High Color Contrast Research Articles

Optimizing Presentation of AdSense Ads within Blogs

AdSense text ads have become a popular method of advertising on the web, specifically within blogs when using Blogger. With increasing popularity of blogs, AdSense ads are enticing to bloggers because they offer financial rewards with relatively little effort. The biggest challenge with AdSense is generating revenue through clicks or impressions. Google offers tips on optimal presentation for ads to generate higher revenue, but empirical evidence is lacking in this area. Thus, the purpose of this study was to examine two important presentation elements of AdSense ads, location and color scheme. Results suggested more information is remembered about an AdSense ad when it has a high contrast color. Increased awareness can lead to higher recall of the ad, thereby, helping build the brand of advertiser which can increase clicks.

Optimizing Presentation of AdSense Ads within Blogs

AdSense text ads have become a popular method of advertising on the web, specifically within blogs when using Blogger. With increasing popularity of blogs, AdSense ads are enticing to bloggers because they offer financial rewards with relatively little effort. The biggest challenge with AdSense is generating revenue through clicks or impressions. Google offers tips on optimal presentation for ads to generate higher revenue, but empirical evidence is lacking in this area. Thus, the purpose of this study was to examine two important presentation elements of AdSense ads, location and color scheme. Results suggested more information is remembered about an AdSense ad when it has a high contrast color. Increased awareness can lead to higher recall of the ad, thereby, helping build the brand of advertiser which can increase clicks.

Cleaner gobies evolve advertising stripes of higher contrast

Elacatinus gobies of the Caribbean have undergone rapid speciation along ecological axes, and particular species from this genus act as 'cleaners' that remove ectoparasites from larger coral reef fish, termed 'clients'. Evolutionary shifts in habitat use, behavior and lateral body stripe colors differentiate cleaners from ancestral sponge-dwelling lineages. High-contrast stripe colors associated with cleaning behavior on coral reefs may have evolved as a signal of cleaning status. We asked whether cleaner gobies with blue stripes are more conspicuous than ancestral yellow- and green-stripe phenotypes to a diverse set of potential client visual systems in the tropical reef environment where cleaning stations are commonly observed. Using spectrophotometric measurements of cleaners with blue and yellow stripes and their F1 hybrid, we tested the contrast of each color stripe to both potential dichromatic and trichromatic reef fish visual systems, against typical coral and sponge microhabitat background colors. Blue stripes provide the highest average chromatic contrast across a range of possible microhabitat colors to the majority of fish visual systems tested. The contrast provided by yellow and hybrid green stripes are comparable across habitats to dichromatic visual systems. The green stripe is less contrasting than both blue and yellow to many potential trichromatic visual systems. We suggest that the evolution of blue stripes in Elacatinus gobies could be a result of natural selection for signals of high color contrast, driven by the sensory biases and visual systems of diverse reef fish clients.

Multicolor Polymer Disperse Microencapsulated Liquid Crystal Displays

This work develops a new technology to fabricate polymer-dispersed microencapsulated liquid crystal (PDMLC) devices using screen-printing, which is a low temperature procedure (about 90degC) for application on a soft plastic substrate. This research demonstrates numerically and in Mandarin, a 4.5-in multicolor PDMLC (MPDMLC) device with high color contrast, low electric consumption and flexible bending mechanical property. The current work coats three different color pastes (red, blue and black) on a single substrate. Their turn-on voltages are all as low as 5 V and saturation voltages are 20, 30, and 30 V for red, blue, and black colors, respectively.

