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Sample records for total colour difference

  1. Influence of different maceration time and temperatures on total phenols, colour and sensory properties of Cabernet Sauvignon wines.

    PubMed

    Şener, Hasan; Yildirim, Hatice Kalkan

    2013-12-01

    Maceration and fermentation time and temperatures are important factors affecting wine quality. In this study different maceration times (3 and 6 days) and temperatures (15  and 25 ) during production of red wine (Vitis vinifera L. Cabernet Sauvignon) were investigated. In all wines standard wine chemical parameters and some specific parameters as total phenols, tartaric esters, total flavonols and colour parameters (CD, CI, T, dA%, %Y, %R, %B, CIELAB values) were determined. Sensory evaluation was performed by descriptive sensory analysis. The results demonstrated not only the importance of skin contact time and temperature during maceration but also the effects of transition temperatures (different maceration and fermentation temperatures) on wine quality as a whole. The results of sensory descriptive analyses revealed that the temperature significantly affected the aroma and flavour attributes of wines. The highest scores for 'cassis', 'clove', 'fresh fruity' and 'rose' characters were obtained in wines produced at low temperature (15 ) of maceration (6 days) and fermentation.

  2. Quantifying Plant Colour and Colour Difference as Perceived by Humans Using Digital Images

    PubMed Central

    Kendal, Dave; Hauser, Cindy E.; Garrard, Georgia E.; Jellinek, Sacha; Giljohann, Katherine M.; Moore, Joslin L.

    2013-01-01

    Human perception of plant leaf and flower colour can influence species management. Colour and colour contrast may influence the detectability of invasive or rare species during surveys. Quantitative, repeatable measures of plant colour are required for comparison across studies and generalisation across species. We present a standard method for measuring plant leaf and flower colour traits using images taken with digital cameras. We demonstrate the method by quantifying the colour of and colour difference between the flowers of eleven grassland species near Falls Creek, Australia, as part of an invasive species detection experiment. The reliability of the method was tested by measuring the leaf colour of five residential garden shrub species in Ballarat, Australia using five different types of digital camera. Flowers and leaves had overlapping but distinct colour distributions. Calculated colour differences corresponded well with qualitative comparisons. Estimates of proportional cover of yellow flowers identified using colour measurements correlated well with estimates obtained by measuring and counting individual flowers. Digital SLR and mirrorless cameras were superior to phone cameras and point-and-shoot cameras for producing reliable measurements, particularly under variable lighting conditions. The analysis of digital images taken with digital cameras is a practicable method for quantifying plant flower and leaf colour in the field or lab. Quantitative, repeatable measurements allow for comparisons between species and generalisations across species and studies. This allows plant colour to be related to human perception and preferences and, ultimately, species management. PMID:23977275

  3. Quantifying plant colour and colour difference as perceived by humans using digital images.

    PubMed

    Kendal, Dave; Hauser, Cindy E; Garrard, Georgia E; Jellinek, Sacha; Giljohann, Katherine M; Moore, Joslin L

    2013-01-01

    Human perception of plant leaf and flower colour can influence species management. Colour and colour contrast may influence the detectability of invasive or rare species during surveys. Quantitative, repeatable measures of plant colour are required for comparison across studies and generalisation across species. We present a standard method for measuring plant leaf and flower colour traits using images taken with digital cameras. We demonstrate the method by quantifying the colour of and colour difference between the flowers of eleven grassland species near Falls Creek, Australia, as part of an invasive species detection experiment. The reliability of the method was tested by measuring the leaf colour of five residential garden shrub species in Ballarat, Australia using five different types of digital camera. Flowers and leaves had overlapping but distinct colour distributions. Calculated colour differences corresponded well with qualitative comparisons. Estimates of proportional cover of yellow flowers identified using colour measurements correlated well with estimates obtained by measuring and counting individual flowers. Digital SLR and mirrorless cameras were superior to phone cameras and point-and-shoot cameras for producing reliable measurements, particularly under variable lighting conditions. The analysis of digital images taken with digital cameras is a practicable method for quantifying plant flower and leaf colour in the field or lab. Quantitative, repeatable measurements allow for comparisons between species and generalisations across species and studies. This allows plant colour to be related to human perception and preferences and, ultimately, species management.

  4. Minimum Perceptible Differences in the Colour Reproduction of Photographic Prints.

    NASA Astrophysics Data System (ADS)

    Wood, Carol Ann

    Available from UMI in association with The British Library. Electronic simulations of the Macbeth Color Checker Chart were prepared such that each of the eighteen colour patches could be varied independently from the rest of the chart. The output was in the form of photographic colour prints which comprised a ring-around set of 168 prints for each of the colour patches, where each print was a colour perturbation from a standard print. Twelve observers, with normal colour vision, judged the prints in each set to be perceptibly different or not perceptibly different from the standard print, for each patch. The experimental results, in the form of hue-orientated and non hue-orientated ellipses, were compared with MacAdam type ellipses, CIELAB unit ellipses and ellipses derived from the CMC(1:c) colour difference formula: the comparisons were made in the 1976 CIELAB colour space. Colour reproduction indices were calculated for the end points of the semi-major and semi-minor axes of the CMC ellipses, for each of the eighteen colour patches. The coefficient of variation was very small for the combined hue index, the combined chroma index and the overall combined index, indicating that the mean values for these indices could be assigned to any of the ellipses as a measure of the minimum perceptible difference in terms of colour appearance.

  5. Testing the AUDI2000 colour-difference formula for solid colours using some visual datasets with usefulness to automotive industry

    NASA Astrophysics Data System (ADS)

    Martínez-García, Juan; Melgosa, Manuel; Gómez-Robledo, Luis; Li, Changjun; Huang, Min; Liu, Haoxue; Cui, Guihua; Luo, M. Ronnier; Dauser, Thomas

    2013-11-01

    Colour-difference formulas are tools employed in colour industries for objective pass/fail decisions of manufactured products. These objective decisions are based on instrumental colour measurements which must reliably predict the subjective colour-difference evaluations performed by observers' panels. In a previous paper we have tested the performance of different colour-difference formulas using the datasets employed at the development of the last CIErecommended colour-difference formula CIEDE2000, and we found that the AUDI2000 colour-difference formula for solid (homogeneous) colours performed reasonably well, despite the colour pairs in these datasets were not similar to those typically employed in the automotive industry (CIE Publication x038:2013, 465-469). Here we have tested again AUDI2000 together with 11 advanced colour-difference formulas (CIELUV, CIELAB, CMC, BFD, CIE94, CIEDE2000, CAM02-UCS, CAM02-SCD, DIN99d, DIN99b, OSA-GP-Euclidean) for three visual datasets we may consider particularly useful to the automotive industry because of different reasons: 1) 828 metallic colour pairs used to develop the highly reliable RIT-DuPont dataset (Color Res. Appl. 35, 274-283, 2010); 2) printed samples conforming 893 colour pairs with threshold colour differences (J. Opt. Soc. Am. A 29, 883-891, 2012); 3) 150 colour pairs in a tolerance dataset proposed by AUDI. To measure the relative merits of the different tested colour-difference formulas, we employed the STRESS index (J. Opt. Soc. Am. A 24, 1823-1829, 2007), assuming a 95% confidence level. For datasets 1) and 2), AUDI2000 was in the group of the best colour-difference formulas with no significant differences with respect to CIE94, CIEDE2000, CAM02-UCS, DIN99b and DIN99d formulas. For dataset 3) AUDI2000 provided the best results, being statistically significantly better than all other tested colour-difference formulas.

  6. Physical features, phenolic compounds, betalains and total antioxidant capacity of coloured quinoa seeds (Chenopodium quinoa Willd.) from Peruvian Altiplano.

    PubMed

    Abderrahim, Fatima; Huanatico, Elizabeth; Segura, Roger; Arribas, Silvia; Gonzalez, M Carmen; Condezo-Hoyos, Luis

    2015-09-15

    Physical features, bioactive compounds and total antioxidant capacity (TAC) of coloured quinoa varieties (Chenopodium quinoa Willd.) from Peruvian Altiplano were studied. Quinoa seeds did not show a pure red colour, but a mixture which corresponded to different fractal colour values (51.0-71.8), and they varied from small to large size. Regarding bioactive compounds, total phenolic (1.23-3.24mg gallic acid equivalents/g) and flavonol contents (0.47-2.55mg quercetin equivalents/g) were highly correlated (r=0.910). Betalains content (0.15-6.10mg/100g) was correlated with L colour parameter (r=-0.569), total phenolics (r=0.703) and flavonols content (r=0.718). Ratio of betaxanthins to betacyanins (0.0-1.41) was negatively correlated with L value (r=-0.744). Whereas, high TAC values (119.8-335.9mmol Trolox equivalents/kg) were negatively correlated with L value (r=-0.779), but positively with betalains (r=0.730), as well as with free (r=0.639), bound (r=0.558) and total phenolic compounds (r=0.676). Unexploited coloured quinoa seeds are proposed as a valuable natural source of phenolics and betalains with high antioxidant capacity.

  7. Physical features, phenolic compounds, betalains and total antioxidant capacity of coloured quinoa seeds (Chenopodium quinoa Willd.) from Peruvian Altiplano.

    PubMed

    Abderrahim, Fatima; Huanatico, Elizabeth; Segura, Roger; Arribas, Silvia; Gonzalez, M Carmen; Condezo-Hoyos, Luis

    2015-09-15

    Physical features, bioactive compounds and total antioxidant capacity (TAC) of coloured quinoa varieties (Chenopodium quinoa Willd.) from Peruvian Altiplano were studied. Quinoa seeds did not show a pure red colour, but a mixture which corresponded to different fractal colour values (51.0-71.8), and they varied from small to large size. Regarding bioactive compounds, total phenolic (1.23-3.24mg gallic acid equivalents/g) and flavonol contents (0.47-2.55mg quercetin equivalents/g) were highly correlated (r=0.910). Betalains content (0.15-6.10mg/100g) was correlated with L colour parameter (r=-0.569), total phenolics (r=0.703) and flavonols content (r=0.718). Ratio of betaxanthins to betacyanins (0.0-1.41) was negatively correlated with L value (r=-0.744). Whereas, high TAC values (119.8-335.9mmol Trolox equivalents/kg) were negatively correlated with L value (r=-0.779), but positively with betalains (r=0.730), as well as with free (r=0.639), bound (r=0.558) and total phenolic compounds (r=0.676). Unexploited coloured quinoa seeds are proposed as a valuable natural source of phenolics and betalains with high antioxidant capacity. PMID:25863614

  8. Marked colour divergence in the gliding membranes of a tropical lizard mirrors population differences in the colour of falling leaves

    PubMed Central

    Klomp, D. A.; Stuart-Fox, D.; Das, I.; Ord, T. J.

    2014-01-01

    Populations of the Bornean gliding lizard, Draco cornutus, differ markedly in the colour of their gliding membranes. They also differ in local vegetation type (mangrove forest versus lowland rainforest) and consequently, the colour of falling leaves (red and brown/black in mangrove versus green, brown and black in rainforest). We show that the gliding membranes of these lizards closely match the colours of freshly fallen leaves in the local habitat as they appear to the visual system of birds (their probable predators). Furthermore, gliding membranes more closely resembled colours of local fallen leaves than standing foliage or fallen leaves in the other population's habitat. This suggests that the two populations have diverged in gliding membrane coloration to match the colours of their local falling leaves, and that mimicking falling leaves is an adaptation that functions to reduce predation by birds. PMID:25540157

  9. Marked colour divergence in the gliding membranes of a tropical lizard mirrors population differences in the colour of falling leaves.

    PubMed

    Klomp, D A; Stuart-Fox, D; Das, I; Ord, T J

    2014-12-01

    Populations of the Bornean gliding lizard, Draco cornutus, differ markedly in the colour of their gliding membranes. They also differ in local vegetation type (mangrove forest versus lowland rainforest) and consequently, the colour of falling leaves (red and brown/black in mangrove versus green, brown and black in rainforest). We show that the gliding membranes of these lizards closely match the colours of freshly fallen leaves in the local habitat as they appear to the visual system of birds (their probable predators). Furthermore, gliding membranes more closely resembled colours of local fallen leaves than standing foliage or fallen leaves in the other population's habitat. This suggests that the two populations have diverged in gliding membrane coloration to match the colours of their local falling leaves, and that mimicking falling leaves is an adaptation that functions to reduce predation by birds.

  10. Spectrocolourimetry visualized differences in sexual skin colouration in macaques.

    PubMed

    Ono, Eiri; Suzuki, Juri; Ishida, Takafumi

    2015-01-01

    The females of some catarrhines develop conspicuous sexual skin transformations in their hind limbs. Among macaques (one of the radiated and adapted catarrhine groups with diversified sexual skin transformations), differences in sexual skin colouration between the Japanese macaque Macaca fuscata and the rhesus macaque M. mulatta have not been quantitatively analysed. In this study, the sexual skin colouration of these macaques was spectrocolourimetrically measured in the non-mating season (NMS) and the mating season (MS) and represented in a CIELAB space with the variables L*, a* and b*. The variables L*, a* and b* represent positions on the light-dark, red/magenta-green, and yellow-blue axes, respectively. In the Japanese macaques the average ± SD of L*, a* and b* was 53.61 ± 3.31, 11.51 ± 4.57 and 6.66 ± 2.25 in the NMS and 46.60 ± 2.78, 19.97 ± 2.99 and 8.80 ± 1.34 in the MS, respectively, while in the rhesus macaques the average ± SD of L*, a* and b* was 60.09 ± 3.96, 5.99 ± 4.59 and 5.83 ± 2.37 in the NMS and 52.70 ± 6.54, 13.62 ± 6.86 and 8.07 ± 1.43 in the MS, respectively. The sexual skin of the Japanese macaques was consistently much redder (larger a*) and darker (smaller L*) than that of the rhesus macaques. The smaller L* suggested a greater dermal melanin content in the Japanese macaques. These closely related macaque species have similar but distinct sexual skin colourations. Spectrocolourimetry is thus useful to suggest the histophysiological background of the colouration.

  11. Chameleons communicate with complex colour changes during contests: different body regions convey different information.

    PubMed

    Ligon, Russell A; McGraw, Kevin J

    2013-01-01

    Many animals display static coloration (e.g. of feathers or fur) that can serve as a reliable sexual or social signal, but the communication function of rapidly changing colours (as in chameleons and cephalopods) is poorly understood. We used recently developed photographic and mathematical modelling tools to examine how rapid colour changes of veiled chameleons Chamaeleo calyptratus predict aggressive behaviour during male-male competitions. Males that achieved brighter stripe coloration were more likely to approach their opponent, and those that attained brighter head coloration were more likely to win fights; speed of head colour change was also an important predictor of contest outcome. This correlative study represents the first quantification of rapid colour change using organism-specific visual models and provides evidence that the rate of colour change, in addition to maximum display coloration, can be an important component of communication. Interestingly, the body and head locations of the relevant colour signals map onto the behavioural displays given during specific contest stages, with lateral displays from a distance followed by directed, head-on approaches prior to combat, suggesting that different colour change signals may evolve to communicate different information (motivation and fighting ability, respectively).

  12. 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.

  13. Cyclic Colour Change in the Bearded Dragon Pogona vitticeps under Different Photoperiods

    PubMed Central

    Fan, Marie; Stuart-Fox, Devi; Cadena, Viviana

    2014-01-01

    The ability to change colour rapidly is widespread among ectotherms and has various functions including camouflage, communication and thermoregulation. The process of colour change can occur as an aperiodic event or be rhythmic, induced by cyclic environmental factors or regulated by internal oscillators. Despite the importance of colour change in reptile ecology, few studies have investigated the occurrence of a circadian rhythm in lizard pigmentation. Additionally, although colour change also entails changes in near-infrared reflectance, which may affect thermoregulation, little research has examined this part of the spectrum. We tested whether the bearded dragon lizard, Pogona vitticeps, displays an endogenous circadian rhythm in pigmentation changes that could be entrained by light/dark (LD) cycles and how light affected the relative change in reflectance in both ultraviolet-visible and near-infrared spectra. We subjected 11 lizards to four photoperiodic regimens: LD 12∶12; LD 6∶18; LD 18∶6 and DD; and measured their dorsal skin reflectance at 3-hour intervals for 72 hours after a habituation period. A proportion of lizards displayed a significant rhythm under constant darkness, with maximum reflectance occurring in the subjective night. This endogenous rhythm synchronised to the different artificial LD cycles, with maximum reflectance occurring during dark phases, but did not vary in amplitude. In addition, the total ultraviolet-visible reflectance in relation to the total near-infrared reflectance was significantly higher during dark phases than during light phases. We conclude that P. vitticeps exhibits a circadian pigmentation rhythm of constant amplitude, regulated by internal oscillators and that can be entrained by light/dark cycles. PMID:25354192

  14. Cyclic colour change in the bearded dragon Pogona vitticeps under different photoperiods.

    PubMed

    Fan, Marie; Stuart-Fox, Devi; Cadena, Viviana

    2014-01-01

    The ability to change colour rapidly is widespread among ectotherms and has various functions including camouflage, communication and thermoregulation. The process of colour change can occur as an aperiodic event or be rhythmic, induced by cyclic environmental factors or regulated by internal oscillators. Despite the importance of colour change in reptile ecology, few studies have investigated the occurrence of a circadian rhythm in lizard pigmentation. Additionally, although colour change also entails changes in near-infrared reflectance, which may affect thermoregulation, little research has examined this part of the spectrum. We tested whether the bearded dragon lizard, Pogona vitticeps, displays an endogenous circadian rhythm in pigmentation changes that could be entrained by light/dark (LD) cycles and how light affected the relative change in reflectance in both ultraviolet-visible and near-infrared spectra. We subjected 11 lizards to four photoperiodic regimens: LD 12:12; LD 6:18; LD 18:6 and DD; and measured their dorsal skin reflectance at 3-hour intervals for 72 hours after a habituation period. A proportion of lizards displayed a significant rhythm under constant darkness, with maximum reflectance occurring in the subjective night. This endogenous rhythm synchronised to the different artificial LD cycles, with maximum reflectance occurring during dark phases, but did not vary in amplitude. In addition, the total ultraviolet-visible reflectance in relation to the total near-infrared reflectance was significantly higher during dark phases than during light phases. We conclude that P. vitticeps exhibits a circadian pigmentation rhythm of constant amplitude, regulated by internal oscillators and that can be entrained by light/dark cycles.

  15. 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.

  16. 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

  17. Bees associate colour cues with differences in pollen rewards.

    PubMed

    Nicholls, Elizabeth; de Ibarra, Natalie Hempel

    2014-08-01

    In contrast to the wealth of knowledge concerning sucrose-rewarded learning, the question of whether bees learn when they collect pollen from flowers has been little addressed. The nutritional value of pollen varies considerably between species, and it may be that bees learn the features of flowers that produce pollen best suited to the dietary requirements of their larvae. It is still unknown, however, whether a non-ingestive reward pathway for pollen learning exists, and how foraging bees sense differences between pollen types. Here we adopt a novel experimental approach testing the learning ability of bees with pollen rewards. Bumblebees were reared under controlled laboratory conditions. To establish which pollen rewards are distinguishable, individual bees were given the choice of collecting two types of pollen, diluted to varying degrees with indigestible α-cellulose. Bees preferentially collected a particular pollen type, but this was not always the most concentrated sample. Preferences were influenced by the degree of similarity between samples and also by the period of exposure, with bees more readily collecting samples of lower pollen concentration after five trials. When trained differentially, bees were able to associate an initially less-preferred contextual colour with the more concentrated sample, whilst their pollen preferences did not change. Successful learning of contextual cues seems to maintain pollen foraging preferences over repeated exposures, suggesting that fast learning of floral cues may preclude continuous sampling and evaluation of alternative reward sources, leading to constancy in pollen foraging. PMID:24855678

  18. Bees associate colour cues with differences in pollen rewards.

    PubMed

    Nicholls, Elizabeth; de Ibarra, Natalie Hempel

    2014-08-01

    In contrast to the wealth of knowledge concerning sucrose-rewarded learning, the question of whether bees learn when they collect pollen from flowers has been little addressed. The nutritional value of pollen varies considerably between species, and it may be that bees learn the features of flowers that produce pollen best suited to the dietary requirements of their larvae. It is still unknown, however, whether a non-ingestive reward pathway for pollen learning exists, and how foraging bees sense differences between pollen types. Here we adopt a novel experimental approach testing the learning ability of bees with pollen rewards. Bumblebees were reared under controlled laboratory conditions. To establish which pollen rewards are distinguishable, individual bees were given the choice of collecting two types of pollen, diluted to varying degrees with indigestible α-cellulose. Bees preferentially collected a particular pollen type, but this was not always the most concentrated sample. Preferences were influenced by the degree of similarity between samples and also by the period of exposure, with bees more readily collecting samples of lower pollen concentration after five trials. When trained differentially, bees were able to associate an initially less-preferred contextual colour with the more concentrated sample, whilst their pollen preferences did not change. Successful learning of contextual cues seems to maintain pollen foraging preferences over repeated exposures, suggesting that fast learning of floral cues may preclude continuous sampling and evaluation of alternative reward sources, leading to constancy in pollen foraging.

  19. Colour stability of denture teeth submitted to different cleaning protocols and accelerated artificial aging.

    PubMed

    Freire, T S; Aguilar, F G; Garcia, L da Fonseca Roberti; Pires-de-Souza, F de Carvalho Panzeri

    2014-03-01

    Acrylic resin is widely used for artificial teeth manufacturing due to several important characteristics; however, this material do not present acceptable colour stability over the course of time. This study evaluated the effect of different cleaning protocols and accelerated artificial aging on colour stability of denture teeth made of acrylic resin. Sixty denture teeth in dark and light shades were used, and separated according to the treatment to which they were submitted. Results demonstrated that colour stability of artificial teeth is influenced by the cleaning solution and artificial aging, being dark teeth more susceptible to colour alteration than lighter ones.

  20. Influence of Different Drinks on the Colour Stability of Dental Resin Composites

    PubMed Central

    Topcu, Fulya Toksoy; Sahinkesen, Gunes; Yamanel, Kivanc; Erdemir, Ugur; Oktay, Elif Aybala; Ersahan, Seyda

    2009-01-01

    Objectives The objective of this study was to evaluate the discolouration effects of artificial saliva, granule lemon juice, coffee (without sugar), coca cola, sour cherry juice, fresh carrot juice and red wine on resin-based composite materials that are commonly used in restorative dentistry. Methods Colour of four brands of resin composites (Filtek Z 250 (3M Espe), Filtek Supreme (3M Espe), Quadrant (Cavex), Charisma (Heraeus-Kulzer)) of A2 shade was measured after one day of immersion in eight different solutions. Colour measurements were obtained by using a XL-20 Trismus Colourimeter and colour differences (ΔE) were estimated. For statistical evaluation, analysis of variance (ANOVA), Dunnett and Tukey tests were used at a significance level of 0.05. Results For the four restorative materials tested, the lowest ΔE values were observed in the artificial saliva, while ΔE values were the highest in red wine group. When comparing the four different restorative materials, Filtek Supreme exhibited the least colour changes whereas Filtek Z250 was the least colour-stable. Conclusions Dental resin composites and drinking solutions were significant factors that may affect the colour stability. After immersion for one day, all materials showed visible colour changes. The red wine solution exhibited more staining than others in three groups. Filtek Supreme showed significantly the least colour change due to its nano particle sizes. PMID:19262731

  1. 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.

  2. Wake surveys of different car-body shapes with coloured isopressure maps

    SciTech Connect

    Cogotti, A.

    1984-01-01

    A technique to map the wake behind passenger cars with different rear end configurations has been developed in the full-scale automotive wind tunnel ''Pininfarina''. It is based on the measurement of total pressure in the wake, using a probe which is driven by a large traversing gear. Results are presented as coloured isopressure maps. Tests have been carried out on a 1:2.5 scale car model with two different front ends and eight different rear ends. The attainable body configurations are likely to cover the majority of passenger car shapes. Wake surveys have been conducted at several distances behind each car model in order to see the wake development. The paper shows and analyzes the results obtained for these sixteen car model configurations; it also emphasizes what kind of information can be obtained by this wake survey technique.

  3. Online colour training system for dental students: a comprehensive assessment of different training protocols.

    PubMed

    Liu, M; Chen, L; Liu, X; Yang, Y; Zheng, M; Tan, J

    2015-04-01

    The purpose of this study was to evaluate the training effect and to determine the optimal training protocol for a recently developed online colour training system. Seventy students participated in the evaluation. They first completed a baseline test with shade guides (SGT) and the training system (TST), and then trained with one of the three system training methods (Basic colour training for group E1, Vitapan Classical for E2, and Vitapan 3D-Master for E3) or shade guides (group C1) for 4 days. The control group (C2) received no training. The same test was performed after training and they finally completed a questionnaire. The correct matches after training increased in three experimental groups and group C1. Among experimental groups, the greatest improvement of correct matching number was achieved by group E3 (4·00 ± 1·88 in SGT, 4·29 ± 2·73 in TST), followed by E2 (2·29 ± 2·73 in SGT, 3·50 ± 3·03 in TST) and E1 (2·00 ± 2·60 in SGT, 1·93 ± 2·96 in TST). The difference between E3 and E1 was statistically significant (P = 0·036 in SGT, 0·026 in TST). The total average training time was shorter in group E2 (15·39 ± 4·22 min) and E3 (17·63 ± 5·22 min), with no significant difference between them. Subjective evaluations revealed that self-confidence in colour matching were improved greater in group C1 and E3. In conclusion, all tested sections of the system effectively improved students' colour-matching ability. Among system training methods, Vitapan 3D-Master showed the best performance; it enabled greater shade-matching improvement, it saved time and was superior in subjective evaluations.

  4. Colour stability of three esthetic laminate materials against to different staining agents.

    PubMed

    Belli, S; Tanriverdi, F F; Belli, E

    1997-09-01

    The purpose of the present study was to evaluate the colour stability of three laminate veneer materials against to tea, coffee and cigarette smoke. 72 discs prepared by using two different type composite materials and a dental porcelain were divided into groups and immersed into distilled water, tea, Turkish coffee solutions. The last group was exposed to cigarette smoke. Colour differences were measured by colorimeter at the beginning and then in the period of 1 day, 1 week and 1 month respectively. As a result, it was found that cigarette smoke was the most staining agent, porcelain material was the most colour stable material, and indirect composite material was more colour stable than the direct one. PMID:9569793

  5. Colour stability of temporary restorations with different thicknesses submitted to artificial accelerated aging.

    PubMed

    Silame, F D J; Tonani, R; Alandia-Roman, C C; Chinelatti, M; Panzeri, H; Pires-de-Souza, F C P

    2013-12-01

    This study evaluated the colour stability of temporary prosthetic restorations with different thicknesses submitted to artificial accelerated aging. The occlusal surfaces of 40 molars were grinded to obtain flat enamel surfaces. Twenty acrylic resin specimens [Polymethyl methacrylate (Duralay) and Bis-methyl acrylate (Luxatemp)] were made with two different thicknesses, 0.5 mm and 1.0 mm. Temporary restorations were fixed on enamel and CIE L*a*b* colour parameters of each specimen were assessed before and after artificial accelerated aging. All groups showed colour alterations above the clinically acceptable limit. Luxatemp showed the lowest colour alteration regardless its thickness and Duralay showed the greatest alteration with 0.5 mm. PMID:24479216

  6. Colour stability of temporary restorations with different thicknesses submitted to artificial accelerated aging.

    PubMed

    Silame, F D J; Tonani, R; Alandia-Roman, C C; Chinelatti, M; Panzeri, H; Pires-de-Souza, F C P

    2013-12-01

    This study evaluated the colour stability of temporary prosthetic restorations with different thicknesses submitted to artificial accelerated aging. The occlusal surfaces of 40 molars were grinded to obtain flat enamel surfaces. Twenty acrylic resin specimens [Polymethyl methacrylate (Duralay) and Bis-methyl acrylate (Luxatemp)] were made with two different thicknesses, 0.5 mm and 1.0 mm. Temporary restorations were fixed on enamel and CIE L*a*b* colour parameters of each specimen were assessed before and after artificial accelerated aging. All groups showed colour alterations above the clinically acceptable limit. Luxatemp showed the lowest colour alteration regardless its thickness and Duralay showed the greatest alteration with 0.5 mm.

  7. 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. PMID:26003614

  8. Usage pattern and exposure assessment of food colours in different age groups of consumers in the State of Uttar Pradesh, India.

    PubMed

    Dixit, S; Purshottam, S K; Gupta, S K; Khanna, S K; Das, M

    2010-02-01

    The present study aims to investigate the nature and levels of colours in food items and to undertake risk assessment vis-a-vis intake among different age groups of consumers in the State of Uttar Pradesh, India. A total of 478 edible foodstuffs were analysed, and of six permitted colours, Sunset Yellow FCF (SSYFCF) and Tartrazine were most popular, and two non-permitted colours, namely Metanil Yellow and Rhodamine B, were encountered. The study showed a marked improvement in the trend of use of non-permitted colours over previous surveys, with 90% foods now resorting to approved food colours. However, 59% of foods employing permitted colours exceeded the maximum allowable limit, with average quantities crossing the threshold of 100 mg kg(-1) in most food commodities. The intake of SSYFCF exceeded the acceptable daily intake (ADI) for children and adolescents by 88% and 39%, respectively, and was statistically significant when analysed by error bars and distribution curves. In adults, SSYFCF saturated 59% of the ADI. For Carmoisine, Tartrazine and Ponceau 4R, saturation of ADI ranged from 27.4% to 90.3% in children and adolescents and from 10.8% to 47.6% in adult subjects. These results indicate that children and adolescents are more vulnerable to higher intakes of food colours compared with the adult population. Allowing a uniform level of all colours in foods under Indian rules, notwithstanding wide variations of 250-fold in their allocated ADIs, could be one reason for the higher intake and hence only technological need-based levels of individual colours are desired to be prescribed.

  9. Children's Sensitivity to Different Modes of Colour Use in Art.

    ERIC Educational Resources Information Center

    O'Hare, D.; Cook, Deborah

    1983-01-01

    Reviews studies of children's drawings and summarizes experiment which tested 5- to 11-year-olds for ability to execute color use differences and sensitivity to differences in heraldic, gradation, harmonic, and pure color use. It was found that children go from being completely unable to consistently able to produce appropriate differences. (MBR)

  10. Cryptic differences in colour among Müllerian mimics: how can the visual capacities of predators and prey shape the evolution of wing colours?

    PubMed

    Llaurens, V; Joron, M; Théry, M

    2014-03-01

    Antagonistic interactions between predators and prey often lead to co-evolution. In the case of toxic prey, aposematic colours act as warning signals for predators and play a protective role. Evolutionary convergence in colour patterns among toxic prey evolves due to positive density-dependent selection and the benefits of mutual resemblance in spreading the mortality cost of educating predators over a larger prey assemblage. Comimetic species evolve highly similar colour patterns, but such convergence may interfere with intraspecific signalling and recognition in the prey community, especially for species involved in polymorphic mimicry. Using spectrophotometry measures, we investigated the variation in wing coloration among comimetic butterflies from distantly related lineages. We focused on seven morphs of the polymorphic species Heliconius numata and the seven corresponding comimetic species from the genus Melinaea. Significant differences in the yellow, orange and black patches of the wing were detected between genera. Perceptions of these cryptic differences by bird and butterfly observers were then estimated using models of animal vision based on physiological data. Our results showed that the most strikingly perceived differences were obtained for the contrast of yellow against a black background. The capacity to discriminate between comimetic genera based on this colour contrast was also evaluated to be higher for butterflies than for birds, suggesting that this variation in colour, likely undetectable to birds, might be used by butterflies for distinguishing mating partners without losing the benefits of mimicry. The evolution of wing colour in mimetic butterflies might thus be shaped by the opposite selective pressures exerted by predation and species recognition.

  11. Cryptic differences in colour among Müllerian mimics: how can the visual capacities of predators and prey shape the evolution of wing colours?

    PubMed

    Llaurens, V; Joron, M; Théry, M

    2014-03-01

    Antagonistic interactions between predators and prey often lead to co-evolution. In the case of toxic prey, aposematic colours act as warning signals for predators and play a protective role. Evolutionary convergence in colour patterns among toxic prey evolves due to positive density-dependent selection and the benefits of mutual resemblance in spreading the mortality cost of educating predators over a larger prey assemblage. Comimetic species evolve highly similar colour patterns, but such convergence may interfere with intraspecific signalling and recognition in the prey community, especially for species involved in polymorphic mimicry. Using spectrophotometry measures, we investigated the variation in wing coloration among comimetic butterflies from distantly related lineages. We focused on seven morphs of the polymorphic species Heliconius numata and the seven corresponding comimetic species from the genus Melinaea. Significant differences in the yellow, orange and black patches of the wing were detected between genera. Perceptions of these cryptic differences by bird and butterfly observers were then estimated using models of animal vision based on physiological data. Our results showed that the most strikingly perceived differences were obtained for the contrast of yellow against a black background. The capacity to discriminate between comimetic genera based on this colour contrast was also evaluated to be higher for butterflies than for birds, suggesting that this variation in colour, likely undetectable to birds, might be used by butterflies for distinguishing mating partners without losing the benefits of mimicry. The evolution of wing colour in mimetic butterflies might thus be shaped by the opposite selective pressures exerted by predation and species recognition. PMID:24444083

  12. Colour stability of acrylic resin denture teeth after immersion in different beverages.

    PubMed

    Arana-Correa, B E; Sepúlveda-Navarro, W F; Florez, F L E; Urban, V M; Jorge, J H; Campanha, N H

    2014-06-01

    The colour stability of acrylic resin denture teeth in beverages was investigated. A spectrophotometer measured the colour (CIE-L*a*b* system) of all specimens after storage in distilled water/for 24 h at 37 degrees C (T0). Specimens were then immersed in various beverages. After 15 days (T1) and 30 days (T2), for each material, the mean deltaE values were calculated and compared by two-way ANOVA and Tukey intervals (alpha = 0.05). In the deltaT0T1 period, specimens stored in red wine were significantly discoloured, compared to distilled water (P = 0.003). There was no difference between immersion solutions in deltaET0T2 (P = 0.772) and in deltaET1T2 (P = 0.058), and no difference between materials in all immersion periods.

  13. 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.

  14. Discrete colour polymorphism in the tawny dragon lizard (Ctenophorus decresii) and differences in signal conspicuousness among morphs.

    PubMed

    Teasdale, L C; Stevens, M; Stuart-Fox, D

    2013-05-01

    Intraspecific colour variation is common in nature and can vary from the coexistence of discrete colour variants in polymorphic species to continuous variation. Whether coloration is continuous or discrete is often ambiguous and many species exhibit a combination of the two. The nature of the variation (discrete or continuous) has implications for both the genetic basis of the colour variation and the evolutionary processes generating and maintaining it. Consequently, it is important to qualify the existence of discrete morphs, particularly in relation to the animal's visual system. In this study, we quantified male throat colour variation in Ctenophorus decresii tawny dragon lizard and tested for morphological and ecological correlates of the colour variants. We confirmed that discrete throat colour morphs can be defined based on colour and pattern analyses independent of the human visual system. We also found that the colour variants differed in their conspicuousness from the background, to the lizard's visual system, which has implications for signalling. However, the morphs did not differ in morphology or microhabitat use, which suggests that these characteristics are not involved in the evolutionary maintenance of the polymorphism.

  15. Should a water colour parameter be included in lake total phosphorus prediction models used for the Water Framework Directive?

    PubMed

    Vinogradoff, Susan I; Oliver, Ian W

    2015-01-01

    Under the Water Framework Directive (WFD) lakes are classified according to a variety of criteria. This classification facilitates state of the environment assessments and helps identify work needed to achieve the objectives of the WFD, which are broadly to maintain and/or restore water quality and ecological status at a level recognised as good or high. To achieve high or good status, lakes must meet a criterion for total phosphorus (TP) that is linked to a predicted reference condition value that is derived by various models. Lakes which fail to meet good status may require expensive remedial actions to be undertaken, thus accurate identification of the reference condition TP concentration is vital for effective environmental management. However, the models currently employed could be improved for some regions, particularly those with carbon rich soils. By examining 19 reference condition lakes (i.e. lakes essentially non-impacted by humans) in peaty areas of Scotland, we found that a simple parameter linked to water colour and humic substances was a better predictor of TP than the currently employed models (R(2) 0.585 vs R(2) < 0.01). Therefore, for Scotland and elsewhere, in regions with carbon rich soils and lakes with humic waters the TP predictive models could be improved by development and incorporation of a parameter related to water colour and humic components.

  16. Influence of different blanching methods on colour, ascorbic acid and phenolics content of broccoli.

    PubMed

    Severini, C; Giuliani, R; De Filippis, A; Derossi, A; De Pilli, T

    2016-01-01

    Lack of nutrients in cooking water, high energetic costs, high water consumption and recycling are some drawbacks of vegetable blanching. Those disadvantages could be bypassed using microwave blanching. Three blanching methods (microwave, boiling water and steaming) were compared in this study in order to determine their effects on some functional properties of broccoli. In addition, the thermal damage on broccoli colour was evaluated. The effectiveness of each blanching process was performed measuring the lost of peroxidase activity, that results more rapidly in microwaves and steam treatments (50 and 60 s respectively) than in boiling water treatment (120 s). The colour indexes did not allow to discriminate a significant difference among treatments. The increase of treatment time caused a vitamin C decrease in samples blanched by boiling water and steam; this trend was not observed in microwaved samples. The phenols content did not significantly vary depending both on type and on time of treatment.

  17. Influence of different blanching methods on colour, ascorbic acid and phenolics content of broccoli.

    PubMed

    Severini, C; Giuliani, R; De Filippis, A; Derossi, A; De Pilli, T

    2016-01-01

    Lack of nutrients in cooking water, high energetic costs, high water consumption and recycling are some drawbacks of vegetable blanching. Those disadvantages could be bypassed using microwave blanching. Three blanching methods (microwave, boiling water and steaming) were compared in this study in order to determine their effects on some functional properties of broccoli. In addition, the thermal damage on broccoli colour was evaluated. The effectiveness of each blanching process was performed measuring the lost of peroxidase activity, that results more rapidly in microwaves and steam treatments (50 and 60 s respectively) than in boiling water treatment (120 s). The colour indexes did not allow to discriminate a significant difference among treatments. The increase of treatment time caused a vitamin C decrease in samples blanched by boiling water and steam; this trend was not observed in microwaved samples. The phenols content did not significantly vary depending both on type and on time of treatment. PMID:26787969

  18. 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.

  19. 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.

  20. 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. PMID:27221533

  1. Colour harmony of two colour combinations in clothes matching

    NASA Astrophysics Data System (ADS)

    Wicaksono, Sungging Haryo; Fu, Tzu-Hao; Chen, Liang-Ya; Hou, Chien-Yu; Ou, Li-Chen

    2015-01-01

    There are many definitions and theories about colour harmony. But no consistent rules and definitions can be determined. Some previous researches show that there are many factors that influence the colour harmony. Colour harmony is highly depends on the external factors, including the context of colour besides their colour combinations. In the current research an experiment conducted by observing two colour combinations which applied in shirt and trousers. Twenty observers involved in the experiment, consist of ten male and ten female. Each observer predict colour harmony score in 58 samples of shirt and trouser pairs, the colour combination then applied upside down. Based on the experimental results, male and female group has similar tendency in colour harmony score prediction in the same colour samples (correlation coefficient, r=0.84). Upside down colour combinations will change the impression of observer about colour harmony and yields a different value of colour harmony prediction score which indicated from correlation coefficient results of 0.53.

  2. Rethinking Colour Constancy.

    PubMed

    Logvinenko, Alexander D; Funt, Brian; Mirzaei, Hamidreza; Tokunaga, Rumi

    2015-01-01

    Colour constancy needs to be reconsidered in light of the limits imposed by metamer mismatching. Metamer mismatching refers to the fact that two objects reflecting metameric light under one illumination may reflect non-metameric light under a second; so two objects appearing as having the same colour under one illuminant can appear as having different colours under a second. Yet since Helmholtz, object colour has generally been believed to remain relatively constant. The deviations from colour constancy registered in experiments are usually thought to be small enough that they do not contradict the notion of colour constancy. However, it is important to determine how the deviations from colour constancy relate to the limits metamer mismatching imposes on constancy. Hence, we calculated metamer mismatching's effect for the 20 Munsell papers and 8 pairs of illuminants employed in the colour constancy study by Logvinenko and Tokunaga and found it to be so extensive that the two notions-metamer mismatching and colour constancy-must be mutually exclusive. In particular, the notion of colour constancy leads to some paradoxical phenomena such as the possibility of 20 objects having the same colour under chromatic light dispersing into a hue circle of colours under neutral light. Thus, colour constancy refers to a phenomenon, which because of metamer mismatching, simply cannot exist. Moreover, it obscures the really important visual phenomenon; namely, the alteration of object colours induced by illumination change. We show that colour is not an independent, intrinsic attribute of an object, but rather an attribute of an object/light pair, and then define a concept of material colour in terms of equivalence classes of such object/light pairs. We suggest that studying the shift in material colour under a change in illuminant will be more fruitful than pursuing colour constancy's false premise that colour is an intrinsic attribute of an object.

  3. Rethinking Colour Constancy

    PubMed Central

    Logvinenko, Alexander D.; Funt, Brian; Mirzaei, Hamidreza; Tokunaga, Rumi

    2015-01-01

    Colour constancy needs to be reconsidered in light of the limits imposed by metamer mismatching. Metamer mismatching refers to the fact that two objects reflecting metameric light under one illumination may reflect non-metameric light under a second; so two objects appearing as having the same colour under one illuminant can appear as having different colours under a second. Yet since Helmholtz, object colour has generally been believed to remain relatively constant. The deviations from colour constancy registered in experiments are usually thought to be small enough that they do not contradict the notion of colour constancy. However, it is important to determine how the deviations from colour constancy relate to the limits metamer mismatching imposes on constancy. Hence, we calculated metamer mismatching’s effect for the 20 Munsell papers and 8 pairs of illuminants employed in the colour constancy study by Logvinenko and Tokunaga and found it to be so extensive that the two notions—metamer mismatching and colour constancy—must be mutually exclusive. In particular, the notion of colour constancy leads to some paradoxical phenomena such as the possibility of 20 objects having the same colour under chromatic light dispersing into a hue circle of colours under neutral light. Thus, colour constancy refers to a phenomenon, which because of metamer mismatching, simply cannot exist. Moreover, it obscures the really important visual phenomenon; namely, the alteration of object colours induced by illumination change. We show that colour is not an independent, intrinsic attribute of an object, but rather an attribute of an object/light pair, and then define a concept of material colour in terms of equivalence classes of such object/light pairs. We suggest that studying the shift in material colour under a change in illuminant will be more fruitful than pursuing colour constancy’s false premise that colour is an intrinsic attribute of an object. PMID:26356217

  4. HI absorption towards low luminosity radio-loud AGNs of different accretion modes and WISE colours

    NASA Astrophysics Data System (ADS)

    Chandola, Yogesh; Saikia, D. J.

    2016-08-01

    HI absorption studies of active galaxies enable us to probe their circumnuclear regions and the general interstellar medium, and study the supply of gas which may trigger the nuclear activity. We investigated the detection rate of HI absorption on the nature of radio galaxies based on their emission-line spectra, nature of the host galaxies based on the WISE colours and their radio structure, which may help understand the different accretion modes. The highest detection rate of HI absorption is found in the `late-type' galaxies with WISE infrared colours W2-W3 > 2, which is typical of gas-rich systems, along with a compact radio structure. Almost all the high-excitation radio galaxies (HERGs) in our sample have W2-W3 > 2. The HI detection rate for low-excitation radio galaxies (LERGs) with W2-W3 > 2 and compact radio structure is high (~ 71 %). This is similar to compact HERGs with W2-W3 > 2 where, although the numbers are small, all three sources are detected with HI absorption. In HERGs, compact radio structure in the nuclear or circumnuclear region could give rise to absorption by gas in the dusty torus in addition to gas in the interstellar medium. However, higher specific star formation rate (sSFR) for the LERGs with W2-W3 > 2 suggests that HI absorption may be largely due to star-forming gas in their hosts.

  5. Effect of high pressure high temperature processing on the volatile fraction of differently coloured carrots.

    PubMed

    Kebede, Biniam T; Grauwet, Tara; Palmers, Stijn; Vervoort, Liesbeth; Carle, Reinhold; Hendrickx, Marc; Van Loey, Ann

    2014-06-15

    To get deeper insight into the effect of high pressure high temperature (HPHT) processing on the volatile fraction of carrots, differently coloured cultivars exhibiting orange, purple, red and yellow hues were investigated. The impact of HPHT sterilisation was compared with thermal sterilisation based on equivalent microbiological inactivation. The results of this study demonstrated HPHT sterilisation to exert a distinct effect on important chemical reactions in comparison to thermal sterilisation. A comprehensive integration of MS-based metabolomic fingerprinting (HS-SPME-GC-MS) and chemometric tools has been implemented as an untargeted multivariate screening tool to identify differences. In all carrot cultivars, two dominant discriminative quality-related reactions were found: oxidative degradation and the Maillard reaction. Regarding the first reaction, oxidative terpenes, free fatty acids and carotenoids degradation products were detected at higher levels after HPHT sterilisation. Regarding the latter reaction, HPHT sterilisation appeared to suppress the formation of Maillard and Strecker degradation products.

  6. Measurement of surface temperature and emissivity of different materials by two-colour pyrometry.

    PubMed

    Raj, Vinay C; Prabhu, S V

    2013-12-01

    An experimental investigation is performed to substantiate the capability of a charge coupled device camera to measure local temperature and emissivity of different materials heated to temperatures above 500 °C by two-colour pyrometric technique using colorimetric method. Materials investigated are Inconel 718 with pyromark (high temperature paint), Inconel 718, stainless steel SS 304 and SS 316. Centerline temperature and emissivity distribution is obtained for target plates maintained at constant temperature by AC heating while complete temperature and emissivity distribution is provided for plates heated by flame impingement. The obtained results are compared with a calibrated infrared camera and thermocouples and the temperature distribution is found to be in close agreement. These results pertain to partially oxidized metal alloys covered in this study. Deviation in the measurement of emissivity can be attributed to its dependence on wavelength range, oxidation, and sensitivity of the image detector. PMID:24387454

  7. Measurement of surface temperature and emissivity of different materials by two-colour pyrometry.

    PubMed

    Raj, Vinay C; Prabhu, S V

    2013-12-01

    An experimental investigation is performed to substantiate the capability of a charge coupled device camera to measure local temperature and emissivity of different materials heated to temperatures above 500 °C by two-colour pyrometric technique using colorimetric method. Materials investigated are Inconel 718 with pyromark (high temperature paint), Inconel 718, stainless steel SS 304 and SS 316. Centerline temperature and emissivity distribution is obtained for target plates maintained at constant temperature by AC heating while complete temperature and emissivity distribution is provided for plates heated by flame impingement. The obtained results are compared with a calibrated infrared camera and thermocouples and the temperature distribution is found to be in close agreement. These results pertain to partially oxidized metal alloys covered in this study. Deviation in the measurement of emissivity can be attributed to its dependence on wavelength range, oxidation, and sensitivity of the image detector.

  8. Measurement of surface temperature and emissivity of different materials by two-colour pyrometry

    NASA Astrophysics Data System (ADS)

    Raj, Vinay C.; Prabhu, S. V.

    2013-12-01

    An experimental investigation is performed to substantiate the capability of a charge coupled device camera to measure local temperature and emissivity of different materials heated to temperatures above 500 °C by two-colour pyrometric technique using colorimetric method. Materials investigated are Inconel 718 with pyromark (high temperature paint), Inconel 718, stainless steel SS 304 and SS 316. Centerline temperature and emissivity distribution is obtained for target plates maintained at constant temperature by AC heating while complete temperature and emissivity distribution is provided for plates heated by flame impingement. The obtained results are compared with a calibrated infrared camera and thermocouples and the temperature distribution is found to be in close agreement. These results pertain to partially oxidized metal alloys covered in this study. Deviation in the measurement of emissivity can be attributed to its dependence on wavelength range, oxidation, and sensitivity of the image detector.

  9. Comparison of bending stiffness of six different colours of copolymer polypropylene.

    PubMed

    Ross, R S; Greig, R J; Convery, P

    1999-04-01

    This paper compares the bending stiffness of 5 different colours of copolymer polypropylene (CCP) with that of natural copolymer polypropylene (NCP). Flesh coloured and natural sheets are supplied thicker than other pigmented sheet. The bending stiffness of a specimen may be defined as EI, i.e. the product of E, Young's modulus of elasticity and I, the 2nd moment of area. Strips of "as supplied" (AS) and "post-draped" (PD) specimen were clamped and subjected to bending to assess the effect of pigmentation on bending characteristics. The gradient of the graph of bending deflection delta versus bending moment enables EI to be estimated. The process of thermoforming polypropylene reduces EI, the bending stiffness. However, the manual draping and vacuum procedure introduces so many variables that it is difficult to quantify the effect of pigmentation. The E of a bent specimen may be estimated from the gradient of the graph of deltaI versus bending moment. In the case of AS sheet, the effect of pigmentation on E is inconclusive. PD specimens indicate a significant reduction in E due to thermoforming. This was verified by an electron-microscope study of AS and PD specimens. Draping an ankle-foot orthosis (AFO) results in a non-uniform wall thickness. The results of this study with respect to the effects of pigmentation on the bending stiffness of AFOs are inconclusive. More detailed studies require to be completed in order to confirm which factors are responsible for this non-uniformity in wall thickness and consequent variation in bending stiffness. PMID:10355646

  10. Effect of colouring green stage zirconia on the adhesion of veneering ceramics with different thermal expansion coefficients

    PubMed Central

    Aktas, Guliz; Sahin, Erdal; Vallittu, Pekka; Özcan, Mutlu; Lassila, Lippo

    2013-01-01

    This study evaluated the adhesion of zirconia core ceramics with their corresponding veneering ceramics, having different thermal expansion coefficients (TECs), when zirconia ceramics were coloured at green stage. Zirconia blocks (N=240; 6 mm×7 mm×7 mm) were manufactured from two materials namely, ICE Zirconia (Group 1) and Prettau Zirconia (Group 2). In their green stage, they were randomly divided into two groups. Half of the specimens were coloured with colouring liquid (shade A2). Three different veneering ceramics with different TEC (ICE Ceramic, GC Initial Zr and IPS e.max Ceram) were fired on both coloured and non-coloured zirconia cores. Specimens of high noble alloys (Esteticor Plus) veneered with ceramic (VM 13) (n=16) acted as the control group. Core–veneer interface of the specimens were subjected to shear force in the Universal Testing Machine (0.5 mm⋅min−1). Neither the zirconia core material (P=0.318) nor colouring (P=0.188) significantly affected the results (three-way analysis of variance, Tukey's test). But the results were significantly affected by the veneering ceramic (P=0.000). Control group exhibited significantly higher mean bond strength values (45.7±8) MPa than all other tested groups ((27.1±4.1)−(39.7±4.7) and (27.4±5.6)−(35.9±4.7) MPa with and without colouring, respectively) (P<0.001). While in zirconia–veneer test groups, predominantly mixed type of failures were observed with the veneering ceramic covering <1/3 of the substrate surface, in the metal–ceramic group, veneering ceramic was left adhered >1/3 of the metal surface. Colouring zirconia did not impair adhesion of veneering ceramic, but veneering ceramic had a significant influence on the core–veneer adhesion. Metal–ceramic adhesion was more reliable than all zirconia–veneer ceramics tested. PMID:24158142

  11. Effect of colouring green stage zirconia on the adhesion of veneering ceramics with different thermal expansion coefficients.

    PubMed

    Aktas, Guliz; Sahin, Erdal; Vallittu, Pekka; Ozcan, Mutlu; Lassila, Lippo

    2013-12-01

    This study evaluated the adhesion of zirconia core ceramics with their corresponding veneering ceramics, having different thermal expansion coefficients (TECs), when zirconia ceramics were coloured at green stage. Zirconia blocks (N=240; 6 mm×7 mm×7 mm) were manufactured from two materials namely, ICE Zirconia (Group 1) and Prettau Zirconia (Group 2). In their green stage, they were randomly divided into two groups. Half of the specimens were coloured with colouring liquid (shade A2). Three different veneering ceramics with different TEC (ICE Ceramic, GC Initial Zr and IPS e.max Ceram) were fired on both coloured and non-coloured zirconia cores. Specimens of high noble alloys (Esteticor Plus) veneered with ceramic (VM 13) (n=16) acted as the control group. Core-veneer interface of the specimens were subjected to shear force in the Universal Testing Machine (0.5 mm⋅min(-1)). Neither the zirconia core material (P=0.318) nor colouring (P=0.188) significantly affected the results (three-way analysis of variance, Tukey's test). But the results were significantly affected by the veneering ceramic (P=0.000). Control group exhibited significantly higher mean bond strength values (45.7±8) MPa than all other tested groups ((27.1±4.1)-(39.7±4.7) and (27.4±5.6)-(35.9±4.7) MPa with and without colouring, respectively) (P<0.001). While in zirconia-veneer test groups, predominantly mixed type of failures were observed with the veneering ceramic covering <1/3 of the substrate surface, in the metal-ceramic group, veneering ceramic was left adhered >1/3 of the metal surface. Colouring zirconia did not impair adhesion of veneering ceramic, but veneering ceramic had a significant influence on the core-veneer adhesion. Metal-ceramic adhesion was more reliable than all zirconia-veneer ceramics tested.

  12. Infectious bronchitis virus and brown shell colour: Australian strains of infectious bronchitis virus affect brown eggshell colour in commercial laying hens differently.

    PubMed

    Samiullah, Sami; Roberts, Juliet; Chousalkar, Kapil

    2016-10-01

    The aim of the current study was to assess any effect of wild and vaccine Australian infectious bronchitis virus (IBV) strains on shell colour in brown-shelled eggs. In Experiment 1, eggs were collected from day 1 to day 13 post-inoculation (p.i.) from unvaccinated laying hens challenged with IBV wild strains T and N1/88 and from a negative control group of hens. In Experiment 2, eggs were collected from 2 to 22 days p.i. from unvaccinated and vaccinated laying hens challenged with either a wild or a vaccine strain of IBV. In Experiment 1, there was a significant effect (P < 0.05) of day p.i. and of viral strain on shell reflectivity, L* and protoporphyrin IX (PP IX) in eggshells, with and without cuticle. The mean PP IX/g of shell with and without cuticle was significantly higher on day 1 p.i. compared to day 7, after which PP IX increased with day p.i. In Experiment 2, shell reflectivity and L* increased and PP IX decreased with increased day p.i. until day 12. Shell reflectivity and L* decreased slightly after day 12 and increased again towards day 22. Shell reflectivity, L* and PP IX were not significantly different for eggshells from unvaccinated and vaccinated laying hens in the intact eggshell, but were significantly different in shells from which cuticle had been removed. In conclusion, the IBV strains reduced the intensity of brown shell colour to different extents with a lower amount of PP IX in eggshells.

  13. Impact of different colours of artificial light at night on melatonin rhythm and gene expression of gonadotropins in European perch.

    PubMed

    Brüning, Anika; Hölker, Franz; Franke, Steffen; Kleiner, Wibke; Kloas, Werner

    2016-02-01

    The distribution and intensity of artificial light at night, commonly referred to as light pollution, is consequently rising and progressively also ecological implications come to light. Low intensity light is known to suppress nocturnal melatonin production in several fish species. This study aims to examine the least suppressive light colour for melatonin excreted into the holding water and the influence of different light qualities and quantities in the night on gene expression of gonadotropins in fish. European perch (Perca fluviatilis) were exposed to light of different wavelengths during the night (blue, green, and red). Melatonin concentrations were measured from water samples every 3h during a 24h period. Gene expression of gonadotropins was measured in perch exposed to different light colours and was additionally examined for perch subjected to different intensities of white light (0 lx, 1 lx, 10 lx, 100 lx) during the night. All different light colours caused a significant drop of melatonin concentration; however, blue light was least suppressive. Gene expression of gonadotropins was not influenced by nocturnal light of different light colours, but in female perch gonadotropin expression was significantly reduced by white light already at the lowest level (1 lx). We conclude that artificial light with shorter wavelengths at night is less effective in disturbing biological rhythms of perch than longer wavelengths, coinciding with the light situation in freshwater habitats inhabited by perch. Different light colours in the night showed no significant effect on gonadotropin expression, but white light in the night can disturb reproductive traits already at very low light intensities. These findings indicate that light pollution has not only the potential to disturb the melatonin cycle but also the reproductive rhythm and may therefore have implications on whole species communities.

  14. Impact of different colours of artificial light at night on melatonin rhythm and gene expression of gonadotropins in European perch.

    PubMed

    Brüning, Anika; Hölker, Franz; Franke, Steffen; Kleiner, Wibke; Kloas, Werner

    2016-02-01

    The distribution and intensity of artificial light at night, commonly referred to as light pollution, is consequently rising and progressively also ecological implications come to light. Low intensity light is known to suppress nocturnal melatonin production in several fish species. This study aims to examine the least suppressive light colour for melatonin excreted into the holding water and the influence of different light qualities and quantities in the night on gene expression of gonadotropins in fish. European perch (Perca fluviatilis) were exposed to light of different wavelengths during the night (blue, green, and red). Melatonin concentrations were measured from water samples every 3h during a 24h period. Gene expression of gonadotropins was measured in perch exposed to different light colours and was additionally examined for perch subjected to different intensities of white light (0 lx, 1 lx, 10 lx, 100 lx) during the night. All different light colours caused a significant drop of melatonin concentration; however, blue light was least suppressive. Gene expression of gonadotropins was not influenced by nocturnal light of different light colours, but in female perch gonadotropin expression was significantly reduced by white light already at the lowest level (1 lx). We conclude that artificial light with shorter wavelengths at night is less effective in disturbing biological rhythms of perch than longer wavelengths, coinciding with the light situation in freshwater habitats inhabited by perch. Different light colours in the night showed no significant effect on gonadotropin expression, but white light in the night can disturb reproductive traits already at very low light intensities. These findings indicate that light pollution has not only the potential to disturb the melatonin cycle but also the reproductive rhythm and may therefore have implications on whole species communities. PMID:26584071

  15. Effect of temperature and air velocity on drying kinetics, antioxidant capacity, total phenolic content, colour, texture and microstructure of apple (var. Granny Smith) slices.

    PubMed

    Vega-Gálvez, Antonio; Ah-Hen, Kong; Chacana, Marcelo; Vergara, Judith; Martínez-Monzó, Javier; García-Segovia, Purificación; Lemus-Mondaca, Roberto; Di Scala, Karina

    2012-05-01

    The aim of this work was to study the effect of temperature and air velocity on the drying kinetics and quality attributes of apple (var. Granny Smith) slices during drying. Experiments were conducted at 40, 60 and 80°C, as well as at air velocities of 0.5, 1.0 and 1.5ms(-1). Effective moisture diffusivity increased with temperature and air velocity, reaching a value of 15.30×10(-9)m(2)s(-1) at maximum temperature and air velocity under study. The rehydration ratio changed with varying both air velocity and temperature indicating tissue damage due to processing. The colour difference, ΔE, showed the best results at 80°C. The DPPH-radical scavenging activity at 40°C and 0.5ms(-1) showed the highest antioxidant activity, closest to that of the fresh sample. Although ΔE decreased with temperature, antioxidant activity barely varied and even increased at high air velocities, revealing an antioxidant capacity of the browning products. The total phenolics decreased with temperature, but at high air velocity retardation of thermal degradation was observed. Firmness was also determined and explained using glass transition concept and microstructure analysis. PMID:26434262

  16. Colour vision deficiency.

    PubMed

    Simunovic, M P

    2010-05-01

    Colour vision deficiency is one of the commonest disorders of vision and can be divided into congenital and acquired forms. Congenital colour vision deficiency affects as many as 8% of males and 0.5% of females--the difference in prevalence reflects the fact that the commonest forms of congenital colour vision deficiency are inherited in an X-linked recessive manner. Until relatively recently, our understanding of the pathophysiological basis of colour vision deficiency largely rested on behavioural data; however, modern molecular genetic techniques have helped to elucidate its mechanisms. The current management of congenital colour vision deficiency lies chiefly in appropriate counselling (including career counselling). Although visual aids may be of benefit to those with colour vision deficiency when performing certain tasks, the evidence suggests that they do not enable wearers to obtain normal colour discrimination. In the future, gene therapy remains a possibility, with animal models demonstrating amelioration following treatment.

  17. The Tooth and Skin Colour Interrelationship across the Different Ethnic Groups

    PubMed Central

    Haralur, Satheesh B.; Dibas, Ahmed Mohammed; Almelhi, Nabil Abdullah; Al-Qahtani, Dhafer Ali

    2014-01-01

    Objectives. The purpose of the study was to investigate the relation between skin and tooth colour parameters in various ethnic groups. Materials and Methods. Saudi Arabian, Indian, African, and East Asian ethnic groups of 75 each were included in the study. The tooth colour was determined by spectrophotometer in CIELAB parameters. The skin colour was measured at earlobe, forehead, and malar locations by clinical skin photography. The data was statistically analysed by one-way ANOVA and correlation tests. Results. The “L” vale for the Saudi Arabian group had a strong correlation at earlobe location (r = 0.275), while correlation was found at forehead (r = 0.271) and malar region (r = 0.261) with Indian ethnic group. A strong negative correlation was observed in African ethnic group at all three locations for “L” parameter. The redness value “a” is found to have strong negative linear correlation between the earlobe and tooth for Saudi Arabian (r = −0.240) and Indian ethnic groups (r = −0.268). The “b” showed no correlation with skin location in all groups except positive correlation in African ethnic groups. Conclusions. The strong correlation was found between the skin and tooth colour parameters; hence the skin colour can be used as a guide for artificial tooth selection in edentulous patients. PMID:25101125

  18. Genetics of eye colours in different rural populations on the Silk Road.

    PubMed

    Ulivi, Sheila; Mezzavilla, Massimo; Gasparini, Paolo

    2013-11-01

    Eye colour is a highly transmissible and discernible trait in humans. A genome-wide association scan for variants associated to eye pigmentation was carried out on a large group of individuals coming from the Silk Road. Significant associations were detected not only with HERC2 (P-value=4.99 × 10(-37)) and OCA2 (P-value=4.51 × 10(-9)) genes but also with CTNNA2 gene (P-value=4.06 × 10(-8)). Moreover, the multifactor dimensionality reduction analysis clearly showed the effect of HERC2 haplotype over OCA2 mostly associated with SNP, thus enabling a highly accurate eye-colour prediction. Finally, the regression tree analysis showed that individuals carrying a given combination of haplotypes have a significant probability to show a blue or green/grey iris colour as compared with brown, with a gradient from west to east.

  19. Colour and antioxidant capacity stability in grape, strawberry and plum peel model juices at different pHs and temperatures.

    PubMed

    Hernández-Herrero, J A; Frutos, M J

    2014-07-01

    The aim of the study was to evaluate the anthocyanin sources potential as natural food colouring. Model juices (MJs) of grape, strawberry and plum peel were stored during 8weeks in darkness at 6 and 23°C. The colour stability was evaluated at pH 2.4, 3.1, 4.0, 5.0, 6.0, 7.0 and 8.1, and the antioxidant capacity at pH 4.0. The plum peel MJ showed the best and more stable colour parameters. The grape MJs presented a high stability although the chroma values were very low. The storage of strawberry MJ demonstrated a low stability at 23°C. The vitamin C equivalent antioxidant capacity in grape, strawberry and plum peel MJs was 7, 40 and 50mg/L, respectively. The strawberry MJ stability was very low. Total phenolics and anthocyanins ranged between 18-101 and 2-62mg/L of MJ, respectively. The determination coefficient was R(2)=0.745 between the antioxidant capacity and total phenolics.

