37 research outputs found
A study of the decay of 187W using a 2 m curved-crystal spectrometer
The gamma rays in the decay of 187W have been studied using the University of Michigan 2 m curved-crystal spectrometer and a lithium-drifted germanium diode spectrometer. One previously unreported transition has been observed and the energies of all observed transitions have been determined with the curved-crystal spectrometer. Upper limits have been determined for the intensities of possible unobserved gamma rays in the 160-1200 keV region. The relative merits and complementarity of the curved crystal spectrometer and the Ge(Li) spectrometer are discussed. In addition, data are presented concerning the reflectivity of the curved crystal using the germanium planes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33458/1/0000862.pd
Simulating feedback and reversibility in substrate-enzyme reactions
We extend discrete event models (DEM) of substrate-enzyme reactions to include regulatory feedback and reversible reactions. Steady state as well as transient systems are modeled and validated against ordinary differential equation (ODE) models. The approach is exemplified in a model of the first steps of glycolysis with the most common regulatory mechanisms. We find that in glycolysis, feedback and reversibility together act as a significant damper on the stochastic variations of the intermediate products as well as for the stochastic variation of the transit times. This suggests that these feedbacks have evolved to control both the overall rate of, as well as stochastic fluctuations in, glycolysis