Hyperspace geography: Visualizing fitness landscapes beyond 4D

Human perception is finely tuned to extract structure about the 4D world of time and space as well as properties such as color and texture. Developing intuitions about spatial structure beyond 4D requires exploiting other perceptual and cognitive abilities. One of the most natural ways to explore complex spaces is for a user to actively navigate through them, using local explorations and global summaries to develop intuitions about structure, and then testing the developing ideas by further exploration. This article provides a brief overview of a technique for visualizing surfaces defined over moderate-dimensional binary spaces, by recursively unfolding them onto a 2D hypergraph. We briefly summarize the uses of a freely available Web-based visualization tool, Hyperspace Graph Paper (HSGP), for exploring fitness landscapes and search algorithms in evolutionary computation. HSGP provides a way for a user to actively explore a landscape, from simple tasks such as mapping the neighborhood structure of different points, to seeing global properties such as the size and distribution of basins of attraction or how different search algorithms interact with landscape structure. It has been most useful for exploring recursive and repetitive landscapes, and its strength is that it allows intuitions to be developed through active navigation by the user, and exploits the visual system's ability to detect pattern and texture. The technique is most effective when applied to continuous functions over Boolean variables using 4 to 16 dimensions.

Negative second virial coefficients as predictors of protein crystal growth: Evidence from sedimentation equilibrium studies that refutes the designation of those light scattering parameters as osmotic virial coefficients

The effects of ammonium sulphate concentration on the osmotic second virial coefficient (B-AA/M-A) for equine serum albumin (pH 5.6, 20 degrees C) have been examined by sedimentation equilibrium. After an initial steep decrease with increasing ammonium sulphate concentration, B-AA/M-A assumes an essentially concentration-independent magnitude of 8-9 ml/g. Such behaviour conforms with the statistical-mechanical prediction that a sufficient increase in ionic strength should effectively eliminate the contributions of charge interactions to B-AA/M-A but have no effect on the covolume contribution (8.4 ml/g for serum albumin). A similar situation is shown to apply to published sedimentation equilibrium data for lysozyme (pH 4.5). Although termed osmotic second virial coefficients and designated as such (B-22), the negative values obtained in published light scattering studies of both systems have been described incorrectly because of the concomitant inclusion of the protein-salt contribution to thermodynamic nonideality of the protein. Those negative values are still valid predictors of conditions conducive to crystal growth inasmuch as they do reflect situations in which there is net attraction between protein molecules. However, the source of attraction responsible for the negative virial coefficient stems from the protein-salt rather than the protein-protein contribution, which is necessarily positive. (c) 2005 Elsevier B.V. All rights reserved.

Reactions to positive deviance: Social identity and attribution dimensions

This research examines whether evaluations of positive deviates (i.e. high achieving group members) are influenced by the attributions they make for their performance. We argue that ingroup positive deviates who make group attributions help enhance the ingroup's image and thus attract favorable evaluations. In Experiment 1, ingroup positive deviates who made group attributions were generally evaluated more favorably than ingroup positive deviates who made individual attributions. There was also evidence that the positive deviates' attribution style influenced group and self-evaluations. Evaluations of outgroup positive deviates were not influenced by their attribution style. In Experiment 2, an ingroup positive deviate who was successful and attributed that success to the group was upgraded relative to an ingroup positive deviate who made individual attributions. Group evaluations were also higher when the positive deviate made group attributions. This pattern did not emerge when the positive deviate failed. The results are discussed from a social identity perspective.

Twin study of adolescent genetic susceptibility to mosquito bites using ordinal and comparative rating data

Ordinal and comparative rating measures of mosquito attraction and mosquito bite frequency and symptoms were administered in a self-report questionnaire format to a sample of 197 monozygotic and 326 dizygotic Australian adolescent twin pairs at age 12 between 1992 and 1999, in order to investigate the environmental and possibly genetic determinants of variation between individuals. Repeat measures were obtained from the twin pairs at age 14. Ordinal variable measures, although providing some support for genetic effects on mosquito susceptibility, were affected by low repeatability. However, analysis of a comparative rating variable compared with your twin, who is bitten by mosquitoes more often? indicated a strong genetic influence on frequency of being bitten by mosquitoes, with no significant differences observed between males and females. Comparative rating questionnaire items are a potentially valuable tool for complementing and improving the results obtained from more conventional absolute measures. (C) 2000 Wiley-Liss, Inc.

Workplace diversity: The moderating role of work context on the relationship between surface and deep level diversity and group functioning

This research examines the relationship between perceived group diversity and group conflict, and the moderating role of team context. Currentiy, diversity research predominantly focuses on surface and job-related dimensions, largely to the neglect of deep-level diversity (in terms of values, attitude and beliefs). First, this research hjfpothesised that all three dimensions of diversity would be positively related to group conflict, with deep-level diversity the strongest predictor of task. conflict. Second, it was hypothesised that team context would moderate the relationship between deep-level diversity and group conflict. Team context refers to the extent to which the work performed (1) has high consequences (in terms of health and well being for team members and others); (2) is relatively isolating, (3) requires a high reliance upon team members; (4) is volatile; and (5) interpersonal attraction and mutual helpfulness is essential. Two studies were conducted. The first study employed 44 part-time employees across a range of occupations, and the second study employed 66 full-time employees from a mining company in Australia. A series of hierarchical multiple regressions and moderated multiple regressions confirmed both hypotheses. Practical implications and future research directions are discussed.