  20. Is colour cognitive?

    NASA Astrophysics Data System (ADS)

    Skorupski, Peter; Chittka, Lars

    2011-03-01

    In recent years, colour-vision abilities have been rather generously ascribed to various invertebrates and even bacteria. This uncertainty of when to diagnose colour vision stems in part from confusing what colour vision can do with what it is. What colour vision can do is discriminate wavelength independent of intensity. However, if we take this as a definition of what colour vision is, then we might be obliged to conclude that some plants and bacteria have colour vision. Moreover, there is a similar confusion of what are necessary and what are sufficient mechanisms and behavioural abilities for colour vision. To humans, seeing in colour means seeing an image in which objects/lights have chromatic attributes—in contrast to the sensation that we have when viewing monochrome movies, or our experience in dim light when only rod vision is possible. The necessary basic equipment for this is to have at least two types of photoreceptors that differ in spectral sensitivity, and at least one type of spectrally opponent cell to compare the signals from the photoreceptors. Clearly, however, a necessary additional prerequisite for colour vision is to have vision, which entails the identification of shapes, sizes and locations of objects in the world. Thus, if an animal has colour vision, it should see an image in which distinct objects/lights have colour attributes. This distinguishes colour vision from wavelength discrimination, but also from what has historically been called wavelength-specific behaviour: a type of behaviour triggered by fixed configurations of spectral receptor signals; however, we discuss difficulties in diagnosing wavelength-specific behaviour as an indicator of the absence of colour vision. Finally, we discuss whether colour vision, by definition, contains a cognitive dimension for ordering and classifying perceptual experience.

  1. Paper Colouration

    NASA Astrophysics Data System (ADS)

    McLow, Barry

    Of all the products added to paper, colour is often seen as the least important as, generally speaking, it adds nothing to the final properties of the paper. However, incorrect use of colour can turn paper, which would meet all the physical properties required of it, into paper which is unsuitable for sale, purely and simply because it is the wrong colour or shade. Correct use of colour, therefore, is of utmost importance to the papermaker.

  2. Multi-coloured stereograms unveil two binocular colour mechanisms in human vision.

    PubMed

    Erkelens, Casper J; van Ee, Raymond

    2002-04-01

    Two different colours, one presented to one eye and the other presented to the other eye, often create the impression of a third colour. This percept is known as binocular colour mixture. Here we use coloured stereograms to study binocular colour appearance. Vivid pastel colours are induced in monocular, achromatic patches, if these are placed in stereograms whose left and right images differ in colour. The build-up of the colours is slow and takes tens of seconds or even minutes in certain individuals. The induced colours remain visible during monocular viewing of the patch and decay gradually. The same colours are induced irrespective of whether the patches are placed in fusible or rivalrous stereograms. We show that these colour effects cannot be induced by monocular colour mechanisms, either alone or in combination with binocular colour mixing. We suggest that the colours are induced by a binocular feedback mechanism, which reduces colour differences between the colour appearances of two monocular images. Induced colours are not observed if the achromatic patches are binocular. However, induced colours are apparent if one switches to monocular viewing after prolonged binocular viewing of the binocular patches. This aftereffect suggests that binocular colour induction acts on the monocular representations of binocular images. We suggest that during binocular viewing the fast process of binocular colour mixing masks the changes in colour appearance produced by the much slower process of binocular colour induction.

  3. Why birds eat colourful grit: colour preferences revealed by the colour of gizzard stones.

    PubMed

    Møller, A P; Erritzøe, J

    2010-03-01

    Colour preferences from sexual or social contexts are assumed to have arisen owing to preferences for specific kinds of food, representing a sensory bias, but once colour preferences have evolved in a sexual context, they may also be expressed during foraging. We tested whether preferences for specific body colours (i.e. plumage and soft parts) were related to colour preferences for grit ingested by birds. Birds eat grit to facilitate break down of food by the gizzard, and this function is independent of the colour of grit, but depends on the physical properties of stones. Bird species were significantly consistent in colour of grit, and grit of different colours varied in prevalence among species, even when analyses were restricted to a sample from a single locality. There were positive correlations between presence of lilac and red grit in the gizzard and presence of sexually dichromatic lilac and red colour on the body. There was a positive correlation between red grit colour and red sexually monochromatic body colour. Bird species with many different sexual colours, but not sexually monochromatic colours on their body had many different colours of grit. Males had more lilac and red grit than females, with this effect differing among species, whereas that was not the case for grit of other colours. These findings are consistent with the sensory bias hypothesis that birds express preferences for grit of specific colours and a high diversity of colours related to sexual colouration of the body, even when the colour of such grit is only visible to the individual at the moment of ingestion.

  4. Colour contribution to children's wayfinding in school environments

    NASA Astrophysics Data System (ADS)

    Helvacıoǧlu, Elif; Olguntürk, Nilgün

    2011-03-01

    The purpose of this study was to explore the contribution of colour to children's wayfinding ability in school environments and to examine the differences between colours in terms of their remembrance and usability in route learning process. The experiment was conducted with three different sample groups for each of three experiment sets differentiated by their colour arrangement. The participants totalled 100 primary school children aged seven and eight years old. The study was conducted in four phases. In the first phase, the participants were tested for familiarity with the experiment site and also for colour vision deficiencies by using Ishihara's tests for colour-blindness. In the second phase, they were escorted on the experiment route by the tester one by one, from one starting point to one end point and were asked to lead the tester to the end point by the same route. In the third phase, they were asked to describe verbally the route. In the final phase, they were asked to remember the specific colours at their correct locations. It was found that colour has a significant effect on children's wayfinding performances in school environments. However, there were no differences between different colours in terms of their remembrances in route finding tasks. In addition, the correct identifications of specific colours and landmarks were dependent on their specific locations. Contrary to the literature, gender differences were not found to be significant in the accuracy of route learning performances.

  5. Effect of soybean meal substitution by different concentrations of sunflower meal on egg quality traits of white and coloured dwarf dam lines.

    PubMed

    Das, S K; Biswas, A; Neema, R P; Maity, B

    2010-06-01

    1. The effect of soybean meal substitution by different concentrations of sunflower meal on egg quality traits of white and coloured dwarf dam lines was investigated. 2. A total of 144 dwarf hens (38 weeks of age) from the same hatch were randomly divided into 12 groups of 12 birds (4 dietary treatments x 3 replicates). 3. A 2 x 4 factorial design was used to study the effect of 2 lines (Factor A) and substitution of soybean meal (SBM) with 4 concentrations (0, 10, 15 and 20%) of sunflower meal (SFM) [Factor B] on egg quality traits of dwarf dam line hens. 4. All the diets were designed to be isocaloric (113 MJ ME/kg) and isonitrogenous (180 g/kg crude protein) The duration of the experiment was 12 weeks. 5. Analysis of variance indicated a highly significant line effect. There were non-significant effects of substitution of soybean meal with different concentrations of sunflower meal on egg quality traits except for Haugh unit. 6. White plumaged dwarf broiler breeder dam line produced significantly fewer, but larger, eggs than coloured dwarf dam line hens. PMID:20680878

  6. Colour detection thresholds in faces and colour patches.

    PubMed

    Tan, Kok Wei; Stephen, Ian D

    2013-01-01

    Human facial skin colour reflects individuals' underlying health (Stephen et al 2011 Evolution & Human Behavior 32 216-227); and enhanced facial skin CIELab b* (yellowness), a* (redness), and L* (lightness) are perceived as healthy (also Stephen et al 2009a International Journal of Primatology 30 845-857). Here, we examine Malaysian Chinese participants' detection thresholds for CIELab L* (lightness), a* (redness), and b* (yellowness) colour changes in Asian, African, and Caucasian faces and skin coloured patches. Twelve face photos and three skin coloured patches were transformed to produce four pairs of images of each individual face and colour patch with different amounts of red, yellow, or lightness, from very subtle (deltaE = 1.2) to quite large differences (deltaE = 9.6). Participants were asked to decide which of sequentially displayed, paired same-face images or colour patches were lighter, redder, or yellower. Changes in facial redness, followed by changes in yellowness, were more easily discriminated than changes in luminance. However, visual sensitivity was not greater for redness and yellowness in nonface stimuli, suggesting red facial skin colour special salience. Participants were also significantly better at recognizing colour differences in own-race (Asian) and Caucasian faces than in African faces, suggesting the existence of cross-race effect in discriminating facial colours. Humans' colour vision may have been selected for skin colour signalling (Changizi et al 2006 Biology Letters 2 217-221), enabling individuals to perceive subtle changes in skin colour, reflecting health and emotional status.

  7. Daily behaviour can differ between colour morphs of the same species: a study on circadian activity behaviour of grey and pied zebra finches.

    PubMed

    Mishra, Ila; Trivedi, Amit Kumar; Kumar, Vinod

    2014-05-01

    To investigate if the plumage colour mutation relates to circadian activity behaviour in the zebra finch, Taeniopygia guttata, wild type grey and pied mutant males were sequentially subjected for three weeks each to 12 h light:12 h darkness (12L:12D) and constant dim light (LL(dim)) condition. During the first 3 h of the 12 h day, pied finches were significantly greater active than grey finches. Also, as compared to grey, pied finches had longer activity duration in the day, with early activity onsets and late activity offsets. This was changed under free-running condition (LL(dim)), when the activity later in the subjective day (clock hour 9 and 11) was significantly greater in grey than in pied finches.Two colour morphs differed in daily activity profile, but not in the total daily activity or circadian rhythm period. Results suggest that greyzebra finches represent late chronotype, and could perhaps be better adapted to a seemingly stressful environment, such as low intensity LL(dim) in the present study.

  8. Resurgence of natural colourants: a holistic view.

    PubMed

    Kumar, J K; Sinha, A K

    2004-02-01

    Today, natural colourants are emerging globally, leaving synthetic colourants behind in the race, due to the realisation that are safer and ecofriendly in nature. In this context, a brief review of natural colourant sources, their classification, chemical constituents responsible for producing different colours, its activities and effect of different mordants on the hue is discussed.

  9. Colour vision: colouring the dark.

    PubMed

    Land, Michael F; Osorio, Daniel C

    2003-02-01

    Humans lose colour vision at night and it has often been assumed that this happens to other animals as well. It is not true of nocturnal moths, however: a recent study has shown that the elephant hawk moth makes use of trichromatic colour vision when seeking flowers by starlight.

  10. Unconventional colour vision.

    PubMed

    Marshall, Justin; Arikawa, Kentaro

    2014-12-15

    Butterflies and stomatopods are certainly outliers in their unconventional colour sense and despite some similarities at first glance, in fact sample the world of colour very differently. In one way, butterflies are relatively conventional, possessing either tri-or tetrachromatic colour vision, then just adding one or several task-specific sub-mechanisms onto this. It is the stomatopods so far that have really pushed the boat out into a different colour vision mechanism. Over 400 million years of independent evolution they have arrived at a solution with more in common with the way a satellite sensor examines the colours of the earth than other animals. Remember, however, that unconventional colour vision is not just the realm of the serially polychromatic. Apparently waterfleas with four classes of spectral receptors living in ponds operate a task-specific spectral sense with no need, or indeed neural processing power, to construct a complex discriminatory mechanism. It seems they have the butterfly added-extra set without the more complex comparative chromatic mechanisms, although in truth, conclusive behavioural proof is lacking. Behavioural observation of colour vision in the ecological context of each animal is vital before making the distinction between conventional and unconventional. Just counting spectral sensitivities is never enough.

  11. Hue-specific colour memory impairment in an individual with intact colour perception and colour naming.

    PubMed

    Jakobson, L S; Pearson, P M; Robertson, B

    2008-01-15

    Cases of hue-selective dyschomatopsias, together with the results of recent optical imaging studies [Xiao, Y., Casti, A. R. R., Xiao, J., & Kaplan, E. (2006). A spatially organized representation of colour in macaque primary visual cortex. Perception, 35, ECVP Abstract Supplement; Xiao, Y., Wang, Y., & Felleman, D. J. (2003). A spatially organized representation of colour in macaque cortical area V2. Nature, 421, 535-539], have provided support for the idea that different colours are processed in spatially distinct regions of extrastriate cortex. In the present report, we provide evidence suggesting that a similar, but distinct, map may exist for representations of colour in memory. This evidence comes from observations of a young woman (QP) who demonstrates an isolated deficit in colour memory secondary to a concussive episode. Despite having normal colour perception and colour naming skills, and above-average memory skills in other domains, QP's ability to recall visually encoded colour information over short retention intervals is dramatically impaired. Her long-term memory for colour and her colour imagery skills are also abnormal. Surprisingly, however, these impairments are not seen with all hues; specifically, her ability to remember or imagine blue shades is spared. This interesting case contributes to the literature suggesting that colour perception, naming, and memory can be clinically dissociated, and provides insights into the organization of colour information in memory.

  12. Hyperbolic geometry for colour metrics.

    PubMed

    Farup, Ivar

    2014-05-19

    It is well established from both colour difference and colour order perpectives that the colour space cannot be Euclidean. In spite of this, most colour spaces still in use today are Euclidean, and the best Euclidean colour metrics are performing comparably to state-of-the-art non-Euclidean metrics. In this paper, it is shown that a transformation from Euclidean to hyperbolic geometry (i.e., constant negative curvature) for the chromatic plane can significantly improve the performance of Euclidean colour metrics to the point where they are statistically significantly better than state-of-the-art non-Euclidean metrics on standard data sets. The resulting hyperbolic geometry nicely models both qualitatively and quantitatively the hue super-importance phenomenon observed in colour order systems.

  13. Plasmonic colour laser printing.

    PubMed

    Zhu, Xiaolong; Vannahme, Christoph; Højlund-Nielsen, Emil; Mortensen, N Asger; Kristensen, Anders

    2016-04-01

    Colour generation by plasmonic nanostructures and metasurfaces has several advantages over dye technology: reduced pixel area, sub-wavelength resolution and the production of bright and non-fading colours. However, plasmonic colour patterns need to be pre-designed and printed either by e-beam lithography (EBL) or focused ion beam (FIB), both expensive and not scalable processes that are not suitable for post-processing customization. Here we show a method of colour printing on nanoimprinted plasmonic metasurfaces using laser post-writing. Laser pulses induce transient local heat generation that leads to melting and reshaping of the imprinted nanostructures. Depending on the laser pulse energy density, different surface morphologies that support different plasmonic resonances leading to different colour appearances can be created. Using this technique we can print all primary colours with a speed of 1 ns per pixel, resolution up to 127,000 dots per inch (DPI) and power consumption down to 0.3 nJ per pixel. PMID:26657786

  14. Plasmonic colour laser printing

    NASA Astrophysics Data System (ADS)

    Zhu, Xiaolong; Vannahme, Christoph; Højlund-Nielsen, Emil; Mortensen, N. Asger; Kristensen, Anders

    2016-04-01

    Colour generation by plasmonic nanostructures and metasurfaces has several advantages over dye technology: reduced pixel area, sub-wavelength resolution and the production of bright and non-fading colours. However, plasmonic colour patterns need to be pre-designed and printed either by e-beam lithography (EBL) or focused ion beam (FIB), both expensive and not scalable processes that are not suitable for post-processing customization. Here we show a method of colour printing on nanoimprinted plasmonic metasurfaces using laser post-writing. Laser pulses induce transient local heat generation that leads to melting and reshaping of the imprinted nanostructures. Depending on the laser pulse energy density, different surface morphologies that support different plasmonic resonances leading to different colour appearances can be created. Using this technique we can print all primary colours with a speed of 1 ns per pixel, resolution up to 127,000 dots per inch (DPI) and power consumption down to 0.3 nJ per pixel.

  15. Colour measurements of surfaces to evaluate the restoration materials

    NASA Astrophysics Data System (ADS)

    Lo Monaco, Angela; Marabelli, Maurizio; Pelosi, Claudia; Picchio, Rodolfo

    2011-06-01

    In this paper two case studies on the application of colour measurements for the evaluation of some restoration materials are discussed. The materials related to the research are: watercolours employed in restoration of wall paintings and preservative/consolidants for wood artifacts. Commercial watercolours, supplied by Maimeri, Windsor&Newton and Talens factories have been tested. Colour measurements have been performed by means of a reflectance spectrophotometer (RS) before and after accelerated ageing of watercolours at 92% relative humidity (RH) and in a Solar Box chamber. The experimental results show that watercolours based on natural earths and artificial ultramarine undergo the main colour changes, expressed as L*, a* and b* variations and total colour difference (▵E*). In the other cases colour differences depend on both watercolour typology and suppliers. The other example concerns the evaluation of colour change due to surface treatment of Poplar (Populus sp.) and chestnut (Castanea sativa L.) wood samples. The wooden samples have been treated with a novel organic preservative/consolidant product that has been tested also in a real case as comparison. The treated samples have been artificially aged in Solar Box chamber equipped with a 280 nm UV filter. Colour has been measured before and after the artificial ageing by means of a RS. Colour changes have been determined also for the main door of an historical mansion in Viterbo, made of chestnut wood, and exposed outdoors.

  16. Colour blindness.

    PubMed

    Gordon, N

    1998-03-01

    The physiology of colour vision is discussed; as is the way in which the human eye can detect various combinations of red, green and blue. Red-green colour blindness, with X-linked inheritance, is the most common, but other types are also considered. Methods of testing relating to the age of the child are reviewed. The use of colours in teaching is widespread, but there is controversy over the difficulties this may cause a colour blind child. A review of the literature does not reveal much information on this, and any problems that do arise are likely to be individual to the child, and to depend on such factors as overall intelligence, the attitude of the teacher, and the personality of the child. There is not doubt that it is essential to recognise colour vision defects when it comes to choosing a career, and that tests must be done during secondary schooling, but in order to avoid some affected children being disadvantaged there is enough evidence to support testing at school entry.

  17. Diversity in human hair growth, diameter, colour and shape. An in vivo study on young adults from 24 different ethnic groups observed in the five continents.

    PubMed

    Loussouarn, Geneviève; Lozano, Isabelle; Panhard, Ségolène; Collaudin, Catherine; El Rawadi, Charles; Genain, Gilles

    2016-04-01

    Based on previous findings, from a worldwide study, classified the shapes of human hair into 8 major types, from straight to highly curly. This clearly extended the usual classification of hair into African, Asian or Caucasian types. However, determinations of hair growth parameters and hair density were excluded from such studies. To measure and compare the hair growth profiles of young adults without alopecia living in the five continents. 2249 young adults (18-35 years, females and males) without alopecia, originating from 24 various human ethnic groups were included in the study. Total hair density, telogen percentage and growth rate on three different scalp areas were measured, using non-invasive validated techniques. Natural hair colour level, curliness and hair diameter were additionally recorded, when practically possible. Diversity in hair growth parameters among the entire cohort was a key finding, with differences linked to scalp area, gender and geographic origin. Statistical approaches depicted African hair as having lower density and a slower growth rate. Asian hair showed a thicker diameter, with faster growth. Caucasian hair showed a high total hair density. On the one hand, this inter-continental study of hair growth parameters provides initial valuable base-line data on hair in young adults without alopecia, and on the other hand, further extends our knowledge of this unique human appendage, with some mosaic features, observed worldwide. PMID:27019510

  18. Diversity in human hair growth, diameter, colour and shape. An in vivo study on young adults from 24 different ethnic groups observed in the five continents.

    PubMed

    Loussouarn, Geneviève; Lozano, Isabelle; Panhard, Ségolène; Collaudin, Catherine; El Rawadi, Charles; Genain, Gilles

    2016-04-01

    Based on previous findings, from a worldwide study, classified the shapes of human hair into 8 major types, from straight to highly curly. This clearly extended the usual classification of hair into African, Asian or Caucasian types. However, determinations of hair growth parameters and hair density were excluded from such studies. To measure and compare the hair growth profiles of young adults without alopecia living in the five continents. 2249 young adults (18-35 years, females and males) without alopecia, originating from 24 various human ethnic groups were included in the study. Total hair density, telogen percentage and growth rate on three different scalp areas were measured, using non-invasive validated techniques. Natural hair colour level, curliness and hair diameter were additionally recorded, when practically possible. Diversity in hair growth parameters among the entire cohort was a key finding, with differences linked to scalp area, gender and geographic origin. Statistical approaches depicted African hair as having lower density and a slower growth rate. Asian hair showed a thicker diameter, with faster growth. Caucasian hair showed a high total hair density. On the one hand, this inter-continental study of hair growth parameters provides initial valuable base-line data on hair in young adults without alopecia, and on the other hand, further extends our knowledge of this unique human appendage, with some mosaic features, observed worldwide.

  19. Pitfalls in colour photography of choroidal tumours

    PubMed Central

    Schalenbourg, A; Zografos, L

    2013-01-01

    Colour imaging of fundus tumours has been transformed by the development of digital and confocal scanning laser photography. These advances provide numerous benefits, such as panoramic images, increased contrast, non-contact wide-angle imaging, non-mydriatic photography, and simultaneous angiography. False tumour colour representation can, however, cause serious diagnostic errors. Large choroidal tumours can be totally invisible on angiography. Pseudogrowth can occur because of artefacts caused by different methods of fundus illumination, movement of reference blood vessels, and flattening of Bruch's membrane and sclera when tumour regression occurs. Awareness of these pitfalls should prevent the clinician from misdiagnosing tumours and wrongfully concluding that a tumour has grown. PMID:23238442

  20. Pitfalls in colour photography of choroidal tumours.

    PubMed

    Schalenbourg, A; Zografos, L

    2013-02-01

    Colour imaging of fundus tumours has been transformed by the development of digital and confocal scanning laser photography. These advances provide numerous benefits, such as panoramic images, increased contrast, non-contact wide-angle imaging, non-mydriatic photography, and simultaneous angiography. False tumour colour representation can, however, cause serious diagnostic errors. Large choroidal tumours can be totally invisible on angiography. Pseudogrowth can occur because of artefacts caused by different methods of fundus illumination, movement of reference blood vessels, and flattening of Bruch's membrane and sclera when tumour regression occurs. Awareness of these pitfalls should prevent the clinician from misdiagnosing tumours and wrongfully concluding that a tumour has grown.

  1. 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. PMID:27023274

  2. 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.

  3. 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

  4. Complementary Colours for a Physicist

    ERIC Educational Resources Information Center

    Babic, Vitomir; Cepic, Mojca

    2009-01-01

    This paper reports on a simple experiment which enables splitting incident light into two different modes, each having a colour exactly complementary to the other. A brief historical development of colour theories and differences in a physicist's point of view with respect to an artist's one is discussed. An experimental system for producing…

  5. Covert colour processing in colour agnosia.

    PubMed

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

    2006-01-01

    Patients with colour agnosia can perceive colours and are able to match coloured patches on hue, but are unable to identify or categorise colours. It is a rare condition and there is as yet no agreement on the clinical definition or a generally accepted explanation. In line with observations from object agnosia and prosopagnosia, we hypothesised that (some of) these patients might still be able to process colour information at an implicit level. In this study, we investigated this possibility of implicit access to colour semantics and colour names in a man (MAH) who suffers from developmental colour agnosia. We designed two experimental computer tasks: an associative colour priming task with a lexical decision response and a reversed Stroop task. The results of these experiments suggest that there is indeed automatic processing of colour, although MAH was unable to explicitly use colour information.

  6. Colour Vision: Understanding #TheDress.

    PubMed

    Brainard, David H; Hurlbert, Anya C

    2015-06-29

    A widely-viewed image of a dress elicits striking individual variation in colour perception. Experiments with multiple variants of the image suggest that the individual differences may arise through the action of visual mechanisms that normally stabilise object colour.

  7. Comparative Evaluation of Frictional Properties, Load Deflection Rate and Surface Characteristics of Different Coloured TMA Archwires - An Invitro Study

    PubMed Central

    Aloysius, Arul Pradeep; Deepika; Soundararajan, Nagachandran Kandasamy; Manohar, Vijaykumar Neelam; Khan, Nayeemullah

    2015-01-01

    Introduction During tooth movement the success of sliding mechanics is dependent upon various factors which include frictional resistance at bracket-archwire interface, surface roughness of archwire materials and elastic properties of archwires. Ion implantation techniques reduce the frictional force and allow better tooth movement clinically. Aim The main objective of this study was to evaluate and compare the frictional properties, load deflection rate and surface characteristics of Honey dew and Purple coloured (Ion implanted) TMA wires with uncoated TMA wires. Materials and Methods Fifteen archwire samples were divided into three groups comprising of five samples in each group namely, Group I – Uncoated TMA wires (Control), Group II – Purple coloured TMA wires and Group III- Honey dew TMA wires. Friction and load deflection rate testing were performed with the Instron Universal testing machine and the surface characteristics of the wires were evaluated before and after sliding using Scanning Electron Microscope. Results The mean frictional characteristics and surface roughness for Honey dew TMA wires was lesser than Purple coloured TMA wires which was statistically significant. Both the coloured TMA wires showed low frictional characteristics and less surface roughness than uncoated TMA wires (the control). The mean load deflection rate was low for both coloured ion implanted TMA wires when compared to uncoated TMA wires which was statistically significant. Conclusion Coloured ion implanted TMA wires, especially Honey dew TMA wires have low friction, low load deflection rate and improved surface finish. Hence they can be used in frictionless as well as sliding mechanics, where uncoated TMA wires are inefficient. PMID:26816988

  8. Characterisation of viscosity, colour, 5-hydroxymethylfurfural content and diastase activity in raw rape honey (Brassica napus) at different temperatures.

    PubMed

    Kędzierska-Matysek, Monika; Florek, Mariusz; Wolanciuk, Anna; Skałecki, Piotr; Litwińczuk, Anna

    2016-04-01

    The effect of heating at various temperatures (30, 40, 50, 60, 70 and 80 °C) on dynamic viscosity, colour, 5-hydroxymethylfurfural (5-HMF) concentration and diastase activity of raw rape honey were assessed. In fresh honey, moisture, ash, free acidity, pH and electrical conductivity averaged 185.3 g kg(-1), 1.2 g kg(-1), 18.71 mEq kg(-1), 4.2 and 0.25 mS cm(-1), respectively. Heating significantly (p ≤ 0.05) increased lightness (L*), yellowness (b*), chroma (C*), hue (h°) values, but decreased redness (a*). The viscosity at 20 °C (33.6 Pa s) differed significantly (p ≤ 0.01) with those at 30, 40 and 50 °C (8.2, 2.5, and 1.6 Pa s, respectively). Diastase activity decreased concomitant with heating at higher temperatures. Honey heated at 80 °C for 15 min showed the maximum increase of 5-HMF content, with an average of 1.9 mg kg(-1) (62 %), compared to unheated samples. Heating for 15 min between 50 °C and 80 °C did not significantly degrade the quality of the honey, but, slightly enhanced formation of 5-HMF and reduced the diastase activity. PMID:27413239

  9. Evaluation of colour parameters and antioxidant activities of fruit wines.

    PubMed

    Kalkan Yildirim, Hatice

    2006-01-01

    The evaluation of oenological colorimetric indexes, CIELAB parameters, total phenols and antioxidant activities has been studied in different fruit wines made from black mulberry, blackberry, quince, apple, apricot, melon, red raspberry, bilberry, sour cherry and strawberry. The highest value of antioxidant activities and total phenolic contents were determined in bilberry, blackberry and black mulberry wines (61.80%, 1161 mg/l gallic acid equivalents; 60.00%, 1232 mg/l gallic acid equivalents; 58.10%, 1081 mg/l gallic acid equivalents), respectively. The highest values for A420 nm, A520 nm, A620 nm, the proportion of blue, wine colour, wine total colour of pigments, wine polymeric pigment colour and K-K values logarithmic colour intensity) were determined in bilberry fruit wine. Positive correlation was found between antioxidant activities and total phenols (r=0.958, P = 0.001). The results of grouping of different parameters in n-dimensional space with different fruit wines demonstrated the importance of bilberry, blackberry and black mulberry wines as natural antioxidants and colourants. PMID:16849114

  10. Colour-Difference Measurement Method for Evaluation of Quality of Electrolessly Deposited Copper on Polymer after Laser-Induced Selective Activation

    PubMed Central

    Gedvilas, Mindaugas; Ratautas, Karolis; Kacar, Elif; Stankevičienė, Ina; Jagminienė, Aldona; Norkus, Eugenijus; Li Pira, Nello; Račiukaitis, Gediminas

    2016-01-01

    In this work a novel colour-difference measurement method for the quality evaluation of copper deposited on a polymer is proposed. Laser-induced selective activation (LISA) was performed onto the surface of the polycarbonate/acrylonitrile butadiene styrene (PC/ABS) polymer by using nanosecond laser irradiation. The laser activated PC/ABS polymer was copper plated by using the electroless copper plating (ECP) procedure. The sheet resistance measured by using a four-point probe technique was found to decrease by the power law with the colour-difference of the sample images after LISA and ECP procedures. The percolation theory of the electrical conductivity of the insulator conductor mixture has been adopted in order to explain the experimental results. The new proposed method was used to determine an optimal set of the laser processing parameters for best plating conditions. PMID:26960432

  11. Colour-Difference Measurement Method for Evaluation of Quality of Electrolessly Deposited Copper on Polymer after Laser-Induced Selective Activation

    NASA Astrophysics Data System (ADS)

    Gedvilas, Mindaugas; Ratautas, Karolis; Kacar, Elif; Stankevičienė, Ina; Jagminienė, Aldona; Norkus, Eugenijus; Li Pira, Nello; Račiukaitis, Gediminas

    2016-03-01

    In this work a novel colour-difference measurement method for the quality evaluation of copper deposited on a polymer is proposed. Laser-induced selective activation (LISA) was performed onto the surface of the polycarbonate/acrylonitrile butadiene styrene (PC/ABS) polymer by using nanosecond laser irradiation. The laser activated PC/ABS polymer was copper plated by using the electroless copper plating (ECP) procedure. The sheet resistance measured by using a four-point probe technique was found to decrease by the power law with the colour-difference of the sample images after LISA and ECP procedures. The percolation theory of the electrical conductivity of the insulator conductor mixture has been adopted in order to explain the experimental results. The new proposed method was used to determine an optimal set of the laser processing parameters for best plating conditions.

  12. Colour-Difference Measurement Method for Evaluation of Quality of Electrolessly Deposited Copper on Polymer after Laser-Induced Selective Activation.

    PubMed

    Gedvilas, Mindaugas; Ratautas, Karolis; Kacar, Elif; Stankevičienė, Ina; Jagminienė, Aldona; Norkus, Eugenijus; Li Pira, Nello; Račiukaitis, Gediminas

    2016-01-01

    In this work a novel colour-difference measurement method for the quality evaluation of copper deposited on a polymer is proposed. Laser-induced selective activation (LISA) was performed onto the surface of the polycarbonate/acrylonitrile butadiene styrene (PC/ABS) polymer by using nanosecond laser irradiation. The laser activated PC/ABS polymer was copper plated by using the electroless copper plating (ECP) procedure. The sheet resistance measured by using a four-point probe technique was found to decrease by the power law with the colour-difference of the sample images after LISA and ECP procedures. The percolation theory of the electrical conductivity of the insulator conductor mixture has been adopted in order to explain the experimental results. The new proposed method was used to determine an optimal set of the laser processing parameters for best plating conditions.

  13. Primary posterior stabilized total knee arthroplasty: analysis of different instrumentation

    PubMed Central

    2014-01-01

    Background Intercondylar femoral bone removal during posterior stabilized (PS) total knee arthroplasty (TKA) makes many cruciate substituting implant designs less appealing than cruciate retaining implants. Bone stock conservation is considered fundamental in the prevision of future revision surgeries. The purpose of this study was to compare the quantity of intercondylar bone removable during PS housing preparation using three contemporary PS TKA instrumentations. Method We compared different box cutting jigs which were utilized for the PS housing of three popular PS knee prostheses. The bone removal area from every PS box cutting jig was three-dimensionally measured. Results Independently from the implant size, the cutting jig for a specific PS TKA always resected significantly less bone than the others: this difference was statistically significant, especially for small- to medium-sized total knee femoral components. Conclusion This study does not establish a clinical relevance of removing more or less bone at primary TKA, but suggests that if a PS design is indicated, it is preferable to select a model which possibly resects less distal femoral bone. PMID:25037275

  14. An RGB Approach to Prismatic Colours

    ERIC Educational Resources Information Center

    Theilmann, Florian; Grusche, Sascha

    2013-01-01

    Teaching prismatic colours usually boils down to establishing the take-home message that white light consists of "differently refrangible" coloured rays. This approach explains the classical spectrum of seven colours but has its limitations, e.g. in discussing spectra from setups with higher resolution or in understanding the well…

  15. Colour vision in billfish.

    PubMed Central

    Fritsches, K A; Partridge, J C; Pettigrew, J D; Marshall, N J

    2000-01-01

    Members of the billfish family are highly visual predatory teleosts inhabiting the open ocean. Little is known about their visual abilities in detail, but past studies have indicated that these fishes were likely to be monochromats. This study, however, presents evidence of two anatomically distinct cone types in billfish. The cells are arranged in a regular mosaic pattern of single and twin cones as in many fishes, and this arrangement suggests that the different cone types also show different spectral sensitivity, which is the basis for colour vision. First measurements using microspectrophotometry (MSP) revealed a peak absorption of the rod pigment at 484 nm, indicating that MSP, despite technical difficulties, will be a decisive tool in proving colour vision in these offshore fishes. When hunting, billfish such as the sailfish flash bright blue bars on their sides. This colour reflects largely in ultraviolet (UV) light at 350 nm as revealed by spectrophotometric measurements. Billfish lenses block light of wavelengths below 400 nm, presumably rendering the animal blind to the UV component of its own body colour. Interestingly, at least two prey species of billfish have lenses transmitting light in the UV waveband and are therefore likely to perceive a large fraction of the UV peak found in the blue bar of the sailfish. The possible biological significance of this finding is discussed. PMID:11079409

  16. Correlation between ethylene emission and skin colour changes during papaya (Carica papaya L.) fruit ripening

    NASA Astrophysics Data System (ADS)

    da Silva, M. G.; Oliveira, J. G.; Vitoria, A. P.; Corrêa, S. F.; Pereira, M. G.; Campostrini, E.; Santos, E. O.; Cavalli, A.; Vargas, H.

    2005-06-01

    The skin colour changes and ethylene emission rates were monitored during papaya (C. papaya L.) fruit ripening. Two groups of papaya (‘Formosa’ and ‘Solo’) were applied in this study. The total colour difference was used as measured parameter and the corresponding half time of its saturation was used as correlation parameter. A high correlation factor between the saturation half time and corresponding climacteric peak time was found. It was concluded that high ethylene emission rate in ‘Solo’ fruit promotes a quick change of the total colour difference.

  17. Total column density variations of ozone (O3) in presence of different types of clouds

    NASA Astrophysics Data System (ADS)

    Meena, G. S.

    2010-06-01

    The zenith sky scattered light spectra were carried out using zenith sky UV-visible spectrometer in clear and cloudy sky conditions during May-November 2000 over the tropical station Pune (18°32'N, 73°51'E). These scattered spectra are obtained in the spectral range 462-498 nm between 75° and 92° solar zenith angles (SZAs). The slant column densities (SCDs) as well as total column densities (TCDs) of NO2, O3, H2O and O4 are derived with different SZAs in clear and cloudy sky conditions. The large enhancements and reductions in TCDs of the above gases are observed in thick cumulonimbus (Cb) clouds and thin high cirrus (Ci) clouds, respectively, compared to clear sky conditions. The enhancements in TCDs of O3 appear to be due to photon diffusion, multiple Mie-scattering and multiple reflections between layered clouds or isolated patches of optically thick clouds. The reductions in TCDs due to optically thin clouds are noticed during the above period. The variations in TCDs of O3 measured under cloudy sky are discussed with total cloud cover (octas) of different types of clouds such as low clouds ( C L ), medium clouds ( C M ) and high clouds ( C H ) during May-November 2000. The variations in TCDs of O3 measured in cloudy sky conditions are found to be well matched with cloud sensitive parameter colour index (CI) and found to be in good correlation. The TCDcloudy are derived using airmass factors (AMFs) computed without considering cloud cover and CI in radiative transfer (RT) model, whereas TCDmodel are derived using AMFs computed with considering cloud cover, cloud height and CI in RT model. The TCDmodel is the column density of illuminated cloudy effect. A good agreement is observed between TCDmodel, TCDDob and TCDGOME.

  18. Changes in texture, colour and fatty acid composition of male and female pig shoulder fat due to different dietary fat sources.

    PubMed

    Hallenstvedt, E; Kjos, N P; Overland, M; Thomassen, M

    2012-03-01

    Two experiments with 72 slaughter pigs in each were conducted. Entire males and females were individually fed restricted. Palm kernel-, soybean- and fish-oil were used in varying combinations, giving different dietary fat levels (29-80g/kg) and iodine values ranging from 50 to 131. Shoulder fat was analysed for fatty acid composition (inner and outer layer), firmness and colour. A clear dose-response relationship was seen between fatty acids in diets and in shoulder fat. Interestingly, the very long chain n-3 fatty acids seemed to be deposited more efficiently when additional fat was included in the diet. Both high and low dietary iodine values changed towards less extreme iodine values in fat. Low-fat diets enhanced de novo synthesis of fatty acids. Males revealed a higher percentage of PUFA and a lower percentage of C18:1 and MUFA. Fat firmness, but not colour, was influenced by sex and dietary fat source.

  19. In vitro assessment of ultraviolet protection of coloured cotton knitted fabrics with different structures under stretched and wet conditions.

    PubMed

    Wong, W Y; Lam, J K C; Kan, C W; Postle, R

    2015-04-01

    Clothing provides intrinsic ultraviolet (UV) protection that can be improved by colouration. However, the daily wearing condition can undermine the UV protection of coloured clothing wherein garments are stretched by body movement and/or wetted by perspiration of wearers. Knitwear is an indispensable clothing in summer, but its UV protection against wearing conditions lacks extensive study especially in a fabric structural approach. This article aimed at narrowing the research gap by focusing on the UV protection against stretch and wetness provided by various knitted fabric constructions incorporating the knit, tuck and miss stitches. The results show that the black knitted fabrics exhibit a significant reduction in the UV protection factor by 53% on average at a 10% stretch level. Knitted fabrics with miss stitches retained good UV protection even when the fabrics were stretched by 20% of its original dimensions. PMID:25205834

  20. 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).

  1. 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). PMID:27664693

  2. Effect of different carotenoid-containing diets on the vitamin A levels and colour parameters in Iberian pigs' tissues: utility as biomarkers of traceability.

    PubMed

    Álvarez, R; Vicario, I M; Meléndez-Martínez, A J; Alcalde, M J

    2014-10-01

    Retinol and fat colour parameters in Iberian pigs fed on different carotenoid-containing diets were assessed. Thirty animals in two groups were considered: Iberian breed pigs fed on acorns and grass (Montanera) and on concentrate (Cebo). Carotenoids and retinoids were analysed in the diets and in plasma, liver and perirenal fat of the animals by HPLC and HPLC-MS. Retinol levels in plasma and fat were similar in Montanera and Cebo animals. The utility of retonids and colour parameters as traceability index was also explored. Retinoids in liver classified correctly 93% of the animals according to their diet L* and hab. CIELAB parameters of the perirenal fat discriminated correctly 78.6% of the animals according to their diet. L* values for the Montanera animals were significantly different (P<0.01) from those fed on concentrate. It can be claimed that the liver retinol profile and fat colour parameters can be useful for feeding traceability purposes in Iberian pigs breed in Montanera and Cebo.

  3. Molecular Characterisation of Colour Formation in the Prawn Fenneropenaeus merguiensis

    PubMed Central

    Ertl, Nicole G.; Elizur, Abigail; Brooks, Peter; Kuballa, Anna V.; Anderson, Trevor A.; Knibb, Wayne R.

    2013-01-01

    Introduction Body colouration in animals can have a range of functions, with predator protection an important aspect of colour in crustaceans. Colour determination is associated with the carotenoid astaxanthin, which is taken up through the diet and stabilised in the tissues by the protein crustacyanin. As a variety of genes are found to play a role in colour formation in other systems, a holistic approach was employed in this study to determine the factors involved in Fenneropenaeus merguiensis colouration. Results Full length F. merguiensis crustacyanin subunit A and C sequences were isolated. Crustacyanin subunit A and C were found in the F. merguiensis transcriptomes of the muscle/cuticle tissue, hepatopancreas, eye stalk and nervous system, using 454 next generation sequencing technology. Custom microarray analysis of albino, light and dark F. merguiensis cuticle tissue showed genes encoding actin, sarcoplasmic calcium-binding protein and arginine kinase to be 4-fold or greater differentially expressed (p<0.05) and down-regulated in albinos when compared to light and dark samples. QPCR expression analysis of crustacyanin and total astaxanthin pigment extraction revealed significantly (p<0.05) lower crustacyanin subunit A and C gene transcript copy numbers and total astaxanthin levels in albinos than in the light and dark samples. Additionally, crustacyanin subunit A and C expression levels correlated positively with each other. Conclusions This study identified gene products putatively involved in crustacean colouration, such as crustacyanin, sarcoplasmic calcium-binding protein and forms of actin, and investigated differences in gene expression and astaxanthin levels between albino, light and dark coloured prawns. These genes open a path to enhance our understanding of the biology and regulation of colour formation. PMID:23441225

  4. Health & nutritional implications of food colours.

    PubMed

    Babu, S; Shenolikar, I S

    1995-11-01

    Colour is a vital constituent of food which imparts distinct appearance to the food product. Artificial colouring becomes a technological necessity as foods tend to lose their natural shade during processing and storage. Most of the food colours tested in the conventional toxicity experiments showed toxic effects at a very high level of intake i.e., 1-5 per cent in the diet. However, such levels of intake are not normally encountered. Human studies indicated that food colours, (natural or synthetic) can induce wide range of allergic reactions only in sensitive or atopic individuals. Most of the foodborne diseases reported are due to the consumption of non-permitted textile colours or abuse of colours. The Government is pressurised periodically to place a total ban on the use of food colours due to their possible ill effects. It should be realised that surveillance should go hand in hand with legal actions.

  5. Comparison of three different methods of total carbon dioxide measurement.

    PubMed

    Kilborn, Susan H.; Bonnett, Brenda N.; Pook, Harold A.

    1995-01-01

    The objective of this study was to compare total carbon dioxide (TCO(2)) levels measured by three different methods. Two hundred jugular venous blood samples from dogs admitted to the Veterinary Teaching Hospital, Ontario Veterinary College with various clinical disorders were analyzed by the Radiometer blood gas analyzer (BGA) and the Coulter DACOS analyzer. In 70 of these samples, TCO(2) was also measured by the Kodak Ektachem DTE chemistry analyzer. Comparison of the agreement between methods revealed intraclass correlation coefficients (ICC) of 0.63, 0.79, and 0.82 for the DACOS-Ektachem, DACOS-BGA and Ektachem-BGA comparisons, respectively. Evaluation of the effect of storage time on TCO(2) content of stored serum samples measured on the DACOS analyzer revealed a decrease of almost 2 mmol/L and a decrease in the intraclass correlation coefficient values between the DACOS analyzer and other methods after 7 hours storage time. The results of this observational study revealed lower agreement between the three methods in this study than previously reported between other methods of TCO(2) measurement. Possible reasons for the lower than expected agreement in this study included changes in DACOS values because of storage and differences in methodologies between the methods.

  6. Missense and nonsense mutations in melanocortin 1 receptor (MC1R) gene of different goat breeds: association with red and black coat colour phenotypes but with unexpected evidences

    PubMed Central

    2009-01-01

    Background Agouti and Extension loci control the relative amount of eumelanin and pheomelanin production in melanocytes that, in turn, affects pigmentation of skin and hair. The Extension locus encodes the melanocortin 1 receptor (MC1R) whose permanent activation, caused by functional mutations, results in black coat colour, whereas other inactivating mutations cause red coat colour in different mammals. Results The whole coding region of the MC1R gene was sequenced in goats of six different breeds showing different coat colours (Girgentana, white cream with usually small red spots in the face; Maltese, white with black cheeks and ears; Derivata di Siria, solid red; Murciano-Granadina, solid black or solid brown; Camosciata delle Alpi, brown with black stripes; Saanen, white; F1 goats and the parental animals). Five single nucleotide polymorphisms (SNPs) were identified: one nonsense mutation (p.Q225X), three missense mutations (p.A81V, p.F250V, and p.C267W), and one silent mutation. The stop codon at position 225 should cause the production of a shorter MC1R protein whose functionality may be altered. These SNPs were investigated in a larger sample of animals belonging to the six breeds. The Girgentana breed was almost fixed for the p.225X allele. However, there was not complete association between the presence of red spots in the face and the presence of this allele in homozygous condition. The same allele was identified in the Derivata di Siria breed. However, its frequency was only 33%, despite the fact that these animals are completely red. The p.267W allele was present in all Murciano-Granadina black goats, whereas it was never identified in the brown ones. Moreover, the same substitution was present in almost all Maltese goats providing evidence of association between this mutation and black coat colour. Conclusion According to the results obtained in the investigated goat breeds, MC1R mutations may determine eumelanic and pheomelanic phenotypes. However

  7. Developmental colour agnosia.

    PubMed

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

    2007-08-01

    Colour agnosia concerns the inability to recognise colours despite intact colour perception, semantic memory for colour information, and colour naming. Patients with selective colour agnosia have been described and the deficit is associated with left hemisphere damage. Here we report a case study of a 43-year-old man who was referred to us with a stroke in his right cerebellar hemisphere. During the standard assessment it transpired that he was unable to name coloured patches. Detailed assessment of his colour processing showed that he suffers from a selective colour agnosia. As he claimed to have had this problem all his life, and the fact that the infratentorial infarct that he had incurred was in an area far away from the brain structures that are known to be involved in colour processing, we suggest that he is the first reported case of developmental colour agnosia.

  8. The uses of colour vision: behavioural and physiological distinctiveness of colour stimuli.

    PubMed Central

    Derrington, Andrew M; Parker, Amanda; Barraclough, Nick E; Easton, Alexander; Goodson, G R; Parker, Kris S; Tinsley, Chris J; Webb, Ben S

    2002-01-01

    Colour and greyscale (black and white) pictures look different to us, but it is not clear whether the difference in appearance is a consequence of the way our visual system uses colour signals or a by-product of our experience. In principle, colour images are qualitatively different from greyscale images because they make it possible to use different processing strategies. Colour signals provide important cues for segmenting the image into areas that represent different objects and for linking together areas that represent the same object. If this property of colour signals is exploited in visual processing we would expect colour stimuli to look different, as a class, from greyscale stimuli. We would also expect that adding colour signals to greyscale signals should change the way that those signals are processed. We have investigated these questions in behavioural and in physiological experiments. We find that male marmosets (all of which are dichromats) rapidly learn to distinguish between colour and greyscale copies of the same images. The discrimination transfers to new image pairs, to new colours and to image pairs in which the colour and greyscale images are spatially different. We find that, in a proportion of neurons recorded in the marmoset visual cortex, colour-shifts in opposite directions produce similar enhancements of the response to a luminance stimulus. We conclude that colour is, both behaviourally and physiologically, a distinctive property of images. PMID:12217169

  9. Colour discrimination and categorisation in Williams syndrome.

    PubMed

    Farran, Emily K; Cranwell, Matthew B; Alvarez, James; Franklin, Anna

    2013-10-01

    Individuals with Williams syndrome (WS) present with impaired functioning of the dorsal visual stream relative to the ventral visual stream. As such, little attention has been given to ventral stream functions in WS. We investigated colour processing, a predominantly ventral stream function, for the first time in nineteen individuals with Williams syndrome. Colour discrimination was assessed using the Farnsworth-Munsell 100 hue test. Colour categorisation was assessed using a match-to-sample test and a colour naming task. A visual search task was also included as a measure of sensitivity to the size of perceptual colour difference. Results showed that individuals with WS have reduced colour discrimination relative to typically developing participants matched for chronological age; performance was commensurate with a typically developing group matched for non-verbal ability. In contrast, categorisation was typical in WS, although there was some evidence that sensitivity to the size of perceptual colour differences was reduced in this group.

  10. The colour wheels of art, perception, science and physiology

    NASA Astrophysics Data System (ADS)

    Harkness, Nick

    2006-06-01

    Colour is not the domain of any one discipline be it art, philosophy, psychology or science. Each discipline has its own colour wheel and this presentation examines the origins and philosophies behind the colour circles of Art, Perception, Science and Physiology (after image) with reference to Aristotle, Robert Boyle, Leonardo da Vinci, Goethe, Ewald Hering and Albert Munsell. The paper analyses and discusses the differences between the four colour wheels using the Natural Colour System® notation as the reference for hue (the position of colours within each of the colour wheels). Examination of the colour wheels shows the dominance of blue in the wheels of art, science and physiology particularly at the expense of green. This paper does not consider the three-dimensionality of colour space its goal was to review the hue of a colour with regard to its position on the respective colour wheels.

  11. Colour Perception in ADHD

    ERIC Educational Resources Information Center

    Banaschewski, Tobias; Ruppert, Sinje; Tannock, Rosemary; Albrecht, Bjorn; Becker, Andreas; Uebel, Henrik; Sergeant, Joseph A.; Rothenberger, Aribert

    2006-01-01

    Attention-deficit/hyperactivity disorder (ADHD) is associated with unexplained impairments on speeded naming of coloured stimuli. These deficits may reflect hypofunctioning retinal dopaminergic mechanisms impairing particularly blue-yellow colour discrimination. Colour perception and rapid colour naming ability were investigated in 14 children…

  12. Evolution of colour vision in mammals.

    PubMed

    Jacobs, Gerald H

    2009-10-12

    Colour vision allows animals to reliably distinguish differences in the distributions of spectral energies reaching the eye. Although not universal, a capacity for colour vision is sufficiently widespread across the animal kingdom to provide prima facie evidence of its importance as a tool for analysing and interpreting the visual environment. The basic biological mechanisms on which vertebrate colour vision ultimately rests, the cone opsin genes and the photopigments they specify, are highly conserved. Within that constraint, however, the utilization of these basic elements varies in striking ways in that they appear, disappear and emerge in altered form during the course of evolution. These changes, along with other alterations in the visual system, have led to profound variations in the nature and salience of colour vision among the vertebrates. This article concerns the evolution of colour vision among the mammals, viewing that process in the context of relevant biological mechanisms, of variations in mammalian colour vision, and of the utility of colour vision.

  13. Total flavonoid content in varieties of Calendula officinalis L. originating from different countries and cultivated in Estonia.

    PubMed

    Raal, Ain; Kirsipuu, Kadri

    2011-03-01

    Total flavonoid contents in the inflorescences of different varieties of Calendula officinalis L. were investigated. The commercial seeds (20 samples) of varieties of C. officinalis originating from eight European countries were cultivated in home gardens in two different counties of Estonia. Total flavonoid contents, determined spectrophotometrically (λ = 370 nm), varied from each other by more than three times (0.21-0.68%) in the investigated varieties. The variety with the highest flavonoid content was 'Kablouna', produced by the Finnish company Siemen (0.68%). Other varieties with high flavonoid content, such as 'Touch of Red' produced by the Latvian company Kurzemes Seklas (0.55%), 'Golden Emperor' produced by the Finnish company Suvipiha (0.50%), 'Pomyk' from Poland (0.50%), etc., may also be preferred for cultivation as natural sources, as they are also rich in flavonoids. The amount of total flavonoids depends on the variety and/or the place and time of cultivation. There appeared to be no conclusive relationship between the total flavonoid content and the colour of ligulate and tubular florets of C. officinalis.

  14. Colour assortative pairing in a colour polymorphic lizard is independent of population morph diversity

    NASA Astrophysics Data System (ADS)

    Pérez i de Lanuza, Guillem; Font, Enrique; Carretero, Miguel Ángel

    2016-10-01

    Previous work with a colour polymorphic population of Podarcis muralis (Lacertidae) revealed that lizards pair by ventral colour, favouring the same colour (i.e. homomorphic) pairs. Such assortative pairing, which probably results in colour assortative mating, can have consequences for the genetic structure of the population and potentially promote speciation. The population previously studied, located in the Pyrenees, encompasses white, yellow and orange animals, as well as intermediate white-orange and yellow-orange morphs. However, other Pyrenean populations of P. muralis have less ventral colour morphs. Our aim in this study is to test the generality of the assortative colour pairing system, extending our previous analyses to populations with different morph compositions and frequencies. The results show that the assortative pattern of pairing is similar in all the populations analysed and, hence, independent of morph composition and not restricted to pentamorphic populations. This suggests that assortative pairing by colour is a general phenomenon for colour polymorphic populations of P. muralis.

  15. Colour assortative pairing in a colour polymorphic lizard is independent of population morph diversity.

    PubMed

    Pérez I de Lanuza, Guillem; Font, Enrique; Carretero, Miguel Ángel

    2016-10-01

    Previous work with a colour polymorphic population of Podarcis muralis (Lacertidae) revealed that lizards pair by ventral colour, favouring the same colour (i.e. homomorphic) pairs. Such assortative pairing, which probably results in colour assortative mating, can have consequences for the genetic structure of the population and potentially promote speciation. The population previously studied, located in the Pyrenees, encompasses white, yellow and orange animals, as well as intermediate white-orange and yellow-orange morphs. However, other Pyrenean populations of P. muralis have less ventral colour morphs. Our aim in this study is to test the generality of the assortative colour pairing system, extending our previous analyses to populations with different morph compositions and frequencies. The results show that the assortative pattern of pairing is similar in all the populations analysed and, hence, independent of morph composition and not restricted to pentamorphic populations. This suggests that assortative pairing by colour is a general phenomenon for colour polymorphic populations of P. muralis.

  16. Colour in insect thermoregulation: empirical and theoretical tests in the colour-changing grasshopper, Kosciuscola tristis.

    PubMed

    Umbers, K D L; Herberstein, M E; Madin, J S

    2013-01-01

    Body colours can result in different internal body temperatures, but evidence for the biological significance of colour-induced temperature differences is inconsistent. We investigated the relationship between body colour and temperature in a model insect species that rapidly changes colour. We used an empirical approach and constructed a heat budget model to quantify whether a colour change from black to turquoise has a role in thermoregulation for the chameleon grasshopper (Kosciuscola tristis). Our study shows that colour change in K. tristis provides relatively small temperature differences that vary greatly with wind speed (0.55 °C at ms(-1) to 0.05 °C at 10 ms(-1)). The biological significance of this difference is unclear and we discuss the requirement for more studies that directly test hypotheses regarding the fitness effects of colour in manipulating body temperature.

  17. Colour in insect thermoregulation: empirical and theoretical tests in the colour-changing grasshopper, Kosciuscola tristis.

    PubMed

    Umbers, K D L; Herberstein, M E; Madin, J S

    2013-01-01

    Body colours can result in different internal body temperatures, but evidence for the biological significance of colour-induced temperature differences is inconsistent. We investigated the relationship between body colour and temperature in a model insect species that rapidly changes colour. We used an empirical approach and constructed a heat budget model to quantify whether a colour change from black to turquoise has a role in thermoregulation for the chameleon grasshopper (Kosciuscola tristis). Our study shows that colour change in K. tristis provides relatively small temperature differences that vary greatly with wind speed (0.55 °C at ms(-1) to 0.05 °C at 10 ms(-1)). The biological significance of this difference is unclear and we discuss the requirement for more studies that directly test hypotheses regarding the fitness effects of colour in manipulating body temperature. PMID:23108152

  18. "Close" Encounters...of a Totally Different Kind.

    ERIC Educational Resources Information Center

    Greenman, Geri

    2001-01-01

    Presents a project used in an advanced art class in which students focus on the work of Chuck Close by creating large self-portraits in the manner of Close. Describes the work of different students, such as how one student made a portrait using different colors of Skittles candy. (CMK)

  19. Colour-colour diagrams and extragalactic globular cluster ages. Systematic uncertainties using the (V - K) - (V - I) diagram

    NASA Astrophysics Data System (ADS)

    Salaris, M.; Cassisi, S.

    2007-01-01

    Context: Age and metallicity estimates for extragalactic globular clusters, from integrated colour-colour diagrams, are examined. Aims: We investigate biases in cluster ages and [Fe/H] estimated from the (V-K)-(V-I) diagram, arising from inconsistent Horizontal Branch morphology, metal mixture, treatment of core convection between observed clusters and the theoretical colour grid employed for age and metallicity determinations. We also study the role played by statistical fluctuations of the observed colours, caused by the low total mass of typical globulars. Methods: Synthetic samples of globular cluster systems are created, by means of Monte-Carlo techniques. Each sample accounts for a different possible source of bias, among the ones addressed in this investigation. Cumulative age and [Fe/H] distributions are then retrieved by comparisons with a reference theoretical colour-colour grid, and analyzed. Results: Horizontal Branch morphology is potentially the largest source of uncertainty. A single-age system harbouring a large fraction of clusters with an HB morphology systematically bluer than the one accounted for in the theoretical colour grid, can simulate a bimodal population with an age difference as large as ~8 Gyr. When only the redder clusters are considered, this uncertainty is almost negligible, unless there is an extreme mass loss along the Red Giant Branch phase. The metal mixture affects mainly the redder clusters; the effect of colour fluctuations becomes negligible for the redder clusters, or when the integrated MV is brighter than ~-8.5 mag. The treatment of core convection is relevant for ages below ~4 Gyr. The retrieved cumulative [Fe/H] distributions are overall only mildly affected. Colour fluctuations and convective core extension have the largest effect. When 1σ photometric errors reach 0.10 mag, all biases found in our analysis are erased, and bimodal age populations with age differences of up to ~8 Gyr go undetected. The use of both (U

  20. Human local and total heat losses in different temperature.

    PubMed

    Wang, Lijuan; Yin, Hui; Di, Yuhui; Liu, Yanfeng; Liu, Jiaping

    2016-04-01

    This study investigates the effects of operative temperature on the local and total heat losses, and the relationship between the heat loss and thermal sensation. 10 local parts of head, neck, chest, abdomen, upper arm, forearm, hand, thigh, leg and foot are selected. In all these parts, convection, radiation, evaporation, respiration, conduction and diffusion heat losses are analyzed when operative temperature is 23, 28, 33 and 37 °C. The local heat losses show that the radiation and convection heat losses are mainly affected by the area of local body, and the heat loss of the thigh is the most in the ten parts. The evaporation heat loss is mainly affected by the distribution of sweat gland, and the heat loss of the chest is the most. The total heat loss of the local body shows that in low temperature, the thigh, leg and chest have much heat loss, while in high temperature, the chest, abdomen, thigh and head have great heat loss, which are useful for clothing design. The heat losses of the whole body show that as the operative temperature increases, the radiation and convection heat losses decrease, the heat losses of conduction, respiration, and diffusion are almost constant, and the evaporation heat loss increases. By comparison, the heat loss ratios of the radiation, convection and sweat evaporation, are in agreement with the previous researches. At last, the formula about the heat loss ratio of convection and radiation is derived. It's useful for thermal comfort evaluation and HVAC (heating, ventilation and air conditioning) design. PMID:26879106

  1. Measurement and prediction of pork colour.

    PubMed

    Van Oeckel, M J; Warnants, N; Boucqué, C V

    1999-08-01

    The extent to which instrumental colour determinations by FOPu (light scattering), Göfo (reflectance) and Labscan II (CIE L*, CIE a* and CIE b*, hue and chroma) are related to the Japanese colour grades was studied. Additionally, four on-line methods: pH1, FOP1, PQM1 (conductivity) and DDLT (Double Density Light Transmission, analogous to Capteur Gras/Maigre), were evaluated for their ability to predict subjectively and objectively colour. One hundred and twenty samples of m. longissimus thoracis et lumborum, from animals of different genotypes, were analysed. Of the instrumental colour determinations, CIE L* (r=-0.82), FOPu (r=-0.70) and Göfo (r=0.70) were best correlated with the Japanese colour scores. The Japanese colour grades could be predicted by the on-line instruments, pH1, FOP1, PQM1 and DDLT, with determination coefficients between 15 and 28%. Ultimate meat colour, determined by Japanese colour standards, FOPu, Göfo and CIE L*, was better predicted by DDLT than by the classic on-line instruments: FOP1, pH1 and PQM1, although the standard error of the estimate was similar for all instruments. This means that DDLT, although originally designed for estimating lean meat percentage, can additionally give information about meat quality, in particular colour. However, it must be stressed that the colour estimate by DDLT refers to a population of animals, rather than to individual pigs, because of the number of erroneously assigned samples.

  2. Comparison of Urinary Total Proteins by Four Different Methods.

    PubMed

    Yalamati, Padma; Karra, Madhu Latha; Bhongir, Aparna V

    2016-10-01

    The total proteins in human urine have been compared by sulfosalicylic acid, sulfosalicylic acid with sodium sulphate and trichloroacetic acid methods with pyrogallol red molybdate method as there are no studies found quantifying imprecision and bias components. Fresh urine of 36 patients was analyzed by four methods. Imprecision and inaccuracy were determined by repeated analysis and method comparison studies using correlation plots, Bland and Altman, and Passing and Bablok regression analyses respectively. The coefficient of variation was 5.07 % for pyrogallol red molybdate; 6.84 % for sulfosalicylic acid; 3.97 % for sulfosalicylic acid with sodium sulphate and 5.93 % for trichloroacetic acid methods. Bland and Altman analysis showed a bias of 5.8, 1.7 and -5.4 for pyrogallol red molybdate versus sulfosalicylic acid, sulfosalicylic acid with sodium sulphate and trichloroacetic acid methods respectively. Passing and Bablok regression revealed a constant bias for pyrogallol red molybdate versus all turbidimetric methods but a proportional bias only with trichloroacetic acid method. Sulfosalicylic acid with sodium sulphate method is preferred to sulfosalicylic acid and trichloroacetic acid methods. PMID:27605745

  3. Hemispherical total emissivity of Hastelloy N with different surface conditions

    NASA Astrophysics Data System (ADS)

    Gordon, Andrew J.; Walton, Kyle L.; Ghosh, Tushar K.; Loyalka, Sudarshan K.; Viswanath, Dabir S.; Tompson, Robert V.

    2012-07-01

    The hemispherical total emissivity of Hastelloy N (a candidate structural material for Next Generation Nuclear Plants (NGNPs), particularly for the molten fluoride cooled reactors) was measured using an experimental set-up that was constructed in accordance with the standard ASTM C835-06. The material surface conditions included: (i) 'as received' (original) sample from the supplier; (ii) samples with increased surface roughness through sand blasting; (iii) oxidized surface, and (iv) samples coated with graphite powder. The emissivity of the as received samples varied from around 0.22 to 0.28 in the temperature range of 473 K to 1498 K. The emissivity increased when the roughness of the surface increased compared to an as received sample. When Hastelloy N was oxidized in air at 1153 K or coated with graphite powder, its emissivity increased substantially. The sample sand blasted with 60 grit beads and sprinkled with graphite powder showed an increase of emissivity from 0.2 to 0.60 at 473 K and from 0.25 to 0.67 at 1473 K. The oxidized surface showed a similar behavior: an increase in emissivity compared to an unoxidized sample. This increase in emissivity has strong favorable safety implications in terms of decay heat removal in post-accident environments. The data were compared with another Hastelloy family member, Hastelloy X.

  4. Processing strawberries to different products alters contents of vitamin C, total phenolics, total anthocyanins, and antioxidant capacity.

