Ultraviolet plumage colors predict mate preferences in starlings

Avian plumage has long been used to test theories of sexual selection, with humans assessing the colors, However, many birds see in the ultraviolet (<400 nm), to which humans are blind, Consequently, it is important to know whether natural variation in UV reflectance from plumage functions in sexual signaling, We show that female starlings rank males differently when UV wavelengths are present or absent, Principal component analysis of approximate to 1300 reflectance spectra (300-700 nm) taken from sexually dimorphic plumage regions of males predicted preference under the UV+ treatment. Under UV- conditions, females ranked males in a different and nonrandom order, but plumage reflectance in the human visible spectrum did not predict choice, Natural variation in UV reflectance is thus important in avian mate assessment, and the prevailing light environment can have profound effects on observed mating preferences.

Internal structure and pigment granules in colored alpaca fibers

Alpaca fibers have some distinct properties such as softness and warmth, which have not been fully understood in combination with the fiber internal structures. In the present investigation, the internal structures of alpaca fibers have been closely examined under the scanning electron microscope (SEM), especially in the longitudinal direction. The results showed that numerous pigment granules reside loosely inside pockets in brown and dark-brown alpaca fibers. These pigment granules were mainly distributed inside the cortical cells, the medullation regions as well as underneath the cuticles. Their size in the brown alpaca fibers was smaller and more uniformly round than in the dark-brown fibers. These granules in colored alpaca fibers loosen the bundle of cortical cells, providing many crannies in the fibers which may contribute to the superior flexibility, warmth and softness of the fibers. Moreover, there are no heavy metal elements found in the granules. The mordant hydrogen peroxide bleaching employed could eliminate the pigment granules and create many nano-volumes for further dyeing of fibers into more attractive colors.

Inhibition and facilitation in schizotypy

Participants scoring high and low on a schizotypy scale (n = 18 in each group) switched between naming words and naming colors in a Stroop task in congruent, neutral, and incongruent conditions. The findings were that, while being slower and less accurate overall than low schizotypes, the high schizotypy group did not display disproportionately greater Stroop inhibition or facilitation, suggesting intact selective attention. However, the high schizotypy group suffered disproportionately larger switching costs. The results provide evidence for similarities between schizotypy and schizophrenia, specifically that the problem in schizotypy is to do with switching rather than selecting attention, because of a difficulty either in selecting task-relevant information or in inhibiting inappropriate response alternatives.

Color map-based image fusion

An image fusion system accepts two source images and produces a 'better' fused image. The term 'better' differs from one context to another. In some contexts, it means holding more information. In other contexts, it means getting more accurate results or readings. In general, images hold more than just the color values. Histogram distribution, dynamic range of colors, and color maps are all as valuable as the color values presenting the pictorial information of the image. This paper studies the problems of fusing images from different domains. It proposes a method to extend the fusion algorithms to fuse image properties that define the interpretation of captured images as well.

Afternoon T : Testosterone level is higher in red than yellow male polychromatic lizards

Recent work on within-species polymorphism across a broad range of taxa has renewed and considerably increased the attention to this classic evolutionary area, notably in lizard species where colors covary with reproductive strategies. We demonstrate elsewhere that red-headed males beat yellow-headed males in staged contests for females in the Australian painted dragon lizard Ctenophorus pictus. This morph difference in behaviour is linked to what appears to be a convention of red dominance in male–male interactions set very early in ontogeny, long before coloration has developed. In the current note, we investigate the relationship between time of day, which is directly linked to vigilance time in territorial males, and plasma levels of testosterone and corticosterone. We show that red males have higher testosterone levels in late afternoon following a day of territory patrolling and a non-significant trend in plasma corticosterone levels that decline with time of day. In conclusion, there are significant differences in testosterone profile between the two color morphs, providing a potential proximate link to the behavioural differences between them.

Avian color vision and coloration : multidisciplinary evolutionary biology

A fundamental issue in biology is explaining the diversity of coloration found in nature. Birds provide some of the best-studied examples of the evolution and causes of color variation and some of the most arresting color displays in the natural world. They possess perhaps the most richly endowed visual system of any vertebrate, including UV-A sensitivity and tetrachromatic color vision over the 300-700-nm waveband. Birds provide model systems for the multidisciplinary study of animal coloration and color vision. Recent advances in understanding avian coloration and color vision are due to recognition that birds see colors in a different way than humans do and to the ready availability of small spectrometers. We summarize the state of the current field, recent trends, and likely future directions.

