Environmental Changes Produced by Cold-Water Outlets from Three Arkansas Reservoirs

Water qualities of two natural streams (Buffalo and Kings Rivers), one new coId-tailwater (Beaver), and two old coId-tailwaters (Norfork and Bull Shoals) in northwestern Arkansas were studied from July 1965 through October 1968. The essential difference between the old cold-tailwaters and natural streams is a change in water quality which allows the development of a new productive ecological environment. Features which typify the old tailwaters are as follows: (1) relatively homioithermal temperatures; (2) stream beds scoured by strong hydoelectric power generation currents; (3) abundant phytoplankton and benthic macroinvertebrates; and (4) absence of warm water game fishes. Environmental factors characterizing natural streams are as follows: (1) high summer temperatures; (2) seasonal and individual current fluctuations at the various stations; (3) a greater variety of benthic macroinvertebrates and ichthyofauna; (4) abundant zooplankters; and (5) a tendency toward an equal distribution of the phyla Chrysophyta, Cyanophyta, and Chlorophyta. By October 1968, the new Beaver coId-tailwater had lost all of its warm-water characteristics but had not developed the biotic features of the old tailwaters

Off-lattice Monte Carlo Simulation of Supramolecular Polymer Architectures

We introduce an efficient, scalable Monte Carlo algorithm to simulate cross-linked architectures of freely-jointed and discrete worm-like chains. Bond movement is based on the discrete tractrix construction, which effects conformational changes that exactly preserve fixed-length constraints of all bonds. The algorithm reproduces known end-to-end distance distributions for simple, analytically tractable systems of cross-linked stiff and freely jointed polymers flawlessly, and is used to determine the effective persistence length of short bundles of semi-flexible worm-like chains, cross-linked to each other. It reveals a possible regulatory mechanism in bundled networks: the effective persistence of bundles is controlled by the linker density.Comment: 4 pages, 4 figure

Weighting Miscues in Informal Inventories: A Precautionary Note

Even among those who are not readily in agreement with the numerous implications for instruction being put forward in the name of a psycholinguistic model of reading, there is substantial support for the constructive dialogue and spirited interactions which have been generated. The enthusiasm of some, however, has, at times, been taken to such extremes that the reality of the classroom has all but been ignored. Recently, for example, my students encountered some difficulty in reconciling certain practical applications of miscue techniques with another fundamental precept of reading instruction; that is, the critical role of successful practice in connected reading toward the development of proficiency. This conflict is disturbing. Whether these concerns are real or imagined, significant or inconsequential is the topic of this brief presentation