    PubMed

    Klopotek, Yvonne; Otto, Konrad; Böhm, Volker

    2005-07-13

    Strawberries were processed to juice, nectar, wine, and puree. For investigation of the antioxidant capacity as well as the contents of ascorbic acid, total phenolics and total anthocyanins, samples were taken after different stages of production to determine the effects of processing. The content of vitamin C was measured spectrophotometrically. The total phenolic content was analyzed by using the Folin-Ciocalteu method, and the amount of total anthocyanins was determined by using the pH-differential method. Two different methods-the trolox equivalent antioxidant capacity assay and the ferric reducing antioxidant power test-were used to determine the hydrophilic antioxidant capacity. This study showed the decrease of all investigated parameters within processing strawberries to different products. The content of ascorbic acid decreased with production time and processing steps, especially during heat treatment. The investigations on total phenolics in strawberry products proved fining to be a mild method to clarify berry juices and wines without removing high amounts of total phenolics. Fermentation did not lead to heavy losses of total phenolics, probably due to polymerization and condensation of monomer phenolics such as anthocyanins. Total anthocyanins and the hydrophilic antioxidant capacity decreased while using high temperatures. Anthocyanins also decreased considerably during the processing of wines, mainly caused by fermentation and pasteurization.

  5. Processing strawberries to different products alters contents of vitamin C, total phenolics, total anthocyanins, and antioxidant capacity.

    PubMed

    Klopotek, Yvonne; Otto, Konrad; Böhm, Volker

    2005-07-13

    Strawberries were processed to juice, nectar, wine, and puree. For investigation of the antioxidant capacity as well as the contents of ascorbic acid, total phenolics and total anthocyanins, samples were taken after different stages of production to determine the effects of processing. The content of vitamin C was measured spectrophotometrically. The total phenolic content was analyzed by using the Folin-Ciocalteu method, and the amount of total anthocyanins was determined by using the pH-differential method. Two different methods-the trolox equivalent antioxidant capacity assay and the ferric reducing antioxidant power test-were used to determine the hydrophilic antioxidant capacity. This study showed the decrease of all investigated parameters within processing strawberries to different products. The content of ascorbic acid decreased with production time and processing steps, especially during heat treatment. The investigations on total phenolics in strawberry products proved fining to be a mild method to clarify berry juices and wines without removing high amounts of total phenolics. Fermentation did not lead to heavy losses of total phenolics, probably due to polymerization and condensation of monomer phenolics such as anthocyanins. Total anthocyanins and the hydrophilic antioxidant capacity decreased while using high temperatures. Anthocyanins also decreased considerably during the processing of wines, mainly caused by fermentation and pasteurization. PMID:15998127

  6. 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…

  7. Rehabilitation of a Total Maxillectomy Patient by Three Different Methods

    PubMed Central

    Ramesh; Kumar, C.Dinesh; Sharma, Neeraj; S, Yogesh

    2014-01-01

    Rehabilitation of a patient with orbital defect is highly a challenging task, requiring an individualized design of the technique for each patient. The disfigurement associated with the loss of facial structures causes significant emotional stress and physical burdens.Various treatment modalities are available, one of which is the use of implants. Although implant-supported orbital prosthesis has a superior outcome, it may not be advisable in all the patients due to economic factors. The treatment of choice includes the silicone orbital prosthesis due to its life-like appearance. This article describes three different techniques, it’s advantages and limitations of fabricating a silicone orbital prosthesis for the same patient to achieve ideal fit and aesthetics. PMID:25478462

  8. The determination of total burn surface area: How much difference?

    PubMed

    Giretzlehner, M; Dirnberger, J; Owen, R; Haller, H L; Lumenta, D B; Kamolz, L-P

    2013-09-01

    Burn depth and burn size are crucial determinants for assessing patients suffering from burns. Therefore, a correct evaluation of these factors is optimal for adapting the appropriate treatment in modern burn care. Burn surface assessment is subject to considerable differences among clinicians. This work investigated the accuracy among experts based on conventional surface estimation methods (e.g. "Rule of Palm", "Rule of Nines" or "Lund-Browder Chart"). The estimation results were compared to a computer-based evaluation method. Survey data was collected during one national and one international burn conference. The poll confirmed deviations of burn depth/size estimates of up to 62% in relation to the mean value of all participants. In comparison to the computer-based method, overestimation of up to 161% was found. We suggest introducing improved methods for burn depth/size assessment in clinical routine in order to efficiently allocate and distribute the available resources for practicing burn care.

  9. Colour and carotenoid changes of pasteurised orange juice during storage.

    PubMed

    Wibowo, Scheling; Vervoort, Liesbeth; Tomic, Jovana; Santiago, Jihan Santanina; Lemmens, Lien; Panozzo, Agnese; Grauwet, Tara; Hendrickx, Marc; Van Loey, Ann

    2015-03-15

    The correlation of carotenoid changes with colour degradation of pasteurised single strength orange juice was investigated at 20, 28, 35 and 42°C for a total of 32 weeks of storage. Changes in colour were assessed using the CIELAB system and were kinetically described by a zero-order model. L(∗), a(∗), b(∗), ΔE(∗), Cab(∗) and hab were significantly changed during storage (p<0.05). Activation energies for all colour parameters were 64-73 kJ mol(-1). Several carotenoids showed important changes and appeared to have different susceptibilities to storage. A decrease of β-cryptoxanthin was observed at higher temperatures, whereas antheraxanthin started to decrease at lower temperatures. Depending on the time and temperature, changes in carotenoids could be due to isomerisation reactions, which may lead to a perceptible colour change. Although the contribution of carotenoids was recognised to some extent, other reactions seem of major importance for colour degradation of orange juice during storage.

  10. A vector model of colour contrast in a cone-excitation colour space.

    PubMed

    Shepherd, A J

    1997-01-01

    A vector model of colour contrast is examined in a colour space that is a logarithmic transformation of the MacLeod-Boynton cone-excitation diagram. Observers set matches in a haploscopic display, in which one eye viewed a standard display (a neutral target square in a coloured surround) and the other viewed a matching display (a variable square in its own surround). Contrast colours are simply represented in this colour space: the vector connecting the right-eye surround and matched chromaticities is parallel to and to the same length and direction as the vector that connects the left-eye (standard) surround and square chromaticities. This describes observers' matches to the hues induced in a neutral square for a range of inducing surround colours, a range of right-eye (match) surround colours and four different luminance contrasts.

  11. Prevalence of colour blindness in young Jordanians.

    PubMed

    Al-Aqtum, M T; Al-Qawasmeh, M H

    2001-01-01

    Colour blindness is one of the common genetic disorders observed in all human populations. It is a sex-linked recessive trait. The genes are located on the X chromosome within the Xq28 band. 1,418 university students (1,200 female and 218 male) from Zarka Private University and the Hashemite University were randomly selected and tested for congenital red/green colour blindness, by using Ishihara pseudo-isochromatic colour plates. A total of 23 individuals were found to be colour blind. In females, 4 students (0.33%) were colour blind: 1 of them showed protanomalia, 1 protanopia and 2 deuteranomalia. In males, 19 students (8.72%) were colour blind: 4 showed protanomalia, 3 protanopia, 8 deuteranomalia and 4 deuteranopia. The allelic frequencies of the colour vision gene were found to be 0.087 in males, 0.003 in females and 0.016 in the total population. Studies on colour blindness in Jordan are very few; this population-based investigation is meant to fill a gap in this field.

  12. Colour Vision Impairment in Young Alcohol Consumers.

    PubMed

    Brasil, Alódia; Castro, Antônio José O; Martins, Isabelle Christine V S; Lacerda, Eliza Maria C B; Souza, Givago S; Herculano, Anderson Manoel; Rosa, Alexandre Antônio M; Rodrigues, Anderson R; Silveira, Luiz Carlos L

    2015-01-01

    Alcohol consumption among young adults is widely accepted in modern society and may be the starting point for abusive use of alcohol at later stages of life. Chronic alcohol exposure can lead to visual function impairment. In the present study, we investigated the spatial luminance contrast sensitivity, colour arrangement ability, and colour discrimination thresholds on young adults that weekly consume alcoholic beverages without clinical concerns. Twenty-four young adults were evaluated by an ophthalmologist and performed three psychophysical tests to evaluate their vision functions. We estimated the spatial luminance contrast sensitivity function at 11 spatial frequencies ranging from 0.1 to 30 cycles/degree. No difference in contrast sensitivity was observed comparing alcohol consumers and control subjects. For the evaluation of colour vision, we used the Farnsworth-Munsell 100 hue test (FM 100 test) to test subject's ability to perform a colour arrangement task and the Mollon-Reffin test (MR test) to measure subject's colour discrimination thresholds. Alcohol consumers made more mistakes than controls in the FM100 test, and their mistakes were diffusely distributed in the FM colour space without any colour axis preference. Alcohol consumers also performed worse than controls in the MR test and had higher colour discrimination thresholds compared to controls around three different reference points of a perceptually homogeneous colour space, the CIE 1976 chromaticity diagram. There was no colour axis preference in the threshold elevation observed among alcoholic subjects. Young adult weekly alcohol consumers showed subclinical colour vision losses with preservation of spatial luminance contrast sensitivity. Adolescence and young adult age are periods of important neurological development and alcohol exposure during this period of life might be responsible for deficits in visual functions, especially colour vision that is very sensitive to neurotoxicants. PMID

  13. Colour Vision Impairment in Young Alcohol Consumers.

    PubMed

    Brasil, Alódia; Castro, Antônio José O; Martins, Isabelle Christine V S; Lacerda, Eliza Maria C B; Souza, Givago S; Herculano, Anderson Manoel; Rosa, Alexandre Antônio M; Rodrigues, Anderson R; Silveira, Luiz Carlos L

    2015-01-01

    Alcohol consumption among young adults is widely accepted in modern society and may be the starting point for abusive use of alcohol at later stages of life. Chronic alcohol exposure can lead to visual function impairment. In the present study, we investigated the spatial luminance contrast sensitivity, colour arrangement ability, and colour discrimination thresholds on young adults that weekly consume alcoholic beverages without clinical concerns. Twenty-four young adults were evaluated by an ophthalmologist and performed three psychophysical tests to evaluate their vision functions. We estimated the spatial luminance contrast sensitivity function at 11 spatial frequencies ranging from 0.1 to 30 cycles/degree. No difference in contrast sensitivity was observed comparing alcohol consumers and control subjects. For the evaluation of colour vision, we used the Farnsworth-Munsell 100 hue test (FM 100 test) to test subject's ability to perform a colour arrangement task and the Mollon-Reffin test (MR test) to measure subject's colour discrimination thresholds. Alcohol consumers made more mistakes than controls in the FM100 test, and their mistakes were diffusely distributed in the FM colour space without any colour axis preference. Alcohol consumers also performed worse than controls in the MR test and had higher colour discrimination thresholds compared to controls around three different reference points of a perceptually homogeneous colour space, the CIE 1976 chromaticity diagram. There was no colour axis preference in the threshold elevation observed among alcoholic subjects. Young adult weekly alcohol consumers showed subclinical colour vision losses with preservation of spatial luminance contrast sensitivity. Adolescence and young adult age are periods of important neurological development and alcohol exposure during this period of life might be responsible for deficits in visual functions, especially colour vision that is very sensitive to neurotoxicants.

  14. Colour Vision Impairment in Young Alcohol Consumers

    PubMed Central

    Brasil, Alódia; Castro, Antônio José O.; Martins, Isabelle Christine V. S.; Lacerda, Eliza Maria C. B.; Souza, Givago S.; Herculano, Anderson Manoel; Rosa, Alexandre Antônio M.; Rodrigues, Anderson R.; Silveira, Luiz Carlos L.

    2015-01-01

    Alcohol consumption among young adults is widely accepted in modern society and may be the starting point for abusive use of alcohol at later stages of life. Chronic alcohol exposure can lead to visual function impairment. In the present study, we investigated the spatial luminance contrast sensitivity, colour arrangement ability, and colour discrimination thresholds on young adults that weekly consume alcoholic beverages without clinical concerns. Twenty-four young adults were evaluated by an ophthalmologist and performed three psychophysical tests to evaluate their vision functions. We estimated the spatial luminance contrast sensitivity function at 11 spatial frequencies ranging from 0.1 to 30 cycles/degree. No difference in contrast sensitivity was observed comparing alcohol consumers and control subjects. For the evaluation of colour vision, we used the Farnsworth-Munsell 100 hue test (FM 100 test) to test subject’s ability to perform a colour arrangement task and the Mollon-Reffin test (MR test) to measure subject’s colour discrimination thresholds. Alcohol consumers made more mistakes than controls in the FM100 test, and their mistakes were diffusely distributed in the FM colour space without any colour axis preference. Alcohol consumers also performed worse than controls in the MR test and had higher colour discrimination thresholds compared to controls around three different reference points of a perceptually homogeneous colour space, the CIE 1976 chromaticity diagram. There was no colour axis preference in the threshold elevation observed among alcoholic subjects. Young adult weekly alcohol consumers showed subclinical colour vision losses with preservation of spatial luminance contrast sensitivity. Adolescence and young adult age are periods of important neurological development and alcohol exposure during this period of life might be responsible for deficits in visual functions, especially colour vision that is very sensitive to neurotoxicants. PMID

  15. Practical colour management

    NASA Astrophysics Data System (ADS)

    Williams, Susan

    2006-06-01

    Spectrophotometers have been successfully used for colour measurement. This paper addresses digital imaging as a complementary and alternative method of colour measurement and appearance and an effective communication tool as part of a practical colour management programme within the supply chain of a textile retailer. The specific needs—to measure and communicate textured dyed material and printed fabric—are discussed, as well as the colour specification and quality control (QC) of currently un-measurable fabrics and accessories. A unique method of using digital imaging for the assessment of colour fastness will also be discussed.

  16. Colour thresholds in a coral reef fish

    PubMed Central

    Vorobyev, M.; Marshall, N. J.

    2016-01-01

    Coral reef fishes are among the most colourful animals in the world. Given the diversity of lifestyles and habitats on the reef, it is probable that in many instances coloration is a compromise between crypsis and communication. However, human observation of this coloration is biased by our primate visual system. Most animals have visual systems that are ‘tuned’ differently to humans; optimized for different parts of the visible spectrum. To understand reef fish colours, we need to reconstruct the appearance of colourful patterns and backgrounds as they are seen through the eyes of fish. Here, the coral reef associated triggerfish, Rhinecanthus aculeatus, was tested behaviourally to determine the limits of its colour vision. This is the first demonstration of behavioural colour discrimination thresholds in a coral reef species and is a critical step in our understanding of communication and speciation in this vibrant colourful habitat. Fish were trained to discriminate between a reward colour stimulus and series of non-reward colour stimuli and the discrimination thresholds were found to correspond well with predictions based on the receptor noise limited visual model and anatomy of the eye. Colour discrimination abilities of both reef fish and a variety of animals can therefore now be predicted using the parameters described here. PMID:27703704

  17. Effects of soaking, boiling and autoclaving on the phenolic contents and antioxidant activities of faba beans (Vicia faba L.) differing in seed coat colours.

    PubMed

    Siah, Siem; Wood, Jennifer A; Agboola, Samson; Konczak, Izabela; Blanchard, Christopher L

    2014-01-01

    The Australian grown faba beans of different seed coat colours were either soaked, boiled or autoclaved, and analysed for phenolic contents and antioxidant activity using an array of reagent-based assays. Soaking, boiling and autoclaving were shown to lower the level of active compounds in faba beans. A significant amount of active compounds was leached to the soaking and cooking medium. Boiling was a better method in retaining active compounds in beans than autoclaving. The boiled beans had more active compounds than those of resulting cooking broths, which was the opposite observation when autoclaving. The buff-genotypes had a similar level of active compounds to red- and green-genotypes. The high performance liquid chromatography-post column derivatisation (HPLC-PCD) system detected a dense collection of high antioxidant HPLC peaks ('humps') in extracts of raw, soaked and boiled beans. The present findings encouraged consumption of faba beans together with cooking broth for the maximum potential health benefits.

  18. 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.

  19. Colour vision experimental studies in teaching of optometry

    NASA Astrophysics Data System (ADS)

    Ozolinsh, Maris; Ikaunieks, Gatis; Fomins, Sergejs

    2005-10-01

    Following aspects related to human colour vision are included in experimental lessons for optometry students of University of Latvia. Characteristics of coloured stimuli (emitting and reflective), determination their coordinates in different colour spaces. Objective characteristics of transmitting of colour stimuli through the optical system of eye together with various types of appliances (lenses, prisms, Fresnel prisms). Psychophysical determination of mono- and polychromatic stimuli perception taking into account physiology of eye, retinal colour photoreceptor topography and spectral sensitivity, spatial and temporal characteristics of retinal receptive fields. Ergonomics of visual perception, influence of illumination and glare effects, testing of colour vision deficiencies.

  20. Colour Mathematics: With Graphs and Numbers

    ERIC Educational Resources Information Center

    LoPresto, Michael C.

    2009-01-01

    The different combinations involved in additive and subtractive colour mixing can often be difficult for students to remember. Using transmission graphs for filters of the primary colours and a numerical scheme to write out the relationships are good exercises in analytical thinking that can help students recall the combinations rather than just…

  1. Colour Vision: Understanding #TheDress.

    PubMed

    Brainard, David H; Hurlbert, Anya C

    2015-06-29

    A widely-viewed image of a dress elicits striking individual variation in colour perception. Experiments with multiple variants of the image suggest that the individual differences may arise through the action of visual mechanisms that normally stabilise object colour. PMID:26126278

  2. Colour mathematics: with graphs and numbers

    NASA Astrophysics Data System (ADS)

    Lo Presto, Michael C.

    2009-07-01

    The different combinations involved in additive and subtractive colour mixing can often be difficult for students to remember. Using transmission graphs for filters of the primary colours and a numerical scheme to write out the relationships are good exercises in analytical thinking that can help students recall the combinations rather than just attempting to memorize them.

  3. The Colour of the Young Universe

    NASA Astrophysics Data System (ADS)

    2003-12-01

    VLT study gives insight on the evolution of the star formation rate Summary An international team of astronomers [1] has determined the colour of the Universe when it was very young. While the Universe is now kind of beige, it was much bluer in the distant past , at a time when it was only 2,500 million years old. This is the outcome of an extensive and thorough analysis of more than 300 galaxies seen within a small southern sky area, the so-called Hubble Deep Field South. The main goal of this advanced study was to understand how the stellar content of the Universe was assembled and has changed over time. Dutch astronomer Marijn Franx , a team member from the Leiden Observatory (The Netherlands), explains: "The blue colour of the early Universe is caused by the predominantly blue light from young stars in the galaxies. The redder colour of the Universe today is caused by the relatively larger number of older, redder stars." The team leader, Gregory Rudnick from the Max-Planck Institut für Astrophysics (Garching, Germany) adds: "Since the total amount of light in the Universe in the past was about the same as today and a young blue star emits much more light than an old red star, there must have been significantly fewer stars in the young Universe than there is now. Our new findings imply that the majority of stars in the Universe were formed comparatively late, not so long before our Sun was born, at a moment when the Universe was around 7,000 million years old." These new results are based on unique data collected during more than 100 hours of observations with the ISAAC multi-mode instrument at ESO's Very Large Telescope (VLT), as part of a major research project, the Faint InfraRed Extragalactic Survey (FIRES) . The distances to the galaxies were estimated from their brightness in different optical near-infrared wavelength bands. PR Photo 34/03 : The Evolving Colour of the Universe . Observing the early Universe It is now well known that the Sun was formed

  4. Colour constancy in insects.

    PubMed

    Chittka, Lars; Faruq, Samia; Skorupski, Peter; Werner, Annette

    2014-06-01

    Colour constancy is the perceptual phenomenon that the colour of an object appears largely unchanged, even if the spectral composition of the illuminating light changes. Colour constancy has been found in all insect species so far tested. Especially the pollinating insects offer a remarkable opportunity to study the ecological significance of colour constancy since they spend much of their adult lives identifying and choosing between colour targets (flowers) under continuously changing ambient lighting conditions. In bees, whose colour vision is best studied among the insects, the compensation provided by colour constancy is only partial and its efficiency depends on the area of colour space. There is no evidence for complete 'discounting' of the illuminant in bees, and the spectral composition of the light can itself be used as adaptive information. In patchy illumination, bees adjust their spatial foraging to minimise transitions between variously illuminated zones. Modelling allows the quantification of the adaptive benefits of various colour constancy mechanisms in the economy of nature. We also discuss the neural mechanisms and cognitive operations that might underpin colour constancy in insects.

  5. Occupational colour vision requirements for police officers.

    PubMed

    Birch, Jennifer; Chisholm, Catharine M

    2008-11-01

    Inclusion of public service professions in the UK Disability Discrimination Act in 2004 prompted a review of occupational colour vision requirements for police officers. Changes in the regulations which existed prior to 2003 were proposed. The aim of this study was to obtain the views of serving police officers in Northern Ireland on the importance of good colour discrimination in everyday police work and on the recruitment regulations for patrol constables introduced in 2003 in mainland UK. These views were obtained by means of a questionnaire and informal discussions. More than 65% of police officers who responded to the questionnaire considered that good colour vision was very important for effective policing. Fewer than 2% considered that colour vision was unimportant. Experienced police officers agreed that the employment of colour-deficient patrol constables, as permitted in the new regulations, would lead to reduced efficiency and organisational difficulties at the local level. A number of everyday activities were described which showed the need for accurate colour discrimination. The change in recruitment policy and the lack of clarity in the new regulations show inadequate appreciation of the needs of the occupation, of different types of colour vision anomalies and of the diagnostic function of colour vision tests. Failure to provide guidance on appropriate colour vision tests, examination procedures and counselling services is likely to result in inconsistent employment policies in different police forces. It is recommended that the colour vision standard in place prior to 2003 is reinstated at the recruitment stage. The Ishihara test should be used for screening, and colour-deficient applicants further examined with the Farnsworth D15 test as a replacement for the City University Test 2nd edition. PMID:19076554

  6. 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.

  7. An investigation into the genetic background of coat colour dilution in a Charolais x German Holstein F2 resource population.

    PubMed

    Kühn, Ch; Weikard, R

    2007-04-01

    The molecular background of many loci affecting coat colour inheritance in cattle is still incompletely characterized, although it is known that coat colour results from the joint effects of several loci, e.g. agouti, extension and dilution. Dilution alleles are responsible for a dilution effect on the original coat colour of an individual, which is determined by the agouti and extension loci. Different loci affecting dilution of pigment are suggested in Charolais (Dc) and Simmental (Ds). To enable chromosomal mapping of the Dc mutation, 133 animals from an F2 full-sib resource population generated from a cross of Charolais and German Holstein were scored for the coat colour dilution phenotype. Linkage analysis covering all autosomes revealed a significant linkage of the dilution phenotype with microsatellite markers on bovine chromosome 5. No recombination was observed between marker ETH10 and the Dc locus. Positional and functional information identified the bovine silver homolog (SILV) gene as a candidate for the Dc mutation. Results from comparative sequencing of the SILV gene in individuals with different dilution coat colour phenotypes confirmed the presence of a c.64G>A non-synonymous mutation, which had previously been identified in the Charolais breed. The alleles at this locus were associated with coat colour dilution in this study. However, further investigation of colour inheritance within the F2 resource population indicated that a single diallelic mutation in the SILV gene cannot explain the total observed variation of coat colour dilution.

  8. Silorane, ormocer, methacrylate and compomer long-term staining susceptibility using ΔE and ΔE 00 colour-difference formulas.

    PubMed

    Gregor, Ladislav; Krejci, Ivo; Di Bella, Enrico; Feilzer, Albert J; Ardu, Stefano

    2016-09-01

    The aim of this study was to evaluate the staining susceptibility of a silorane (Filtek Silorane), an ormocer (Ceram X Duo), a methacrylate (Tetric EvoCeram) and a compomer (Dyract) exposed on the long term to various staining agents by using ΔE and ΔE 00 colour-difference formulas. Thirty-six disc-shaped specimens were made of each of the four chemically different materials, randomly divided in six groups (n = 6) and immersed in five staining solutions (red wine, juice, coke, tea and coffee) or stored dry (control) in an incubator at 37 °C for 99 days. Spectrophotometric measurements by means of a spectrophotometer (Spectroshade Handy Dental, MHT) were repeated over a white (L* = 92.6, a* = -1.2, b* = 2.9) and black (L* = 1.6, a* = 1.2, b* = -1.0) background made of plasticized paper, in order to determine the colour changes according to ΔE, ΔE 00 and translucency formulas. Statistical analysis was performed by means of factorial Anova, Fisher's LSD test (post hoc) and a Spearman rank correlation between ΔE and ΔE 00. When analysed over a white background, mean ΔE 00 values were highly significantly different and varied from 0.8 (Ceram X Duo/air) to 20.9 (Ceram X Duo/red wine). When analysed over a black background, mean ΔE 00 values were highly significantly different and varied from 1.0 (Ceram X Duo and Tetric/air) to 25.2 (Ceram X Duo/red wine). Differences in translucency varied from 0.3 (Ceram X Duo/air) to 21.1 (Ceram X Duo/juice). The correlation between ΔE and ΔE 00 over a white background was 0.9928, while over a black background, it was 0.9886. PMID:26178651

  9. Colour is more than hue: preferences for compiled colour traits in the stingless bees Melipona mondury and M. quadrifasciata.

    PubMed

    Koethe, Sebastian; Bossems, Jessica; Dyer, Adrian G; Lunau, Klaus

    2016-10-01

    The colour vision of bees has been extensively analysed in honeybees and bumblebees, but few studies consider the visual perception of stingless bees (Meliponini). In a five-stage experiment the preference for colour intensity and purity, and the preference for the dominant wavelength were tested by presenting four colour stimuli in each test to freely flying experienced workers of two stingless bee species, Melipona mondury and Melipona quadrifasciata. The results with bee-blue, bee-UV-blue and bee-green colours offered in four combinations of varying colour intensity and purity suggest a complex interaction between these colour traits for the determination of colour choice. Specifically, M. mondury preferred bee-UV-blue colours over bee-green, bee-blue and bee-blue-green colours while M. quadrifasciata preferred bee-green colour stimuli. Moreover in M. mondury the preferences were different if the background colour was changed from grey to green. There was a significant difference between species where M. mondury preferred UV-reflecting over UV-absorbing bee-blue-green colour stimuli, whereas M. quadrifasciata showed an opposite preference. The different colour preferences of the free flying bees in identical conditions may be caused by the bees' experience with natural flowers precedent to the choice tests, suggesting reward partitioning between species. PMID:27480640

  10. Colour is more than hue: preferences for compiled colour traits in the stingless bees Melipona mondury and M. quadrifasciata.

    PubMed

    Koethe, Sebastian; Bossems, Jessica; Dyer, Adrian G; Lunau, Klaus

    2016-10-01

    The colour vision of bees has been extensively analysed in honeybees and bumblebees, but few studies consider the visual perception of stingless bees (Meliponini). In a five-stage experiment the preference for colour intensity and purity, and the preference for the dominant wavelength were tested by presenting four colour stimuli in each test to freely flying experienced workers of two stingless bee species, Melipona mondury and Melipona quadrifasciata. The results with bee-blue, bee-UV-blue and bee-green colours offered in four combinations of varying colour intensity and purity suggest a complex interaction between these colour traits for the determination of colour choice. Specifically, M. mondury preferred bee-UV-blue colours over bee-green, bee-blue and bee-blue-green colours while M. quadrifasciata preferred bee-green colour stimuli. Moreover in M. mondury the preferences were different if the background colour was changed from grey to green. There was a significant difference between species where M. mondury preferred UV-reflecting over UV-absorbing bee-blue-green colour stimuli, whereas M. quadrifasciata showed an opposite preference. The different colour preferences of the free flying bees in identical conditions may be caused by the bees' experience with natural flowers precedent to the choice tests, suggesting reward partitioning between species.

  11. Colour-grapheme synesthesia affects binocular vision.

    PubMed

    Paffen, Chris L E; van der Smagt, Maarten J; Nijboer, Tanja C W

    2011-01-01

    In colour-grapheme synesthesia, non-coloured graphemes are perceived as being inherently coloured. In recent years, it is debated whether visual processing of synesthesia-inducing achromatic graphemes is similar to that of chromatic graphemes. Here, we exploit the phenomenon of binocular rivalry in which incompatible images presented dichoptically compete for conscious expression. Importantly, the competition only arises if the two images are sufficiently different; if the difference between the images is small, the images will fuse into a single mixed percept. We show that achromatic digits that induce synesthetic colour percepts increase the incidence of binocular rivalry compared to achromatic non-digits that do not evoke such percepts. That is, compared to achromatically perceived non-digits, synesthesia-inducing digits increase the predominance of binocular rivalry over binocular fusion. This finding shows that the synesthetic colour experience can provide the conditions for promoting binocular rivalry, much like stimulus features that induce rivalry in normal vision.

  12. Using students' misconceptions of primary coloured lights to design a hands-on coloured light mixer

    NASA Astrophysics Data System (ADS)

    Nopparatjamjomras, Suchai; Chitaree, Ratchapak

    2009-06-01

    A surface mount typed multi-coloured Light-Emitting Diode (LED) is used as a light source for the hands-on coloured light mixer. The LED consists of red, green and blue tiny sources but the mixer is designed to have four switches corresponding to red, green, blue and yellow light. These colours correspond to students' misconceptions of primary coloured lights; they realize that the primary colours and the rules for lights mixing are the same as those of paints. To generate a yellow light, a microcontroller placed between four input switches and the LED operates both a red and green tiny sources. In addition, the microcontroller is employed to eliminate some combinations of coloured light mixing to simplify the experiment (basic mode) for non advanced students. If the mixer is used with more advanced students, a number of combinations will increase and students need more analytical skills to find out the primary coloured lights (the coloured lights that can not be produced by the mixing of any other coloured lights). Therefore, the mixer is able to use with more advanced and non advanced students depending on the program in the microcontroller and some modifications of the circuit. Furthermore, to introduce students an idea that other hues or shades can be generated by mixing of these three primary coloured lights of different intensities, a tuning circuit is integrated to vary an intensity of the green light source.

  13. Colour preferences influences odour learning in the hawkmoth, Macroglossum stellatarum

    NASA Astrophysics Data System (ADS)

    Balkenius, Anna; Kelber, Almut

    2006-05-01

    The hummingbird hawkmoth, Macroglossum stellatarum, learns colour fast and reliably. It has earlier been shown to spontaneously feed from odourless artificial flowers. Now, we have studied odour learning. The moths were trained to discriminate feeders of the same colour but marked with different odours. They did not learn to discriminate two natural flower odours when they were presented with the innately preferred colour blue, but they did learn this discrimination combined with yellow or green colours that are less attractive to the moth. The yellow colour could be trained to become as attractive as the innately preferred blue colour and the blue colour could be trained to become less attractive. This is the first proof of odour learning in a diurnal moth. The results show that M. stellatarum can use more than one modality in their foraging behaviour and that the system is plastic. By manipulating the preferences for the different colours, their influence on odour learning could be changed.

  14. 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.

  15. Structural colour in Chondrus crispus.

    PubMed

    Chandler, Chris J; Wilts, Bodo D; Vignolini, Silvia; Brodie, Juliet; Steiner, Ullrich; Rudall, Paula J; Glover, Beverley J; Gregory, Thomas; Walker, Rachel H

    2015-01-01

    The marine world is incredibly rich in brilliant and intense colours. Photonic structures are found in many different species and provide extremely complex optical responses that cannot be achieved solely by pigments. In this study we examine the cuticular structure of the red alga Chondrus crispus (Irish Moss) using anatomical and optical approaches. We experimentally measure the optical response of the multilayer structure in the cuticle. Using finite-difference time-domain modelling, we demonstrate conclusively for the first time that the dimensions and organisation of lamellae are responsible for the blue structural colouration on the surface of the fronds. Comparison of material along the apical-basal axis of the frond demonstrates that structural colour is confined to the tips of the thalli and show definitively that a lack of structural colour elsewhere corresponds with a reduction in the number of lamellae and the regularity of their ordering. Moreover, by studying the optical response for different hydration conditions, we demonstrate that the cuticular structure is highly porous and that the presence of water plays a critical role in its ability to act as a structural light reflector. PMID:26139470

  16. Patellar resurfacing in total knee arthroplasty: functional outcome differs with different outcome scores

    PubMed Central

    Aunan, Eirik; Næss, Grethe; Clarke-Jenssen, John; Sandvik, Leiv; Kibsgård, Thomas Johan

    2016-01-01

    Background and purpose — Recent research on outcomes after total knee arthroplasty (TKA) has raised the question of the ability of traditional outcome measures to distinguish between treatments. We compared functional outcomes in patients undergoing TKA with and without patellar resurfacing, using the knee injury and osteoarthritis outcome score (KOOS) as the primary outcome and 3 traditional outcome measures as secondary outcomes. Patients and methods — 129 knees in 115 patients (mean age 70 (42–82) years; 67 female) were evaluated in this single-center, randomized, double-blind study. Data were recorded preoperatively, at 1 year, and at 3 years, and were assessed using repeated-measures mixed models. Results — The mean subscores for the KOOS after surgery were statistically significantly in favor of patellar resurfacing: sport/recreation, knee-related quality of life, pain, and symptoms. No statistically significant differences between the groups were observed with the Knee Society clinical rating system, with the Oxford knee score, and with visual analog scale (VAS) for patient satisfaction. Interpretation — In the present study, the KOOS—but no other outcome measure used—indicated that patellar resurfacing may be beneficial in TKA. PMID:26540368

  17. 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.

  18. Galaxy And Mass Assembly (GAMA): Galaxy colour gradients versus colour, structure, and luminosity

    NASA Astrophysics Data System (ADS)

    Kennedy, Rebecca; Bamford, Steven P.; Häußler, Boris; Brough, Sarah; Holwerda, Benne; Hopkins, Andrew M.; Vika, Marina; Vulcani, Benedetta

    2016-09-01

    Using single-component fits to SDSS/UKIDSS images of galaxies in the G09 region of the GAMA survey we study radial colour gradients across the galaxy population. We use the multi-wavelength information provided by MegaMorph analysis of galaxy light profiles to calculate intrinsic colour gradients, and divide into six subsamples split by overall Sérsic index (n) and galaxy colour. We find a bimodality in the colour gradients of high- and low-n galaxies in all wavebands which varies with overall galaxy luminosity. Global trends in colour gradients therefore result from combining the contrasting behaviour of a number of different galaxy populations. The ubiquity of strong negative colour gradients supports the picture of inside-out growth through gas accretion for blue, low-n galaxies, and through dry minor mergers for red, high-n galaxies. An exception is the blue high-n population which has properties indicative of dissipative major mergers.

  19. Measurement and prediction of pork colour.

    PubMed

    Van Oeckel, M J; Warnants, N; Boucqué, C V

    1999-08-01

    The extent to which instrumental colour determinations by FOPu (light scattering), Göfo (reflectance) and Labscan II (CIE L*, CIE a* and CIE b*, hue and chroma) are related to the Japanese colour grades was studied. Additionally, four on-line methods: pH1, FOP1, PQM1 (conductivity) and DDLT (Double Density Light Transmission, analogous to Capteur Gras/Maigre), were evaluated for their ability to predict subjectively and objectively colour. One hundred and twenty samples of m. longissimus thoracis et lumborum, from animals of different genotypes, were analysed. Of the instrumental colour determinations, CIE L* (r=-0.82), FOPu (r=-0.70) and Göfo (r=0.70) were best correlated with the Japanese colour scores. The Japanese colour grades could be predicted by the on-line instruments, pH1, FOP1, PQM1 and DDLT, with determination coefficients between 15 and 28%. Ultimate meat colour, determined by Japanese colour standards, FOPu, Göfo and CIE L*, was better predicted by DDLT than by the classic on-line instruments: FOP1, pH1 and PQM1, although the standard error of the estimate was similar for all instruments. This means that DDLT, although originally designed for estimating lean meat percentage, can additionally give information about meat quality, in particular colour. However, it must be stressed that the colour estimate by DDLT refers to a population of animals, rather than to individual pigs, because of the number of erroneously assigned samples. PMID:22062695

  20. INVESTIGATION OF RESPONSE DIFFERENCES BETWEEN DIFFERENT TYPES OF TOTAL ORGANIC CARBON (TOC) ANALYTICAL INSTRUMENT SYSTEMS

    EPA Science Inventory

    Total organic carbon (TOC) and dissolved organic carbon (DOC) have long been used to estimate the amount of natural organic matter (NOM) found in raw and finished drinking water. In recent years, computer automation and improved instrumental analysis technologies have created a ...

  1. Adaptive colouration in amphibians.

    PubMed

    Rudh, Andreas; Qvarnström, Anna

    2013-01-01

    Amphibians, i.e. salamanders, frogs and caecilians show a wide range of bright colours in combination with contrasting patterns. There is variation among species, populations and also within species and populations. Furthermore, individuals often change colours during developmental stages or in response to environmental factors. This extraordinary variation means that there are excellent opportunities to test hypotheses of the adaptive significance of colours using amphibian species as models. We review the present view of functions of colouration in amphibians with the main focus on relatively unexplored topics. Variation in colouration has been found to play a role in thermoregulation, UV protection, predator avoidance and sexual signalling. However, many proposed cases of adaptive functions of colouration in amphibians remain virtually scientifically unexplored and surprisingly few genes influencing pigmentation or patterning have been detected. We would like to especially encourage more studies that take advantage of recent developments in measurement of visual properties of several possible signalling receivers (e.g. predators, competitors or mates). Future investigations on interactions between behaviour, ecology and vision have the potential to challenge our current view of the adaptive function of colouration in amphibians.

  2. Adaptive colouration in amphibians.

    PubMed

    Rudh, Andreas; Qvarnström, Anna

    2013-01-01

    Amphibians, i.e. salamanders, frogs and caecilians show a wide range of bright colours in combination with contrasting patterns. There is variation among species, populations and also within species and populations. Furthermore, individuals often change colours during developmental stages or in response to environmental factors. This extraordinary variation means that there are excellent opportunities to test hypotheses of the adaptive significance of colours using amphibian species as models. We review the present view of functions of colouration in amphibians with the main focus on relatively unexplored topics. Variation in colouration has been found to play a role in thermoregulation, UV protection, predator avoidance and sexual signalling. However, many proposed cases of adaptive functions of colouration in amphibians remain virtually scientifically unexplored and surprisingly few genes influencing pigmentation or patterning have been detected. We would like to especially encourage more studies that take advantage of recent developments in measurement of visual properties of several possible signalling receivers (e.g. predators, competitors or mates). Future investigations on interactions between behaviour, ecology and vision have the potential to challenge our current view of the adaptive function of colouration in amphibians. PMID:23664831

  3. Edges, colour and awareness in blindsight.

    PubMed

    Alexander, Iona; Cowey, Alan

    2010-06-01

    It remains unclear what is being processed in blindsight in response to faces, colours, shapes, and patterns. This was investigated in two hemianopes with chromatic and achromatic stimuli with sharp or shallow luminance or chromatic contrast boundaries or temporal onsets. Performance was excellent only when stimuli had sharp spatial boundaries. When discrimination between isoluminant coloured Gaussians was good it declined to chance levels if stimulus onset was slow. The ability to discriminate between instantaneously presented colours in the hemianopic field depended on their luminance, indicating that wavelength discrimination totally independent of other stimulus qualities is absent. When presented with narrow-band colours the hemianopes detected a stimulus maximally effective for S-cones but invisible to M- and L-cones, indicating that blindsight is mediated not just by the mid-brain, which receives no S-cone input, or that the rods contribute to blindsight. The results show that only simple stimulus features are processed in blindsight.

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

    PubMed Central

    Kelber, Almut; Osorio, Daniel

    2010-01-01

    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. PMID:20164101

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

    PubMed

    Kelber, Almut; Osorio, Daniel

    2010-06-01

    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. PMID:20164101

  6. Object knowledge modulates colour appearance

    PubMed Central

    Witzel, Christoph; Valkova, Hanna; Hansen, Thorsten; Gegenfurtner, Karl R

    2011-01-01

    We investigated the memory colour effect for colour diagnostic artificial objects. Since knowledge about these objects and their colours has been learned in everyday life, these stimuli allow the investigation of the influence of acquired object knowledge on colour appearance. These investigations are relevant for questions about how object and colour information in high-level vision interact as well as for research about the influence of learning and experience on perception in general. In order to identify suitable artificial objects, we developed a reaction time paradigm that measures (subjective) colour diagnosticity. In the main experiment, participants adjusted sixteen such objects to their typical colour as well as to grey. If the achromatic object appears in its typical colour, then participants should adjust it to the opponent colour in order to subjectively perceive it as grey. We found that knowledge about the typical colour influences the colour appearance of artificial objects. This effect was particularly strong along the daylight axis. PMID:23145224

  7. 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

  8. Colour Coding of Maps for Colour Deficient Observers.

    PubMed

    Røise, Anne Kari; Kvitle, Anne Kristin; Green, Phil

    2016-01-01

    We evaluate the colour coding of a web map traffic information service based on profiles simulating colour vision deficiencies. Based on these simulations and principles for universal design, we propose adjustments of the existing colours creating more readable maps for the colour vision deficient observers. PMID:27534329

  9. Colour Coding of Maps for Colour Deficient Observers.

    PubMed

    Røise, Anne Kari; Kvitle, Anne Kristin; Green, Phil

    2016-01-01

    We evaluate the colour coding of a web map traffic information service based on profiles simulating colour vision deficiencies. Based on these simulations and principles for universal design, we propose adjustments of the existing colours creating more readable maps for the colour vision deficient observers.

  10. Simulating Colour Vision Deficiency from a Spectral Image.

    PubMed

    Shrestha, Raju

    2016-01-01

    People with colour vision deficiency (CVD) have difficulty seeing full colour contrast and can miss some of the features in a scene. As a part of universal design, researcher have been working on how to modify and enhance the colour of images in order to make them see the scene with good contrast. For this, it is important to know how the original colour image is seen by different individuals with CVD. This paper proposes a methodology to simulate accurate colour deficient images from a spectral image using cone sensitivity of different cases of deficiency. As the method enables generation of accurate colour deficient image, the methodology is believed to help better understand the limitations of colour vision deficiency and that in turn leads to the design and development of more effective imaging technologies for better and wider accessibility in the context of universal design. PMID:27534332

  11. Artificial selection for food colour preferences.

    PubMed

    Cole, Gemma L; Endler, John A

    2015-04-01

    Colour is an important factor in food detection and acquisition by animals using visually based foraging. Colour can be used to identify the suitability of a food source or improve the efficiency of food detection, and can even be linked to mate choice. Food colour preferences are known to exist, but whether these preferences are heritable and how these preferences evolve is unknown. Using the freshwater fish Poecilia reticulata, we artificially selected for chase behaviour towards two different-coloured moving stimuli: red and blue spots. A response to selection was only seen for chase behaviours towards the red, with realized heritabilities ranging from 0.25 to 0.30. Despite intense selection, no significant chase response was recorded for the blue-selected lines. This lack of response may be due to the motion-detection mechanism in the guppy visual system and may have novel implications for the evolvability of responses to colour-related signals. The behavioural response to several colours after five generations of selection suggests that the colour opponency system of the fish may regulate the response to selection. PMID:25740894

  12. Artificial selection for food colour preferences

    PubMed Central

    Cole, Gemma L.; Endler, John A.

    2015-01-01

    Colour is an important factor in food detection and acquisition by animals using visually based foraging. Colour can be used to identify the suitability of a food source or improve the efficiency of food detection, and can even be linked to mate choice. Food colour preferences are known to exist, but whether these preferences are heritable and how these preferences evolve is unknown. Using the freshwater fish Poecilia reticulata, we artificially selected for chase behaviour towards two different-coloured moving stimuli: red and blue spots. A response to selection was only seen for chase behaviours towards the red, with realized heritabilities ranging from 0.25 to 0.30. Despite intense selection, no significant chase response was recorded for the blue-selected lines. This lack of response may be due to the motion-detection mechanism in the guppy visual system and may have novel implications for the evolvability of responses to colour-related signals. The behavioural response to several colours after five generations of selection suggests that the colour opponency system of the fish may regulate the response to selection. PMID:25740894

  13. Artificial selection for food colour preferences.

    PubMed

    Cole, Gemma L; Endler, John A

    2015-04-01

    Colour is an important factor in food detection and acquisition by animals using visually based foraging. Colour can be used to identify the suitability of a food source or improve the efficiency of food detection, and can even be linked to mate choice. Food colour preferences are known to exist, but whether these preferences are heritable and how these preferences evolve is unknown. Using the freshwater fish Poecilia reticulata, we artificially selected for chase behaviour towards two different-coloured moving stimuli: red and blue spots. A response to selection was only seen for chase behaviours towards the red, with realized heritabilities ranging from 0.25 to 0.30. Despite intense selection, no significant chase response was recorded for the blue-selected lines. This lack of response may be due to the motion-detection mechanism in the guppy visual system and may have novel implications for the evolvability of responses to colour-related signals. The behavioural response to several colours after five generations of selection suggests that the colour opponency system of the fish may regulate the response to selection.

  14. Evolution of colour vision in mammals

    PubMed Central

    Jacobs, Gerald H.

    2009-01-01

    Colour vision allows animals to reliably distinguish differences in the distributions of spectral energies reaching the eye. Although not universal, a capacity for colour vision is sufficiently widespread across the animal kingdom to provide prima facie evidence of its importance as a tool for analysing and interpreting the visual environment. The basic biological mechanisms on which vertebrate colour vision ultimately rests, the cone opsin genes and the photopigments they specify, are highly conserved. Within that constraint, however, the utilization of these basic elements varies in striking ways in that they appear, disappear and emerge in altered form during the course of evolution. These changes, along with other alterations in the visual system, have led to profound variations in the nature and salience of colour vision among the vertebrates. This article concerns the evolution of colour vision among the mammals, viewing that process in the context of relevant biological mechanisms, of variations in mammalian colour vision, and of the utility of colour vision. PMID:19720656

  15. Colour stability of tooth-coloured restorative materials.

    PubMed

    Gaintantzopoulou, Marianna; Kakaboura, Afrodite; Vougiouklakis, Georgios

    2005-06-01

    The colour stability of the surface and in-depth (2 mm) layer of two resin composites, a laboratory second-generation resin composite and a compomer were evaluated after 24 and 360 hours of water aging under dark and UV light conditions. The influence of various polymerization techniques on color changes was also evaluated. Color differences (deltaE*) showed higher color changes under UV light exposure than under dark storage, both at 24- and 360-hour evaluations. Color changes were statistically higher at the 360-hour assessment, in both conditions of maintenance. Compomer was the least color stable of the materials tested. Additional polymerization significantly decreased the colour change of both composite resins.

  16. Colour Mixing Based on Daylight

    ERIC Educational Resources Information Center

    Meyn, Jan-Peter

    2008-01-01

    Colour science is based on the sensation of monochromatic light. In contrast to that, surface colours are caused by reflection of wide sections of the daylight spectrum. Non-spectral colours like magenta and purple appear homologous to colours with spectral hue, if the approach of mixing monochromatic light is abandoned. It is shown that a large…

  17. Categorical Effects in Children's Colour Search: A Cross-Linguistic Comparison

    ERIC Educational Resources Information Center

    Daoutis, Christine A.; Franklin, Anna; Riddett, Amy; Clifford, Alexandra; Davies, Ian R. L.

    2006-01-01

    In adults, visual search for a colour target is facilitated if the target and distractors fall in different colour categories (e.g. Daoutis, Pilling, & Davies, in press). The present study explored category effects in children's colour search. The relationship between linguistic colour categories and perceptual categories was addressed by…

  18. Bird colour vision: behavioural thresholds reveal receptor noise.

    PubMed

    Olsson, Peter; Lind, Olle; Kelber, Almut

    2015-01-15

    Birds have impressive physiological adaptations for colour vision, including tetrachromacy and coloured oil droplets, yet it is not clear exactly how well birds can discriminate the reflecting object colours that they encounter in nature. With behavioural experiments, we determined colour discrimination thresholds of chickens in bright and dim light. We performed the experiments with two colour series, orange and green, covering two parts of chicken colour space. These experiments allowed us to compare behavioural results with model expectations and determine how different noise types limit colour discrimination. At intensities ranging from bright light to those corresponding to early dusk (250-10 cd m(-2)), we describe thresholds accurately by assuming a constant signal-to-noise ratio, in agreement with an invariant Weber fraction of Weber's law. Below this intensity, signal-to-noise ratio decreases and Weber's law is violated because photon-shot noise limits colour discrimination. In very dim light (below 0.05 cd m(-2) for the orange series or 0.2 cd m(-2) for the green series) colour discrimination is possibly constrained by dark noise, and the lowest intensity at which chickens can discriminate colours is 0.025 and 0.08 cd m(-2) for the orange and green series, respectively. Our results suggest that chickens use spatial pooling of cone outputs to mitigate photon-shot noise. Surprisingly, we found no difference between colour discrimination of chickens and humans tested with the same test in bright light. PMID:25609782

  19. Bird colour vision: behavioural thresholds reveal receptor noise.

    PubMed

    Olsson, Peter; Lind, Olle; Kelber, Almut

    2015-01-15

    Birds have impressive physiological adaptations for colour vision, including tetrachromacy and coloured oil droplets, yet it is not clear exactly how well birds can discriminate the reflecting object colours that they encounter in nature. With behavioural experiments, we determined colour discrimination thresholds of chickens in bright and dim light. We performed the experiments with two colour series, orange and green, covering two parts of chicken colour space. These experiments allowed us to compare behavioural results with model expectations and determine how different noise types limit colour discrimination. At intensities ranging from bright light to those corresponding to early dusk (250-10 cd m(-2)), we describe thresholds accurately by assuming a constant signal-to-noise ratio, in agreement with an invariant Weber fraction of Weber's law. Below this intensity, signal-to-noise ratio decreases and Weber's law is violated because photon-shot noise limits colour discrimination. In very dim light (below 0.05 cd m(-2) for the orange series or 0.2 cd m(-2) for the green series) colour discrimination is possibly constrained by dark noise, and the lowest intensity at which chickens can discriminate colours is 0.025 and 0.08 cd m(-2) for the orange and green series, respectively. Our results suggest that chickens use spatial pooling of cone outputs to mitigate photon-shot noise. Surprisingly, we found no difference between colour discrimination of chickens and humans tested with the same test in bright light.

  20. Individual colour patches as multicomponent signals.

    PubMed

    Grether, Gregory F; Kolluru, Gita R; Nersissian, Karen

    2004-08-01

    Colour patches are complex traits, the components of which may evolve independently through a variety of mechanisms. Although usually treated as simple, two-dimensional characters and classified as either structural or pigmentary, in reality colour patches are complicated, three-dimensional structures that often contain multiple pigment types and structural features. The basic dermal chromatophore unit of fishes, reptiles and amphibians consists of three contiguous cell layers. Xanthophores and erythrophores in the outermost layer contain carotenoid and pteridine pigments that absorb short-wave light; iridophores in the middle layer contain crystalline platelets that reflect light back through the xanthophores; and melanophores in the basal layer contain melanins that absorb light across the spectrum. Changes in any one component of a chromatophore unit can drastically alter the reflectance spectrum produced, and for any given adaptive outcome (e.g. an increase in visibility), there may be multiple biochemical or cellular routes that evolution could take, allowing for divergent responses by different populations or species to similar selection regimes. All of the mechanisms of signal evolution that previously have been applied to single ornaments (including whole colour patches) could potentially be applied to the individual components of colour patches. To reach a complete understanding of colour patch evolution, however, it may be necessary to take an explicitly multi-trait approach. Here, we review multiple trait evolution theory and the basic mechanisms of colour production in fishes, reptiles and amphibians, and use a combination of computer simulations and empirical examples to show how multiple trait evolution theory can be applied to the components of single colour patches. This integrative perspective on animal colouration opens up a host of new questions and hypotheses. We offer specific, testable functional hypotheses for the most common pigmentary

  1. The many colours of 'the dress'.

    PubMed

    Gegenfurtner, Karl R; Bloj, Marina; Toscani, Matteo

    2015-06-29

    There has been an intense discussion among the public about the colour of a dress, shown in a picture posted originally on Tumblr (http://swiked.tumblr.com/post/112073818575/guys-please-help-me-is-this-dress-white-and; accessed on 10:56 am GMT on Tue 24 Mar 2015). Some people argue that they see a white dress with golden lace, while others describe the dress as blue with black lace. Here we show that the question "what colour is the dress?" has more than two answers. In fact, there is a continuum of colour percepts across different observers. We measured colour matches on a calibrated screen for two groups of observers who had reported different percepts of the dress. Surprisingly, differences between the two groups arose mainly from differences in lightness, rather than chromaticity of the colours they adjusted to match the dress. We speculate that the ambiguity arises in the case of this particular image because the distribution of colours within the dress closely matches the distribution of natural daylights. This makes it more difficult to disambiguate illumination changes from those in reflectance. PMID:25981790

  2. Three-dimensional plasmonic stereoscopic prints in full colour

    NASA Astrophysics Data System (ADS)

    Goh, Xiao Ming; Zheng, Yihan; Tan, Shawn J.; Zhang, Lei; Kumar, Karthik; Qiu, Cheng-Wei; Yang, Joel K. W.

    2014-11-01

    Metal nanostructures can be designed to scatter different colours depending on the polarization of the incident light. Such spectral control is attractive for applications such as high-density optical storage, but challenges remain in creating microprints with a single-layer architecture that simultaneously enables full-spectral and polarization control of the scattered light. Here we demonstrate independently tunable biaxial colour pixels composed of isolated nanoellipses or nanosquare dimers that can exhibit a full range of colours in reflection mode with linear polarization dependence. Effective polarization-sensitive full-colour prints are realized. With this, we encoded two colour images within the same area and further use this to achieve depth perception by realizing three-dimensional stereoscopic colour microprint. Coupled with the low cost and durability of aluminium as the functional material in our pixel design, such polarization-sensitive encoding can realize a wide spectrum of applications in colour displays, data storage and anti-counterfeiting technologies.

  3. Three-dimensional plasmonic stereoscopic prints in full colour.

    PubMed

    Goh, Xiao Ming; Zheng, Yihan; Tan, Shawn J; Zhang, Lei; Kumar, Karthik; Qiu, Cheng-Wei; Yang, Joel K W

    2014-11-04

    Metal nanostructures can be designed to scatter different colours depending on the polarization of the incident light. Such spectral control is attractive for applications such as high-density optical storage, but challenges remain in creating microprints with a single-layer architecture that simultaneously enables full-spectral and polarization control of the scattered light. Here we demonstrate independently tunable biaxial colour pixels composed of isolated nanoellipses or nanosquare dimers that can exhibit a full range of colours in reflection mode with linear polarization dependence. Effective polarization-sensitive full-colour prints are realized. With this, we encoded two colour images within the same area and further use this to achieve depth perception by realizing three-dimensional stereoscopic colour microprint. Coupled with the low cost and durability of aluminium as the functional material in our pixel design, such polarization-sensitive encoding can realize a wide spectrum of applications in colour displays, data storage and anti-counterfeiting technologies.

  4. Synaesthetic Colour in the Brain: Beyond Colour Areas. A Functional Magnetic Resonance Imaging Study of Synaesthetes and Matched Controls

    PubMed Central

    van Leeuwen, Tessa M.; Petersson, Karl Magnus; Hagoort, Peter

    2010-01-01

    Background In synaesthesia, sensations in a particular modality cause additional experiences in a second, unstimulated modality (e.g., letters elicit colour). Understanding how synaesthesia is mediated in the brain can help to understand normal processes of perceptual awareness and multisensory integration. In several neuroimaging studies, enhanced brain activity for grapheme-colour synaesthesia has been found in ventral-occipital areas that are also involved in real colour processing. Our question was whether the neural correlates of synaesthetically induced colour and real colour experience are truly shared. Methodology/Principal Findings First, in a free viewing functional magnetic resonance imaging (fMRI) experiment, we located main effects of synaesthesia in left superior parietal lobule and in colour related areas. In the left superior parietal lobe, individual differences between synaesthetes (projector-associator distinction) also influenced brain activity, confirming the importance of the left superior parietal lobe for synaesthesia. Next, we applied a repetition suppression paradigm in fMRI, in which a decrease in the BOLD (blood-oxygenated-level-dependent) response is generally observed for repeated stimuli. We hypothesized that synaesthetically induced colours would lead to a reduction in BOLD response for subsequently presented real colours, if the neural correlates were overlapping. We did find BOLD suppression effects induced by synaesthesia, but not within the colour areas. Conclusions/Significance Because synaesthetically induced colours were not able to suppress BOLD effects for real colour, we conclude that the neural correlates of synaesthetic colour experience and real colour experience are not fully shared. We propose that synaesthetic colour experiences are mediated by higher-order visual pathways that lie beyond the scope of classical, ventral-occipital visual areas. Feedback from these areas, in which the left parietal cortex is likely to

  5. Colour assortative pairing in a colour polymorphic lizard is independent of population morph diversity.

    PubMed

    Pérez I de Lanuza, Guillem; Font, Enrique; Carretero, Miguel Ángel

    2016-10-01

    Previous work with a colour polymorphic population of Podarcis muralis (Lacertidae) revealed that lizards pair by ventral colour, favouring the same colour (i.e. homomorphic) pairs. Such assortative pairing, which probably results in colour assortative mating, can have consequences for the genetic structure of the population and potentially promote speciation. The population previously studied, located in the Pyrenees, encompasses white, yellow and orange animals, as well as intermediate white-orange and yellow-orange morphs. However, other Pyrenean populations of P. muralis have less ventral colour morphs. Our aim in this study is to test the generality of the assortative colour pairing system, extending our previous analyses to populations with different morph compositions and frequencies. The results show that the assortative pattern of pairing is similar in all the populations analysed and, hence, independent of morph composition and not restricted to pentamorphic populations. This suggests that assortative pairing by colour is a general phenomenon for colour polymorphic populations of P. muralis. PMID:27649703

  6. Uropygial gland and bib colouration in the house sparrow

    PubMed Central

    2016-01-01

    Birds frequently signal different qualities by plumage colouration, mainly during mating. However, plumage colouration is determined during the moult, and therefore it would indicate the quality of individual birds during the moult, not its current quality. Recent studies, however, suggest that birds could modify plumage colouration by using cosmetic preen oil produced by the uropygial gland. In this study, I show that bib colouration is related to uropygial gland size and body condition in male house sparrows (Passer domesticus). Moreover, I conducted an experiment in which a group of sparrows were inoculated with an antigen, mimicking an illness. In control birds, short-term changes in bib colouration were related to both body condition and change in uropygial gland size. Therefore, birds that reduced uropygial gland size showed a greater colouration change. However, bib colouration did not change with the change in uropygial gland size in experimental birds inoculated with the antigen. Given that the experiment did not affect preen oil production or consumption, this finding tentatively suggests that the immune challenge provoked a change in the composition of preen oil, affecting its cosmetic properties. In short, the results of this study suggest that (1) male house sparrows produce cosmetic preen oil that alters the colouration of their bibs; (2) the more change in uropygial gland size, the more change in bib colouration; and (3) in this way, bib colouration has the potential to signal current health status, since less healthy birds showed less capacity to change bib colouration. PMID:27280079

  7. Uropygial gland and bib colouration in the house sparrow.

    PubMed

    Moreno-Rueda, Gregorio

    2016-01-01

    Birds frequently signal different qualities by plumage colouration, mainly during mating. However, plumage colouration is determined during the moult, and therefore it would indicate the quality of individual birds during the moult, not its current quality. Recent studies, however, suggest that birds could modify plumage colouration by using cosmetic preen oil produced by the uropygial gland. In this study, I show that bib colouration is related to uropygial gland size and body condition in male house sparrows (Passer domesticus). Moreover, I conducted an experiment in which a group of sparrows were inoculated with an antigen, mimicking an illness. In control birds, short-term changes in bib colouration were related to both body condition and change in uropygial gland size. Therefore, birds that reduced uropygial gland size showed a greater colouration change. However, bib colouration did not change with the change in uropygial gland size in experimental birds inoculated with the antigen. Given that the experiment did not affect preen oil production or consumption, this finding tentatively suggests that the immune challenge provoked a change in the composition of preen oil, affecting its cosmetic properties. In short, the results of this study suggest that (1) male house sparrows produce cosmetic preen oil that alters the colouration of their bibs; (2) the more change in uropygial gland size, the more change in bib colouration; and (3) in this way, bib colouration has the potential to signal current health status, since less healthy birds showed less capacity to change bib colouration.

  8. Diagnosing synaesthesia with online colour pickers: maximising sensitivity and specificity.

    PubMed

    Rothen, Nicolas; Seth, Anil K; Witzel, Christoph; Ward, Jamie

    2013-04-30

    The most commonly used method for formally assessing grapheme-colour synaesthesia (i.e., experiencing colours in response to letter and/or number stimuli) involves selecting colours from a large colour palette on several occasions and measuring consistency of the colours selected. However, the ability to diagnose synaesthesia using this method depends on several factors that have not been directly contrasted. These include the type of colour space used (e.g., RGB, HSV, CIELUV, CIELAB) and different measures of consistency (e.g., city block and Euclidean distance in colour space). This study aims to find the most reliable way of diagnosing grapheme-colour synaesthesia based on maximising sensitivity (i.e., ability of a test to identify true synaesthetes) and specificity (i.e., ability of a test to identify true non-synaesthetes). We show, applying ROC (receiver operating characteristics) to binary classification of a large sample of self-declared synaesthetes and non-synaesthetes, that the consistency criterion (i.e., cut-off value) for diagnosing synaesthesia is considerably higher than the current standard in the field. We also show that methods based on perceptual CIELUV and CIELAB colour models (rather than RGB and HSV colour representations) and Euclidean distances offer an even greater sensitivity and specificity than most currently used measures. Together, these findings offer improved heuristics for the behavioural assessment of grapheme-colour synaesthesia.

  9. Uropygial gland and bib colouration in the house sparrow.

    PubMed

    Moreno-Rueda, Gregorio

    2016-01-01

    Birds frequently signal different qualities by plumage colouration, mainly during mating. However, plumage colouration is determined during the moult, and therefore it would indicate the quality of individual birds during the moult, not its current quality. Recent studies, however, suggest that birds could modify plumage colouration by using cosmetic preen oil produced by the uropygial gland. In this study, I show that bib colouration is related to uropygial gland size and body condition in male house sparrows (Passer domesticus). Moreover, I conducted an experiment in which a group of sparrows were inoculated with an antigen, mimicking an illness. In control birds, short-term changes in bib colouration were related to both body condition and change in uropygial gland size. Therefore, birds that reduced uropygial gland size showed a greater colouration change. However, bib colouration did not change with the change in uropygial gland size in experimental birds inoculated with the antigen. Given that the experiment did not affect preen oil production or consumption, this finding tentatively suggests that the immune challenge provoked a change in the composition of preen oil, affecting its cosmetic properties. In short, the results of this study suggest that (1) male house sparrows produce cosmetic preen oil that alters the colouration of their bibs; (2) the more change in uropygial gland size, the more change in bib colouration; and (3) in this way, bib colouration has the potential to signal current health status, since less healthy birds showed less capacity to change bib colouration. PMID:27280079

  10. Rockpool Gobies Change Colour for Camouflage

    PubMed Central

    Stevens, Martin; Lown, Alice E.; Denton, Alexander M.

