Jeffrey T. Walker

Learn More
The perceived duration of a short tone (1,000 or 1,500 msec) was longer than that of a separately presented light of equal length. Thus, when light and tone were presented simultaneously, there was a conflict in perceived duration. In that case, the perceived duration of an interval filled with both light and tone was close to that of an interval filled(More)
Ammonia-nitrogen #ux (NH -N"(14/17)NH ) was determined from six anaerobic swine waste storage and treatment lagoons (primary, secondary, and tertiary) using the dynamic chamber system. Measurements occurred during the fall of 1998 through the early spring of 1999, and each lagoon was examined for approximately one week. Analysis of #ux variation was made(More)
SummaryThe inheritance of resistance in Upland cotton to Xanthomonas malvacearum was investigated using a half diallel set of crosses between six inbred varieties. Parents and progeny were inoculated and examined at three sites: Shambat and Wad Medani in the Sudan, and Namulonge in Uganda. In the Sudan, leaves only were inoculated. At Namulonge leaves and(More)
The objective of this work was the development and validation of procedures designed to clean glass and stainless steel surfaces after exposure to the experimental anticancer drug, bisnafide. The cleaning procedures, using 5% acetic acid water, Alconox, and water, were validated using a wipe test and an HPLC method developed to quantitate low levels of(More)
In the fields of high-LET radiotherapy and space radiation safety it is important to know the relative probabilities with which a cell whose nucleus is struck by a heavy ion will be damaged or killed. Experiments were performed in which synchronous cultured human T-1 cells (presumptive HeLa) were irradiated with natural alpha particles of energy(More)
THE origin in 1947 of the modal bulk project in the Uganda Upland cotton variety BP52 was described by Manning (i 955, 1956). Manning's objective was to produce" a relatively stable check variety. as a basis for measuring advance achieved from selection in the replicated progeny row material" and he considered that this could be done by the successive(More)
High energy, high-Z (HZE) particles are present in high-altitude and high-inclination satellite orbits. Most of the HZE dose above LET = 200 keV/micrometer is due to Fe nuclei. Individual HZE particles can damage several cells adjacent to one another along the particle track in tissue. The outcome has been described as a "microlesion" by D. Grahn. The(More)
In this paper, we reported the results obtained from fitting a new growth model to serial height data of 80 Fels children. The model assumed that human height growth curves are due to the combined effects of six macroscopic logistic growth processes, each reaching the same asymptotic height value. It was named the Walker and(More)
Competition from the annual grass Bromus tectorum threatens aridland perennial bunchgrass communities. Unlike annuals, perennials must allocate part of their first year nitrogen (N) budget to storage rather than growth, potentially placing them at a competitive disadvantage. We evaluated N acquisition and conservation for two perennial bunchgrasses,(More)