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...

We study a discrete time model of the growth of two species of plankton with competitive and allelopathic effects on each other N1(k + 1) = N1(k)exp{r1(k)− a11(k)N1(k)− a12(k)N2(k) − b1(k)N1(k)N2(k)}, N2(k + 1) = N2(k)exp{r2(k) − a21(k)N1(k) − a22(k) N2(k)− b2(k)N1(k)N2(k)}. A set of sufficient conditions is obtained for the existence of multiple positive periodic solutions for this model. The ...

We measured N2 fixation rates from oceanic zones that have traditionally been ignored as sources of biological N2 fixation; the aphotic, fully oxygenated, nitrate (NO(-) 3)-rich, waters of the oligotrophic Levantine Basin (LB) and the Gulf of Aqaba (GA). N2 fixation rates measured from pelagic aphotic waters to depths up to 720 m, during the mixed and stratified periods, ranged from 0.01 nmol N...

Different modified atmosphere conditions with various CO2 concentrations on microbial load (psychrophile, mesophile aerobic and anaerobic bacteria) and physico-chemical properties of barramundi (Lates  calcarifer Bloch) fillets stored at 8°C were compared to determine the best packaging conditions. The gas conditions evaluated were 100% CO2 (M1), 75% CO2/25% N2 (M2), 50% CO2/50% N2 (M3), 25% CO...

In this paper we present the results of a study of the electron cooling rate, the production rates of vibrationally excited N2…v†, and the production frequency of the N2 vibrational quanta arising from the collisions of electrons with unexcited N2…0† and vibrationally excited N2…1† molecules as functions of the electron temperature. The electron energy transfer rates for vibrational excitation ...

Minor millets are examples of underutilized plant species, being locally important but rarely traded internationally with an unexploited economic potential. In the Kolli hills of Tamil Nadu, India, a genetically diverse pool of minor millet varieties are grown by the tribal farming communities to meet their subsistence food needs. Most of these minor crops were not traded outside the farming co...

Background: Natural radionuclides in rock samples, primarily 238U (uranium), 232Th (thorium) and 40K (potassium), are the main source of radiation exposure to workers and general public and their measurement is of paramount importance from radiation protection point of view. Materials and Methods: Gamma spectrometry using HPGe detector was used to measure the radioactivity and assess the radiol...

Extensive habitat loss and changing agricultural practices have caused widespread declines in grassland birds throughout North America. The Flint Hills of Kansas and Oklahoma--the largest remaining tallgrass prairie--is important for grassland bird conservation despite supporting a major cattle industry. In 2004 and 2005, we assessed the community, population, and demographic responses of grass...