Tuning the Electrochromic Properties of Poly(alkyl-3,4-ethylenedioxyselenophenes) Having High Contrast Ratio and Coloration Efficiency

A systematic study of the electrochemical, spectroelectrochemical and electrochromic (EC) properties of poly(alkyl-3,4-ethylenedioxyselenophene) (PEDOS-Cn) (n = 0, 2, 4, 6, 8 and 12) films is reported. The alkyl substituents lead PEDOS-Cn films to exhibit sharper redox peaks than the parent PEDOS film and raise an onset of their oxidation potentials by 0.20−0.62 V. As expected, the introduction of alkyl chains significantly improves the EC properties and the electrochemical stability of PEDOS-Cn films and results in high contrast ratios and coloration efficiencies, low switching voltages, and fast switching times. As the length of the alkyl chain increases, the broad absorption peak of PEDOS sharpens and splits into three distinct peaks for PEDOS-Cn films starting from n = 4. We have identified the correlations between EC properties (such as coloration efficiency) and other observed properties of PEDOS-Cn films (such as their peak width, the position of the maximum absorption peak, the ratio of the absorption intensity of NIR spectra peaks to visible spectra peaks) and the contrast ratio. Interestingly, EC properties show bell-shaped behavior as a function of alkyl chain length, which reaches the maximum for PEDOS-C6 film, whereas the EC properties of films with shorter and longer alkyl chains are poorer.

Hyperbranched and viologen-functionalized polyglycerols: preparation, photo- and electrochromic performance

Covalently bonding viologen groups at the chain-ends of hyperbranched polyglycerol would enhance the performance of viologen chromophores to external photo- and potential stimuli, because the amorphous, soft and hyperbranched polyether in globular conformation inhibits the aggregation or crystallization of the highly concentrated and ionic viologen chromophores, and also stabilizes the viologen cation radicals. Hyperbranched and functional polyglycerol containing viologen chromophores (HPG-V2+) are prepared by firstly capping the terminal hydroxyl groups of hyperbranched polyglycidol (HPG) with chloroacetyl, and then with the chloroacetyl groups and 4,4′-bipyridine to form the viologen chromophores on the chain-ends of HPG. The evolution of chemical structures from glycidols to HPG-V2+ is carefully characterized. The HPG-V2+ exhibits both photo- and electrochromism with high color contrast, short response time, and well stability: upon UV irradiation, the HPG-V2+ film changes its color from pale yellow to purple, while optical transmittance at 540 nm decreases from ≥90% to <10%; to the stimuli of pulsed 2.5 V electrical potential, the solution type electrochromic cell based on HPG-V2+ responds with reversible color changes from transparent to violet within about 0.52 s, much faster than the previously reported viologen-containing electrochromic polymers. The photochromism of HPG-V2+ is effective even in atmosphere by sunshine: when exposing to sunshine for several minutes the color of the HPG-V2+ film turned to purple, while low molecular weight viologen analogue exhibits only electrochromism.

Colorful methods to detect ion channels and pores: intravesicular chromogenic probes that respond to pH, pM and covalent capture

The activity of synthetic pores, ion channels, transporters and carriers is usually determined with fluorescent probes in vesicles or by conductance measurements in planar lipid bilayers. Elaborating on more colorful alternatives, we here introduce 5(6)-carboxynaphthofluorescein (CNF) as an intravesicular pH probe for the colorimetric detection of activity, selectivity and cooperativity of ion channels such as gramicidin A. We further report that intravesicular pyrocatechol violet (PV), together with extravesicular Cu2+, extravesicular 4-carboxyphenylboronic acid (CBA) or intravesicular 4-(benzyl-N-glutamate)boronic acid (BGBA) can detect the activity of synthetic pores or cell-penetrating peptide (CPP) sensors. Their response to analytes such as dodecylphosphate, hyaluronan or IP6 are reported as high-contrast color changes from yellow to blue, from yellow to red, or from red to green.

New Insights into Skin Appearance and Measurement

When viewing the human face, the eye is drawn automatically to the areas of uneven topography and high color contrast, and the perception of skin age and attractiveness is dependent on these features. Although it is well recognized that topographic features, such as lines and wrinkles, contribute to the perceived age of skin and many cosmetic procedures are directed toward modifying these, the contribution of color contrast to the perceived age of skin has been less widely studied. A new technique, spectrophotometric intracutaneous analysis, is able to measure and characterize the distribution of chromophores in aging human skin and represents a significant advance in evaluation of the role color contrast plays in perception of the aging human face. This technique may be useful in the assessment of cosmetic interventions to reduce the appearance of aging by modification of skin color.

