We give a new proof showing that it is NP-hard to color a 3-colorable graph using just four colors. This result is already known [18], but our proof is novel as it does not rely on the PCP theorem, while the one in [18] does. This highlights a qualitative difference between the known hardness result for coloring 3-colorable graphs and the factor n hardness for approximating the chromatic number...

aims: the synthetic colors are preferred by the food industry because of the variety of shades, intensity, uniformity, excellent solubility and stability. they are used in a variety of food products such as dairy products, beverages, baked products, confections and pet foods. food colors may have toxic effects on the human body. this study aimed to examine the amount of synthetic colors in some...

When an otherwise inconspicuous stimulus is learned to predict a reward, this stimulus will automatically capture visual attention. This learned attentional bias is not specific to the precise object previously associated with reward, but can be observed for different stimuli that share a defining feature with the reward cue. Under certain circumstances, value-driven attentional biases can even...

A new color coordinate system, which describes color by means of brightness, hue and saturation, is presented. The relative distance from the body diagonal to the nearest surface of the RGB color cube is used as the saturation. The conversions from and to the RGB space are described. Keywords—colour coordinate system, brightness, hue, saturation

Although humans can discriminate millions of colors, language typically refers to color using a limited number of discrete categories (e.g., red, green, blue). Color categories are not only present in language (color terms), they are also present in “thought.” For example, at least under some circumstances, adults’ perceptual or cognitive judgments of color (e.g., color memory, search, or simil...

Facial expressions of emotion in humans are believed to be produced by contracting one's facial muscles, generally called action units. However, the surface of the face is also innervated with a large network of blood vessels. Blood flow variations in these vessels yield visible color changes on the face. Here, we study the hypothesis that these visible facial colors allow observers to successf...

In a reverse Stroop task, observers respond to the meaning of a color word irrespective of the color in which the word is printed-for example, the word red may be printed in the congruent color (red), an incongruent color (e.g., blue), or a neutral color (e.g., white). Although reading of color words in this task is often thought to be neither facilitated by congruent print colors nor interfere...

People interpret abstract meanings from colors, which makes color a useful perceptual feature for visual communication. This process is complicated, however, because there is seldom a one-to-one correspondence between colors and meanings. One color can be associated with many different concepts (one-to-many mapping) and many colors can be associated with the same concept (many-to-one mapping). ...

nima yoshij and badr shaker sayyab are two contemporary renowned poet in iran and iraq which using the concepts of the verious colors could show their own personal and social opinion at their poets. no doubt, personal experiences, litererary life and the political and social environment surrounding of each poet can affect the role of the colors in his poems. similar pretty or horrible incident ...