Colour formation on the wings of the butterfly Hypolimnas salmacis by scale stacking.

PubMed

Siddique, Radwanul Hasan; Vignolini, Silvia; Bartels, Carolin; Wacker, Irene; Hölscher, Hendrik

2016-11-02

The butterfly genus Hypolimnas features iridescent blue colouration in some areas of its dorsal wings. Here, we analyse the mechanisms responsible for such colouration on the dorsal wings of Hypolimnas salmacis and experimentally demonstrate that the lower thin lamina in the white cover scales causes the blue iridescence. This outcome contradicts other studies reporting that the radiant blue in Hypolimnas butterflies is caused by complex ridge-lamellar architectures in the upper lamina of the cover scales. Our comprehensive optical study supported by numerical calculation however shows that scale stacking primarily induces the observed colour appearance of Hypolimnas salmacis.

Yellow and the Novel Aposematic Signal, Red, Protect Delias Butterflies from Predators

PubMed Central

Wee, Jocelyn Liang Qi

2017-01-01

Butterflies of the South Asian and Australian genus Delias possess striking colours on the ventral wings that are presumed to serve as warning signals to predators. However, this has not been shown empirically. Here we experimentally tested whether the colours of one member of this diverse genus, Delias hyparete, function as aposematic signals. We constructed artificial paper models with either a faithful colour representation of D. hyparete, or with all of its colours converted to grey scale. We also produced models where single colours were left intact, while others were converted to grey-scale or removed entirely. We placed all model types simultaneously in the field, attached to a live mealworm, and measured relative attack rates at three separate field sites. Faithful models of D. hyparete, suffered the least amount of attacks, followed by grey-scale models with unaltered red patches, and by grey-scale models with unaltered yellow patches. We conclude that red and yellow colours function as warning signals. By mapping dorsal and ventral colouration onto a phylogeny of Delias, we observed that yellow and red colours appear almost exclusively on the ventral wing surfaces, and that basal lineages have mostly yellow, white, and black wings, whereas derived lineages contain red colour in addition to the other colours. Red appears to be, thus, a novel adaptive trait in this lineage of butterflies. PMID:28060944

Yellow and the Novel Aposematic Signal, Red, Protect Delias Butterflies from Predators.

PubMed

Wee, Jocelyn Liang Qi; Monteiro, Antónia

2017-01-01

Butterflies of the South Asian and Australian genus Delias possess striking colours on the ventral wings that are presumed to serve as warning signals to predators. However, this has not been shown empirically. Here we experimentally tested whether the colours of one member of this diverse genus, Delias hyparete, function as aposematic signals. We constructed artificial paper models with either a faithful colour representation of D. hyparete, or with all of its colours converted to grey scale. We also produced models where single colours were left intact, while others were converted to grey-scale or removed entirely. We placed all model types simultaneously in the field, attached to a live mealworm, and measured relative attack rates at three separate field sites. Faithful models of D. hyparete, suffered the least amount of attacks, followed by grey-scale models with unaltered red patches, and by grey-scale models with unaltered yellow patches. We conclude that red and yellow colours function as warning signals. By mapping dorsal and ventral colouration onto a phylogeny of Delias, we observed that yellow and red colours appear almost exclusively on the ventral wing surfaces, and that basal lineages have mostly yellow, white, and black wings, whereas derived lineages contain red colour in addition to the other colours. Red appears to be, thus, a novel adaptive trait in this lineage of butterflies.

Colour formation on the wings of the butterfly Hypolimnas salmacis by scale stacking

PubMed Central

Siddique, Radwanul Hasan; Vignolini, Silvia; Bartels, Carolin; Wacker, Irene; Hölscher, Hendrik

2016-01-01

The butterfly genus Hypolimnas features iridescent blue colouration in some areas of its dorsal wings. Here, we analyse the mechanisms responsible for such colouration on the dorsal wings of Hypolimnas salmacis and experimentally demonstrate that the lower thin lamina in the white cover scales causes the blue iridescence. This outcome contradicts other studies reporting that the radiant blue in Hypolimnas butterflies is caused by complex ridge-lamellar architectures in the upper lamina of the cover scales. Our comprehensive optical study supported by numerical calculation however shows that scale stacking primarily induces the observed colour appearance of Hypolimnas salmacis. PMID:27805005

Poseidon's paintbox : historical archives of ocean colour in global-change perspective

NASA Astrophysics Data System (ADS)

Wernand, M. R.

2011-11-01

In the thesis introduction issues are discussed on the historical background of marine optics and on marine optical devices that were used over the past centuries to observe and measure; as in all sciences, in marine optics we can see a steady development: that of ‘measuring’, beginning many centuries ago, to 'knowing' and since less than a century to the understanding of the phenomenon. Hereafter, six themes are treated successively. The first theme, ‘Ocean optics from 1600 (Hudson) to 1930 (Raman), shift in interpretation of natural water colouring’, addresses the question of why it took so long a time to explain the phenomenon ‘the colouring of the sea’, especially the blue colour, despite the age-long interest of sailors, for practical purposes of navigation and detection of fish - of which more later. The second theme ‘On the history of the Secchi disc’, describes the search to establish methods for the determination of (sea) water clarity concerning purposes of navigation (near coast colour changes) just mentioned to detect shoals, and for a more basic purpose, tracing lost objects. The search to determine the clarity of lakes and seas culminated in the invention of the Secchi disc, used since the late 19th century. The third theme, ‘Spectral analysis of the Forel-Ule ocean colour comparator scale’, addresses the accuracy of a colour scale proposed, used in limnology and oceanography. Scale observations are put into perspective with contemporary measurements on the colour of the sea. The fourth theme, ‘Ocean colour changes in the North Pacific since 1930’, handles the question whether long-term ocean colour changes using historic Forel-Ule observations, in this part of the ocean made very frequently over time, can be determined in relation to global change. In principal global warming may cause a gradual change in ocean colour due to the effect of biological, chemical and physical aspects of the ocean-surface. The fifth theme, ‘MERIS-based ocean colour classification using the Forel-Ule scale’, addresses the question whether a relation can be established between the old Forel-Ule methodology, the classification of ocean colour by means of one of the scale colours, and the more recent satellite ocean colour methodology. The sixth theme, ‘Trends in ocean colour and chlorophyll concentration since 1889 to present’, addresses decadal colour changes per ocean and sea, using the longest available Forel-Ule dataset and confirms the possibility to transform these colour changes into chlorophyll concentration (indicative of the biomass of marine planktonic microalgae) changes. Such a transformation is needed to provide a link to the present in which chlorophyll concentrations are determined by using new technologies such as satellite remote sensing calibrated with high-performance liquid chromatography (HPLC) pigment analysis to determine marine microalgae pigments.

Diurnal lighting patterns and habitat alter opsin expression and colour preferences in a killifish

PubMed Central

Johnson, Ashley M.; Stanis, Shannon; Fuller, Rebecca C.

2013-01-01

Spatial variation in lighting environments frequently leads to population variation in colour patterns, colour preferences and visual systems. Yet lighting conditions also vary diurnally, and many aspects of visual systems and behaviour vary over this time scale. Here, we use the bluefin killifish (Lucania goodei) to compare how diurnal variation and habitat variation (clear versus tannin-stained water) affect opsin expression and the preference to peck at different-coloured objects. Opsin expression was generally lowest at midnight and dawn, and highest at midday and dusk, and this diurnal variation was many times greater than variation between habitats. Pecking preference was affected by both diurnal and habitat variation but did not correlate with opsin expression. Rather, pecking preference matched lighting conditions, with higher preferences for blue at noon and for red at dawn/dusk, when these wavelengths are comparatively scarce. Similarly, blue pecking preference was higher in tannin-stained water where blue wavelengths are reduced. In conclusion, L. goodei exhibits strong diurnal cycles of opsin expression, but these are not tightly correlated with light intensity or colour. Temporally variable pecking preferences probably result from lighting environment rather than from opsin production. These results may have implications for the colour pattern diversity observed in these fish. PMID:23698009

The effect of polyploidy and hybridization on the evolution of floral colour in Nicotiana (Solanaceae)

PubMed Central

McCarthy, Elizabeth W.; Arnold, Sarah E. J.; Chittka, Lars; Le Comber, Steven C.; Verity, Robert; Dodsworth, Steven; Knapp, Sandra; Kelly, Laura J.; Chase, Mark W.; Baldwin, Ian T.; Kovařík, Aleš; Mhiri, Corinne; Taylor, Lin; Leitch, Andrew R.

2015-01-01

Background and Aims Speciation in angiosperms can be accompanied by changes in floral colour that may influence pollinator preference and reproductive isolation. This study investigates whether changes in floral colour can accompany polyploid and homoploid hybridization, important processes in angiosperm evolution. Methods Spectral reflectance of corolla tissue was examined for 60 Nicotiana (Solanaceae) accessions (41 taxa) based on spectral shape (corresponding to pigmentation) as well as bee and hummingbird colour perception in order to assess patterns of floral colour evolution. Polyploid and homoploid hybrid spectra were compared with those of their progenitors to evaluate whether hybridization has resulted in floral colour shifts. Key Results Floral colour categories in Nicotiana seem to have arisen multiple times independently during the evolution of the genus. Most younger polyploids displayed an unexpected floral colour, considering those of their progenitors, in the colour perception of at least one pollinator type, whereas older polyploids tended to resemble one or both of their progenitors. Conclusions Floral colour evolution in Nicotiana is weakly constrained by phylogeny, and colour shifts do occur in association with both polyploid and homoploid hybrid divergence. Transgressive floral colour in N. tabacum has arisen by inheritance of anthocyanin pigmentation from its paternal progenitor while having a plastid phenotype like its maternal progenitor. Potentially, floral colour evolution has been driven by, or resulted in, pollinator shifts. However, those polyploids that are not sympatric (on a regional scale) with their progenitor lineages are typically not divergent in floral colour from them, perhaps because of a lack of competition for pollinators. PMID:25979919

Detection and discrimination of colour, a comparison of physiological and psychophysical data

NASA Astrophysics Data System (ADS)

Valberg, A.; Lee, B. B.

1989-01-01

Whereas the physiological basis of colorimetry (colour matches) is well understood in terms of the trireceptor theory of colour vision, colour discrimination and scaling still lack a comparable foundation. We present here experimental data that demonstrate how sensitivity and responsiveness of different types of cone-opponent and non-opponent cells of the macaque monkey correlate with human threshold sensitivity on the one hand, and how they in combination can be used to construct a suprathreshold equidistant colour space. Psychophysical thresholds correlate well with the threshold envelope of the most sensitive cells when stimuli are projected upon a steady white background. Detection thresholds for stimuli of differing wavelength and purity (saturation) generally indicate a transition from a phasic non-opponent system to a tonic opponent system of on-centre cells as purity increases. Detection and chromatic discrimination thresholds coincide only for long and short wavelengths of high purity, whereas they differ for mid-spectral lights. Different cell types may thus support detection and discrimination with different stimuli. With chromatic scaling of surface colours on the other hand, when stimuli are darker than an adaptation field still other cell types are needed. We demonstrate that it is possible, from a combination of on- and off-opponent cells, to reconstruct a uniform colour space, using summed outputs of cells with the same cone combination and vector addition for cells with different combinations. Different hues are represented by opponent cells with inputs from different cone types, the hue percept being related to the ratio of the activities of these cell systems.

Evaluation of hardness and colour change of soft liners after accelerated ageing.

PubMed

Mancuso, Daniela Nardi; Goiato, Marcelo Coelho; Zuccolotti, Bruna Carolina Rossatti; Moreno, Amália; dos Santos, Daniela Micheline

2009-07-01

Soft liners have been developed to offer comfort to denture wearers. However, this comfort is compromised when there is a change in the properties of the material, causing colour change, solubility, absorption and hardening. These characteristics can compromise the longevity of soft liners. The aim of this in vitro study was to investigate the effect of ageing on both the hardness and colour change of two soft liners following accelerated ageing. Two denture liners, one resin based (Trusoft, Bosworth, Illinois, USA) and one silicone based (Ufi Gel P, Voco GMBH, Cuxhaven, Germany), were tested in this study for both hardness (using the Shore A scale) and colour change (using the CIE L*a*b* colour scale), initially and after 1008 hours (6 weeks) of accelerated ageing. Statistical analysis was performed using the unpaired t-test with the Welch correction. These indicated that both materials increased in hardness and underwent colour change after accelerated ageing. The initial hardness of Trusoft was far lower than that of Ufi Gel P (18.2 Shore A units vs 34.8 Shore A units). However, for Trusoft the changes for both hardness (from 18.2 to 52.1 Shore A units) and colour change (16.85 on the CIE L*a*b* colour scale) were greater than those for Ufi Gel P, for which hardness changed from 34.8 to 36.5 Shore A units and the colour change was 5.19 on the CIE L*a*b* colour scale. Ufi Gel P underwent less hardness and colour change after accelerated ageing than Trusoft. On the other hand, the use of Trusoft may be preferable in cases where initial softness is a major consideration, such as when relining an immediate denture after implant surgery.

Pterin pigment granules are responsible for both broadband light scattering and wavelength selective absorption in the wing scales of pierid butterflies

PubMed Central

Morehouse, Nathan I; Vukusic, Peter; Rutowski, Ron

2006-01-01

A small but growing literature indicates that many animal colours are produced by combinations of structural and pigmentary mechanisms. We investigated one such complex colour phenotype: the highly chromatic wing colours of pierid butterflies including oranges, yellows and patterns which appear white to the human eye, but strongly absorb the ultraviolet (UV) wavelengths visible to butterflies. Pierids produce these bright colours using wing scales that contain collections of minute granules. However, to date, no work has directly characterized the molecular composition or optical properties of these granules. We present results that indicate these granules contain pterin pigments. We also find that pterin granules increase light reflection from single wing scales, such that wing scales containing denser granule arrays reflect more light than those with less dense granule collections. As male wing scales contain more pterin granules than those of females, the sexual dichromatism found in many pierid species can be explained by differences in wing scale pterin deposition. Additionally, the colour pattern elements produced by these pterins are known to be important during mating interactions in a number of pierid species. Therefore, we discuss the potential relevance of our results within the framework of sexual selection and colour signal evolution. PMID:17164199

A living mesoscopic cellular automaton made of skin scales.

PubMed

Manukyan, Liana; Montandon, Sophie A; Fofonjka, Anamarija; Smirnov, Stanislav; Milinkovitch, Michel C

2017-04-12

In vertebrates, skin colour patterns emerge from nonlinear dynamical microscopic systems of cell interactions. Here we show that in ocellated lizards a quasi-hexagonal lattice of skin scales, rather than individual chromatophore cells, establishes a green and black labyrinthine pattern of skin colour. We analysed time series of lizard scale colour dynamics over four years of their development and demonstrate that this pattern is produced by a cellular automaton (a grid of elements whose states are iterated according to a set of rules based on the states of neighbouring elements) that dynamically computes the colour states of individual mesoscopic skin scales to produce the corresponding macroscopic colour pattern. Using numerical simulations and mathematical derivation, we identify how a discrete von Neumann cellular automaton emerges from a continuous Turing reaction-diffusion system. Skin thickness variation generated by three-dimensional morphogenesis of skin scales causes the underlying reaction-diffusion dynamics to separate into microscopic and mesoscopic spatial scales, the latter generating a cellular automaton. Our study indicates that cellular automata are not merely abstract computational systems, but can directly correspond to processes generated by biological evolution.

A living mesoscopic cellular automaton made of skin scales

NASA Astrophysics Data System (ADS)

Manukyan, Liana; Montandon, Sophie A.; Fofonjka, Anamarija; Smirnov, Stanislav; Milinkovitch, Michel C.

2017-04-01

In vertebrates, skin colour patterns emerge from nonlinear dynamical microscopic systems of cell interactions. Here we show that in ocellated lizards a quasi-hexagonal lattice of skin scales, rather than individual chromatophore cells, establishes a green and black labyrinthine pattern of skin colour. We analysed time series of lizard scale colour dynamics over four years of their development and demonstrate that this pattern is produced by a cellular automaton (a grid of elements whose states are iterated according to a set of rules based on the states of neighbouring elements) that dynamically computes the colour states of individual mesoscopic skin scales to produce the corresponding macroscopic colour pattern. Using numerical simulations and mathematical derivation, we identify how a discrete von Neumann cellular automaton emerges from a continuous Turing reaction-diffusion system. Skin thickness variation generated by three-dimensional morphogenesis of skin scales causes the underlying reaction-diffusion dynamics to separate into microscopic and mesoscopic spatial scales, the latter generating a cellular automaton. Our study indicates that cellular automata are not merely abstract computational systems, but can directly correspond to processes generated by biological evolution.

Methodology for constructing a colour-difference acceptability scale.

PubMed

Laborie, Baptiste; Viénot, Françoise; Langlois, Sabine

2010-09-01

Observers were invited to report their degree of satisfaction on a 6-point semantic scale with respect to the conformity of a test colour with a white reference colour, simultaneously presented on a PDP display. Eight test patches were chosen along each of the +a*, -a*, +b*, -b* axes of the CIELAB chromaticity plane, at Y = 80 ± 2 cd.m(-2) . Experimental conditions reliably represented the automotive environment (patch size, angular distance between patches) and observers could move their head and eyes freely. We have compared several methods of category scaling, the Torgerson-DMT method (Torgerson, W. S. (1958). Theory and methods of scaling. Wiley, New York, USA); two versions of the regression method i.e. Bonnet's (Bonnet, C. (1986). Manuel pratique de psychophysique. Armand Colin, Paris, France) and logistic regression; and the medians method. We describe in detail a case where all methods yield substantial but slightly different results. The solution proposed by the regression method which works with incomplete matrices and yields results directly on a colorimetric scale is probably the most useful in this industrial context. Finally we summarize the implementation of the logistic regression method over four hues and for one experimental condition. © 2010 The Authors, Ophthalmic and Physiological Optics © 2010 The College of Optometrists.

The effect of polyploidy and hybridization on the evolution of floral colour in Nicotiana (Solanaceae).

PubMed

McCarthy, Elizabeth W; Arnold, Sarah E J; Chittka, Lars; Le Comber, Steven C; Verity, Robert; Dodsworth, Steven; Knapp, Sandra; Kelly, Laura J; Chase, Mark W; Baldwin, Ian T; Kovařík, Aleš; Mhiri, Corinne; Taylor, Lin; Leitch, Andrew R

2015-06-01

Speciation in angiosperms can be accompanied by changes in floral colour that may influence pollinator preference and reproductive isolation. This study investigates whether changes in floral colour can accompany polyploid and homoploid hybridization, important processes in angiosperm evolution. Spectral reflectance of corolla tissue was examined for 60 Nicotiana (Solanaceae) accessions (41 taxa) based on spectral shape (corresponding to pigmentation) as well as bee and hummingbird colour perception in order to assess patterns of floral colour evolution. Polyploid and homoploid hybrid spectra were compared with those of their progenitors to evaluate whether hybridization has resulted in floral colour shifts. Floral colour categories in Nicotiana seem to have arisen multiple times independently during the evolution of the genus. Most younger polyploids displayed an unexpected floral colour, considering those of their progenitors, in the colour perception of at least one pollinator type, whereas older polyploids tended to resemble one or both of their progenitors. Floral colour evolution in Nicotiana is weakly constrained by phylogeny, and colour shifts do occur in association with both polyploid and homoploid hybrid divergence. Transgressive floral colour in N. tabacum has arisen by inheritance of anthocyanin pigmentation from its paternal progenitor while having a plastid phenotype like its maternal progenitor. Potentially, floral colour evolution has been driven by, or resulted in, pollinator shifts. However, those polyploids that are not sympatric (on a regional scale) with their progenitor lineages are typically not divergent in floral colour from them, perhaps because of a lack of competition for pollinators. © The Author 2015. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Multiple Illuminant Colour Estimation via Statistical Inference on Factor Graphs.

PubMed

Mutimbu, Lawrence; Robles-Kelly, Antonio

2016-08-31

This paper presents a method to recover a spatially varying illuminant colour estimate from scenes lit by multiple light sources. Starting with the image formation process, we formulate the illuminant recovery problem in a statistically datadriven setting. To do this, we use a factor graph defined across the scale space of the input image. In the graph, we utilise a set of illuminant prototypes computed using a data driven approach. As a result, our method delivers a pixelwise illuminant colour estimate being devoid of libraries or user input. The use of a factor graph also allows for the illuminant estimates to be recovered making use of a maximum a posteriori (MAP) inference process. Moreover, we compute the probability marginals by performing a Delaunay triangulation on our factor graph. We illustrate the utility of our method for pixelwise illuminant colour recovery on widely available datasets and compare against a number of alternatives. We also show sample colour correction results on real-world images.

Colour evaluation of a phycobiliprotein-rich extract obtained from Nostoc PCC9205 in acidic solutions and yogurt.

PubMed

de O Moreira, Isabela; Passos, Thaís S; Chiapinni, Claudete; Silveira, Gabrielle K; Souza, Joana C M; Coca-Vellarde, Luis Guillermo; Deliza, Rosires; de Lima Araújo, Kátia G

2012-02-01

Phycobiliproteins are coloured proteins produced by cyanobacteria, which have several applications because of their colour properties. However, there is no available information about the colour stability of phycobiliproteins from Nostoc sp. in food systems. The aim of this work was to study the colour stability of a purple-coloured phycobiliprotein-rich extract from the cyanobacterium Nostoc PCC9205 in acidic solutions and yogurt. Variations of pH for Nostoc PCC9205 extract have shown stability for the L* (lightness) and a* (redness) indexes in the range 1.0-7.0. The b* index (blueness), however, increased at pH values below 4.0, indicating loss of the blue colour. The Nostoc PCC9205 extract was used as colorant in yogurt (pH 4.17) stored for 60 days. Instrumental colour analysis showed no changes for the L* and a* indexes during storage, whereas the b* index changed after 20 days of storage. A multiple comparison test showed colour instability after 20 days of storage. A hedonic scale test performed on the 60th day of storage showed acceptability of the product. The red component of the phycobiliprotein-rich extract from Nostoc PCC9205 presented an improved stability in acidic media and yogurt compared with the blue component of this extract. Copyright © 2011 Society of Chemical Industry.

Modelling vehicle colour and pattern for multiple deployment environments

NASA Astrophysics Data System (ADS)

Liggins, Eric; Moorhead, Ian R.; Pearce, Daniel A.; Baker, Christopher J.; Serle, William P.

2016-10-01

Military land platforms are often deployed around the world in very different climate zones. Procuring vehicles in a large range of camouflage patterns and colour schemes is expensive and may limit the environments in which they can be effectively used. As such this paper reports a modelling approach for use in the optimisation and selection of a colour palette, to support operations in diverse environments and terrains. Three different techniques were considered based upon the differences between vehicle and background in L*a*b* colour space, to predict the optimum (initially single) colour to reduce the vehicle signature in the visible band. Calibrated digital imagery was used as backgrounds and a number of scenes were sampled. The three approaches used, and reported here are a) background averaging behind the vehicle b) background averaging in the area surrounding the vehicle and c) use of the spatial extension to CIE L*a*b*; S-CIELAB (Zhang and Wandell, Society for Information Display Symposium Technical Digest, vol. 27, pp. 731-734, 1996). Results are compared with natural scene colour statistics. The models used showed good agreement in the colour predictions for individual and multiple terrains or climate zones. A further development of the technique examines the effect of different patterns and colour combinations on the S-CIELAB spatial colour difference metric, when scaled for appropriate viewing ranges.

Wing scale microstructures and nanostructures in butterflies--natural photonic crystals.

PubMed

Vértesy, Z; Bálint, Zs; Kertész, K; Vigneron, J P; Lousse, V; Biró, L P

2006-10-01

The aim of our study was to investigate the correlation between structural colour and scale morphology in butterflies. Detailed correlations between blue colour and structure were investigated in three lycaenid subfamilies, which represent a monophylum in the butterfly family Lycaenidae (Lepidoptera): the Coppers (Lycaeninae), the Hairstreaks (Theclinae) and the Blues (Polyommatinae). Complex investigations such as spectral measurements and characterization by means of light microscopy, scanning electron microscopy and transmission electron microscopy enabled us to demonstrate that: (i) a wide array of nanostructures generate blue colours; (ii) monophyletic groups use qualitatively similar structures; and (iii) the hue of the blue colour is characteristic for the microstructure and nanostructure of the body of the scales.

Laser-induced plasmonic colours on metals

NASA Astrophysics Data System (ADS)

Guay, Jean-Michel; Calà Lesina, Antonino; Côté, Guillaume; Charron, Martin; Poitras, Daniel; Ramunno, Lora; Berini, Pierre; Weck, Arnaud

2017-07-01

Plasmonic resonances in metallic nanoparticles have been used since antiquity to colour glasses. The use of metal nanostructures for surface colourization has attracted considerable interest following recent developments in plasmonics. However, current top-down colourization methods are not ideally suited to large-scale industrial applications. Here we use a bottom-up approach where picosecond laser pulses can produce a full palette of non-iridescent colours on silver, gold, copper and aluminium. We demonstrate the process on silver coins weighing up to 5 kg and bearing large topographic variations (~1.5 cm). We find that colours are related to a single parameter, the total accumulated fluence, making the process suitable for high-throughput industrial applications. Statistical image analyses of laser-irradiated surfaces reveal various nanoparticle size distributions. Large-scale finite-difference time-domain computations based on these nanoparticle distributions reproduce trends seen in reflectance measurements, and demonstrate the key role of plasmonic resonances in colour formation.

Laser-induced plasmonic colours on metals

PubMed Central

Guay, Jean-Michel; Calà Lesina, Antonino; Côté, Guillaume; Charron, Martin; Poitras, Daniel; Ramunno, Lora; Berini, Pierre; Weck, Arnaud

2017-01-01

Plasmonic resonances in metallic nanoparticles have been used since antiquity to colour glasses. The use of metal nanostructures for surface colourization has attracted considerable interest following recent developments in plasmonics. However, current top-down colourization methods are not ideally suited to large-scale industrial applications. Here we use a bottom-up approach where picosecond laser pulses can produce a full palette of non-iridescent colours on silver, gold, copper and aluminium. We demonstrate the process on silver coins weighing up to 5 kg and bearing large topographic variations (∼1.5 cm). We find that colours are related to a single parameter, the total accumulated fluence, making the process suitable for high-throughput industrial applications. Statistical image analyses of laser-irradiated surfaces reveal various nanoparticle size distributions. Large-scale finite-difference time-domain computations based on these nanoparticle distributions reproduce trends seen in reflectance measurements, and demonstrate the key role of plasmonic resonances in colour formation. PMID:28719576

Applying colour science in colour design

NASA Astrophysics Data System (ADS)

Luo, Ming Ronnier

2006-06-01

Although colour science has been widely used in a variety of industries over the years, it has not been fully explored in the field of product design. This paper will initially introduce the three main application fields of colour science: colour specification, colour-difference evaluation and colour appearance modelling. By integrating these advanced colour technologies together with modern colour imaging devices such as display, camera, scanner and printer, some computer systems have been recently developed to assist designers for designing colour palettes through colour selection by means of a number of widely used colour order systems, for creating harmonised colour schemes via a categorical colour system, for generating emotion colours using various colour emotional scales and for facilitating colour naming via a colour-name library. All systems are also capable of providing accurate colour representation on displays and output to different imaging devices such as printers.

First results from the IllustrisTNG simulations: the galaxy colour bimodality

NASA Astrophysics Data System (ADS)

Nelson, Dylan; Pillepich, Annalisa; Springel, Volker; Weinberger, Rainer; Hernquist, Lars; Pakmor, Rüdiger; Genel, Shy; Torrey, Paul; Vogelsberger, Mark; Kauffmann, Guinevere; Marinacci, Federico; Naiman, Jill

2018-03-01

We introduce the first two simulations of the IllustrisTNG project, a next generation of cosmological magnetohydrodynamical simulations, focusing on the optical colours of galaxies. We explore TNG100, a rerun of the original Illustris box, and TNG300, which includes 2 × 25003 resolution elements in a volume 20 times larger. Here, we present first results on the galaxy colour bimodality at low redshift. Accounting for the attenuation of stellar light by dust, we compare the simulated (g - r) colours of 109 < M⋆/M⊙ < 1012.5 galaxies to the observed distribution from the Sloan Digital Sky Survey. We find a striking improvement with respect to the original Illustris simulation, as well as excellent quantitative agreement with the observations, with a sharp transition in median colour from blue to red at a characteristic M⋆ ˜ 1010.5 M⊙. Investigating the build-up of the colour-mass plane and the formation of the red sequence, we demonstrate that the primary driver of galaxy colour transition is supermassive black hole feedback in its low accretion state. Across the entire population the median colour transition time-scale Δtgreen is ˜1.6 Gyr, a value which drops for increasingly massive galaxies. We find signatures of the physical process of quenching: at fixed stellar mass, redder galaxies have lower star formation rates, gas fractions, and gas metallicities; their stellar populations are also older and their large-scale interstellar magnetic fields weaker than in bluer galaxies. Finally, we measure the amount of stellar mass growth on the red sequence. Galaxies with M⋆ > 1011 M⊙ which redden at z < 1 accumulate on average ˜25 per cent of their final z = 0 mass post-reddening; at the same time, ˜18 per cent of such massive galaxies acquire half or more of their final stellar mass while on the red sequence.

Global Interior Robot Localisation by a Colour Content Image Retrieval System

NASA Astrophysics Data System (ADS)

Chaari, A.; Lelandais, S.; Montagne, C.; Ahmed, M. Ben

2007-12-01

We propose a new global localisation approach to determine a coarse position of a mobile robot in structured indoor space using colour-based image retrieval techniques. We use an original method of colour quantisation based on the baker's transformation to extract a two-dimensional colour pallet combining as well space and vicinity-related information as colourimetric aspect of the original image. We conceive several retrieving approaches bringing to a specific similarity measure [InlineEquation not available: see fulltext.] integrating the space organisation of colours in the pallet. The baker's transformation provides a quantisation of the image into a space where colours that are nearby in the original space are also nearby in the output space, thereby providing dimensionality reduction and invariance to minor changes in the image. Whereas the distance [InlineEquation not available: see fulltext.] provides for partial invariance to translation, sight point small changes, and scale factor. In addition to this study, we developed a hierarchical search module based on the logic classification of images following rooms. This hierarchical module reduces the searching indoor space and ensures an improvement of our system performances. Results are then compared with those brought by colour histograms provided with several similarity measures. In this paper, we focus on colour-based features to describe indoor images. A finalised system must obviously integrate other type of signature like shape and texture.

Mechanisms of structural colour in the Morpho butterfly: cooperation of regularity and irregularity in an iridescent scale.

PubMed Central

Kinoshita, Shuichi; Yoshioka, Shinya; Kawagoe, Kenji

2002-01-01

Structural colour in the Morpho butterfly originates from submicron structure within a scale and, for over a century, its colour and reflectivity have been explained as interference of light due to the multilayer of cuticle and air. However, this model fails to explain the extraordinarily uniform colour of the wing with respect to the observation direction. We have performed microscopic, optical and theoretical investigations, and have found that the separate lamellar structure with irregular heights is extremely important. Using a simple model, we have shown that the combined action of interference and diffraction is essential for the structural colour of the Morpho butterfly. PMID:12137569

Colour vision impairment is associated with disease severity in multiple sclerosis.

PubMed

Martínez-Lapiscina, Elena H; Ortiz-Pérez, Santiago; Fraga-Pumar, Elena; Martínez-Heras, Eloy; Gabilondo, Iñigo; Llufriu, Sara; Bullich, Santiago; Figueras, Marc; Saiz, Albert; Sánchez-Dalmau, Bernardo; Villoslada, Pablo

2014-08-01

Colour vision assessment correlates with damage of the visual pathway and might be informative of overall brain damage in multiple sclerosis (MS). The objective of this paper is to investigate the association between impaired colour vision and disease severity. We performed neurological and ophthalmic examinations, as well as magnetic resonance imaging (MRI) and optical coherence tomography (OCT) analyses, on 108 MS patients, both at baseline and after a follow-up of one year. Colour vision was evaluated by Hardy, Rand and Rittler plates. Dyschromatopsia was defined if colour vision was impaired in either eye, except for participants with optic neuritis (ON), for whom only the unaffected eye was considered. We used general linear models adjusted for sex, age, disease duration and MS treatment for comparing presence of dyschromatopsia and disease severity. Impaired colour vision in non-ON eyes was detected in 21 out of 108 patients at baseline. At baseline, patients with dyschromatopsia had lower Multiple Sclerosis Functional Composite (MSFC) scores and Brief Repeatable Battery-Neuropsychology executive function scores than those participants with normal colour vision. In addition, these patients had thinner retinal nerve fiber layer (RNFL), and smaller macular volume, normalized brain volume and normalized gray matter volume (NGMV) at baseline. Moreover, participants with incident dyschromatopsia after one-year follow-up had a greater disability measured by the Expanded Disability Status Scale and MSFC-20 and a greater decrease in NGMV than participants with normal colour vision. Colour vision impairment is associated with greater MS severity. © The Author(s) 2013.

Solvent-free optical recording of structural colours on pre-imprinted photocrosslinkable nanostructures

NASA Astrophysics Data System (ADS)

Jiang, Hao; Rezaei, Mohamad; Abdolahi, Mahssa; Kaminska, Bozena

2017-09-01

Optical digital information storage media, despite their ever-increasing storage capacity and data transfer rate, are vulnerable to the potential risk of turning inaccessible. For this reason, long-term eye-readable full-colour optical archival storage is in high demand for preserving valuable information from cultural, intellectual, and scholarly resources. However, the concurrent requirements in recording colours inexpensively and precisely, and preserving colours for the very long term (for at least 100 years), have not yet been met by existing storage techniques. Structural colours hold the promise to overcome such challenges. However, there is still the lack of an inexpensive, rapid, reliable, and solvent-free optical patterning technique for recording structural colours. In this paper, we introduce an enabling technique based on optical and thermal patterning of nanoimprinted SU-8 nanocone arrays. Using photocrosslinking and thermoplastic flow of SU-8, diffractive structural colours of nanocone arrays are recorded using ultra-violet (UV) exposure followed by the thermal development and reshaping of nanocones. Different thermal treatment procedures in reshaping nanocones are investigated and compared, and two-step progressive baking is found to allow the controllable reshaping of nanocones. The height of the nanocones and brightness of diffractive colours are modulated by varying the UV exposure dose to enable grey-scale patterning. An example of recorded full-colour image through half-tone patterning is also demonstrated. The presented technique requires only low-power continuous-wave UV light and is very promising to be adopted for professional and consumer archival storage applications.

The role of enamel thickness and refractive index on human tooth colour.

PubMed

Oguro, Rena; Nakajima, Masatoshi; Seki, Naoko; Sadr, Alireza; Tagami, Junji; Sumi, Yasunori

2016-08-01

To investigate the role of enamel thickness and refractive index (n) on tooth colour. The colour and enamel thickness of fifteen extracted human central incisors were determined according to CIELab colour scale using spectrophotometer (Crystaleye) and swept-source optical coherence tomography (SS-OCT), respectively. Subsequently, labial enamel was trimmed by approximately 100μm, and the colour and remaining enamel thickness were investigated again. This cycle was repeated until dentin appeared. Enamel blocks were prepared from the same teeth and their n were obtained using SS-OCT. Multiple regression analysis was performed to reveal any effects of enamel thickness and n on colour difference (ΔE00) and differences in colour parameters with CIELCh and CIELab colour scales. Multiple regression analysis revealed that enamel thickness (p=0.02) and n of enamel (p<0.001) were statistically significant predictors of ΔE00 after complete enamel trimming. The n was also a significant predictor of ΔH' (p=0.01). Enamel thickness and n were not statistically significant predictors of ΔL', ΔC', Δa* and Δb*. Enamel affected tooth colour, in which n was a statistically significant predictor for tooth colour change. Understanding the role of enamel in tooth colour could contribute to development of aesthetic restorative materials that mimic the colour of natural tooth with minimal reduction of the existing enamel. Copyright © 2016 Elsevier Ltd. All rights reserved.

Methods for assessing reliability and validity for a measurement tool: a case study and critique using the WHO haemoglobin colour scale.

PubMed

White, Sarah A; van den Broek, Nynke R

2004-05-30

Before introducing a new measurement tool it is necessary to evaluate its performance. Several statistical methods have been developed, or used, to evaluate the reliability and validity of a new assessment method in such circumstances. In this paper we review some commonly used methods. Data from a study that was conducted to evaluate the usefulness of a specific measurement tool (the WHO Colour Scale) is then used to illustrate the application of these methods. The WHO Colour Scale was developed under the auspices of the WHO to provide a simple portable and reliable method of detecting anaemia. This Colour Scale is a discrete interval scale, whereas the actual haemoglobin values it is used to estimate are on a continuous interval scale and can be measured accurately using electrical laboratory equipment. The methods we consider are: linear regression, correlation coefficients, paired t-tests plotting differences against mean values and deriving limits of agreement; kappa and weighted kappa statistics, sensitivity and specificity, an intraclass correlation coefficient and the repeatability coefficient. We note that although the definition and properties of each of these methods is well established inappropriate methods continue to be used in medical literature for assessing reliability and validity, as evidenced in the context of the evaluation of the WHO Colour Scale. Copyright 2004 John Wiley & Sons, Ltd.

Iridescent colour production in hairs of blind golden moles (Chrysochloridae).

PubMed

Snyder, Holly K; Maia, Rafael; D'Alba, Liliana; Shultz, Allison J; Rowe, Karen M C; Rowe, Kevin C; Shawkey, Matthew D

2012-06-23

Relative to other metazoans, the mammalian integument is thought to be limited in colour. In particular, while iridescence is widespread among birds and arthropods, it has only rarely been reported in mammals. Here, we examine the colour, morphology and optical mechanisms in hairs from four species of golden mole (Mammalia: Chrysochloridae) that are characterized by sheens ranging from purple to green. Microspectrophotometry reveals that this colour is weak and variable. Iridescent hairs are flattened and have highly reduced cuticular scales, providing a broad and smooth surface for light reflection. These scales form multiple layers of light and dark materials of consistent thickness, strikingly similar to those in the elytra of iridescent beetles. Optical modelling suggests that the multi-layers produce colour through thin-film interference, and that the sensitivity of this mechanism to slight changes in layer thickness and number explains colour variability. While coloured integumentary structures are typically thought to evolve as sexual ornaments, the blindness of golden moles suggests that the colour may be an epiphenomenon resulting from evolution via other selective factors, including the ability to move and keep clean in dirt and sand.

Spatial variation in colour morph, spotting and allozyme frequencies in the candy-stripe spider, Enoplognatha ovata (Theridiidae) on two Swedish archipelagos.

PubMed

Oxford, G S; Gunnarsson, B

2006-01-01

The selective significance, if any, of many invertebrate visible polymorphisms is still not fully understood. Here we examine colour- and black spotting-morph frequencies in the spider Enoplognatha ovata in populations on two Swedish archipelagos with respect to different spatial scales and, in one archipelago, against the background of variation at four putative neutral allozyme marker loci. Every population studied was polymorphic for colour and 28 out of 30 contained all three colour morphs--lineata, redimita and ovata. We found no evidence for a breakdown in the traditional colour morph designation previously suggested for other northern European populations of this species. For colour there is no significant heterogeneity at spatial scales greater than between local populations within islands. Black spotting frequencies show a similar lack of pattern over larger spatial scales except that there are significant differences between the Stockholm and Göteborg archipelagos. Measures of population differentiation (theta) within the Stockholm islands for the two visible systems show them to be significantly more differentiated than the neutral markers, suggesting local selection acting on them in a population-specific manner. On the basis of previous observations and the distribution of spotting phenotypes on a European scale, it is argued that thermal selection might operate on black spotting during the juvenile stages favouring more spots in continental climates. It is not clear what selective forces act on colour.

Classifying Natural Waters with the Forel-Ule Colour Index System: Results, Applications, Correlations and Crowdsourcing.

PubMed

Garaba, Shungudzemwoyo P; Friedrichs, Anna; Voß, Daniela; Zielinski, Oliver

2015-12-18

Societal awareness of changes in the environment and climate has grown rapidly, and there is a need to engage citizens in gathering relevant scientific information to monitor environmental changes due to recognition that citizens are a potential source of critical information. The apparent colour of natural waters is one aspect of our aquatic environment that is easy to detect and an essential complementary optical water quality indicator. Here we present the results and explore the utility of the Forel-Ule colour index (FUI) scale as a proxy for different properties of natural waters. A FUI scale is used to distinguish the apparent colours of different natural surface water masses. Correlation analysis was completed in an effort to determine the constituents of natural waters related to FUI. Strong correlations with turbidity, Secchi-disk depth, and coloured dissolved organic material suggest the FUI is a good indicator of changes related to other constituents of water. The increase in the number of tools capable of determining the FUI colours, (i) ocean colour remote sensing products; (ii) a handheld scale; and (iii) a mobile device app, make it a versatile relative measure of water quality. It has the potential to provide higher spatial and temporal resolution of data for a modernized classification of optical water quality. This FUI colour system has been favoured by several scientists in the last century because it is affordable and easy to use and provides indicative information about the colour of water and the water constituents producing that colour. It is therefore within the scope of a growing interest in the application and usefulness of basic measurement methodologies with the potential to provide timely benchmark information about the environment to the public, scientists and policymakers.

Classifying Natural Waters with the Forel-Ule Colour Index System: Results, Applications, Correlations and Crowdsourcing

PubMed Central

Garaba, Shungudzemwoyo P.; Friedrichs, Anna; Voß, Daniela; Zielinski, Oliver

2015-01-01

Societal awareness of changes in the environment and climate has grown rapidly, and there is a need to engage citizens in gathering relevant scientific information to monitor environmental changes due to recognition that citizens are a potential source of critical information. The apparent colour of natural waters is one aspect of our aquatic environment that is easy to detect and an essential complementary optical water quality indicator. Here we present the results and explore the utility of the Forel-Ule colour index (FUI) scale as a proxy for different properties of natural waters. A FUI scale is used to distinguish the apparent colours of different natural surface water masses. Correlation analysis was completed in an effort to determine the constituents of natural waters related to FUI. Strong correlations with turbidity, Secchi-disk depth, and coloured dissolved organic material suggest the FUI is a good indicator of changes related to other constituents of water. The increase in the number of tools capable of determining the FUI colours, (i) ocean colour remote sensing products; (ii) a handheld scale; and (iii) a mobile device app, make it a versatile relative measure of water quality. It has the potential to provide higher spatial and temporal resolution of data for a modernized classification of optical water quality. This FUI colour system has been favoured by several scientists in the last century because it is affordable and easy to use and provides indicative information about the colour of water and the water constituents producing that colour. It is therefore within the scope of a growing interest in the application and usefulness of basic measurement methodologies with the potential to provide timely benchmark information about the environment to the public, scientists and policymakers. PMID:26694444

Global skin colour prediction from DNA.

PubMed

Walsh, Susan; Chaitanya, Lakshmi; Breslin, Krystal; Muralidharan, Charanya; Bronikowska, Agnieszka; Pospiech, Ewelina; Koller, Julia; Kovatsi, Leda; Wollstein, Andreas; Branicki, Wojciech; Liu, Fan; Kayser, Manfred

2017-07-01

Human skin colour is highly heritable and externally visible with relevance in medical, forensic, and anthropological genetics. Although eye and hair colour can already be predicted with high accuracies from small sets of carefully selected DNA markers, knowledge about the genetic predictability of skin colour is limited. Here, we investigate the skin colour predictive value of 77 single-nucleotide polymorphisms (SNPs) from 37 genetic loci previously associated with human pigmentation using 2025 individuals from 31 global populations. We identified a minimal set of 36 highly informative skin colour predictive SNPs and developed a statistical prediction model capable of skin colour prediction on a global scale. Average cross-validated prediction accuracies expressed as area under the receiver-operating characteristic curve (AUC) ± standard deviation were 0.97 ± 0.02 for Light, 0.83 ± 0.11 for Dark, and 0.96 ± 0.03 for Dark-Black. When using a 5-category, this resulted in 0.74 ± 0.05 for Very Pale, 0.72 ± 0.03 for Pale, 0.73 ± 0.03 for Intermediate, 0.87±0.1 for Dark, and 0.97 ± 0.03 for Dark-Black. A comparative analysis in 194 independent samples from 17 populations demonstrated that our model outperformed a previously proposed 10-SNP-classifier approach with AUCs rising from 0.79 to 0.82 for White, comparable at the intermediate level of 0.63 and 0.62, respectively, and a large increase from 0.64 to 0.92 for Black. Overall, this study demonstrates that the chosen DNA markers and prediction model, particularly the 5-category level; allow skin colour predictions within and between continental regions for the first time, which will serve as a valuable resource for future applications in forensic and anthropologic genetics.

Colour Doppler and microbubble contrast agent ultrasonography do not improve cancer detection rate in transrectal systematic prostate biopsy sampling.

PubMed

Taverna, Gianluigi; Morandi, Giovanni; Seveso, Mauro; Giusti, Guido; Benetti, Alessio; Colombo, Piergiuseppe; Minuti, Francesco; Grizzi, Fabio; Graziotti, Pierpaolo

2011-12-01

What's known on the subject? and What does the study add? Transrectal gray-scale ultrasonography guided prostate biopsy sampling is the method for diagnosing prostate cancer (PC) in patients with an increased prostate specific antigen level and/or abnormal digital rectal examination. Several imaging strategies have been proposed to optimize the diagnostic value of biopsy sampling, although at the first biopsy nearly 10-30% of PC still remains undiagnosed. This study compares the PC detection rate when employing Colour Doppler ultransongraphy with or without the injection of SonoVue™ microbubble contrast agent, versus the transrectal ultrasongraphy-guided systematic biopsy sampling. The limited accuracy, sensitivity, specificity and the additional cost of using the contrast agent do not justify its routine application in PC detection. • To compare prostate cancer (PC) detection rate employing colour Doppler ultrasonography with or without SonoVue™ contrast agent with transrectal ultrasonography-guided systematic biopsy sampling. • A total of 300 patients with negative digital rectal examination and transrectal grey-scale ultrasonography, with PSA values ranging between 2.5 and 9.9 ng/mL, were randomized into three groups: 100 patients (group A) underwent transrectal ultrasonography-guided systematic bioptic sampling; 100 patients (group B) underwent colour Doppler ultrasonography, and 100 patients (group C) underwent colour Doppler ultrasonography before and during the injection of SonoVue™. • Contrast-enhanced targeted biopsies were sampled into hypervascularized areas of peripheral, transitional, apical or anterior prostate zones. • All the patients included in Groups B and C underwent a further 13 systematic prostate biopsies. The cancer detection rate was calculated for each group. • In 88 (29.3%) patients a histological diagnosis of PC was made, whereas 22 (7.4%) patients were diagnosed with high-grade prostatic intraepithelial neoplasia or atypical small acinar proliferation. • No significant differences were found among the three groups for cancer detection rate (P= 0.329). • Additionally, low sensitivity, specificity and accuracy of colour Doppler with or without SonoVue™ contrast agent were found. • Prostate cancer detection rate does not significantly improve with the use of colour Doppler ultrasonography with or without SonoVue™. • Although no collateral effects have been highlighted, the combined use of colour Doppler ultrasonography and SonoVue™ determines adjunctive costs and increases the mean time for taking a single prostate biopsy. © 2011 THE AUTHORS. BJU INTERNATIONAL © 2011 BJU INTERNATIONAL.

Spectrally tuned structural and pigmentary coloration of birdwing butterfly wing scales.

PubMed

Wilts, Bodo D; Matsushita, Atsuko; Arikawa, Kentaro; Stavenga, Doekele G

2015-10-06

The colourful wing patterns of butterflies play an important role for enhancing fitness; for instance, by providing camouflage, for interspecific mate recognition, or for aposematic display. Closely related butterfly species can have dramatically different wing patterns. The phenomenon is assumed to be caused by ecological processes with changing conditions, e.g. in the environment, and also by sexual selection. Here, we investigate the birdwing butterflies, Ornithoptera, the largest butterflies of the world, together forming a small genus in the butterfly family Papilionidae. The wings of these butterflies are marked by strongly coloured patches. The colours are caused by specially structured wing scales, which act as a chirped multilayer reflector, but the scales also contain papiliochrome pigments, which act as a spectral filter. The combined structural and pigmentary effects tune the coloration of the wing scales. The tuned colours are presumably important for mate recognition and signalling. By applying electron microscopy, (micro-)spectrophotometry and scatterometry we found that the various mechanisms of scale coloration of the different birdwing species strongly correlate with the taxonomical distribution of Ornithoptera species. © 2015 The Author(s).

Spectrally tuned structural and pigmentary coloration of birdwing butterfly wing scales

PubMed Central

Wilts, Bodo D.; Matsushita, Atsuko; Arikawa, Kentaro; Stavenga, Doekele G.

2015-01-01

The colourful wing patterns of butterflies play an important role for enhancing fitness; for instance, by providing camouflage, for interspecific mate recognition, or for aposematic display. Closely related butterfly species can have dramatically different wing patterns. The phenomenon is assumed to be caused by ecological processes with changing conditions, e.g. in the environment, and also by sexual selection. Here, we investigate the birdwing butterflies, Ornithoptera, the largest butterflies of the world, together forming a small genus in the butterfly family Papilionidae. The wings of these butterflies are marked by strongly coloured patches. The colours are caused by specially structured wing scales, which act as a chirped multilayer reflector, but the scales also contain papiliochrome pigments, which act as a spectral filter. The combined structural and pigmentary effects tune the coloration of the wing scales. The tuned colours are presumably important for mate recognition and signalling. By applying electron microscopy, (micro-)spectrophotometry and scatterometry we found that the various mechanisms of scale coloration of the different birdwing species strongly correlate with the taxonomical distribution of Ornithoptera species. PMID:26446560

A practical and objective approach to scar colour assessment.

PubMed

Hallam, M J; McNaught, K; Thomas, A N; Nduka, C

2013-10-01

Scarring is a significant clinical problem following dermal injury. However, scars are not a single describable entity and huge phenotypic variability is evident. Quantitative, reproducible inter-observer scar assessment is essential to monitor wound healing and the effect of scar treatments. Scar colour, reflecting the biological processes occurring within a scar, is integral to any assessment. The objective of this study was to analyse scar colour using the non-invasive Eykona® Wound Measurement System (the System) as compared against the Manchester Scar Scale (MSS). Three dimensional images of 43 surgical scars were acquired post-operatively from 35 patients at 3-6 months and the colour difference between the scar and surrounding skin was calculated (giving ΔLab values). The colourimetric results were then compared against subjective MSS gradings. A significant difference in ΔLab values between MSS gradings of "slight mismatch" and "obvious mismatch" (p<0.025) and between "obvious mismatch" and "gross mismatch" (p<0.05) were noted. The System creates objective, reproducible data, without the need for any specialist expertise and compares favourably with the MSS. Greater scar numbers are required to further clinically validate this device--however, with this potential to calculate scar length, width, volume and other characteristics, it could provide a complete, objective, quantitative record of scarring throughout the wound-healing process. Copyright © 2013 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Metrological characterization methods for confocal chromatic line sensors and optical topography sensors

NASA Astrophysics Data System (ADS)

Seppä, Jeremias; Niemelä, Karri; Lassila, Antti

2018-05-01

The increasing use of chromatic confocal technology for, e.g. fast, in-line optical topography, and measuring thickness, roughness and profiles implies a need for the characterization of various aspects of the sensors. Single-point, line and matrix versions of chromatic confocal technology, encoding depth information into wavelength, have been developed. Of these, line sensors are particularly suitable for in-line process measurement. Metrological characterization and development of practical methods for calibration and checking is needed for new optical methods and devices. Compared to, e.g. tactile methods, optical topography measurement techniques have limitations related to light wavelength and coherence, optical properties of the sample including reflectivity, specularity, roughness and colour, and definition of optical versus mechanical surfaces. In this work, metrological characterization methods for optical line sensors were developed for scale magnification and linearity, sensitivity to sample properties, and dynamic characteristics. An accurate depth scale calibration method using a single prototype groove depth sample was developed for a line sensor and validated with laser-interferometric sample tracking, attaining (sub)micrometre level or better than 0.1% scale accuracy. Furthermore, the effect of different surfaces and materials on the measurement and depth scale was studied, in particular slope angle, specularity and colour. In addition, dynamic performance, noise, lateral scale and resolution were measured using the developed methods. In the case of the LCI1200 sensor used in this study, which has a 11.3 mm  ×  2.8 mm measurement range, the instrument depth scale was found to depend only minimally on sample colour, whereas measuring steeply sloped specular surfaces in the peripheral measurement area, in the worst case, caused a somewhat larger relative sample-dependent change (1%) in scale.

Quantifying Variability of Avian Colours: Are Signalling Traits More Variable?

PubMed Central

Delhey, Kaspar; Peters, Anne

2008-01-01

Background Increased variability in sexually selected ornaments, a key assumption of evolutionary theory, is thought to be maintained through condition-dependence. Condition-dependent handicap models of sexual selection predict that (a) sexually selected traits show amplified variability compared to equivalent non-sexually selected traits, and since males are usually the sexually selected sex, that (b) males are more variable than females, and (c) sexually dimorphic traits more variable than monomorphic ones. So far these predictions have only been tested for metric traits. Surprisingly, they have not been examined for bright coloration, one of the most prominent sexual traits. This omission stems from computational difficulties: different types of colours are quantified on different scales precluding the use of coefficients of variation. Methodology/Principal Findings Based on physiological models of avian colour vision we develop an index to quantify the degree of discriminable colour variation as it can be perceived by conspecifics. A comparison of variability in ornamental and non-ornamental colours in six bird species confirmed (a) that those coloured patches that are sexually selected or act as indicators of quality show increased chromatic variability. However, we found no support for (b) that males generally show higher levels of variability than females, or (c) that sexual dichromatism per se is associated with increased variability. Conclusions/Significance We show that it is currently possible to realistically estimate variability of animal colours as perceived by them, something difficult to achieve with other traits. Increased variability of known sexually-selected/quality-indicating colours in the studied species, provides support to the predictions borne from sexual selection theory but the lack of increased overall variability in males or dimorphic colours in general indicates that sexual differences might not always be shaped by similar selective forces. PMID:18301766

Coloration principles of nymphaline butterflies - thin films, melanin, ommochromes and wing scale stacking.

PubMed

Stavenga, Doekele G; Leertouwer, Hein L; Wilts, Bodo D

2014-06-15

The coloration of the common butterflies Aglais urticae (small tortoiseshell), Aglais io (peacock) and Vanessa atalanta (red admiral), belonging to the butterfly subfamily Nymphalinae, is due to the species-specific patterning of differently coloured scales on their wings. We investigated the scales' structural and pigmentary properties by applying scanning electron microscopy, (micro)spectrophotometry and imaging scatterometry. The anatomy of the wing scales appears to be basically identical, with an approximately flat lower lamina connected by trabeculae to a highly structured upper lamina, which consists of an array of longitudinal, parallel ridges and transversal crossribs. Isolated scales observed at the abwing (upper) side are blue, yellow, orange, red, brown or black, depending on their pigmentation. The yellow, orange and red scales contain various amounts of 3-OH-kynurenine and ommochrome pigment, black scales contain a high density of melanin, and blue scales have a minor amount of melanin pigment. Observing the scales from their adwing (lower) side always revealed a structural colour, which is blue in the case of blue, red and black scales, but orange for orange scales. The structural colours are created by the lower lamina, which acts as an optical thin film. Its reflectance spectrum, crucially determined by the lamina thickness, appears to be well tuned to the scales' pigmentary spectrum. The colours observed locally on the wing are also due to the degree of scale stacking. Thin films, tuned pigments and combinations of stacked scales together determine the wing coloration of nymphaline butterflies. © 2014. Published by The Company of Biologists Ltd.

Comparing colour discrimination and proofreading performance under compact fluorescent and halogen lamp lighting.

PubMed

Mayr, Susanne; Köpper, Maja; Buchner, Axel

2013-01-01

Legislation in many countries has banned inefficient household lighting. Consequently, classic incandescent lamps have to be replaced by more efficient alternatives such as halogen and compact fluorescent lamps (CFL). Alternatives differ in their spectral power distributions, implying colour-rendering differences. Participants performed a colour discrimination task - the Farnsworth-Munsell 100 Hue Test--and a proofreading task under CFL or halogen lighting of comparable correlated colour temperatures at low (70 lx) or high (800 lx) illuminance. Illuminance positively affected colour discrimination and proofreading performance, whereas the light source was only relevant for colour discrimination. Discrimination was impaired with CFL lighting. There were no differences between light sources in terms of self-reported physical discomfort and mood state, but the majority of the participants correctly judged halogen lighting to be more appropriate for discriminating colours. The findings hint at the colour-rendering deficiencies associated with energy-efficient CFLs. In order to compare performance under energy-efficient alternatives of classic incandescent lighting, colour discrimination and proofreading performance was compared under CFL and halogen lighting. Colour discrimination was impaired under CFLs, which hints at the practical drawbacks associated with the reduced colour-rendering properties of energy-efficient CFLs.

Impact of nurses clothing on anxiety of hospitalised children.

PubMed

Roohafza, Hamidreza; Pirnia, Afsaneh; Sadeghi, Masoumeh; Toghianifar, Nafiseh; Talaei, Mohammad; Ashrafi, Mahmood

2009-07-01

To investigate anxiety levels in two groups of children exposed to nurses with white vs. coloured clothing in a university hospital in Iran. Hospitalisation causes anxiety in children and it is documented that nurses have an important role in alleviating children's distress and anxiety. Nurses characteristics, including their clothing is a factor that affects quality of care through child-nurse relationship. Clinical trial. Children (n = 92) aged 7-15 years old hospitalised for 3-5 days in paediatric surgery ward were exposed to nurses in white or coloured clothing. Children's anxiety was assessed on admission and at discharge using Revised Children's Manifest Anxiety Scale. Children exposed to white nursing uniforms showed higher anxiety levels compared with children exposed to coloured nursing clothing (p < or = 0.05). Besides coloured nursing clothing, female sex, age >11 years old (guidance school) and living in families with more than four members were predictors of lower global anxiety scores. Providing a child-friendly environment through colourful nursing clothing can promote nurses' relationship with hospitalised children. This can satisfy children's expectations of the nursing care and alleviates the need for meeting ideals of nursing care through wearing a white nursing uniform provided that standards of nursing care are favoured. Using colourful nursing clothing in paediatric wards reduces anxiety as a psychological parameter which delays improvement and provides a child-friendly environment that helps promotion of quality of nursing care.

Colour Measurements and Modeling

NASA Astrophysics Data System (ADS)

Jha, Shyam N.

The most common property to measure quality of any material is its appearance. Appearance includes colour, shape, size and surface conditions. The analysis of colour is especially an important consideration when determining the efficacy of variety of postharvest treatments. Consumers can easily be influenced by preconceived ideas of how a particular fruit or vegetable or a processed food should appear, and marketers often attempt to improve upon what nature has painted. Recently colour measurements have also been used as quality parameters and indicator of some inner constituents of the material. In spite of the significance of colour in food industries, many continue to analyze it inadequately. This chapter deals with theory of colour, colour scales and its measurement, sampling techniques, and modeling of colour values for correlating them with some internal quality parameters of selected fruits.

Pterin pigments amplify iridescent ultraviolet signal in males of the orange sulphur butterfly, Colias eurytheme

PubMed Central

Rutowski, R.L; Macedonia, J.M; Morehouse, N; Taylor-Taft, L

2005-01-01

Animal colouration is typically the product of nanostructures that reflect or scatter light and pigments that absorb it. The interplay between these colour-producing mechanisms may influence the efficacy and potential information content of colour signals, but this notion has received little empirical attention. Wing scales in the male orange sulphur butterfly (Colias eurytheme) possess ridges with lamellae that produce a brilliant iridescent ultraviolet (UV) reflectance via thin-film interference. Curiously, these same scales contain pterin pigments that strongly absorb wavelengths below 550 nm. Given that male UV reflectance functions as a sexual signal in C. eurytheme, it is paradoxical that pigments in the wing scales are highly UV absorbing. We present spectrophotometric analyses of the wings before and after pterin removal that show that pterins both depress the amplitude of UV iridescence and suppress a diffuse UV reflectance that emanates from the scales. This latter effect enhances the directionality and spectral purity of the iridescence, and increases the signal's chromaticity and potential signal content. Our findings also suggest that pterins amplify the contrast between iridescent UV reflectance and scale background colour as a male's wings move during flight. PMID:16191648

Pterin pigments amplify iridescent ultraviolet signal in males of the orange sulphur butterfly, Colias eurytheme.

PubMed

Rutowski, R L; Macedonia, J M; Morehouse, N; Taylor-Taft, L

2005-11-07

Animal colouration is typically the product of nanostructures that reflect or scatter light and pigments that absorb it. The interplay between these colour-producing mechanisms may influence the efficacy and potential information content of colour signals, but this notion has received little empirical attention. Wing scales in the male orange sulphur butterfly (Colias eurytheme) possess ridges with lamellae that produce a brilliant iridescent ultraviolet (UV) reflectance via thin-film interference. Curiously, these same scales contain pterin pigments that strongly absorb wavelengths below 550 nm. Given that male UV reflectance functions as a sexual signal in C. eurytheme, it is paradoxical that pigments in the wing scales are highly UV absorbing. We present spectrophotometric analyses of the wings before and after pterin removal that show that pterins both depress the amplitude of UV iridescence and suppress a diffuse UV reflectance that emanates from the scales. This latter effect enhances the directionality and spectral purity of the iridescence, and increases the signal's chromaticity and potential signal content. Our findings also suggest that pterins amplify the contrast between iridescent UV reflectance and scale background colour as a male's wings move during flight.

Whorfian effects on colour memory are not reliable.

PubMed

Wright, Oliver; Davies, Ian R L; Franklin, Anna

2015-01-01

The Whorfian hypothesis suggests that differences between languages cause differences in cognitive processes. Support for this idea comes from studies that find that patterns of colour memory errors made by speakers of different languages align with differences in colour lexicons. The current study provides a large-scale investigation of the relationship between colour language and colour memory, adopting a cross-linguistic and developmental approach. Colour memory on a delayed matching-to-sample (XAB) task was investigated in 2 language groups with differing colour lexicons, for 3 developmental stages and 2 regions of colour space. Analyses used a Bayesian technique to provide simultaneous assessment of two competing hypotheses (H1-Whorfian effect present, H0-Whorfian effect absent). Results of the analyses consistently favoured H0. The findings suggest that Whorfian effects on colour memory are not reliable and that the importance of such effects should not be overestimated.

Potential of powdered activated mustard cake for decolorising raw sugar.

PubMed

Singh, Kaman; Bharose, Ram; Verma, Sudhir Kumar; Singh, Vimalesh Kumar

2013-01-15

Carbon decolorisation has become customary in the food processing industries; however, it is not economical. Extensive research has therefore been directed towards investigating potential substitutes for commercial activated carbons which might have the advantage of offering an effective, lower-cost replacement for existing bone char or coal-based granular activated carbon (GAC). The physical (bulk density and hardness), chemical (pH and mineral content) and adsorption characteristics (iodine test, molasses test and raw sugar decolorisation efficiency) of powdered activated mustard cake (PAMC) made from de-oiled mustard cake were determined and compared to commercial adsorbents. Although the colour removal efficiency of the PAMC is lower than that of commercial materials, it is cost effective and eco-friendly compared to the existing decolorisation/refining processes. To reduce the load on GAC/activated carbon/charcoal, PAMC could be used on an industrial scale. A decolorisation mechanism has been postulated on the basis of oxygen surface functionalities and surface charge of the PAMC and, accordingly, charge transfer interaction seems to be responsible for the decolorisation mechanism. In addition, a complex interplay of electrostatics and dispersive interaction seem to be involved during the decolorisation process. A low-cost agricultural waste product in the form of de-oiled mustard cake was converted to an efficient adsorbent, PAMC, for use in decolorising raw as well as coloured sugar solutions. The physical, chemical, adsorption characteristics and raw sugar decolorisation efficiency of PAMC were determined and compared to those of commercial adsorbents. The colour removal efficiency of the PAMC is lower than that of commercial materials but it is cost effective and eco-friendly as compared to existing decolorisation/refining processes. The availability of the raw material for the production of PAMC further demands its use on an industrial scale. Copyright © 2012 Society of Chemical Industry.

Biomimicry of optical microstructures of Papilio palinurus

NASA Astrophysics Data System (ADS)

Crne, Matija; Sharma, Vivek; Blair, John; Park, Jung Ok; Summers, Christopher J.; Srinivasarao, Mohan

2011-01-01

The brilliant coloration of animals in nature is sometimes based on their structure rather than on pigments. The green colour on the wings of a butterfly Papilio palinurus originates from the hierarchical microstructure of individual wing scales that are tiled on the wing. The hierarchical structure gives rise to two coloured reflections of visible light, blue and yellow which when additively mixed, produce the perception of green colour on the wing scales. We used breath figure templated assembly as the starting point for the structure and, combining it with atomic layer deposition for the multilayers necessary for the production of interference colors, we have faithfully mimicked the structure and the optical effects found on the wing scale of the butterfly Papilio palinurus.

The colour of fitness: plumage coloration and lifetime reproductive success in the tawny owl

PubMed Central

Brommer, Jon E; Ahola, Kari; Karstinen, Teuvo

2005-01-01

We studied variation in plumage colour and life history in a population of tawny owls (Strix aluco) in southern Finland, using 26 years of data on individually marked male and female owls. Colour was scored on a semi-continuous scale from pale grey to reddish brown. Colour scoring was repeatable and showed a bimodal distribution (grey and brown morph) in both sexes. During the study period, colour composition was stable in the study population in both sexes. The sexes did not mate assortatively with respect to their colour. Colour was a highly heritable trait and was under selection. Grey-coloured male and female owls had a higher lifetime production of fledglings, and grey-coloured male (but not female) owls produced more recruits during their lifetime than brown individuals. Selection on colour was mediated through viability selection and not through fecundity selection. Our results reveal remarkably strong selection on a genetically determined phenotypic trait. PMID:16024349

The impacts of prescribed moorland burning on water colour and dissolved organic carbon: a critical synthesis.

PubMed

Holden, J; Chapman, P J; Palmer, S M; Kay, P; Grayson, R

2012-06-30

Discolouration of natural surface waters due to the humic component of dissolved organic carbon (DOC) is a costly problem for water supply companies. This paper reviews what is known about the impacts of prescribed moorland vegetation burning on water colour. Relevant research has taken place at three scales: laboratory experiments on peat cores, plot scale sampling of soil waters and catchment scale sampling of stream waters. While laboratory studies suggest burning increases colour production, the evidence from catchment and plot studies is contradictory. Plot studies suggest colour production may decrease or remain unchanged following burning although there is evidence for some transient changes. Catchment studies suggest prescribed moorland burning causes stream water colour to increase, although in most cases the evidence is not clear cut since most studies could not clearly disentangle the effects of burning from those of vegetation cover. The differences in findings between plot and catchment studies may be explained by: i) the short-term nature of some studies which do not measure long-term response and recovery times to burning; ii) the lack of colour measurements from shallow soil depths which contribute more to streamflow than soil water from deeper in the peat; and iii) the possibility of hydrological interactions occurring between different experimental plots at some sites. Additionally, the increase in recent patch burning in some catchments that has been statistically attributed by some authors to increases in stream water colour cannot be reconciled with theoretical calculations. When dilution with waters derived from other parts of the catchment are taken into account, large values of colour have to be theoretically derived from those recently burnt areas that occupy a small proportion of the catchment area in order to balance the change in stream water colour observed in recent years. Therefore, much further process-based work is required to properly investigate whether prescribed vegetation burning is a direct driver of enhanced colour and DOC in upland streams, rivers and lakes. Copyright © 2012 Elsevier Ltd. All rights reserved.

Fruit over sunbed: carotenoid skin colouration is found more attractive than melanin colouration.

PubMed

Lefevre, Carmen E; Perrett, David I

2015-01-01

Skin colouration appears to play a pivotal part in facial attractiveness. Skin yellowness contributes to an attractive appearance and is influenced both by dietary carotenoids and by melanin. While both increased carotenoid colouration and increased melanin colouration enhance apparent health in Caucasian faces by increasing skin yellowness, it remains unclear, firstly, whether both pigments contribute to attractiveness judgements, secondly, whether one pigment is clearly preferred over the other, and thirdly, whether these effects depend on the sex of the face. Here, in three studies, we examine these questions using controlled facial stimuli transformed to be either high or low in (a) carotenoid colouration, or (b) melanin colouration. We show, firstly, that both increased carotenoid colouration and increased melanin colouration are found attractive compared to lower levels of these pigments. Secondly, we show that carotenoid colouration is consistently preferred over melanin colouration when levels of colouration are matched. In addition, we find an effect of the sex of stimuli with stronger preferences for carotenoids over melanin in female compared to male faces, irrespective of the sex of the observer. These results are interpreted as reflecting preferences for sex-typical skin colouration: men have darker skin than women and high melanization in male faces may further enhance this masculine trait, thus carotenoid colouration is not less desirable, but melanin colouration is relatively more desirable in males compared to females. Taken together, our findings provide further support for a carotenoid-linked health-signalling system that is highly important in mate choice.

Most and Least Preferred Colours Differ According to Object Context: New Insights from an Unrestricted Colour Range

PubMed Central

Jonauskaite, Domicele; Mohr, Christine; Antonietti, Jean-Philippe; Spiers, Peter M.; Althaus, Betty; Anil, Selin; Dael, Nele

2016-01-01

Humans like some colours and dislike others, but which particular colours and why remains to be understood. Empirical studies on colour preferences generally targeted most preferred colours, but rarely least preferred (disliked) colours. In addition, findings are often based on general colour preferences leaving open the question whether results generalise to specific objects. Here, 88 participants selected the colours they preferred most and least for three context conditions (general, interior walls, t-shirt) using a high-precision colour picker. Participants also indicated whether they associated their colour choice to a valenced object or concept. The chosen colours varied widely between individuals and contexts and so did the reasons for their choices. Consistent patterns also emerged, as most preferred colours in general were more chromatic, while for walls they were lighter and for t-shirts they were darker and less chromatic compared to least preferred colours. This meant that general colour preferences could not explain object specific colour preferences. Measures of the selection process further revealed that, compared to most preferred colours, least preferred colours were chosen more quickly and were less often linked to valenced objects or concepts. The high intra- and inter-individual variability in this and previous reports furthers our understanding that colour preferences are determined by subjective experiences and that most and least preferred colours are not processed equally. PMID:27022909

Most and Least Preferred Colours Differ According to Object Context: New Insights from an Unrestricted Colour Range.

PubMed

Jonauskaite, Domicele; Mohr, Christine; Antonietti, Jean-Philippe; Spiers, Peter M; Althaus, Betty; Anil, Selin; Dael, Nele

2016-01-01

Humans like some colours and dislike others, but which particular colours and why remains to be understood. Empirical studies on colour preferences generally targeted most preferred colours, but rarely least preferred (disliked) colours. In addition, findings are often based on general colour preferences leaving open the question whether results generalise to specific objects. Here, 88 participants selected the colours they preferred most and least for three context conditions (general, interior walls, t-shirt) using a high-precision colour picker. Participants also indicated whether they associated their colour choice to a valenced object or concept. The chosen colours varied widely between individuals and contexts and so did the reasons for their choices. Consistent patterns also emerged, as most preferred colours in general were more chromatic, while for walls they were lighter and for t-shirts they were darker and less chromatic compared to least preferred colours. This meant that general colour preferences could not explain object specific colour preferences. Measures of the selection process further revealed that, compared to most preferred colours, least preferred colours were chosen more quickly and were less often linked to valenced objects or concepts. The high intra- and inter-individual variability in this and previous reports furthers our understanding that colour preferences are determined by subjective experiences and that most and least preferred colours are not processed equally.

The effect of high correlated colour temperature office lighting on employee wellbeing and work performance.

PubMed

Mills, Peter R; Tomkins, Susannah C; Schlangen, Luc J M

2007-01-11

The effects of lighting on the human circadian system are well-established. The recent discovery of 'non-visual' retinal receptors has confirmed an anatomical basis for the non-image forming, biological effects of light and has stimulated interest in the use of light to enhance wellbeing in the corporate setting. A prospective controlled intervention study was conducted within a shift-working call centre to investigate the effect of newly developed fluorescent light sources with a high correlated colour temperature (17000 K) upon the wellbeing, functioning and work performance of employees. Five items of the SF-36 questionnaire and a modification of the Columbia Jet Lag scale, were used to evaluate employees on two different floors of the call centre between February and May 2005. Questionnaire completion occurred at baseline and after a three month intervention period, during which time one floor was exposed to new high correlated colour temperature lighting and the other remained exposed to usual office lighting. Two sided t-tests with Bonferroni correction for type I errors were used to compare the characteristics of the two groups at baseline and to evaluate changes in the intervention and control groups over the period of the study. Individuals in the intervention arm of the study showed a significant improvement in self-reported ability to concentrate at study end as compared to those within the control arm (p < 0.05). The mean individual score on a 5 point Likert scale improved by 36.8% in the intervention group, compared with only 1.7% in the control group. The majority of this improvement occurred within the first 7 weeks of the 14 week study. Substantial within group improvements were observed in the intervention group in the areas of fatigue (26.9%), alertness (28.2%), daytime sleepiness (31%) and work performance (19.4%), as assessed by the modified Columbia Scale, and in the areas of vitality (28.4%) and mental health (13.9%), as assessed by the SF-36 over the study period. High correlated colour temperature fluorescent lights could provide a useful intervention to improve wellbeing and productivity in the corporate setting, although further work is necessary in quantifying the magnitude of likely benefits.

Seeing red primes tomato: evidence for comparable priming from colour and colour name primes to semantically related word targets.

PubMed

Nijboer, Tanja C W; van Zandvoort, Martine J E; de Haan, Edward H F

2006-12-01

There is ample evidence that an independent processing stream exists that subserves the perception and appreciation of colour. Neurophysiological research has identified separate brain mechanisms for the processing of wavelength and colour, and neuropsychological studies have revealed selective colour disorders, such as achromatopsia, colour agnosia, and colour anomia. The aim of the present study is to investigate whether the perception of colour may, despite its independent processing, influence other cognitive functions. Specifically, we investigate the possibility that the perception of a colour influences higher order processes such as the activation of semantically related concepts. We designed an associative priming task involving a colour prime (e.g. a red patch or the word RED) and a lexical decision response to a semantically related ('tomato' vs. 'timato') or unrelated ('grass' vs. 'griss') word target. The results of this experiment indicate that there is comparable facilitation of accessing colour-related semantics through the perception of a colour or the reading of a colour name. This suggests that colour has a direct effect on higher order level, cognitive processing. These results are discussed in terms of current models of colour processing.

Oxidation of edible animal fats. Comparison of the performance of different quantification methods and of a proposed new semi-objective colour scale-based method.

PubMed

Méndez-Cid, Francisco J; Lorenzo, José M; Martínez, Sidonia; Carballo, Javier

2017-02-15

The agreement among the results determined for the main parameters used in the evaluation of the fat auto-oxidation was investigated in animal fats (butter fat, subcutaneous pig back-fat and subcutaneous ham fat). Also, graduated colour scales representing the colour change during storage/ripening were developed for the three types of fat, and the values read in these scales were correlated with the values observed for the different parameters indicating fat oxidation. In general good correlation among the values of the different parameters was observed (e.g. TBA value correlated with the peroxide value: r=0.466 for butter and r=0.898 for back-fat). A reasonable correlation was observed between the values read in the developed colour scales and the values for the other parameters determined (e.g. values of r=0.320 and r=0.793 with peroxide value for butter and back-fat, respectively, and of r=0.767 and r=0.498 with TBA value for back-fat and ham fat, respectively). Copyright © 2016 Elsevier Ltd. All rights reserved.

Use of Tectonagrandis Leaf Extract in Colouring Silk Cloth Material Based on pH and Mordant Variations

NASA Astrophysics Data System (ADS)

Rosyida, A.; Suranto

2018-03-01

One of the very potential use of plant natural colour in the industrial activities was Anthocyanin. This substance contains in a number on plant organs such as Tectona Grandis (Fabaceae) particularly in their leaf materials. In order to get this secondary metabolism, the aim of this research was to find out the optimum condition of mordant and the pH combination in producing natural colour of Tectonagrandis leaf extract. To get this chemical substance, 1 kilogram of young leaves were cut into smaller size and soaked in 7 litre of H2O for 12 hour9. The solution was then boiled for 15 minutes. To get the best colour, variations of pH (5, 7 and 9) respectivelly were applied. The results showed that purple to redness were resulted when pH 5 and no additional mordant was added. Conversly the greyness to black, were produced when ferrosulphate were added. When the addition of alum was made the redies purple will appear. These colours were considered quite good quality under examination of grey and staining scales (4-5) after treated by both wet and dry rubbing methods. The test for wash fastness resulted in sufficiently good value of color change (value of 3 on Grey Scale standard), while test for staining demonstrated good staining (value of 4 on Staining Scale standard). This early finding was quite promosing to be applied in the near future in providing natural colours for industrial purposes.

Spatial and temporal aspects of chromatic adaptation and their functional significance for colour constancy.

PubMed

Werner, Annette

2014-11-01

Illumination in natural scenes changes at multiple temporal and spatial scales: slow changes in global illumination occur in the course of a day, and we encounter fast and localised illumination changes when visually exploring the non-uniform light field of three-dimensional scenes; in addition, very long-term chromatic variations may come from the environment, like for example seasonal changes. In this context, I consider the temporal and spatial properties of chromatic adaptation and discuss their functional significance for colour constancy in three-dimensional scenes. A process of fast spatial tuning in chromatic adaptation is proposed as a possible sensory mechanism for linking colour constancy to the spatial structure of a scene. The observed middlewavelength selectivity of this process is particularly suitable for adaptation to the mean chromaticity and the compensation of interreflections in natural scenes. Two types of sensory colour constancy are distinguished, based on the functional differences of their temporal and spatial scales: a slow type, operating at a global scale for the compensation of the ambient illumination; and a fast colour constancy, which is locally restricted and well suited to compensate region-specific variations in the light field of three dimensional scenes. Copyright © 2014 Elsevier B.V. All rights reserved.

Mountain pine beetle detection and monitoring: evaluation of airborne imagery

NASA Astrophysics Data System (ADS)

Roberts, A.; Bone, C.; Dragicevic, S.; Ettya, A.; Northrup, J.; Reich, R.

2007-10-01

The processing and evaluation of digital airborne imagery for detection, monitoring and modeling of mountain pine beetle (MPB) infestations is evaluated. The most efficient and reliable remote sensing strategy for identification and mapping of infestation stages ("current" to "red" to "grey" attack) of MPB in lodgepole pine forests is determined for the most practical and cost effective procedures. This research was planned to specifically enhance knowledge by determining the remote sensing imaging systems and analytical procedures that optimize resource management for this critical forest health problem. Within the context of this study, airborne remote sensing of forest environments for forest health determinations (MPB) is most suitably undertaken using multispectral digitally converted imagery (aerial photography) at scales of 1:8000 for early detection of current MPB attack and 1:16000 for mapping and sequential monitoring of red and grey attack. Digital conversion should be undertaken at 10 to 16 microns for B&W multispectral imagery and 16 to 24 microns for colour and colour infrared imagery. From an "operational" perspective, the use of twin mapping-cameras with colour and B&W or colour infrared film will provide the best approximation of multispectral digital imagery with near comparable performance in a competitive private sector context (open bidding).

From spectral information to animal colour vision: experiments and concepts.

PubMed

Kelber, Almut; Osorio, Daniel

2010-06-07

Many animals use the spectral distribution of light to guide behaviour, but whether they have colour vision has been debated for over a century. Our strong subjective experience of colour and the fact that human vision is the paradigm for colour science inevitably raises the question of how we compare with other species. This article outlines four grades of 'colour vision' that can be related to the behavioural uses of spectral information, and perhaps to the underlying mechanisms. In the first, even without an (image-forming) eye, simple organisms can compare photoreceptor signals to locate a desired light environment. At the next grade, chromatic mechanisms along with spatial vision guide innate preferences for objects such as food or mates; this is sometimes described as wavelength-specific behaviour. Here, we compare the capabilities of di- and trichromatic vision, and ask why some animals have more than three spectral types of receptors. Behaviours guided by innate preferences are then distinguished from a grade that allows learning, in part because the ability to learn an arbitrary colour is evidence for a neural representation of colour. The fourth grade concerns colour appearance rather than colour difference: for instance, the distinction between hue and saturation, and colour categorization. These higher-level phenomena are essential to human colour perception but poorly known in animals, and we suggest how they can be studied. Finally, we observe that awareness of colour and colour qualia cannot be easily tested in animals.

Exploring structural colour in uni- and multi-coloured butterfly wings and Ag+ uptake by scales

NASA Astrophysics Data System (ADS)

Aideo, Swati N.; Haloi, Rajib; Mohanta, Dambarudhar

2017-09-01

We discuss the origin of the structural colour of different butterfly wings in the light of the typical built-in microstructural arrangement of scales that are comprised of chitin-melanin layer and air-gaps. Three specimens of butterfly wings namely, Papilio Liomedon (black), Catopsilia Pyranthe (light green) and Vanessa Cardui (multi-coloured) were chosen and diffuse reflectance characteristics have been aquired for normal incidence of p-polarized light. Moreover, the time-dependent uptake of Ag+ into scales has led to swelling and spread of the chitinous ridges and ribs, with revelation of micro-beads in Catopsilia Pyranthe specimen. The reduction of the number of air-gaps between any two parallel ridges is attributed to the merging of adjacent gaps possessing a common boundary. The availability of Ag at the centre of a chosen ridge, for every wing type, follows an exponential growing trend, ∼e0.36t . Precise inclusion of nanoscale metals into natural photonic systems would provide new insight, while applying principles of photonics and plasmonics simultaneously.

