The evolution of sexual dichromatism in a large radiation of landfowls: re-examining the female-biased selection in Wallace's model

Sexual dichromatism, the colour difference between males and females, has been particularly important for studying the interplay between sexual and natural selection. However, previous studies on the evolutionary forces of sexual dichromatism examing the Darwin's and Wallace's model have produced mixed results. Phasianidae is a species-rich family with worldwide distribution, occupancy in nearly all terrestrial habitats, and a wide diversity of plumage patterns and colourations. Here, we use phylogenetic comparative methods to test the relationship between sexual dichromatism and colour complexity of males and females on both evolutionary direction and tempo including all species in Phasianidae. We show that the evolutionary direction of sexual dichromatism is negatively correlated with colour complexity in females but not males, and the evolutionary rates of sexual dichromatism are positively correlated with the evolutionary rates of colour complexity in both sexes. These results highlight the important role of female colour evolution in shaping sexual dichromatism in the pheasant family, and provide strong empirical supports for Wallace's hypothesis via a mosaic of sexual and natural selection in both sexes.

Evaluation methodology for light sources used to illuminate highly photosensitive artwork

Spectral energy radiated by light sources is the primary source of colour damage in highly photosensitive artworks (HPAs). However, spectral power distributions differ for different light sources, and the absorption and reflection characteristics of different materials, when irradiated by each narrow spectral energy band, also differ. This could result in large differences in the degree of radiation damage for materials under the same lighting intensity. In this paper, the suitability of different light sources used to illuminate HPAs was experimentally investigated over a long period of time by irradiating nine types of typical HPA materials with 10 different narrow-band light sources. By analysing the colour difference data of the illuminated material against the amount of exposure, a mathematical model relating the spectral composition and the damage to the colour of HPA materials was obtained. Based on this, a colour damage evaluation equation for light sources used for lighting HPAs was proposed. Finally, the equations were discussed using an example.

EFFECTS OF LUMINOUS COLOUR SHIFT Duv ON COLOUR PREFERENCE

Subjective experiment was carried out to investigate the combined effect on the colour preference of the interior style, correlated colour temperature (CCT) and duv. Twenty university age subjects evaluated all 28 conditions with 2 types of the interior style, 2 levels of the CCT and 7 levels of the duv. This paper reports the measured results of the chromaticity shift of the interior surface due to duv and the perception of the colour difference between the condition with any other duv and that with duv0. Subjective evaluation on the colour preference of the entire space related to the interior style, CCT and duv is also summarized. It is concluded that the acceptable range of duv to be classified as the same CCT should be reconsidered, considering colour preference.

Testing Colour Appearance Model Based UCS Using HDR, WCG and COMBVD Datasets

Two colour appearance models based UCSs, CAM16-UCS and ZCAM-QMh, were tested using HDR, WCG and COMBVD datasets. As a comparison, two widely used UCSs, CIELAB and ICTCP, were tested. Metrics of the STRESS and correlation coefficient between predicted colour differences and visual differences, together with local and global uniformity based on their chromatic discrimination ellipses, were applied to test models' performance. The two UCSs give similar performance. The luminance parametric factor kL, and power factor γ, were introduced to optimize colour-difference models. Factors kL and γ of 0.75 and 0.5, gave marked improvement to predict the HDR dataset. Factor kL of 0.3 gave significant improvement in the test of WCG dataset. In the test of COMBVD dataset, optimization provide very limited improvement.

A study on Memory Colours

Memory colour has generated a sustained interest in the colour world. Previous studies mainly focused on the reflection colour chips and colour samples on real scenes or displays. Less attention was paid to the specific attributes of memory colour. In this paper, the forced choice psychophysical experiment method was used to study the preference, the colourfulness and the naturalness memory colours of 29 familiar objects on mobile displays by Chinese observers. The experiment collected the memory colours data and the representative memory colour was specified by CIELAB L*, a*, b* value. The intra-observer and inter-observer variations were analyzed by mean colour difference from the mean values, which was compared with other similar studies. An ellipsoid model was established to represent results in terms of memory colour centre and colour range in CIELAB a* b* space. At the same time, the results of this experiment were compared with those of previous experiments.

Research on double-faced jacquard fabric with compound full-backed structure of three wefts

Weft-backed structures with compound weft colours can express the mixed colour effect. However, this structure is not suitable for jacquard fabrics with a double-faced shading effect in the traditional single layer design mode. Taking twenty-thread sateen with a step number (S) of 7 as an example, this paper investigates a design method for compound full-backed structure with three shaded-weave databases (SWDs) by selecting the primary weaves (PWs), designing the compound full-backed technical points and establishing the compound structure database with three SWDs. With this design method, a double-faced shading effect in combination with non-backed and full-backed effects on different sides of the jacquard fabric at the same position is generated. The fabric colour card was produced with three SWDs and three sets of different coloured wefts, and their colour values were measured, followed by an analysis of the compound structures on the reverse side, lightness, colour purity and colour difference (DE*ab) of the specimens. The results showed that the three covering effects on the reverse side, partly covered, critical position and totally covered, could be adjusted by controlling the step number and the transition direction of PW-C. For the specimens on the edges of the fabric colour card, their lightness and colour purity values showed a uniform transition effect along with the shading process; their colour differences ranged from 1.23 to 3.69, both in the range of 2–5, and showed a trace or slight colour difference between two adjacent fabric specimens, indicating that the colour shading effect with the three SWDs is stable.

