scholarly journals Far-UV reflectance and stress of narrowband AlF₃/LaF₃ multilayers

2021 ◽  
Author(s):  
Paloma Lopez Reyes ◽  
Carlos Honrado-Benítez ◽  
Nuria Gutiérrez-Luna ◽  
Álvaro Ríos-Fernández ◽  
Luis Rodríguez-de Marcos ◽  
...  
Keyword(s):  
Uv Reflectance

scholarly journals The role of ultraviolet reflectance and pattern in the pollination system of Hypoxis camerooniana (Hypoxidaceae)

AoB Plants ◽  
2019 ◽  
Vol 11 (5) ◽  
Author(s):  
Yannick Klomberg ◽  
Raissa Dywou Kouede ◽  
Michael Bartoš ◽  
Jan E J Mertens ◽  
Robert Tropek ◽  
...  
Keyword(s):  
Plant Species ◽  
Central Africa ◽  
Complete Removal ◽  
Reproductive Organs ◽  
Specific Pattern ◽  
Flowering Plant ◽  
Pollination System ◽  
Mount Cameroon ◽  
Uv Reflectance ◽  
Montane Grasslands

Abstract Apart from floral morphology and colours perceived by the human eye, ultraviolet (UV) reflectance acts as an important visual advertisement of numerous flowering plant species for pollinators. However, the effect of UV signalling on attracting pollinators of particular plant species is still insufficiently studied, especially in the Afrotropics. Therefore, we studied the pollination system of Hypoxis camerooniana in montane grasslands of Mount Cameroon, West/Central Africa. We focused mainly on the effects of the flowers’ UV reflectance on its visitors. We experimentally removed UV reflection from petals either completely or partially. Thereafter, flower visitors were recorded and pistils were collected post-flowering to quantify germinated pollen tubes per treatments. The most important visitors were bees, followed by flies. Due to their contacts with reproductive organs bees are considered as the primary pollinators. Visitation rates were lower when UV reflectance was completely removed, whereas the decrease of frequency on half-treated flowers did not differ significantly from control treatments. The complete removal of UV also affected bees’ landing behaviour, but not that of flies. We showed that the presence of UV reflectance is more important than UV pattern for bees visiting flowers of H. camerooniana. We hypothesize that exploiting all flowers irrespective of their pattern can be more efficient for pollinators in the open grasslands of high altitudes to spot these relatively scarce flowers by their UV reflectance. Furthermore, we highlight the necessity of both experimental and natural controls in similar studies to control for additional effects of the used UV manipulations. Many plants advertise their flowers with UV reflectance visible to their insect visitors. By manipulating the UV reflectance and pattern of Hypoxis camerooniana in the Afromontane grasslands of Mount Cameroon, we have shown how crucial it is for the predominant visitor, bees. Both bees' preferences for flowers and their behaviour during visits are influenced by changes in UV reflectance. However, the presence of some UV signal is more important than the specific pattern. Especially in montane grasslands with higher UV irradiation, the UV floral colours are important for recognition of flowers by potential pollinators.

Ultraviolet reflectance and female mating preferences in the common kestrel (Falco tinnunculus)

2008 ◽  
Vol 86 (6) ◽  
pp. 479-483 ◽  
Author(s):  
E. Zampiga ◽  
G. Gaibani ◽  
D. Csermely
Keyword(s):  
Female Mate Choice ◽  
Female Preference ◽  
Visible Spectral Range ◽  
Falco Tinnunculus ◽  
Uv Filter ◽  
Skin Reflectance ◽  
Ultraviolet Reflectance ◽  
Uv Reflectance ◽  
Female Mating Preferences ◽  
Uv Reflection

Previous studies revealed the importance of plumage brightness (considering only the visible spectral range) in female mate choice of common kestrels ( Falco tinnunculus L., 1758). Our study focuses on the effect of UV reflectance on female preference; we hypothesize that common kestrel females prefer males with UV-reflecting plumage and refuse, or are not attracted to, males whose plumage UV reflectance is prevented. We tested the preference of 20 captive females who were given a choice between two males, one behind a UV-transmitting (UV+) filter and another one behind a UV-blocking (UV–) filter. Female preference was measured as frequency and duration of visits to either male, specifically by sitting on the perch or hanging on to the partition wall. Females visited the male behind the UV+ filter more often than the male behind the UV– filter, indicating that females prefer males with UV-reflecting plumage than males without UV reflection. UV plumage and skin reflectance could provide females with information regarding current male conditions more so than other colours and other morphological parameters.

