scholarly journals Lens and cornea limit UV vision of birds – a phylogenetic perspective

2021 ◽  
Author(s):  
Peter Olsson ◽  
Olle Lind ◽  
Mindaugas Mitkus ◽  
Kaspar Delhey ◽  
Almut Kelber
Keyword(s):  
Uv Light ◽  
Strong Predictor ◽  
Chromatic Aberration ◽  
Limiting Factor ◽  
Ancestral State ◽  
Eye Size ◽  
Phylogenetic Perspective ◽  
Uv Vision ◽  
Ocular Media ◽  
Specific Contribution

Most vertebrates have UV-sensitive vision, but the UV-sensitivity of their eyes is limited by the transmittance of the ocular media, and the specific contribution of the different media (cornea, lens) has remained unclear. Here we describe the transmittance of all ocular media (OMT), as well as that of lenses and corneas of birds. For 66 species belonging to 18 orders, the wavelength at which 50% of light is transmitted through the ocular media to the retina (λT0.5) ranges from 310 to 398 nm. Low λT0.5 corresponds to more UV-light transmitted. Corneal λT0.5 varies only between 300 and 345 nm, whereas lens λT0.5 values are more variable (between 315 and 400 nm) and tend to be the limiting factor, determining OMT in the majority of species. OMT λT0.5 is positively correlated with eye size, but λT0.5 of corneas and lenses are not correlated with their thickness when controlled for phylogeny. Corneal and lens transmittances do not differ between birds with UV- and violet-sensitive SWS1 opsin when controlling for eye size and phylogeny. Phylogenetic relatedness is a strong predictor of OMT, and ancestral state reconstructions suggest that from ancestral intermediate OMT, highly UV-transparent ocular media (low λT0.5) evolved at least five times in our sample of birds. Some birds have evolved in the opposite direction towards a more UV-opaque lens, possibly due to pigmentation, likely to mitigate UV-damage or reduce chromatic aberration.

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.

scholarly journals Lens transmittance shapes ultraviolet sensitivity in the eyes of frogs from diverse ecological and phylogenetic backgrounds

2020 ◽  
Vol 287 (1918) ◽  
pp. 20192253 ◽  
Author(s):  
Carola A. M. Yovanovich ◽  
Michele E. R. Pierotti ◽  
Almut Kelber ◽  
Gabriel Jorgewich-Cohen ◽  
Roberto Ibáñez ◽  
...  
Keyword(s):  
Uv Light ◽  
Visible Spectrum ◽  
Diel Activity ◽  
Closely Related Species ◽  
Eye Size ◽  
Diel Activity Pattern ◽  
Ocular Media ◽  
Uv Transmittance ◽  
The Relationship ◽  
Lens Transmittance

The amount of short wavelength (ultraviolet (UV), violet and blue) light that reaches the retina depends on the transmittance properties of the ocular media, especially the lens, and varies greatly across species in all vertebrate groups studied previously. We measured the lens transmittance in 32 anuran amphibians with different habits, geographical distributions and phylogenetic positions and used them together with eye size and pupil shape to evaluate the relationship with diel activity pattern, elevation and latitude. We found an unusually high lens UV transmittance in the most basal species, and a cut-off range that extends into the visible spectrum for the rest of the sample, with lenses even absorbing violet light in some diurnal species. However, other diurnal frogs had lenses that transmit UV light like the nocturnal species. This unclear pattern in the segregation of ocular media transmittance and diel activity is shared with other vertebrates and is consistent with the absence of significant correlations in our statistical analyses. Although we did not detect a significant phylogenetic effect, closely related species tend to have similar transmittances, irrespective of whether they share the same diel pattern or not, suggesting that anuran ocular media transmittance properties might be related to phylogeny.

scholarly journals Lens Transmittance Shapes UV Sensitivity in the Eyes of Frogs from Diverse Ecological and Phylogenetic Backgrounds

2019 ◽  
Author(s):  
Carola A. M. Yovanovich ◽  
Michele E. R. Pierotti ◽  
Almut Kelber ◽  
Gabriel Jorgewich-Cohen ◽  
Roberto Ibáñez ◽  
...  
Keyword(s):  
Uv Light ◽  
Visible Spectrum ◽  
Diel Activity ◽  
Closely Related Species ◽  
Eye Size ◽  
Diel Activity Pattern ◽  
Ocular Media ◽  
Uv Transmittance ◽  
The Relationship ◽  
Lens Transmittance

