Efficient Reflectance and Visibility Approximations for Environment Map Rendering

We present a technique for approximating isotropic BRDFs and precomputed self-occlusion that enables accurate and efficient prefiltered environment map rendering. Our approach uses a nonlinear approximation of the BRDF as a weighted sum of isotropic Gaussian functions. Our representation requires a minimal amount of storage, can accurately represent BRDFs of arbitrary sharpness, and is above all, efficient to render. We precompute visibility due to self-occlusion and store a low-frequency approximation suitable for glossy reflections. We demonstrate our method by fitting our representation to measured BRDF data, yielding high visual quality at real-time frame rates.     

Mixed-Cation Oxide Powders via Resin Intermediates Derived from a Water-Soluble Polymer

Submicrometer powders of complex oxides were prepared via resin intermediates based on a starch type of organic precursor. A commercially available water-soluble starch derivative was (for the first time) used as the organic base for solution synthesis of ceramic powders. Calcination of the charred, fluffy, amorphous resins at a temperature below 600°C for 4 h yielded perovskite powders of Sr-doped LaMnO₃ and Sr-doped La(Fe,Co)O₃. Sr-doped LaCrO₃ needed to be calcined above 750°C to ensure phase purity and to remove organic residue. Due to the low cost of starch derivatives, the process has the potential of being more economical than the commonly used Pechini's type process, which utilizes citric acid and ethylene glycol.     

The modern face of prejudice and structural features that moderate the effect of cooperation on affect

Facial muscle activity and self-reports were examined for racial bias in 3 studies. In the first 2 experiments, While participants imagined cooperating with a Black or White partner. Experiment 1 manipulated reward structure in the context of cooperating with a deficient partner. Experiment 2 manipulated partner deficiency and willingness to expend compensatory effort. On both facial EMG and self-report measures, joint rewards produced more negative affect than independent rewards. However, all partners were liked more when they were willing to try to compensate for their deficits. In addition, more liking was reported for Black partners, but EMG activity indicated bias against Blacks. Experiment 3 investigated individual differences in prejudice. Again, a greater preference for Blacks than Whites occurred on self-report measures, but in their facial muscle activity, high-prejudiced participants exhibited bias against Blacks.     

Conifers and commemoration — the politics and protocol of planting

This study examines the symbolic role of trees, shrubs and flowers on 20th century battle grounds and military cemeteries. By focusing on the imagery of commemoration and on the power of horticultural symbols the paper explores the emergence of an iconography during wartime and its perpetuation in ritualized peacetime landscapes. The paper makes specific reference to the Western Front in France and Belgium, and to the consecrated ground of the Dardanelles peninsula — a commemorative terrain that is being altered by Turkish planting and memorial schemes that are bringing into sharp focus the problems of maintaining Christian burial grounds in perpetuity across the globe. The paper concludes by asking whether tree planting may have replaced memorial building in the rhetoric and culture of commemoration.     

Reading and skimming from computer screens and books: the paperless office revisited?

Past research has demonstrated that reading efficiency is lower from the standard computer displays of the 1980s than from paper. In the present experiments, subjects read or skimmed stories, sometimes from a high-quality CRT (cathode ray tube) and sometimes from a book. Skimming was 41% slower from the CRTs than from the book. Possible reasons for this finding are discussed. Reading speed and comprehension were equivalent for the high-quality CRTs and the book. The paperless office may be imminent after all.     

Influence of cage design on precision of tube-trap bioassay for attractants of the onion fly,Delia antiqua

Responses of onion flies,Delia antiqua, to known attractants were measured in the laboratory with a novel tube-trap bioassay. The relative numbers of flies caught in tube traps baited with enzymatic yeast hydrolysate, brewer's yeast, andn-dipropyl disulfide were similar to those obtained previously with cone traps in the field. Changing the shape of the bioassay cage from a cuboid to a cylinder decreased the experimental error obtained from analysis of variance, as did rotating the floor of the circular cage. This bioassay should be useful in evaluating attractants for other insects that orient along the substrate.Diptera: Anthomyiidae.Paper No. 11327 of the Michigan State University Agricultural Experiment Station. Received for publication June 8, 1984.