scholarly journals UV reflectance as a cue in egg discrimination in twoPriniaspecies exploited differently by brood parasites in Taiwan

Ibis ◽  
2013 ◽  
Vol 155 (3) ◽  
pp. 571-575 ◽  
Author(s):  
Canchao Yang ◽  
Longwu Wang ◽  
Yu-Cheng Hsu ◽  
Anton Antonov ◽  
Arne Moksnes ◽  
...  
Keyword(s):  
Egg Discrimination ◽  
Brood Parasites ◽  
Uv Reflectance

scholarly journals Synthesis and Structural Studies of Some Inorganic Polymers of Succinoyl Carboxymethyl Cellulose

2011 ◽  
Vol 8 (4) ◽  
pp. 1993-1999 ◽  
Author(s):  
H. D. Juneja ◽  
Manisha Joshi ◽  
N. T. KhatiI
Keyword(s):  
Ir Spectroscopy ◽  
Carboxymethyl Cellulose ◽  
Aqueous Media ◽  
Octahedral Geometry ◽  
Planar Geometry ◽  
Inorganic Polymers ◽  
Structural Studies ◽  
Tetrahedral Geometry ◽  
Square Planar ◽  
Uv Reflectance

The inorganic polymers containing transition metals such as Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) were synthesized by using succinoyl carboxymethyl cellulose (SCMC) in aqueous media. The newly synthesized polymers were characterized by elemental analysis, IR spectroscopy, TG analysis, UV reflectance spectra and magnetic moment. On the basis of these studies, the composition of the polymeric unit was found to be [M(II)L]n, [Mʼ(II)L.2H2O]n, {[Mˮ(II)L.2H2O]n H2O}, where M= Zn(II), Mʼ = Mn(II), Ni(II) and Cu(II) and Mˮ = Co(II), L = SCMC ligand. On the basis of instrumental techniques, it has been found that the [Zn(II)(SCMC)]n inorganic polymer has tetrahedral geometry, whereas {[Cu(II)(SCMC)].2H2O}n has square planar geometry and [Mn(II)(SCMC).2H2O]n, {[Co(II)(SCMC).2H2O)].H2O}n and [Ni(II) (SCMC).2H2O]n have octahedral geometry. The decomposition temperatures of the inorganic polymers have been determined by TGA. The TGA reveal that the Mn(II) polymer of SCMC is highly thermally stable than rest of the polymers and these polymers can be used as thermal resisting materials.

The silk tuft web decorations of the orb-weaver Gasteracantha cancriformis : testing the prey attraction and the web advertisement hypotheses

Behaviour ◽  
2008 ◽  
Vol 145 (3) ◽  
pp. 277-295 ◽  
Author(s):  
Felipe Gawryszewski ◽  
Paulo Motta
Keyword(s):  
Drosophila Melanogaster ◽  
Foraging Success ◽  
Uv Reflectance ◽  
Web Advertisement ◽  
Orb Web ◽  
Orb Web Spiders ◽  
Large Animals ◽  
And Control ◽  
The Web ◽  
Prey Attraction

AbstractSeveral orb-web spiders build conspicuous decorations in their webs. The prey attraction hypothesis proposes that decorations increase spider foraging success by attracting prey, and that attraction is linked to UV reflectance. Alternatively, the web advertisement hypothesis proposes that decorations are a signal that advertises the presence of the web to large animals. We tested both hypotheses for the web silk tufts of Gasteracantha cancriformis. Even though tufts are UV reflective, we did not find support for the prey attraction hypothesis. In the field, when webs with tufts painted black and control webs were compared, there were no differences in the number of prey captured, number of damaged areas in webs and type of prey captured. In the laboratory, Drosophila melanogaster did not demonstrate preference for tufted silk lines versus non-tufted silk lines. Our data also did not give support for the web advertisement hypothesis. The proportion of web destruction was similar between web with tufts painted black and control webs during four days of experimentation. Therefore, two of the most favoured hypotheses that attempt to explain decorations do not apply for web silk tufts in our study system. Instead we propose that silk tufts might be an aposematic signal.

scholarly journals Gd3Li3Te2O12:U6+,Eu3+: A Tunable Red Emitting Garnet Showing Efficient U6+ to Eu3+ Energy Transfer at Room Temperature