Motion vision is independent of color in Drosophila

Whether motion vision uses color contrast is a controversial issue that has been investigated in several species, from insects to humans. We used Drosophila to answer this question, monitoring the optomotor response to moving color stimuli in WT and genetic variants. In the fly eye, a motion channel (outer photoreceptors R1-R6) and a color channel (inner photoreceptors R7 and R8) have been distinguished. With moving bars of alternating colors and high color contrast, a brightness ratio of the two colors can be found, at which the optomotor response is largely missing (point of equiluminance). Under these conditions, mutant flies lacking functional rhodopsin in R1-R6 cells do not respond at all. Furthermore, genetically eliminating the function of photoreceptors R7 and R8 neither alters the strength of the optomotor response nor shifts the point of equiluminance. We conclude that the color channel (R7/R8) does not contribute to motion detection as monitored by the optomotor response.

Aposematic colouration enhances memory formation in domestic chicks trained in a weak passive avoidance learning paradigm

The one-trial passive avoidance learning task is commonly used in avian research to explore anatomical, cellular and molecular parameters of learning and memory. Many factors are known to influence the effectiveness and/or duration of such learning events. Combinations of novel odours, such as pyrazine, and aposematic colours, such as brig ht yellow or red, have been shown to induce a long-lasting aversion to food crumbs in ‘visual’ predators, including birds such as the domestic chick (1). The aim of this study was to (a) examine whether visual complexity played a role in the generation of an aversive response to a novel visual stimulus and (b) to establish whether the duration of memory of an aversive experience could be modified by altering the visual properties of the stimulus. In the first experiment, naïve domestic chicks were trained on a weakly aversive one-trial passive avoidance bead task, in which chicks were allowed to peck at a bead coated with a 10% solution of the bitter-tasting and odorous substance methylanthranilate (MeA). The chicks were trained with (allowed to peck) one of four differently coloured beads dipped in 10% MeA. Chrome, black, yellow or black-and-yellow striped beads were used. ‘Recall’ of the aversive bead was examined by presenting the (clean) training bead 24 h after training and monitoring avoidance to it compared to a ‘neutral’ white bead. A high proportion (63%) of chicks trained with the black and yellow striped bead avoided it 24 h after training, whereas little or no avoidance was seen in response to chrome, yellow or black beads. In a second experiment naïve domestic chicks were all trained once only with a black and yellow striped bead coated in a 10% MeA solution, but this time, were tested 24 h later, once only, with either a black, a yellow or a black and yellow striped bead. Nearly 60% of chicks tested with a black and yellow striped bead showed avoidance of the bead, whereas only 23% of those tested with a black bead and 14% tested with a yellow bead showed avoidance. These results confirm the importance of complex warning colouration, when paired with a novel olfactory cue and a bitter taste, in avoidance learning. We conclude that the chicks’ response to monochromatic colours (e.g. yellow or black) is not affected by their previous experience with a conspicuously patterned stimulus (yellow and black stripes). Moreover, it suggests a predisposition for chicks to attend to aversive cues associated with ‘naturalistic’ high contrast colour cue combinations such as black and yellow.