[The experience with spectrophotometric method for determination of teeth colour changes in the process of tooth whitening by different systems].

PubMed

Porkhun, T V; Iakoviuk, I A

2006-01-01

The use of spectrophotometer VITA Easyshade is described as an objective method of definition of color of a teeth alongside with a standard scale VITA. Results of assessment of efficiency, safety, a comparative estimation of domestic bleaching Aquafresh and LumaArch systems are given.

[Chemical and sensory characterization of tea (Thea sinensis) consumed in Chile].

PubMed

Wittig de Penna, Emma; José Zúñiga, María; Fuenzalida, Regina; López-Planes, Reinaldo

2005-03-01

By means of descriptive analysis four varieties of tea (Thea sinensis) were assesed: Argentinean OP (orange pekoe) tea (black), Brazilian OP tea (black), Ceylan OP tea (black) and Darjeeling OP tea (green). The appearance of dry tea leaves were qualitatively characterized comparing with dry leaves standard. The attributes: colour, form, regularity of the leaves, fibre and stem cutting were evaluated The differences obtained were related to the differences produced by the effect of the fermentation process. Flavour and aroma descriptors of the tea liqueur were generated by a trained panel. Colour and astringency were evaluated in comparison with qualified standards using non structured linear scales. In order to relate the sensory analysis and the chemical composition for the different varieties of tea, following determinations were made: chemical moisture, dry material, aqueous extract, tannin and caffeine. Through multifactor regression analysis the equations in relation to the following chemical parameters were determined. Dry material, aqueous extract and tannins for colour and moisture, dry material and aqueous extract for astringency, respectively. Statistical analysis through ANOVA (3 variation sources: samples, judges and replications) showed for samples four significant different groups for astringency and three different groups for colour. No significant differences between judges or repetitions were found. By multifactor regression analysis of both, colour and astringency, on their dependence of chemist results were calculated in order to asses the corresponding equations.

Snake velvet black: Hierarchical micro- and nanostructure enhances dark colouration in Bitis rhinoceros

NASA Astrophysics Data System (ADS)

Spinner, Marlene; Kovalev, Alexander; Gorb, Stanislav N.; Westhoff, Guido

2013-05-01

The West African Gaboon viper (Bitis rhinoceros) is a master of camouflage due to its colouration pattern. Its skin is geometrically patterned and features black spots that purport an exceptional spatial depth due to their velvety surface texture. Our study shades light on micromorphology, optical characteristics and principles behind such a velvet black appearance. We revealed a unique hierarchical pattern of leaf-like microstructures striated with nanoridges on the snake scales that coincides with the distribution of black colouration. Velvet black sites demonstrate four times lower reflectance and higher absorbance than other scales in the UV - near IR spectral range. The combination of surface structures impeding reflectance and absorbing dark pigments, deposited in the skin material, provides reflecting less than 11% of the light reflected by a polytetrafluoroethylene diffuse reflectance standard in any direction. A view-angle independent black structural colour in snakes is reported here for the first time.

Bio-inspired colorimetric film based on hygroscopic coloration of longhorn beetles (Tmesisternus isabellae)

PubMed Central

Seo, Han-bok; Lee, Seung-Yop

2017-01-01

Structure-dependent colour is caused by the interaction of light with photonic crystal structures rather than pigments. The elytra of longhorn beetles Tmesisternus isabellae appear to be iridescent green in a dry state and turn to red when exposed to humidity. Based on the hygroscopic colouration of the longhorn beetle, we have developed centimeter-scale colorimetric opal films using a novel self-assembly method. The micro-channel assisted assembly technique adopts both natural evaporation and rotational forced drying, enhancing the surface binding of silica particles and the packing density by reducing the lattice constant and structural defects. The fabricated large-scale photonic film changes its structural colour from green to red when exposed to water vapour, similarly to the colorimetric feature of the longhorn beetle. The humidity-dependent colour change of the opal film is shown to be reversible and durable over five-hundred cycles of wetting and drying. PMID:28322307

Bio-inspired colorimetric film based on hygroscopic coloration of longhorn beetles (Tmesisternus isabellae)

NASA Astrophysics Data System (ADS)

Seo, Han-Bok; Lee, Seung-Yop

2017-03-01

Structure-dependent colour is caused by the interaction of light with photonic crystal structures rather than pigments. The elytra of longhorn beetles Tmesisternus isabellae appear to be iridescent green in a dry state and turn to red when exposed to humidity. Based on the hygroscopic colouration of the longhorn beetle, we have developed centimeter-scale colorimetric opal films using a novel self-assembly method. The micro-channel assisted assembly technique adopts both natural evaporation and rotational forced drying, enhancing the surface binding of silica particles and the packing density by reducing the lattice constant and structural defects. The fabricated large-scale photonic film changes its structural colour from green to red when exposed to water vapour, similarly to the colorimetric feature of the longhorn beetle. The humidity-dependent colour change of the opal film is shown to be reversible and durable over five-hundred cycles of wetting and drying.

Snake velvet black: hierarchical micro- and nanostructure enhances dark colouration in Bitis rhinoceros.

PubMed

Spinner, Marlene; Kovalev, Alexander; Gorb, Stanislav N; Westhoff, Guido

2013-01-01

The West African Gaboon viper (Bitis rhinoceros) is a master of camouflage due to its colouration pattern. Its skin is geometrically patterned and features black spots that purport an exceptional spatial depth due to their velvety surface texture. Our study shades light on micromorphology, optical characteristics and principles behind such a velvet black appearance. We revealed a unique hierarchical pattern of leaf-like microstructures striated with nanoridges on the snake scales that coincides with the distribution of black colouration. Velvet black sites demonstrate four times lower reflectance and higher absorbance than other scales in the UV-near IR spectral range. The combination of surface structures impeding reflectance and absorbing dark pigments, deposited in the skin material, provides reflecting less than 11% of the light reflected by a polytetrafluoroethylene diffuse reflectance standard in any direction. A view-angle independent black structural colour in snakes is reported here for the first time.

Measurements and modelling of the influence of dentine colour and enamel on tooth colour.

PubMed

Battersby, Paul D; Battersby, Stephen J

2015-03-01

We provide a quantitative predictive model for the extent to which coloured dentine, visible through the enamel, contributes to tooth colour. Our model uses (L(*),a(*),b(*)) measurements rather than spectral measurements. We have used a model system, composed of a slice of bovine enamel placed on top of coloured paper. We have measured the colour of the enamel-paper combination, as an analogue for a tooth, and have related this to the colour of the paper, as an analogue for dentine. By changing the paper colour, we have been able to explore how the colour of dentine determines tooth colour, according to our model system. We have also compared hydrated and desiccated samples. In qualitative terms, superimposing the enamel on top of the paper increases the "lightness" for all colours tested except white while simultaneously reducing the chromaticity, a measure of the extent to which the colour differs from grey. Desiccated enamel is much more effective at increasing the lightness and reducing the chromaticity than hydrated enamel. Quantitatively, our measurements are reproduced by the mathematical model we have developed to within 2% in "lightness" and about 8% in chromaticity. We are able to predict the colour of an analogue for a tooth, composed of bovine enamel and coloured paper, from the colour of an analogue for the dentine, the coloured paper alone, with good accuracy. This understanding provides insights into the role of dentine colour in determining tooth colour. Our work helps quantify the importance of dentine colour, compared to other, extrinsic causes of colour, such as staining, in determining the visible colour of teeth. Our predicted colours represent a baseline to which extrinsic sources will add. Copyright © 2015. Published by Elsevier Ltd.

Structural or pigmentary? Origin of the distinctive white stripe on the blue wing of a Morpho butterfly.

PubMed

Yoshioka, Shinya; Kinoshita, Shuichi

2006-01-22

A few species of Morpho butterflies have a distinctive white stripe pattern on their structurally coloured blue wings. Since the colour pattern of a butterfly wing is formed as a mosaic of differently coloured scales, several questions naturally arise: are the microstructures the same between the blue and white scales? How is the distinctive whiteness produced, structurally or by means of pigmentation? To answer these questions, we have performed structural and optical investigations of the stripe pattern of a butterfly, Morpho cypris. It is found that besides the dorsal and ventral scale layers, the wing substrate also has the corresponding stripe pattern. Quantitative optical measurements and analysis using a simple model for the wing structure reveal the origin of the higher reflectance which makes the white stripe brighter.

Colour influences perception of facial emotions but this effect is impaired in healthy ageing and schizophrenia.

PubMed

Silver, Henry; Bilker, Warren B

2015-01-01

Social cognition is commonly assessed by identification of emotions in facial expressions. Presence of colour, a salient feature of stimuli, might influence emotional face perception. We administered 2 tests of facial emotion recognition, the Emotion Recognition Test (ER40) using colour pictures and the Penn Emotional Acuity Test using monochromatic pictures, to 37 young healthy, 39 old healthy and 37 schizophrenic men. Among young healthy individuals recognition of emotions was more accurate and faster in colour than in monochromatic pictures. Compared to the younger group, older healthy individuals revealed impairment in identification of sad expressions in colour but not monochromatic pictures. Schizophrenia patients showed greater impairment in colour than monochromatic pictures of neutral and sad expressions and overall total score compared to both healthy groups. Patients showed significant correlations between cognitive impairment and perception of emotion in colour but not monochromatic pictures. Colour enhances perception of general emotional clues and this contextual effect is impaired in healthy ageing and schizophrenia. The effects of colour need to be considered in interpreting and comparing studies of emotion perception. Coloured face stimuli may be more sensitive to emotion processing impairments but less selective for emotion-specific information than monochromatic stimuli. This may impact on their utility in early detection of impairments and investigations of underlying mechanisms.

Wing scale ultrastructure underlying convergent and divergent iridescent colours in mimetic Heliconius butterflies.

PubMed

Parnell, Andrew J; Bradford, James E; Curran, Emma V; Washington, Adam L; Adams, Gracie; Brien, Melanie N; Burg, Stephanie L; Morochz, Carlos; Fairclough, J Patrick A; Vukusic, Pete; Martin, Simon J; Doak, Scott; Nadeau, Nicola J

2018-04-01

Iridescence is an optical phenomenon whereby colour changes with the illumination and viewing angle. It can be produced by thin film interference or diffraction. Iridescent optical structures are fairly common in nature, but relatively little is known about their production or evolution. Here we describe the structures responsible for producing blue-green iridescent colour in Heliconius butterflies. Overall the wing scale structures of iridescent and non-iridescent Heliconius species are very similar, both having longitudinal ridges joined by cross-ribs. However, iridescent scales have ridges composed of layered lamellae, which act as multilayer reflectors. Differences in brightness between species can be explained by the extent of overlap of the lamellae and their curvature as well as the density of ridges on the scale. Heliconius are well known for their Müllerian mimicry. We find that iridescent structural colour is not closely matched between co-mimetic species. Differences appear less pronounced in models of Heliconius vision than models of avian vision, suggesting that they are not driven by selection to avoid heterospecific courtship by co-mimics. Ridge profiles appear to evolve relatively slowly, being similar between closely related taxa, while ridge density evolves faster and is similar between distantly related co-mimics. © 2018 The Authors.

Wing scale ultrastructure underlying convergent and divergent iridescent colours in mimetic Heliconius butterflies

PubMed Central

Bradford, James E.; Curran, Emma V.; Washington, Adam L.; Adams, Gracie; Brien, Melanie N.; Burg, Stephanie L.; Morochz, Carlos; Fairclough, J. Patrick A.; Vukusic, Pete; Martin, Simon J.; Doak, Scott

2018-01-01

Iridescence is an optical phenomenon whereby colour changes with the illumination and viewing angle. It can be produced by thin film interference or diffraction. Iridescent optical structures are fairly common in nature, but relatively little is known about their production or evolution. Here we describe the structures responsible for producing blue-green iridescent colour in Heliconius butterflies. Overall the wing scale structures of iridescent and non-iridescent Heliconius species are very similar, both having longitudinal ridges joined by cross-ribs. However, iridescent scales have ridges composed of layered lamellae, which act as multilayer reflectors. Differences in brightness between species can be explained by the extent of overlap of the lamellae and their curvature as well as the density of ridges on the scale. Heliconius are well known for their Müllerian mimicry. We find that iridescent structural colour is not closely matched between co-mimetic species. Differences appear less pronounced in models of Heliconius vision than models of avian vision, suggesting that they are not driven by selection to avoid heterospecific courtship by co-mimics. Ridge profiles appear to evolve relatively slowly, being similar between closely related taxa, while ridge density evolves faster and is similar between distantly related co-mimics. PMID:29669892

Recent advances in the biomimicry of structural colours.

PubMed

Dumanli, Ahu Gümrah; Savin, Thierry

2016-12-21

Nature has mastered the construction of nanostructures with well-defined macroscopic effects and purposes. Structural colouration is a visible consequence of the particular patterning of a reflecting surface with regular structures at submicron length scales. Structural colours usually appear bright, shiny, iridescent or with a metallic look, as a result of physical processes such as diffraction, interference, or scattering with a typically small dissipative loss. These features have recently attracted much research effort in materials science, chemistry, engineering and physics, in order to understand and produce structural colours. In these early stages of photonics, researchers facing an infinite array of possible colour-producing structures are heavily inspired by the elaborate architectures they find in nature. We review here the recent technological strategies employed to artificially mimic the structural colours found in nature, as well as some of their current and potential applications.

Chromatic VEP in children with congenital colour vision deficiency.

PubMed

Tekavčič Pompe, Manca; Stirn Kranjc, Branka; Brecelj, Jelka

2010-09-01

Visual evoked potentials to chromatic stimulus (cVEP) are believed to selectively test the parvocellular visual pathway which is responsible for processing information about colour. The aim was to evaluate cVEP in children with red-green congenital colour vision deficiency. VEP responses of 15 colour deficient children were compared to 31 children with normal colour vision. An isoluminant red-green stimulus composed of horizontal gratings was presented in an onset-offset manner. The shape of the waveform was studied, as well as the latency and amplitude of positive (P) and negative (N) waves. cVEP response did not change much with increased age in colour deficient children, whereas normative data showed changes from a predominantly positive to a negative response with increased age. A P wave was present in 87% of colour deficient children (and in 100% of children with normal colour vision), whereas the N wave was absent in a great majority of colour deficient children and was present in 80% of children with normal colour vision. Therefore, the amplitude of the whole response (N-P) decreased linearly with age in colour deficient children, whereas in children with normal colour vision it increased linearly. P wave latency shortened with increased age in both groups. cVEP responses differ in children with congenital colour vision deficiency compared to children with normal colour vision. © 2010 The Authors, Ophthalmic and Physiological Optics © 2010 The College of Optometrists.

Up Scalable Full Colour Plasmonic Pixels with Controllable Hue, Brightness and Saturation.

PubMed

Mudachathi, Renilkumar; Tanaka, Takuo

2017-04-26

It has long been the interests of scientists to develop ink free colour printing technique using nano structured materials inspired by brilliant colours found in many creatures like butterflies and peacocks. Recently isolated metal nano structures exhibiting preferential light absorption and scattering have been explored as a promising candidate for this emerging field. Applying such structures in practical use, however, demands the production of individual colours with distinct reflective peaks, tunable across the visible wavelength region combined with controllable colour attributes and economically feasible fabrication. Herein, we present a simple yet efficient colour printing approach employing sub-micrometer scale plasmonic pixels of single constituent metal structure which supports near unity broadband light absorption at two distinct wavelengths, facilitating the creation of saturated colours. The dependence of these resonances on two different parameters of the same pixel enables controllable colour attributes such as hue, brightness and saturation across the visible spectrum. The linear dependence of colour attributes on the pixel parameters eases the automation; which combined with the use of inexpensive and stable aluminum as functional material will make this colour design strategy relevant for use in various commercial applications like printing micro images for security purposes, consumer product colouration and functionalized decoration to name a few.

Spectrophotometric Evaluation of Colour Stability of Nano Hybrid Composite Resin in Commonly Used Food Colourants in Asian Countries.

PubMed

Chittem, Jyothi; Sajjan, Girija S; Varma Kanumuri, Madhu

2017-01-01

There is growing interest in colour stability of aesthetic restorations. So far few studies have been reported. This study was designed to investigate the effects of different common food colourants i.e., Turmeric and Carmoisine (orange red dye) consumed by patients in Asian countries on a recent nano hybrid composite resin. A total of sixty disk shaped specimens measuring 10 mm in diameter and 2 mm in thickness were prepared. The samples were divided into two groups {Z 100 (Dental restorative composite) Filtek Z 250 XT (Nano hybrid universal restorative)}. Baseline colour measurement of all specimens were made using reflectance spectrophotometer with CIE L*a*b* system. Specimens were immersed in artificial saliva and different experimental solutions containing food colourants (carmoisine solution and turmeric solution) for three hours per day at 37°C. Colour measurements were made after 15 days. Colour difference (ΔE*) was calculated. Mean values were compared by one-way analysis of variance (ANOVA). Multiple range test by Tukey Post-hoc test procedure was employed to identify the significant groups at 5% level. Z 100 showed minimum staining capacity when compared to Z 250 XT in both the colourant solutions. The nanohybrid composite resin containing TEGDMA showed significant colour change when compared to that of microhybrid composite resin as a result of staining in turmeric and carmoisine solution.

Birds see the true colours of fruits to live off the fat of the land

PubMed Central

Schaefer, H. Martin; Valido, Alfredo; Jordano, Pedro

2014-01-01

Communication is a characteristic of life, but its reliability and basic definition are hotly debated. Theory predicts that trade among mutualists requires high reliability. Here, we show that moderate reliability already allows mutualists to optimize their rewards. The colours of Mediterranean fleshy-fruits indicate lipid rewards (but not other nutrients) to avian seed dispersers on regional and local scales. On the regional scale, fruits with high lipid content were significantly darker and less chromatic than congeners with lower lipid content. On the local scale, two warbler species (Sylvia atricapilla and Sylvia borin) selected fruit colours that were less chromatic, and thereby maximized their intake of lipids—a critical resource during migration and wintering. Crucially, birds were able to maximize lipid rewards with moderate reliability from visual fruit colours (r2 = 0.44–0.60). We suggest that mutualisms require only that any association between the quality and sensory aspects of signallers is learned through multiple, repeated interactions. Because these conditions are often fulfilled, also in social communication systems, we contend that selection on reliability is less intense than hitherto assumed. This may contribute to explaining the extraordinary diversity of signals, including that of plant reproductive displays. PMID:24403330

Characterisation of the n-colour printing process using the spot colour overprint model.

PubMed

Deshpande, Kiran; Green, Phil; Pointer, Michael R

2014-12-29

This paper is aimed at reproducing the solid spot colours using the n-colour separation. A simplified numerical method, called as the spot colour overprint (SCOP) model, was used for characterising the n-colour printing process. This model was originally developed for estimating the spot colour overprints. It was extended to be used as a generic forward characterisation model for the n-colour printing process. The inverse printer model based on the look-up table was implemented to obtain the colour separation for n-colour printing process. Finally the real-world spot colours were reproduced using 7-colour separation on lithographic offset printing process. The colours printed with 7 inks were compared against the original spot colours to evaluate the accuracy. The results show good accuracy with the mean CIEDE2000 value between the target colours and the printed colours of 2.06. The proposed method can be used successfully to reproduce the spot colours, which can potentially save significant time and cost in the printing and packaging industry.

The effect of colour congruency on shape discriminations of novel objects.

PubMed

Nicholson, Karen G; Humphrey, G Keith

2004-01-01

Although visual object recognition is primarily shape driven, colour assists the recognition of some objects. It is unclear, however, just how colour information is coded with respect to shape in long-term memory and how the availability of colour in the visual image facilitates object recognition. We examined the role of colour in the recognition of novel, 3-D objects by manipulating the congruency of object colour across the study and test phases, using an old/new shape-identification task. In experiment 1, we found that participants were faster at correctly identifying old objects on the basis of shape information when these objects were presented in their original colour, rather than in a different colour. In experiments 2 and 3, we found that participants were faster at correctly identifying old objects on the basis of shape information when these objects were presented with their original part-colour conjunctions, rather than in different or in reversed part-colour conjunctions. In experiment 4, we found that participants were quite poor at the verbal recall of part-colour conjunctions for correctly identified old objects, presented as grey-scale images at test. In experiment 5, we found that participants were significantly slower at correctly identifying old objects when object colour was incongruent across study and test, than when background colour was incongruent across study and test. The results of these experiments suggest that both shape and colour information are stored as part of the long-term representation of these novel objects. Results are discussed in terms of how colour might be coded with respect to shape in stored object representations.

Enamel color changes following orthodontic treatment.

PubMed

Pandian, Akshaya; Ranganathan, Sukanya; Padmanabhan, Sridevi

2017-01-01

To evaluate and compare the effect of various orthodontic bonding systems and clean up procedures on quantitative enamel colour change. A literature search was done to identify the studies that assessed the quantitative enamel colour change associated with the various bonding systems and cleanup procedures. Electronic database (Pub Med, Cochrane and Google Scholar) were searched. First stage screening was performed and the abstracts were selected according to the initial selection criteria. Full text articles were retrieved and analyzed during second stage screening. The bibliographies were reviewed to identify additional relevant studies. Sixteen full text articles were retrieved. Six were rejected because the methodology was different. There was significant enamel colour change following orthodontic bonding, debonding and clean up procedures. Self-etching primers produce less enamel colour change compared to conventional etching. Resin Modified GIC produces least colour change compared to other light cure and chemical cure systems. Polishing following the clean-up procedure reduces the colour change of the enamel.

Optimal colour quality of LED clusters based on memory colours.

PubMed

Smet, Kevin; Ryckaert, Wouter R; Pointer, Michael R; Deconinck, Geert; Hanselaer, Peter

2011-03-28

The spectral power distributions of tri- and tetrachromatic clusters of Light-Emitting-Diodes, composed of simulated and commercially available LEDs, were optimized with a genetic algorithm to maximize the luminous efficacy of radiation and the colour quality as assessed by the memory colour quality metric developed by the authors. The trade-off of the colour quality as assessed by the memory colour metric and the luminous efficacy of radiation was investigated by calculating the Pareto optimal front using the NSGA-II genetic algorithm. Optimal peak wavelengths and spectral widths of the LEDs were derived, and over half of them were found to be close to Thornton's prime colours. The Pareto optimal fronts of real LED clusters were always found to be smaller than those of the simulated clusters. The effect of binning on designing a real LED cluster was investigated and was found to be quite large. Finally, a real LED cluster of commercially available AlGaInP, InGaN and phosphor white LEDs was optimized to obtain a higher score on memory colour quality scale than its corresponding CIE reference illuminant.

Gene expression underlying adaptive variation in Heliconius wing patterns: non-modular regulation of overlapping cinnabar and vermilion prepatterns.

PubMed

Reed, Robert D; McMillan, W Owen; Nagy, Lisa M

2008-01-07

Geographical variation in the mimetic wing patterns of the butterfly Heliconius erato is a textbook example of adaptive polymorphism; however, little is known about how this variation is controlled developmentally. Using microarrays and qPCR, we identified and compared expression of candidate genes potentially involved with a red/yellow forewing band polymorphism in H. erato. We found that transcripts encoding the pigment synthesis enzymes cinnabar and vermilion showed pattern- and polymorphism-related expression patterns, respectively. cinnabar expression was associated with the forewing band regardless of pigment colour, providing the first gene expression pattern known to be correlated with a major Heliconius colour pattern. In contrast, vermilion expression changed spatially over time in red-banded butterflies, but was not expressed at detectable levels in yellow-banded butterflies, suggesting that regulation of this gene may be involved with the red/yellow polymorphism. Furthermore, we found that the yellow pigment, 3-hydroxykynurenine, is incorporated into wing scales from the haemolymph rather than being synthesized in situ. We propose that some aspects of Heliconius colour patterns are determined by spatio-temporal overlap of pigment gene transcription prepatterns and speculate that evolutionary changes in vermilion regulation may in part underlie an adaptive colour pattern polymorphism.

Effects of memory colour on colour constancy for unknown coloured objects

PubMed Central

Granzier, Jeroen J M; Gegenfurtner, Karl R

2012-01-01

The perception of an object's colour remains constant despite large variations in the chromaticity of the illumination—colour constancy. Hering suggested that memory colours, the typical colours of objects, could help in estimating the illuminant's colour and therefore be an important factor in establishing colour constancy. Here we test whether the presence of objects with diagnostical colours (fruits, vegetables, etc) within a scene influence colour constancy for unknown coloured objects in the scene. Subjects matched one of four Munsell papers placed in a scene illuminated under either a reddish or a greenish lamp with the Munsell book of colour illuminated by a neutral lamp. The Munsell papers were embedded in four different scenes—one scene containing diagnostically coloured objects, one scene containing incongruent coloured objects, a third scene with geometrical objects of the same colour as the diagnostically coloured objects, and one scene containing non-diagnostically coloured objects (eg, a yellow coffee mug). All objects were placed against a black background. Colour constancy was on average significantly higher for the scene containing the diagnostically coloured objects compared with the other scenes tested. We conclude that the colours of familiar objects help in obtaining colour constancy for unknown objects. PMID:23145282

Effects of memory colour on colour constancy for unknown coloured objects.

PubMed

Granzier, Jeroen J M; Gegenfurtner, Karl R

2012-01-01

The perception of an object's colour remains constant despite large variations in the chromaticity of the illumination-colour constancy. Hering suggested that memory colours, the typical colours of objects, could help in estimating the illuminant's colour and therefore be an important factor in establishing colour constancy. Here we test whether the presence of objects with diagnostical colours (fruits, vegetables, etc) within a scene influence colour constancy for unknown coloured objects in the scene. Subjects matched one of four Munsell papers placed in a scene illuminated under either a reddish or a greenish lamp with the Munsell book of colour illuminated by a neutral lamp. The Munsell papers were embedded in four different scenes-one scene containing diagnostically coloured objects, one scene containing incongruent coloured objects, a third scene with geometrical objects of the same colour as the diagnostically coloured objects, and one scene containing non-diagnostically coloured objects (eg, a yellow coffee mug). All objects were placed against a black background. Colour constancy was on average significantly higher for the scene containing the diagnostically coloured objects compared with the other scenes tested. We conclude that the colours of familiar objects help in obtaining colour constancy for unknown objects.

Liquid-induced colour change in a beetle: the concept of a photonic cell.

PubMed

Mouchet, Sébastien R; Van Hooijdonk, Eloise; Welch, Victoria L; Louette, Pierre; Colomer, Jean-François; Su, Bao-Lian; Deparis, Olivier

2016-01-13

The structural colour of male Hoplia coerulea beetles is notable for changing from blue to green upon contact with water. In fact, reversible changes in both colour and fluorescence are induced in this beetle by various liquids, although the mechanism has never been fully explained. Changes enacted by water are much faster than those by ethanol, in spite of ethanol's more rapid spread across the elytral surface. Moreover, the beetle's photonic structure is enclosed by a thin scale envelope preventing direct contact with the liquid. Here, we note the presence of sodium, potassium and calcium salts in the scale material that mediate the penetration of liquid through putative micropores. The result leads to the novel concept of a "photonic cell": namely, a biocompatible photonic structure that is encased by a permeable envelope which mediates liquid-induced colour changes in that photonic structure. Engineered photonic cells dispersed in culture media could revolutionize the monitoring of cell-metabolism.

Liquid-induced colour change in a beetle: the concept of a photonic cell

PubMed Central

Mouchet, Sébastien R.; Van Hooijdonk, Eloise; Welch, Victoria L.; Louette, Pierre; Colomer, Jean-François; Su, Bao-Lian; Deparis, Olivier

2016-01-01

The structural colour of male Hoplia coerulea beetles is notable for changing from blue to green upon contact with water. In fact, reversible changes in both colour and fluorescence are induced in this beetle by various liquids, although the mechanism has never been fully explained. Changes enacted by water are much faster than those by ethanol, in spite of ethanol’s more rapid spread across the elytral surface. Moreover, the beetle’s photonic structure is enclosed by a thin scale envelope preventing direct contact with the liquid. Here, we note the presence of sodium, potassium and calcium salts in the scale material that mediate the penetration of liquid through putative micropores. The result leads to the novel concept of a “photonic cell”: namely, a biocompatible photonic structure that is encased by a permeable envelope which mediates liquid-induced colour changes in that photonic structure. Engineered photonic cells dispersed in culture media could revolutionize the monitoring of cell-metabolism. PMID:26758681

Camouflage through colour change: mechanisms, adaptive value and ecological significance

PubMed Central

Flores, Augusto A. V.

2017-01-01

Animals from a wide range of taxonomic groups are capable of colour change, of which camouflage is one of the main functions. A considerable amount of past work on this subject has investigated species capable of extremely rapid colour change (in seconds). However, relatively slow colour change (over hours, days, weeks and months), as well as changes arising via developmental plasticity are probably more common than rapid changes, yet less studied. We discuss three key areas of colour change and camouflage. First, we review the mechanisms underpinning colour change and developmental plasticity for camouflage, including cellular processes, visual feedback, hormonal control and dietary factors. Second, we discuss the adaptive value of colour change for camouflage, including the use of different camouflage types. Third, we discuss the evolutionary–ecological implications of colour change for concealment, including what it can tell us about intraspecific colour diversity, morph-specific strategies, and matching to different environments and microhabitats. Throughout, we discuss key unresolved questions and present directions for future work, and highlight how colour change facilitates camouflage among habitats and arises when animals are faced with environmental changes occurring over a range of spatial and temporal scales. This article is part of the themed issue ‘Animal coloration: production, perception, function and application’. PMID:28533459

Camouflage through colour change: mechanisms, adaptive value and ecological significance.

PubMed

Duarte, Rafael C; Flores, Augusto A V; Stevens, Martin

2017-07-05

Animals from a wide range of taxonomic groups are capable of colour change, of which camouflage is one of the main functions. A considerable amount of past work on this subject has investigated species capable of extremely rapid colour change (in seconds). However, relatively slow colour change (over hours, days, weeks and months), as well as changes arising via developmental plasticity are probably more common than rapid changes, yet less studied. We discuss three key areas of colour change and camouflage. First, we review the mechanisms underpinning colour change and developmental plasticity for camouflage, including cellular processes, visual feedback, hormonal control and dietary factors. Second, we discuss the adaptive value of colour change for camouflage, including the use of different camouflage types. Third, we discuss the evolutionary-ecological implications of colour change for concealment, including what it can tell us about intraspecific colour diversity, morph-specific strategies, and matching to different environments and microhabitats. Throughout, we discuss key unresolved questions and present directions for future work, and highlight how colour change facilitates camouflage among habitats and arises when animals are faced with environmental changes occurring over a range of spatial and temporal scales.This article is part of the themed issue 'Animal coloration: production, perception, function and application'. © 2017 The Authors.

What colour does that feel? Tactile--visual mapping and the development of cross-modality.

PubMed

Ludwig, Vera U; Simner, Julia

2013-04-01

Humans share implicit preferences for cross-modal mappings (e.g., low pitch sounds are preferentially paired with darker colours). Individuals with synaesthesia experience cross-modal mappings to a conscious degree (e.g., they may see colours when they hear sounds). The neonatal synaesthesia hypothesis claims that all humans may be born with this explicit cross-modal perception, which dies out in most people through childhood, leaving only implicit associations in the average adult. Although there is evidence for decreasing cross-modality throughout early infancy, it is unclear whether this decline continues to take place throughout childhood and adolescence. This large-scale study had two goals. First, we aimed to establish whether human non-synaesthetes systematically map tactile and visual dimensions - a combination that has rarely been studied. Second, we asked whether tactile-visual associations may be more pronounced in younger compared to older participants. 210 participants between the ages of 5-74 years assigned colours to tactile stimuli. Smoothness, softness and roundness of stimuli positively correlated with luminance of the chosen colour; and smoothness and softness also positively correlated with chroma. Moreover, tactile sensations were associated with specific colours (e.g., softness with pink). There were no age differences for luminance effects. Chroma effects, however, were found exclusively in children and adolescents. Our findings are consistent with the neonatal synaesthesia hypothesis which suggests that all humans are born with strong cross-modal perception which is pruned away or inhibited throughout development. Moreover, the findings suggest that a decline of some forms of cross-modality may take place over a much longer time span than previously assumed. Copyright © 2012 Elsevier Ltd. All rights reserved.

A configural dominant account of contextual cueing: Configural cues are stronger than colour cues.

PubMed

Kunar, Melina A; John, Rebecca; Sweetman, Hollie

2014-01-01

Previous work has shown that reaction times to find a target in displays that have been repeated are faster than those for displays that have never been seen before. This learning effect, termed "contextual cueing" (CC), has been shown using contexts such as the configuration of the distractors in the display and the background colour. However, it is not clear how these two contexts interact to facilitate search. We investigated this here by comparing the strengths of these two cues when they appeared together. In Experiment 1, participants searched for a target that was cued by both colour and distractor configural cues, compared with when the target was only predicted by configural information. The results showed that the addition of a colour cue did not increase contextual cueing. In Experiment 2, participants searched for a target that was cued by both colour and distractor configuration compared with when the target was only cued by colour. The results showed that adding a predictive configural cue led to a stronger CC benefit. Experiments 3 and 4 tested the disruptive effects of removing either a learned colour cue or a learned configural cue and whether there was cue competition when colour and configural cues were presented together. Removing the configural cue was more disruptive to CC than removing colour, and configural learning was shown to overshadow the learning of colour cues. The data support a configural dominant account of CC, where configural cues act as the stronger cue in comparison to colour when they are presented together.

Visual and digital comparative tooth colour assessment methods and atomic force microscopy surface roughness.

PubMed

Grundlingh, A A; Grossman, E S; Shrivastava, S; Witcomb, M J

2013-10-01

This study compared digital and visual colour tooth colour assessment methods in a sample of 99 teeth consisting of incisors, canines and pre-molars. The teeth were equally divided between Control, Ozicure Oxygen Activator bleach and Opalescence Quick bleach and subjected to three treatments. Colour readings were recorded at nine intervals by two assessment methods, VITA Easyshade and VITAPAN 3D MASTER TOOTH GUIDE, giving a total of 1782 colour readings. Descriptive and statistical analysis was undertaken using a GLM test for Analysis of Variance for a Fractional Design set at a significance of P < 0.05. Atomic force micros copy was used to examine treated ename surfaces and establish surface roughness. Visual tooth colour assessment showed significance for the independent variables of treatment, number of treatments, tooth type and the combination tooth type and treatment. Digital colour assessment indicated treatment and tooth type to be of significance in tooth colour change. Poor agreement was found between visual and digital colour assessment methods for Control and Ozicure Oxygen Activator treatments. Surface roughness values increased two-fold for Opalescence Quick specimens over the two other treatments, implying that increased light scattering improved digital colour reading. Both digital and visual colour matching methods should be used in tooth bleaching studies to complement each other and to compensate for deficiencies.

Impact of colour blindness on recognition of haematuria in bladder cancer patients.

PubMed

Katmawi-Sabbagh, Samer; Haq, Ahsanul; Jain, Sunila; Subhas, Gokul; Turnham, Helen

2009-01-01

Colour blindness might lead to failure in recognizing frank haematuria. Our aim is to investigate as to whether colour-blind males who develop bladder cancer present later with less favourable histology. Two hundred male patients with bladder cancer were assessed using Ishihara plate test for colour deficiency. Degree of haematuria, method of presentation and initial histologic findings were also determined. Colour-blind patients who develop bladder cancer present with less favourable histology compared with non-colour-blind (p = 0.01). Colour blindness was associated with presentation with more advanced bladder tumours.

The description of physical signs of illness in photographs by physicians with abnormal colour vision.

PubMed

Campbell, John L; Spalding, J Anthony B; Mir, Fraz A

2004-07-01

Physicians with congenital colour vision deficiency (CCVD) have reported difficulties recognising certain physical signs of illness, for example, jaundice, red rashes and pallor, and interpreting coloured charts, diagrams and slide projections. However, there has been little study of the effects of CCVD on the performance of medical practitioners. The aim of this study was to look for evidence of the effect of CCVD on the ability of physicians to recognise and describe physical signs of illness that have colour as either the main or an important feature. Twenty-three general practitioners with CCVD were shown 11 colour photographs depicting colour signs of illness and were asked to describe the signs they saw and rate their confidence in making their descriptions. Their responses were compared to those of 23 age-matched general practitioners with normal colour vision. General practitioners with CCVD compared to those with normal colour vision had less ability and confidence in detecting physical signs in the photographs and naming the colours. The results of this study support other evidence that physicians with CCVD have difficulties detecting some colour signs of illness and naming the colours. Because of the use of photographs the extent of the problem in clinical practice is unknown but medical practitioners with CCVD should be aware of the possibility of failing to detect or correctly assess physical signs that are characterised by colour.

A comparative analysis of colour preferences in temperate and tropical social bees.

PubMed

Balamurali, G S; Nicholls, Elizabeth; Somanathan, Hema; Hempel de Ibarra, Natalie

2018-01-02

The spontaneous occurrence of colour preferences without learning has been demonstrated in several insect species; however, the underlying mechanisms are still not understood. Here, we use a comparative approach to investigate spontaneous and learned colour preferences in foraging bees of two tropical and one temperate species. We hypothesised that tropical bees utilise different sets of plants and therefore might differ in their spontaneous colour preferences. We tested colour-naive bees and foragers from colonies that had been enclosed in large flight cages for a long time. Bees were shortly trained with triplets of neutral, UV-grey stimuli placed randomly at eight locations on a black training disk to induce foraging motivation. During unrewarded tests, the bees' responses to eight colours were video-recorded. Bees explored all colours and displayed an overall preference for colours dominated by long or short wavelengths, rather than a single colour stimulus. Naive Apis cerana and Bombus terrestris showed similar choices. Both inspected long-wavelength stimuli more than short-wavelength stimuli, whilst responses of the tropical stingless bee Tetragonula iridipennis differed, suggesting that resource partitioning could be a determinant of spontaneous colour preferences. Reward on an unsaturated yellow colour shifted the bees' preference curves as predicted, which is in line with previous findings that brief colour experience overrides the expression of spontaneous preferences. We conclude that rather than determining foraging behaviour in inflexible ways, spontaneous colour preferences vary depending on experimental settings and reflect potential biases in mechanisms of learning and decision-making in pollinating insects.

A comparative analysis of colour preferences in temperate and tropical social bees

NASA Astrophysics Data System (ADS)

Balamurali, G. S.; Nicholls, Elizabeth; Somanathan, Hema; Hempel de Ibarra, Natalie

2018-02-01

The spontaneous occurrence of colour preferences without learning has been demonstrated in several insect species; however, the underlying mechanisms are still not understood. Here, we use a comparative approach to investigate spontaneous and learned colour preferences in foraging bees of two tropical and one temperate species. We hypothesised that tropical bees utilise different sets of plants and therefore might differ in their spontaneous colour preferences. We tested colour-naive bees and foragers from colonies that had been enclosed in large flight cages for a long time. Bees were shortly trained with triplets of neutral, UV-grey stimuli placed randomly at eight locations on a black training disk to induce foraging motivation. During unrewarded tests, the bees' responses to eight colours were video-recorded. Bees explored all colours and displayed an overall preference for colours dominated by long or short wavelengths, rather than a single colour stimulus. Naive Apis cerana and Bombus terrestris showed similar choices. Both inspected long-wavelength stimuli more than short-wavelength stimuli, whilst responses of the tropical stingless bee Tetragonula iridipennis differed, suggesting that resource partitioning could be a determinant of spontaneous colour preferences. Reward on an unsaturated yellow colour shifted the bees' preference curves as predicted, which is in line with previous findings that brief colour experience overrides the expression of spontaneous preferences. We conclude that rather than determining foraging behaviour in inflexible ways, spontaneous colour preferences vary depending on experimental settings and reflect potential biases in mechanisms of learning and decision-making in pollinating insects.

Tests of commercial colour CMOS cameras for astronomical applications

NASA Astrophysics Data System (ADS)

Pokhvala, S. M.; Reshetnyk, V. M.; Zhilyaev, B. E.

2013-12-01

We present some results of testing commercial colour CMOS cameras for astronomical applications. Colour CMOS sensors allow to perform photometry in three filters simultaneously that gives a great advantage compared with monochrome CCD detectors. The Bayer BGR colour system realized in colour CMOS sensors is close to the astronomical Johnson BVR system. The basic camera characteristics: read noise (e^{-}/pix), thermal noise (e^{-}/pix/sec) and electronic gain (e^{-}/ADU) for the commercial digital camera Canon 5D MarkIII are presented. We give the same characteristics for the scientific high performance cooled CCD camera system ALTA E47. Comparing results for tests of Canon 5D MarkIII and CCD ALTA E47 show that present-day commercial colour CMOS cameras can seriously compete with the scientific CCD cameras in deep astronomical imaging.

Interactions between colour and synaesthetic colour: an effect of simultaneous colour contrast on synaesthetic colours.

PubMed

Nijboer, Tanja C W; Gebuis, Titia; te Pas, Susan F; van der Smagt, Maarten J

2011-01-01

We investigated whether simultaneous colour contrast affects the synaesthetic colour experience and normal colour percept in a similar manner. We simultaneously presented a target stimulus (i.e. grapheme) and a reference stimulus (i.e. hash). Either the grapheme or the hash was presented on a saturated background of the same or opposite colour category as the synaesthetic colour and the other stimulus on a grey background. In both conditions, grapheme-colour synaesthetes were asked to colour the hash in a colour similar to the synaesthetic colour of the grapheme. Controls that were pair-matched to the synaesthetes performed the same experiment, but for them, the grapheme was presented in the colour induced by the grapheme in synaesthetes. When graphemes were presented on a grey and the hash on a coloured background, a traditional simultaneous colour-contrast effect was found for controls as well as synaesthetes. When graphemes were presented on colour and the hash on grey, the controls again showed a traditional simultaneous colour-contrast effect, whereas the synaesthetes showed the opposite effect. Our results show that synaesthetic colour experiences differ from normal colour perception; both are susceptible to different surrounding colours, but not in a comparable manner. Copyright © 2010 Elsevier Ltd. All rights reserved.

Colour application on mammography image segmentation

NASA Astrophysics Data System (ADS)

Embong, R.; Aziz, N. M. Nik Ab.; Karim, A. H. Abd; Ibrahim, M. R.

2017-09-01

The segmentation process is one of the most important steps in image processing and computer vision since it is vital in the initial stage of image analysis. Segmentation of medical images involves complex structures and it requires precise segmentation result which is necessary for clinical diagnosis such as the detection of tumour, oedema, and necrotic tissues. Since mammography images are grayscale, researchers are looking at the effect of colour in the segmentation process of medical images. Colour is known to play a significant role in the perception of object boundaries in non-medical colour images. Processing colour images require handling more data, hence providing a richer description of objects in the scene. Colour images contain ten percent (10%) additional edge information as compared to their grayscale counterparts. Nevertheless, edge detection in colour image is more challenging than grayscale image as colour space is considered as a vector space. In this study, we implemented red, green, yellow, and blue colour maps to grayscale mammography images with the purpose of testing the effect of colours on the segmentation of abnormality regions in the mammography images. We applied the segmentation process using the Fuzzy C-means algorithm and evaluated the percentage of average relative error of area for each colour type. The results showed that all segmentation with the colour map can be done successfully even for blurred and noisy images. Also the size of the area of the abnormality region is reduced when compare to the segmentation area without the colour map. The green colour map segmentation produced the smallest percentage of average relative error (10.009%) while yellow colour map segmentation gave the largest percentage of relative error (11.367%).

Independent effects of colour on object identification and memory.

PubMed

Lloyd-Jones, Toby J; Nakabayashi, Kazuyo

2009-02-01

We examined the effects of colour on object identification and memory using a study-test priming procedure with a coloured-object decision task at test (i.e., deciding whether an object is correctly coloured). Objects were selected to have a single associated colour and were either correctly or incorrectly coloured. In addition, object shape and colour were either spatially integrated (i.e., colour fell on the object surface) or spatially separated (i.e., colour formed the background to the object). Transforming the colour of an object from study to test (e.g., from a yellow banana to a purple banana) reduced priming of response times, as compared to when the object was untransformed. This utilization of colour information in object memory was not contingent upon colour falling on the object surface or whether the resulting configuration was of a correctly or incorrectly coloured object. In addition, we observed independent effects of colour on response times, whereby coloured-object decisions were more efficient for correctly than for incorrectly coloured objects but only when colour fell on the object surface. These findings provide evidence for two distinct mechanisms of shape-colour binding in object processing.

Changeable camouflage: how well can flounder resemble the colour and spatial scale of substrates in their natural habitats?

PubMed Central

Akkaynak, Derya; Siemann, Liese A.; Barbosa, Alexandra

2017-01-01

Flounder change colour and pattern for camouflage. We used a spectrometer to measure reflectance spectra and a digital camera to capture body patterns of two flounder species camouflaged on four natural backgrounds of different spatial scale (sand, small gravel, large gravel and rocks). We quantified the degree of spectral match between flounder and background relative to the situation of perfect camouflage in which flounder and background were assumed to have identical spectral distribution. Computations were carried out for three biologically relevant observers: monochromatic squid, dichromatic crab and trichromatic guitarfish. Our computations present a new approach to analysing datasets with multiple spectra that have large variance. Furthermore, to investigate the spatial match between flounder and background, images of flounder patterns were analysed using a custom program originally developed to study cuttlefish camouflage. Our results show that all flounder and background spectra fall within the same colour gamut and that, in terms of different observer visual systems, flounder matched most substrates in luminance and colour contrast. Flounder matched the spatial scales of all substrates except for rocks. We discuss findings in terms of flounder biology; furthermore, we discuss our methodology in light of hyperspectral technologies that combine high-resolution spectral and spatial imaging. PMID:28405370

Changeable camouflage: how well can flounder resemble the colour and spatial scale of substrates in their natural habitats?

PubMed

Akkaynak, Derya; Siemann, Liese A; Barbosa, Alexandra; Mäthger, Lydia M

2017-03-01

Flounder change colour and pattern for camouflage. We used a spectrometer to measure reflectance spectra and a digital camera to capture body patterns of two flounder species camouflaged on four natural backgrounds of different spatial scale (sand, small gravel, large gravel and rocks). We quantified the degree of spectral match between flounder and background relative to the situation of perfect camouflage in which flounder and background were assumed to have identical spectral distribution. Computations were carried out for three biologically relevant observers: monochromatic squid, dichromatic crab and trichromatic guitarfish. Our computations present a new approach to analysing datasets with multiple spectra that have large variance. Furthermore, to investigate the spatial match between flounder and background, images of flounder patterns were analysed using a custom program originally developed to study cuttlefish camouflage. Our results show that all flounder and background spectra fall within the same colour gamut and that, in terms of different observer visual systems, flounder matched most substrates in luminance and colour contrast. Flounder matched the spatial scales of all substrates except for rocks. We discuss findings in terms of flounder biology; furthermore, we discuss our methodology in light of hyperspectral technologies that combine high-resolution spectral and spatial imaging.

The colour of an avifauna: A quantitative analysis of the colour of Australian birds

PubMed Central

Delhey, Kaspar

2015-01-01

Animal coloration is a poorly-understood aspect of phenotypic variability. Here I expand initial studies of the colour gamut of birds by providing the first quantitative description of the colour variation of an entire avifauna: Australian landbirds (555 species). The colour of Australian birds occupies a small fraction (19%) of the entire possible colour space and colour variation is extremely uneven. Most colours are unsaturated, concentrated in the centre of colour space and based on the deposition of melanins. Other mechanisms of colour production are less common but account for larger portions of colour space and for most saturated colours. Male colours occupy 45–25% more colour space than female colours, indicating that sexual dichromatism translates into a broader range of male colours. Male-exclusive colours are often saturated, at the edge of chromatic space, and have most likely evolved for signalling. While most clades of birds occupy expected or lower-than-expected colour volumes, parrots and cockatoos (Order Psittaciformes) occupy a much larger volume than expected. This uneven distribution of colour variation across mechanisms of colour production, sexes and clades is probably shared by avifaunas in other parts of the world, but this remains to be tested with comparable data. PMID:26679370

The prevalence of tooth discolouration and the self-satisfaction with tooth colour in a Chinese urban population.

PubMed

Xiao, J; Zhou, X D; Zhu, W C; Zhang, B; Li, J Y; Xu, X

2007-05-01

To determine the prevalence of tooth discolouration, self-satisfaction with tooth colour, and correlation with socio-demographic-behavioural factors in adults and teenagers in Chengdu, China. A cross-sectional survey. 405 Chinese urban adults and teenagers from a multistage random probability sample. Tooth colour was measured on the maxillary central incisors using a colorimeter. Tooth discolouration was determined according to the discolouration level figure and evaluation criteria. Self-satisfaction with tooth colour was assessed on a five-point qualitative scale. Data were coded and analyzed using SPSS software. The mean values for L*, a* and b* were 70.67 (s.d. 1.91), 4.29 (s.d. 2.05) and 17.51 (s.d. 4.13), respectively. Age and sex were the most important factors associated with tooth colour (P < 0.05). About half of the study population (48.9%) suffered from some tooth discolouration, and 52.6% were dissatisfied with their tooth colour. Education and smoking were significant factors affecting self-satisfaction with tooth colour (P < 0.05). Tooth discolouration is common among the Chinese, and many Chinese are dissatisfied with their tooth colour. Self-satisfaction with tooth colour decreased with increasing severity of discolouration. Further research is needed to determine types of tooth discolouration among broader regions in China.

A major gene controls mimicry and crypsis in butterflies and moths

PubMed Central

Nadeau, Nicola J.; Pardo-Diaz, Carolina; Whibley, Annabel; Supple, Megan; Saenko, Suzanne V.; Wallbank, Richard W. R.; Wu, Grace C.; Maroja, Luana; Ferguson, Laura; Hanly, Joseph J.; Hines, Heather; Salazar, Camilo; Merrill, Richard; Dowling, Andrea; ffrench-Constant, Richard; Llaurens, Violaine; Joron, Mathieu; McMillan, W. Owen; Jiggins, Chris D.

2016-01-01

The wing patterns of butterflies and moths (Lepidoptera) are diverse and striking examples of evolutionary diversification by natural selection1,2. Lepidopteran wing colour patterns are a key innovation, consisting of arrays of coloured scales. We still lack a general understanding of how these patterns are controlled and if there is any commonality across the 160,000 moth and 17,000 butterfly species. Here, we identify a gene, cortex, through fine-scale mapping using population genomics and gene expression analyses, which regulates pattern switches in multiple species across the mimetic radiation in Heliconius butterflies. cortex belongs to a fast evolving subfamily of the otherwise highly conserved fizzy family of cell cycle regulators3, suggesting that it most likely regulates pigmentation patterning through regulation of scale cell development. In parallel with findings in the peppered moth (Biston betularia)4, our results suggest that this mechanism is common within Lepidoptera and that cortex has become a major target for natural selection acting on colour and pattern variation in this group of insects. PMID:27251285

Influence of colour on acquisition and generalisation of graphic symbols.

PubMed

Hetzroni, O E; Ne'eman, A

2013-07-01

Children with autism may benefit from using graphic symbols for their communication, language and literacy development. The purpose of this study was to investigate the influence of colour versus grey-scale displays on the identification of graphic symbols using a computer-based intervention. An alternating treatment design was employed to examine the learning and generalisation of 58 colour and grey-scale symbols by four preschool children with autism. The graphic symbols were taught via a meaning-based intervention using stories and educational games. Results demonstrate that all of the children were able to learn and maintain symbol identification over time for both symbol displays with no apparent differences. Differences were apparent for two of the children who exhibited better generalisation when learning grey-scale symbols first. The other two showed no noticeable difference, between displays when generalising from one display to the other. Implications and further research are discussed. © 2012 The Authors. Journal of Intellectual Disability Research © 2012 John Wiley & Sons Ltd, MENCAP & IASSID.

The gene cortex controls mimicry and crypsis in butterflies and moths.

PubMed

Nadeau, Nicola J; Pardo-Diaz, Carolina; Whibley, Annabel; Supple, Megan A; Saenko, Suzanne V; Wallbank, Richard W R; Wu, Grace C; Maroja, Luana; Ferguson, Laura; Hanly, Joseph J; Hines, Heather; Salazar, Camilo; Merrill, Richard M; Dowling, Andrea J; ffrench-Constant, Richard H; Llaurens, Violaine; Joron, Mathieu; McMillan, W Owen; Jiggins, Chris D

2016-06-02

The wing patterns of butterflies and moths (Lepidoptera) are diverse and striking examples of evolutionary diversification by natural selection. Lepidopteran wing colour patterns are a key innovation, consisting of arrays of coloured scales. We still lack a general understanding of how these patterns are controlled and whether this control shows any commonality across the 160,000 moth and 17,000 butterfly species. Here, we use fine-scale mapping with population genomics and gene expression analyses to identify a gene, cortex, that regulates pattern switches in multiple species across the mimetic radiation in Heliconius butterflies. cortex belongs to a fast-evolving subfamily of the otherwise highly conserved fizzy family of cell-cycle regulators, suggesting that it probably regulates pigmentation patterning by regulating scale cell development. In parallel with findings in the peppered moth (Biston betularia), our results suggest that this mechanism is common within Lepidoptera and that cortex has become a major target for natural selection acting on colour and pattern variation in this group of insects.

Tooth colour change with Ozicure Oxygen Activator: a comparative in vitro tooth bleaching study.

PubMed

Grundlingh, A A; Grossman, E S; Witcomb, M J

2012-08-01

This in vitro study compared a new tooth bleaching product, Ozicure Oxygen Activator (O3, RSA) with Opalescence Quick (Ultradent, USA) using a randomised block design to assess tooth colour change. Colour change, stability and relapse in canine, incisor and premolar teeth was assessed following three bleach treatments and subsequent tooth colour assessment. Ninety nine teeth (canines, incisors and premolars), which were caries free, had no surface defects and were within the colour range 1M2 and 5M3 were selected. Teeth were randomly divided into the three experimental groups: Opalescence Quick, Ozicure Oxygen Activator and control. The three experimental groups received three treatments of one hour each over three consecutive days. Tooth colour was assessed using the Vitapan 3D Master Tooth Guide (VITA, Germany). A General Linear Models test for analysis of variance for a fractional design with significance set at P < 0.05 was used to test for significance. Both bleaching methods significantly lightened the teeth (P < 0.0001). Tooth colour change was mainly after the first hour of tooth bleaching. The tooth type was significant in tooth colour change (P = 0.0416). Tooth colour relapse and resistance to colour change were observed. Ozicure Oxygen Activator bleached teeth in a manner and to an extent similar to Opalescence Quick.

Increased conspicuousness can explain the match between visual sensitivities and blue plumage colours in fairy-wrens.

PubMed

Delhey, Kaspar; Hall, Michelle; Kingma, Sjouke A; Peters, Anne

2013-01-07

Colour signals are expected to match visual sensitivities of intended receivers. In birds, evolutionary shifts from violet-sensitive (V-type) to ultraviolet-sensitive (U-type) vision have been linked to increased prevalence of colours rich in shortwave reflectance (ultraviolet/blue), presumably due to better perception of such colours by U-type vision. Here we provide the first test of this widespread idea using fairy-wrens and allies (Family Maluridae) as a model, a family where shifts in visual sensitivities from V- to U-type eyes are associated with male nuptial plumage rich in ultraviolet/blue colours. Using psychophysical visual models, we compared the performance of both types of visual systems at two tasks: (i) detecting contrast between male plumage colours and natural backgrounds, and (ii) perceiving intraspecific chromatic variation in male plumage. While U-type outperforms V-type vision at both tasks, the crucial test here is whether U-type vision performs better at detecting and discriminating ultraviolet/blue colours when compared with other colours. This was true for detecting contrast between plumage colours and natural backgrounds (i), but not for discriminating intraspecific variability (ii). Our data indicate that selection to maximize conspicuousness to conspecifics may have led to the correlation between ultraviolet/blue colours and U-type vision in this clade of birds.

Colour Terms Affect Detection of Colour and Colour-Associated Objects Suppressed from Visual Awareness

PubMed Central

Forder, Lewis; Taylor, Olivia; Mankin, Helen; Scott, Ryan B.; Franklin, Anna

2016-01-01

The idea that language can affect how we see the world continues to create controversy. A potentially important study in this field has shown that when an object is suppressed from visual awareness using continuous flash suppression (a form of binocular rivalry), detection of the object is differently affected by a preceding word prime depending on whether the prime matches or does not match the object. This may suggest that language can affect early stages of vision. We replicated this paradigm and further investigated whether colour terms likewise influence the detection of colours or colour-associated object images suppressed from visual awareness by continuous flash suppression. This method presents rapidly changing visual noise to one eye while the target stimulus is presented to the other. It has been shown to delay conscious perception of a target for up to several minutes. In Experiment 1 we presented greyscale photos of objects. They were either preceded by a congruent object label, an incongruent label, or white noise. Detection sensitivity (d’) and hit rates were significantly poorer for suppressed objects preceded by an incongruent label compared to a congruent label or noise. In Experiment 2, targets were coloured discs preceded by a colour term. Detection sensitivity was significantly worse for suppressed colour patches preceded by an incongruent colour term as compared to a congruent term or white noise. In Experiment 3 targets were suppressed greyscale object images preceded by an auditory presentation of a colour term. On congruent trials the colour term matched the object’s stereotypical colour and on incongruent trials the colour term mismatched. Detection sensitivity was significantly poorer on incongruent trials than congruent trials. Overall, these findings suggest that colour terms affect awareness of coloured stimuli and colour- associated objects, and provide new evidence for language-perception interaction in the brain. PMID:27023274

Colour Terms Affect Detection of Colour and Colour-Associated Objects Suppressed from Visual Awareness.

PubMed

Forder, Lewis; Taylor, Olivia; Mankin, Helen; Scott, Ryan B; Franklin, Anna

2016-01-01

The idea that language can affect how we see the world continues to create controversy. A potentially important study in this field has shown that when an object is suppressed from visual awareness using continuous flash suppression (a form of binocular rivalry), detection of the object is differently affected by a preceding word prime depending on whether the prime matches or does not match the object. This may suggest that language can affect early stages of vision. We replicated this paradigm and further investigated whether colour terms likewise influence the detection of colours or colour-associated object images suppressed from visual awareness by continuous flash suppression. This method presents rapidly changing visual noise to one eye while the target stimulus is presented to the other. It has been shown to delay conscious perception of a target for up to several minutes. In Experiment 1 we presented greyscale photos of objects. They were either preceded by a congruent object label, an incongruent label, or white noise. Detection sensitivity (d') and hit rates were significantly poorer for suppressed objects preceded by an incongruent label compared to a congruent label or noise. In Experiment 2, targets were coloured discs preceded by a colour term. Detection sensitivity was significantly worse for suppressed colour patches preceded by an incongruent colour term as compared to a congruent term or white noise. In Experiment 3 targets were suppressed greyscale object images preceded by an auditory presentation of a colour term. On congruent trials the colour term matched the object's stereotypical colour and on incongruent trials the colour term mismatched. Detection sensitivity was significantly poorer on incongruent trials than congruent trials. Overall, these findings suggest that colour terms affect awareness of coloured stimuli and colour- associated objects, and provide new evidence for language-perception interaction in the brain.

Behavioural evidence of colour vision in free flying stingless bees.

PubMed

Spaethe, J; Streinzer, M; Eckert, J; May, S; Dyer, A G

2014-06-01

Colour vision was first demonstrated with behavioural experiments in honeybees 100 years ago. Since that time a wealth of quality physiological data has shown a highly conserved set of trichromatic colour receptors in most bee species. Despite the subsequent wealth of behavioural research on honeybees and bumblebees, there currently is a relative dearth of data on stingless bees, which are the largest tribe of the eusocial bees comprising of more than 600 species. In our first experiment we tested Trigona cf. fuscipennis, a stingless bee species from Costa Rica in a field setting using the von Frisch method and show functional colour vision. In a second experiment with these bees, we use a simultaneous colour discrimination test designed for honeybees to enable a comparative analysis of relative colour discrimination. In a third experiment, we test in laboratory conditions Tetragonula carbonaria, an Australian stingless bee species using a similar simultaneous colour discrimination test. Both stingless bee species show relatively poorer colour discrimination compared to honeybees and bumblebees; and we discuss the value of being able to use these behavioural methods to efficiently extend our current knowledge of colour vision and discrimination in different bee species.

Colour-causing defects and their related optoelectronic transitions in single crystal CVD diamond.

PubMed

Khan, R U A; Cann, B L; Martineau, P M; Samartseva, J; Freeth, J J P; Sibley, S J; Hartland, C B; Newton, M E; Dhillon, H K; Twitchen, D J

2013-07-10

Defects causing colour in nitrogen-doped chemical vapour-deposited (CVD) diamond can adversely affect the exceptional optical, electronic and spintronic properties of the material. Several techniques were used to study these defects, namely optical absorption spectroscopy, thermoluminescence (TL) and electron paramagnetic resonance (EPR). From our studies, the defects causing colour in nitrogen-doped CVD diamond are clearly not the same as those causing similar colour in natural diamonds. The brown colour arises due to a featureless absorption profile that decreases in intensity with increasing wavelength, and a broad feature at 360 nm (3.49 eV) that scales in intensity with it. Another prominent absorption band, centred at 520 nm (2.39 eV), is ascribed to the neutral nitrogen-vacancy-hydrogen defect. The defects responsible for the brown colour possess acceptor states that are 1.5 eV from the valence band (VB) edge. The brown colour is removed by heat treatment at 1600 ° C, whereupon new defects possessing shallow (<1 eV) trap states are generated.

Analytical halo model of galactic conformity

NASA Astrophysics Data System (ADS)

Pahwa, Isha; Paranjape, Aseem

2017-09-01

We present a fully analytical halo model of colour-dependent clustering that incorporates the effects of galactic conformity in a halo occupation distribution framework. The model, based on our previous numerical work, describes conformity through a correlation between the colour of a galaxy and the concentration of its parent halo, leading to a correlation between central and satellite galaxy colours at fixed halo mass. The strength of the correlation is set by a tunable 'group quenching efficiency', and the model can separately describe group-level correlations between galaxy colour (1-halo conformity) and large-scale correlations induced by assembly bias (2-halo conformity). We validate our analytical results using clustering measurements in mock galaxy catalogues, finding that the model is accurate at the 10-20 per cent level for a wide range of luminosities and length-scales. We apply the formalism to interpret the colour-dependent clustering of galaxies in the Sloan Digital Sky Survey (SDSS). We find good overall agreement between the data and a model that has 1-halo conformity at a level consistent with previous results based on an SDSS group catalogue, although the clustering data require satellites to be redder than suggested by the group catalogue. Within our modelling uncertainties, however, we do not find strong evidence of 2-halo conformity driven by assembly bias in SDSS clustering.

Teaching the Absorption of Light Colours Using an Artificial Rainbow

ERIC Educational Resources Information Center

Yurumezoglu, Kemal; Isik, Hakan; Arikan, Gizem; Kabay, Gozde

2015-01-01

This paper presents an experimental activity based on the absorption of light colours by pigments. The activity is constructed using a stepwise design and offers an opportunity for students and teachers to compare and generalize the interactions between light and pigment colours. The light colours composing an artificial rainbow produced in the…

In multiple situational light settings, visual observation for skin colour assessment is comparable with colorimeter measurement.

PubMed

Wright, C Y; Wilkes, M; du Plessis, J L; Reeder, A I; Albers, P N

2016-08-01

Finding inexpensive and reliable techniques for assessing skin colour is important, given that it is related to several adverse human health outcomes. Visual observation is considered a subjective approach assessment and, even when made by trained assessor, concern has been raised about the need for controlled lighting in the study venue. The aim of this study is to determine whether visual skin colour assessments correlate with objective skin colour measurements in study venues with different lighting types and configurations. Two trained investigators, with confirmed visual acuity, visually classified the inner, upper arm skin colour of 556 adults using Munsell(®) colour classifications converted to Individual Typology Angle (°ITA) values based on published data. Skin colour at the same anatomic site was also measured using a colorimeter. Each participant was assessed in one of 10 different buildings, each with a different study day. Munsell(®) -derived °ITA values were compared to colorimeter °ITA values for the full sample and by building/day. We found a strong positive, monotonic correlation between Munsell(®) derived °ITA values and colorimeter °ITA values for all participants (Spearman ρ = 0.8585, P < 0.001). Similar relationships were found when Munsell(®) and colorimeter °ITA values were compared for participants assessed in the same building for all 10 buildings (Spearman ρ values ranged from 0.797 to 0.934, all correlations were statistically significant at P < 0.001). It is possible to visually assess individual skin colour in multiple situational lighting settings and retrieve results that are comparable with objective measurements of skin colour. This was true for individuals of varying population groups and skin pigmentation. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Limits of colour vision in dim light.

PubMed

Kelber, Almut; Lind, Olle

2010-09-01

Humans and most vertebrates have duplex retinae with multiple cone types for colour vision in bright light, and one single rod type for achromatic vision in dim light. Instead of comparing signals from multiple spectral types of photoreceptors, such species use one highly sensitive receptor type thus improving the signal-to-noise ratio at night. However, the nocturnal hawkmoth Deilephila elpenor, the nocturnal bee Xylocopa tranquebarica and the nocturnal gecko Tarentola chazaliae can discriminate colours at extremely dim light intensities. To be able to do so, they sacrifice spatial and temporal resolution in favour of colour vision. We review what is known about colour vision in dim light, and compare colour vision thresholds with the optical sensitivity of the photoreceptors in selected animal species with lens and compound eyes. © 2010 The Authors, Ophthalmic and Physiological Optics © 2010 The College of Optometrists.

Comparative treatment of dye-rich wastewater in engineered wetland systems (EWSs) vegetated with different plants.

PubMed

Mbuligwe, Stephen E

2005-01-01

In Dar es Salaam City there are more than a thousand tie-and-dye (TAD) small-scale industries (SSIs) that discharge dye-rich wastewater indiscriminately with resultant water pollution. Due to the decentralised nature of the TAD SSIs, coupled with financial constraints facing their operators, control of their pollution needs a simple cost-effective waste treatment technology. Engineered wetland systems (EWSs) constitute such a technology. A pilot scale EWS was evaluated with respect to its effectiveness in treating dye-rich wastewater. The role of wetland plants was assessed through comparing treatment performance efficiencies between an unplanted and vegetated EWS beds. On the whole, it has been demonstrated that the EWS has the potential to effectively treat dye-rich wastewater. Colour, which is the most apparent problem issue with textile wastewater, was reduced by 72-77%. COD was reduced by 68-73%, while sulphate was reduced by 53-59%. The proportionately high COD removal suggests the reduction in colour was accompanied by almost complete degradation of dyes and daughter products. The overall treatment efficiency of the vegetated units was more than twice as high as that of the unplanted bed. On average, the bed vegetated with coco yam plants performed better (7.6%) than the one planted with cattail plants.

Image Simulation and Assessment of the Colour and Spatial Capabilities of the Colour and Stereo Surface Imaging System (CaSSIS) on the ExoMars Trace Gas Orbiter

NASA Astrophysics Data System (ADS)

Tornabene, Livio L.; Seelos, Frank P.; Pommerol, Antoine; Thomas, Nicholas; Caudill, C. M.; Becerra, Patricio; Bridges, John C.; Byrne, Shane; Cardinale, Marco; Chojnacki, Matthew; Conway, Susan J.; Cremonese, Gabriele; Dundas, Colin M.; El-Maarry, M. R.; Fernando, Jennifer; Hansen, Candice J.; Hansen, Kayle; Harrison, Tanya N.; Henson, Rachel; Marinangeli, Lucia; McEwen, Alfred S.; Pajola, Maurizio; Sutton, Sarah S.; Wray, James J.

2018-02-01

This study aims to assess the spatial and visible/near-infrared (VNIR) colour/spectral capabilities of the 4-band Colour and Stereo Surface Imaging System (CaSSIS) aboard the ExoMars 2016 Trace Grace Orbiter (TGO). The instrument response functions for the CaSSIS imager was used to resample spectral libraries, modelled spectra and to construct spectrally ( i.e., in I/F space) and spatially consistent simulated CaSSIS image cubes of various key sites of interest and for ongoing scientific investigations on Mars. Coordinated datasets from Mars Reconnaissance Orbiter (MRO) are ideal, and specifically used for simulating CaSSIS. The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) provides colour information, while the Context Imager (CTX), and in a few cases the High-Resolution Imaging Science Experiment (HiRISE), provides the complementary spatial information at the resampled CaSSIS unbinned/unsummed pixel resolution (4.6 m/pixel from a 400-km altitude). The methodology used herein employs a Gram-Schmidt spectral sharpening algorithm to combine the ˜18-36 m/pixel CRISM-derived CaSSIS colours with I/F images primarily derived from oversampled CTX images. One hundred and eighty-one simulated CaSSIS 4-colour image cubes (at 18-36 m/pixel) were generated (including one of Phobos) based on CRISM data. From these, thirty-three "fully"-simulated image cubes of thirty unique locations on Mars ( i.e., with 4 colour bands at 4.6 m/pixel) were made. All simulated image cubes were used to test both the colour capabilities of CaSSIS by producing standard colour RGB images, colour band ratio composites (CBRCs) and spectral parameters. Simulated CaSSIS CBRCs demonstrated that CaSSIS will be able to readily isolate signatures related to ferrous (Fe2+) iron- and ferric (Fe3+) iron-bearing deposits on the surface of Mars, ices and atmospheric phenomena. Despite the lower spatial resolution of CaSSIS when compared to HiRISE, the results of this work demonstrate that CaSSIS will not only compliment HiRISE-scale studies of various geological and seasonal phenomena, it will also enhance them by providing additional colour and geologic context through its wider and longer full-colour coverage (˜9.4 × 50 km), and its increased sensitivity to iron-bearing materials from its two IR bands (RED and NIR). In a few examples, subtle surface changes that were not easily detected by HiRISE were identified in the simulated CaSSIS images. This study also demonstrates the utility of the Gram-Schmidt spectral pan-sharpening technique to extend VNIR colour/spectral capabilities from a lower spatial resolution colour/spectral dataset to a single-band or panchromatic image greyscale image with higher resolution. These higher resolution colour products (simulated CaSSIS or otherwise) are useful as means to extend both geologic context and mapping of datasets with coarser spatial resolutions. The results of this study indicate that the TGO mission objectives, as well as the instrument-specific mission objectives, will be achievable with CaSSIS.

Validity and reliability of haemoglobin colour scale and its comparison with clinical signs in diagnosing anaemia in pregnancy in Ahmedabad, India.

PubMed

Bala, D V; Vyas, S; Shukla, A; Tiwari, H; Bhatt, G; Gupta, K

2012-07-01

This study compared the validity of the haemoglobin colour scale (HCS) and clinical signs in diagnosing anaemia against Sahli's haemoglobinometer method as the gold standard, and assessed the reliability of HCS. The sample comprised 129 pregnant women recruited from 6 urban health centres in Ahmedabad. The prevalence of anaemia was 69.8% by Sahli's method, 78.3% by HCS and 89.9% by clinical signs; there was no statistically significant difference between Sahli's method and HCS whereas there was between Sahlis method and clinical signs. The mean haemoglobin level by Sahli's method and HCS differed significantly. The sensitivity, specificity, positive predictive value and negative predictive value of HCS was 83.3%, 33.3%, 74.3% and 46.4% respectively and that of clinical signs was 91.1%, 12.8%, 70.7% and 38.5% respectively. Interobserver agreement for HCS was moderate (K = 0.43). Clinical signs are better than HCS for diagnosing anaemia. HCS can be used in the field provided assessors are adequately trained.

Impregnation with antimicrobials has an impact on degree of conversion and colour stability of acrylic liner.

PubMed

Salim, Nesreen; Satterthwaite, Julian; Rautemaa, Riina; Silikas, Nick

2012-01-01

This study investigated the impact of impregnation of a poly(ethyl methacrylate) /tetrahydrofurfuryl methacrylate (PEM/THFM) polymer with chlorhexidine or fluconazole on the degree of conversion (DC) and colour stability (ΔE). The DC of uncured (0 h) and cured (24 h) samples was analysed by Fourier transform infrared spectroscopy (FTIR) and colour stability was analysed colorimetrically. The DC percentage of the control samples was significantly greater than those containing chlorhexidine and fluconazole (p≤0.05). The control discs exhibited only slight colour change compared to the impregnated discs which showed marked colour change (p≤0.05). A strong negative correlation between the extent of colour change and the degree of conversion was detected (r=0.97). The DC and colour stability were influenced by the addition of chlorhexidine or fluconazole. However, the final values were comparable to other commonly used acrylic liners and within acceptable ranges. PEM/THFM can be considered as a biocompatible drug delivery system.

Influence of Colour on Acquisition and Generalisation of Graphic Symbols

ERIC Educational Resources Information Center

Hetzroni, O. E.; Ne'eman, A.

2013-01-01

Background: Children with autism may benefit from using graphic symbols for their communication, language and literacy development. The purpose of this study was to investigate the influence of colour versus grey-scale displays on the identification of graphic symbols using a computer-based intervention. Method: An alternating treatment design was…

Image quality characteristics of a novel colour scanning digital ophthalmoscope (SDO) compared with fundus photography.

PubMed

Strauss, Rupert W; Krieglstein, Tina R; Priglinger, Siegfried G; Reis, Werner; Ulbig, Michael W; Kampik, Anselm; Neubauer, Aljoscha S

2007-11-01

To establish a set of quality parameters for grading image quality and apply those to evaluate the fundus image quality obtained by a new scanning digital ophthalmoscope (SDO) compared with standard slide photography. On visual analogue scales a total of eight image characteristics were defined: overall quality, contrast, colour brilliance, focus (sharpness), resolution and details, noise, artefacts and validity of clinical assessment. Grading was repeated after 4 months to assess repeatability. Fundus images of 23 patients imaged digitally by SDO and by Zeiss 450FF fundus camera using Kodak film were graded side-by-side by three graders. Lens opacity was quantified with the Interzeag Lens Opacity Meter 701. For all of the eight scales of image quality, good repeatability within the graders (mean Kendall's W 0.69) was obtained after 4 months. Inter-grader agreement ranged between 0.31 and 0.66. Despite the SDO's limited nominal image resolution of 720 x 576 pixels, the Zeiss FF 450 camera performed better in only two of the subscales - noise (p = 0.001) and artefacts (p = 0.01). Lens opacities significantly influenced only the two subscales 'resolution' and 'details', which deteriorated with increasing media opacities for both imaging systems. Distinct scales to grade image characteristics of different origin were developed and validated. Overall SDO digital imaging was found to provide fundus pictures of a similarly high level of quality as expert photography on slides.

Galaxy cluster luminosities and colours, and their dependence on cluster mass and merger state

NASA Astrophysics Data System (ADS)

Mulroy, Sarah L.; McGee, Sean L.; Gillman, Steven; Smith, Graham P.; Haines, Chris P.; Démoclès, Jessica; Okabe, Nobuhiro; Egami, Eiichi

2017-12-01

We study a sample of 19 galaxy clusters in the redshift range 0.15 < z < 0.30 with highly complete spectroscopic membership catalogues (to K < K*(z) + 1.5) from the Arizona Cluster Redshift Survey, individual weak-lensing masses and near-infrared data from the Local Cluster Substructure Survey, and optical photometry from the Sloan Digital Sky Survey. We fit the scaling relations between total cluster luminosity in each of six bandpasses (grizJK) and cluster mass, finding cluster luminosity to be a promising mass proxy with low intrinsic scatter σln L|M of only ∼10-20 per cent for all relations. At fixed overdensity radius, the intercept increases with wavelength, consistent with an old stellar population. The scatter and slope are consistent across all wavelengths, suggesting that cluster colour is not a function of mass. Comparing colour with indicators of the level of disturbance in the cluster, we find a narrower variety in the cluster colours of 'disturbed' clusters than of 'undisturbed' clusters. This trend is more pronounced with indicators sensitive to the initial stages of a cluster merger, e.g. the Dressler Schectman statistic. We interpret this as possible evidence that the total cluster star formation rate is 'standardized' in mergers, perhaps through a process such as a system-wide shock in the intracluster medium.

Calibration/validation of Landsat-Derived Ocean Colour Products in Boston Harbour

NASA Astrophysics Data System (ADS)

Pahlevan, Nima; Sheldon, Patrick; Peri, Francesco; Wei, Jianwei; Shang, Zhehai; Sun, Qingsong; Chen, Robert F.; Lee, Zhongping; Schaaf, Crystal B.; Schott, John R.; Loveland, Thomas

2016-06-01

The Landsat data archive provides a unique opportunity to investigate the long-term evolution of coastal ecosystems at fine spatial scales that cannot be resolved by ocean colour (OC) satellite sensors. Recognizing Landsat's limitations in applications over coastal waters, we have launched a series of field campaigns in Boston Harbor and Massachusetts Bay (MA, USA) to validate OC products derived from Landsat-8. We will provide a preliminary demonstration on the calibration/validation of the existing OC algorithms (atmospheric correction and in-water optical properties) to enhance monitoring efforts in Boston Harbor. To do so, Landsat optical images were first compared against ocean colour products over high-latitude regions. The in situ cruise data, including optical data (remote sensing reflectance) and water samples were analyzed to obtain insights into the optical and biogeochemical properties of near-surface waters. Along with the cruise data, three buoys were deployed in three locations across the Harbor to complement our database of concentrations of chlorophyll a, total suspended solids (TSS), and absorption of colour dissolved organic matter (CDOM). The data collected during the first year of the project are used to develop and/or tune OC algorithms. The data will be combined with historic field data to map in-water constituents back to the early 1990's. This paper presents preliminary analysis of some of the data collected under Landsat-8 overpasses.

Determination of HER2 amplification in primary breast cancer using dual-colour chromogenic in situ hybridization is comparable to fluorescence in situ hybridization: a European multicentre study involving 168 specimens.

PubMed

García-Caballero, Tomás; Grabau, Dorthe; Green, Andrew R; Gregory, John; Schad, Arno; Kohlwes, Elke; Ellis, Ian O; Watts, Sarah; Mollerup, Jens

2010-03-01

Fluorescence in situ hybridization (FISH) can be used to reveal several genomic imbalances relevant to proper cancer diagnosis and to the correct treatment regime. However, FISH requires expensive and advanced fluorescence microscopes in addition to expertise in fluorescence microscopy. To determine whether a newly developed dual-colour chromogenic in situ hybridization (CISH) method is a suitable alternative to FISH, we analysed the human epidermal growth factor receptor 2 gene (HER2) amplification level of 168 breast cancer specimens using dual-colour CISH and FISH and compared the results. We found 100% agreement between HER2 status determined by FISH and dual-colour CISH. Furthermore, we observed that the time used to score slides was significantly reduced by 28% in dual-colour CISH compared with the FISH protocol. Concordance between HER2 protein status and dual-colour CISH or FISH was equally good with an overall agreement of 96.8%. Correlation between the HER2/centromere 17 gene ratios obtained with dual-colour CISH and FISH was highly significant with an overall correlation coefficient (rho) of 0.96. We conclude that dual-colour CISH and bright field microscopy are excellent alternatives to FISH when analysing the HER2 status of primary breast cancer.

New Brown Dwarf Discs in Upper Scorpius Observed with WISE

NASA Technical Reports Server (NTRS)

Dawson, P.; Scholz, A.; Ray, T. P.; Natta, A.; Marsh, K. A.; Padgett, D.; Ressler, M. E.

2013-01-01

We present a census of the disc population for UKIDSS selected brown dwarfs in the 5-10 Myr old Upper Scorpius OB association. For 116 objects originally identified in UKIDSS, the majority of them not studied in previous publications, we obtain photometry from the Wide-Field Infrared Survey Explorer data base. The resulting colour magnitude and colour colour plots clearly show two separate populations of objects, interpreted as brown dwarfs with discs (class II) and without discs (class III). We identify 27 class II brown dwarfs, 14 of them not previously known. This disc fraction (27 out of 116, or 23%) among brown dwarfs was found to be similar to results for K/M stars in Upper Scorpius, suggesting that the lifetimes of discs are independent of the mass of the central object for low-mass stars and brown dwarfs. 5 out of 27 discs (19 per cent) lack excess at 3.4 and 4.6 microns and are potential transition discs (i.e. are in transition from class II to class III). The transition disc fraction is comparable to low-mass stars.We estimate that the time-scale for a typical transition from class II to class III is less than 0.4 Myr for brown dwarfs. These results suggest that the evolution of brown dwarf discs mirrors the behaviour of discs around low-mass stars, with disc lifetimes of the order of 5 10 Myr and a disc clearing time-scale significantly shorter than 1 Myr.

