Microbial mobilization of barite

Bacteria from lake mud grown under anaerobic conditions with powdered barite present significantly increase the amount of barium that dissolves in the culture medium. Innocula of lake mud were added to a growth medium specified for sulfate-reducing bacteria. Powdered barite was added to each culture flask and flasks were purged with nitrogen, sealed and maintained at 20°C for 17 days. When the cultures were opened for analysis, hydrogen sulfide and iron sulfide had formed in all growing cultures. In cultures containing barite as the only sulfate, the barium content of the culture solutions had risen to an average of 3.3 ppm (maximum = 3.8 ppm, minimum = 1.8 ppm). Cultures containing ferrous sulfate and barite showed less than 0.1 ppm barium in solution. Cultures that had been sterilized by poisoning or autoclaving showed approximately 0.5 ppm barium in solution. Sulfate-reducing bacteria may be responsible for the high barium concentrations recorded in streams draining barite mining areas.     

Mid-eclipse brightening of the Galilean satellites

Brinkmann (1973) has suggested that the Galilean satellites might briefly manifest a brightening at mid-eclipse due to a concentration of light refracted into the geometric umbra of Jupiter by the atmosphere around the terminator. Results obtained using two different models of the Jovian atmosphere indicate that such a brightening is unlikely even for Callisto due to the probable aerosol concentration in the Jovian atmosphere at the relevant altitudes.     

THE USE OF AIRBORNE AUXILIARY DATA IN THE RIGOROUS LEAST SQUARES ADJUSTMENT OF A BLOCK OF AERIAL TRIANGULATION

The problem of incorporating airborne auxiliary data into an aerial triangulation block adjustment is considered. The conclusion is reached that this problem can be most readily solved by the use of a fully rigorous adjustment method. The first order adjustment equations for all types of airborne auxiliary control are developed and the method of incorporating these equations into the block solution is demonstrated. The general computing problems of the aerial triangulation block adjustment are briefly discussed and a method outlined for the incorporation of tie strips, at any angle across the block, into the adjustment without unduly increasing the storage requirements for the solution. The problem of correctly weighting the different types of available data is discussed. The paper concludes with a demonstration of the improved accuracy possible if precise aerial triangulation data are combined with apparently crude absolute airborne data.     

A faint object spectrometer for the infrared

A cryogenic astronomical spectrometer for the NASA Infrared Telescope Facility is described. This spectrometer will employ an array of at least 20 detectors and provide a resolving power of 100 to 1500 at 1–5 m. The resolving power will be adjustable by changing gratings.Paper presented at the IAU Third Asian-Pacific Regional Meeting, held in Kyoto, Japan, between 30 September–6 October, 1984.