The right view from the wrong location: depth perception in stereoscopic multi-user virtual environments

Stereoscopic depth cues improve depth perception and increase immersion within virtual environments (VEs). However, improper display of these cues can distort perceived distances and directions. Consider a multi-user VE, where all users view identical stereoscopic images regardless of physical location. In this scenario, cues are typically customized for one "leader" equipped with a head-tracking device. This user stands at the center of projection (CoP) and all other users ("followers") view the scene from other locations and receive improper depth cues. This paper examines perceived depth distortion when viewing stereoscopic VEs from follower perspectives and the impact of these distortions on collaborative spatial judgments. Pairs of participants made collaborative depth judgments of virtual shapes viewed from the CoP or after displacement forward or backward. Forward and backward displacement caused perceived depth compression and expansion, respectively, with greater compression than expansion. Furthermore, distortion was less than predicted by a ray-intersection model of stereo geometry. Collaboration times were significantly longer when participants stood at different locations compared to the same location, and increased with greater perceived depth discrepancy between the two viewing locations. These findings advance our understanding of spatial distortions in multi-user VEs, and suggest a strategy for reducing distortion.     

Oxidative dimerisation of propene to 1,5-hexadiene on Bi-Zn-O catalysts

The oxidative dimerisation of propene to 1,5-hexadiene has been investigated on Bi-Zn-O catalysts. The Bi₄₈ZnO₇₃ phase, observed in the catalysts calcined at 700 ° C is an active and selective catalyst for the formation of 1,5-hexadiene. The best catalytic performance (1,5-hexadiene selectivity 64%) has been obtained at 525 ° C, with a propene to oxygen ratio of 26, on a catalyst formed by Bi₄₈ZnO₇₃ with a small excess of ZnO.     

Fiber optic sensing for ultrasonic NDE

An innovative approach to nondestructive evaluation (NDE) using noncontacting optical sensors has demonstrated. In this effort a single mode optical fiber interferometer (OFI) was used to sense the presence and form of Rayleigh waves traveling along the surface of a steel test bar at a velocity of nearly 3mm/µs. Acousto-optic time-domain data was successfully used to detect the presence and locate the position of a test flaw (a machined slot) in the bar, and spectrum analysis was used to estimate its geometry and size. This approach has many potential applications in the ultrasonic evaluation of real flaws in structures with complex geometries. Coupled with the authors' earlier work demonstrating the feasibility of generating acoustic waves in metals using laser light pulses transmitted through the fiber optic probes, this latest achievement points to the development of a fully noncontacting, fiber optic based thermal-acousto-photonic (TAP) NDE system, with potential applications to the reliability testing of many important structures where composition, scale, geometry, or restricted access preclude the use of conventional NDE techniques.     

Interspecies Behavioral Variability of Medaka Fish Assessed by Comparative Phenomics

Recently, medaka has been used as a model organism in various research fields. However, even though it possesses several advantages over zebrafish, fewer studies were done in medaka compared to zebrafish, especially with regard to its behavior. Thus, to provide more information regarding its behavior and to demonstrate the behavioral differences between several species of medaka, we compared the behavioral performance and biomarker expression in the brain between four medaka fishes, Oryzias latipes, Oryzias dancena, Oryzias woworae, and Oryzias sinensis. We found that each medaka species explicitly exhibited different behaviors to each other, which might be related to the different basal levels of several biomarkers. Furthermore, by phenomics and genomic-based clustering, the differences between these medaka fishes were further investigated. Here, the phenomic-based clustering was based on the behavior results, while the genomic-based clustering was based on the sequence of the nd2 gene. As we expected, both clusterings showed some resemblances to each other in terms of the interspecies relationship between medaka and zebrafish. However, this similarity was not displayed by both clusterings in the medaka interspecies comparisons. Therefore, these results suggest a re-interpretation of several prior studies in comparative biology. We hope that these results contribute to the growing database of medaka fish phenotypes and provide one of the foundations for future phenomics studies of medaka fish.     