ABSTRACTThe amount of short wavelength (UV, violet and blue) light that reaches the retina depends on the transmittance properties of the ocular media, especially the lens, and varies greatly across species in all vertebrate groups studied previously. We measured the lens transmittance in 32 anuran amphibians with different habits, geographic distributions, and phylogenetic positions and used them together with eye size and pupil shape to evaluate the relationship with diel activity pattern, elevation and latitude. We found an unusually high lens UV transmittance in the most basal species, and a range that extends into the visible spectrum for the rest of the sample, with lenses even absorbing violet light in some diurnal species. However, other diurnal frogs had lenses that transmit UV light like the nocturnal species. This unclear pattern in the segregation of ocular media transmittance and diel activity is shared with other vertebrates and is consistent with the absence of significant correlations in our statistical analyses. Although we did not detect a significant phylogenetic effect, closely related species tend to have similar transmittances, irrespective of whether they share the same diel pattern or not, suggesting that ocular media transmittance properties might be related to phylogeny.

Toward High-Resolution Low-Voltage SEM

1988 ◽  
Vol 46 ◽  
pp. 218-219
Author(s):  
Zhifeng Shao
Keyword(s):  
Low Voltage ◽  
Spherical Aberration ◽  
Chromatic Aberration ◽  
Limiting Factor ◽  
Operating Voltage ◽  
Probe Radius ◽  
Non Local ◽  
Electron Microscopes ◽  
Image Position ◽  
Scanning Electron Microscopes

Recently, low voltage (≤5kV) scanning electron microscopes have become popular because of their unprecedented advantages, such as minimized charging effects and smaller specimen damage, etc. Perhaps the most important advantage of LVSEM is that they may be able to provide ultrahigh resolution since the interaction volume decreases when electron energy is reduced. It is obvious that no matter how low the operating voltage is, the resolution is always poorer than the probe radius. To achieve 10Å resolution at 5kV (including non-local effects), we would require a probe radius of 5∽6 Å. At low voltages, we can no longer ignore the effects of chromatic aberration because of the increased ratio δV/V. The 3rd order spherical aberration is another major limiting factor. The optimized aperture should be calculated as

scholarly journals Towards a Natural Classification of Hyphodontia Sensu Lato and the Trait Evolution of Basidiocarps within Hymenochaetales (Basidiomycota)

2021 ◽  
Vol 7 (6) ◽  
pp. 478
Author(s):  
Xue-Wei Wang ◽  
Tom W. May ◽  
Shi-Liang Liu ◽  
Li-Wei Zhou
Keyword(s):  
Phylogenetic Analyses ◽  
Taxonomic Status ◽  
Ancestral State ◽  
Trait Evolution ◽  
Natural Classification ◽  
Multiple Loci ◽  
The Family ◽  
Phylogenetic Perspective ◽  
Taxonomic Framework ◽  
First Time

Hyphodontia sensu lato, belonging to Hymenochaetales, accommodates corticioid wood-inhabiting basidiomycetous fungi with resupinate basidiocarps and diverse hymenophoral characters. Species diversity of Hyphodontia sensu lato has been extensively explored worldwide, but in previous studies the six accepted genera in Hyphodontia sensu lato, viz. Fasciodontia, Hastodontia, Hyphodontia, Kneiffiella, Lyomyces and Xylodon were not all strongly supported from a phylogenetic perspective. Moreover, the relationships among these six genera in Hyphodontia sensu lato and other lineages within Hymenochaetales are not clear. In this study, we performed comprehensive phylogenetic analyses on the basis of multiple loci. For the first time, the independence of each of the six genera receives strong phylogenetic support. The six genera are separated in four clades within Hymenochaetales: Fasciodontia, Lyomyces and Xylodon are accepted as members of a previously known family Schizoporaceae, Kneiffiella and Hyphodontia are, respectively, placed in two monotypic families, viz. a previous name Chaetoporellaceae and a newly introduced name Hyphodontiaceae, and Hastodontia is considered to be a genus with an uncertain taxonomic position at the family rank within Hymenochaetales. The three families emerged between 61.51 and 195.87 million years ago. Compared to other families in the Hymenochaetales, these ages are more or less similar to those of Coltriciaceae, Hymenochaetaceae and Oxyporaceae, but much older than those of the two families Neoantrodiellaceae and Nigrofomitaceae. In regard to species, two, one, three and 10 species are newly described from Hyphodontia, Kneiffiella, Lyomyces and Xylodon, respectively. The taxonomic status of additional 30 species names from these four genera is briefly discussed; an epitype is designated for X. australis. The resupinate habit and poroid hymenophoral configuration were evaluated as the ancestral state of basidiocarps within Hymenochaetales. The resupinate habit mainly remains, while the hymenophoral configuration mainly evolves to the grandinioid-odontioid state and also back to the poroid state at the family level. Generally, a taxonomic framework for Hymenochaetales with an emphasis on members belonging to Hyphodontia sensu lato is constructed, and trait evolution of basidiocarps within Hymenochaetales is revealed accordingly.