    2014-01-01

    Camouflage is found in a wide range of species living in numerous habitat types, offering protection from visually guided predators. This includes many species from the intertidal zone, which must cope with background types diverse in appearance and with multiple predator groups foraging at high and low tide. Many animals are capable of either relatively slow (hours, days, weeks) or rapid (seconds and minutes) colour change in order to better resemble the background against which they are found, but most work has been restricted to a few species or taxa. It is often suggested that many small intertidal fish are capable of colour change for camouflage, yet little experimental work has addressed this. Here, we test rock gobies (Gobius paganellus) for colour change abilities, and whether they can tune their appearance to match the background. In two experiments, we place gobies on backgrounds of different brightness (black or white), and of different colours (red and blue) and use digital image analysis and modelling of predator (avian) vision to quantify colour and luminance (perceived lightness) changes and camouflage. We find that gobies are capable of rapid colour change (occurring within one minute), and that they can change their luminance on lighter or darker backgrounds. When presented on backgrounds of different colours, gobies also change their colour (hue and saturation) while keeping luminance the same. These changes lead to predicted improvements in camouflage match to the background. Our study shows that small rockpool fish are capable of rapid visual change for concealment, and that this may be an important mechanism in many species to avoid predation, especially in complex heterogeneous environments. PMID:25333382

  11. Colour fluctuations in grapheme-colour synaesthesia: The effect of clinical and non-clinical mood changes.

    PubMed

    Kay, Collette L; Carmichael, Duncan A; Ruffell, Henry E; Simner, Julia

    2015-08-01

    Synaesthesia is a condition that gives rise to unusual secondary sensations (e.g., colours are perceived when listening to music). These unusual sensations tend to be reported as being stable throughout adulthood (e.g., Simner & Logie, 2007, Neurocase, 13, 358) and the consistency of these experiences over time is taken as the behavioural hallmark of genuineness. Our study looked at the influence of mood states on synaesthetic colours. In Experiment 1, we recruited grapheme-colour synaesthetes (who experience colours from letters/digits) and elicited their synaesthetic colours, as well as their mood and depression states, in two different testing sessions. In each session, participants completed the PANAS-X (Watson & Clark, 1999) and the BDI-II (Beck, Steer, & Brown, 1996, Manual for Beck Depression Inventory-II), and chose their synaesthetic colours for letters A-Z from an interactive colour palette. We found that negative mood significantly decreased the luminance of synaesthetic colours. In Experiment 2, we showed that synaesthetic colours were also less luminant for synaesthetes with anxiety disorder, versus those without. Additional evidence suggests that colour saturation, too, may inversely correlate with depressive symptoms. These results show that fluctuations in mood within both a normal and clinical range influence synaesthetic colours over time. This has implications for our understanding about the longitudinal stability of synaesthetic experiences, and of how mood may interact with the visual (imagery) systems. PMID:25413977

  12. Colour fluctuations in grapheme-colour synaesthesia: The effect of clinical and non-clinical mood changes.

    PubMed

    Kay, Collette L; Carmichael, Duncan A; Ruffell, Henry E; Simner, Julia

    2015-08-01

    Synaesthesia is a condition that gives rise to unusual secondary sensations (e.g., colours are perceived when listening to music). These unusual sensations tend to be reported as being stable throughout adulthood (e.g., Simner & Logie, 2007, Neurocase, 13, 358) and the consistency of these experiences over time is taken as the behavioural hallmark of genuineness. Our study looked at the influence of mood states on synaesthetic colours. In Experiment 1, we recruited grapheme-colour synaesthetes (who experience colours from letters/digits) and elicited their synaesthetic colours, as well as their mood and depression states, in two different testing sessions. In each session, participants completed the PANAS-X (Watson & Clark, 1999) and the BDI-II (Beck, Steer, & Brown, 1996, Manual for Beck Depression Inventory-II), and chose their synaesthetic colours for letters A-Z from an interactive colour palette. We found that negative mood significantly decreased the luminance of synaesthetic colours. In Experiment 2, we showed that synaesthetic colours were also less luminant for synaesthetes with anxiety disorder, versus those without. Additional evidence suggests that colour saturation, too, may inversely correlate with depressive symptoms. These results show that fluctuations in mood within both a normal and clinical range influence synaesthetic colours over time. This has implications for our understanding about the longitudinal stability of synaesthetic experiences, and of how mood may interact with the visual (imagery) systems.

  13. Colourful parrot feathers resist bacterial degradation.

    PubMed

    Burtt, Edward H; Schroeder, Max R; Smith, Lauren A; Sroka, Jenna E; McGraw, Kevin J

    2011-04-23

    The brilliant red, orange and yellow colours of parrot feathers are the product of psittacofulvins, which are synthetic pigments known only from parrots. Recent evidence suggests that some pigments in bird feathers function not just as colour generators, but also preserve plumage integrity by increasing the resistance of feather keratin to bacterial degradation. We exposed a variety of colourful parrot feathers to feather-degrading Bacillus licheniformis and found that feathers with red psittacofulvins degraded at about the same rate as those with melanin and more slowly than white feathers, which lack pigments. Blue feathers, in which colour is based on the microstructural arrangement of keratin, air and melanin granules, and green feathers, which combine structural blue with yellow psittacofulvins, degraded at a rate similar to that of red and black feathers. These differences in resistance to bacterial degradation of differently coloured feathers suggest that colour patterns within the Psittaciformes may have evolved to resist bacterial degradation, in addition to their role in communication and camouflage.

  14. Colour in flux: describing and printing colour in art

    NASA Astrophysics Data System (ADS)

    Parraman, Carinna

    2008-01-01

    This presentation will describe artists, practitioners and scientists, who were interested in developing a deeper psychological, emotional and practical understanding of the human visual system who were working with wavelength, paint and other materials. From a selection of prints at The Prints and Drawings Department at Tate London, the presentation will refer to artists who were motivated by issues relating to how colour pigment was mixed and printed, to interrogate and explain colour perception and colour science, and in art, how artists have used colour to challenge the viewer and how a viewer might describe their experience of colour. The title Colour in Flux refers, not only to the perceptual effect of the juxtaposition of one colour pigment with another, but also to the changes and challenges for the print industry. In the light of screenprinted examples from the 60s and 70s, the presentation will discuss 21 st century ideas on colour and how these notions have informed the Centre for Fine Print Research's (CFPR) practical research in colour printing. The latter part of this presentation will discuss the implications for the need to change methods in mixing inks that moves away from existing colour spaces, from non intuitive colour mixing to bespoke ink sets, colour mixing approaches and colour mixing methods that are not reliant on RGB or CMYK.

  15. 2-Colour photolithography.

    PubMed

    Fourkas, John T; Petersen, John S

    2014-05-21

    Photolithography is a crucial technology for both research and industry. The desire to be able to create ever finer features has fuelled a push towards lithographic methods that use electromagnetic radiation or charged particles with the shortest possible wavelength. At the same time, the physics and chemistry involved in employing light or particles with short wavelengths present great challenges. A new class of approaches to photolithography on the nanoscale involves the use of photoresists that can be activated with one colour of visible or near-ultraviolet light and deactivated with a second colour. Such methods hold the promise of attaining lithographic resolution that rivals or even exceeds that currently sought by industry, while at the same time using wavelengths of light that are inexpensive to produce and can be manipulated readily. The physical chemistry of 2-colour photolithography is a rich area of science that is only now beginning to be explored.

  16. Flower colour adaptation in a mimetic orchid

    PubMed Central

    Newman, Ethan; Anderson, Bruce; Johnson, Steven D.

    2012-01-01

    Although the tremendous variability in floral colour among angiosperms is often attributed to divergent selection by pollinators, it is usually difficult to preclude the possibility that floral colour shifts were driven by non-pollinator processes. Here, we examine the adaptive significance of flower colour in Disa ferruginea, a non-rewarding orchid that is thought to attract its butterfly pollinator by mimicking the flowers of sympatric nectar-producing species. Disa ferruginea has red flowers in the western part of its range and orange flowers in the eastern part—a colour shift that we hypothesized to be the outcome of selection for resemblance to different local nectar-producing plants. Using reciprocal translocations of red and orange phenotypes as well as arrays of artificial flowers, we found that the butterfly Aeropetes tulbaghia, the only pollinator of the orchid, preferred both the red phenotype and red artificial flowers in the west where its main nectar plant also has red flowers, and both the orange phenotype and orange artificial flowers in the east, where its main nectar plant has orange flowers. This phenotype by environment interaction demonstrates that the flower colour shift in D. ferruginea is adaptive and driven by local colour preference in its pollinator. PMID:22298842

  17. Flower colour adaptation in a mimetic orchid.

    PubMed

    Newman, Ethan; Anderson, Bruce; Johnson, Steven D

    2012-06-22

    Although the tremendous variability in floral colour among angiosperms is often attributed to divergent selection by pollinators, it is usually difficult to preclude the possibility that floral colour shifts were driven by non-pollinator processes. Here, we examine the adaptive significance of flower colour in Disa ferruginea, a non-rewarding orchid that is thought to attract its butterfly pollinator by mimicking the flowers of sympatric nectar-producing species. Disa ferruginea has red flowers in the western part of its range and orange flowers in the eastern part--a colour shift that we hypothesized to be the outcome of selection for resemblance to different local nectar-producing plants. Using reciprocal translocations of red and orange phenotypes as well as arrays of artificial flowers, we found that the butterfly Aeropetes tulbaghia, the only pollinator of the orchid, preferred both the red phenotype and red artificial flowers in the west where its main nectar plant also has red flowers, and both the orange phenotype and orange artificial flowers in the east, where its main nectar plant has orange flowers. This phenotype by environment interaction demonstrates that the flower colour shift in D. ferruginea is adaptive and driven by local colour preference in its pollinator.

  18. Flower Colour: How Bumblebees Handle Colours with Perceptually Changing Hues.

    PubMed

    Lunau, Klaus

    2016-03-21

    Colours are floral signals enabling bees to detect, inspect and discriminate flowers in a multitasking world. Behavioural tests now show that trained bumblebees find iridescent coloured targets more quickly and that weak iridescence does not corrupt target identification. PMID:27003883

  19. Flower Colour: How Bumblebees Handle Colours with Perceptually Changing Hues.

    PubMed

    Lunau, Klaus

    2016-03-21

    Colours are floral signals enabling bees to detect, inspect and discriminate flowers in a multitasking world. Behavioural tests now show that trained bumblebees find iridescent coloured targets more quickly and that weak iridescence does not corrupt target identification.

  20. Colour stability and visual perception of dimethacrylate based dental composite resins.

    PubMed

    Cook, W D; Chong, M P

    1985-07-01

    The spectrophotometric method of colour measurement was applied to an investigation of the colour stability of dimethacrylate based composite resins exposed to thermal and photochemical aging. A good correlation was observed between visual perception of colour change and the spectrophotometric colour difference [delta E (FMC-2)] of unexposed and aged specimens, but 50% of the observers considered the colour match of two specimens to be clinically unacceptable when the colour difference exceeded 10.6. Kinetic studies of thermally and photochemically induced colour change showed a sigmoidal dependence of colour change on the logarithm of exposure time. Because the direction and magnitude of the colour change differed for the two procedures, it would appear that different mechanisms are involved.

  1. Use of Descartes Folium Equation for Deriving a Relation between Total Aperture of Fractures after Uniaxial Compression and Strain Parameters of Different Rocks Exhibiting Negative Total Volumetric Strains

    NASA Astrophysics Data System (ADS)

    Palchik, V.

    2014-11-01

    The axial, crack and total volumetric strains, porosity, elastic constants, crack damage stresses, uniaxial compressive strengths, as well as fracture apertures and number of fracture traces in rock samples surface after compression were defined for different chalk, basalt, dolomite, granite, limestone and sandstone samples exhibiting negative total volumetric strain at failure. It is established that the total (summed) aperture of vertical fractures obtained on the lateral surface of rock sample is related to three characteristic strain parameters: axial strain at the onset of negative total volumetric strain, axial failure strain and negative total volumetric strain at failure. The relation is based on Descartes folium equation, where the length of the loop of folium is equal to axial strain coordinate at the onset of negative total volumetric strain. This relation shows that the total aperture increases according to power law with increasing difference between axial failure strain and axial strain at the onset of negative total volumetric strain. Simultaneously, an increase in this difference leads to an increase in the value of negative total volumetric strain at failure. It is found that a direct correlation between total aperture of fractures and negative total volumetric strain at failure is relatively weak. Nevertheless, total aperture of fractures tends to increase with increasing absolute value of negative total volumetric strain at failure. It is revealed that there is no connection between the number of fracture traces and negative total volumetric strain at failure.

  2. Impairment of colour vision in workers exposed to organic solvents

    PubMed Central

    Semple, S; Dick, F; Osborne, A; Cherrie, J; Soutar, A; Seaton, A; Haites, N

    2000-01-01

    OBJECTIVES—To investigate loss of colour vision related to exposure to solvents and the role of three enzyme polymorphisms in modifying the risk in exposed workers.
METHODS—A sample was studied of 68 male dockyard workers and 42 male community controls with and without neuropsychological symptoms from a previous cross sectional study. Indices of cumulative and intensity based exposure to solvents were calculated for all subjects. Alcohol, drug, and smoking histories were obtained. Colour vision was tested by Lanthony D15d colour vision test. Genotype of glutathione S-transferase M1 and T1 and N-acetyltransferase 2 polymorphisms were determined.
RESULTS—The relation between impairment of colour vision and exposure to solvents was investigated with multiple regression techniques. Increasing annual exposure to solvents was significantly associated with reduced colour vision (p=0.029). Impairment of colour vision was not associated with neuropsychological symptoms as measured by the Q16 solvent symptom questionnaire. No significant association was found between acquired impairment of colour vision and genetic polymorphisms when GSTM1, GSTT1 or NAT2 phenotypes were included in the analyses.
CONCLUSIONS—Exposure to mixed solvents is associated with impairment in colour vision, the risk increases with increasing exposure. The risk of impairment of colour vision was not altered in this study by the presence of different GSTM1, GSTT1 or NAT2 polymorphisms.


Keywords: colour vision; organic solvents; genetic polymorphisms PMID:10935938

  3. Fun with Colour

    ERIC Educational Resources Information Center

    Rennie, Richard

    2015-01-01

    The Australian Curriculum: Science for Year 5 includes "recognising that the colour of an object depends on the properties of the object and the color of the light source". This article shows how much more can be done with color in the science laboratory. Activities include using a prism to explore white light, using a hand lens to…

  4. Colour, vision and ergonomics.

    PubMed

    Pinheiro, Cristina; da Silva, Fernando Moreira

    2012-01-01

    This paper is based on a research project - Visual Communication and Inclusive Design-Colour, Legibility and Aged Vision, developed at the Faculty of Architecture of Lisbon. The research has the aim of determining specific design principles to be applied to visual communication design (printed) objects, in order to be easily read and perceived by all. This study target group was composed by a selection of socially active individuals, between 55 and 80 years, and we used cultural events posters as objects of study and observation. The main objective is to overlap the study of areas such as colour, vision, older people's colour vision, ergonomics, chromatic contrasts, typography and legibility. In the end we will produce a manual with guidelines and information to apply scientific knowledge into the communication design projectual practice. Within the normal aging process, visual functions gradually decline; the quality of vision worsens, colour vision and contrast sensitivity are also affected. As people's needs change along with age, design should help people and communities, and improve life quality in the present. Applying principles of visually accessible design and ergonomics, the printed design objects, (or interior spaces, urban environments, products, signage and all kinds of visually information) will be effective, easier on everyone's eyes not only for visually impaired people but also for all of us as we age.

  5. Colour-temperature correspondences: when reactions to thermal stimuli are influenced by colour.

    PubMed

    Ho, Hsin-Ni; Van Doorn, George H; Kawabe, Takahiro; Watanabe, Junji; Spence, Charles

    2014-01-01

    In our daily lives, information concerning temperature is often provided by means of colour cues, with red typically being associated with warm/hot, and blue with cold. While such correspondences have been known about for many years, they have primarily been studied using subjective report measures. Here we examined this correspondence using two more objective response measures. First, we used the Implicit Association Test (IAT), a test designed to assess the strength of automatic associations between different concepts in a given individual. Second, we used a priming task that involved speeded target discrimination in order to assess whether priming colour or thermal information could invoke the crossmodal association. The results of the IAT confirmed that the association exists at the level of response selection, thus indicating that a participant's responses to colour or thermal stimuli are influenced by the colour-temperature correspondence. The results of the priming experiment revealed that priming a colour affected thermal discrimination reaction times (RTs), but thermal cues did not influence colour discrimination responses. These results may therefore provide important clues as to the level of processing at which such colour-temperature correspondences are represented.

  6. Colour-Temperature Correspondences: When Reactions to Thermal Stimuli Are Influenced by Colour

    PubMed Central

    Ho, Hsin-Ni; Van Doorn, George H.; Kawabe, Takahiro; Watanabe, Junji; Spence, Charles

    2014-01-01

    In our daily lives, information concerning temperature is often provided by means of colour cues, with red typically being associated with warm/hot, and blue with cold. While such correspondences have been known about for many years, they have primarily been studied using subjective report measures. Here we examined this correspondence using two more objective response measures. First, we used the Implicit Association Test (IAT), a test designed to assess the strength of automatic associations between different concepts in a given individual. Second, we used a priming task that involved speeded target discrimination in order to assess whether priming colour or thermal information could invoke the crossmodal association. The results of the IAT confirmed that the association exists at the level of response selection, thus indicating that a participant’s responses to colour or thermal stimuli are influenced by the colour-temperature correspondence. The results of the priming experiment revealed that priming a colour affected thermal discrimination reaction times (RTs), but thermal cues did not influence colour discrimination responses. These results may therefore provide important clues as to the level of processing at which such colour-temperature correspondences are represented. PMID:24618675

  7. Colour-temperature correspondences: when reactions to thermal stimuli are influenced by colour.

    PubMed

    Ho, Hsin-Ni; Van Doorn, George H; Kawabe, Takahiro; Watanabe, Junji; Spence, Charles

    2014-01-01

    In our daily lives, information concerning temperature is often provided by means of colour cues, with red typically being associated with warm/hot, and blue with cold. While such correspondences have been known about for many years, they have primarily been studied using subjective report measures. Here we examined this correspondence using two more objective response measures. First, we used the Implicit Association Test (IAT), a test designed to assess the strength of automatic associations between different concepts in a given individual. Second, we used a priming task that involved speeded target discrimination in order to assess whether priming colour or thermal information could invoke the crossmodal association. The results of the IAT confirmed that the association exists at the level of response selection, thus indicating that a participant's responses to colour or thermal stimuli are influenced by the colour-temperature correspondence. The results of the priming experiment revealed that priming a colour affected thermal discrimination reaction times (RTs), but thermal cues did not influence colour discrimination responses. These results may therefore provide important clues as to the level of processing at which such colour-temperature correspondences are represented. PMID:24618675

  8. Adult total wellness: group differences based on sitting time and physical activity level

    PubMed Central

    2014-01-01

    Background An increasing body of evidence associates a high level of sitting time with poor health outcomes. The benefits of moderate to vigorous-intensity physical activities to various aspects of health are now well documented; however, individuals may engage in moderate-intensity physical activity for at least 30 minutes on five or more days of the week and still exhibit a high level of sitting time. This purpose of this study was to examine differences in total wellness among adults relative to high/low levels of sitting time combined with insufficient/sufficient physical activity (PA). The construct of total wellness incorporates a holistic approach to the body, mind and spirit components of life, an approach which may be more encompassing than some definitions of health. Methods Data were obtained from 226 adult respondents (27 ± 6 years), including 116 (51%) males and 110 (49%) females. Total PA and total sitting time were assessed with the International Physical Activity Questionnaire (IPAQ) (short-version). The Wellness Evaluation of Lifestyle Inventory was used to assess total wellness. An analysis of covariance (ANCOVA) was utilised to assess the effects of the sitting time/physical activity group on total wellness. A covariate was included to partial out the effects of age, sex and work status (student or employed). Cross-tabulations were used to show associations between the IPAQ derived high/low levels of sitting time with insufficient/sufficient PA and the three total wellness groups (i.e. high level of wellness, moderate wellness and wellness development needed). Results The majority of the participants were located in the high total sitting time and sufficient PA group. There were statistical differences among the IPAQ groups for total wellness [F (2,220) = 32.5 (p <0.001)]. A Chi-square test revealed a significant difference in the distribution of the IPAQ categories within the classification of wellness [χ2 (N = 226) = 54.5, p < .001

  9. Ultrasonic colour Doppler imaging

    PubMed Central

    Evans, David H.; Jensen, Jørgen Arendt; Nielsen, Michael Bachmann

    2011-01-01

    Ultrasonic colour Doppler is an imaging technique that combines anatomical information derived using ultrasonic pulse-echo techniques with velocity information derived using ultrasonic Doppler techniques to generate colour-coded maps of tissue velocity superimposed on grey-scale images of tissue anatomy. The most common use of the technique is to image the movement of blood through the heart, arteries and veins, but it may also be used to image the motion of solid tissues such as the heart walls. Colour Doppler imaging is now provided on almost all commercial ultrasound machines, and has been found to be of great value in assessing blood flow in many clinical conditions. Although the method for obtaining the velocity information is in many ways similar to the method for obtaining the anatomical information, it is technically more demanding for a number of reasons. It also has a number of weaknesses, perhaps the greatest being that in conventional systems, the velocities measured and thus displayed are the components of the flow velocity directly towards or away from the transducer, while ideally the method would give information about the magnitude and direction of the three-dimensional flow vectors. This review briefly introduces the principles behind colour Doppler imaging and describes some clinical applications. It then describes the basic components of conventional colour Doppler systems and the methods used to derive velocity information from the ultrasound signal. Next, a number of new techniques that seek to overcome the vector problem mentioned above are described. Finally, some examples of vector velocity images are presented. PMID:22866227

  10. A comparative study on antioxidant activities of different varieties of Solanum melongena.

    PubMed

    Nisha, P; Abdul Nazar, P; Jayamurthy, P

    2009-10-01

    Eggplant is one of most common vegetables consumed all around the world. The present study evaluates the antioxidant potential of four different varieties of eggplant (long green, purple coloured big size, purple coloured moderate size and purple coloured small size) in terms of total phenolic content, DPPH, total reducing power, superoxide radical scavenging activity, metal chelating activity and total anthocyanin content. Extracts from purple colour small size eggplant fruit demonstrated better antioxidant activities than the other samples which may be attributed to the higher phenolic and anthocyanin content since a linear relation was observed between the TPC and the antioxidant parameters.

  11. Semantic impairment disrupts perception, memory, and naming of secondary but not primary colours.

    PubMed Central

    Rogers, Timothy T.; Graham, Kim S.; Patterson, Karalyn

    2015-01-01

    To investigate how basic aspects of perception are shaped by acquired knowledge about the world, we assessed colour perception and cognition in patients with semantic dementia (SD), a disorder that progressively erodes conceptual knowledge. We observed a previously undocumented pattern of impairment to colour perception and cognition characterized by: (i) a normal ability to discriminate between only subtly different colours but an impaired ability to group different colours into categories, (ii) normal perception and memory for the colours red, green, and blue but impaired perception and memory for colours lying between these regions of a fully-saturated and luminant spectrum, and (iii) normal naming of polar colours in the opponent-process colour system (red, green, blue, yellow, white, and black) but impaired naming of other basic colours (brown, gray, pink, and orange). The results suggest that fundamental aspects of perception can be shaped by acquired knowledge about the world, but only within limits. PMID:25637227

  12. Semantic impairment disrupts perception, memory, and naming of secondary but not primary colours.

    PubMed

    Rogers, Timothy T; Graham, Kim S; Patterson, Karalyn

    2015-04-01

    To investigate how basic aspects of perception are shaped by acquired knowledge about the world, we assessed colour perception and cognition in patients with semantic dementia (SD), a disorder that progressively erodes conceptual knowledge. We observed a previously undocumented pattern of impairment to colour perception and cognition characterized by: (i) a normal ability to discriminate between only subtly different colours but an impaired ability to group different colours into categories, (ii) normal perception and memory for the colours red, green, and blue but impaired perception and memory for colours lying between these regions of a fully-saturated and luminant spectrum, and (iii) normal naming of polar colours in the opponent-process colour system (red, green, blue, yellow, white, and black) but impaired naming of other basic colours (brown, gray, pink, and orange). The results suggest that fundamental aspects of perception can be shaped by acquired knowledge about the world, but only within limits. PMID:25637227

  13. Effect of different cooking methods on total phenolic contents and antioxidant activities of four Boletus mushrooms.

    PubMed

    Sun, Liping; Bai, Xue; Zhuang, Yongliang

    2014-11-01

    The influences of cooking methods (steaming, pressure-cooking, microwaving, frying and boiling) on total phenolic contents and antioxidant activities of fruit body of Boletus mushrooms (B. aereus, B. badius, B. pinophilus and B. edulis) have been evaluated. The results showed that microwaving was better in retention of total phenolics than other cooking methods, while boiling significantly decreased the contents of total phenolics in samples under study. Effects of different cooking methods on phenolic acids profiles of Boletus mushrooms showed varieties with both the species of mushroom and the cooking method. Effects of cooking treatments on antioxidant activities of Boletus mushrooms were evaluated by in vitro assays of hydroxyl radical (OH·) -scavenging activity, reducing power and 1, 1-diphenyl-2-picrylhydrazyl radicals (DPPH·) -scavenging activity. Results indicated the changes of antioxidant activities of four Boletus mushrooms were different in five cooking methods. This study could provide some information to encourage food industry to recommend particular cooking methods. PMID:26396332

  14. False-colour palette generation using a reference colour gamut

    NASA Astrophysics Data System (ADS)

    Green, Phil

    2015-01-01

    Monochrome images are often converted to false-colour images, in which arbitrary colours are assigned to regions of the image to aid recognition of features within the image. Criteria for selection of colour palettes vary according to the application, but may include distinctiveness, extensibility, consistency, preference, meaningfulness and universality. A method for defining a palette from colours on the surface of a reference gamut is described, which ensures that all colours in the palette have the maximum chroma available for the given hue angle in the reference gamut. The palette can be re-targeted to a reproduction medium as needed using colour management, and this method ensures consistency between cross-media colour reproductions using the palette.

  15. Effects of cricket ball colour and illuminance levels on catching behaviour in professional cricketers.

    PubMed

    Scott, K; Kingsbury, D; Bennett, S; Davids, K; Langley, M

    2000-10-01

    In recent years there have been many alterations to equipment and technology in professional cricket, including the introduction of white balls during day-night matches. In the present study simulated slip-catching performance and movement initiation time were examined in professional cricketers when ball colour and illuminance levels differed. Five male professional cricketers (mean age: 27.3 +/- 1.4 years) volunteered to catch a total of 60 cricket balls, 20 (10 red and 10 white) under each of three illuminance levels (571, 1143 and 1714 lux). Balls were projected from a ball machine at 20 m s(-1) (45 mph) over a distance of 8.4 m, to the subject's dominant side. Catching performance was measured using an established catching scale. Movement initiation times for each hand were also calculated for each trial using a motion-analysis system. Data were submitted to separate two-way (ball colour [2] x illuminance level [3]) repeated measures analysis of variance. No significant effects were obtained for ball colour or illuminance levels for either catching performance or movement initiation time. Neither ball colour nor light level (within the range tested) affected slip-catching performance and movement initiation times in professional cricketers. Therefore it was concluded that the changes made to ball colour and light conditions in professional cricket were not detrimental to catching performance.

  16. COMMUNITY SCALE STREAM TAXA SENSITIVITIES TO DIFFERENT COMPOSITIONS OF EXCESS TOTAL DISSOLVED SOLIDS

    EPA Science Inventory

    Model stream chronic dosing studies (42 d) were conducted with three total dissolved solids (TDS) recipes. The recipes differed in composition of major ions. Community scale emergence was compared with single-species responses conducted simultaneously using the whole effluent tox...

  17. Evolution of vertebrate colour vision.

    PubMed

    Jacobs, Gerald H; Rowe, Mickey P

    2004-07-01

    Recent years have witnessed a growing interest in learning how colour vision has evolved. This trend has been fuelled by an enhanced understanding of the nature and extent of colour vision among contemporary species, by a deeper understanding of the paleontological record and by the application of new tools from molecular biology. This review provides an assessment of the progress in understanding the evolution of vertebrate colour vision. In so doing, we offer accounts of the evolution of three classes of mechanism important for colour vision--photopigment opsins, oil droplets and retinal organisation--and then examine details of how colour vision has evolved among mammals and, more specifically, among primates.

  18. Colour-rendition properties of solid-state lamps

    NASA Astrophysics Data System (ADS)

    Žukauskas, A.; Vaicekauskas, R.; Shur, M. S.

    2010-09-01

    design and optimization of multiwavelength LED clusters providing 'smart' illumination with a trade-off between different colour-rendition characteristics.

  19. Nocturnal colour vision in geckos.

    PubMed Central

    Roth, Lina S V; Kelber, Almut

    2004-01-01

    Nocturnal animals are said to sacrifice colour vision in favour of increased absolute sensitivity. This is true for most vertebrates that possess a dual retina with a single type of rod for colour-blind night vision and multiple types of cone for diurnal colour vision. However, among the nocturnal vertebrates, geckos are unusual because they have no rods but three cone types. Here, we show that geckos use their cones for colour vision in dim light. Two specimens of the nocturnal helmet gecko Tarentola (formerly Geckonia) chazaliae were able to discriminate blue from grey patterns by colour alone. Experiments were performed at 0.002 cd m(-2), a light intensity similar to dim moonlight. We conclude that nocturnal geckos can use cone-based colour vision at very dim light levels when humans rely on colour-blind rod vision. PMID:15801611

  20. Relationship between colouration and body condition in a crab spider that lures pollinators.

    PubMed

    Gawryszewski, Felipe M; Llandres, Ana L; Herberstein, Marie E

    2012-04-01

    Sit-and-wait predators have evolved several traits that increase the probability of encountering prey, including lures that attract prey. Although most crab spiders (Thomisidae) are known by their ability to change colour in order to match the background, a few use a different strategy. They are UV-reflective, creating a colour contrast against UV-absorbing flowers that is attractive for pollinators. The nature of the relationship between colour contrast and foraging success is unknown, as is how spiders trade off the potential costs and benefits of strong colour contrast. Therefore, this study investigated the relationship between spider colouration, foraging success and background colouration in a crab spider species known to lure pollinators via UV reflectance (Thomisus spectabilis). Field data revealed that spider body condition - a proxy of past foraging success - is positively related to overall colour contrast. We experimentally tested the effect of satiation and background colour on spider colour change. Throughout the experiment, spiders changed their colour contrast regardless of their food intake, suggesting that colour contrast and the UV component contributing to overall contrast are not caused by spider condition. Although spiders responded to different backgrounds by subtly changing their body colour, this did not result in colour matching. We believe that the observed variation in colour contrast and hence conspicuousness in the field, coupled with the spiders' reaction to our manipulation, could be the result of plasticity in response to prey.

  1. Genetics and evolution of colour patterns in reptiles.

    PubMed

    Olsson, Mats; Stuart-Fox, Devi; Ballen, Cissy

    2013-01-01

    The study of coloration in the polyphyletic reptilians has flourished in the last two decades, in particular with respect to the underlying genetics of colour traits, the function of colours in social interactions, and ongoing selection on these traits in the wild. The taxonomic bias, however, is profound: at this level of resolution almost all available information is for diurnal lizards. Therefore, we focus on case studies, for which there are as complete causal sequences of colour evolution as possible, from phenotypic expression of variation in colour, to ongoing selection in the wild. For work prior to 1992 and for a broader coverage of reptilian coloration we refer the readers to Cooper and Greenburg's (Biology of the Reptilia, 1992) review. There are seven major conclusions we would like to emphasise: (a) visual systems in diurnal lizards are broadly conserved but among the wider range of reptiles in general, there is functionally important variation in the number and type of photoreceptors, spectral tuning of photopigments and optical properties of the eye; (b) coloration in reptiles is a function of complex interactions between structural and pigmentary components, with implications for both proximate control and condition dependence of colour expression; (c) studies of colour-variable species have enabled estimates of heritability of colour and colour patterns, which often show a simple Mendelian pattern of inheritance; (d) colour-polymorphic lizard species sometimes, but not always, show striking differences in genetically encoded reproductive tactics and provide useful models for studying the evolution and maintenance of polymorphism; (e) both male and female colours are sometimes, but not always, a significant component of socio-sexual signalling, often based on multiple traits; (f) evidence for effects of hormones and condition on colour expression, and trade-offs with immunocompetence and parasite load, is variable; (g) lizards show fading of colours

  2. Effects of coloured lighting on the perception of interior spaces.

    PubMed

    Odabaşioğlu, Seden; Olguntürk, Nіlgün

    2015-02-01

    Use of coloured lighting in interior spaces has become prevalent in recent years. Considerable importance is ascribed to coloured lighting in interior and lighting design. The effects of colour on the perception of interior spaces have been studied as surface colour; but here, the effects of three different types of chromatic light were investigated. The lighting differed in colour (red, green and white) and perceptions of interior space were assessed. 97 participants (59 women, 38 men; M age = 21.4 yr.) evaluated the experiment room on a questionnaire assessing eight evaluative factors: Pleasantness, Arousal, Aesthetics, Usefulness, Comfort, Spaciousness, Colour, and Lighting quality. Perceptions of the room differed by colour of lighting for some of the evaluative factors, but there was no sex difference in perceptions. Interior spaces may be perceived as equally pleasant under white, green and red lighting. Under white lighting a space is perceived as more useful, spacious, clear, and luminous. Green lighting would make the same effect. Green and white lighting were perceived equally comfortable in an interior space. Chromatic coloured lighting was perceived to be more aesthetic than white lighting. The results support previous findings for some evaluative factors, but differed for others.

  3. Response of Phaseolus vulgaris L. to differing ozone regimes having identical total exposure

    NASA Astrophysics Data System (ADS)

    Musselman, Robert C.; Younglove, Theodore; McCool, Patrick M.

    Protocols were designed to test for differences in response of plants to ozone treatments having equal total exposure (concentration × time) but different exposure profiles Kidney beans ( Phaseolus vulgaris L., cv. California Dark Red) were exposed to ozone in controlled fumigation chambers within a greenhouse Four different ozone exposure profiles were used, each having the same total cumulative exposure (SUM00) and the same 7, 12 and 24 h seasonal means. The three exposure profiles which incorporated peak concentrations more severely impacted response parameters compared to a steady-state profile which did not exceed the National Ambient Air Quality Standard. Significant differences were found in percent necrotic leaf area, number of pods and top dry weight between exposure profiles. In additional analyses, the response parameters were regressed against seasonal cumulative ozone concentrations raised to powers of 0.33 and from 0.5 to 4 in steps of 0.5 in order to increase effective weighting of the higher concentrations. Total dry weight and leaf necrosis were best fit with the sum of the squared concentrations ( n = 2) while number of pods was best fit by the summed concentrations to the 3.5 power ( n = 3.5). These analyses suggest the peak ozone concentrations are important in determining plant response.

  4. Development of a forensic skin colour predictive test.

    PubMed

    Maroñas, Olalla; Phillips, Chris; Söchtig, Jens; Gomez-Tato, Antonio; Cruz, Raquel; Alvarez-Dios, José; de Cal, María Casares; Ruiz, Yarimar; Fondevila, Manuel; Carracedo, Ángel; Lareu, María V

    2014-11-01

    There is growing interest in skin colour prediction in the forensic field. However, a lack of consensus approaches for recording skin colour phenotype plus the complicating factors of epistatic effects, environmental influences such as exposure to the sun and unidentified genetic variants, present difficulties for the development of a forensic skin colour predictive test centred on the most strongly associated SNPs. Previous studies have analysed skin colour variation in single unadmixed population groups, including South Asians (Stokowski et al., 2007, Am. J. Hum. Genet, 81: 1119-32) and Europeans (Jacobs et al., 2013, Hum Genet. 132: 147-58). Nevertheless, a major challenge lies in the analysis of skin colour in admixed individuals, where co-ancestry proportions do not necessarily dictate any one person's skin colour. Our study sought to analyse genetic differences between African, European and admixed African-European subjects where direct spectrometric measurements and photographs of skin colour were made in parallel. We identified strong associations to skin colour variation in the subjects studied from a pigmentation SNP discovery panel of 59 markers and developed a forensic online classifier based on naïve Bayes analysis of the SNP profiles made. A skin colour predictive test is described using the ten most strongly associated SNPs in 8 genes linked to skin pigmentation variation. PMID:25082135

  5. 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.

  6. Content of total carotenoids in Calendula officinalis L. from different countries cultivated in Estonia.

    PubMed

    Raal, Ain; Kirsipuu, Kadri; Must, Reelika; Tenno, Silvi

    2009-01-01

    The aim of the present study was to investigate the content of total carotenoids in different collections of pot marigold (Calendula officinalis L.) inflorescences. Commercial seeds (42 samples) of C. officinalis were obtained from nine countries and cultivated in private gardens in three different counties of Estonia. The content of total carotenoids, determined spectrophotometrically (lambda=455 nm) varied in the investigated collections from 0.20 to 3.51%. The amount of pigments may depend on the type of plants, the importing company, the color of the ligulate and tubular florets, and the place and time of cultivation. For medicinal purposes, C. officinalis with brownish-yellow ligulate and tubular florets should be preferred. The best was found to be 'Golden Emperor' from Finland. PMID:19370871

  7. Accumulation of total mercury and methylmercury in rice plants collected from different mining areas in China.

    PubMed

    Meng, Mei; Li, Bing; Shao, Jun-juan; Wang, Thanh; He, Bin; Shi, Jian-bo; Ye, Zhi-hong; Jiang, Gui-bin

    2014-01-01

    A total of 155 rice plants were collected from ten mining areas in three provinces of China (Hunan, Guizhou and Guangdong), where most of mercury (Hg) mining takes place in China. During the harvest season, whole rice plants were sampled and divided into root, stalk & leaf, husk and seed (brown rice), together with soil from root zone. Although the degree of Hg contamination varied significantly among different mining areas, rice seed showed the highest ability for methylmercury (MeHg) accumulation. Both concentrations of total mercury (THg) and MeHg in rice plants were significantly correlated with Hg levels in soil, indicating soil is still an important source for both inorganic mercury (IHg) and MeHg in rice plants. The obvious discrepancy between the distribution patterns of THg and MeHg reflected different pathways of IHg and MeHg accumulation. Water soluble Hg may play more important role in MeHg accumulation in rice plants.

  8. Measuring the colour of rendering mortars

    NASA Astrophysics Data System (ADS)

    Govaerts, Yves; Meulebroeck, Wendy; Verdonck, Ann; de Bouw, Michael

    2014-05-01

    When restoring decorative mortar layers on historic façades, professionals need to determine the colour of these finishes in order to select an appropriate repair mortar. Currently, the appearance of these renders is only assessed from a subjective point of view. To match with the aesthetic aspects of the façade, contractors must constantly adjust their repair mortar composition to avoid a patchwork of different colours, which is detrimental for heritage. This time-consuming (trial-and-error) methodology can be excluded by evaluating `colour' with an objective numerical approach. The challenge of the research was to define and evaluate optimal material dependent boundary conditions for measuring the colour of nonhomogeneous mortars. Four samples with different scale of heterogeneity were measured by two spectrocolorimeters, both with a diffuse illumination geometry. The results were plotted in CIE-L*a*b* colour space. By calculating the colour difference (ΔE*), the influence of measuring with or without specular component was evaluated. We discovered the minimal number of measuring points depends on the scale of heterogeneity and the aperture area. The less homogeneous the mortar sample is and the smaller the aperture area, the more unique measuring points are required. Therefore, it is recommended to choose an aperture head of 25 mm or more to reduce the number of measurements, making your work time-efficient. However, in order to obtain accurate measurements on site, a portable optical spectrum analyser can be used with a 6 mm-diameter aperture, a viewing angle of 10°, SCI mode, illumination source D65, considering a minimum of 15 unique measuring points.

  9. 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

  10. 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.

  11. Correlation between dichromatic colour vision and jumping performance in horses.

    PubMed

    Spaas, Julie; Helsen, Werner F; Adriaenssens, Maurits; Broeckx, Sarah; Duchateau, Luc; Spaas, Jan H

    2014-10-01

    There is general agreement that horses have dichromatic colour vision with similar capabilities to human beings with red-green colour deficiencies. However, whether colour perception has an impact on equine jumping performance and how pronounced the colour stimulus might be for a horse is unknown. The present study investigated the relationship between the colour of the fences (blue or green) and the show jumping performance of 20 horses ridden by two riders using an indoor and outdoor set of green and blue fences. In the indoor arena, significantly more touches and faults were made on blue fences in comparison to green fences (median difference of 2.5 bars). When only touched bars were included, a significant median difference of one bar was found. Mares (n = 4) demonstrated more faults and had a significantly greater difference in touches and faults between the two colours than male horses (n = 16). Repeating the same experiment with eight horses in an outdoor grass arena revealed no significant differences between the two colours. In order to draw any definite conclusions, more research concerning the colour perception, influence of contrast with the arena surface and sex of horse is required.

  12. The signal in total-body plethysmography: errors due to adiabatic-isothermic difference.

    PubMed

    Chaui-Berlinck, J G; Bicudo, J E

    1998-09-01

    Total-body plethysmography is a technique often employed in comparative physiology studies because it avoids excessive handling of the animals. The pressure signal obtained is generated by an increase in internal energy of the gas phase of the system. Currently, this increase in internal energy is ascribed to heating (and water vapour saturation) of the inspired gas. The standard equation for computing tidal-volume implies that only temperature and saturation differences can be responsible for generating the ventilation signal. In this study, we were able to demonstrate that the difference between the external process of the thoracic expansion, which is adiabatic, and the internal process of it, which is isothermic, is an important factor of internal energy change in the total-body plethysmography method. In other words, organic tissues transfer heat to the entering gas but also to the present gas, in a way that keeps internal expansion an isothermic process. This extra amount of energy was never taken into account before. Therefore, experiments using such a technique to measure tidal-volume should be done using isothermic chambers. Moreover, due to uncertainties of the complementary measurements (ambient and lung temperatures, ambient water vapour saturation) needed to compute tidal-volume using total-body plethysmography, a minimal temperature difference about 15 degrees C between body and ambient should exist to keep uncertainties in tidal-volume values below 5%. However, this limit is not absolute, because it varies as a function of humidity and degree of uncertainty of the complementary measurements.

  13. Are all the coloured galaxias the same?

    NASA Astrophysics Data System (ADS)

    Hidalgo-Gámez, A. M.; Miranda-Pérez, B. E.; Vega-Acevedo, I.; Castañeda, H.; Saviane, I.

    2016-06-01

    The coloured galaxies were recently discovered in the data-base of the SDSS. They are all compact and show unsual colours in the gri composite image. The most studied so far are those called "green peas" because of their green colour but there are bright blue, purple, red, orange, grey and pink. The green, purple and blue also share a large equivalent width in the oxygen forbbiden line [OIII]5007, larger than 200 Å, being more intense than Hα. This is quite unsual even for star forming galaxies. Although some authors have concluded that all three are the same kind of galaxies, we have studied them carefully and found out that there are important differences among the properties, including the scaling relations.

  14. Another look at category effects on colour perception and their left hemispheric lateralisation: no evidence from a colour identification task.

    PubMed

    Suegami, Takashi; Aminihajibashi, Samira; Laeng, Bruno

    2014-05-01

    The present study aimed to replicate category effects on colour perception and their lateralisation to the left cerebral hemisphere (LH). Previous evidence for lateralisation of colour category effects has been obtained with tasks where a differently coloured target was searched within a display and participants reported the lateral location of the target. However, a left/right spatial judgment may yield LH-laterality effects per se. Thus, we employed an identification task that does not require a spatial judgment and used the same colour set that previously revealed LH-lateralised category effects. The identification task was better performed with between-category colours than with within-category task both in terms of accuracy and latency, but such category effects were bilateral or RH-lateralised, and no evidence was found for LH-laterality effects. The accuracy scores, moreover, indicated that the category effects derived from low sensitivities for within-blue colours and did not reflect the effects of categorical structures on colour perception. Furthermore, the classic "category effects" were observed in participants' response biases, instead of sensitivities. The present results argue against both the LH-lateralised category effects on colour perception and the existence of colour category effects per se.

  15. Colour and pattern change against visually heterogeneous backgrounds in the tree frog Hyla japonica

    PubMed Central

    Kang, Changku; Kim, Ye Eun; Jang, Yikweon

    2016-01-01

    Colour change in animals can be adaptive phenotypic plasticity in heterogeneous environments. Camouflage through background colour matching has been considered a primary force that drives the evolution of colour changing ability. However, the mechanism to which animals change their colour and patterns under visually heterogeneous backgrounds (i.e. consisting of more than one colour) has only been identified in limited taxa. Here, we investigated the colour change process of the Japanese tree frog (Hyla japonica) against patterned backgrounds and elucidated how the expression of dorsal patterns changes against various achromatic/chromatic backgrounds with/without patterns. Our main findings are i) frogs primarily responded to the achromatic differences in background, ii) their contrasting dorsal patterns were conditionally expressed dependent on the brightness of backgrounds, iii) against mixed coloured background, frogs adopted intermediate forms between two colours. Using predator (avian and snake) vision models, we determined that colour differences against different backgrounds yielded perceptible changes in dorsal colours. We also found substantial individual variation in colour changing ability and the levels of dorsal pattern expression between individuals. We discuss the possibility of correlational selection on colour changing ability and resting behaviour that maintains the high variation in colour changing ability within population. PMID:26932675

  16. Colour and pattern change against visually heterogeneous backgrounds in the tree frog Hyla japonica.

    PubMed

    Kang, Changku; Kim, Ye Eun; Jang, Yikweon

    2016-01-01

    Colour change in animals can be adaptive phenotypic plasticity in heterogeneous environments. Camouflage through background colour matching has been considered a primary force that drives the evolution of colour changing ability. However, the mechanism to which animals change their colour and patterns under visually heterogeneous backgrounds (i.e. consisting of more than one colour) has only been identified in limited taxa. Here, we investigated the colour change process of the Japanese tree frog (Hyla japonica) against patterned backgrounds and elucidated how the expression of dorsal patterns changes against various achromatic/chromatic backgrounds with/without patterns. Our main findings are i) frogs primarily responded to the achromatic differences in background, ii) their contrasting dorsal patterns were conditionally expressed dependent on the brightness of backgrounds, iii) against mixed coloured background, frogs adopted intermediate forms between two colours. Using predator (avian and snake) vision models, we determined that colour differences against different backgrounds yielded perceptible changes in dorsal colours. We also found substantial individual variation in colour changing ability and the levels of dorsal pattern expression between individuals. We discuss the possibility of correlational selection on colour changing ability and resting behaviour that maintains the high variation in colour changing ability within population. PMID:26932675

  17. Racial and Gender Differences in Willingness to Undergo Total Joint Replacement: The Johnston County Osteoarthritis Project

    PubMed Central

    Allen, Kelli D.; Golightly, Yvonne M.; Callahan, Leigh F.; Helmick, Charles G.; Ibrahim, Said A.; Kwoh, C. Kent; Renner, Jordan B.; Jordan, Joanne M.

    2014-01-01

    Objective Using data from the community-based Johnston County Osteoarthritis Project (JoCo OA), we examined race and gender variations in willingness to undergo, and perceptions regarding, total joint replacement (TJR). Methods Analyses were conducted for the total sample who participated in a follow-up measurement period from 2006-2010 (n=1,522) and a subsample with symptomatic hip and / or knee osteoarthritis (sOA; n=445). Participants indicated how willing they would be to have TJR (hip or knee) if their doctor recommended it; responses were categorized as “definitely” or “probably” willing vs. “unsure,” “probably not” or “definitely not” willing, or “don't know.” Participants answered seven questions regarding perceptions of TJR outcomes. Multivariable logistic regression models of willingness included participant characteristics (including socioeconomic status) and TJR perception variables that were associated with willingness at the p<0.1 level in bivariate analyses. Results African Americans had lower odds of willingness to undergo TJR than Caucasians in the total sample (adjusted OR = 0.57, 95% CI = 0.44-0.74) and the sOA subsample (adjusted OR = 0.39, 95% CI = 0.25-0.62). There were no gender differences in willingness. African Americans expected poorer TJR outcomes than Caucasians, but gender differences were minimal; perceptions of TJR outcomes were not significantly associated with willingness. Conclusions In this community sample, racial differences in TJR willingness and perceptions were substantial, but gender differences were small. Perceptions of TJR did not appear to affect willingness or explain racial differences in willingness. PMID:24470235

  18. Counting with Colours? Effect of Colours on the Numerical Abilities of House Crows (Corvus splendens) and Common Myna (Acridotheres tristis)

    PubMed Central

    Rahman, Nor Amira Abdul; Ali, Zalila; Zuharah, Wan Fatma; Fadzly, Nik

    2016-01-01

    We conducted several aviary experiments to investigate the influence of colours in quantity judgments of two species of birds; house crow (Corvus splendens) and common myna (Acridotheres tristis). Different quantity (in seven different food proportions) of mealworms were presented nonsequentially to all birds using artificially coloured red mealworms, for experiment 1, and using artificially coloured green mealworms, for experiment 2. Both red and green coloured mealworms have no significant effect on house crow’s quantity judgments (red: ANOVA: F6,30 = 1.748, p = 0.144; and green: ANOVA: F6,30= 1.085, p = 0.394). Common myna, however, showed a strong influence of red colour in their quantity judgment (ANOVA: F6,30 = 2.922, p = 0.023) as they succeeded in choosing the largest amount of food between two cups, but not when offered food using green coloured mealworms (ANOVA: F6,30 = 1.183, p = 0.342). In the next experiment, we hypothesised that both house crow and common myna will prefer red coloured food items over green coloured food items, when factors such as the amount of food is equal. We chose to test red and green colours because both colours play an important role in most avian food selections. Results showed that there were no significant differences in the selection of red or green coloured mealworms for both house crows (ANOVA: F6,30 = 2.310, p = 0.06) and common myna (ANOVA: F6,30 = 0.823, p = 0.561). PMID:27688847

  19. Counting with Colours? Effect of Colours on the Numerical Abilities of House Crows (Corvus splendens) and Common Myna (Acridotheres tristis)

    PubMed Central

    Rahman, Nor Amira Abdul; Ali, Zalila; Zuharah, Wan Fatma; Fadzly, Nik

    2016-01-01

    We conducted several aviary experiments to investigate the influence of colours in quantity judgments of two species of birds; house crow (Corvus splendens) and common myna (Acridotheres tristis). Different quantity (in seven different food proportions) of mealworms were presented nonsequentially to all birds using artificially coloured red mealworms, for experiment 1, and using artificially coloured green mealworms, for experiment 2. Both red and green coloured mealworms have no significant effect on house crow’s quantity judgments (red: ANOVA: F6,30 = 1.748, p = 0.144; and green: ANOVA: F6,30= 1.085, p = 0.394). Common myna, however, showed a strong influence of red colour in their quantity judgment (ANOVA: F6,30 = 2.922, p = 0.023) as they succeeded in choosing the largest amount of food between two cups, but not when offered food using green coloured mealworms (ANOVA: F6,30 = 1.183, p = 0.342). In the next experiment, we hypothesised that both house crow and common myna will prefer red coloured food items over green coloured food items, when factors such as the amount of food is equal. We chose to test red and green colours because both colours play an important role in most avian food selections. Results showed that there were no significant differences in the selection of red or green coloured mealworms for both house crows (ANOVA: F6,30 = 2.310, p = 0.06) and common myna (ANOVA: F6,30 = 0.823, p = 0.561).

  20. Effects of different fungal elicitors on growth, total carotenoids and astaxanthin formation by Xanthophyllomyces dendrorhous.

    PubMed

    Wang, Wenjun; Yu, Longjiang; Zhou, Pengpeng

    2006-01-01

    Six fungal elicitors prepared from Rhodotorula rubra, Rhodotorula glutinis, Panus conchatus, Coriolus versicolor, Mucor mucedo, Mortieralla alpina M-23 were examined to determine their effects on the growth, total carotenoids and astaxanthin formation by Xanthophyllomyces dendrorhous. The results showed that different fungal elicitor could cause diversely stimulating effects. Among the fungal elicitors tested, the M. mucedo elicitor concentration of 30 mg l(-1) promoted the biomass and total carotenoids yield most remarkably, resulting in 69.81+/-6.00% and 78.87+/-4.15% higher than the control, respectively. At the concentration of 30 mg l(-1), R. glutinis elicitor stimulated the highest astaxanthin yield with a 90.60+/-5.98% increase compared to the control. The R. rubra elicitor concentration of 30 mg l(-1) resulted in the optimal total carotenoids and astaxanthin content to be 42.24+/-0.49% and 69.02+/-0.72% higher than the control, respectively. At the concentration of 30 mg l(-1), R. rubra elicitor gave the highest increase in the ratio of astaxanthin in total carotenoids by 18.85+/-0.11% of the control.

  1. Measuring total health inequality: adding individual variation to group-level differences.

    PubMed

    Gakidou, Emmanuela; King, Gary

    2002-08-12

    BACKGROUND: Studies have revealed large variations in average health status across social, economic, and other groups. No study exists on the distribution of the risk of ill-health across individuals, either within groups or across all people in a society, and as such a crucial piece of total health inequality has been overlooked. Some of the reason for this neglect has been that the risk of death, which forms the basis for most measures, is impossible to observe directly and difficult to estimate. METHODS: We develop a measure of total health inequality - encompassing all inequalities among people in a society, including variation between and within groups - by adapting a beta-binomial regression model. We apply it to children under age two in 50 low- and middle-income countries. Our method has been adopted by the World Health Organization and is being implemented in surveys around the world; preliminary estimates have appeared in the World Health Report (2000). RESULTS: Countries with similar average child mortality differ considerably in total health inequality. Liberia and Mozambique have the largest inequalities in child survival, while Colombia, the Philippines and Kazakhstan have the lowest levels among the countries measured. CONCLUSIONS: Total health inequality estimates should be routinely reported alongside average levels of health in populations and groups, as they reveal important policy-related information not otherwise knowable. This approach enables meaningful comparisons of inequality across countries and future analyses of the determinants of inequality.

  2. Colour perception with changes in levels of illumination

    NASA Astrophysics Data System (ADS)

    Baah, Kwame F.; Green, Phil; Pointer, Michael

    2012-01-01

    The perceived colour of a stimulus depends on the conditions under which it is viewed. For colours employed as an important cue or identifier, such as signage and brand colours, colour reproduction tolerances are critically important. Typically, such stimuli would be judged using a known level of illumination but, in the target environment, the level of illumination used to view the samples may be entirely different. The effect of changes in the viewing condition on the perceptibility and acceptability of small colour differences should be understood when such tolerances and associated viewing conditions, are specified. A series of psychophysical experiments was conducted to determine whether changes in illumination level significantly alter acceptability and perceptibility thresholds of uniform colour stimuli. It was found that perceived colour discrimination thresholds varied by up to 2.0 ΔE00. For the perceptual correlate of hue however, this value could be of significance if the accepted error of colour difference was at the threshold, thereby yielding the possibility of rejection with changes in illumination level. Lightness and chroma on the other hand, exhibited greater tolerance and were less likely to be rejected with illuminance changes.

  3. Genetic analyses of the human eye colours using a novel objective method for eye colour classification.

    PubMed

    Andersen, Jeppe D; Johansen, Peter; Harder, Stine; Christoffersen, Susanne R; Delgado, Mikaela C; Henriksen, Sarah T; Nielsen, Mette M; Sørensen, Erik; Ullum, Henrik; Hansen, Thomas; Dahl, Anders L; Paulsen, Rasmus R; Børsting, Claus; Morling, Niels

    2013-09-01

    In this study, we present a new objective method for measuring the eye colour on a continuous scale that allows researchers to associate genetic markers with different shades of eye colour. With the use of the custom designed software Digital Iris Analysis Tool (DIAT), the iris was automatically identified and extracted from high resolution digital images. DIAT was made user friendly with a graphical user interface. The software counted the number of blue and brown pixels in the iris image and calculated a Pixel Index of the Eye (PIE-score) that described the eye colour quantitatively. The PIE-score ranged from -1 to 1 (brown to blue). The software eliminated the need for user based interpretation and qualitative eye colour categories. In 94% (570) of 605 analyzed eye images, the iris region was successfully extracted and a PIE-score was calculated. A very high correlation between the PIE-score and the human perception of eye colour was observed. The correlations between the PIE-scores and the six IrisPlex SNPs (HERC2 rs12913832, OCA2 rs1800407, SLC24A4 rs12896399, TYR rs1393350, SLC45A2 rs16891982 and IRF4 rs12203592) were analyzed in 570 individuals. Significant differences (p<10(-6)) in the PIE-scores of the individuals typed as HERC2 rs12913832 G (PIE=0.99) and rs12913832 GA (PIE=-0.71) or A (PIE=-0.87) were observed. We adjusted for the effect of HERC2 rs12913832 and showed that the quantitative PIE-scores were significantly associated with SNPs with minor effects (OCA2 rs1800407, SLC24A4 rs12896399 and TYR rs1393350) on the eye colour. We evaluated the two published prediction models for eye colour (IrisPlex [1] and Snipper[2]) and compared the predictions with the PIE-scores. We found good concordance with the prediction from individuals typed as HERC2 rs12913832 G. However, both methods had difficulties in categorizing individuals typed as HERC2 rs12913832 GA because of the large variation in eye colour in HERC2 rs12913832 GA individuals. With the use of

  4. New Evidence for Infant Colour Categories

    ERIC Educational Resources Information Center

    Franklin, Anna; Davies, Ian R. L.

    2004-01-01

    Bornstein, Kessen, and Weiskopf (1976) reported that pre-linguistic infants perceive colour categorically for primary boundaries: Following habituation, dishabituation only occurred if the test stimulus was from a different adult category to the original. Here, we replicated this important study and extended it to include secondary boundaries,…

  5. 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

  6. 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.

  7. Children Colouring: Speaking "Colour Difference" with Diversity Dolls

    ERIC Educational Resources Information Center

    Srinivasan, Prasanna; Cruz, Merlyne

    2015-01-01

    This article draws on data from qualitative research that was conducted with children between 6 and 13?years of age as a part of an 18-month project that explored respectfully engaging with cultural diversity in Australian primary schools. We used persona dolls as a research tool to enable children to explore and articulate their knowledge of…

  8. Novel coloured flowers.

    PubMed

    Mol, J; Cornish, E; Mason, J; Koes, R

    1999-04-01

    The floricultural industry has focused its attention primarily on the development of novel coloured and longer living cut flowers. The basis for this was laid down some years ago through the isolation of 'blue' genes and ethylene biosynthesis genes. Recently, a novel 'blue' gene has been discovered and yellow pigments were produced in petunias by addition of a new branch to the phenylpropanoid pathway. More insight was obtained into the sequestration of anthocyanin pigments into storage vacuoles. Significant progress has been achieved in the commercialisation of genetically modified flower varieties.

  9. Total ionizing dose effects of domestic SiGe HBTs under different dose rates

    NASA Astrophysics Data System (ADS)

    Liu, Mo-Han; Lu, Wu; Ma, Wu-Ying; Wang, Xin; Guo, Qi; He, Cheng-Fa; Jiang, Ke; Li, Xiao-Long; Xun, Ming-Zhu

    2016-03-01

    The total ionizing radiation (TID) response of commercial NPN silicon germanium hetero-junction bipolar transistors (SiGe HBTs) produced domestically are investigated under dose rates of 800 mGy(Si)/s and 1.3 mGy(Si)/s with a Co-60 gamma irradiation source. The changes of transistor parameters such as Gummel characteristics, and excess base current before and after irradiation, are examined. The results of the experiments show that for the KT1151, the radiation damage is slightly different under the different dose rates after prolonged annealing, and shows a time dependent effect (TDE). For the KT9041, however, the degradations of low dose rate irradiation is higher than for the high dose rate, demonstrating that there is a potential enhanced low dose rate sensitivity (ELDRS) effect for the KT9041. The possible underlying physical mechanisms of the different dose rates responses induced by the gamma rays are discussed.

  10. Coloured marking inside glass by laser radiation

    NASA Astrophysics Data System (ADS)

    Ligbado, Grace; Horn, Alexander; Kreutz, Ernst W.; Krauss, Manfred M.; Siedow, Norbert; Hensel, Hartmut

    2005-11-01

    Laser labelling inside glass induces micro-cracks by high energy densities in the focus. The micro-cracks reduce the mechanical stability of glass. Light scattering allows the observer to perceive the cracks as white pixels. Coloured marking of glass in this manner is not possible. Coloured marking inside glass by changing the oxidation state of the metal ions locally in the focus does not weaken the mechanical properties of the glass. Two kind of glass systems, lime-natron-silicate and borosilicate with 0.5 % mass-content of doping are investigated. The simultaneous presence of donators and acceptors allows a transition of electrons between polyvalent ions, and can lead to permanent colour-centres inside the glass, due to the fact that the absorption of the polyvalent ions is changed by the laser-induced conversion process. For this purpose a 3 ω Nd:YAG (wavelength λL = 355 nm, pulse duration t = 10 to 80 ns) and a Ti:Sapphire solid-state laser (wavelength λL = 810 nm, pulse duration t = 200 fs) are used. The radiation parameters and the chemical composition of the glass (mainly doping) are the dominant factors to generate coloured marking. The transmittance as a function of the fluence and the change of the absorption coefficient is measured and gives a statement of the colourshade. Further the difference between lime-natron-silicate and borosilicate glass (same doping variety) is examined. Actually mauve, yellow, red-brown an grey colouring can be produced. Cracks in the microstructure of glass can also be the cause for brown colour-centres generating.

  11. Optimality of the basic colour categories for classification

    PubMed Central

    Griffin, Lewis D

    2005-01-01

    Categorization of colour has been widely studied as a window into human language and cognition, and quite separately has been used pragmatically in image-database retrieval systems. This suggests the hypothesis that the best category system for pragmatic purposes coincides with human categories (i.e. the basic colours). We have tested this hypothesis by assessing the performance of different category systems in a machine-vision task. The task was the identification of the odd-one-out from triples of images obtained using a web-based image-search service. In each triple, two of the images had been retrieved using the same search term, the other a different term. The terms were simple concrete nouns. The results were as follows: (i) the odd-one-out task can be performed better than chance using colour alone; (ii) basic colour categorization performs better than random systems of categories; (iii) a category system that performs better than the basic colours could not be found; and (iv) it is not just the general layout of the basic colours that is important, but also the detail. We conclude that (i) the results support the plausibility of an explanation for the basic colours as a result of a pressure-to-optimality and (ii) the basic colours are good categories for machine vision image-retrieval systems. PMID:16849219

  12. The lavender plumage colour in Japanese quail is associated with a complex mutation in the region of MLPH that is related to differences in growth, feed consumption and body temperature

    PubMed Central

    2012-01-01

    Background The lavender phenotype in quail is a dilution of both eumelanin and phaeomelanin in feathers that produces a blue-grey colour on a wild-type feather pattern background. It has been previously demonstrated by intergeneric hybridization that the lavender mutation in quail is homologous to the same phenotype in chicken, which is caused by a single base-pair change in exon 1 of MLPH. Results In this study, we have shown that a mutation of MLPH is also associated with feather colour dilution in quail, but that the mutational event is extremely different. In this species, the lavender phenotype is associated with a non-lethal complex mutation involving three consecutive overlapping chromosomal changes (two inversions and one deletion) that have consequences on the genomic organization of four genes (MLPH and the neighbouring PRLH, RAB17 and LRRFIP1). The deletion of PRLH has no effect on the level of circulating prolactin. Lavender birds have lighter body weight, lower body temperature and increased feed consumption and residual feed intake than wild-type plumage quail, indicating that this complex mutation is affecting the metabolism and the regulation of homeothermy. Conclusions An extensive overlapping chromosome rearrangement was associated with a non-pathological Mendelian trait and minor, non deleterious effects in the lavender Japanese quail which is a natural knockout for PRLH. PMID:22937744

  13. Colour thresholding and objective quantification in bioimaging

    NASA Technical Reports Server (NTRS)

    Fermin, C. D.; Gerber, M. A.; Torre-Bueno, J. R.

