16 research outputs found
Population ecology of Psammobates oculifer in a semi-arid environment
We studied the ecology of Psammobates oculifer over 13 months near Kimberley, South Africa, to ascertain if the population’s life history traits conform to chelonian patterns in arid environments. Capture rates were highest in spring and lowest in winter when environmental conditions were respectively most and least favourable for tortoise activity. Body condition did not change from autumn to spring, but reached lower values during the summer drought. Capture effort averaged 5 hours/tortoise, which corresponds closely to that of species with low population densities in arid regions. Population size structure was skewed towards adults, indicative of low recruitment and/or low juvenile survivorship. Females were larger and heavier than males, confirming sexual dimorphism in this species. Body size of cohorts scaled to annuli counts, indicating a close correspondence between body size and age. Telemetered adults deposited one or no growth ring in the year of study; consequently, annuli counts could underestimate adult age. Regression analyses showed that male and female growth rates did not differ, but males matured at a smaller size and younger age than females. The smallest male showing reproductive behaviour had 12 annuli and a shell volume of 157 cm3, while similar measures for females were 14 annuli and 185 cm3. The sex ratio of the population did not differ from 1:1 but the bias towards males in spring, and towards females in autumn, indicates that studies limited to particular seasons can misrepresent life history traits of populations. We concluded that the life history of P. oculifer conforms to chelonian patterns in arid regions.Web of Scienc
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United States Bureau of Mines Bulletin 516
From Forward: "This bulletin is the first of a new series, which includes analyses of only tipple and delivered coal. It covers samples collected throughout the United States from July 1, 1947 to June 30, 1950 (fiscal years 1948-50). It is planned that future publications of this series will cover a period of one fiscal year only and be issued as soon as possible after June 30 of each year.
Analyses of tipple and delivered samples of coal : collected during fiscal year 1966 /
Includes index.Mode of access: Internet
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United States Bureau of Mines Bulletin 572
From Washington Coalfields: The geographical distribution of the principal coal areas of Washington is shown in figure 1. Detailed information concerning these fields is given in Bureau of Mines Technical Paper 491. Further information on the minor coal areas is given in two bulletins of the Washington Division of Mines and Geology. Analyses, plastic properties, free-swelling indexes, and agglutinating values of the separate coals, together with data on yields of carbonization products and properties of the cokes produced in laboratory tests and under operating conditions.