Higher Algebra

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Simulation levels of detail for plant motion

In this paper we describe a method for simulating motion of realistically complex plants interactively. We use a precomputation stage to generate the plant structure, along with a set of simulation levels of detail. The levels of detail are made by continuously grouping branches starting from the tips of the branches and working toward the trunk. Grouped branches are simulated as single branches that have similar simulation characteristics to the original branches. During run-time, we traverse the plant and determine the allowable error in the simulation of branch motion. This allows us to choose the appropriate simulation level of detail and we provide smooth transitions from level to level. Our level of detail approach affects only the simulation parameters, allowing geometry to be handled independently. Using this method we can significantly improve simulation times for complex trees

The Humanization of the Teaching of Mathematics

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Spin Blockade in Capacitively Coupled Quantum Dots

We present transport measurements on a lateral double dot produced by combining local anodic oxidation and electron beam lithography. We investigate the tunability of our device and demonstrate, that we can switch between capacitive and tunnel coupling. In the regime of capacitive coupling we observe the phenomenon of spin blockade in a magnetic field and analyze the influence of capacitive interdot coupling on this effect.Comment: 4 pages, 3 figure

Pheasant Nesting and Vegetation Development in Dense Nesting Cover Established Under the South Dakota Pheasant Restoration Program

Pheasant (Phasianus colchicus) nest use of dense nesting cover (DNC) established under the Pheasant Restoration Program was evaluated in Beadle, Codington, Tripp, and Walworth Counties in South Dakota from 1978 to 1981. Nest densities and success in DNC plots were compared to those found in roadsides and privately owned alfalfa (Medicago sativa) fields, pastures, and small grain fields. Vegetation density and cover development were monitored on DNC plots. Nest densities were generally greatest in DNC plots followed by roadsides and alfalfa fields. Pastures and small grain fields contained the lowest nest densities. No relationship was detected between nest success and landuse. Overall nest success was 33.9%. Depredation by mammalian predators was the greatest cause for nest failure in all landuses and study areas. No relationship was detected between nest density or success and vegetation density in DNC plots. Species composition of DNC areas followed a successional pattern. Sweet clover (Melilotus spp.) tended to dominate DNC plots at age 2 years while alfalfa and finally wheatgrasses (Agropyron spp.) dominated DNC plots at age 5. Although DNC plots provided secure pheasant nesting habitat and harbored high nest densities, depredation of nests by mammalian predators appeared to offset major gains in nest success on these plots