Inorganics ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 84
Author(s):  
David Böhnisch ◽  
Juri Rosenboom ◽  
Thomas Jansen ◽  
Thomas Jüstel
Keyword(s):  
Energy Transfer ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Fluorescent Light ◽  
Light Sources ◽  
Light Emitting ◽  
Emission Lifetime ◽  
Uv Reflectance ◽  
Inorganic Composition ◽  
Color Rendering

Since the invention of fluorescent light sources, there is strong interest in Eu3+ activated phosphors as they are able to provide a high color rendering index (CRI) and luminous efficacy, which will also hold for phosphor converted light emitting diodes. Due to an efficient U6+ to Eu3+ energy transfer in Gd3Li3Te2O12:U6+,Eu3+, this inorganic composition shows red photoluminescence peaking at 611 nm. That means Eu3+ photoluminescence can be nicely sensitized via excitation into the U6+ excitation bands. Therefore, photoluminescence properties, such as temperature dependent emission and emission lifetime measurements, are presented. Charge transfer bands were investigated in detail. Additionally, density functional theory calculations reveal the band structure of the pure, i.e., non-doped host material. Obtained theoretical results were evaluated experimentally by the aid of diffuse UV reflectance spectroscopy.

scholarly journals Subspecific and Temporal Variation in the Structurally Based Coloration of the Ultramarine Grosbeak

The Condor ◽  
2007 ◽  
Vol 109 (1) ◽  
pp. 187-192 ◽  
Author(s):  
Ana S. Barreira ◽  
Dario A. Lijtmaer ◽  
Stephen C. Lougheed ◽  
Pablo L. Tubaro
Keyword(s):  
Temporal Variation ◽  
Gradual Increase ◽  
Color Variation ◽  
Reflectance Spectra ◽  
Plumage Coloration ◽  
Sexual Dichromatism ◽  
Ambient Light ◽  
Uv Reflectance ◽  
Color Differences ◽  
Dark Blue

Abstract Abstract Ultramarine Grosbeaks (Cyanocompsa brissonii) possess a striking sexual dichromatism, with males dark blue and females brown. There are two subspecies in Argentina: the larger-bodied C. b. argentina, which is common in shrubs and semiopen areas, and the smaller C. b. sterea that inhabits forests. We measured reflectance spectra of six plumage patches from study skins to evaluate the possibility of color differences between males of each subspecies and temporal variation in plumage coloration. We found differences between subspecies in color brightness, hue, saturation, and UV chroma in the plumage patches of more conspicuous coloration, which could be related to ambient light differences between the environments that each subspecies inhabits. We also documented temporal color variation in some plumage patches, in particular a gradual decrease of UV reflectance and a gradual increase in hue after molting, possibly attributable to feather wear.

scholarly journals Is UV signalling involved in male-male territorial conflict in the blue tit (Cyanistes caeruleus)? A new experimental approach

Behaviour ◽  
2007 ◽  
Vol 144 (4) ◽  
pp. 447-470 ◽  
Author(s):  
Thomas Dijkstra ◽  
Peter Korsten ◽  
Jan Komdeur
Keyword(s):  
Experimental Approach ◽  
Bird Species ◽  
Female Mate Choice ◽  
Blue Tit ◽  
Cyanistes Caeruleus ◽  
Fertile Period ◽  
Territorial Conflict ◽  
Uv Reflectance ◽  
Aggressive Reactions ◽  
Uv Coloration

Structurally-based ultraviolet (UV) coloration of plumage can signal male quality and plays a role in female mate choice in many bird species. UV-reflecting badges could also be important signals in male-male competition. We tested if territorial blue tit ( Cyanistes caeruleus ) males discriminate between conspecific male intruders which differ in the UV reflectance of their crown feathers. To this aim, we used a new experimental approach in which we simultaneously (instead of sequentially) introduced two male blue tit taxidermic mounts in the territories of resident males during the female fertile period; one mount with natural crown UV reflectance and one mount with reduced crown UV. The two mounts provoked strong aggressive reactions from resident males. Males specifically directed their aggression to conspecific intruders, as a male blue tit mount received substantially more aggression than a mount of a European robin ( Erithacus rubecula ). However, aggression of resident males did not vary between the UV-reduced and the control mount. Furthermore, the variation in natural crown UV reflectance of the resident males did not predict the intensity of their aggressive response. Contrary to previous findings our results suggest that UV signals play only a limited role in male-male interactions during territorial intrusions in the female fertile period.

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