Iridescent structurally based coloration of eyespots correlates with mating success in the peacock

Gaudy plumage coloration is a widespread ornamental trait in birds and thought to be sexually selected. Although much attention has been devoted to structural coloration reflecting in UV, the signaling function of structural colors lacking UV reflectance and those that exhibit iridescence coloration are poorly documented. The train of the peacock (Pavo cristatus), a classical example of a sexually selected trait, is composed of iridescent structurally colored eyespots not reflecting in UV. Until today, the role played by the structural color of the eyespots in female mate choice has never been investigated using spectrometry. We measured eyespot coloration from a stationary angle (static coloration) and the change in coloration resulting from different angles (iridescent coloration). We assessed coloration with reflectance spectrometry, and we analyzed reflectance spectra using 2 methods. First, we extracted the reflectance spectra shape descriptors hue, brightness, and chroma. Second, we computed color and brightness contrasts signaled by eyespot feathers, taking peafowl color visual sensitivity into account. Iridescence was estimated by the maximal change for all parameters. Brightness was correlated with male mating success. The maximal change in color contrast was correlated with both the frequency of male visitation by females and male mating success. These results suggest that peahens can use both static and dynamic (i.e., iridescent) aspects of plumage structural coloration as signals to detect and choose their mates.

Application of computational media aesthetics methodology to extracting color semantics in film

Using film grammar as the underpinning, we study the extraction of structures in video based on color using a wide configuration of clustering methods combined with existing and new similarity measures. We study the visualisation of these structures, which we call Scene-Cluster Temporal Charts and show how it can bring out the interweaving of different themes and settings in a film. We also extract color events that filmmakers use to draw/force a viewer's attention to a shot/scene. This is done by first extracting a set of colors used rarely in film, and then building a probabilistic model for color event detection. We demonstrate with experimental results from ten movies that our algorithms are effective in the extraction of both scene-cluster temporal charts and color events.

Review: The preliminary study for the interpretation of electrochemical noise with continuous wavelet transform

Random fluctuations of the electrical quantities (electrode potential and cell current) in electrochemical systems commonly are referred to as electrochemical noise (ECN). The ECN signal for the corrosion of mild steel in reinforced concrete specimen was analyzed with the Continuous Wavelet Transform (CWT). The original signal was transformed into a time-frequency phase plane with colors representing the coefficients of the CWT. The signal shows a self-similarity structure in the phase plane. Through this way, the chaotic nature of corrosion process is manifested.

Image reconstruction using Loop subdivision

It is an ultimate objective to reconstruct an image with high quality using a compact representation, which is the basic step in image-manipulation fields. We propose an effective vectorization based approach to reconstruct an image using a triangular mesh associated with Loop subdivision scheme in the present paper. With an initial control mesh obtained by simplifying a dense mesh from a quality-preserved triangulation, we produce the final optimal control mesh by optimizing a mesh over topologies and colors to approximate the given image. The main advantages of the approach include: (1) the reconstruction of an image is not restricted to be aligned with image coordinate axes; (2) a high order continuous function is defined over a triangle instead of a bilinear interpolation; (3) it is a compact and vector-based representation easy to edit and transmit. Experimental results are presented to confirm the effectiveness of the method. Comparisons with the bi-cubic spline and the mesh simplification methods demonstrate the merits of our method in reconstruction quality and representation size.

Coloration of cotton fibers with anisotropic silver nanoparticles

Anisotropic silver nanoparticles were assembled on cotton fibers to realize the coloration of cotton. The assembly of silver nanoparticles on fibers was achieved by linking of poly(diallyldimethylammonium chloride) (PDDA) at room temperature. The silver nanoparticle treated cotton showed different colors because of localized surface plasmon resonance (LSPR) property of silver nanoparticles. The coloration was completed through electrostatic interaction between the PDDA treated cotton surface and the anisotropic silver nanoparticles in the reaction system. Scanning electron microscopy (SEM) characterization demonstrated that the morphologies of silver nanoparticles remained unchanged during the coloration process, so the treated cotton inherited the LSPR optical features of silver nanoparticles. Moreover, the cotton colorated with silver nanoparticles showed reasonably good color fastness to washing, which will facilitate the practical application of this coloration process.

Developing an empirical algorithm for protecting text-based CAPTCHAs against segmentation attacks

In this paper, we aim to provide an effective and efficient method to generate text-based Captchas which are resilient against segmentation attack. Different to the popular industry practice of using very simple color schemes, we advocate to use multiple colors in our Captchas. We adopt the idea of brush and canvas when coloring our Captchas. Furthermore, we choose to use simple accumulating functions to achieve diffusion on painted colors and DES encryption to achieve a good level of confusion on the brush pattern. To facilitate ordinary users and developers, we propose an empirical algorithm with support of Taguchi method to guarantee the quality of the chosen color schemes. Our proposed methodology has at least three advantages — 1) the settings of color schemes can be fully customized by the user or developer; 2) the quality of selected colors have desirable statistical features that are ensured by Taguchi method; 3) the algorithm can be fully automated into computer programs. Moreover, our included examples and experiments prove the practicality and validity of our algorithm.

Haptic-based color representation framework

In this paper we propose a novel technique to associate color RGB dimensions into other dimensions that can be explored Haptically. These dimensions will be the force, vibration and geometric representation. The color association between the color information and the other modalities will be called the Haptic-Color Palette. This is of great importance for visually impaired and color blind persons to get access to media in which colors play a great role, such as artwork. The proposed color conversion technique is based on the human perception and interpretations of colors.