    1992-01-01

    Computer imaging is rapidly becoming an indispensable tool for the quantification of variables in research and medicine. Whilst its use in medicine has largely been limited to qualitative observations, imaging in applied basic sciences, medical research and biotechnology demands objective quantification of the variables in question. In black and white densitometry (0-256 levels of intensity) the separation of subtle differences between closely related hues from stains is sometimes very difficult. True-colour and real-time video microscopy analysis offer choices not previously available with monochrome systems. In this paper we demonstrate the usefulness of colour thresholding, which has so far proven indispensable for proper objective quantification of the products of histochemical reactions and/or subtle differences in tissue and cells. In addition, we provide interested, but untrained readers with basic information that may assist decisions regarding the most suitable set-up for a project under consideration. Data from projects in progress at Tulane are shown to illustrate the advantage of colour thresholding over monochrome densitometry and for objective quantification of subtle colour differences between experimental and control samples.

  14. Digital colour management system for colour parameters reconstruction

    NASA Astrophysics Data System (ADS)

    Grudzinski, Karol; Lasmanowicz, Piotr; Assis, Lucas M. N.; Pawlicka, Agnieszka; Januszko, Adam

    2013-10-01

    Digital Colour Management System (DCMS) and its application to new adaptive camouflage system are presented in this paper. The DCMS is a digital colour rendering method which would allow for transformation of a real image into a set of colour pixels displayed on a computer monitor. Consequently, it can analyse pixels' colour which comprise images of the environment such as desert, semi-desert, jungle, farmland or rocky mountain in order to prepare an adaptive camouflage pattern most suited for the terrain. This system is described in present work as well as the use the subtractive colours mixing method to construct the real time colour changing electrochromic window/pixel (ECD) for camouflage purpose. The ECD with glass/ITO/Prussian Blue(PB)/electrolyte/CeO2-TiO2/ITO/glass configuration was assembled and characterized. The ECD switched between green and yellow after +/-1.5 V application and the colours have been controlled by Digital Colour Management System and described by CIE LAB parameters.

  15. Dosimetric evaluation of total marrow irradiation using 2 different planning systems.

    PubMed

    Nalichowski, Adrian; Eagle, Don G; Burmeister, Jay

    2016-01-01

    This study compared 2 different treatment planning systems (TPSs) for quality and efficiency of total marrow irradiation (TMI) plans. The TPSs used in this study were VOxel-Less Optimization (VoLO) (Accuray Inc, Sunnyvale, CA) using helical dose delivery on a Tomotherapy Hi-Art treatment unit and Eclipse (Varian Medical Systems Inc, Palo Alto, CA) using volumetric modulated arc therapy (VMAT) dose delivery on a Varian iX treatment unit. A total dose of 1200cGy was prescribed to cover 95% of the planning target volume (PTV). The plans were optimized and calculated based on a single CT data and structure set using the Alderson Rando phantom (The Phantom Laboratory, Salem, NY) and physician contoured target and organ at risk (OAR) volumes. The OARs were lungs, heart, liver, kidneys, brain, and small bowel. The plans were evaluated based on plan quality, time to optimize the plan and calculate the dose, and beam on time. The resulting mean and maximum doses to the PTV were 1268 and 1465cGy for VoLO and 1284 and 1541cGy for Eclipse, respectively. For 5 of 6 OAR structures the VoLO system achieved lower mean and D10 doses ranging from 22% to 52% and 3% to 44%, respectively. Total computational time including only optimization and dose calculation were 0.9 hours for VoLO and 3.8 hours for Eclipse. These times do not include user-dependent target delineation and field setup. Both planning systems are capable of creating high-quality plans for total marrow irradiation. The VoLO planning system was able to achieve more uniform dose distribution throughout the target volume and steeper dose fall off, resulting in superior OAR sparing. VoLO׳s graphics processing unit (GPU)-based optimization and dose calculation algorithm also allowed much faster creation of TMI plans. PMID:27372384

  16. Iodide-assisted total lead measurement and determination of different lead fractions in drinking water samples.

    PubMed

    Zhang, Yuanyuan; Ng, Ding-Quan; Lin, Yi-Pin

    2012-07-01

    Lead and its compounds are toxic and can harm human health, especially the intelligence development in children. Accurate measurement of total lead present in drinking water is crucial in determining the extent of lead contamination and human exposure due to drinking water consumption. The USEPA method for total lead measurement (no. 200.8) is often used to analyze lead levels in drinking water. However, in the presence of high concentration of the tetravalent lead corrosion product PbO(2), the USEPA method was not able to fully recover particulate lead due to incomplete dissolution of PbO(2) particles during strong acid digestion. In this study, a new procedure that integrates membrane separation, iodometric PbO(2) measurement, strong acid digestion and ICP-MS measurement was proposed and evaluated for accurate total lead measurement and quantification of different lead fractions including soluble Pb(2+), particulate Pb(II) carbonate and PbO(2) in drinking water samples. The proposed procedure was evaluated using drinking water reconstituted with spiked Pb(2+), spiked particulate Pb(II) carbonate and in situ formed or spiked PbO(2). Recovery tests showed that the proposed procedure and the USEPA method can achieve 93-112% and 86-103% recoveries respectively for samples containing low PbO(2) concentrations (0.018-0.076 mg Pb per L). For samples containing higher concentrations of PbO(2) (0.089-1.316 mg Pb per L), the USEPA method failed to meet the recovery requirement for total lead (85-115%) while the proposed method can achieve satisfactory recoveries (91-111%) and differentiate the soluble Pb(2+), particulate Pb(II) carbonate and PbO(2).

  17. Colour in Learning: Its Effect on the Retention Rate of Graduate Students

    ERIC Educational Resources Information Center

    Olurinola, Oluwakemi; Tayo, Omoniyi

    2015-01-01

    Cognitive psychologists have discovered different design principles to enhance memory performance. It has been said that retrieving process depends on many variables and one of them is colour. This paper provides an overview of research on colour and learning. It includes the effect of colour on attention, retention and memory performance, and…

  18. Environmental and hormonal factors controlling reversible colour change in crab spiders.

    PubMed

    Llandres, Ana L; Figon, Florent; Christidès, Jean-Philippe; Mandon, Nicole; Casas, Jérôme

    2013-10-15

    Habitat heterogeneity that occurs within an individual's lifetime may favour the evolution of reversible plasticity. Colour reversibility has many different functions in animals, such as thermoregulation, crypsis through background matching and social interactions. However, the mechanisms underlying reversible colour changes are yet to be thoroughly investigated. This study aims to determine the environmental and hormonal factors underlying morphological colour changes in Thomisus onustus crab spiders and the biochemical metabolites produced during these changes. We quantified the dynamics of colour changes over time: spiders were kept in yellow and white containers under natural light conditions and their colour was measured over 15 days using a spectrophotometer. We also characterised the chemical metabolites of spiders changing to a yellow colour using HPLC. Hormonal control of colour change was investigated by injecting 20-hydroxyecdysone (20E) into spiders. We found that background colouration was a major environmental factor responsible for colour change in crab spiders: individuals presented with white and yellow backgrounds changed to white and yellow colours, respectively. An ommochrome precursor, 3-OH-kynurenine, was the main pigment responsible for yellow colour. Spiders injected with 20E displayed a similar rate of change towards yellow colouration as spiders kept in yellow containers and exposed to natural sunlight. This study demonstrates novel hormonal manipulations that are capable of inducing reversible colour change.

  19. Sequestration of total and methyl mercury in different subcellular pools in marine caged fish.

    PubMed

    Onsanit, Sarayut; Wang, Wen-Xiong

    2011-12-30

    Mercury contamination is an important issue in marine fish, and can cause toxicity to human by fish consumption. Many studies have measured the mercury concentrations in fish and estimated the threshold levels of its risk to human, but the mercury sequestration in different subcellular pools of fish is unclear. In this study, we investigated the concentration and distribution of total mercury (THg) and methylmercury (MeHg) in different subcellular fractions in the farmed red seabream, red drum, and black seabream from Fujian marine fish farms, China. We found that both THg and MeHg were dominantly bound with the cellular debris, followed by metallothionein-like protein>metal-rich granule>heat-denatured protein>organelles pools. In general, Hg bound with the metal-sensitive fraction was small, indicating that Hg may have little toxicity to the fish (muscle). For the first time we showed that MTLP fraction had the highest % of total Hg as MeHg (88-91%) among all the subcellular fractions. Furthermore, the mercury concentration and subcellular distribution in the black seabream were both dependent on the fish size. Subcellular study may shed light on the detoxification of marine fish to Hg exposure and the potential bioavailability to humans due to fish consumption. PMID:22056886

  20. There's more to taste in a coloured bowl.

    PubMed

    Harrar, Vanessa; Piqueras-Fiszman, Betina; Spence, Charles

    2011-01-01

    The flavour and pleasantness of food and drinks are affected by their colour, their texture or crunch, and even by the shape and weight of the plate or glass. But, can the colour of the bowl also affect the taste of the food it contains? To answer this question we served popcorn in four different coloured bowls, and participants rated sweetness, saltiness, and overall liking. The sweet popcorn, in addition to being sweet, was perceived as saltier when eaten out of a coloured (as compared to a white) bowl, and vice versa for the salty popcorn. These results demonstrate that colour in bowl design can be used to elicit perceptions of sweetness and saltiness in real foods.

  1. Detection of bright and dim colours by honeybees.

    PubMed

    Hempel De Ibarra, N; Vorobyev, M; Brandt, R; Giurfa, M

    2000-11-01

    Honeybees, Apis mellifera, were trained to detect coloured disks with either a strong or a weak intensity difference against the background. Green, blue, ultraviolet-reflecting white and grey papers were reciprocally combined as targets or backgrounds, providing strong chromatic and/or achromatic cues. The behavioural performance of the honeybees was always symmetrical for both reciprocal target/background combinations of a colour pair, thus showing that target detection is independent of whether the colour is presented as a background or as a target in combination with the other colour. Bright targets against dim backgrounds and vice versa were detected more reliably than dim target/background combinations. This result favours the general assumption that the detectability of a coloured stimulus increases with increasing intensity.

  2. Colour mimicry and sexual deception by Tongue orchids (Cryptostylis).

    PubMed

    Gaskett, A C; Herberstein, M E

    2010-01-01

    Typically, floral colour attracts pollinators by advertising rewards such as nectar, but how does colour function when pollinators are deceived, unrewarded, and may even suffer fitness costs? Sexually deceptive orchids are pollinated only by male insects fooled into mating with orchid flowers and inadvertently transferring orchid pollinia. Over long distances, sexually deceptive orchids lure pollinators with counterfeit insect sex pheromones, but close-range deception with colour mimicry is a tantalising possibility. Here, for the first time, we analyse the colours of four sexually deceptive Cryptostylis orchid species and the female wasp they mimic (Lissopimpla excelsa, Ichneumonidae), from the perspective of the orchids' single, shared pollinator, male Lissopimpla excelsa. Despite appearing different to humans, the colours of the orchids and female wasps were effectively identical when mapped into a hymenopteran hexagonal colour space. The orchids and wasps reflected predominantly red-orange wavelengths, but UV was also reflected by raised bumps on two orchid species and by female wasp wings. The orchids' bright yellow pollinia contrasted significantly with their overall red colour. Orchid deception may therefore involve accurate and species-specific mimicry of wavelengths reflected by female wasps, and potentially, exploitation of insects' innate attraction to UV and yellow wavelengths. In general, mimicry may be facilitated by exploiting visual vulnerabilities and evolve more readily at the peripheries of sensory perception. Many sexually deceptive orchids are predominantly red, green or white: colours that are all potentially difficult for hymenoptera to detect or distinguish from the background.

  3. Colour mimicry and sexual deception by Tongue orchids (Cryptostylis).

    PubMed

    Gaskett, A C; Herberstein, M E

    2010-01-01

    Typically, floral colour attracts pollinators by advertising rewards such as nectar, but how does colour function when pollinators are deceived, unrewarded, and may even suffer fitness costs? Sexually deceptive orchids are pollinated only by male insects fooled into mating with orchid flowers and inadvertently transferring orchid pollinia. Over long distances, sexually deceptive orchids lure pollinators with counterfeit insect sex pheromones, but close-range deception with colour mimicry is a tantalising possibility. Here, for the first time, we analyse the colours of four sexually deceptive Cryptostylis orchid species and the female wasp they mimic (Lissopimpla excelsa, Ichneumonidae), from the perspective of the orchids' single, shared pollinator, male Lissopimpla excelsa. Despite appearing different to humans, the colours of the orchids and female wasps were effectively identical when mapped into a hymenopteran hexagonal colour space. The orchids and wasps reflected predominantly red-orange wavelengths, but UV was also reflected by raised bumps on two orchid species and by female wasp wings. The orchids' bright yellow pollinia contrasted significantly with their overall red colour. Orchid deception may therefore involve accurate and species-specific mimicry of wavelengths reflected by female wasps, and potentially, exploitation of insects' innate attraction to UV and yellow wavelengths. In general, mimicry may be facilitated by exploiting visual vulnerabilities and evolve more readily at the peripheries of sensory perception. Many sexually deceptive orchids are predominantly red, green or white: colours that are all potentially difficult for hymenoptera to detect or distinguish from the background. PMID:19798479

  4. Children's Models about Colours in Nahuatl-Speaking Communities

    NASA Astrophysics Data System (ADS)

    Gallegos-Cázares, Leticia; Flores-Camacho, Fernando; Calderón-Canales, Elena; Perrusquía-Máximo, Elvia; García-Rivera, Beatriz

    2014-10-01

    This paper presents the development and structure of indigenous children's ideas about mixing colours as well as their ideas about each colour, derived from their traditions. The children were interviewed both at school and outside it, and an educational proposal was implemented. Ideas expressed in the school context were analysed using the partial possible model, which states that the inferences and explanations used to describe a subject consist of constricting ideas, rules of correspondence, and a set of phenomenological inferences about processes. After identifying these components in the children's ideas, we developed models to describe their conceptions about mixing colours. We employed a different approach to analyse children's ideas related to their cultural context. The results showed that children change from a conception that focuses on colours as entities that do not change and as properties of objects (model 1) to the idea that colour represents a quality of substances or objects that can be modified by mixing colours (model 2). Cultural context analysis showed that stories are independent from one another and that they are not connected to colour mixing processes, only to the actions of colour on people. We concluded that students generate independent constructions between school and cultural knowledge.

  5. Colour mimicry and sexual deception by Tongue orchids ( Cryptostylis)

    NASA Astrophysics Data System (ADS)

    Gaskett, A. C.; Herberstein, M. E.

    2010-01-01

    Typically, floral colour attracts pollinators by advertising rewards such as nectar, but how does colour function when pollinators are deceived, unrewarded, and may even suffer fitness costs? Sexually deceptive orchids are pollinated only by male insects fooled into mating with orchid flowers and inadvertently transferring orchid pollinia. Over long distances, sexually deceptive orchids lure pollinators with counterfeit insect sex pheromones, but close-range deception with colour mimicry is a tantalising possibility. Here, for the first time, we analyse the colours of four sexually deceptive Cryptostylis orchid species and the female wasp they mimic ( Lissopimpla excelsa, Ichneumonidae), from the perspective of the orchids’ single, shared pollinator, male Lissopimpla excelsa. Despite appearing different to humans, the colours of the orchids and female wasps were effectively identical when mapped into a hymenopteran hexagonal colour space. The orchids and wasps reflected predominantly red-orange wavelengths, but UV was also reflected by raised bumps on two orchid species and by female wasp wings. The orchids’ bright yellow pollinia contrasted significantly with their overall red colour. Orchid deception may therefore involve accurate and species-specific mimicry of wavelengths reflected by female wasps, and potentially, exploitation of insects’ innate attraction to UV and yellow wavelengths. In general, mimicry may be facilitated by exploiting visual vulnerabilities and evolve more readily at the peripheries of sensory perception. Many sexually deceptive orchids are predominantly red, green or white: colours that are all potentially difficult for hymenoptera to detect or distinguish from the background.

  6. The development of artists' novel colour palettes for inkjet printing

    NASA Astrophysics Data System (ADS)

    Parraman, Carinna

    2010-01-01

    In this changing environment in which the artist and designer has access to a wide range of digital imaging tools and technologies, that on first glance, are dedicated to the creation of colour mixtures, why is the digital interface and colour outcome often disappointing? It appears that hardware, software tools and methods for digital printing are not necessarily suited to the specific requirements of the artist. In fact, they are too generalised to obtain a high degree of quality and too inflexible to allow artists to obtain precision and predictability. Is it possible for an artist to mix and print a colour that captures their creative imagination? The motivation for this research is based on how artists mix and print colour by traditional means (painting and printmaking) and how these differ from colour picker tools, slider bars and methods developed for digital printing, and whether it is possible to incorporate both? The paper provides a brief historical background to artists who have developed colour systems to assist their particular colour choices. Based on existing hardware and software, the paper suggests alternative approaches to colour selection, demonstrates methods for the creation of novel inkjet printed palettes, and how these can be visualised and compared.

  7. 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.

  8. Linguistic determinants of word colouring in grapheme-colour synaesthesia.

    PubMed

    Simner, Julia; Glover, Louise; Mowat, Alice

    2006-02-01

    Previous studies of grapheme-colour synaesthesia have suggested that words tend to be coloured by their initial letter or initial vowel (e.g., Baron-Cohen et al., 1993; Ward et al., 2005). We examine this assumption in two ways. First, we show that letter position and syllable stress have been confounded, such that the initial letters of a word are often in stressed position (e.g., 'wo-man, 'ta-ble, 'ha-ppy). With participant JW, we separate these factors (e.g., with stress homographs such as 'con-vict vs. con-'vict) and show that the primary determinant of word colour is syllable stress, with only a secondary influence of letter position. We show that this effect derives from conceptual rather than perceptual stress, and that the effect is more prominent for synaesthetes whose words are coloured by vowels than by consonants. We examine, too, the time course of word colour generation. Slower colour naming occurs for spoken versus written stimuli, as we might expect from the additional requirement of grapheme conversion in the former. Reaction time data provide evidence, too, of incremental processing, since word colour is generated faster when the dominant grapheme is flagged early rather than late in the spoken word. Finally, we examine the role of non-dominant graphemes in word colouring and show faster colour naming when later graphemes match the dominant grapheme (e.g., ether) compared to when they do not (e.g., ethos). Taken together, our findings suggest that words are coloured incrementally by a process of competition between constituent graphemes, in which stressed graphemes and word-initial graphemes are disproportionately weighted. PMID:16683502

  9. Demographic Variation between Colour Patterns in a Temperate Protogynous Hermaphrodite, the Ballan Wrasse Labrus bergylta

    PubMed Central

    Villegas-Ríos, David; Alonso-Fernández, Alexandre; Fabeiro, Mariña; Bañón, Rafael; Saborido-Rey, Fran

    2013-01-01

    Fish populations are often treated as homogeneous units in typical fishery management, thereby tacitly ignoring potential intraspecific variation which can lead to imprecise management rules. However, intraspecific variation in life-history traits is widespread and related to a variety of factors. We investigated the comparative age-based demography of the two main colour patterns of Labrus bergylta (plain and spotted, which coexist in sympatry), a commercially valuable resource in the NE Atlantic. Individuals were aged based on otolith readings after validating the annual periodicity of annuli deposition. The relationships between the otolith weight and fish age and between otolith length and fish length were strong but differed between colour patterns. The fit of the growth models to the age and length data resulted in divergent growth curves between colour morphotypes and between sexes. Males and spotted individuals attained larger mean asymptotic sizes (Linf) than females and plain individuals, respectively, but converged to them more slowly (smaller k). Estimates of mortality based on catch curves from two independent datasets provided a global total mortality (Z) of 0.35 yr–1, although Z was larger in plain and female individuals. Overall, the results of this research have direct implications for management of L. bergylta and, as a precautionary measure, we recommend considering both colour patterns as two different management units. PMID:24058404

  10. Why do seals have cones? Behavioural evidence for colour-blindness in harbour seals.

    PubMed

    Scholtyssek, Christine; Kelber, Almut; Dehnhardt, Guido

    2015-03-01

    All seals and cetaceans have lost at least one of two ancestral cone classes and should therefore be colour-blind. Nevertheless, earlier studies showed that these marine mammals can discriminate colours and a colour vision mechanism has been proposed which contrasts signals from cones and rods. However, these earlier studies underestimated the brightness discrimination abilities of these animals, so that they could have discriminated colours using brightness only. Using a psychophysical discrimination experiment, we showed that a harbour seal can solve a colour discrimination task by means of brightness discrimination alone. Performing a series of experiments in which two harbour seals had to discriminate the brightness of colours, we also found strong evidence for purely scotopic (rod-based) vision at light levels that lead to mesopic (rod-cone-based) vision in other mammals. This finding speaks against rod-cone-based colour vision in harbour seals. To test for colour-blindness, we used a cognitive approach involving a harbour seal trained to use a concept of same and different. We tested this seal with pairs of isoluminant stimuli that were either same or different in colour. If the seal had perceived colour, it would have responded to colour differences between stimuli. However, the seal responded with "same", providing strong evidence for colour-blindness.

  11. Are Korean Patients Different from Other Ethnic Groups in Total Knee Arthroplasty?

    PubMed

    Kim, Dong-Kyoon; Seo, Min-Chul; Song, Sang-Joon; Kim, Kang-Il

    2015-12-01

    Most of the implants used for total knee arthroplasty (TKA) in Asian patients have been produced based on anthropometry of Western people. Since anatomic features and life styles are different between Western and Eastern people, there would be ethnic differences in terms of conformity of implants to the patient's anatomy or clinical results after TKA. Therefore, surgeons in Asia are particularly interested in related surgical techniques and implant designs used in TKA for improved clinical results and patient satisfaction. In this review, we investigated the anthropometric differences of Koreans from Westerners. Koreans are of shorter stature, less weight, and smaller skeletal structure and have a higher incidence of constitutional varus alignment of the lower extremity. Moreover, compared to Westerner TKA populations, the proportion of female patients was large and primary osteoarthritis was prevalent in preoperative diagnosis in Korean TKA patients. Culturally, Koreans have life styles that demand high flexion positions of the knee such as squatting, kneeling, and cross-legged sitting. Although there were no notable differences in the complication and revision rates following TKA between Westerners and Koreans, the incidence of postoperative deep vein thrombosis and pulmonary thromboembolism was lower in Koreans than Westerners. We hope that further research on implant designs and more interest in TKA will improve outcomes in Korean patients.

  12. Are Korean Patients Different from Other Ethnic Groups in Total Knee Arthroplasty?

    PubMed Central

    Kim, Dong-Kyoon; Seo, Min-Chul; Song, Sang-Joon

    2015-01-01

    Most of the implants used for total knee arthroplasty (TKA) in Asian patients have been produced based on anthropometry of Western people. Since anatomic features and life styles are different between Western and Eastern people, there would be ethnic differences in terms of conformity of implants to the patient's anatomy or clinical results after TKA. Therefore, surgeons in Asia are particularly interested in related surgical techniques and implant designs used in TKA for improved clinical results and patient satisfaction. In this review, we investigated the anthropometric differences of Koreans from Westerners. Koreans are of shorter stature, less weight, and smaller skeletal structure and have a higher incidence of constitutional varus alignment of the lower extremity. Moreover, compared to Westerner TKA populations, the proportion of female patients was large and primary osteoarthritis was prevalent in preoperative diagnosis in Korean TKA patients. Culturally, Koreans have life styles that demand high flexion positions of the knee such as squatting, kneeling, and cross-legged sitting. Although there were no notable differences in the complication and revision rates following TKA between Westerners and Koreans, the incidence of postoperative deep vein thrombosis and pulmonary thromboembolism was lower in Koreans than Westerners. We hope that further research on implant designs and more interest in TKA will improve outcomes in Korean patients. PMID:26675374

  13. Colourful Semantics: A Clinical Investigation

    ERIC Educational Resources Information Center

    Bolderson, Sarah; Dosanjh, Christine; Milligan, Claudine; Pring, Tim; Chiat, Shula

    2011-01-01

    Children with language difficulties often omit verbs and grammatical elements and fail to complete sentences. Bryan (1997) described "colourful semantics", a therapy she used to treat a 5-year-old boy. The therapy uses colour coding to highlight the predicate argument structure of sentences. This study further tested the therapy's effectiveness by…

  14. Reversible colour change in Arthropoda.

    PubMed

    Umbers, Kate D L; Fabricant, Scott A; Gawryszewski, Felipe M; Seago, Ainsley E; Herberstein, Marie E

    2014-11-01

    The mechanisms and functions of reversible colour change in arthropods are highly diverse despite, or perhaps due to, the presence of an exoskeleton. Physiological colour changes, which have been recorded in 90 arthropod species, are rapid and are the result of changes in the positioning of microstructures or pigments, or in the refractive index of layers in the integument. By contrast, morphological colour changes, documented in 31 species, involve the anabolism or catabolism of components (e.g. pigments) directly related to the observable colour. In this review we highlight the diversity of mechanisms by which reversible colour change occurs and the evolutionary context and diversity of arthropod taxa in which it has been observed. Further, we discuss the functions of reversible colour change so far proposed, review the limited behavioural and ecological data, and argue that the field requires phylogenetically controlled approaches to understanding the evolution of reversible colour change. Finally, we encourage biologists to explore new model systems for colour change and to engage scientists from other disciplines; continued cross-disciplinary collaboration is the most promising approach to this nexus of biology, physics, and chemistry.

  15. The colour of gender stereotyping.

    PubMed

    Cunningham, Sheila J; Macrae, C Neil

    2011-08-01

    Despite legislative attempts to eliminate gender stereotyping from society, the propensity to evaluate people on the basis of their sex remains a pernicious social problem. Noting the critical interplay between cultural and cognitive factors in the establishment of stereotypical beliefs, the current investigation explored the extent to which culturally transmitted colour-gender associations (i.e., pink is for girls, blue is for boys) set the stage for the automatic activation and expression of gender stereotypes. Across six experiments, the results demonstrated that (1) consumer choice for children's goods is dominated by gender-stereotyped colours (Experiment 1); (2) colour-based stereotypic associations guide young children's behaviour (Experiment 2); (3) colour-gender associations automatically activate associated stereotypes in adulthood (Experiments 3-5); and (4) colour-based stereotypic associations bias impressions of male and female targets (Experiment 6). These findings indicate that, despite prohibitions against stereotyping, seemingly innocuous societal practices may continue to promote this mode of thought.

  16. Polarizational colours could help polarization-dependent colour vision systems to discriminate between shiny and matt surfaces, but cannot unambiguously code surface orientation.

    PubMed

    Hegedüs, Ramón; Horváth, Gábor

    2004-01-01

    It was hypothesized that egg-laying Papilio butterflies could use polarizational colours as a cue to detect leaf orientation and to discriminate between shiny and matt leaves. These hypotheses would be supported if the following general questions were answered positively: (1) Can surface orientation be unambiguously coded by the polarizational colours perceived by polarization-sensitive colour vision systems? (2) Are the changes in the polarizational colours due to retinal rotation significantly different between shiny and matt surfaces? Using video polarimetry, we measured the reflection-polarizational characteristics of a shiny green hemisphere in the red, green and blue spectral ranges for different solar elevations and directions of view with respect to the solar azimuth as well as for sunlit and shady circumstances under clear skies. The continuously curving hemisphere models numerous differently oriented surfaces. Using the polarization- and colour-sensitive retina model developed earlier, we computed the polarizational colours of the hemisphere, and investigated the correlation between colours and local surface orientation. We also calculated the maximal changes of the polarizational colours of shiny and matt hemispheres induced by rotation of the retina. We found that a surface with any orientation can possess almost any polarizational colour under any illumination condition. Consequently, polarizational colours cannot unambiguously code surface orientation. Polarization sensitivity is even disadvantageous for the detection of surface orientation by means of colours. On the other hand, the colour changes due to retinal rotation can be significantly larger for shiny surfaces than for matt ones. Thus, polarizational colours could help discrimination between shiny and matt surfaces. The physical and perceptional reasons for these findings are explained in detail. Our results and conclusions are of general importance for polarization-dependent colour vision

  17. Relationship between nine haloacetic acids with total organic halogens in different experimental conditions.

    PubMed

    Pourmoghadas, Hossein; Kinman, Riley N

    2013-04-03

    The effects of pH and bromide ion concentration on the formation of nine haloacetic acids (HAAs) and total organic halogens (TOX) in chlorinated drinking water have been evaluated. In an extensive study, the relationships of nine HAAs with TOX have been investigated. Honesty Significant Differences test (HSD) and ANOVA tests were used for the statistical analyses. The study determined the concentration range of nine HAAs as of a percentage of TOX at varying experimental conditions. Statistical analyses showed that the parameters pH and Br had significant effects on the formation of nine HAAs and TOX. This study also showed that brominated and mixed species of HAAs would be dominant in the presence of high bromide ion concentration which contributes a high percentage of the TOX. The results of this study could be used to set up a maximum contaminant level of TOX as a water quality standard for chlorination by-products.

  18. Patient-specific versus conventional instrumentation for total knee arthroplasty: peri-operative and cost differences.

    PubMed

    DeHaan, Alexander M; Adams, Jacob R; DeHart, Matthew L; Huff, Thomas W

    2014-11-01

    The role of patient-specific instrumentation in total knee arthroplasty (TKA) is yet to be clearly defined. Current evidence evaluating peri-operative and cost differences against conventional TKA is unclear. We reviewed 356 TKAs between July 2008 and April 2013; 306 TKAs used patient-specific instrumentation while 50 had conventional instrumentation. The patient-specific instrumentation cohort averaged 20.4 min less surgical time (P < 0.01) and had a 42% decrease in operating room turnover time (P = 0.022). At our institution, the money saved through increased operating room efficiency offset the cost of the custom cutting blocks and pre-operative advanced imaging. Routine use of patient-specific TKA can be performed with less surgical time, no increase in peri-operative morbidity, and at no increased cost when compared to conventional TKA.

  19. MAXIMUM NUMBER OF REPETITIONS, TOTAL WEIGHT LIFTED AND NEUROMUSCULAR FATIGUE IN INDIVIDUALS WITH DIFFERENT TRAINING BACKGROUNDS

    PubMed Central

    Azevedo, Neto R.M.; Julio, U.F.; Andreato, L.V.; Pinto e Silva, C.M.; Hardt, F.; Franchini, E.

    2013-01-01

    The aim of this study was to evaluate the performance, as well as neuromuscular activity, in a strength task in subjects with different training backgrounds. Participants (n = 26) were divided into three groups according to their training backgrounds (aerobic, strength or mixed) and submitted to three sessions: (1) determination of the maximum oxygen uptake during the incremental treadmill test to exhaustion and familiarization of the evaluation of maximum strength (1RM) for the half squat; (2) 1RM determination; and (3) strength exercise, four sets at 80% of the 1RM, in which the maximum number of repetitions (MNR), the total weight lifted (TWL), the root mean square (RMS) and median frequency (MF) of the electromyographic (EMG) activity for the second and last repetition were computed. There was an effect of group for MNR, with the aerobic group performing a higher MNR compared to the strength group (P = 0.045), and an effect on MF with a higher value in the second repetition than in the last repetition (P = 0.016). These results demonstrated that individuals with better aerobic fitness were more fatigue resistant than strength trained individuals. The absence of differences in EMG signals indicates that individuals with different training backgrounds have a similar pattern of motor unit recruitment during a resistance exercise performed until failure, and that the greater capacity to perform the MNR probably can be explained by peripheral adaptations. PMID:24744479

  20. [Characteristics of soil organic carbon and total nitrogen under different land use types in Shanghai].

    PubMed

    Shi, Li-jiang; Zheng, Li-bo; Mei, Xue-ying; Yu, Li-zhong; Jia, Zheng-chang

    2010-09-01

    By the methods of field sampling and laboratory analysis, this paper studied the variations of soil organic carbon (SOC) and total nitrogen (TN) contents and SOC density under different land use types in Shanghai. Significant differences were observed in the test parameters among different land use types. The SOC density was the highest in paddy field (3.86 kg x m(-2)), followed by in upland (3.17 kg x m(-2)), forestland (3.15 kg x m(-2)), abandoned land (2.73 kg x m(-2)), urban lawn (2.65 kg x m(-2)), garden land (2.13 kg x m(-2)), and tidal flat (1.38 kg x m(-2)). The assessment on the effects of three types of land use change on the test parameters showed that the conversion of paddy field into upland resulted in a significant decrease of SOC and TN contents and SOC density; the abandonment of farmland was not an effective way in improving SOC storage in the Yangtze Delta region with abundant water and heat resources, high soil fertility, and high level of field management; while the 4-5 years conversion of paddy field into artificial forestland decreased the SOC and TN contents and SOC density, suggesting that in a short term, the soil carbon sequestration effect of the conversion from paddy field to forestland was at a low level, due to the limitation of vegetation productivity.

  1. Human Milk MicroRNA and Total RNA Differ Depending on Milk Fractionation.

    PubMed

    Alsaweed, Mohammed; Hepworth, Anna R; Lefèvre, Christophe; Hartmann, Peter E; Geddes, Donna T; Hassiotou, Foteini

    2015-10-01

    MicroRNA have been recently discovered in human milk signifying potentially important functions for both the lactating breast and the infant. Whilst human milk microRNA have started to be explored, little data exist on the evaluation of sample processing, and analysis to ensure that a full spectrum of microRNA can be obtained. Human milk comprises three main fractions: cells, skim milk, and lipids. Typically, the skim milk fraction has been measured in isolation despite evidence that the lipid fraction may contain more microRNA. This study aimed to standardize isolation of microRNA and total RNA from all three fractions of human milk to determine the most appropriate sampling and analysis procedure for future studies. Three different methods from eight commercially available kits were tested for their efficacy in extracting total RNA and microRNA from the lipid, skim, and cell fractions of human milk. Each fraction yielded different concentrations of RNA and microRNA, with the highest quantities found in the cell and lipid fractions, and the lowest in skim milk. The column-based phenol-free method was the most efficient extraction method for all three milk fractions. Two microRNAs were expressed and validated in the three milk fractions by qPCR using the three recommended extraction kits for each fraction. High expression levels were identified in the skim and lipid milk factions for these microRNAs. These results suggest that careful consideration of both the human milk sample preparation and extraction protocols should be made prior to embarking upon research in this area.

  2. Human Milk MicroRNA and Total RNA Differ Depending on Milk Fractionation

    PubMed Central

    Alsaweed, Mohammed; Hepworth, Anna R.; Lefèvre, Christophe; Hartmann, Peter E.; Geddes, Donna T.

    2015-01-01

    ABSTRACT MicroRNA have been recently discovered in human milk signifying potentially important functions for both the lactating breast and the infant. Whilst human milk microRNA have started to be explored, little data exist on the evaluation of sample processing, and analysis to ensure that a full spectrum of microRNA can be obtained. Human milk comprises three main fractions: cells, skim milk, and lipids. Typically, the skim milk fraction has been measured in isolation despite evidence that the lipid fraction may contain more microRNA. This study aimed to standardize isolation of microRNA and total RNA from all three fractions of human milk to determine the most appropriate sampling and analysis procedure for future studies. Three different methods from eight commercially available kits were tested for their efficacy in extracting total RNA and microRNA from the lipid, skim, and cell fractions of human milk. Each fraction yielded different concentrations of RNA and microRNA, with the highest quantities found in the cell and lipid fractions, and the lowest in skim milk. The column‐based phenol‐free method was the most efficient extraction method for all three milk fractions. Two microRNAs were expressed and validated in the three milk fractions by qPCR using the three recommended extraction kits for each fraction. High expression levels were identified in the skim and lipid milk factions for these microRNAs. These results suggest that careful consideration of both the human milk sample preparation and extraction protocols should be made prior to embarking upon research in this area. J. Cell. Biochem. 116: 2397–2407, 2015. © 2015 The Authors. Journal of Cellular Biochemistry Published by Wiley Periodicals, Inc. PMID:25925799

  3. Lycopene content, antioxidant capacity and colour attributes of selected watermelon (Citrullus lanatus (Thunb.) Mansfeld) cultivars grown in India.

    PubMed

    Nagal, Shweta; Kaur, Charanjit; Choudhary, Harshawardhan; Singh, Jashbir; Bhushan Singh, Braj; Singh, K N

    2012-12-01

    The present investigation reports variability in lycopene, ascorbic acid, total phenolics, antioxidant capacity and colour attributes of 12 watermelon cultivars grown in India. Antioxidant capacity was evaluated using four in vitro assays, namely ferric reducing antioxidant power, cupric reducing antioxidant capacity, Trolox equivalent antioxidant capacity and 2,2-diphenyl-1-picryl hydrazyl. Among watermelon cultivars, significant differences (p < 0.05) were found with respect to lycopene content and antioxidant capacity. Lycopene content ranged from 03.46 to 8.00 mg/100 g fresh weight. Colour of watermelon flesh was described by an optimized colour index (CI). Cultivars 'PWM25-4', 'Arun', 'Kiran' and 'Kareena' were found to be the most promising ones with highest lycopene content, antioxidant capacity and CI. Results indicate that watermelon is a good source of dietary lycopene and there exists significant variation that can be exploited to produce high-quality cultivars.

  4. Corticosterone regulates multiple colour traits in Lacerta [Zootoca] vivipara males.

    PubMed

    San-Jose, L M; Fitze, P S

    2013-12-01

    Ornamental colours usually evolve as honest signals of quality, which is supported by the fact that they frequently depend on individual condition. It has generally been suggested that some, but not all types of ornamental colours are condition dependent, indicating that different evolutionary mechanisms underlie the evolution of multiple types of ornamental colours even when these are exhibited by the same species. Stress hormones, which negatively affect condition, have been shown to affect colour traits based on different pigments and structures, suggesting that they mediate condition dependence of multiple ornament types both among and within individuals. However, studies investigating effects of stress hormones on different ornament types within individuals are lacking, and thus, evidence for this hypothesis is scant. Here, we investigated whether corticosterone mediates condition dependence of multiple ornaments by manipulating corticosterone levels and body condition (via food availability) using a two-factorial design and by assessing their effect on multiple colour traits in male common lizards. Corticosterone negatively affected ventral melanin- and carotenoid-based coloration, whereas food availability did not affect coloration, despite its significant effect on body condition. The corticosterone effect on melanin- and carotenoid-based coloration demonstrates the condition dependence of both ornaments. Moreover, corticosterone affected ventral coloration and had no effect on the nonsexually selected dorsal coloration, showing specific effects of corticosterone on ornamental ventral colours. This suggests that corticosterone simultaneously mediates condition dependence of multiple colour traits and that it therefore accounts for covariation among them, which may influence their evolution via correlational selection.

  5. The phylogenetic significance of colour patterns in marine teleost larvae

    PubMed Central

    Baldwin, Carole C

    2013-01-01

    Ichthyologists, natural-history artists, and tropical-fish aquarists have described, illustrated, or photographed colour patterns in adult marine fishes for centuries, but colour patterns in marine fish larvae have largely been neglected. Yet the pelagic larval stages of many marine fishes exhibit subtle to striking, ephemeral patterns of chromatophores that warrant investigation into their potential taxonomic and phylogenetic significance. Colour patterns in larvae of over 200 species of marine teleosts, primarily from the western Caribbean, were examined from digital colour photographs, and their potential utility in elucidating evolutionary relationships at various taxonomic levels was assessed. Larvae of relatively few basal marine teleosts exhibit erythrophores, xanthophores, or iridophores (i.e. nonmelanistic chromatophores), but one or more of those types of chromatophores are visible in larvae of many basal marine neoteleosts and nearly all marine percomorphs. Whether or not the presence of nonmelanistic chromatophores in pelagic marine larvae diagnoses any major teleost taxonomic group cannot be determined based on the preliminary survey conducted, but there is a trend toward increased colour from elopomorphs to percomorphs. Within percomorphs, patterns of nonmelanistic chromatophores may help resolve or contribute evidence to existing hypotheses of relationships at multiple levels of classification. Mugilid and some beloniform larvae share a unique ontogenetic transformation of colour pattern that lends support to the hypothesis of a close relationship between them. Larvae of some tetraodontiforms and lophiiforms are strikingly similar in having the trunk enclosed in an inflated sac covered with xanthophores, a character that may help resolve the relationships of these enigmatic taxa. Colour patterns in percomorph larvae also appear to diagnose certain groups at the interfamilial, familial, intergeneric, and generic levels. Slight differences in generic

  6. The phylogenetic significance of colour patterns in marine teleost larvae.

    PubMed

    Baldwin, Carole C

    2013-07-01

    Ichthyologists, natural-history artists, and tropical-fish aquarists have described, illustrated, or photographed colour patterns in adult marine fishes for centuries, but colour patterns in marine fish larvae have largely been neglected. Yet the pelagic larval stages of many marine fishes exhibit subtle to striking, ephemeral patterns of chromatophores that warrant investigation into their potential taxonomic and phylogenetic significance. Colour patterns in larvae of over 200 species of marine teleosts, primarily from the western Caribbean, were examined from digital colour photographs, and their potential utility in elucidating evolutionary relationships at various taxonomic levels was assessed. Larvae of relatively few basal marine teleosts exhibit erythrophores, xanthophores, or iridophores (i.e. nonmelanistic chromatophores), but one or more of those types of chromatophores are visible in larvae of many basal marine neoteleosts and nearly all marine percomorphs. Whether or not the presence of nonmelanistic chromatophores in pelagic marine larvae diagnoses any major teleost taxonomic group cannot be determined based on the preliminary survey conducted, but there is a trend toward increased colour from elopomorphs to percomorphs. Within percomorphs, patterns of nonmelanistic chromatophores may help resolve or contribute evidence to existing hypotheses of relationships at multiple levels of classification. Mugilid and some beloniform larvae share a unique ontogenetic transformation of colour pattern that lends support to the hypothesis of a close relationship between them. Larvae of some tetraodontiforms and lophiiforms are strikingly similar in having the trunk enclosed in an inflated sac covered with xanthophores, a character that may help resolve the relationships of these enigmatic taxa. Colour patterns in percomorph larvae also appear to diagnose certain groups at the interfamilial, familial, intergeneric, and generic levels. Slight differences in generic

  7. Mixing of components from different manufacturers in total hip arthroplasty: prevalence and comparative outcomes

    PubMed Central

    Tucker, Keith; Pickford, Martin; Newell, Claire; Howard, Peter; Hunt, Linda P; Blom, Ashley W

    2015-01-01

    Background and purpose — There have recently been highly publicized examples of suboptimal outcomes with some newer implant designs used for total hip replacement. This has led to calls for tighter regulation. However, surgeons do not always adhere to the regulations already in place and often use implants from different manufacturers together to replace a hip, which is against the recommendations of the Medicines and Healthcare Products Regulatory Agency (MHRA) and the directions of the manufacturers. Patients and methods — We used data from the National Joint Registry of England and Wales (NJR) to investigate this practice. Results — Mixing of components was common, and we identified over 90,000 cases recorded between 2003 and 2013. In the majority of these cases (48,156), stems and heads from one manufacturer were mixed with polyethylene cemented cups from another manufacturer. When using a cemented stem and a polyethylene cup, mixing of stems from one manufacturer with cups from another was associated with a lower revision rate. At 8 years, the cumulative percentage of revisions was 1.9% (95% CI: 1.7–2.1) in the mixed group as compared to 2.4% (2.3–2.5) in the matched group (p = 0.001). Mixing of heads from one manufacturer with stems from another was associated with a higher revision rate (p < 0.001). In hip replacements with ceramic-on-ceramic or metal-on-metal bearings, mixing of stems, heads, and cups from different manufacturers was associated with similar revision rates (p > 0.05). Interpretation — Mixing of components from different manufacturers is a common practice, despite the fact that it goes against regulatory guidance. However, it is not associated with increased revision rates unless heads and stems from different manufacturers are used together. PMID:26201845

  8. TDS exposure project: relevance of the total diet study approach for different groups of substances.

    PubMed

    Vin, Karine; Papadopoulos, Alexandra; Cubadda, Francesco; Aureli, Federica; Oktay Basegmez, Hatice Imge; D'Amato, Marilena; De Coster, Sam; D'Evoli, Laura; López Esteban, María Teresa; Jurkovic, Martina; Lucarini, Massimo; Ozer, Hayrettin; Fernández San Juan, Pedro Mario; Sioen, Isabelle; Sokolic, Darja; Turrini, Aida; Sirot, Véronique

    2014-11-01

    A method to validate the relevance of the Total Diet Study (TDS) approach for different types of substances is described. As a first step, a list of >2800 chemicals classified into eight main groups of relevance for food safety (natural components, environmental contaminants, substances intentionally added to foods, residues, naturally occurring contaminants, process contaminants, contaminants from packaging and food contact materials, other substances) has been established. The appropriateness of the TDS approach for the different substance groups has then been considered with regard to the three essential principles of a TDS: representativeness of the whole diet, pooling of foods and food analyzed as consumed. Four criteria were considered for that purpose (i) the substance has to be present in a significant part of the diet or predominantly present in specific food groups, (ii) a robust analytical method has to be available to determine it in potential contributors to the dietary exposure of the population, and (iii) the dilution impact of pooling and (iv) the impact of everyday food preparation methods on the concentration of the substance are assessed. For most of the substances the TDS approach appeared to be relevant and any precautions to be taken are outlined.

  9. Clinical and Biomechanical Evaluations of Staged Bilateral Total Knee Arthroplasty Patients with Two Different Implant Designs

    PubMed Central

    Renaud, Alexandre; Fuentes, Alexandre; Hagemeister, Nicola; Lavigne, Martin; Vendittoli, Pascal-André

    2016-01-01

    Background: Various implants of total knee arthroplasty (TKA) are used in clinical practice and each presents specific design characteristics. No implant managed this day to reproduce perfectly the biomechanics of the natural knee during gait. Objectives: We therefore asked whether (1) differences in tridimensional (3D) kinematic data during gait could be observed in two different designs of TKA on the same patients, (2) if those gait kinematic data are comparable with those of asymptomatic knees and (3) if difference in clinical subjective scores can be observed between the two TKA designs on the same patient. Methods: We performed knee kinematic analysis on 15 patients (30 TKAs) with two different TKA implant designs (Nexgen, Zimmer and Triathlon, Stryker) on each knee and on 25 asymptomatic subjects (35 knees). Clinical evaluation included range of motion, weight bearing radiographs, questionnaire of joint perception, KOOS, WOMAC and SF-12. Results: Comparison between TKAs and asymptomatic knees revealed that asymptomatic knees had significantly less knee flexion at initial contact (p < 0.04) and more flexion for most of the swing phase (p between 0.004 and 0.04). Asymptomatic knees also had less varus at loading response, during stance phase and during most of the swing phase (p between 0.001 - 0.05). Transverse plane analysis showed a tendency for asymptomatic knees to be more in internal rotation during stance phase (p 0.02 - 0.04). Comparing both TKA designs, NexgenTM implant had significantly more flexion at the end of swing phase (p = 0.04) compared to knees with the TriathlonTM implant. In frontal plane, from initial contact to maximum mid stance angle and between the mean mid stance angle and initial contact NexgenTM TKA had significantly more adduction (varus, p =0.02 – 0.03). Clinical scores of both TKAs did not have significant difference. Conclusions: TKA with the tested implants did not reproduce natural knee kinematics during gait. In our cohort

  10. Colour categorization by domestic chicks.

    PubMed

    Jones, C D; Osorio, D; Baddeley, R J

    2001-10-22

    Spectral stimuli form a physical continuum, which humans divide into discrete non-overlapping regions or categories that are designated by colour names. Little is known about whether non-verbal animals form categories on stimulus continua, but work in psychology and artificial intelligence provides models for stimulus generalization and categorization. We compare predictions of such models to the way poultry chicks (Gallus gallus) generalize to novel stimuli following appetitive training to either one or two colours. If the two training colours are (to human eyes) red and greenish-yellow or green and blue, chicks prefer intermediates, i.e. orange rather than red or yellow and turquoise rather than green or blue. The level of preference for intermediate colours implies that the chicks interpolate between the training stimuli. However, they do not extrapolate beyond the limits set by the training stimuli, at least for red and yellow training colours. Similarly, chicks trained to red and blue generalize to purple, but they do not generalize across grey after training to the complementary colours yellow and blue. These results are consistent with a modified version of a Bayesian model of generalization from multiple examples that was proposed by Shepard and show similarities to human colour categorization.

  11. Colour thresholding in video imaging.

    PubMed Central

    Fermin, C D; Degraw, S

    1995-01-01

    The basic aspects of video imaging are reviewed as they relate to measurements of histological and anatomical features, with particular emphasis on the advantages and disadvantages of colour and black-and-white imaging modes. In black-and-white imaging, calculations are based on the manipulation of picture elements (pixels) that contain 0-255 levels of information. Black is represented by the absence of light (0) and white by 255 grades of light. In colour imaging, the pixels contain variation of hues for the primary (red, green and blue) and secondary (magenta, yellow, cyan, pink) colours. Manipulation of pixels with colour information is more computer intense than that for black-and-white pixels, because there are over 16 million possible combinations of colour in a system with a 24-bit resolution. The narrow 128 possible grades of separation in black and white often makes distinction between pixels with overlapping intensities difficult. Such difficulty is greatly reduced by colour thresholding of systems that base the representation of colour on a combination of hue-saturation-intensity (HSI) format. Images Fig. 3 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 Fig. 10 Fig. 11 Fig. 12 Fig. 13 Fig. 14 Fig. 15 Fig. 16 Fig. 17 Fig. 18 Fig. 19 Fig. 20 PMID:7559121

  12. Influence of Texture and Colour in Breast TMA Classification

    PubMed Central

    Fernández-Carrobles, M. Milagro; Bueno, Gloria; Déniz, Oscar; Salido, Jesús; García-Rojo, Marcial; González-López, Lucía

    2015-01-01

    Breast cancer diagnosis is still done by observation of biopsies under the microscope. The development of automated methods for breast TMA classification would reduce diagnostic time. This paper is a step towards the solution for this problem and shows a complete study of breast TMA classification based on colour models and texture descriptors. The TMA images were divided into four classes: i) benign stromal tissue with cellularity, ii) adipose tissue, iii) benign and benign anomalous structures, and iv) ductal and lobular carcinomas. A relevant set of features was obtained on eight different colour models from first and second order Haralick statistical descriptors obtained from the intensity image, Fourier, Wavelets, Multiresolution Gabor, M-LBP and textons descriptors. Furthermore, four types of classification experiments were performed using six different classifiers: (1) classification per colour model individually, (2) classification by combination of colour models, (3) classification by combination of colour models and descriptors, and (4) classification by combination of colour models and descriptors with a previous feature set reduction. The best result shows an average of 99.05% accuracy and 98.34% positive predictive value. These results have been obtained by means of a bagging tree classifier with combination of six colour models and the use of 1719 non-correlated (correlation threshold of 97%) textural features based on Statistical, M-LBP, Gabor and Spatial textons descriptors. PMID:26513238

  13. Colour learning when foraging for nectar and pollen: bees learn two colours at once.

    PubMed

    Muth, Felicity; Papaj, Daniel R; Leonard, Anne S

    2015-09-01

    Bees are model organisms for the study of learning and memory, yet nearly all such research to date has used a single reward, nectar. Many bees collect both nectar (carbohydrates) and pollen (protein) on a single foraging bout, sometimes from different plant species. We tested whether individual bumblebees could learn colour associations with nectar and pollen rewards simultaneously in a foraging scenario where one floral type offered only nectar and the other only pollen. We found that bees readily learned multiple reward-colour associations, and when presented with novel floral targets generalized to colours similar to those trained for each reward type. These results expand the ecological significance of work on bee learning and raise new questions regarding the cognitive ecology of pollination.

  14. Colour Changes on the Surface of the Rock Materials Due to UV-A and UV-B Rays

    NASA Astrophysics Data System (ADS)

    Binal, Adil; Ayderman, Aykut; Sel, Aylin

    2015-04-01

    The colour of the rocks used in the current buildings, and historical monuments is an important parameter in architecture and engineering. In addition, engineering geologists use the colour in order to identify the weathering class of rock material. The main colour of the stone, especially, are affected by the mineral size, the colour of the primary minerals and matrix material, as well as the colour of the accessory minerals. Due to atmospheric effects, changes in the outer surface colour of the rocks used as siding materials occur with over time. Factors causing the colour change are carbon dioxide (CO2), ozone (O3), sulphate (SO2, SO3) and nitrate (NOx) from the atmosphere with aerosols as well as UV rays from the sun. There is no more work in the literature on colour changes caused by UV-A and UV-B rays. In this study, the effects of ultraviolet in the colour of the surfaces of basalt, limestone, ignimbrite, travertine and sandstone have been simulated with a new experimental device in the laboratory medium. Lutron colour analyser (RGB-1002) was used for the measurements of RGB colours. Colour differences between the beginning and end of tests were determined with the standard practice for calculation of colour tolerances and colour differences from instrumentally measured colour coordinates (ASTM D2244). As a result of the experiments performed, lighten that seem on dark-grey micritic limestone (colour change ratio, CCR: 17.06) and basalt samples (CCR: 8.24) become even visually noticeable. Black and red ignimbrite samples having high porosity were presented the lower rate of colour changes. Finally, colour darkening has been observed in the light-coloured travertine (CCR: 13.8) and sandstone samples (CCR: 20.99).

  15. Quantitative studies of animal colour constancy: using the chicken as model.

    PubMed

    Olsson, Peter; Wilby, David; Kelber, Almut

    2016-05-11

    Colour constancy is the capacity of visual systems to keep colour perception constant despite changes in the illumination spectrum. Colour constancy has been tested extensively in humans and has also been described in many animals. In humans, colour constancy is often studied quantitatively, but besides humans, this has only been done for the goldfish and the honeybee. In this study, we quantified colour constancy in the chicken by training the birds in a colour discrimination task and testing them in changed illumination spectra to find the largest illumination change in which they were able to remain colour-constant. We used the receptor noise limited model for animal colour vision to quantify the illumination changes, and found that colour constancy performance depended on the difference between the colours used in the discrimination task, the training procedure and the time the chickens were allowed to adapt to a new illumination before making a choice. We analysed literature data on goldfish and honeybee colour constancy with the same method and found that chickens can compensate for larger illumination changes than both. We suggest that future studies on colour constancy in non-human animals could use a similar approach to allow for comparison between species and populations. PMID:27170714

  16. Quantitative studies of animal colour constancy: using the chicken as model.

    PubMed

    Olsson, Peter; Wilby, David; Kelber, Almut

    2016-05-11

    Colour constancy is the capacity of visual systems to keep colour perception constant despite changes in the illumination spectrum. Colour constancy has been tested extensively in humans and has also been described in many animals. In humans, colour constancy is often studied quantitatively, but besides humans, this has only been done for the goldfish and the honeybee. In this study, we quantified colour constancy in the chicken by training the birds in a colour discrimination task and testing them in changed illumination spectra to find the largest illumination change in which they were able to remain colour-constant. We used the receptor noise limited model for animal colour vision to quantify the illumination changes, and found that colour constancy performance depended on the difference between the colours used in the discrimination task, the training procedure and the time the chickens were allowed to adapt to a new illumination before making a choice. We analysed literature data on goldfish and honeybee colour constancy with the same method and found that chickens can compensate for larger illumination changes than both. We suggest that future studies on colour constancy in non-human animals could use a similar approach to allow for comparison between species and populations.

  17. Colour stability of maxillofacial silicone elastomers: a review of the literature.

    PubMed

    Kulkarni, R S; Nagda, S J

    2014-09-01

    Colour degradation is a serious limitation of maxillofacial silicone elastomers and most silicone facial prostheses have to be remade within 1 year due to colour deterioration. A comprehensive review of the literature was completed using MEDLINE and PubMed Library databases. This was supplemented with a manual search of selected journals and textbooks. English language articles published in peer-reviewed journals from 1966 to January 2012 in which colour stability of silicone elastomers was evaluated using standard research protocols were included. In all, 127 articles were identified and 23 met the inclusion criteria. Current literature reveals that average colour stability of maxillofacial silicone prostheses is 6-12 months, and inherent unstable nature of silicones is responsible for the color degradation. Opacifiers, oil pigments and inorganic colourants may have a protective effect on colour stability of prostheses. Organic colourants, ultraviolet (UV) light, cleansing solutions, dust and aging can adversely affect colour stability of silicone prostheses. A direct comparison between studies has not been possible, because of the differences in experimental set-up such as materials tested, colourants used, or method of aging. There appears to be a need for a standardised test protocol for colour stability of maxillofacial materials. Colour degradation limits the useful lifespan of maxillofacial silicones. Improvements in colour stability is possible with the use of certain nano opacifiers, UV absorbers, photoprotective agents, and use of inorganic pigments and metal oxides.

  18. Pulsed electric field improves the bioprotective capacity of purées for different coloured carrot cultivars against H2O2-induced oxidative damage.

    PubMed

    Leong, Sze Ying; Oey, Indrawati; Burritt, David John

    2016-04-01

    This research aimed to study the effect of pulsed electric field (PEF) processing on the bioprotective capacity of carrot purée for White Belgian, Yellow Solar, Nantes, Nutri Red and Purple Haze cultivars against H2O2-induced oxidative damage. The bioprotective capacity was determined using cell viability, membrane integrity and nitric oxide (NO) production in a human Caco-2 cell culture assay. Total carotenoids, total anthocyanins, total vitamin C and total phenolics were also evaluated. Compared to the untreated purée, Purple Haze and Nutri Red processed at 303 kJ/kg completely increased Caco-2 cells resistance towards oxidative damage by recovering the cell viability and inhibiting NO production. For cultivar with low carotenoid levels, i.e. Yellow Solar, the application of 0.8 kV/cm resulted in a higher total carotenoid content in the purée than its untreated counterpart, leading to an improved bioprotective effect. This study clearly shows that PEF could add value to carrots by maximising bioprotective effects. PMID:26593539

  19. Colour anomia resulting from weakened short-term colour memory. A case study.

    PubMed

    Davidoff, J B; Ostergaard, A L

    1984-06-01

    A patient exhibited marked colour anomia without object anomia, but was able to point to named colours. Five experiments were conducted to investigate his immediate colour memory. It was concluded that his colour anomia was the result of an impaired short-term memory deficit specific to colour. Temporary activation of specific entries in the colour lexicon enabled pointing and even naming to take place. A general model incorporating all forms of colour anomia is presented.

  20. Opening up a Colourful Cosmic Jewel Box

    NASA Astrophysics Data System (ADS)

    2009-10-01

    and exquisite image quality have resulted in a brand-new, very sharp view despite a total exposure time of just 5 seconds. This new image is one of the best ever taken of this cluster from the ground. The Jewel Box may be visually colourful in images taken on Earth, but observing from space allows the NASA/ESA Hubble Space Telescope to capture light of shorter wavelengths than can not be seen by telescopes on the ground. This new Hubble image of the core of the cluster represents the first comprehensive far ultraviolet to near-infrared image of an open galactic cluster. It was created from images taken through seven filters, allowing viewers to see details never seen before. It was taken near the end of the long life of the Wide Field Planetary Camera 2 ― Hubble's workhorse camera up until the recent Servicing Mission, when it was removed and brought back to Earth. Several very bright, pale blue supergiant stars, a solitary ruby-red supergiant and a variety of other brilliantly coloured stars are visible in the Hubble image, as well as many much fainter ones. The intriguing colours of many of the stars result from their differing intensities at different ultraviolet wavelengths. The huge variety in brightness of the stars in the cluster exists because the brighter stars are 15 to 20 times the mass of the Sun, while the dimmest stars in the Hubble image are less than half the mass of the Sun. More massive stars shine much more brilliantly. They also age faster and make the transition to giant stars much more quickly than their faint, less-massive siblings. The Jewel Box cluster is about 6400 light-years away and is approximately 16 million years old. Notes [1] Open, or galactic, star clusters are not to be confused with globular clusters ― huge balls of tens of thousands of ancient stars in orbit around our galaxy and others. It seems that most stars, including our Sun, formed in open clusters. [2] The Coal Sack is a dark nebula in the Southern Hemisphere, near the

  1. The contribution of structural-, psittacofulvin- and melanin-based colouration to sexual dichromatism in Australasian parrots.

    PubMed

    Taysom, A J; Stuart-Fox, D; Cardoso, G C

    2011-02-01

    Colour ornamentation in animals is exceptionally diverse, but some colours may provide better signals of individual quality or more efficient visual stimuli and, thus, be more often used as sexual signals. This may depend on physiological costs, which depend on the mechanism of colour production (e.g. exogenously acquired colouration in passerine birds appears to be most sexually dichromatic). We studied sexual dichromatism in a sample of 27 Australasian parrot species with pigment- (melanin and psittacofulvin) and structural-based colouration, to test whether some of these types of colouration are more prominent in sexual ornamentation. Unlike passerines, in which long wavelength colouration (yellow to red) usually involves exogenous and costly carotenoid pigments, yellow to red colouration in parrots is based on endogenously synthesized psittacofulvin pigments. This allows us to assess whether costly exogenous pigments are necessary for these plumage colours to have a prominent role in sexual signalling. Structural blue colouration showed the largest and most consistent sexual dichromatism, both in area and perceptually relevant chromatic differences, indicating that it is often ornamental in parrots. By contrast, we found little evidence for consistent sexual dichromatism in melanin-based colouration. Unlike passerines, yellow to red colouration was not strongly sexually dichromatic: although the area of colouration was generally larger in males, colour differences between the sexes were on average imperceptible to parrots. This is consistent with the idea that the prominent yellow to red sexual dichromatism in passerines is related to the use of carotenoid pigments, rather than resulting from sensory bias for these colours.

  2. The Attenborough total knee prosthesis. Results of 25 operations evaluated according to two different assessment systems.

    PubMed

    Kofoed, H

    1981-10-01

    The Attenborough stabilized gliding total knee prosthesis was used in cases of severely damaged, highly unstable or deformed knees. Twenty-five operated cases were followed for 1 1/2 years (range 12-28 months). The results were assessed according to two different knee evaluation systems: The Lotke & Ecker knee evaluation index and the knee function assessment chart (BOA chart) suggested by the British Orthopaedic Association. The overall results were excellent or good in 84 per cent (21/25) of the cases according to both systems, but when considering the improvement in individual clinical features the BOA chart results were more optimistic. Neither of the systems takes into consideration that the results are influenced by possible disorders in other joints. If only the function of the knees was being judged the results of the operations with the Attenborough prosthesis were excellent or good in 96 per cent (24/25) in this series. In general the results to be as good as those obtained in less disabled knees treated with compartmental prostheses. As more extensive surgery and bone resection is needed for insertion of the Attenborough prosthesis compared with compartmental prostheses, its use should be restricted to severely damaged knees which would otherwise be treated with a hinged prosthesis or an arthrodesis.

  3. Friction of total hip replacements with different bearings and loading conditions.

    PubMed

    Brockett, Claire; Williams, Sophie; Jin, Zhongmin; Isaac, Graham; Fisher, John

    2007-05-01

    Metal-on-ultra-high molecular weight polyethylene (UHMWPE) total hip replacements have been the most popular and clinically successful implants to date. However, it is well documented that the wear debris from these prostheses contributes to osteolysis and ultimate failure of the prosthesis, hence alternative materials have been sought. A range of 28 mm diameter bearings were investigated using a hip friction simulator, including conventional material combinations such as metal-on-UHWMPE, ceramic-on-ceramic (CoC), and metal-on-metal (MoM), as well as novel ceramic-on-metal (CoM) pairings. Studies were performed under different swing-phase load and lubricant conditions. The friction factors were lowest in the ceramic bearings, with the CoC bearing having the lowest friction factor in all conditions. CoM bearings also had low friction factors compared with MoM, and the trends were similar to CoC bearings for all test conditions. Increasing swing phase load was shown to cause an increase in friction factor in all tests. Increased serum concentration resulted in increased friction factor in all material combinations, except MoM, where increased serum concentration produced a significant reduction in friction factor.