The Potential Impact of Directionality, Colour Perceptions and Cultural Associations on Disaster Messages During Heatwaves in the UK

PubMed Central

Tang, Chris; Rundblad, Gabriella

2015-01-01

The health risks posed by heatwaves have been well documented. In the UK, before and during a heatwave, alerts are issued to the general public based on a tiered warning system integrating the use of colour and number sequences. There has of yet been no formal assessment of the public response to these messages. Cultural and language barriers make some members of ethnic minority communities particularly hard to reach. These may be less challenging amongst younger community members, who may be well placed to instigate the circulation of warning information to those less able or willing to use conventional channels. This qualitative study assesses the role of age and ethnic and cultural background in the conceptualisation of the number and colour systems used as part of the Heat-Health Watch System (HHWS) and the National Severe Weather Warning Service (NSWWS). Young and older participants were recruited from the Bangladeshi and white British populations of Tower Hamlets. All participants were given a cognitive task that required them to identify and draw associations between 12 cards depicting the four colours and numbers used in the warning system and four pictures providing contextualisation in terms of heatwave risk. A qualitative analysis of the heuristics used in the group discussions provided insights into the conceptualisations basic to interpreting colour and number sequences as representations of risk graduations, and how interpretation might be influenced by age and ethnic and cultural background. There were considerable differences in the interpretation of young Bangladeshi and older white British participants, on the one hand, and older Bangladeshi participants, on the other. Young Bangladeshis and older white British participants conceptualised the colours and numbers as a vertical scale, with the numbers/colours at “the top” corresponding to representations of higher temperature. This conceptualisation was mainly based on strong associations between colour and temperature, with risk only associated with the upper limit of the scale. Older Bangladeshi participants, on the other hand, conceptualised the numbers and pictures as a narrative sequence and disassociated the colours from the other cards. The differences between groups suggest potential cultural barriers to the “intended” interpretation of the colour and number sequences for older Bangladeshis but not for young Bangladeshis. The fact that the predominant association for the colour sequence for both young Bangladeshis and older white British participants was with graduations of temperature rather than risk raises questions about the applicability of using colours in a tiered warning system. PMID:25932346

Plasmonic colour generation

NASA Astrophysics Data System (ADS)

Kristensen, Anders; Yang, Joel K. W.; Bozhevolnyi, Sergey I.; Link, Stephan; Nordlander, Peter; Halas, Naomi J.; Mortensen, N. Asger

2017-01-01

Plasmonic colours are structural colours that emerge from resonant interactions between light and metallic nanostructures. The engineering of plasmonic colours is a promising, rapidly emerging research field that could have a large technological impact. We highlight basic properties of plasmonic colours and recent nanofabrication developments, comparing technology-performance indicators for traditional and nanophotonic colour technologies. The structures of interest include diffraction gratings, nanoaperture arrays, thin films, and multilayers and structures that support Mie resonances and whispering-gallery modes. We discuss plasmonic colour nanotechnology based on localized surface plasmon resonances, such as gap plasmons and hybridized disk-hole plasmons, which allow for colour printing with sub-diffraction resolution. We also address a range of fabrication approaches that enable large-area printing and nanoscale lithography compatible with complementary metal-oxide semiconductor technologies, including nanoimprint lithography and self-assembly. Finally, we review recent developments in dynamically reconfigurable plasmonic colours and in the laser-induced post-processing of plasmonic colour surfaces.

The effect of colour on children's cognitive performance.

PubMed

Brooker, Alice; Franklin, Anna

2016-06-01

The presence of red appears to hamper adults' cognitive performance relative to other colours (see Elliot & Maier, 2014, Ann. Rev. Psychol. 65, 95). Here, we investigate whether colour affects cognitive performance in 8- and 9-year-olds. Children completed a battery of tasks once in the presence of a coloured screen that was one of eight colours and once in the presence of a grey screen. Performance was assessed for each colour relative to the grey baseline, and differences across colours were compared. We find a significant difference in performance across colours, with significantly worse performance in the presence of red than grey. The effect of colour did not significantly interact with task. The findings suggest that colour can affect children's cognitive performance and that there is a detrimental effect of red. Findings are related to the adult literature and implications for educational contexts are discussed. © 2015 The British Psychological Society.

Statistical colour models: an automated digital image analysis method for quantification of histological biomarkers.

PubMed

Shu, Jie; Dolman, G E; Duan, Jiang; Qiu, Guoping; Ilyas, Mohammad

2016-04-27

Colour is the most important feature used in quantitative immunohistochemistry (IHC) image analysis; IHC is used to provide information relating to aetiology and to confirm malignancy. Statistical modelling is a technique widely used for colour detection in computer vision. We have developed a statistical model of colour detection applicable to detection of stain colour in digital IHC images. Model was first trained by massive colour pixels collected semi-automatically. To speed up the training and detection processes, we removed luminance channel, Y channel of YCbCr colour space and chose 128 histogram bins which is the optimal number. A maximum likelihood classifier is used to classify pixels in digital slides into positively or negatively stained pixels automatically. The model-based tool was developed within ImageJ to quantify targets identified using IHC and histochemistry. The purpose of evaluation was to compare the computer model with human evaluation. Several large datasets were prepared and obtained from human oesophageal cancer, colon cancer and liver cirrhosis with different colour stains. Experimental results have demonstrated the model-based tool achieves more accurate results than colour deconvolution and CMYK model in the detection of brown colour, and is comparable to colour deconvolution in the detection of pink colour. We have also demostrated the proposed model has little inter-dataset variations. A robust and effective statistical model is introduced in this paper. The model-based interactive tool in ImageJ, which can create a visual representation of the statistical model and detect a specified colour automatically, is easy to use and available freely at http://rsb.info.nih.gov/ij/plugins/ihc-toolbox/index.html . Testing to the tool by different users showed only minor inter-observer variations in results.

Increased conspicuousness can explain the match between visual sensitivities and blue plumage colours in fairy-wrens

PubMed Central

Delhey, Kaspar; Hall, Michelle; Kingma, Sjouke A.; Peters, Anne

2013-01-01

Colour signals are expected to match visual sensitivities of intended receivers. In birds, evolutionary shifts from violet-sensitive (V-type) to ultraviolet-sensitive (U-type) vision have been linked to increased prevalence of colours rich in shortwave reflectance (ultraviolet/blue), presumably due to better perception of such colours by U-type vision. Here we provide the first test of this widespread idea using fairy-wrens and allies (Family Maluridae) as a model, a family where shifts in visual sensitivities from V- to U-type eyes are associated with male nuptial plumage rich in ultraviolet/blue colours. Using psychophysical visual models, we compared the performance of both types of visual systems at two tasks: (i) detecting contrast between male plumage colours and natural backgrounds, and (ii) perceiving intraspecific chromatic variation in male plumage. While U-type outperforms V-type vision at both tasks, the crucial test here is whether U-type vision performs better at detecting and discriminating ultraviolet/blue colours when compared with other colours. This was true for detecting contrast between plumage colours and natural backgrounds (i), but not for discriminating intraspecific variability (ii). Our data indicate that selection to maximize conspicuousness to conspecifics may have led to the correlation between ultraviolet/blue colours and U-type vision in this clade of birds. PMID:23118438

Poor environmental tracking can make extinction risk insensitive to the colour of environmental noise

PubMed Central

van de Pol, Martijn; Vindenes, Yngvild; Sæther, Bernt-Erik; Engen, Steinar; Ens, Bruno J.; Oosterbeek, Kees; Tinbergen, Joost M.

2011-01-01

The relative importance of environmental colour for extinction risk compared with other aspects of environmental noise (mean and interannual variability) is poorly understood. Such knowledge is currently relevant, as climate change can cause the mean, variability and temporal autocorrelation of environmental variables to change. Here, we predict that the extinction risk of a shorebird population increases with the colour of a key environmental variable: winter temperature. However, the effect is weak compared with the impact of changes in the mean and interannual variability of temperature. Extinction risk was largely insensitive to noise colour, because demographic rates are poor in tracking the colour of the environment. We show that three mechanisms—which probably act in many species—can cause poor environmental tracking: (i) demographic rates that depend nonlinearly on environmental variables filter the noise colour, (ii) demographic rates typically depend on several environmental signals that do not change colour synchronously, and (iii) demographic stochasticity whitens the colour of demographic rates at low population size. We argue that the common practice of assuming perfect environmental tracking may result in overemphasizing the importance of noise colour for extinction risk. Consequently, ignoring environmental autocorrelation in population viability analysis could be less problematic than generally thought. PMID:21561978

Directional Limits on Motion Transparency Assessed Through Colour-Motion Binding.

PubMed

Maloney, Ryan T; Clifford, Colin W G; Mareschal, Isabelle

2018-03-01

Motion-defined transparency is the perception of two or more distinct moving surfaces at the same retinal location. We explored the limits of motion transparency using superimposed surfaces of randomly positioned dots defined by differences in motion direction and colour. In one experiment, dots were red or green and we varied the proportion of dots of a single colour that moved in a single direction ('colour-motion coherence') and measured the threshold direction difference for discriminating between two directions. When colour-motion coherences were high (e.g., 90% of red dots moving in one direction), a smaller direction difference was required to correctly bind colour with direction than at low coherences. In another experiment, we varied the direction difference between the surfaces and measured the threshold colour-motion coherence required to discriminate between them. Generally, colour-motion coherence thresholds decreased with increasing direction differences, stabilising at direction differences around 45°. Different stimulus durations were compared, and thresholds were higher at the shortest (150 ms) compared with the longest (1,000 ms) duration. These results highlight different yet interrelated aspects of the task and the fundamental limits of the mechanisms involved: the resolution of narrowly separated directions in motion processing and the local sampling of dot colours from each surface.

The colour of blood in skin: a comparison of Allen's test and photonics simulations.

PubMed

Välisuo, Petri; Kaartinen, Ilkka; Kuokkanen, Hannu; Alander, Jarmo

2010-11-01

The colour of the skin reflects many physiological and pathological states of an individual. Usually, the skin colour is examined by the bare eye alone. Several scaling systems have been developed to quantify the sensory evaluation of skin colour. In this work, the reflectance of the skin is measured directly using an objective instrument. Haemoglobin inside the dermal circulation is one of the key factors of skin colour and it also has a major role in the appearance of many skin lesions and scars. To quantitatively measure and analyse such conditions, the relation between the skin colour and the haemoglobin concentration in the skin needs to be resolved. To examine the effect of blood concentration on the skin colour, five Allen's tests were performed on 20 persons. The skin colour change was measured using a spectrophotometer by changing the blood concentration by the Allen's test. Light interaction with the skin was simulated with a Monte Carlo model, tuning the blood concentration parameter until the simulated and the measured spectra matched, yielding the relationship between the skin colour and the blood concentration. The simulation produced spectra similar to those measured. The change in the blood concentration in the simulation model and in the skin produced changes similar to the spectra. The reflectance of the skin was found to be a nonlinear function of the blood concentration. The relationship found between skin colour and blood concentration makes it possible to quantify those skin conditions expressed by blood volume better than plain colour. © 2010 John Wiley & Sons A/S.

Geographic divergence and colour change in response to visual backgrounds and illumination intensity in bearded dragons.

PubMed

Cadena, Viviana; Smith, Kathleen R; Endler, John A; Stuart-Fox, Devi

2017-03-15

Animals may improve camouflage by both dynamic colour change and local evolutionary adaptation of colour but we have little understanding of their relative importance in colour-changing species. We tested for differences in colour change in response to background colour and light intensity in two populations of central bearded dragon lizards ( Pogona vitticeps ) representing the extremes in body coloration and geographical range. We found that bearded dragons change colour in response to various backgrounds and that colour change is affected by illumination intensity. Within-individual colour change was similar in magnitude in the two populations but varied between backgrounds. However, at the endpoints of colour change, each population showed greater similarity to backgrounds that were representative of the local habitat compared with the other population, indicating local adaptation to visual backgrounds. Our results suggest that even in species that change colour, both phenotypic plasticity and geographic divergence of coloration may contribute to improved camouflage. © 2017. Published by The Company of Biologists Ltd.

Automated colour identification in melanocytic lesions.

PubMed

Sabbaghi, S; Aldeen, M; Garnavi, R; Varigos, G; Doliantis, C; Nicolopoulos, J

2015-08-01

Colour information plays an important role in classifying skin lesion. However, colour identification by dermatologists can be very subjective, leading to cases of misdiagnosis. Therefore, a computer-assisted system for quantitative colour identification is highly desirable for dermatologists to use. Although numerous colour detection systems have been developed, few studies have focused on imitating the human visual perception of colours in melanoma application. In this paper we propose a new methodology based on QuadTree decomposition technique for automatic colour identification in dermoscopy images. Our approach mimics the human perception of lesion colours. The proposed method is trained on a set of 47 images from NIH dataset and applied to a test set of 190 skin lesions obtained from PH2 dataset. The results of our proposed method are compared with a recently reported colour identification method using the same dataset. The effectiveness of our method in detecting colours in dermoscopy images is vindicated by obtaining approximately 93% accuracy when the CIELab1 colour space is used.

Fecundity selection on ornamental plumage colour differs between ages and sexes and varies over small spatial scales.

PubMed

Parker, T H; Wilkin, T A; Barr, I R; Sheldon, B C; Rowe, L; Griffith, S C

2011-07-01

Avian plumage colours are some of the most conspicuous sexual ornaments, and yet standardized selection gradients for plumage colour have rarely been quantified. We examined patterns of fecundity selection on plumage colour in blue tits (Cyanistes caeruleus L.). When not accounting for environmental heterogeneity, we detected relatively few cases of selection. We found significant disruptive selection on adult male crown colour and yearling female chest colour and marginally nonsignificant positive linear selection on adult female crown colour. We discovered no new significant selection gradients with canonical rotation of the matrix of nonlinear selection. Next, using a long-term data set, we identified territory-level environmental variables that predicted fecundity to determine whether these variables influenced patterns of plumage selection. The first of these variables, the density of oaks within 50 m of the nest, influenced selection gradients only for yearling males. The second variable, an inverse function of nesting density, interacted with a subset of plumage selection gradients for yearling males and adult females, although the strength and direction of selection did not vary predictably with population density across these analyses. Overall, fecundity selection on plumage colour in blue tits appeared rare and inconsistent among sexes and age classes. © 2011 The Authors. Journal of Evolutionary Biology © 2011 European Society For Evolutionary Biology.

Spatial reflection patterns of iridescent wings of male pierid butterflies: curved scales reflect at a wider angle than flat scales.

PubMed

Pirih, Primož; Wilts, Bodo D; Stavenga, Doekele G

2011-10-01

The males of many pierid butterflies have iridescent wings, which presumably function in intraspecific communication. The iridescence is due to nanostructured ridges of the cover scales. We have studied the iridescence in the males of a few members of Coliadinae, Gonepteryx aspasia, G. cleopatra, G. rhamni, and Colias croceus, and in two members of the Colotis group, Hebomoia glaucippe and Colotis regina. Imaging scatterometry demonstrated that the pigmentary colouration is diffuse whereas the structural colouration creates a directional, line-shaped far-field radiation pattern. Angle-dependent reflectance measurements demonstrated that the directional iridescence distinctly varies among closely related species. The species-dependent scale curvature determines the spatial properties of the wing iridescence. Narrow beam illumination of flat scales results in a narrow far-field iridescence pattern, but curved scales produce broadened patterns. The restricted spatial visibility of iridescence presumably plays a role in intraspecific signalling.

Sputum colour and bacteria in chronic bronchitis exacerbations: a pooled analysis.

PubMed

Miravitlles, Marc; Kruesmann, Frank; Haverstock, Daniel; Perroncel, Renee; Choudhri, Shurjeel H; Arvis, Pierre

2012-06-01

We examined the correlation between sputum colour and the presence of potentially pathogenic bacteria in acute exacerbations of chronic bronchitis (AECBs). Data were pooled from six multicentre studies comparing moxifloxacin with other antimicrobials in patients with an AECB. Sputum was collected before antimicrobial therapy, and bacteria were identified by culture and Gram staining. Association between sputum colour and bacteria was determined using logistic regression. Of 4,089 sputum samples, a colour was reported in 4,003; 1,898 (46.4%) were culture-positive. Green or yellow sputum samples were most likely to yield bacteria (58.9% and 45.5% of samples, respectively), compared with 18% of clear and 39% of rust-coloured samples positive for potentially pathogenic microorganisms. Factors predicting a positive culture were sputum colour (the strongest predictor), sputum purulence, increased dyspnoea, male sex and absence of fever. Green or yellow versus white sputum colour was associated with a sensitivity of 94.7% and a specificity of 15% for the presence of bacteria. Sputum colour, particularly green and yellow, was a stronger predictor of potentially pathogenic bacteria than sputum purulence and increased dyspnoea in AECB patients. However, it does not necessarily predict the need for antibiotic treatment in all patients with AECB.

Universal scaling of strange particle pT spectra in pp collisions

NASA Astrophysics Data System (ADS)

Yang, Liwen; Wang, Yanyun; Hao, Wenhui; Liu, Na; Du, Xiaoling; Zhang, Wenchao

2018-04-01

As a complementary study to that performed on the transverse momentum (pT) spectra of charged pions, kaons and protons in proton-proton (pp) collisions at LHC energies 0.9, 2.76 and 7TeV, we present a scaling behaviour in the pT spectra of strange particles (KS0, Λ, Ξ and φ) at these three energies. This scaling behaviour is exhibited when the spectra are expressed in a suitable scaling variable z=pT/K, where the scaling parameter K is determined by the quality factor method and increases with the center of mass energy (√{s}). The rates at which K increases with ln √{s} for these strange particles are found to be identical within errors. In the framework of the colour string percolation model, we argue that these strange particles are produced through the decay of clusters that are formed by the colour strings overlapping. We observe that the strange mesons and baryons are produced from clusters with different size distributions, while the strange mesons (baryons) KS0 and φ ( Λ and Ξ) originate from clusters with the same size distributions. The cluster's size distributions for strange mesons are more dispersed than those for strange baryons. The scaling behaviour of the pT spectra for these strange particles can be explained by the colour string percolation model in a quantitative way.

Effect of illumination on colour vision testing with Farnsworth-Munsell 100 hue test: customized colour vision booth versus room illumination.

PubMed

Zahiruddin, Kowser; Banu, Shaj; Dharmarajan, Ramya; Kulothungan, Vaitheeswaran; Vijayan, Deepa; Raman, Rajiv; Sharma, Tarun

2010-06-01

To evaluate a customized, portable Farnsworth-Munsell 100 (FM 100) hue viewing booth for compliance with colour vision testing standards and to compare it with room illumination in subjects with normal colour vision (trichromats), subjects with acquired colour vision defects (secondary to diabetes mellitus), and subjects with congenital colour vision defects (dichromats). Discrete wavelengths of the tube in the customized booth were measured using a spectrometer using the normal incident method and were compared with the spectral distribution of sunlight. Forty-eight subjects were recruited for the study and were divided into 3 groups: Group 1, Normal Trichromats (30 eyes); Group 2, Congenital Colour Vision Defects (16 eyes); and Group 3, Diabetes Mellitus (20 eyes). The FM 100 hue test performance was compared using two illumination conditions, booth illumination and room illumination. Total error scores of the classical method in Group 2 as mean+/-SD for room and booth illumination was 243.05+/-85.96 and 149.85+/-54.50 respectively (p=0.0001). Group 2 demonstrated lesser correlation (r=0.50, 0.55), lesser reliability (Cronbach's alpha, 0.625, 0.662) and greater variability (Bland & Altman value, 10.5) in total error scores for the classical method and the moment of inertia method between the two illumination conditions when compared to the other two groups. The customized booth demonstrated illumination meeting CIE standards. The total error scores were overestimated by the classical and moment of inertia methods in all groups for room illumination compared with booth illumination, however overestimation was more significant in the diabetes group.

The WISC-III and Raven Coloured Progressive Matrices Test: A Pilot Study of Relationships.

ERIC Educational Resources Information Center

Kluever, Raymond C.; And Others

The relationship between scores on Raven's Coloured Progressive Matrices (CPM) scores and subtest scores and IQs from the Wechsler Intelligence Scale for Children-III (WISC-III) was studied for 28 children aged 6 to 11 years. Subjects had been referred to a university assessment center because they were believed to have exceptional learning…

Accuracy of shade matching performed by colour blind and normal dental students using 3D Master and Vita Lumin shade guides.

PubMed

Vafaee, F; Rakhshan, V; Vafaei, M; Khoshhal, M

2012-03-01

The purpose of this study was to investigate whether 3D Master or VitaLumin shade guides could improve colour selection in individuals with normal and defective colour vision. First, colour perception of 260 dental students was evaluated. Afterwards, 9 colour blind and 9 matched normal subjects tried to detect colours of 10 randomly selected tabs from each kit and the correct/false answers were counted. Of the colour-defective subjects, 47.8% and 33.3% correctly detected the shade using 3D Master and VitaLumin, respectively. These statistics were 62.2% and 42.2% in normal subjects. In normal participants, but not in colour blind ones, 3D Master significantly improved shade matching accuracy compared to VitaLumin.

Clinical and patient reported outcomes of bleaching effectiveness.

PubMed

Klaric Sever, Eva; Budimir, Zrinka; Cerovac, Matea; Stambuk, Mario; Par, Matej; Negovetic Vranic, Dubravka; Tarle, Zrinka

2018-01-01

The objective of this study is to evaluate clinical and patient reported outcomes of different bleaching products. Thirty participants were randomly divided into three bleaching groups (n = 10). Bleaching was performed with high concentrations of hydrogen peroxide (HP) - Boost (40%) and Dash (30%), and with prefabricated splints Bite&White (6% HP). Tooth colour was measured before, immediately after, and 1 and 6 months after the bleaching by using classical shade guide and spectrophotometer. Tooth hypersensitivity was self-rated by patients on the Wong-Baker's face scale. Patient satisfaction was evaluated on a 7-point Likert-type scales that measured perceived performance and importance of different characteristics of bleaching treatment. All products were effective in teeth colour change (ΔE > 3.3), which was significantly higher for Boost (p = .016) and Dash (p = .024) than Bite&White treatment. Perception of hypersensitivity was the highest in Boost group, followed by Dash and Bite&White treatment. Most of the patients were satisfied with final tooth colour, length and comfort during treatment, but were dissatisfied with the stability of bleached tooth colour. Materials with the higher concentrations of bleaching agent demonstrated greater bleaching effectiveness than at-home bleaching product, but also a greater hypersensitivity. Lengthening the treatment process, but achieving a more stable tooth colour may improve the perceived value of a bleaching service.

Sexual dichromatism in frogs: natural selection, sexual selection and unexpected diversity.

PubMed

Bell, Rayna C; Zamudio, Kelly R

2012-12-07

Sexual dichromatism, a form of sexual dimorphism in which males and females differ in colour, is widespread in animals but has been predominantly studied in birds, fishes and butterflies. Moreover, although there are several proposed evolutionary mechanisms for sexual dichromatism in vertebrates, few studies have examined this phenomenon outside the context of sexual selection. Here, we describe unexpectedly high diversity of sexual dichromatism in frogs and create a comparative framework to guide future analyses of the evolution of these sexual colour differences. We review what is known about evolution of colour dimorphism in frogs, highlight alternative mechanisms that may contribute to the evolution of sexual colour differences, and compare them to mechanisms active in other major groups of vertebrates. In frogs, sexual dichromatism can be dynamic (temporary colour change in males) or ontogenetic (permanent colour change in males or females). The degree and the duration of sexual colour differences vary greatly across lineages, and we do not detect phylogenetic signal in the distribution of this trait, therefore frogs provide an opportunity to investigate the roles of natural and sexual selection across multiple independent derivations of sexual dichromatism.

Plain faces are more expressive: comparative study of facial colour, mobility and musculature in primates

PubMed Central

Santana, Sharlene E.; Dobson, Seth D.; Diogo, Rui

2014-01-01

Facial colour patterns and facial expressions are among the most important phenotypic traits that primates use during social interactions. While colour patterns provide information about the sender's identity, expressions can communicate its behavioural intentions. Extrinsic factors, including social group size, have shaped the evolution of facial coloration and mobility, but intrinsic relationships and trade-offs likely operate in their evolution as well. We hypothesize that complex facial colour patterning could reduce how salient facial expressions appear to a receiver, and thus species with highly expressive faces would have evolved uniformly coloured faces. We test this hypothesis through a phylogenetic comparative study, and explore the underlying morphological factors of facial mobility. Supporting our hypothesis, we find that species with highly expressive faces have plain facial colour patterns. The number of facial muscles does not predict facial mobility; instead, species that are larger and have a larger facial nucleus have more expressive faces. This highlights a potential trade-off between facial mobility and colour patterning in primates and reveals complex relationships between facial features during primate evolution. PMID:24850898

Peri-implant soft tissue colour around titanium and zirconia abutments: a prospective randomized controlled clinical study.

PubMed

Cosgarea, Raluca; Gasparik, Cristina; Dudea, Diana; Culic, Bogdan; Dannewitz, Bettina; Sculean, Anton

2015-05-01

To objectively determine the difference in colour between the peri-implant soft tissue at titanium and zirconia abutments. Eleven patients, each with two contralaterally inserted osteointegrated dental implants, were included in this study. The implants were restored either with titanium abutments and porcelain-fused-to-metal crowns, or with zirconia abutments and ceramic crowns. Prior and after crown cementation, multi-spectral images of the peri-implant soft tissues and the gingiva of the neighbouring teeth were taken with a colorimeter. The colour parameters L*, a*, b*, c* and the colour differences ΔE were calculated. Descriptive statistics, including non-parametric tests and correlation coefficients, were used for statistical analyses of the data. Compared to the gingiva of the neighbouring teeth, the peri-implant soft tissue around titanium and zirconia (test group), showed distinguishable ΔE both before and after crown cementation. Colour differences around titanium were statistically significant different (P = 0.01) only at 1 mm prior to crown cementation compared to zirconia. Compared to the gingiva of the neighbouring teeth, statistically significant (P < 0.01) differences were found for all colour parameter, either before or after crown cementation for both abutments; more significant differences were registered for titanium abutments. Tissue thickness correlated positively with c*-values for titanium at 1 mm and 2 mm from the gingival margin. Within their limits, the present data indicate that: (i) The peri-implant soft tissue around titanium and zirconia showed colour differences when compared to the soft tissue around natural teeth, and (ii) the peri-implant soft tissue around zirconia demonstrated a better colour match to the soft tissue at natural teeth than titanium. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Blue-yellow colour vision impairment and cognitive deficits in occasional and dependent stimulant users.

PubMed

Hulka, Lea M; Wagner, Michael; Preller, Katrin H; Jenni, Daniela; Quednow, Boris B

2013-04-01

Specific blue-yellow colour vision impairment has been reported in dependent cocaine users and it was postulated that drug-induced changes in retinal dopamine neurotransmission are responsible. However, it is unclear whether these changes are confined to chronic cocaine users, whether they are specific for dopaminergic stimulants such as cocaine and amphetamine and whether they are related to cognitive functions such as working memory, encoding and consolidation. In 47 occasional and 29 dependent cocaine users, 23 MDMA (commonly known as 'ecstasy') users and 47 stimulant-naive controls, colour vision discrimination was measured with the Lanthony Desaturated Panel D-15 Test and memory performance with the Auditory Verbal Learning Test. Both occasional and dependent cocaine users showed higher colour confusion indices than controls. Users of the serotonergic stimulant MDMA (26%), occasional (30%) and dependent cocaine users (34%) exhibited more frequent blue-yellow colour vision disorders compared to controls (9%). Inferior performance of MDMA users was caused by a subgroup with high amphetamine co-use (55%), while MDMA use alone was not associated with decreased blue-yellow discrimination (0%). Cognitive performance was worse in cocaine users with colour vision disorder compared to users and controls with intact colour vision and both colour vision impairment and cognitive deficits were related to cocaine use. Occasional cocaine and amphetamine use might induce blue-yellow colour vision impairment, whereas the serotonergic stimulant MDMA does not impair colour vision. The association between colour vision impairment and cognitive deficits in cocaine users may reflect that retinal and cerebral dopamine alterations are linked to a certain degree.

Image simulation and assessment of the colour and spatial capabilities of the Colour and Stereo Surface Imaging System (CaSSIS) on the ExoMars Trace Gas Orbiter

USGS Publications Warehouse

Tornabene, Livio L.; Seelos, Frank P.; Pommerol, Antoine; Thomas, Nicolas; Caudill, Christy M.; Becerra, Patricio; Bridges, John C.; Byrne, Shane; Cardinale, Marco; Chojnacki, Matthew; Conway, Susan J.; Cremonese, Gabriele; Dundas, Colin M.; El-Maarry, M. R.; Fernando, Jennifer; Hansen, Candice J.; Hansen, Kayle; Harrison, Tanya N.; Henson, Rachel; Marinangeli, Lucia; McEwen, Alfred S.; Pajola, Maurizio; Sutton, Sarah S.; Wray, James J.

2018-01-01

This study aims to assess the spatial and visible/near-infrared (VNIR) colour/spectral capabilities of the 4-band Colour and Stereo Surface Imaging System (CaSSIS) aboard the ExoMars 2016 Trace Grace Orbiter (TGO). The instrument response functions for the CaSSIS imager was used to resample spectral libraries, modelled spectra and to construct spectrally (i.e., in I/F space) and spatially consistent simulated CaSSIS image cubes of various key sites of interest and for ongoing scientific investigations on Mars. Coordinated datasets from Mars Reconnaissance Orbiter (MRO) are ideal, and specifically used for simulating CaSSIS. The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) provides colour information, while the Context Imager (CTX), and in a few cases the High-Resolution Imaging Science Experiment (HiRISE), provides the complementary spatial information at the resampled CaSSIS unbinned/unsummed pixel resolution (4.6 m/pixel from a 400-km altitude). The methodology used herein employs a Gram-Schmidt spectral sharpening algorithm to combine the ∼18–36 m/pixel CRISM-derived CaSSIS colours with I/F images primarily derived from oversampled CTX images. One hundred and eighty-one simulated CaSSIS 4-colour image cubes (at 18–36 m/pixel) were generated (including one of Phobos) based on CRISM data. From these, thirty-three “fully”-simulated image cubes of thirty unique locations on Mars (i.e., with 4 colour bands at 4.6 m/pixel) were made. All simulated image cubes were used to test both the colour capabilities of CaSSIS by producing standard colour RGB images, colour band ratio composites (CBRCs) and spectral parameters. Simulated CaSSIS CBRCs demonstrated that CaSSIS will be able to readily isolate signatures related to ferrous (Fe2+) iron- and ferric (Fe3+) iron-bearing deposits on the surface of Mars, ices and atmospheric phenomena. Despite the lower spatial resolution of CaSSIS when compared to HiRISE, the results of this work demonstrate that CaSSIS will not only compliment HiRISE-scale studies of various geological and seasonal phenomena, it will also enhance them by providing additional colour and geologic context through its wider and longer full-colour coverage (∼9.4×50">∼9.4×50∼9.4×50 km), and its increased sensitivity to iron-bearing materials from its two IR bands (RED and NIR). In a few examples, subtle surface changes that were not easily detected by HiRISE were identified in the simulated CaSSIS images. This study also demonstrates the utility of the Gram-Schmidt spectral pan-sharpening technique to extend VNIR colour/spectral capabilities from a lower spatial resolution colour/spectral dataset to a single-band or panchromatic image greyscale image with higher resolution. These higher resolution colour products (simulated CaSSIS or otherwise) are useful as means to extend both geologic context and mapping of datasets with coarser spatial resolutions. The results of this study indicate that the TGO mission objectives, as well as the instrument-specific mission objectives, will be achievable with CaSSIS.

Structure and optical function of amorphous photonic nanostructures from avian feather barbs: a comparative small angle X-ray scattering (SAXS) analysis of 230 bird species

PubMed Central

Saranathan, Vinodkumar; Forster, Jason D.; Noh, Heeso; Liew, Seng-Fatt; Mochrie, Simon G. J.; Cao, Hui; Dufresne, Eric R.; Prum, Richard O.

2012-01-01

Non-iridescent structural colours of feathers are a diverse and an important part of the phenotype of many birds. These colours are generally produced by three-dimensional, amorphous (or quasi-ordered) spongy β-keratin and air nanostructures found in the medullary cells of feather barbs. Two main classes of three-dimensional barb nanostructures are known, characterized by a tortuous network of air channels or a close packing of spheroidal air cavities. Using synchrotron small angle X-ray scattering (SAXS) and optical spectrophotometry, we characterized the nanostructure and optical function of 297 distinctly coloured feathers from 230 species belonging to 163 genera in 51 avian families. The SAXS data provided quantitative diagnoses of the channel- and sphere-type nanostructures, and confirmed the presence of a predominant, isotropic length scale of variation in refractive index that produces strong reinforcement of a narrow band of scattered wavelengths. The SAXS structural data identified a new class of rudimentary or weakly nanostructured feathers responsible for slate-grey, and blue-grey structural colours. SAXS structural data provided good predictions of the single-scattering peak of the optical reflectance of the feathers. The SAXS structural measurements of channel- and sphere-type nanostructures are also similar to experimental scattering data from synthetic soft matter systems that self-assemble by phase separation. These results further support the hypothesis that colour-producing protein and air nanostructures in feather barbs are probably self-assembled by arrested phase separation of polymerizing β-keratin from the cytoplasm of medullary cells. Such avian amorphous photonic nanostructures with isotropic optical properties may provide biomimetic inspiration for photonic technology. PMID:22572026

The static quark potential from the gauge independent Abelian decomposition

NASA Astrophysics Data System (ADS)

Cundy, Nigel; Cho, Y. M.; Lee, Weonjong; Leem, Jaehoon

2015-06-01

We investigate the relationship between colour confinement and the gauge independent Cho-Duan-Ge Abelian decomposition. The decomposition is defined in terms of a colour field n; the principle novelty of our study is that we have used a unique definition of this field in terms of the eigenvectors of the Wilson Loop. This allows us to establish an equivalence between the path-ordered integral of the non-Abelian gauge fields and an integral over an Abelian restricted gauge field which is tractable both theoretically and numerically in lattice QCD. We circumvent path ordering without requiring an additional path integral. By using Stokes' theorem, we can compute the Wilson Loop in terms of a surface integral over a restricted field strength, and show that the restricted field strength may be dominated by certain structures, which occur when one of the quantities parametrising the colour field n winds itself around a non-analyticity in the colour field. If they exist, these structures will lead to an area law scaling for the Wilson Loop and provide a mechanism for quark confinement. Unlike most studies of confinement using the Abelian decomposition, we do not rely on a dual-Meissner effect to create the inter-quark potential. We search for these structures in quenched lattice QCD. We perform the Abelian decomposition, and compare the electric and magnetic fields with the patterns expected theoretically. We find that the restricted field strength is dominated by objects which may be peaks of a single lattice spacing in size or extended string-like lines of electromagnetic flux. The objects are not isolated monopoles, as they generate electric fields in addition to magnetic fields, and the fields are not spherically symmetric, but may be either caused by a monopole/anti-monopole condensate, some other types of topological objects, or a combination of these. Removing these peaks removes the area law scaling of the string tension, suggesting that they are responsible for confinement.

Colour preferences in nest-building zebra finches.

PubMed

Muth, Felicity; Steele, Matthew; Healy, Susan D

2013-10-01

Some bird species are selective in the materials they choose for nest building, preferring, for example, materials of one colour to others. However, in many cases the cause of these preferences is not clear. One of those species is the zebra finch, which exhibits strong preferences for particular colours of nest material. In an attempt to determine why these birds strongly prefer one colour of material over another, we compared the preferences of paired male zebra finches for nest material colour with their preferences for food of the same colours. We found that birds did indeed prefer particular colours of nest material (in most cases blue) but that they did not generally prefer food of one colour over the other colours. It appears, then, that a preference for one colour or another of nest material is specific to the nest-building context. This article is part of a Special Issue entitled: insert SI title. Copyright © 2013 Elsevier B.V. All rights reserved.

Where have all the blue flowers gone: pollinator responses and selection on flower colour in New Zealand Wahlenbergia albomarginata.

PubMed

Campbell, D R; Bischoff, M; Lord, J M; Robertson, A W

2012-02-01

Although pollinators are thought to select on flower colour, few studies have experimentally decoupled effects of colour from correlated traits on pollinator visitation and pollen transfer. We combined selection analysis and phenotypic manipulations to measure the effect of petal colour on visitation and pollen export at two spatial scales in Wahlenbergia albomarginata. This species is representative of many New Zealand alpine herbs that have secondarily evolved white or pale flowers. The major pollinators, solitary bees, exerted phenotypic selection on flower size but not colour, quantified by bee vision. When presented with manipulated flowers, bees visited flowers painted blue to resemble a congener over white flowers in large, but not small, experimental arrays. Pollen export was higher for blue flowers in large arrays. Pollinator preference does not explain the pale colouration of W. albomarginata, as commonly hypothesized. Absence of bright blue could be driven instead by indirect selection of correlated characters. © 2011 The Authors. Journal of Evolutionary Biology © 2011 European Society For Evolutionary Biology.

[Digital processing and evaluation of ultrasound images].

PubMed

Borchers, J; Klews, P M

1993-10-01

With the help of workstations and PCs, on-site image processing has become possible. If the images are not available in digital form the video signal has to be A/D converted. In the case of colour images the colour channels R (red), G (green) and B (blue) have to be digitized separately. "Truecolour" imaging calls for an 8 bit resolution per channel, leading to 24 bits per pixel. Out of a pool of 2(24) possible values only the relevant 128 gray values and 64 shades of red and blue respectively needed for a colour-coded ultrasound image have to be isolated. Digital images can be changed and evaluated with the help of readily available image evaluation programmes. It is mandatory that during image manipulation the gray scale and colour pixels and LUTs (Look-Up-Table) must be worked on separately. Using relatively simple LUT manipulations astonishing image improvements are possible. Application of simple mathematical operations can lead to completely new clinical results. For example, by subtracting two consecutive colour flow images in time and special LUT operations, local acceleration of blood flow can be visualized (Colour Acceleration Imaging).

Color changes kinetics during deep fat frying of carrot slice

NASA Astrophysics Data System (ADS)

Salehi, Fakhreddin

2018-05-01

Heat and mass transfer phenomena take place during frying cause physicochemical changes, which affect the colour and surface of the fried products. The effect of frying temperature on the colour changes and heat transfer during deep fat frying of carrot has been investigated. The colour scale parameters redness (a*), yellowness (b*) and lightness (L*), and color change intensity (ΔE) were used to estimate colour changes during frying as a function of oil temperature. L* value of fried carrot decreased during frying. The redness of fried carrot decreased during the early stages of frying, while it increased afterwards (become more red). A first-order kinetic equation was used for each one of the three colour parameters, in which the rate constant is a function of oil temperatures. The results showed that oil temperature has a significant effect on the colour parameters. Different kinetic models were used to fit the experimental data and the results revealed that the quadratic model was the most suitable to describe the color change intensity (ΔE) (R > 0.96). Center temperature of carrot slice increased with increase in oil temperature and time during frying.

Comparison of the psychometric properties of 3 pain scales used in the pediatric emergency department: Visual Analogue Scale, Faces Pain Scale-Revised, and Colour Analogue Scale.

PubMed

Le May, Sylvie; Ballard, Ariane; Khadra, Christelle; Gouin, Serge; Plint, Amy C; Villeneuve, Edith; Mâsse, Benoit; Tsze, Daniel S; Neto, Gina; Drendel, Amy L; Auclair, Marie-Christine; McGrath, Patrick J; Ali, Samina

2018-03-30

Appropriate pain measurement relies on the use of valid, reliable tools. The aim of this study was to determine and compare the psychometric properties of 3 self-reported pain scales commonly used in the pediatric emergency department (ED). The inclusion criteria were children aged 6 to 17 years presenting to the ED with a musculoskeletal injury and self-reported pain scores ≥30 mm on the mechanical Visual Analogue Scale (VAS). Self-reported pain intensity was assessed using the mechanical VAS, Faces Pain Scale-Revised (FPS-R), and Colour Analogue Scale (CAS). Convergent validity was assessed by Pearson correlations and the Bland-Altman method; responsiveness to change was assessed using paired sample t tests and standardized mean responses; and reliability was estimated using relative and absolute indices. A total of 456 participants were included, with a mean age of 11.9 years ± 2.7 and a majority were boys (252/456, 55.3%). Correlations between each pair of scales were 0.78 (VAS/FPS-R), 0.92 (VAS/CAS), and 0.79 (CAS/FPS-R). Limits of agreement (95% confidence interval) were -3.77 to 2.33 (VAS/FPS-R), -1.74 to 1.75 (VAS/CAS), and -2.21 to 3.62 (CAS/FPS-R). Responsiveness to change was demonstrated by significant differences in mean pain scores among the scales (P < 0.0001). Intraclass correlation coefficient and coefficient of repeatability estimates suggested acceptable reliability for the 3 scales at, respectively, 0.79 and ±2.29 (VAS), 0.82 and ±2.07 (CAS), and 0.76 and ±2.82 (FPS-R). The scales demonstrated good psychometric properties for children with acute pain in the ED. The VAS and CAS showed a strong convergent validity, whereas FPS-R was not in agreement with the other scales.

The Carnegie Chicago Hubble Program: The Mid-Infrared Colours of Cepheids and the Effect of Metallicity on the CO Band-Head at 4.6 Micron

NASA Technical Reports Server (NTRS)

Scowcroft, Victoria; Seibert, Mark; Freedman, Wendy L.; Beaton, Rachael L.; Madore, Barry F.; Monson, Andrew J.; Rich, Jeffery A.; Rigby, Jane R.

2016-01-01

We compare mid-infrared (IR) 3.6 and 4.5 micron Warm Spitzer observations for Cepheids in the Milky Way and the Large and Small Magellanic Clouds. Using models, we explore in detail the effect of the CO rotation-vibration band-head at 4.6 micron on the mid-IR photometry. We confirm the temperature sensitivity of the CO band-head at 4.6 micron and find no evidence for an effect at 3.6 micron. We compare the ([3.6]-[4.5]) period-colour relations in the MW, LMC and SMC. The slopes of the period-colour relations for the three galaxies are in good agreement, but there is a trend in zero-point with metallicity, with the lowest metallicity Cepheids having redder mid-IR colours. Finally, we present a colour-[Fe/H] relation based on published spectroscopic metallicities. This empirical relation, calibrated to the metallicity system of Genovali et al., demonstrates that the ([3.6]-[4.5]) colour provides a reliable metallicity indicator for Cepheids, with a precision comparable to current spectroscopic determinations.

Supra-galactic colour patterns in globular cluster systems

NASA Astrophysics Data System (ADS)

Forte, Juan C.

2017-07-01

An analysis of globular cluster systems associated with galaxies included in the Virgo and Fornax Hubble Space Telescope-Advanced Camera Surveys reveals distinct (g - z) colour modulation patterns. These features appear on composite samples of globular clusters and, most evidently, in galaxies with absolute magnitudes Mg in the range from -20.2 to -19.2. These colour modulations are also detectable on some samples of globular clusters in the central galaxies NGC 1399 and NGC 4486 (and confirmed on data sets obtained with different instruments and photometric systems), as well as in other bright galaxies in these clusters. After discarding field contamination, photometric errors and statistical effects, we conclude that these supra-galactic colour patterns are real and reflect some previously unknown characteristic. These features suggest that the globular cluster formation process was not entirely stochastic but included a fraction of clusters that formed in a rather synchronized fashion over large spatial scales, and in a tentative time lapse of about 1.5 Gy at redshifts z between 2 and 4. We speculate that the putative mechanism leading to that synchronism may be associated with large scale feedback effects connected with violent star-forming events and/or with supermassive black holes.

The handicap of abnormal colour vision.

PubMed

Cole, Barry L

2004-07-01

All people with abnormal colour vision, except for a few mildly affected deuteranomals, report that they experience problems with colour in everyday life and at work. Contemporary society presents them with increasing problems because colour is now so widely used in printed materials and in computer displays. Equal opportunity law gives them protection against unfair discrimination in employment, so a decision to exclude a person from employment on the grounds of abnormal colour vision must now be well supported by good evidence and sound argument. This paper reviews the investigations that have contributed to understanding the nature and consequences of the problems they have. All those with abnormal colour vision are at a disadvantage with comparative colour tasks that involve precise matching of colours or discrimination of fine colour differences either because of their loss of colour discrimination or anomalous perception of metamers. The majority have problems when colour is used to code information, in man-made colour codes and in naturally occurring colour codes that signal ripeness of fruit, freshness of meat or illness. They can be denied the benefit of colour to mark out objects and organise complex visual displays. They may be unreliable when a colour name is used as an identifier. They are slower and less successful in search when colour is an attribute of the target object or is used to organise the visual display. Because those with the more severe forms of abnormal colour vision perceive a very limited gamut of colours, they are at a disadvantage in the pursuit and appreciation of those forms of art that use colour.

Illumination preference, illumination constancy and colour discrimination by bumblebees in an environment with patchy light.

PubMed

Arnold, Sarah E J; Chittka, Lars

2012-07-01

Patchy illumination presents foraging animals with a challenge, as the targets being sought may appear to vary in colour depending on the illumination, compromising target identification. We sought to explore how the bumblebee Bombus terrestris copes with tasks involving flower colour discrimination under patchy illumination. Light patches varied between unobscured daylight and leaf-shade, as a bee might encounter in and around woodland. Using a flight arena and coloured filters, as well as one or two different colours of artificial flower, we quantified how bees chose to forage when presented with foraging tasks under patchy illumination. Bees were better at discriminating a pair of similar colours under simulated unobscured daylight illumination than when foraging under leaf-shade illumination. Accordingly, we found that bees with prior experience of simulated daylight but not leaf-shade illumination initially preferred to forage in simulated daylight when all artificial flowers contained rewards as well as when only one colour was rewarding, whereas bees with prior experience of both illuminants did not exhibit this preference. Bees also switched between illuminants less than expected by chance. This means that bees prefer illumination conditions with which they are familiar, and in which rewarding flower colours are easily distinguishable from unrewarding ones. Under patchy illumination, colour discrimination performance was substantially poorer than in homogenous light. The bees' abilities at coping with patchy light may therefore impact on foraging behaviour in the wild, particularly in woodlands, where illumination can change over short spatial scales.

Filling schemes of silver dots inkjet-printed on pixelated nanostructured surfaces

NASA Astrophysics Data System (ADS)

Alan, Sheida; Jiang, Hao; Shahbazbegian, Haleh; Patel, Jasbir N.; Kaminska, Bozena

2017-03-01

Recently, our group demonstrated an inkjet-based technique to enable high-throughput, versatile and full-colour printing of structural colours on generic pixelated nanostructures, termed as molded ink on nanostructured surfaces. The printed colours are controlled by the area of printed silver on the pixelated red, green and blue polymer nanostructure arrays. This paper investigates the behaviour of jetted silver ink droplets on nanostructured surfaces and the microscale dot patterns implemented during printing process, for achieving accurate and consistent colours in the printed images. The surface wettability and the schemes of filling silver dots inside the subpixels are crucial to the quality of printed images. Several related concepts and definitions are introduced, such as filling ratio, full dots per subpixel (DPSP), number of printable colours, colour leaking and dot merging. In our experiments, we first chemically modified the surface to control the wettability and dot size. From each type of modified surface, various filling schemes were experimented and the printed results were evaluated with comprehensive considerations on the number of printable colours and the negative effects of colour leaking and dot merging. Rational selection of the best filling scheme resulted in a 2-line filling scheme using 20 μm dot spacing and line spacing capable of printing 9261 different colours with 121 pixel per inch display resolution, on low-wettability surface. This study is of vital importance for scaling up the printing technique in industrial applications and provides meaningful insights for inkjet-printing on nanostructures.

In Situ Visualization of Block Copolymer Self‐Assembly in Organic Media by Super‐Resolution Fluorescence Microscopy

PubMed Central

Boott, Charlotte E.; Laine, Romain F.; Mahou, Pierre; Finnegan, John R.; Leitao, Erin M.

2015-01-01

Abstract Analytical methods that enable visualization of nanomaterials derived from solution self‐assembly processes in organic solvents are highly desirable. Herein, we demonstrate the use of stimulated emission depletion microscopy (STED) and single molecule localization microscopy (SMLM) to map living crystallization‐driven block copolymer (BCP) self‐assembly in organic media at the sub‐diffraction scale. Four different dyes were successfully used for single‐colour super‐resolution imaging of the BCP nanostructures allowing micelle length distributions to be determined in situ. Dual‐colour SMLM imaging was used to measure and compare the rate of addition of red fluorescent BCP to the termini of green fluorescent seed micelles to generate block comicelles. Although well‐established for aqueous systems, the results highlight the potential of super‐resolution microscopy techniques for the interrogation of self‐assembly processes in organic media. PMID:26477697

Colour Matching in Decorative Thermally Sprayed Glass Coatings

NASA Astrophysics Data System (ADS)

Poirier, Thierry; Bertrand, Pierre; Coddet, Christian

2013-02-01

Coloured coatings were obtained on steel by plasma spraying without severe in-flight alteration of pigments, taking profit of the low thermal conductivity of the glassy matrix of glaze particles. Colour matching was studied by mixing 3 different glazes, comparing Grassmann and Kubelka-Munk based algorithms. Results suggest that the latter method should be preferred upon Grassmann method, particularly when the light absorption/dispersion ratios of coloured feedstocks are very different.

The perception of isoluminant coloured stimuli of amblyopic eye and defocused eye

NASA Astrophysics Data System (ADS)

Krumina, Gunta; Ozolinsh, Maris; Ikaunieks, Gatis

2008-09-01

In routine eye examination the visual acuity usually is determined using standard charts with black letters on a white background, however contrast and colour are important characteristics of visual perception. The purpose of research was to study the perception of isoluminant coloured stimuli in the cases of true and simulated amlyopia. We estimated difference in visual acuity with isoluminant coloured stimuli comparing to that for high contrast black-white stimuli for true amblyopia and simulated amblyopia. Tests were generated on computer screen. Visual acuity was detected using different charts in two ways: standard achromatic stimuli (black symbols on a white background) and isoluminant coloured stimuli (white symbols on a yellow background, grey symbols on blue, green or red background). Thus isoluminant tests had colour contrast only but had no luminance contrast. Visual acuity evaluated with the standard method and colour tests were studied for subjects with good visual acuity, if necessary using the best vision correction. The same was performed for subjects with defocused eye and with true amblyopia. Defocus was realized with optical lenses placed in front of the normal eye. The obtained results applying the isoluminant colour charts revealed worsening of the visual acuity comparing with the visual acuity estimated with a standard high contrast method (black symbols on a white background).

Colour image segmentation using unsupervised clustering technique for acute leukemia images

NASA Astrophysics Data System (ADS)

Halim, N. H. Abd; Mashor, M. Y.; Nasir, A. S. Abdul; Mustafa, N.; Hassan, R.

2015-05-01

Colour image segmentation has becoming more popular for computer vision due to its important process in most medical analysis tasks. This paper proposes comparison between different colour components of RGB(red, green, blue) and HSI (hue, saturation, intensity) colour models that will be used in order to segment the acute leukemia images. First, partial contrast stretching is applied on leukemia images to increase the visual aspect of the blast cells. Then, an unsupervised moving k-means clustering algorithm is applied on the various colour components of RGB and HSI colour models for the purpose of segmentation of blast cells from the red blood cells and background regions in leukemia image. Different colour components of RGB and HSI colour models have been analyzed in order to identify the colour component that can give the good segmentation performance. The segmented images are then processed using median filter and region growing technique to reduce noise and smooth the images. The results show that segmentation using saturation component of HSI colour model has proven to be the best in segmenting nucleus of the blast cells in acute leukemia image as compared to the other colour components of RGB and HSI colour models.

Reviews Book: At Home: A Short History of Private Life Book: The Story of Mathematics Book: Time Travel: A Writer's Guide to the Real Science of Plausible Time Travel Equipment: Rotational Inertial Wands DVD: Planets Book: The Fallacy of Fine-Tuning Equipment: Scale with Dial Equipment: Infrared Thermometers Book: 300 Science and History Projects Book: The Nature of Light and Colour in the Open Air Equipment: Red Tide Spectrometer Web Watch

NASA Astrophysics Data System (ADS)

2011-09-01

WE RECOMMEND The Story of Mathematics Book shows the link between maths and physics Time Travel: A Writer's Guide to the Real Science of Plausible Time Travel Book explains how to write good time-travelling science fiction Rotational Inertial Wands Wands can help explore the theory of inertia Infrared Thermometers Kit measures temperature differences Red Tide Spectrometer Spectrometer gives colour spectra WORTH A LOOK At Home: A Short History of Private Life Bryson explores the history of home life The Fallacy of Fine-Tuning Book wades into the science/religion debate Scale with Dial Cheap scales can be turned into Newton measuring scales 300 Science History Projects Fun science projects for kids to enjoy The Nature of Light and Colour in the Open Air Text looks at fascinating optical effects HANDLE WITH CARE Planets DVD takes a trip through the solar system WEB WATCH Websites offer representations of nuclear chain reactions

Colour bio-factories: Towards scale-up production of anthocyanins in plant cell cultures.

PubMed

Appelhagen, Ingo; Wulff-Vester, Anders Keim; Wendell, Micael; Hvoslef-Eide, Anne-Kathrine; Russell, Julia; Oertel, Anne; Martens, Stefan; Mock, Hans-Peter; Martin, Cathie; Matros, Andrea

2018-06-08

Anthocyanins are widely distributed, glycosylated, water-soluble plant pigments, which give many fruits and flowers their red, purple or blue colouration. Their beneficial effects in a dietary context have encouraged increasing use of anthocyanins as natural colourants in the food and cosmetic industries. However, the limited availability and diversity of anthocyanins commercially have initiated searches for alternative sources of these natural colourants. In plants, high-level production of secondary metabolites, such as anthocyanins, can be achieved by engineering of regulatory genes as well as genes encoding biosynthetic enzymes. We have used tobacco lines which constitutively produce high levels of cyanidin 3-O-rutinoside, delphinidin 3-O-rutinoside or a novel anthocyanin, acylated cyanidin 3-O-(coumaroyl) rutinoside to generate cell suspension cultures. The cell lines are stable in their production rates and superior to conventional plant cell cultures. Scale-up of anthocyanin production in small scale fermenters has been demonstrated. The cell cultures have also proven to be a suitable system for production of 13 C-labelled anthocyanins. Our method for anthocyanin production is transferable to other plant species, such as Arabidopsis thaliana, demonstrating the potential of this approach for making a wide range of highly-decorated anthocyanins. The tobacco cell cultures represent a customisable and sustainable alternative to conventional anthocyanin production platforms and have considerable potential for use in industrial and medical applications of anthocyanins. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Satisfaction with appearance and the desired treatment to improve aesthetics.

PubMed

Al-Zarea, Bader K

2013-01-01

Objective. To identify participants' satisfaction with appearance and the desired treatment to improve aesthetics. Materials and Methods. 220 participants (127 males and 93 females, mean age = 21.4 ± 1.5 years) were recruited into the study. A structured questionnaire was used to assess patients' satisfaction with appearance and what treatment they desire to improve aesthetics. Participants scored the level of satisfaction with appearance using visual analogue scale. Results. The VAS mean score of satisfaction with general appearance was 6.8 ± 2.3. Half participants were dissatisfied with tooth appearance and 65.9% were dissatisfied with tooth colour. Higher VAS scores were associated with higher desire for all treatments that improve tooth appearance (P < .05). Dissatisfaction with tooth appearance increased with increased dissatisfaction with teeth colour, feeling of poor tooth alignment, presence of fractured anterior teeth, and increased desire for orthodontic, crowns, and dentures treatments (P < .05). Dissatisfaction with tooth colour was associated with increased desire for tooth whitening and tooth coloured fillings (P < .05). Conclusions. Participants had high levels of dissatisfaction with tooth appearance and tooth colour. Dissatisfaction with tooth colour contributed to the increased dissatisfaction with tooth appearance. Dissatisfaction with tooth appearance, colour, alignment, and condition was significantly related to high desire for aesthetic treatments.

Human colour in mate choice and competition.

PubMed

Rowland, Hannah M; Burriss, Robert P

2017-07-05

The colour of our skin and clothing affects how others perceive us and how we behave. Human skin colour varies conspicuously with genetic ancestry, but even subtle changes in skin colour due to diet, blood oxygenation and hormone levels influence social perceptions. In this review, we describe the theoretical and empirical frameworks in which human colour is researched. We explore how subtle skin colour differences relate to judgements of health and attractiveness. Also, because humans are one of the few organisms able to manipulate their apparent colour, we review how cosmetics and clothing are implicated in courtship and competition, both inside the laboratory and in the real world. Research on human colour is in its infancy compared with human psychophysics and colour research in non-human animals, and hence we present best-practice guidelines for methods and reporting, which we hope will improve the validity and reproducibility of studies on human coloration.This article is part of the themed issue 'Animal coloration: production, perception, function and application'. © 2017 The Author(s).

Angle-independent pH-sensitive composites with natural gyroid structure

PubMed Central

Xue, Ruiyang; Zhang, Wang; Sun, Peng; Zada, Imran; Guo, Cuiping; Liu, Qinglei; Gu, Jiajun; Su, Huilan; Zhang, Di

2017-01-01

pH sensor is an important and practical device with a wide application in environmental protection field and biomedical industries. An efficient way to enhance the practicability of intelligent polymer composed pH sensor is to subtilize the three-dimensional microstructure of the materials, adding measurable features to visualize the output signal. In this work, C. rubi wing scales were combined with pH-responsive smart polymer polymethylacrylic acid (PMAA) through polymerization to achieve a colour-tunable pH sensor with nature gyroid structure. Morphology and reflection characteristics of the novel composites, named G-PMAA, are carefully investigated and compared with the original biotemplate, C. rubi wing scales. The most remarkable property of G-PMAA is a single-value corresponding relationship between pH value and the reflection peak wavelength (λmax), with a colour distinction degree of 18 nm/pH, ensuring the accuracy and authenticity of the output. The pH sensor reported here is totally reversible, which is able to show the same results after several detection circles. Besides, G-PMAA is proved to be not influenced by the detection angle, which makes it a promising pH sensor with superb sensitivity, stability, and angle-independence. PMID:28165044

Colour changes in Labeo rohita (Ham.) due to pigment translocation in melanophores, on exposure to municipal wastewater of Tung Dhab drain, Amritsar, India.

PubMed

Kaur, Rajbir; Dua, Anish

2015-03-01

The present study was aimed to evaluate the effect of municipal wastewater of Tung Dhab drain on morphology of scale melanophores in freshwater fish Labeo rohita (Ham.). Chronic, non-renewal toxicity tests were performed with sub lethal concentrations (17.7, 26.6 and 35.4%) of wastewater for exposure durations of 15, 30 and 60 days. Recovery experiments were also performed for duration of 60 days. The scales were removed, processed and diameters of melanophores were measured using an ocular micrometer. The results showed concentration and duration dependent changes in melanophore morphology (size and dendricity) in experimental fish as compared to control fish. The values of mean melanophore size index (MMSI) varied from 5.37 ± 0.49 (17.7%) to 12.12 ± 0.81 (35.5%) in comparison to control values of 4.32 ± 0.32 and 4.55 ± 0.29 for 15 and 60 days respectively. The recovery experiments suggested that observed dark colouration due to pigment translocation is reversible, even after chronic exposure for 60 days. Copyright © 2015 Elsevier B.V. All rights reserved.

Colour correct: the interactive effects of food label nutrition colouring schemes and food category healthiness on health perceptions.

PubMed

Nyilasy, Gergely; Lei, Jing; Nagpal, Anish; Tan, Joseph

2016-08-01

The purpose of the present study was to examine the effects of food label nutrition colouring schemes in interaction with food category healthiness on consumers' perceptions of food healthiness. Three streams of colour theory (colour attention, colour association and colour approach-avoidance) in interaction with heuristic processing theory provide consonant predictions and explanations for the underlying psychological processes. A 2 (food category healthiness: healthy v. unhealthy)×3 (food label nutrient colouring schemes: healthy=green, unhealthy=red (HGUR) v. healthy=red, unhealthy=green (HRUG) v. no colour (control)) between-subjects design was used. The research setting was a randomised-controlled experiment using varying formats of food packages and nutritional information colouring. Respondents (n 196) sourced from a national consumer panel, USA. The findings suggest that, for healthy foods, the nutritional colouring schemes reduced perceived healthiness, irrespective of which nutrients were coloured red or green (healthinesscontrol=4·86; healthinessHGUR=4·10; healthinessHRUG=3·70). In contrast, for unhealthy foods, there was no significant difference in perceptions of food healthiness when comparing different colouring schemes against the control. The results make an important qualification to the common belief that colour coding can enhance the correct interpretation of nutrition information and suggest that this incentive may not necessarily support healthier food choices in all situations.

Working memory in children and adolescents with Down syndrome: evidence from a colour memory experiment.

PubMed

Laws, Glynis

2002-03-01

This paper reports information on the visual and verbal short-term memory of individuals with Down syndrome. Colour memory in 16 children and adolescents with Down syndrome was compared with that of 16 typically developing children matched for receptive vocabulary. It was suggested that focal colours should be remembered more successfully than non-focal colours on the basis that the former could be remembered using a verbal recoding strategy. However, children with Down syndrome, for whom a deficit in verbal short-term memory makes the use of such a strategy unlikely, should remember focal and non-focal colours equally well. More importantly, if individuals with Down syndrome have more developed visual memory abilities than control children, they should outperform them in recognising non-focal colours. Although the group with Down syndrome demonstrated significantly better Corsi blocks performance than controls, and displayed similar levels of colour knowledge, no advantage for colour memory was found. Non-focal colours were remembered by individuals with Down syndrome as successfully as focal colours but there was no indication of a visual memory advantage over controls. Focal colours were remembered significantly more successfully than non-focal colours by the typically developing children. Their focal colour memory was significantly related to digit span, but only Corsi span was related to focal colour memory in the group with Down syndrome.

The influence of slope and peatland vegetation type on riverine dissolved organic carbon and water colour at different scales.

PubMed

Parry, L E; Chapman, P J; Palmer, S M; Wallage, Z E; Wynne, H; Holden, J

2015-09-15

Peatlands are important sources of fluvial carbon. Previous research has shown that riverine dissolved organic carbon (DOC) concentrations are largely controlled by soil type. However, there has been little work to establish the controls of riverine DOC within blanket peatlands that have not undergone major disturbance from drainage or burning. A total of 119 peatland catchments were sampled for riverine DOC and water colour across three drainage basins during six repeated sampling campaigns. The topographic characteristics of each catchment were determined from digital elevation models. The dominant vegetation cover was mapped using 0.5m resolution colour infrared aerial images, with ground-truthed validation revealing 82% accuracy. Forward and backward stepwise regression modelling showed that mean slope was a strong (and negative) determinant of DOC and water colour in blanket peatland river waters. There was a weak role for plant functional type in determining DOC and water colour. At the basin scale, there were major differences between the models depending on the basin. The dominance of topographic predictors of DOC found in our study, combined with a weaker role of vegetation type, paves the way for developing improved planning tools for water companies operating in peatland catchments. Using topographic data and aerial imagery it will be possible to predict which tributaries will typically yield lower DOC concentrations and which are therefore more suitable and cost-effective as raw water intakes. Copyright © 2015 Elsevier B.V. All rights reserved.

The Gradual Transformation of Historical Situations: Understanding "Change and Continuity" through Colours and Timelines

ERIC Educational Resources Information Center

Vella, Yosanne

2011-01-01

The small-scale research that Yosanne Vella reports in this article was driven by concern to help pupils develop "big picture" visions of the past and to engage effectively with the idea of change as a process rather than an event. The strategy that she adopts--asking groups of students to colour in a timeline recording their judgement…

Colour blindness in everyday life and car driving.

PubMed

Tagarelli, Antonio; Piro, Anna; Tagarelli, Giuseppe; Lantieri, Pasquale Bruno; Risso, Domenico; Olivieri, Rosario Luciano

2004-08-01

The aim of the present work was to ascertain, through the administration of a psychosocial questionnaire, the difficulties that subjects with defective colour vision experience in carrying out everyday tasks and work, including driving a car with a driver's licence held for no more than 3 years. Subjects with defective colour vision (n = 151) and subjects with normal vision (n = 302) completed a psychosocial questionnaire regarding the difficulties associated with congenital colour vision deficiency in daily life, work and driving a car. Subjects were diagnosed as colour-blind using the Ishihara test. Statistically significant differences between the two samples were found for daily life activities. Subjects with defective colour vision preferred daytime driving. At night, subjects with defective colour vision had difficulty identifying reflectors on the road and the rear signal lights of cars ahead of them. Colour-blind Calabrian subjects admitted to experiencing colour-related difficulties with a wide range of occupational tasks and leisure pursuits. In particular, colour-blind Calabrian subjects preferred daytime driving, and fewer drove regularly, compared to orthochromatics, who were indifferent to night or daytime driving.

Comparing visual and objective skin assessment with pressure injury risk.

PubMed

Borzdynski, Caroline J; McGuiness, William; Miller, Charne

2016-08-01

Contemporary approaches to pressure injury (PI) risk identification rely on the use of risk assessment tools and visual skin assessment. Objective biophysical measures that assess skin hydration, melanin, erythema and lipids have not been traditionally used in PI risk; however, these may prove useful as a risk assessment tool. The relationship between subjective visual assessments of skin condition, biophysical measures and PI risk warrants investigation. This study used a descriptive correlational design to examine the relationship between measures of skin hydration, colour (melanin and erythema) and lipids at PI-prone areas amongst geriatric persons (n = 38), obtained using biophysical skin measures and visual skin assessment. Twice daily measures of epidermal hydration, colour and lipids were assessed using the SD202 Skin Diagnostic (Courage + Khazaka GmBH, Cologne, Germany) over pressure-prone areas of the body of study participants over seven consecutive days. Concurrent visual assessment of skin hydration and colour was performed. Results obtained using the SD202 Skin Diagnostic were compared with results gathered from visual assessment and examined for their association with participants' PI risk based on scores of the Norton Risk Assessment Scale. While epidermal hydration and skin colour reading scores did not vary significantly over the data collection period, lipid readings could not be registered on any occasion. With the exception of skin dryness, skin parameters via both objective and subjective means had significant, positive correlations. Statistically significant correlations emerged between visual assessment of skin wetness at the sacrum (r = -0·441, P < 0·01) and ischia (r = -0·468, P < 0·01) and Norton Risk Assessment Scale scores. It was found that the objective assessment of epidermal hydration (skin wetness) was also significantly associated with PI risk at the sacrum (r = -0·528, P < 0·01), as well as the right ischia (r = -0·410, P < 0·05) and left ischia (r = -0·407, P < 0·05). Erythema, when assessed objectively, was significantly correlated with PI risk at the sacrum (r = -0·322, P < 0·05). Such findings indicating that the finer measures afforded by the SD202 Skin Diagnostic in the assessment of the subtle red hues displayed in erythematous skin may provide an additional advantage over traditional, clinician assessment. © 2015 Medicalhelplines.com Inc and John Wiley & Sons Ltd.

Biases and regularities of grapheme-colour associations in Japanese nonsynaesthetic population.

PubMed

Nagai, Jun-ichi; Yokosawa, Kazuhiko; Asano, Michiko

2016-01-01

Associations between graphemes and colours in a nonsynaesthetic Japanese population were investigated. Participants chose the most suitable colour from 11 basic colour terms for each of 40 graphemes from the four categories of graphemes used in the Japanese language (kana characters, English alphabet letters, and Arabic and kanji numerals). This test was repeated after a three-week interval. In their responses, which were not as temporally consistent as those of grapheme-colour synaesthetes, participants showed biases and regularities that were comparable to those of synaesthetes reported in past studies. Although it has been believed that only synaesthetes, and not nonsynaesthetes, tended to associate graphemes with colours based on grapheme frequency, Berlin and Kay's colour typology, and colour word frequency, participants in this study tended in part to associate graphemes with colours based on the above factors. Moreover, participants that were nonsynaesthetes tended to associate different graphemes that shared sounds and/or meanings (e.g., Arabic and kanji numerals representing the same number) with the same colours, which was analogous to the findings in Japanese synaesthetes. These results support the view that grapheme-colour synaesthesia might have its origins in cross-modal association processes that are shared with the general population.

Discrepancies between descriptions and illustrations of colours in Congo red-stained amyloid, and explanation of discrepant colours.

PubMed

Howie, Alexander J; Owen-Casey, Mared P

2010-09-01

Congo red-stained sections of amyloid may show various colours between crossed polariser and analyser. The aims were to see how papers described the colours, to compare descriptions with illustrations, and to explain the colours. In 160 papers on Congo red-stained amyloid, the commonest descriptions were 'green birefringence' and 'apple-green birefringence'. In 191 figures in 82 papers, 59 (31%) showed a pure green colour, 62 (32%) showed green and yellow or blue and yellow, 38 (20%) showed green and a colour other than yellow, mostly red, and 32 (17%) showed other colours. Discrepancies between colours reported and illustrated were noted in 127 figures (66%). Most (77) were between green alone in descriptions and green and another colour in figures, and 30 were between green in descriptions and no green at all in figures. Pure green can be seen in ideal conditions, but more often there are green and yellow, explained by strain birefringence, and green and red or other combinations, explained by uncrossing of polariser and analyser. These other anomalous colours are just as characteristic of amyloid as the pure green colour. Many papers on Congo red-stained amyloid appear to describe what is expected theoretically rather than what is actually seen.

Leaf Colour as a Signal of Chemical Defence to Insect Herbivores in Wild Cabbage (Brassica oleracea).

PubMed

Green, Jonathan P; Foster, Rosie; Wilkins, Lucas; Osorio, Daniel; Hartley, Susan E

2015-01-01

Leaf colour has been proposed to signal levels of host defence to insect herbivores, but we lack data on herbivory, leaf colour and levels of defence for wild host populations necessary to test this hypothesis. Such a test requires measurements of leaf spectra as they would be sensed by herbivore visual systems, as well as simultaneous measurements of chemical defences and herbivore responses to leaf colour in natural host-herbivore populations. In a large-scale field survey of wild cabbage (Brassica oleracea) populations, we show that variation in leaf colour and brightness, measured according to herbivore spectral sensitivities, predicts both levels of chemical defences (glucosinolates) and abundance of specialist lepidopteran (Pieris rapae) and hemipteran (Brevicoryne brassicae) herbivores. In subsequent experiments, P. rapae larvae achieved faster growth and greater pupal mass when feeding on plants with bluer leaves, which contained lower levels of aliphatic glucosinolates. Glucosinolate-mediated effects on larval performance may thus contribute to the association between P. rapae herbivory and leaf colour observed in the field. However, preference tests found no evidence that adult butterflies selected host plants based on leaf coloration. In the field, B. brassicae abundance varied with leaf brightness but greenhouse experiments were unable to identify any effects of brightness on aphid preference or performance. Our findings suggest that although leaf colour reflects both levels of host defences and herbivore abundance in the field, the ability of herbivores to respond to colour signals may be limited, even in species where performance is correlated with leaf colour.

Leaf Colour as a Signal of Chemical Defence to Insect Herbivores in Wild Cabbage (Brassica oleracea)

PubMed Central

Wilkins, Lucas; Osorio, Daniel; Hartley, Susan E.

2015-01-01

Leaf colour has been proposed to signal levels of host defence to insect herbivores, but we lack data on herbivory, leaf colour and levels of defence for wild host populations necessary to test this hypothesis. Such a test requires measurements of leaf spectra as they would be sensed by herbivore visual systems, as well as simultaneous measurements of chemical defences and herbivore responses to leaf colour in natural host-herbivore populations. In a large-scale field survey of wild cabbage (Brassica oleracea) populations, we show that variation in leaf colour and brightness, measured according to herbivore spectral sensitivities, predicts both levels of chemical defences (glucosinolates) and abundance of specialist lepidopteran (Pieris rapae) and hemipteran (Brevicoryne brassicae) herbivores. In subsequent experiments, P. rapae larvae achieved faster growth and greater pupal mass when feeding on plants with bluer leaves, which contained lower levels of aliphatic glucosinolates. Glucosinolate-mediated effects on larval performance may thus contribute to the association between P. rapae herbivory and leaf colour observed in the field. However, preference tests found no evidence that adult butterflies selected host plants based on leaf coloration. In the field, B. brassicae abundance varied with leaf brightness but greenhouse experiments were unable to identify any effects of brightness on aphid preference or performance. Our findings suggest that although leaf colour reflects both levels of host defences and herbivore abundance in the field, the ability of herbivores to respond to colour signals may be limited, even in species where performance is correlated with leaf colour. PMID:26353086

Colour stainability of indirect CAD-CAM processed composites vs. conventionally laboratory processed composites after immersion in staining solutions.

PubMed

Arocha, Mariana A; Basilio, Juan; Llopis, Jaume; Di Bella, Enrico; Roig, Miguel; Ardu, Stefano; Mayoral, Juan R

2014-07-01

The aim of this study was to determine, by using a spectrophotometer device, the colour stainability of two indirect CAD/CAM processed composites in comparison with two conventionally laboratory-processed composites after being immersed 4 weeks in staining solutions such as coffee, black tea and red wine, using distilled water as control group. Two indirect CAD/CAM composites (Lava Ultimate and Paradigm MZ100) and two conventionally laboratory-processed composites (SR Adoro and Premise Indirect) of shade A2 were selected (160 disc samples). Colour stainability was measured after 4 weeks of immersion in three staining solutions (black tea, coffee, red wine) and distilled water. Specimen's colour was measured each week by means of a spectrophotometer (CIE L*a*b* system). Statistical analysis was carried out performing repeated ANOVA measurements and Tukey's HSD test to evaluate differences in ΔE00 measurements between groups; the interactions among composites, staining solutions and time duration were also evaluated. All materials showed significant discoloration (p<0.01) when compared to control group. The highest ΔE00 observed was with red wine, whereas black tea showed the lowest one. Indirect laboratory-processed resin composites showed the highest colour stability compared with CAD/CAM resin blocks. CAD/CAM processed composites immersed in staining solutions showed lower colour stability when compared to conventionally laboratory-processed resin composites. The demand for CAD/CAM restorations has been increasing; however, colour stainability for such material has been insufficiently studied. Moreover, this has not been performed comparing CAD/CAM processed composites versus laboratory-processed indirect composites by immersing in staining solutions for long immersion periods. Copyright © 2014 Elsevier Ltd. All rights reserved.

A generalized equation for the calculation of receptor noise limited colour distances in n-chromatic visual systems

PubMed Central

Clark, R. C.; Brebner, J. S.

2017-01-01

Researchers must assess similarities and differences in colour from an animal's eye view when investigating hypotheses in ecology, evolution and behaviour. Nervous systems generate colour perceptions by comparing the responses of different spectral classes of photoreceptor through colour opponent mechanisms, and the performance of these mechanisms is limited by photoreceptor noise. Accordingly, the receptor noise limited (RNL) colour distance model of Vorobyev and Osorio (Vorobyev & Osorio 1998 Proc. R. Soc. Lond. B 265, 351–358 (doi:10.1098/rspb.1998.0302)) generates predictions about the discriminability of colours that agree with behavioural data, and consequently it has found wide application in studies of animal colour vision. Vorobyev and Osorio (1998) provide equations to calculate RNL colour distances for animals with di-, tri- and tetrachromatic vision, which is adequate for many species. However, researchers may sometimes wish to compute RNL colour distances for potentially more complex colour visual systems. Thus, we derive a simple, single formula for the computation of RNL distance between two measurements of colour, equivalent to the published di-, tri- and tetrachromatic equations of Vorobyev and Osorio (1998), and valid for colour visual systems with any number of types of noisy photoreceptors. This formula will allow the easy application of this important colour visual model across the fields of ecology, evolution and behaviour. PMID:28989773

The evolution of colour pattern complexity: selection for conspicuousness favours contrasting within-body colour combinations in lizards.

PubMed

Pérez I de Lanuza, G; Font, E

2016-05-01

Many animals display complex colour patterns that comprise several adjacent, often contrasting colour patches. Combining patches of complementary colours increases the overall conspicuousness of the complex pattern, enhancing signal detection. Therefore, selection for conspicuousness may act not only on the design of single colour patches, but also on their combination. Contrasting long- and short-wavelength colour patches are located on the ventral and lateral surfaces of many lacertid lizards. As the combination of long- and short-wavelength-based colours generates local chromatic contrast, we hypothesized that selection may favour the co-occurrence of lateral and ventral contrasting patches, resulting in complex colour patterns that maximize the overall conspicuousness of the signal. To test this hypothesis, we performed a comparative phylogenetic study using a categorical colour classification based on spectral data and descriptive information on lacertid coloration collected from the literature. Our results demonstrate that conspicuous ventral (long-wavelength-based) and lateral (short-wavelength-based) colour patches co-occur throughout the lacertid phylogeny more often than expected by chance, especially in the subfamily Lacertini. These results suggest that selection promotes the evolution of the complex pattern rather than the acquisition of a single conspicuous colour patch, possibly due to the increased conspicuousness caused by the combination of colours with contrasting spectral properties. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

Exaggeration and suppression of iridescence: the evolution of two-dimensional butterfly structural colours

PubMed Central

Wickham, Shelley; Large, Maryanne C.J; Poladian, Leon; Jermiin, Lars S

2005-01-01

Many butterfly species possess ‘structural’ colour, where colour is due to optical microstructures found in the wing scales. A number of such structures have been identified in butterfly scales, including three variations on a simple multi-layer structure. In this study, we optically characterize examples of all three types of multi-layer structure, as found in 10 species. The optical mechanism of the suppression and exaggeration of the angle-dependent optical properties (iridescence) of these structures is described. In addition, we consider the phylogeny of the butterflies, and are thus able to relate the optical properties of the structures to their evolutionary development. By applying two different types of analysis, the mechanism of adaptation is addressed. A simple parsimony analysis, in which all evolutionary changes are given an equal weighting, suggests convergent evolution of one structure. A Dollo parsimony analysis, in which the evolutionary ‘cost’ of losing a structure is less than that of gaining it, implies that ‘latent’ structures can be reused. PMID:16849221

Diamond photonics for distributed quantum networks

NASA Astrophysics Data System (ADS)

Johnson, Sam; Dolan, Philip R.; Smith, Jason M.

2017-09-01

The distributed quantum network, in which nodes comprising small but well-controlled quantum states are entangled via photonic channels, has in recent years emerged as a strategy for delivering a range of quantum technologies including secure communications, enhanced sensing and scalable quantum computing. Colour centres in diamond are amongst the most promising candidates for nodes fabricated in the solid-state, offering potential for large scale production and for chip-scale integrated devices. In this review we consider the progress made and the remaining challenges in developing diamond-based nodes for quantum networks. We focus on the nitrogen-vacancy and silicon-vacancy colour centres, which have demonstrated many of the necessary attributes for these applications. We focus in particular on the use of waveguides and other photonic microstructures for increasing the efficiency with which photons emitted from these colour centres can be coupled into a network, and the use of microcavities for increasing the fraction of photons emitted that are suitable for generating entanglement between nodes.

Initial-state colour dipole emission associated with QCD Pomeron exchange

NASA Astrophysics Data System (ADS)

Bialas, A.; Peschanski, R.

1995-02-01

The initial-state radiation of soft colour dipoles produced together with a single QCD Pomeron exchange (BFKL) in onium-onium scattering is calculated in the framework of Mueller's approach. The resulting dipole production grows with increasing energy and reveals an unexpected feature of a power-law tail at appreciably large transverse distances from the collision axis, this phenomenon being related to the scale-invariant structure of dipole-dipole correlations.

Intermediate BL Lac objects

NASA Astrophysics Data System (ADS)

Bondi, M.; Marchã, M. J. M.; Dallacasa, D.; Stanghellini, C.

2001-08-01

The 200-mJy sample, defined by Marchã et al., contains about 60 nearby, northern, flat-spectrum radio sources. In particular, the sample has proved effective at finding nearby radio-selected BL Lac objects with radio luminosities comparable to those of X-ray-selected objects, and low-luminosity flat-spectrum weak emission-line radio galaxies (WLRGs). The 200-mJy sample contains 23 BL Lac objects (including 6 BL Lac candidates) and 19 WLRGs. We will refer to these subsamples as the 200-mJy BL Lac sample and the 200-mJy WLRG sample, respectively. We have started a systematic analysis of the morphological pc-scale properties of the 200-mJy radio sources using VLBI observations. This paper presents VLBI observations at 5 and 1.6GHz of 14 BL Lac objects and WLRGs selected from the 200-mJy sample. The pc-scale morphology of these objects is briefly discussed. We derive the radio beaming parameters of the 200-mJy BL Lac objects and WLRGs and compare them with those of other BL Lac samples and with a sample of FR I radio galaxies. The overall broad-band radio, optical and X-ray properties of the 200-mJy BL Lac sample are discussed and compared with those of other BL Lac samples, radio- and X-ray-selected. We find that the 200-mJy BL Lac objects fill the gap between HBL and LBL objects in the colour-colour plot, and have intermediate αXOX as expected in the spectral energy distribution unification scenario. Finally, we briefly discuss the role of the WLRGs.

Flesh colour dominates consumer preference for chicken.

PubMed

Kennedy, Orla B; Stewart-Knox, Barbara J; Mitchell, Peter C; Thurnham, David I

2005-04-01

Existing research investigating interactions between visual and oral sensory cues has tended to use model food systems. In contrast, this study compared product quality assessments of corn-fed and wheat-fed chicken products among persons recruited in Northern Ireland. Three approaches have been adopted to investigate the effect of colour upon consumer choice of chicken: sensory assessment under normal lighting; focus group discussion; and sensory assessment under controlled lighting conditions. Initial consumer sensory assessment indicated that wheat-fed chicken was perceived to be tenderer and to have a more intense flavour than that which was corn-fed. Qualitative enquiry discerned that this was because consumers perceived the yellow colour of corn-fed chicken negatively. Yellow-coloured corn-fed chicken was therefore again compared with wheat-fed chicken in terms of flavour, texture and overall liking with the flesh colour disguised by means of controlled lighting. Quality ratings for corn-fed chicken were more positive when the yellow flesh colour was disguised, with corn-fed chicken judged to be tenderer than wheat-fed chicken and more flavoursome. This study illustrates the importance of using a combination of methods to gain insight into interactions between different sensory modalities in consumer quality judgements and adds to previous research on the importance of colour upon consumer choice of real foods.