The Detection of Near-Ultraviolet Light by Nonmigratory and Migratory Birds

The Auk ◽  
1984 ◽  
Vol 101 (1) ◽  
pp. 53-58 ◽  
Author(s):  
John W. Parrish ◽  
James A. Ptacek ◽  
Kevin L. Will
Keyword(s):  
Migratory Birds ◽  
Uv Light ◽  
Mate Recognition ◽  
Insectivorous Birds ◽  
Uv Spectrum ◽  
Near Ultraviolet ◽  
Ultraviolet Reflectance ◽  
Uv Reflectance ◽  
Uv Vision ◽  
First Time

Abstract Near-ultraviolet (UV) light reception was demonstrated for the first time in three species of nonmigratory emberizid and passerid birds. Behavioral data also established that eight additional alcedinid and emberizid birds can detect near-UV wavelengths. The finding that these more recently evolved species can see near-UV light implies that near-UV vision is probably an important visual capability in most, if not all, diurnal birds. Although the utility of near-UV reception for birds remains equivocal, the fact that nonmigratory as well as migratory birds can perceive UV suggests that birds may be able to utilize the UV spectrum for homing, orientation, and navigation, as do the UV-sensitive arthropods. It also can be inferred that UV vision may be especially useful to insectivorous birds for the detection of UV reflectance patterns, which many otherwise cryptic arthropods possess for mate recognition. Ultraviolet reflectance patterns also may be useful to frugivorous and nectarivorous birds for the detection of food items.

scholarly journals Owls lack UV-sensitive cone opsin and red oil droplets, but see UV light at night: Retinal transcriptomes and ocular media transmittance

2019 ◽  
Vol 158 ◽  
pp. 109-119 ◽  
Author(s):  
Julia Höglund ◽  
Mindaugas Mitkus ◽  
Peter Olsson ◽  
Olle Lind ◽  
Anna Drews ◽  
...  
Keyword(s):  
Uv Light ◽  
Light At Night ◽  
Oil Droplets ◽  
Cone Opsin ◽  
Ocular Media

Evaluating the Spatial Consequence of Interest Rate Ceiling Using a Spatial Regime Change Approach

2017 ◽  
Vol 63 (2) ◽  
pp. 166-186 ◽  
Author(s):  
Onyumbe E. Lukongo ◽  
Thomas Miller
Keyword(s):  
Interest Rate ◽  
Strong Evidence ◽  
Financial Services ◽  
Spatial Clustering ◽  
Strong Predictor ◽  
Trade Association ◽  
Acquisition Costs ◽  
Specific Contribution ◽  
Empirical Framework ◽  
Jel Classifications

The article provides the empirical framework and steps toward the evaluation of the spatial consequence of the 17% interest rate ceiling in Arkansas using a new database from the trade association for installment lenders, the American Financial Services Association. The specific contribution of this study is to build and apply the installment loan accessibility index within the context of the spatial regime models. Results suggest strong evidence of spatial clustering of counties with similar (low or high) installment loan usage rates across the study area and two spatial regimes at work. The loan accessibility index is a strong predictor of the installment loan usage in the study area. That is, an increase in the loan acquisition costs due to the 17% interest rate cap puts interior counties’ residents at disadvantage compared with residents of border counties who can cross the borders to get small dollar loans. JEL Classifications: C51, C52, G23, G28

Concentration of β-ecydisone (20E) in susceptible and resistant accessions of Pfaffia glomerata infected with Meloidogyne incognita and histological characterisation of resistance