  4. Species differences in total mercury concentration in gulls from the Gulf of Gdansk (Southern Baltic).

    PubMed

    Szumiło-Pilarska, Emilia; Grajewska, Agnieszka; Falkowska, Lucyna; Hajdrych, Julia; Meissner, Włodzimierz; Frączek, Tomasz; Bełdowska, Magdalena; Bzoma, Szymon

    2016-01-01

    Aquatic birds occupy a high position in the trophic pyramid of the Baltic Sea. This means that they accumulate the greatest amount of harmful substances, including mercury, in their bodies. This element penetrates into their systems mainly via the alimentary canal. The amount of mercury absorbed from food depends on how badly the environment is polluted with this metal. The aim of this study was to discover the concentrations of total mercury (HgT) in the contour feathers, muscles, brain, lungs, liver, kidneys, heart and blood of four gull species Herring Gull (Larus argentatus), Common Gull (Larus canus), Black-headed Gull (Larus ridibundus) and Great Black-backed Gull (Larus marinus) and organic mercury (Hgorg) in the liver and brain of Herring Gull. The most important characteristic of the results obtained for the studied gulls was the statistically significant differences between the four species, probably resulting from their different diets-confirmed by stable-isotopes analysis (δ(15)N and δ(13)C). A logarithmic dependence was found between HgT in the blood and HgT in the brain of the Herring Gull. The authors suggest that among gulls burdened with the greatest mercury load, it is possible that the brain is protected by higher Hg accumulation in the muscles. The percentage share of Hgorg in the brain and liver of the Herring Gull depended on the concentration of HgT in these tissues and was always higher in the brain. In none of the cases, did the mercury levels assayed in the internal gulls' tissues exceed values associated with adverse health effects.

  5. Species differences in total mercury concentration in gulls from the Gulf of Gdansk (Southern Baltic).

    PubMed

    Szumiło-Pilarska, Emilia; Grajewska, Agnieszka; Falkowska, Lucyna; Hajdrych, Julia; Meissner, Włodzimierz; Frączek, Tomasz; Bełdowska, Magdalena; Bzoma, Szymon

    2016-01-01

    Aquatic birds occupy a high position in the trophic pyramid of the Baltic Sea. This means that they accumulate the greatest amount of harmful substances, including mercury, in their bodies. This element penetrates into their systems mainly via the alimentary canal. The amount of mercury absorbed from food depends on how badly the environment is polluted with this metal. The aim of this study was to discover the concentrations of total mercury (HgT) in the contour feathers, muscles, brain, lungs, liver, kidneys, heart and blood of four gull species Herring Gull (Larus argentatus), Common Gull (Larus canus), Black-headed Gull (Larus ridibundus) and Great Black-backed Gull (Larus marinus) and organic mercury (Hgorg) in the liver and brain of Herring Gull. The most important characteristic of the results obtained for the studied gulls was the statistically significant differences between the four species, probably resulting from their different diets-confirmed by stable-isotopes analysis (δ(15)N and δ(13)C). A logarithmic dependence was found between HgT in the blood and HgT in the brain of the Herring Gull. The authors suggest that among gulls burdened with the greatest mercury load, it is possible that the brain is protected by higher Hg accumulation in the muscles. The percentage share of Hgorg in the brain and liver of the Herring Gull depended on the concentration of HgT in these tissues and was always higher in the brain. In none of the cases, did the mercury levels assayed in the internal gulls' tissues exceed values associated with adverse health effects. PMID:26653750

  6. Energy Inputs Uncertainty: Total Amount, Distribution and Correlation Between Different Forms of Energy

    NASA Technical Reports Server (NTRS)

    Deng, Yue

    2014-01-01

    Describes solar energy inputs contributing to ionospheric and thermospheric weather processes, including total energy amounts, distributions and the correlation between particle precipitation and Poynting flux.

  7. The role of pollinators in maintaining variation in flower colour in the Rocky Mountain columbine, Aquilegia coerulea

    PubMed Central

    Thairu, Margaret W.; Brunet, Johanne

    2015-01-01

    Background and Aims Flower colour varies within and among populations of the Rocky Mountain columbine, Aquilegia coerulea, in conjunction with the abundance of its two major pollinators, hawkmoths and bumble-bees. This study seeks to understand whether the choice of flower colour by these major pollinators can help explain the variation in flower colour observed in A. coerulea populations. Methods Dual choice assays and experimental arrays of blue and white flowers were used to determine the preference of hawkmoths and bumble-bees for flower colour. A test was made to determine whether a differential preference for flower colour, with bumble-bees preferring blue and hawkmoths white flowers, could explain the variation in flower colour. Whether a single pollinator could maintain a flower colour polymorphism was examined by testing to see if preference for a flower colour varied between day and dusk for hawkmoths and whether bumble-bees preferred novel or rare flower colour morphs. Key Results Hawkmoths preferred blue flowers under both day and dusk light conditions. Naïve bumble-bees preferred blue flowers but quickly learned to forage randomly on the two colour morphs when similar rewards were presented in the flowers. Bees quickly learned to associate a flower colour with a pollen reward. Prior experience affected the choice of flower colour by bees, but they did not preferentially visit novel flower colours or rare or common colour morphs. Conclusions Differences in flower colour preference between the two major pollinators could not explain the variation in flower colour observed in A. coerulea. The preference of hawkmoths for flower colour did not change between day and dusk, and bumble-bees did not prefer a novel or a rare flower colour morph. The data therefore suggest that factors other than pollinators may be more likely to affect the flower colour variation observed in A. coerulea. PMID:25808657

  8. Colour constancy across the life span: evidence for compensatory mechanisms.

    PubMed

    Wuerger, Sophie

    2013-01-01

    It is well known that the peripheral visual system declines with age: the yellowing of the lens causes a selective reduction of short-wavelength light and sensitivity losses occur in the cone receptor mechanisms. At the same time, our subjective experience of colour does not change with age. The main purpose of this large-scale study (n = 185) covering a wide age range of colour-normal observers (18-75 years of age) was to assess the extent to which the human visual system is able to compensate for the changes in the optical media and at which level of processing this compensation is likely to occur. We report two main results: (1) Supra-threshold parafoveal colour perception remains largely unaffected by the age-related changes in the optical media (yellowing of the lens) whereas our ability to discriminate between small colour differences is compromised with an increase in age. (2) Significant changes in colour appearance are only found for unique green settings under daylight viewing condition which is consistent with the idea that the yellow-blue mechanism is most affected by an increase in age due to selective attenuation of short-wavelength light. The data on the invariance of hue perception, in conjunction with the age-related decline in chromatic sensitivity, provides evidence for compensatory mechanisms that enable colour-normal human observers a large degree of colour constancy across the life span. These compensatory mechanisms are likely to originate at cortical sites.

  9. Optoelectronics: Colour-selective photodiodes

    NASA Astrophysics Data System (ADS)

    Johnston, Michael B.

    2015-10-01

    Perovskite semiconductors have altered the landscape of solar cell research. Now researchers show that these materials may also offer a flexible platform for colour imaging and wavelength-selective sensing.

  10. A universal ultraviolet-optical colour-colour-magnitude relation of galaxies

    NASA Astrophysics Data System (ADS)

    Chilingarian, Igor V.; Zolotukhin, Ivan Yu.

    2012-01-01

    The bimodal galaxy distribution in the optical colour-magnitude diagram (CMD) comprises a narrow 'red sequence' populated mostly by early-type galaxies and a broad 'blue cloud' dominated by star-forming systems. Although the optical CMD allows one to select red sequence objects, neither can it be used for galaxy classification without additional observational data such as spectra or high-resolution images, nor to identify blue galaxies at unknown redshifts. We show that adding the near ultraviolet (NUV) colour [Galaxy Evolution Explorer (GALEX) NUV λeff= 227 nm] to the optical (g - r versus Mr) CMD reveals a tight relation in the 3D colour-colour-magnitude space smoothly continuing from the 'blue cloud' to the 'red sequence'. We found that 98 per cent of 225 000 low-redshift (Z < 0.27) galaxies follow a smooth surface ? with a standard deviation of 0.03-0.07 mag making it the tightest known galaxy photometric relation, given the ˜0.9 mag range of k-corrected g - r colours. Similar relations exist in other NUV-optical colours. There is a strong correlation between morphological types and integrated ? colours of galaxies, while the connection with g - r is ambiguous. Rare galaxy classes such as E+A or tidally stripped systems become outliers that occupy distinct regions in the 3D parameter space. Using stellar population models for galaxies with different star formation histories, we show that (a) the (?) distribution at a given luminosity is formed by objects having constant and exponentially declining star formation rates with different characteristic time-scales with the red sequence part consistent also with simple stellar population; (b) colour evolution for exponentially declining models goes along the relation suggesting a weak evolution of its shape up to a redshift of 0.9; (c) galaxies with truncated star formation histories have very short transition phase offset from the relation thus explaining the rareness of E+A galaxies. This relation can be used as

  11. How to Calculate Colourful Cross Sections Efficiently

    SciTech Connect

    Gleisberg, Tanju; Hoeche, Stefan; Krauss, Frank

    2008-09-03

    Different methods for the calculation of cross sections with many QCD particles are compared. To this end, CSW vertex rules, Berends-Giele recursion and Feynman-diagram based techniques are implemented as well as various methods for the treatment of colours and phase space integration. We find that typically there is only a small window of jet multiplicities, where the CSW technique has efficiencies comparable or better than both of the other two methods.

  12. What Colour Is a Shadow?

    ERIC Educational Resources Information Center

    Hughes, S. W.

    2009-01-01

    What colour is a shadow? Black, grey, or some other colour? This article describes how to use a digital camera to test the hypothesis that a shadow under a clear blue sky has a blue tint. A white sheet of A4 paper was photographed in full sunlight and in shadow under a clear blue sky. The images were analysed using a shareware program called…

  13. Assessment of skin types, skin colours and cutaneous responses to ultraviolet radiation in an Asian population.

    PubMed

    Wee, L K; Chong, T K; Quee, D K

    1997-01-01

    Ninety normal individuals were included in this study on skin types, skin colours and cutaneous responses to ultraviolet radiation. Skin types were recorded using Fitzpatrick's classification, skin colours were measured using the Minolta Chromameter CR-300, and cutaneous responses to UV radiation were measured in terms of minimal erythema dose (MED) to UVA, UVB and the immediate pigment darkening dose to UVA (IPDDA). Skin colour measurements were taken from the right cheek to represent facultative skin colours, and from the buttock to represent constitutive skin colours. The colours measured were expressed by the L x a x b colour space. Skin types and some colour parameters (L and b from covered parts of body) correlated fairly well with the minimal erythema doses (MED) to UVA and UVB. Skin colour measurements are more objective than skin type assessment and could be better markers of photosensitivity. However, there is still considerable overlap in MEDs for persons with different skin colours, and further studies of these parameters are warranted. Our MEDs are higher than other reports on similar skin types and skin colours. This could be due to differences in methodology, genetic make-up or acclimatization from chronic sun exposure. This illustrates the importance of local controls for each institution dealing with photosensitive disorders.

  14. 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.

  15. 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.

  16. Grapheme-colour synaesthesia improves detection of embedded shapes, but without pre-attentive 'pop-out' of synaesthetic colour.

    PubMed

    Ward, Jamie; Jonas, Clare; Dienes, Zoltan; Seth, Anil

    2010-04-01

    For people with synaesthesia letters and numbers may evoke experiences of colour. It has been previously demonstrated that these synaesthetes may be better at detecting a triangle made of 2s among a background of 5s if they perceive 5 and 2 as having different synaesthetic colours. However, other studies using this task (or tasks based on the same principle) have failed to replicate the effect or have suggested alternative explanations of the effect. In this study, we repeat the original study on a larger group of synaesthetes (n = 36) and include, for the first time, an assessment of their self-reported colour experiences. We show that synaesthetes do have a general advantage over controls on this task. However, many synaesthetes report no colour experiences at all during the task. Synaesthetes who do report colour typically experience around one third of the graphemes in the display as coloured. This is more consistent with theories of synaesthesia in which spatial attention needs to be deployed to graphemes for conscious colour experiences to emerge than the interpretation based on 'pop-out'.

  17. Melanin-based colour polymorphism responding to climate change.

    PubMed

    Roulin, Alexandre

    2014-11-01

    Climate warming leads to a decrease in biodiversity. Organisms can deal with the new prevailing environmental conditions by one of two main routes, namely evolving new genetic adaptations or through phenotypic plasticity to modify behaviour and physiology. Melanin-based colouration has important functions in animals including a role in camouflage and thermoregulation, protection against UV-radiation and pathogens and, furthermore, genes involved in melanogenesis can pleiotropically regulate behaviour and physiology. In this article, I review the current evidence that differently coloured individuals are differentially sensitive to climate change. Predicting which of dark or pale colour variants (or morphs) will be more penalized by climate change will depend on the adaptive function of melanism in each species as well as how the degree of colouration covaries with behaviour and physiology. For instance, because climate change leads to a rise in temperature and UV-radiation and dark colouration plays a role in UV-protection, dark individuals may be less affected from global warming, if this phenomenon implies more solar radiation particularly in habitats of pale individuals. In contrast, as desertification increases, pale colouration may expand in those regions, whereas dark colourations may expand in regions where humidity is predicted to increase. Dark colouration may be also indirectly selected by climate warming because genes involved in the production of melanin pigments confer resistance to a number of stressful factors including those associated with climate warming. Furthermore, darker melanic individuals are commonly more aggressive than paler conspecifics, and hence they may better cope with competitive interactions due to invading species that expand their range in northern latitudes and at higher altitudes. To conclude, melanin may be a major component involved in adaptation to climate warming, and hence in animal populations melanin-based colouration is

  18. Melanin-based colour polymorphism responding to climate change.

    PubMed

    Roulin, Alexandre

    2014-11-01

    Climate warming leads to a decrease in biodiversity. Organisms can deal with the new prevailing environmental conditions by one of two main routes, namely evolving new genetic adaptations or through phenotypic plasticity to modify behaviour and physiology. Melanin-based colouration has important functions in animals including a role in camouflage and thermoregulation, protection against UV-radiation and pathogens and, furthermore, genes involved in melanogenesis can pleiotropically regulate behaviour and physiology. In this article, I review the current evidence that differently coloured individuals are differentially sensitive to climate change. Predicting which of dark or pale colour variants (or morphs) will be more penalized by climate change will depend on the adaptive function of melanism in each species as well as how the degree of colouration covaries with behaviour and physiology. For instance, because climate change leads to a rise in temperature and UV-radiation and dark colouration plays a role in UV-protection, dark individuals may be less affected from global warming, if this phenomenon implies more solar radiation particularly in habitats of pale individuals. In contrast, as desertification increases, pale colouration may expand in those regions, whereas dark colourations may expand in regions where humidity is predicted to increase. Dark colouration may be also indirectly selected by climate warming because genes involved in the production of melanin pigments confer resistance to a number of stressful factors including those associated with climate warming. Furthermore, darker melanic individuals are commonly more aggressive than paler conspecifics, and hence they may better cope with competitive interactions due to invading species that expand their range in northern latitudes and at higher altitudes. To conclude, melanin may be a major component involved in adaptation to climate warming, and hence in animal populations melanin-based colouration is

  19. A Different View of Solar Spectral Irradiance Variations: Modeling Total Energy over Six-Month Intervals

    NASA Astrophysics Data System (ADS)

    Woods, Thomas N.; Snow, Martin; Harder, Jerald; Chapman, Gary; Cookson, Angela

    2015-10-01

    A different approach to studying solar spectral irradiance (SSI) variations, without the need for long-term (multi-year) instrument degradation corrections, is examining the total energy of the irradiance variation during 6-month periods. This duration is selected because a solar active region typically appears suddenly and then takes 5 to 7 months to decay and disperse back into the quiet-Sun network. The solar outburst energy, which is defined as the irradiance integrated over the 6-month period and thus includes the energy from all phases of active region evolution, could be considered the primary cause for the irradiance variations. Because solar cycle variation is the consequence of multiple active region outbursts, understanding the energy spectral variation may provide a reasonable estimate of the variations for the 11-year solar activity cycle. The moderate-term (6-month) variations from the Solar Radiation and Climate Experiment (SORCE) instruments can be decomposed into positive (in-phase with solar cycle) and negative (out-of-phase) contributions by modeling the variations using the San Fernando Observatory (SFO) facular excess and sunspot deficit proxies, respectively. These excess and deficit variations are fit over 6-month intervals every 2 months over the mission, and these fitted variations are then integrated over time for the 6-month energy. The dominant component indicates which wavelengths are in-phase and which are out-of-phase with solar activity. The results from this study indicate out-of-phase variations for the 1400 - 1600 nm range, with all other wavelengths having in-phase variations.

  20. Organic compounds of different extractability in total solvent extracts from soils of contrasting water repellency

    NASA Astrophysics Data System (ADS)

    Atanassova, Irena; Doerr, Stefan H.

    2010-05-01

    Previous studies examining organic compounds that may cause water-repellent behaviour of soils have typically focussed on analysing only the lipophilic fraction of extracted material. This study aimed to provide a more comprehensive examination by applying single- and sequential-accelerated solvent extraction (ASE), separation and analysis by GC/MS of the total solvent extracts of three soils taken from under eucalypt vegetation with different levels of water repellency. Water repellency increased in all the soils after extraction with DCM:MeOH (95:5), but was eliminated with iso-propanol/ammonia (95:5). Quantities of major lipid compound classes varied between solvents and soils. Iso-propanol/ammonia (95:5) solvent released saccharides, glycerol, aromatic acids and other polar organic compounds, which were more abundant in fractionated extracts from the single extraction and the third step sequential ASE extraction, than in the extracts from the DCM:MeOH ASE solvent. Dominant compounds extracted from all soils were long-chain alkanols (>C22), palmitic acid, C29 alkane, β-sitosterol, terpenes, terpenoids and other polar compounds. The soil with smallest repellency lacked >C18 fatty acids and had smallest concentrations of alkanols (C26, C28 and C30) and alkanes (C29, C31), but a greater abundance of more complex polar compounds than the more repellent soils. We therefore speculate that the above compounds play an important role in determining the water repellency of the soils tested. The results suggest that one-stage and sequential ASE extractions with iso-propanol:ammonia and subsequent fractionation of extracts are a useful approach in providing a comprehensive assessment of the potential compounds involved in causing soil water repellency.

  1. Colour and chemical changes of the lime wood surface due to CO2 laser thermal modification

    NASA Astrophysics Data System (ADS)

    Kubovský, Ivan; Kačík, František

    2014-12-01

    We studied colour and main wood components changes of lime wood caused by CO2 laser beam irradiation. The dry surface of lime wood (Tilia vulgaris L.) was irradiated with the CO2 laser beam (wavelength of 10.6 μm) at different exposures (expressed as the irradiation dose). Colour changes were monitored by the spectrophotometer, chemical changes were observed by the ATR-FTIR spectroscopy and carbohydrates were analysed by the HPLC method. With the growth of the irradiation dose (from 8.1 to 28.7 J cm-2) lightness (ΔL*) decrease and increase of the total colour difference (ΔE*) were observed. Higher values of the input energy lead to accelerating the mutual reaction of the functional groups resulting in the subsequent condensation of lignin. The total decrease in saccharides at the highest irradiation dose reaches 27.39% of the initial amount of saccharides in the reference sample. We have observed degradation and loss of hemicelluloses.

  2. Microcavity-embedded, colour-tuneable, transparent organic solar cells.

    PubMed

    Chen, Yi-Hong; Chen, Chang-Wen; Huang, Zheng-Yu; Lin, Wei-Chieh; Lin, Li-Yen; Lin, Francis; Wong, Ken-Tsung; Lin, Hao-Wu

    2014-02-01

    In this work microcavity-capped colour-tuneable SMOSCs are evaluated. By adopting a microcavity-structured cathode with optical spacer layers of different thicknesses fabricated in a Ag/NPB/Ag structure, the transmission spectra of complete devices can be tuned over the entire visible-light region (400-750 nm). The fabricated semitransparent colour-tuneable solar cells show an average efficiency of 4.78% under 1-sun illumination.

  3. Colour processing in complex environments: insights from the visual system of bees

    PubMed Central

    Dyer, Adrian G.; Paulk, Angelique C.; Reser, David H.

    2011-01-01

    Colour vision enables animals to detect and discriminate differences in chromatic cues independent of brightness. How the bee visual system manages this task is of interest for understanding information processing in miniaturized systems, as well as the relationship between bee pollinators and flowering plants. Bees can quickly discriminate dissimilar colours, but can also slowly learn to discriminate very similar colours, raising the question as to how the visual system can support this, or whether it is simply a learning and memory operation. We discuss the detailed neuroanatomical layout of the brain, identify probable brain areas for colour processing, and suggest that there may be multiple systems in the bee brain that mediate either coarse or fine colour discrimination ability in a manner dependent upon individual experience. These multiple colour pathways have been identified along both functional and anatomical lines in the bee brain, providing us with some insights into how the brain may operate to support complex colour discrimination behaviours. PMID:21147796

  4. Effect of colour pop-out on the recognition of letters in crowding conditions.

    PubMed

    Põder, Endel

    2007-11-01

    The crowding effect of adjacent objects on the recognition of a target can be reduced when target and flankers differ in some feature, that is irrelevant to the recognition task. In this study, the mechanisms of this effect were explored using targets and flankers of the same and different colours. It was found that facilitation nearly equal to that of differently coloured targets and flankers can be observed with a differently coloured background blob in the location of the target. The different-colour effect does not require advance knowledge of the target and flanker colours, but the effect increases in the course of three trials with constant mapping of colours. The results are consistent with the notion of exogenous attention that facilitates the processing at the most salient locations in the visual field. PMID:16718511

  5. The origins of colour vision in vertebrates.

    PubMed

    Collin, Shaun P; Trezise, Ann E O

    2004-07-01

    The capacity for colour vision is mediated by the comparison of the signal intensities from photoreceptors of two or more types that differ in spectral sensitivity. Morphological, physiological and molecular analyses of the retina in an agnathan (jawless) fish, the lamprey Geotria australis, may hold important clues to the origins of colour vision in vertebrates. Lampreys are extant representatives of an ancient group of vertebrates, the origins of which are thought to date back to at least the early Cambrian, approximately 540 million years ago. G. australis possesses five photoreceptor types, each with cone-like ultrastructural features and different spectral sensitivities. Recent molecular genetic studies have also revealed that five visual pigment (opsin) genes are expressed in the retina, each of which is orthologous to the major classes of vertebrate opsin genes. These findings reveal that multiple opsin genes originated very early in vertebrate evolution, prior to the separation of the jawed and jawless vertebrate lineages, thereby providing the genetic basis for colour vision in all vertebrates.

  6. Colour constancy: influence of viewing behaviour on grey settings.

    PubMed

    Golz, Jürgen

    2010-01-01

    In numerous studies on colour constancy or colour induction subjects have to adjust a test field so that it looks achromatic. Their viewing behaviour during these settings is often not controlled or reported. Here I show that the results of grey settings depend on whether subjects visually explore the stimulus by looking around or fixate their gaze exclusively on the test field. Two different viewing instructions are compared with regard to the degree of constancy as measured by the shift of grey settings in coloured surrounds. In variegated surrounds (but not in uniform surrounds) there is a robust effect of viewing condition for all subjects and all surround chromaticities tested, in that exploration increases colour constancy compared to fixating the test field. Values of a colour constancy index are increased by as much as 20% (where 100% colour constancy means that the subject chooses as grey the mean chromaticity of the surround) with an average across all subjects and surrounds of 12.6%. Thus, if this factor is not experimentally controlled, it could inflate variance, reduce comparability between different studies, and even lead to unwarranted conclusions if viewing behaviour unpredictably differs between experimental conditions.

  7. Two Different Total Hip Arthroplasties for Hartofilakidis Type C1 Developmental Dysplasia of Hip in Adults

    PubMed Central

    Chu, Ya-Ming; Zhou, Yi-Xin; Han, Na; Yang, De-Jin

    2016-01-01

    Background: Total hip arthroplasty (THA) in developmental dysplasia of the hip (DDH) is more complex than the normal hip, with large replacement risks and many complications. Although nonosteotomy THA is convenient to perform, femoral osteotomy shortening can avoid blood vessel and nerve traction injuries. This study aimed to compare osteotomy THA with nonosteotomy to determine reasonable options for operative management of DDH. Methods: Data on 48 DDH patients who underwent THA were analyzed retrospectively. The patients were divided into two groups: Group A 29 cases (nonosteotomy), and group B 19 cases (osteotomy). Harris and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores, limb length discrepancy (LLD), radiological data on the hip, and claudication were evaluated. Data were analyzed by using paired-sample Student's t-test, independent-sample Student's t-test, and Pearson's Chi-square test; the test level was α =0.05. Results: Postoperative Harris (90.7 ± 5.1) and WOMAC scores (88.0 ± 10.6) were significantly improved compared with preoperative Harris (44.8 ± 5.7) and WOMAC scores (42.0 ± 5.3) in group A (P < 0.05). Postoperative Harris (90.4 ± 2.8) and WOMAC scores (88.2 ± 5.9) were significantly improved compared with preoperative Harris (44.4 ± 4.2) and WOMAC scores (43.2 ± 4.3) in group B (P < 0.05). One case of dislocation occurred in group A; after closed reduction, dislocation did not recur. In group A, 2 patients developed cutaneous branch injury of the femoral nerve, which spontaneously recovered without treatment. Postoperative LLD >2 cm was seen in one case in group A and five cases in group B. Postoperative claudication showed no significant difference between the two groups (P > 0.05). No patients developed infection; postoperative X-rays showed that the location of the prosthesis was satisfactory, and the surrounding bone was not dissolved. Conclusions: THA is effective and safe for DDH. For unilateral high

  8. 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

  9. Autumn colours and the nutrient retranslocation hypothesis: a theoretical assessment.

    PubMed

    Archetti, Marco

    2007-02-21

    The adaptive value of the bright colours of leaves in autumn is still debated. It is possible that autumn colours are an adaptation to protect the tree against photoinibition and photooxidation, which allows a more efficient recovery of nutrients. It has been proposed that the preference of aphids for trees that retranslocate nitrogen more efficiently can explain the high diversity of aphids on tree species with bright autumn colours. This scenario however does not take into account the impact of insects on the fitness of the trees and has not been analysed theoretically. Its assumptions and predictions, therefore, remain uncertain. I show with a model of insect-tree interaction that the system can actually evolve under particular conditions. I discuss the differences with the coevolution theory of autumn colours, available evidence and possible tests.

  10. A prospective evaluation of 2 different pain management protocols for total hip arthroplasty.

    PubMed

    Post, Zachary D; Restrepo, Camilo; Kahl, Lauren K; van de Leur, Tim; Purtill, James J; Hozack, William J

    2010-04-01

    Pain management after total hip arthroplasty has improved dramatically in the past decade. However, most protocols use opioid medications for pain control. In the current study, 100 patients were prospectively selected to receive a traditional narcotic-based patient-controlled analgesia protocol or a nonnarcotic oral protocol for pain management after primary total hip arthroplasty. Therapy programs were similar for both groups. Postoperatively, patients were followed daily for opioid use, medication adverse effects, pain control, and overall satisfaction. The nonnarcotic oral group showed lower mean pain scores during the first 24 hours after surgery. The satisfaction rate was high in both groups. Both protocols provided adequate pain control after total hip arthroplasty; the nonnarcotic pain management protocol resulted in significantly decreased opioid consumption and fewer adverse effects.

  11. 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.

  12. Transcript profile of barley aleurone differs between total and polysomal RNAs: Implications for proteome modeling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Microarray analysis of mRNA populations is routinely conducted with total RNA. However, such analyses would probably represent the translated genome (proteome) more accurately if conducted with polysomal RNA. In order to determine whether significant variation occurs between these two populations,...

  13. Gender Differences in Health-Related Quality of Life Following Total Laryngectomy

    ERIC Educational Resources Information Center

    Lee, Mary T.; Gibson, Sam; Hilari, Katerina

    2010-01-01

    Background: The impact of a total laryngectomy on an individual's life has primarily been measured from a male viewpoint reflecting the demographics of a diagnosis of laryngeal cancer. A small number of studies have looked specifically at females, but very few are comparison studies. Consequently, there is little consistent research regarding any…

  14. 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

  15. Heterospecific aggression bias towards a rarer colour morph.

    PubMed

    Lehtonen, Topi K; Sowersby, Will; Wong, Bob B M

    2015-09-22

    Colour polymorphisms are a striking example of phenotypic diversity, yet the sources of selection that allow different morphs to persist within populations remain poorly understood. In particular, despite the importance of aggression in mediating social dominance, few studies have considered how heterospecific aggression might contribute to the maintenance or divergence of different colour morphs. To redress this gap, we carried out a field-based study in a Nicaraguan crater lake to investigate patterns of heterospecific aggression directed by the cichlid fish, Hypsophrys nicaraguensis, towards colour polymorphic cichlids in the genus Amphilophus. We found that H. nicaraguensis was the most frequent territorial neighbour of the colour polymorphic A. sagittae. Furthermore, when manipulating territorial intrusions using models, H. nicaraguensis were more aggressive towards the gold than dark colour morph of the sympatric Amphilophus species, including A. sagittae. Such a pattern of heterospecific aggression should be costly to the gold colour morph, potentially accounting for its lower than expected frequency and, more generally, highlighting the importance of considering heterospecific aggression in the context of morph frequencies and coexistence in the wild. PMID:26378216

  16. Heterospecific aggression bias towards a rarer colour morph.

    PubMed

    Lehtonen, Topi K; Sowersby, Will; Wong, Bob B M

    2015-09-22

    Colour polymorphisms are a striking example of phenotypic diversity, yet the sources of selection that allow different morphs to persist within populations remain poorly understood. In particular, despite the importance of aggression in mediating social dominance, few studies have considered how heterospecific aggression might contribute to the maintenance or divergence of different colour morphs. To redress this gap, we carried out a field-based study in a Nicaraguan crater lake to investigate patterns of heterospecific aggression directed by the cichlid fish, Hypsophrys nicaraguensis, towards colour polymorphic cichlids in the genus Amphilophus. We found that H. nicaraguensis was the most frequent territorial neighbour of the colour polymorphic A. sagittae. Furthermore, when manipulating territorial intrusions using models, H. nicaraguensis were more aggressive towards the gold than dark colour morph of the sympatric Amphilophus species, including A. sagittae. Such a pattern of heterospecific aggression should be costly to the gold colour morph, potentially accounting for its lower than expected frequency and, more generally, highlighting the importance of considering heterospecific aggression in the context of morph frequencies and coexistence in the wild.

  17. Synthetic food colours in saffron solutions, saffron rice and saffron chicken from restaurants in Tehran, Iran.

    PubMed

    Moradi-Khatoonabadi, Zhila; Amirpour, Mansooreh; AkbariAzam, Maryam

    2015-01-01

    Saffron solutions, saffron rice and saffron chicken samples were considered for synthetic colours as additives, which are forbidden according to Iranian national standards. Samples were taken from restaurants of three locations and analysed by high-performance liquid chromatography. Of the total 573 samples, 52% were positive for at least one colour. The most prevalent colours were Tartrazine, Quinoline Yellow and Sunset Yellow, with 44%, 9.1% and 8.4% of the samples testing positive for these colours, respectively. Carmoisine and Ponceau were both detected only in 0.5% of the positive samples and found only in saffron solution. In conclusion, synthetic food colours, especially Tartrazine should be regarded as a potential risk in saffron and its related food. Therefore, new attempts for food safety and quality should be undertaken to eliminate the use of these colours in restaurants. PMID:25116149

  18. Synthetic food colours in saffron solutions, saffron rice and saffron chicken from restaurants in Tehran, Iran.

    PubMed

    Moradi-Khatoonabadi, Zhila; Amirpour, Mansooreh; AkbariAzam, Maryam

    2015-01-01

    Saffron solutions, saffron rice and saffron chicken samples were considered for synthetic colours as additives, which are forbidden according to Iranian national standards. Samples were taken from restaurants of three locations and analysed by high-performance liquid chromatography. Of the total 573 samples, 52% were positive for at least one colour. The most prevalent colours were Tartrazine, Quinoline Yellow and Sunset Yellow, with 44%, 9.1% and 8.4% of the samples testing positive for these colours, respectively. Carmoisine and Ponceau were both detected only in 0.5% of the positive samples and found only in saffron solution. In conclusion, synthetic food colours, especially Tartrazine should be regarded as a potential risk in saffron and its related food. Therefore, new attempts for food safety and quality should be undertaken to eliminate the use of these colours in restaurants.

  19. Material and lighting hues of object colour.

    PubMed

    Tokunaga, Rumi; Logvinenko, Alexander D

    2010-09-01

    Observers can easily differentiate between a pigmented stain and the white surface that it lies on. The same applies for a colour shadow cast upon the same surface. Although the difference between these two kinds of colour appearance (referred to as material and lighting hues) is self-evident even for inexperienced observers, it is not one that has been captured by any colour appearance model thus far. We report here on an experiment supplying evidence for the dissociation of these two types of hue in the perceptual space. The stimulus display consisted of two identical sets of Munsell papers illuminated independently by yellow, neutral, and blue lights. Dissimilarities between all the paper/light pairs were ranked by five trichromatic observers, and then analysed by using non-metric multidimensional scaling (MDS). In the MDS output configuration, the Munsell papers lit by the same light made a closed configuration retaining the same order as in the Munsell book. The paper configurations for the yellow and blue lights were displaced transversally and in parallel to each other, with that of the neutral light located in between. The direction of the shift is interpreted as the yellow-blue lighting dimension. We show that the yellow-blue lighting dimension cannot be reduced to that of the reflected light. PMID:20928959

  20. 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. PMID:27101124

  1. 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.

  2. 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

  3. Opening up a Colourful Cosmic Jewel Box

    NASA Astrophysics Data System (ADS)

    2009-10-01

    and exquisite image quality have resulted in a brand-new, very sharp view despite a total exposure time of just 5 seconds. This new image is one of the best ever taken of this cluster from the ground. The Jewel Box may be visually colourful in images taken on Earth, but observing from space allows the NASA/ESA Hubble Space Telescope to capture light of shorter wavelengths than can not be seen by telescopes on the ground. This new Hubble image of the core of the cluster represents the first comprehensive far ultraviolet to near-infrared image of an open galactic cluster. It was created from images taken through seven filters, allowing viewers to see details never seen before. It was taken near the end of the long life of the Wide Field Planetary Camera 2 ― Hubble's workhorse camera up until the recent Servicing Mission, when it was removed and brought back to Earth. Several very bright, pale blue supergiant stars, a solitary ruby-red supergiant and a variety of other brilliantly coloured stars are visible in the Hubble image, as well as many much fainter ones. The intriguing colours of many of the stars result from their differing intensities at different ultraviolet wavelengths. The huge variety in brightness of the stars in the cluster exists because the brighter stars are 15 to 20 times the mass of the Sun, while the dimmest stars in the Hubble image are less than half the mass of the Sun. More massive stars shine much more brilliantly. They also age faster and make the transition to giant stars much more quickly than their faint, less-massive siblings. The Jewel Box cluster is about 6400 light-years away and is approximately 16 million years old. Notes [1] Open, or galactic, star clusters are not to be confused with globular clusters ― huge balls of tens of thousands of ancient stars in orbit around our galaxy and others. It seems that most stars, including our Sun, formed in open clusters. [2] The Coal Sack is a dark nebula in the Southern Hemisphere, near the

  4. 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

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

    PubMed

    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

  6. Assessment of Antioxidant Potential, Total Phenolics and Flavonoids of Different Solvent Fractions of Monotheca Buxifolia Fruit

    PubMed Central

    Jan, Shumaila; Khan, Muhammad Rashid; Rashid, Umbreen; Bokhari, Jasia

    2013-01-01

    Objectives This study was conducted to investigate the antioxidant potential of methanol extract and its derived fractions (hexane, ethyl acetate, butanol, and aqueous) of fruits of Monotheca buxifolia (Falc.) Dc., a locally used fruit in Pakistan. Methods Dried powder of the fruit of M. buxifolia was extracted with methanol and the resultant was fractionated with solvents having escalating polarity; n-hexane, chloroform, ethyl acetate, n-butanol and the residual soluble aqueous fraction. Total phenolic and total flavonoid contents were estimated for the methanol and various fractions. These fractions were also subjected to various in vitro assays to estimate the scavenging activity for 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), superoxide, hydroxyl, hydrogen peroxide and reductive ability for ferric ions and phosphomolybdate assay. Results The n-butanol, aqueous and methanol fractions possessed high amount of phenolics and flavonoids compared with other fractions, and subsequently showed a pronounced scavenging activity on DPPH, ABTS, superoxide, hydroxyl and hydrogen peroxide radicals and had a potent reductive ability on ferric ion and phosphomolybdate assay. There was a found significant correlation between total phenolic and flavonoid contents and EC50 of DPPH, superoxide, hydrogen peroxide radical and phosphomolybdate assays, whereas a nonsignificant correlation was found with the hydroxyl radical and ABTS radical assay. Conclusion M. buxifolia fruit can be used as natural antioxidant source to prevent damage associated with free radicals. PMID:24298440

  7. Bees' subtle colour preferences: how bees respond to small changes in pigment concentration

    NASA Astrophysics Data System (ADS)

    Papiorek, Sarah; Rohde, Katja; Lunau, Klaus

    2013-07-01

    Variability in flower colour of animal-pollinated plants is common and caused, inter alia, by inter-individual differences in pigment concentrations. If and how pollinators, especially bees, respond to these small differences in pigment concentration is not known, but it is likely that flower colour variability impacts the choice behaviour of all flower visitors that exhibit innate and learned colour preferences. In behavioural experiments, we simulated varying pigment concentrations and studied its impact on the colour choices of bumblebees and honeybees. Individual bees were trained to artificial flowers having a specific concentration of a pigment, i.e. Acridine Orange or Aniline Blue, and then given the simultaneous choice between three test colours including the training colour, one colour of lower and one colour of higher pigment concentration. For each pigment, two set-ups were provided, covering the range of low to middle and the range of middle to high pigment concentrations. Despite the small bee-subjective perceptual contrasts between the tested stimuli and regardless of training towards medium concentrations, bees preferred neither the training stimuli nor the stimuli offering the highest pigment concentration but more often chose those stimuli offering the highest spectral purity and the highest chromatic contrast against the background. Overall, this study suggests that bees choose an intermediate pigment concentration due to its optimal conspicuousness. It is concluded that the spontaneous preferences of bees for flower colours of high spectral purity might exert selective pressure on the evolution of floral colours and of flower pigmentation.

  8. Colour cues facilitate learning flower refill schedules in wild hummingbirds.

    PubMed

    Samuels, Michael; Hurly, T Andrew; Healy, Susan D

    2014-11-01

    Free-living hummingbirds can learn the refill schedules of individual experimental flowers but little is known about what information they use to do this. Colour cues, in particular, may be important to hummingbirds when learning about rewarded flower properties. We investigated, therefore, whether colour cues facilitated the learning of flower refill schedules in wild, free-living rufous hummingbirds (Selasphorus rufus). In the Cued condition, we presented birds with an array of six flowers, three of one colour, each of which were refilled 10min after being emptied by the bird and three of a different colour, which were refilled 20min after being emptied. In the Uncued condition we presented birds with six flowers of the same colour, three of which were refilled after 10min and three of which were refilled after 20min as for the birds in the Cued condition. In the second part of the experiment, we moved the array 2m and changed the shape of the array. Across both phases, birds in the Cued condition learned to discriminate between 10 and 20-min flowers more quickly than did the birds in the Uncued condition. The Cued birds were also better at discriminating between the two distinct refill intervals. Colour cues can, therefore, facilitate learning the refill schedules of experimental flowers in these birds. This article is part of a Special Issue entitled: Cognition in the wild.

  9. Ultra-realistic 3-D imaging based on colour holography

    NASA Astrophysics Data System (ADS)

    Bjelkhagen, H. I.

    2013-02-01

    A review of recent progress in colour holography is provided with new applications. Colour holography recording techniques in silver-halide emulsions are discussed. Both analogue, mainly Denisyuk colour holograms, and digitally-printed colour holograms are described and their recent improvements. An alternative to silver-halide materials are the panchromatic photopolymer materials such as the DuPont and Bayer photopolymers which are covered. The light sources used to illuminate the recorded holograms are very important to obtain ultra-realistic 3-D images. In particular the new light sources based on RGB LEDs are described. They show improved image quality over today's commonly used halogen lights. Recent work in colour holography by holographers and companies in different countries around the world are included. To record and display ultra-realistic 3-D images with perfect colour rendering are highly dependent on the correct recording technique using the optimal recording laser wavelengths, the availability of improved panchromatic recording materials and combined with new display light sources.

  10. Sonographic imaging of extra-testicular focal lesions: comparison of grey-scale, colour Doppler and contrast-enhanced ultrasound.

    PubMed

    Rafailidis, Vasileios; Robbie, Hasti; Konstantatou, Eleni; Huang, Dean Y; Deganello, Annamaria; Sellars, Maria E; Cantisani, Vito; Isidori, Andrea M; Sidhu, Paul S

    2016-02-01

    Extra-testicular lesions are usually benign but present with nonspecific grey-scale sonography findings. This study assesses conventional sonographic characteristics in the differentiation of extra-testicular tumoural from inflammatory lesions and whether contrast-enhanced ultrasound has a role. A retrospective database analysis was performed. All patients were examined by experienced sonographers employing standard techniques combining grey-scale, colour Doppler sonography and contrast-enhanced ultrasound. Features recorded were: clinical symptoms, size, location, echogenicity, colour Doppler sonography and contrast-enhanced ultrasound enhancement. Vascularity on colour Doppler sonography and contrast-enhanced ultrasound was graded and compared. The lesions were classified as tumoural or inflammatory. The Chi-square test was used to analyse the sonographic patterns and kappa coefficient to measure the agreement between colour Doppler sonography and contrast-enhanced ultrasound. A total of 30 lesions were reviewed (median diameter 12 mm, range 5-80 mm, median age 52 years, range 18-86 years), including 13/30 tumoural and 17/30 inflammatory lesions. Lesions were hypoechoic (n = 12), isoechoic (n = 6), hyperechoic (n = 2) or mixed (n = 10). Grey-scale characteristics of tumoural vs. inflammatory lesions differed significantly (P = 0.026). On colour Doppler sonography, lesions had no vessels (n = 16), 2-3 vessels (n = 10) and ≥4 vessels (n = 4). On contrast-enhanced ultrasound, lesions showed no vascularity (n = 17), perfusion similar to testis (n = 7) and higher (n = 6). All abscesses identified (n = 9) showed no vascularity on both colour Doppler sonography and contrast-enhanced ultrasound. There was good agreement between these techniques in evaluating vascularity (κ = 0.719) and no significant difference between colour Doppler sonography and contrast-enhanced ultrasound of tumoural vs. inflammatory lesions

  11. NIR models for predicting total sugar in tobacco for samples with different physical states

    NASA Astrophysics Data System (ADS)

    Qin, Yuhua; Gong, Huili

    2016-07-01

    Due to the spectra variation of the inhomogeneous tobacco flakes results the inaccuracy and instability of the near infrared model. This paper presented the strategies of calibration transfer and hybrid modeling for determining total sugar content in tobacco based on the homogeneous powder model. The necessity judgments and acceptance criteria of the calibration transfer were also proposed. Calibration transfer methods include Slope/Bias Correction (S/B), Piecewise Direct Standardization (PDS), double window piecewise direct standardization (DWPDS), and Shenk's were adopted, a transfer set of 15 samples were chosen for each methods, and the results showed that Shenk's is the adequate transfer method as only one indicator did not fulfill the acceptance criteria of the transfer. Other methods were all dissatisfied with the acceptance criteria and cannot be applied to the calibration transfer between the tobacco flake and powder. While the hybrid model of adding some flake samples to the powder model achieved preferred prediction ability. The study showed that adding around 10% variation samples caused the average prediction error of total sugar content (range 12.1-37.2%) in flake samples from 7.25% (predicted by a flake model) significantly dropping to 4.98%, even close to the prediction of the same powder samples (4.21%) by the powder model. It will valuable for the promotion of the NIR network and online analysis.

  12. Colour constancy as measured by least dissimilar matching.

    PubMed

    Logvinenko, Alexander D; Tokunaga, Rumi

    2011-01-01

    Although asymmetric colour matching has been widely used in experiments on colour constancy, an exact colour match between objects lit by different chromatic lights is impossible to achieve. We used a modification of this technique, instructing our observers to establish the least dissimilar pair of differently illuminated coloured papers. The stimulus display consisted of two identical sets of 22 Munsell papers illuminated independently by neutral, yellow, blue, green and red lights. The lights produced approximately the same illuminance. Four trichromatic observers participated in the experiment. The proportion of exact matches was evaluated. When both sets of papers were lit by the same light, the exact match rate was 0.92, 0.93, 0.84, 0.78 and 0.76 for the neutral, yellow, blue, green and red lights, respectively. When one illumination was neutral and the other chromatic, the exact match rate was 0.80, 0.40, 0.56 and 0.32 for the yellow, blue, green and red lights, respectively. When both lights were chromatic, the exact match rate was found to be even poorer (0.30 on average). Yet, least dissimilar matching was found to be rather systematic. Particularly, a statistical test showed it was symmetric and transitive. The exact match rate was found to be different for different papers, varying from 0.99 (black paper) to 0.12 (purple paper). Such a variation can hardly be expected if observers' judgements were based on an illuminant estimate. We argue that colour constancy cannot be achieved for all the reflecting objects because of mismatching of metamers. We conjecture that the visual system might have evolved to have colour constant perception for some ecologically valid objects at a cost of colour inconstancy for other types of objects. PMID:21902878

  13. Beyond a Dichotomic Approach, the Case of Colour Phenomena

    ERIC Educational Resources Information Center

    Viennot, L.; de Hosson, C.

    2012-01-01

    This research documents the aims and the impact of a teaching experiment concerning colour phenomena. This teaching experiment is designed in order to make students consider not only the spectral composition of light but also its intensity, and to consider the absorption of light by a pigment as relative, instead of as total or zero. Eight…

  14. Co-housing rodents with different coat colours as a simple, non-invasive means of individual identification: validating mixed-strain housing for C57BL/6 and DBA/2 mice.

    PubMed

    Walker, Michael; Fureix, Carole; Palme, Rupert; Mason, Georgia

    2013-01-01

    Standard practice typically requires the marking of laboratory mice so that they can be individually identified. However, many of the common methods compromise the welfare of the individuals being marked (as well as requiring time, effort, and/or resources on the part of researchers and technicians). Mixing strains of different colour within a cage would allow them to be readily visually identifiable, negating the need for more invasive marking techniques. Here we assess the impact that mixed strain housing has on the phenotypes of female C57BL/6 (black) and DBA/2 (brown) mice, and on the variability in the data obtained from them. Mice were housed in either mixed strain or single strain pairs for 19 weeks, and their phenotypes then assessed using 23 different behavioural, morphological, haematological and physiological measures widely used in research and/or important for assessing mouse welfare. No negative effects of mixed strain housing could be found on the phenotypes of either strain, including variables relevant to welfare. Differences and similarities between the two strains were almost all as expected from previously published studies, and none were affected by whether mice were housed in mixed- or single-strain pairs. Only one significant main effect of housing type was detected: mixed strain pairs had smaller red blood cell distribution widths, a measure suggesting better health (findings that now need replicating in case they were Type 1 errors resulting from our multiplicity of tests). Furthermore, mixed strain housing did not increase the variation in data obtained from the mice: the standard errors for all variables were essentially identical between the two housing conditions. Mixed strain housing also made animals very easy to distinguish while in the home cage. Female DBA/2 and C57BL/6 mice can thus be housed in mixed strain pairs for identification purposes, with no apparent negative effects on their welfare or the data they generate. This

  15. Co-Housing Rodents with Different Coat Colours as a Simple, Non-Invasive Means of Individual Identification: Validating Mixed-Strain Housing for C57BL/6 and DBA/2 Mice

    PubMed Central

    Walker, Michael; Fureix, Carole; Palme, Rupert; Mason, Georgia

    2013-01-01

    Standard practice typically requires the marking of laboratory mice so that they can be individually identified. However, many of the common methods compromise the welfare of the individuals being marked (as well as requiring time, effort, and/or resources on the part of researchers and technicians). Mixing strains of different colour within a cage would allow them to be readily visually identifiable, negating the need for more invasive marking techniques. Here we assess the impact that mixed strain housing has on the phenotypes of female C57BL/6 (black) and DBA/2 (brown) mice, and on the variability in the data obtained from them. Mice were housed in either mixed strain or single strain pairs for 19 weeks, and their phenotypes then assessed using 23 different behavioural, morphological, haematological and physiological measures widely used in research and/or important for assessing mouse welfare. No negative effects of mixed strain housing could be found on the phenotypes of either strain, including variables relevant to welfare. Differences and similarities between the two strains were almost all as expected from previously published studies, and none were affected by whether mice were housed in mixed- or single-strain pairs. Only one significant main effect of housing type was detected: mixed strain pairs had smaller red blood cell distribution widths, a measure suggesting better health (findings that now need replicating in case they were Type 1 errors resulting from our multiplicity of tests). Furthermore, mixed strain housing did not increase the variation in data obtained from the mice: the standard errors for all variables were essentially identical between the two housing conditions. Mixed strain housing also made animals very easy to distinguish while in the home cage. Female DBA/2 and C57BL/6 mice can thus be housed in mixed strain pairs for identification purposes, with no apparent negative effects on their welfare or the data they generate. This

  16. Ozone total column and surface comparisons during differing meteorological conditions at Edgewood, MD during summer 2011

    NASA Astrophysics Data System (ADS)

    Stauffer, R. M.; Martins, D. K.; Halliday, H. S.; Thompson, A. M.; Weinheimer, A. J.; Knapp, D. J.; Montzka, D.; Clark, R. D.

    2011-12-01

    Chemical and meteorological measurements were taken during 01 July - 31 July, 2011 in the Mid-Atlantic region as a part of the first year of NASA's DISCOVER-AQ (Deriving Information on Surface Conditions from COlumn and VERtically Resolved Observations Relevant to Air Quality) campaign. The main objective of the project is to relate total column amounts to surface amounts of constituents related to air quality for the improvement of satellite interpretation and diagnosis of surface pollution. The Nittany Atmospheric Trailer and Integrated Validation Experiment (NATIVE) trailer was deployed to Aberdeen Proving Ground in Edgewood, MD during the campaign to provide in-situ, ground-based air quality measurements. NATIVE surface data, as well as coincident free-flying and tethered balloon ozone profiles are compared with observations from a NASA P3B aircraft performing profile spirals directly over the Edgewood site. Phenomena such as bay breeze circulations and their effect on surface and column pollution amounts are also investigated.

  17. Individual differences in physiologic measures are stable across repeated exposures to total sleep deprivation

    PubMed Central

    Chua, Eric Chern‐Pin; Yeo, Sing‐Chen; Lee, Ivan Tian‐Guang; Tan, Luuan‐Chin; Lau, Pauline; Tan, Sara S.; Ho Mien, Ivan; Gooley, Joshua J.

    2014-01-01

    Abstract Some individuals show severe cognitive impairment when sleep deprived, whereas others are able to maintain a high level of performance. Such differences are stable and trait‐like, but it is not clear whether these findings generalize to physiologic responses to sleep loss. Here, we analyzed individual differences in behavioral and physiologic measures in healthy ethnic‐Chinese male volunteers (n = 12; aged 22–30 years) who were kept awake for at least 26 h in a controlled laboratory environment on two separate occasions. Every 2 h, sustained attention performance was assessed using a 10‐min psychomotor vigilance task (PVT), and sleepiness was estimated objectively by determining percentage eyelid closure over the pupil over time (PERCLOS) and blink rate. Between‐subject differences in heart rate and its variability, and electroencephalogram (EEG) spectral power were also analyzed during each PVT. To assess stability of individual differences, intraclass correlation coefficients (ICC) were determined using variance components analysis. Consistent with previous work, individual differences in PVT performance were reproducible across study visits, as were baseline sleep measures prior to sleep deprivation. In addition, stable individual differences were observed during sleep deprivation for PERCLOS, blink rate, heart rate and its variability, and EEG spectral power in the alpha frequency band, even after adjusting for baseline differences in these measures (range, ICC = 0.67–0.91). These findings establish that changes in ocular, ECG, and EEG signals are highly reproducible across a night of sleep deprivation, hence raising the possibility that, similar to behavioral measures, physiologic responses to sleep loss are trait‐like. PMID:25263200

  18. Longitudinal difference in total electron content over the East Asian region: Feature and explanation

    NASA Astrophysics Data System (ADS)

    Yu, Shimei; Xiao, Zuo; Zhao, Biqiang; Zhang, Donghe; Hao, Yongqiang

    2016-10-01

    The mechanism of the longitudinal difference of ionospheric electron density is in general attributed to the thermospheric wind effect modulated by the local geomagnetic declination. Although this mechanism is tested in many case studies, there are other possible factors such as solar activity and so on which still need further investigations. In this paper, TEC data from two Chinese GPS stations located at almost same geographic latitudes but with a wide longitude span (~38°) are used to study the morphological features of longitudinal differences under various geophysical conditions. A parameter Rew is defined as a normalized measure of the TEC difference between the two stations. All the observed temporal variations of Rew are analyzed statistically, with the results showing that negative east-west differences (Western TEC>Eastern TEC) in the noontime are pronounced during Day of Year (DoY) 90-270, while nighttime positive differences (Western TECdifferences in the ionosphere.

  19. The colour of fossil feathers.

    PubMed

    Vinther, Jakob; Briggs, Derek E G; Prum, Richard O; Saranathan, Vinodkumar

    2008-10-23

    Feathers are complex integumentary appendages of birds and some other theropod dinosaurs. They are frequently coloured and function in camouflage and display. Previous investigations have concluded that fossil feathers are preserved as carbonized traces composed of feather-degrading bacteria. Here, an investigation of a colour-banded feather from the Lower Cretaceous Crato Formation of Brazil revealed that the dark bands are preserved as elongate, oblate carbonaceous bodies 1-2 microm long, whereas the light bands retain only relief traces on the rock matrix. Energy dispersive X-ray analysis showed that the dark bands preserve a substantial amount of carbon, whereas the light bands show no carbon residue. Comparison of these oblate fossil bodies with the structure of black feathers from a living bird indicates that they are the eumelanin-containing melanosomes. We conclude that most fossil feathers are preserved as melanosomes, and that the distribution of these structures in fossil feathers can preserve the colour pattern in the original feather. The discovery of preserved melanosomes opens up the possibility of interpreting the colour of extinct birds and other dinosaurs.

  20. Structural colour printing from a reusable generic nanosubstrate masked for the target image.

    PubMed

    Rezaei, M; Jiang, H; Kaminska, B

    2016-02-26

    Structural colour printing has advantages over traditional pigment-based colour printing. However, the high fabrication cost has hindered its applications in printing large-area images because each image requires patterning structural pixels in nanoscale resolution. In this work, we present a novel strategy to print structural colour images from a pixelated substrate which is called a nanosubstrate. The nanosubstrate is fabricated only once using nanofabrication tools and can be reused for printing a large quantity of structural colour images. It contains closely packed arrays of nanostructures from which red, green, blue and infrared structural pixels can be imprinted. To print a target colour image, the nanosubstrate is first covered with a mask layer to block all the structural pixels. The mask layer is subsequently patterned according to the target colour image to make apertures of controllable sizes on top of the wanted primary colour pixels. The masked nanosubstrate is then used as a stamp to imprint the colour image onto a separate substrate surface using nanoimprint lithography. Different visual colours are achieved by properly mixing the red, green and blue primary colours into appropriate ratios controlled by the aperture sizes on the patterned mask layer. Such a strategy significantly reduces the cost and complexity of printing a structural colour image from lengthy nanoscale patterning into high throughput micro-patterning and makes it possible to apply structural colour printing in personalized security features and data storage. In this paper, nanocone array grating pixels were used as the structural pixels and the nanosubstrate contains structures to imprint the nanocone arrays. Laser lithography was implemented to pattern the mask layer with submicron resolution. The optical properties of the nanocone array gratings are studied in detail. Multiple printed structural colour images with embedded covert information are demonstrated. PMID:26820913

  1. Structural colour printing from a reusable generic nanosubstrate masked for the target image

    NASA Astrophysics Data System (ADS)

    Rezaei, M.; Jiang, H.; Kaminska, B.

    2016-02-01

    Structural colour printing has advantages over traditional pigment-based colour printing. However, the high fabrication cost has hindered its applications in printing large-area images because each image requires patterning structural pixels in nanoscale resolution. In this work, we present a novel strategy to print structural colour images from a pixelated substrate which is called a nanosubstrate. The nanosubstrate is fabricated only once using nanofabrication tools and can be reused for printing a large quantity of structural colour images. It contains closely packed arrays of nanostructures from which red, green, blue and infrared structural pixels can be imprinted. To print a target colour image, the nanosubstrate is first covered with a mask layer to block all the structural pixels. The mask layer is subsequently patterned according to the target colour image to make apertures of controllable sizes on top of the wanted primary colour pixels. The masked nanosubstrate is then used as a stamp to imprint the colour image onto a separate substrate surface using nanoimprint lithography. Different visual colours are achieved by properly mixing the red, green and blue primary colours into appropriate ratios controlled by the aperture sizes on the patterned mask layer. Such a strategy significantly reduces the cost and complexity of printing a structural colour image from lengthy nanoscale patterning into high throughput micro-patterning and makes it possible to apply structural colour printing in personalized security features and data storage. In this paper, nanocone array grating pixels were used as the structural pixels and the nanosubstrate contains structures to imprint the nanocone arrays. Laser lithography was implemented to pattern the mask layer with submicron resolution. The optical properties of the nanocone array gratings are studied in detail. Multiple printed structural colour images with embedded covert information are demonstrated.

  2. Breaking the colour-reddening degeneracy in Type Ia supernovae

    NASA Astrophysics Data System (ADS)

    Sasdelli, Michele; Ishida, E. E. O.; Hillebrandt, W.; Ashall, C.; Mazzali, P. A.; Prentice, S. J.

    2016-07-01

    A new method to study the intrinsic colour and luminosity of Type Ia supernovae (SNe Ia) is presented. A metric space built using principal component analysis on a spectral series for SNe Ia between -12.5 and +17.5 d from the B maximum is used as a set of predictors. This metric space is built to be insensitive to reddening. Hence, it does not predict the part of the colour excess due to dust extinction. At the same time, the rich variability of SN Ia spectra is a good predictor of a large fraction of the intrinsic colour variability. Such a metric space is a good predictor of the epoch when the maximum in the B - V colour curve is reached. Multivariate partial least-squares regression predicts the intrinsic B-band light curve and the intrinsic B - V colour curve up to a month after the maximum. This allows us to study the relation between the light curves of SNe Ia and their spectra. The total-to-selective extinction ratio RV in the host galaxy of SNe Ia is found, on average, to be consistent with typical Milky Way values. This analysis shows the importance of collecting spectra to study SNe Ia, even with a large sample publicly available. Future automated surveys, such as the Large Synoptic Survey Telescope, will provide a large number of light curves. The analysis shows that observing accompanying spectra for a significant number of SNe will be important even for normal SNe Ia.

  3. Total polyphenols and antioxidant activity in different species of apples grown in Georgia.

    PubMed

    Gogia, N; Gongadze, M; Bukia, Z; Esaiashvili, M; Chkhikvishvili, I

    2014-01-01

    Many studies have shown that biologically active components in plant-based foods, particularly phytochemicals, have important potential to modulate many processes in the development of diseases, including cancer, cardiovascular disease, diabetes, pulmonary disorders, Alzheimer's disease, and other degenerative diseases. The aim of the our study was to provide an updated understanding and analysis of various apple sorts growing in Georgia by the compounds with a particular focus on their potential role(s) in disease risk and general human health. The Various sorts (Kekhura, Banany, Golden, Starty, Chempion, Aidaridy, Brotsky, Achabety, Sinapy, Jonagold and Antonovka,) of apples were investigated. The total phenolic content and antioxidant activity were studied in peel and flesh extracts and were measured by slightly modified method of Folin-Denis using Folin-Ciocalteu reagent and - 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging method in those varieties of apples. Summarizing our data, we can conclude that, in accordance with the benefit to human health, the most prominent varieties of apples - Kekhura. It is rich with phenolic compounds, and also characterized by high scavenging activity. Also has good features Antonovka and Achabety. It should be noted that apple peel more helpful than the flesh, and therefore during consumption peeling of apples is unacceptable in terms of its usefulness.

  4. Analysis of temperature difference on the total of energy expenditure during static bicycle exercise

    NASA Astrophysics Data System (ADS)

    Sugiono

    2016-04-01

    How to manage energy expenditure for cyclist is very crucial part to achieve a good performance. As the tropical situation, the differences of temperature level might be contributed in energy expenditure and durability. The aim of the paper is to estimate and to analysis the configuration of energy expenditure for static cycling activity based on heart rate value in room with air conditioning (AC)/no AC treatment. The research is started with study literatures of climate factors, temperature impact on human body, and definition of energy expenditure. The next step is design the experiment for 5 participants in 2 difference models for 26.80C – 74% relative humidity (room no AC) and 23,80C – 54.8% relative humidity (room with AC). The participants’ heart rate and blood pressure are measured in rest condition and in cycling condition to know the impact of difference temperature in energy expenditure profile. According to the experiment results, the reducing of the temperature has significantly impact on the decreasing of energy expenditure at average 0.3 Kcal/minute for all 5 performers. Finally, the research shows that climate condition (temperature and relative humidity) are very important factors to manage and to reach a higher performance of cycling sport.

  5. Analysis of temperature difference on the total of energy expenditure during static bicycle exercise

    NASA Astrophysics Data System (ADS)

    Sugiono

    2016-04-01

    How to manage energy expenditure for cyclist is very crucial part to achieve a good performance. As the tropical situation, the differences of temperature level might be contributed in energy expenditure and durability. The aim of the paper is to estimate and to analysis the configuration of energy expenditure for static cycling activity based on heart rate value in room with air conditioning (AC)/no AC treatment. The research is started with study literatures of climate factors, temperature impact on human body, and definition of energy expenditure. The next step is design the experiment for 5 participants in 2 difference models for 26.80C - 74% relative humidity (room no AC) and 23,80C - 54.8% relative humidity (room with AC). The participants’ heart rate and blood pressure are measured in rest condition and in cycling condition to know the impact of difference temperature in energy expenditure profile. According to the experiment results, the reducing of the temperature has significantly impact on the decreasing of energy expenditure at average 0.3 Kcal/minute for all 5 performers. Finally, the research shows that climate condition (temperature and relative humidity) are very important factors to manage and to reach a higher performance of cycling sport.

