Spectral Characteristics of Salmonid Migratory Routes from Southern Vancouver Island (British Columbia)

1993 ◽  
Vol 50 (8) ◽  
pp. 1706-1716 ◽  
Author(s):  
Iñigo Novales Flamarique ◽  
Craig W. Hawryshyn
Keyword(s):  
Uv Light ◽  
Spectral Characteristics ◽  
Polarized Light ◽  
Vancouver Island ◽  
Spectral Irradiance ◽  
Atmospheric Conditions ◽  
Chl A ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Light Levels ◽  
Saanich Inlet

Spectral irradiance was measured from 300 to 850 nm under clear and overcast skies in Saanich Inlet and Trevor Channel (Vancouver Island) using an underwater spectroradiometer. The values obtained were corrected for ocular media transmission and pigment absorption of the four visual pigments in small rainbow trout, Oncorhynchus mykiss (UV, short, middle, and long wavelength sensitive), to estimate the light available to stimulate each of these photoreceptors. Light levels were compared with particle counts, Chl a, and dissolved organic matter (DOM) concentrations at various sites and with similar parameters previously measured for freshwater systems. There was sufficient light to stimulate all the photoreceptors down to 15 m, which was the limiting depth in Saanich Inlet for UV cone simulation and for stimulation of the β absorption band of middle wavelength cones. UV light levels diminished with increasing DOM and Chl a concentrations; however, no statistically discernable relationship was found between UV levels and Chl a concentrations with distance from the spawning rivers. Under completely overcast conditions, directionality of the sun's rays is maintained under some types of cloud cover. This indicates that navigation using polarized light may occur under variable atmospheric conditions provided enough polarized light is present in the water column.

scholarly journals The Photic Environment of a Salmontd Nursery Lake

1992 ◽  
Vol 169 (1) ◽  
pp. 121-141 ◽  
Author(s):  
IÑIGO NOVALES-FLAMARIQUE ◽  
ANDREW HENDRY ◽  
CRAIG W. HAWRYSHYN
Keyword(s):  
Light Field ◽  
Relative Proportion ◽  
Spectral Characteristics ◽  
Polarized Light ◽  
Time Of Day ◽  
Water Molecules ◽  
Atmospheric Conditions ◽  
Suspended Particulates ◽  
Scuba Divers ◽  
Depth Restriction

The spectral characteristics of Lake Cowichan (Vancouver Island) were examined using a LiCor underwater spectroradiometer. The results were analyzed in terms of salmonid vision with special emphasis placed on the ultraviolet part of the spectrum. Irradiance measurements were taken by SCUBA divers every 3 m from 18m to the surface at each of seven locations. The measurements at each depth consisted of four scans from 300 to 850 nm of downwelling, upwelling and horizontal light in the sun and antisun directions. The study covered different times of day and variable atmospheric conditions. According to predictions from the absorptive properties of water molecules and scattering by these and suspended particulates, it was found that the ultraviolet part of the spectrum was the least transmitted. The light field varied in intensity and dominant wavelengths depending on direction and time of day. The relative proportion of ultraviolet, short and middle wavelengths with respect to the entire spectrum peaked during crepuscular periods; the opposite was true for long wavelengths. An analysis of the irradiance values with respect to salmonid vision showed that there was enough light to stimulate all the photoreceptor mechanisms found in juvenile salmonid retinae (sensitive to ultraviolet, short, middle and long wavelengths) at all depths studied. Nevertheless, 18 m was found to be the limiting depth for stimulation of the ultraviolet cone mechanism, which is required for perception of ultraviolet polarized light. This depth restriction may be linked to the observed salmonid movements close to the surface during crepuscular periods.

The Nature of Infill Material on the Discontinuities of the Muntele Mare Granite (Beliş-Fantânele, Romania)

2021 ◽  
Author(s):  
Nicolae Har ◽  
Robert Gheorghiu
Keyword(s):  
Slope Stability ◽  
Atmospheric Oxygen ◽  
Polarized Light ◽  
Rock Slope Stability ◽  
Rock Properties ◽  
Iron Hydroxides ◽  
Atmospheric Conditions ◽  
Secondary Phases ◽  
Alteration Processes ◽  
Infill Material

Abstract The stability of rock massifs is strongly influenced by natural degradation processes. In combination with hydrothermal activity or atmospheric exposure, rock alteration processes can lead to the formation of secondary phases that ultimately control the rock quality and slope stability, which are particularly important for engineering works (e.g., road cuts, open pits, quarries, tunnels). The Bozgai open quarry in the Muntele Mare granite massif in the northern Apuseni Mountains (Romania) offers an excellent opportunity to investigate the influence of alteration processes on rock properties, especially owing to the extensive exposure of granite and specific mineral assemblages of hydrothermal genesis to atmospheric conditions. The alteration processes generated secondary phases located on the primary minerals of the affected rocks or deposited as infill material along the granite discontinuities. Natural and oriented samples of the Bozgai quarry infill material were investigated using polarized light, X-ray diffraction, and scanning electron microscopy to obtain images and identify their mineralogical composition. The hydrothermal vein material consists of kaolinite, illite, pyrite, marcasite, quartz, iron hydroxides, albite, and microcline. These samples were exposed to atmospheric oxygen and meteoric water and secondary sulphates (jarosite and gypsum) formed in an acidic environment generated by the oxidization of pyrite and marcasite. The sheeted structure of kaolinite and geochemical behavior of the sulphates in the presence of water play a particularly important role in the reduced rock slope stability in the Bozgai quarry.

