scholarly journals Ultraviolet vision in larval Neogonodactylus oerstedii

2022 ◽  
Author(s):  
Marisa S. McDonald ◽  
Sitara Palecanda ◽  
Jonathan H. Cohen ◽  
Megan L. Porter
Keyword(s):  
Visual Pigment ◽  
Molecular Diversity ◽  
Animal Kingdom ◽  
Uv Sensitivity ◽  
Color Detection ◽  
Uv Vision ◽  
Ultraviolet Vision ◽  
The Caribbean ◽  
Different Color ◽  
Spectral Channels

Stomatopod crustaceans have among the most complex eyes in the animal kingdom, with up to twelve different color detection channels. The capabilities of these unique eyes include photoreception of ultraviolet (UV) wavelengths (<400 nm). UV vision has been well characterized in adult stomatopods but has not been previously demonstrated in the comparatively simpler larval eye. Larval stomatopod eyes are developmentally distinct from their adult counterpart and have been described as lacking the visual pigment diversity and morphological specializations found in adult eyes. However, recent studies have provided evidence that larval stomatopod eyes are more complex than previously thought and warrant closer investigation. Using electroretinogram recordings in live animals we found physiological evidence of blue and UV sensitive photoreceptors in larvae of the Caribbean stomatopod species Neogonodactylus oerstedii. Transcriptomes of individual larvae were used to identify the expression of three distinct UV opsins transcripts, which may indicate the presence of multiple UV spectral channels. This is the first paper to document UV vision in any larval stomatopod, expanding our understanding of the importance of UV sensitivity in plankton. Similar to adults, larval stomatopod eyes are more complex than expected and contain previously uncharacterized molecular diversity and physiological functions.

scholarly journals The spectral transmission of ocular media suggests ultraviolet sensitivity is widespread among mammals

2014 ◽  
Vol 281 (1780) ◽  
pp. 20132995 ◽  
Author(s):  
R. H. Douglas ◽  
G. Jeffery
Keyword(s):  
Energy Level ◽  
Visual Pigment ◽  
High Spatial Resolution ◽  
Mammalian Species ◽  
Visual Pigments ◽  
Spectral Transmission ◽  
Tree Shrews ◽  
Uv Sensitivity ◽  
Ultraviolet Sensitivity ◽  
Ocular Media

Although ultraviolet (UV) sensitivity is widespread among animals it is considered rare in mammals, being restricted to the few species that have a visual pigment maximally sensitive ( λ max ) below 400 nm. However, even animals without such a pigment will be UV-sensitive if they have ocular media that transmit these wavelengths, as all visual pigments absorb significant amounts of UV if the energy level is sufficient. Although it is known that lenses of diurnal sciurid rodents, tree shrews and primates prevent UV from reaching the retina, the degree of UV transmission by ocular media of most other mammals without a visual pigment with λ max in the UV is unknown. We examined lenses of 38 mammalian species from 25 families in nine orders and observed large diversity in the degree of short-wavelength transmission. All species whose lenses removed short wavelengths had retinae specialized for high spatial resolution and relatively high cone numbers, suggesting that UV removal is primarily linked to increased acuity. Other mammals, however, such as hedgehogs, dogs, cats, ferrets and okapis had lenses transmitting significant amounts of UVA (315–400 nm), suggesting that they will be UV-sensitive even without a specific UV visual pigment.

Fast Color Detection with Two-Terminal P-I-I-N Devices

1996 ◽  
Vol 420 ◽  
Author(s):  
T. Neidlinger ◽  
M. B. Schubert ◽  
G. Schmid ◽  
H. Brummack
Keyword(s):  
Dynamic Range ◽  
Spectral Response ◽  
Hole Transport ◽  
Color Sensor ◽  
Color Separation ◽  
Color Detection ◽  
Color Sensors ◽  
Voltage Transients ◽  
Different Color ◽  
Electric Field Profile

AbstractIn order to overcome the intrinsic speed limitation of amorphous silicon nipin color sensors we present an alternative way of achieving bias-controlled spectral sensitivity of two-terminal thin film devices, piin structures with appropriate band gap and thickness of their single layers can be used as photodetectors that are able to sequentially extract different color signals. Color separation is achieved by controlling the absorption and electric field profile across these piin devices, and thanks to the differences in electron and hole transport properties. Because in contrast to nipin devices there is no need for reverting readout voltages for color separation, this type of sensors can be operated at much higher readout frequencies. Spectral response and bias voltage transients have been analysed up to 20kHz, and preliminiary data are presented on the optimization of speed, dynamic range and color separation by varying bandgap and thickness of p- and i-layers. Furthermore a three-color sensor has been realized by introducing an additional intrinsic layer.