Spectral heterogeneity on Phobos and Deimos: HiRISE observations and comparisons to Mars Pathfinder results

USGS Publications Warehouse

Thomas, N.; Stelter, R.; Ivanov, A.; Bridges, N.T.; Herkenhoff, K. E.; McEwen, A.S.

2011-01-01

The High-Resolution Imaging Science Experiment (HiRISE) onboard Mars Reconnaissance Orbiter (MRO) has been used to observe Phobos and Deimos at spatial scales of around 6 and 20 m/px, respectively. HiRISE (McEwen et al.; JGR, 112, CiteID E05S02, DOI: 10.1029/2005JE002605, 2007) has provided, for the first time, high-resolution colour images of the surfaces of the Martian moons. When processed, by the production of colour ratio images for example, the data show considerable small-scale heterogeneity, which might be attributable to fresh impacts exposing different materials otherwise largely hidden by a homogenous regolith. The bluer material that is draped over the south-eastern rim of the largest crater on Phobos, Stickney, has been perforated by an impact to reveal redder material and must therefore be relatively thin. A fresh impact with dark crater rays has been identified. Previously identified mass-wasting features in Stickney and Limtoc craters stand out strongly in colour. The interior deposits in Stickney appear more inhomogeneous than previously suspected. Several other local colour variations are also evident. Deimos is more uniform in colour but does show some small-scale inhomogeneity. The bright streamers (Thomas et al.; Icarus, 123, 536556,1996) are relatively blue. One crater to the south-west of Voltaire and its surroundings appear quite strongly reddened with respect to the rest of the surface. The reddening of the surroundings may be the result of ejecta from this impact. The spectral gradients at optical wavelengths observed for both Phobos and Deimos are quantitatively in good agreement with those found by unresolved photometric observations made by the Imager for Mars Pathfinder (IMP; Thomas et al.; JGR, 104, 90559068, 1999). The spectral gradients of the blue and red units on Phobos bracket the results from IMP. ?? 2010 Elsevier Ltd. All rights reserved.

The effects of colour and valence on news evaluation.

PubMed

Kaspar, Kai; Grümmer, Melanie; Kießler, Antje; Neuß, Celina; Schröter, Franziska

2017-12-01

Research across different fields of psychology has reported effects of colour cues on a variety of cognitive processes. Especially, the colour red has been shown to have striking influences. In the context of media reception, however, colour effects have been widely neglected so far. This study made a first step in this direction by investigating the effects of the colour red (compared with blue and grey) on the way news articles are evaluated. Two types of news were framed by a coloured border while the valence of the news content additionally varied. Based on 369 participants who read and evaluated the news articles online, we observed effects for colour cues and news valence in the absence of an interaction effect, indicating that the colour red induced approach motivation. However, only the contrast between red and grey reached statistical significance, indicating that chromatic and achromatic colours may differ in their perceived visual saliency. Overall, these results provide an important complement to previous studies and have practical implications for media researchers and producers. © 2015 International Union of Psychological Science.

Superhump and outburst activity of the cataclysmic variable RZ LMi in the U- and optical passbands

NASA Astrophysics Data System (ADS)

Shugarov, S. Y.; Katysheva, N. A.; Chochol, D.; Krushevska, V. N.; Vozyakova, O. V.

2018-05-01

An analysis of the new U,B,V,RC,IC-photometry of the cataclysmic variable RZ LMi obtained in 2016-17 showed the largest (U-B) colour excess in quiescence as well as during the decline of brightness, associated with the outbursts activity. The smallest (U-B) colour excess was found during the brightness increase from the quiescence. In contrast to the (U-B) colour index, the (B-V),(V-RC),(RC-IC) colour indices exhibits the largest colour excesses near the maximum of the outburst and the smallest during the quiescence. The (B-V) colour index showed also a large excess 1-2 days before a minimum. The detailed study of superhumps during the maximum of activity reveals the largest (U-B) colour excess at the time of the minimum brightness of superhumps. The (B-RC) colour index exhibits a similar behaviour, but with a phase shift of +0.1-{+}0.2 period of superhumps. The tracks in two-colour and colour-magnitude diagrams during superoutbursts are compared with the data for other cataclysmic variables during their outbursts as well as with published theoretical calculations.

Differences between the human eye and the spectrophotometer in the shade matching of tooth colour.

PubMed

Gómez-Polo, Cristina; Gómez-Polo, Miguel; Celemin-Viñuela, Alicia; Martínez Vázquez De Parga, Juan Antonio

2014-06-01

The aim of this work was to assess the agreement between instrumental and visual colour matching. Shade selection with the 3DMaster Toothguide (Vita-Zahnfabrik) was performed for 1361 maxillary central incisors and compared with the shade obtained with the EasyShade Compact (Vita-Zahnfabrik) spectrophotometer. We observed a greater correlation between the objective method and the subjective one in the colour dimension of lightness (Kappa 0.6587), followed by hue (Kappa 0.4337) and finally chroma (Kappa 0.3578). The colour dimension in which the greatest agreement is seen between the operator and the spectrophotometer is value or lightness. This study reveals differences between the measurement of colour via spectrophotometry and the visual shade selection method. According to our results, there is better agreement in the value or lightness colour dimension, which is the most important one in the choice of tooth colour. Copyright © 2014 Elsevier Ltd. All rights reserved.

Gaze Duration Biases for Colours in Combination with Dissonant and Consonant Sounds: A Comparative Eye-Tracking Study with Orangutans.

PubMed

Mühlenbeck, Cordelia; Liebal, Katja; Pritsch, Carla; Jacobsen, Thomas

2015-01-01

Research on colour preferences in humans and non-human primates suggests similar patterns of biases for and avoidance of specific colours, indicating that these colours are connected to a psychological reaction. Similarly, in the acoustic domain, approach reactions to consonant sounds (considered as positive) and avoidance reactions to dissonant sounds (considered as negative) have been found in human adults and children, and it has been demonstrated that non-human primates are able to discriminate between consonant and dissonant sounds. Yet it remains unclear whether the visual and acoustic approach-avoidance patterns remain consistent when both types of stimuli are combined, how they relate to and influence each other, and whether these are similar for humans and other primates. Therefore, to investigate whether gaze duration biases for colours are similar across primates and whether reactions to consonant and dissonant sounds cumulate with reactions to specific colours, we conducted an eye-tracking study in which we compared humans with one species of great apes, the orangutans. We presented four different colours either in isolation or in combination with consonant and dissonant sounds. We hypothesised that the viewing time for specific colours should be influenced by dissonant sounds and that previously existing avoidance behaviours with regard to colours should be intensified, reflecting their association with negative acoustic information. The results showed that the humans had constant gaze durations which were independent of the auditory stimulus, with a clear avoidance of yellow. In contrast, the orangutans did not show any clear gaze duration bias or avoidance of colours, and they were also not influenced by the auditory stimuli. In conclusion, our findings only partially support the previously identified pattern of biases for and avoidance of specific colours in humans and do not confirm such a pattern for orangutans.

Gaze Duration Biases for Colours in Combination with Dissonant and Consonant Sounds: A Comparative Eye-Tracking Study with Orangutans

PubMed Central

Mühlenbeck, Cordelia; Liebal, Katja; Pritsch, Carla; Jacobsen, Thomas

2015-01-01

Research on colour preferences in humans and non-human primates suggests similar patterns of biases for and avoidance of specific colours, indicating that these colours are connected to a psychological reaction. Similarly, in the acoustic domain, approach reactions to consonant sounds (considered as positive) and avoidance reactions to dissonant sounds (considered as negative) have been found in human adults and children, and it has been demonstrated that non-human primates are able to discriminate between consonant and dissonant sounds. Yet it remains unclear whether the visual and acoustic approach–avoidance patterns remain consistent when both types of stimuli are combined, how they relate to and influence each other, and whether these are similar for humans and other primates. Therefore, to investigate whether gaze duration biases for colours are similar across primates and whether reactions to consonant and dissonant sounds cumulate with reactions to specific colours, we conducted an eye-tracking study in which we compared humans with one species of great apes, the orangutans. We presented four different colours either in isolation or in combination with consonant and dissonant sounds. We hypothesised that the viewing time for specific colours should be influenced by dissonant sounds and that previously existing avoidance behaviours with regard to colours should be intensified, reflecting their association with negative acoustic information. The results showed that the humans had constant gaze durations which were independent of the auditory stimulus, with a clear avoidance of yellow. In contrast, the orangutans did not show any clear gaze duration bias or avoidance of colours, and they were also not influenced by the auditory stimuli. In conclusion, our findings only partially support the previously identified pattern of biases for and avoidance of specific colours in humans and do not confirm such a pattern for orangutans. PMID:26466351

Hierarchical photonic structured stimuli-responsive materials as high-performance colorimetric sensors

NASA Astrophysics Data System (ADS)

Lu, Tao; Zhu, Shenmin; Chen, Zhixin; Wang, Wanlin; Zhang, Wang; Zhang, Di

2016-05-01

Hierarchical photonic structures in nature are of special interest because they can be used as templates for fabrication of stimuli-responsive photonic crystals (PCs) with unique structures beyond man-made synthesis. The current stimuli-responsive PCs templated directly from natural PCs showed a very weak external stimuli response and poor durability due to the limitations of natural templates. Herein, we tackle this problem by chemically coating functional polymers, polyacrylamide, on butterfly wing scales which have hierarchical photonic structures. As a result of the combination of the strong water absorption properties of the polyacrylamide and the PC structures of the butterfly wing scales, the designed materials demonstrated excellent humidity responsive properties and a tremendous colour change. The colour change is induced by the refractive index change which is in turn due to the swollen nature of the polymer when the relative humidity changes. The butterfly wing scales also showed an excellent durability which is due to the chemical bonds formed between the polymer and wing scales. The synthesis strategy provides an avenue for the promising applications of stimuli-responsive PCs with hierarchical structures.Hierarchical photonic structures in nature are of special interest because they can be used as templates for fabrication of stimuli-responsive photonic crystals (PCs) with unique structures beyond man-made synthesis. The current stimuli-responsive PCs templated directly from natural PCs showed a very weak external stimuli response and poor durability due to the limitations of natural templates. Herein, we tackle this problem by chemically coating functional polymers, polyacrylamide, on butterfly wing scales which have hierarchical photonic structures. As a result of the combination of the strong water absorption properties of the polyacrylamide and the PC structures of the butterfly wing scales, the designed materials demonstrated excellent humidity responsive properties and a tremendous colour change. The colour change is induced by the refractive index change which is in turn due to the swollen nature of the polymer when the relative humidity changes. The butterfly wing scales also showed an excellent durability which is due to the chemical bonds formed between the polymer and wing scales. The synthesis strategy provides an avenue for the promising applications of stimuli-responsive PCs with hierarchical structures. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr01875k

Using Digitized Handheld Space Shuttle Photography for Terrain Visualization

NASA Technical Reports Server (NTRS)

Eckardt, F. D.; Wilkinson, M. J.; Lulla, K. P.

2000-01-01

Digital terrain models are becoming increasingly available and are readily generated at a whole range of scales. However, the lack of realistic colour and tone in images of terrains remains a problem. Realistic colour and tone are very desirable attributes because they contribute significantly to a powerful visualization of landscapes, both for scientists (Kam's ref) and for the general public. But these attributes are generally still unavailable because few sensors, air- or space-borne, provide true colour, and even fewer do so at a realistic cost. The exception is the growing and accessible archive of US Space Shuttle photography which provides a wealth of potential data suited for more realistic visualization of landscapes.

Perceiving colour at a glimpse: the relevance of where one fixates.

PubMed

Brenner, Eli; Granzier, Jeroen J M; Smeets, Jeroen B J

2007-09-01

We used classification images to examine whether certain parts of a surface are particularly important when judging its colour, such as its centre, its edges, or where one is looking. The scene consisted of a regular pattern of square tiles with random colours from along a short line in colour space. Targets defined by a square array of brighter tiles were presented for 200ms. The colours of the tiles within the target were biased by an amount that led to about 70% of the responses being correct. Subjects fixated a point that fell within the target's lower left quadrant and reported each target's colour. They tended to report the colour of the tiles near the fixation point. The influence of the tiles' colour reversed at the target's border and was weaker outside the target. The colour at the border itself was not particularly important. When coloured tiles were also presented before (and after) target presentation they had an opposite (but weaker) effect, indicating that the change in colour is important. Comparing the influence of tiles outside the target with that of tiles at the position at which the target would soon appear suggests that when judging surface colours during the short "glimpses" between saccades, temporal comparisons can be at least as important as spatial ones. We conclude that eye movements are important for colour vision, both because they determine which part of the surface of interest will be given most weight and because the perceived colour of such a surface also depends on what one looked at last.

Prevalence of Colour Vision Anomalies Amongst Dental Professionals and its Effect on Shade Matching of Teeth.

PubMed

Khosla, Amrit; Maini, Anuj Paul; Wangoo, Anuj; Singh, Sukhman; Mehar, Damanpreet Kaur

2017-01-01

The success of a restoration is dependent on accurate shade matching of teeth leading to studies evaluating the factors affecting the perception of shades. Colour vision anomalies including colour blindness have been found to exist in the population and it has been thought to be a potential factor affecting the colour perception ability. The present study was done to evaluate the prevalence of colour vision anomalies and its effect on matching of shades of teeth. A total of 147 dental professionals were randomly selected for the study and were first tested for visual acuity using the Snellen's Eye Chart so as to carry on the study with only those operators who had a vision of 6/6. Then, the Ishihara's colour charts were used to test the operators for colour vision handicap. In the last stage of the study, test for accuracy of shade selection was done using the Vitapan Classical shade guide. The shade guide tabs were covered to avoid bias. Percentage was used to calculate the prevalence of colour vision handicap and its effect on matching of shades of teeth as compared to normal vision, which was evaluated using Chi square test. Nineteen operators had colour vision anomalies out of hundred operators and only two operators presented with colour blindness. Colour vision anomaly was more prevalent than colour blindness and it was also found that it was more prevalent in males than females. The difference between the accuracy of shade matching between the operators with normal vision and colour vision defect and operators with normal vision and colour blindness was statistically not significant. Colour blindness and colour vision handicap are rare conditions, with the latter being more common in the population. According to our study, it was concluded that no statistically significant difference existed amongst the operators with normal vision and colour vision anomaly or operators with normal vision and colour blindness during the matching of shades of teeth.

Developmental effects of environmental light on male nuptial coloration in Lake Victoria cichlid fish

PubMed Central

Rietveld, Emma; Maan, Martine E.

2018-01-01

Background Efficient communication requires that signals are well transmitted and perceived in a given environment. Natural selection therefore drives the evolution of different signals in different environments. In addition, environmental heterogeneity at small spatial or temporal scales may favour phenotypic plasticity in signaling traits, as plasticity may allow rapid adjustment of signal expression to optimize transmission. In this study, we explore signal plasticity in the nuptial coloration of Lake Victoria cichlids, Pundamilia pundamilia and Pundamilia nyererei. These two species differ in male coloration, which mediates species-assortative mating. They occur in adjacent depth ranges with different light environments. Given the close proximity of their habitats, overlapping at some locations, plasticity in male coloration could contribute to male reproductive success but interfere with reproductive isolation. Methods We reared P. pundamilia, P. nyererei, and their hybrids under light conditions mimicking the two depth ranges in Lake Victoria. From photographs, we quantified the nuptial coloration of males, spanning the entire visible spectrum. In experiment 1, we examined developmental colour plasticity by comparing sibling males reared in each light condition. In experiment 2, we assessed colour plasticity in adulthood, by switching adult males between conditions and tracking coloration for 100 days. Results We found that nuptial colour in Pundamilia did respond plastically to our light manipulations, but only in a limited hue range. Fish that were reared in light conditions mimicking the deeper habitat were significantly greener than those in conditions mimicking shallow waters. The species-specific nuptial colours (blue and red) did not change. When moved to the opposing light condition as adults, males did not change colour. Discussion Our results show that species-specific nuptial colours, which are subject to strong divergent selection by female choice, are not plastic. We do find plasticity in green coloration, a response that may contribute to visual conspicuousness in darker, red-shifted light environments. These results suggest that light-environment-induced plasticity in male nuptial coloration in P. pundamilia and P. nyererei is limited and does not interfere with reproductive isolation. PMID:29312830

The international biological program/human adaptability studies among the Skolt Sami in Finland (1966-1970).

PubMed

Forsius, Henrik; Eriksson, Aldur W; Fellman, Johan

2012-04-16

The population is increasingly lighter pigmented moving in a northward direction in Europe until reaching the Arctic Circle, where the Samis (Lapps) are clearly more pigmented. In 1966-1970, we investigated a total of 689 subjects in the villages of Sevettijärvi and Nellim, including persons with mixed Sami and Finnish heritage; of these, 487 (242 males, 245 females) had both parents classified as Skolt Sami. For estimation of the colour of the iris and hair, international scales were used. For translucency of the iris, pigmentation of the fundus was estimated in 3 different shades. The length and type of eyelashes were classified into 3 categories. To our knowledge, a simultaneous study of the pigmentation of eyebrows, eyelashes and eye fundus at different ages has not previously been published. The age differences of iris colour were highly significant. Iris colour in children varied markedly, and they generally had lighter colours than later in life. Age and sex effects on the translucency of irises were found. Male irises were more translucent. Fundus pigmentation was scanty in the youngest age groups, with full pigmentation being reached at 20 years. Among young individuals hair colour darkens with increasing age. Eyebrow colour was slightly lighter for both sexes in the youngest age groups that in older cohorts. Women had longer eyelashes than males. The main factor of the lighter skin is a higher ability to synthesize vitamin D, providing superior protection against rickets. The Skolt Samis are more pigmented than other Nordic people. In earlier times they had problems with rickets but our studies did not show any essential symptoms of rickets today. Visual acuity among Skolt Samis was good. They had lower prevalence of myopia compared to Finns. The stronger pigmentation of Skolt Samis is probably due to their origin from darker Eastern populations. Since our investigations were made, the Skolt Samis have been to a great part mixed with neighbouring populations and scattered throughout Finland. Even their old language is nowadays used mainly for traditional purposes. Therefore similar studies could not be performed anymore.

The international biological program/human adaptability studies among the Skolt Sami in Finland (1966-1970).

PubMed

Forsius, Henrik; Eriksson, AldurW; Fellman, Johan

2012-01-01

The population is increasingly lighter pigmented moving in a northward direction in Europe until reaching the Arctic Circle, where the Samis (Lapps) are clearly more pigmented. In 1966-1970, we investigated a total of 689 subjects in the villages of Sevettijärvi and Nellim, including persons with mixed Sami and Finnish heritage; of these, 487 (242 males, 245 females) had both parents classified as Skolt Sami. For estimation of the colour of the iris and hair, international scales were used. For translucency of the iris, pigmentation of the fundus was estimated in 3 different shades. The length and type of eyelashes were classified into 3 categories. To our knowledge, a simultaneous study of the pigmentation of eyebrows, eyelashes and eye fundus at different ages has not previously been published. The age differences of iris colour were highly significant. Iris colour in children varied markedly, and they generally had lighter colours than later in life. Age and sex effects on the translucency of irises were found. Male irises were more translucent. Fundus pigmentation was scanty in the youngest age groups, with full pigmentation being reached at 20 years. Among young individuals hair colour darkens with increasing age. Eyebrow colour was slightly lighter for both sexes in the youngest age groups that in older cohorts. Women had longer eyelashes than males. The main factor of the lighter skin is a higher ability to synthesize vitamin D, providing superior protection against rickets. The Skolt Samis are more pigmented than other Nordic people. In earlier times they had problems with rickets but our studies did not show any essential symptoms of rickets today. Visual acuity among Skolt Samis was good. They had lower prevalence of myopia compared to Finns. The stronger pigmentation of Skolt Samis is probably due to their origin from darker Eastern populations. Since our investigations were made, the Skolt Samis have been to a great part mixed with neighbouring populations and scattered throughout Finland. Even their old language is nowadays used mainly for traditional purposes. Therefore similar studies could not be performed anymore.

Turbo Pascal/GEM Software Interface for Scientific Graph Preparation

DTIC Science & Technology

1991-04-01

Well as whatever artistic touches that the author may desire. Even colour hardcopy reproduuction is possible through use of an appropriate colour...drawing axes on graphs. The unit also contains an autoscaling procedure that may be applied separately to all curve axes. 6.3.1 Available structures...procedures AxisScale Provides autoscaled values from specified min and max values. LabelRightAxis Draws ticks and numbers on the right axis. LabelXAxis

The importance of chill rate when characterising colour change of lamb meat during retail display.

PubMed

Jacob, R H; Thomson, K L

2012-02-01

An experiment was conducted to compare the effect of two chilling rates (Con and Fast) on colour change of lamb meat during simulated retail display. Measurements were made on 3 muscles; LD (m. longisimuss dorsi), SM (m semimembranosus) and ST (m. semitendinous). Meat samples from 32 Merino crossbred lambs were vacuum packed and stored for 5 days at 2 °C, then cut and overwrapped in polyvinyl chloride film on black polystyrene trays, stored in a display cabinet at 4 °C with lights on and measured twice daily for 4 days, using a Hunterlab minilab 45/20L D65, aperture 10°. Sarcomere length was shorter, shear force higher and colour change greater in meat from the Fast treatment compared to the Con treatment. Colour differences between treatments were likely due to oxygenation (bloom) as well as oxidation effects. Chill rate is important when characterising colour change during display and should be considered in measurement protocols. Copyright © 2011 Elsevier Ltd. All rights reserved.

Site, gender and age variation in normal skin colour on the back and the forearm: tristimulus colorimeter measurements.

PubMed

Fullerton, A; Serup, J

1997-02-01

To study whether anatomical location and age and gender of subjects had any influence on the objective skin colour measurements. Baseline colour in prone position was measured with the Minolta ChromaMeter® in the upper, middle and lower level of the upper back and on the forearm of 168 volunteers. These two sites are commonly used in skin testing. Higher basal a* and lower basal L* levels were found on the upper scapular region compared to the lower scapular region and the subscapular region. The basal b* level showed no variation relative to site. The basal a* and the basal b* levels were lower on the forearm compared to the upper back while the basal L* level was higher. Females above 65 years showed a less coloured skin with lower values as compared to those of younger age. Females were found to have a generally lower basal a* level than males both on the upper back and forearm skin. These relatively major differences and sources of variation have to be considered when planning irritancy studies where colour differences between erythema and normal skin is used.

Colour spaces in ecology and evolutionary biology.

PubMed

Renoult, Julien P; Kelber, Almut; Schaefer, H Martin

2017-02-01

The recognition that animals sense the world in a different way than we do has unlocked important lines of research in ecology and evolutionary biology. In practice, the subjective study of natural stimuli has been permitted by perceptual spaces, which are graphical models of how stimuli are perceived by a given animal. Because colour vision is arguably the best-known sensory modality in most animals, a diversity of colour spaces are now available to visual ecologists, ranging from generalist and basic models allowing rough but robust predictions on colour perception, to species-specific, more complex models giving accurate but context-dependent predictions. Selecting among these models is most often influenced by historical contingencies that have associated models to specific questions and organisms; however, these associations are not always optimal. The aim of this review is to provide visual ecologists with a critical perspective on how models of colour space are built, how well they perform and where their main limitations are with regard to their most frequent uses in ecology and evolutionary biology. We propose a classification of models based on their complexity, defined as whether and how they model the mechanisms of chromatic adaptation and receptor opponency, the nonlinear association between the stimulus and its perception, and whether or not models have been fitted to experimental data. Then, we review the effect of modelling these mechanisms on predictions of colour detection and discrimination, colour conspicuousness, colour diversity and diversification, and for comparing the perception of colour traits between distinct perceivers. While a few rules emerge (e.g. opponent log-linear models should be preferred when analysing very distinct colours), in general model parameters still have poorly known effects. Colour spaces have nonetheless permitted significant advances in ecology and evolutionary biology, and more progress is expected if ecologists compare results between models and perform behavioural experiments more routinely. Such an approach would further contribute to a better understanding of colour vision and its links to the behavioural ecology of animals. While visual ecology is essentially a transfer of knowledge from visual sciences to evolutionary ecology, we hope that the discipline will benefit both fields more evenly in the future. © 2015 Cambridge Philosophical Society.

A new genus and species of xenodermatid snake (Squamata: Caenophidia: Xenodermatidae) from northern Lao People's Democratic Republic.

PubMed

Teynié, Alexandre; David, Patrick; Lottier, Anne; Le, Minh Duc; Vidal, Nicolas; Nguyen, Truong Quang

2015-03-09

A male snake collected in Louangphabang Province and a second specimen observed in Houaphan Province, North Laos, share morphological characters with the Asian genus Fimbrios Smith, 1921, including erected edges on the first supra- and infralabial scales, but differ in the following morphological characters: fewer dorsal scale rows (25-27 vs. 30-33), fewer maxillary teeth (27 vs. 30-35), posterior teeth progressively slightly enlarged, and especially the correspondence of two dorsal scale rows per ventral plate throughout the body (i.e. the first dorsal scale row made of a small scale above the fore part of a ventral, followed by a much larger scale above its hind part), a condition known only in Xenodermus Reinhardt, 1836. As the Laotian specimens differ in morphological characters from other genera and species in the family Xenodermatidae, and on the basis of molecular analyses showing a large genetic divergence from the genus Fimbrios (p-distance ≥14.7 %, mitochondrial COI gene), we place these specimens in a new genus, Parafimbrios gen. nov., and describe them as a new species, Parafimbrios lao sp. nov. Besides the characters mentioned above, the new species is diagnosed by a combination of the following ones: small, strongly keeled dorsal scales; rostral and first four supra- and infralabials with raised, erected edges; horizontal tissue ridges above the rostral; loreal single, large, elongate; ventral scales 177-189; subcaudals 55-56, undivided; dorsal colour purplish-grey, neck with a broad, very pale grey collar reaching downwards the pale grey colour of the venter. The morphological characters of the new genus are compared with those of the genera Fimbrios Smith, 1921, Xenodermus Reinhardt, 1836, Stoliczkaia Jerdon, 1870, Achalinus Peters, 1869, and Xylophis Beddome, 1878. A key to the genera Achalinus, Fimbrios and Parafimbrios gen. nov. is provided. Parafimbrios laos spec. nov. is the 111th snake species currently recorded from Laos.

Industrial-scale spray layer-by-layer assembly for production of biomimetic photonic systems.

PubMed

Krogman, K C; Cohen, R E; Hammond, P T; Rubner, M F; Wang, B N

2013-12-01

Layer-by-layer assembly is a powerful and flexible thin film process that has successfully reproduced biomimetic photonic systems such as structural colour. While most of the seminal work has been carried out using slow and ultimately unscalable immersion assembly, recent developments using spray layer-by-layer assembly provide a platform for addressing challenges to scale-up and manufacturability. A series of manufacturing systems has been developed to increase production throughput by orders of magnitude, making commercialized structural colour possible. Inspired by biomimetic photonic structures we developed and demonstrated a heat management system that relies on constructive reflection of near infrared radiation to bring about dramatic reductions in heat content.

A new species of cat snake (Reptilia: Serpentes: Colubridae: Boiga) from dry forests of eastern Peninsular India.

PubMed

Vogel, Gernot; Ganesh, S R

2013-01-01

A new species of cat snake, related to Boiga beddomei (Wall, 1909), is described from the dry forests of eastern Peninsular India. It occupies a large geographic range from Berhampore (type locality), near the River Mahanadi in the northeast to Kaigal near the southern Eastern Ghats in the southwest. The new species is diagnosed by having the following combination of characters: 19 dorsal scale rows at midbody, a high number of ventral scales for the genus Boiga (248-259), a yellowish-green dorsal colouration with numerous faint black bands, an uniform, unpatterned yellow-coloured venter and a relatively short tail (0.180-0.200 of the total length).

Colour change in cyanosis and the confusions of congenital colour vision deficient observers.

PubMed

McNamara, Renae; Taylor, Clair M; McKenzie, David K; Coroneo, Minas T; Dain, Stephen J

2010-09-01

Visual recognition of cyanosis is an important clinical activity. While pulse oximetry is almost universal in the hospital environment, there are circumstances where it is not available or may be unreliable. Cyanosis recognition is affected by lighting colour. In addition, there is, mainly anecdotal, evidence that people with greater colour vision deficiencies (CVDs) have particular difficulty and there is no effective lighting strategy to assist in the observation. The change of blood colour with oxygenation has been shown to lie close to the direction of colour confusions made by congenital red-green dichromats. The important sites of observation are lips, nail beds and palm creases. 10 subjects who were known to be chronically hypoxaemic were recruited from the chronic respiratory program. Their blood oxygen saturation (SpO(2)) varied from 84% to 96% pre-exercise, and 61-84% post-exercise. Ten normal subjects were recruited whose SpO(2) was 99% or 100%. The spectral radiances of lips, nail beds and palm creases were measured using a telespectroradiometer and compared with the spectral radiances of a white tile of known spectral reflectances measured in the same location. This is a non-contact method of measurement, avoiding the blanching caused by pressure of contact methods. The spectral reflectances were calculated, and the chromaticities calculated for a Planckian radiator T = 4000K. Measurements on lips yielded the most consistent results. The colour changes pre- and post-exercise and compared with normal colour lie generally along a deutan confusion line. These results show the direction of the colour change and confirm the, previously anecdotal, difficulties in detecting cyanosis by observers with CVDs. © 2010 The Authors, Ophthalmic and Physiological Optics © 2010 The College of Optometrists.

Rainbow peacock spiders inspire miniature super-iridescent optics.

PubMed

Hsiung, Bor-Kai; Siddique, Radwanul Hasan; Stavenga, Doekele G; Otto, Jürgen C; Allen, Michael C; Liu, Ying; Lu, Yong-Feng; Deheyn, Dimitri D; Shawkey, Matthew D; Blackledge, Todd A

2017-12-22

Colour produced by wavelength-dependent light scattering is a key component of visual communication in nature and acts particularly strongly in visual signalling by structurally-coloured animals during courtship. Two miniature peacock spiders (Maratus robinsoni and M. chrysomelas) court females using tiny structured scales (~ 40 × 10 μm 2 ) that reflect the full visual spectrum. Using TEM and optical modelling, we show that the spiders' scales have 2D nanogratings on microscale 3D convex surfaces with at least twice the resolving power of a conventional 2D diffraction grating of the same period. Whereas the long optical path lengths required for light-dispersive components to resolve individual wavelengths constrain current spectrometers to bulky sizes, our nano-3D printed prototypes demonstrate that the design principle of the peacock spiders' scales could inspire novel, miniature light-dispersive components.

Multivariate methods to visualise colour-space and colour discrimination data.

PubMed

Hastings, Gareth D; Rubin, Alan

2015-01-01

Despite most modern colour spaces treating colour as three-dimensional (3-D), colour data is usually not visualised in 3-D (and two-dimensional (2-D) projection-plane segments and multiple 2-D perspective views are used instead). The objectives of this article are firstly, to introduce a truly 3-D percept of colour space using stereo-pairs, secondly to view colour discrimination data using that platform, and thirdly to apply formal statistics and multivariate methods to analyse the data in 3-D. This is the first demonstration of the software that generated stereo-pairs of RGB colour space, as well as of a new computerised procedure that investigated colour discrimination by measuring colour just noticeable differences (JND). An initial pilot study and thorough investigation of instrument repeatability were performed. Thereafter, to demonstrate the capabilities of the software, five colour-normal and one colour-deficient subject were examined using the JND procedure and multivariate methods of data analysis. Scatter plots of responses were meaningfully examined in 3-D and were useful in evaluating multivariate normality as well as identifying outliers. The extent and direction of the difference between each JND response and the stimulus colour point was calculated and appreciated in 3-D. Ellipsoidal surfaces of constant probability density (distribution ellipsoids) were fitted to response data; the volumes of these ellipsoids appeared useful in differentiating the colour-deficient subject from the colour-normals. Hypothesis tests of variances and covariances showed many statistically significant differences between the results of the colour-deficient subject and those of the colour-normals, while far fewer differences were found when comparing within colour-normals. The 3-D visualisation of colour data using stereo-pairs, as well as the statistics and multivariate methods of analysis employed, were found to be unique and useful tools in the representation and study of colour. Many additional studies using these methods along with the JND and other procedures have been identified and will be reported in future publications. © 2014 The Authors Ophthalmic & Physiological Optics © 2014 The College of Optometrists.

Production of an anthocyanin-rich food colourant from Thymus moroderi and its application in foods.

PubMed

Díaz-García, Miriam Cristina; Castellar, María Rosario; Obón, José María; Obón, Concepción; Alcaraz, Francisco; Rivera, Diego

2015-04-01

Anthocyanins and other polyphenols from flowers and bracts of Thymus sp. are studied. An anthocyanin-rich food colourant with interesting high antioxidant activity from Thymus moroderi has been obtained, and applied to colour foods. Anthocyanins and other polyphenols from T. moroderi and another five Thymus sp. were extracted in methanol/hydrochloric acid 0.1 mol L(-1) (50/50, v/v) 2 h stirring at 50 °C. They were identified and quantified by HPLC-PDA-MS and UHPLC-PDA-fluorescence, as total individual polyphenols. Total polyphenols were also determined. Flowers had higher anthocyanins and other polyphenols concentrations than bracts; for example, total polyphenols content of T. moroderi were 131.58 and 61.98 g GAE kg(-1) vegetal tissue, respectively. A liquid concentrated colourant was obtained from T. moroderi using water/citric acid as solvent. It was characterised and compared with other two commercial anthocyanin-rich food colourants from red grape skin and red carrot (colour strength of 1.7 and 3.6 AU, respectively). T. moroderi colourant had 1.2 AU colour strength, and high storage stability (>97.1% remaining colour after 110 days at 4 °C). It showed a higher polyphenols content than commercial colourants. Its antioxidant activity was 0.707 mmol Trolox eq. g(-1) plant dry weight, 69.5 times higher than red carrot. The three colourants were applied to colour yogurts, giving pinky tonalities. The colour did not change evidently (ΔE*(ab)  < 3) when stored under refrigeration during 1 month. T. moroderi can be a source of anthocyanin-rich food colourant (E-163) with both high polyphenols content and high antioxidant activity. This colourant gives a stable colour to a yogurt during 1 month. These results expand the use of natural colourants. © 2014 Society of Chemical Industry.

Comparative psychophysics of bumblebee and honeybee colour discrimination and object detection.

PubMed

Dyer, Adrian G; Spaethe, Johannes; Prack, Sabina

2008-07-01

Bumblebee (Bombus terrestris) discrimination of targets with broadband reflectance spectra was tested using simultaneous viewing conditions, enabling an accurate determination of the perceptual limit of colour discrimination excluding confounds from memory coding (experiment 1). The level of colour discrimination in bumblebees, and honeybees (Apis mellifera) (based upon previous observations), exceeds predictions of models considering receptor noise in the honeybee. Bumblebee and honeybee photoreceptors are similar in spectral shape and spacing, but bumblebees exhibit significantly poorer colour discrimination in behavioural tests, suggesting possible differences in spatial or temporal signal processing. Detection of stimuli in a Y-maze was evaluated for bumblebees (experiment 2) and honeybees (experiment 3). Honeybees detected stimuli containing both green-receptor-contrast and colour contrast at a visual angle of approximately 5 degrees , whilst stimuli that contained only colour contrast were only detected at a visual angle of 15 degrees . Bumblebees were able to detect these stimuli at a visual angle of 2.3 degrees and 2.7 degrees , respectively. A comparison of the experiments suggests a tradeoff between colour discrimination and colour detection in these two species, limited by the need to pool colour signals to overcome receptor noise. We discuss the colour processing differences and possible adaptations to specific ecological habitats.

Behavioural evidence for colour vision in an elasmobranch.

PubMed

Van-Eyk, Sarah M; Siebeck, Ulrike E; Champ, Connor M; Marshall, Justin; Hart, Nathan S

2011-12-15

Little is known about the sensory abilities of elasmobranchs (sharks, skates and rays) compared with other fishes. Despite their role as apex predators in most marine and some freshwater habitats, interspecific variations in visual function are especially poorly studied. Of particular interest is whether they possess colour vision and, if so, the role(s) that colour may play in elasmobranch visual ecology. The recent discovery of three spectrally distinct cone types in three different species of ray suggests that at least some elasmobranchs have the potential for functional trichromatic colour vision. However, in order to confirm that these species possess colour vision, behavioural experiments are required. Here, we present evidence for the presence of colour vision in the giant shovelnose ray (Glaucostegus typus) through the use of a series of behavioural experiments based on visual discrimination tasks. Our results show that these rays are capable of discriminating coloured reward stimuli from other coloured (unrewarded) distracter stimuli of variable brightness with a success rate significantly different from chance. This study represents the first behavioural evidence for colour vision in any elasmobranch, using a paradigm that incorporates extensive controls for relative stimulus brightness. The ability to discriminate colours may have a strong selective advantage for animals living in an aquatic ecosystem, such as rays, as a means of filtering out surface-wave-induced flicker.

Evolution of iris colour in relation to cavity nesting and parental care in passerine birds.

PubMed

Davidson, Gabrielle L; Thornton, Alex; Clayton, Nicola S

2017-01-01

Strong selection pressures are known to act on animal coloration. Although many animals vary in eye colour, virtually no research has investigated the functional significance of these colour traits. Passeriformes have a range of iris colours, making them an ideal system to investigate how and why iris colour has evolved. Using phylogenetic comparative methods, we tested the hypothesis that conspicuous iris colour in passerine birds evolved in response to (a) coordination of offspring care and (b) cavity nesting, two traits thought to be involved in intra-specific gaze sensitivity. We found that iris colour and cooperative offspring care by two or more individuals evolved independently, suggesting that bright eyes are not important for coordinating parental care through eye gaze. Furthermore, we found that evolution between iris colour and nesting behaviour did occur in a dependent manner, but contrary to predictions, transitions to coloured eyes were not more frequent in cavity nesters than non-cavity nesters. Instead, our results indicate that selection away from having bright eyes was much stronger in non-cavity nesters than cavity nesters, perhaps because conspicuous eye coloration in species not concealed within a cavity would be more visible to predators. © 2017 The Authors.

Evolution of iris colour in relation to cavity nesting and parental care in passerine birds

PubMed Central

Thornton, Alex

2017-01-01

Strong selection pressures are known to act on animal coloration. Although many animals vary in eye colour, virtually no research has investigated the functional significance of these colour traits. Passeriformes have a range of iris colours, making them an ideal system to investigate how and why iris colour has evolved. Using phylogenetic comparative methods, we tested the hypothesis that conspicuous iris colour in passerine birds evolved in response to (a) coordination of offspring care and (b) cavity nesting, two traits thought to be involved in intra-specific gaze sensitivity. We found that iris colour and cooperative offspring care by two or more individuals evolved independently, suggesting that bright eyes are not important for coordinating parental care through eye gaze. Furthermore, we found that evolution between iris colour and nesting behaviour did occur in a dependent manner, but contrary to predictions, transitions to coloured eyes were not more frequent in cavity nesters than non-cavity nesters. Instead, our results indicate that selection away from having bright eyes was much stronger in non-cavity nesters than cavity nesters, perhaps because conspicuous eye coloration in species not concealed within a cavity would be more visible to predators. PMID:28077686

Conspicuous plumage colours are highly variable

PubMed Central

Szecsenyi, Beatrice; Nakagawa, Shinichi; Peters, Anne

2017-01-01

Elaborate ornamental traits are often under directional selection for greater elaboration, which in theory should deplete underlying genetic variation. Despite this, many ornamental traits appear to remain highly variable and how this essential variation is maintained is a key question in evolutionary biology. One way to address this question is to compare differences in intraspecific variability across different types of traits to determine whether high levels of variation are associated with specific trait characteristics. Here we assess intraspecific variation in more than 100 plumage colours across 55 bird species to test whether colour variability is linked to their level of elaboration (indicated by degree of sexual dichromatism and conspicuousness) or their condition dependence (indicated by mechanism of colour production). Conspicuous colours had the highest levels of variation and conspicuousness was the strongest predictor of variability, with high explanatory power. After accounting for this, there were no significant effects of sexual dichromatism or mechanisms of colour production. Conspicuous colours may entail higher production costs or may be more sensitive to disruptions during production. Alternatively, high variability could also be related to increased perceptual difficulties inherent to discriminating highly elaborate colours. Such psychophysical effects may constrain the exaggeration of animal colours. PMID:28100823

Conspicuous plumage colours are highly variable.

PubMed

Delhey, Kaspar; Szecsenyi, Beatrice; Nakagawa, Shinichi; Peters, Anne

2017-01-25

Elaborate ornamental traits are often under directional selection for greater elaboration, which in theory should deplete underlying genetic variation. Despite this, many ornamental traits appear to remain highly variable and how this essential variation is maintained is a key question in evolutionary biology. One way to address this question is to compare differences in intraspecific variability across different types of traits to determine whether high levels of variation are associated with specific trait characteristics. Here we assess intraspecific variation in more than 100 plumage colours across 55 bird species to test whether colour variability is linked to their level of elaboration (indicated by degree of sexual dichromatism and conspicuousness) or their condition dependence (indicated by mechanism of colour production). Conspicuous colours had the highest levels of variation and conspicuousness was the strongest predictor of variability, with high explanatory power. After accounting for this, there were no significant effects of sexual dichromatism or mechanisms of colour production. Conspicuous colours may entail higher production costs or may be more sensitive to disruptions during production. Alternatively, high variability could also be related to increased perceptual difficulties inherent to discriminating highly elaborate colours. Such psychophysical effects may constrain the exaggeration of animal colours. © 2017 The Author(s).

Fundus autofluorescence and colour fundus imaging compared during telemedicine screening in patients with diabetes.

PubMed

Kolomeyer, Anton M; Baumrind, Benjamin R; Szirth, Bernard C; Shahid, Khadija; Khouri, Albert S

2013-06-01

We investigated the use of fundus autofluorescence (FAF) imaging in screening the eyes of patients with diabetes. Images were obtained from 50 patients with type 2 diabetes undergoing telemedicine screening with colour fundus imaging. The colour and FAF images were obtained with a 15.1 megapixel non-mydriatic retinal camera. Colour and FAF images were compared for pathology seen in nonproliferative and proliferative diabetic retinopathy (NPDR and PDR, respectively). A qualitative assessment was made of the ease of detecting early retinopathy changes and the extent of existing retinopathy. The mean age of the patients was 47 years, most were male (82%) and most were African American (68%). Their mean visual acuity was 20/45 and their mean intraocular pressure was 14.3 mm Hg. Thirty-eight eyes (76%) did not show any diabetic retinopathy changes on colour or FAF imaging. Seven patients (14%) met the criteria for NPDR and five (10%) for severe NPDR or PDR. The most common findings were microaneurysms, hard exudates and intra-retinal haemorrhages (IRH) (n = 6 for each). IRH, microaneurysms and chorioretinal scars were more easily visible on FAF images. Hard exudates, pre-retinal haemorrhage and fibrosis, macular oedema and Hollenhorst plaque were easier to identify on colour photographs. The value of FAF imaging as a complementary technique to colour fundus imaging in detecting diabetic retinopathy during ocular screening warrants further investigation.

Self-reported skin colour and erythemal sensitivity vs. objectively measured constitutive skin colour in an African population with predominantly dark skin.

PubMed

Wright, Caradee Y; Wilkes, Marcus; du Plessis, Johan L; Reeder, Anthony I

2015-11-01

Skin colour is an important factor in skin-related diseases. Accurate determination of skin colour is important for disease prevention and supporting healthy sun behaviour, yet such data are lacking for dark skin types. Self-perceived, natural skin colour and sun-skin reaction were compared with objectively measured skin colour among an African population with predominantly dark skin. Unexposed skin of 556 adults (70.1% Black) was measured with a reflectance spectrophotometer to calculate an individual typology angle (°ITA). Participants reported self-perceived skin colour and erythemal sensitivity. There was a strong, positive monotonic correlation between self-reported and measured skin colour (Spearman ρ = 0.6438, P < 0.001), but only a weak correlation between self-reported erythemal sensitivity and measured skin colour (Spearman ρ = 0.2713, P < 0.001). Self-report biases in underestimation and overestimation of skin colour were evident. Many participants with 'dark brown' and 'black' skin had difficulty in classifying erythemal sensitivity. In Africa, self-reported skin colour could potentially be used in lieu of spectrophotometer measurements, but options for questions on sunburn and tanning require suitable adjustment. Our study provides evidence of range in °ITA values among residents in Africa and reinforces previous results that self-report may be reliable for determining skin colour, but not erythemal sensitivity, for dark skin individuals. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Colour Preference to Emotions in Relation to the Anxiety Level among School Children in Puducherry – A Cross-Sectional Study

PubMed Central

Prathima, Gajula Shivashankarappa; Sajeev, Renganathan; Kayalvizhi, Gurusamy; Ramesh, Venkatesan; Ezhumalai, Govindasamy

2016-01-01

Introduction Dental setting plays an important role in child’s behavior and cooperation to the planned dental treatment. Adding attractive colours to the dental environment and by incorporating colourful equipments can make the child feel good and be at ease. This study tries to convey the relationship between colours and dental anxiety among children. Aim To evaluate the colour preference to emotions in relation to children’s age, gender and anxiety level. Materials and Methods A total of 382 children aged 6-12 years were randomly selected from schools in and around Puducherry. Modified dental anxiety scale was recorded by a calibrated examiner. Each question was scored from one (not anxious) to five (extremely anxious); such that the total score ranges from 5 to 25, wherein a score of 15 or more was considered to be anxious. Based on this, children were divided into anxious and non-anxious groups. All the children were provided with eight different coloured crayon pencils and were asked to shade two cartoon emoticons indicating happiness and sadness with their preferred colour. Values were tabulated and statistically analyzed to evaluate the association between the variables using Z test, Chi-square, Chi-square goodness of fit and odds ratio. (p≤0.05 was considered statistically significant). Results Among 382 children, 77% (294) were graded as anxious and 23% (88) as non- anxious. For positive emotion (happiness), 31.2% (119) children preferred blue followed by pink 29.3% (112). For negative emotion (sadness), 52.1% (199) of children preferred black and 46.9% (179) preferred red. Association between colour and emotion was highly significant (p= 0.005). Conclusion From the colours preferred by the children in our study, it can be concluded that colours like blue and pink in the dental set-up could enhance a positive attitude while black and red could develop a negative outlook in their mind. PMID:27630948

Colour Preference to Emotions in Relation to the Anxiety Level among School Children in Puducherry - A Cross-Sectional Study.

PubMed

Annamary, Kattakayam; Prathima, Gajula Shivashankarappa; Sajeev, Renganathan; Kayalvizhi, Gurusamy; Ramesh, Venkatesan; Ezhumalai, Govindasamy

2016-07-01

Dental setting plays an important role in child's behavior and cooperation to the planned dental treatment. Adding attractive colours to the dental environment and by incorporating colourful equipments can make the child feel good and be at ease. This study tries to convey the relationship between colours and dental anxiety among children. To evaluate the colour preference to emotions in relation to children's age, gender and anxiety level. A total of 382 children aged 6-12 years were randomly selected from schools in and around Puducherry. Modified dental anxiety scale was recorded by a calibrated examiner. Each question was scored from one (not anxious) to five (extremely anxious); such that the total score ranges from 5 to 25, wherein a score of 15 or more was considered to be anxious. Based on this, children were divided into anxious and non-anxious groups. All the children were provided with eight different coloured crayon pencils and were asked to shade two cartoon emoticons indicating happiness and sadness with their preferred colour. Values were tabulated and statistically analyzed to evaluate the association between the variables using Z test, Chi-square, Chi-square goodness of fit and odds ratio. (p≤0.05 was considered statistically significant). Among 382 children, 77% (294) were graded as anxious and 23% (88) as non- anxious. For positive emotion (happiness), 31.2% (119) children preferred blue followed by pink 29.3% (112). For negative emotion (sadness), 52.1% (199) of children preferred black and 46.9% (179) preferred red. Association between colour and emotion was highly significant (p= 0.005). From the colours preferred by the children in our study, it can be concluded that colours like blue and pink in the dental set-up could enhance a positive attitude while black and red could develop a negative outlook in their mind.

Some aspects of colour perception among patients with Alzheimer's disease.

PubMed

Wijk, H; Sivik, L

1995-01-01

The proportion of elderly people in western societies is on the increase. At the same time, demands are being heard for improvements in the quality of health care, including the design of the physical environment. The aim of this study was to call attention to some aspects of colour and the possibilities of using it as an orientational aid for institutionalized demented patients and thereby enhance the quality of their care. A pilot study was carried out to establish whether patients with Alzheimer's disease are different from non-demented patients regarding certain aspects of colour perception. Twelve hospitalized patients with Alzheimer's disease were compared with a matched control group of non-demented patients regarding colour naming, colour discrimination and colour preference. No significant differences were found between the groups. In an additional experiment to test short-term memory it was found that the patients with Alzheimer's disease gained substantial help from colour cues. It is concluded that colour should be taken into account in the designing of the health care environment, particularly geriatric wards.

Grapheme-colour synaesthesia yields an ordinary rather than extraordinary memory advantage: evidence from a group study.

PubMed

Rothen, Nicolas; Meier, Beat

2010-04-01

In synaesthesia, the input of one sensory modality automatically triggers an additional experience, not normally triggered by the input of that modality. Therefore, compared to non-synaesthetes, additional experiences exist and these may be used as retrieval cues when memory is tested. Previous case studies have suggested that synaesthesia may yield even extraordinary memory abilities. However, group studies found either a task-specific memory advantage or no performance advantage at all. The aim of the present study was to test whether grapheme-colour synaesthesia gives rise to a general memory benefit using a standardised memory test (Wechsler Memory Scale). The synaesthetes showed a performance advantage in episodic memory tests, but not in short-term memory tests. However, performance was still within the ordinary range. The results support the hypothesis that synaesthesia provides for a richer world of experience and as a consequence additional retrieval cues may be available and beneficial but not to the point of extraordinary memory ability.

How big does a coloured overlay have to be?

PubMed

Waldie, Michelle; Wilkins, Arnold

2004-01-01

Coloured overlays and coloured lenses can both increase reading speed, but when they do their colour is not necessarily the same, suggesting that the beneficial effects of a coloured filter might depend upon the area of the visual field that it colours. We investigated the effects of overlays on reading speed and varied the size of the overlay and the colour of the surround. Children who had been assessed with coloured overlays were required to read a passage of randomly ordered common words. The words were printed in black ink as a block of text positioned centrally on an A4 page of white paper in landscape orientation. The speed of reading was compared under four conditions: (1) without an overlay; (2) with an overlay of the chosen colour covering the entire page; (3) with the overlay cut so that it just covered the text but left the margin white; (4) with the overlay of the chosen colour covering the text but with the margin coloured a complementary colour, using a second overlay. The children who were using an overlay read more quickly with the overlay; those who were no longer using the overlay did not. Although the block of text covered less than half the page, the colour and nature of the margin did not affect reading speed significantly. These findings suggest that in order to be effective at improving reading speed an overlay needs to cover the text, but not necessarily the remainder of the page, which means that smaller overlays may sometimes be sufficient.

Seasonal Changes in Colour: A Comparison of Structural, Melanin- and Carotenoid-Based Plumage Colours

PubMed Central

Delhey, Kaspar; Burger, Claudia; Fiedler, Wolfgang; Peters, Anne

2010-01-01

Background Plumage coloration is important for bird communication, most notably in sexual signalling. Colour is often considered a good quality indicator, and the expression of exaggerated colours may depend on individual condition during moult. After moult, plumage coloration has been deemed fixed due to the fact that feathers are dead structures. Still, many plumage colours change after moult, although whether this affects signalling has not been sufficiently assessed. Methodology/Principal Findings We studied changes in coloration after moult in four passerine birds (robin, Erithacus rubecula; blackbird, Turdus merula; blue tit, Cyanistes caeruleus; and great tit, Parus major) displaying various coloration types (melanin-, carotenoid-based and structural). Birds were caught regularly during three years to measure plumage reflectance. We used models of avian colour vision to derive two variables, one describing chromatic and the other achromatic variation over the year that can be compared in magnitude among different colour types. All studied plumage patches but one (yellow breast of the blue tit) showed significant chromatic changes over the year, although these were smaller than for a typical dynamic trait (bill colour). Overall, structural colours showed a reduction in relative reflectance at shorter wavelengths, carotenoid-based colours the opposite pattern, while no general pattern was found for melanin-based colours. Achromatic changes were also common, but there were no consistent patterns of change for the different types of colours. Conclusions/Significance Changes of plumage coloration independent of moult are probably widespread; they should be perceivable by birds and have the potential to affect colour signalling. PMID:20644723

Further evidence for population specific differences in the effect of DNA markers and gender on eye colour prediction in forensics.

PubMed

Pośpiech, Ewelina; Karłowska-Pik, Joanna; Ziemkiewicz, Bartosz; Kukla, Magdalena; Skowron, Małgorzata; Wojas-Pelc, Anna; Branicki, Wojciech

2016-07-01

The genetics of eye colour has been extensively studied over the past few years, and the identified polymorphisms have been applied with marked success in the field of Forensic DNA Phenotyping. A picture that arises from evaluation of the currently available eye colour prediction markers shows that only the analysis of HERC2-OCA2 complex has similar effectiveness in different populations, while the predictive potential of other loci may vary significantly. Moreover, the role of gender in the explanation of human eye colour variation should not be neglected in some populations. In the present study, we re-investigated the data for 1020 Polish individuals and using neural networks and logistic regression methods explored predictive capacity of IrisPlex SNPs and gender in this population sample. In general, neural networks provided higher prediction accuracy comparing to logistic regression (AUC increase by 0.02-0.06). Four out of six IrisPlex SNPs were associated with eye colour in the studied population. HERC2 rs12913832, OCA2 rs1800407 and SLC24A4 rs12896399 were found to be the most important eye colour predictors (p < 0.007) while the effect of rs16891982 in SLC45A2 was less significant. Gender was found to be significantly associated with eye colour with males having ~1.5 higher odds for blue eye colour comparing to females (p = 0.002) and was ranked as the third most important factor in blue/non-blue eye colour determination. However, the implementation of gender into the developed prediction models had marginal and ambiguous impact on the overall accuracy of prediction confirming that the effect of gender on eye colour in this population is small. Our study indicated the advantage of neural networks in prediction modeling in forensics and provided additional evidence for population specific differences in the predictive importance of the IrisPlex SNPs and gender.

On the colour of wing scales in butterflies: iridescence and preferred orientation of single gyroid photonic crystals

PubMed Central

2017-01-01

Lycaenid butterflies from the genera Callophrys, Cyanophrys and Thecla have evolved remarkable biophotonic gyroid nanostructures within their wing scales that have only recently been replicated by nanoscale additive manufacturing. These nanostructures selectively reflect parts of the visible spectrum to give their characteristic non-iridescent, matte-green appearance, despite a distinct blue–green–yellow iridescence predicted for individual crystals from theory. It has been hypothesized that the organism must achieve its uniform appearance by growing crystals with some restrictions on the possible distribution of orientations, yet preferential orientation observed in Callophrys rubi confirms that this distribution need not be uniform. By analysing scanning electron microscope and optical images of 912 crystals in three wing scales, we find no preference for their rotational alignment in the plane of the scales. However, crystal orientation normal to the scale was highly correlated to their colour at low (conical) angles of view and illumination. This correlation enabled the use of optical images, each containing up to 104–105 crystals, for concluding the preferential alignment seen along the at the level of single scales, appears ubiquitous. By contrast, orientations were found to occur at no greater rate than that expected by chance. Above a critical cone angle, all crystals reflected bright green light indicating the dominant light scattering is due to the predicted band gap along the direction, independent of the domain orientation. Together with the natural variation in scale and wing shapes, we can readily understand the detailed mechanism of uniform colour production and iridescence suppression in these butterflies. It appears that the combination of preferential alignment normal to the wing scale, and uniform distribution within the plane is a near optimal solution for homogenizing the angular distribution of the band gap relative to the wings. Finally, the distributions of orientations, shapes, sizes and degree of order of crystals within single scales provide useful insights for understanding the mechanisms at play in the formation of these biophotonic nanostructures. PMID:28630678

Colour cyclic code for Brillouin distributed sensors

NASA Astrophysics Data System (ADS)

Le Floch, Sébastien; Sauser, Florian; Llera, Miguel; Rochat, Etienne

2015-09-01

For the first time, a colour cyclic coding (CCC) is theoretically and experimentally demonstrated for Brillouin optical time-domain analysis (BOTDA) distributed sensors. Compared to traditional intensity-modulated cyclic codes, the code presents an additional gain of √2 while keeping the same number of sequences as for a colour coding. A comparison with a standard BOTDA sensor is realized and validates the theoretical coding gain.

Psychophysiological evidence for the genuineness of swimming-style colour synaesthesia.

PubMed

Rothen, Nicolas; Nikolić, Danko; Jürgens, Uta Maria; Mroczko-Wąsowicz, Aleksandra; Cock, Josephine; Meier, Beat

2013-03-01

Recently, swimming-style colour synaesthesia was introduced as a new form of synaesthesia. A synaesthetic Stroop test was used to establish its genuineness. Since Stroop interference can occur for any type of overlearned association, in the present study we used a modified Stroop test and psychophysiological synaesthetic conditioning to further establish the genuineness of this form of synaesthesia. We compared the performance of a swimming-style colour synaesthete and a control who was trained on swimming-style colour associations. Our results showed that behavioural aspects of swimming-style colour synaesthesia can be mimicked in a trained control. Importantly, however, our results showed a psychophysiological conditioning effect for the synaesthete only. We discuss the theoretical relevance of swimming-style colour synaesthesia according to different models of synaesthesia. We conclude that swimming-style colour synaesthesia is a genuine form of synaesthesia, can be mimicked behaviourally in non-synaesthetes, and is best explained by a re-entrant feedback model. Copyright © 2012 Elsevier Inc. All rights reserved.

Oculomotor capture by colour singletons depends on intertrial priming.

PubMed

Becker, Stefanie I

2010-10-12

In visual search, an irrelevant colour singleton captures attention when the colour of the distractor changes across trials (e.g., from red to green), but not when the colour remains constant (Becker, 2007). The present study shows that intertrial changes of the distractor colour also modulate oculomotor capture: an irrelevant colour singleton distractor was only selected more frequently than the inconspicuous nontargets (1) when its features had switched (compared to the previous trial), or (2) when the distractor had been presented at the same position as the target on the previous trial. These results throw doubt on the notion that colour distractors capture attention and the eyes because of their high feature contrast, which is available at an earlier point in time than information about specific feature values. Instead, attention and eye movements are apparently controlled by a system that operates on feature-specific information, and gauges the informativity of nominally irrelevant features. Copyright © 2010 Elsevier Ltd. All rights reserved.

Metabolism variation and better storability of dark- versus light-coloured soybean (Glycine max L. Merr.) seeds.

PubMed

Liu, Jiang; Qin, Wen-Ting; Wu, Hai-Jun; Yang, Cai-Qiong; Deng, Jun-Cai; Iqbal, Nasir; Liu, Wei-Guo; Du, Jun-Bo; Shu, Kai; Yang, Feng; Wang, Xiao-Chun; Yong, Tai-Wen; Yang, Wen-Yu

2017-05-15

The effects of storage duration on the seed germination and metabolite profiling of soybean seeds with five different coloured coats were studied. Their germination, constituents and transcript expressions of isoflavones and free fatty acids (FFAs) were compared using chromatographic metabolomic profiling and transcriptome sequencing. The seed water content was characterized using nuclear magnetic resonance (NMR) relaxometry. Results showed that dark-coloured seeds were less inactivated than light-coloured seeds. The aglycone and β-glucoside concentrations of upstream constituents increased significantly, whereas the acetylglucosides and malonylglucosides of downstream constituents decreased with an increase in the storage period. FFAs increased considerably in the soybean seeds as a result of storage. These results indicate that dark-coloured soybean seeds have better storability than light-coloured seeds, and seed water content plays a role in seed inactivation. It was concluded that there are certain metabolic regularities that are associated with different coloured seed coats of soybeans under storage conditions. Copyright © 2016 Elsevier Ltd. All rights reserved.

An evaluation of the transferability of Munsell's colour notation methodology to modern inkjet printing technology

NASA Astrophysics Data System (ADS)

Olen, Melissa; Geisow, Adrian; Parraman, Carinna

2015-01-01

This paper examines the transferability of the Munsell system to modern inkjet colorants and printing technology following a similar approach to his original methods. While extensive research and development has gone into establishing methods for measuring and modelling the modern colour gamut, this study seeks to reintegrate the psychophysical and artistic principles used in Munsell's early colour studies with digital print. Contemporary inkjet printing, with ink sets containing a greater number of primary colorants, are significantly higher in chroma compared to the limited colorants available at the time of Munsell's original work. Following Munsell's design and implementation, our experiments replicate the use of Clerk-Maxwell's spinning disks in order to examine the effects of colour mixing with these expanded colour capacities, and to determine hue distribution and placement. This work revisits Munsell's project in light of known issues, and formulates questions about how we can reintegrate Munsell's approach for colour description and mixing into modern colour science, understanding, and potential application.

Analysis of brain activity and response to colour stimuli during learning tasks: an EEG study

NASA Astrophysics Data System (ADS)

Folgieri, Raffaella; Lucchiari, Claudio; Marini, Daniele

2013-02-01

The research project intends to demonstrate how EEG detection through BCI device can improve the analysis and the interpretation of colours-driven cognitive processes through the combined approach of cognitive science and information technology methods. To this end, firstly it was decided to design an experiment based on comparing the results of the traditional (qualitative and quantitative) cognitive analysis approach with the EEG signal analysis of the evoked potentials. In our case, the sensorial stimulus is represented by the colours, while the cognitive task consists in remembering the words appearing on the screen, with different combination of foreground (words) and background colours. In this work we analysed data collected from a sample of students involved in a learning process during which they received visual stimuli based on colour variation. The stimuli concerned both the background of the text to learn and the colour of the characters. The experiment indicated some interesting results concerning the use of primary (RGB) and complementary (CMY) colours.

Colours in black and white: the depiction of lightness and brightness in achromatic engravings before the invention of photography.

PubMed

Zavagno, Daniele; Massironi, Manfredo

2006-01-01

What is it like to see the world in black and white? In the pioneer days of cinema, when movies displayed grey worlds, was it true that no 'colours' were actually seen? Did every object seen in those projections appear grey in the same way? The answer is obviously no--people in those glorious days were seeing a world full of light, shadows, and objects in which colours were expressed in terms of lightness. But the marvels of grey worlds have not always been so richly displayed. Before the invention of photography, the depiction of scenes in black-and-white had to face some technical and perceptual challenges. We have studied the technical and perceptual constraints that XV-XVIII century engravers had to face in order to translate actual colours into shades of grey. An indeterminacy principle is considered, according to which artists had to prefer the representation of some object or scene features over others (for example brightness over lightness). The reasons for this lay between the kind of grey scale technically available and the kind of information used in the construction of 3-D scenes. With the invention of photography, photomechanical reproductions, and new printing solutions, artists had at their disposal a continuous grey scale that greatly reduces the constraints of the indeterminacy principle.

The diversity of the human hair colour assessed by visual scales and instrumental measurements. A worldwide survey.

PubMed

Lozano, I; Saunier, J B; Panhard, S; Loussouarn, G

2017-02-01

To study (i) the diversity of the natural colour of the human hair through both visual assessment of hair tone levels and colorimetric measurements of hair strands collected from 2057 human male and female volunteers, from 23 regions of the world and (ii) the correlation between visual assessments and colorimetric measurements. Hair strands were analysed by a spectrocolorimeter under the L*, a*, b* referential system and scored in vivo by experts before sampling, through standardized visual reference scales based on a 1-10 range. Results show that from a typological aspect, black or dark brown hairs largely predominate among studied ethnic groups, whereas Caucasian or derived populations exhibit the widest palette of medium to fair shades, partly explaining some past interbreeding among populations. Instrumental measurements clearly confirm that a given colour of a pigmented hair, at the exclusion of red hairs, is mostly governed by two components, L* and b*, from the L*, a*, b* reference system. The comparisons between visual assessments and instrumental data show that these appear closely linked. Darker hairs show close or subtle variations in L*, a*, b* parameters, making their individual colour differentiation calling for technical improvements in colorimetric measurements. The latter are likely governed by other physical factors such as shape, diameter and shine. © 2016 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Influences of age and maxillary anterior teeth status on patient's satisfaction with dental appearance and tooth colour.

PubMed

Lajnert, Vlatka; Pavičić, Daniela K; Gržić, Renata; Kovač, Zoran; Pahor, Dana; Kuis, Davor; Simonić-Kocijan, Sunčana; Antonić, Robert; Bakarčić, Danko

2012-06-01

To study the impact of age, gender, tooth colour and maxillary anterior teeth status on patient's satisfaction with their dental appearance. A total of 259 Caucasian subjects participated in the study (119 men, mean age 56 years; 140 women, mean age 61 years) divided into three age groups (young <35 age; middle aged 35-54 age; old ≥55 age). Their maxillary anterior teeth status was classified into three groups: (1) natural teeth (NTG) group; (2) composite filling group (CFG) and (3) porcelain-fused-to-metal fixed prosthodontic restoration group (FPDG). The participants judged appearance and tooth colour using a scale with three categories: completely dissatisfied, moderately dissatisfied and completely satisfied. Almost half of the participants were completely satisfied with their dental appearance and tooth colour. Half of the 'young' and 'middle-aged' participants with natural maxillary anterior teeth were completely satisfied and half of the 'old' participants were moderately satisfied with their dental appearance and tooth colour. The majority of participants with composite restorations (45-51%) were moderately satisfied with their dental appearance, one-third of 'young' and 'middle-aged' participants were moderately satisfied or dissatisfied with their tooth colour and more than 70% of older participants were dissatisfied with their tooth colour (p > 0.05). Satisfaction with the appearance of the maxillary anterior teeth differed both between individuals of different age and different dental status. © 2011 The Gerodontology Society and John Wiley & Sons A/S.

Comparative Assessment of Conventional Composites and Coloured Compomers in Permanent Molars of Children with Mixed Dentition: A Pilot Study

PubMed Central

Kohli, Divyata; Badakar, Chandrashekhar M; Vyavahare, Supriya S; Shah, Parin P; Gokhale, Niraj S; Patel, Punit M; Mundada, Madhura V

2017-01-01

Introduction Early treatment of carious lesions in children is important for the maintenance of oral health. Multicoloured restorations could be the impetus for an extremely nervous or defiant child to take dental treatment. Aim The aim of this study was to assess and compare the clinical success of conventional composites and coloured compomer material in first permanent molars of children with mixed dentition. Materials and Methods A total of sixty sites, divided into two groups, with thirty subjects in each group using split mouth design were chosen amongst patients reporting to Department of Pedodontics and Preventive Dentistry. In control group conventional composites were placed, similarly coloured compomers were placed in experimental group under standard operating protocol. Patients were recalled for assessment of clinical success amongst control as well as experimental group at regular intervals of one; three and six months follow up based on Modified Ryge’s Criteria. Statistical analysis was done using Chi-square test using SPSS version 20.0 (Chicago, USA). Results Both conventional composites and coloured compomers had comparable retention rates in terms of anatomical form, marginal integrity, secondary caries and marginal discolouration. Conclusion The coloured compomer material showed promising results in this six month follow up study in permanent molars and had properties comparable to that of conventional composites. PMID:28764297

The role of luminance and chromatic cues in emmetropisation.

PubMed

Rucker, Frances J

2013-05-01

At birth most, but not all eyes, are hyperopic. Over the course of the first few years of life the refraction gradually becomes close to zero through a process called emmetropisation. This process is not thought to require accommodation, though a lag of accommodation has been implicated in myopia development, suggesting that the accuracy of accommodation is an important factor. This review will cover research on accommodation and emmetropisation that relates to the ability of the eye to use colour and luminance cues to guide the responses. There are three ways in which changes in luminance and colour contrast could provide cues: (1) The eye could maximize luminance contrast. Monochromatic light experiments have shown that the human eye can accommodate and animal eyes can emmetropise using changes in luminance contrast alone. However, by reducing the effectiveness of luminance cues in monochromatic and white light by introducing astigmatism, or by reducing light intensity, investigators have revealed that the eye also uses colour cues in emmetropisation. (2) The eye could compare relative cone contrast to derive the sign of defocus information from colour cues. Experiments involving simulations of the retinal image with defocus have shown that relative cone contrast can provide colour cues for defocus in accommodation and emmetropisation. In the myopic simulation the contrast of the red component of a sinusoidal grating was higher than that of the green and blue component and this caused relaxation of accommodation and reduced eye growth. In the hyperopic simulation the contrast of the blue component was higher than that of the green and red components and this caused increased accommodation and increased eye growth. (3) The eye could compare the change in luminance and colour contrast as the eye changes focus. An experiment has shown that changes in colour or luminance contrast can provide cues for defocus in emmetropisation. When the eye is exposed to colour flicker the eye grows almost twice as much, and becomes more myopic, compared to when the eye is exposed to luminance flicker. Neural responses of the luminance and colour mechanisms direct accommodation and emmetropisation mechanisms to different focal planes. Therefore, it is likely that the set point of refraction and accommodation is dependent on the sensitivity of the eye to changes in spatial and temporal, colour and luminance contrast. Ophthalmic & Physiological Optics © 2013 The College of Optometrists.

Sealant retention is better assessed through colour photographs than through the replica and the visual examination methods.

PubMed

Hu, Xuan; Fan, Mingwan; Rong, Wensheng; Lo, Edward C M; Bronkhorst, Ewald; Frencken, Jo E

2014-08-01

The aim of this study was to test the hypothesis that the colour photograph method has a higher level of validity for assessing sealant retention than the visual clinical examination and replica methods. Sealed molars were assessed by two evaluators. The scores for the three methods were compared against consensus scores derived through assessing retention from scanning electron microscopy images (reference standard). The presence/absence (survival) of retained sealants on occlusal surfaces was determined according to the traditional and modified categorizations of retention. Sensitivity, specificity, and Youden-index scores were calculated. Sealant retention assessment scores for visual clinical examinations and for colour photographs were compared with those of the reference standard on 95 surfaces, and sealant retention assessment scores for replicas were compared with those of the reference standard on 33 surfaces. The highest mean Youden-index score for the presence/absence of sealant material was observed for the colour photograph method, followed by that for the replica method; the visual clinical examination method scored lowest. The mean Youden-index score for the survival of retained sealants was highest for the colour photograph method for both the traditional (0.882) and the modified (0.768) categories of sealant retention, whilst the visual clinical examination method had the lowest Youden-index score for these categories (0.745 and 0.063, respectively). The colour photograph method had a higher validity than the replica and the visual examination methods for assessing sealant retention. © 2014 Eur J Oral Sci.

Texture variations suppress suprathreshold brightness and colour variations.

PubMed

Schofield, Andrew J; Kingdom, Frederick A A

2014-01-01

Discriminating material changes from illumination changes is a key function of early vision. Luminance cues are ambiguous in this regard, but can be disambiguated by co-incident changes in colour and texture. Thus, colour and texture are likely to be given greater prominence than luminance for object segmentation, and better segmentation should in turn produce stronger grouping. We sought to measure the relative strengths of combined luminance, colour and texture contrast using a suprathreshhold, psychophysical grouping task. Stimuli comprised diagonal grids of circular patches bordered by a thin black line and contained combinations of luminance decrements with either violet, red, or texture increments. There were two tasks. In the Separate task the different cues were presented separately in a two-interval design, and participants indicated which interval contained the stronger orientation structure. In the Combined task the cues were combined to produce competing orientation structure in a single image. Participants had to indicate which orientation, and therefore which cue was dominant. Thus we established the relative grouping strength of each cue pair presented separately, and compared this to their relative grouping strength when combined. In this way we observed suprathreshold interactions between cues and were able to assess cue dominance at ecologically relevant signal levels. Participants required significantly more luminance and colour compared to texture contrast in the Combined compared to Separate conditions (contrast ratios differed by about 0.1 log units), showing that suprathreshold texture dominates colour and luminance when the different cues are presented in combination.

Parental infant jaundice colour card design successfully validated by comparing it with total serum bilirubin.

PubMed

Xue, Guo-Chang; Ren, Ming-Xing; Shen, Lin-Na; Zhang, Li-Wen

2016-12-01

We designed a jaundice colour card that could be used by the parents of neonates and validated it by comparing it with total serum bilirubin levels. There were 106 term Chinese neonates in the study. The majority weighed between 2500 g and 3499 g (63%) and had a gestational age of 37-40 weeks (77%). The jaundice colour card and photometric determination were used to screen for neonatal jaundice and compared with serum bilirubin. The bilirubin levels were measured by mothers using the jaundice colour card, and 67% of the measurements were taken at 11-20 days (range 3-30). The measurements at the infant's forehead, cheek and sternum showed strong correlations with total serum bilirubin. The mean differences between the total serum bilirubin and the jaundice colour card measurements from the forehead, cheek and sternum were 1.9 mg/dL, 0.3 mg/dL and 1.5 mg/dL, respectively. When total serum bilirubin >13 mg/dL was used as the cut-off point, the areas under the receiver operating characteristics curves were 0.934 for the forehead, 0.985 for the cheek and 0.966 for the sternum. We established the validity of the jaundice colour card as a parental measurement tool for jaundice in Chinese neonates, and the cheek was the best measurement site. ©2016 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.

Long-lived, colour-triplet scalars from unnaturalness

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barnard, James; Cox, Peter; Gherghetta, Tony

We study that long-lived, colour-triplet scalars are a generic prediction of unnatural, or split, composite Higgs models where the spontaneous global-symmetry breaking scale f ≳ 10TeV and an unbroken SU(5) symmetry is preserved. Since the triplet scalars are pseudo Nambu- Goldstone bosons they are split from the much heavier composite-sector resonances and are the lightest exotic, coloured states. This makes them ideal to search for at colliders. Due to discrete symmetries the triplet scalar decays via a dimension-six term and given the large suppression scale f is often metastable. We show that existing searches for collider-stable R-hadrons from Run-I atmore » the LHC forbid a triplet scalar mass below 845 GeV, whereas with 300 fb -1 at 13TeV triplet scalar masses up to 1.4TeV can be discovered. For shorter lifetimes displaced-vertex searches provide a discovery reach of up to 1.8TeV. Also, we present exclusion and discovery reaches of future hadron colliders as well as indirect limits that arise from modi cations of the Higgs couplings.« less

Long-lived, colour-triplet scalars from unnaturalness

DOE PAGES

Barnard, James; Cox, Peter; Gherghetta, Tony; ...

2016-03-01

We study that long-lived, colour-triplet scalars are a generic prediction of unnatural, or split, composite Higgs models where the spontaneous global-symmetry breaking scale f ≳ 10TeV and an unbroken SU(5) symmetry is preserved. Since the triplet scalars are pseudo Nambu- Goldstone bosons they are split from the much heavier composite-sector resonances and are the lightest exotic, coloured states. This makes them ideal to search for at colliders. Due to discrete symmetries the triplet scalar decays via a dimension-six term and given the large suppression scale f is often metastable. We show that existing searches for collider-stable R-hadrons from Run-I atmore » the LHC forbid a triplet scalar mass below 845 GeV, whereas with 300 fb -1 at 13TeV triplet scalar masses up to 1.4TeV can be discovered. For shorter lifetimes displaced-vertex searches provide a discovery reach of up to 1.8TeV. Also, we present exclusion and discovery reaches of future hadron colliders as well as indirect limits that arise from modi cations of the Higgs couplings.« less

Spectral reflectance properties of iridescent pierid butterfly wings.

PubMed

Wilts, Bodo D; Pirih, Primož; Stavenga, Doekele G

2011-06-01

The wings of most pierid butterflies exhibit a main, pigmentary colouration: white, yellow or orange. The males of many species have in restricted areas of the wing upper sides a distinct structural colouration, which is created by stacks of lamellae in the ridges of the wing scales, resulting in iridescence. The amplitude of the reflectance is proportional to the number of lamellae in the ridge stacks. The angle-dependent peak wavelength of the observed iridescence is in agreement with classical multilayer theory. The iridescence is virtually always in the ultraviolet wavelength range, but some species have a blue-peaking iridescence. The spectral properties of the pigmentary and structural colourations are presumably tuned to the spectral sensitivities of the butterflies' photoreceptors.

Prevalence of Colour Vision Anomalies Amongst Dental Professionals and its Effect on Shade Matching of Teeth

PubMed Central

Maini, Anuj Paul; Wangoo, Anuj; Singh, Sukhman; Mehar, Damanpreet Kaur

2017-01-01

Abstract Introduction The success of a restoration is dependent on accurate shade matching of teeth leading to studies evaluating the factors affecting the perception of shades. Colour vision anomalies including colour blindness have been found to exist in the population and it has been thought to be a potential factor affecting the colour perception ability. Aim The present study was done to evaluate the prevalence of colour vision anomalies and its effect on matching of shades of teeth. Materials and Methods A total of 147 dental professionals were randomly selected for the study and were first tested for visual acuity using the Snellen’s Eye Chart so as to carry on the study with only those operators who had a vision of 6/6. Then, the Ishihara’s colour charts were used to test the operators for colour vision handicap. In the last stage of the study, test for accuracy of shade selection was done using the Vitapan Classical shade guide. The shade guide tabs were covered to avoid bias. Percentage was used to calculate the prevalence of colour vision handicap and its effect on matching of shades of teeth as compared to normal vision, which was evaluated using Chi square test. Results Nineteen operators had colour vision anomalies out of hundred operators and only two operators presented with colour blindness. Colour vision anomaly was more prevalent than colour blindness and it was also found that it was more prevalent in males than females. The difference between the accuracy of shade matching between the operators with normal vision and colour vision defect and operators with normal vision and colour blindness was statistically not significant. Conclusion Colour blindness and colour vision handicap are rare conditions, with the latter being more common in the population. According to our study, it was concluded that no statistically significant difference existed amongst the operators with normal vision and colour vision anomaly or operators with normal vision and colour blindness during the matching of shades of teeth. PMID:28274040

Grape colour phenotyping: development of a method based on the reflectance spectrum.

PubMed

Rustioni, Laura; Basilico, Roberto; Fiori, Simone; Leoni, Alessandra; Maghradze, David; Failla, Osvaldo

2013-01-01

The colour of fruit is an important quality factor for cultivar classification and phenotyping techniques. Besides the subjective visual evaluation, new instruments and techniques can be used. This work aims at developping an objective, fast, easy and non-destructive method as a useful support for evaluating grapes' colour under different cultural and environmental conditions, as well as for breeding process and germplasm evaluation, supporting the plant characterization and the biodiversity preservation. Colours of 120 grape varieties were studied using reflectance spectra. The classification was realized using cluster and discriminant analysis. Reflectance of the whole berries surface was also compared with absorption properties of single skin extracts. A phenotyping method based on the reflectance spectra was developed, producing reliable colour classifications. A cultivar-independent index for pigment content evaluation has also been obtained. This work allowed the classification of the berry colour using an objective method. Copyright © 2013 John Wiley & Sons, Ltd.

Influence of skin colour on diagnostic accuracy of the jaundice meter JM 103 in newborns.

PubMed

Samiee-Zafarghandy, S; Feberova, J; Williams, K; Yasseen, A S; Perkins, S L; Lemyre, B

2014-11-01

To assess the diagnostic accuracy of the JM 103 as a screening tool for neonatal jaundice and explore differential effects based on skin colour. We prospectively compared the transcutaneous bilirubin (TcB) and serum bilirubin (TSB) measurements of newborns over a 3 month-period. Skin colour was assigned via reference colour swatches. Diagnostic measures of the TcB/TSB comparison were made and clinically relevant TcB cut-off values were determined for each skin colour group. 451 infants (51 light, 326 medium and 74 dark skin colour) were recruited. The association between TcB and TSB was high for all skin colours (rs>0.9). The Bland-Altman analysis showed an absolute mean difference between the two measures of 13.3±26.4 µmol/L with broad limits of agreement (-39.4-66.0 µmol/L), with TcB underestimating TSB in light and medium skin colours and overestimating in dark skin colour. Diagnostic measures were also consistently high across skin colours, with no clinically significant differences observed. The JM 103 is a useful screening tool to identify infants in need of serum bilirubin, regardless of skin colour. The effect of skin colour on the accuracy of this device at high levels of serum bilirubin could not be assessed fully due to small numbers in the light and dark groups. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Colour calibration of a laboratory computer vision system for quality evaluation of pre-sliced hams.

PubMed

Valous, Nektarios A; Mendoza, Fernando; Sun, Da-Wen; Allen, Paul

2009-01-01

Due to the high variability and complex colour distribution in meats and meat products, the colour signal calibration of any computer vision system used for colour quality evaluations, represents an essential condition for objective and consistent analyses. This paper compares two methods for CIE colour characterization using a computer vision system (CVS) based on digital photography; namely the polynomial transform procedure and the transform proposed by the sRGB standard. Also, it presents a procedure for evaluating the colour appearance and presence of pores and fat-connective tissue on pre-sliced hams made from pork, turkey and chicken. Our results showed high precision, in colour matching, for device characterization when the polynomial transform was used to match the CIE tristimulus values in comparison with the sRGB standard approach as indicated by their ΔE(ab)(∗) values. The [3×20] polynomial transfer matrix yielded a modelling accuracy averaging below 2.2 ΔE(ab)(∗) units. Using the sRGB transform, high variability was appreciated among the computed ΔE(ab)(∗) (8.8±4.2). The calibrated laboratory CVS, implemented with a low-cost digital camera, exhibited reproducible colour signals in a wide range of colours capable of pinpointing regions-of-interest and allowed the extraction of quantitative information from the overall ham slice surface with high accuracy. The extracted colour and morphological features showed potential for characterizing the appearance of ham slice surfaces. CVS is a tool that can objectively specify colour and appearance properties of non-uniformly coloured commercial ham slices.

