Implication of the Yellow Pigment in Dichoptic Colour Mixing

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 122-122
Author(s):  
M L F de Mattiello ◽  
A R Biondini ◽  
H Salinas

Working with colours generated from the three primaries, we found earlier that blue made it difficult to obtain dichoptic mixtures, producing chromatostereopsis and alternation effects which disappeared with increasing eccentricity (1 deg 3 min) or decreasing intensity of the blue component. The unanswered question was: is it true that mixtures with a strong blue component can never be obtained centrally as some authors claim? Therefore, we returned to this subject, using the same methodology and analysing the role that the yellow pigment (YP) would play. First, the samples that previously produced the aforementioned effects were tested, confirming that chromatostereopsis stopped before the alternation. Immediately after that, identical samples were observed through low-density yellow filters that were superposed until both effects ceased. Since the density of the YP of the four participating observers had been previously measured, it was possible to calculate the necessary increase for each one of them, observing that the increment became smaller as the mixtures were displaced towards longer wavelengths. This behaviour indicates a possible function of YP: the attenuation of the blue cone signal to make it compatible with signal from the red and green cones. As the YP varies among observers, this might be the reason why some sources mention that these mixtures can be obtained. If this hypothesis is accepted, this should not be interpreted as a variation in the number of blue receptors through the macula, a variation not necessarily observed in physiology.


Author(s):  
P.J. Killingworth ◽  
M. Warren

Ultimate resolution in the scanning electron microscope is determined not only by the diameter of the incident electron beam, but by interaction of that beam with the specimen material. Generally, while minimum beam diameter diminishes with increasing voltage, due to the reduced effect of aberration component and magnetic interference, the excited volume within the sample increases with electron energy. Thus, for any given material and imaging signal, there is an optimum volt age to achieve best resolution.In the case of organic materials, which are in general of low density and electric ally non-conducting; and may in addition be susceptible to radiation and heat damage, the selection of correct operating parameters is extremely critical and is achiev ed by interative adjustment.



Author(s):  
L. Mulestagno ◽  
J.C. Holzer ◽  
P. Fraundorf

Due to the wealth of information, both analytical and structural that can be obtained from it TEM always has been a favorite tool for the analysis of process-induced defects in semiconductor wafers. The only major disadvantage has always been, that the volume under study in the TEM is relatively small, making it difficult to locate low density defects, and sample preparation is a somewhat lengthy procedure. This problem has been somewhat alleviated by the availability of efficient low angle milling.Using a PIPS® variable angle ion -mill, manufactured by Gatan, we have been consistently obtaining planar specimens with a high quality thin area in excess of 5 × 104 μm2 in about half an hour (milling time), which has made it possible to locate defects at lower densities, or, for defects of relatively high density, obtain information which is statistically more significant (table 1).



Author(s):  
Dean A. Handley ◽  
Cynthia M. Arbeeny ◽  
Larry D. Witte

Low density lipoproteins (LDL) are the major cholesterol carrying particles in the blood. Using cultured cells, it has been shown that LDL particles interact with specific surface receptors and are internalized via a coated pit-coated vesicle pathway for lysosomal catabolism. This (Pathway has been visualized using LDL labeled to ferritin or colloidal gold. It is now recognized that certain lysomotropic agents, such as chloroquine, inhibit lysosomal enzymes that degrade protein and cholesterol esters. By interrupting cholesterol ester hydrolysis, chloroquine treatment results in lysosomal accumulation of cholesterol esters from internalized LDL. Using LDL conjugated to colloidal gold, we have examined the ultrastructural effects of chloroquine on lipoprotein uptake by normal cultured fibroblasts.



Author(s):  
Ian M. Anderson

B2-ordered iron aluminide intermetallic alloys exhibit a combination of attractive properties such as low density and good corrosion resistance. However, the practical applications of these alloys are limited by their poor fracture toughness and low room temperature ductility. One current strategy for overcoming these undesirable properties is to attempt to modify the basic chemistry of the materials with alloying additions. These changes in the chemistry of the material cannot be fully understood without a knowledge of the site-distribution of the alloying elements. In this paper, the site-distributions of a series of 3d-transition metal alloying additions in B2-ordered iron aluminides are studied with ALCHEMI.A series of seven alloys of stoichiometry Fe50AL45Me5, with Me = {Ti, V, Cr, Mn, Co, Ni, Cu}, were prepared with identical heating cycles. Microalloying additions of 0.2% B and 0.1% Zr were also incorporated to strengthen the grain boundaries, but these alloying additions have little influence on the matrix chemistry and are incidental to this study.



Author(s):  
C. W. Price ◽  
E. F. Lindsey ◽  
R. M. Franks ◽  
M. A. Lane

Diamond-point turning is an efficient technique for machining low-density polystyrene foam, and the surface finish can be substantially improved by grinding. However, both diamond-point turning and grinding tend to tear and fracture cell walls and leave asperities formed by agglomerations of fragmented cell walls. Vibratoming is proving to be an excellent technique to form planar surfaces in polystyrene, and the machining characteristics of vibratoming and diamond-point turning are compared.Our work has demonstrated that proper evaluation of surface structures in low density polystyrene foam requires stereoscopic examinations; tilts of + and − 3 1/2 degrees were used for the stereo pairs. Coating does not seriously distort low-density polystyrene foam. Therefore, the specimens were gold-palladium coated and examined in a Hitachi S-800 FESEM at 5 kV.





1996 ◽  
Vol 8 (1) ◽  
pp. 177-188 ◽  
Author(s):  
N. Qaddoumi ◽  
S. Ganchev ◽  
R. Zoughi
Keyword(s):  


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