Assessment of the visual impact of marble quarry expansion (1984–2000) on the landscape of Thasos island, NE Greece

Marble extraction is an economically important and widespread activity in Greece that exists since historical times. The extraction takes place by open-pit quarries in hill slopes. The original landform is permanently altered and the original vegetation cover is destroyed. The visual impact of the quarries extends over larger areas as noticeable scars of high colour contrast, reducing the aesthetic appeal of the landscape and deteriorating the scenic quality of areas where tourism often is a major constituent of income. The aim of this work was to assess the ecological, landscape and visual impacts of marble quarries on the island of Thasos, NE Greece by employing remote sensing, geographical analysis and landscape metrics. Change detection and object-based classification were used to monitor the landscape dynamics (1984–2000) of marble quarries. A new index was defined to estimate the ‘cumulative visibility load’ on the landscape. An expansion trend of marble quarries was identified by the creation of new and the enlargement of existing quarries in the NE part of the island on areas previously covered by semi-natural pine forest. The visual impact increased by a factor of 2.52 and although the area of quarries was less than 1% of the landscape in 2000, it affected 13.5% of the island, including areas such as the island's capital and nearby coasts.

Separating color from color contrast

Visual objects can be described by their color and by their color contrast. For example, a red disk in front of a white background appears "red with high color contrast," whereas a red disk in front of a slightly less-saturated red background will appear "red with low color contrast." This paper examines the visual response to color contrast in a cone-based color space. The stimulus consists of two disks whose chromaticity and/or luminance modulate in time along a line in a DKL color space; the chromaticity and luminance levels of the two disks are always identical. One disk is surrounded by a static ring whose color is at one end of the color line, and the other disk is surrounded by a static ring whose color is at the opposite end of the color line. The disks appear to modulate in antiphase (following the contrast information), yet they can also appear to be approximately the same color (following the chromatic/luminance information). The observers' task was to adjust the color angle of modulating disks until the antiphase appearance was eliminated-creating a contrast null. Observers set contrast nulls at a color angle approximately 90 deg away from the line connecting the colors of the surround rings; this result occurred in both chromoluminant and equiluminant color planes, although two observers showed a flattening near equiluminance in the chromoluminance planes. To account for the data, I present a model that contains one pathway for color and another pathway for color contrast. I show that (1) the model correctly predicts orthogonal directions in color space for the contrast nulling task; (2) the response of the contrast pathway appears to be faster than the response of the color pathway; (3) the response of the contrast pathway may mediate detection thresholds under some conditions (a finding that can account for some of the effects of surround luminance on temporal sensitivity); (4) the asynchronous modulation can be seen even when the stimulus is blurred; and (5) the asynchrony does not require a disk-ring configuration.

Dome lighting for insect imaging under a microscope

The most basic element of photography is the interaction of light with the subject being imaged. In cases where magnification and clarity are of great importance, such as the imaging of insects for scientific illustration, controlling light can be especially challenging. The intense light needed to reveal microscopic elements such as setae and ultrastructural sculpturing may often overcompensate the light levels needed in other areas, especially for high color contrast and/or reflective specimens. Projecting halogen fiber-optic lights over diffusers such as Mylar or Styrofoam is one method used to overcome this imbalance successfully; however, these methods typically involve a great deal of setup time and experience. Light-emitting diodes (LEDs) are a cheap, powerful, and energy-efficient light source that is now being used more frequently in the imaging of insects under a microscope. One technique that has shown promise for quick and effective insect imaging is using LEDs in conjunction with an open dome to create a diffused, soft light arena for photography. Though commercially available illumination domes exist, creating a dome lighting system of your own is in fact easy and inexpensive. We detail how a variety of dome systems can be made using easily acquired materials and identify a few important considerations for effectively imaging challenging subjects under a microscope.

A new triple staining method for double in situ hybridization in combination with cell lineage tracing in whole‐mount Xenopus embryos

