Bias in judgement: Comparing individuals and groups

The relative susceptibility of individuals and groups to systematic judgmental biases is considered. An overview of the relevant empirical literature reveals no clear or general pattern. However, a theoretical analysis employing J. H. Davis's (1973) social decision scheme (SDS) model reveals that the relative magnitude of individual and group bias depends upon several factors, including group size, initial individual judgment, the magnitude of bias among individuals, the type of bias, and most of all, the group-judgment process. It is concluded that there can be no simple answer to the question, "Which are more biased, individuals or groups?," but the SDS model offers a framework for specifying some of the conditions under which individuals are both more and less biased than groups

Self-consistent calculation of electric potentials in Hall devices

Using a first-principles classical many-body simulation of a Hall bar, we study the necessary conditions for the formation of the Hall potential: (i) Ohmic contacts with metallic reservoirs, (ii) electron-electron interactions, and (iii) confinement to a finite system. By propagating thousands of interacting electrons over million time-steps we capture the build-up of the self-consistent potential, which resembles results obtained by conformal-mapping methods. As shown by a microscopic model of the current injection, the Hall effect is linked to specific boundary conditions at the particle reservoirs.Comment: 6 pages, 7 figure

Theory of the quantum Hall effect in graphene

We study the quantum Hall effect (QHE) in graphene based on the current injection model. In our model, the presence of disorder, the edge-state picture, extended states and localized states, which are believed to be indispensable ingredients in describing the QHE, do not play an important role. Instead the boundary conditions during the injection into the graphene sheet, which are enforced by the presence of the Ohmic contacts, determine the current-voltage characteristics.Comment: 4 pages, 3 figures, rewritten, role of contacts for boundary conditions in small device

Leafy Spurge Biological Control Using Black Dot Flea Beetles and Deleterious Rhizobacteria: Final Report Submitted to South Dakota Department of Agriculture Weed and Pest Control

Size of leafy spurge (Euphorbia esula L) roots and their location in the soil profile are important factors relating to survival offirst-instar black dot flea beetle (Aphthona nigriscutis Foudras) larvae. First-instar larvae must find leafy spurge roots between 1 to 4 mm diam in the first 2 days after hatching from eggs for survival. In field studies, we ddermined that most flea beetle larvae reside within 7.6 em ofthe soil surface. Their location in the upper areas ofthe soil profile allows accessibility to desirable size roots, however the larvae are more susceptible to freezing temperatures in this region. Overall, there were fewer black dot flea beetle larvae in the soil at the Pollock site in 1997 compared to 1995 and 1996. In 1997, harsh winter weather conditions may have resulted in high mortality of larvae