Best not to bet on the horserace: A comment on Forrin and MacLeod (2017) and a relevant stimulus-response compatibility view of colour-word contingency learning asymmetries.

PubMed

Schmidt, James R

2018-02-01

One powerfully robust method for the study of human contingency learning is the colour-word contingency learning paradigm. In this task, participants respond to the print colour of neutral words, each of which is presented most often in one colour. The contingencies between words and colours are learned, as indicated by faster and more accurate responses when words are presented in their expected colour relative to an unexpected colour. In a recent report, Forrin and MacLeod (2017b, Memory & Cognition) asked to what extent this performance (i.e., response time) measure of learning might depend on the relative speed of processing of the word and the colour. With keypress responses, learning effects were comparable when responding to the word and to the colour (contrary to predictions). However, an asymmetry appeared in a second experiment with vocal responses, with a contingency effect only present for colour identification. In a third experiment, the colour was preexposed, and contingency effects were again roughly symmetrical. In their report, they suggested that a simple speed-of-processing (or "horserace") model might explain when contingency effects are observed in colour and word identification. In the present report, an alternative view is presented. In particular, it is argued that the results are best explained by appealing to the notion of relevant stimulus-response compatibility, which also resolves discrepancies between horserace model predictions and participant results. The article presents simulations with the Parallel Episodic Processing model to demonstrate this case.

The Overdense Environments of WISE-selected, ultra-luminous, high-redshift AGN in the submillimetre

NASA Astrophysics Data System (ADS)

Jones, Suzy F.

2017-11-01

The environments around WISE-selected hot dust obscured galaxies (Hot DOGs) and WISE/radio-selected active galactic nuclei (AGNs) at average redshifts of z = 2.7 and z = 1.7, respectively, were found to have overdensities of companion submillimetre-selected sources. The overdensities were of ˜ 2 - 3 and ˜ 5 - 6 , respectively, compared with blank field submm surveys. The space densities in both samples were found to be overdense compared to normal star-forming galaxies and submillimetre galaxies (SMGs). All of the companion sources have consistent mid-IR colours and mid-IR to submm ratios to SMGs. Monte Carlo simulations show no angular correlation, which could indicate protoclusters on scales larger than the SCUBA-2 1.5 arcmin scale maps. WISE-selected AGNs appear to be good indicators of overdense areas of active galaxies at high redshift.

Colour analysis of the equine endometrium: comparison of spectrophotometry and computer-assisted analysis of photographs within the L*a*b* colour space system.

PubMed

Neuhauser, S; Handler, J

2013-09-01

The aims of this study were to compare two different methods of quantifying the colour of the luminal surface of the equine endometrium and to relate the results to histopathological evidence of inflammation and fibrosis. The mucosal surfaces of 17 equine uteri obtained from an abattoir were assessed using a spectrophotometer and by computer-assisted analysis of photographs. Values were converted into L(*)a(*)b(*) colour space. Although there was significant correlation between the two methods of quantification, variations in 'brightness', 'red' and 'yellow' values were noted. Within a given uterus, measurements using the spectrophotometer did not differ significantly. Using photographic analysis, brightness differed between horns, although no differences in chromaticity were found. Histopathological classification of changes within endometria corresponded to measured differences in colour. Extensive fibrosis was associated with increased brightness and decreased chromaticity using both methods. Inflammation correlated with reduced chromaticity, when measured by spectrophotometry, and with reduced brightness and yellow values, when assessed photographically. For this technique to gain wider acceptance as a diagnostic tool, e.g. for the endoscopic evaluation of uterine mucosae in vivo, standardised illumination techniques will be required so that colours can be compared and interpreted accurately. Copyright © 2013 Elsevier Ltd. All rights reserved.

Pronounced Seasonal Changes in the Movement Ecology of a Highly Gregarious Central-Place Forager, the African Straw-Coloured Fruit Bat (Eidolon helvum)

PubMed Central

Fahr, Jakob; Abedi-Lartey, Michael; Esch, Thomas; Machwitz, Miriam; Suu-Ire, Richard; Wikelski, Martin; Dechmann, Dina K. N.

2015-01-01

Background Straw-coloured fruit bats (Eidolon helvum) migrate over vast distances across the African continent, probably following seasonal bursts of resource availability. This causes enormous fluctuations in population size, which in turn may influence the bats’ impact on local ecosystems. We studied the movement ecology of this central-place forager with state-of-the-art GPS/acceleration loggers and concurrently monitored the seasonal fluctuation of the colony in Accra, Ghana. Habitat use on the landscape scale was assessed with remote sensing data as well as ground-truthing of foraging areas. Principal Findings During the wet season population low (~ 4000 individuals), bats foraged locally (3.5–36.7 km) in urban areas with low tree cover. Major food sources during this period were fruits of introduced trees. Foraging distances almost tripled (24.1–87.9 km) during the dry season population peak (~ 150,000 individuals), but this was not compensated for by reduced resting periods. Dry season foraging areas were random with regard to urban footprint and tree cover, and food consisted almost exclusively of nectar and pollen of native trees. Conclusions and Significance Our study suggests that straw-coloured fruit bats disperse seeds in the range of hundreds of meters up to dozens of kilometres, and pollinate trees for up to 88 km. Straw-coloured fruit bats forage over much larger distances compared to most other Old World fruit bats, thus providing vital ecosystem services across extensive landscapes. We recommend increased efforts aimed at maintaining E. helvum populations throughout Africa since their keystone role in various ecosystems is likely to increase due to the escalating loss of other seed dispersers as well as continued urbanization and habitat fragmentation. PMID:26465139

Pronounced Seasonal Changes in the Movement Ecology of a Highly Gregarious Central-Place Forager, the African Straw-Coloured Fruit Bat (Eidolon helvum).

PubMed

Fahr, Jakob; Abedi-Lartey, Michael; Esch, Thomas; Machwitz, Miriam; Suu-Ire, Richard; Wikelski, Martin; Dechmann, Dina K N

2015-01-01

Straw-coloured fruit bats (Eidolon helvum) migrate over vast distances across the African continent, probably following seasonal bursts of resource availability. This causes enormous fluctuations in population size, which in turn may influence the bats' impact on local ecosystems. We studied the movement ecology of this central-place forager with state-of-the-art GPS/acceleration loggers and concurrently monitored the seasonal fluctuation of the colony in Accra, Ghana. Habitat use on the landscape scale was assessed with remote sensing data as well as ground-truthing of foraging areas. During the wet season population low (~ 4000 individuals), bats foraged locally (3.5-36.7 km) in urban areas with low tree cover. Major food sources during this period were fruits of introduced trees. Foraging distances almost tripled (24.1-87.9 km) during the dry season population peak (~ 150,000 individuals), but this was not compensated for by reduced resting periods. Dry season foraging areas were random with regard to urban footprint and tree cover, and food consisted almost exclusively of nectar and pollen of native trees. Our study suggests that straw-coloured fruit bats disperse seeds in the range of hundreds of meters up to dozens of kilometres, and pollinate trees for up to 88 km. Straw-coloured fruit bats forage over much larger distances compared to most other Old World fruit bats, thus providing vital ecosystem services across extensive landscapes. We recommend increased efforts aimed at maintaining E. helvum populations throughout Africa since their keystone role in various ecosystems is likely to increase due to the escalating loss of other seed dispersers as well as continued urbanization and habitat fragmentation.

From silk to satellite: half a century of ocean colour anomalies in the Northeast Atlantic.

PubMed

Raitsos, Dionysios E; Pradhan, Yaswant; Lavender, Samantha J; Hoteit, Ibrahim; McQuatters-Gollop, Abigail; Reid, Phillip C; Richardson, Anthony J

2014-07-01

Changes in phytoplankton dynamics influence marine biogeochemical cycles, climate processes, and food webs, with substantial social and economic consequences. Large-scale estimation of phytoplankton biomass was possible via ocean colour measurements from two remote sensing satellites - the Coastal Zone Colour Scanner (CZCS, 1979-1986) and the Sea-viewing Wide Field-of-view Sensor (SeaWiFS, 1998-2010). Due to the large gap between the two satellite eras and differences in sensor characteristics, comparison of the absolute values retrieved from the two instruments remains challenging. Using a unique in situ ocean colour dataset that spans more than half a century, the two satellite-derived chlorophyll-a (Chl-a) eras are linked to assess concurrent changes in phytoplankton variability and bloom timing over the Northeast Atlantic Ocean and North Sea. Results from this unique re-analysis reflect a clear increasing pattern of Chl-a, a merging of the two seasonal phytoplankton blooms producing a longer growing season and higher seasonal biomass, since the mid-1980s. The broader climate plays a key role in Chl-a variability as the ocean colour anomalies parallel the oscillations of the Northern Hemisphere Temperature (NHT) since 1948. © 2013 John Wiley & Sons Ltd.

Colour-producing β-keratin nanofibres in blue penguin (Eudyptula minor) feathers

PubMed Central

D'Alba, Liliana; Saranathan, Vinodkumar; Clarke, Julia A.; Vinther, Jakob A.; Prum, Richard O.; Shawkey, Matthew D.

2011-01-01

The colours of living organisms are produced by the differential absorption of light by pigments (e.g. carotenoids, melanins) and/or by the physical interactions of light with biological nanostructures, referred to as structural colours. Only two fundamental morphologies of non-iridescent nanostructures are known in feathers, and recent work has proposed that they self-assemble by intracellular phase separation processes. Here, we report a new biophotonic nanostructure in the non-iridescent blue feather barbs of blue penguins (Eudyptula minor) composed of parallel β-keratin nanofibres organized into densely packed bundles. Synchrotron small angle X-ray scattering and two-dimensional Fourier analysis of electron micrographs of the barb nanostructure revealed short-range order in the organization of fibres at the appropriate size scale needed to produce the observed colour by coherent scattering. These two-dimensional quasi-ordered penguin nanostructures are convergent with similar arrays of parallel collagen fibres in avian and mammalian skin, but constitute a novel morphology for feathers. The identification of a new class of β-keratin nanostructures adds significantly to the known mechanisms of colour production in birds and suggests additional complexity in their self-assembly. PMID:21307042

Colour-producing [beta]-keratin nanofibres in blue penguin (Eudyptula minor) feathers

DOE Office of Scientific and Technical Information (OSTI.GOV)

D; Alba, Liliana; Saranathan, Vinodkumar

2012-03-26

The colours of living organisms are produced by the differential absorption of light by pigments (e.g. carotenoids, melanins) and/or by the physical interactions of light with biological nanostructures, referred to as structural colours. Only two fundamental morphologies of non-iridescent nanostructures are known in feathers, and recent work has proposed that they self-assemble by intracellular phase separation processes. Here, we report a new biophotonic nanostructure in the non-iridescent blue feather barbs of blue penguins (Eudyptula minor) composed of parallel {beta}-keratin nanofibres organized into densely packed bundles. Synchrotron small angle X-ray scattering and two-dimensional Fourier analysis of electron micrographs of the barbmore » nanostructure revealed short-range order in the organization of fibres at the appropriate size scale needed to produce the observed colour by coherent scattering. These two-dimensional quasi-ordered penguin nanostructures are convergent with similar arrays of parallel collagen fibres in avian and mammalian skin, but constitute a novel morphology for feathers. The identification of a new class of {beta}-keratin nanostructures adds significantly to the known mechanisms of colour production in birds and suggests additional complexity in their self-assembly.« less

A Rapid Colorimetric Method Reveals Fraudulent Substitutions in Sea Urchin Roe Marketed in Sardinia (Italy).

PubMed

Meloni, Domenico; Spina, Antonio; Satta, Gianluca; Chessa, Vittorio

2016-06-25

In recent years, besides the consumption of fresh sea urchin specimens, the demand of minimally-processed roe has grown considerably. This product has made frequent consumption in restaurants possible and frauds are becoming widespread with the partial replacement of sea urchin roe with surrogates that are similar in colour. One of the main factors that determines the quality of the roe is its colour and small differences in colour scale cannot be easily discerned by the consumers. In this study we have applied a rapid colorimetric method for reveal the fraudulent partial substitution of semi-solid sea urchin roe with liquid egg yolk. Objective assessment of whiteness (L*), redness (a*), yellowness (b*), hue (h*), and chroma (C*) was carried out with a digital spectrophotometer using the CIE L*a*b* colour measurement system. The colorimetric method highlighted statistically significant differences among sea urchin roe and liquid egg yolk that could be easily discerned quantitatively.

Towards quantifying the aesthetic outcomes of breast cancer treatment: comparison of clinical photography and colorimetry.

PubMed

Kim, Min Soon; Rodney, William N; Cooper, Tara; Kite, Chris; Reece, Gregory P; Markey, Mia K

2009-02-01

Scarring is a significant cause of dissatisfaction for women who undergo breast surgery. Scar tissue may be clinically distinguished from normal skin by aberrant colour, rough surface texture, increased thickness (hypertrophy) and firmness. Colorimeters or spectrophotometers can be used to quantitatively assess scar colour, but they require direct patient interaction and can cost thousands of dollars. By comparison, digital photography is already in widespread use to document clinical outcomes and requires less patient interaction. Thus, assessment of scar coloration by digital photography is an attractive alternative. The goal of this study was to compare colour measurements obtained by digital photography and colorimetry. Agreements between photographic and colorimetric measurements of colour were evaluated. Experimental conditions were controlled by performing measurements on artificial scars created by a make-up artist. The colorimetric measurements of the artificial scars were compared with those reported in the literature for real scars in order to confirm the validity of this approach. We assessed the agreement between the colorimetric and photographic measurements of colour using a hypothesis test for equivalence, the intraclass correlation coefficient and the Bland-Altman method. Overall, good agreement was obtained for three parameters (L*a*b*) measured by colorimetry and photography from the results of three statistical analyses. Colour measurements obtained by digital photography were equivalent to those obtained using colorimetry. Thus, digital photography is a reliable, cost-effective measurement method of skin colour and should be further investigated for quantitative analysis of surgical outcomes.

Investigating Neuromagnetic Brain Responses against Chromatic Flickering Stimuli by Wavelet Entropies

PubMed Central

Bhagat, Mayank; Bhushan, Chitresh; Saha, Goutam; Shimjo, Shinsuke; Watanabe, Katsumi; Bhattacharya, Joydeep

2009-01-01

Background Photosensitive epilepsy is a type of reflexive epilepsy triggered by various visual stimuli including colourful ones. Despite the ubiquitous presence of colorful displays, brain responses against different colour combinations are not properly studied. Methodology/Principal Findings Here, we studied the photosensitivity of the human brain against three types of chromatic flickering stimuli by recording neuromagnetic brain responses (magnetoencephalogram, MEG) from nine adult controls, an unmedicated patient, a medicated patient, and two controls age-matched with patients. Dynamical complexities of MEG signals were investigated by a family of wavelet entropies. Wavelet entropy is a newly proposed measure to characterize large scale brain responses, which quantifies the degree of order/disorder associated with a multi-frequency signal response. In particular, we found that as compared to the unmedicated patient, controls showed significantly larger wavelet entropy values. We also found that Renyi entropy is the most powerful feature for the participant classification. Finally, we also demonstrated the effect of combinational chromatic sensitivity on the underlying order/disorder in MEG signals. Conclusions/Significance Our results suggest that when perturbed by potentially epileptic-triggering stimulus, healthy human brain manages to maintain a non-deterministic, possibly nonlinear state, with high degree of disorder, but an epileptic brain represents a highly ordered state which making it prone to hyper-excitation. Further, certain colour combination was found to be more threatening than other combinations. PMID:19779630

Investigating neuromagnetic brain responses against chromatic flickering stimuli by wavelet entropies.

PubMed

Bhagat, Mayank; Bhushan, Chitresh; Saha, Goutam; Shimjo, Shinsuke; Watanabe, Katsumi; Bhattacharya, Joydeep

2009-09-25

Photosensitive epilepsy is a type of reflexive epilepsy triggered by various visual stimuli including colourful ones. Despite the ubiquitous presence of colorful displays, brain responses against different colour combinations are not properly studied. Here, we studied the photosensitivity of the human brain against three types of chromatic flickering stimuli by recording neuromagnetic brain responses (magnetoencephalogram, MEG) from nine adult controls, an unmedicated patient, a medicated patient, and two controls age-matched with patients. Dynamical complexities of MEG signals were investigated by a family of wavelet entropies. Wavelet entropy is a newly proposed measure to characterize large scale brain responses, which quantifies the degree of order/disorder associated with a multi-frequency signal response. In particular, we found that as compared to the unmedicated patient, controls showed significantly larger wavelet entropy values. We also found that Renyi entropy is the most powerful feature for the participant classification. Finally, we also demonstrated the effect of combinational chromatic sensitivity on the underlying order/disorder in MEG signals. Our results suggest that when perturbed by potentially epileptic-triggering stimulus, healthy human brain manages to maintain a non-deterministic, possibly nonlinear state, with high degree of disorder, but an epileptic brain represents a highly ordered state which making it prone to hyper-excitation. Further, certain colour combination was found to be more threatening than other combinations.

Cultural transmission results in convergence towards colour term universals

PubMed Central

Xu, Jing; Dowman, Mike; Griffiths, Thomas L.

2013-01-01

As in biological evolution, multiple forces are involved in cultural evolution. One force is analogous to selection, and acts on differences in the fitness of aspects of culture by influencing who people choose to learn from. Another force is analogous to mutation, and influences how culture changes over time owing to errors in learning and the effects of cognitive biases. Which of these forces need to be appealed to in explaining any particular aspect of human cultures is an open question. We present a study that explores this question empirically, examining the role that the cognitive biases that influence cultural transmission might play in universals of colour naming. In a large-scale laboratory experiment, participants were shown labelled examples from novel artificial systems of colour terms and were asked to classify other colours on the basis of those examples. The responses of each participant were used to generate the examples seen by subsequent participants. By simulating cultural transmission in the laboratory, we were able to isolate a single evolutionary force—the effects of cognitive biases, analogous to mutation—and examine its consequences. Our results show that this process produces convergence towards systems of colour terms similar to those seen across human languages, providing support for the conclusion that the effects of cognitive biases, brought out through cultural transmission, can account for universals in colour naming. PMID:23486436

Confounding environmental colour and distribution shape leads to underestimation of population extinction risk.

PubMed

Fowler, Mike S; Ruokolainen, Lasse

2013-01-01

The colour of environmental variability influences the size of population fluctuations when filtered through density dependent dynamics, driving extinction risk through dynamical resonance. Slow fluctuations (low frequencies) dominate in red environments, rapid fluctuations (high frequencies) in blue environments and white environments are purely random (no frequencies dominate). Two methods are commonly employed to generate the coloured spatial and/or temporal stochastic (environmental) series used in combination with population (dynamical feedback) models: autoregressive [AR(1)] and sinusoidal (1/f) models. We show that changing environmental colour from white to red with 1/f models, and from white to red or blue with AR(1) models, generates coloured environmental series that are not normally distributed at finite time-scales, potentially confounding comparison with normally distributed white noise models. Increasing variability of sample Skewness and Kurtosis and decreasing mean Kurtosis of these series alter the frequency distribution shape of the realised values of the coloured stochastic processes. These changes in distribution shape alter patterns in the probability of single and series of extreme conditions. We show that the reduced extinction risk for undercompensating (slow growing) populations in red environments previously predicted with traditional 1/f methods is an artefact of changes in the distribution shapes of the environmental series. This is demonstrated by comparison with coloured series controlled to be normally distributed using spectral mimicry. Changes in the distribution shape that arise using traditional methods lead to underestimation of extinction risk in normally distributed, red 1/f environments. AR(1) methods also underestimate extinction risks in traditionally generated red environments. This work synthesises previous results and provides further insight into the processes driving extinction risk in model populations. We must let the characteristics of known natural environmental covariates (e.g., colour and distribution shape) guide us in our choice of how to best model the impact of coloured environmental variation on population dynamics.

Investigating the sources of sediment in a Canadian agricultural watershed using a colour-based fingerprinting technique

NASA Astrophysics Data System (ADS)

Barthod, Louise; Lobb, David; Owens, Philip; Martinez-Carreras, Nuria; Koiter, Alexander; Petticrew, Ellen; McCullough, Gregory

2014-05-01

The development of beneficial management practises to minimize adverse impacts of agriculture on soil and water quality requires information on the sources of sediment at the watershed scale. Sediment fingerprinting allows for the determination of sediment sources and apportionment of their contribution within a watershed, using unique physical, radiochemical or biogeochemical properties, or fingerprints, of the potential sediment sources. The use of sediment colour as a fingerprint is an emerging technique that can provide a rapid and inexpensive means of investigating sediment sources. This technique is currently being utilized to determine sediment sources within the South Tobacco Creek Watershed, an agricultural watershed located in the Canadian prairies (south-central Manitoba). Suspended sediment and potential source (topsoil, channel bank and shale bedrock material) samples were collected between 2009 and 2011 at six locations along the main stem of the creek. Sample colour was quantified from diffuse reflectance spectrometry measurements over the visible wavelength range using a spectroradiometer (ASD Field Spec Pro, 400-2500 nm). Sixteen colour coefficients were derived from several colour space models (CIE XYZ, CIE xyY, CIE Lab, CIE Luv, CIE Lch, Landsat RGB, Redness Index). The individual discrimination power of the colour coefficients, after passing several prerequisite tests (e.g., linearly additive behaviour), was assessed using discriminant function analysis. A stepwise discriminant analysis, based on the Wilk's lambda criterion, was then performed in order to determine the best-suited colour coefficient fingerprints which maximized the discrimination between the potential sources. The selected fingerprints classified the source samples in the correct category 86% of the time. The misclassification is due to intra-source variability and source overlap which can lead to higher uncertainty in sediment source apportionment. The selected fingerprints were then included in a Bayesian mixing model using Monte-Carlo simulation (Stable Isotope Analysis in R, SIAR) in order to apportion the contribution of the different sources to the sediment collected at each location. A switch in the dominant sediment source between the headwaters and the outlet of the watershed is observed. Sediment is enriched with shale bedrock and depleted of topsoil sources as the stream crosses and down-cuts through the Manitoba Escarpment. The switch in sources highlights the importance of the sampling location in relation to the scale and geomorphic connectivity of the watershed. Although the results include considerable uncertainty, they are consistent with the findings from a classical fingerprinting approach undertaken in the same watershed (i.e., geochemical and radionuclide fingerprints), and confirm the potential of sediment colour parameters as suitable fingerprints.

Relationship between consumer ranking of lamb colour and objective measures of colour.

PubMed

Khliji, S; van de Ven, R; Lamb, T A; Lanza, M; Hopkins, D L

2010-06-01

Given the lack of data that relates consumer acceptance of lamb colour to instrument measures a study was undertaken to establish the acceptability thresholds for fresh and displayed meat. Consumers (n=541) were asked to score 20 samples of lamb loin (m.longissimus thoracis et lumborum; LL) on an ordinal scale of 1 (very acceptable) to 5 (very unacceptable). A sample was considered acceptable by a consumer if it scored three or less. Ten samples were used for testing consumer response to fresh colour and 10 to test consumer response to colour during display of up to 4days. The colour of fresh meat was measured using a Minolta chromameter with a closed cone and a Hunter Lab Miniscan was used for measuring meat on display. For fresh meat when the a( *) (redness) and L( *) (lightness) values are equal to or exceed 9.5 and 34, respectively, on average consumers will consider the meat colour acceptable. However a( *) and L( *) values must be much higher (14.5 and 44, respectively) to have 95% confidence that a randomly selected consumer will consider a sample acceptable. For aged meat, when the wavelength ratio (630/580nm) and the a( *) values are equal to or greater than 3.3 and 14.8, respectively, on average consumers will consider the meat acceptable. These thresholds need to be increased to 6.8 for ratio (630/580nm) and 21.7 for a( *) to be 95% confident that a randomly selected consumer will consider a sample acceptable. Crown Copyright 2010. Published by Elsevier Ltd. All rights reserved.

Effects on colour characteristics of buffalo meat during blooming, retail display and using vitamin C during refrigerated storage.

PubMed

Sen, A R; Muthukumar, M; Naveena, B M; Ramanna, D B V

2014-11-01

Experiments were conducted to determine the effect of blooming, retail display and vitamin C on colour changes/improvement of buffalo meat. To evaluate the effect of blooming, top round cuts of buffalo were allowed to bloom for 60 min. As colour bloomed, a* value increased from 6.47 to 10.01 at 45 min; no further changes occurred. In another study, top round cuts were kept at ambient temperature (36 ± 2 °C) and evaluated for instrumental colour during display. The instrumental redness value (a*) and chroma significantly increased (P < 0.05) after 12 h of display. During storage at refrigerated temperature, treatments consisted of injecting muscle section with 5 % by weight of 0.5, 1 and 2 % vitamin C solutions and a non-injected control (0 %). Each part was evaluated for instrumental colour changes and sensory traits (colour and discoloration score) at 0, 3, 6 and 9th day of refrigerated storage. The a* value (redness) increased significantly in all vitamin C treated buffalo meat samples as compared to control stored at 4 °C. The chroma was significantly higher (P < 0.05) in treated meat as compared to control. Buffalo meat containing vitamin C maintained the desired red meat colour throughout the storage period. The buffalo muscle treated with 2 % vitamin C was more effective in preventing discoloration than treated with 0.5 and 1 % vitamin C. In our study it is evident that as colour bloomed, a* value (redness) increased which indicated that buffalo muscles became redder immediately after exposure to air during blooming and retail display. Vitamin C at levels between 0.5 and 2 % will minimize the rapid discoloration that occurs at the muscle surface. However, 2 % concentration of vitamin C was more effective in minimizing the discoloration and improving colour stability.

Comparative study of qualitative and quantitative methods to determine toxicity level of Aspergillus flavus isolates in maize.

PubMed

Shekhar, Meena; Singh, Nirupma; Dutta, Ram; Kumar, Shrvan; Mahajan, Vinay

2017-01-01

An attempt was made to compare between easy and inexpensive qualitative method (ammonia vapour test) and analytical methods (thin layer chromatography and enzyme-linked immunosorbent assay) for identification of aflatoxigenic isolates of Aspergillus flavus in maize. In this comparative study the toxicity level of A. flavus isolates exhibited 100% agreement among ammonia vapour test, ELISA and TLC for highly toxigenic (>2000 ppb) and toxigenic (501-2000 ppb) isolates while 88.5% agreement observed for least toxic (<20 ppb) isolates. In ammonia vapour test 51% of A. flavus isolates showed creamish or no colour change corresponding to least toxic/atoxic (<20ppb) category estimated by ELISA. Similarly 22% highly toxic isolates exhibited plum red colour, 12% moderately toxic indicated pink colour and 10% toxic isolates showed red colour. However, 11.5% isolates were found to be false positive in cream colour category (least toxic) and 28.5% false negatives in pink colour (moderately toxic) category. The isolates from different agroclimatic zones of maize in India showed high variability for aflatoxin B1 (AFB1) production potential ranging from 0.214-8116.61 ppb. Toxigenic potential of Aspergillus flavus isolates in culture was further validated by inoculating maize grain sample with four different isolates with varied toxin producing ability. With good agreement percentage between cultural and analytical methods the study concludes the ammonia vapour test to be easy, inexpensive, reliable and time saving method that can be used for segregating or pre-screening of contaminated samples from bulk food/feed stock.

New model for colour kinetics of plum under infrared vacuum condition and microwave drying.

PubMed

Chayjan, Reza Amiri; Alaei, Behnam

2016-01-01

Quality of dried foods is affected by the drying method and physiochemical changes in tissue. The drying method affects properties such as colour. The colour of processed food is one of the most important quality indices and plays a determinant role in consumer acceptability of food materials and the processing method. The colour of food materials can be used as an indirect factor to determine changes in quality, since it is simpler and faster than chemical methods. The study focused on the kinetics of colour changes of plum slices, under infrared vacuum and microwave conditions. Drying the samples was implemented at the absolute pressures of 20 and 60 kPa, drying temperatures of 50 and 60°C and microwave power of 90, 270, 450 and 630 W. Colour changes were quantified by the tri-stimulus L* (whiteness/darkness), a* (redness/greenness) and b* (yellowness/blueness) model, which is an international standard for color measurement developed by the Commission Internationale d'Eclairage (CIE). These values were also used to calculate total colour change (∆E), chroma, hue angle, and browning index (BI). A new model was used for mathematical modelling of colour change kinetics. The drying process changed the colour parameters of L*, a*, and b*, causing a colour shift toward the darker region. The values of L* and hue angle decreased, whereas the values of a*, b*, ∆E, chroma and browning index increased during exposure to infrared vacuum conditions and microwave drying. Comparing the results obtained using the new model with two conventional models of zero-order and first-order kinetics indicated that the new model presented more compatibility with the data of colour kinetics for all colour parameters and drying conditions. All kinetic changes in colour parameters can be explained by the new model presented in this study. The hybrid drying system included infrared vacuum conditions and microwave power for initial slow drying of plum slices and provided the desired results for colour change.

[Investigation of Color Vision Using Pigment Color Plates and a Tablet PC].

PubMed

Tsimpri, P; Kuchenbecker, J

2016-07-01

Many applications (apps) for ophthalmic solutions, including colour vision tests, are currently available. However, no colour vision test app has been evaluated through clinical trials on a tablet PC. Using standard test conditions and a tablet pc (iPad2®), colour vision tests were performed with 19 Velhagen/Broschmann/Kuchenbecker colour plates and an HMC anomaloscope. The plates were alternately presented at first in a book (pigment colour plates) and then in a tablet PC (iPad®). A total of 77 volunteer subjects were examined. 62 subjects were colour normal and 15 male subjects had a colour vision deficiency. The coincidence and the 95 % confidence intervals were determined. The average age of all subjects (n = 77) was 42.8 ± 16.9 years. The mean near visual acuity of all subjects was 0.99 ± 0.15. The coincidence of the results of all subjects between books and tablet PC was 88.0 %. The 95 % confidence interval ranged from 81.6 to 89.6 %. In the group of subjects with colour vision deficiency (n = 15), the coincidence was 83.3 %. The 95 % confidence interval ranged from 78.4 to 87.3 %. In the group of subjects without colour vision deficiency (n = 62), the coincidence was 89.1 %. The 95 % confidence interval ranged from 87.1 to 90.8 %. The overlap of error numbers of colour normal subjects and colour vision deficiency subjects was 2 errors with the book and 5 errors with the tablet pc. Testing colour vision using book and tablet pc only gives roughly comparable results. However, separation with the book was better and the colour plates differed in validity. For this reason, only some of the colour plates could be used on a tablet PC. Georg Thieme Verlag KG Stuttgart · New York.

Drawing ability in typical and atypical development; colour cues and the effect of oblique lines.

PubMed

Farran, E K; Dodd, G F

2015-06-01

Individuals with Williams syndrome (WS) have poor drawing ability. Here, we investigated whether colour could be used as a facilitation cue during a drawing task. Participants with WS and non-verbal ability matched typically developing (TD) children were shown line figures presented on a 3 by 3 dot matrix, and asked to replicate the figures by drawing on an empty dot matrix. The dots of the matrix were either all black (control condition), or nine different coloured dots (colour condition). In a third condition, which also used coloured dots, participants were additionally asked to verbalise the colours of the dots prior to replicating the line drawings (colour-verbal condition). Performance was stronger in both WS and TD groups on the two coloured conditions, compared with the control condition. However, the facilitation effect of colour was significantly weaker in the WS group than in the TD group. Replication of oblique line segments was less successful than replication of non-oblique line segments for both groups; this effect was reduced by colour facilitation in the TD group only. Verbalising the colours had no additional impact on performance in either group. We suggest that colour acted as a cue to individuate the dots, thus enabling participants to better ascertain the spatial relationships between the parts of each figure, to determine the start and end points of component lines, and to determine the correspondence between the model and their replication. The reduced facilitation in the WS group is discussed in relation to the effect of oblique versus non-oblique lines, the use of atypical drawing strategies, and reduced attention to the model when drawing the replication. © 2014 MENCAP and International Association of the Scientific Study of Intellectual and Developmental Disabilities and John Wiley & Sons Ltd.

Correlation of natural tooth colour with aging in the Spanish population.

PubMed

Gómez Polo, Cristina; Gómez Polo, Miguel; Montero, Javier; Martínez Vazquez De Parga, Juan Antonio; Celemin Viñuela, Alicia

2015-10-01

To analyse natural tooth colour in the Spanish population according to the colour coordinates lightness (L*), chroma (C*), hue (h*), red-green axis (a*) and yellow-blue axis (b*) in order to quantify the correlation and changes of tooth colour with age and sex. Natural tooth colour was measured in a sample of 1,361 Spanish participants of both sexes distributed within an age range of 16 to 89 years. The Easyshade Compact spectrophotometer was used and the CIELAB and CIELCh systems were followed. Pearson's bivariate correlations between age and colour coordinates were highly significant for L* (r=-0.674, P≤0.001), h* (r=-0.468, P≤0.001) and C* (r=0.417, P≤0.001). The correlation between age and colour coordinates was stronger for men than for women, for all colour coordinates. The results showed that C*, b* and a* increased by 0.60, 0.56 and 0.26 units/year on average, respectively, whereas L* and h* decreased progressively with age (by 0.60 units/year, on average), and colour differences increased in a systematic way as the gap between the ages being compared grew wider. The strongest correlation was found between age and L*, then between age and h* (both inverse relationships) and then between age and a*, C* and b* (direct relationships). In addition, a similar degree of change in the colour coordinates L*, C* and h* (of 0.60 units/year on average) was observed for natural tooth colour. Knowledge of the chromatic range of natural teeth may help to choose colour for the replacement of missing elements. © 2015 FDI World Dental Federation.

Colour measurement of colostrum for estimation of colostral IgG and colostrum composition in dairy cows.

PubMed

Gross, Josef J; Kessler, Evelyne C; Bruckmaier, Rupert M

2014-11-01

Instruments for on-farm determination of colostrum quality such as refractometers and densimeters are increasingly used in dairy farms. The colour of colostrum is also supposed to reflect its quality. A paler or mature milk-like colour is associated with a lower colostrum value in terms of its general composition compared with a more yellowish and darker colour. The objective of this study was to investigate the relationships between colour measurement of colostrum using the CIELAB colour space (CIE L*=from white to black, a*=from red to green, b*=from yellow to blue, chroma value G=visual perceived colourfulness) and its composition. Dairy cow colostrum samples (n=117) obtained at 4·7±1·5 h after parturition were analysed for immunoglobulin G (IgG) by ELISA and for fat, protein and lactose by infrared spectroscopy. For colour measurements, a calibrated spectrophotometer was used. At a cut-off value of 50 mg IgG/ml, colour measurement had a sensitivity of 50·0%, a specificity of 49·5%, and a negative predictive value of 87·9%. Colostral IgG concentration was not correlated with the chroma value G, but with relative lightness L*. While milk fat content showed a relationship to the parameters L*, a*, b* and G from the colour measurement, milk protein content was not correlated with a*, but with L*, b*, and G. Lactose concentration in colostrum showed only a relationship with b* and G. In conclusion, parameters of the colour measurement showed clear relationships to colostral IgG, fat, protein and lactose concentration in dairy cows. Implementation of colour measuring devices in automatic milking systems and milking parlours might be a potential instrument to access colostrum quality as well as detecting abnormal milk.

A comparison of hair colour measurement by digital image analysis with reflective spectrophotometry.

PubMed

Vaughn, Michelle R; van Oorschot, Roland A H; Baindur-Hudson, Swati

2009-01-10

While reflective spectrophotometry is an established method for measuring macroscopic hair colour, it can be cumbersome to use on a large number of individuals and not all reflective spectrophotometry instruments are easily portable. This study investigates the use of digital photographs to measure hair colour and compares its use to reflective spectrophotometry. An understanding of the accuracy of colour determination by these methods is of relevance when undertaking specific investigations, such as those on the genetics of hair colour. Measurements of hair colour may also be of assistance in cases where a photograph is the only evidence of hair colour available (e.g. surveillance). Using the CIE L(*)a(*)b(*) colour space, the hair colour of 134 individuals of European ancestry was measured by both reflective spectrophotometry and by digital image analysis (in V++). A moderate correlation was found along all three colour axes, with Pearson correlation coefficients of 0.625, 0.593 and 0.513 for L(*), a(*) and b(*) respectively (p-values=0.000), with means being significantly overestimated by digital image analysis for all three colour components (by an average of 33.42, 3.38 and 8.00 for L(*), a(*) and b(*) respectively). When using digital image data to group individuals into clusters previously determined by reflective spectrophotometric analysis using a discriminant analysis, individuals were classified into the correct clusters 85.8% of the time when there were two clusters. The percentage of cases correctly classified decreases as the number of clusters increases. It is concluded that, although more convenient, hair colour measurement from digital images has limited use in situations requiring accurate and consistent measurements.

Development and validation of a questionnaire assessing the quality of life impact of Colour Blindness (CBQoL).

PubMed

Barry, John A; Mollan, Susan; Burdon, Michael A; Jenkins, Michelle; Denniston, Alastair K

2017-10-02

Congenital colour vision deficiency (CVD), commonly called 'colour blindness', affects around 8% of men and 0.4% of women. Although many aspects of health (e.g. change in colour of urine) and healthcare (e.g. coloured medication, colour-coded diagnostic tests), and modern life depend upon colour coding (e.g. graphs, maps, signals), the impact of colour blindness on everyday life is not generally considered a topic of importance. This study is the first to create and validate a questionnaire measuring the quality of life (QoL) impact of being colour blind. This study consisted of two phases. Firstly, the questionnaire design and development phase was led by an expert panel and piloted on a focus group. Secondly, an online sample of 128 men and 291 women filled in the questionnaire, and the psychometric properties of the questionnaire were analysed using principal components analysis (PCA). The scores of colour blind (CB) participants and normal-sighted controls, controlling for age and sex, were compared using matched t-tests. The PCA resulted in a questionnaire with three domains (or subscales): QoL for Health & Lifestyle, QoL for Work, and QoL for Emotions. Controlling for age, there was a significantly greater negative impact on QoL for CB people than normal-sighted controls in regards to confusion over colour in various aspects of their health (p = 5 × 10 -7 ), work (p = 1.3 × 10 -7 ), and emotional life (p = 6 × 10 -5 ). Colour blindness can significantly impact quality of life for health, emotions, and especially careers. The tool developed here could be useful in future clinical studies to measure changes in CBQoL in response to therapy in conditions where colour vision is affected. We also discuss ways in which everyday problems related to colour vision might be reduced, for example, workplaces could avoid colour coding where a non-colour alternative is possible.

Why is the moon white?

PubMed

Sivaprasad, Sobha; Saleh, George M

2005-12-01

Land's Retinex theory is used to explain why we perceive the colour of the moon as white. The lightness values of coloured areas are computed and the energy at the particular area (moon) is compared with the surrounding area (space-vacuum).

Characterization of Streptomyces isolates causing colour changes of mural paintings in ancient Egyptian tombs.

PubMed

Abdel-Haliem, M E F; Sakr, A A; Ali, M F; Ghaly, M F; Sohlenkamp, C

2013-08-25

Paintings in ancient Egyptian tombs often suffer colour changes due to microbial growth and colonization. Streptomyces strains were isolated from mural paintings of Tell Basta and Tanis tombs (East of Nile Delta, Egypt) and were identified using biochemical and molecular methods. The16S rDNA sequences data indicated that isolated strains were closely related to S. coelicolor, S. albidofuscus, S. ambofaciens, S. canarius, S. parvullus, S. corchorusii, S. albidofuscus and S. nigrifaciens. It could be shown that Streptomyces strains are involved on a large scale in the colour changes of paintings and stone support by producing a wide range of metabolites such as acids (oxalic, citric and sulphuric acids), biopigments of melanin, carotenoids, and hydrogen sulphide. Copyright © 2013 Elsevier GmbH. All rights reserved.

Intellectual Estimates of Hearing-Impaired Children: A Comparison of Three Measures

ERIC Educational Resources Information Center

Ritter, David R.

1976-01-01

The Arthur Adaptation of the Leiter International Performance Scale, Raven's Coloured Progressive Matrices, and Wechsler Intelligence Scale for Children-Performance Section were administered to 31 children with mild to moderate hearing impairments. A comparison of test results indicated moderate convergent validity among the measures. (Author)

Spatio-temporal colour correction of strongly degraded movies

NASA Astrophysics Data System (ADS)

Islam, A. B. M. Tariqul; Farup, Ivar

2011-01-01

The archives of motion pictures represent an important part of precious cultural heritage. Unfortunately, these cinematography collections are vulnerable to different distortions such as colour fading which is beyond the capability of photochemical restoration process. Spatial colour algorithms-Retinex and ACE provide helpful tool in restoring strongly degraded colour films but, there are some challenges associated with these algorithms. We present an automatic colour correction technique for digital colour restoration of strongly degraded movie material. The method is based upon the existing STRESS algorithm. In order to cope with the problem of highly correlated colour channels, we implemented a preprocessing step in which saturation enhancement is performed in a PCA space. Spatial colour algorithms tend to emphasize all details in the images, including dust and scratches. Surprisingly, we found that the presence of these defects does not affect the behaviour of the colour correction algorithm. Although the STRESS algorithm is already in itself more efficient than traditional spatial colour algorithms, it is still computationally expensive. To speed it up further, we went beyond the spatial domain of the frames and extended the algorithm to the temporal domain. This way, we were able to achieve an 80 percent reduction of the computational time compared to processing every single frame individually. We performed two user experiments and found that the visual quality of the resulting frames was significantly better than with existing methods. Thus, our method outperforms the existing ones in terms of both visual quality and computational efficiency.

Learned perceptual associations influence visuomotor programming under limited conditions: kinematic consistency.

PubMed

Haffenden, Angela M; Goodale, Melvyn A

2002-12-01

Previous findings have suggested that visuomotor programming can make use of learned size information in experimental paradigms where movement kinematics are quite consistent from trial to trial. The present experiment was designed to test whether or not this conclusion could be generalized to a different manipulation of kinematic variability. As in previous work, an association was established between the size and colour of square blocks (e.g. red = large; yellow = small, or vice versa). Associating size and colour in this fashion has been shown to reliably alter the perceived size of two test blocks halfway in size between the large and small blocks: estimations of the test block matched in colour to the group of large blocks are smaller than estimations of the test block matched to the group of small blocks. Subjects grasped the blocks, and on other trials estimated the size of the blocks. These changes in perceived block size were incorporated into grip scaling only when movement kinematics were highly consistent from trial to trial; that is, when the blocks were presented in the same location on each trial. When the blocks were presented in different locations grip scaling remained true to the metrics of the test blocks despite the changes in perceptual estimates of block size. These results support previous findings suggesting that kinematic consistency facilitates the incorporation of learned perceptual information into grip scaling.

The influence of the microscope lamp filament colour temperature on the process of digital images of histological slides acquisition standardization.

PubMed

Korzynska, Anna; Roszkowiak, Lukasz; Pijanowska, Dorota; Kozlowski, Wojciech; Markiewicz, Tomasz

2014-01-01

The aim of this study is to compare the digital images of the tissue biopsy captured with optical microscope using bright field technique under various light conditions. The range of colour's variation in immunohistochemically stained with 3,3'-Diaminobenzidine and Haematoxylin tissue samples is immense and coming from various sources. One of them is inadequate setting of camera's white balance to microscope's light colour temperature. Although this type of error can be easily handled during the stage of image acquisition, it can be eliminated with use of colour adjustment algorithms. The examination of the dependence of colour variation from microscope's light temperature and settings of the camera is done as an introductory research to the process of automatic colour standardization. Six fields of view with empty space among the tissue samples have been selected for analysis. Each field of view has been acquired 225 times with various microscope light temperature and camera white balance settings. The fourteen randomly chosen images have been corrected and compared, with the reference image, by the following methods: Mean Square Error, Structural SIMilarity and visual assessment of viewer. For two types of backgrounds and two types of objects, the statistical image descriptors: range, median, mean and its standard deviation of chromaticity on a and b channels from CIELab colour space, and luminance L, and local colour variability for objects' specific area have been calculated. The results have been averaged for 6 images acquired in the same light conditions and camera settings for each sample. The analysis of the results leads to the following conclusions: (1) the images collected with white balance setting adjusted to light colour temperature clusters in certain area of chromatic space, (2) the process of white balance correction for images collected with white balance camera settings not matched to the light temperature moves image descriptors into proper chromatic space but simultaneously the value of luminance changes. So the process of the image unification in a sense of colour fidelity can be solved in separate introductory stage before the automatic image analysis.

SPIDER - I. Sample and galaxy parameters in the grizYJHK wavebands

NASA Astrophysics Data System (ADS)

La Barbera, F.; de Carvalho, R. R.; de La Rosa, I. G.; Lopes, P. A. A.; Kohl-Moreira, J. L.; Capelato, H. V.

2010-11-01

This is the first paper of a series presenting the Spheroids Panchromatic Investigation in Different Environmental Regions (SPIDER). The sample of spheroids consists of 5080 bright (Mr < -20) early-type galaxies (ETGs), in the redshift range of 0.05 to 0.095, with optical (griz) photometry and spectroscopy from the Sloan Digital Sky Survey Data Release 6 (SDSS-DR6) and near-infrared (YJHK) photometry from the UKIRT Infrared Deep Sky Survey-Large Area Survey (UKIDSS-LAS) (DR4). We describe how homogeneous photometric parameters (galaxy colours and structural parameters) are derived using grizYJHK wavebands. We find no systematic steepening of the colour-magnitude relation when probing the baseline from g - r to g - K, implying that internal colour gradients drive most of the mass-metallicity relation in ETGs. As far as structural parameters are concerned we find that the mean effective radius of ETGs smoothly decreases, by 30 per cent, from g through K, while no significant dependence on waveband is detected for the axial ratio, Sersic index and a4 parameters. Furthermore, velocity dispersions are remeasured for all the ETGs using STARLIGHT and compared to those obtained by SDSS. The velocity dispersions are rederived using a combination of simple stellar population models as templates, hence accounting for the kinematics of different galaxy stellar components. We compare our (2DPHOT) measurements of total magnitude, effective radius and mean surface brightness with those obtained as part of the SDSS pipeline (PHOTO). Significant differences are found and reported, including comparisons with a third and independent part. A full characterization of the sample completeness in all wavebands is presented, establishing the limits of application of the characteristic parameters presented here for the analysis of the global scaling relations of ETGs.

Home-based screening for biliary atresia using infant stool colour cards: a large-scale prospective cohort study and cost-effectiveness analysis.

PubMed

Schreiber, Richard A; Masucci, Lisa; Kaczorowski, Janusz; Collet, J P; Lutley, Pamela; Espinosa, Victor; Bryan, Stirling

2014-09-01

Biliary atresia (BA), a leading cause of paediatric liver failure and liver transplantation, manifests by three weeks of life as jaundice with acholic stools. Poor outcomes due to delayed diagnosis remain a problem worldwide. We evaluated and assessed the cost-effectiveness of methods of introducing a BA Infant Stool Colour Card (ISCC) screening programme in Canada. A prospective study at BC Women's Hospital recruited consecutive healthy newborns through six incrementally more intensive screening approaches. Under the baseline "passive" strategy, families received ISCCs at maternity, with instructions to monitor infant stool colour daily and return the ISCC by mail at age 30 days. Additional strategies were: ISCC mailed to family physician; reminder letters or telephone calls to families or physicians. Random telephone surveys of ISCC non-returners assessed total card utilization. Primary outcome was ISCC utilization rate expressed as a composite outcome of the ISCC return rate and non-returned ISCC use. Markov modelling was used to predict incremental costs and life years gained from screening (passive and reminder), compared with no screening, over a 10-year time horizon. 6,187 families were enrolled. Card utilization rates in the passive screening strategy were estimated at 60-94%. For a Canadian population, the increase in cost for passive screening, compared with no screening, is $213,584 and the gain in life years is 9.7 ($22,000 per life-year gained). A BA ISCC screening programme targeting families of newborns is feasible in Canada. Passive distribution of ISCC at maternity is potentially effective and highly cost-effective. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Galaxy Zoo: secular evolution of barred galaxies from structural decomposition of multiband images

NASA Astrophysics Data System (ADS)

Kruk, Sandor J.; Lintott, Chris J.; Bamford, Steven P.; Masters, Karen L.; Simmons, Brooke D.; Häußler, Boris; Cardamone, Carolin N.; Hart, Ross E.; Kelvin, Lee; Schawinski, Kevin; Smethurst, Rebecca J.; Vika, Marina

2018-02-01

We present the results of two-component (disc+bar) and three-component (disc+bar+bulge) multiwavelength 2D photometric decompositions of barred galaxies in five Sloan Digital Sky Survey (SDSS) bands (ugriz). This sample of ∼3500 nearby (z < 0.06) galaxies with strong bars selected from the Galaxy Zoo citizen science project is the largest sample of barred galaxies to be studied using photometric decompositions that include a bar component. With detailed structural analysis, we obtain physical quantities such as the bar- and bulge-to-total luminosity ratios, effective radii, Sérsic indices and colours of the individual components. We observe a clear difference in the colours of the components, the discs being bluer than the bars and bulges. An overwhelming fraction of bulge components have Sérsic indices consistent with being pseudo-bulges. By comparing the barred galaxies with a mass-matched and volume-limited sample of unbarred galaxies, we examine the connection between the presence of a large-scale galactic bar and the properties of discs and bulges. We find that the discs of unbarred galaxies are significantly bluer compared to the discs of barred galaxies, while there is no significant difference in the colours of the bulges. We find possible evidence of secular evolution via bars that leads to the build-up of pseudo-bulges and to the quenching of star formation in the discs. We identify a subsample of unbarred galaxies with an inner lens/oval and find that their properties are similar to barred galaxies, consistent with an evolutionary scenario in which bars dissolve into lenses. This scenario deserves further investigation through both theoretical and observational work.

Millennial-scale climate variations recorded in Early Pliocene colour reflectance time series from the lacustrine Ptolemais Basin (NW Greece)

NASA Astrophysics Data System (ADS)

Steenbrink, J.; Kloosterboer-van Hoeve, M. L.; Hilgen, F. J.

2003-03-01

Quaternary climate proxy records show compelling evidence for climate variability on time scales of a few thousand years. The causes for these millennial-scale or sub-Milankovitch cycles are still poorly understood, not least due to the complex feedback mechanisms of large ice sheets during the Quaternary. We present evidence of millennial-scale climate variability in Early Pliocene lacustrine sediments from the intramontane Ptolemais Basin in northwestern Greece. The sediments are well exposed in a series of open-pit lignite mines and exhibit a distinct millennial-scale sedimentary cyclicity of alternating lignites and lacustrine marl beds that resulted from precession-induced variations in climate. The higher-frequency, millennial-scale cyclicity is particularly prominent within the grey-coloured marl segment of individual cycles. A stratigraphic interval of ˜115 ka, covering five precession-induced sedimentary cycles, was studied in nine parallel sections from two open-pit lignite mines located several km apart. High-resolution colour reflectance records were used to quantify the within-cycle variability and to determine its lateral continuity. Much of the within-cycle variability could be correlated between the parallel sections, even in fine detail, which suggests that these changes reflect basin-wide variations in environmental conditions related to (regional) climate fluctuations. Interbedded volcanic ash beds demonstrate the synchronicity of these fluctuations and spectral analysis of the reflectance time series shows a significant concentration of within-cycle variability at periods of ˜11, ˜5.5 and ˜2 ka. The occurrence of variability at such time scales at times before the intensification of the Northern Hemisphere glaciation suggests that they cannot solely have resulted from internal ice-sheet dynamics. Possible candidates include harmonics or combination tones of the main orbital cycles, variations in solar output or periodic motions of the Earth and Moon.

Mapping of AFLP markers linked to seed coat colour loci in Brassica juncea (L.) Czern.

PubMed

Sabharwal, V; Negi, M S; Banga, S S; Lakshmikumaran, M

2004-06-01

Association mapping of the seed-coat colour with amplified fragment length polymorphism (AFLP) markers was carried out in 39 Brassica juncea lines. The lines had genetically diverse parentages and varied for seed-coat colour and other morphological characters. Eleven AFLP primer combinations were used to screen the 39 B. juncea lines, and a total of 335 polymorphic bands were detected. The bands were analysed for association with seed-coat colour using multiple regression analysis. This analysis revealed 15 markers associated with seed-coat colour, obtained with eight AFLP primer combinations. The marker E-ACA/M-CTG(350 )explained 69% of the variation in seed-coat colour. This marker along with markers E-AAC/M-CTC(235 )and E-AAC/M-CTA(250) explained 89% of the total variation. The 15 associated markers were validated for linkage with the seed-coat colour loci using a recombinant inbred line (RIL) mapping population. Bands were amplified with the eight AFLP primer combinations in 54 RIL progenies. Of the 15 associated markers, 11 mapped on two linkage groups. Eight markers were placed on linkage group 1 at a marker density of 6.0 cM, while the remaining three were mapped on linkage group 2 at a marker density of 3.6 cM. Marker E-ACA/M-CTG(350 )co-segregated with Gene1 controlling seed-coat colour; it was specific for yellow seed-coat colour and mapped to linkage group 1. Marker E-AAC/M-CTC(235) (AFLP8), which had been studied previously, was present on linkage group 2; it was specific for brown seed-coat colour. Since AFLP markers are not adapted for large-scale applications in plant breeding, it is important to convert these to sequence-characterised amplified region (SCAR) markers. Marker E-AAC/M-CTC(235) (AFLP8) had been previously converted into a SCAR. Work is in progress to convert the second of the linked markers, E-ACA/M-CTG(350), to a SCAR. The two linked AFLP markers converted to SCARs will be useful for developing yellow-seeded B. juncea lines by means of marker-assisted selection.

The effect of accelerated ageing on colour stability of visible light-cured (VLC) chairside denture liners.

PubMed

Kostoulas, Ioannis; Polyzois, Gregory; Mitsoudis, Anastasios; Kavoura, Victoria; Frangou, Maria

2012-06-01

The purpose of this study was to assess the colour stability of seven visible light-cured (VLC) hard and soft denture liners by an in vitro accelerated ageing test and compare them with two autopolymerised hard and soft liners. Ten specimens of each material were fabricated. The initial colour was measured with a tri-stimulus colorimeter. One set of five specimens was placed in distilled water at 37°C in the dark for 15 days, while the remaining were subjected to UV/visible light-accelerated ageing initially for 24 h and then for 144 h. Colour change (ΔΕ) was calculated. Data were statistically analysed by anova, Tukey and t-tests at α = 0.05. All the liners showed clinically acceptable colour change (ΔΕ ≤ 6.8) in distilled water. The colour changes after ageing for Triad DuaLine, Lightdon U, Ufi Gel H and Light Liner Hard were clinically unacceptable (ΔΕ ≥ 6.8), whereas LightLiner Soft, Astron LC Soft, Triad Resiline and Flexacryl Soft presented slighter and clinically acceptable colour change (ΔΕ ≤ 6.8). Accelerated ageing affected significantly the colour stability of all denture liners tested except Astron LC Soft. Soft VLC denture liners were more colour-stable than hard VLC liners. © 2011 The Gerodontology Society and John Wiley & Sons A/S.

The Colour Test for drug susceptibility testing of Mycobacterium tuberculosis strains.

PubMed

Toit, K; Mitchell, S; Balabanova, Y; Evans, C A; Kummik, T; Nikolayevskyy, V; Drobniewski, F

2012-08-01

Tartu, Estonia. To assess the performance and feasibility of the introduction of the thin-layer agar MDR/XDR-TB Colour Test (Colour Test) as a non-commercial method of drug susceptibility testing (DST). The Colour Test combines the thin-layer agar technique with a simple colour-coded quadrant format, selective medium to reduce contamination and colorimetric indication of bacterial growth to simplify interpretation. DST patterns for isoniazid (INH), rifampicin (RMP) and ciprofloxacin (CFX) were determined using the Colour Test for 201 archived Mycobacterium tuberculosis isolates. Susceptibilities were compared to blinded DST results obtained routinely using the BACTEC™ Mycobacteria Growth Indicator Tube™ (MGIT) 960 to assess performance characteristics. In all, 98% of the isolates produced interpretable results. The average time to positivity was 13 days, and all results were interpretable. The Colour Test detected drug resistance with 98% sensitivity for INH, RMP and CFX and 99% for multidrug-resistant tuberculosis. Specificities were respectively 100% (95%CI 82-100), 88% (95%CI 69-97) and 91% (95%CI 83-96) and 90% (95%CI 74-98). Agreement between the Colour Test and BACTEC MGIT 960 were respectively 98%, 96%, 94% and 97%. The Colour Test could be an economical, accurate and simple technique for testing tuberculosis strains for drug resistance. As it requires little specialist equipment, it may be particularly useful in resource-constrained settings with growing drug resistance rates.

Varieties of grapheme-colour synaesthesia: a new theory of phenomenological and behavioural differences.

PubMed

Ward, Jamie; Li, Ryan; Salih, Shireen; Sagiv, Noam

2007-12-01

Recent research has suggested that not all grapheme-colour synaesthetes are alike. One suggestion is that they can be divided, phenomenologically, in terms of whether the colours are experienced in external or internal space (projector-associator distinction). Another suggestion is that they can be divided according to whether it is the perceptual or conceptual attributes of a stimulus that is critical (higher-lower distinction). This study compares the behavioural performance of 7 projector and 7 associator synaesthetes. We demonstrate that this distinction does not map on to behavioural traits expected from the higher-lower distinction. We replicate previous research showing that projectors are faster at naming their synaesthetic colours than veridical colours, and that associators show the reverse profile. Synaesthetes who project colours into external space but not on to the surface of the grapheme behave like associators on this task. In a second task, graphemes presented briefly in the periphery are more likely to elicit reports of colour in projectors than associators, but the colours only tend to be accurate when the grapheme itself is also accurately identified. We propose an alternative model of individual differences in grapheme-colour synaesthesia that emphasises the role of different spatial reference frames in synaesthetic perception. In doing so, we attempt to bring the synaesthesia literature closer to current models of non-synaesthetic perception, attention and binding.

Mueller matrix microscopy on a Morpho butterfly

NASA Astrophysics Data System (ADS)

Arteaga, Oriol; Kuntman, Ertan; Antó, Joan; Pascual, Esther; Canillas, Adolf; Bertran, Enric

2015-04-01

The brilliant iridescent colouring in male Morpho butterflies is due to the microstrutures and nanostructures present in the wing scales, rather than pigments. In this work Mueller matrix microscopy is used to investigate the polarization properties of butterfly wing scales in reflection and transmission. It is found that the top layer of more transparent scales (cover scales) have very different polarimetric properties from the ground iridescent scales. Images with high spatial resolution showing the retarding and diattenuating optical properties for both types of scales are provided.

Screening for diabetic retinopathy using digital colour photography and oral fluorescein angiography.

PubMed

Newsom, R; Moate, B; Casswell, T

2000-08-01

To evaluate digital colour photography and oral fluorescein angiography (OFA) for diabetic retinopathy screening. Thirty-seven patients were selected from either a diabetic retinopathy screening or a medical retina clinic. Three 45 degrees colour digital images and a single macula 45 degrees OFA image were taken from each eye. Standard seven-field stereo photography with ETDRS grading was used as a gold standard for data comparison. The images were assessed by two graders and the results of each method compared using the McNemar test. Five eyes had no diabetic retinopathy, 50 had background diabetic retinopathy, 3 had pre-proliferative diabetic retinopathy, 11 had proliferative disease and 3 had quiescent posttreatment disease. Clinically significant macular oedema was present in 25 eyes and absent in 48. For grading diabetic retinopathy digital colour photography produced a sensitivity of 0.87 (specificity 0.83); OFA produced a sensitivity of 0.87 (specificity 0.80) (p = 0.1). For the detection of diabetic maculopathy, the sensitivity of digital colour photography was 0.48 (specificity of 0.95) and for OFA was 0.87 (specificity 0.87) (p < 0.01). This pilot study has shown that both digital colour photography and OFA compare well with conventional methods for diabetic retinopathy screening. The results encourage the further evaluation of OFA in the screening for diabetic maculopathy.

Facilitation of creative performance by using blue and red accent lighting in work and learning areas.

PubMed

Kombeiz, Olga; Steidle, Anna

2018-03-01

Research has shown that colours influence motivation and cognitive performance. In achievement contexts, red evokes avoidance motivation that hinders creativity, while blue elicits an approach motivation that facilitates creativity. However, due to their position and mode of presentation, colours may convey a different message. Red accent lighting creates a cosy, friendly room atmosphere that may, even in an achievement context, elicit an approach rather than an avoidance motivation. Results (N = 146) showed that both blue and red accent light increased strategic approach motivation compared to white accent light. Moreover, through the heightened approach motivation, colourful accent light indirectly improved creative performance. Implications for future research on colour and practical implications for colour usage are discussed. Practitioner Summary: Designing work environments for creativity is a new topic in ergonomics research and practice. The present study demonstrates indirect effects of coloured accent light on creativity providing interesting possibilities for the design of workplaces for knowledge workers, classrooms and all other rooms in which people work on new ideas.

Spectral response data for development of cool coloured tile coverings

NASA Astrophysics Data System (ADS)

Libbra, Antonio; Tarozzi, Luca; Muscio, Alberto; Corticelli, Mauro A.

2011-03-01

Most ancient or traditional buildings in Italy show steep-slope roofs covered by red clay tiles. As the rooms immediately below the roof are often inhabited in historical or densely urbanized centres, the combination of low solar reflectance of tile coverings and low thermal inertia of either wooden roof structures or sub-tile insulation panels makes summer overheating a major problem. The problem can be mitigated by using tiles coated with cool colours, that is colours with the same spectral response of clay tiles in the visible, but highly reflecting in the near infrared range, which includes more than half of solar radiation. Cool colours can yield the same visible aspect of common building surfaces, but higher solar reflectance. Studies aimed at developing cool colour tile coverings for traditional Italian buildings have been started. A few coating solutions with the typical red terracotta colour have been produced and tested in the laboratory, using easily available materials. The spectral response and the solar reflectance have been measured and compared with that of standard tiles.

Camouflage, communication and thermoregulation: lessons from colour changing organisms.

PubMed

Stuart-Fox, Devi; Moussalli, Adnan

2009-02-27

Organisms capable of rapid physiological colour change have become model taxa in the study of camouflage because they are able to respond dynamically to the changes in their visual environment. Here, we briefly review the ways in which studies of colour changing organisms have contributed to our understanding of camouflage and highlight some unique opportunities they present. First, from a proximate perspective, comparison of visual cues triggering camouflage responses and the visual perception mechanisms involved can provide insight into general visual processing rules. Second, colour changing animals can potentially tailor their camouflage response not only to different backgrounds but also to multiple predators with different visual capabilities. We present new data showing that such facultative crypsis may be widespread in at least one group, the dwarf chameleons. From an ultimate perspective, we argue that colour changing organisms are ideally suited to experimental and comparative studies of evolutionary interactions between the three primary functions of animal colour patterns: camouflage; communication; and thermoregulation.

Camouflage, communication and thermoregulation: lessons from colour changing organisms

PubMed Central

Stuart-Fox, Devi; Moussalli, Adnan

2008-01-01

Organisms capable of rapid physiological colour change have become model taxa in the study of camouflage because they are able to respond dynamically to the changes in their visual environment. Here, we briefly review the ways in which studies of colour changing organisms have contributed to our understanding of camouflage and highlight some unique opportunities they present. First, from a proximate perspective, comparison of visual cues triggering camouflage responses and the visual perception mechanisms involved can provide insight into general visual processing rules. Second, colour changing animals can potentially tailor their camouflage response not only to different backgrounds but also to multiple predators with different visual capabilities. We present new data showing that such facultative crypsis may be widespread in at least one group, the dwarf chameleons. From an ultimate perspective, we argue that colour changing organisms are ideally suited to experimental and comparative studies of evolutionary interactions between the three primary functions of animal colour patterns: camouflage; communication; and thermoregulation. PMID:19000973

Making better scientific figures

NASA Astrophysics Data System (ADS)

Hawkins, Ed; McNeall, Doug

2016-04-01

In the words of the UK government chief scientific adviser "Science is not finished until it's communicated" (Walport 2013). The tools to produce good visual communication have never been so easily accessible to scientists as at the present. Correspondingly, it has never been easier to produce and disseminate poor graphics. In this presentation, we highlight some good practice and offer some practical advice in preparing scientific figures for presentation to peers or to the public. We identify common mistakes in visualisation, including some made by the authors, and offer some good reasons not to trust defaults in graphics software. In particular, we discuss the use of colour scales and share our experiences in running a social media campaign (http://tiny.cc/endrainbow) to replace the "rainbow" (also "jet", or "spectral") colour scale as the default in (climate) scientific visualisation.

The adaptive significance of sensory bias in a foraging context: floral colour preferences in the bumblebee Bombus terrestris.

PubMed

Raine, Nigel E; Chittka, Lars

2007-06-20

Innate sensory biases could play an important role in helping naïve animals to find food. As inexperienced bees are known to have strong innate colour biases we investigated whether bumblebee (Bombus terrestris) colonies with stronger biases for the most rewarding flower colour (violet) foraged more successfully in their local flora. To test the adaptive significance of variation in innate colour bias, we compared the performance of colour-naïve bees, from nine bumblebee colonies raised from local wild-caught queens, in a laboratory colour bias paradigm using violet (bee UV-blue) and blue (bee blue) artificial flowers. The foraging performance of the same colonies was assessed under field conditions. Colonies with a stronger innate bias for violet over blue flowers in the laboratory harvested more nectar per unit time under field conditions. In fact, the colony with the strongest bias for violet (over blue) brought in 41% more nectar than the colony with the least strong bias. As violet flowers in the local area produce more nectar than blue flowers (the next most rewarding flower colour), these data are consistent with the hypothesis that local variation in flower traits could drive selection for innate colour biases.

The Adaptive Significance of Sensory Bias in a Foraging Context: Floral Colour Preferences in the Bumblebee Bombus terrestris

PubMed Central

Raine, Nigel E.; Chittka, Lars

2007-01-01

Innate sensory biases could play an important role in helping naïve animals to find food. As inexperienced bees are known to have strong innate colour biases we investigated whether bumblebee (Bombus terrestris) colonies with stronger biases for the most rewarding flower colour (violet) foraged more successfully in their local flora. To test the adaptive significance of variation in innate colour bias, we compared the performance of colour-naïve bees, from nine bumblebee colonies raised from local wild-caught queens, in a laboratory colour bias paradigm using violet (bee UV-blue) and blue (bee blue) artificial flowers. The foraging performance of the same colonies was assessed under field conditions. Colonies with a stronger innate bias for violet over blue flowers in the laboratory harvested more nectar per unit time under field conditions. In fact, the colony with the strongest bias for violet (over blue) brought in 41% more nectar than the colony with the least strong bias. As violet flowers in the local area produce more nectar than blue flowers (the next most rewarding flower colour), these data are consistent with the hypothesis that local variation in flower traits could drive selection for innate colour biases. PMID:17579727

The use of GIS and multi-criteria evaluation (MCE) to identify agricultural land management practices which cause surface water pollution in drinking water supply catchments.

PubMed

Grayson, Richard; Kay, Paul; Foulger, Miles

2008-01-01

Diffuse pollution poses a threat to water quality and results in the need for treatment for potable water supplies which can prove costly. Within the Yorkshire region, UK, nitrates, pesticides and water colour present particular treatment problems. Catchment management techniques offer an alternative to 'end of pipe' solutions and allow resources to be targeted to the most polluting areas. This project has attempted to identify such areas using GIS based modelling approaches in catchments where water quality data were available. As no model exists to predict water colour a model was created using an MCE method which is capable of predicting colour concentrations at the catchment scale. CatchIS was used to predict pesticide and nitrate N concentrations and was found to be generally capable of reliably predicting nitrate N loads at the catchment scale. The pesticides results did not match the historic data possibly due to problems with the historic pesticide data and temporal and spatially variability in pesticide usage. The use of these models can be extended to predict water quality problems in catchments where water quality data are unavailable and highlight areas of concern. IWA Publishing 2008.

Colour compatibility between teeth and dental shade guides in Quinquagenarians and Septuagenarians.

PubMed

Cocking, C; Cevirgen, E; Helling, S; Oswald, M; Corcodel, N; Rammelsberg, P; Reinelt, G; Hassel, A J

2009-11-01

The aim of this investigation was to determine colour compatibility between dental shade guides, namely, VITA Classical (VC) and VITA 3D-Master (3D), and human teeth in quinquagenarians and septuagenarians. Tooth colour, described in terms of L*a*b* values of the middle third of facial tooth surface of 1391 teeth, was measured using VITA Easyshade in 195 subjects (48% female). These were compared with the colours (L*a*b* values) of the shade tabs of VC and 3D. The mean coverage error and the percentage of tooth colours being within a given colour difference (DeltaE(ab)) from the tabs of VC and 3D were calculated. For comparison, hypothetical, optimized, population-specific shade guides were additionally calculated based on discrete optimization techniques for optimizing coverage. Mean coverage error was DeltaE(ab) = 3.51 for VC and DeltaE(ab) = 2.96 for 3D. Coverage of tooth colours by the tabs of VC and 3D within DeltaE(ab) = 2 was 23% and 24%, respectively, (DeltaE(ab)

European dental students' opinions about visual and digital tooth colour determination systems.

PubMed

Dozic, Alma; Kharbanda, Aron K; Kamell, Hassib; Brand, Henk S

2011-12-01

The aim of the study was to investigate students' opinion about visual and digital tooth colour determination education at different European dental schools. A cross-sectional web-based survey was created, containing nine dichotomous, multiple choice and 5-point Likert scale questions. The questionnaire was distributed amongst students of 40 European dental schools. Seven hundred and ninety-nine completed questionnaires from students of 15 dental schools were analysed statistically. Vitapan Classical and Vitapan 3D-Master are the most frequently used visual determination systems at European dental schools. Most students responded with "neutral" regarding whether they find it easy to identify the colour of teeth with a visual determination system (range 2.8-3.6). A minority of the dental students had received education in digital imaging systems (2-47%). The Easyshade was the most frequently mentioned digital system. The majority of the students who did not receive education on digital systems would like to see this topic added to the curriculum (77-100%). The dental students who had worked with both methods found it significantly easier to determine tooth colour with a digital system than with a visual system (mean score 3.5 ± 0.8 vs. 3.0 ± 0.8). Tooth colour determination programmes show a considerable variation across European dental schools. Based upon the outcomes of this study, students prefer digital imaging systems over visual systems, and like to have (more) education about digital tooth colour imaging. Copyright © 2011 Elsevier Ltd. All rights reserved.

Bleed-through correction for rendering and correlation analysis in multi-colour localization microscopy

PubMed Central

Kim, Dahan; Curthoys, Nikki M.; Parent, Matthew T.; Hess, Samuel T.

2015-01-01

Multi-colour localization microscopy has enabled sub-diffraction studies of colocalization between multiple biological species and quantification of their correlation at length scales previously inaccessible with conventional fluorescence microscopy. However, bleed-through, or misidentification of probe species, creates false colocalization and artificially increases certain types of correlation between two imaged species, affecting the reliability of information provided by colocalization and quantified correlation. Despite the potential risk of these artefacts of bleed-through, neither the effect of bleed-through on correlation nor methods of its correction in correlation analyses has been systematically studied at typical rates of bleed-through reported to affect multi-colour imaging. Here, we present a reliable method of bleed-through correction applicable to image rendering and correlation analysis of multi-colour localization microscopy. Application of our bleed-through correction shows our method accurately corrects the artificial increase in both types of correlations studied (Pearson coefficient and pair correlation), at all rates of bleed-through tested, in all types of correlations examined. In particular, anti-correlation could not be quantified without our bleed-through correction, even at rates of bleed-through as low as 2%. Demonstrated with dichroic-based multi-colour FPALM here, our presented method of bleed-through correction can be applied to all types of localization microscopy (PALM, STORM, dSTORM, GSDIM, etc.), including both simultaneous and sequential multi-colour modalities, provided the rate of bleed-through can be reliably determined. PMID:26185614

Bleed-through correction for rendering and correlation analysis in multi-colour localization microscopy.

PubMed

Kim, Dahan; Curthoys, Nikki M; Parent, Matthew T; Hess, Samuel T

2013-09-01

Multi-colour localization microscopy has enabled sub-diffraction studies of colocalization between multiple biological species and quantification of their correlation at length scales previously inaccessible with conventional fluorescence microscopy. However, bleed-through, or misidentification of probe species, creates false colocalization and artificially increases certain types of correlation between two imaged species, affecting the reliability of information provided by colocalization and quantified correlation. Despite the potential risk of these artefacts of bleed-through, neither the effect of bleed-through on correlation nor methods of its correction in correlation analyses has been systematically studied at typical rates of bleed-through reported to affect multi-colour imaging. Here, we present a reliable method of bleed-through correction applicable to image rendering and correlation analysis of multi-colour localization microscopy. Application of our bleed-through correction shows our method accurately corrects the artificial increase in both types of correlations studied (Pearson coefficient and pair correlation), at all rates of bleed-through tested, in all types of correlations examined. In particular, anti-correlation could not be quantified without our bleed-through correction, even at rates of bleed-through as low as 2%. Demonstrated with dichroic-based multi-colour FPALM here, our presented method of bleed-through correction can be applied to all types of localization microscopy (PALM, STORM, dSTORM, GSDIM, etc.), including both simultaneous and sequential multi-colour modalities, provided the rate of bleed-through can be reliably determined.

On the colour of wing scales in butterflies: iridescence and preferred orientation of single gyroid photonic crystals.

PubMed

Corkery, Robert W; Tyrode, Eric C

2017-08-06

Lycaenid butterflies from the genera Callophrys , Cyanophrys and Thecla have evolved remarkable biophotonic gyroid nanostructures within their wing scales that have only recently been replicated by nanoscale additive manufacturing. These nanostructures selectively reflect parts of the visible spectrum to give their characteristic non-iridescent, matte-green appearance, despite a distinct blue-green-yellow iridescence predicted for individual crystals from theory. It has been hypothesized that the organism must achieve its uniform appearance by growing crystals with some restrictions on the possible distribution of orientations, yet preferential orientation observed in Callophrys rubi confirms that this distribution need not be uniform. By analysing scanning electron microscope and optical images of 912 crystals in three wing scales, we find no preference for their rotational alignment in the plane of the scales. However, crystal orientation normal to the scale was highly correlated to their colour at low (conical) angles of view and illumination. This correlation enabled the use of optical images, each containing up to 10 4 -10 5 crystals, for concluding the preferential alignment seen along the [Formula: see text] at the level of single scales, appears ubiquitous. By contrast, [Formula: see text] orientations were found to occur at no greater rate than that expected by chance. Above a critical cone angle, all crystals reflected bright green light indicating the dominant light scattering is due to the predicted band gap along the [Formula: see text] direction, independent of the domain orientation. Together with the natural variation in scale and wing shapes, we can readily understand the detailed mechanism of uniform colour production and iridescence suppression in these butterflies. It appears that the combination of preferential alignment normal to the wing scale, and uniform distribution within the plane is a near optimal solution for homogenizing the angular distribution of the [Formula: see text] band gap relative to the wings. Finally, the distributions of orientations, shapes, sizes and degree of order of crystals within single scales provide useful insights for understanding the mechanisms at play in the formation of these biophotonic nanostructures.

Gas discharge headlights and visibility of coloured road signs.

PubMed

Venkatachalam, Kannan; Smith, George

2000-01-01

BACKGROUND: Automotive headlamps mostly use the tungsten halogen bulb but several years ago a new type of headlamp, the gas discharge bulb, was introduced. Because of the different spectral output of this type of lamp, there has been a suggestion that it may affect the colour recognition and sign conspicuity under night-time conditions. In this study, the visibility of the road signs is used to examine the effect of the gas discharge lamp's spectrum compared with that of the conventional halogen headlamp. METHODS: The spectral output of the lamps and the spectral reflectance of common-coloured road signs were measured using a Spectra-Pritchard spectroradiometer. Using luminous reflectance data, chromaticity co-ordinates and the colorimetric shift of the road signs, when illuminated by gas discharge lamps, were plotted using CIE x,y co-ordinate system. Colour rendering indices of the lamp were calculated using Munsell samples and road signs as proscribed by the CIE Publication. In addition, the visibility index of the road signs was calculated using Adrian's 'Visibility of Target' model. RESULTS: The gas discharge headlamp has more energy in the blue region and less energy in the red region of the spectrum than the halogen headlamp. The general colour rendering index of the gas discharge lamp is higher than that of the halogen lamp. When compared with daylight, all coloured road signs used in this study have less colorimetric shift when illuminated by the gas discharge headlamp than by the halogen headlamp. CONCLUSION: The result indicates that the gas discharge lamp, while having a very different spectrum from daylight or tungsten halogen lamps, should not have a deleterious effect on sign detection or recognition, when compared to daylight or tungsten halogen lamps.

Analysis of colour stability of selected provisional prosthetic materials: an in vitro study.

PubMed

Koczorowski, Ryszard; Linkowska-Swidzińska, Kamila; Gedrange, Tomasz; Swidziński, Teodor

2009-08-01

Prosthetic restorative materials (that are) used for temporary fixed dentures tend to exhibit variable discolouration over several weeks of use. The aim of this study was to perform a spectrophotometric analysis of the influence of selected discolouring factors on the colour stability of provisional prosthetic materials in vitro. In the study, the following prosthetic materials for short-term use in the oral cavity were evaluated: Luxatemp, Structur 2S.C., Protemp II, Zhermacryl STC and Dentalon Plus. Samples of these materials were immersed in coffee, tea and dark fruit juice for 60 h at different pH values. Colour was evaluated by determining the monochromatic coefficients of light reflected by the samples, using a spectrophotometric method. Results received in artificial light (illuminant A) were compared with those obtained in daylight (illuminant D65). Changes in colour and its parameters according to the CIE L*a*b* system were analysed. The analysis (of the colour and colour parameters) of the tested materials in two types of light showed that Structur displayed the greatest tendency to discolouration and that the least tendency to discolouration was exhibited by Dentalon Plus. The fact that colour parameters obtained in two types of light were not identical suggests that changes in the colour of the same material may be perceived differently, depending on the illuminant. Provisional prosthetic materials show variable colour stability under different conditions in the oral cavity. The colour of prosthetic materials may be perceived differently, depending on the illuminant and the effect of the environment in which they are used.

Effect of font size, italics, and colour count on web usability.

PubMed

Bhatia, Sanjiv K; Samal, Ashok; Rajan, Nithin; Kiviniemi, Marc T

2011-04-01

Web usability measures the ease of use of a website. This study attempts to find the effect of three factors - font size, italics, and colour count - on web usability. The study was performed using a set of tasks and developing a survey questionnaire. We performed the study using a set of human subjects, selected from the undergraduate students taking courses in psychology. The data computed from the tasks and survey questionnaire were statistically analysed to find if there was any effect of font size, italics, and colour count on the three web usability dimensions. We found that for the student population considered, there was no significant effect of font size on usability. However, the manipulation of italics and colour count did influence some aspects of usability. The subjects performed better for pages with no italics and high italics compared to moderate italics. The subjects rated the pages that contained only one colour higher than the web pages with four or six colours. This research will help web developers better understand the effect of font size, italics, and colour count on web usability in general, and for young adults, in particular.

Effect of font size, italics, and colour count on web usability

PubMed Central

Samal, Ashok; Rajan, Nithin; Kiviniemi, Marc T.

2013-01-01

Web usability measures the ease of use of a website. This study attempts to find the effect of three factors – font size, italics, and colour count – on web usability. The study was performed using a set of tasks and developing a survey questionnaire. We performed the study using a set of human subjects, selected from the undergraduate students taking courses in psychology. The data computed from the tasks and survey questionnaire were statistically analysed to find if there was any effect of font size, italics, and colour count on the three web usability dimensions. We found that for the student population considered, there was no significant effect of font size on usability. However, the manipulation of italics and colour count did influence some aspects of usability. The subjects performed better for pages with no italics and high italics compared to moderate italics. The subjects rated the pages that contained only one colour higher than the web pages with four or six colours. This research will help web developers better understand the effect of font size, italics, and colour count on web usability in general, and for young adults, in particular. PMID:24358055

Mapping the timecourse of goal-directed attention to location and colour in human vision.

PubMed

Adams, Rachel C; Chambers, Christopher D

2012-03-01

Goal-directed attention prioritises perception of task-relevant stimuli according to location, features, or onset time. In this study we compared the behavioural timecourse of goal-directed selection to locations and colours by varying the stimulus-onset asynchrony (SOA) between cue and target in a strategic cueing paradigm. Participants reported the presence or absence of a target following prior information regarding its location or colour. Results revealed that preparatory selection by colour is more effective at enhancing perceptual sensitivity than selection by location, even though both types of cue provided equivalent overall information. More detailed analysis revealed that this advantage arose due a limitation of spatial attention in maintaining a sufficiently broad focus (>2°) for target detection across multiple stimuli. In contrast, when target stimuli fell within 2° of the spatial attention spotlight, the strategic advantages and speed of spatial and colour attention were equated. Our findings are consistent with the conclusion that, under spatially optimal conditions, prior spatial and colour information are equally proficient at guiding top-down selection. When spatial locations are ambiguous, however, colour-based selection is the more efficient mechanism. Copyright © 2012 Elsevier B.V. All rights reserved.

