Time series models of intraindividual varibility

Issued as final reportUnited States. Dept. of Health and Human Service

Fluctuations of the partial filling factors in competitive RSA from binary mixtures

Competitive random sequential adsorption on a line from a binary mix of incident particles is studied using both an analytic recursive approach and Monte Carlo simulations. We find a strong correlation between the small and the large particle distributions so that while both partial contributions to the fill factor fluctuate widely, the variance of the total fill factor remains relatively small. The variances of partial contributions themselves are quite different between the smaller and the larger particles, with the larger particle distribution being more correlated. The disparity in fluctuations of partial fill factors increases with the particle size ratio. The additional variance in the partial contribution of smaller particle originates from the fluctuations in the size of gaps between larger particles. We discuss the implications of our results to semiconductor high-energy gamma detectors where the detector energy resolution is controlled by correlations in the cascade energy branching process.Comment: 19 pages, 8 figure

Random sequential adsorption of shrinking or spreading particles

We present a model of one-dimensional irreversible adsorption in which particles once adsorbed immediately shrink to a smaller size or expand to a larger size. Exact solutions for the fill factor and the particle number variance as a function of the size change are obtained. Results are compared with approximate analytical solutions.Comment: 9 pages, 8 figure

Correlation effects in sequential energy branching: an exact model of the Fano statistics

Correlation effects in in the fluctuation of the number of particles in the process of energy branching by sequential impact ionizations are studied using an exactly soluble model of random parking on a line. The Fano factor F calculated in an uncorrelated final-state "shot-glass" model does not give an accurate answer even with the exact gap-distribution statistics. Allowing for the nearest-neighbor correlation effects gives a correction to F that brings F very close to its exact value. We discuss the implications of our results for energy resolution of semiconductor gamma detectors, where the value of F is of the essence. We argue that F is controlled by correlations in the cascade energy branching process and hence the widely used final-state model estimates are not reliable -- especially in the practically relevant cases when the energy branching is terminated by competition between impact ionization and phonon emission.Comment: 11 pages, 4 figures. Submitted to Physical Review

Report of the sensor readout electronics panel

The findings of the Sensor Readout Electronics Panel are summarized in regard to technology assessment and recommended development plans. In addition to two specific readout issues, cryogenic readouts and sub-electron noise, the panel considered three advanced technology areas that impact the ability to achieve large format sensor arrays. These are mega-pixel focal plane packaging issues, focal plane to data processing module interfaces, and event driven readout architectures. Development in each of these five areas was judged to have significant impact in enabling the sensor performance desired for the Astrotech 21 mission set. Other readout issues, such as focal plane signal processing or other high volume data acquisition applications important for Eos-type mapping, were determined not to be relevant for astrophysics science goals

Ambient Salinity and the Daily Variation of Circulating Prolactin in the Gulf Killifish Fundulus grandis

Gulf killifish were maintained in either 3‰ or 35‰ commercial sea salts on a LD 12:12 photoperiod regime and sampled by heart puncture at one of 6 different times of day. Maximum titers of circulating prolactin occurred at the same time of day (8h after light onset) in fish acclimated to either 3‰ or 35‰. Fish acclimated to 3‰ had an additional increase in serum prolactin (8h after light offset) not noted in 35‰ acclimated fish