To analyze cell to cell interaction effects on cell differentiation, we developed a new triple staining method for double in situ hybridization with cell lineage tracing in whole-mount Xenopus embryos. The method provides high color contrast views, and also enabled us to examine inside the embryos. Wild-type embryos whose blastomere(s) had been injected with a cell lineage tracer were cultured, fixed, hemisectioned when necessary, and first served for the double in situ hybridization, with two sequential chromogenic reactions. They were postfixed, and the labeled cells were retraced immunohistochemically. Finally, the pigment of the embryos was bleached to obtain a clear view. We applied this method to a blastomere transplantation experiment to examine whether the spatial gene expression patterns along the anteroposterior axis can be induced by cell to cell interactions. The presumptive organizer of a 32-cell embryo was replaced by the labeled presumptive epidermis of another synchronous embryo. The resultant triple-stained late gastrula showed quite similar anteroposterior expression patterns of gsc and Xbra to those of a normal embryo in the axial mesoderm derived from the transplanted presumptive epidermis, indicating that cell to cell interactions had induced these patterns.

A Novel Electrochromic Polymer Synthesized through Electropolymerization of a New Donor−Acceptor Bipolar System

We have synthesized a novel 9,9‘-spirobifluorene-cored donor−acceptor (D−A) bichromophore system in which the electron-donating (D) moieties are triphenylamine (TPA) and carbazole (CBZ) groups and the electron-withdrawing (A) moieties are 1,3,4-oxadiazole (OXD) groups. The electron-deficient OXD groups efficiently blocked the radical cations delocalization between the two terminal TPA groups, rendering the electropolymerization of the TPA groups feasible. The resulting polymer could be cross-linked further at higher oxidation potentials through electrodimerization occurring at the C3 and C6 positions of the CBZ group. The polymer film obtained exhibited reversible electrochemical oxidation, accompanied by strong color changes with high coloration efficiency and contrast ratio, which could be switched through potential modulation.

Novel Ultrathin Scanning Fiber Endoscope for Cholangioscopy and Pancreatoscopy

Cholangioscopy and pancreatoscopy have been limited by current endoscopic technology. “Mother-baby” endoscope combinations use expensive and fragile “baby” scopes with limited longevity. Traditional baby scopes utilize imaging bundles that are limited in image quality (resolution, contrast, and color saturation). We have developed a new type of ultrathin, flexible endoscope or catheterscope that does not tradeoff a reduction in image quality with a reduction in scope diameter. The current forward-viewing prototype images at 500 lines resolution in a highly flexible 1.6 mm diameter shaft with a 13-mm long rigid tip. Full-color images are acquired at 15 Hz and with 80 degrees field of view in air or liquid. A prototype has been developed for ERCP. The prototype catheter scope was tested using a therapeutic duodenoscope in a synthetic human model (LM-014, Koken Co., Tokyo, Japan). The prototype was easily inserted into the pancreatic duct using direct visualization. This catheterscope is an example of a new technology platform for endoscopy. The core technology is a micro-optical scanner, less than 1 mm in diameter and less than 13 mm in length when sealed behind an objective lens system. The scanner is a singlemode optical fiber that is vibrated at its mechanical resonance by a 0.4 mm diameter piezoelectric tube. High-contrast color images are acquired by scanning red, green, and blue laser light in a spiral scan pattern (>200,000 pixels). The backscattered light is collected by a ring of 12 plastic optical fibers (0.25 mm diameter, Edmund Optics, Barrington, NJ) and detected by photomultiplier tubes in the portable base station. Low light levels are used for imaging, 2 mW per wavelength, which is equivalent to a laser pointer. A 1.6 mm diameter polyethylene sheath allows highly flexible bending of the shaft (6-mm minimum bend radius). The scanning fiber technology is versatile for many future endoscopic applications. Magnification endoscopy is possible by electronically reducing the scanning amplitude while acquiring 500-line images. Software can increase or decrease image resolution (to the optical limit) with a tradeoff in image frame rate. During insertion and navigation, the imaging can occur at higher frame rates (30 Hz) to minimize any motion distortion. During endoscopic examination, imaging can be at higher resolution (1000 lines per image). Fluorescence and narrow-band imaging are possible by adding appropriate laser excitation sources and additional filters and detectors in the base station. The authors acknowledge support for development of the catheterscope from the PENTAX Corporation and NIH/NCI CA094303.