Evolution of colour-dependence of galaxy clustering up to z˜ 1.2 based on the data from the VVDS-Wide survey

NASA Astrophysics Data System (ADS)

Świetoń, Agnieszka; Pollo, Agnieszka; VVDS Team

2014-12-01

We discuss the dependence of galaxy clustering according to their colours up to z˜ 1.2. For that purpose we used one of the wide fields (F22) from the VIMOS-VLT Deep Survey (VVDS). For galaxies with absolute luminosities close to the characteristic Schechter luminosities M^* at a given redshift, we measured the projected two-point correlation function w_{p}(r_{p}) and we estimated the best-fit parameters for a single power-law model: ξ(r) = (r/r_0)^{-γ} , where r_0 is the correlation length and γ is the slope of correlation function. Our results show that red galaxies exhibit the strongest clustering in all epochs up to z˜ 1.2. Green valley represents the "intermediate" population and blue cloud shows the weakest clustering strength. We also compared the shape of w_p(r_p) for different galaxy populations. All three populations have different clustering properties on the small scales, similarly to the behaviour observed in the local catalogues.

Multiband optical variability of the blazar OJ 287 during its outbursts in 2015-2016

NASA Astrophysics Data System (ADS)

Gupta, Alok C.; Agarwal, Aditi; Mishra, Alka; Gaur, H.; Wiita, P. J.; Gu, M. F.; Kurtanidze, O. M.; Damljanovic, G.; Uemura, M.; Semkov, E.; Strigachev, A.; Bachev, R.; Vince, O.; Zhang, Z.; Villarroel, B.; Kushwaha, P.; Pandey, A.; Abe, T.; Chanishvili, R.; Chigladze, R. A.; Fan, J. H.; Hirochi, J.; Itoh, R.; Kanda, Y.; Kawabata, M.; Kimeridze, G. N.; Kurtanidze, S. O.; Latev, G.; Dimitrova, R. V. Muñoz; Nakaoka, T.; Nikolashvili, M. G.; Shiki, K.; Sigua, L. A.; Spassov, B.

2017-03-01

We present recent optical photometric observations of the blazar OJ 287 taken during 2015 September-2016 May. Our intense observations of the blazar started in 2015 November and continued until 2016 May and included detection of the large optical outburst in 2015 December that was predicted using the binary black hole model for OJ 287. For our observing campaign, we used a total of nine ground-based optical telescopes of which one is in Japan, one is in India, three are in Bulgaria, one is in Serbia, one is in Georgia, and two are in the USA. These observations were carried out in 102 nights with a total of ∼1000 image frames in BVRI bands, though the majority were in the R band. We detected a second comparably strong flare in 2016 March. In addition, we investigated multiband flux variations, colour variations, and spectral changes in the blazar on diverse time-scales as they are useful in understanding the emission mechanisms. We briefly discuss the possible physical mechanisms most likely responsible for the observed flux, colour, and spectral variability.

Shaded seafloor relief, backscatter strength, and surficial geology; German Bank, Scotian Shelf, offshore Nova Scotia

USGS Publications Warehouse

Todd, B.J.; Valentine, Page C.

2010-01-01

This map is part of a three-map series of German Bank, located on the Scotian Shelf off southern Nova Scotia.  This map is the product of a number of surveys (1997-2003) that used a multibeam sonar system to map 5321 km2 of the seafloor.  Other surveys collected geological data for scientific interpretation.  This map sheet shows the seafloor topography of German Bank in shaded-relief view and seafloor depth (coded by colour) at a scale of 1:1000,000.  Topographic contours generated from the multibeam data are shown (in white) on the colour-coded multibeam topography at a depth interval of 20 m.  Bathymetic contours (in blue) outside the multibeam survey area, presented at a depth interval of 10 m, are from the Natural Resource Map series (Canadian Hydrographic Service, 1967, 1971a, 1971b, 1972). Sheet 2 shows coloured backscatter strength in shaded-relief view.  Sheet 3 shows seafloor topography in shaded-relief view with colour-coded surficial geological units.

A novel colourimetric technique to assess chewing function using two-coloured specimens: Validation and application.

PubMed

Schimmel, Martin; Christou, Panagiotis; Miyazaki, Hideo; Halazonetis, Demetrios; Herrmann, François R; Müller, Frauke

2015-08-01

Chewing efficiency may be evaluated using cohesive specimen, especially in elderly or dysphagic patients. The aim of this study was to evaluate three two-coloured chewing gums for a colour-mixing ability test and to validate a new purpose built software (ViewGum©). Dentate participants (dentate-group) and edentulous patients with mandibular two-implant overdentures (IOD-group) were recruited. First, the dentate-group chewed three different types of two-coloured gum (gum1-gum3) for 5, 10, 20, 30 and 50 chewing cycles. Subsequently the number of chewing cycles with the highest intra- and inter-rater agreement was determined visually by applying a scale (SA) and opto-electronically (ViewGum©, Bland-Altman analysis). The ViewGum© software determines semi-automatically the variance of hue (VOH); inadequate mixing presents with larger VOH than complete mixing. Secondly, the dentate-group and the IOD-group were compared. The dentate-group comprised 20 participants (10 female, 30.3±6.7 years); the IOD-group 15 participants (10 female, 74.6±8.3 years). Intra-rater and inter-rater agreement (SA) was very high at 20 chewing cycles (95.00-98.75%). Gums 1-3 showed different colour-mixing characteristics as a function of chewing cycles, gum1 showed a logarithmic association; gum2 and gum3 demonstrated more linear behaviours. However, the number of chewing cycles could be predicted in all specimens from VOH (all p<0.0001, mixed linear regression models). Both analyses proved discriminative to the dental state. ViewGum© proved to be a reliable and discriminative tool to opto-electronically assess chewing efficiency, given an elastic specimen is chewed for 20 cycles and could be recommended for the evaluation of chewing efficiency in a clinical and research setting. Chewing is a complex function of the oro-facial structures and the central nervous system. The application of the proposed assessments of the chewing function in geriatrics or special care dentistry could help visualising oro-functional or dental comorbidities in dysphagic patients or those suffering from protein-energy malnutrition. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Chromatic illumination discrimination ability reveals that human colour constancy is optimised for blue daylight illuminations.

PubMed

Pearce, Bradley; Crichton, Stuart; Mackiewicz, Michal; Finlayson, Graham D; Hurlbert, Anya

2014-01-01

The phenomenon of colour constancy in human visual perception keeps surface colours constant, despite changes in their reflected light due to changing illumination. Although colour constancy has evolved under a constrained subset of illuminations, it is unknown whether its underlying mechanisms, thought to involve multiple components from retina to cortex, are optimised for particular environmental variations. Here we demonstrate a new method for investigating colour constancy using illumination matching in real scenes which, unlike previous methods using surface matching and simulated scenes, allows testing of multiple, real illuminations. We use real scenes consisting of solid familiar or unfamiliar objects against uniform or variegated backgrounds and compare discrimination performance for typical illuminations from the daylight chromaticity locus (approximately blue-yellow) and atypical spectra from an orthogonal locus (approximately red-green, at correlated colour temperature 6700 K), all produced in real time by a 10-channel LED illuminator. We find that discrimination of illumination changes is poorer along the daylight locus than the atypical locus, and is poorest particularly for bluer illumination changes, demonstrating conversely that surface colour constancy is best for blue daylight illuminations. Illumination discrimination is also enhanced, and therefore colour constancy diminished, for uniform backgrounds, irrespective of the object type. These results are not explained by statistical properties of the scene signal changes at the retinal level. We conclude that high-level mechanisms of colour constancy are biased for the blue daylight illuminations and variegated backgrounds to which the human visual system has typically been exposed.

Effects of Congruent and Incongruent Stimulus Colour on Flavour Discriminations.

PubMed

Wieneke, Leonie; Schmuck, Pauline; Zacher, Julia; Greenlee, Mark W; Plank, Tina

2018-01-01

In addition to gustatory, olfactory and somatosensory input, visual information plays a role in our experience of food and drink. We asked whether colour in this context has an effect at the perceptual level via multisensory integration or if higher level cognitive factors are involved. Using an articulatory suppression task, comparable to Stevenson and Oaten, cognitive processes should be interrupted during a flavour discriminatory task, so that any residual colour effects would be traceable to low-level integration. Subjects judged in a three-alternative forced-choice paradigm the presence of a different flavour (triangle test). On each trial, they tasted three liquids from identical glasses, with one of them containing a different flavour. The substances were congruent in colour and flavour, incongruent or uncoloured. Subjects who performed the articulatory suppression task responded faster and made fewer errors. The findings suggest a role for higher level cognitive processing in the effect of colour on flavour judgements.

Effects of Congruent and Incongruent Stimulus Colour on Flavour Discriminations

PubMed Central

Wieneke, Leonie; Schmuck, Pauline; Zacher, Julia; Plank, Tina

2018-01-01

In addition to gustatory, olfactory and somatosensory input, visual information plays a role in our experience of food and drink. We asked whether colour in this context has an effect at the perceptual level via multisensory integration or if higher level cognitive factors are involved. Using an articulatory suppression task, comparable to Stevenson and Oaten, cognitive processes should be interrupted during a flavour discriminatory task, so that any residual colour effects would be traceable to low-level integration. Subjects judged in a three-alternative forced-choice paradigm the presence of a different flavour (triangle test). On each trial, they tasted three liquids from identical glasses, with one of them containing a different flavour. The substances were congruent in colour and flavour, incongruent or uncoloured. Subjects who performed the articulatory suppression task responded faster and made fewer errors. The findings suggest a role for higher level cognitive processing in the effect of colour on flavour judgements. PMID:29755721

Polarization-independent actively tunable colour generation on imprinted plasmonic surfaces

PubMed Central

Franklin, Daniel; Chen, Yuan; Vazquez-Guardado, Abraham; Modak, Sushrut; Boroumand, Javaneh; Xu, Daming; Wu, Shin-Tson; Chanda, Debashis

2015-01-01

Structural colour arising from nanostructured metallic surfaces offers many benefits compared to conventional pigmentation based display technologies, such as increased resolution and scalability of their optical response with structure dimensions. However, once these structures are fabricated their optical characteristics remain static, limiting their potential application. Here, by using a specially designed nanostructured plasmonic surface in conjunction with high birefringence liquid crystals, we demonstrate a tunable polarization-independent reflective surface where the colour of the surface is changed as a function of applied voltage. A large range of colour tunability is achieved over previous reports by utilizing an engineered surface which allows full liquid crystal reorientation while maximizing the overlap between plasmonic fields and liquid crystal. In combination with imprinted structures of varying periods, a full range of colours spanning the entire visible spectrum is achieved, paving the way towards dynamic pixels for reflective displays. PMID:26066375

Gender differences in colour naming performance for gender specific body shape images.

PubMed

Elliman, N A; Green, M W; Wan, W K

1998-03-01

Males are increasingly subjected to pressures to conform to aesthetic body stereotypes. There is, however, comparatively little published research on the aetiology of male body shape concerns. Two experiments are presented, which investigate the relationship between gender specific body shape concerns and colour-naming performance. Each study comprised a between subject design, in which each subject was tested on a single occasion. A pictorial version of a modified Stroop task was used in both studies. Subjects colour-named gender specific obese and thin body shape images and semantically homogeneous neutral images (birds) presented in a blocked format. The first experiment investigated female subjects (N = 68) and the second investigated males (N = 56). Subjects also completed a self-report measure of eating behaviour. Currently dieting female subjects exhibited significant colour-naming differences between obese and neutral images. A similar pattern of colour-naming performance was found to be related to external eating in the male subjects.

Anthocyanin and antioxidant activity of snacks with coloured potato.

PubMed

Nemś, Agnieszka; Pęksa, Anna; Kucharska, Alicja Z; Sokół-Łętowska, Anna; Kita, Agnieszka; Drożdż, Wioletta; Hamouz, Karel

2015-04-01

Coloured-fleshed potatoes of four varieties were used as raw material for coloured flour and fried snack production. The effects of thermal processes traditionally used in dried potato processing and in snack pellet manufacturing on anthocyanin profiles, total polyphenols and antioxidant properties of obtained half- and ready products were studied. There was a significant influence of potato variety on the experimental flour and snack properties. Flours with the highest antioxidant activities were obtained from Salad Blue and Herbie 26 potatoes; however, the flour prepared from the Blue Congo exhibited a much higher total polyphenol and anthocyanin content. Snacks produced with coloured flour had 2-3 times higher antioxidant activities, 40% higher contents of polyphenols, attractive colour and better expansion compared to control samples. The lowest losses of anthocyanins during snack processing were in snacks with flour from the purple-fleshed Blue Congo and red-fleshed Herbie 26. Copyright © 2014 Elsevier Ltd. All rights reserved.

Revisiting the co-existence of Attention-Deficit/Hyperactivity Disorder and Chronic Tic Disorder in childhood-The case of colour discrimination, sustained attention and interference control.

PubMed

Uebel-von Sandersleben, Henrik; Albrecht, Björn; Rothenberger, Aribert; Fillmer-Heise, Anke; Roessner, Veit; Sergeant, Joseph; Tannock, Rosemary; Banaschewski, Tobias

2017-01-01

Attention Deficit / Hyperactivity Disorder (ADHD) and Chronic Tic Disorder (CTD) are two common and frequently co-existing disorders, probably following an additive model. But this is not yet clear for the basic sensory function of colour processing sensitive to dopaminergic functioning in the retina and higher cognitive functions like attention and interference control. The latter two reflect important aspects for psychoeducation and behavioural treatment approaches. Colour discrimination using the Farnsworth-Munsell 100-hue Test, sustained attention during the Frankfurt Attention Inventory (FAIR), and interference liability during Colour- and Counting-Stroop-Tests were assessed to further clarify the cognitive profile of the co-existence of ADHD and CTD. Altogether 69 children were classified into four groups: ADHD (N = 14), CTD (N = 20), ADHD+CTD (N = 20) and healthy Controls (N = 15) and compared in cognitive functioning in a 2×2-factorial statistical model. Difficulties with colour discrimination were associated with both ADHD and CTD factors following an additive model, but in ADHD these difficulties tended to be more pronounced on the blue-yellow axis. Attention problems were characteristic for ADHD but not CTD. Interference load was significant in both Colour- and Counting-Stroop-Tests and unrelated to colour discrimination. Compared to Controls, interference load in the Colour-Stroop was higher in pure ADHD and in pure CTD, but not in ADHD+CTD, following a sub-additive model. In contrast, interference load in the Counting-Stroop did not reveal ADHD or CTD effects. The co-existence of ADHD and CTD is characterized by additive as well as sub-additive performance impairments, suggesting that their co-existence may show simple additive characteristics of both disorders or a more complex interaction, depending on demand. The equivocal findings on interference control may indicate limited validity of the Stroop-Paradigm for clinical assessments.

Psychophysical Evaluation of Congenital Colour Vision Deficiency: Discrimination between Protans and Deutans Using Mollon-Reffin’s Ellipses and the Farnsworth-Munsell 100-Hue Test

PubMed Central

Bento-Torres, Natáli Valim Oliver; Rodrigues, Anderson Raiol; Côrtes, Maria Izabel Tentes; Bonci, Daniela Maria de Oliveira; Ventura, Dora Fix

2016-01-01

We have used the Farnsworth-Munsell 100-hue (FM 100) test and Mollon-Reffin (MR) test to evaluate the colour vision of 93 subjects, 30.4 ± 9.7 years old, who had red-green congenital colour vision deficiencies. All subjects lived in Belém (State of Pará, Brazil) and were selected by the State of Pará Traffic Department. Selection criteria comprised the absence of visual dysfunctions other than Daltonism and no history of systemic diseases that could impair the visual system performance. Results from colour vision deficient were compared with those from 127 normal trichromats, 29.3 ± 10.3 years old. For the MR test, measurements were taken around five points of the CIE 1976 colour space, along 20 directions irradiating from each point, in order to determine with high-resolution the corresponding colour discrimination ellipses (MacAdam ellipses). Three parameters were used to compare results obtained from different subjects: diameter of circle with same ellipse area, ratio between ellipse’s long and short axes, and ellipse long axis angle. For the FM 100 test, the parameters were: logarithm of the total number of mistakes and positions of mistakes in the FM diagram. Data were also simultaneously analysed in two or three dimensions as well as by using multidimensional cluster analysis. For the MR test, Mollon-Reffin Ellipse #3 (u’ = 0.225, v’ = 0.415) discriminated more efficiently than the other four ellipses between protans and deutans once it provided larger angular difference in the colour space between protan and deutan confusion lines. The MR test was more sensitive than the FM 100 test. It separated individuals by dysfunctional groups with greater precision, provided a more sophisticated quantitative analysis, and its use is appropriate for a more refined evaluation of different phenotypes of red-green colour vision deficiencies. PMID:27101124

The effect of colouring agent on the physical properties of glass ceramic produced from waste glass for antimicrobial coating deposition

NASA Astrophysics Data System (ADS)

Juoi, J. M.; Ayoob, N. F.; Rosli, Z. M.; Rosli, N. R.; Husain, K.

2016-07-01

Domestic waste glass is utilized as raw material for the production of glass ceramic material (GCM) via sinter crystallisation route. The glass ceramic material in a form of tiles is to be utilized for the deposition of Ag-TiO2 antimicrobial coating. Two types of soda lime glass (SLG) that are non-coloured and green SLG are utilised as main raw materials during the batch formulation in order to study the effect of colouring agent (Fe2O3) on the physical and mechanical properties of glass ceramic produced. Glass powder were prepared by crushing bottles using hammer milled with milling machine and sieved until they passed through 75 µm sieve. The process continues by mixing glass powder with ball clay with ratio of 95:5 wt. %, 90:10 wt. % and 85:15 wt. %. Each batch mixture was then uniaxial pressed and sintered at 800°C, 825 °C and 850 °C. The physical and mechanical properties were then determined and compared between those produced from non-coloured and green coloured SLG in order to evaluate the effect of colouring agent (Fe2O3) on the GCM produced. The optimum properties of non-coloured SLG is produced with smaller ball clay content (10 wt. %) compared to green SLG (15 wt. %). The physical properties (determined thru ASTM C373) of the optimized GCM produced from non-coloured SLG and green SLG are 0.69 % of porosity, 1.92 g/cm3 of bulk density, 0.36 % of water absorption; and 1.96 % of porosity, 2.69 g/cm3 of bulk density, 0.73 % of water absorption; respectively. Results also indicate that the most suitable temperature in producing GCM from both glasses with optimized physical and mechanical properties is at 850 °C.

Psychophysical Evaluation of Congenital Colour Vision Deficiency: Discrimination between Protans and Deutans Using Mollon-Reffin's Ellipses and the Farnsworth-Munsell 100-Hue Test.

PubMed

Bento-Torres, Natáli Valim Oliver; Rodrigues, Anderson Raiol; Côrtes, Maria Izabel Tentes; Bonci, Daniela Maria de Oliveira; Ventura, Dora Fix; Silveira, Luiz Carlos de Lima

2016-01-01

We have used the Farnsworth-Munsell 100-hue (FM 100) test and Mollon-Reffin (MR) test to evaluate the colour vision of 93 subjects, 30.4 ± 9.7 years old, who had red-green congenital colour vision deficiencies. All subjects lived in Belém (State of Pará, Brazil) and were selected by the State of Pará Traffic Department. Selection criteria comprised the absence of visual dysfunctions other than Daltonism and no history of systemic diseases that could impair the visual system performance. Results from colour vision deficient were compared with those from 127 normal trichromats, 29.3 ± 10.3 years old. For the MR test, measurements were taken around five points of the CIE 1976 colour space, along 20 directions irradiating from each point, in order to determine with high-resolution the corresponding colour discrimination ellipses (MacAdam ellipses). Three parameters were used to compare results obtained from different subjects: diameter of circle with same ellipse area, ratio between ellipse's long and short axes, and ellipse long axis angle. For the FM 100 test, the parameters were: logarithm of the total number of mistakes and positions of mistakes in the FM diagram. Data were also simultaneously analysed in two or three dimensions as well as by using multidimensional cluster analysis. For the MR test, Mollon-Reffin Ellipse #3 (u' = 0.225, v' = 0.415) discriminated more efficiently than the other four ellipses between protans and deutans once it provided larger angular difference in the colour space between protan and deutan confusion lines. The MR test was more sensitive than the FM 100 test. It separated individuals by dysfunctional groups with greater precision, provided a more sophisticated quantitative analysis, and its use is appropriate for a more refined evaluation of different phenotypes of red-green colour vision deficiencies.

Revisiting the co-existence of Attention-Deficit/Hyperactivity Disorder and Chronic Tic Disorder in childhood—The case of colour discrimination, sustained attention and interference control

PubMed Central

Rothenberger, Aribert; Fillmer-Heise, Anke; Roessner, Veit; Sergeant, Joseph; Tannock, Rosemary; Banaschewski, Tobias

2017-01-01

Objective Attention Deficit / Hyperactivity Disorder (ADHD) and Chronic Tic Disorder (CTD) are two common and frequently co-existing disorders, probably following an additive model. But this is not yet clear for the basic sensory function of colour processing sensitive to dopaminergic functioning in the retina and higher cognitive functions like attention and interference control. The latter two reflect important aspects for psychoeducation and behavioural treatment approaches. Methods Colour discrimination using the Farnsworth-Munsell 100-hue Test, sustained attention during the Frankfurt Attention Inventory (FAIR), and interference liability during Colour- and Counting-Stroop-Tests were assessed to further clarify the cognitive profile of the co-existence of ADHD and CTD. Altogether 69 children were classified into four groups: ADHD (N = 14), CTD (N = 20), ADHD+CTD (N = 20) and healthy Controls (N = 15) and compared in cognitive functioning in a 2×2-factorial statistical model. Results Difficulties with colour discrimination were associated with both ADHD and CTD factors following an additive model, but in ADHD these difficulties tended to be more pronounced on the blue-yellow axis. Attention problems were characteristic for ADHD but not CTD. Interference load was significant in both Colour- and Counting-Stroop-Tests and unrelated to colour discrimination. Compared to Controls, interference load in the Colour-Stroop was higher in pure ADHD and in pure CTD, but not in ADHD+CTD, following a sub-additive model. In contrast, interference load in the Counting-Stroop did not reveal ADHD or CTD effects. Conclusion The co-existence of ADHD and CTD is characterized by additive as well as sub-additive performance impairments, suggesting that their co-existence may show simple additive characteristics of both disorders or a more complex interaction, depending on demand. The equivocal findings on interference control may indicate limited validity of the Stroop-Paradigm for clinical assessments. PMID:28594866

Colour Stability of Various Types of Acrylic Teeth Exposed to Coffee, Tea and Cola

PubMed Central

S, Mousavi; S, Narimani; S, Hekmatfar; K, Jafari

2016-01-01

Statement of Problem: Acrylic teeth of dentures are prone to discoloration due to frequent exposure to different colouring solutions in the oral environment. Thus, in order to maintain their aesthetic appearance, they must possess high colour stability while exposed to colorant solutions. Objectives: To compare the colour stability of three different brands of acrylic teeth following immersion in coffee, tea and cola. Materials and Methods: This in vitro experimental study was conducted on 90 acrylic teeth in three groups (n = 30) of Ivoclar (Italy), PolyDent (Slovenia) and Apple (Iran). The teeth were immersed in coffee, cola and tea for one, three and six weeks (the teeth were not in contact with each other). Colour parameters were assessed before and after immersion using a spectrophotometer, and overall change in colour parameters was calculated. The overall colour change (ΔE) of the three groups at different time points was analyzed using one-way ANOVA. Pairwise comparisons were performed using Tukey’s test. Results: Coffee caused the greatest colour change in Apple acrylic teeth after six weeks (mean ΔE of 4.6 for coffee and 3.4 for tea and cola). Tea caused an almost equal colour change in the three groups. The greatest colour change in the Ivoclar teeth occurred in cola after six weeks (mean ΔE of 3.3, 3.4 and 2.8 for cola, tea and coffee, respectively). The greatest ΔE occurred at six weeks and was the highest in Apple, followed by PolyDent and then Ivoclar teeth in coffee (mean ΔE of 4.6, 3.4 and 3.3, respectively p < 0.001). Conclusions: Despite the significant colour change in the three groups, ΔE in Ivoclar group was within the clinically acceptable range of ≤ 3.3. A slight colour change was expected regarding the Apple and PolyDent acrylic teeth clinically. PMID:28959762

Colour Stability of Various Types of Acrylic Teeth Exposed to Coffee, Tea and Cola.

PubMed

S, Mousavi; S, Narimani; S, Hekmatfar; K, Jafari

2016-12-01

Acrylic teeth of dentures are prone to discoloration due to frequent exposure to different colouring solutions in the oral environment. Thus, in order to maintain their aesthetic appearance, they must possess high colour stability while exposed to colorant solutions. To compare the colour stability of three different brands of acrylic teeth following immersion in coffee, tea and cola. This in vitro experimental study was conducted on 90 acrylic teeth in three groups (n = 30) of Ivoclar (Italy), PolyDent (Slovenia) and Apple (Iran). The teeth were immersed in coffee, cola and tea for one, three and six weeks (the teeth were not in contact with each other). Colour parameters were assessed before and after immersion using a spectrophotometer, and overall change in colour parameters was calculated. The overall colour change (ΔE) of the three groups at different time points was analyzed using one-way ANOVA. Pairwise comparisons were performed using Tukey's test. Coffee caused the greatest colour change in Apple acrylic teeth after six weeks (mean ΔE of 4.6 for coffee and 3.4 for tea and cola). Tea caused an almost equal colour change in the three groups. The greatest colour change in the Ivoclar teeth occurred in cola after six weeks (mean ΔE of 3.3, 3.4 and 2.8 for cola, tea and coffee, respectively). The greatest ΔE occurred at six weeks and was the highest in Apple, followed by PolyDent and then Ivoclar teeth in coffee (mean ΔE of 4.6, 3.4 and 3.3, respectively p < 0.001). Despite the significant colour change in the three groups, ΔE in Ivoclar group was within the clinically acceptable range of ≤ 3.3. A slight colour change was expected regarding the Apple and PolyDent acrylic teeth clinically.

Colour distributions in E-S0 galaxies . IV. Colour data and dust in E's from Nieto's B, R frames

NASA Astrophysics Data System (ADS)

Michard, R.

1999-06-01

The B-R colours distributions (with R in Cousins's system) have been measured in 44 E classified galaxies in the Local Supercluster, from pairs of frames collected by Nieto and co-workers in 1989-91. These are nearly all from the CFHT, and of sub-arsec resolution. Great attention has been given to the effects of unequal PSF's in the B and R frames upon colour distributions near centre; such effects are illustrated from model calculations and from pseudo-colours obtained from pairs of frames taken in the same band but with different seeing conditions. Appropriate corrections were systematically applied in order to derive central colours and inner gradients, although still affected by the limited resolution of the frames. The radial colour distributions have been measured in more detail than usual, considering separately the near major axis and near minor axis regions of the isophotal contours. Azimuthal colour distributions, in rings limited by selected isophotes, were also obtained. Dust ``patterns", i.e. patches, lanes, arcs, ..., have been detected and mapped from the colour distributions. An ad hoc dust pattern importance index (or DPII) in a scale of 0 to 3, has been introduced to qualify their size and contrast. We have tried to find evidence of a diffuse dust concentration towards the disk, if one is apparent. Positive results (noted by the dd symbol) have been obtained for disky E's, whenever the inclination of their disk to the line of sight is large enough, and eventually also in the small isolated disks sometimes present in both boxy and disky galaxies. The red central peak occurring in many E-galaxies might be the signature of a central concentration of dust, also in cases where this peak is isolated rather than embedded in some extensive colour pattern. The properties of the near centre colour profiles have been related to a classification of nuclear photometric profiles into ``flat topped" and ``sharply peaked" (equivalent to ``core-like" and ``power-law" in the terminology of te[Faber et al. 1997).]{fab97} The published here data include the following: . Short descriptions and codes for the characters of the B-R distribution of each object, and comparison to the results of recent surveys. . A table of the mean B-R at the centre and at two selected isophotes, a ``core colour gradient" and the usual logarithmic gradient. . Maps of near core B-R isochromes and B isophotes for comparison. Images of the B-R colour distribution are made available in electronic form. Based on observations collected at the Canada-France-Hawaii Telescope and at the Observatoire du Pic du Midi.

Modelling ocean-colour-derived chlorophyll a

NASA Astrophysics Data System (ADS)

Dutkiewicz, Stephanie; Hickman, Anna E.; Jahn, Oliver

2018-01-01

This article provides a proof of concept for using a biogeochemical/ecosystem/optical model with a radiative transfer component as a laboratory to explore aspects of ocean colour. We focus here on the satellite ocean colour chlorophyll a (Chl a) product provided by the often-used blue/green reflectance ratio algorithm. The model produces output that can be compared directly to the real-world ocean colour remotely sensed reflectance. This model output can then be used to produce an ocean colour satellite-like Chl a product using an algorithm linking the blue versus green reflectance similar to that used for the real world. Given that the model includes complete knowledge of the (model) water constituents, optics and reflectance, we can explore uncertainties and their causes in this proxy for Chl a (called derived Chl a in this paper). We compare the derived Chl a to the actual model Chl a field. In the model we find that the mean absolute bias due to the algorithm is 22 % between derived and actual Chl a. The real-world algorithm is found using concurrent in situ measurement of Chl a and radiometry. We ask whether increased in situ measurements to train the algorithm would improve the algorithm, and find a mixed result. There is a global overall improvement, but at the expense of some regions, especially in lower latitudes where the biases increase. Not surprisingly, we find that region-specific algorithms provide a significant improvement, at least in the annual mean. However, in the model, we find that no matter how the algorithm coefficients are found there can be a temporal mismatch between the derived Chl a and the actual Chl a. These mismatches stem from temporal decoupling between Chl a and other optically important water constituents (such as coloured dissolved organic matter and detrital matter). The degree of decoupling differs regionally and over time. For example, in many highly seasonal regions, the timing of initiation and peak of the spring bloom in the derived Chl a lags the actual Chl a by days and sometimes weeks. These results indicate that care should also be taken when studying phenology through satellite-derived products of Chl a. This study also reemphasizes that ocean-colour-derived Chl a is not the same as the real in situ Chl a. In fact the model derived Chl a compares better to real-world satellite-derived Chl a than the model actual Chl a. Modellers should keep this is mind when evaluating model output with ocean colour Chl a and in particular when assimilating this product. Our goal is to illustrate the use of a numerical laboratory that (a) helps users of ocean colour, particularly modellers, gain further understanding of the products they use and (b) helps the ocean colour community to explore other ocean colour products, their biases and uncertainties, as well as to aid in future algorithm development.

Colour-specific differences in attentional deployment for equiluminant pop-out colours: evidence from lateralised potentials.

PubMed

Pomerleau, Vincent Jetté; Fortier-Gauthier, Ulysse; Corriveau, Isabelle; Dell'Acqua, Roberto; Jolicœur, Pierre

2014-03-01

We investigated how target colour affected behavioural and electrophysiological results in a visual search task. Perceptual and attentional mechanisms were tracked using the N2pc component of the event-related potential and other lateralised components. Four colours (red, green, blue, or yellow) were calibrated for each participant for luminance through heterochromatic flicker photometry and equated to the luminance of grey distracters. Each visual display contained 10 circles, 1 colored and 9 grey, each of which contained an oriented line segment. The task required deploying attention to the colored circle, which was either in the left or right visual hemifield. Three lateralised ERP components relative to the side of the lateral coloured circle were examined: a posterior contralateral positivity (Ppc) prior to N2pc, the N2pc, reflecting the deployment of visual spatial attention, and a temporal and contralateral positivity (Ptc) following N2pc. Red or blue stimuli, as compared to green or yellow, had an earlier N2pc. Both the Ppc and Ptc had higher amplitudes to red stimuli, suggesting particular selectivity for red. The results suggest that attention may be deployed to red and blue more quickly than to other colours and suggests special caution when designing ERP experiments involving stimuli in different colours, even when all colours are equiluminant. Copyright © 2013 Elsevier B.V. All rights reserved.

Evaluating a novel application of optical fibre evanescent field absorbance: rapid measurement of red colour in winegrape homogenates

NASA Astrophysics Data System (ADS)

Lye, Peter G.; Bradbury, Ronald; Lamb, David W.

Silica optical fibres were used to measure colour (mg anthocyanin/g fresh berry weight) in samples of red wine grape homogenates via optical Fibre Evanescent Field Absorbance (FEFA). Colour measurements from 126 samples of grape homogenate were compared against the standard industry spectrophotometric reference method that involves chemical extraction and subsequent optical absorption measurements of clarified samples at 520 nm. FEFA absorbance on homogenates at 520 nm (FEFA520h) was correlated with the industry reference method measurements of colour (R2 = 0.46, n = 126). Using a simple regression equation colour could be predicted with a standard error of cross-validation (SECV) of 0.21 mg/g, with a range of 0.6 to 2.2 mg anthocyanin/g and a standard deviation of 0.33 mg/g. With a Ratio of Performance Deviation (RPD) of 1.6, the technique when utilizing only a single detection wavelength, is not robust enough to apply in a diagnostic sense, however the results do demonstrate the potential of the FEFA method as a fast and low-cost assay of colour in homogenized samples.

Herschel-ATLAS: Dust Temperature and Redshift Distribution of SPIRE and PACS Detected Sources Using Submillimetre Colours

NASA Technical Reports Server (NTRS)

Amblard, A.; Cooray, Asantha; Serra, P.; Temi, P.; Barton, E.; Negrello, M.; Auld, R.; Baes, M.; Baldry, I. K.; Bamford, S.;

The Categorisation of Non-Categorical Colours: A Novel Paradigm in Colour Perception

PubMed Central

Cropper, Simon J.; Kvansakul, Jessica G. S.; Little, Daniel R.

2013-01-01

In this paper, we investigate a new paradigm for studying the development of the colour ‘signal’ by having observers discriminate and categorize the same set of controlled and calibrated cardinal coloured stimuli. Notably, in both tasks, each observer was free to decide whether two pairs of colors were the same or belonged to the same category. The use of the same stimulus set for both tasks provides, we argue, an incremental behavioural measure of colour processing from detection through discrimination to categorisation. The measured data spaces are different for the two tasks, and furthermore the categorisation data is unique to each observer. In addition, we develop a model which assumes that the principal difference between the tasks is the degree of similarity between the stimuli which has different constraints for the categorisation task compared to the discrimination task. This approach not only makes sense of the current (and associated) data but links the processes of discrimination and categorisation in a novel way and, by implication, expands upon the previous research linking categorisation to other tasks not limited to colour perception. PMID:23536899

The categorisation of non-categorical colours: a novel paradigm in colour perception.

PubMed

Cropper, Simon J; Kvansakul, Jessica G S; Little, Daniel R

2013-01-01

In this paper, we investigate a new paradigm for studying the development of the colour 'signal' by having observers discriminate and categorize the same set of controlled and calibrated cardinal coloured stimuli. Notably, in both tasks, each observer was free to decide whether two pairs of colors were the same or belonged to the same category. The use of the same stimulus set for both tasks provides, we argue, an incremental behavioural measure of colour processing from detection through discrimination to categorisation. The measured data spaces are different for the two tasks, and furthermore the categorisation data is unique to each observer. In addition, we develop a model which assumes that the principal difference between the tasks is the degree of similarity between the stimuli which has different constraints for the categorisation task compared to the discrimination task. This approach not only makes sense of the current (and associated) data but links the processes of discrimination and categorisation in a novel way and, by implication, expands upon the previous research linking categorisation to other tasks not limited to colour perception.

How hollow melanosomes affect iridescent colour production in birds

PubMed Central

Eliason, Chad M.; Bitton, Pierre-Paul; Shawkey, Matthew D.

2013-01-01

Developmental constraints and trade-offs can limit diversity, but organisms have repeatedly evolved morphological innovations that overcome these limits by expanding the range and functionality of traits. Iridescent colours in birds are commonly produced by melanin-containing organelles (melanosomes) organized into nanostructured arrays within feather barbules. Variation in array type (e.g. multilayers and photonic crystals, PCs) is known to have remarkable effects on plumage colour, but the optical consequences of variation in melanosome shape remain poorly understood. Here, we used a combination of spectrophotometric, experimental and theoretical methods to test how melanosome hollowness—a morphological innovation largely restricted to birds—affects feather colour. Optical analyses of hexagonal close-packed arrays of hollow melanosomes in two species, wild turkeys (Meleagris gallopavo) and violet-backed starlings (Cinnyricinclus leucogaster), indicated that they function as two-dimensional PCs. Incorporation of a larger dataset and optical modelling showed that, compared with solid melanosomes, hollow melanosomes allow birds to produce distinct colours with the same energetically favourable, close-packed configurations. These data suggest that a morphological novelty has, at least in part, allowed birds to achieve their vast morphological and colour diversity. PMID:23902909

It is all in the face: carotenoid skin coloration loses attractiveness outside the face.

PubMed

Lefevre, C E; Ewbank, M P; Calder, A J; von dem Hagen, E; Perrett, D I

2013-01-01

Recently, the importance of skin colour for facial attractiveness has been recognized. In particular, dietary carotenoid-induced skin colour has been proposed as a signal of health and therefore attractiveness. While perceptual results are highly consistent, it is currently not clear whether carotenoid skin colour is preferred because it poses a cue to current health condition in humans or whether it is simply seen as a more aesthetically pleasing colour, independently of skin-specific signalling properties. Here, we tested this question by comparing attractiveness ratings of faces to corresponding ratings of meaningless scrambled face images matching the colours and contrasts found in the face. We produced sets of face and non-face stimuli with either healthy (high-carotenoid coloration) or unhealthy (low-carotenoid coloration) colour and asked participants for attractiveness ratings. Results showed that, while for faces increased carotenoid coloration significantly improved attractiveness, there was no equivalent effect on perception of scrambled images. These findings are consistent with a specific signalling system of current condition through skin coloration in humans and indicate that preferences are not caused by sensory biases in observers.

Effect of alternative preservatives on the microbial quality, lipid stability and sensory evaluation of boerewors.

PubMed

Mathenjwa, S A; Hugo, C J; Bothma, C; Hugo, A

2012-06-01

Boerewors is a South African fresh sausage preserved with 450mg/kg sulphur dioxide (SO(2)). The preservative effects of rosemary (Ros; 260mg/kg) and chitosan (Chi; 10g/kg) were compared to SO(2). Eight boerewors models were formulated. Microbial, colour, lipid and sensory characteristics were evaluated. Chi and Chi in combination with other preservatives had a significant effect on reducing total bacterial, coliform and Enterobacteriaceae counts, comparable to SO(2). Chi, however, had a better effect on decreasing yeasts and mould counts than SO(2). Chi showed good colour properties comparable to SO(2). Ros showed comparable lipid stability to SO(2) but better when compared to Chi. Ros had a better effect on the sensory taste when compared to Chi, but SO(2) was still preferred. Reduced levels of 100mg/kg SO(2) showed good antimicrobial and colour effects in combination with Chi and in combination with Ros as antioxidant and improving the sensory properties. Alternative preservatives can be used to reduce the SO(2) content of boerewors. Copyright © 2012 Elsevier Ltd. All rights reserved.

Low Predictability of Colour Polymorphism in Introduced Guppy (Poecilia reticulata) Populations in Panama

PubMed Central

Martínez, Celestino; Chavarría, Carmen; Sharpe, Diana M. T.; De León, Luis Fernando

2016-01-01

Colour polymorphism is a recurrent feature of natural populations, and its maintenance has been studied in a range of taxa in their native ranges. However, less is known about whether (and how) colour polymorphism is maintained when populations are removed from their native environments, as in the case of introduced species. We here address this issue by analyzing variation in colour patterns in recently-discovered introduced populations of the guppy (Poecilia reticulata) in Panama. Specifically, we use classic colour analysis to estimate variation in the number and the relative area of different colour spots across low predation sites in the introduced Panamanian range of the species. We then compare this variation to that found in the native range of the species under low- and high predation regimes. We found aspects of the colour pattern that were both consistent and inconsistent with the classical paradigm of colour evolution in guppies. On one hand, the same colours that dominated in native populations (orange, iridescent and black) were also the most dominant in the introduced populations in Panama. On the other, there were no clear differences between either introduced-low and native low- and high predation populations. Our results are therefore only partially consistent with the traditional role of female preference in the absence of predators, and suggest that additional factors could influence colour patterns when populations are removed from their native environments. Future research on the interaction between female preference and environmental variability (e.g. multifarious selection), could help understand adaptive variation in this widely-introduced species, and the contexts under which variation in adaptive traits parallels (or not) variation in the native range. PMID:26863538

Low Predictability of Colour Polymorphism in Introduced Guppy (Poecilia reticulata) Populations in Panama.

PubMed

Martínez, Celestino; Chavarría, Carmen; Sharpe, Diana M T; De León, Luis Fernando

2016-01-01

Colour polymorphism is a recurrent feature of natural populations, and its maintenance has been studied in a range of taxa in their native ranges. However, less is known about whether (and how) colour polymorphism is maintained when populations are removed from their native environments, as in the case of introduced species. We here address this issue by analyzing variation in colour patterns in recently-discovered introduced populations of the guppy (Poecilia reticulata) in Panama. Specifically, we use classic colour analysis to estimate variation in the number and the relative area of different colour spots across low predation sites in the introduced Panamanian range of the species. We then compare this variation to that found in the native range of the species under low- and high predation regimes. We found aspects of the colour pattern that were both consistent and inconsistent with the classical paradigm of colour evolution in guppies. On one hand, the same colours that dominated in native populations (orange, iridescent and black) were also the most dominant in the introduced populations in Panama. On the other, there were no clear differences between either introduced-low and native low- and high predation populations. Our results are therefore only partially consistent with the traditional role of female preference in the absence of predators, and suggest that additional factors could influence colour patterns when populations are removed from their native environments. Future research on the interaction between female preference and environmental variability (e.g. multifarious selection), could help understand adaptive variation in this widely-introduced species, and the contexts under which variation in adaptive traits parallels (or not) variation in the native range.

The clustering of galaxies in the SDSS-III DR10 Baryon Oscillation Spectroscopic Survey: no detectable colour dependence of distance scale or growth rate measurements

NASA Astrophysics Data System (ADS)

Ross, Ashley J.; Samushia, Lado; Burden, Angela; Percival, Will J.; Tojeiro, Rita; Manera, Marc; Beutler, Florian; Brinkmann, J.; Brownstein, Joel R.; Carnero, Aurelio; da Costa, Luiz A. N.; Eisenstein, Daniel J.; Guo, Hong; Ho, Shirley; Maia, Marcio A. G.; Montesano, Francesco; Muna, Demitri; Nichol, Robert C.; Nuza, Sebastián E.; Sánchez, Ariel G.; Schneider, Donald P.; Skibba, Ramin A.; Sobreira, Flávia; Streblyanska, Alina; Swanson, Molly E. C.; Thomas, Daniel; Tinker, Jeremy L.; Wake, David A.; Zehavi, Idit; Zhao, Gong-bo

2014-01-01

We study the clustering of galaxies, as a function of their colour, from Data Release Ten (DR10) of the Sloan Digital Sky Survey III (SDSS-III) Baryon Oscillation Spectroscopic Survey. DR10 contains 540 505 galaxies with 0.43 < z < 0.7; from these we select 122 967 for a `Blue' sample and 131 969 for a `Red' sample based on k + e corrected (to z = 0.55) r - i colours and i-band magnitudes. The samples are chosen such that both contain more than 100 000 galaxies, have similar redshift distributions and maximize the difference in clustering amplitude. The Red sample has a 40 per cent larger bias than the Blue (bRed/bBlue = 1.39 ± 0.04), implying that the Red galaxies occupy dark matter haloes with an average mass that is 0.5 log10 M⊙ greater. Spherically averaged measurements of the correlation function, ξ0, and the power spectrum are used to locate the position of the baryon acoustic oscillation (BAO) feature of both samples. Using ξ0, we obtain distance scales, relative to the distance of our reference Λ cold dark matter cosmology, of 1.010 ± 0.027 for the Red sample and 1.005 ± 0.031 for the Blue. After applying reconstruction, these measurements improve to 1.013 ± 0.020 for the Red sample and 1.008 ± 0.026 for the Blue. For each sample, measurements of ξ0 and the second multipole moment, ξ2, of the anisotropic correlation function are used to determine the rate of structure growth, parametrized by fσ8. We find fσ8, Red = 0.511 ± 0.083, fσ8, Blue = 0.509 ± 0.085 and fσ8, Cross = 0.423 ± 0.061 (from the cross-correlation between the Red and Blue samples). We use the covariance between the bias and growth measurements obtained from each sample and their cross-correlation to produce an optimally combined measurement of fσ8, comb = 0.443 ± 0.055. This result compares favourably to that of the full 0.43 < z < 0.7 sample (fσ8, full = 0.422 ± 0.051) despite the fact that, in total, we use less than half of the number of galaxies analysed in the full sample measurement. In no instance do we detect significant differences in distance scale or structure growth measurements obtained from the Blue and Red samples. Our results are consistent with theoretical predictions and our tests on mock samples, which predict that any colour-dependent systematic uncertainty on the measured BAO position is less than 0.5 per cent.

Processing speed can monitor stimulant-medication effects in adults with attention deficit disorder with hyperactivity.

PubMed

Nielsen, Niels Peter; Wiig, Elisabeth H; Bäck, Svante; Gustafsson, Jan

2017-05-01

Treatment responses to methylphenidate by adults with ADHD are generally monitored against DSM-IV/DSM-V symptomatology, rating scales or interviews during reviews. To evaluate the use of single- and dual-dimension processing-speed and efficiency measures to monitor the effects of pharmacological treatment with methylphenidate after a short period off medication. A Quick Test of Cognitive Speed (AQT) monitored the effects of immediate-release methylphenidate in 40 previously diagnosed and medicated adults with ADHD. Processing speed was evaluated with prior prescription medication, without medication after a 2-day period off ADHD medication, and with low-dose (10/20 mg) and high-dose (20/40 mg) methylphenidate hydrochloride (Medikinet IR). Thirty-three participants responded to the experimental treatments. One-way ANOVA with post-hoc analysis (Scheffe) indicated significant main effects for single dimension colour and form and dual-dimension colour-form naming. Post-hoc analysis indicated statistical differences between the no- and high-dose medication conditions for colour and form, measures of perceptual speed. For colour-form naming, a measure of cognitive speed, there was a significant difference between no- and low-dose medication and between no- and high-dose medications, but not between low- and high-dose medications. Results indicated that the AQT tests effectively monitored incremental effects of the methylphenidate dose on processing speed after a 2-day period off medication. Thus, perceptual (colour and form) and cognitive speed (two-dimensional colour-form naming) and processing efficiency (lowered shift costs) increased measurably with high-dose medication. These preliminary findings warrant validation with added measures of associated behavioural and cognitive changes.

Seed colour affects light and temperature requirements during germination in two Lotus species (Fabaceae) of the Arabian subtropical deserts.

PubMed

Bhatt, Arvind; Gairola, Sanjay; El-Keblawy, Ali A

2016-06-01

Heterogeneity in seeds mostly occurs due to physiological, environmental and genetic factors, and these could affect seed dormancy and germination. Therefore, the aim of our study was to assess the effect of seed colour on germination behavior. For this, both light and temperature requirements were assessed in Lotus glinoides and Lotus halophilus (Fabaceae) from the hyper-arid deserts of the United Arab Emirates. Germination was assessed in terms of both final germination level (percentage) and germination rate, as expressed by Timson’s germination velocity index. Lotus glinoides produces black and yellow-colored seeds, and L. halophilus produces green and yellow seeds. Different seed lots were germinated in both light and darkness at different temperatures. Yellow seeds of the two species attained significantly lower germination, compared to black and green seeds. There was no specific light or temperature requirements for the germination of the two coloured seeds of L. glinoides; the effect of interactions between seed colour and both light and incubation temperature, were not significant on the final germination percentage. In L. halophilus, green seeds germinated significantly more in both light and darkness at lower temperatures (15/25 °C) and in light at higher temperatures (25/35 °C), compared to yellow seeds. Yellow seeds germinated faster, compared to black at 15/25 °C in L. glinoides and compared to green seeds at 15/25 °C and 25/35 °C in L. halophilus. Seed colour variation, at least in L. halophilus, could be a survival strategy that would determine the time of germination throughout the year in the unpredictable desert environment.

Investment in testes, sperm-duct glands and lipid reserves differs between male morphs but not between early and late breeding season in Pomatoschistus minutus.

PubMed

Kvarnemo, C; Svensson, O; Manson, W

2010-05-01

This study of the sand goby Pomatoschistus minutus, a nest-holding fish with paternal care, focused on gonadal investment among males of different sizes collected early and late in the breeding season. All males caught at the nest had breeding colour, whereas trawl-caught fish consisted of males both with and without colour. The absence or presence of breeding colour was a good predictor of testes investment. Compared to males with breeding colour, males without colour were smaller in body size but had extraordinarily large testes. In absolute terms, testes mass of males without breeding colour was on average 3.4 times greater than those of males with breeding colour. Since small colourless males are known to reproduce as sneaker males, this heavy investment in testes probably reflects that they are forced to spawn under sperm competition. Contrary to testes size, sperm-duct glands were largest among males with breeding colour. These glands produce mucins used for making sperm-containing mucous trails that males place in the nest before and during spawning. Since both sneakers and nest-holders potentially could benefit from having large glands, this result is intriguing. Yet, high mucus production may be more important for nest-holders, because it also protects developing embryos from infections. There was no significant effect of season on body size, testes or sperm-duct glands size, but colourless males tended to be less common late in the season. Possibly this may indicate that individual small colourless males develop into their more colourful counterparts within the breeding season.

Red Reveals Branch Die-back in Norway Maple Acer platanoides

PubMed Central

Sinkkonen, Aki

2008-01-01

Background and Aims Physiological data suggest that autumn leaf colours of deciduous trees are adaptations to environmental stress. Recently, the evolution of autumn colouration has been linked to tree condition and defence. Most current hypotheses presume that autumn colours vary between tree individuals. This study was designed to test if within-tree variation should be taken into account in experimental and theoretical research on autumn colouration. Methods Distribution of red autumn leaf colours was compared between partially dead and vigorous specimens of Norway maple (Acer platanoides) in a 3-year study. In August, the amount of reddish foliage was estimated in pairs of partially dead and control trees. Within-tree variation in the distribution of reddish leaves was evaluated. Leaf nitrogen and carbon concentrations were analysed. Key Results Reddish leaf colours were more frequent in partially dead trees than in control trees. Reddish leaves were evenly distributed in control trees, while patchiness of red leaf pigments was pronounced in partially dead trees. Large patches of red leaves were found beneath or next to dead tree parts. These patches reoccurred every year. Leaf nitrogen concentration was lower in reddish than in green leaves but the phenomenon seemed similar in both partially dead and control trees. Conclusions The results suggest that red leaf colouration and branch condition are interrelated in Norway maple. Early reddish colours may be used as an indication of leaf nitrogen and carbon levels but not as an indication of tree condition. Studies that concentrate on entire trees may not operate at an optimal level to detect the evolutionary mechanisms behind autumnal leaf colour variation. PMID:18567914

Red reveals branch die-back in Norway maple Acer platanoides.

PubMed

Sinkkonen, Aki

2008-09-01

Physiological data suggest that autumn leaf colours of deciduous trees are adaptations to environmental stress. Recently, the evolution of autumn colouration has been linked to tree condition and defence. Most current hypotheses presume that autumn colours vary between tree individuals. This study was designed to test if within-tree variation should be taken into account in experimental and theoretical research on autumn colouration. Distribution of red autumn leaf colours was compared between partially dead and vigorous specimens of Norway maple (Acer platanoides) in a 3-year study. In August, the amount of reddish foliage was estimated in pairs of partially dead and control trees. Within-tree variation in the distribution of reddish leaves was evaluated. Leaf nitrogen and carbon concentrations were analysed. Reddish leaf colours were more frequent in partially dead trees than in control trees. Reddish leaves were evenly distributed in control trees, while patchiness of red leaf pigments was pronounced in partially dead trees. Large patches of red leaves were found beneath or next to dead tree parts. These patches reoccurred every year. Leaf nitrogen concentration was lower in reddish than in green leaves but the phenomenon seemed similar in both partially dead and control trees. The results suggest that red leaf colouration and branch condition are interrelated in Norway maple. Early reddish colours may be used as an indication of leaf nitrogen and carbon levels but not as an indication of tree condition. Studies that concentrate on entire trees may not operate at an optimal level to detect the evolutionary mechanisms behind autumnal leaf colour variation.

Chromatic Illumination Discrimination Ability Reveals that Human Colour Constancy Is Optimised for Blue Daylight Illuminations

PubMed Central

Pearce, Bradley; Crichton, Stuart; Mackiewicz, Michal; Finlayson, Graham D.; Hurlbert, Anya

2014-01-01

The phenomenon of colour constancy in human visual perception keeps surface colours constant, despite changes in their reflected light due to changing illumination. Although colour constancy has evolved under a constrained subset of illuminations, it is unknown whether its underlying mechanisms, thought to involve multiple components from retina to cortex, are optimised for particular environmental variations. Here we demonstrate a new method for investigating colour constancy using illumination matching in real scenes which, unlike previous methods using surface matching and simulated scenes, allows testing of multiple, real illuminations. We use real scenes consisting of solid familiar or unfamiliar objects against uniform or variegated backgrounds and compare discrimination performance for typical illuminations from the daylight chromaticity locus (approximately blue-yellow) and atypical spectra from an orthogonal locus (approximately red-green, at correlated colour temperature 6700 K), all produced in real time by a 10-channel LED illuminator. We find that discrimination of illumination changes is poorer along the daylight locus than the atypical locus, and is poorest particularly for bluer illumination changes, demonstrating conversely that surface colour constancy is best for blue daylight illuminations. Illumination discrimination is also enhanced, and therefore colour constancy diminished, for uniform backgrounds, irrespective of the object type. These results are not explained by statistical properties of the scene signal changes at the retinal level. We conclude that high-level mechanisms of colour constancy are biased for the blue daylight illuminations and variegated backgrounds to which the human visual system has typically been exposed. PMID:24586299

Biological decolourisation of wastewater from molasses fermentation by Trametes versicolor in an airlift reactor.

PubMed

Rioja, R; García, M T; Peña, M; González, G

2008-06-01

Continuous decolourisation of wastewater from molasses fermentation using mycelium of Trametes versicolor in pellets shape was performed in an airlift bioreactor (semi-pilot scale) with the aim of operating steadily for a long period, maintaining the colour removal activity. The influences of influent flow and glucose feed rate were tested. Induction of peroxidases secretion by Mn(2+) addition was also studied. The efficiency of the decolourisation process was followed by monitoring colour and enzymatic activities. The experimental results showed that continuous decolourisation in an airlift bioreactor can be considered a suitable alternative for treating molasses fermentation wastewater. A colour removal yield around 60% remained practically constant during 23 days under continuous operation. Laccase was found to be the main enzyme secreted by the strain, being responsible for the decolourisation process. Mn(2+) addition was not likely to induct manganese-dependent peroxidase secretion.

A colour-tunable, weavable fibre-shaped polymer light-emitting electrochemical cell

NASA Astrophysics Data System (ADS)

Zhang, Zhitao; Guo, Kunping; Li, Yiming; Li, Xueyi; Guan, Guozhen; Li, Houpu; Luo, Yongfeng; Zhao, Fangyuan; Zhang, Qi; Wei, Bin; Pei, Qibing; Peng, Huisheng

2015-04-01

The emergence of wearable electronics and optoelectronics requires the development of devices that are not only highly flexible but can also be woven into textiles to offer a truly integrated solution. Here, we report a colour-tunable, weavable fibre-shaped polymer light-emitting electrochemical cell (PLEC). The fibre-shaped PLEC is fabricated using all-solution-based processes that can be scaled up for practical applications. The design has a coaxial structure comprising a modified metal wire cathode and a conducting aligned carbon nanotube sheet anode, with an electroluminescent polymer layer sandwiched between them. The fibre shape offers unique and promising advantages. For example, the luminance is independent of viewing angle, the fibre-shaped PLEC can provide a variety of different and tunable colours, it is lightweight, flexible and wearable, and it can potentially be woven into light-emitting clothes for the creation of smart fabrics.

Adaptive introgression across species boundaries in Heliconius butterflies.

PubMed

Pardo-Diaz, Carolina; Salazar, Camilo; Baxter, Simon W; Merot, Claire; Figueiredo-Ready, Wilsea; Joron, Mathieu; McMillan, W Owen; Jiggins, Chris D

2012-01-01

It is widely documented that hybridisation occurs between many closely related species, but the importance of introgression in adaptive evolution remains unclear, especially in animals. Here, we have examined the role of introgressive hybridisation in transferring adaptations between mimetic Heliconius butterflies, taking advantage of the recent identification of a gene regulating red wing patterns in this genus. By sequencing regions both linked and unlinked to the red colour locus, we found a region that displays an almost perfect genotype by phenotype association across four species, H. melpomene, H. cydno, H. timareta, and H. heurippa. This particular segment is located 70 kb downstream of the red colour specification gene optix, and coalescent analysis indicates repeated introgression of adaptive alleles from H. melpomene into the H. cydno species clade. Our analytical methods complement recent genome scale data for the same region and suggest adaptive introgression has a crucial role in generating adaptive wing colour diversity in this group of butterflies.

Mapping stellar content to dark matter haloes - III. Environmental dependence and conformity of galaxy colours

NASA Astrophysics Data System (ADS)

Zu, Ying; Mandelbaum, Rachel

2018-05-01

Recent studies suggest that the quenching properties of galaxies are correlated over several megaparsecs. The large-scale `galactic conformity' phenomenon around central galaxies has been regarded as a potential signature of `galaxy assembly bias' or `pre-heating', both of which interpret conformity as a result of direct environmental effects acting on galaxy formation. Building on the iHOD halo quenching framework developed in Zu and Mandelbaum, we discover that our fiducial halo mass quenching model, without any galaxy assembly bias, can successfully explain the overall environmental dependence and the conformity of galaxy colours in Sloan Digital Sky Survey, as measured by the mark correlation functions of galaxy colours and the red galaxy fractions around isolated primaries, respectively. Our fiducial iHOD halo quenching mock also correctly predicts the differences in the spatial clustering and galaxy-galaxy lensing signals between the more versus less red galaxy subsamples, split by the red-sequence ridge line at fixed stellar mass. Meanwhile, models that tie galaxy colours fully or partially to halo assembly bias have difficulties in matching all these observables simultaneously. Therefore, we demonstrate that the observed environmental dependence of galaxy colours can be naturally explained by the combination of (1) halo quenching and (2) the variation of halo mass function with environment - an indirect environmental effect mediated by two separate physical processes.

Neutral processes contribute to patterns of spatial variation for flower colour in the Mediterranean Iris lutescens (Iridaceae)

PubMed Central

Wang, Hui; Talavera, María; Min, Ya; Flaven, Elodie; Imbert, Eric

2016-01-01

Background and Aims Flower colour polymorphism in plants has been used as a classic model for understanding the importance of neutral processes vs. natural selection in population differentiation. However, current explanations for the maintenance of flower colour polymorphism mainly rely on balancing selection, while neutral processes have seldom been championed. Iris lutescens (Iridaceae) is a widespread species in the northern Mediterranean basin, which shows a stable and striking purple–yellow flower colour polymorphism. To evaluate the roles of neutral processes in the spatial variation for flower colour in this species, patterns of neutral genetic variation across its distribution range were quantified, and phenotypic differentiation was compared with neutral genetic differentiation. Methods Genetic diversity levels and population genetic structure were investigated through the genotyping of a collection of 1120 individuals in 41 populations ranging from Spain to France, using a set of eight newly developed microsatellite markers. In addition, phenotypic differentiation for flower colour was also quantified by counting colour morph frequency in each population, and measuring the reflectance spectra of sampled individuals. Key Results Populations in Spain present a sharp colour transition from solely purple to solely yellow. The results provide evidence that genetic drift through limited gene flow is important in the evolution of monomorphic populations. In contrast, most populations in France are polymorphic with both phenotypes, and the colour frequencies vary geographically without any spatial gradients observed. A pattern of isolation by distance is detected in France, and gene flow between adjacent populations seems to be an important factor maintaining populations polymorphic. Conclusions Overall, neutral processes contribute to patterns of spatial variation for flower colour in I. lutescens, but it cannot be excluded that natural selection is also operating. An interaction between neutral processes and natural selection is suggested to explain the spatial variation for flower colour in I. lutescens. PMID:27084922

Neutral processes contribute to patterns of spatial variation for flower colour in the Mediterranean Iris lutescens (Iridaceae).

PubMed

Wang, Hui; Talavera, María; Min, Ya; Flaven, Elodie; Imbert, Eric

2016-05-01

Flower colour polymorphism in plants has been used as a classic model for understanding the importance of neutral processes vs. natural selection in population differentiation. However, current explanations for the maintenance of flower colour polymorphism mainly rely on balancing selection, while neutral processes have seldom been championed. Iris lutescens (Iridaceae) is a widespread species in the northern Mediterranean basin, which shows a stable and striking purple-yellow flower colour polymorphism. To evaluate the roles of neutral processes in the spatial variation for flower colour in this species, patterns of neutral genetic variation across its distribution range were quantified, and phenotypic differentiation was compared with neutral genetic differentiation. Genetic diversity levels and population genetic structure were investigated through the genotyping of a collection of 1120 individuals in 41 populations ranging from Spain to France, using a set of eight newly developed microsatellite markers. In addition, phenotypic differentiation for flower colour was also quantified by counting colour morph frequency in each population, and measuring the reflectance spectra of sampled individuals. Populations in Spain present a sharp colour transition from solely purple to solely yellow. The results provide evidence that genetic drift through limited gene flow is important in the evolution of monomorphic populations. In contrast, most populations in France are polymorphic with both phenotypes, and the colour frequencies vary geographically without any spatial gradients observed. A pattern of isolation by distance is detected in France, and gene flow between adjacent populations seems to be an important factor maintaining populations polymorphic. Overall, neutral processes contribute to patterns of spatial variation for flower colour in I. lutescens, but it cannot be excluded that natural selection is also operating. An interaction between neutral processes and natural selection is suggested to explain the spatial variation for flower colour in I. lutescens. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

A novel framework for the use of remote sensing for monitoring catchments at continental scales.

PubMed

Bugnot, A B; Lyons, M B; Scanes, P; Clark, G F; Fyfe, S K; Lewis, A; Johnston, E L

2018-07-01

Historical ecology can teach us valuable lessons on the processes and drivers of environmental change that can inform future monitoring priorities and management strategies. Environmental data to study environmental history, however, is often absent or of low quality. Even when studying changes occurring during the last few decades, monitoring efforts are scarce due to logistical and cost limitations, leaving large areas unassessed. The aim of this study is to evaluate the use of estuarine water colour as an indicator of historical environmental change in catchments. Water colour change was assessed in estuaries in Australia from 1987 to 2015 using satellite remote sensing. Random points were selected for each estuary and applied to the Australian Geoscience Data Cube (based on Landsat images) to obtain reflectance data through time. We propose a framework where (i) water colour is used to detect historical changes in catchments using generalised additive models, (ii) possible stressors and pressures driving those changes are evaluated using other available historical data, and (iii) lessons learned inform appropriate monitoring and management actions. This framework represents a novel approach to generate historical data for large-scale assessments of environmental change at catchment level, even in poorly studied areas. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Investigating the impact of age-depended hair colour darkening during childhood on DNA-based hair colour prediction with the HIrisPlex system.

PubMed

Kukla-Bartoszek, Magdalena; Pośpiech, Ewelina; Spólnicka, Magdalena; Karłowska-Pik, Joanna; Strapagiel, Dominik; Żądzińska, Elżbieta; Rosset, Iwona; Sobalska-Kwapis, Marta; Słomka, Marcin; Walsh, Susan; Kayser, Manfred; Sitek, Aneta; Branicki, Wojciech

2018-06-06

Predictive DNA analysis of externally visible characteristics exerts an increasing influence on contemporary forensic and anthropological investigations, with pigmentation traits currently being the most advanced for predictive modelling. Since pigmentation prediction error in some cases may be due to the result of age-related hair colour darkening, and sex influence in eye colour, this study aims to investigate these less explored phenomena on a group of juvenile individuals. Pigmentation phenotypes of children between the age of 6-13 years old were evaluated, in addition to data about their hair colour during early childhood from a select number of these individuals. The HIrisPlex models for DNA-based eye and hair colour prediction were used with input from SNP genotyping using massive parallel sequencing. Analysis of the total group of 476 children showed high accuracy in blue (AUC = 0.89) and brown (AUC = 0.91) eye colour prediction, while hair colour was predicted with AUC = 0.64 for blond, AUC = 0.64 for brown and AUC = 0.97 for red. 70.8% (n = 143) of the total number of children phenotypically blond for hair colour during early childhood progressed to brown during advanced childhood. In 70.6% (n = 101) of those cases, an incorrect blond hair prediction was made during the time of analysis. A noticeable decline in AUC values for blond (from 0.76 to 0.65) and brown (from 0.72 to 0.64) were observed when comparing hair colour prediction outcomes for the phenotypes recorded for the two different time points (at the age of 2-3 and 6-13). The number of incorrect blond hair colour predictions was significantly higher in children with brown hair at age 6-13 who were blond at early childhood (n = 47, 32.9%), relative to children who had brown hair at both time points (n = 6, 9.4%). However, in 28.0% (n = 40) of children who did experience hair colour darkening, HIrisPlex provided the correct prediction for the darkened hair colour phenotype, despite them being blond in early childhood. Our study implies that HIrisPlex can correctly predict adult hair colour in some individuals who experience age-related hair colour darkening during adolescence. However, in most instances prediction seems to default to the pre-adolescent hair colour for individuals with this phenomenon. In the future, the full adolescent age range in which hair colour darkening can occur should be considered in the study samples used for training hair colour prediction models to obtain a more complete picture of the phenomenon and its impact on DNA-based hair colour prediction in adults. Copyright © 2018 Elsevier B.V. All rights reserved.

The well-tuned blues: the role of structural colours as optical signals in the species recognition of a local butterfly fauna (Lepidoptera: Lycaenidae: Polyommatinae)

PubMed Central

Bálint, Zsolt; Kertész, Krisztián; Piszter, Gábor; Vértesy, Zofia; Biró, László P.

2012-01-01

The photonic nanoarchitectures responsible for the blue colour of the males of nine polyommatine butterfly species living in the same site were investigated structurally by electron microscopy and spectrally by reflectance spectroscopy. Optical characterization was carried out on 110 exemplars. The structural data extracted by dedicated software and the spectral data extracted by standard software were inputted into an artificial neural network software to test the specificity of the structural and optical characteristics. It was found that both the structural and the spectral data allow species identification with an accuracy better than 90 per cent. The reflectance data were further analysed using a colour representation diagram built in a manner analogous to that of the human Commission Internationale de l'Eclairage diagram, but the additional blue visual pigment of lycaenid butterflies was taken into account. It was found that this butterfly-specific colour representation diagram yielded a much clearer distinction of the position of the investigated species compared with previous calculations using the human colour space. The specific colours of the investigated species were correlated with the 285 flight-period data points extracted from museum collections. The species with somewhat similar colours fly in distinct periods of the year such that the blue colours are well tuned for safe mate/competitor recognition. This allows for the creation of an effective pre-zygotic isolation mechanism for closely related synchronic and syntopic species. PMID:22319114

A Matter of Contrast: Yellow Flower Colour Constrains Style Length in Crocus species.

PubMed

Lunau, Klaus; Konzmann, Sabine; Bossems, Jessica; Harpke, Doerte

2016-01-01

Most flowers display distinct colour patterns comprising two different areas. The peripheral large-area component of floral colour patterns attracts flower visitors from some distance and the central small-area component guides flower visitors towards landing sites. Whereas the peripheral colour is largely variable among species, the central colour, produced mostly by anthers and pollen or pollen mimicking floral guides, is predominantly yellow and UV-absorbing. This holds also for yellow flowers that regularly display a UV bull's eye pattern. Here we show that yellow-flowering Crocus species are a noticeable exception, since yellow-flowering Crocus species-being entirely UV-absorbing-exhibit low colour contrast between yellow reproductive organs and yellow tepals. The elongated yellow or orange-yellow style of Crocus flowers is a stamen-mimicking structure promoting cross-pollination by facilitating flower visitors' contact with the apical stigma before the flower visitors are touching the anthers. Since Crocus species possess either yellow, violet or white tepals, the colour contrast between the stamen-mimicking style and the tepals varies among species. In this study comprising 106 Crocus species, it was tested whether the style length of Crocus flowers is dependent on the corolla colour. The results show that members of the genus Crocus with yellow tepals have evolved independently up to twelve times in the genus Crocus and that yellow-flowering Crocus species possess shorter styles as compared to violet- and white-flowering ones. The manipulation of flower visitors by anther-mimicking elongated styles in Crocus flowers is discussed.

The use of an ordinary colour scanner to fingerprint sediment sources in the South African Karoo.

PubMed

Pulley, Simon; Rowntree, Kate

2016-01-01

The widespread adoption of sediment fingerprinting methodologies for the purpose of catchment management has been restricted by the high cost of tracer analysis as well as the potential for significant uncertainties to be present in results. Sediment colour has shown potential to be an inexpensive tracer able to discriminate between sediment sources. However, at present colour has not been demonstrated to be conservative during sediment erosion and transport. Sediment particle size and organic matter have been shown to strongly affect sediment colour, introducing significant uncertainties associated with its use. This study aimed to assess the suitability of colour as a tracer when it is measured using a commercially available colour scanner. The use of hydrogen peroxide (H2O2) to decompose sediment-associated organic matter was assessed as a means of minimising uncertainty. The impact of particle size on the accurate use of colour signatures as a tracer was also assessed. It was concluded that colour performed comparably to mineral magnetic signatures and showed good potential for use as a tracer. The use of H2O2 pre-treatment and limitation of the analysis to either the <32 μm or the >32 μm fraction of the samples were indicated to be important methods to limit uncertainties associated with organic matter and particle size. The methods used were considerably more time and cost effective than the measurement of most conventional tracers. Copyright © 2015 Elsevier Ltd. All rights reserved.

Colour vision and light sensitivity in tunnel workers previously exposed to acrylamide and N-methylolacrylamide containing grouting agents.

PubMed

Goffeng, Lars Ole; Kjuus, Helge; Heier, Mona Skard; Alvestrand, Monica; Ulvestad, Bente; Skaug, Vidar

2008-01-01

The aim of the study was to examine possible persisting visual system effects in tunnel workers previously exposed to acrylamide and N-methylolacrylamide during grouting work. Visual field light sensitivity threshold and colour vision has been examined among 44 tunnel workers 2-10 years after exposure to acrylamide and N-methylolacrylamide containing grouting agents. Forty-four tunnel workers not involved in grouting operations served as control group. Information on exposure and background variables was obtained for all participants from a questionnaire. Visual light sensitivity threshold was measured using Humphrey Visual Field Static Perimeter 740, program 30-2 Fastpack, with red stimuli on white background, and colour vision, using Lanthony D-15 Desaturated Color test. Based on D-15d test results, colour confusion index (CCI), and a severity index (C-index) was calculated. The exposed group had a significantly higher threshold for detecting single stimuli in all parts of the inner 30 degrees of the visual field compared to the control group. The foveal threshold group difference was 1.4 dB (p=0.002) (mean value, both eyes). On the Lanthony 15 Hue Desaturated test, the exposed subjects made more errors in sorting blue colours, and a statistically significant increase in C-index was observed. Surrogate measures for duration and intensity of exposure gave no further improvement of the model. The results indicate slightly reduced light sensitivity and reduced colour discrimination among the exposed subjects compared to the controls. The findings may be due to previous exposure to acrylamide containing grouts among the tunnel workers.

Colour of fat, and colour, fatty acid composition and sensory characteristics of muscle from heifers offered alternative forages to grass silage in a finishing ration.

PubMed

Moloney, A P; Mooney, M T; Kerry, J P; Stanton, C; O'Kiely, P

2013-11-01

The effect of type of silage offered to beef heifers during the finishing period on aspects of beef quality was determined. In two experiments, a diet based on grass silage (GS) was compared with a diet based on maize silage (MS) or whole-crop wheat silage (WCW). Compared to the GS-based diet, increasing the amount of MS linearly increased fat whiteness while the increase in fat whiteness due to WCW was dependent on the stage of crop maturity at harvesting. There was no effect of diet on muscle colour or on muscle pH measured at 48h post-mortem, drip loss, taste panel traits after 14days ageing or shear force values at 2, 7 or 14days ageing. The alternative silages decreased the n-3 polyunsaturated fatty acid proportion and increased the linoleic:linolenic acid ratio in intramuscular lipid. It is concluded that type of silage affects fat colour and fatty acid composition of muscle but not the other muscle characteristics examined. Copyright © 2013 Elsevier Ltd. All rights reserved.

Crowdsourcing as an Analytical Method: Metrology of Smartphone Measurements in Heritage Science.

PubMed

Brigham, Rosie; Grau-Bové, Josep; Rudnicka, Anna; Cassar, May; Strlic, Matija

2018-06-18

This research assesses the precision, repeatability, and accuracy of crowdsourced scientific measurements, and whether their quality is sufficient to provide usable results. Measurements of colour and area were chosen because of the possibility of producing them with smartphone cameras. The quality of the measurements was estimated experimentally by comparing data contributed by anonymous participants in heritage sites with reference measurements of known accuracy and precision. Participants performed the measurements by taking photographs with their smartphones, from which colour and dimensional data could be extracted. The results indicate that smartphone measurements provided by citizen scientists can be used to measure changes in colour, but that the performance is strongly dependent on the measured colour coordinate. The same method can be used to measure areas when the difference in colour with the neighbouring areas is large enough. These results render the method useful in some heritage science contexts, but higher precision would be desirable. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

The intensity threshold of colour vision in a passerine bird, the blue tit (Cyanistes caeruleus).

PubMed

Gomez, Doris; Grégoire, Arnaud; Del Rey Granado, Maria; Bassoul, Marine; Degueldre, David; Perret, Philippe; Doutrelant, Claire

2014-11-01

Many vertebrates use colour vision for vital behaviour but their visual performance in dim light is largely unknown. The light intensity threshold of colour vision is known only for humans, horses and two parrot species. Here, we first explore this threshold in a passerine bird, the blue tit (Cyanistes caeruleus). Using classic conditioning of colour cues to food rewards in three individuals, we find a threshold ranging from 0.05 to 0.2 cd m(-2). Results are comparable to the two previously tested bird species. For tits, nest light conditions probably exceed that threshold, at least after sunrise. These results shed new light on the lively debate questioning the visual performance of cavity nesters and the evolutionary significance of egg and chick coloration. Although this needs further investigation, it is possible that blue tits exploit both colour and brightness cues when viewing their eggs, chicks or conspecifics in their nests. © 2014. Published by The Company of Biologists Ltd.

'Behind blue eyes'†: the association between eye colour and deep infiltrating endometriosis.

PubMed

Vercellini, Paolo; Buggio, Laura; Somigliana, Edgardo; Dridi, Dhouha; Marchese, Maria Antonietta; Viganò, Paola

2014-10-10

Is the prevalence of blue eye colour higher in women with deep endometriosis? Blue eye colour is more common in women with deep endometriosis when compared with both women with ovarian endometriomas and women without a history of endometriosis. Recent and intriguing evidence suggests that women with deep endometriosis may have particular phenotypic characteristics including a higher prevalence of a light-colour iris. Available epidemiological evidence is however weak. Case-control study performed in a large academic department specializing in the study and treatment of endometriosis. Individual iris colour was evaluated in daylight and categorized in three grades, namely blue-grey (blue), hazel-green (green) and brown. One observer assessed iris colour. In addition, the women themselves were invited to indicate the colour of their eyes according to the same classification system. Cases with discordant eye colour determinations between the observer and the woman were excluded from the final analysis. Two hundred and twenty-three women with deep endometriosis (cases), 247 with ovarian endometriomas and 301 without a history of endometriosis were enrolled. After exclusion of 52 discordant cases, the proportions of brown, blue and green eye colours were, respectively, 61, 30 and 9% in the deep endometriosis group, 74, 16 and 10% in the endometrioma group and 75, 15 and 10% in the non-endometriosis group. Women in the deep endometriosis group had a statistically significant excess of blue eyes and a reduced proportion of brown eyes compared with the two control groups (P = 0.002 and P < 0.001, respectively). The proportion of blue eyes was almost identical in the ovarian endometrioma group and the non-endometriosis group, and that of green eyes was substantially similar in all study groups. The OR (95% CI) of having blue eyes in women with deep endometriosis compared with women with ovarian endometriosis and with those without endometriosis was, respectively, 2.2 (1.4-3.6) and 2.5 (1.6-3.9). We cannot exclude that some women without a previous diagnosis of endometriosis indeed had the disease. However, this would have led to a reduction of the observed difference in proportion of blue eyes, thus to a potential underestimation of the real strength of the association. Moreover, under-ascertainment is possible with regard to peritoneal disease, but unlikely with deep endometriotic lesions and ovarian endometriomas. There are two possible explanations for our findings. Both may have intriguing implications for future research on endometriosis. Firstly, genes involved in the control of iris colour transmission may lie in a region with a strong pattern of linkage disequilibrium with genes involved in the invasiveness of endometriosis. Alternatively, blue eye colour could be considered an indicator of a photo-sensitive phenotype resulting in limited exposure to sunlight and UVB radiation. Limited sunlight exposure is associated with reduced circulating 25-hydroxyvitamin D3, an element that has recently been linked to endometriosis development. © The Author 2014. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

A 15-year global biogeochemical reanalysis with ocean colour data assimilation

NASA Astrophysics Data System (ADS)

Ford, David; Barciela, Rosa

2013-04-01

A continuous global time-series of remotely sensed ocean colour observations is available from 1997 to the present day. However coverage is incomplete, and limited to the sea surface. Models are therefore required to provide full spatial coverage, and to investigate the relationships between physical and biological variables and the carbon cycle. Data assimilation can then be used to constrain models to fit the observations, thereby combining the advantages of both sources of information. As part of the European Space Agency's Climate Change Initiative (ESA-CCI), we assimilate chlorophyll concentration derived from ocean colour observations into a coupled physical-biogeochemical model. The data assimilation scheme (Hemmings et al., 2008, J. Mar. Res.; Ford et al., 2012, Ocean Sci.) uses the information from the observations to update all biological and carbon cycle state variables within the model. Global daily reanalyses have been produced, with and without assimilation of merged ocean colour data provided by GlobColour, for the period September 1997 to August 2012. The assimilation has been shown to significantly improve the model's representation of chlorophyll concentration, at the surface and at depth. Furthermore, there is evidence of improvement to the representation of pCO2, nutrients and zooplankton concentration compared to in situ observations. We use the results to quantify recent seasonal and inter-annual variability in variables including chlorophyll concentration, air-sea CO2 flux and alkalinity. In particular, we explore the impact of physical drivers such as the El Niño Southern Oscillation (ENSO) on the model's representation of chlorophyll and the carbon cycle, and the pros and cons of the model reanalyses compared to observation-based climatologies. Furthermore, we perform a comparison between the GlobColour product and an initial version of a new merged product being developed as part of the ESA-CCI. Equivalent year-long hindcasts are performed with assimilation of each data set, and compared to a control run. Differences in the products are discussed, along with their impact on model accuracy compared to in situ observations, and the representation of the carbon cycle in each hindcast.

Improved image retrieval based on fuzzy colour feature vector

NASA Astrophysics Data System (ADS)

Ben-Ahmeida, Ahlam M.; Ben Sasi, Ahmed Y.

2013-03-01

One of Image indexing techniques is the Content-Based Image Retrieval which is an efficient way for retrieving images from the image database automatically based on their visual contents such as colour, texture, and shape. In this paper will be discuss how using content-based image retrieval (CBIR) method by colour feature extraction and similarity checking. By dividing the query image and all images in the database into pieces and extract the features of each part separately and comparing the corresponding portions in order to increase the accuracy in the retrieval. The proposed approach is based on the use of fuzzy sets, to overcome the problem of curse of dimensionality. The contribution of colour of each pixel is associated to all the bins in the histogram using fuzzy-set membership functions. As a result, the Fuzzy Colour Histogram (FCH), outperformed the Conventional Colour Histogram (CCH) in image retrieving, due to its speedy results, where were images represented as signatures that took less size of memory, depending on the number of divisions. The results also showed that FCH is less sensitive and more robust to brightness changes than the CCH with better retrieval recall values.

The dual rod system of amphibians supports colour discrimination at the absolute visual threshold

PubMed Central

Yovanovich, Carola A. M.; Koskela, Sanna M.; Nevala, Noora; Kondrashev, Sergei L.

