Search results for "Color"
showing 10 items of 2721 documents
Trichromatic color vision in the salamander (Salamandra salamandra)
1995
Spectral sensitivity functions were measured between 334 nm and 683 nm in Salamandra salamandra by utilizing two behavioral reactions: the negative phototactic response, and the prey catching behavior elicited by a moving worm dummy. The action spectrum of the negative phototactic response revealed 3 pronounced maxima: at 360–400 nm, at 520–540 nm, and at 600–640 nm. In the range around 450 nm, there was a “reaction gap” where sensitivity could not be measured. The action spectrum of the prey catching behavior was entirely different: maximal sensitivity was found at 500 nm and at 570 nm. Between 500 nm and 334 nm sensitivity decreased continuously for about 1 log unit (Fig. 6).
THERMOREGULATION CONSTRAINS EFFECTIVE WARNING SIGNAL EXPRESSION
2009
Evolution of conspicuous signals may be constrained if animal coloration has nonsignaling as well as signaling functions. In aposematic wood tiger moth (Parasemia plantaginis) larvae, the size of a warning signal (orange patch on black body) varies phenotypically and genetically. Although a large warning signal is favored as an antipredator defense, we hypothesized that thermoregulation may constrain the signal size in colder habitats. To test this hypothesis, we conducted a factorial rearing experiment with two selection lines for larval coloration (small and large signal) and with two temperature manipulations (high and low temperature environment). Temperature constrained the size and br…
Significance of the dorsal zigzag pattern of Vipera latastei gaditana against avian predators
2005
Summary 1. Aposematism is an antipredatory strategy in which prey animals conspicuously signal their noxiousness to potential predators. This successful strategy is based on avoidance learning of predators. 2. Most species in the viperid genus Vipera have a characteristic dorsal zigzag pattern. It has previously been suggested that the dorsal zigzag pattern of Vipera berus (the adder) has a cryptic function and thus makes the snake less conspicuous to avian predators. However, a recent experiment suggested that the pattern may function as an aposematic signal rather than being cryptic, and therefore induces active avoidance in avian predators. 3. We conducted a field experiment in Donana na…
METABOLIC PROMOTERS AFFECT YIELD AND FRUIT QUALITY OF 'SANFILIPPARA' AND 'TRABIA' LOQUAT
2015
Preliminary field trials with foliar applications of phenylalanine, methionine, oxylipins and sugars have shown improvements of external color, sugar content and uniformity of maturation in grapes, pome fruits, tomatoes and melons. In this study, we hypothesized that similar improvements could be obtained both in fruit of âTrabiaâ and âSanfilipparaâ loquat (Eriobotrya japonica Lindl.) with applications of a commercial formulate called Sunred (Biolchim, Bologna, Italy) and containing various concentrations of the above metabolic promoters. The study was conducted on 12 âSanfilipparaâ and 12 âTrabiaâ adult loquat trees grown in an orchard near Palermo, Italy. Half of the trees…
Prognostic value of neurotrophic growth factor (BDNF) in patients with colorectal cancer during chemotherapy
2019
INTRODUCTION: The brain-derived neurotrophic factor (BDNF) is a protein belonging to neurotrophins that plays a key role in the proper development and functioning of the mammalian central nervous system. Previous studies have focused on assessment of the BDNF concentration in blood serum as a potential biomarker in neurological disorders. Recently, the BDNF signalling pathway has been recognised as a potential target for anticancer drugs, while its receptor (TrkB) as an oncogene in colorectal cancer cells. Despite the significant role in carcinogenesis, there are few studies on BDNF as a biomarker in colorectal cancer. MATERIAL AND METHODS: The study included 25 patients with clinically and…
Evidence of Seasonal Variation in Body Color in Adults of the Parasitoid Cirrospilus pictus (Hymenoptera: Eulophidae) in Sicily, Italy
2023
As part of the studies on the morphological color variation of insects, a case study on the seasonal body color variation of Cirrospilus pictus (Nees) (Hymenoptera: Eulophidae: Eulophinae) parasitoid of leafminers is reported. Observations were made from January 2000 to December 2003 in north-western Sicily (Italy), in relation to sex, body regions of adults and seasonal periods. Wasps parasitizing Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) were collected from organic citrus orchards (Citrus limon L., var. “Femminello zagara bianca” and “Femminello comune”). Adults were grouped in classes: yellow males, black males, yellow females, yellow–black females and black females. …
Simultaneous Color Contrast in Goldfish— a Quantitative Study
1997
AbstractA set of 9–15 colored test fields was presented to goldfish. In Experiment 1, test field hues ranged from green through yellow to red; in Experiment 2, the hues varied from blue through gray to yellow. In the training conditions, the test fields were presented with a gray or black surround. The fish learned to choose one intermediate test field hue by rewarding them with food. In the test conditions, the color of the surround was changed from gray to green, or red (Experiment 1), and from black to blue, or yellow (Experiment 2). The choice behavior of the goldfish changed substantially: one of the test fields other than the training test field was preferred. Direction and strength o…
Colour assessment of milk and milk products using computer vision system and colorimeter
2021
Abstract A computer vision system (CVS) and a colorimeter were compared for their abilities to measure the colour of twenty-seven different milks and milk products. The frequency of similarity test showed that CVS-generated colour chips were similar to the actual sample colour in all trials (100%). The CVS-obtained colours were found to be more similar to the colour of sample visualised on the monitor, compared with colorimeter-generated colour chips, with values of 83.3–100.0% depending on the milk product. The third test showed that there was difference between colour measured by CVS and the colorimeter; colorimeter readings resulted in a darker and yellower colour based on average L∗a∗b∗…
Digital selection of composite resin shade using cross polarized photography and a standardized white balance gray reference card
2021
Purpose The aim of the present case report was to describe, through a clinical case, a step-by-step technique, for the digital selection of composite resin shades using cross polarization and white balance employing a standardized reference card. Case Description After intraoral impression, a digital diagnostic wax up was developed. A 3D printed cast was used to fabricate a lingual polyvinyl siloxane matrix. First a cross-polarized image of the contralateral central incisor was taken in RAW format, using a gray reference card. The digital image was manipulated using this card as a reference, to obtain reliable color values. The obtained color values, from the contralateral central incisor, …
Directive local color transfer based on dynamic look-up table
2019
Abstract Color transfer in image processing usually suffers from misleading color mapping and loss of details. This paper presents a novel directive local color transfer method based on dynamic look-up table (D-DLT) to solve these problems in two steps. First, a directive mapping between the source and the reference image is established based on the salient detection and the color clusters to obtain directive color transfer intention. Then, dynamic look-up tables are created according to the color clusters to preserve the details, which can suppress pseudo contours and avoid detail loss. Subjective and objective assessments are presented to verify the feasibility and the availability of the…