Nematology ◽  
2010 ◽  
Vol 12 (5) ◽  
pp. 701-709 ◽  
Author(s):  
Ana Cristina M.M. Gomes ◽  
Michel Nicole ◽  
Jean Kleber Mattos ◽  
Sarazete Izidia Vaz Pereira ◽  
Paulo Pereira ◽  
...  
Keyword(s):  
Meloidogyne Incognita ◽  
Uv Light ◽  
Pearson Correlation ◽  
Resistance Mechanism ◽  
Giant Cells ◽  
Resistance Mechanisms ◽  
Root Production ◽  
Limiting Factor ◽  
Root Knot Nematode ◽  
Pfaffia Glomerata

Abstract Pfaffia glomerata is a medicinal plant widely distributed in Brazil, which is considered the world's greatest supplier of P. glomerata roots. Among active ingredients contained in this plant, the steroid β-ecydisone (20E) is the most important compound extracted from roots. This steroid presents therapeutic properties for the treatment of diabetes and haemorrhoids, besides having bioenergy, tonic and aphrodisiac effects. The root-knot nematode Meloidogyne spp. is a major limiting factor in root production. Recent studies showed resistance of accessions of P. glomerata to Meloidogyne incognita. The aims of this work were: i) to correlate the concentration of 20E with resistance and susceptibility of P. glomerata accessions to M. incognita in inoculated and non-inoculated plants; ii) to study the effect of the parasitism of M. incognita on the concentration of the steroid 20E in the roots; and iii) to clarify resistance mechanisms by comparing the response of a highly resistant UFV with a highly susceptible accession (Farm) to nematode infection. The concentration of 20E in the healthy susceptible Farm accession was significantly higher than in the healthy resistant UFV accession, showing that the resistance mechanism was not related to 20E concentrations. Plants of the Farm accession infected with M. incognita showed higher levels of 20E than the non-infected control. A positive and significant Pearson correlation coefficient was observed between 20E concentrations and gall indexes. Resistance of UFV to the root-knot nematode M. incognita was associated with unidentified factors that limited nematode penetration or emigration of second-stage juveniles and with post-penetration responses, including the hypersensitive response. Giant cells were sometimes found in the resistant cultivar, but displayed a highly vacuolated and degraded cytoplasm with thinner cell walls than those induced in the susceptible accession. Microscope observations under UV light showed a strong autofluorescence, suggesting that phenolic compounds may be involved in ginseng UFV resistance.

scholarly journals A New Method for Conservation of Ancient Colored Drawing on Hemp Textiles

2020 ◽  
Author(s):  
Jiaojiao Liu ◽  
Yuhu Li ◽  
Huiping Xing ◽  
Daodao Hu ◽  
Xiaolian Chao ◽  
...  
Keyword(s):  
Uv Light ◽  
Chromatic Aberration ◽  
Element Distribution ◽  
Depth Of Field ◽  
Conservation Treatment ◽  
Before And After ◽  
Wet Heat ◽  
Historical Culture ◽  
Restoration And Protection ◽  
Cultural Relics

Abstract As a kind of textile, hemp artifact is a valuable cultural heritage. Suffering from several degradation factors in the preservation of cultural relics, some ancient hemp colored-paintings have been damaged, further affected their ornamental values. Therefore, it is urged to take the suitable conservation measures to protect the precious hemp artifacts for the historical culture succession. In this paper, an examination and analysis of the hemp colored paintings were the first step to propose an appropriate conservation treatment. Ultra-depth-of-field microscope was used to identify the kinds of fiber, and scanning electron microscope (SEM) was utilized to observe their condition and surface morphology. The element distribution and composition were identified by SEM, energy disperse spectroscopy (EDS) and X-ray fluorescence spectroscopy (XRF). Gas chromatography-mass spectrometer (GC-MS) was applied to identify the kinds of binding media and amino acid composition. Moreover, novel reinforcement materials and technology were proposed with the principle of compatibility and feasibility. The properties of tensile strength, aging resistance and chromatic aberration were tested before and after dry heat aging, wet heat aging and UV light aging. After systematic examination and evaluation of the hemp colored paintings and reinforcement materials, the optimal conservation treatment was finally established, and the Chinese hemp painting as an example has been protected successfully. This paper provides new methods and ideas for the restoration and protection of the linen cultural relics, which would promote the progress of protecting valuable cultural heritages.

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