We have examined the timing of calling behavior in the female Egyptian cotton leafworm, Spodoptera littoralis and its modification by exposure to sex pheromone. The calling rhythm of the female moth was found to be circadian, persistent for at least 4days once it has been entrained, and could be phase ...

We investigated issues that could impair the capacity of multifocal pupilliographic perimetry to detect visual field damage. Differential blue light absorbance causes between-subject variance so we compared stimuli with differing blue content. We also quantified declining response gain at higher stimulus intensities (saturation), which can reduce sensitivity to changes in ...

Melatonin, a hormone produced by the pineal gland, is important for regulating circadian rhythms in many animals. Light at night causes an acute suppression of melatonin in nearly all vertebrate species. A previous study found that light failed to suppress melatonin in the lizard Anolis carolinensis. This is a surprising ...

Several species of terrestrial carnivores (Mammalia: Carnivora) have bold contrasting color patterns that, in some species, apparently signal possession of noxious anal gland secretions, or even physical strength and great ferocity; yet the evolutionary drivers of both placement and patterning of these contrasting pelage colors on the body, and the ...

The potential for iron(III) tartrate to act as a photoactivator in light induced oxidative degradation of white wine is described. Using a tartaric acid based model wine system containing 5 mg/L iron, exposure to light from a xenon-arc lamp led to the oxidative degradation of tartaric acid and the production ...

Digital photography can be used to measure skin color colorimetrically when combined with proper techniques. To better understand the settings of digital photography for the evaluation and measurement of skin colors, we used a tungsten lamp with filters and the custom white balance (WB) function of a digital camera. All ...

Contributions of initial and retained levels of oxygen consumption and reducing capacity to animal variation in color stability were evaluated. Instrumental color values were determined on longissimus steaks (n=257) during 6 d of display. Oxygen consumption (OC), nitric oxide metmyoglobin reduction (NORA), initial metmyoglobin formation (IMF), and post-reduction metmyoglobin (PRM) ...

Light elements must be present in the nearly pure iron core of the Earth to match the remotely observed properties of the outer and inner cores. Crystallization of the inner core excludes light elements from the solid, concentrating them in liquid near the inner-core boundary that potentially rises and collects ...

Color vision in mammals is based on the expression of at least two cone opsins that are sensitive to different wavelengths of light. Furthermore, retinal pathways conveying color-opponent signals are required for color discrimination. Most of the primates are trichromats, and "color-coded channels" of their retinas are unveiled to a ...

Color has become a premier model system for understanding how information is processed by neural circuits, and for investigating the relationships among genes, neural circuits, and perception. Both the physical stimulus for color and the perceptual output experienced as color are quite well characterized, but the neural mechanisms that underlie ...

The Moderate Resolution Imaging Spectroradiometer (MODIS) on the Aqua platform has nine spectral bands with center wavelengths from 412 to 870 nm that are used to produce the standard ocean color data products. Ocean scenes usually contain high contrast due to the presence of bright clouds over dark water. About ...

Warm-white LEDs (WLEDs) with high spectral quality and efficiency are required for lighting applications, but current experimental performances are limited. We report on nanocrystal quantum dot (NQD) hybridized WLEDs with high performance that exhibit a high luminous efficacy of optical radiation exceeding 350lm/W(opt) and a high color rendering index close ...

In response to ambient light levels, many lower vertebrates darken or lighten their body colors by regulating dispersion or aggregation, respectively, of melanin granules (melanosomes) in the melanophore. This physiological reaction is mediated by photoreception in the eyes, the pineal gland, the deep brain and the melanophores themselves, depending on ...

The aim of this study was to evaluate the influence of artificial accelerated aging on the color stability and opacity of composites of different shades. Four composites for direct use (Heliomolar, 4 Seasons, Tetric EvoCeram; QuiXfil) and one for indirect use (SR Adoro) in two shades were used: light (A2) ...

The durability of an organic color and its resistance against external chemical agents and exposure to light can be significantly enhanced by hybridizing the natural dye with a mineral. In search for stable natural pigments, the present work focuses on the association of indigo blue with several zeolitic matrices (LTA ...

Cryptic coloration is a classic example of evolution by natural selection. However, it has been studied almost exclusively in predator-prey systems, despite the fact that it may evolve in other groups, such as ectoparasites. The principle defense of hosts against ectoparasites is grooming behavior, which has a visual component. Host-imposed ...

The apparent color of an object within a scene depends on the spectrum of the light illuminating the object. However, recording an object's color independent of the illuminant spectrum is important in many machine vision applications. In this paper the performance of a blackbody-model-based color constancy algorithm that requires four ...