2017-01-01

The presence of two spectrally different kinds of rod photoreceptors in amphibians has been hypothesized to enable purely rod-based colour vision at very low light levels. The hypothesis has never been properly tested, so we performed three behavioural experiments at different light intensities with toads (Bufo) and frogs (Rana) to determine the thresholds for colour discrimination. The thresholds of toads were different in mate choice and prey-catching tasks, suggesting that the differential sensitivities of different spectral cone types as well as task-specific factors set limits for the use of colour in these behavioural contexts. In neither task was there any indication of rod-based colour discrimination. By contrast, frogs performing phototactic jumping were able to distinguish blue from green light down to the absolute visual threshold, where vision relies only on rod signals. The remarkable sensitivity of this mechanism comparing signals from the two spectrally different rod types approaches theoretical limits set by photon fluctuations and intrinsic noise. Together, the results indicate that different pathways are involved in processing colour cues depending on the ecological relevance of this information for each task. This article is part of the themed issue ‘Vision in dim light’. PMID:28193811

The O-(Al2) centre in topaz and its relation to the blue colour

NASA Astrophysics Data System (ADS)

da Silva, D. N.; Guedes, K. J.; Pinheiro, M. V. B.; Schweizer, S.; Spaeth, J.-M.; Krambrock, K.

2005-01-01

Colour-enhanced blue topaz is one of the most traded gemstones. Naturally very rare, mostly topaz is irradiated by neutrons, electrons, gamma radiation and combinations of them. The colour centre is still not identified. It was speculated that it is related to a Si dangling bond defect occupied by two electrons with spin S = 0. We investigated natural blue as well as colourless topaz from different regions in Brazil by electron paramagnetic resonance (EPR), optical absorption and Raman spectroscopy. The results are compared with neutron and gamma-irradiated blue topaz. By EPR two paramagnetic defects are identified in all samples: (i) the peroxy radical (O2-) measured at room temperature and (ii) an (O-) hole centre interacting with two equivalent Al neighbours measured at low temperature. Blue samples show an absorption band centred at 620 nm which is responsible for the blue colour. From our investigation we find that the O-(Al2) hole centre has nearly the same thermal stability as the optical absorption band. However, we cannot say whether it is responsible for the absorption band and the blue colour. We suggest that at least it plays a dominant role in the stabilization of the blue colour.

Parallel inputs to memory in bee colour vision.

PubMed

Horridge, Adrian

2016-03-01

In the 19(th) century, it was found that attraction of bees to light was controlled by light intensity irrespective of colour, and a few critical entomologists inferred that vision of bees foraging on flowers was unlike human colour vision. Therefore, quite justly, Professor Carl von Hess concluded in his book on the Comparative Physiology of Vision (1912) that bees do not distinguish colours in the way that humans enjoy. Immediately, Karl von Frisch, an assistant in the Zoology Department of the same University of Münich, set to work to show that indeed bees have colour vision like humans, thereby initiating a new research tradition, and setting off a decade of controversy that ended only at the death of Hess in 1923. Until 1939, several researchers continued the tradition of trying to untangle the mechanism of bee vision by repeatedly testing trained bees, but made little progress, partly because von Frisch and his legacy dominated the scene. The theory of trichromatic colour vision further developed after three types of receptors sensitive to green, blue, and ultraviolet (UV), were demonstrated in 1964 in the bee. Then, until the end of the century, all data was interpreted in terms of trichromatic colour space. Anomalies were nothing new, but eventually after 1996 they led to the discovery that bees have a previously unknown type of colour vision based on a monochromatic measure and distribution of blue and measures of modulation in green and blue receptor pathways. Meanwhile, in the 20(th) century, search for a suitable rationalization, and explorations of sterile culs-de-sac had filled the literature of bee colour vision, but were based on the wrong theory.

Colour vision in AIDS patients without HIV retinopathy.

PubMed

Sommerhalder, J; Baglivo, E; Barbey, C; Hirschel, B; Roth, A; Pelizzone, M

1998-11-01

Patients suffering from AIDS develop ocular complications, the most frequent being HIV retinopathy. It is however not clear, if functional visual impairments can be observed as early indicators of ocular complications, before clinical diagnosis of HIV retinopathy is made at fundus examination. To address this issue, we measured colour vision in a group of 49 AIDS subjects with normal clinical fundi using the 'two equation method'. This method, combining red-green Rayleigh and the blue-green Moreland metameric matches, enables more complete and quantitative assessments of colour vision than those based on pigmentary tests. Data were collected on our computer controlled colorimeter and compared to those of normal subjects. While most AIDS subjects without HIV retinopathy demonstrated normal colour vision, a significant portion of them had wider matches than normal subjects (11% for the Rayleigh equation and 16% for the Moreland equation). Furthermore, matching ranges of the Moreland equation were significantly correlated with CD4 lymphocyte counts. Patients with low CD4 values tended to produce larger matching ranges than the patients with high CD4 values. A within subject study on 17 patients confirmed this trend and showed that the patients who increased/decreased their CD4 blood counts generally improved/impaired their colour discrimination in the Moreland match. No such correlation was found between the matching ranges of the Rayleigh equation and the CD4 counts. These results show that colour discrimination is slightly reduced in some AIDS subjects, although there are no detectable ocular complications. They also suggest two different types of colour vision impairments in AIDS patients without retinopathy: one reversible process affecting colour discrimination in the blue-green range; and another irreversible process affecting colour discrimination in the red-green range.

Ineffective crypsis in a crab spider: a prey community perspective

PubMed Central

Brechbühl, Rolf; Casas, Jérôme; Bacher, Sven

2010-01-01

Cryptic coloration is assumed to be beneficial to predators because of an increased encounter rate with unwary prey. This hypothesis is, however, very rarely, if ever, studied in the field. The aim of this study was to quantify the encounter rate and capture success of an ambush predator, in the field, as a function of its level of colour-matching with the background. We used the crab spider Misumena vatia, which varies its body colour and can thereby match the colour of the flower it hunts upon. We carried out a manipulative field experiment using a complete factorial design resulting in six different colour combinations of crab spiders and flowers differing in their degree of colour-matching. A rich and diverse set of naturally occurring insects visited the flowers while we continuously video-recorded the spider's foraging activity. This enabled us to test the crypsis, the spider avoidance and the flower visitor attraction hypotheses, all three supported by previous studies. Flower visitors of different groups either avoided crab spiders independent of colour-matching, such as solitary bees and syrphid flies, or ignored them, such as bumble-bees and honeybees. Moreover, colour-matched spiders did not have a higher encounter rate and capture success compared to the visually apparent ones. Thus, our results support the spider avoidance hypothesis, reject the two other hypotheses and uncovered a fourth behaviour: indifference to predators. Because flower visitors reacted differently, a community approach is mandatory in order to understand the function of background colour-matching in generalist predators. We discuss our results in relation to the size and sociality of the prey and in relation to the functional significance of colour change in this predator. PMID:19889699

Ineffective crypsis in a crab spider: a prey community perspective.

PubMed

Brechbühl, Rolf; Casas, Jérôme; Bacher, Sven

2010-03-07

Cryptic coloration is assumed to be beneficial to predators because of an increased encounter rate with unwary prey. This hypothesis is, however, very rarely, if ever, studied in the field. The aim of this study was to quantify the encounter rate and capture success of an ambush predator, in the field, as a function of its level of colour-matching with the background. We used the crab spider Misumena vatia, which varies its body colour and can thereby match the colour of the flower it hunts upon. We carried out a manipulative field experiment using a complete factorial design resulting in six different colour combinations of crab spiders and flowers differing in their degree of colour-matching. A rich and diverse set of naturally occurring insects visited the flowers while we continuously video-recorded the spider's foraging activity. This enabled us to test the crypsis, the spider avoidance and the flower visitor attraction hypotheses, all three supported by previous studies. Flower visitors of different groups either avoided crab spiders independent of colour-matching, such as solitary bees and syrphid flies, or ignored them, such as bumble-bees and honeybees. Moreover, colour-matched spiders did not have a higher encounter rate and capture success compared to the visually apparent ones. Thus, our results support the spider avoidance hypothesis, reject the two other hypotheses and uncovered a fourth behaviour: indifference to predators. Because flower visitors reacted differently, a community approach is mandatory in order to understand the function of background colour-matching in generalist predators. We discuss our results in relation to the size and sociality of the prey and in relation to the functional significance of colour change in this predator.

Analysis of the color rendition of flexible endoscopes

NASA Astrophysics Data System (ADS)

Murphy, Edward M.; Hegarty, Francis J.; McMahon, Barry P.; Boyle, Gerard

2003-03-01

Endoscopes are imaging devices routinely used for the diagnosis of disease within the human digestive tract. Light is transmitted into the body cavity via incoherent fibreoptic bundles and is controlled by a light feedback system. Fibreoptic endoscopes use coherent fibreoptic bundles to provide the clinician with an image. It is also possible to couple fibreoptic endoscopes to a clip-on video camera. Video endoscopes consist of a small CCD camera, which is inserted into gastrointestinal tract, and associated image processor to convert the signal to analogue RGB video signals. Images from both types of endoscope are displayed on standard video monitors. Diagnosis is dependent upon being able to determine changes in the structure and colour of tissues and biological fluids, and therefore is dependent upon the ability of the endoscope to reproduce the colour of these tissues and fluids with fidelity. This study investigates the colour reproduction of flexible optical and video endoscopes. Fibreoptic and video endoscopes alter image colour characteristics in different ways. The colour rendition of fibreoptic endoscopes was assessed by coupling them to a video camera and applying video colorimetric techniques. These techniques were then used on video endoscopes to assess how the colour rendition of video endoscopes compared with that of optical endoscopes. In both cases results were obtained at fixed illumination settings. Video endoscopes were then assessed with varying levels of illumination. Initial results show that at constant luminance endoscopy systems introduce non-linear shifts in colour. Techniques for examining how this colour shift varies with illumination intensity were developed and both methodology and results will be presented. We conclude that more rigorous quality assurance is required to reduce colour error and are developing calibration procedures applicable to medical endoscopes.

Water Discolouration Risk Mapping: a Regionally Mapped Model

NASA Astrophysics Data System (ADS)

Kirkby, M.; Arrell, K.; McDonald, A.; Tillotson, M.; Foulger, M.; Walker, A.

2006-12-01

Discolouration in catchment waters is caused by the release through oxidation, warming and biological decomposition of the soil. Catchments that yield highly discoloured waters not only increase treatment and sludge disposal costs but also risk compliance failures and increase the potential for Trihalomethane (THM) production; an unwanted byproduct of water chlorination. Therefore it is important for water companies to quantify and map water discolouration risk within their catchments to guide surveillance and intervention strategies. Yorkshire Water Services derives significant water resources from upland catchments. These catchments continue to produce increasing quantities of discolouration which are problematic and costly to treat. The company is taking several initiatives to manage colour. Traditional water colour studies tend to be restricted in scale and are unable to make conclusions about water colour production within a region. Sensitivities of water colour production to feedbacks and interactions between multiple factors also remains largely unquantified. This research addressed these limitations and mapped water discolouration risk for the Yorkshire Water area. Many factors are believed to influence colour production within a catchment. These are divided into two groups: dynamic factors for example, drought frequency, duration and severity or changes in the levels of acid precipitation; and static factors that are catchment specific, such as land management techniques, slope, soil type and erosion. A map of discolouration risk was created by sourcing and combining data for each of these variables. Data were categorised as either factors or constraints on water colour production and combined in a series of weighted overlays within a GIS, reflecting recent research on the processes leading to water colour production. Resulting risk maps identified a large variability in risk throughout study catchments. Analyses were also undertaken to examine the sensitivities of these distributions to changing land management techniques which will in turn inform Yorkshire Water of potential strategies towards the reduction of water discolouration.

Galaxy evolution in the metric of the cosmic web

NASA Astrophysics Data System (ADS)

Kraljic, K.; Arnouts, S.; Pichon, C.; Laigle, C.; de la Torre, S.; Vibert, D.; Cadiou, C.; Dubois, Y.; Treyer, M.; Schimd, C.; Codis, S.; de Lapparent, V.; Devriendt, J.; Hwang, H. S.; Le Borgne, D.; Malavasi, N.; Milliard, B.; Musso, M.; Pogosyan, D.; Alpaslan, M.; Bland-Hawthorn, J.; Wright, A. H.

2018-02-01

The role of the cosmic web in shaping galaxy properties is investigated in the Galaxy And Mass Assembly (GAMA) spectroscopic survey in the redshift range 0.03 ≤ z ≤ 0.25. The stellar mass, u - r dust corrected colour and specific star formation rate (sSFR) of galaxies are analysed as a function of their distances to the 3D cosmic web features, such as nodes, filaments and walls, as reconstructed by DisPerSE. Significant mass and type/colour gradients are found for the whole population, with more massive and/or passive galaxies being located closer to the filament and wall than their less massive and/or star-forming counterparts. Mass segregation persists among the star-forming population alone. The red fraction of galaxies increases when closing in on nodes, and on filaments regardless of the distance to nodes. Similarly, the star-forming population reddens (or lowers its sSFR) at fixed mass when closing in on filament, implying that some quenching takes place. These trends are also found in the state-of-the-art hydrodynamical simulation HORIZON-AGN. These results suggest that on top of stellar mass and large-scale density, the traceless component of the tides from the anisotropic large-scale environment also shapes galactic properties. An extension of excursion theory accounting for filamentary tides provides a qualitative explanation in terms of anisotropic assembly bias: at a given mass, the accretion rate varies with the orientation and distance to filaments. It also explains the absence of type/colour gradients in the data on smaller, non-linear scales.

REE compositions in fossil vertebrate dental tissues indicate biomineral preservation

NASA Astrophysics Data System (ADS)

Žigaite, Ž.; Kear, B.; Pérez-Huerta, A.; Jeffries, T.; Blom, H.

2012-04-01

Rare earth element (REE) abundances have been measured in a number of Palaeozoic and Mesozoic dental tissues using Laser Ablation Inductively Coupled Plasma Mass-spectrometry (LA-ICP-MS). Fossil vertebrates analysed comprise scales and tesserae of Silurian and Devonian acanthodians, chondrichthyans, galeaspids, mongolepids, thelodonts, as well as teeth of Cretaceous lungfish and marine reptiles. The evaluation of fossil preservation level has been made by semi-quantitative spot geochemistry analyses on fine polished teeth and scale thin sections, using Energy Dispersive X-ray Spectroscopy (EDS). Fossil teeth and scales with significant structure and colour alteration have shown elevated heavy element concentrations, and the silicification of bioapatite has been common in their tissues. Stable oxygen isotope measurements (δ18O) of bulk biomineral have been conducted in parallel, and showed comparatively lower heavy oxygen values in the same fossil tissues with stronger visible alteration. Significant difference in REE concentrations has been observed between the dentine and enamel of Cretaceous plesiosaurs, suggesting the enamel to be more geochemically resistant to diagenetic overprint.

FC colour images of dwarf planet Ceres reveal a complicated geological history

NASA Astrophysics Data System (ADS)

Nathues, A.; Hoffmann, M.; Platz, T.; Thangjam, G. S.; Cloutis, E. A.; Reddy, V.; Le Corre, L.; Li, J.-Y.; Mengel, K.; Rivkin, A.; Applin, D. M.; Schaefer, M.; Christensen, U.; Sierks, H.; Ripken, J.; Schmidt, B. E.; Hiesinger, H.; Sykes, M. V.; Sizemore, H. G.; Preusker, F.; Russell, C. T.

2016-12-01

The dwarf planet Ceres (equatorial diameter 963km) is the largest object that has remained in the main asteroid belt (Russell and Raymond, 2012), while most large bodies have been destroyed or removed by dynamical processes (Petit et al. 2001; Minton and Malhotra, 2009). Pre-Dawn investigations (McCord and Sotin, 2005; Castillo-Rogez and McCord, 2010; Castillo-Rogez et al., 2011) suggest that Ceres is a thermally evolved, but still volatile-rich body with potential geological activity, that was never completely molten, but possibly differentiated into a rocky core, an ice-rich mantle, and may contain remnant internal liquid water. Thermal alteration should contribute to producing a (dark) carbonaceous chondritic-like surface (McCord and Sotin, 2005; Castillo-Rogez and McCord, 2010; Castillo-Rogez et al., 2011; Nathues et al., 2015) containing ammoniated phyllosilicates (King et al., 1992; De Sanctis et al., 2015 and 2016). Here we show and analyse global contrast-rich colour mosaics, derived from a camera on-board Dawn at Ceres (Russell et al., 2016). Colours are unexpectedly more diverse on global scale than anticipated by Hubble Space Telescope (Li et al., 2006) and ground-based observations (Reddy et al. 2015). Dawn data led to the identification of five major colour units. The youngest units identified by crater counting, termed bright and bluish units, are exclusively found at equatorial and intermediate latitudes. We identified correlations between the distribution of the colour units, crater size, and formation age, inferring a crustal stratigraphy. Surface brightness and spectral properties are not correlated. The youngest surface features are the bright spots at crater Occator ( Ø 92km). Their colour spectra are highly consistent with the presence of carbonates while most of the remaining surface resembles modifications of various types of ordinary carbonaceous chondrites.

Halo models of HI selected galaxies

NASA Astrophysics Data System (ADS)

Paul, Niladri; Choudhury, Tirthankar Roy; Paranjape, Aseem

2018-06-01

Modelling the distribution of neutral hydrogen (HI) in dark matter halos is important for studying galaxy evolution in the cosmological context. We use a novel approach to infer the HI-dark matter connection at the massive end (m_H{I} > 10^{9.8} M_{⊙}) from radio HI emission surveys, using optical properties of low-redshift galaxies as an intermediary. In particular, we use a previously calibrated optical HOD describing the luminosity- and colour-dependent clustering of SDSS galaxies and describe the HI content using a statistical scaling relation between the optical properties and HI mass. This allows us to compute the abundance and clustering properties of HI-selected galaxies and compare with data from the ALFALFA survey. We apply an MCMC-based statistical analysis to constrain the free parameters related to the scaling relation. The resulting best-fit scaling relation identifies massive HI galaxies primarily with optically faint blue centrals, consistent with expectations from galaxy formation models. We compare the Hi-stellar mass relation predicted by our model with independent observations from matched Hi-optical galaxy samples, finding reasonable agreement. As a further application, we make some preliminary forecasts for future observations of HI and optical galaxies in the expected overlap volume of SKA and Euclid/LSST.

Validating Alternative Modes of Scoring for Coloured Progressive Matrices.

ERIC Educational Resources Information Center

Razel, Micha; Eylon, Bat-Sheva

Conventional scoring of the Coloured Progressive Matrices (CPM) was compared with three methods of multiple weight scoring. The methods include: (1) theoretical weighting in which the weights were based on a theory of cognitive processing; (2) judged weighting in which the weights were given by a group of nine adult expert judges; and (3)…

Colour Cues That Are Not Directly Attached to the Body of Males Do Not Influence the Mate Choice of Zebra Finches.

PubMed

Krause, E Tobias

2016-01-01

Mate choice decisions of female zebra finches are generally thought to rely on the assessment of male quality, which includes the specific ornamentation of males. A commonly used paradigm to experimentally manipulate a male's attractiveness is to add a coloured leg ring to the bird. Some studies have shown that female zebra finches prefer or alter their investment in males that have an additional red leg ring compared with males with green leg rings. Whether the coloured artificial ornaments need to be attached to the male's body or whether environmental colouration could have a similar effect on male attractiveness remains unclear. Here, I investigated this novel context to determine whether female choice between males is affected by environmental colour cues that are not directly attached to the male's body in four experiments involving 220 zebra finches (Taeniopygia guttata). A first experiment revealed that females chose males with red colour cues in the environmental background over males with green cues in the background. Based on this finding, I conducted follow-up experiments to obtain a deeper understanding of how environmental colour cues affect mate choice. Therefore, I examined whether female choice behaviour or male behaviour was altered in two additional experiments. Both experiments failed to show any effects of environmental colour cues on female choice or on male behaviour. Therefore, I replicated the initial experiment in a fourth experiment. Again replication failed; thus, the initial results indicating that environmental colouration affects mate choice behaviour of female zebra finches were not supported by the three subsequent experiments; thus, the outcome of the first experiment seems to be a false positive. Taking my results together, I found no robust support for the idea that environmental colour cues that are not directly attached to the body of male zebra finches affect female mate choice decisions.

Empirical photometric calibration of the Gaia red clump: Colours, effective temperature, and absolute magnitude

NASA Astrophysics Data System (ADS)

Ruiz-Dern, L.; Babusiaux, C.; Arenou, F.; Turon, C.; Lallement, R.

2018-01-01

Context. Gaia Data Release 1 allows the recalibration of standard candles such as the red clump stars. To use those stars, they first need to be accurately characterised. In particular, colours are needed to derive interstellar extinction. As no filter is available for the first Gaia data release and to avoid the atmosphere model mismatch, an empirical calibration is unavoidable. Aims: The purpose of this work is to provide the first complete and robust photometric empirical calibration of the Gaia red clump stars of the solar neighbourhood through colour-colour, effective temperature-colour, and absolute magnitude-colour relations from the Gaia, Johnson, 2MASS, HIPPARCOS, Tycho-2, APASS-SLOAN, and WISE photometric systems, and the APOGEE DR13 spectroscopic temperatures. Methods: We used a 3D extinction map to select low reddening red giants. To calibrate the colour-colour and the effective temperature-colour relations, we developed a MCMC method that accounts for all variable uncertainties and selects the best model for each photometric relation. We estimated the red clump absolute magnitude through the mode of a kernel-based distribution function. Results: We provide 20 colour versus G-Ks relations and the first Teff versus G-Ks calibration. We obtained the red clump absolute magnitudes for 15 photometric bands with, in particular, MKs = (-1.606 ± 0.009) and MG = (0.495 ± 0.009) + (1.121 ± 0.128)(G-Ks-2.1). We present a dereddened Gaia-TGAS HR diagram and use the calibrations to compare its red clump and its red giant branch bump with Padova isochrones. Full Table A.1 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/609/A116

A novel visualisation tool for climate services: a case study of temperature extremes and human mortality in Europe

NASA Astrophysics Data System (ADS)

Lowe, R.; Ballester, J.; Robine, J.; Herrmann, F. R.; Jupp, T. E.; Stephenson, D.; Rodó, X.

2013-12-01

Users of climate information often require probabilistic information on which to base their decisions. However, communicating information contained within a probabilistic forecast presents a challenge. In this paper we demonstrate a novel visualisation technique to display ternary probabilistic forecasts on a map in order to inform decision making. In this method, ternary probabilistic forecasts, which assign probabilities to a set of three outcomes (e.g. low, medium, and high risk), are considered as a point in a triangle of barycentric coordinates. This allows a unique colour to be assigned to each forecast from a continuum of colours defined on the triangle. Colour saturation increases with information gain relative to the reference forecast (i.e. the long term average). This provides additional information to decision makers compared with conventional methods used in seasonal climate forecasting, where one colour is used to represent one forecast category on a forecast map (e.g. red = ';dry'). We use the tool to present climate-related mortality projections across Europe. Temperature and humidity are related to human mortality via location-specific transfer functions, calculated using historical data. Daily mortality data at the NUTS2 level for 16 countries in Europe were obtain from 1998-2005. Transfer functions were calculated for 54 aggregations in Europe, defined using criteria related to population and climatological similarities. Aggregations are restricted to fall within political boundaries to avoid problems related to varying adaptation policies between countries. A statistical model is fit to cold and warm tails to estimate future mortality using forecast temperatures, in a Bayesian probabilistic framework. Using predefined categories of temperature-related mortality risk, we present maps of probabilistic projections for human mortality at seasonal to decadal time scales. We demonstrate the information gained from using this technique compared to more traditional methods to display ternary probabilistic forecasts. This technique allows decision makers to identify areas where the model predicts with certainty area-specific heat waves or cold snaps, in order to effectively target resources to those areas most at risk, for a given season or year. It is hoped that this visualisation tool will facilitate the interpretation of the probabilistic forecasts not only for public health decision makers but also within a multi-sectoral climate service framework.

Identification of areas of recharge and discharge using Landsat-TM satellite imagery and aerial photography mapping techniques

NASA Astrophysics Data System (ADS)

Salama, R. B.; Tapley, I.; Ishii, T.; Hawkes, G.

1994-10-01

Aerial photographs (AP) and Landsat (TM) colour composites were used to map the geomorphology, geology and structures of the Salt River System of Western Australia. Geomorphic features identified are sand plains, dissected etchplain, colluvium, lateritic duricrust and rock outcrops. The hydrogeomorphic units include streams, lakes and playas, palaeochannels and palaeodeltas. The structural features are linear and curvilinear lineaments, ring structures and dolerite dykes. Suture lines control the course of the main river channel. Permeable areas around the circular granitic plutons were found to be the main areas of recharge in the uplands. Recharge was also found to occur in the highly permeable areas of the sandplains. Discharge was shown to be primarily along the main drainage lines, on the edge of the circular sandplains, in depressions and in lakes. The groundwater occurrence and hydrogeological classification of the recharge potential of the different units were used to classify the mapped areas into recharge and discharge zones. The results also show that TM colour composites provide a viable source of data comparable with AP for mapping and delineating areas of recharge and discharge on a regional scale.

Properties of Am, Delta Del and Delta SCT stars in the VBLUW system

NASA Astrophysics Data System (ADS)

Wiertz, M. J. J.; van Genderen, A. M.

1983-05-01

VBLUW photometric observations of 115 Am, δ Del, and δ Sct stars are presented and discussed. The spread with respect to the main sequence in the two-colour diagrams is mainly attributed to gravity effects. Temperatures and gravities compare reasonably well with those of Davis Philip et al. (1976) based on uvbyß photometry. However, the temperatures derived by Babu and Shylaja (1981, 1982) and based on spectral energy distribution, reveal that the photometric temperatures (and thus also gravities) are underestimated. The relation between the temperature sensitive colour indices V-B (of the VBLUW system), b-y (ubvyß system) and B2-V1 (Geneva system) for A/F type stars is investigated. A PLC relation for the colour V-B is derived using Breger's (1979) relation for the colour b-y.

Differentiating Biological Colours with Few and Many Sensors: Spectral Reconstruction with RGB and Hyperspectral Cameras

PubMed Central

Garcia, Jair E.; Girard, Madeline B.; Kasumovic, Michael; Petersen, Phred; Wilksch, Philip A.; Dyer, Adrian G.

2015-01-01

Background The ability to discriminate between two similar or progressively dissimilar colours is important for many animals as it allows for accurately interpreting visual signals produced by key target stimuli or distractor information. Spectrophotometry objectively measures the spectral characteristics of these signals, but is often limited to point samples that could underestimate spectral variability within a single sample. Algorithms for RGB images and digital imaging devices with many more than three channels, hyperspectral cameras, have been recently developed to produce image spectrophotometers to recover reflectance spectra at individual pixel locations. We compare a linearised RGB and a hyperspectral camera in terms of their individual capacities to discriminate between colour targets of varying perceptual similarity for a human observer. Main Findings (1) The colour discrimination power of the RGB device is dependent on colour similarity between the samples whilst the hyperspectral device enables the reconstruction of a unique spectrum for each sampled pixel location independently from their chromatic appearance. (2) Uncertainty associated with spectral reconstruction from RGB responses results from the joint effect of metamerism and spectral variability within a single sample. Conclusion (1) RGB devices give a valuable insight into the limitations of colour discrimination with a low number of photoreceptors, as the principles involved in the interpretation of photoreceptor signals in trichromatic animals also apply to RGB camera responses. (2) The hyperspectral camera architecture provides means to explore other important aspects of colour vision like the perception of certain types of camouflage and colour constancy where multiple, narrow-band sensors increase resolution. PMID:25965264

Colour, phenolic content and antioxidant capacity of some fruits dehydrated by a combination of different methods.

PubMed

Chong, Chien Hwa; Law, Chung Lim; Figiel, Adam; Wojdyło, Aneta; Oziembłowski, Maciej

2013-12-15

The objective of this study was to improve product quality of dehydrated fruits (apple, pear, papaya, mango) using combined drying techniques. This involved investigation of bioactivity, colour, and sensory assessment on colour of the dried products as well as the retention of the bio-active ingredients. The attributes of quality were compared in regard to the quality of dehydrated samples obtained from continuous heat pump (HP) drying technique. It was found that for apple, pear and mango the total colour change (ΔE) of samples dried using continuous heat pump (HP) or heat pump vacuum-microwave (HP/VM) methods was lower than of samples dried by other combined methods. However, for papaya, the lowest colour change exhibited by samples dried using hot air-cold air (HHC) method and the highest colour change was found for heat pump (HP) dehydrated samples. Sensory evaluation revealed that dehydrated pear with higher total colour change (ΔE) is more desirable because of its golden yellow appearance. In most cases the highest phenol content was found from fruits dried by HP/VM method. Judging from the quality findings on two important areas namely colour and bioactivity, it was found that combined drying method consisted of HP pre-drying followed by VM finish drying gave the best results for most dehydrated fruits studied in this work as the fruits contain first group of polyphenol compounds, which preferably requires low temperature followed by rapid drying strategy. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

The colour of a football outfit affects visibility and team success.

PubMed

Olde Rikkert, Joris; Haes, Vincent De; Barsingerhorn, Annemiek D; Theelen, Thomas; Olde Rikkert, Marcel G M

2015-01-01

We investigated the impact of the colour of football outfits on localising football players and on the results of football matches. Two studies were conducted: an experimental study examining the effects of outfit colour on the assessment of the positions of computer-animated football players in a video set-up (study 1) and a retrospective study on professional football clubs' performances dependent on their outfit colours (study 2). The studies were conducted with 18 human volunteers aged 15-18 years (study 1) and league results from 10 professional European football teams over 17 years (1995-2013) (study 2). We analysed the number of correct assessments of the positions of virtual football players with different outfit colours (study 1) and analysed the relationship between match results and outfits' colours (study 2). Study 1 showed that the position of players wearing white outfits was better assessed in 5.2% of the trials compared to players wearing green outfits (P = 0.007). Study 2 showed that Manchester City conceded less goals against in away games in highly visible kits (r = 0.62; P = 0.024), while Newcastle United conceded less goals and won more points while playing in kits associated with low visibility (r = 0.63; P = 0.007; r = 0.50; P = 0.040, respectively). We conclude that the colour of football outfits affects evaluations of football players' positions on the field, with white tricots resulting in the best location assessment. The outfit colour may indirectly influence football match results, warranting more attention to the home and away shirts by team managers and football scientists.

A learning approach to the bandwidth multicolouring problem

NASA Astrophysics Data System (ADS)

Akbari Torkestani, Javad

2016-05-01

In this article, a generalisation of the vertex colouring problem known as bandwidth multicolouring problem (BMCP), in which a set of colours is assigned to each vertex such that the difference between the colours, assigned to each vertex and its neighbours, is by no means less than a predefined threshold, is considered. It is shown that the proposed method can be applied to solve the bandwidth colouring problem (BCP) as well. BMCP is known to be NP-hard in graph theory, and so a large number of approximation solutions, as well as exact algorithms, have been proposed to solve it. In this article, two learning automata-based approximation algorithms are proposed for estimating a near-optimal solution to the BMCP. We show, for the first proposed algorithm, that by choosing a proper learning rate, the algorithm finds the optimal solution with a probability close enough to unity. Moreover, we compute the worst-case time complexity of the first algorithm for finding a 1/(1-ɛ) optimal solution to the given problem. The main advantage of this method is that a trade-off between the running time of algorithm and the colour set size (colouring optimality) can be made, by a proper choice of the learning rate also. Finally, it is shown that the running time of the proposed algorithm is independent of the graph size, and so it is a scalable algorithm for large graphs. The second proposed algorithm is compared with some well-known colouring algorithms and the results show the efficiency of the proposed algorithm in terms of the colour set size and running time of algorithm.

Qualitative identification of permitted and non-permitted colour additives in food products.

PubMed

Harp, Bhakti Petigara; Miranda-Bermudez, Enio; Baron, Carolina I; Richard, Gerald I

2012-01-01

Colour additives are dyes, pigments or other substances that can impart colour when added or applied to food, drugs, cosmetics, medical devices, or the human body. The substances must be pre-approved by the US Food and Drug Administration (USFDA) and listed in Title 21 of the US Code of Federal Regulations before they may be used in products marketed in the United States. Some also are required to be batch certified by the USFDA prior to their use. Both domestic and imported products sold in interstate commerce fall under USFDA jurisdiction, and the USFDA's district laboratories use a combination of analytical methods for identifying or confirming the presence of potentially violative colour additives. We have developed a qualitative method for identifying 17 certifiable, certification exempt, and non-permitted colour additives in various food products. The method involves extracting the colour additives from a product and isolating them from non-coloured components with a C(18) Sep-Pak cartridge. The colour additives are then separated and identified by liquid chromatography (LC) with photodiode array detection, using an Xterra RP18 column and gradient elution with aqueous ammonium acetate and methanol. Limits of detection (LODs) ranged from 0.02 to 1.49 mg/l. This qualititative LC method supplements the visible spectrophotometric and thin-layer chromatography methods currently used by the USFDA's district laboratories and is less time-consuming and requires less solvent compared to the other methods. The extraction step in the new LC method is a simple and an efficient process that can be used for most food types.

Colour-induced relationship between affect and reaching kinematics during a goal-directed aiming task.

PubMed

Williams, Camille K; Grierson, Lawrence E M; Carnahan, Heather

2011-08-01

A link between affect and action has been supported by the discovery that threat information is prioritized through an action-centred pathway--the dorsal visual stream. Magnocellular afferents, which originate from the retina and project to dorsal stream structures, are suppressed by exposure to diffuse red light, which diminishes humans' perception of threat-based images. In order to explore the role of colour in the relationship between affect and action, participants donned different pairs of coloured glasses (red, yellow, green, blue and clear) and completed Positive and Negative Affect Scale questionnaires as well as a series of target-directed aiming movements. Analyses of affect scores revealed a significant main effect for affect valence and a significant interaction between colour and valence: perceived positive affect was significantly smaller for the red condition. Kinematic analyses of variable error in the primary movement direction and Pearson correlation analyses between the displacements travelled prior to and following peak velocity indicated reduced accuracy and application of online control processes while wearing red glasses. Variable error of aiming was also positively and significantly correlated with negative affect scores under the red condition. These results suggest that only red light modulates the affect-action link by suppressing magnocellular activity, which disrupts visual processing for movement control. Furthermore, previous research examining the effect of the colour red on psychomotor tasks and perceptual acceleration of threat-based imagery suggest that stimulus-driven motor performance tasks requiring online control may be particularly susceptible to this effect.

Description and spatial inference of soil drainage using matrix soil colours in the Lower Hunter Valley, New South Wales, Australia

PubMed Central

McBratney, Alex B.; Minasny, Budiman

2018-01-01

Soil colour is often used as a general purpose indicator of internal soil drainage. In this study we developed a necessarily simple model of soil drainage which combines the tacit knowledge of the soil surveyor with observed matrix soil colour descriptions. From built up knowledge of the soils in our Lower Hunter Valley, New South Wales study area, the sequence of well-draining → imperfectly draining → poorly draining soils generally follows the colour sequence of red → brown → yellow → grey → black soil matrix colours. For each soil profile, soil drainage is estimated somewhere on a continuous index of between 5 (very well drained) and 1 (very poorly drained) based on the proximity or similarity to reference soil colours of the soil drainage colour sequence. The estimation of drainage index at each profile incorporates the whole-profile descriptions of soil colour where necessary, and is weighted such that observation of soil colour at depth and/or dominantly observed horizons are given more preference than observations near the soil surface. The soil drainage index, by definition disregards surficial soil horizons and consolidated and semi-consolidated parent materials. With the view to understanding the spatial distribution of soil drainage we digitally mapped the index across our study area. Spatial inference of the drainage index was made using Cubist regression tree model combined with residual kriging. Environmental covariates for deterministic inference were principally terrain variables derived from a digital elevation model. Pearson’s correlation coefficients indicated the variables most strongly correlated with soil drainage were topographic wetness index (−0.34), mid-slope position (−0.29), multi-resolution valley bottom flatness index (−0.29) and vertical distance to channel network (VDCN) (0.26). From the regression tree modelling, two linear models of soil drainage were derived. The partitioning of models was based upon threshold criteria of VDCN. Validation of the regression kriging model using a withheld dataset resulted in a root mean square error of 0.90 soil drainage index units. Concordance between observations and predictions was 0.49. Given the scale of mapping, and inherent subjectivity of soil colour description, these results are acceptable. Furthermore, the spatial distribution of soil drainage predicted in our study area is attuned with our mental model developed over successive field surveys. Our approach, while exclusively calibrated for the conditions observed in our study area, can be generalised once the unique soil colour and soil drainage relationship is expertly defined for an area or region in question. With such rules established, the quantitative components of the method would remain unchanged. PMID:29682425

Description and spatial inference of soil drainage using matrix soil colours in the Lower Hunter Valley, New South Wales, Australia.

PubMed

Malone, Brendan P; McBratney, Alex B; Minasny, Budiman

2018-01-01

Soil colour is often used as a general purpose indicator of internal soil drainage. In this study we developed a necessarily simple model of soil drainage which combines the tacit knowledge of the soil surveyor with observed matrix soil colour descriptions. From built up knowledge of the soils in our Lower Hunter Valley, New South Wales study area, the sequence of well-draining → imperfectly draining → poorly draining soils generally follows the colour sequence of red → brown → yellow → grey → black soil matrix colours. For each soil profile, soil drainage is estimated somewhere on a continuous index of between 5 (very well drained) and 1 (very poorly drained) based on the proximity or similarity to reference soil colours of the soil drainage colour sequence. The estimation of drainage index at each profile incorporates the whole-profile descriptions of soil colour where necessary, and is weighted such that observation of soil colour at depth and/or dominantly observed horizons are given more preference than observations near the soil surface. The soil drainage index, by definition disregards surficial soil horizons and consolidated and semi-consolidated parent materials. With the view to understanding the spatial distribution of soil drainage we digitally mapped the index across our study area. Spatial inference of the drainage index was made using Cubist regression tree model combined with residual kriging. Environmental covariates for deterministic inference were principally terrain variables derived from a digital elevation model. Pearson's correlation coefficients indicated the variables most strongly correlated with soil drainage were topographic wetness index (-0.34), mid-slope position (-0.29), multi-resolution valley bottom flatness index (-0.29) and vertical distance to channel network (VDCN) (0.26). From the regression tree modelling, two linear models of soil drainage were derived. The partitioning of models was based upon threshold criteria of VDCN. Validation of the regression kriging model using a withheld dataset resulted in a root mean square error of 0.90 soil drainage index units. Concordance between observations and predictions was 0.49. Given the scale of mapping, and inherent subjectivity of soil colour description, these results are acceptable. Furthermore, the spatial distribution of soil drainage predicted in our study area is attuned with our mental model developed over successive field surveys. Our approach, while exclusively calibrated for the conditions observed in our study area, can be generalised once the unique soil colour and soil drainage relationship is expertly defined for an area or region in question. With such rules established, the quantitative components of the method would remain unchanged.

A Comparative Study on Diagnostic Accuracy of Colour Coded Digital Images, Direct Digital Images and Conventional Radiographs for Periapical Lesions – An In Vitro Study

PubMed Central

Mubeen; K.R., Vijayalakshmi; Bhuyan, Sanat Kumar; Panigrahi, Rajat G; Priyadarshini, Smita R; Misra, Satyaranjan; Singh, Chandravir

2014-01-01

Objectives: The identification and radiographic interpretation of periapical bone lesions is important for accurate diagnosis and treatment. The present study was undertaken to study the feasibility and diagnostic accuracy of colour coded digital radiographs in terms of presence and size of lesion and to compare the diagnostic accuracy of colour coded digital images with direct digital images and conventional radiographs for assessing periapical lesions. Materials and Methods: Sixty human dry cadaver hemimandibles were obtained and periapical lesions were created in first and second premolar teeth at the junction of cancellous and cortical bone using a micromotor handpiece and carbide burs of sizes 2, 4 and 6. After each successive use of round burs, a conventional, RVG and colour coded image was taken for each specimen. All the images were evaluated by three observers. The diagnostic accuracy for each bur and image mode was calculated statistically. Results: Our results showed good interobserver (kappa > 0.61) agreement for the different radiographic techniques and for the different bur sizes. Conventional Radiography outperformed Digital Radiography in diagnosing periapical lesions made with Size two bur. Both were equally diagnostic for lesions made with larger bur sizes. Colour coding method was least accurate among all the techniques. Conclusion: Conventional radiography traditionally forms the backbone in the diagnosis, treatment planning and follow-up of periapical lesions. Direct digital imaging is an efficient technique, in diagnostic sense. Colour coding of digital radiography was feasible but less accurate however, this imaging technique, like any other, needs to be studied continuously with the emphasis on safety of patients and diagnostic quality of images. PMID:25584318

A pilot study to assess if urine specific gravity and urine colour charts are useful indicators of dehydration in acute stroke patients.

PubMed

Rowat, Anne; Smith, Laura; Graham, Cat; Lyle, Dawn; Horsburgh, Dorothy; Dennis, Martin

2011-09-01

The purpose of this pilot study was to examine whether urine specific gravity and urine colour could provide an early warning of dehydration in stroke patients compared with standard blood indicators of hydration status. Dehydration after stroke has been associated with increased blood viscosity, venous thrombo-embolism and stroke mortality at 3-months. Earlier identification of dehydration might allow us to intervene to prevent significant dehydration developing or reduce its duration to improve patient outcomes. We recruited 20 stroke patients in 2007 and measured their urine specific gravity with urine test strips, a refractometer, and urine colour of specimens taken daily on 10 consecutive days and compared with the routine blood urea:creatinine ratios over the same period to look for trends and relationships over time. The agreement between the refractometer, test strips and urine colour were expressed as a percentage with 95% confidence intervals. Nine (45%) of the 20 stroke patients had clinical signs of dehydration and had a significantly higher admission median urea:creatinine ratio (P = 0·02, Mann-Whitney U-test). There were no obvious relationships between urine specific gravity and urine colour with the urea:creatinine ratio. Of the 174 urine samples collected, the refractometer agreed with 70/174 (40%) urine test strip urine specific gravity and 117/174 (67%) urine colour measurements. Our results do not support the use of the urine test strip urine specific gravity as an early indicator of dehydration. Further research is required to develop a practical tool for the early detection of dehydration in stroke patients. © 2011 Blackwell Publishing Ltd.

Simultaneous colour visualizations of multiple ALS point cloud attributes for land cover and vegetation analysis

NASA Astrophysics Data System (ADS)

Zlinszky, András; Schroiff, Anke; Otepka, Johannes; Mandlburger, Gottfried; Pfeifer, Norbert

2014-05-01

LIDAR point clouds hold valuable information for land cover and vegetation analysis, not only in the spatial distribution of the points but also in their various attributes. However, LIDAR point clouds are rarely used for visual interpretation, since for most users, the point cloud is difficult to interpret compared to passive optical imagery. Meanwhile, point cloud viewing software is available allowing interactive 3D interpretation, but typically only one attribute at a time. This results in a large number of points with the same colour, crowding the scene and often obscuring detail. We developed a scheme for mapping information from multiple LIDAR point attributes to the Red, Green, and Blue channels of a widely used LIDAR data format, which are otherwise mostly used to add information from imagery to create "photorealistic" point clouds. The possible combinations of parameters are therefore represented in a wide range of colours, but relative differences in individual parameter values of points can be well understood. The visualization was implemented in OPALS software, using a simple and robust batch script, and is viewer independent since the information is stored in the point cloud data file itself. In our case, the following colour channel assignment delivered best results: Echo amplitude in the Red, echo width in the Green and normalized height above a Digital Terrain Model in the Blue channel. With correct parameter scaling (but completely without point classification), points belonging to asphalt and bare soil are dark red, low grassland and crop vegetation are bright red to yellow, shrubs and low trees are green and high trees are blue. Depending on roof material and DTM quality, buildings are shown from red through purple to dark blue. Erroneously high or low points, or points with incorrect amplitude or echo width usually have colours contrasting from terrain or vegetation. This allows efficient visual interpretation of the point cloud in planar, profile and 3D views since it reduces crowding of the scene and delivers intuitive contextual information. The resulting visualization has proved useful for vegetation analysis for habitat mapping, and can also be applied as a first step for point cloud level classification. An interactive demonstration of the visualization script is shown during poster attendance, including the opportunity to view your own point cloud sample files.

HRSCview: a web-based data exploration system for the Mars Express HRSC instrument

NASA Astrophysics Data System (ADS)

Michael, G.; Walter, S.; Neukum, G.

2007-08-01

The High Resolution Stereo Camera (HRSC) on the ESA Mars Express spacecraft has been orbiting Mars since January 2004. By spring 2007 it had returned around 2 terabytes of image data, covering around 35% of the Martian surface in stereo and colour at a resolu-tion of 10-20 m/pixel. HRSCview provides a rapid means to explore these images up to their full resolu-tion with the data-subsetting, sub-sampling, stretching and compositing being carried out on-the-fly by the image server. It is a joint website of the Free University of Berlin and the German Aerospace Center (DLR). The system operates by on-the-fly processing of the six HRSC level-4 image products: the map-projected ortho-rectified nadir pan-chromatic and four colour channels, and the stereo-derived DTM (digital terrain model). The user generates a request via the web-page for an image with several parameters: the centre of the view in surface coordinates, the image resolution in metres/pixel, the image dimensions, and one of several colour modes. If there is HRSC coverage at the given location, the necessary segments are extracted from the full orbit images, resampled to the required resolution, and composited according to the user's choice. In all modes the nadir channel, which has the highest resolu-tion, is included in the composite so that the maximum detail is always retained. The images are stretched ac-cording to the current view: this applies to the eleva-tion colour scale, as well as the nadir brightness and the colour channels. There are modes for raw colour, stretched colour, enhanced colour (exaggerated colour differences), and a synthetic 'Mars-like' colour stretch. A colour ratio mode is given as an alternative way to examine colour differences (R=IR/R, G=R/G and B=G/B). The final image is packaged as a JPEG file and returned to the user over the web. Each request requires approximately 1 second to process. A link is provided from each view to a data product page, where header items describing the full map-projected science data product are displayed, and a direct link to the archived data products on the ESA Planetary Science Archive (PSA) is provided. At pre-sent the majority of the elevation composites are de-rived from the HRSC Preliminary 200m DTMs gener-ated at the German Aerospace Center (DLR), which will not be available as separately downloadable data products. These DTMs are being progressively super-seded by systematically generated higher resolution archival DTMs, also from DLR, which will become available for download through the PSA, and be simi-larly accessible via HRSCview. At the time of writing this abstract (May 2007), four such high resolution DTMs are available for download via the HRSCview data product pages (for images from orbits 0572, 0905, 1004, and 2039).

In vivo evaluation of some biophysical parameters of the facial skin of Indian subjects living in Mumbai. Part II: Variability with age and gender.

PubMed

Colomb, L; Flament, F; Wagle, A; Idelcaid, Y; Agrawal, D

2018-04-01

A previously published work explored the diversity of some biophysical parameters (colour, elasticity, sebum production, skin microrelief, etc.) of the skin of 1204 Indian women, differently aged, living in four Indian cities (Chennai, Delhi, Kolkata and Mumbai). The present work aimed at completing such research by focusing on possible gender-related differences in the same skin parameters, between Indian men and women living in the same Indian city (Mumbai). A total of 297 Indian men, differently aged (18-70y), were recruited in Mumbai, completing the panel of 303 women who were previously recruited in this same city. The same instrumental measurements of facial skin colour and its homogeneity, its mechanical properties, the sebum production, skin pores size, skin relief, etc. as in the previous work, were conducted. Overall, the facial skin colour shows a darker complexion in men as compared to women, on forehead, ocular region, lips, chin and cheek. The skin colour unevenness, which increases with age, was found higher in men, as compared to women. At comparable age, women and men present a same density of skin pores, whereas those of men appear larger, up to 55y. The deepness of Crow's feet wrinkles does not significantly differ between genders. A lesser extensibility was found on the cheeks of men. In men, the sebum production was found significantly higher than that of women at ages above 40y. This work indicates some commonly shared age-related skin features between women and men from Mumbai, despite slight different characteristics such as skin pigmentation, forehead/cheek colour contrast, mechanical properties and sebum production. © 2018 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Synthetic Stellar Photometry - II. Testing the bolometric flux scale and tables of bolometric corrections for the Hipparcos/Tycho, Pan-STARRS1, SkyMapper, and JWST systems

NASA Astrophysics Data System (ADS)

Casagrande, L.; VandenBerg, Don A.

2018-04-01

We use MARCS model atmosphere fluxes to compute synthetic colours, bolometric corrections and reddening coefficients for the Hipparcos/Tycho, Pan-STARRS1, SkyMapper, and JWST systems. Tables and interpolation subroutines are provided to transform isochrones from the theoretical to various observational planes, to derive bolometric corrections, synthetic colours and colour-temperature relations at nearly any given point of the HR diagram for 2600 K ≤ Teff ≤ 8000 K, and different values of reddening in 85 photometric filters. We use absolute spectrophotometry from the CALSPEC library to show that bolometric fluxes can be recovered to ˜2 per cent from bolometric corrections in a single band, when input stellar parameters are well known for FG dwarfs at various metallicities. This sole source of uncertainty impacts interferometric Teff to ≃0.5 per cent (or 30 K at the solar temperature). Uncertainties are halved when combining bolometric corrections in more bands, and limited by the fundamental uncertainty of the current absolute flux scale at 1 per cent. Stars in the RAVE DR5 catalogue are used to validate the quality of our MARCS synthetic photometry in selected filters across the optical and infrared range. This investigation shows that extant MARCS synthetic fluxes are able to reproduce the main features observed in stellar populations across the Galactic disc.

Application of Sensor Fusion to Improve Uav Image Classification

NASA Astrophysics Data System (ADS)

Jabari, S.; Fathollahi, F.; Zhang, Y.

2017-08-01

Image classification is one of the most important tasks of remote sensing projects including the ones that are based on using UAV images. Improving the quality of UAV images directly affects the classification results and can save a huge amount of time and effort in this area. In this study, we show that sensor fusion can improve image quality which results in increasing the accuracy of image classification. Here, we tested two sensor fusion configurations by using a Panchromatic (Pan) camera along with either a colour camera or a four-band multi-spectral (MS) camera. We use the Pan camera to benefit from its higher sensitivity and the colour or MS camera to benefit from its spectral properties. The resulting images are then compared to the ones acquired by a high resolution single Bayer-pattern colour camera (here referred to as HRC). We assessed the quality of the output images by performing image classification tests. The outputs prove that the proposed sensor fusion configurations can achieve higher accuracies compared to the images of the single Bayer-pattern colour camera. Therefore, incorporating a Pan camera on-board in the UAV missions and performing image fusion can help achieving higher quality images and accordingly higher accuracy classification results.

Comparison of computer display monitors for computed radiography diagnostic application in a radiology PACS.

PubMed

Sim, L; Manthey, K; Esdaile, P; Benson, M

2004-09-01

A study to compare the performance of the following display monitors for application as PACS CR diagnostic workstations is described. 1. Diagnostic quality, 3 megapixel, 21 inch monochrome LCD monitors. 2. Commercial grade, 2 megapixel, 20 inch colour LCD monitors. Two sets of fifty radiological studies each were presented separately to five radiologists on two occasions, using different displays on each occasion. The two sets of radiological studies were CR of the chest, querying the presence of pneumothorax, and CR of the wrist, querying the presence of a scaphoid fracture. Receiver Operating Characteristic (ROC) curves were constructed for diagnostic performance for each presentation. Areas under the ROC curves (AUC) for diagnosis using different monitors were compared for each image set and the following results obtained: Set 1: Monochrome AUC = 0.873 +/- 0.026; Colour AUC = 0.831 +/- 0.032; Set 2: Monochrome AUC = 0.945 +/- 0.014; Colour AUC = 0.931 +/- 0.019; Differences in AUC were attributed to the different monitors. While not significant at a 95% confidence level, the results have supported a cautious approach to consideration of the use of commercial grade LCD colour monitors for diagnostic application.

A hydrophilic interaction liquid chromatography-mass spectrometry (HILIC-MS) based metabolomics study on colour stability of ovine meat.

PubMed

Subbaraj, Arvind K; Kim, Yuan H Brad; Fraser, Karl; Farouk, Mustafa M

2016-07-01

Meat colour is one of the cues available to the consumer to gauge overall meat quality and wholesomeness. Colour stability of meat is determined by several factors both inherent to the animal and post-slaughter conditions, including ageing, storage/packaging and display times. A hydrophilic interaction liquid chromatography-mass spectrometry (HILIC-MS) based metabolomics study was undertaken to identify and compare polar metabolites between ovine meat samples that were exposed to different durations of ageing, storage conditions, and display times. Primary metabolites comprising amino acids, sugars, nucleotides, nucleosides, organic acids and their breakdown products were mainly identified as discriminating factors. For the first time, boron complexes of sugar and malic acid were also tentatively identified. As expected, most compounds identified were related to myoglobin chemistry, and compounds with antioxidant properties were found in higher levels in colour stable samples. Supplementary studies identifying semi-polar, non-polar and volatile compounds will provide a holistic understanding of the chemical basis of colour stability in ovine meat. Copyright © 2016 Elsevier Ltd. All rights reserved.

Colour gamut mapping between small and large colour gamuts: Part I. gamut compression.

PubMed

Xu, Lihao; Zhao, Baiyue; Luo, M R

2018-04-30

This paper describes an investigation into the performance of different gamut compression algorithms (GCAs) in different uniform colour spaces (UCSs) between small and large colour gamuts. Gamut mapping is a key component in a colour management system and has drawn much attention in the last two decades. Two new GCAs, i.e. vividness-preserved (VP) and depth-preserved (DP), based on the concepts of 'vividness' and 'depth' are proposed and compared with the other commonly used GCAs with the exception of spatial GCAs since the goal of this study was to develop an algorithm that could be implemented in real time for mobile phone applications. In addition, UCSs including CIELAB, CAM02-UCS, and a newly developed UCS, J z a z b z , were tested to verify how they affect the performance of the GCAs. A psychophysical experiment was conducted and the results showed that one of the newly proposed GCAs, VP, gave the best performance among different GCAs and the J z a z b z is a promising UCS for gamut mapping.

Effects of radio frequency and high pressure steam sterilisation on the colour and flavour of prepared Nostoc sphaeroides.

PubMed

Xu, Jicheng; Zhang, Min; An, Yanjun; Roknul, Azam Sm; Adhikari, Benu

2018-03-01

Nostoc sphaeroides has been used as a highly effective herbal medicine and dietary supplement for thousands of years. The desired dark green colour of fresh N. sphaeroides is converted into an undesirable dark brown during conventional high pressure (HP) steam sterilisation. Radio frequency (RF) sterilisation technology was used in this study to determine its effectiveness in sterilising N. sphaeroides and to achieve better preservation of natural colour and desirable flavour. Sterilisation was carried out using a 6 kW, 27 MHz RF instrument for 10, 20 and 30 min. The degree of microbial kill and the effects of RF sterilisation on colour and flavour were determined and compared with those obtained from HP steam (121 °C, 30 min) sterilisation. The effects of RF sterilisation on colour and flavour (measured using electronic nose) parameters were significantly lower than that in HP steam sterilisation. The RF sterilisation carried out for 20 min achieved logarithmic reduction of bacterial population and met China's national standard while preserving the colour and flavour better. Results of the present study indicated that application of RF sterilisation would improve the quality of sterilised N. sphaeroides and broaden its application in the food and health food industries. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Floral colours in a world without birds and bees: the plants of Macquarie Island.

PubMed

Shrestha, M; Lunau, K; Dorin, A; Schulze, B; Bischoff, M; Burd, M; Dyer, A G

2016-09-01

We studied biotically pollinated angiosperms on Macquarie Island, a remote site in the Southern Ocean with a predominately or exclusively dipteran pollinator fauna, in an effort to understand how flower colour affects community assembly. We compared a distinctive group of cream-green Macquarie Island flowers to the flora of likely source pools of immigrants and to a continental flora from a high latitude in the northern hemisphere. We used both dipteran and hymenopteran colour models and phylogenetically informed analyses to explore the chromatic component of community assembly. The species with cream-green flowers are very restricted in colour space models of both fly vision and bee vision and represent a distinct group that plays a very minor role in other communities. It is unlikely that such a community could form through random immigration from continental source pools. Our findings suggest that fly pollination has imposed a strong ecological filter on Macquarie Island, favouring floral colours that are rare in continental floras. This is one of the strongest demonstrations that plant-pollinator interactions play an important role in plant community assembly. Future work exploring colour choices by dipteran flower visitors would be valuable. © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.

Controllable liquid colour-changing lenses with microfluidic channels for vision protection, camouflage and optical filtering based on soft lithography fabrication.

PubMed

Zhang, Min; Li, Songjing

2016-01-01

In this work, liquid colour-changing lenses for vision protection, camouflage and optical filtering are developed by circulating colour liquids through microfluidic channels on the lenses manually. Soft lithography technology is applied to fabricate the silicone liquid colour-changing layers with microfluidic channels on the lenses instead of mechanical machining. To increase the hardness and abrasion resistance of the silicone colour-changing layers on the lenses, proper fabrication parameters such as 6:1 (mass ration) mixing proportion and 100 °C curing temperature for 2 h are approved for better soft lithography process of the lenses. Meanwhile, a new surface treatment for the irreversible bonding of silicone colour-changing layer with optical resin (CR39) substrate lens by using 5 % (volume ratio) 3-Aminopropyltriethoxysilane solution is proposed. Vision protection, camouflage and optical filtering functions of the lenses are investigated with different designs of the channels and multi-layer structures. Each application can not only well achieve their functional demands, but also shows the advantages of functional flexibility, rapid prototyping and good controllability compared with traditional ways. Besides optometry, some other designs and applications of the lenses are proposed for potential utility in the future.

Contribution of sulfur-containing compounds to the colour-inhibiting effect and improved antioxidant activity of Maillard reaction products of soybean protein hydrolysates.

PubMed

Huang, Meigui; Liu, Ping; Song, Shiqing; Zhang, Xiaoming; Hayat, Khizar; Xia, Shuqin; Jia, Chengsheng; Gu, Fenglin

2011-03-15

Light-coloured and savoury-tasting flavour enhancers are attractive to both consumers and food producers. The aim of this study was to investigate the colour-inhibiting effect of L-cysteine and thiamine during the Maillard reaction of soybean peptide and D-xylose. The correlation between volatile compounds and antioxidant activity of the corresponding products was also studied. Colour formation was markedly suppressed by cysteine. Compared with peptide/xylose (PX), the taste profile of Maillard reaction products (MRPs) derived from peptide/xylose/cysteine (PXC) and peptide/xylose/cysteine/thiamine (PXCT) was stronger, including umami, mouthfulness, continuity, meaty and overall acceptance. PXC and PXCT also exihibited distinctly higher antioxidant activity. Principal component analysis was applied to investigate the correlation between antioxidant activity and volatile compounds. Of 88 volatile compounds identified, 55 were significantly correlated with antioxidant activity by two principal components (accounting for 85.05% of the total variance). Effective colour control of the Maillard reaction by L-cysteine may allow the production of healthier (higher antioxidant activity) and tastier foods to satisfy consumers' and food producers' demands. Light-coloured products might be used as functional flavour enhancers in various food systems. Copyright © 2010 Society of Chemical Industry.

3D digital image correlation using a single 3CCD colour camera and dichroic filter

NASA Astrophysics Data System (ADS)

Zhong, F. Q.; Shao, X. X.; Quan, C.

2018-04-01

In recent years, three-dimensional digital image correlation methods using a single colour camera have been reported. In this study, we propose a simplified system by employing a dichroic filter (DF) to replace the beam splitter and colour filters. The DF can be used to combine two views from different perspectives reflected by two planar mirrors and eliminate their interference. A 3CCD colour camera is then used to capture two different views simultaneously via its blue and red channels. Moreover, the measurement accuracy of the proposed method is higher since the effect of refraction is reduced. Experiments are carried out to verify the effectiveness of the proposed method. It is shown that the interference between the blue and red views is insignificant. In addition, the measurement accuracy of the proposed method is validated on the rigid body displacement. The experimental results demonstrate that the measurement accuracy of the proposed method is higher compared with the reported methods using a single colour camera. Finally, the proposed method is employed to measure the in- and out-of-plane displacements of a loaded plastic board. The re-projection errors of the proposed method are smaller than those of the reported methods using a single colour camera.

Visual awareness of objects and their colour.

PubMed

Pilling, Michael; Gellatly, Angus

2011-10-01

At any given moment, our awareness of what we 'see' before us seems to be rather limited. If, for instance, a display containing multiple objects is shown (red or green disks), when one object is suddenly covered at random, observers are often little better than chance in reporting about its colour (Wolfe, Reinecke, & Brawn, Visual Cognition, 14, 749-780, 2006). We tested whether, when object attributes (such as colour) are unknown, observers still retain any knowledge of the presence of that object at a display location. Experiments 1-3 involved a task requiring two-alternative (yes/no) responses about the presence or absence of a colour-defined object at a probed location. On this task, if participants knew about the presence of an object at a location, responses indicated that they also knew about its colour. A fourth experiment presented the same displays but required a three-alternative response. This task did result in a data pattern consistent with participants' knowing more about the locations of objects within a display than about their individual colours. However, this location advantage, while highly significant, was rather small in magnitude. Results are compared with those of Huang (Journal of Vision, 10(10, Art. 24), 1-17, 2010), who also reported an advantage for object locations, but under quite different task conditions.

Squids old and young: Scale-free design for a simple billboard

NASA Astrophysics Data System (ADS)

Packard, Andrew

2011-03-01

Squids employ a large range of brightness-contrast spatial frequencies in their camouflage and signalling displays. The 'billboard' of coloured elements ('spots'=chromatophore organs) in the skin is built autopoietically-probably by lateral inhibitory processes-and enlarges as much as 10,000-fold during development. The resulting two-dimensional array is a fractal-like colour/size hierarchy lying in several layers of a multilayered network. Dynamic control of the array by muscles and nerves produces patterns that recall 'half-tone' processing (cf. ink-jet printer). In the more sophisticated (loliginid) squids, patterns also combine 'continuous tones' (cf. dye-sublimation printer). Physiologists and engineers can exploit the natural colour-coding of the integument to understand nerve and muscle system dynamics, examined here at the level of the ensemble. Integrative functions of the whole (H) are analysed in terms of the power spectrum within and between ensembles and of spontaneous waves travelling through the billboard. Video material may be obtained from the author at the above address.

Colour flow and motion imaging.

PubMed

Evans, D H

2010-01-01

Colour flow imaging (CFI) is an ultrasound imaging technique whereby colour-coded maps of tissue velocity are superimposed on grey-scale pulse-echo images of tissue anatomy. The most widespread use of the method is to image the movement of blood through arteries and veins, but it may also be used to image the motion of solid tissue. The production of velocity information is technically more demanding than the production of the anatomical information, partly because the target of interest is often blood, which backscatters significantly less power than solid tissues, and partly because several transmit-receive cycles are necessary for each velocity estimate. This review first describes the various components of basic CFI systems necessary to generate the velocity information and to combine it with anatomical information. It then describes a number of variations on the basic autocorrelation technique, including cross-correlation-based techniques, power Doppler, Doppler tissue imaging, and three-dimensional (3D) Doppler imaging. Finally, a number of limitations of current techniques and some potential solutions are reviewed.

Adaptive Introgression across Species Boundaries in Heliconius Butterflies

PubMed Central

Pardo-Diaz, Carolina; Salazar, Camilo; Baxter, Simon W.; Merot, Claire; Figueiredo-Ready, Wilsea; Joron, Mathieu; McMillan, W. Owen; Jiggins, Chris D.

2012-01-01

It is widely documented that hybridisation occurs between many closely related species, but the importance of introgression in adaptive evolution remains unclear, especially in animals. Here, we have examined the role of introgressive hybridisation in transferring adaptations between mimetic Heliconius butterflies, taking advantage of the recent identification of a gene regulating red wing patterns in this genus. By sequencing regions both linked and unlinked to the red colour locus, we found a region that displays an almost perfect genotype by phenotype association across four species, H. melpomene, H. cydno, H. timareta, and H. heurippa. This particular segment is located 70 kb downstream of the red colour specification gene optix, and coalescent analysis indicates repeated introgression of adaptive alleles from H. melpomene into the H. cydno species clade. Our analytical methods complement recent genome scale data for the same region and suggest adaptive introgression has a crucial role in generating adaptive wing colour diversity in this group of butterflies. PMID:22737081

Performance assessment of Vita Easy Shade spectrophotometer on colour measurement of aesthetic dental materials.

PubMed

AlGhazali, N; Burnside, G; Smith, R W; Preston, A J; Jarad, F D

2011-12-01

Four different shades were used to produce 20 samples of resin-based composite and 20 samples of porcelain to evaluate the performance ability of an intra oral test spectrophotometer compared to a reference spectrophotometer. The absolute colour coordinates CIELAB values measured with both spectrophotometers were significantly different (p < 0.001). However, a high correlation was found (p < 0.001) despite the low concordance noticed. The colour difference deltaE* values calculated between different shades also were significantly different between both spectrophotometers (p < 0.05). Therefore, the Easy Shade can be used in dental practice and dental research with some limitations.

Modelling memory colour region for preference colour reproduction

NASA Astrophysics Data System (ADS)

Zeng, Huanzhao; Luo, Ronnier

2010-01-01

Colour preference adjustment is an essential step for colour image enhancement and perceptual gamut mapping. In colour reproduction for pictorial images, properly shifting colours away from their colorimetric originals may produce more preferred colour reproduction result. Memory colours, as a portion of the colour regions for colour preference adjustment, are especially important for preference colour reproduction. Identifying memory colours or modelling the memory colour region is a basic step to study preferred memory colour enhancement. In this study, we first created gamut for each memory colour region represented as a convex hull, and then used the convex hull to guide mathematical modelling to formulate the colour region for colour enhancement.

Effect of light-emitting diode colour temperature on magnifier reading performance of the visually impaired.

PubMed

Wolffsohn, James S; Palmer, Eshmael; Rubinstein, Martin; Eperjesi, Frank

2012-09-01

As light-emitting diodes become more common as the light source for low vision aids, the effect of illumination colour temperature on magnifier reading performance was investigated. Reading ability (maximum reading speed, critical print size, threshold near visual acuity) using Radner charts and subjective preference was assessed for 107 participants with visual impairment using three stand magnifiers with light emitting diode illumination colour temperatures of 2,700 K, 4,500 K and 6,000 K. The results were compared with distance visual acuity, prescribed magnification, age and the primary cause of visual impairment. Reading speed, critical print size and near visual acuity were unaffected by illumination colour temperature (p > 0.05). Reading metrics decreased with worsening acuity and higher levels of prescribed magnification but acuity was unaffected by age. Each colour temperature was preferred and disliked by a similar number of patients and was unrelated to distance visual acuity, prescribed magnification and age (p > 0.05). Patients had better near acuity (p = 0.002), critical print size (p = 0.034) and maximum reading speed (p < 0.001), and the improvement in near from distance acuity was greater (p = 0.004) with their preferred rather than least-liked colour temperature illumination. A range of colour temperature illuminations should be offered to all visually impaired individuals prescribed with an optical magnifier for near tasks to optimise subjective and objective benefits. © 2012 The Authors. Clinical and Experimental Optometry © 2012 Optometrists Association Australia.

Floral scent emitted by white and coloured morphs in orchids.

PubMed

Dormont, L; Delle-Vedove, R; Bessière, J-M; Schatz, B

2014-04-01

Polymorphism of floral signals, such as colour and odour, is widespread in flowering plants and often considered to be adaptive, reflecting various pollinator preferences for particular floral traits. Several authors have recently hypothesized that particular associations exist between floral colour and scent, which would result from shared biochemistry between these two floral traits. In this study, we compared the chemical composition of floral volatiles emitted by white- and purple-flowered morphs of three different orchid species, including two food-deceptive species (Orchis mascula and Orchis simia) and a food-rewarding species (Anacamptis coriophora fragrans). We found clear interspecific differences in floral odours. As expected from their pollination strategy, the two deceptive orchids showed high inter-individual variation of floral volatiles, whereas the food-rewarding A. c. fragrans showed low variation of floral scent. Floral volatiles did not differ overall between white- and coloured-flowered morphs in O. mascula and A. c. fragrans, while O. simia exhibited different volatile profiles between the two colour morphs. However, a detailed analysis restricted to benzenoid compounds (which are associated with the production of floral anthocyanin pigments) showed that white inflorescences emitted more volatiles of the shikimic pathway than coloured ones, both for O. mascula and O. simia. These results are consistent with the current hypothesis that shared biochemistry creates pleiotropic links between floral colour and scent. Whether intraspecific variation of floral signals actually affects pollinator attraction and influences the reproductive success of these orchids remains to be determined. Copyright © 2014 Elsevier Ltd. All rights reserved.

Visuospatial working memory for locations, colours, and binding in typically developing children and in children with dyslexia and non-verbal learning disability.

PubMed

Garcia, Ricardo Basso; Mammarella, Irene C; Tripodi, Doriana; Cornoldi, Cesare

2014-03-01

This study examined forward and backward recall of locations and colours and the binding of locations and colours, comparing typically developing children - aged between 8 and 10 years - with two different groups of children of the same age with learning disabilities (dyslexia in one group, non-verbal learning disability [NLD] in the other). Results showed that groups with learning disabilities had different visuospatial working memory problems and that children with NLD had particular difficulties in the backward recall of locations. The differences between the groups disappeared, however, when locations and colours were bound together. It was concluded that specific processes may be involved in children in the binding and backward recall of different types of information, as they are not simply the resultant of combining the single processes needed to recall single features. © 2013 The British Psychological Society.

Extrapolating from local ecological processes to genus-wide patterns in colour polymorphism in South African Protea

PubMed Central

Carlson, Jane E.; Holsinger, Kent E.

2015-01-01

Polymorphic traits are central to many fundamental discoveries in evolution, yet why they are found in some species and not others remains poorly understood. We use the African genus Protea—within which more than 40% of species have co-occurring pink and white floral colour morphs—to ask whether convergent evolution and ecological similarity could explain the genus-wide pattern of polymorphism. First, we identified environmental correlates of pink morph frequency across 28 populations of four species. Second, we determined whether the same correlates could predict species-level polymorphism and monomorphism across 31 species. We found that pink morph frequency increased with elevation in Protea repens and three section Exsertae species, increased eastward in P. repens, and increased with seed predation intensity in section Exsertae. For cross-species comparisons, populations of monomorphic pink species occurred at higher elevations than populations of monomorphic white species, and 18 polymorphic species spanned broader elevational gradients than 13 monomorphic species. These results suggest that divergent selection along elevational clines has repeatedly favoured polymorphism, and that more uniform selection in altitudinally restricted species may promote colour monomorphism. Our findings are, to our knowledge, the first to link selection acting within species to the presence and absence of colour polymorphism at broader phylogenetic scales. PMID:25876847

Colour pairs for constraining the age and metallicity of stellar populations

NASA Astrophysics Data System (ADS)

Li, Zhongmu; Han, Zhanwen

2008-04-01

Using a widely used stellar-population synthesis model, we study the possibility of using pairs of AB system colours to break the well-known stellar age-metallicity degeneracy and to give constraints on two luminosity-weighted stellar-population parameters (age and metallicity). We present the relative age and metallicity sensitivities of the AB system colours that relate to the u,B,g,V,r,R,i, I,z,J,H and K bands, and we quantify the ability of various colour pairs to break the age-metallicity degeneracy. Our results suggest that a few pairs of colours can be used to constrain the above two stellar-population parameters. This will be very useful for exploring the stellar populations of distant galaxies. In detail, colour pairs [(r-K), (u-R)] and [(r-K), (u-r)] are shown to be the best pairs for estimating the luminosity-weighted stellar ages and metallicities of galaxies. They can constrain two stellar-population parameters on average with age uncertainties less than 3.89 Gyr and metallicity uncertainties less than 0.34 dex for typical colour uncertainties. The typical age uncertainties for young populations (age < 4.6 Gyr) and metal-rich populations (Z >= 0.001) are small (about 2.26 Gyr) while those for old populations (age >= 4.6 Gyr) and metal-poor populations (Z < 0.001) are much larger (about 6.88 Gyr). However, the metallicity uncertainties for metal-poor populations (about 0.0024) are much smaller than for other populations (about 0.015). Some other colour pairs can also possibly be used for constraining the two parameters. On the whole, the estimation of stellar-population parameters is likely to be reliable only for early-type galaxies with small colour errors and globular clusters, because such objects contain less dust. In fact, no galaxy is totally dust-free and early-type galaxies are also likely have some dust [e.g. E(B- V) ~ 0.05], which can change the stellar ages by about 2.5 Gyr and metallicities (Z) by about 0.015. When we compare the photometric estimates with previous spectroscopic estimates, we find some differences, especially when comparing the stellar ages determined by two methods. The differences mainly result from the young populations of galaxies. Therefore, it is difficult to obtain the absolute values of stellar ages and metallicities, but the results are useful for obtaining some relative values. In addition, our results suggest that colours relating to both UBVRIJHK and ugriz magnitudes are much better than either UBVRIJHK or ugriz colours for breaking the well-known degeneracy. The results also show that the stellar ages and metallicities of galaxies observed by the Sloan Digital Sky Survey and the Two-Micron All-Sky Survey can be estimated via photometry data. The data are available at the Centre de Données astronomiques de Strabourg (CDS) or on request to the authors. E-mail: zhongmu.li@gmail.com

Colour and label evaluation of commercial pasteurised red juices and related drinks.

PubMed

Fallico, B; Arena, E; Chiappara, E; Ballistreri, G

2010-01-01

Despite growing demand by consumers for healthy beverages, artificial colours are still widely used. Levels of anthocyanins and artificial colours were determined by HPLC with UV-Vis detection in red orange juices and other red beverages (nectar, juice-based, health, carbonated and sports drinks). The contribution of pigments to the visible colour of the beverage was calculated. Red orange juice samples contained about 34 mg l(-1) of anthocyanins, which were responsible for about 92% of the visible colour. Red juice-based drinks, containing from 0% to 30% of red orange, berry, grape or pomegranate juices, had low levels of anthocyanins (about 7 mg l(-1)) and high levels of E129 (about 32 mg l(-1)), which were responsible for about 90.7% of the colour of these beverages. Red health drinks, enriched with vitamins and polyphenols, contained from 3% to 50% of red fruit juices. Also in this case the E129 levels were higher (about 22 mg l(-1)) than anthocyanins (about 9 mg l(-1)), and were responsible for the colour of the beverages (76.1%). High levels of artificial colours were found in red orange carbonated drinks, but in comparable amounts with those found in the other beverage samples, while anthocyanins were only present in trace amounts. Although all of the beverages claimed to contain red fruits on the labels, no correlation was found between the level of anthocyanins and the declared percentage of red fruits. These labels generally conformed with the requirements of the law, but food product labels can often be misleading to consumers about the real characteristics of the product.

A prospective study to assess the palatability of analgesic medicines in children.

PubMed

Smith, Coral June; Sammons, Helen M; Fakis, Apostolos; Conroy, Sharon

2013-03-01

This study examined children's opinions on the taste of three analgesic medicines: paracetamol, ibuprofen and codeine. Many medicines for children are unpleasant and unacceptable. Research has shown that children's taste preferences differ to adults, in whom palatability is often tested. Little British research exists on children's opinions on the palatability of medicines. This study aimed to address this gap in knowledge. Prospective observational study. Between May-September 2008, hospital inpatients aged 5-16 years rated the taste of required analgesics on a 100-mm visual analogue scale. This incorporated a 5-point facial hedonic scale. They were also asked their favourite flavour and colour for a medicine. A total of 159 children took part. Eighty-five males (53·5%) and 74 females (46·5%). The median age was 8 years (Inter-quartile range 6-11). The taste of ibuprofen was significantly preferred to paracetamol or codeine. Significant differences were observed depending if the medicine rated was taken first or second (for example pre-medication with paracetamol and ibuprofen). Younger children (5-8 years) were more likely to choose the extremes of the scale when grading than older children were. Preferred flavours on questioning were strawberry 44% and banana 17%. Favourite colours were pink 25·8% and red 20·8%, with girls more likely to choose pink and boys blue. Ibuprofen was the most palatable analgesic medicine tested. Children reported they preferred fruit flavours and colour was sex dependent. Nurses when administering two medicines together should consider giving the least palatable first, for example paracetamol before ibuprofen for pre-medication. © 2012 Blackwell Publishing Ltd.

Anaemia in pregnancy in the district of Anuradhapura, Sri Lanka--need for updating prevalence data and screening strategies.

PubMed

Chathurani, U; Dharshika, I; Galgamuwa, D; Wickramasinghe, N D; Agampodi, T C; Agampodi, S B

2012-09-01

To determine the prevalence of anaemia during pregnancy in Anuradhapura district and evaluate present screening methods for anaemia. Modified WHO 30 cluster sampling method with increased precision was used to estimate the prevalence of anaemia in the Anuradhapura district, Sri Lanka. Serum haemoglobin was measured using methemoglobin method. Clinical examination was carried out to evaluate the conjunctival method in anaemia screening. Values recorded from haemoglobin colour scale method used in the field antenatal clinics were collected. A total of 990 pregnant women participated in the study. In the first, second and third trimesters, prevalence of anaemia was 7.6%, 19.7% and 19.3% respectively. Gestational age adjusted anaemia prevalence among pregnant women in this study population was 14.1% (95% CI 12.0-16.4%). Mean and median haemoglobin concentration of the study sample was 11.8g/dL (SD 1.02g/dl and IQR 11.2-12.5g/dl). Among anaemic pregnant women, average values for Mean Corpuscular Volume (MCV), Mean Corpuscular Haemoglobin (MCH), and Mean Corpuscular Haemoglobin Concentration (MCHC) were, 82.9 fl (SD 11.5), 27.6 (SD-3.6) pg/cell and 32.9g/dl (SD 1.8) respectively. Sensitivity and specificity of haemoglobin colour scale method was 50% (95% CI 29.0-71.0%) and 76.3% (95% CI 66.9-83.7%) respectively. Sensitivity and specificity of conjunctival method in detecting anaemia during pregnancy was 18.8% (95% CI 11.9-28.4) and 69.3% (95% CI 58.2- 78.6%). Prevalence of anaemia in the district of Anuradhapura was less than 50% of the estimated prevalence for Sri Lanka. Both haemoglobin colour scale and conjunctival method were having low validity in detecting anaemia in pregnancy.

New opportunities in planetary geomorphology: an assessment of the capabilities of the Colour and Stereo Surface Imaging System (CaSSIS) on The Exomars Trace Gas Orbiter through Image Simulation.

NASA Astrophysics Data System (ADS)

Tornabene, Livio Leonardo; Seelos, Frank; Pommerol, Antoine; Thomas, Nick; Caudill, Christy; Conway, Susan J.

2017-04-01

The Colour and Stereo Surface Imaging System (CaSSIS) is a full-colour visible to near-infrared (VNIR) bi-directional pushframe stereo camera onboard the ExoMars 2016 Trace Gas Orbiter (TGO). For more details on ExoMars TGO and its payload, please see [4], and for the CaSSIS instrument see [1]. For details on the first Mars Capture Orbit (MCO)-acquired CaSSIS stereo images and preliminary 3D reconstructions from them [5]. CaSSIS will provide full-colour, stereo and repeat imaging spanning different times of day and covering all seasons. Such images will be used to address the following objectives: 1) characterizing possible [surface/subsurface] sources for methane and other trace gases; 2) investigating dynamic surface processes that may contribute to atmospheric gases; and 3) certifying and characterizing candidate landing site safety and hazards (e.g., rocks, slopes, etc.). Here we present a summary, and some highlights, based on the creation and analysis of simulated CaSSIS image cubes [see 2, 3]. We generated simulated images that are spatially (4.6 m/px) and spectrally (4-bands) consistent with CaSSIS from existing Mars Reconnaissance Orbiter (MRO) datasets. Simulated CaSSIS colours were generated from hyperspectral VNIR (S-detector) data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) after the methods of [6], which were then combined with spatially oversampled and resampled 32-bit calibrated I/F images from the Context Camera (CTX) and High Resolution Imaging Science Experiment (HiRISE) [2, 3]. For more of the details on the simulation process and the various products produced please see [2, 3]. Our simulations show that such colour coverage will be particularly valuable towards facilitating and enhancing seasonal process and change detection studies. For example, a simulation image of Gasa crater demonstrates exactly how additional colour context would facilitate gully change detections that can be subtle and difficult to detect in single-band images, or when missed by the HiRISE colour swath. Another result based on our colour analysis includes, excellent separation of ferrous- and ferric-bearing surface materials provided by band ratio colour composite images utilizing the two NIR bands of CaSSIS (3RED, 4NIR). These images will be particularly useful for associating CaSSIS colour units with spectral units defined by orbiting spectrometers (e.g., CRISM), and thereby extend spectral mapping to CaSSIS spatial scales. This will particularly be beneficial for landing sites where it is difficult to achieve continuous colour coverage with HiRISE. Our analysis shows that dune movement can be detected at the scale of CaSSIS, given a long enough baseline. Other results include resolving: 1) larger individual or sets of Recurring Slope Lineae (RSL), 2) small impacts (including ice excavators), and 3) surface changes associated with landers/rovers (NOTE: lander/rovers and their tracks are not resolvable). References: [1] Thomas N. et al. (2016), submitted to SSR. [2] Tornabene L. et al. (2017), submitted to SSR. [3] Tornabene L. et al. (2016) LPSC 47, Abstract #2695. [4] Vago J. et al. (2015) SSR, 49 518-528. [5] Cremonese G. et al. (2017) LPSC 48. [6] Seelos F. et al. (2011) AGU Fall, vol. 23, Abstract #1714. [7] Delamere A. et al. (2010), Icarus, 205, 38-52. Acknowledgements: The authors wish to thank the spacecraft and instrument engineering teams for the successful completion of the instrument. CaSSIS is a project of the University of Bern and funded through the Swiss Space Office via ESA's PRODEX programme. The instrument hardware development was also supported by the Italian Space Agency (ASI) (ASI-INAF agreement no.I/018/12/0), INAF/Astronomical Observatory of Padova, and the Space Research Center (CBK) in Warsaw. Support from SGF (Budapest), the University of Arizona Lunar and Planetary Laboratory, and NASA are also gratefully acknowledged. The lead author also acknowledges personal Canadian-based support from the Canadian Space Agency (CSA), and the NSERC DG programme.