scholarly journals Ultraviolet vision in birds: the importance of transparent eye media

2014 ◽  
Vol 281 (1774) ◽  
pp. 20132209 ◽  
Author(s):  
Olle Lind ◽  
Mindaugas Mitkus ◽  
Peter Olsson ◽  
Almut Kelber
Keyword(s):  
Uv Light ◽  
Bird Species ◽  
Bright Light ◽  
Visual Pigments ◽  
Colour Discrimination ◽  
Animal Kingdom ◽  
Eye Size ◽  
Visual Models ◽  
Ultraviolet Vision ◽  
Ocular Media

Ultraviolet (UV)-sensitive visual pigments are widespread in the animal kingdom but many animals, for example primates, block UV light from reaching their retina by pigmented lenses. Birds have UV-sensitive (UVS) visual pigments with sensitivity maxima around 360–373 nm (UVS) or 402–426 nm (violet-sensitive, VS). We describe how these pigments are matched by the ocular media transmittance in 38 bird species. Birds with UVS pigments have ocular media that transmit more UV light (wavelength of 50% transmittance, λ T0.5 , 323 nm) than birds with VS pigments ( λ T0.5 , 358 nm). Yet, visual models predict that colour discrimination in bright light is mostly dependent on the visual pigment (UVS or VS) and little on the ocular media. We hypothesize that the precise spectral tuning of the ocular media is mostly relevant for detecting weak UV signals, e.g. in dim hollow-nests of passerines and parrots. The correlation between eye size and UV transparency of the ocular media suggests little or no lens pigmentation. Therefore, only small birds gain the full advantage from shifting pigment sensitivity from VS to UVS. On the other hand, some birds with VS pigments have unexpectedly low UV transmission of the ocular media, probably because of UV blocking lens pigmentation.

Human Skin Color Detection Technique Using Different Color Models

2021 ◽  
pp. 261-279
Author(s):  
Ruqaiya Khanam ◽  
Prashant Johri ◽  
Mario José Diván
Keyword(s):  
Human Skin ◽  
Skin Color ◽  
Detection Technique ◽  
Color Models ◽  
Skin Color Detection ◽  
Color Detection ◽  
Different Color

scholarly journals Evolution and spectral tuning of visual pigments in birds and mammals

2009 ◽  
Vol 364 (1531) ◽  
pp. 2941-2955 ◽  
Author(s):  
David M. Hunt ◽  
Livia S. Carvalho ◽  
Jill A. Cowing ◽  
Wayne L. Davies
Keyword(s):  
Visual System ◽  
Visual Pigment ◽  
Spectral Characteristics ◽  
Marine Species ◽  
Visual Pigments ◽  
Common Mechanism ◽  
Light Conditions ◽  
Uv Sensitivity ◽  
Pigment Genes ◽  
Number Of Classes

Variation in the types and spectral characteristics of visual pigments is a common mechanism for the adaptation of the vertebrate visual system to prevailing light conditions. The extent of this diversity in mammals and birds is discussed in detail in this review, alongside an in-depth consideration of the molecular changes involved. In mammals, a nocturnal stage in early evolution is thought to underlie the reduction in the number of classes of cone visual pigment genes from four to only two, with the secondary loss of one of these genes in many monochromatic nocturnal and marine species. The trichromacy seen in many primates arises from either a polymorphism or duplication of one of these genes. In contrast, birds have retained the four ancestral cone visual pigment genes, with a generally conserved expression in either single or double cone classes. The loss of sensitivity to ultraviolet (UV) irradiation is a feature of both mammalian and avian visual evolution, with UV sensitivity retained among mammals by only a subset of rodents and marsupials. Where it is found in birds, it is not ancestral but newly acquired.

scholarly journals Evolution of ultraviolet vision in shorebirds (Charadriiformes)

2009 ◽  
Vol 6 (3) ◽  
pp. 370-374 ◽  
Author(s):  
Anders Ödeen ◽  
Olle Håstad ◽  
Per Alström
Keyword(s):  
Amino Acid ◽  
Visual Pigment ◽  
Colour Vision ◽  
Gene Tree ◽  
Amino Acid Position ◽  
Opsin Gene ◽  
Avian Evolution ◽  
Ultraviolet Vision ◽  
Rynchops Niger ◽  
Sws1 Opsin Gene