We estimated the number of colors perceived by color normal and color-deficient observers when looking at the theoretic limits of object-color stimuli. These limits, the optimal color stimuli, were computed for a color normal observer and CIE standard illuminant D65, and the resultant colors were expressed in the CIELAB and ...

Studies on human psychological domains associated with color specific light effects have been reported. The heart rate variability (HRV) has been suggested to be a useful tool for the detection of short-term effects of light on the autonomic nervous system (ANS). The emotional state of an individual has an independent ...

Penguin feathers are highly modified in form and function, but there have been no fossils to inform their evolution. A giant penguin with feathers was recovered from the late Eocene (~36 million years ago) of Peru. The fossil reveals that key feathering features, including undifferentiated primary wing feathers and broad ...

Optic neuritis related to multiple sclerosis and diabetic retinopathy are relatively selective post-retinal and retinal vision disorders. Vision impairment in both conditions is reliably measured by testing critical fusion frequency (CFF). To examine color vision, we measured the CFF in response to red and blue stimuli, and tested CFF values ...

We report on the light-emitting color barcode nanowires (LECB-NWs), which were fabricated by alternating the electrochemical polymerization of light-emitting polymers with various luminescence colors and efficiencies. The nanoscale photoluminescence characteristics of LECB-NWs were investigated using a laser confocal microscope with a high spatial resolution. The alternating light emissions of the ...

Conjugated polymers have been investigated for a number of applications in optoelectronics and sensing due to their important electronic and optical properties. For instance, polydiacetylene (PDA) may change color in response to external stimuli and has been extensively explored as a material for chromatic sensors. However, the practical applications of ...

A quarter of a century ago, the first systematic behavioral experiments were performed to clarify the nature of color constancy-the effect whereby the perceived color of a surface remains constant despite changes in the spectrum of the illumination. At about the same time, new models of color constancy appeared, along ...

We report a wavelength-compensated three-channel (RGB) joint transform correlator (JTC) for color pattern recognition using a ferroelectric liquid-crystal spatial light modulator (SLM) operating in binary pure phase modulation. We apply a previously reported time-multiplexing technique useful in creating wavelength-compensated diffraction patterns, based on the synchronization of properly scaled diffraction masks ...

Quantum yields of firefly bioluminescence reactions were determined for beetle luciferases from the three main families of luminous beetles emitting different bioluminescence colors. Quantum yield (QY) was significantly correlated with luminescence spectrum. The green light-emitting luciferase of the Brazilian click beetle, Pyrearinus termitilluminans, whose luminescence spectrum had the shortest peak ...

There have been significant advances in our understanding of mammalian color vision over the past 15 years. This paper reviews a number of topics that have been central to these recent efforts, including: (1) the extent and nature of ultraviolet vision in mammals, (2) the evolutionary loss of short-wavelength-sensitive cones ...

The color attributes of commercially available shade guides have been measured by spectrophotometers (SP), which are designed to measure flat surfaces. However, there is limited information on the color distribution of shade guides as measured by spectroradiometers (SR), which are capable of measuring the color of curved surfaces. The purpose ...

In this work it is suggested that color induces phenomenal wholeness, part-whole organization and fragmentation. The phenomenal wholeness subsumes the set of its main attributes: homogeneity, continuity, univocality, belongingness, and oneness. If color induces wholeness, it can also induce fragmentation. Therefore, in order to understand the role played by color ...

Earth pigments from the three excavations at Pinnacle Point Cave 13B (Western Cape Province, South Africa), spanning the terminal middle Pleistocene and earlier late Pleistocene, are described and analyzed. Qualitative geological categorization primarily rested on textural, fabric, and iron enrichment attributes. Comprehensive recovery allowed identification of non-anthropic pigmentaceous materials, questionable ...

We established a model for spectra of LEDs at different drive currents. The simulation program of color rendering of white-light LED clusters has been developed, according to the principle of additive color mixture. The experimental results show that white/red LED clusters can realize color temperature untunable white light with a ...

Visual filling-in occurs when a retinally stabilized object undergoes perceptual fading. As the term "filling-in" implies, it is commonly believed that information about the apparently vanished object is lost and replaced solely by information arising from the surrounding background. Here we report multivoxel pattern analysis fMRI data that challenge this ...

Image category recognition is important to access visual information on the level of objects and scene types. So far, intensity-based descriptors have been widely used for feature extraction at salient points. To increase illumination invariance and discriminative power, color descriptors have been proposed. Because many different descriptors exist, a structured ...