Prediction of a nail polish colour applied on a nail.

PubMed

Monpeurt, C; Cinotti, E; Razafindrakoto, J; Rubegni, P; Fimiani, M; Perrot, J L; Hebert, M

2018-02-01

The colour of a nail polish varies according to the nail on which it is applied. The objective of this study was to predict the colour of the nail polish on a given nail and to study how the colour varies depending on the nail polish thickness. Six nail polishes were applied in one, two and three layers on the nails of one subject, thus forming eighteen samples. The spectral reflectances of the eighteen nail polishes applied on the nails with different thicknesses were obtained by spectrophotometry. The spectral reflectances of the nails without polish were also measured using the same technique. The thicknesses of nail polishes were measured by high-definition optical coherence tomography (HD-OCT). Then, to determine the physical parameters of the nail polish itself, we applied the six nail polishes on an opacity drawdown chart and we measured the spectral reflectance and the thickness of each patch using spectrophotometry and HD-OCT, respectively. The Kubelka-Munk theory was used to get the predicted spectral reflectance of the nail polish applied on the nail according to the polish thickness by knowing the parameter of the polish itself and the spectral reflectance of the nail. The predicted spectral reflectances were finally compared with those measured directly on the nails. The predicted spectral reflectances were rather close to measured ones. Consequently, knowing the colour of the nail without polish and the optical parameters of the nail polish itself, we can estimate the colour of the nail polish applied on the nail depending on its thickness. Our study showed that the Kubelka-Munk theory can be used to predict the nail polish colour. The ability to predict the real colour of a nail polish applied on a nail could help a nail polish manufacturer to improve his polish formulae in order to obtain a precise colour. © 2017 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

True and false memory for colour names versus actual colours: support for the visual distinctiveness heuristic in memory for colour information.

PubMed

Eslick, Andrea N; Kostic, Bogdan; Cleary, Anne M

2010-06-01

In a colour variation of the Deese-Roediger-McDermott (DRM) false memory paradigm, participants studied lists of words critically related to a nonstudied colour name (e.g., "blood, cherry, scarlet, rouge ... "); they later showed false memory for the critical colour name (e.g., "red"). Two additional experiments suggest that participants generate colour imagery in response to such colour-related DRM lists. First, participants claim to experience colour imagery more often following colour-related than standard non-colour-related DRM lists; they also rate their colour imagery as more vivid following colour-related lists. Second, participants exhibit facilitative priming for critical colours in a dot selection task that follows words in the colour-related DRM list, suggesting that colour-related DRM lists prime participants for the actual critical colours themselves. Despite these findings, false memory for critical colour names does not extend to the actual colours themselves (font colours). Rather than leading to source confusion about which colours were self-generated and which were studied, presenting the study lists in varied font colours actually worked to reduce false memory overall. Results are interpreted within the framework of the visual distinctiveness hypothesis.

Comparative Studies on Dyeability with Direct, Acid and Reactive Dyes after Chemical Modification of Jute with Mixed Amino Acids Obtained from Extract of Waste Soya Bean Seeds

NASA Astrophysics Data System (ADS)

Bhaumik, Nilendu Sekhar; Konar, Adwaita; Roy, Alok Nath; Samanta, Ashis Kumar

2017-12-01

Jute fabric was treated with mixed natural amino acids obtained from waste soya bean seed extract for chemical modification of jute for its cataionization and to enhance its dyeability with anionic dyes (like direct, reactive and acid dye) as well enabling soya modified jute for salt free dyeing with anionic reactive dyes maintaining its eco-friendliness. Colour interaction parameters including surface colour strength were assessed and compared for both bleached and soya-modified jute fabric for reactive dyeing and compared with direct and acid dye. Improvement in K/S value (surface colour strength) was observed for soya-modified jute even in absence of salt applied in dye bath for reactive dyes as well as for direct and acid dyes. In addition, reactive dye also shows good dyeability even in acid bath in salt free conditions. Colour fastness to wash was evaluated for bleached and soya-modified jute fabric after dyeing with direct, acid and reactive dyes are reported. Treatment of jute with soya-extracted mixed natural amino acids showed anchoring of some amino/aldemine groups on jute cellulosic polymer evidenced from Fourier Transform Infra-Red (FTIR) Spectroscopy. This amino or aldemine group incorporation in bleached jute causes its cationization and hence when dyed in acid bath for reactive dye (instead of conventional alkali bath) showed dye uptake for reactive dyes. Study of surface morphology by Scanning Electron Microscopy (SEM) of said soya-modified jute as compared to bleached jute was studied and reported.

Honeybees in a virtual reality environment learn unique combinations of colour and shape.

PubMed

Rusch, Claire; Roth, Eatai; Vinauger, Clément; Riffell, Jeffrey A

2017-10-01

Honeybees are well-known models for the study of visual learning and memory. Whereas most of our knowledge of learned responses comes from experiments using free-flying bees, a tethered preparation would allow fine-scale control of the visual stimuli as well as accurate characterization of the learned responses. Unfortunately, conditioning procedures using visual stimuli in tethered bees have been limited in their efficacy. In this study, using a novel virtual reality environment and a differential training protocol in tethered walking bees, we show that the majority of honeybees learn visual stimuli, and need only six paired training trials to learn the stimulus. We found that bees readily learn visual stimuli that differ in both shape and colour. However, bees learn certain components over others (colour versus shape), and visual stimuli are learned in a non-additive manner with the interaction of specific colour and shape combinations being crucial for learned responses. To better understand which components of the visual stimuli the bees learned, the shape-colour association of the stimuli was reversed either during or after training. Results showed that maintaining the visual stimuli in training and testing phases was necessary to elicit visual learning, suggesting that bees learn multiple components of the visual stimuli. Together, our results demonstrate a protocol for visual learning in restrained bees that provides a powerful tool for understanding how components of a visual stimulus elicit learned responses as well as elucidating how visual information is processed in the honeybee brain. © 2017. Published by The Company of Biologists Ltd.

The iris signal: blue periphery, tan collaret and freckles pattern - strong indicators for epidermal skin cancer in South-Eastern Europe.

PubMed

Grigore, M; Furtunescu, F; Minca, D; Costache, M; Garbe, C; Simionescu, O

2018-03-10

Eye and skin share the embryological origin. Both are established risk factors in epidermal skin cancer. There are few reports using iris colour classification scales, most of them analyse colour in general or are too complex to use in daily practice. To investigate which iris colour pattern is associated with epidermal skin cancer in a S-E European Caucasian population. A case-control study was conducted on 480 patients: 229 skin cancers patients and 251 controls (dermatological patients free of skin cancers) admitted in two medical clinics of Dermatology in Bucharest, between October 2011 and May 2014. High-resolution iris photographs were taken for each patient. Three parameters of the iris were analysed individually and in association patterns for each patient: periphery, collaret and freckles. The most frequent iris colour pattern associated with epidermal skin cancer was blue periphery with light brown collaret and freckles present. In terms of individual parameters, the strongest indicators for skin cancer patients were blue periphery and blue collaret. The results of this study sustain the hypothesis that blue periphery with light brown collaret and freckles iris pattern is a reliable phenotypic marker for epidermal skin cancer. The results of this study differ from previous reports in which skin cancer risk was associated with a homogeneous blue iris. We account these differences in the characteristics of the recruited patients (S-E European, skin type II and III). The assessment of iris colour patterns is an easy and inexpensive detection tool in skin cancer risk assessment. © 2018 European Academy of Dermatology and Venereology.

Hemispherical Brillouin zone imaging of a diamond-type biological photonic crystal

PubMed Central

Wilts, Bodo D.; Michielsen, Kristel; De Raedt, Hans; Stavenga, Doekele G.

2012-01-01

The brilliant structural body colours of many animals are created by three-dimensional biological photonic crystals that act as wavelength-specific reflectors. Here, we report a study on the vividly coloured scales of the diamond weevil, Entimus imperialis. Electron microscopy identified the chitin and air assemblies inside the scales as domains of a single-network diamond (Fd3m) photonic crystal. We visualized the topology of the first Brillouin zone (FBZ) by imaging scatterometry, and we reconstructed the complete photonic band structure diagram (PBSD) of the chitinous photonic crystal from reflectance spectra. Comparison with calculated PBSDs indeed showed a perfect overlap. The unique method of non-invasive hemispherical imaging of the FBZ provides key insights for the investigation of photonic crystals in the visible wavelength range. The characterized extremely large biophotonic nanostructures of E. imperialis are structurally optimized for high reflectance and may thus be well suited for use as a template for producing novel photonic devices, e.g. through biomimicry or direct infiltration from dielectric material. PMID:22188768

Recharacterization of Rhinophis dorsimaculatus Deraniyagala, 1941 (Serpentes: Uropeltidae), including description of new material.

PubMed

Gower, David J; Wickramasinghe, L J Mendis

2016-08-29

The Sri Lankan uropeltid (shieldtail) snake Rhinophis dorsimaculatus Deraniyagala, 1941 was described originally from two specimens that were subsequently lost. The small amount of previously published data and lack of published colour photographs made this one of South Asia's most poorly known snake species, and this resulted in at least one instance of taxonomic misidentification. An additional 10 specimens from a historical collection from the vicinity of the type locality recently came to light. This material is reviewed and documented and the species recharacterized. An additional locality for the species is reported. The newly reported material helps to corroborate the taxonomic validity and distinctiveness of Rhinophis dorsimaculatus. The species is readily distinguished from congeners by having 227 or more ventral scales; a large, dorsally carinate rostral shield; posterior margins of paired anals that are largely separated by the posteriormost ventral scale; and a distinctive colour pattern with bilaterally asymmetrical dark blotches within a broad, pale middorsal stripe and regularly punctate flanks.

MUFASA: the strength and evolution of galaxy conformity in various tracers

NASA Astrophysics Data System (ADS)

Rafieferantsoa, Mika; Davé, Romeel

2018-03-01

We investigate galaxy conformity using the MUFASA cosmological hydrodynamical simulation. We show a bimodal distribution in galaxy colour with radius, albeit with too many low-mass quenched satellite galaxies compared to observations. MUFASA produces conformity in observed properties such as colour, specific star formation rate (sSFR), and H I content, i.e. neighbouring galaxies have similar properties. We see analogous trends in other properties such as in environment, stellar age, H2 content, and metallicity. We introduce quantifying conformity using S(R), measuring the relative difference in upper and lower quartile properties of the neighbours. We show that low-mass and non-quenched haloes have weak conformity (S(R)≲ 0.5) extending to large projected radii R in all properties, while high-mass and quenched haloes have strong conformity (S(R)˜ 1) that diminishes rapidly with R and disappears at R ≳ 1 Mpc. S(R) is strongest for environment in low-mass haloes, and sSFR (or colour) in high-mass haloes, and is dominated by one-halo conformity with the exception of H I in small haloes. Metallicity shows a curious anticonformity in massive haloes. Tracking the evolution of conformity for z = 0 galaxies back in time shows that conformity broadly emerges as a late-time (z ≲ 1) phenomenon. However, for fixed halo mass bins, conformity is fairly constant with redshift out to z ≳ 2. These trends are consistent with the idea that strong conformity only emerges once haloes grow above MUFASA's quenching mass scale of ˜1012 M⊙. A quantitative measure of conformity in various properties, along with its evolution, thus represents a new and stringent test of the impact of quenching on environment within current galaxy formation models.

Galaxy And Mass Assembly (GAMA): colour- and luminosity-dependent clustering from calibrated photometric redshifts

NASA Astrophysics Data System (ADS)

Christodoulou, L.; Eminian, C.; Loveday, J.; Norberg, P.; Baldry, I. K.; Hurley, P. D.; Driver, S. P.; Bamford, S. P.; Hopkins, A. M.; Liske, J.; Peacock, J. A.; Bland-Hawthorn, J.; Brough, S.; Cameron, E.; Conselice, C. J.; Croom, S. M.; Frenk, C. S.; Gunawardhana, M.; Jones, D. H.; Kelvin, L. S.; Kuijken, K.; Nichol, R. C.; Parkinson, H.; Pimbblet, K. A.; Popescu, C. C.; Prescott, M.; Robotham, A. S. G.; Sharp, R. G.; Sutherland, W. J.; Taylor, E. N.; Thomas, D.; Tuffs, R. J.; van Kampen, E.; Wijesinghe, D.

2012-09-01

We measure the two-point angular correlation function of a sample of 4289 223 galaxies with r < 19.4 mag from the Sloan Digital Sky Survey (SDSS) as a function of photometric redshift, absolute magnitude and colour down to Mr - 5 log h = -14 mag. Photometric redshifts are estimated from ugriz model magnitudes and two Petrosian radii using the artificial neural network package ANNz, taking advantage of the Galaxy And Mass Assembly (GAMA) spectroscopic sample as our training set. These photometric redshifts are then used to determine absolute magnitudes and colours. For all our samples, we estimate the underlying redshift and absolute magnitude distributions using Monte Carlo resampling. These redshift distributions are used in Limber's equation to obtain spatial correlation function parameters from power-law fits to the angular correlation function. We confirm an increase in clustering strength for sub-L* red galaxies compared with ˜L* red galaxies at small scales in all redshift bins, whereas for the blue population the correlation length is almost independent of luminosity for ˜L* galaxies and fainter. A linear relation between relative bias and log luminosity is found to hold down to luminosities L ˜ 0.03L*. We find that the redshift dependence of the bias of the L* population can be described by the passive evolution model of Tegmark & Peebles. A visual inspection of a random sample from our r < 19.4 sample of SDSS galaxies reveals that about 10 per cent are spurious, with a higher contamination rate towards very faint absolute magnitudes due to over-deblended nearby galaxies. We correct for this contamination in our clustering analysis.

Visualising uncertainty: interpreting quantified geoscientific inversion outputs for a diverse user community.

NASA Astrophysics Data System (ADS)

Reading, A. M.; Morse, P. E.; Staal, T.

2017-12-01

Geoscientific inversion outputs, such as seismic tomography contour images, are finding increasing use amongst scientific user communities that have limited knowledge of the impact of output parameter uncertainty on subsequent interpretations made from such images. We make use of a newly written computer application which enables seismic tomography images to be displayed in a performant 3D graphics environment. This facilitates the mapping of colour scales to the human visual sensorium for the interactive interpretation of contoured inversion results incorporating parameter uncertainty. Two case examples of seismic tomography inversions or contoured compilations are compared from the southern hemisphere continents of Australia and Antarctica. The Australian example is based on the AuSREM contoured seismic wavespeed model while the Antarctic example is a valuable but less well constrained result. Through adjusting the multiple colour gradients, layer separations, opacity, illumination, shadowing and background effects, we can optimise the insights obtained from the 3D structure in the inversion compilation or result. Importantly, we can also limit the display to show information in a way that is mapped to the uncertainty in the 3D result. Through this practical application, we demonstrate that the uncertainty in the result can be handled through a well-posed mapping of the parameter values to displayed colours in the knowledge of what is perceived visually by a typical human. We found that this approach maximises the chance of a useful tectonic interpretation by a diverse scientific user community. In general, we develop the idea that quantified inversion uncertainty can be used to tailor the way that the output is presented to the analyst for scientific interpretation.

Map presentation of changes in Europe's artificial surfaces for the periods 1990-2000 and 2000-2006

NASA Astrophysics Data System (ADS)

Feranec, Jan; Soukup, Tomas

2013-06-01

The landscapes of the world are constantly changing under the influence of human activities leading to the growth of artificial surfaces. The covering of soil by artificial surfaces is referred to as soil sealing. Aerial and satellite images or data derived from them (for instance CORINE land cover — CLC data used here) provide important information that makes it possible to assess the occurrence, area and rate of soil sealing. As the term sealed soil cannot be wholly identified with the content of the appropriate CLC classes, the term land cover flow urbanization (LCFU) will be used here. The essence of this study is the demonstration and documentation of the trends of the LCFU in Europe for the periods 1990-2000 and 2000-2006 on a single map. This may contribute to a better spatial awareness of the ongoing transformation of landscape under the effects of human activities in an pan-European context. Changes in the LCFU can be seen on a map, compiled from 3 × 3 km squares at an all-European scale, using colours and their hues, to fulfil the role both of identification and classification. The colour method employed makes it possible to perceive three groups of LCFU changes on two time horizons, that is, whether the rate of LCFU in 2000-2006 increased or remained the same (hues of red); or dropped compared to the 1990-2000 period (hues of light to dark blue). The third group represents the LCFU with rates higher or lower than the average (countries with changes recorded in only one time horizon are presented in dark and light magenta colours).

Does colour preference have a role in colour term acquisition?

PubMed

Pitchford, Nicola J; Davis, Emma E; Scerif, Gaia

2009-11-01

A developmental association exists between colour preference and emerging colour term acquisition in young children. Colour preference might influence colour term acquisition by directing attention towards or away from a particular colour, making it more or less memorable. To investigate the role that colour preference may have in the acquisition of colour terms, experimental tasks of colour preference, discrimination, attention, memory, and new colour term learning, were given to three groups of participants (preschool children; primary school children; and adults). Each task utilized the same colour stimuli, which were four computer-simulated colours, matched perceptually to four different Munsell chips, drawn from the same colour category. Three colours varied systematically from an anchor colour (10PB 4/8) only in saturation (10PB 4/4), luminance (10PB 6/8), or hue (5P 4/8). Results showed that within-category colour preferences emerged with age, and that when established within individuals, most preferred colours were named significantly more accurately than least preferred colours, although this association did not appear to be mediated directly by attention or memory. Rather, perceptual saliency was shown to have a mediating role, to some extent, in determining the relationship between colour preference and the cognitive processing of colour.

The effect of high-pressure processing on colour, bioactive compounds, and antioxidant activity in smoothies during refrigerated storage.

PubMed

Andrés, Víctor; Villanueva, María J; Tenorio, María D

2016-02-01

The effects of high-pressure processing--HPP--(450 and 600 MPa/3 min/20 °C) on the colour, carotenoids, ascorbic acid, polyphenols and antioxidant activity (FRAP and DPPH) of a smoothie were compared to thermal processing (80 °C/3 min). Stability during 45 days at 4 °C was also evaluated. HPP samples showed slight differences (p < 0.05) in colour compared to untreated smoothies. Both HPP significantly increased the extractability of lycopene, β-carotene and polyphenols compared to untreated samples. After HPP, ascorbic acid was retained by more than 92% of the initial content. The best results for antioxidant activity were obtained when HPP was applied at 600 MPa. FRAP and DPPH showed a high correlation with ascorbic acid (R(2) = 0.7135 and 0.8107, respectively) and polyphenolic compounds (R(2) = 0.6819 and 0.6935, respectively), but not with total carotenoids. Changes in bioactive compounds during the storage period were lower in the HPP smoothie than in the thermal-treated sample. Copyright © 2015 Elsevier Ltd. All rights reserved.

The restriction of grazing duration does not compromise lamb meat colour and oxidative stability.

PubMed

Luciano, G; Biondi, L; Pagano, R I; Scerra, M; Vasta, V; López-Andrés, P; Valenti, B; Lanza, M; Priolo, A; Avondo, M

2012-09-01

Over 72 days, 33 lambs were fed: concentrates in stall (S), grass at pasture for 8 hours (8 h), or grass at pasture for 4 hours in the afternoon (4h-PM). The 4h-PM treatment did not affect the carcass yield compared to the 8h treatment. Meat colour development after blooming was unaffected by the treatments. The 4 h-PM treatment increased the proportion of polyunsaturated fatty acids (PUFA; P<0.0005) and of the highly peroxidizable fatty acids (HP-PUFA; P<0.001) in meat compared to the 8h treatment. The S treatment increased lipid oxidation (higher TBARS values) and impaired colour stability (higher H* values) of meat over storage compared to the 8h and 4 h-PM treatments (P<0.0005 and P=0.003, respectively). No difference in meat oxidative stability was found between the 8h and the 4h-PM treatments. In conclusion, growing lambs can tolerate a restriction of grazing duration without detrimental effects on performances and meat oxidative stability. Copyright © 2012. Published by Elsevier Ltd.

Colour discrimination, colour naming and colour preferences among individuals with Alzheimer's disease.

PubMed

Wijk, H; Berg, S; Sivik, L; Steen, B

1999-12-01

To study the ability of colour naming, colour discrimination and colour preference in Alzheimer's disease (AD). Descriptive, consecutive sample. Fifty subjects >65 years with AD. Testing colour discrimination, colour naming and colour preferences. Ability to detect colour differences in the yellow, red, blue and green areas, ability to assign a name to 22 colour samples, ability to rank seven colours in order of preference. Discrimination ability was significantly better in the yellow and red area and for lightness variations. Cognitive decline had a significant impact on naming mixed colours and using elaborate colour names. Severity of dementia did not affect the preference rank order of colours. Ability to discriminate is affected in AD, with most errors in the blue and green area. Naming colours shows a cognitive decline. Preferences for colour are stable despite the disease. Copyright 1999 John Wiley & Sons, Ltd.

A colour image reproduction framework for 3D colour printing

NASA Astrophysics Data System (ADS)

Xiao, Kaida; Sohiab, Ali; Sun, Pei-li; Yates, Julian M.; Li, Changjun; Wuerger, Sophie

2016-10-01

In this paper, the current technologies in full colour 3D printing technology were introduced. A framework of colour image reproduction process for 3D colour printing is proposed. A special focus was put on colour management for 3D printed objects. Two approaches, colorimetric colour reproduction and spectral based colour reproduction are proposed in order to faithfully reproduce colours in 3D objects. Two key studies, colour reproduction for soft tissue prostheses and colour uniformity correction across different orientations are described subsequently. Results are clear shown that applying proposed colour image reproduction framework, performance of colour reproduction can be significantly enhanced. With post colour corrections, a further improvement in colour process are achieved for 3D printed objects.

Col-OSSOS: A new ugrJ taxonomy for trans-Neptunian objects

NASA Astrophysics Data System (ADS)

Fraser, Wesley Cristopher; Bannister, Michele T.; Marsset, Michael; Pike, Rosemary E.; Schwamb, Megan E.; Kavelaars, J. J.; Benecchi, Susan D.; Delsanti, Audrey; Lehner, Matt J.; Wang, Shiang-Yu; Thirouin, Audrey; Guilbert-Lepoutre, Aurelie; Peixinho, Nuno; Vernazza, Pierre

2016-10-01

The surfaces of trans-Neptunian objects (TNOs) are poorly understood. Very little has been discerned about the compositions of most small TNOs. In recent years however, some concrete knowledge about the surface colour distribution of TNOs has come to light. It is now generally accepted that small TNOs fall into at least three classes of object based on their surface colours and albedo. Despite nearly two decades of gathering TNO surface information however, a taxonomy has still not been agreed upon. From Col-OSSOS u, g, r, and J photometry, we find significantly different clustering of (u-g) colour in the optically red, dynamically cold TNOs as compared to similarly optically coloured dynamically excited TNOs. One of the goals of the Colours of the Outer Solar System Origins Survey is the development of a robust TNO taxonomy. This 4 year program which started in 2014B is simultaneously using the Gemini-North and Canada-France-Hawaii telescopes to gather near simultaneous u, g, r, and J spectral photometry of all targets in the Outer Solar System Origins Survey (OSSOS) brighter than r'=23.6 (120 expected). The focus of Col-OSSOS is completeness and consistency, with the same SNR=25 being reached in all bands, for all targets brighter than our depth limit. Col-OSSOS will provide the first brightness-complete, compositional-dynamical map of the Outer Solar System, from which key hypotheses about the Solar System's cosmogony can be tested. After an overview of the survey's design and techniques, we will present the observed colours from the first complete block. Even with just ~30 targets, the precise photometry afforded by Col-OSSOS has already revealed the existence of 3 separate TNO taxons or classes, which become obvious when their (u-g), (g-r), and (r-J) colours are considered together. In particular, the so-called cold classical TNOs, which stand out because of their dynamically quiescent orbits, while possessing similar (g-r) and (r-J) colours as other red TNOs, exhibit extremely red (u-g) colours, roughly 0.5 magnitudes redder than the typical (u-g) of the red dynamically excited objects. These classes appear to exhibit a continuum in colour, rather than occupying similar mean colours for all class members.

Links between global and local shape perception, coloured backgrounds, colour discrimination, and non-verbal IQ.

PubMed

Dore, Patricia; Dumani, Ardian; Wyatt, Geddes; Shepherd, Alex J

2018-03-16

This study explored associations between local and global shape perception on coloured backgrounds, colour discrimination, and non-verbal IQ (NVIQ). Five background colours were chosen for the local and global shape tasks that were tailored for the cone-opponent pathways early in the visual system (cardinal colour directions: L-M, loosely, reddish-greenish; and S-(L + M), or tritan colours, loosely, blueish-yellowish; where L, M and S refer to the long, middle and short wavelength sensitive cones). Participants also completed the Farnsworth-Munsell 100-hue test (FM100) to determine whether performance on the local and global shape tasks correlated with colour discrimination overall, or with performance on the L-M and tritan subsets of the FM100 test. Overall performance on the local and global shape tasks did correlate with scores on the FM100 tests, despite the colour of the background being irrelevant to the shape tasks. There were also significantly larger associations between scores for the L-M subset of the FM100 test, compared to the tritan subset, and accuracy on some of the shape tasks on the reddish, greenish and neutral backgrounds. Participants also completed the non-verbal components of the WAIS and the SPM+ version of Raven's progressive matrices, to determine whether performance on the FM100 test, and on the local and global shape tasks, correlated with NVIQ. FM100 scores correlated significantly with both WAIS and SPM+ scores. These results extend previous work that has indicated FM100 performance is not purely a measure of colour discrimination, but also involves aspects of each participant's NVIQ, such as the ability to attend to local and global aspects of the test, part-whole relationships, perceptual organisation and good visuomotor skills. Overall performance on the local and global shape tasks correlated only with the WAIS scores, not the SPM+. These results indicate that those aspects of NVIQ that engage spatial comprehension of local-global relationships and manual manipulation (WAIS), rather than more abstract reasoning (SPM+), are related to performance on the local and global shape tasks. Links are presented between various measures of NVIQ and performance on visual tasks, but they are currently seldom addressed in studies of either shape or colour perception. Further studies to explore these issues are recommended. Copyright © 2018 Elsevier Ltd. All rights reserved.

Biofouling potential and material reactivity in a simulated water distribution network supplied with stormwater recycled via managed aquifer recharge.

PubMed

Gonzalez, Dennis; Tjandraatmadja, Grace; Barry, Karen; Vanderzalm, Joanne; Kaksonen, Anna H; Dillon, Peter; Puzon, Geoff J; Sidhu, Jatinder; Wylie, Jason; Goodman, Nigel; Low, Jason

2016-11-15

The injection of stormwater into aquifers for storage and recovery during high water demand periods is a promising technology for augmenting conventional water reserves. Limited information exists regarding the potential impact of aquifer treated stormwater in distribution system infrastructure. This study describes a one year pilot distribution pipe network trial to determine the biofouling potential for cement, copper and polyvinyl chloride pipe materials exposed to stormwater stored in a limestone aquifer compared to an identical drinking water rig. Median alkalinity (123 mg/L) and colour (12 HU) in stormwater was significantly higher than in drinking water (82 mg/L and 1 HU) and pipe discolouration was more evident for stormwater samples. X-ray Diffraction and Fluorescence analyses confirmed this was driven by the presence of iron rich amorphous compounds in more thickly deposited sediments also consistent with significantly higher median levels of iron (∼0.56 mg/L) in stormwater compared to drinking water (∼0.17 mg/L). Water type did not influence biofilm development as determined by microbial density but faecal indicators were significantly higher for polyvinyl chloride and cement exposed to stormwater. Treatment to remove iron through aeration and filtration would reduce the potential for sediment accumulation. Operational and verification monitoring parameters to manage scaling, corrosion, colour, turbidity and microbial growth in recycled stormwater distribution networks are discussed. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

Analysis of Wilhelm Ostwald's "Colour Organ" with Raman microspectroscopy

NASA Astrophysics Data System (ADS)

Bridarolli, Alexandra; Atak, Sefkan; Herm, Christoph

2016-11-01

The "Scientific Colour Organ" is a collection of 680 pigment powders, created by the chemist Wilhelm Ostwald in 1925 as a means to represent his colour system. Today, it remains a leading part of colour theory. Analysis of these materials was undertaken to understand how the colour system was realised and to gain indications for preservation of the collection to which it belongs. Dispersive Raman microspectroscopy was applied directly to the powders, as well as using alternative techniques to suppress fluorescence. Barium sulphate was detected in all of the samples with one exception. Portable X-ray fluorescence revealed that this compound was a constituent of lithopone pigment. Raman spectroscopy furthermore revealed synthetic ultramarine (C.I. PB 29) as well as six different synthetic organic pigments and dyes (C.I. PY3; C.I. PO5; C.I. PR81:1; C.I. PV2 and two different triarylmethane dyes). Thin-layer chromatography was applied to determine the exact combination of dyes causing the gradual change in colour of each powder compared to the adjacent samples. With the exception of triarylmethane, the synthetic organic dyes could be identified with Raman spectroscopy directly on the chromatographic plate. The efficiency of thin-layer chromatography combined with Raman spectroscopy for identification of organic pigments could thus be shown. X-ray fluorescence indicated the presence of tungsten-molybdenum lakes in some samples. Comparison of the analytical results to information published by Oswald in 1917 showed that he switched to more light-stable synthetic organic pigments used for his "Scientific Colour Organ".

Male courtship preferences demonstrate discrimination against allopatric colour morphs in a cichlid fish

PubMed Central

Zoppoth, P; Koblmüller, S; Sefc, K M

2013-01-01

Whether premating isolation is achieved by male-specific, female-specific or sex-independent assortative preferences often depends on the underlying evolutionary processes. Here we test mate preferences of males presented with females of different allopatric colour variants of the cichlid fish Tropheus sp., a Lake Tanganyika endemic with rich geographical colour pattern variation, in which the strength of sexual isolation varies between populations. We conducted two-way mate choice experiments to compare behaviour of males of a red-bodied morph (population Moliro) towards females from their own population with behaviour towards females from four allopatric populations at different stages of phylogenetic and phenotypic divergence. Males courted same-population females significantly more intensely than females of other populations, and reduced their heteromorphic courtship efforts both with increasing genetic and increasing phenotypic distinctness of the females. In particular, females of a closely related red-bodied population received significantly more courtship than either genetically distinct, similarly coloured females (‘Kirschfleck’ morph) or genetically related, differently coloured females (‘yellow-blotch’ morph), both of which were courted similarly. Genetically and phenotypically distinct females (Tropheus polli) were not courted at all. Consistent with previous female-choice experiments, female courtship activity also decreased with increasing genetic distance from the males’ population. Given successful experimental and natural introgression between colour morphs and the pervasive allopatry of related variants, we consider it unlikely that assortative preferences of both sexes were driven by direct selection during periods of secondary contact or, in turn, drove colour pattern differentiation in allopatry. Rather, we suggest that sexual isolation evolved as by-product of allopatric divergence. PMID:23405907

Melanosome evolution indicates a key physiological shift within feathered dinosaurs.

PubMed

Li, Quanguo; Clarke, Julia A; Gao, Ke-Qin; Zhou, Chang-Fu; Meng, Qingjin; Li, Daliang; D'Alba, Liliana; Shawkey, Matthew D

2014-03-20

Inference of colour patterning in extinct dinosaurs has been based on the relationship between the morphology of melanin-containing organelles (melanosomes) and colour in extant bird feathers. When this relationship evolved relative to the origin of feathers and other novel integumentary structures, such as hair and filamentous body covering in extinct archosaurs, has not been evaluated. Here we sample melanosomes from the integument of 181 extant amniote taxa and 13 lizard, turtle, dinosaur and pterosaur fossils from the Upper-Jurassic and Lower-Cretaceous of China. We find that in the lineage leading to birds, the observed increase in the diversity of melanosome morphologies appears abruptly, near the origin of pinnate feathers in maniraptoran dinosaurs. Similarly, mammals show an increased diversity of melanosome form compared to all ectothermic amniotes. In these two clades, mammals and maniraptoran dinosaurs including birds, melanosome form and colour are linked and colour reconstruction may be possible. By contrast, melanosomes in lizard, turtle and crocodilian skin, as well as the archosaurian filamentous body coverings (dinosaur 'protofeathers' and pterosaur 'pycnofibres'), show a limited diversity of form that is uncorrelated with colour in extant taxa. These patterns may be explained by convergent changes in the key melanocortin system of mammals and birds, which is known to affect pleiotropically both melanin-based colouration and energetic processes such as metabolic rate in vertebrates, and may therefore support a significant physiological shift in maniraptoran dinosaurs.

Dissecting the mechanism of Solanum lycopersicum and Solanum chilense flower colour formation.

PubMed

Gao, M; Qu, H; Gao, L; Chen, L; Sebastian, R S J; Zhao, L

2015-01-01

Flowers are the defining feature of angiosperms, and function as indispensable organs for sexual reproduction. Flower colour typically plays an important role in attracting pollinators, and can show considerable variation, even between closely related species. For example, domesticated tomato (S. lycopersicum) has orange/yellow flowers, while the wild relative S. chilense (accession LA2405) has bright yellow flowers. In this study, the mechanism of flower colour formation in these two species was compared by evaluating the accumulation of carotenoids, assessing the expression genes related to carotenoid biosynthetic pathways and observing chromoplast ultrastructure. In S. chilense petals, genes associated with the lutein branch of the carotenoid biosynthetic pathway, phytoene desaturase (PDS), ζ-carotene desaturase (ZDS), lycopene β-cyclase (LCY-B), β-ring hydroxylase (CRTR-B) and ε-ring hydroxylase (CRTR-E), were highly expressed, and this was correlated with high levels of lutein accumulation. In contrast, PDS, ZDS and CYC-B from the neoxanthin biosynthetic branch were highly expressed in S. lycopersicum anthers, leading to increased β-carotene accumulation and hence an orange/yellow colour. Changes in the size, amount and electron density of plastoglobules in chromoplasts provided further evidence of carotenoid accumulation and flower colour formation. Taken together, these results reveal the biochemical basis of differences in carotenoid pigment accumulation and colour between petals and anthers in tomato. © 2014 German Botanical Society and The Royal Botanical Society of the Netherlands.

Carotenoid accumulation in orange-pigmented Capsicum annuum fruit, regulated at multiple levels

PubMed Central

Rodriguez-Uribe, Laura; Guzman, Ivette; Rajapakse, Wathsala; Richins, Richard D.; O’Connell, Mary A.

2012-01-01

The pericarp of Capsicum fruit is a rich dietary source of carotenoids. Accumulation of these compounds may be controlled, in part, by gene transcription of biosynthetic enzymes. The carotenoid composition in a number of orange-coloured C. annuum cultivars was determined using HPLC and compared with transcript abundances for four carotenogenic enzymes, Psy, LcyB, CrtZ-2, and Ccs determined by qRT-PCR. There were unique carotenoid profiles as well as distinct patterns of transcription of carotenogenic enzymes within the seven orange-coloured cultivars. In one cultivar, ‘Fogo’, carrying the mutant ccs-3 allele, transcripts were detected for this gene, but no CCS protein accumulated. The premature stop termination in ccs-3 prevented expression of the biosynthetic activity to synthesize the capsanthin and capsorubin forms of carotenoids. In two other orange-coloured cultivars, ‘Orange Grande’ and ‘Oriole’, both with wild-type versions of all four carotenogenic enzymes, no transcripts for Ccs were detected and no red pigments accumulated. Finally, in a third case, the orange-coloured cultivar, Canary, transcripts for all four of the wild-type carotenogenic enzymes were readily detected yet no CCS protein appeared to accumulate and no red carotenoids were synthesized. In the past, mutations in Psy and Ccs have been identified as the loci controlling colour in the fruit. Now there is evidence that a non-structural gene may control colour development in Capsicum. PMID:21948863

Carotenoid accumulation in orange-pigmented Capsicum annuum fruit, regulated at multiple levels.

PubMed

Rodriguez-Uribe, Laura; Guzman, Ivette; Rajapakse, Wathsala; Richins, Richard D; O'Connell, Mary A

2012-01-01

The pericarp of Capsicum fruit is a rich dietary source of carotenoids. Accumulation of these compounds may be controlled, in part, by gene transcription of biosynthetic enzymes. The carotenoid composition in a number of orange-coloured C. annuum cultivars was determined using HPLC and compared with transcript abundances for four carotenogenic enzymes, Psy, LcyB, CrtZ-2, and Ccs determined by qRT-PCR. There were unique carotenoid profiles as well as distinct patterns of transcription of carotenogenic enzymes within the seven orange-coloured cultivars. In one cultivar, 'Fogo', carrying the mutant ccs-3 allele, transcripts were detected for this gene, but no CCS protein accumulated. The premature stop termination in ccs-3 prevented expression of the biosynthetic activity to synthesize the capsanthin and capsorubin forms of carotenoids. In two other orange-coloured cultivars, 'Orange Grande' and 'Oriole', both with wild-type versions of all four carotenogenic enzymes, no transcripts for Ccs were detected and no red pigments accumulated. Finally, in a third case, the orange-coloured cultivar, Canary, transcripts for all four of the wild-type carotenogenic enzymes were readily detected yet no CCS protein appeared to accumulate and no red carotenoids were synthesized. In the past, mutations in Psy and Ccs have been identified as the loci controlling colour in the fruit. Now there is evidence that a non-structural gene may control colour development in Capsicum.

Optimized two- and three-colour laser pulses for the intense terahertz wave generation

NASA Astrophysics Data System (ADS)

Zhang, Lei; Wang, Guo-Li; Zhou, Xiao-Xin

2016-11-01

Based on the photocurrent model, we perform a theoretical study on the optimization of terahertz (THz) wave emission from argon gas irradiated by the two- and three-colour laser fields. To obtain stronger THz radiation for the given conditions, a genetic algorithm method is applied to search for the optimum laser parameters. For the two-colour field, our optimizations reveal two types of optimal scheme, and each one dominates the THz generation in different regions of intensity ratio for a given total laser intensity. One scheme is the combination of a fundamental laser pulse and its second harmonic, while the other is the fundamental pulse with its fourth harmonic. For each scheme, the optimal intensity ratio and phase delay are obtained. For the three-colour case, our optimization shows that the excellent waveform for the strongest THz radiation is composed of a fundamental laser pulse, and its second, third harmonics, with appropriate intensity ratio and carrier-envelope phase. Such a 3-colour field can generate strong THz radiation comparable with a 10-colour sawtooth wave [Martínez et al., Phys. Rev. Lett. 114, 183901 (2015)]. The physical mechanisms for the enhancement of THz wave emission in gases are also discussed in detail. Our results give helpful guidance for intense THz generation with tabletop femtosecond laser device in experiment.

Deposition of carotenoids in egg yolk by short-term supplement of coloured carrot (Daucus carota) varieties as forage material for egg-laying hens.

PubMed

Hammershøj, Marianne; Kidmose, Ulla; Steenfeldt, Sanna

2010-05-01

Supplying egg-laying hens with different forage materials may influence egg production and quality. The aim of this study was to examine the short-term effects of standard feed plus 70 g day(-1) per hen of three coloured carrot varieties (orange, yellow and purple) as forage material in comparison with a standard feed control on egg production, egg yolk colour and deposition of carotenoids in the yolk. Carrot supplementation reduced feed intakes significantly, but not on a dry matter basis. Orange carrot treatment significantly reduced egg mass production, whereas yellow and purple carrot treatments did not differ from the control. Egg and yolk weights of all carrot-supplemented treatments were significantly lower than those of the control, but yolk percentages were similar. Yolk redness increased significantly in the order control < yellow < orange < purple. A similar trend was seen for yolk yellowness, but yellow and orange carrots reached the same level. Yolk colour and carotenoid contents correlated positively and significantly. In particular, purple carrot treatment increased the yolk content of lutein (>1.5-fold) and beta-carotene (>100-fold) compared with the control. Supplementing the feed of egg-laying hens with coloured carrots efficiently increased yolk colour parameters and carotenoid contents, which gives opportunities for improved nutritional value of eggs from forage material-supplemented hens.

Impaired distractor inhibition on a selective attention task in unmedicated, depressed subjects.

PubMed

MacQueen, G M; Tipper, S P; Young, L T; Joffe, R T; Levitt, A J

2000-05-01

Impaired distractor inhibition may contribute to the selective attention deficits observed in depressed patients, but studies to date have not tested the distractor inhibition theory against the possibility that processes such as transient memory review processes may account for the observed deficits. A negative priming paradigm can dissociate inhibition from such a potentially confounding process called object review. The negative priming task also isolates features of the distractor such as colour and location for independent examination. A computerized negative priming task was used in which colour, identification and location features of a stimulus and distractor were systematically manipulated across successive prime and probe trials. Thirty-two unmedicated subjects with DSM-IV diagnoses of non-psychotic unipolar depression were compared with 32 age, sex and IQ matched controls. Depressed subjects had reduced levels of negative priming for conditions where the colour feature of the stimulus was repeated across prime and probe trials but not when identity or location was the repeated feature. When both the colour and location feature were the repeated feature across trials, facilitation in response was apparent. The pattern of results supports studies that found reduced distractor inhibition in depressed subjects, and suggests that object review is intact in these subjects. Greater impairment in negative priming for colour versus location suggests that subjects may have greater impairment in the visual stream associated with processing colour features.

The colour preference control based on two-colour combinations

NASA Astrophysics Data System (ADS)

Hong, Ji Young; Kwak, Youngshin; Park, Du-Sik; Kim, Chang Yeong

2008-02-01

This paper proposes a framework of colour preference control to satisfy the consumer's colour related emotion. A colour harmony algorithm based on two-colour combinations is developed for displaying the images with several complementary colour pairs as the relationship of two-colour combination. The colours of pixels belonging to complementary colour areas in HSV colour space are shifted toward the target hue colours and there is no colour change for the other pixels. According to the developed technique, dynamic emotions by the proposed hue conversion can be improved and the controlled output image shows improved colour emotions in the preference of the human viewer. The psychophysical experiments are conducted to investigate the optimal model parameters to produce the most pleasant image to the users in the respect of colour emotions.

Limiting fragmentation from scale-invariant merging of fast partons

NASA Astrophysics Data System (ADS)

Bialas, A.; Bzdak, A.; Peschanski, R.

2008-07-01

Exploiting the idea that the fast partons of an energetic projectile can be treated as sources of colour radiation interpreted as wee partons, it is shown that the recently observed property of extended limiting fragmentation implies a scaling law for the rapidity distribution of fast partons. This leads to a picture of a self-similar process where, for fixed total rapidity Y, the sources merge with probability varying as 1 / y.

Methionine supplementation influences melanin-based plumage colouration in Eurasian kestrel, Falco tinnunculus, nestlings.

PubMed

Parejo, Deseada; Silva, Nadia

2009-11-01

The extent to which the expression of melanin-based plumage colouration in birds is genetically or environmentally determined is controversial. Here, we performed a between-nest design supplementation with either the sulphur amino acid dl-methionine or with water to investigate the importance of the non-genetic component of melanin-based plumage colouration in the Eurasian kestrel, Falco tinnunculus. Methionine affects growth and immunity, thus we aimed to modify nestling growth and immunity before feather development. Then, we measured the effect of the experiment on colouration of two melanin-based plumage patches of nestling kestrels. We found that methionine slowed down nestling growth through treatment administration and that nestlings compensated by speeding up their growth later. We did not find any effects of methionine on nestling immunity (i.e. lymphocyte counts, natural antibody levels or complement-mediated immunity). Effects on growth seemed to be mirrored by changes in nestling colouration in the two sexes: methionine-nestlings showed less intense brown plumage on their backs compared with control nestlings. These results provide support for a non-genetic determination of a melanin-based plumage patch in the two sexes of nestling kestrels.

A BRDF study on the visual appearance properties of titanium in the heating process

NASA Astrophysics Data System (ADS)

Liu, Yanlei; Yu, Kun; Li, Longfei; Zhao, Yuejin; Liu, Zilong; Liu, Yufang

2018-04-01

Bidirectional reflectance distribution function (BRDF) offers complete description of the spectral and spatial characteristics of opaque materials, i.e. the visual appearance properties of materials. In this letter, the visual appearance properties of titanium in the heating process are investigated by BRDF. The reliability of our results is verified by comparing the experimental data of polytetrafluoroethylene with the reference data. The in-plane spectral BRDF in visible region of heated commercial pure Ti at different incident and reflected zenith angles are measured. The experimental result indicates that the change tendency of BRDF vs. wavelength is not influenced by incident and reflected zenith angle, which implying that the colours of Ti may be pigment colouration rather than the structural colouration. Scanning electron microscopy (SEM) and the X-ray diffraction (XRD) testing are performed, and no titanium oxides are detected. The testing results imply that the colours may be generated by intermediate products during heated process. The powder samples are prepared, and the same colours as that of flake samples indirectly prove the validity of our conclusion. In addition, the spectral BRDF of optically smooth samples are measured, the results verify the reliability of our conclusion.

Comparison of shade matching by visual observation and an intraoral dental colorimeter.

PubMed

Li, Q; Wang, Y N

2007-11-01

The purpose of this study was to compare the applicability of two shade-matching approaches: Vintage Halo shade guide (visual method) and Shofu ShadeEye NCC colorimeter (instrumental method). Twenty participants' maxillary left central incisors were evaluated. Corresponding metal ceramic crowns were fabricated with each shade-matching approach. The colour distributions (L*, a* and b*) of the middle third region of each tooth and corresponding metal ceramic crowns were spectrophotometrically assessed. The colour difference (DeltaE) and colour distributions (DeltaL*, Deltaa* and Deltab*) between the tooth and the corresponding crowns were calculated. We found that the colour differences of both groups fell within the clinical unacceptable range (DeltaE > 2.75). Regarding DeltaE and the three colour distributions, no significant difference was found, expect for a* (P < 0.01). The shade matching difficulty degree was analysed through the agreements of visual shade selection. Within easy matching cases, the instrumental method achieved better results (P = 0.041). In conclusion, it is suggested that the reliability of shade matching can be ensured by neither the colorimeter nor the visual approach. However, the colorimeter can achieve better results within easy matching cases.

3D maps of the local interstellar medium: the impact of Gaia

NASA Astrophysics Data System (ADS)

Capitanio, L.; Lallement, R.; Vergely, J. L.; Elyajouri, M.; Babusiaux, C.; Ruiz-Dern, L.; Monreal-Ibero, A.; Arenou, F.; Danielski, C.

2017-12-01

Gaia parallaxes combined with colour excess and absorption measurements from large stellar surveys will allow building increasingly precise three-dimensional maps of the interstellar matter (ISM). Reciprocally, detailed maps of the ISM will allow improving photometric calibrations of Gaia and measuring more precisely the amounts of reddening. In the future, the extraction of a diffuse interstellar band (DIB) from Gaia RVS (Radial Velocity Spectrometer) spectra will allow to build a tomography of the carrier of this DIB and compare it with dust and gas distributions. Here we show several results that illustrate current progress in local ISM mapping and a first example of the stellar-interstellar synergy linked to Gaia: a) how Gaia-DR1 parallaxes already modify the ISM maps obtained by means of a full-3D inversion of a compilation of colour excess data, b) how DIB measurements and corresponding Gaia parallaxes can complement colour excess data and improve the maps, c) new hierarchical methods combining distinct surveys, d) improved maps including APOGEE colour excess estimates deduced from the recent Gaia-based photometric calibrations of Ruiz-Dern et al (this issue), e) additional inclusion of LAMOST colour excess estimates (Wang et al, 2016).

Anxious mood narrows attention in feature space.

PubMed

Wegbreit, Ezra; Franconeri, Steven; Beeman, Mark

2015-01-01

Spatial attention can operate like a spotlight whose scope can vary depending on task demands. Emotional states contribute to the spatial extent of attentional selection, with the spotlight focused more narrowly during anxious moods and more broadly during happy moods. In addition to visual space, attention can also operate over features, and we show here that mood states may also influence attentional scope in feature space. After anxious or happy mood inductions, participants focused their attention to identify a central target while ignoring flanking items. Flankers were sometimes coloured differently than targets, so focusing attention on target colour should lead to relatively less interference. Compared to happy and neutral moods, when anxious, participants showed reduced interference when colour isolated targets from flankers, but showed more interference when flankers and targets were the same colour. This pattern reveals that the anxious mood caused these individuals to attend to the irrelevant feature in both cases, regardless of its benefit or detriment. In contrast, participants showed no effect of colour on interference when happy, suggesting that positive mood did not influence attention in feature space. These mood effects on feature-based attention provide a theoretical bridge between previous findings concerning spatial and conceptual attention.

Accuracy assessment of satellite Ocean colour products in coastal waters.

NASA Astrophysics Data System (ADS)

Tilstone, G.; Lotliker, A.; Groom, S.

2012-04-01

The use of Ocean Colour Remote Sensing to monitor phytoplankton blooms in coastal waters is hampered by the absorption and scattering from substances in the water that vary independently of phytoplankton. In this paper we compare different ocean colour algorithms available for SeaWiFS, MODIS and MERIS with in situ observations of Remote Sensing Reflectance, Chlorophyll-a (Chla), Total Suspended Material and Coloured Dissolved Organic Material in coastal waters of the Arabian Sea, Bay of Bengal, North Sea and Western English Channel, which have contrasting inherent optical properties. We demonstrate a clustering method on specific-Inherent Optical Properties (sIOP) that gives accurate water quality products from MERIS data (HYDROPT) and also test the recently developed ESA CoastColour MERIS products. We found that for coastal waters of the Bay of Bengal, OC5 gave the most accurate Chla, for the Arabian Sea GSM and OC3M Chla were more accurate and for the North Sea and Western English Channel, MERIS HYDROPT were more accurate than standard algorithms. The reasons for these differences will be discussed. A Chla time series from 2002-2011 will be presented to illustrate differences in algorithms between coastal regions and inter- and intra-annual variability in phytoplankton blooms

Analysis of Visual Interpretation of Satellite Data

NASA Astrophysics Data System (ADS)

Svatonova, H.

2016-06-01

Millions of people of all ages and expertise are using satellite and aerial data as an important input for their work in many different fields. Satellite data are also gradually finding a new place in education, especially in the fields of geography and in environmental issues. The article presents the results of an extensive research in the area of visual interpretation of image data carried out in the years 2013 - 2015 in the Czech Republic. The research was aimed at comparing the success rate of the interpretation of satellite data in relation to a) the substrates (to the selected colourfulness, the type of depicted landscape or special elements in the landscape) and b) to selected characteristics of users (expertise, gender, age). The results of the research showed that (1) false colour images have a slightly higher percentage of successful interpretation than natural colour images, (2) colourfulness of an element expected or rehearsed by the user (regardless of the real natural colour) increases the success rate of identifying the element (3) experts are faster in interpreting visual data than non-experts, with the same degree of accuracy of solving the task, and (4) men and women are equally successful in the interpretation of visual image data.

Synaesthesia and colour constancy.

PubMed

Erskine, Holly; Mattingley, Jason B; Arnold, Derek H

2013-04-01

Grapheme-colour synaesthesia is an atypical condition characterized by the perception of colours when reading achromatic text. We investigated the level of colour processing responsible for these experiences. To do so, we tapped a central characteristic of colour perception. In different lighting conditions the same wavelength of light can prompt the perception of different colours. This helps humans recognize distinctive coloured objects despite changes in illumination. We wanted to see if synaesthetic colours were generated at a neural locus that was susceptible to colour constancy analyses. We used colour matching and naming tasks to examine interactions between simulated coloured illuminants and synaesthetic colours. Neither synaesthetic colour matching or naming was impacted. This contrasted with non-synaesthetic control participants, who performed the colour-matching task with graphemes physically coloured to mimic synaesthesia. Our data suggest that synaesthetic colour signals are not generated at lower-levels of colour processing, but are introduced at higher levels of analysis and are therefore not impacted by the processes responsible for perceptual constancy. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

The dark side of sniffing: paint colour affects intoxication experiences among adolescent inhalant users.

PubMed

Takagi, Michael J; Yücel, Murat; Lubman, Dan I

2010-07-01

Inhalant abuse among adolescents is a significant health concern in many countries; however, limited research has explored whether the intoxication experience differs between commonly used inhalants. The aim of the present study was to examine how exposure to different types of paints (chrome vs. non-chrome) were experienced by adolescent users. Sixteen adolescent (aged 15-19 years) regular inhalant users completed a semistructured questionnaire enquiring about their inhalant use. Participants were divided into two groups based on paint colour preference [chrome paints (n = 10) and non-chrome paints (n = 6)] and were compared using appropriate statistical tests. Relative to non-chrome users, the chrome-using group were more likely to report deliberately inhaling to experience altered perceptions (such as visual and auditory hallucinations). In addition, a significantly greater proportion of chrome users reported that the perceptual alterations they experienced after sniffing paint differed between paint colours, with chrome colours being associated with more vivid hallucinations. While both chrome and non-chrome users reported a comparable level of pleasure from paint sniffing, chrome paint users were more likely to be motivated by the potential to hallucinate. Our findings suggest that the type of inhalant used is an important consideration that may have relevance to clinical treatment.

Effects of emotional and non-emotional cues on visual search in neglect patients: evidence for distinct sources of attentional guidance.

PubMed

Lucas, Nadia; Vuilleumier, Patrik

2008-04-01

In normal observers, visual search is facilitated for targets with salient attributes. We compared how two different types of cue (expression and colour) may influence search for face targets, in healthy subjects (n=27) and right brain-damaged patients with left spatial neglect (n=13). The target faces were defined by their identity (singleton among a crowd of neutral faces) but could either be neutral (like other faces), or have a different emotional expression (fearful or happy), or a different colour (red-tinted). Healthy subjects were the fastest for detecting the colour-cued targets, but also showed a significant facilitation for emotionally cued targets, relative to neutral faces differing from other distracter faces by identity only. Healthy subjects were also faster overall for target faces located on the left, as compared to the right side of the display. In contrast, neglect patients were slower to detect targets on the left (contralesional) relative to the right (ipsilesional) side. However, they showed the same pattern of cueing effects as healthy subjects on both sides of space; while their best performance was also found for faces cued by colour, they showed a significant advantage for faces cued by expression, relative to the neutral condition. These results indicate that despite impaired attention towards the left hemispace, neglect patients may still show an intact influence of both low-level colour cues and emotional expression cues on attention, suggesting that neural mechanisms responsible for these effects are partly separate from fronto-parietal brain systems controlling spatial attention during search.

The merger remnant NGC 3610 and its globular cluster system: a large-scale study

NASA Astrophysics Data System (ADS)

Bassino, Lilia P.; Caso, Juan P.

2017-04-01

We present a photometric study of the prototype merger remnant NGC 3610 and its globular cluster (GC) system, based on new Gemini/GMOS and Advanced Camera for Surveys/Hubble Space Telescope archival images. Thanks to the large field of view of our GMOS data, larger than previous studies, we are able to detect a 'classical' bimodal GC colour distribution, corresponding to metal-poor and metal-rich GCs, at intermediate radii and a small subsample of likely young clusters of intermediate colours, mainly located in the outskirts. The extent of the whole GC system is settled as about 40 kpc. The GC population is quite poor, about 500 ± 110 members that corresponds to a low total specific frequency SN ˜ 0.8. The effective radii of a cluster sample are determined, including those of two spectroscopically confirmed young and metal-rich clusters, that are in the limit between GC and UCD sizes and brightness. The large-scale galaxy surface-brightness profile can be decomposed as an inner embedded disc and an outer spheroid, determining for both larger extents than earlier research (10 and 30 kpc, respectively). We detect boxy isophotes, expected in merger remnants, and show a wealth of fine-structure in the surface-brightness distribution with unprecedented detail, coincident with the outer spheroid. The lack of symmetry in the galaxy colour map adds a new piece of evidence to the recent merger scenario of NGC 3610.

Frequential versus spatial colour textons for breast TMA classification.

PubMed

Fernández-Carrobles, M Milagro; Bueno, Gloria; Déniz, Oscar; Salido, Jesús; García-Rojo, Marcial; Gonzández-López, Lucía

2015-06-01

Advances in digital pathology are generating huge volumes of whole slide (WSI) and tissue microarray images (TMA) which are providing new insights into the causes of cancer. The challenge is to extract and process effectively all the information in order to characterize all the heterogeneous tissue-derived data. This study aims to identify an optimal set of features that best separates different classes in breast TMA. These classes are: stroma, adipose tissue, benign and benign anomalous structures and ductal and lobular carcinomas. To this end, we propose an exhaustive assessment on the utility of textons and colour for automatic classification of breast TMA. Frequential and spatial texton maps from eight different colour models were extracted and compared. Then, in a novel way, the TMA is characterized by the 1st and 2nd order Haralick statistical descriptors obtained from the texton maps with a total of 241 × 8 features for each original RGB image. Subsequently, a feature selection process is performed to remove redundant information and therefore to reduce the dimensionality of the feature vector. Three methods were evaluated: linear discriminant analysis, correlation and sequential forward search. Finally, an extended bank of classifiers composed of six techniques was compared, but only three of them could significantly improve accuracy rates: Fisher, Bagging Trees and AdaBoost. Our results reveal that the combination of different colour models applied to spatial texton maps provides the most efficient representation of the breast TMA. Specifically, we found that the best colour model combination is Hb, Luv and SCT for all classifiers and the classifier that performs best for all colour model combinations is the AdaBoost. On a database comprising 628 TMA images, classification yields an accuracy of 98.1% and a precision of 96.2% with a total of 316 features on spatial textons maps. Copyright © 2014 Elsevier Ltd. All rights reserved.

Special tinted contact lens on colour-defects.

PubMed

Mutilab, H A; Sharanjeet-Kaur; Keu, L K; Choo, P F

2012-01-01

The objective of this study was to determine the visual function of colour-deficient subjects when wearing special red tint contact lenses. A total of 17 subjects with congenital colour vision deficiency (14 deutans and 3 protans), voluntarily participated in this study. The average age for the subjects was 23.00 ± 4.06 years old. Visual functions tested were visual acuity (LogMAR), contrast sensitivity (FACT Chart) and stereopsis (TNO and Howard Dolman tests). Two types of special red tint lenses were used in this study; Type I (light red) and Type II (dark red). The protans and deutans showed no significant changes in visual acuity and contrast sensitivity when wearing either type of contact lens. Stereopsis testing using the Horward-Dolman test gave no significant changes but significant differences were seen using the TNO test. Stereopsis using the TNO test was significantly poorer with the red tinted contact lenses compared to without for both protons and deutans. Testing binocularly with Ishihara plates showed that 88% (n=15) of patients passed the test with Type I and Type II contact lenses. When D15 test was done, 3 patients (17.6%) were 'normal' when using the Type I contact lenses and 2 patients (11.8%) were 'normal' when using the Type II contact lenses. However, with FM100Hue test, most patients showed deutan responses. Total error scores (TES) were found to be higher with Type I and Type II contact lenses compared to without. The Type I and II special tinted contact lens used in this study did not cause a reduction of visual acuity and contrast sensitivity for the colour defects. Stereopsis was also not reduced with the Type I and Type II contact lenses for the colour defects except when tested with the TNO test. Colour vision defects became difficult to detect using the Ishihara plates but FM100Hue test did not show any improvement with the Type I and Type II contact lenses.

Large-scale correlations in gas traced by Mg II absorbers around low-mass galaxies

NASA Astrophysics Data System (ADS)

Kauffmann, Guinevere

2018-03-01

The physical origin of the large-scale conformity in the colours and specific star formation rates of isolated low-mass central galaxies and their neighbours on scales in excess of 1 Mpc is still under debate. One possible scenario is that gas is heated over large scales by feedback from active galactic nuclei (AGNs), leading to coherent modulation of cooling and star formation between well-separated galaxies. In this Letter, the metal line absorption catalogue of Zhu & Ménard is used to probe gas out to large projected radii around a sample of a million galaxies with stellar masses ˜1010M⊙ and photometric redshifts in the range 0.4 < z < 0.8 selected from Sloan Digital Sky Survey imaging data. This galaxy sample covers an effective volume of 2.2 Gpc3. A statistically significant excess of Mg II absorbers is present around the red-low-mass galaxies compared to their blue counterparts out to projected radii of 10 Mpc. In addition, the equivalent width distribution function of Mg II absorbers around low-mass galaxies is shown to be strongly affected by the presence of a nearby (Rp < 2 Mpc) radio-loud AGNs out to projected radii of 5 Mpc.

The colour-magnitude relation of globular clusters in Centaurus and Hydra. Constraints on star cluster self-enrichment with a link to massive Milky Way globular clusters

NASA Astrophysics Data System (ADS)

Fensch, J.; Mieske, S.; Müller-Seidlitz, J.; Hilker, M.

2014-07-01

Aims: We investigate the colour-magnitude relation of metal-poor globular clusters, the so-called blue tilt, in the Hydra and Centaurus galaxy clusters and constrain the primordial conditions for star cluster self-enrichment. Methods: We analyse U,I photometry for about 2500 globular clusters in the central regions of Hydra and Centaurus, based on VLT/FORS1 data. We measure the relation between mean colour and luminosity for the blue and red subpopulation of the globular cluster samples. We convert these relations into mass-metallicity space and compare the obtained GC mass-metallicity relation with predictions from the star cluster self-enrichment model by Bailin & Harris (2009, ApJ, 695, 1082). For this we include effects of dynamical and stellar evolution and a physically well motivated primordial mass-radius scaling. Results: We obtain a mass-metallicity scaling of Z ∝ M0.27 ± 0.05 for Centaurus GCs and Z ∝ M0.40 ± 0.06 for Hydra GCs, consistent with the range of observed relations in other environments. We find that the GC mass-metallicity relation already sets in at present-day masses of a few and is well established in the luminosity range of massive MW clusters like ω Centauri. The inclusion of a primordial mass-radius scaling of star clusters significantly improves the fit of the self-enrichment model to the data. The self-enrichment model accurately reproduces the observed relations for average primordial half-light radii rh ~ 1-1.5 pc, star formation efficiencies f⋆ ~ 0.3-0.4, and pre-enrichment levels of [Fe/H] - 1.7 dex. The slightly steeper blue tilt for Hydra can be explained either by a ~30% smaller average rh at fixed f⋆ ~ 0.3, or analogously by a ~20% smaller f⋆ at fixed rh ~ 1.5 pc. Within the self-enrichment scenario, the observed blue tilt implies a correlation between GC mass and width of the stellar metallicity distribution. We find that this implied correlation matches the trend of width with GC mass measured in Galactic GCs, including extreme cases like ω Centauri and M 54. Conclusions: First, we found that a primordial star cluster mass-radius relation provides a significant improvement to the self-enrichment model fits. Second we show that broadened metallicity distributions as found in some massive MW globular clusters may have arisen naturally from self-enrichment processes, without the need of a dwarf galaxy progenitor.

Egg production and quality under three housing systems in the tropics.

PubMed

Varguez-Montero, Grissly; Sarmiento-Franco, Luis; Santos-Ricalde, Ronald; Segura-Correa, Jose

2012-02-01

The aim of this study was to evaluate egg production and quality of Rhode Island Red (RIR) laying hens in an outdoor system in the subhumid tropic. Eighty RIR laying hens were measured in two periods and housed randomly under three treatments: outdoor (O), indoor (I) and in conventional cages (C). Egg weight (55.88, 53.76 and 57.16 g, for O, I and C, respectively), food intake/hen/day (138.94, 129.74 and 162.90 g, for O, I and C, respectively) and food efficiency (3.13, 3.22 and 3.96 for O, I and C, respectively) were significantly (P < 0.05) influenced by housing system; however, both egg production and final body weight were not different (P > 0.05). Yolk colour (10.76, 9.94 and 10.08 colour scale, for O, I and C, respectively), albumen weight (92.63, 92.28 and 90.08 g, for O, I and C, respectively) and yolk weight (15.19, 14.61, 15.48 g for O, I and C, respectively) were significantly (P < 0.05) influenced by housing system, but albumen height, Haugh units and egg shell weight remained similar (P > 0.05). Under the conditions of this study, outdoor egg production seems to be a sustainable system comparable to the commercial type based on wired cages.

Extrapolating from local ecological processes to genus-wide patterns in colour polymorphism in South African Protea.

PubMed

Carlson, Jane E; Holsinger, Kent E

2015-05-07

Polymorphic traits are central to many fundamental discoveries in evolution, yet why they are found in some species and not others remains poorly understood. We use the African genus Protea-within which more than 40% of species have co-occurring pink and white floral colour morphs-to ask whether convergent evolution and ecological similarity could explain the genus-wide pattern of polymorphism. First, we identified environmental correlates of pink morph frequency across 28 populations of four species. Second, we determined whether the same correlates could predict species-level polymorphism and monomorphism across 31 species. We found that pink morph frequency increased with elevation in Protea repens and three section Exsertae species, increased eastward in P. repens, and increased with seed predation intensity in section Exsertae. For cross-species comparisons, populations of monomorphic pink species occurred at higher elevations than populations of monomorphic white species, and 18 polymorphic species spanned broader elevational gradients than 13 monomorphic species. These results suggest that divergent selection along elevational clines has repeatedly favoured polymorphism, and that more uniform selection in altitudinally restricted species may promote colour monomorphism. Our findings are, to our knowledge, the first to link selection acting within species to the presence and absence of colour polymorphism at broader phylogenetic scales. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Short communication: investigating the effect of saffron (Crocus sativus L.) nano-sizing on its colour extraction efficiency: a preliminary study.

PubMed

Abootalebian, Mehrdad; Karbasi, Maryam; Sadeghi, Maliheh; Abdinian, Mahnaz; Polikarpov, Igor

2017-10-01

This study investigated the effect of saffron nano-sizing on its the colour extraction yield. The whole stigma was ball-milled at three different times (10, 20 and 100 h), immediately or with a 24 h delay was submitted to absorption test, and then the colour extraction efficiency was determined. When stigma was milled for 100 h, its particle size was reduced to less than 20 nm, as shown by SEM and TEM images, and its extraction efficiency was considerably increased by 19.8% as compared with the stigma blended for 10 min. However with a 24 h delay between the end of milling and absorption test, the yield of colour extraction significantly decreased. The recommended milling conditions resulting in extraction efficiency of 16.2% (in comparison with stigma blended for 10 min) were determined to be the milling for 10 h with initial tendering prior to milling operation.

Muscle fibre characteristics, enzyme activity and meat colour of wild boar (Sus scrofa s. L.) muscle with 2n=36 compared to those of phenotypically similar crossbreeds (2n=37 and 2n=38).

PubMed

Skewes, Oscar; Cádiz, Patricia; Merino, Victoria; Islas, Armando; Morales, Rodrigo

2014-10-01

The aim of the present study was to evaluate European wild boar (Sus scrofa s. L.) of chromosomal number 2n=36 in comparison with phenotypically similar crossbreeds (2n=37 and 2n=38) with respect to the muscle fibre characteristics and enzyme activity as well as meat colour in the longissimus dorsi (LD) and semimembranosus (SM) muscles. Differences in the proportion of IIA fibre in the LD muscle between karyotypes 2n=37 and 2n=38 were found. The 2n=36 group showed a lower muscle fibre cross-section area than the 2n=38 karyotype. The meat colour of the 2n=36 karyotype group was redder than 2n=37 and 2n=38. The muscle fibre cross-section area might explain the differences in colour of the meat of wild boar. Copyright © 2014 Elsevier Ltd. All rights reserved.

Colour centre recovery in yttria-stabilised zirconia: photo-induced versus thermal processes

NASA Astrophysics Data System (ADS)

Costantini, Jean-Marc; Touati, Nadia; Binet, Laurent; Lelong, Gérald; Guillaumet, Maxime; Beuneu, François

2018-05-01

The photo-annealing of colour centres in yttria-stabilised zirconia (YSZ) was studied by electron paramagnetic resonance spectroscopy upon UV-ray or laser light illumination, and compared to thermal annealing. Stable hole centres (HCs) were produced in as-grown YSZ single crystals by UV-ray irradiation at room temperature (RT). The HCs produced by 200-MeV Au ion irradiation, as well as the F+-type centres (? centres involving oxygen vacancies) were left unchanged upon UV illumination. In contrast, a significant photo-annealing of the latter point defects was achieved in 1.4-MeV electron-irradiated YSZ by 553-nm laser light irradiation at RT. Almost complete photo-bleaching was achieved by laser irradiation inside the absorption band of ? centres centred at a wavelength 550 nm. Thermal annealing of these colour centres was also followed by UV-visible absorption spectroscopy showing full bleaching at 523 K. Colour-centre evolutions by photo-induced and thermally activated processes are discussed on the basis of charge exchange processes between point defects.

Development of Fire Detection Algorithm at Its Early Stage Using Fire Colour and Shape Information

NASA Astrophysics Data System (ADS)

Suleiman Abdullahi, Zainab; Hamisu Dalhatu, Shehu; Hassan Abdullahi, Zakariyya

2018-04-01

Fire can be defined as a state in which substances combined chemically with oxygen from the air and give out heat, smoke and flame. Most of the conventional fire detection techniques such as smoke, fire and heat detectors respectively have a problem of travelling delay and also give a high false alarm. The algorithm begins by loading the selected video clip from the database developed to identify the present or absence of fire in a frame. In this approach, background subtraction was employed. If the result of subtraction is less than the set threshold, the difference is ignored and the next frame is taken. However, if the difference is equal to or greater than the set threshold then it subjected to colour and shape test. This is done by using combined RGB colour model and shape signature. The proposed technique was very effective in detecting fire compared to those technique using only motion or colour clues.

Effect of vacuum roasting on acrylamide formation and reduction in coffee beans.

PubMed

Anese, Monica; Nicoli, Maria Cristina; Verardo, Giancarlo; Munari, Marina; Mirolo, Giorgio; Bortolomeazzi, Renzo

2014-02-15

Coffea arabica beans were roasted in an oven at 200 °C for increasing lengths of time under vacuum (i.e. 0.15 kPa). The samples were then analysed for colour, weight loss, acrylamide concentration and sensory properties. Data were compared with those obtained from coffee roasted at atmospheric pressure (i.e. conventional roasting), as well as at atmospheric pressure for 10 min followed by vacuum treatment (0.15 kPa; i.e. conventional-vacuum roasting). To compare the different treatments, weight loss, colour and acrylamide changes were expressed as a function of the thermal effect received by the coffee beans during the different roasting processes. Vacuum-processed coffee with medium roast degree had approximately 50% less acrylamide than its conventionally roasted counterpart. It was inferred that the low pressure generated inside the oven during the vacuum process exerted a stripping effect preventing acrylamide from being accumulated. Vacuum-processed coffee showed similar colour and sensory properties to conventionally roasted coffee. Copyright © 2013 Elsevier Ltd. All rights reserved.

Comparison of performance of computer display monitors for radiological diagnosis; "diagnostic" high brightness monochrome LCD, 3MP vs "clinical review" colour LCD, 2MP.

PubMed

Sim, L; Manthey, K; Stuckey, S

2007-06-01

A study to compare performance of the following display monitors for application as PACS CR diagnostic workstations is described. 1. Diagnostic quality, 3 Mega Pixel, 21 inch monochrome LCD monitors--Planar C3i. 2. Clinical review quality, 2 Mega Pixel, 21 inch colour LCD monitors--Planar PX212. Two sets of seventy radiological studies were presented to four senior radiologists on two occasions, using different displays on each occasion. The clinical condition used for this investigation was to query for the presence of a solitary pulmonary nodule. Receiver Operating Characteristic (ROC) curves were constructed for diagnostic performance for each presentation. Areas under the ROC curves (AUC) for diagnosis using different monitors were compared and the following results obtained: Monochrome AUC = 0.813 +/- 0.02, Colour AUC = 0.801 +/- 0.021. These results indicate that there is no statistically significant difference in the performance of these monitor types at a 95% confidence level.

Drain blocking: an effective treatment for reducing dissolved organic carbon loss and water discolouration in a drained peatland.

PubMed

Wallage, Zoe E; Holden, Joseph; McDonald, Adrian T

2006-08-31

Peatlands are an important terrestrial carbon store. However, heightened levels of degradation in response to environmental change have resulted in an increased loss of dissolved organic carbon (DOC) and an associated rise in the level of discolouration in catchment waters. A significant threat to peatland sustainability has been the installation of artificial drainage ditches. However, recent restoration schemes have pursued drain blocking as a possible strategy for reducing degradation, fluvial carbon loss and water discolouration. This paper investigates the effect of open cut drainage and the impact of drain blocking on DOC and colour dynamics in blanket peat soil-water solutions. Three treatments (intact peat, drained peat and drain-blocked peat) were monitored in an upland blanket peat catchment in the UK. DOC and colour values were significantly higher on the drained slopes compared with those of the intact peat, which in turn had greater DOC and colour values than the drain-blocked slopes. Consequently, drain blocking is shown to be a highly successful technique in reducing both the DOC concentration and level of discolouration in soil waters, even to values lower than those observed for the intact site, which suggests a process of store exhaustion and flushing may operate. The colour per carbon unit (C/C) ratio was significantly higher at the drain-blocked site than either the intact or the drained treatments, while the E4/E6 ratio (fulvic acid/humic acid) was significantly lower at the blocked site compared to the two other treatments. The high C/C and low E4/E6 ratios indicate that drain blocking also modifies the composition of DOC, such that darker-coloured humic substances become more dominant compared to the intact site. This implies disturbance to DOC production and/or transportation processes operating within the peat.

Spatial harmonics and pattern specification in early Drosophila development. Part II. The four colour wheels model.

PubMed

Kauffman, S A; Goodwin, B C

1990-06-07

We review the evidence presented in Part I showing that transcripts and protein products of maternal, gap, pair-rule, and segment polarity genes exhibit increasingly complex, multipeaked longitudinal waveforms in the early Drosophila embryo. The central problem we address in Part II is the use the embryo makes of these wave forms to specify longitudinal pattern. Based on the fact that mutants of many of these genes generate deletions and mirror symmetrical duplications of pattern elements on length scales ranging from about half the egg to within segments, we propose that position is specified by measuring a "phase angle" by use of the ratios of two or more variables. Pictorially, such a phase angle can be thought of as a colour on a colour wheel. Any such model contains a phaseless singularity where all or many phases, or colours, come together. We suppose as well that positional values sufficiently close to the singularity are meaningless, hence a "dead zone". Duplications and deletions are accounted for by deformation of the cycle of morphogen values occurring along the antero-posterior axis. If the cycle of values surrounds the singularity and lies outside the dead zone, pattern is normal. If the curve transects the dead zone, pattern elements are deleted. If the curve lies entirely on one side of the singularity, pattern elements are deleted and others are duplicated with mirror symmetry. The existence of different wavelength transcript patterns in maternal, gap, pair-rule, and segment polarity genes and the roles of those same genes in generating deletions and mirror symmetrical duplications on a variety of length scales lead us to propose that position is measured simultaneously on at least four colour wheels, which cycle different numbers of times along the anterior-posterior axis. These yield progressively finer grained positional information. Normal pattern specification requires a unique angle, outside of the dead zone, from each of the four wheels. Deformations of the cycle of gene product concentrations yield the deletions and mirror symmetric duplications observed in the mutants discussed. The alternative familiar hypothesis that longitudinal position is specified in an "on" "off" combinatorial code does not readily account for the duplication deletion phenomena.

Making comparative performance information more comprehensible: an experimental evaluation of the impact of formats on consumer understanding

PubMed Central

Damman, Olga C; De Jong, Anco; Hibbard, Judith H; Timmermans, Danielle R M

2016-01-01

Study objectives We aimed to investigate how different presentation formats influence comprehension and use of comparative performance information (CPI) among consumers. Methods An experimental between-subjects and within-subjects design with manipulations of CPI presentation formats. We enrolled both consumers with lower socioeconomic status (SES)/cognitive skills and consumers with higher SES/cognitive skills, recruited through an online access panel. Respondents received fictitious CPI and completed questions about interpretation and information use. Between subjects, we tested (1) displaying an overall performance score (yes/no); (2) displaying a small number of quality indicators (5 vs 9); and (3) displaying different types of evaluative symbols (star ratings, coloured dots and word icons vs numbers and bar graphs). Within subjects, we tested the effect of a reduced number of healthcare providers (5 vs 20). Data were analysed using descriptive analysis, analyses of variance and paired-sampled t tests. Results A total of 902 (43%) respondents participated. Displaying an overall performance score and the use of coloured dots and word icons particularly enhanced consumer understanding. Importantly, respondents provided with coloured dots most often correctly selected the top three healthcare providers (84.3%), compared with word icons (76.6% correct), star ratings (70.6% correct), numbers (62.0%) and bars (54.2%) when viewing performance scores of 20 providers. Furthermore, a reduced number of healthcare providers appeared to support consumers, for example, when provided with 20 providers, 69.5% correctly selected the top three, compared with 80.2% with five providers. Discussion Particular presentation formats enhanced consumer understanding of CPI, most importantly the use of overall performance scores, word icons and coloured dots, and a reduced number of providers displayed. Public report efforts should use these formats to maximise impact on consumers. PMID:26543066

Photochemistry of Artists' Dyes and Pigments: Towards Better Understanding and Prevention of Colour Change in Works of Art.

PubMed

Miliani, Costanza; Monico, Letizia; Melo, Maria J; Fantacci, Simona; Angelin, Eva M; Romani, Aldo; Janssens, Koen

2018-06-18

The absorption of light gives a pigment its colour and its reason for being, but it also creates excited states, that is, new molecules with an energy excess that can be dissipated through degradation pathways. Photodegradation processes provoke long-term, cumulative and irreversible colour changes (fading, darkening, blanching) of which the prediction and prevention are challenging tasks. Of all the environmental risks that affect heritage materials, light exposure is the only one that cannot be controlled without any impact on the optimal display of the exhibit. Light-induced alterations are not only associated with the pigment itself but also with its interactions with support/binder and, in turn, are further complicated by the nature of the environmental conditions. In this Minireview we investigate how chemistry, encompassing multi-scale analytical investigations of works of art, computational modelling and physical and chemical studies contributes to improve our prediction of artwork appearance before degradation and to establish effective preventive conservation strategies. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Does Colour Preference Have a Role in Colour Term Acquisition?

ERIC Educational Resources Information Center

Pitchford, Nicola J.; Davis, Emma E.; Scerif, Gaia

2009-01-01

A developmental association exists between colour preference and emerging colour term acquisition in young children. Colour preference might influence colour term acquisition by directing attention towards or away from a particular colour, making it more or less memorable. To investigate the role that colour preference may have in the acquisition…

The role of colour in implicit and explicit memory performance.

PubMed

Vernon, David; Lloyd-Jones, Toby J

2003-07-01

We present two experiments that examine the effects of colour transformation between study and test (from black and white to colour and vice versa, of from incorrectly coloured to correctly coloured and vice versa) on implicit and explicit measures of memory for diagnostically coloured natural objects (e.g., yellow banana). For naming and coloured-object decision (i.e., deciding whether an object is correctly coloured), there were shorter response times to correctly coloured-objects than to black-and-white and incorrectly coloured-objects. Repetition priming was equivalent for the different stimulus types. Colour transformation did not influence priming of picture naming, but for coloured-object decision priming was evident only for objects remaining the same from study to test. This was the case for both naming and coloured-object decision as study tasks. When participants were asked to consciously recognize objects that they had named or made coloured-object decisions to previously, whilst ignoring their colour, colour transformation reduced recognition efficiency. We discuss these results in terms of the flexibility of object representations that mediate priming and recognition.

A handheld optical device for skin profile measurement

NASA Astrophysics Data System (ADS)

Sun, Jiuai; Liu, Xiaojin

2018-04-01

This paper describes a portable optical scanning device designed for skin surface measurement on both colour and 3D geometry through a relative easy and cost effective multiple light source photometric stereo method. The validation of colour recovered had been verified through its application on skin lesion segmentation in our early work. This paper focuses on the reconstructed topographic data which are subject to further evaluation and advancement. The evaluation work takes the skin in vitro as an application scenario and compares the experimental result to that obtained by using a commercial product. The experiments show that this handheld device can measure the skin profile significantly closer to that of the ground truth and have the additional function of skin colour recovery.

Infrared observations of metal-deficient stars

NASA Astrophysics Data System (ADS)

Arribas, S.; Martinez Roger, C.

1987-09-01

Infrared magnitudes in the J, H, K and L bands for 64 metal-deficient stars spanning a wide range in effective temperature, luminosity and metal content are presented. An accuracy of 0.02 magnitude is obtained for the JHK bands and 0.03 for the L filter. Infrared-infrared and optical-infrared colour-colour diagrams are discussed and compared with the mean intrinsic tracks for Population I stars. It is concluded that infrared colours are not notably dependent on metallicity, with some exceptions for the reddest giants, which can be also interpreted by residual effects in the transformation equations between different systems. The authors also discuss briefly the near infrared photometric system of the Observatorio del Teide, from the Instituto de Astrofisica de Canarias.