IS-95, an interim standard proposed for future digital personal communications
systems, uses two levels of encoding of digital data for error control and compatibility
with code-division multiple access (CDMA) transmission. The data is first
convolutionally encoded and the resulting symbols are interleaved and then groups are
encoded as orthogonal Walsh...
The kernel subtraction method of Kantorovich and Krylov is
studied in the setting of "Collectively Compact Operator Approximation
Theory." Fredholm integral equations of the second kind have
weakly singular kernels smoothened by a simple manipulation. This
allows for accurate numerical estimates of low order. The method
is first explained in...
Two numerical methods are presented that can be used to solve
second order nonlinear ordinary differential equations with periodic
boundary conditions. One of these methods is a shooting method developed
solely for the periodic problem. The other, "quasilinearization,"
is a method applicable to a wide variety of problems. It is...
The increasing knowledge of the significance of vitamin B₆ in
human metabolic processes has emphasized the importance of developing
reliable means of assessing nutritional status with respect to
this vitamin. One possible approach to this end is the measurement
of pyridoxal phosphate in blood or plasma, particularly since this
phosphorylated...
Food webs consist of a combination of bottom-up (resource-driven) and top-down (predator-driven) effects. The strength of these effects depends on the context in which they occur. I investigated food web (trophic) relationships between wolf (Canis lupus) predation, elk (Cervus elaphus) herbivory, aspen (Populus tremuloides Michaux) recruitment, and fire. The study...
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David E. Hibbs
Food webs consist of a combination of bottom-up (resource-driven) and top
Cooperative behaviors in bacteria are increasingly appreciated for their relevance to microbial ecology and utility as model systems for social evolution. One example is the secretion of siderophores, a structurally diverse group of compounds that chelate extracellular iron. Siderophore production is considered cooperative because the benefits can be shared with...
The use of radioactive isotopes as tracers in biological systems
has become widespread since the close of World War II. Proper
use of radiotracers requires a fundamental understanding of the physical
nature of radioactivity, the characteristics of ionizing radiation,
and the various methods available for measuring radioactivity.
More importantly, the...