[1] In this paper we use a biological-physical model with an explicit representation of Trichodesmium to examine the influence of N2 fixation in the Atlantic. Three solutions are examined, one where the N2 fixation rate has been set to observed levels, one where the rate has been increased to levels comparable to geochemical estimates, and one with no N2 fixation. All solutions are tuned to rep...

We analyzed the metabolic rhythms and differential gene expression in the unicellular, diazotrophic cyanobacterium Cyanothece sp. strain ATCC 51142 under N(2)-fixing conditions after a shift from normal 12-h light-12-h dark cycles to continuous light. We found that the mRNA levels of approximately 10% of the genes in the genome demonstrated circadian behavior during growth in free-running (cont...

Alder plays an important role in the nitrogen (N) economy of boreal forests because of its high capacity for atmospheric N fixation. Range expansion and increased insect and/or pathogen attack are two potential consequences of climate change that may result in significant, albeit opposite, effects on these systems through influences on alder-mediated N inputs. This study contrasted the effects ...

BACKGROUND Effective soft tissue graft fixation to the tibial tunnel in all-inside anterior cruciate ligament reconstructions has been reported to be a problem and may lead to retrograde pullout at ultimate load testing. HYPOTHESIS A combined retrograde bioabsorbable screw and cortical-cancellous suture button suspension apparatus would gain stiffness from the button and strength from the scr...

In temperate Atlantic waters (18.8 to 20.1°C), biological nitrogen fixation has been demonstrated by 2 independent measurements: N-N2 incorporation and nifH identification in the DNA and expressed messenger RNA (mRNA). At 2 stations in the western English Channel, bulk waters were incubated with N-N2. At the high levels of particulate nitrogen (≤11.5 μmol N l–1), absolute fixation rates of 18.9...

PURPOSE To study the biomechanical characteristics (percent stretch, stiffness, and ultimate load) of 2 distal fixation techniques for an active tendon implant used in the reconstruction of flexor tendons. METHODS We evaluated percent stretch after cyclical loading and at failure, stiffness during load-to-failure, and peak load of 28 bone-prosthesis junctions using cadaveric canine middle pha...

Introduction Symbiotic N fixation inhibition induced by supply to legumes is potentially regulated the relative and P availability in soil. However, specific responses of different legume species changes N:P remain unclear, must be better understood optimize symbiotic inputs under enrichment. This study investigated mechanisms which soil influence eight species, quantify inter-specific differen...

Heat evolved by isolated soybean (Glycine max cv Clark) nodules was measured to estimate more directly the metabolic cost associated with the symbiotic N(2) fixation system. A calorimeter constructed by modifying standard laboratory equipment allowed measurement on 1 gram of detached nodules under a controlled gas stream. Simultaneous gas balance and heat output determinations were made.There w...

The objectives of this study were to count and culture Azotobacter spp. in sampled soils, to determine the nitrogen (N) fixing capacity byAzotobacter spp. in pure culture and different soils, and to explore the relationships between N fixation capacity of Azotobacter spp. and microbiological properties of soils in Northern Anatolia, Turkey. Statistically significant relationships were found bet...