UNLABELLED The ability to reduce atmospheric nitrogen (N2) to ammonia, known as N2 fixation, is a widely distributed trait among prokaryotes that accounts for an essential input of new N to a multitude of environments. Nitrogenase reductase gene (nifH) composition suggests that putative N2-fixing heterotrophic organisms are widespread in marine bacterioplankton, but their autecology and ecologi...

The net impact of human nitrogen (N) fixation on climate (ignoring short-lived components) mainly depends on the magnitude of the warming effect of (direct and indirect) nitrous oxide (N2O) emissions and the cooling effect of N-induced carbon dioxide (CO2) uptake. N-induced CO2 uptake is caused by anthropogenic N deposition which increases net primary production (NPP) in N-limited ecosystems an...

Much of the demand for nitrogen (N) in cereal cropping systems is met by using N fertilisers, but the cost of production is increasing and there are also environmental concerns. This has led to a growing interest in exploring other sources of N such as biological N2 fixation. Non-symbiotic N2 fixation (by free-living bacteria in soils or associated with the rhizosphere) has the potential to mee...

After peanuts and cowpeas ( Vigna unguiculata ), the Bambara groundnut subterranea (L.) Verdc) is third most significant food legume in Africa. It characteristically grown marginal soils, drought tolerant, also has potential for nitrogen fixation. Despite that, year-on-year yields are on a gradual decline due to combination of abiotic biotic stresses such as uneven annual rainfall climate-induc...

The microbiome of plants is diverse, and like that of animals, is important for overall health and nutrient acquisition. In legumes and actinorhizal plants, a portion of essential nitrogen (N) is obtained through symbiosis with nodule-inhabiting, N2-fixing microorganisms. However, a variety of non-nodulating plant species can also thrive in natural, low-N settings. Some of these species may rel...

Diffusion methods were used to investigate the fixation probability, average time until fixation and extinction, and cumulative heterozygosity and genetic variance for single mutant genes in finite populations with partial inbreeding. The critical parameters in the approximation are the coefficient of inbreeding due to nonrandom mating (F) and the effective population size (Ne), which also depe...

In prior work, we observed that soybean (Glycine max L. cv Merr.) seeds inoculated with a mutant Bradyrhizobium japonicum strain unable to catabolize Pro (Pro dehydrogenase(-) [ProDH(-)]) resulted in plants that, when forced to depend on N(2) fixation as the sole source of nitrogen and subjected to mild drought stress, suffered twice as large a loss in seed yield as did plants inoculated with t...

The effects of P deficiency on growth, N(2)-fixation and photosynthesis in white clover (Trifolium repens L.) plants were investigated using three contrasting relative addition rates of P, or following abrupt withdrawal of the P supply. Responses to a constant below-optimum P supply rate consisted of a decline in N(2)-fixation per unit root weight and a small reduction in the efficiency with wh...

Vertical sacral fracture is one of the most difficult fractures to treat. Posterior fixation using spinal dual rods is a novel method for treating this fracture, but its biomechanical strength has not yet been reported. The aim of this study was to evaluate the biomechanical strength produced by posterior fixation using spinal instrumentation. Sacral fractures were created in eight pelvic bone ...

PURPOSE To conduct a prospective randomised controlled study to compare the stability and risk of nerve injury between fractures treated by medial-lateral pin fixation and those treated by 2-lateral pin fixation. METHODS Patients with displaced supracondylar fractures admitted between May 2000 and December 2001 were recruited into the study. They were randomised to treatment either with media...