DICHROMATIC SUM EQUATIONS FOR OUTERPLANAR MAPS

This paper provides a functional equation satisfied by the dichromatic sum function of rooted outer-planar maps. By the equation, the dichromatic sum function can be found explicitly.

Visibility of the bleeding point in acute rectal hemorrhagic ulcer using red dichromatic imaging:A case report

BACKGROUND Red dichromatic imaging(RDI)is a novel image-enhanced endoscopy expected to improve the visibility of the bleeding point.However,it has not been thoroughly investigated.CASE SUMMARY A 91-year-old man developed a sudden massive hematochezia and underwent emergent colonoscopy.An ulcer with pulsatile bleeding was found on the lower rectum.Due to massive bleeding,the exact location of the bleeding point was not easy to detect with white light imaging(WLI).Upon switching to RDI,the bleeding point appeared in deeper yellow compared to the surrounding blood.Thus,RDI enabled us for easier recognition of the bleeding point,and hemostasis was achieved successfully.Furthermore,we reviewed endoscopic images and evaluated the color difference between the bleeding point and surrounding blood for WLI and RDI.In our case,the color difference of RDI was greater than that of WLI(9.75 vs 6.61),and RDI showed a better distinguished bleeding point from the surrounding blood.CONCLUSION RDI may improve visualization of the bleeding point by providing better contrast in color difference relative to surrounding blood.

Sexual dimorphism and sex-differential migration of Little Buntings(Emberiza pusilla)at an East Asian stopover site

Sex differences in morphology provide key information for understanding a species'morphological adaptations in relation to the evolution of sexual selection.In migratory birds,morphological traits have adapted to long-distance travel,and sexual dimorphism is typically related to sex-differential migration phenology.Little Buntings(Emberiza pusilla)have one of the longest migrations and are the least dichromatic species among the Emberiza buntings.In this study,we measured sexual size dimorphism and sexual dichromatism of Little Buntings in relation to the spring arrival dates at a stopover site in Korea.Wing length was the most important predictor for identifying sex;the wings of males were longer than those of females.Males also had a significantly stronger chestnut color of the head feathers than females,but this color difference was more prominent in the spring than in the fall.Males arrived earlier than females by four days.Arrival dates correlated with both size and color,but unlike other bunting species previously studied in the same area,there was no clear sex-differential trend in the relationship between arrival date and morphological characteristics.Seasonal differences in the degree of sexual dichromatism suggest that chestnut plumage coloration can be used as a social or sexual signal of males in the breeding season.The correlation of size and color to early arrival regardless of sex may indicate that a preference for assortative mating exists or that a sex-differential migration strategy is not clearly defined in the early stages of northward migration.Our findings on the sexual dimorphism of Little Buntings provide insight into the evolution of the sex-differential migration of buntings in the East Asian Flyway.

Flight initiation distance, color and camouflage

Camouflage is widespread throughout the animal kingdom allowing individuals to avoid detection and hence save time and energy rather than escape from an approaching predator.Thus,camouflage is likely to have co-evolved with antipredator behavior.Here,we propose that camouflage results in dichotomous escape behavior within and among species with classes of individuals and species with cryptic coloration having shorter flight initiation distances(FIDs;the distance at which an individual takes flight when approached by a human).We report the results of 2 tests of this hypothesis.First,bird species with cryptically colored plumage have consistently shorter FID than closely related species without such color.Within species with sexually dimorphic plumage,brightly colored adult male common pheasants Phasianus colchicus and golden pheasants Chrysolophus pictus have long and variable FID,whereas cryptically colored juveniles and adult females have short and invariable FID.Second,FID in females was predicted by presence or absence of cryptic color,FID in males and their interaction.These findings are consistent with the hypothesis that risk-taking behavior has been attuned to camouflage,and that species with different levels of camouflage differ consistently in their FID.

Bite me： Blue tails as a ＇risky-decoy＇ defense tactic for lizards

Many lizard species use caudal autotomy to escape entrapment. Conspicuous coloration may increase the likelihood of being attacked, but if that attack can be directed towards the autotomous tail this may ultimately increase the chances of the lizard surviving a predatory attack. We tested the hypothesis that brightly-colored tails function to divert predatory attention away from the head and body using pairs of blue-tailed and all-brown clay model lizards. Predatory bird attacks on the 24 blue-tailed models occurred sooner （P = 0.001） than attacks on the 24 all-brown models, and over 7 days blue-tailed models were attacked more often than all-brown models （P = 0.007）. Blue-tailed models were, however, more frequently attacked on the tail than other parts of the body （P 〈 0.001）, while all-brown models were more frequently attacked on the head and body （P = 0.019） which would be more likely to be fatal for a real lizard. Our results suggest that models with a blue tail were more conspicuous than all-brown models, attracting attacks sooner and more often, but that the attacks were predominantly directed at the tail. It is better for individuals to be attacked unsuccessfully many times, than successfully just once. Having a brightly-colored tail may, therefore, act as a ＇risky decoy＇. Despite increased conspicuousness, a blue tail increases the likelihood that the lizard would be able to effect escape through caudal autotomy rather than being grabbed by the head or body [Current Zoology 60 （3）： 333-337, 2014].

Sexual dichromatism,size dimorphism,and microscale anatomy of white wing stripe in blue tits

Achromatic patches are a common element of plumage patterns in many bird species and there is growing body of evidence that in many avian taxa they can play a signaling role in mate choice.Although the blue tit Cyanistes caeruleus is a well-established model species in the studies on coloration,its white wing patch has never been examined in the context of sex-specific trait expression.In this exploratory study,we examined sexual size dimorphism and dichromatism of greater covert’s dots creating white wing patch and analyzed its correlations with current body condition and crown coloration—a trait with established role in sexual selection.Further,we qualitatively analyzed microstructural barb morphology underlying covert’s coloration.We found significant sexual dimorphism in the dot size independent of covert size and sexual dichromatism in both white dot and blue outer covert’s vane spectral characteristics.Internal structure of covert barbs within the white dot was similar to the one found in barbs from the blue part that is,with a medullary area consisting of dead keratinocytes containing channel-typeß-keratin spongy nanostructure and centrally located air cavities.However,it lacked melanosomes which was the main observed difference.Importantly,UV chroma of covert’s blue vane was positively correlated with crown UV chroma and current condition(the latter only in males),which should be a premise for further research on the signal function of the wing stripe.