  6. Sex differences in the contributions of visceral and total body fat to blood pressure in adolescence.

    PubMed

    Pausova, Zdenka; Mahboubi, Amel; Abrahamowicz, Michal; Leonard, Gabriel T; Perron, Michel; Richer, Louis; Veillette, Suzanne; Gaudet, Daniel; Paus, Tomas

    2012-03-01

    Excess body fat deposited viscerally rather than elsewhere in the body is associated with higher risk for hypertension; this relationship is stronger in men than in women. Here we investigated whether similar sex dimorphism exists already in adolescence. A population-based sample of adolescent boys (n=237) and girls (n=262), age 12 to 18 years, was studied. Total body fat (TBF) was assessed with multifrequency bioelectrical impedance, and visceral fat (VF) was quantified with MRI. Blood pressure (BP) was measured beat by beat during an hour-long protocol, including supine, standing, sitting, mental stress, and poststress sections. Multivariate mixed-model analysis was used to assess the relative contributions of TBF and VF to BP during these sections. In boys, BP was strongly positively associated with VF (P<0.0001), whereas it was less strongly and negatively associated with TBF (P=0.004); these relationships did not substantially vary during the protocol. In contrast, in girls, BP was strongly positively associated with TBF (P=0.0006), whereas it was not associated with VF (P=0.08); the relationship with TBF varied during the protocol and was most apparent during mental stress (TBF*section interaction: P=0.002). Furthermore, when waist circumference was included in multivariate models instead of VF, it was not associated with BP in either sex; this indicates that waist circumference may not be an appropriate surrogate for VF. Thus, in adolescence, adiposity-related BP elevation is driven mainly by visceral fat in males and by fat deposited elsewhere in females. This dimorphism suggests sex-specific mechanisms of obesity-induced hypertension and the need for sex-specific criteria of its prevention.

  7. Optimization of inflow waveform phase-difference for minimized total cavopulmonary power loss.

    PubMed

    Dur, Onur; DeGroff, Curt G; Keller, Bradley B; Pekkan, Kerem

    2010-03-01

    The Fontan operation is a palliative surgical procedure performed on children, born with congenital heart defects that have yielded only a single functioning ventricle. The total cavo-pulmonary connection (TCPC) is a common variant of the Fontan procedure, where the superior vena cava (SVC) and inferior vena cava (IVC) are routed directly into the pulmonary arteries (PA). Due to the limited pumping energy available, optimized hemodynamics, in turn, minimized power loss, inside the TCPC pathway is required for the best optimal surgical outcomes. To complement ongoing efforts to optimize the anatomical geometric design of the surgical Fontan templates, here, we focused on the characterization of power loss changes due to the temporal variations in between SVC and IVC flow waveforms. An experimentally validated pulsatile computational fluid dynamics solver is used to quantify the effect of phase-shift between SVC and IVC inflow waveforms and amplitudes on internal energy dissipation. The unsteady hemodynamics of two standard idealized TCPC geometries are presented, incorporating patient-specific real-time PC-MRI flow waveforms of "functional" Fontan patients. The effects of respiration and pulsatility on the internal energy dissipation of the TCPC pathway are analyzed. Optimization of phase-shift between caval flows is shown to lead to lower energy dissipation up to 30% in these idealized models. For physiological patient-specific caval waveforms, the power loss is reduced significantly (up to 11%) by the optimization of all three major harmonics at the same mean pathway flow (3 L/min). Thus, the hemodynamic efficiency of single ventricle circuits is influenced strongly by the caval flow waveform quality, which is regulated through respiratory dependent physiological pathways. The proposed patient-specific waveform optimization protocol may potentially inspire new therapeutic applications to aid postoperative hemodynamics and improve the well being of the Fontan

  8. Colour Vision Deficiency and Physics Teaching

    ERIC Educational Resources Information Center

    Maule, Louise; Featonby, David

    2016-01-01

    1 in 12 males suffer from some form of colour vision deficiency (CVD) which in the present colour dominated world of education presentation can be a severe disadvantage. Although aware of "colourblindness" most teachers make little or no adjustment for these pupils for whom tasks may be more difficult. This article examines colour vision…

  9. Biological Components of Colour Preference in Infancy

    ERIC Educational Resources Information Center

    Franklin, Anna; Bevis, Laura; Ling, Yazhu; Hurlbert, Anya

    2010-01-01

    Adult colour preference has been summarized quantitatively in terms of weights on the two fundamental neural processes that underlie early colour encoding: the S-(L+M) ("blue-yellow") and L-M ("red-green") cone-opponent contrast channels ( Ling, Hurlbert & Robinson, 2006; Hurlbert & Ling, 2007). Here, we investigate whether colour preference in…

  10. Determination of total flavonoids content in fresh Ginkgo biloba leaf with different colors using near infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Shi, Ji-yong; Zou, Xiao-bo; Zhao, Jie-wen; Mel, Holmes; Wang, Kai-liang; Wang, Xue; Chen, Hong

    Total flavonoids content is often considered an important quality index of Ginkgo biloba leaf. The feasibility of using near infrared (NIR) spectra at the wavelength range of 10,000-4000 cm-1 for rapid and nondestructive determination of total flavonoids content in G. biloba leaf was investigated. 120 fresh G. biloba leaves in different colors (green, green-yellowish and yellow) were used to spectra acquisition and total flavonoids determination. Partial least squares (PLS), interval partial least squares (iPLS) and synergy interval partial least squares (SiPLS) were used to develop calibration models for total flavonoids content in two colors leaves (green-yellowish and yellow) and three colors leaves (green, green-yellowish and yellow), respectively. The level of total flavonoids content for green, green-yellowish and yellow leaves was in an increasing order. Two characteristic wavelength regions (5840-6090 cm-1 and 6620-6880 cm-1), which corresponded to the absorptions of two aromatic rings in basic flavonoid structure, were selected by SiPLS. The optimal SiPLS model for total flavonoids content in the two colors leaves (r2 = 0.82, RMSEP = 2.62 mg g-1) had better performance than PLS and iPLS models. It could be concluded that NIR spectroscopy has significant potential in the nondestructive determination of total flavonoids content in fresh G. biloba leaf.

  11. 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. PMID:25502555

  12. Classification of iris colour: review and refinement of a classification schema.

    PubMed

    Mackey, David A; Wilkinson, Colleen H; Kearns, Lisa S; Hewitt, Alex W

    2011-07-01

    Eye colour or, more accurately, iris colour is one of the most obvious physical characteristics of a person. European parents frequently ask the colour of their newborn's eyes, only to see the iris change dramatically during their child's first year of life. Genetic and epidemiological findings have uncovered further details about the basis for iris colour, which may have important implications for further research and treatment of some eye diseases and ocular characteristics. Surprisingly there is no widely recognized classification system for eye colour. An added difficulty when trying to devise an international system is that subtle differences in colour description exist between languages (e.g. hazel vs. auburn). We reviewed the recent and very early literature pertaining to eye colour classification. Recent genetic investigations of eye colour have tended to either use simple (three-category grading systems) or more complex digital colour grading. We present a nine-category grading system. Categories in this novel schema include: (i) light blue; (ii) darker blue; (iii) blue with brown peripupillary ring; (iv) green; (v) green with brown iris ring; (vi) peripheral green central brown; (vii) brown with some peripheral green; (viii) brown; and (ix) dark brown. Although different observers may categorize a person's eye colour differently, it is generally only by an adjacent category. We also describe a continuum of iris pigmentation from a small ring of brown around the pupil to almost complete brown with small peripheral flecks. Digital publishing and assessment of iris colour will result in more standardized classification of iris colour and investigation of its role in eye disease.

  13. [Nutrition, acid-base metabolism, cation-anion difference and total base balance in humans].

    PubMed

    Mioni, R; Sala, P; Mioni, G

    2008-01-01

    The relationship between dietary intake and acid-base metabolism has been investigated in the past by means of the inorganic cation-anion difference (C(+)(nm)-A(-)(nm)) method based on dietary ash-acidity titration after the oxidative combustion of food samples. Besides the inorganic components of TA (A(-)(nm)-C(+)(nm)), which are under renal control, there are also metabolizable components (A(-)(nm)-C(+)(nm)) of TA, which are under the control of the intermediate metabolism. The whole body base balance, NBb(W), is obtained only by the application of C(+)(nm)-A(-)(nm) to food, feces and urine, while the metabolizable component (A(-)(nm)-C(+)(nm)) is disregarded. A novel method has been subsequently suggested to calculate the net balance of fixed acid, made up by the difference between the input of net endogenous acid production: NEAP = SO(4)(2-)+A(-)(m)-(C(+)(nm)-A(-)(nm)), and the output of net acid excretion: NAE = TA + NH(4)(+) - HCO(3)(-). This approach has been criticized because 1) it includes metabolizable acids, whose production cannot be measured independently; 2) the specific control of metabolizable acid and base has been incorrectly attributed to the kidney; 3) the inclusion of A-m in the balance input generates an acid overload; 4) the object of measurement in making up a balance has to be the same, a condition not fulfilled as NEAP is different from NAE. Lastly, by rearranging the net balance of the acid equation, the balance of nonmetabolizable acid equation is obtained. Therefore, any discrepancy between these two equations is due to the inaccuracy in the urine measurement of metabolizable cations and/or anions.

  14. Colouration in crab spiders: substrate choice and prey attraction.

    PubMed

    Heiling, Astrid M; Chittka, Lars; Cheng, Ken; Herberstein, Marie E

    2005-05-01

    Australian crab spiders Thomisus spectabilis ambush pollinating insects, such as honeybees (Apis mellifera) on flowers, and can change their body colour between yellow and white. It is traditionally assumed that the spiders change their colour to match the flower colour, thus rendering them cryptic to insect prey. Here, we test this assumption combining state-of-the-art knowledge of bee vision and behavioural experiments. In the field, yellow spiders are only found on yellow daisies (Chrysanthemum frutescens), whereas white spiders are found on yellow and white daisies. These field patterns were confirmed in the laboratory. When given the choice between white and yellow daisies, yellow spiders preferred yellow daisies, whereas white spiders showed only a slight but non-significant preference for white flowers. Thus, T. spectabilis select background colours according to their own body colour. When viewed from a distance, bees use an achromatic signal produced by their green receptors for target detection. Through this visual channel, white spiders on white flowers, and yellow spiders on yellow flowers are virtually undetectable. From a closer distance of a few centimetres, when bees evaluate colour contrast, the combination of spider colour against different flower backgrounds affected the response of honeybees, but not in ways predicted by a classical crypsis/conspicuousness interpretation. Yellow spiders on yellow flowers are not perfectly matched when interpreted through the colour vision of a honeybee. Nevertheless, honeybees showed indifference to the presence of a spider, equally landing on vacant or spider-occupied flowers. Likewise, white spiders are poorly hidden on white flowers, as white spiders reflect ultraviolet light strongly, while white flowers do not. Surprisingly, bees are attracted to this contrast, and significantly more honeybees preferred white flowers occupied by white spiders. White spiders on yellow flowers produce the highest colour

  15. 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.

  16. Detecting gradual visual changes in colour and brightness agnosia: a double dissociation.

    PubMed

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

    2011-03-01

    Two patients, one with colour agnosia and one with brightness agnosia, performed a task that required the detection of gradual temporal changes in colour and brightness. The results for these patients, who showed anaverage or an above-average performance on several tasks designed to test low-level colour and luminance (contrast) perception in the spatial domain, yielded a double dissociation; the brightness agnosic patient was within the normal range for the coloured stimuli, but much slower to detect brightness differences, whereas the colour agnosic patient was within the normal range for the achromatic stimuli, but much slower for the coloured stimuli. These results suggest that a modality-specific impairment in the detection of gradual temporal changes might be related to, if not underlie, the phenomenon of visual agnosia.

  17. Total lipid production of the green alga Nannochloropsis sp. QII under different nitrogen regimes

    SciTech Connect

    Suen, Yu.; Hubbard, J.S.; Holzer, G.; Tornabene, T.G.

    1987-06-01

    The green alga Nannochloropsis sp. QII was cultivated in media with sufficient and growth-limiting levels of nitrogen (nitrate). Nitrogen deficiency promoted lipid synthesis yielding cells with lipids comprising 55% of the biomass. The major lipids were triacylglycerols (79%), polar lipids (9%) and hydrocarbons (2.5%). The polar lipids consisted of a broad range of phospholipids, glycolipids and sulfolipids. Other lipids identified were pigments, free fatty acids, saponifiable and unsaponifiable sterol derivatives, various glycerides, a family of alkyl-1, 4-dioxane derivatives and a series of alkyl- and hydroxy-alkyl-dimethyl-acetals. Experiments in which /sup 14/CO/sub 2/ was provided at different times in the growth cycle demonstrated that enhanced lipid biosynthesis at low nitrogen levels resulted principally from de novo CO/sub 2/ fixation.

  18. Evaluation of Fenton method and ozone-based processes for colour and organic matter removal from biologically pre-treated swine manure.

    PubMed

    Riaño, Berta; Coca, Mónica; García-González, Mari Cruz

    2014-12-01

    This work evaluates the efficiency of different advanced oxidation processes (Fenton method, O3, H2O2 and O3/H2O2) for removing total COD (TCOD) and colour from biologically pre-treated swine manure. The Fenton process with a dosage of 100 mg L(-1) of Fe(2+) and 800 mg L(-1) of H2O2 resulted in about 78% TCOD and 96% colour reductions at an initial pH=3 after a reaction time of 30 min. Coagulation, rather than oxidation process, was identified as a crucial mechanism for removing pollutants. Otherwise, single ozonation achieved only 27-30% TCOD and 53-88% colour removals for ozone dosages ranging between 0.7 and 4.3 g O3 h(-1) at the original wastewater pH (pH=8.1) after 30 min reaction time. The combined treatment with O3/H2O2 at pH=8.1 did not produce any significant TCOD or colour reduction improvement. Therefore, direct reactions with ozone rather than radical reactions were elucidated as the main removal mechanisms in the ozone-based processes. Finally, a rough estimation of the operational costs involved in each process was also performed to compare their economic feasibility. The findings suggested that the Fenton process was more suitable than ozonation for reducing TCOD and colour from the biologically pre-treated swine manure.

  19. The effect of stress and stress hormones on dynamic colour-change in a sexually dichromatic Australian frog.

    PubMed

    Kindermann, Christina; Narayan, Edward J; Wild, Francis; Wild, Clyde H; Hero, Jean-Marc

    2013-06-01

    Rapid colour changes in vertebrates have fascinated biologists for centuries, herein we demonstrate dynamic colour change in an anuran amphibian, the stony creek frog (Litoria wilcoxii), which turns from brown to bright (lemon) yellow during amplexus. We show this by comparing the colour of baseline (unpaired males) and amplecting (paired) males. We also investigate the possible role of stress and stress hormones on this colour change. Frogs were subjected to four different levels of stressors (handling, toe-clipping, saline injection and adrenocorticotropic hormone [ACTH] injection) and the colour change was measured using digital photography. A comparison of baseline colour and stress hormone (corticosterone) levels was also conducted to give further insight to this topic. From the images, the Red Blue Green (RGB) colour values were calculated, and a principal components analysis (PCA) was used to create a single colour metric (the major axis) as an index of colour in the visible spectrum. A moderate stressor (toe-clipping) led to a significant change in colour (within 10 min) similar to that of amplecting males. Surprisingly, neither a mild stressor (handling and saline injection) nor the maximum stressor (handling and ACTH injection) led to a lightening response. This study confirms that the dynamic male colour change in this species in response to medium stressors adds new knowledge to the understanding of the functional mechanisms of dynamic colour change in amphibians.

  20. Aqueous two-phase based on ionic liquid liquid-liquid microextraction for simultaneous determination of five synthetic food colourants in different food samples by high-performance liquid chromatography.

    PubMed

    Sha, Ou; Zhu, Xiashi; Feng, Yanli; Ma, Weixing

    2015-05-01

    A rapid and effective method of aqueous two-phase systems based on ionic liquid microextraction for the simultaneous determination of five synthetic food colourants (tartrazine, sunset yellow, amaranth, ponceau 4R and brilliant blue) in food samples was established. High-performance liquid chromatography coupled with an ultraviolet detector of variable wavelength was used for the determinations. 1-alkyl-3-methylimidazolium bromide was selected as the extraction reagent. The extraction efficiency of the five colourants in the proposed system is influenced by the types of salts, concentrations of salt and [CnMIM]Br, as well as the extracting time. Under the optimal conditions, the extraction efficiencies for these five colourants were above 95%. The phase behaviours of aqueous two-phase system and extraction mechanism were investigated by UV-vis spectroscopy. This method was applied to the analysis of the five colourants in real food samples with the detection limit of 0.051-0.074 ng/mL. Good spiked recoveries from 93.2% to 98.9% were obtained.

  1. Aqueous two-phase based on ionic liquid liquid-liquid microextraction for simultaneous determination of five synthetic food colourants in different food samples by high-performance liquid chromatography.

    PubMed

    Sha, Ou; Zhu, Xiashi; Feng, Yanli; Ma, Weixing

    2015-05-01

    A rapid and effective method of aqueous two-phase systems based on ionic liquid microextraction for the simultaneous determination of five synthetic food colourants (tartrazine, sunset yellow, amaranth, ponceau 4R and brilliant blue) in food samples was established. High-performance liquid chromatography coupled with an ultraviolet detector of variable wavelength was used for the determinations. 1-alkyl-3-methylimidazolium bromide was selected as the extraction reagent. The extraction efficiency of the five colourants in the proposed system is influenced by the types of salts, concentrations of salt and [CnMIM]Br, as well as the extracting time. Under the optimal conditions, the extraction efficiencies for these five colourants were above 95%. The phase behaviours of aqueous two-phase system and extraction mechanism were investigated by UV-vis spectroscopy. This method was applied to the analysis of the five colourants in real food samples with the detection limit of 0.051-0.074 ng/mL. Good spiked recoveries from 93.2% to 98.9% were obtained. PMID:25529695

  2. Use of hair colouring products and breast cancer risk: a case-control study in Connecticut.

    PubMed

    Zheng, T; Holford, T R; Mayne, S T; Owens, P H; Boyle, P; Zhang, B; Zhang, Y W; Zahm, S H

    2002-08-01

    This case-control study was designed to test the hypothesis that the risk of breast cancer varies by type and colour of the hair colouring products used. A total of 608 cases and 609 controls were included in the study. We found no increased risk associated with the overall use of hair dye products or exclusive use of permanent or temporary types of hair dye products. Among those who reported to have exclusively used semi-permanent types of hair colouring products, some of the ORs were elevated. However, none of the ORs related to age at first use, duration of use, total number of applications, and years since first use, was statistically significant. There was also no increased risk of breast cancer associated with exclusive use of dark or light hair colouring products, or use of mixed types or colours of hair dye products. We also found no increased risk of breast cancer associated with hair dye use based on an individual's reason for using a hair colouring product, such as to cover grey or to change natural hair colour. These data suggest that the use of hair colouring products does not have a major impact on the risk of breast cancer.

  3. Colour annealing - a toy model of colour reconnections

    SciTech Connect

    Sandhoff, Marisa; Skands, Peter; /Fermilab

    2005-12-01

    We present a simple toy model for colour reconnections at the nonperturbative level. The model resembles an annealing-type algorithm and is applicable to any collider and process type, though we argue for a possible enhancement of the effect in hadron-hadron collisions. We present a simple application and study of the consequences for semileptonic t{bar t} events at the Tevatron.

  4. Comparing Single species Toxicity Tests to Mesocosm Community-Level Responses to Total Dissolved Solids Comprised of Different Major Ions

    EPA Science Inventory

    Total Dissolved Solids (TDS) dosing studies representing different sources of ions were conducted from 2011-2015. Emergence responses in stream mesocosms were compared to single-species exposures using a whole effluent testing (WET) format and an ex-situ method (single species te...

  5. [Inherited colour vision deficiencies--from Dalton to molecular genetics].

    PubMed

    Cvetković, Dragana; Cvetković, Dobrosav

    2005-01-01

    In recent years, great advances have been made in our understanding of the molecular basis of colour vision defects, as well as of the patterns of genetic variation in individuals with normal colour vision. Molecular genetic analyses have explained the diversity of types and degrees of severity in colour vision anomalies, their frequencies, pronounced individual variations in test results, etc. New techniques have even enabled the determination of John Dalton's real colour vision defect, 150 years after his death. Inherited colour vision deficiencies most often result from the mutations of genes that encode cone opsins. Cone opsin genes are linked to chromosomes 7 (the S or "blue" gene) and X (the L or "red" gene and the M or "green" gene). The L and M genes are located on the q arm of the X chromosome in a head-to-tail array, composed of 2 to 6 (typically 3) genes--a single L is followed by one or more M genes. Only the first two genes of the array are expressed and contribute to the colour vision phenotype. The high degree of homology (96%) between the L and M genes predisposes them to unequal recombination, leading to gene deletion or the formation of hybrid genes (comprising portions of both the L and M genes), explaining the majority of the common red-green colour vision deficiencies. The severity of any deficiency is influenced by the difference in spectral sensitivity between the opsins encoded by the first two genes of the array. A rare defect, S monochromacy, is caused either by the deletion of the regulatory region of the array or by mutations that inactivate the L and M genes. Most recent research concerns the molecular basis of complete achromatopsia, a rare disorder that involves the complete loss of all cone function. This is not caused by mutations in opsin genes, but in other genes that encode cone-specific proteins, e.g. channel proteins and transducin.

  6. A STANDARDIZED LANTERN FOR TESTING COLOUR VISION.

    PubMed

    Martin, L C

    1939-01-01

    A Lantern for lesting Colour-Vision is arranged to show test colours in pairs as in the Board of Trade Lantern. It is adapted to use electric light, and is standardized by stringent testing. The paper discusses the experiments and considerations which led to the formulation of the allowable tolerances in the transmission and colour co-ordinate specifications of the filters, the colour temperature of the lamps and so on. The results of tests on normal and colour-defective subjects are described.

  7. Colour, pleasantness, and consumption behaviour within a meal.

    PubMed

    Piqueras-Fiszman, Betina; Spence, Charles

    2014-04-01

    It is often claimed that colour (e.g., in a meal) affects consumption behaviour. However, just how strong is the evidence in support of this claim, and what are the underlying mechanisms? It has been shown that not only the colour itself, but also the variety and the arrangement of the differently-coloured components in a meal influence consumers' ratings of the pleasantness of a meal (across time) and, to a certain extent, might even affect their consumption behaviour as well. Typically, eating the same food constantly or repeatedly leads to a decrease in its perceived pleasantness, which, as a consequence, might lead to decreased intake of that food. However, variation within a meal (in one or several sensory attributes, or holistically) has been shown to slow down this process. In this review, we first briefly summarize the literature on how general variety in a meal influences these variables and the major theories that have been put forward by researchers to explain them. We then go on to evaluate the evidence of these effects based mainly on the colour of the food explaining the different processes that might affect colour-based sensory-specific satiety and, in more detail, consumption behaviour. In addition, we also discuss the overlap in the definitions of these terms and provide additional hypothesis as to why, in some cases, the opposite pattern of results has been observed.

  8. Innate colour preferences of the Australian native stingless bee Tetragonula carbonaria Sm.

    PubMed

    Dyer, Adrian G; Boyd-Gerny, Skye; Shrestha, Mani; Lunau, Klaus; Garcia, Jair E; Koethe, Sebastian; Wong, Bob B M

    2016-10-01

    Innate preferences promote the capacity of pollinators to find flowers. Honeybees and bumblebees have strong preferences for 'blue' stimuli, and flowers of this colour typically present higher nectar rewards. Interestingly, flowers from multiple different locations around the world independently have the same distribution in bee colour space. Currently, however, there is a paucity of data on the innate colour preferences of stingless bees that are often implicated as being key pollinators in many parts of the world. In Australia, the endemic stingless bee Tetragonula carbonaria is widely distributed and known to be an efficient pollinator of both native plants and agricultural crops. In controlled laboratory conditions, we tested the innate colour responses of naïve bees using standard broadband reflectance stimuli representative of common flower colours. Colorimetric analyses considering hymenopteran vision and a hexagon colour space revealed a difference between test colonies, and a significant effect of green contrast and an interaction effect of green contrast with spectral purity on bee choices. We also observed colour preferences for stimuli from the blue and blue-green categorical regions of colour space. Our results are discussed in relation to the similar distribution of flower colours observed from bee pollination around the world. PMID:27316718

  9. 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.

  10. Innate colour preferences of the Australian native stingless bee Tetragonula carbonaria Sm.

    PubMed

    Dyer, Adrian G; Boyd-Gerny, Skye; Shrestha, Mani; Lunau, Klaus; Garcia, Jair E; Koethe, Sebastian; Wong, Bob B M

    2016-10-01

    Innate preferences promote the capacity of pollinators to find flowers. Honeybees and bumblebees have strong preferences for 'blue' stimuli, and flowers of this colour typically present higher nectar rewards. Interestingly, flowers from multiple different locations around the world independently have the same distribution in bee colour space. Currently, however, there is a paucity of data on the innate colour preferences of stingless bees that are often implicated as being key pollinators in many parts of the world. In Australia, the endemic stingless bee Tetragonula carbonaria is widely distributed and known to be an efficient pollinator of both native plants and agricultural crops. In controlled laboratory conditions, we tested the innate colour responses of naïve bees using standard broadband reflectance stimuli representative of common flower colours. Colorimetric analyses considering hymenopteran vision and a hexagon colour space revealed a difference between test colonies, and a significant effect of green contrast and an interaction effect of green contrast with spectral purity on bee choices. We also observed colour preferences for stimuli from the blue and blue-green categorical regions of colour space. Our results are discussed in relation to the similar distribution of flower colours observed from bee pollination around the world.

  11. The neural correlate of colour distances revealed with competing synaesthetic and real colours.

    PubMed

    Laeng, Bruno; Hugdahl, Kenneth; Specht, Karsten

    2011-03-01

    Synaesthetes claim to perceive illusory colours when reading alphanumeric symbols so that two colours are said to be bound to the same letter or digit (i.e., the colour of the ink, e.g., black, and an additional, synaesthetic, colour). To explore the neural correlates of this phenomenon, we used a Stroop single-letter colour-naming task and found that distances in colour space between the illusory and real colours of a letter target (as computed from either the RGB or CIExyY coordinates of colours) systematically influenced the degree of neuronal activation in colour-processing brain regions. The synaesthetes also activated the same fronto-parietal network during the classic colour-word Stroop task and single-letter tasks. We conclude that the same neural substrate that supports the conscious experience of colour, as triggered by physical wavelength, supports the experience of synaesthetic colours. Thus, two colour attributes (one that is wavelength-dependent and one that is illusory) can be bound to the same stimulus position and simultaneously engage the colour areas in proportion to their similarity in colour space.

  12. 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.

  13. Hair colouring, permanent styling and hair structure.

    PubMed

    Harrison, S; Sinclair, R

    2003-07-01

    Hair is an important component of body image and has immense psychological importance for both men and women. Women, in particular, over the ages have modified their appearance through changing their hair colour or style. Hair can be straight, wavy or curly, blonde, black, brown or red. These natural variations are an important part of our identity that can be manipulated according to the dictates of fashion, culture or society. Different types of hair have varying affinity for the different colouring and waving methods. Damaged hair also has a different affinity for hair products than normal healthy hair. The hair shaft is remarkably strong and resistant to the extremes of nature. Hair cosmetics are widely available and manipulate the structural properties of hair. Whilst most procedures are safe, there is considerable potential for damage to the hair and hair problems of acute onset, including hair breakage, hair loss and loss of condition, are frequently blamed on the last product used on the hair. Hair problems are particularly prevalent among people who repeatedly alter the natural style of their hair.

  14. Printing colour at the optical diffraction limit.

    PubMed

    Kumar, Karthik; Duan, Huigao; Hegde, Ravi S; Koh, Samuel C W; Wei, Jennifer N; Yang, Joel K W

    2012-09-01

    The highest possible resolution for printed colour images is determined by the diffraction limit of visible light. To achieve this limit, individual colour elements (or pixels) with a pitch of 250 nm are required, translating into printed images at a resolution of ∼100,000 dots per inch (d.p.i.). However, methods for dispensing multiple colourants or fabricating structural colour through plasmonic structures have insufficient resolution and limited scalability. Here, we present a non-colourant method that achieves bright-field colour prints with resolutions up to the optical diffraction limit. Colour information is encoded in the dimensional parameters of metal nanostructures, so that tuning their plasmon resonance determines the colours of the individual pixels. Our colour-mapping strategy produces images with both sharp colour changes and fine tonal variations, is amenable to large-volume colour printing via nanoimprint lithography, and could be useful in making microimages for security, steganography, nanoscale optical filters and high-density spectrally encoded optical data storage.

  15. Colour dependence of zodiacal light models

    NASA Technical Reports Server (NTRS)

    Giese, R. H.; Hanner, M. S.; Leinert, C.

    1973-01-01

    Colour models of the zodiacal light in the ecliptic have been calculated for both dielectric and metallic particles in the sub-micron and micron size range. Two colour ratios were computed, a blue ratio and a red ratio. The models with a size distribution proportional to s to the -2.5 power ds (where s is the particle radius) generally show a colour close to the solar colour and almost independent of elongation. Especially in the blue colour ratio there is generally no significant dependence on the lower cutoff size (0.1-1 micron). The main feature of absorbing particles is a reddening at small elongations. The models for size distributions proportional to s to the -4 power ds show larger departures from solar colour and more variation with model parameters. Colour measurements, including red and near infra-red, therefore are useful to distinguish between flat and steep size spectra and to verify the presence of slightly absorbing particles.

  16. A guide to the field of palaeo colour: Melanin and other pigments can fossilise: Reconstructing colour patterns from ancient organisms can give new insights to ecology and behaviour.

    PubMed

    Vinther, Jakob

    2015-06-01

    Melanin, and other pigments have recently been shown to preserve over geologic time scales, and are found in several different organisms. This opens up the possibility of inferring colours and colour patterns ranging from invertebrates to feathered dinosaurs and mammals. An emerging discipline is palaeo colour: colour plays an important role in display and camouflage as well as in integumental strengthening and protection, which makes possible the hitherto difficult task of doing inferences about past ecologies, behaviours, and organismal appearance. Several studies and techniques have been presented in the last couple of years that have described ways to characterize pigment patterns. Here, I will review the available methods and the likely applications to understand past ecologies. A golden age of colourized dinosaurs and other animals is now dawning upon us, which may elucidate the nature of ancient predator prey interactions and display structures.

  17. Capture by colour: evidence for dimension-specific singleton capture.

    PubMed

    Harris, Anthony M; Becker, Stefanie I; Remington, Roger W

    2015-10-01

    Previous work on attentional capture has shown the attentional system to be quite flexible in the stimulus properties it can be set to respond to. Several different attentional "modes" have been identified. Feature search mode allows attention to be set for specific features of a target (e.g., red). Singleton detection mode sets attention to respond to any discrepant item ("singleton") in the display. Relational search sets attention for the relative properties of the target in relation to the distractors (e.g., redder, larger). Recently, a new attentional mode was proposed that sets attention to respond to any singleton within a particular feature dimension (e.g., colour; Folk & Anderson, 2010). We tested this proposal against the predictions of previously established attentional modes. In a spatial cueing paradigm, participants searched for a colour target that was randomly either red or green. The nature of the attentional control setting was probed by presenting an irrelevant singleton cue prior to the target display and assessing whether it attracted attention. In all experiments, the cues were red, green, blue, or a white stimulus rapidly rotated (motion cue). The results of three experiments support the existence of a "colour singleton set," finding that all colour cues captured attention strongly, while motion cues captured attention only weakly or not at all. Notably, we also found that capture by motion cues in search for colour targets was moderated by their frequency; rare motion cues captured attention (weakly), while frequent motion cues did not.

  18. On Colour, Category Effects, and Alzheimer's Disease: A Critical Review of Studies and Further Longitudinal Evidence

    PubMed Central

    Moreno-Martínez, F. Javier; Rodríguez-Rojo, Inmaculada C.

    2015-01-01

    The role of colour in object recognition is controversial; in this study, a critical review of previous studies, as well as a longitudinal study, was conducted. We examined whether colour benefits the ability of Alzheimer's disease (AD) patients and normal controls (NC) when naming items differing in colour diagnosticity: living things (LT) versus nonliving things (NLT). Eleven AD patients were evaluated twice with a temporal interval of 3 years; 26 NC were tested once. The participants performed a naming task (colour and greyscale photographs); the impact of nuisance variables (NVs) and potential ceiling effects were also controlled. Our results showed that (i) colour slightly favoured processing of items with higher colour diagnosticity (i.e., LT) in both groups; (ii) AD patients used colour information similarly to NC, retaining this ability over time; (iii) NVs played a significant role as naming predictors in all the participants, relegating domain to a minor plane; and (iv) category effects (better processing of NLT) were present in both groups. Finally, although patients underwent semantic longitudinal impairment, this was independent of colour deterioration. This finding provides better support to the view that colour is effective at the visual rather than at the semantic level of object processing. PMID:26074675

  19. On Colour, Category Effects, and Alzheimer's Disease: A Critical Review of Studies and Further Longitudinal Evidence.

    PubMed

    Moreno-Martínez, F Javier; Rodríguez-Rojo, Inmaculada C

    2015-01-01

    The role of colour in object recognition is controversial; in this study, a critical review of previous studies, as well as a longitudinal study, was conducted. We examined whether colour benefits the ability of Alzheimer's disease (AD) patients and normal controls (NC) when naming items differing in colour diagnosticity: living things (LT) versus nonliving things (NLT). Eleven AD patients were evaluated twice with a temporal interval of 3 years; 26 NC were tested once. The participants performed a naming task (colour and greyscale photographs); the impact of nuisance variables (NVs) and potential ceiling effects were also controlled. Our results showed that (i) colour slightly favoured processing of items with higher colour diagnosticity (i.e., LT) in both groups; (ii) AD patients used colour information similarly to NC, retaining this ability over time; (iii) NVs played a significant role as naming predictors in all the participants, relegating domain to a minor plane; and (iv) category effects (better processing of NLT) were present in both groups. Finally, although patients underwent semantic longitudinal impairment, this was independent of colour deterioration. This finding provides better support to the view that colour is effective at the visual rather than at the semantic level of object processing.

  20. A neuronal circuit for colour vision based on rod-cone opponency.

    PubMed

    Joesch, Maximilian; Meister, Markus

    2016-04-14

    In bright light, cone-photoreceptors are active and colour vision derives from a comparison of signals in cones with different visual pigments. This comparison begins in the retina, where certain retinal ganglion cells have 'colour-opponent' visual responses-excited by light of one colour and suppressed by another colour. In dim light, rod-photoreceptors are active, but colour vision is impossible because they all use the same visual pigment. Instead, the rod signals are thought to splice into retinal circuits at various points, in synergy with the cone signals. Here we report a new circuit for colour vision that challenges these expectations. A genetically identified type of mouse retinal ganglion cell called JAMB (J-RGC), was found to have colour-opponent responses, OFF to ultraviolet (UV) light and ON to green light. Although the mouse retina contains a green-sensitive cone, the ON response instead originates in rods. Rods and cones both contribute to the response over several decades of light intensity. Remarkably, the rod signal in this circuit is antagonistic to that from cones. For rodents, this UV-green channel may play a role in social communication, as suggested by spectral measurements from the environment. In the human retina, all of the components for this circuit exist as well, and its function can explain certain experiences of colour in dim lights, such as a 'blue shift' in twilight. The discovery of this genetically defined pathway will enable new targeted studies of colour processing in the brain.

  1. On Colour, Category Effects, and Alzheimer's Disease: A Critical Review of Studies and Further Longitudinal Evidence.

    PubMed

    Moreno-Martínez, F Javier; Rodríguez-Rojo, Inmaculada C

    2015-01-01

    The role of colour in object recognition is controversial; in this study, a critical review of previous studies, as well as a longitudinal study, was conducted. We examined whether colour benefits the ability of Alzheimer's disease (AD) patients and normal controls (NC) when naming items differing in colour diagnosticity: living things (LT) versus nonliving things (NLT). Eleven AD patients were evaluated twice with a temporal interval of 3 years; 26 NC were tested once. The participants performed a naming task (colour and greyscale photographs); the impact of nuisance variables (NVs) and potential ceiling effects were also controlled. Our results showed that (i) colour slightly favoured processing of items with higher colour diagnosticity (i.e., LT) in both groups; (ii) AD patients used colour information similarly to NC, retaining this ability over time; (iii) NVs played a significant role as naming predictors in all the participants, relegating domain to a minor plane; and (iv) category effects (better processing of NLT) were present in both groups. Finally, although patients underwent semantic longitudinal impairment, this was independent of colour deterioration. This finding provides better support to the view that colour is effective at the visual rather than at the semantic level of object processing. PMID:26074675

  2. An R2R3 MYB transcription factor determines red petal colour in an Actinidia (kiwifruit) hybrid population

    PubMed Central

    2013-01-01

    Background Red colour in kiwifruit results from the presence of anthocyanin pigments. Their expression, however, is complex, and varies among genotypes, species, tissues and environments. An understanding of the biosynthesis, physiology and genetics of the anthocyanins involved, and the control of their expression in different tissues, is required. A complex, the MBW complex, consisting of R2R3-MYB and bHLH transcription factors together with a WD-repeat protein, activates anthocyanin 3-O-galactosyltransferase (F3GT1) to produce anthocyanins. We examined the expression and genetic control of anthocyanins in flowers of Actinidia hybrid families segregating for red and white petal colour. Results Four inter-related backcross families between Actinidia chinensis Planch. var. chinensis and Actinidia eriantha Benth. were identified that segregated 1:1 for red or white petal colour. Flower pigments consisted of five known anthocyanins (two delphinidin-based and three cyanidin-based) and three unknowns. Intensity and hue differed in red petals from pale pink to deep magenta, and while intensity of colour increased with total concentration of anthocyanin, no association was found between any particular anthocyanin data and hue. Real time qPCR demonstrated that an R2R3 MYB, MYB110a, was expressed at significant levels in red-petalled progeny, but not in individuals with white petals. A microsatellite marker was developed that identified alleles that segregated with red petal colour, but not with ovary, stamen filament, or fruit flesh colour in these families. The marker mapped to chromosome 10 in Actinidia. The white petal phenotype was complemented by syringing Agrobacterium tumefaciens carrying Actinidia 35S::MYB110a into the petal tissue. Red pigments developed in white petals both with, and without, co-transformation with Actinidia bHLH partners. MYB110a was shown to directly activate Actinidia F3GT1 in transient assays. Conclusions The transcription factor, MYB110a

  3. Put on that colour, it fits your emotion: Colour appropriateness as a function of expressed emotion.

    PubMed

    Dael, Nele; Perseguers, Marie-Noëlle; Marchand, Cynthia; Antonietti, Jean-Philippe; Mohr, Christine

    2016-01-01

    People associate affective meaning with colour, and this may influence decisions about colours. Hue is traditionally considered the most salient descriptor of colour and colour-affect associations, although colour brightness and saturation seem to have particularly strong affective connotations. To test whether colour choices can be driven by emotion, we investigated whether and how colour hue, brightness, and saturation are systematically associated with bodily expressions of positive (joy) and negative (fear) emotions. Twenty-five non-colour-blind participants viewed videos of these expressions and selected for each video the most appropriate colour using colour sliders providing values for hue, brightness, and saturation. The overall colour choices were congruent with the expressed emotion--that is, participants selected brighter and more saturated colours for joy expressions than for fear expressions. Also, colours along the red-yellow spectrum were deemed more appropriate for joy expressions and cyan-bluish hues for fear expressions. The current study adds further support to the role of emotion in colour choices by (a) showing that emotional information is spontaneously used in an unconstrained choice setting, (b) extending to ecologically valid stimuli occurring in everyday encounters (dressed bodies), and PMID:26339950

  4. Put on that colour, it fits your emotion: Colour appropriateness as a function of expressed emotion.

    PubMed

    Dael, Nele; Perseguers, Marie-Noëlle; Marchand, Cynthia; Antonietti, Jean-Philippe; Mohr, Christine

    2016-01-01

    People associate affective meaning with colour, and this may influence decisions about colours. Hue is traditionally considered the most salient descriptor of colour and colour-affect associations, although colour brightness and saturation seem to have particularly strong affective connotations. To test whether colour choices can be driven by emotion, we investigated whether and how colour hue, brightness, and saturation are systematically associated with bodily expressions of positive (joy) and negative (fear) emotions. Twenty-five non-colour-blind participants viewed videos of these expressions and selected for each video the most appropriate colour using colour sliders providing values for hue, brightness, and saturation. The overall colour choices were congruent with the expressed emotion--that is, participants selected brighter and more saturated colours for joy expressions than for fear expressions. Also, colours along the red-yellow spectrum were deemed more appropriate for joy expressions and cyan-bluish hues for fear expressions. The current study adds further support to the role of emotion in colour choices by (a) showing that emotional information is spontaneously used in an unconstrained choice setting, (b) extending to ecologically valid stimuli occurring in everyday encounters (dressed bodies), and

  5. Differences in gait characteristics between total hip, knee, and ankle arthroplasty patients: a six-month postoperative comparison

    PubMed Central

    2013-01-01

    Background The recovery of gait ability is one of the primary goals for patients following total arthroplasty of lower-limb joints. The aim of this study was to objectively compare gait differences of patients after unilateral total hip arthroplasty (THA), total knee arthroplasty (TKA) and total ankle arthroplasty (TAA) with a group of healthy controls. Methods A total of 26 TAA, 26 TKA and 26 THA patients with a mean (± SD) age of 64 (± 9) years were evaluated six months after surgery and compared with 26 matched healthy controls. Subjects were asked to walk at self-selected normal and fast speeds on a validated pressure mat. The following spatiotemporal gait parameters were measured: walking velocity, cadence, single-limb support (SLS) time, double-limb support (DLS) time, stance time, step length and step width. Results TAA and TKA patients walked slower than controls at normal (p<0.05) and fast speeds (p<0.01). The involved side of TAA and TKA patients showed shorter SLS compared to controls at both normal and fast speeds (p<0.01). Regardless of walking speed, the uninvolved side of TAA and TKA patients demonstrated longer stance time and shorter step length than controls (p<0.01). TAA patients showed shorter SLS of the involved side, longer stance time and shorter step length of the uninvolved side compared to the contralateral side at both normal and fast speeds (p<0.001). Conclusions Gait disability after unilateral lower-limb joint arthroplasty was more marked for distal than for proximal joints at six months after surgery, with a proximal-to-distal progression in the impairment (TAA>TKA>THA). THA patients demonstrated no gait differences compared with controls. In contrast, TAA and TKA patients still demonstrated gait differences compared to controls, with slower walking velocity and reduced SLS in the involved limb. In addition, TAA patients presented marked side-to-side asymmetries in gait characteristics. PMID:23731906

  6. Colour Stability of Heat and Cold Cure Acrylic Resins

    PubMed Central

    Ganesh, P R; Reddy, Madan Mohan; Ebenezar, A.V. Rajesh; Sivakumar, G

    2015-01-01

    Introduction: To evaluate the colour stability of heat and cold cure acrylic resins under simulated oral conditions with different colorants. Materials and Methods: Three different brands of heat cure acrylic resin and two rapid cure auto polymerizing acrylic resin of commercial products such as Trevelon Heat Cure (THC), DPI Heat cure (DHC), Pyrax Heat Cure (PHC), DPI Cold cure (DCC) and Acralyn-R-Cold cure (ACC) have been evaluated for discoloration and colour variation on subjecting it to three different, commonly employed food colorants such as Erythrosine, Tartarizine and Sunset yellow. In order to simulate the oral condition the food colorants were diluted with artificial saliva to the samples taken up for the study. These were further kept in an incubator at 37°C ± 1°C. The UV-visible spectrophotometer has been utilized to evaluate the study on the basis of CIE L* a* b* system. The prepared samples for standard evaluation have been grouped as control group, which has been tested with a white as standard, which is applicable for testing the colour variants. Results: The least colour changes was found to be with Sunset Yellow showing AE* value of 3.55 with heat cure acrylic resin branded as PHC material and the highest colour absorption with Tartarizine showing AE* value of 12.43 in rapid cure autopolymerzing acrylic resin material branded as ACC material. Conclusion: ACC which is a self cure acrylic resin shows a higher colour variation to the tartarizine food coloration. There were not much of discoloration values shown on the denture base resins as the food colorants are of organic azodyes. PMID:25738078

  7. A cross-cultural study of colour grouping: evidence for weak linguistic relativity.

    PubMed

    Davies, I R; Corbett, G G

    1997-08-01

    We report a cross-cultural study of colour grouping carried out as a test of the Sapir-Whorf hypothesis (linguistic relativity theory). Speakers of English, Russian and Setswana-languages that differ in their number of basic colour terms, and in how the blue-green region is categorized--were compared on a colour sorting task. Informants sorted a representative set of 65 colours into groups so that members of the groups looked similar to each other, with no restriction on the number of groups formed. If linguistic relativity theory is true, then there should be reliable differences between the three samples in the composition of the groups they formed associated with the differing positions of colour category boundaries in the languages. The most striking feature of the results, inconsistent with linguistic relativity theory, was the similarity amongst the patterns of choice of the three samples. However, there were also significant differences amongst the samples. Setswana speakers (who have a single basic term for BLUE or GREEN) were more likely to group BLUE colours with GREEN colours than either English or Russian speakers. But Russian speakers (who have two basic colour terms for BLUE) were no more likely than English speakers to group light and dark BLUE separately. In addition there were general structural differences in grouping among the samples: they differed in the level of consensus in grouping, the number of groups formed and in the distribution of the number of colours placed in a group. These structural differences may reflect differences in the availability and salience of the colour categories across the languages. Our data support perceptual universalism modulated by weaker linguistic effects. PMID:9290238

  8. A cross-cultural study of colour grouping: evidence for weak linguistic relativity.

    PubMed

    Davies, I R; Corbett, G G

    1997-08-01

    We report a cross-cultural study of colour grouping carried out as a test of the Sapir-Whorf hypothesis (linguistic relativity theory). Speakers of English, Russian and Setswana-languages that differ in their number of basic colour terms, and in how the blue-green region is categorized--were compared on a colour sorting task. Informants sorted a representative set of 65 colours into groups so that members of the groups looked similar to each other, with no restriction on the number of groups formed. If linguistic relativity theory is true, then there should be reliable differences between the three samples in the composition of the groups they formed associated with the differing positions of colour category boundaries in the languages. The most striking feature of the results, inconsistent with linguistic relativity theory, was the similarity amongst the patterns of choice of the three samples. However, there were also significant differences amongst the samples. Setswana speakers (who have a single basic term for BLUE or GREEN) were more likely to group BLUE colours with GREEN colours than either English or Russian speakers. But Russian speakers (who have two basic colour terms for BLUE) were no more likely than English speakers to group light and dark BLUE separately. In addition there were general structural differences in grouping among the samples: they differed in the level of consensus in grouping, the number of groups formed and in the distribution of the number of colours placed in a group. These structural differences may reflect differences in the availability and salience of the colour categories across the languages. Our data support perceptual universalism modulated by weaker linguistic effects.

  9. Training Grapheme-Colour Associations Produces a Synaesthetic Stroop Effect, but Not a Conditioned Synaesthetic Response

    ERIC Educational Resources Information Center

    Meier, Beat; Rothen, Nicolas

    2009-01-01

    The goal of this study was to investigate whether behavioural and physiological consequences of synaesthesia can be elicited by training specific letter-colour associations. Towards this goal 20 non-synaesthetic individuals were trained for 10 min on 7 consecutive days to associate four different letters with four specific colours. After training,…

  10. Addition Table of Colours: Additive and Subtractive Mixtures Described Using a Single Reasoning Model

    ERIC Educational Resources Information Center

    Mota, A. R.; Lopes dos Santos, J. M. B.

    2014-01-01

    Students' misconceptions concerning colour phenomena and the apparent complexity of the underlying concepts--due to the different domains of knowledge involved--make its teaching very difficult. We have developed and tested a teaching device, the addition table of colours (ATC), that encompasses additive and subtractive mixtures in a single…

  11. A frameshift mutation in the melanophilin gene causes the dilute coat colour in rabbit (Oryctolagus cuniculus) breeds.

    PubMed

    Fontanesi, L; Scotti, E; Allain, D; Dall'olio, S

    2014-04-01

    In rabbit, the dilute locus is determined by a recessive mutated allele (d) that causes the dilution of both eumelanic and pheomelanic pigmentations. In mice, similar phenotypes are determined by mutations in the myosin VA, Rab27a and melanophilin (MLPH) genes. In this study, we investigated the rabbit MLPH gene and showed that a mutation in this gene appears responsible for the dilute coat colour in this species. Checkered Giant F1 families segregating for black and grey (diluted or blue) coat colour were first genotyped for a complex indel in intron 1 of the MLPH gene that was completely associated with the coat colour phenotype (θ = 0.00; LOD = 4.82). Then, we sequenced 6357 bp of the MLPH gene in 18 rabbits of different coat colours, including blue animals. A total of 165 polymorphisms were identified: 137 were in non-coding regions and 28 were in coding exons. One of them was a frameshift deletion in exon 5. Genotyping the half-sib families confirmed the complete cosegregation of this mutation with the blue coat colour. The mutation was analysed in 198 rabbits of 23 breeds. All Blue Vienna and all other blue/grey/ash rabbits in other breeds (Californian, Castor Rex, Checkered Giant, English Spot, Fairy Marburg and Fairy Pearly) were homozygous for this deletion. The identification of MLPH as the responsible gene for the dilute locus in rabbit provides a natural animal model for human Griscelli syndrome type 3 and a new mutant to study the role of this gene on pigmentation.

  12. Monitoring coral bleaching using a colour reference card

    NASA Astrophysics Data System (ADS)

    Siebeck, U. E.; Marshall, N. J.; Klüter, A.; Hoegh-Guldberg, Ove

    2006-08-01

    Assessment of the extent of coral bleaching has become an important part of studies that aim to understand the condition of coral reefs. In this study a reference card that uses differences in coral colour was developed as an inexpensive, rapid and non-invasive method for the assessment of bleaching. The card uses a 6 point brightness/saturation scale within four colour hues to record changes in bleaching state. Changes on the scale of 2 units or more reflect a change in symbiont density and chlorophyll a content, and therefore the bleaching state of the coral. When used by non-specialist observers in the field (here on an intertidal reef flat), there was an inter-observer error of ± 1 colour score. This technique improves on existing subjective assessment of bleaching state by visual observation and offers the potential for rapid, wide-area assessment of changing coral condition.

  13. Can colours be used to segment words when reading?

    PubMed

    Perea, Manuel; Tejero, Pilar; Winskel, Heather

    2015-07-01

    Rayner, Fischer, and Pollatsek (1998, Vision Research) demonstrated that reading unspaced text in Indo-European languages produces a substantial reading cost in word identification (as deduced from an increased word-frequency effect on target words embedded in the unspaced vs. spaced sentences) and in eye movement guidance (as deduced from landing sites closer to the beginning of the words in unspaced sentences). However, the addition of spaces between words comes with a cost: nearby words may fall outside high-acuity central vision, thus reducing the potential benefits of parafoveal processing. In the present experiment, we introduced a salient visual cue intended to facilitate the process of word segmentation without compromising visual acuity: each alternating word was printed in a different colour (i.e., ). Results only revealed a small reading cost of unspaced alternating colour sentences relative to the spaced sentences. Thus, present data are a demonstration that colour can be useful to segment words for readers of spaced orthographies.

  14. Colour based fire detection method with temporal intensity variation filtration

    NASA Astrophysics Data System (ADS)

    Trambitckii, K.; Anding, K.; Musalimov, V.; Linß, G.

    2015-02-01

    Development of video, computing technologies and computer vision gives a possibility of automatic fire detection on video information. Under that project different algorithms was implemented to find more efficient way of fire detection. In that article colour based fire detection algorithm is described. But it is not enough to use only colour information to detect fire properly. The main reason of this is that in the shooting conditions may be a lot of things having colour similar to fire. A temporary intensity variation of pixels is used to separate them from the fire. These variations are averaged over the series of several frames. This algorithm shows robust work and was realised as a computer program by using of the OpenCV library.

  15. Colorimetry and prime colours--a theorem.

    PubMed

    Hornaes, Hans Petter; Wold, Jan Henrik; Farup, Ivar

    2005-08-01

    Human colour vision is the result of a complex process involving topics ranging from physics of light to perception. Whereas the diversity of light entering the eye in principle span an infinite-dimensional vector space in terms of the spectral power distributions, the space of human colour perceptions is three dimensional. One important consequence of this is that a variety of colours can be visually matched by a mixture of only three adequately chosen reference lights. It has been observed that there exists one particular set of monochromatic reference lights that, according to a certain definition, is optimal for producing colour matches. These reference lights are commonly denoted prime colours. In the present paper, we intend to rigorously show that the existence of prime colours is not particular to the human visual system as sometimes stated, but rather an algebraic consequence of the manner in which a kind of colorimetric functions called colour-matching functions are defined and transformed. The solution is based on maximisation of a determinant determining the gamut size of the colour space spanned by the prime colours. Cramer's rule for solving a set of linear equations is an essential part of the proof. By means of examples, it is shown that mathematically the optimal set of reference lights is not unique in general, and that the existence of a maximum determinant is not a necessary condition for the existence of prime colours.

  16. The AMBEGUJAS phenomenon and colour constancy.

    PubMed

    Bergström, Sten Sture

    2004-01-01

    The AMBEGUJAS phenomenon is a reversible flat figure that is spontaneously shifting between two apparent 3-D shapes-'tile' and 'roof'. 2-D perceptions have very rarely been reported. Tied to the shifts between the tile and roof shapes are remarkable changes of perceived colour. In our example, the tile appears to have orange (top half) and blue-green (bottom half) surface colours in white light. The roof appears grey but in an orange illumination and with a blue-green shadow. This phenomenon appears whether a grey display is presented in two coloured illuminations, or a chromatic display with two surface colours (orange and blue-green) is presented in white light. In the coloured illuminations the tile is an example of non-constancy, since its colours are non-veridical colour perceptions. The centre stripe of the display appears to have the same orange and blue-green colours as the lateral stripes but in a shadow. This seems like a colour constancy in a non-constancy situation. An alternative to the classical definition of colour constancy is discussed.

  17. 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. PMID:26736928

  18. Composition of pigments and colour changes in green table olives related to processing type.

    PubMed

    Ramírez, Eva; Gandul-Rojas, Beatriz; Romero, Concepción; Brenes, Manuel; Gallardo-Guerrero, Lourdes

    2015-01-01

    Brownish colourations in Natural green table olives (non-treated with alkali) make this product less attractive to consumers than Spanish-style green table olives (treated with alkali), which develop a more appreciated bright golden-yellow colour. These colour differences were studied in relation to changes in the composition of chlorophyll and carotenoid pigments, as well as polyphenolic compounds and polyphenol oxidase enzyme (PPO) activity. Natural green olives showed a different chlorophyll profile than Spanish-style. However, all the chlorophyll pigments formed in both processing types were Mg-free derivatives (mostly pheophytins) with similar colourations, ranging from grey to green brownish. In the carotenoid fraction no appreciable differences were found between both processing types. The fruit's brownish colour was mainly due to polymeric substances with a size of >1000 daltons and polyphenolic nature, resulting from an enzymatic oxidation by PPO of the o-diphenolic compounds present in the fresh fruits.

  19. Variable-rate colour image quantization based on quadtree segmentation

    NASA Astrophysics Data System (ADS)

    Hu, Y. C.; Li, C. Y.; Chuang, J. C.; Lo, C. C.

    2011-09-01

    A novel variable-sized block encoding with threshold control for colour image quantization (CIQ) is presented in this paper. In CIQ, the colour palette used has a great influence on the reconstructed image quality. Typically, a higher image quality and a larger storage cost are obtained when a larger-sized palette is used in CIQ. To cut down the storage cost while preserving quality of the reconstructed images, the threshold control policy for quadtree segmentation is used in this paper. Experimental results show that the proposed method adaptively provides desired bit rates while having better image qualities comparing to CIQ with the usage of multiple palettes of different sizes.

  20. 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.

  1. Effects of thermal treatment on chemical, mechanical and colour traits in Norway spruce wood.

    PubMed

    Kačíková, Danica; Kačík, František; Cabalová, Iveta; Durkovič, Jaroslav

    2013-09-01

    In several different branches of the wood industry heat treatment is a growing application as it changes the chemical, mechanical, physical and biological properties of wood. Investigations using wet chemical analyses, Fourier transform infrared spectroscopy, size exclusion chromatography, and CIELab colour system have been conducted to study the changes in Norway spruce wood subjected to temperature up to 270°C over a 30 min time period. The results showed that mass loss (ML), total crystallinity index (TCI) of cellulose, total colour difference (ΔE*), and the content of lignin and extractives increased with the temperature, whereas degree of polymerization (DP) of cellulose, modulus of rupture (MOR), modulus of elasticity (MOE), lightness difference (ΔL*), and the content of holocellulose, cellulose and hemicelluloses all decreased with the thermal treatment. Relationships between temperature and the examined wood traits were all fitted by exponential curves. Power law relationships were found to fit the trends for DP of cellulose with ΔE*, ΔL*, and TCI of cellulose. Also found were power law regressions for the content of hemicelluloses with MOE, MOR, ΔL*, and ML. Temperatures ranging from 20 to 187°C formed a compact cluster, clearly separated from the higher examined temperatures in the multivariate wood trait space.

  2. Profile detection by projection of coloured patterns

    NASA Astrophysics Data System (ADS)

    Fontani, Daniela; Francini, Franco; Sansoni, Paola; Jafrancesco, David; Mercatelli, Luca

    2007-06-01

    The paper presents a study to detect the three-dimensional profile of an object using a technique based on the projection of colour-coded lines. The accessibility at low-cost of projectors and digital photographic cameras has approved the employment and the development of these techniques. They provide information concerning the profile through the acquisition of a couple of images. The first one concerns a reference plane and it is captured only once, while the second one refers to the object image. The proposed methodology simplifies the individuation of homologous lines within the two images, when grating projection techniques are employed. Even though these methods are conceptually very simple, they are rarely applied because of this difficulty in stating the correspondence between observed deformation and projected line. The attribution of a different colour to every single line, or to a set of them, introduces an element useful for their selection. After the image acquisition, the data pertaining to the profile are extracted examining the image by means of an algorithm developed in Matlab language for this application. The research work is in progress beyond the results presented in this paper, which already represent a excellent starting point for further studies and evolutions of the technique.

  3. Colour agnosia impairs the recognition of natural but not of non-natural scenes.

    PubMed

    Nijboer, Tanja C W; Van Der Smagt, Maarten J; Van Zandvoort, Martine J E; De Haan, Edward H F

    2007-03-01

    Scene recognition can be enhanced by appropriate colour information, yet the level of visual processing at which colour exerts its effects is still unclear. It has been suggested that colour supports low-level sensory processing, while others have claimed that colour information aids semantic categorization and recognition of objects and scenes. We investigated the effect of colour on scene recognition in a case of colour agnosia, M.A.H. In a scene identification task, participants had to name images of natural or non-natural scenes in six different formats. Irrespective of scene format, M.A.H. was much slower on the natural than on the non-natural scenes. As expected, neither M.A.H. nor control participants showed any difference in performance for the non-natural scenes. However, for the natural scenes, appropriate colour facilitated scene recognition in control participants (i.e., shorter reaction times), whereas M.A.H.'s performance did not differ across formats. Our data thus support the hypothesis that the effect of colour occurs at the level of learned associations.

  4. Colour vision and background adaptation in a passerine bird, the zebra finch (Taeniopygia guttata)

    PubMed Central

    2016-01-01

    Today, there is good knowledge of the physiological basis of bird colour vision and how mathematical models can be used to predict visual thresholds. However, we still know only little about how colour vision changes between different viewing conditions. This limits the understanding of how colour signalling is configured in habitats where the light of the illumination and the background may shift dramatically. I examined how colour discrimination in zebra finch (Taeniopygia guttata) is affected by adaptation to different backgrounds. I trained finches in a two-alternative choice task, to choose between red discs displayed on backgrounds with different colours. I found that discrimination thresholds correlate with stimulus contrast to the background. Thresholds are low, and in agreement with model predictions, for a background with a red colour similar to the discs. For the most contrasting green background, thresholds are about five times higher than this. Subsequently, I trained the finches for the detection of single discs on a grey background. Detection thresholds are about 2.5 to 3 times higher than discrimination thresholds. This study demonstrates close similarities in human and bird colour vision, and the quantitative data offer a new possibility to account for shifting viewing conditions in colour vision models. PMID:27703702

  5. Coevolution and the adaptive value of autumn tree colours: colour preference and growth rates of a southern beech aphid.

    PubMed

    Ramírez, C C; Lavandero, B; Archetti, M

    2008-01-01

    The evolutionary explanation for the change in leaf colour during autumn is still debated. Autumn colours could be a signal of defensive commitment towards insects (coevolution) or an adaptation against physical damage because of light at low temperatures (photoprotection). These two hypotheses have different predictions: (1) under the coevolution hypothesis, insects should not prefer red leaves in autumn and grow better in spring on trees with green autumn leaves; and (2) under the photoprotection hypothesis, insects should prefer and grow better on trees with red leaves because they provide better nutrition. Studying colour preference in autumn and growth rates in spring of a southern beech aphid species (Neuquenaphis staryi) on Nothofagus alessandrii, we found preference for green leaves in autumn but no differential performance of aphids in spring. We suggest that aphid preference for green might have evolved to exploit better their host during the autumn rather than to improve their performance in spring.

  6. Normal values for 24-h urinary protein excretion: total and low molecular weight proteins with a sex-related difference.

    PubMed

    Kawakami, H; Murakami, T; Kajii, T

    1990-05-01

    Urinary excretion of total and low molecular weight (LMW) (less than 40,000) proteins for a 24-h period was determined in 60 normal individuals, 30 men and 30 women, aged 21 to 44 years. 24-h urinary total protein excretion in men was 91.2 +/- 25.1 mg (mean +/- SD) (range: 40.2-146.8 mg), while that in women was 62.5 +/- 23.6 mg (range: 28.4-130.9 mg), as measured by a biuret method using bicinchoninic acid as a reagent. 24-h urinary LMW protein excretion in men was 37.3 +/- 13.6 mg (range: 12.7-62.7 mg), while that in women was 23.2 +/- 11.8 mg (range: 7.2-54.2 mg), as estimated by sodium dodecylsulfate-polyacrylamide gel electrophoresis of concentrated urine samples. Thus, a significantly higher (t-test, p less than 0.01) excretion of both the total and LMW proteins was found in men than in women. However, the percentage of the LMW proteins among the total proteins did not differ between the sexes: 40.3 +/- 7.5% (range: 21.7-54.9%) for men and 36.5 +/- 9.9% (range: 20.1-56.7%) for women.

  7. 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.

  8. Colour Consideration for Waiting areas in hospitals

    NASA Astrophysics Data System (ADS)

    Zraati, Parisa

    2012-08-01

    Colour is one the most important factors in the nature that can have some affects on human behaviour. Many years ago, it was proven that using colour in public place can have some affect on the users. Depend of the darkness and lightness; it can be vary from positive to negative. The research will mainly focus on the colour and psychological influences and physical factors. The statement of problem in this research is what is impact of colour usually applied to waiting area? The overall aim of the study is to explore the visual environment of hospitals and to manage the colour psychological effect of the hospital users in the waiting area by creating a comfortable, pleasant and cozy environment for users while spend their time in waiting areas. The analysisconcentrate on satisfaction and their interesting regarding applied colour in two private hospital waiting area in Malaysia.

  9. Practice and Colour-Word Integration in Stroop Interference

    ERIC Educational Resources Information Center

    Gul, Amara; Humphreys, Glyn W.

    2015-01-01

    Congruency effects were examined using a manual response version of the Stroop task in which the relationship between the colour word and its hue on incongruent trials was either kept constant or varied randomly across different pairings within the stimulus set. Congruency effects were increased in the condition where the incongruent hue-word…

  10. Quantitative Monitoring for Enhanced Geothermal Systems Using Double-Difference Waveform Inversion with Spatially-Variant Total-Variation Regularization

    SciTech Connect

    Lin, Youzuo; Huang, Lianjie; Zhang, Zhigang

    2011-01-01

    Double-difference waveform inversion is a promising tool for quantitative monitoring for enhanced geothermal systems (EGS). The method uses time-lapse seismic data to jointly inverts for reservoir changes. Due to the ill-posedness of waveform inversion, it is a great challenge to obtain reservoir changes accurately and efficiently, particularly when using timelapse seismic reflection data. To improve reconstruction, we develop a spatially-variant total-variation regularization scheme into double-difference waveform inversion to improve the inversion accuracy and robustness. The new regularization scheme employs different regularization parameters in different regions of the model to obtain an optimal regularization in each area. We compare the results obtained using a spatially-variant parameter with those obtained using a constant regularization parameter. Utilizing a spatially-variant regularization scheme, the target monitoring regions are well reconstructed and the image noise is significantly reduced outside the monitoring regions. Our numerical examples demonstrate that the spatially-variant total-variation regularization scheme provides the flexibility to regularize local regions based on the a priori spatial information without increasing computational costs and the computer memory requirement.

