Color recognition

Dalton stayed in Manchester for the rest of his fife, and it was there that he did most of his important work, the results of which were published in the Memoirs of the Manchester Literary and Philosophical Society (MLPS). His first scientific paper, published by the MLPS in 1798, described his red-green color blindness. Dalton is said to have purchased for his mother a pair of what he thought were dull-colored stockings—Quakers did not wear bright colors—which she could not wear because they were scarlet. This misadventure motivated Dalton to investigate his color recognition deficiency. He was the first to describe red-green color blindness, sometimes known as Daltonism. 

The age of computer technology is here. The software packages currently available for computer color matching have tremendously improved over the past few years and will continue to improve dramatically as current human and computer research continues to search for those color recognition patterns that more closely mimic the human eye and brain processes. So far, the eye still has the lead, but for how much longer ... 

Hussain, S.G. and J.B. Arens, etal. (1991). Effect of light sources on highway sign color recognition. Applied Ergonomics 22 (2) 27-34. 

These views seem to be well applicable to the pyrotechnic color recognition and identifleation problems. Red, green, and yellow are the... 

In a more limited way, a problem exists in the proper naming of colors, and perhaps also in the bias of some observers with otherwise normal color recognition (such as the writer) toward the color yellow, whereby the slightest admixture of yellow to blue, especially in light shades, makes the person call this color green rather than blue. ... 

In contrast, the range of color recognition spans a much wider angle of +/- 60° horizontally and +30°/-45° vertically. Coloured elements placed in this visible field are discernable without loss of focus so it is possible to focus on the traffic and at the same time to recognize the coloured information on the screen. And humans visual perception is able to recognize colours within only 200-300ms. 

Participants were shown the color combinations of five popular brands of laundry detergent. They were then asked to identify the brand based on color recognition alone. Bottle shape and packaging were excluded from the study by cutting out pieces of the... 

Figure 7.7 Color codes for the recognition patterns at the edges of the base pairs in the major (a) and minor (b) grooves of B-DNA. Hydrogen-bond acceptors are red hydrogen-bond donors are blue. The methyl group of thymine is yellow, while the corresponding H atom of cytosine is white.

Figure 7.8 Sequence-specific recognition sites in the major groove of DNA for three restriction enzymes—Eco RI, Bal I, and Sma I. The DNA sequences that are recognized by these enzymes ate represented by tbe color code defined in Figure 7.7.

Only a rather limited number of base pairs is needed to provide unique and discriminatory recognition sites in the major groove. This is illustrated in Figure 7.8, which gives the color codes for the hexanucleotide recognition sites of three different restriction enzymes—Eco Rl, Bal 1, and Sma 1. It is clear that these patterns are quite different, and each can be uniquely recognized by specific protein-DNA interactions. 

Figure 9.12 Schematic diagram of the structure of the heterodimeric yeast transcription factor Mat a2-Mat al bound to DNA. Both Mat o2 and Mat al are homeodomains containing the helix-turn-helix motif. The first helix in this motif is colored blue and the second, the recognition helix, is red. (a) The assumed structure of the Mat al homeodomain in the absence of DNA, based on Its sequence similarity to other homeodomains of known structure, (b) The structure of the Mat o2 homeodomain. The C-terminal tail (dotted) is flexible in the monomer and has no defined structure, (c) The structure of the Mat a 1-Mat a2-DNA complex. The C-terminal domain of Mat a2 (yellow) folds into an a helix (4) in the complex and interacts with the first two helices of Mat a2, to form a heterodimer that binds to DNA. (Adapted from B.J. Andrews and M.S. Donoviel, Science 270 251-253, 1995.)...

Note In the case of HPTLC plates the detection limit for the visual recognition of the violet = 530 nm) colored chromatogram zones was 20 ng per chromatogram zone. With the exception of the two tetrahydrosteroids the cor-ticosteriods could be detected on TLC plates with fluorescent indicators by reason of fluorescence quenching (Fig. 1 A). Figure 2 illustrates the absorption scans of the separations illustrated in Figures 1A and 1B. 

Szente, L. et al.. Stabilization and solubilization of lipophilic natural colorants with cyclodextrins, J. Inclusion Phen. Mol. Recognition Chem., 32, 91, 1998. 

High performance spectroscopic methods, like FT-IR and NIR spectrometry and Raman spectroscopy are widely applied to identify non-destructively the specific fingerprint of an extract or check the stability of pure molecules or mixtures by the recognition of different functional groups. Generally, the infrared techniques are more frequently applied in food colorant analysis, as recently reviewed. Mass spectrometry is used as well, either coupled to HPLC for the detection of separated molecules or for the identification of a fingerprint based on fragmentation patterns. ... 

Terrick T.D., Mumme R.L. and Burghardt G.M. (1995). Aposematic coloration enchances chemosensory recognition of noxious prey in the garter snake Thamnophis radix. Anim Behav 49, 857-866. 

Tea oxidation is generally referred to as fermentation because of the erroneous early conception of black tea production as a microbial process.66 Not until 1901 was there recognition of the process as one dependent on an enzymically catalyzed oxidation.67 This step and further reactions result in the conversion of the colorless flavanols to a complex mixture of orange-yellow to red-brown substances and an increase in the amount and variety of volatile compounds. Extract of oxidized leaf is amber-colored and less astringent than the light yellow-green extract of fresh leaf and the flavor profile is considerably more complex. 

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