Diurnal birds belong to one of two classes of colour vision. These are distinguished by the maximum absorbance wavelengths of the SWS1 visual pigment sensitive to violet (VS) and ultraviolet (UVS). Shifts between the classes have been rare events during avian evolution. Gulls (Laridae) are the only shorebirds (Charadriiformes) previously reported to have the UVS type of opsin, but too few species have been sampled to infer that gulls are unique among shorebirds or that Laridae is monomorphic for this trait. We have sequenced the SWS1 opsin gene in a broader sample of species. We confirm that cysteine in the key amino acid position 90, characteristic of the UVS class, has been conserved throughout gull evolution but also that the terns Anous minutus, A. tenuirostris and Gygis alba , and the skimmer Rynchops niger carry this trait. Terns, excluding Anous and Gygis , share the VS conferring serine in position 90 with other shorebirds but it is translated from a codon more similar to that found in UVS shorebirds. The most parsimonious interpretation of these findings, based on a molecular gene tree, is a single VS to UVS shift and a subsequent reversal in one lineage.

Human Skin Color Detection Using Neural Networks

2015 ◽  
Vol 24 (4) ◽  
pp. 425-436 ◽  
Author(s):  
Mohammadreza Hajiarbabi ◽  
Arvin Agah
Keyword(s):  
Neural Network ◽  
Neural Networks ◽  
Human Skin ◽  
Skin Color ◽  
Skin Detection ◽  
Color Spaces ◽  
Skin Color Detection ◽  
The Neural Network ◽  
Color Detection ◽  
Different Color

AbstractHuman skin detection is an essential phase in face detection and face recognition when using color images. Skin detection is very challenging because of the differences in illumination, differences in photos taken using an assortment of cameras with their own characteristics, range of skin colors due to different ethnicities, and other variations. Numerous methods have been used for human skin color detection, including the Gaussian model, rule-based methods, and artificial neural networks. In this article, we introduce a novel technique of using the neural network to enhance the capabilities of skin detection. Several different entities were used as inputs of a neural network, and the pros and cons of different color spaces are discussed. Also, a vector was used as the input to the neural network that contains information from three different color spaces. The comparison of the proposed technique with existing methods in this domain illustrates the effectiveness and accuracy of the proposed approach. Tests were done on two databases, and the results show that the neural network has better precision and accuracy rate, as well as comparable recall and specificity, compared with other methods.

scholarly journals Color detection algorithm for early fire diagnostics

2021 ◽  
Vol 2131 (2) ◽  
pp. 022123
Author(s):  
E N Ostroukh ◽  
M V Privalov ◽  
S D Markin
Keyword(s):  
Noise Suppression ◽  
Visible Spectrum ◽  
Detection Algorithm ◽  
Video Streams ◽  
Problem Domain ◽  
Detection Approach ◽  
Color Detection ◽  
Different Color ◽  
Selection Of ◽  
Color Components

Abstract In the paper as a problem domain was chosen oil mining and its peculiarities related to early fire diagnostics. Main feature of the described method of early fire diagnostics is application of color detection algorithm together with video sequence acquired from survey cameras. Drawback of the known algorithms of fire diagnostics that also use video streams is selection of the only one color of visible spectrum. Proposed algorithm makes frames preprocessing with purpose of white noise and Gaussian noise suppression. Main feature is complex registration of color components of fire images that are specific to chosen problem domain. Described obtained results of practical application of proposed color detection approach. Experiments were carried out using test video sequences from Bilkent University and Dyntex database. It is shown that advantage of the proposed approach is an ability to select different color components and process them in complex during color detection.

scholarly journals Whole-Genome Sequences of SARS-CoV-2 Isolates from the Dominican Republic

2021 ◽  
Vol 10 (47) ◽  
Author(s):  
R. Paulino-Ramirez ◽  
E. Riego ◽  
A. Vallejo-Degaudenzi ◽  
V. V. Calderon ◽  
L. Tapia ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Gene Flow ◽  
Severe Acute Respiratory Syndrome ◽  
Dominican Republic ◽  
Molecular Diversity ◽  
Whole Genome ◽  
Genome Sequences ◽  
Starting Point ◽  
Genomic Studies ◽  
The Caribbean

Here, we report the genome sequences of five severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) strains that were obtained from symptomatic individuals with travel histories during community surveillance in the Dominican Republic in 2020. These sequences provide a starting point for further genomic studies of gene flow and molecular diversity in the Caribbean nation. Phylogenetic analysis suggests that all genomes correspond to the B.1 variant.

Sign in / Sign up

Export Citation Format

Share Document