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Concept: Primary color


Is there a link between the color of a taxi and how many accidents it has? An analysis of 36 mo of detailed taxi, driver, and accident data (comprising millions of data points) from the largest taxi company in Singapore suggests that there is an explicit link. Yellow taxis had 6.1 fewer accidents per 1,000 taxis per month than blue taxis, a 9% reduction in accident probability. We rule out driver difference as an explanatory variable and empirically show that because yellow taxis are more noticeable than blue taxis-especially when in front of another vehicle, and in street lighting-other drivers can better avoid hitting them, directly reducing the accident rate. This finding can play a significant role when choosing colors for public transportation and may save lives as well as millions of dollars.

Concepts: Color wheel, Green, Indigo, Complementary color, Primary color, Taxicab, Yellow, Color


A basic premise of the recently proffered color-in-context model is that the influence of color on psychological functioning varies as a function of the psychological context in which color is perceived. Some research has examined the appetitive and aversive implications of viewing the color red in romance- and achievement-relevant contexts, respectively, but in all existing empirical work approach and avoidance behavior has been studied in separate tasks and separate experiments. Research is needed to directly test whether red influences the same behavior differently depending entirely on psychological context.

Concepts: RGB color model, Visible spectrum, Green, Science, Primary color, Color, Red, Psychology


Electrochromic polymers (ECPs) have been shown to be synthetically tunable, producing a full palette of vibrantly colored to highly transmissive polymers. The development of these colored-to-transmissive ECPs employed synthetic design strategies for broad color targeting; however, due to the subtleties of color perception and the intricacies of polymer structure and color relationships, fine color control is difficult. In contrast, color mixing is a well-established practice in the printing industry. We have identified three colored-to-transmissive switching electrochromic polymers, referred to as ECP-Cyan (ECP-C), ECP-Magenta (ECP-M), and ECP-Yellow (ECP-Y), which, via the co-processing of multicomponent ECP mixtures, follow the CMY color mixing model. The presented work qualitatively assesses the thin film characteristics of solution co-processed ECP mixtures. To quantitatively determine the predictability of the color properties of ECP mixtures, we estimated mass extinction coefficients (εmass) from solution spectra of the CMY ECPs and compared the estimated and experimentally observed color values of blends via a calculated color difference (ΔEab). The values of ΔEab range from 8 to 26 across all mixture compositions, with an average value of 15, representing a reasonable degree of agreement between predicted and observed color values. We demonstrate here the ability to co-process ECP mixtures into vibrantly colored, visually continuous films and the ability to estimate the color properties produced in these mixed ECP films.

Concepts: Polymer, Printing, Mix, RGB color model, Primary color, Color space, Color, Color theory


Gold nanorods exhibit rich colours owing to the nearly linear dependence of the longitudinal plasmon resonance wavelength on the length-to-diameter aspect ratio. This property of Au nanorods has been utilized in this work for dyeing fabrics. Au nanorods of different aspect ratios were deposited on both cotton and silk fabrics by immersing them in Au nanorod solutions. The coating of Au nanorods makes the fabrics exhibit a broad range of colours varying from brownish red through green to purplish red, which are essentially determined by the longitudinal plasmon wavelength of the deposited Au nanorods. The colorimetric values of the coated fabrics were carefully measured for examining the colouring effects. The nanorod-coated cotton fabrics were found to be commercially acceptable in washing fastness to laundering tests and colour fastness to dry cleaning tests. Moreover, the nanorod-coated cotton and silk fabrics show significant improvements on both UV-protection and antibacterial functions. Our study therefore points out a promising approach for the use of noble metal nanocrystals as dyeing materials for textile applications on the basis of their inherent localized plasmon resonance properties.

Concepts: Primary color, Tertiary color, Silk, Color, Ratios, Textile, Ratio, Aspect ratio


ETHNOPHARMACOLOGICAL RELEVANCE: Red edible bird’s nests are regarded as of higher beneficial value for health and hence fetch a higher price than the white ones. Their red colour remains a myth. AIM OF THE STUDY: To determine if white edible bird’s nests can turn red by vapours generated from sodium nitrite in acidic conditions and by vapours from ‘bird soil’. MATERIALS AND METHODS: White edible bird’s nests were exposed to vapours from sodium nitrite dissolved in 2% HCl or from ‘bird soil’ in hot and humid conditions. CONCLUSIONS: Vapours from sodium nitrite dissolved in 2% HCl or from ‘bird soil’ containing guano droppings from swiftlet houses were able to turn white edible bird’s nests red. The reddening agent in ‘bird soil’ was water-soluble and heat-stable. The red colour of edible bird’s nests is likely caused by the environmental factors in cave interiors and swiftlet houses.