  11. Colour vision deficiency and physics teaching

    NASA Astrophysics Data System (ADS)

    Maule, Louise; Featonby, David

    2016-05-01

    1 in 12 males suffer from some form of colour vision deficiency (CVD) which in the present colour dominated world of education presentation can be a severe disadvantage. Although aware of ‘colourblindness’ most teachers make little or no adjustment for these pupils for whom tasks may be more difficult. This article examines colour vision deficiency and looks at ways in which we can help the many students who have this problem.

  12. Quantification of differences between occupancy and total monitoring periods for better assessment of exposure to particles in indoor environments

    NASA Astrophysics Data System (ADS)

    Wierzbicka, A.; Bohgard, M.; Pagels, J. H.; Dahl, A.; Löndahl, J.; Hussein, T.; Swietlicki, E.; Gudmundsson, A.

    2015-04-01

    For the assessment of personal exposure, information about the concentration of pollutants when people are in given indoor environments (occupancy time) are of prime importance. However this kind of data frequently is not reported. The aim of this study was to assess differences in particle characteristics between occupancy time and the total monitoring period, with the latter being the most frequently used averaging time in the published data. Seven indoor environments were selected in Sweden and Finland: an apartment, two houses, two schools, a supermarket, and a restaurant. They were assessed for particle number and mass concentrations and number size distributions. The measurements using a Scanning Mobility Particle Sizer and two photometers were conducted for seven consecutive days during winter in each location. Particle concentrations in residences and schools were, as expected, the highest during occupancy time. In the apartment average and median PM2.5 mass concentrations during the occupancy time were 29% and 17% higher, respectively compared to total monitoring period. In both schools, the average and medium values of the PM2.5 mass concentrations were on average higher during teaching hours compared to the total monitoring period by 16% and 32%, respectively. When it comes to particle number concentrations (PNC), in the apartment during occupancy, the average and median values were 33% and 58% higher, respectively than during the total monitoring period. In both houses and schools the average and median PNC were similar for the occupancy and total monitoring periods. General conclusions on the basis of measurements in the limited number of indoor environments cannot be drawn. However the results confirm a strong dependence on type and frequency of indoor activities that generate particles and site specificity. The results also indicate that the exclusion of data series during non-occupancy periods can improve the estimates of particle concentrations and

  13. Colour vision and response bias in a coral reef fish.

    PubMed

    Cheney, Karen L; Newport, Cait; McClure, Eva C; Marshall, N Justin

    2013-08-01

    Animals use coloured signals for a variety of communication purposes, including to attract potential mates, recognize individuals, defend territories and warn predators of secondary defences (aposematism). To understand the mechanisms that drive the evolution and design of such visual signals, it is important to understand the visual systems and potential response biases of signal receivers. Here, we provide raw data on the spectral capabilities of a coral reef fish, the Picasso triggerfish Rhinecanthus aculeatus, which is potentially trichromatic with three cone sensitivities of 413 nm (single cone), 480 nm (double cone, medium sensitivity) and 528 nm (double cone, long sensitivity), and a rod sensitivity of 498 nm. The ocular media have a 50% transmission cut off at 405 nm. Behavioural experiments confirmed colour vision over their spectral range; triggerfish were significantly more likely to choose coloured stimuli over grey distractors, irrespective of luminance. We then examined whether response biases existed towards coloured and patterned stimuli to provide insight into how visual signals - in particular, aposematic colouration - may evolve. Triggerfish showed a preferential foraging response bias to red and green stimuli, in contrast to blue and yellow, irrespective of pattern. There was no response bias to patterned over monochromatic non-patterned stimuli. A foraging response bias towards red in fish differs from that of avian predators, who often avoid red food items. Red is frequently associated with warning colouration in terrestrial environments (ladybirds, snakes, frogs), whilst blue is used in aquatic environments (blue-ringed octopus, nudibranchs); whether the design of warning (aposematic) displays is a cause or consequence of response biases is unclear.

  14. Colour vision and response bias in a coral reef fish.

    PubMed

    Cheney, Karen L; Newport, Cait; McClure, Eva C; Marshall, N Justin

    2013-08-01

    Animals use coloured signals for a variety of communication purposes, including to attract potential mates, recognize individuals, defend territories and warn predators of secondary defences (aposematism). To understand the mechanisms that drive the evolution and design of such visual signals, it is important to understand the visual systems and potential response biases of signal receivers. Here, we provide raw data on the spectral capabilities of a coral reef fish, the Picasso triggerfish Rhinecanthus aculeatus, which is potentially trichromatic with three cone sensitivities of 413 nm (single cone), 480 nm (double cone, medium sensitivity) and 528 nm (double cone, long sensitivity), and a rod sensitivity of 498 nm. The ocular media have a 50% transmission cut off at 405 nm. Behavioural experiments confirmed colour vision over their spectral range; triggerfish were significantly more likely to choose coloured stimuli over grey distractors, irrespective of luminance. We then examined whether response biases existed towards coloured and patterned stimuli to provide insight into how visual signals - in particular, aposematic colouration - may evolve. Triggerfish showed a preferential foraging response bias to red and green stimuli, in contrast to blue and yellow, irrespective of pattern. There was no response bias to patterned over monochromatic non-patterned stimuli. A foraging response bias towards red in fish differs from that of avian predators, who often avoid red food items. Red is frequently associated with warning colouration in terrestrial environments (ladybirds, snakes, frogs), whilst blue is used in aquatic environments (blue-ringed octopus, nudibranchs); whether the design of warning (aposematic) displays is a cause or consequence of response biases is unclear. PMID:23580729

  15. Calibrating screens for continuous colour displays.

    PubMed

    Shepherd, A J

    1997-01-01

    This paper focuses on two issues that are important to those who use colour monitors for research in vision. One is concerned with the measurement and calibration of colour screens. To this end the luminance and chromaticity readings of a tri-filter colorimeter and a spectroradiometer are compared (both commonly used to calibrate screens). The second is concerned with screen interactions, whereby colours can be distorted from their expected or calculated values by the colours displayed in neighbouring areas. This issue is crucial for those who use measurements of the light emitted from the red, green and blue phosphors of a monitor in isolation to specify other colours on screen, particularly in the research areas of colour contrast and colour constancy, since the specified colours may not actually be displayed. Finally, an alternative calibration method is described that uses an iterative measurement procedure to obtain screen specifications that are accurate regardless of the display complexity, so that researchers can be confident that the required colours are actually displayed on the screen.

  16. Evidence against functionalism from neuroimaging of the alien colour effect in synaesthesia.

    PubMed

    Gray, Jeffrey A; Parslow, David M; Brammer, Michael J; Chopping, Susan; Vythelingum, Goparlen N; ffytche, Dominic H

    2006-02-01

    Coloured hearing synaesthetes experience colours to heard words, as confirmed by reliability of self-report, psychophysical testing and functional neuroimaging data. Some also describe the 'alien colour effect' (ACE): in response to colour names, they experience colours different from those named. We have previously reported that the ACE slows colour naming in a Stroop task, reflecting cognitive interference from synaesthetically induced colours, which depends upon their being consciously experienced. It has been proposed that the hippocampus mediates such consciously experienced conflict. Consistent with this hypothesis, we now report that, in functional magnetic resonance imaging of the Stroop task, hippocampal activation differentiates synaesthetes with the ACE from those without it and from non-synaesthete controls. These findings confirm the reality of coloured hearing synaesthesia and the ACE, phenomena which pose major challenges to the dominant contemporary account of mental states, functionalism. Reductive functionalism identifies types of mental states with causal roles: relations to inputs, outputs and other states. However, conscious mental states, such as experiences of colour, are distinguished by their qualitative properties or qualia. If functionalism is applied to conscious mental states, it identifies the qualitative type of an experience with its causal role or function. This entails both that experiences with disparate qualitative properties cannot have the same functional properties, and that experiences with disparate functional properties cannot have the same qualitative properties. Challenges to functionalism have often denied the first entailment. Here, we challenge the second entailment on empirical grounds. In coloured hearing synaesthesia, colour qualia are associated with both hearing words and seeing surfaces; and, in the ACE, these two functions act in opposition to one another. Whatever its merits as an account of other mental states

  17. Regional Ocean Colour Remote Sensing Algorithm for the Baltic Sea

    NASA Astrophysics Data System (ADS)

    Hieronymi, Martin; Muller, Dagmar; Krasemann, Hajo; Schonfeld, Wolfgang; Rottgers, Rudiger; Doerffer, Roland

    2015-12-01

    The Baltic Sea is a challenging study site from an optically point of view. Its partly highly absorbing waters are mainly associated with the presence of coloured dissolved organic matter and often accompanied by non-algae absorbing particles. In addition, the Baltic Sea area is characterised by massive annual surface blooms of cyanobacteria. In Europe, the Baltic Sea is a very specific and important case study with intense user interest. In the framework of different research projects as the “Ocean Colour Climate Change Initiative”, the “SEOM OC Extreme Case 2 Waters”, and partly “MyOcean”, we aim to develop an optimised, error-characterised, regional ocean colour processor applicable to several satellite sensors, like MODIS, MERIS, VIIRS, and OLCI. The procedure, which is used to determine inherent optical properties and different water constituents’ concentrations from remote sensing reflectance, is an artificial Neural Network (NN). We provide first results of comparisons of in-situ data with different ocean colour products.

  18. Effect of tea, coffee and turmeric solutions on the colour of denture base acrylic resin: an in vitro study.

    PubMed

    Singh, S V; Aggarwal, Priyanki

    2012-09-01

    Discoloration of acrylic resin denture base when it comes in contact with various food materials and beverages in the oral cavity may cause aesthetic concern to a denture wearer. The objective of this study was to evaluate the effect of tea, coffee and turmeric solutions on the colour of different brands of heat cure acrylic resin denture base materials commonly used in India. Spectrophotometer was used to evaluate the colour change. A significant difference was found when change in colour was statistically analysed.

  19. The proton temperature and the total hourly variance of the magnetic field components in different solar wind speed regions

    NASA Technical Reports Server (NTRS)

    Tu, Chuan-Yi; Freeman, John W.; Lopez, R. E.

    1989-01-01

    A comparison has been made between the predictions of the theory for radial variations of both Alfvenic fluctuations and solar wind proton temperatures proposed by Tu (1987, 1988) and the statistical results of hourly averaged plasma and magnetic field data observed by Helios 1 and 2 from launch through 1980 for different solar wind speed regimes. The comparison shows that for speed ranges between 500-800 km/s, the radial variation of the proton temperature between 0.3 and 1 AU can be explained by heating from the cascade energy which is determined by the radial variation of the total variance of magnetic field vector.

  20. Robust colour calibration of an imaging system using a colour space transform and advanced regression modelling.

    PubMed

    Jackman, Patrick; Sun, Da-Wen; Elmasry, Gamal

    2012-08-01

    A new algorithm for the conversion of device dependent RGB colour data into device independent L*a*b* colour data without introducing noticeable error has been developed. By combining a linear colour space transform and advanced multiple regression methodologies it was possible to predict L*a*b* colour data with less than 2.2 colour units of error (CIE 1976). By transforming the red, green and blue colour components into new variables that better reflect the structure of the L*a*b* colour space, a low colour calibration error was immediately achieved (ΔE(CAL) = 14.1). Application of a range of regression models on the data further reduced the colour calibration error substantially (multilinear regression ΔE(CAL) = 5.4; response surface ΔE(CAL) = 2.9; PLSR ΔE(CAL) = 2.6; LASSO regression ΔE(CAL) = 2.1). Only the PLSR models deteriorated substantially under cross validation. The algorithm is adaptable and can be easily recalibrated to any working computer vision system. The algorithm was tested on a typical working laboratory computer vision system and delivered only a very marginal loss of colour information ΔE(CAL) = 2.35. Colour features derived on this system were able to safely discriminate between three classes of ham with 100% correct classification whereas colour features measured on a conventional colourimeter were not.

  1. Analyses of Total Alkaloid Extract of Corydalis yanhusuo by Comprehensive RP × RP Liquid Chromatography with pH Difference

    PubMed Central

    Shen, Hongling; Wang, Lijun

    2016-01-01

    A comprehensive two-dimensional (2D) reverse phase (RP) liquid chromatography (LC) method is developed for alkaloid analysis. This offline comprehensive 2D method is developed using different pH values. With a pH value of 10.5, most alkaloids appear in the form of neutral molecules possessing high retention factors based on their polarity, while the alkaloid polarity order is changed when the pH value decreased to 3.0. The performance of pH modulated 2D LC is demonstrated with 8 alkaloid standards which resulted in orthogonal separation. The developed method is then applied to total alkaloid separation in Corydalis yanhusuo. The first-dimension separation is carried out using methanol and water containing 1.0% ammonium hydroxide and a strong base-resistant RP column, which afforded a peak capacity of 94. The second-dimension analysis is carried out with a surface positive charge column providing a peak capacity of 205 using a mobile phase consisting of acetonitrile and water with 0.15% formic acid. 2D analyses of total alkaloid extract from C. yanhusuo afford a total peak capacity of 9090. Sixteen compounds were tentatively identified based on their ultraviolet spectrum and MS/MS analyses. The proposed method provides an alternative approach to achieve high peak capacity for analysis of alkaloid extract. PMID:27722008

  2. Testosterone-Induced Expression of Male Colour Morphs in Females of the Polymorphic Tawny Dragon Lizard, Ctenophorus decresii.

    PubMed

    Rankin, Katrina; Stuart-Fox, Devi

    2015-01-01

    Many colour polymorphisms are present only in one sex, usually males, but proximate mechanisms controlling the expression of sex-limited colour polymorphisms have received little attention. Here, we test the hypothesis that artificial elevation of testosterone in females of the colour polymorphic tawny dragon lizard, Ctenophorus decresii, can induce them to express the same colour morphs, in similar frequencies, to those found in males. Male C. decresii, express four discrete throat colour morphs (orange, yellow, grey and an orange central patch surrounded by yellow). We used silastic implants to experimentally elevate testosterone levels in mature females to induce colour expression. Testosterone elevation resulted in a substantial increase in the proportion and intensity of orange but not yellow colouration, which was present in a subset of females prior to treatment. Consequently, females exhibited the same set of colour morphs as males, and we confirmed that these morphs are objectively classifiable, by using digital image analyses and spectral reflectance measurements, and occur in similar frequencies as in males. These results indicate that the influence of testosterone differs for different colours, suggesting that their expression may be governed by different proximate hormonal mechanisms. Thus, caution must be exercised when using artificial testosterone manipulation to induce female expression of sex-limited colour polymorphisms. Nevertheless, the ability to express sex-limited colours (in this case orange) to reveal the same, objectively classifiable morphs in similar frequencies to males suggests autosomal rather than sex-linked inheritance, and can facilitate further research on the genetic basis of colour polymorphism, including estimating heritability and selection on colour morphs from pedigree data. PMID:26485705

  3. Testosterone-Induced Expression of Male Colour Morphs in Females of the Polymorphic Tawny Dragon Lizard, Ctenophorus decresii.

    PubMed

    Rankin, Katrina; Stuart-Fox, Devi

    2015-01-01

    Many colour polymorphisms are present only in one sex, usually males, but proximate mechanisms controlling the expression of sex-limited colour polymorphisms have received little attention. Here, we test the hypothesis that artificial elevation of testosterone in females of the colour polymorphic tawny dragon lizard, Ctenophorus decresii, can induce them to express the same colour morphs, in similar frequencies, to those found in males. Male C. decresii, express four discrete throat colour morphs (orange, yellow, grey and an orange central patch surrounded by yellow). We used silastic implants to experimentally elevate testosterone levels in mature females to induce colour expression. Testosterone elevation resulted in a substantial increase in the proportion and intensity of orange but not yellow colouration, which was present in a subset of females prior to treatment. Consequently, females exhibited the same set of colour morphs as males, and we confirmed that these morphs are objectively classifiable, by using digital image analyses and spectral reflectance measurements, and occur in similar frequencies as in males. These results indicate that the influence of testosterone differs for different colours, suggesting that their expression may be governed by different proximate hormonal mechanisms. Thus, caution must be exercised when using artificial testosterone manipulation to induce female expression of sex-limited colour polymorphisms. Nevertheless, the ability to express sex-limited colours (in this case orange) to reveal the same, objectively classifiable morphs in similar frequencies to males suggests autosomal rather than sex-linked inheritance, and can facilitate further research on the genetic basis of colour polymorphism, including estimating heritability and selection on colour morphs from pedigree data.

  4. Testosterone-Induced Expression of Male Colour Morphs in Females of the Polymorphic Tawny Dragon Lizard, Ctenophorus decresii

    PubMed Central

    Rankin, Katrina; Stuart-Fox, Devi

    2015-01-01

    Many colour polymorphisms are present only in one sex, usually males, but proximate mechanisms controlling the expression of sex-limited colour polymorphisms have received little attention. Here, we test the hypothesis that artificial elevation of testosterone in females of the colour polymorphic tawny dragon lizard, Ctenophorus decresii, can induce them to express the same colour morphs, in similar frequencies, to those found in males. Male C. decresii, express four discrete throat colour morphs (orange, yellow, grey and an orange central patch surrounded by yellow). We used silastic implants to experimentally elevate testosterone levels in mature females to induce colour expression. Testosterone elevation resulted in a substantial increase in the proportion and intensity of orange but not yellow colouration, which was present in a subset of females prior to treatment. Consequently, females exhibited the same set of colour morphs as males, and we confirmed that these morphs are objectively classifiable, by using digital image analyses and spectral reflectance measurements, and occur in similar frequencies as in males. These results indicate that the influence of testosterone differs for different colours, suggesting that their expression may be governed by different proximate hormonal mechanisms. Thus, caution must be exercised when using artificial testosterone manipulation to induce female expression of sex-limited colour polymorphisms. Nevertheless, the ability to express sex-limited colours (in this case orange) to reveal the same, objectively classifiable morphs in similar frequencies to males suggests autosomal rather than sex-linked inheritance, and can facilitate further research on the genetic basis of colour polymorphism, including estimating heritability and selection on colour morphs from pedigree data. PMID:26485705

  5. Effect of different post-feeding intervals on the total time of development of the blowfly Lucilia sericata (Diptera: Calliphoridae).

    PubMed

    Mai, Madeleine; Amendt, Jens

    2012-09-10

    By estimating the age of the immature stages of flies developing on a corpse, forensic entomologists are able to establish the minimum post-mortem interval. Blowflies, which are the first and most important colonizers, usually leave the cadaver at the end of the last larval stage searching for a pupation site. This period of development is referred as the post-feeding or wandering stage. The characteristics of the ground where the corpse was placed might be of notable importance for the post-feeding dispersal time: For pupariation the larvae prefer an environment protected from light and predators and may have a longer dispersal time in order to reach an appropriate pupation site. Hence, the dispersal time can vary and may influence the total time of development which may lead to an erroneous calculation of the post-mortem interval. This study investigates the effect of various post-feeding time intervals on the development of the blowfly Lucilia sericata at a temperature of 25°C. As larvae reached the post-feeding stage a pupariation substrate was offered at 0 and after 12, 24 and 48h. Only the larvae with a dispersal time of 24h (total time of development 325.2h; median) and 48h (total time of development 347.7h; median) showed a significantly longer total development time compared to the control group (total time of development 318.4h; median). The mortality rate did not differ between groups; however the flies that emerged from the group with a dispersal of 48h were significantly smaller indicating increased energy consumption during dispersal. The results of this study indicate that a prolonged post-feeding stage could increase the total developmental time of L. sericata which should be taken into consideration when interpreting entomological findings. The need for a serious examination of current rearing practices in forensic entomology laboratories is indicated because reference data sets for the time of development are usually produced by offering the post

  6. Effect of different post-feeding intervals on the total time of development of the blowfly Lucilia sericata (Diptera: Calliphoridae).

    PubMed

    Mai, Madeleine; Amendt, Jens

    2012-09-10

    By estimating the age of the immature stages of flies developing on a corpse, forensic entomologists are able to establish the minimum post-mortem interval. Blowflies, which are the first and most important colonizers, usually leave the cadaver at the end of the last larval stage searching for a pupation site. This period of development is referred as the post-feeding or wandering stage. The characteristics of the ground where the corpse was placed might be of notable importance for the post-feeding dispersal time: For pupariation the larvae prefer an environment protected from light and predators and may have a longer dispersal time in order to reach an appropriate pupation site. Hence, the dispersal time can vary and may influence the total time of development which may lead to an erroneous calculation of the post-mortem interval. This study investigates the effect of various post-feeding time intervals on the development of the blowfly Lucilia sericata at a temperature of 25°C. As larvae reached the post-feeding stage a pupariation substrate was offered at 0 and after 12, 24 and 48h. Only the larvae with a dispersal time of 24h (total time of development 325.2h; median) and 48h (total time of development 347.7h; median) showed a significantly longer total development time compared to the control group (total time of development 318.4h; median). The mortality rate did not differ between groups; however the flies that emerged from the group with a dispersal of 48h were significantly smaller indicating increased energy consumption during dispersal. The results of this study indicate that a prolonged post-feeding stage could increase the total developmental time of L. sericata which should be taken into consideration when interpreting entomological findings. The need for a serious examination of current rearing practices in forensic entomology laboratories is indicated because reference data sets for the time of development are usually produced by offering the post

  7. Male-male competition and nuptial-colour displacement as a diversifying force in Lake Victoria cichlid fishes.

    PubMed

    Seehausen, Ole; Schluter, Dolph

    2004-07-01

    We propose a new mechanism for diversification of male nuptial-colour patterns in the rapidly speciating cichlid fishes of Lake Victoria. Sympatric closely related species often display nuptial colours at opposite ends of the spectrum with males either blue or yellow to red. Colour polymorphisms within single populations are common too. We propose that competition between males for breeding sites promotes such colour diversification, and thereby speciation. We hypothesize that male aggression is primarily directed towards males of the common colour, and that rare colour morphs enjoy a negatively frequency-dependent fitness advantage. We test our hypothesis with a large dataset on the distributions and nuptial colorations of 52 species on 47 habitat islands in Lake Victoria, and with a smaller dataset on the within-spawning-site distributions of males with different coloration. We report that territories of males of the same colour are negatively associated on the spawning site, and that the distribution of closely related species over habitat islands is determined by nuptial coloration in the fashion predicted by our hypothesis. Whereas among unrelated species those with similar nuptial colour are positively associated, among closely related species those with similar colour are negatively associated and those with different colour are positively associated. This implies that negatively frequency-dependent selection on nuptial coloration among closely related species is a sufficiently strong force to override other effects on species distributions. We suggest that male-male competition is an important and previously neglected agent of diversification among haplochromine cichlid fishes.

  8. Colorimetric evaluation of iPhone apps for colour vision tests based on the Ishihara test.

    PubMed

    Dain, Stephen J; AlMerdef, Ali

    2016-05-01

    Given the versatility of smart phone displays, it was inevitable that applications (apps) providing colour vision testing would appear as an option. In this study, the colorimetric characteristics of five available iPhone apps for colour vision testing are assessed as a prequel to possible clinical evaluation. The colours of the displays produced by the apps are assessed with reference to the colours of a printed Ishihara test. The visual task is assessed on the basis of the colour differences and the alignment to the dichromatic confusion lines. The apps vary in quality and while some are colorimetrically acceptable, there are also some problems with their construction in making them a clinically useful app rather than curiosity driven self-testing. There is no reason why, in principle, a suitable test cannot be designed for smart phones.

  9. The adaptive significance of ontogenetic colour change in a tropical python.

    PubMed

    Wilson, David; Heinsohn, Robert; Endler, John A

    2007-02-22

    Ontogenetic colour change is typically associated with changes in size, vulnerability or habitat, but assessment of its functional significance requires quantification of the colour signals from the receivers' perspective. The tropical python, Morelia viridis, is an ideal species to establish the functional significance of ontogenetic colour change. Neonates hatch either yellow or red and both the morphs change to green with age. Here, we show that colour change from red or yellow to green provides camouflage from visually oriented avian predators in the different habitats used by juveniles and adults. This reflects changes in foraging behaviour and vulnerability as individuals mature and provides a rare demonstration of the adaptive value of ontogenetic colour change.

  10. Colorimetric evaluation of iPhone apps for colour vision tests based on the Ishihara test.

    PubMed

    Dain, Stephen J; AlMerdef, Ali

    2016-05-01

    Given the versatility of smart phone displays, it was inevitable that applications (apps) providing colour vision testing would appear as an option. In this study, the colorimetric characteristics of five available iPhone apps for colour vision testing are assessed as a prequel to possible clinical evaluation. The colours of the displays produced by the apps are assessed with reference to the colours of a printed Ishihara test. The visual task is assessed on the basis of the colour differences and the alignment to the dichromatic confusion lines. The apps vary in quality and while some are colorimetrically acceptable, there are also some problems with their construction in making them a clinically useful app rather than curiosity driven self-testing. There is no reason why, in principle, a suitable test cannot be designed for smart phones. PMID:27146711

  11. 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.

  12. Carotenoid-based bill colour is an integrative signal of multiple parasite infection in blackbird

    NASA Astrophysics Data System (ADS)

    Biard, Clotilde; Saulnier, Nicolas; Gaillard, Maria; Moreau, Jérôme

    2010-11-01

    In the study of parasite-mediated sexual selection, there has been controversial evidence for the prediction that brighter males should have fewer parasites. Most of these studies have focused on one parasite species. Our aim was to investigate the expression of carotenoid-based coloured signals in relation to patterns of multiple parasite infections, to determine whether colour reflects parasite load of all parasite species, or whether different relationships might be found when looking at each parasite species independently. We investigated the relationship between bill colour, body mass and plasma carotenoids and parasite load (feather chewing lice, blood parasite Plasmodium sp., intestinal parasites cestodes and coccidia) in the blackbird ( Turdus merula). Bill colour on its own appeared to be a poor predictor of parasite load when investigating its relationships with individual parasite species. Variation in parasite intensities at the community level was summarised using principal component analysis to derive synthetic indexes of relative parasite species abundance and absolute parasite load. The relative abundance of parasite species was strongly related to bill colour, plasma carotenoid levels and body mass: birds with relatively more cestodes and chewing lice and relatively less Plasmodium and coccidia had a more colourful bill, circulated more carotenoids and were heavier. These results suggest that bill colour more accurately reflects the relative intensities of parasite infection, rather than one-by-one relationships with parasites or absolute parasite burden. Investigating patterns of multiple parasite infection would thus improve our understanding of the information conveyed by coloured signals on parasite load.

  13. Dynamic application of digital image and colour processing in characterizing flame radiation features

    NASA Astrophysics Data System (ADS)

    Huang, Hua Wei; Zhang, Yang

    2010-08-01

    In this work, the experimental investigation of the dynamic flame properties of flame flickering and equivalence ratio sensing of a combustion process was done. In particular, the time-varied flame properties were examined using a novel digital image and colour processing methodology. This technique makes use of the observed correlation between a digital image colour signal and physical flame radiation characteristics in the visible wavelength domain. Aspects of RGB and HSV colour modelling principles were applied to show that the addition of colour identification in the image processing of high-speed flame image data could yield three useful parameters which are related to the dynamic behaviour of different flame emanating components. First, the validity of the colour identities for tracking the yellowish-red diffusion and greenish-blue premixed flame colourations were examined by comparing their respective flickering frequency profiles. Then, the usefulness of the extracted Rdiffusion, Gpremixed and Bpremixed colour signals to abstractly represent the behaviour of soot, C2* and CH* emission characteristics in a dynamic flame transition from diffusion to stoichiometric premixed condition was demonstrated. In particular, the colour signal ratio Bpremixed/Gpremixed was correlated to exemplify the approximate time-varied state of the equivalence ratio from the imaged combustion phenomenon.

  14. Cost effectiveness of total hip arthroplasty in osteoarthritis: comparison of devices with differing bearing surfaces and modes of fixation.

    PubMed

    Pulikottil-Jacob, R; Connock, M; Kandala, N-B; Mistry, H; Grove, A; Freeman, K; Costa, M; Sutcliffe, P; Clarke, A

    2015-04-01

    Many different designs of total hip arthroplasty (THA) with varying performance and cost are available. The identification of those which are the most cost-effective could allow significant cost-savings. We used an established Markov model to examine the cost effectiveness of five frequently used categories of THA which differed according to bearing surface and mode of fixation, using data from the National Joint Registry for England and Wales. Kaplan-Meier analyses of rates of revision for men and women were modelled with parametric distributions. Costs of devices were provided by the NHS Supply Chain and associated costs were taken from existing studies. Lifetime costs, lifetime quality-adjusted-life-years (QALYs) and the probability of a device being cost effective at a willingness to pay £20 000/QALY were included in the models. The differences in QALYs between different categories of implant were extremely small (< 0.0039 QALYs for men or women over the patient's lifetime) and differences in cost were also marginal (£2500 to £3000 in the same time period). As a result, the probability of any particular device being the most cost effective was very sensitive to small, plausible changes in quality of life estimates and cost. Our results suggest that available evidence does not support recommending a particular device on cost effectiveness grounds alone. We would recommend that the choice of prosthesis should be determined by the rate of revision, local costs and the preferences of the surgeon and patient. PMID:25820881

  15. Reproductive isolation caused by colour pattern mimicry.

    PubMed

    Jiggins, C D; Naisbit, R E; Coe, R L; Mallet, J

    2001-05-17

    Speciation is facilitated if ecological adaptation directly causes assortative mating, but few natural examples are known. Here we show that a shift in colour pattern mimicry was crucial in the origin of two butterfly species. The sister species Heliconius melpomene and Heliconius cydno recently diverged to mimic different model taxa, and our experiments show that their mimetic coloration is also important in choosing mates. Assortative mating between the sister species means that hybridization is rare in nature, and the few hybrids that are produced are non-mimetic, poorly adapted intermediates. Thus, the mimetic shift has caused both pre-mating and post-mating isolation. In addition, individuals from a population of H. melpomene allopatric to H. cydno court and mate with H. cydno more readily than those from a sympatric population. This suggests that assortative mating has been enhanced in sympatry. PMID:11357131

  16. Identification of Shell Colour Pigments in Marine Snails Clanculus pharaonius and C. margaritarius (Trochoidea; Gastropoda).

    PubMed

    Williams, S T; Ito, S; Wakamatsu, K; Goral, T; Edwards, N P; Wogelius, R A; Henkel, T; de Oliveira, L F C; Maia, L F; Strekopytov, S; Jeffries, T; Speiser, D I; Marsden, J T

    2016-01-01

    Colour and pattern are key traits with important roles in camouflage, warning and attraction. Ideally, in order to begin to understand the evolution and ecology of colour in nature, it is important to identify and, where possible, fully characterise pigments using biochemical methods. The phylum Mollusca includes some of the most beautiful exemplars of biological pigmentation, with the vivid colours of sea shells particularly prized by collectors and scientists alike. Biochemical studies of molluscan shell colour were fairly common in the last century, but few of these studies have been confirmed using modern methods and very few shell pigments have been fully characterised. Here, we use modern chemical and multi-modal spectroscopic techniques to identify two porphyrin pigments and eumelanin in the shell of marine snails Clanculus pharaonius and C margaritarius. The same porphyrins were also identified in coloured foot tissue of both species. We use high performance liquid chromatography (HPLC) to show definitively that these porphyrins are uroporphyrin I and uroporphyrin III. Evidence from confocal microscopy analyses shows that the distribution of porphyrin pigments corresponds to the striking pink-red of C. pharaonius shells, as well as pink-red dots and lines on the early whorls of C. margaritarius and yellow-brown colour of later whorls. Additional HPLC results suggest that eumelanin is likely responsible for black spots. We refer to the two differently coloured porphyrin pigments as trochopuniceus (pink-red) and trochoxouthos (yellow-brown) in order to distinguish between them. Trochopuniceus and trochoxouthos were not found in the shell of a third species of the same superfamily, Calliostoma zizyphinum, despite its superficially similar colouration, suggesting that this species has different shell pigments. These findings have important implications for the study of colour and pattern in molluscs specifically, but in other taxa more generally, since this

  17. Identification of Shell Colour Pigments in Marine Snails Clanculus pharaonius and C. margaritarius (Trochoidea; Gastropoda)

    PubMed Central

    Ito, S.; Wakamatsu, K.; Goral, T.; Edwards, N. P.; Wogelius, R. A.; Henkel, T.; de Oliveira, L. F. C.; Maia, L. F.; Strekopytov, S.; Speiser, D. I.; Marsden, J. T.

    2016-01-01

    Colour and pattern are key traits with important roles in camouflage, warning and attraction. Ideally, in order to begin to understand the evolution and ecology of colour in nature, it is important to identify and, where possible, fully characterise pigments using biochemical methods. The phylum Mollusca includes some of the most beautiful exemplars of biological pigmentation, with the vivid colours of sea shells particularly prized by collectors and scientists alike. Biochemical studies of molluscan shell colour were fairly common in the last century, but few of these studies have been confirmed using modern methods and very few shell pigments have been fully characterised. Here, we use modern chemical and multi-modal spectroscopic techniques to identify two porphyrin pigments and eumelanin in the shell of marine snails Clanculus pharaonius and C margaritarius. The same porphyrins were also identified in coloured foot tissue of both species. We use high performance liquid chromatography (HPLC) to show definitively that these porphyrins are uroporphyrin I and uroporphyrin III. Evidence from confocal microscopy analyses shows that the distribution of porphyrin pigments corresponds to the striking pink-red of C. pharaonius shells, as well as pink-red dots and lines on the early whorls of C. margaritarius and yellow-brown colour of later whorls. Additional HPLC results suggest that eumelanin is likely responsible for black spots. We refer to the two differently coloured porphyrin pigments as trochopuniceus (pink-red) and trochoxouthos (yellow-brown) in order to distinguish between them. Trochopuniceus and trochoxouthos were not found in the shell of a third species of the same superfamily, Calliostoma zizyphinum, despite its superficially similar colouration, suggesting that this species has different shell pigments. These findings have important implications for the study of colour and pattern in molluscs specifically, but in other taxa more generally, since this

  18. Identification of Shell Colour Pigments in Marine Snails Clanculus pharaonius and C. margaritarius (Trochoidea; Gastropoda).

    PubMed

    Williams, S T; Ito, S; Wakamatsu, K; Goral, T; Edwards, N P; Wogelius, R A; Henkel, T; de Oliveira, L F C; Maia, L F; Strekopytov, S; Jeffries, T; Speiser, D I; Marsden, J T

    2016-01-01

    Colour and pattern are key traits with important roles in camouflage, warning and attraction. Ideally, in order to begin to understand the evolution and ecology of colour in nature, it is important to identify and, where possible, fully characterise pigments using biochemical methods. The phylum Mollusca includes some of the most beautiful exemplars of biological pigmentation, with the vivid colours of sea shells particularly prized by collectors and scientists alike. Biochemical studies of molluscan shell colour were fairly common in the last century, but few of these studies have been confirmed using modern methods and very few shell pigments have been fully characterised. Here, we use modern chemical and multi-modal spectroscopic techniques to identify two porphyrin pigments and eumelanin in the shell of marine snails Clanculus pharaonius and C margaritarius. The same porphyrins were also identified in coloured foot tissue of both species. We use high performance liquid chromatography (HPLC) to show definitively that these porphyrins are uroporphyrin I and uroporphyrin III. Evidence from confocal microscopy analyses shows that the distribution of porphyrin pigments corresponds to the striking pink-red of C. pharaonius shells, as well as pink-red dots and lines on the early whorls of C. margaritarius and yellow-brown colour of later whorls. Additional HPLC results suggest that eumelanin is likely responsible for black spots. We refer to the two differently coloured porphyrin pigments as trochopuniceus (pink-red) and trochoxouthos (yellow-brown) in order to distinguish between them. Trochopuniceus and trochoxouthos were not found in the shell of a third species of the same superfamily, Calliostoma zizyphinum, despite its superficially similar colouration, suggesting that this species has different shell pigments. These findings have important implications for the study of colour and pattern in molluscs specifically, but in other taxa more generally, since this

  19. Brilliant Colours from a White Snow Cover

    ERIC Educational Resources Information Center

    Vollmer, Michael; Shaw, Joseph A

    2013-01-01

    Surprisingly colourful views are possible from sparkling white snow. It is well known that similarly colourful features can exist in the sky whenever appropriate ice crystals are around. However, the transition of light reflection and refraction from ice crystals in the air to reflection and refraction from those in snow on the ground is not…

  20. Representing Object Colour in Language Comprehension

    ERIC Educational Resources Information Center

    Connell, Louise

    2007-01-01

    Embodied theories of cognition hold that mentally representing something "red" engages the neural subsystems that respond to environmental perception of that colour. This paper examines whether implicit perceptual information on object colour is represented during sentence comprehension even though doing so does not necessarily facilitate task…

  1. Transcriptomics of colour patterning and coloration shifts in crows.

    PubMed

    Poelstra, J W; Vijay, N; Hoeppner, M P; Wolf, J B W

    2015-09-01

    Animal coloration is one of the most conspicuous phenotypic traits in natural populations and has important implications for adaptation and speciation. Changes in coloration can occur over surprisingly short evolutionary timescales, while recurrence of similar colour patterns across large phylogenetic distances is also common. Even though the genetic basis of pigment production is well understood, little is known about the mechanisms regulating colour patterning. In this study, we shed light on the molecular elements regulating regional pigment production in two genetically near-identical crow taxa with striking differences in a eumelanin-based phenotype: black carrion and grey-coated hooded crows. We produced a high-quality genome annotation and analysed transcriptome data from a 2 × 2 design of active melanogenic feather follicles from head (black in both taxa) and torso (black in carrion and grey in hooded crow). Extensive, parallel expression differences between body regions in both taxa, enriched for melanogenesis genes (e.g. ASIP, CORIN, and ALDH6), indicated the presence of cryptic prepatterning also in all-black carrion crows. Meanwhile, colour-specific expression (grey vs. black) was limited to a small number of melanogenesis genes in close association with the central transcription factor MITF (most notably HPGDS, NDP and RASGRF1). We conclude that colour pattern differences between the taxa likely result from an interaction between divergence in upstream elements of the melanogenesis pathway and genes that provide an underlying prepattern across the body through positional information. A model of evolutionary stable prepatterns that can be exposed and masked through simple regulatory changes may explain the phylogenetically independent recurrence of colour patterns that is observed across corvids and many other vertebrate groups. PMID:26302355

  2. Transcriptomics of colour patterning and coloration shifts in crows.

    PubMed

    Poelstra, J W; Vijay, N; Hoeppner, M P; Wolf, J B W

    2015-09-01

    Animal coloration is one of the most conspicuous phenotypic traits in natural populations and has important implications for adaptation and speciation. Changes in coloration can occur over surprisingly short evolutionary timescales, while recurrence of similar colour patterns across large phylogenetic distances is also common. Even though the genetic basis of pigment production is well understood, little is known about the mechanisms regulating colour patterning. In this study, we shed light on the molecular elements regulating regional pigment production in two genetically near-identical crow taxa with striking differences in a eumelanin-based phenotype: black carrion and grey-coated hooded crows. We produced a high-quality genome annotation and analysed transcriptome data from a 2 × 2 design of active melanogenic feather follicles from head (black in both taxa) and torso (black in carrion and grey in hooded crow). Extensive, parallel expression differences between body regions in both taxa, enriched for melanogenesis genes (e.g. ASIP, CORIN, and ALDH6), indicated the presence of cryptic prepatterning also in all-black carrion crows. Meanwhile, colour-specific expression (grey vs. black) was limited to a small number of melanogenesis genes in close association with the central transcription factor MITF (most notably HPGDS, NDP and RASGRF1). We conclude that colour pattern differences between the taxa likely result from an interaction between divergence in upstream elements of the melanogenesis pathway and genes that provide an underlying prepattern across the body through positional information. A model of evolutionary stable prepatterns that can be exposed and masked through simple regulatory changes may explain the phylogenetically independent recurrence of colour patterns that is observed across corvids and many other vertebrate groups.

  3. Polymorphism of the long-wavelength cone in normal human colour vision

    NASA Astrophysics Data System (ADS)

    Neitz, Jay; Jacobs, Gerald H.

    1986-10-01

    Colour vision is based on the presence of multiple classes of cone each of which contains a different type of photopigment1. Colour matching tests have long revealed that the normal human has three cone types. Results from these tests have also been used to provide estimates of cone spectral sensitivities2. There are significant variations in colour matches made by individuals whose colour vision is classified as normal3-6. Some of this is due to individual differences in preretinal absorption and photopigment density, but some is also believed to arise because there is variation in the spectral positioning of the cone pigments among those who have normal colour vision. We have used a sensitive colour matching test to examine the magnitude and nature of this individual variation and here report evidence for the existence of two different long-wavelength cone mechanisms in normal humans. The different patterns of colour matches made by male and female subjects indicate these two mechanisms are inherited as an X-chromosome linked trait.

  4. Environmental and Genetic Effects on Pigment-Based vs. Structural Component of Yellow Feather Colouration

    PubMed Central

    Matrková, Jana; Remeš, Vladimír

    2012-01-01

    Background Carotenoid plumage is of widespread use in bird communication. Carotenoid-based feather colouration has recently been shown to be dependent on both pigment concentration and feather structure. If these two components are determined differently, one plumage patch may potentially convey different aspects of individual quality. Methodology/Principal Findings We evaluated the effects of genetic and environmental factors on carotenoid-based yellow breast colouration of Great Tit (Parus major) nestlings. By partial cross-fostering, we separated the genetic and pre-natal vs. post-natal parental effects on both the structural and the pigment-based component of carotenoid-based plumage colouration. We also simultaneously manipulated the post-hatching environment by brood size manipulation. The structural component of nestling colouration reflected features of female colouration. On the other hand, the pigment-based component was more affected by rearing conditions presumably representing food quality. While the structural component was related to both origin- and environment-related factors, the pigment-based component seemed to be environment-dependent only. These results support the notion that pigment-based and structural components of feather colouration are determined differently. Conclusions/Significance Chromatic and achromatic components of carotenoid-based feather colouration reflected different aspects of individual quality and history, and thus may potentially form a multicomponent signal. PMID:22590581

  5. Total antioxidant capacity of plant foods, beverages and oils consumed in Italy assessed by three different in vitro assays.

    PubMed

    Pellegrini, Nicoletta; Serafini, Mauro; Colombi, Barbara; Del Rio, Daniele; Salvatore, Sara; Bianchi, Marta; Brighenti, Furio

    2003-09-01

    Epidemiologic studies have demonstrated an inverse association between consumption of fruits and vegetables and morbidity and mortality from degenerative diseases. The antioxidant content of fruits and vegetables may contribute to the protection they offer from disease. Because plant foods contain many different classes and types of antioxidants, knowledge of their total antioxidant capacity (TAC), which is the cumulative capacity of food components to scavenge free radicals, would be useful for epidemiologic purposes. To accomplish this, a variety of foods commonly consumed in Italy, including 34 vegetables, 30 fruits, 34 beverages and 6 vegetable oils, were analyzed using three different assays, i.e., Trolox equivalent antioxidant capacity (TEAC), total radical-trapping antioxidant parameter (TRAP) and ferric reducing-antioxidant power (FRAP). These assays, based on different chemical mechanisms, were selected to take into account the wide variety and range of action of antioxidant compounds present in actual foods. Among vegetables, spinach had the highest antioxidant capacity in the TEAC and FRAP assays followed by peppers, whereas asparagus had the greatest antioxidant capacity in the TRAP assay. Among fruits, the highest antioxidant activities were found in berries (i.e., blackberry, redcurrant and raspberry) regardless of the assay used. Among beverages, coffee had the greatest TAC, regardless of the method of preparation or analysis, followed by citrus juices, which exhibited the highest value among soft beverages. Finally, of the oils, soybean oil had the highest antioxidant capacity, followed by extra virgin olive oil, whereas peanut oil was less effective. Such data, coupled with an appropriate questionnaire to estimate antioxidant intake, will allow the investigation of the relation between dietary antioxidants and oxidative stress-induced diseases.

  6. Sources of Differences in On-Orbit Total Solar Irradiance Measurements and Description of Proposed Laboratory Intercomparison

    NASA Technical Reports Server (NTRS)

    Butler, J.J.; Johnson, B. C.; Rice, J. P.; Shirley, E. L.; Barnes, R.A.

    2008-01-01

    There is a 5 W/sq m (about 0.35 %) difference between current on-orbit Total Solar Irradiance (TSI) measurements. On 18-20 July 2005, a workshop was held at the National Institute of Standards and Technology (NIST) in Gaithersburg, Maryland that focused on understanding possible reasons for this difference, through an examination of the instrument designs, calibration approaches, and appropriate measurement equations. The instruments studied in that workshop included the Active Cavity Radiometer Irradiance Monitor III (ACRIM III) on the Active Cavity Radiometer Irradiance Monitor SATellite (ACRIMSAT), the Total Irradiance Monitor (TIM) on the Solar Radiation and Climate Experiment (SORCE), the Variability of solar IRradiance and Gravity Oscillations (VIRGO) on the Solar and Heliospheric Observatory (SOHO), and the Earth Radiation Budget Experiment (ERBE) on the Earth Radiation Budget Satellite (ERBS). Presentations for each instrument included descriptions of its design, its measurement equation and uncertainty budget, and the methods used to assess on-orbit degradation. The workshop also included a session on satellite- and ground-based instrument comparisons and a session on laboratory-based comparisons and the application of new laboratory comparison techniques. The workshop has led to investigations of the effects of diffraction and of aperture area measurements on the differences between instruments. In addition, a laboratory-based instrument comparison is proposed that uses optical power measurements (with lasers that underEll the apertures of the TSI instruments), irradiance measurements (with lasers that overfill the apertures of the TSI instrument), and a cryogenic electrical substitution radiometer as a standard for comparing the instruments. A summary of the workshop and an overview of the proposed research efforts are presented here.

  7. Blind colour separation of H&E stained histological images by linearly transforming the colour space.

    PubMed

    Celis, R; Romo, D; Romero, E

    2015-12-01

    Blind source separation methods aim to split information into the original sources. In histology, each dye component attempts to specifically characterize different microscopic structures. In the case of the hematoxylin-eosin stain, universally used for routine examination, quantitative analysis may often require the inspection of different morphological signatures related mainly to nuclei patterns, but also to stroma distribution. Stain separation is usually a preprocessing operation that is transversal to different applications. This paper presents a novel colour separation method that finds the hematoxylin and eosin clusters by projecting the whole (r,g,b) space to a folded surface connecting the distributions of a series of [(r-b),g] planes that divide the cloud of H&E tones. The proposed method produces density maps closer to those obtained with the colour mixing matrices set by an expert, when comparing with the density maps obtained using nonnegative matrix factorization (NMF), independent component analysis (ICA) and a state-of-the-art method. The method has outperformed three baseline methods, NMF, Macenko and ICA, in about 8%, 12% and 52% for the eosin component, whereas this was about 4%, 8% and 26% for the hematoxylin component. PMID:26356123

  8. The coevolution theory of autumn colours.

    PubMed Central

    Archetti, Marco; Brown, Sam P.

    2004-01-01

    According to the coevolution theory of autumn colours, the bright colours of leaves in autumn are a warning signal to insects that lay their eggs on the trees in that season. If the colour is linked to the level of defensive commitment of the tree and the insects learn to avoid bright colours, this may lead to a coevolutionary process in which bright trees reduce their parasite load and choosy insects locate the most profitable hosts for the winter. We try to clarify what the theory actually says and to correct some misunderstandings that have been put forward. We also review current research on autumn colours and discuss what needs to be done to test the theory. PMID:15306345

  9. Worldwide patterns of bird colouration on islands.

    PubMed

    Doutrelant, Claire; Paquet, Matthieu; Renoult, Julien P; Grégoire, Arnaud; Crochet, Pierre-André; Covas, Rita

    2016-05-01

    Island environments share distinctive characteristics that offer unique opportunities to investigate parallel evolution. Previous research has produced evidence of an island syndrome for morphological traits, life-history strategies and ecological niches, but little is known about the response to insularity of other important traits such as animal signals. Here, we tested whether birds' plumage colouration is part of the island syndrome. We analysed with spectrophotometry the colouration of 116 species endemic to islands and their 116 closest mainland relatives. We found a pattern of reduced brightness and colour intensity for both sexes on islands. In addition, we found a decrease in the number of colour patches on islands that, in males, was associated with a decrease in the number of same-family sympatric species. These results demonstrate a worldwide pattern of parallel colour changes on islands and suggest that a relaxation of selection on species recognition may be one of the mechanisms involved.

  10. QTL dissection of the loss of green colour during post-anthesis grain maturation in two-rowed barley.

    PubMed

    Emebiri, Livinus C

    2013-07-01

    Ability to genetically manipulate the loss of green colour during grain maturation has potentials for increasing productivity, disease resistance, and drought and heat tolerance in crop plants. Two doubled haploid, two-rowed barley populations (Vlamingh × Buloke and VB9524 × ND11231*12) were monitored over 2 years for loss of green colour during grain filling using a portable active sensor. The aims were to determine the genomic regions that control trait heritability by quantitative trait locus (QTL) analysis, and to examine patterns of QTL-environment interactions under different conditions of water stress. In the Vlamingh × Buloke cross, broad-sense heritability estimate for loss of green colour (measured as the difference in sensor readings taken at anthesis and maturity, ∆SRI) was 0.68, and 0.78 for the VB9524 × ND11231*12 population. In the VB9524 × ND11231*12 population, rapid loss of green colour was positively associated with grain yield and percent plump grains, but in the Vlamingh × Buloke population, a slower loss of green colour (low ∆SRI) was associated with increased grain plumpness. With the aid of a dense array of single nucleotide polymorphisms (SNPs) and EST-derived SSR markers, a total of nine QTLs were detected across the two populations. Of these, a single major locus on the short arm of barley chromosome 5H was consistently linked with trait variation across the populations and multiple environments. The QTL was independent of flowering time and explained between 5.4 and 15.4 % of the variation observed in both populations, depending on the environment, and although a QTL × E interaction was detected, it was largely due to a change in the magnitude of the effect, rather than a change in direction. The results suggest that loss of green colour during grain maturation may be under the control of a simple genetic architecture, but a careful study of target populations and environments would be required for breeding

  11. Comparative characterization of total flavonol glycosides and terpene lactones at different ages, from different cultivation sources and genders of Ginkgo biloba leaves.

    PubMed

    Yao, Xin; Shang, Erxin; Zhou, Guisheng; Tang, Yuping; Guo, Sheng; Su, Shulan; Jin, Chun; Qian, Dawei; Qin, Yong; Duan, Jin-Ao

    2012-01-01

    The extract from Ginkgo biloba leaves has become a very popular plant medicine and herbal supplement for its potential benefit in alleviating symptoms associated with peripheral vascular disease, dementia, asthma and tinnitus. Most research on G. biloba leaves focus on the leaves collected in July and August from four to seven year-old trees, however a large number of leaves from fruit cultivars (trees older than 10 years) are ignored and become obsolete after fruit harvest season (November). In this paper, we expand the tree age range (from one to 300 years) and first comparatively analyze the total flavonol glycosides and terpene lactones at different ages, from different cultivation sources and genders of G. biloba leaves collected in November by using the validated HPLC-ELSD and HPLC-PDA methods. The results show that the contents of total terpene lactones and flavonol glycosides in the leaves of young ginkgo trees are higher than those in old trees, and they are higher in male trees than in female trees. Geographical factors appear to have a significant influence on the contents as well. These results will provide a good basis for the comprehensive utilization of G. biloba leaves, especially the leaves from fruit cultivars.

  12. Levels of total mercury in different fish species and sediments from the Upper Volta Basin at Yeji in Ghana.

    PubMed

    Kwaansa-Ansah, E E; Agorku, S E; Nriagu, J O

    2011-04-01

    In this study, total mercury concentrations were determined in sediments and seven different fish species from the Upper Volta Basin area of Yeji in Ghana. Mercury concentrations found ranged from 44.17 to 85.88 ng/g wet weight for Synodontis gambiesis, from 11.25 to 79.73 ng/g wet weight for Synodontis membranaceus, from 13.11 to 38.64 ng/g wet weight for Synodontis ocellifer, from 16.39 to 25.82 ng/g wet weight for Distishodus rotratus, from 40.80 to 90.30 ng/g wet weight for Bagrus docmac, from 10.48 to 61.90 ng/g wet weight for Chrysichthys nigrodigitatus and from 12.33 to 24.18 ng/g wet weight for Gnathoneus senegalensis. These values are below the 500 ng/g guideline recommended by the WHO/FAO, implying that fish from the Upper Volta Basin area of Yeji are safe for human consumption. Good correlation was observed between mercury concentration and fresh weight (R(2) = 0.6067) and total length (R(2) = 0.8754) for Gnathonemus senegalensis. However, poor correlations were observed between mercury concentration and fresh weight and total length for the other six species. Mercury in sediments ranged from 11.87 to 70.25 ng/g dry weights with a mean of 41.60 ng/g dry weight being below the IAEA threshold of 810 ng/g.. These values show that sections of the Upper Volta River remain relatively clean in spite of substantial loadings of mercury into the river's basin from gold mining activities. PMID:21318735

  13. Levels of total mercury in different fish species and sediments from the Upper Volta Basin at Yeji in Ghana.

    PubMed

    Kwaansa-Ansah, E E; Agorku, S E; Nriagu, J O

    2011-04-01

    In this study, total mercury concentrations were determined in sediments and seven different fish species from the Upper Volta Basin area of Yeji in Ghana. Mercury concentrations found ranged from 44.17 to 85.88 ng/g wet weight for Synodontis gambiesis, from 11.25 to 79.73 ng/g wet weight for Synodontis membranaceus, from 13.11 to 38.64 ng/g wet weight for Synodontis ocellifer, from 16.39 to 25.82 ng/g wet weight for Distishodus rotratus, from 40.80 to 90.30 ng/g wet weight for Bagrus docmac, from 10.48 to 61.90 ng/g wet weight for Chrysichthys nigrodigitatus and from 12.33 to 24.18 ng/g wet weight for Gnathoneus senegalensis. These values are below the 500 ng/g guideline recommended by the WHO/FAO, implying that fish from the Upper Volta Basin area of Yeji are safe for human consumption. Good correlation was observed between mercury concentration and fresh weight (R(2) = 0.6067) and total length (R(2) = 0.8754) for Gnathonemus senegalensis. However, poor correlations were observed between mercury concentration and fresh weight and total length for the other six species. Mercury in sediments ranged from 11.87 to 70.25 ng/g dry weights with a mean of 41.60 ng/g dry weight being below the IAEA threshold of 810 ng/g.. These values show that sections of the Upper Volta River remain relatively clean in spite of substantial loadings of mercury into the river's basin from gold mining activities.

  14. Correlations between art and CFD through colour and shape

    NASA Astrophysics Data System (ADS)

    König, Carola S.

    2011-03-01

    Victorian stained glass artists were among the first to link vibrant colour with strong abstract geometry. This link was further exploited by artists of the early 20th century. Here may be mentioned the works of designers and artists like Mackintosh and of well-known Bauhaus group members like Klee and Kandinsky. Computational fluid dynamics (CFD) and art, particularly abstract art, are undoubtedly intrinsically linked not only by colour, but also by shape as often both contain regular geometries like rectangles and triangles. The use of colour has a multitude of functions in both the pre- and post-processing stages in CFD. These are discussed with an emphasis on the representation of CFD results. Moreover, modelling of fluid dynamics should be seen as but one example of numerical modelling in general. It may be that such common features between these very different metiers are the reason why the numerical modellers amongst us seem to have a natural liking for colourful abstract art. This paper investigates the correlations between art and CFD and is written from the view points of both the professional engineer and the hobby artist.

  15. Ultraviolet sensitivity and colour vision in raptor foraging.

    PubMed

    Lind, Olle; Mitkus, Mindaugas; Olsson, Peter; Kelber, Almut

    2013-05-15

    Raptors have excellent vision, yet it is unclear how they use colour information. It has been suggested that raptors use ultraviolet (UV) reflections from vole urine to find good hunting grounds. In contrast, UV plumage colours in songbirds such as blue tits are assumed to be 'hidden' communication signals, inconspicuous to raptors. This ambiguity results from a lack of knowledge about raptor ocular media transmittance, which sets the limit for UV sensitivity. We measured ocular media transmittance in common buzzards (Buteo buteo), sparrowhawks (Accipiter nisus), red kites (Milvus milvus) and kestrels (Falco tinnunculus) so that, for the first time, raptor UV sensitivity can be fully described. With this information, and new measurements of vole urine reflectance, we show that (i) vole urine is unlikely to provide a reliable visual signal to hunting raptors and (ii) blue tit plumage colours are more contrasting to blue tits than to sparrowhawks because of UV reflectance. However, as the difference between blue tit and sparrowhawk vision is subtle, we suggest that behavioural data are needed to fully resolve this issue. UV cues are of little or no importance to raptors in both vole and songbird interactions and the role of colour vision in raptor foraging remains unclear.

  16. Total ischemic time and outcomes for patients with ST-elevation myocardial infarction: does time of admission make a difference?

    PubMed Central

    Song, Jun-Xian; Zhu, Li; Lee, Chong-You; Ren, Hui; Cao, Cheng-Fu; Chen, Hong

    2016-01-01

    Objective To investigate whether admission time was associated with the delay of reperfusion therapy and in-hospital death in patients with ST-elevation myocardial infarction (STEMI). Methods All patients with STEMI who were admitted to the emergency department and underwent primary percutaneous coronary intervention at Peking University People's Hospital between April 2012 and March 2015 were included. We examined differences in clinical characteristics, total ischemic time, and in-hospital death between patients admitted during off-hours and those admitted during regular hours. Multivariate logistic regression was used to estimate the relationship between off-hours admission and clinical outcome. Results The sample comprised 184 and 105 patients with STEMI admitted to hospital during off-hours and regular hours, respectively. Total ischemic and onset-to-door times were significantly shorter in patients admitted during off-hours than among those admitted during regular hours (all P < 0.05). Door-to-balloon (DTB) time, the rate of DTB time ≤ 90 min, and in-hospital death were comparable between groups. Multivariate logistic regression showed that age and creatinine level, but not off-hours admission, were associated independently with increased in-hospital death. Conclusions Off-hours admission did not result in delayed reperfusion therapy or increased in-hospital mortality in patients with STEMI. Further efforts should focus on identifying pivotal factors associated with the pre-hospital and in-hospital delay of reperfusion therapy, and implementing quality improvement initiatives for reperfusion programs. PMID:27781055

  17. Total phenolic contents and free radical scavenging activities of different extracts of seabuckthorn (Hippophae rhamnoides) pomace without seeds.

    PubMed

    Varshneya, Chandresh; Kant, Vinay; Mehta, Madhuri

    2012-03-01

    In this study, 100% methanolic extract (ME), 70% aqua-methanolic extract (AME) and 100% aqueous extract of seabuckthorn byproduct were used to evaluate antioxidant activity. The total phenolic contents were high in AME (84.28 ± 1.58 mg of Gallic Acid Equivalent (GAE)/gm of extract) compared to other extracts. All the extracts scavenged different in vitro radicals in a concentration-dependent manner. The IC(50) values were lowest in AME for 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt, 2,2-diphenyl-1-picrylhydrazyl, superoxide and nitric oxide radicals, while ME had lowest values for hydroxyl radicals. The reducing power of the extracts increased in a dose-dependent manner and was highest in AME. The findings of this study revealed that seabuckthorn pomace without seed is one of the important resources as an antioxidant for food, pharmaceuticals, cosmetic or nutraceutical industries. PMID:21875373

  18. Determination of total sulfur concentrations in different types of vinegars using high resolution flame molecular absorption spectrometry.

    PubMed

    Ozbek, Nil; Akman, Suleyman

    2016-12-15

    Total sulfur concentrations in vinegars were determined using molecular absorption of carbon monosulfide (CS) determined with a high-resolution continuum source flame atomic absorption spectrometer. The molecular absorption of CS was measured at 258.056nm in an air-acetylene flame. Due to non-spectral interference, as well as the different sensitivities to some sulfur compounds, all sulfur species were oxidized to sulfate using a HNO3 and H2O2 mixture and the analyte addition technique was applied for quantification. The limit of detection (LOD) and limit of quantification (LOQ) were 11.6 and 38.6mgL(-1), respectively. The concentrations of sulfur in various vinegars ranged from ⩽LOD to 163.6mgL(-1). PMID:27451213

  19. Total mercury determination in different tissues of broiler chicken by using cloud point extraction and cold vapor atomic absorption spectrometry.

    PubMed

    Shah, A Q; Kazi, T G; Baig, J A; Afridi, H I; Kandhro, G A; Arain, M B; Kolachi, N F; Wadhwa, S K

    2010-01-01

    A cloud point extraction (CPE) method has been developed for the determination of total mercury (Hg) in different tissues of broiler chicken by cold vapor atomic absorption spectrometry (CVAAS). The broiler chicken tissues (leg, breast, liver and heart) were subjected to microwave assisted digestion in a mixture of nitric acid and hydrogen peroxide (2:1 ratio), prior to preconcentration by CPE. Various parameters such as the amount of ammonium O,O-diethyldithiophosphate (DDTP), concentrations of Triton X-114, equilibrium temperature, time and centrifugation have been studied in order to find the best conditions for the determination of mercury. For validation of proposed method a certified reference material, DORM-2 was used. No significant difference p>0.05 was observed between the experimental results and the certified values of CRM (paired t-test). The limit of detection and quantitation obtained under the optimal conditions were 0.117 and 0.382 microg/kg, respectively. The accumulation of Hg in different tissues were found in the order of, liver>muscles>heart. The concentration of Hg in chicken tissues were found in the range of 1.57-2.75, 1.40-2.27, 1.55-4.22, and 1.39-2.61 microg/kg in leg, breast, liver and heart, respectively.

  20. Colour blindness of the movement-detecting system of the spider Cupiennius salei.

    PubMed

    Orlando, Eva; Schmid, Axel

    2011-02-15

    The nocturnal wandering spider Cupiennius salei has one pair of principal eyes and three pairs of secondary eyes located on the prosoma, which differ in both morphology and function. Their spectral sensitivity, measured with intracellular recordings, is due to three different types of photoreceptors with absorbance maxima in the mid-range of the spectrum, at 480 nm and 520 nm and in the UV at 360 nm. Based on these physiological data colour vision might be possible. In the present study, the ability to discriminate coloured moving stimuli from grey backgrounds was tested. The perception of moving coloured stripes in front of backgrounds with 29 different grey levels was measured by using extracellular recordings from the anterior median eye muscles as a monitoring system. Each of these eyes has two muscles, which increase their activity when moving stimuli are presented in front of a secondary eye. This variation in eye muscle activity can be recorded extracellulary in a living spider using a single channel telemetry device. If colour perception exists, the animal should be able to detect a moving coloured stripe in front of any grey level. Blue, green and red stripes were used as moving stimuli, in front of all 29 grey backgrounds. The results indicate that C. salei is not able to discriminate the coloured stimuli from distinct shades of grey. It is therefore evident that the movement-detecting system in this spider appears to be colour blind.