Properties of Biocomposites Produced with Thermoplastic Starch and Digestate: Physicochemical and Mechanical Characteristics

This paper presents the results of a study on the influence of the addition of digestate (DG) sludge from an agricultural biogas plant on the mechanical properties of the coating obtained from thermoplastic starch (TPS). The dried, fragmented digestate, some of which had previously undergone ultrasound treatment, is used in the study. Biocomposites are produced by the pouring method using Teflon moulds as matrices. The physicomechanical study included the determination of the basic parameters of the materials obtained. Strength parameters, the contact angle, thermogravimetric properties (TGA), colour and colour difference and moisture absorption are determined. Photographs of the surface of the samples are taken with a scanning electron microscope (SEM) as well. It is found that the addition of the digestate has an advantageous effect on improving the physical and mechanical parameters. In general, samples with digestate also have a higher strength compared to the pure TPS material. The highest tensile strength and Young’s modulus are found in samples with the 14 wt.% addition of ultrasound-treated digestate. On the basis of this study, it can be concluded that the addition of digestate is a promising approach for the production of TPS biocomposites with superior mechanical properties.

The Effects of Munsell Neutral Grey Backgrounds on the Colour of Chrysoprase and the Application of AP Clustering to Chrysoprase Colour Grading

Chrysoprase is a popular gemstone with consumers because of its charming apple green colour but a scientific classification of its colour has not yet been achieved. In this research, we determined the most effective background of the Munsell Chart for chrysoprase colour grading under a 6504 K fluorescent lamp and applied an affinity propagation (AP) clustering algorithm to the colour grading of coloured gems for the first time. Forty gem-quality chrysoprase samples from Australia were studied using a UV-VIS spectrophotometer and Munsell neutral grey backgrounds. The results determined the effects of a Munsell neutral grey background on the observed colour. It was found that the Munsell N9.5 background was the most effective for colour grading in this case. The observed chrysoprase colours were classified into five groups: Fancy Light, Fancy, Fancy Intense, Fancy Deep and Fancy Dark. The feasibility of the colour grading scheme was verified using the colour difference formula DE2000.

Host galaxy line diagnostics for the candidate tidal disruption events XMMSL1 J111527.3+180638 and PTF09axc

We present results of our analysis of spectra of the host galaxies of the candidate Tidal Disruption Events (TDEs) XMMSL1 J111527.3+180638 and PTF09axc to determine the nature of these transients. We subtract the starlight component from the host galaxy spectra to determine the origin of the nuclear emission lines. Using a Baldwin–Phillips–Terlevich (BPT) diagram we conclude that the host galaxy of XMMSL1 J111527.3+180638 is classified as a Seyfert galaxy, suggesting this transient is likely to be caused by (extreme) variability in the active galactic nucleus. We find that the host of PTF09axc falls in the ’star-forming’ region of the BPT-diagram, implying that the transient is a strong TDE candidate. For both galaxies we find a WISE-colour difference of W1 − W2 < 0.8, which means there is no indication of a dusty torus and therefore an active galactic nucleus, seemingly contradicting our BPT finding for the host of XMMSL1 J111527.3+180638. We discuss possible reasons for the discrepant results obtained through the two methods.

Effects of using recycled paper in inkjet printing system on colour difference

Purpose This study aims to examine the colour changes affecting inkjet prints after the recycling of papers. Design/methodology/approach For recycling, papers prepared with the INGEDE 11p standard are recycled four times. Pulping, storage, flotation, beating and bleaching processes are applied for each recycling, respectively. Inkjet prints are made on the obtained test papers, and colour measurements are made using an X-Rite eXact spectrophotometer according to the ISO 13655:2017 standard. These processes are applied again to the papers which are recycled four times, and the results are analyzed. In addition, the values of ΔE00 ′, ΔL′, ΔH ′ and ΔC′ are calculated according to ISO 11664-6:2014 standard by making some calculations according to obtained the L′a′b′ values. Findings It is determined that the ΔE00 value increases after each recycling in cyan magenta and yellow colour, whereas it decreases in black. The highest ΔE00 value is calculated after the fourth recycling stage is yellow with a value of 8.33. The lowest ΔE00 value detected is black with a value of 0.76 after the fourth recycling stage. This paper observes that the colour with the most variation in hue angle among recycling repetitions is black and the colour with the highest hue angle value is yellow. It is seen that repeating recycling causes increase in the chromatic values of the prints. Originality/value After the fourth recycling stage, colour changes have reached an important point and can cause important printing problems. In this case, the customer’s approval must be obtained to continue printing. This case is valid for ΔE00 values. Colour differences for print contrast, trapping and print chroma values are either not very important or are positive for quality.