A graph G is 2-stratified if its vertex set is partitioned into two classes (each of which is a stratum or a color class), where the vertices in one class are colored red and those in the other class are colored blue. Let F be a 2-stratified graph rooted at some blue vertex v. An F -coloring of a graph is a red-blue coloring of the vertices of G in which every blue vertex v belongs to a copy of...

Equiluminance ratios for red/green, red/blue and green/blue sine-wave gratings were determined by using a minimum-motion heterochromatic matching technique that permitted reliable settings at temporal frequencies as low as 0.5 Hz. The red/green equiluminance ratio was influenced by temporal but not spatial frequency, the green/blue ratio was influenced by spatial but not temporal frequency, and...

PURPOSE When the targets or the background in a display are different colors, longitudinal chromatic aberration ensures that there is no single correct accommodative response. The purpose of the present study was to determine whether the response becomes more variable when viewing certain multicolor displays. METHODS Accommodative responses of five young participants were measured with a dyna...

Given a set of points in the plane each colored either red or blue, we find non-self-intersecting geometric spanning cycles of the red points and of the blue points such that each edge of the red spanning cycle is crossed at most three times by the blue spanning cycle and vice-versa.

Fluorescence spectroscopy was used to characterize blue light responses from chloroplasts of adaxial guard cells from Pima cotton (Gossypium barbadense) and coleoptile tips from corn (Zea mays). The chloroplast response to blue light was quantified by measurements of the blue light-induced enhancement of a red light-stimulated quenching of chlorophyll a fluorescence. In adaxial (upper) guard ce...

The dynamics of color-coded signal transmission in the light-adapted Xenopus retina were studied by a combination of white noise (Wiener) analysis and simultaneous recordings from two types of horizontal cells: chromatic-type horizontal cells (C-HCs) are hyperpolarized by blue light and depolarized by red light, whereas luminosity-type horizontal cells (L-HCs) are hyperpolarized by all wave-len...

Let P2n be a point set in the plane with n red and n blue points. Let CR and CB (SR and SB) respectively be red and blue colored and disjoint disks (axisparallel squares). In this paper we prove the following results. Finding the positions for CR and CB that maximizes the number of red points covered by CR plus the number of blue points covered by CB can be done in O(n log n) time. Finding two ...

Consider a set of n points in <, each colored either red or blue. A line segment defined by two red points is a red segment, and that defined by two blue points is a blue segment. A bichromatic intersection is an intersection between a red segment and a blue segment. We give an O(n + k) algorithm that reports k bichromatic intersections defined by the n points. Extending our algorithm to points...

In 1930 Amako reported that as cultures of Serratia marcescens grew old their color changed from red to dark violet. He postulated that the change was associated with the pathway of pigment formation in the microorganism. Weiss (1949) observed a similar color change. Colonies growing on agar were orange-red in color at the end of 24 to 48 hr, but as they grew older the color changed to red-purp...

White leghorn chickens (Gallus Gallus) were isolated and reared in either white, half red and half blue, red, or blue cages, and at 60 hrs. and 120 hrs. were given a preference test for either a red or blue stationary object. Chicks housed in white cages were exposed to white throughout the experiment, and chicks housed in half red and half blue were exposed to red and blue in the same manner. ...