A technique to determine which nutrients limit bacterial growth in soil was developed. The method was based on measuring the thymidine incorporation rate of bacteria after the addition of C, N, and P in different combinations to soil samples. First, the thymidine incorporation method was tested in two different soils: an agricultural soil and a forest humus soil. Carbon (as glucose) was found t...

Arizona sycamore (Platanus wrightii: Platanaceae) is a riparian tree of the southwestern United States and adjacent Mexico. It is failing to reproduce in certain canyons where mature, seed-producing trees of this species occur. Three hypotheses were tested to explain this reproductive failure: I) the presence of domestic cattle prevents reproduction, 2) seeds produced in certain canyons are inv...

By variation of nutritional and other external conditions we have determined the factors that limit the multiplication rate and the culture growth in Tetrahymena thermophila. The enriched synthetic medium of Kidder & Dewey (1951), a culture temperature of 29 degrees C, and aeration by agitation were chosen as reference conditions. The final cell density is increased by and proportional to the a...

S. S. Bulanov, E. Esarey, C. B. Schroeder, S. V. Bulanov, 3 T. Zh. Esirkepov, M. Kando, F. Pegoraro, and W. P. Leemans 5 Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA QuBS, Japan Atomic Energy Agency, Kizugawa, Kyoto, 619-0215, Japan A. M. Prokhorov Institute of General Physics RAS, Moscow, 119991, Russia Physics Department, University of Pisa and Istituto Nazionale di ...

Contrast detection is impaired in amblyopes. To understand the contrast processing deficit in amblyopia, we studied the effects of masking noise on contrast threshold in amblyopic macaque monkeys. Amblyopia developed as a result of either experimentally induced strabismus or anisometropia. We used random spatiotemporal broadband noise of varying contrast power to mask the detection of sinusoida...

BACKGROUND After lung transplantation (LTx) exercise capacity frequently remains limited, despite significantly improved pulmonary function. The aim of this study was to evaluate maximal exercise capacity and peripheral muscle force before and 1 year after LTx, and to determine whether peripheral muscle force and lactate threshold (LT) limit exercise capacity 1 year after LTx. METHODS Twenty-...

1. Maximal exercise capacity in cystic fibrosis is influenced by both pulmonary and nutritional factors: lung disease by limiting maximal achievable ventilation, and malnutrition through a loss of muscle mass. The associated reduction in everyday activities may result in peripheral muscle deconditioning. 2. We studied 14 stable patients with cystic fibrosis (six males, eight females) and 14 hea...

Consensus is growing that agriculture is vulnerable to climate change and adaptation responses are necessary to minimize impacts. Nonetheless, the diversity of potential impacts, agro-ecological contexts and regional capacity for change make understanding adaptation behaviors challenging and ensure that climate change adaptation will not be the same across all contexts. Considering this heterog...

~ 113-The histochemical reaction of choline dehydrogenase was completely inhibited by the pretreatment of cryostat sections with either absolute acetone or lO<yo water-in-acetone at room temperature (25°C). The temperature of the organic solvents was critical in the inhibition of the staining for choline dehydrogenase. As the temperature was lowered, the inhibitory effects of the pretreatment d...

1. Extensive measurements have been obtained (a) relating photosynthesis and light intensity for a large range of CO(2) concentrations and (b) relating photosynthesis and CO(2) at different light intensities. From these families of curves, the limiting factor relationship can be secured for any value of the photosynthesis rate. 2. In terms of previous work an equation has been derived for descr...