Synthesis and Properties of a Novel Electrochromic Polymer Obtained from the Electropolymerization of a 9,9'-Spirobifluorene-Bridged Donor−Acceptor (D−A) Bichromophore System

The synthesis and photophysical, electrochemical, and spectroelectrochemical characterization of a novel donor−acceptor (D−A) bichromophore system composed of two D−A segments linking through a spiro center are reported. The electron-donating (D) moieties are triphenylamine (TPA) groups, whereas the electron-withdrawing (A) moieties are cyano groups. The particular “spiro” configuration that perpendicularly bonds the D−A chromophores by a tetrahedral carbon, impedes orbital interactions between the branches. Thus, the two TPA substituents act independently, rendering an efficient electropolymerization process feasible. The polymer film obtained showed reversible electrochemical oxidation accompanied by strong color changes with high coloration efficiency and contrast ratio, which can be switched by potential modulation. The remarkable electrochromic behavior of the film is clearly interpreted on the basis of spectroelectrochemical studies. A plausible polymerization mechanism involved with the TPA dimerization reaction is proposed for the electropolymerization process.

The effects of pattern symmetry on detection of disruptive and background-matching coloration

Two, logically distinct but sometimes compatible, mechanisms of camouflage are background-matching and disruptive coloration. In the former, an animal’s coloration comprises a random sample of the background, and so target‐background discrimination is impeded. In the latter, object or feature recognition is compromised by placing bold, high-contrast colors so that they break up the prey’s body into apparently unconnected objects. Recent experimental evidence for the utility of disruptive colors, above and beyond that conferred by background matching, has been based on artificial prey with patterns lacking a plane of symmetry. However, it is plausible that the bilateral symmetry present in natural prey may compromise the efficiency of disruptive coloration, on account of the potency of symmetry as a cue in visual search. In this study, we tested this prediction in the field, by tracking the ‘‘survival’’ under bird predation of artificial mothlike targets placed on oak trees. These had background-matching color patches placed either disruptively or nondisruptively and with or without bilateral symmetry. We found that symmetry reduced the effectiveness of both nondisruptive and disruptive background-matching coloration to a similar degree so that the negative effects of symmetry on concealment are no greater for disruptive than nondisruptive patterns. Key words: bird vision, camouflage, crypsis, disruptive coloration, symmetry, visual search. [Behav Ecol]

Layer-by-Layer Assembled Electrochromic Film Based on an Alkylsulfonated Polyaniline

An alkylsulfonated polyaniline, poly(aniline-N-butylsulfonate)s (PANBS), was assembled by the layer-by-layer (LBL) assembling technique as an electroactive anionic polymers for the layering. The counter ions for PANBS layer were polyaniline (H+ doped) and vinylbenzyldimethyl-n-alkylammonium salts (VBAA) as the conductive and insulating polycation, respectively. High color contrast was observed when the electrochromic (EC) film was composed alternatively of the PANBS/PAN and PANBS/VBAA layer. Interlayer insulating gap controlled by the alkyl chain length of VBAA, was an important factor to increase EC response of the window assembled by the LBL method.

Electrochromic properties of nanochromic windows assembled by the layer-by-layer self-assembly technique

Abstract Nanostructure controlled electrochromic (EC) multilayer films were assembled by the layer-by-layer (LBL) technique using poly(aniline-N-butylsulfonate)s (PANBUS) as polyanion, and vinyl benzyl dimethyl alkyl ammonium-chloride (VBDA) and polyaniline as the counter cation. The building up of such multilayer films on an indium-tin oxide (ITO) substrate was characterized by the increment of the absorbance through UV–Vis spectroscopy and layer thickness. Electrochromic response was highly dependent on the alkylchain length of VBDA. Higher color contrast was observed when the EC film was prepared from the VBDA having a shorter alkylchain length. An all-solid-state EC display showed EC response at 3 V within 5 s with a stable memory effect.