Large-scale in vivo synthesis of the carbohydrate moieties of gangliosides GM1 and GM2 by metabolically engineered Escherichia coli

Two metabolically engineered Escherichia coli strains have been constructed to produce the carbohydrate moieties of gangliosides GM2 (GalNAcbeta-4(NeuAcalpha-3)Galbeta-4Glc; Gal = galactose, Glc = glucose, Ac = acetyl) and GM1 (Galbeta-3GalNAcbeta-4(NeuAcalpha-3)Galbeta-4Glc. The GM2 oligosaccharide-producing strain TA02 was devoid of both beta-galactosidase and sialic acid aldolase activities and overexpressed the genes for CMP-NeuAc synthase (CMP = cytidine monophosphate), alpha-2,3-sialyltransferase, UDP-GlcNAc (UDP = uridine diphosphate) C4 epimerase, and beta-1,4-GalNAc transferase. When this strain was cultivated on glycerol, exogenously added lactose and sialic acid were shown to be actively internalized into the cytoplasm and converted into GM2 oligosaccharide. The in vivo synthesis of GM1 oligosaccharide was achieved by taking a similar approach but using strain TA05, which additionally overexpressed the gene for beta-1,3-galactosyltransferase. In high-cell-density cultures, the production yields for the GM2 and GM1 oligosaccharides were 1.25 g L(-1) and 0.89 g L(-1), respectively.     

Structural study of hexane-soluble products from hydroliquefaction of three Yallourn brown coal lithotypes over molten salt catalysts

The hexane-soluble fractions of hydroliquefied products from three Yallourn brown coal lithotypes have been separated into five fractions by combined silica-alumina packed column chromatography. Analyses of various fractions by g.c.-m.s. permitted the identification of ≈50 components in the saturate fraction and 40 components in the diaromatic fraction, together with 30 components in the monoaromatics. The components identified were quite similar among hexane-soluble portions of all three lithotypes. A marked predominance of even carbon number alkane (C₂₃-C₂₉) was observed in the hydrocarbon fractions from pale lithotype over $\text{ZnCl}{}_2\text{KCl}$, and medium light lithotype over both pure ZnCl₂ and $\text{ZnCl}{}_2\text{KCl}$. However, medium dark lithotype over both melt catalysts produced a saturate fraction with an odd carbon number(C₂₂-C₂₈) preference. Based on spectral methods, Soxhlet extracts obtained from untreated lithotypes (hexane and benzene solubles) were characterized as complex mixtures of higher molecular weight(300–1000) aliphatic hydrocarbons, which were supposed to be a precursor of the saturates produced from the corresponding lithotype in the catalytic hydroliquefaction.     

Activities of MFI-Supported Rhenium Catalysts for the Aromatization of Methane: Effect of Cationic Form of the Inorganic Carrier

MFI type inorganic carrier was used in two different cationic forms, hydrogen and calcium respectively. MFI-supported molybdenum and rhenium catalysts were prepared. The activities of the catalysts were compared for the aromatization reaction of methane. Higher activity values were attained with the catalysts supported on HZSM-5. Aromatics were also observed with the catalysts supported on CaZSM-5, despite their deficiency in acid sites. Highly dispersed rhenium is expected to be formed with the use of the inorganic carrier in calcium form. On the other hand, lower reaction rates were observed with rhenium supported on CaZSM-5, in spite of the improved dispersion of the active rhenium species on this catalyst. This was interpreted in terms of the critical role of the acid sites in the conversion of methane to aromatics, compared to the improved dispersion of the active metal.     

Plasma modification of cellulose derivatives as biomaterials

A film of cellulose acetate was submitted to a cold plasma of tetrafluoromethane or of sulfur hexafluoride. The interactions of these cold plasmas and cellulose acetate lead to a material whose surface has been modified by fluorination. Comparison of CF₄ or SF₆ plasma treatment shows that fluorine atoms provided by each kind of plasma induce degradation and grafting of fluorocarbon radicals on the surface. As a consequence, the surface energy decreases and offers the possibility of a better response of plasma-modified cellulose derivatives used as biomaterials (e.g. hemodialysis membrane).     

—Review Paper—Current State-Of-The-Art Measurements Of Ozone In The Gas Phase And In Solution

This paper is a critical review and summary of the analytical procedures currently used by operating water utilities to control ozone treatment processes, considering disinfection as well as the many oxidative applications of ozone in water treatment applications. The role of common interferences in the various methods is described.

In operating U S., Canadian, European, and Japanese water treatment plants currently employing ozone as a primary disinfectant, ozone nearly always is followed by the addition of small quantities of chlorine, chlorine dioxide, or chloramine to provide the residual in the distribution system and to act as a secondary disinfectant. Clearly, the analytical procedures used must distinguish between the various species. This review critically presents these various factors and their implication with respect to “true values” of ozone determined under widely varying conditions.