, 700, and 800 °C; a second experiment involved implanting krypton at three different fluences (2, 6, and 20×1015 cm−2) in nickel at 500 °C. Retained deuterium was monitored during subsequent isochronal anneals using nuclear reaction analysis. In a third experiment, depth profiles for both implanted krypton and trapped deuterium were determined simultaneously using secondary ion mass spectrometry. Traps for deuterium in krypton-implanted nickel were found with binding enthalpies ranging from 0.5 to 1.1 eV. At implantation temperatures 〈500 °C, the traps are in the same location as the krypton atoms. At implantation temperatures 〉700 °C, the traps are found where the krypton was originally implanted in spite of the fact that a significant fraction of the krypton apparently escapes through the surface during the implantation process. The observed fluence and temperature dependence indicate that the traps with binding enthalpies between 0.5 and 1.1 eV are associated with the surfaces of cavities formed during the implantation.

Notes: MISCELLANEOUS NOTES

Notes: BOOK REVIEWS

Notes: Abstract Laboratory experiments near 1450° C at 1 bar (QFM) on komatiite bulk composition show olivine and liquid in cumulus textures which evolve with experiment duration. Orthocumulus texture with settled olivine crystals separated by liquid matrix is developed within a day. Experiments quenched after a few days to a week show a progression of textures which include development of columns of olivine crystals separated by channels of liquid. Olivine grain sizes increase with the cube root of time suggesting that dissolution and reprecipitation of olivine may be involved in the organization into columns and channels. Experiments quenched after two weeks have well developed adcumulus texture. The basal polycrystalline granular olivine aggregate forms from the decay of the olivine columns. Melt expulsion from the aggregate can be virtually complete, leaving 1% or less of the melt originally present. Buoyancy-driven compaction of olivine is not the mechanism responsible for this textural evolution because the final basal aggregate sometimes contains vesicles. An addition proof of the inadequacy of buoyancy is provided by raising the crucible slightly above the thermal symmetry point of the furnace. The aggregate then compacts on top of a crystal-free liquid. The thermal gradients above and below the furnace hot spot are thought to be primarily responsible for the olivine redistributions observed. Diffusion of olivine components in the liquid is driven along a saturation gradient resulting from the temperature gradient. The process, called thermal migration in geological literature, is essentially the same as traveling solvent zone refining in metallurgy. Differential solubility and Soret fractionation both contribute to olivine redistribution to the cold region of the crystal-liquid aggregate. There may be some applications of these results to natural cumulate rock petrogenesis.

Notes: Abstract Diffusivities for calcium, iron, magnesium, manganese and aluminum have been measured for St. John's olivine undergoing cation exchange with synthetic basaltic melts. The variety of temperature, pressure and fO2 conditions under which the diffusivities were measured complement the equilibrium-partitioning study of calcium in olivine-bearing basalts by Jurewicz and Watson, 1988. Olivine was found to be anisotropic with respect to the diffusion of calcium, iron, magnesium and manganese. This anisotropy is a weak function of temperature, but strongly dependent upon oxygen fugacity. Because diffusion is independent of olivine composition over the small range of compositions used in this study, it could be shown that the absolute values of the diffusion coefficients were also functions of temperature and fO2. At near-atmospheric total pressure and an oxygen fugacity of 10−8atm, D Fe〉D Mn〉D Ca and D Mg≥D Mn for a range of geologically reasonable temperatures. These relative diffusivities were shown to change with oxygen fugacity. The power-law dependence of diffusion on oxygen partial-pressure was determined for each cation and the results are consistent with the range of values given by Stocker (1978) and by other workers. For Ca and Fe, the effect of hydrostatic pressure on diffusion appears to be weak, at least for transport parallel to the c crystallographic direction. Unfortunately, no true activation volumes (or other pressure-related parameters) could be computed because the oxygen fugacity was not held constant over changes in pressure, and because accurate post-experiment reconstruction of sample orientation was not possible. Al was found to enter high-pressure olivines at concentrations of up to 0.14 weight percent, thus allowing aluminum diffusion to be characterized. The diffusivity of aluminum is, within error, the same as iron at 20 kb at 1430° C at the ambient fO2 of our piston-cylinder cells. This correspondence suggests that diffusion of Al may depend on transport of either Fe or of Fe +3 defects. While the results of these experiments are generally consistent with results published elsewhere, there are important inconsistencies. Tracer diffusion and interdiffusion in pure, ordered, olivine endmembers (e.g., tephroite and forsterite) showed significantly higher activation energies. This discrepancy could reflect the role of Fe+3 defects in diffusion; however, it may also suggest that order-disorder phenomena may be significant factors influencing diffusion in analog systems. The results of this study are applied to four petrologic problems: (1) calculation of rates of equilibration for olivine xenocrysts; (2) calculation of closure temperatures for the CaO/MgO olivine/basalt geothermometer (Jurewicz and Watson 1988); (3) delineation of an intrinsic-/O2 geobarometer; and (4) investigation of the dependence of olivine dissolution upon crystallographic orientation. In addition, it is demonstrated that diffusion-exchange experiments are useful for studying the dominant point-defect mechanisms for cation diffusion.