Field evaluation of sampling methods for pressurized geothermal liquids, gases, and suspended solids

Many different sampling methods were tested and compared for collecting samples for measurement of brine chemistry, gases, and suspended solids from pressurized geothermal systems. The tests were conducted on the 6-2 wellhead and a test loop at the Department of Energy's Geothermal Test Facility at East Mesa, California. The recommended methods for single-phase liquid or single-phase steam (with gases) are presented, together with detailed procedures. The results of testing methods for sampling two phase liquid-steam systems showed significant errors can result. It was recommended that two-phase flowing wells be directed to a full flow separator and the single-phase liquid and single-phase steam sampled separately using the recommended methods

A FURTHER EXAMINATION OF THE PRICE AND VOLATILITY IMPACT OF STOCK DIVIDENDS AT EX-DATES *

We examine the price and volatility reaction around stock dividend ex-dates for an Australian sample, over the period January 1992 to December 2000. We find that price reaction around stock dividend ex-dates provides positive abnormal returns both prior, and subsequent, to the abolishment of par value of shares in July 1998. When we partitioned the sample into financial, industrial non-financial and mining firms, the price reaction is found to be positive and significant only for industrial non-financial companies. Volatility of daily returns for periods subsequent to ex-dates is significantly greater than corresponding periods prior to announcement dates, while cumulative raw returns subsequent to ex-dates are significantly lower than periods prior to announcement dates for industrial non-financial companies. The magnitude of the price reaction is statistically significantly related to an increase in the volatility of daily returns and to a reduction in cumulative raw returns subsequent to the ex-dates, for industrial non-financial companies. These findings support buying pressure hypothesis suggested by Dhatt et al. (1994, 1996 ). Copyright Blackwell Publishing Ltd/University of Adelaide and Flinders University 2005..

Survival costs of reproduction are mediated by parasite infection in wild Soay sheep

A trade-off between current and future fitness potentially explains variation in life-history strategies. A proposed mechanism behind this is parasite-mediated reproductive costs: individuals that allocate more resources to reproduction have fewer to allocate to defence against parasites, reducing future fitness. We examined how reproduction influenced faecal egg counts (FEC) of strongyle nematodes using data collected between 1989 and 2008 from a wild population of Soay sheep in the St. Kilda archipelago, Scotland (741 individuals). Increased reproduction was associated with increased FEC during the lambing season: females that gave birth, and particularly those that weaned a lamb, had higher FEC than females that failed to reproduce. Structural equation modelling revealed future reproductive costs: a positive effect of reproduction on spring FEC and a negative effect on summer body weight were negatively associated with overwinter survival. Overall, we provide evidence that parasite resistance and body weight are important mediators of survival costs of reproduction