Chromatic luminance,colorimetric purity,and optimal aperture‐color stimuli

Chromatic luminance (i.e., luminance of a monochromatic color) is the source of all luminance, since achromatic luminance arises only from mixing colors and their chromatic luminances. The ratio of chromatic luminance to total luminance (i.e., chromatic plus achromatic luminance) is known as colorimetric purity, and its measurement has long been problematic for nonspectral hues. Colorimetric purity (p_c) is a luminance metric in contrast to excitation purity, which is a chromaticity‐diagram metric approximating saturation. The CIE definition of p_c contains a fallacy. CIE defines maximum (1.0) p_c for spectral stimuli as monochromatic (i.e., optimal) stimuli, and as the line between spectrum ends for nonspectrals. However, this line has <0.003 lm/W according to CIE colorimetric data and is therefore effectively invisible. It only represents the limit of theoretically attainable colors, and is of no practical use in color reproduction or color appearance. Required is a locus giving optimal rather than invisible nonspectral stimuli. The problem is partly semantic. CIE wisely adopted the term colorimetric purity, rather than the original spectral luminance purity, to permit an equivalent metric for spectrals and nonspectrals, but the parameter of equivalence was never clear. Since 1 p_c denotes optimal aperture‐color stimuli for spectrals, arguably 1 p_c should denote optimal stimuli consistently for all stimuli. The problem reduces to calculating optimal aperture‐color stimuli (“optimal” in energy efficiency in color‐matching) for nonspectrals, shown to comprise 442 + 613 nm in all CIE illuminants. This remedy merely requires redefinition of 1 p_c for nonspectrals as the line 442–613 nm, and gives meaningful p_c values over the hue cycle allowing new research of chromatic luminance relations with color appearance. © 2007 Wiley Periodicals, Inc. Col Res Appl, 32, 469–476, 2007     

MANOVA method for analyzing repeated measures designs: An extensive primer.

Contends that tests in repeated-measures designs based on MANOVA are free of sphericity assumptions, and with modern computing software, MANOVA is straightforward to use, even for complex designs and nontraditional hypotheses. A general strategy for implementing MANOVA within statistical computing packages is presented. Regular (preplanned) tests and simultaneous (post hoc) tests are illustrated for a variety of designs and hypotheses. Optimal contrasts for unbalanced repeated measures designs are appended. (33 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Heat transfer and pressure drop in a new type of corrugated channels

An experimental investigation of heat transfer and pressure drop from a new type of corrugated channels is presented. The investigation has been carried out for Reynolds numbers in the range of $\text{800 <}\text{Re}\text{< 5000}$ for one corrugated and one smooth channel. It is found that the heat transfer from the corrugated channel is up to 3.5 times higher than for the smooth one. The pressure drop is however large (5 – 6 times the value of a smooth channel) and it is suggested that the corrugation height and length should be altered in order to balance the increases in heat transfer and pressure drop.     

Increased expression of platelet-derived growth factor receptor alpha and beta and vascular endothelial growth factor in the skin of patients with chronic venous insufficiency

Growth factors produced by a variety of cells act as signalling peptides through specific cell surface receptor pathways. Functions such as cell proliferation, migration and differentiation have been assigned to each of them. Here, we report alterations of platelet-derived growth factor receptor alpha (PDGFR-alpha) and beta (PDGFR-beta) and vascular endothelial growth factor (VEGF) expression patterns in the progressive clinical stages of chronic venous insufficiency (CVI). A total of 30 punch biopsies were taken from patients with CVI, and VEGF and PDGFR were detected by indirect immunofluorescence and immunoperoxidase techniques. PDGFR-alpha and PDGFR-beta expression was strongly increased in endothelial cells of capillaries, pericapillary cells and connective tissue cells in the stroma of the skin of venous eczema and venous leg ulcer patients, and to a smaller extend in the dermis of those with lipodermatosclerosis. VEGF staining showed a similar expression pattern in the progressive CVI stages. However, staining of vessels in particular might simply reflect binding of VEGF, secreted by keratinocytes or fibroblasts, to its receptors. Growth factor and receptor expression in specimens from telangiectases and reticular veins, and from pigmented areas, resembled that of normal skin. We conclude that PDGFR-alpha, PDGFR-beta and VEGF play an important role in mediating inflammation and epithelial hyperproliferation in venous eczema, inducing connective tissue sclerosis in lipodermatosclerosis, and causing the reduced reepithelialization tendency in venous ulcers. We speculate that endothelial proliferation with chronic venous hypertension might be mediated by these growth factors.     

Criteria for judging the admissibility of eyewitness testimony of long past events.

Court cases of recovered memories of childhood abuse, in which the victim's testimony may constitute the only evidence available, and a growing body of research demonstrating the inexactitude and suggestibility of autobiographical memory of long past events, are forcing courts and cognitive scientists to seek scientific, principled criteria for admissibility of such testimony. The authors use as examples 2 recent court cases. In the 1st case, a concussion produced total retrograde amnesia for an accident for a period of 3 years, and then, over a few months, the driver claimed his memory returned. In the 2nd, 2 adults reported to the police that they witnessed their sister's murder 35 years earlier, when they were 3 and 5 years old, respectively. The authors provide objective guidelines for courts to determine whether testimony about recovered or very-long-term memory for eyewitnessed events should be admissible. The principles outlined can be expanded easily to include eyewitness testimony in general. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Position and velocity coupling of postural sway to somatosensory drive

Light touch contact of a fingertip to a stationary surface provides orientation information that enhances control of upright stance. Slight changes in contact force at the fingertip lead to sensory cues about the direction of body sway, allowing attenuation of sway. In the present study, the coupling of postural sway to a moving contact surface was investigated in detail. Head, center of mass, and center of pressure displacement were measured as the contact surface moved rhythmically at 0.1, 0.2, 0.4, 0.6, and 0.8 Hz. Stimulus amplitude decreased with frequency to maintain peak velocity constant across frequency. Head and body sway were highly coherent with contact surface motion at all frequencies except 0.8 Hz, where a drop-off in coherence was observed. Mean frequency of head and body sway matched the driving frequency 相似文献   

Intact recognition of facial emotion in Parkinson's disease.

Although the basal ganglia have been shown to be critical for the expression of emotion in prosody and facial expressions, it is unclear whether they are also critical for recognition of emotions. Selective pathology of parts of the basal ganglia is a hallmark of individuals with Parkinson's disease, and such patients have been examined in several studies of emotion. We examined 18 patients with Parkinson's disease (11 men, 7 women) and 13 age-, education-, gender ratio-, and IQ-matched normal controls on their ability to recognize emotions signaled by facial expressions. Parkinson's patients performed entirely normally on a quantitative task of recognizing emotional facial expressions. The findings do not support the notion that the sectors of basal ganglia that are dysfunctional in Parkinson's disease are essential for recognizing emotion in facial expressions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)