Concepts: Guano, Manure, Primary color, Ammonia, Green, White, Color, Red


Previous research has demonstrated that colors of lighting can modulate participants' motivation to consume the food placed under the lighting. This study was designed to determine whether the colors of lighting can affect the amount of food consumed, in addition to sensory perception of the food. The influence of lighting color was also compared between men and women. One-hundred twelve participants (62 men and 50 women) were asked to consume a breakfast meal (omelets and mini-pancakes) under one of three different lighting colors: white, yellow, and blue. During the test, hedonic impression of the food’s appearance, willingness to eat, overall flavor intensity and overall impression of the food, and meal size (i.e., the amount of food consumed) were measured. Blue lighting decreased the hedonic impression of the food’s appearance, but not the willingness to eat, compared to yellow and white lighting conditions. The blue lighting significantly decreased the amount consumed in men, but not in women, compared to yellow and white lighting conditions. Overall flavor intensity and overall impression of the food were not significantly different among the three lighting colors. In conclusion, this study provides empirical evidence that the color of lighting can modulate the meal size. In particular, blue lighting can decrease the amount of food eaten in men without reducing their acceptability of the food.

Concepts: Complementary color, Yellow, Primary color, White, International Commission on Illumination, Qualia, Color, Light


To fold or not to fold? It is shown that attached sugars play a defining role in the conformations adopted by a pair of novel SAA-derived foldamers in water and that these differences are reflected in the contrasting interactions of these glycofoldamers with various biological targets. C green, O red, N blue, H gray; green oval=mannose.

Concepts: Cyan, Primary color, Natural environment, Ecology, Life, Green, Red, Aristotle


A robust synthesis of silver nanoparticles (AgNPs) using the peel extract of Punica granatum is reported in this article. The formation of AgNPs was confirmed by the appearance of brownish yellow color and the Surface Plasmon Resonance (SPR) peak at 432nm. The biogenic AgNPs were found to have the size approximately 30nm with distorted spherical shape. The high negative zeta potential values of AgNPs revealed their high stability which could be attributed to the capping of AgNPs by the phytoconstituents of the Punica granatum peel. The biogenic AgNPs were also found to function as an effective green catalyst in the reduction of anthropogenic pollutant viz., 4-nitrophenol (4-NP) by solid sodium borohydride, which was evident from the instantaneous color change of bright yellow (400nm) to colorless (294nm) solution, after the addition of AgNPs. The catalytic action of biogenic AgNPs in the reduction of 4-NP could be explained on the basis of Langmuir-Hinshelwood model.

Concepts: Green, Color wheel, Nanotechnology, White, Pomegranate, Color, Primary color, Surface plasmon resonance


Color vision in birds is mediated by four types of cone photoreceptors whose maximal sensitivities (λmax) are evenly spaced across the light spectrum. In the course of avian evolution, the λmax of the most shortwave-sensitive cone, SWS1, has switched between violet (λmax > 400 nm) and ultraviolet (λmax.

Concepts: Primary color, Wavelength, Visible spectrum, Color, Color vision, Color blindness, Cone cell, Photoreceptor cell


Despite lacking genetic evidence of a third cone opsin in the retina of any Australian marsupial, most species tested so far appear to be trichromatic. In the light of this, we have re-examined colour vision of the tammar wallaby which had previously been identified as a dichromat. Three different psychophysical tests, based on an operant conditioning paradigm, were used to confirm that colour perception in the wallaby can be predicted and conclusively explained by the existence of only two cone types. Firstly, colour-mixing experiments revealed a Confusion Point between the three primary colours of a LCD monitor that can be predicted by the cone excitation ratio of the short- and middle-wavelength sensitive cones. Secondly, the wavelength discrimination ability in the wallaby, when tested with monochromatic stimuli, was found to be limited to a narrow range between 440 nm and 500 nm. Lastly, an experiment designed to test the wallaby’s ability to discriminate monochromatic lights from a white light provided clear evidence for a Neutral Point around 485 nm where discrimination consistently failed. Relative colour discrimination seemed clearly preferred but it was possible to train a wallaby to perform absolute colour discriminations. The results confirm the tammar wallaby as a dichromat, and so far the only behaviourally confirmed dichromat among the Australian marsupials.

Concepts: Visible spectrum, Marsupial, Primary color, Photoreceptor cell, Light, Color blindness, Color vision, Color