Despite a long-standing belief that insect pollinators can select for certain flower colors, there are few experimental demonstrations that free-flying insects choose between natural flowers based on color. We investigated responses of insect visitors to experimental manipulations of flower color in the New Zealand alpine. Native syrphid flies (Allograpta and ...

A model of adaptation and visual coding was used to simulate how color appearance might vary among individuals that differ only in their sensitivity to wavelength. Color responses to images were calculated for cone receptors with spectral sensitivities specific to the individual, and in postreceptoral mechanisms tuned to different combinations ...

We describe a fluorescent detection technique for a lab-on-a-chip flow cytometer. Fluorescent emission is encoded into a time-dependent signal as a fluorescent cell or bead traverses a waveguide array with integrated spatial filters and color filters. Different from conventional colored filters with well-defined transmission spectral window, the integrated color filters ...

Although a large body of scientific literature shows that background color and luminance affect color perception, previous measurements of tooth color difference thresholds have not taken the effects of viewing context into account. The present study tested the hypothesis that differences in skin/gingival color influence individuals' judgments of tooth color ...

A model for LED spectra at different drive currents is established. The simulation program of color rendering of a white-light LED cluster is developed according to the principle of additive color mixtures. The program can predict not only the spectral power distribution, chromaticity coordinates, correlated color temperature (CCT), and color ...

In this article, we report that in visual search, desaturated reddish targets are much easier to find than other desaturated targets, even when perceptual differences between targets and distractors are carefully equated. Observers searched for desaturated targets among mixtures of white and saturated distractors. Reaction times were hundreds of milliseconds ...

This article describes one experiment that studied the influence of Daytime Running Lamps (DRL) on pedestrian detection of turn indicators. An experimental device including one DRL and one turn indicator was used in order to determine Visual Reaction Times (VRT) of 148 observers in different situations involving turn indicator activation. ...

Color coordinates of translucent esthetic materials measured by traditional spectrophotometers (SP) would deviate from those measured by newly introduced spectroradiometers (SR), which might simulate the clinical viewing condition better. This study aimed to determine the correlations in the SP- and SR-based color coordinates and color differences of all-ceramic materials. Specimens ...

The potential anti-herbivory functions of colorful (red and yellow) autumn leaves received considerable attention in the last decade. The most studied and discussed is the co-evolutionary hypothesis, according to which autumn coloration signals the quality of defense to insects that migrate to the trees in autumn. In addition to classic ...

The aims of this study were to assess the utility of digital color sensing to quantify iris color using digital photographs and to determine whether gender or iris color affects the dark-adapted pupil diameter (DAPD). Subjects aged 18-80 years (N = 263) with no eye disease had their right DAPD ...

Metacontrast is a visual illusion in which the visibility of a target stimulus is virtually lost when immediately followed by a nonoverlapping mask stimulus. For a colored target, metacontrast is color-selective, with target visibility markedly reduced when the mask and target are the same color, but only slightly reduced when ...

Empowering silicon (Si) with optical functions constitutes a very important challenge in photonics. The scalable fabrication capabilities for this earth-abundant, environmentally friendly material are unmatched in sophistication and can be unleashed to realize a plethora of high-performance photonic functionalities that find application in information, bio-, display, camouflage, ornamental, and energy ...

Instead of developing a novel red phosphor individually, this work proposes the production of white light by combining a near-ultraviolet/ultraviolet diode chip with blue and special yellow phosphors: the yellow phosphor includes the red and green components with high color saturation. The availability of this scheme is demonstrated by preparing ...

Vasarely's 'nested-squares' illusion is the perception of a glowing "X" along the diagonals of concentric squares with a luminance gradient. We present here the chromatic Vasarely effect, where the concentric angles have a chromatic gradient, under iso-brightness conditions. The strength of the effect was tested psychophysically by two measures, the ...

Carotenoid-based yellowish to red plumage colors are widespread visual signals used in sexual and social communication. To understand their ultimate signaling functions, it is important to identify the proximate mechanism promoting variation in coloration. Carotenoid-based colors combine structural and pigmentary components, but the importance of the contribution of structural components ...

The general CIE color rendering index (CRI) of light is an important index to evaluate the quality of illumination. However, because of the complexity in measurement of the rendering ability under designated constraints, an approach for general mathematical formulation and global optimization of the rendering ability of light emitting diode ...

Coloration and color vision covary with lighting in many taxa. Determining the mechanisms underlying these patterns is difficult because lighting environments can have multiple effects on signaling that occur at multiple timescales. Lighting environments can (1) immediately affect signal propagation and transmission, which determine the radiance spectrum reaching the receiver; ...