Polar lightning and decadal-scale cloud variability on Jupiter

Although lightning has been seen on other planets, including Jupiter, polar lightning has been known only on Earth. Optical observations from the New Horizons spacecraft have identified lightning at high latitudes above Jupiter up to 80 degrees N and 74 degrees S. Lightning rates and optical powers were similar at each pole, and the mean optical flux is comparable to that at nonpolar latitudes, which is consistent with the notion that internal heat is the main driver of convection. Both near-infrared and ground-based 5-micrometer thermal imagery reveal that cloud cover has thinned substantially since the 2000 Cassini flyby, particularly in the turbulent wake of the Great Red Spot and in the southern half of the equatorial region, demonstrating that vertical dynamical processes are time-varying on seasonal scales at mid- and low latitudes on Jupiter.     

Cowpea rhizobia: Comparison of plant infection and plate counts

Enumeration of Rhizobium in soil is usually accomplished by the most probable number (MPN) plant infection method. The accuracy of MPN counts as compared to plate counts was determined for five strains of cowpea rhizobia. Host plants included cowpea (Vigna unguiculata (L.) Walp.), siratro (Macroptilium atropurpureum (DC.) Urb.) and peanut (Arachis hypogaea L.). Plastic growth pouches were used primarily for cowpea and siratro while plastic cups containing vermiculite were used for peanut. The number of rhizobia determined by the MPN method using cowpea, siratro and peanut underestimated the population from 10- to 100-fold. A control experiment using soybeans (Glycine max (L.) Merrill) indicated that the MPN method was accurate for R. japonicum. Experimentors using the MPN method should be aware of its accuracy for particular Rhizobiutn-legume combinations.     

Fertilization and Bioaugmentation for Oil Biodegradation in Salt Marsh Mesocosms

Biodegradation of crude oil is often dependent on the population sizes and metabolic activity of hydrocarbon-degrading microorganisms in addition to nutrient supply. Fertilization with N and P and bioaugmentation of oil-contaminated soil with hydrocarbon-degrading microorganisms may serve to enhance oil biodegradation rates. Glasshouse experiments were conducted to determine the impacts of fertilization and commercial bioremediation products on crude oil biodegradation and on changes in nutrient concentrations and populations of hydrocarbon-degrading microorganisms in salt marsh mesocosms growing Spartina alterniflora. Experiments were conducted under continuously-flooded and alternately-flooded/drained conditions with and without N and P fertilization. MaxBac, a slow-release fertilizer, was applied at a rate of 100 kg N ha^-1 and 20 kg P ha^-1, while additional P was applied at 20 kg P ha^-1. Commercial products failed to enhance total oil or total petroleum hydrocarbon (TPH) degradation under either continuously or alternately-flooded conditions. An average of 62% of TPH was degraded by 33 d under continuously-flooded conditions, while 59% was degraded by 41 d after oil application under alternately-flooded conditions. Products generally did not increase population sizes of heterotrophs orhydrocarbon-degrading microorganisms. Concentrations of NH₄ ⁺ and P decreased during experimentation, and fertilization with N and P stimulated total oil and TPH degradation under continuously-flooded, but not under alternately-flooded conditions.     

Demographic studies on final year veterinary students of nine European schools

In 1975 a survey of some aspects of veterinary student selection, background and education as well as intended employment after qualification was conducted in the veterinary schools at Bristol, Glasgow, Liverpool, Helsinki, Stockholm, Hannover, Ghent, Toulouse and Vienna. In all schools student selection was primarily based on academic ability. A numerus clausus existed in six of the nine schools. No sex discrimination in student selection was practised in seven of the nine schools. The proportion of male students in the final year of 1975 ranged from 57 per cent in Glasgow to 97 per cent in Ghent. The parents of the students were predominantly of socioeconomic classes 1 (28 per cent), 2 (38 per cent) or 3 non manual (20 per cent), and no significant differences were found between the UK and the continental schools. Six per cent of the parents were veterinarians while 15 per cent were farmers. The financing by students of their veterinary studies varied markedly between schools. Over 80 per cent of the students wished to go first into general practice, with little tendency, except among UK students, to go into employment abroad first.     

Sulfur influences on rumen microorganisms in vitro and in sheep and calves

When continuously cultured ruminal microbes were given orchardgrass hay and sufficient sulfuric acid or hydrochloric acid to maintain a pH of 5.5, fermentation and numbers of protozoa were reduced compared with cultures whose pH was controlled with phosphoric acid. Likewise, when sulfur-deficient, purified diets were supplied to cultures, less methane (mmol X liter-1 X d-1), 3.2 vs 32.6, was produced and fewer cellulolytic bacteria (log10/ml), 5.8 vs 7.2 were present than when cultures were given the same diet supplemented with .3% elemental sulfur. The rumen of sheep fed the .04% sulfur diet had reduced digesta weights (1.69 vs 3.2 kg) compared with sheep fed the diet with .34% sulfur at the same intake. There also was reduced methanogenesis 12.3 vs 25.8 mmol X liter-1 X d-1) and reduced numbers of cellulolytic bacteria (7.4 vs 8.4 log10/ml) in sulfur-deficient sheep in comparison to sulfur-supplemented sheep. In growing calves, the same types of bacteria predominated in the rumen, but more facultative anaerobic bacteria were isolated from calves fed .04% sulfur than from calves fed diets with .34 to 1.72% sulfur. None of the dietary levels of sulfur appeared toxic. Regardless of treatment, volatile fatty acids were more predominant than lactic acid as end-products of fermentation of ruminal microbes in fermenters, sheep and calves. The greater methanogenesis and the greater cellulolytic bacterial numbers of sulfur-supplemented sheep compared with sulfur-deficient in vitro cultures, is interpreted to be the result of recycling of sulfur to the rumen in sheep where it is efficiently scavengered by ruminal bacteria.