scholarly journals Researching CdZnS/ZnS (GT) Quantum Dots in Cathodoluminescent Mode

2019 ◽  
Vol 8 (9S2) ◽  
pp. 841-843
Keyword(s):  
Quantum Dots ◽  
Research And Development ◽  
Uv Light ◽  
Spectral Characteristics ◽  
Light Sources ◽  
Application Field ◽  
Medium Pressure

Application field of UV light sources is getting larger at the last decades. Among the most widespread are high and medium pressure vacuum lamps. But there currently is a trend of moving away from using mercury both in household applications and manufacturing. This creates a necessity to conduct research and development for UV sources made and operating without Hg. Cathodoluminescent UV sources are in this category. One of the possible ways to create a viable UV anode phosphor is using quantum dots with needed spectral characteristics.

scholarly journals Identification of phenolic compounds of dry extract of dandelion herb and large burdock leaf tea

2019 ◽  
Vol 18 (2) ◽  
pp. 73-77
Author(s):  
L. M. Fedoseeva ◽  
Yu. I. Chistova
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Phenolic Compounds ◽  
High Performance ◽  
Uv Light ◽  
Spectral Characteristics ◽  
Water System ◽  
Dry Extract ◽  
Caffeic Acid Derivatives ◽  
Layer Chromatography

The purpose of this work is to study of phenolic compounds in the dry extract of dandelion herb and large burdock leaf tea.Materials and methods . The separation and identification of phenolic compounds of dry extract of dandelion herb and large burdock leaf tea by thin-layer chromatography and high-performance liquid chromatography with UV-detectionhas been carried out.Results . As a result of research, it has been established that during TLC the optimal system for the separation of phenolic compounds is the ethyl acetate – formic acid – water system (10:2:3). On the chromatogram four spots were found corresponding to the value of Rf and fluorescence in UV-light to flavonoids of the flavone group and phenolic acids (chlorogenic and caffeic acids). For further identification of phenolic compounds using HPLC, eight peaks were found, which in terms of retention time and spectral characteristics correspond to phenologlycosides, chlorogenic acid, caffeic acid derivatives, ferulic acid, umbelliferone.Conclusions . Thus, the dry extract of dandelion herb and large burdock leaf tea contains hydroxycinnamic acids and their derivatives, compounds of coumarin nature, phenologlycosides.

scholarly journals Quality assessment of solar UV irradiance measured with array spectroradiometers

2016 ◽  
Vol 9 (4) ◽  
pp. 1553-1567 ◽  
Author(s):  
Luca Egli ◽  
Julian Gröbner ◽  
Gregor Hülsen ◽  
Luciano Bachmann ◽  
Mario Blumthaler ◽  
...  
Keyword(s):  
Spectral Irradiance ◽  
Stray Light ◽  
Atmospheric Conditions ◽  
End User ◽  
Uv Index ◽  
Uv Irradiance ◽  
The World ◽  
Solar Uv ◽  
Solar Uv Irradiance

Abstract. The reliable quantification of ultraviolet (UV) radiation at the earth's surface requires accurate measurements of spectral global solar UV irradiance in order to determine the UV exposure to human skin and to understand long-term trends in this parameter. Array spectroradiometers (ASRMs) are small, light, robust and cost-effective instruments, and are increasingly used for spectral irradiance measurements. Within the European EMRP ENV03 project “Solar UV”, new devices, guidelines and characterization methods have been developed to improve solar UV measurements with ASRMs, and support to the end user community has been provided. In order to assess the quality of 14 end user ASRMs, a solar UV intercomparison was held on the measurement platform of the World Radiation Center (PMOD/WRC) in Davos, Switzerland, from 10 to 17 July 2014. The results of the blind intercomparison revealed that ASRMs, currently used for solar UV measurements, show a large variation in the quality of their solar UV measurements. Most of the instruments overestimate the erythema-weighted UV index – in particular at large solar zenith angles – due to stray light contribution in the UV-B range. The spectral analysis of global solar UV irradiance further supported the finding that the uncertainties in the UV-B range are very large due to stray light contribution in this wavelength range. In summary, the UV index may be detected by some commercially available ASRMs within 5 % compared to the world reference spectroradiometer, if well characterized and calibrated, but only for a limited range of solar zenith angles. Generally, the tested instruments are not yet suitable for solar UV measurements for the entire range between 290 and 400 nm under all atmospheric conditions.

A New Species of Bradyidius (Copepoda: Calanoida) from the Pacific Coast of North America

1966 ◽  
Vol 23 (6) ◽  
pp. 805-811 ◽  
Author(s):  
Tai Soo Park
Keyword(s):  
British Columbia ◽  
New Species ◽  
North America ◽  
Pacific Coast ◽  
Vancouver Island ◽  
Saanich Inlet ◽  
The Pacific ◽  
A New Species

A new species Bradyidius saanichi from Saanich Inlet, Vancouver Island, British Columbia, Canada, is described and illustrated in detail. This species is closely related to B. pacificus (Brodsky, 1950) among the six previously known species in the genus, but can be readily distinguished from the latter by the strongly divergent rostral rami in addition to some other differences.

scholarly journals An unsuccessful attempt to elicit orientation responses to linearly polarized light in hatchling loggerhead sea turtles ( Caretta caretta )

2011 ◽  
Vol 366 (1565) ◽  
pp. 757-762 ◽  
Author(s):  
Lydia M. Mäthger ◽  
Kenneth J. Lohmann ◽  
Colin J. Limpus ◽  
Kerstin A. Fritsches
Keyword(s):  
Light Field ◽  
Uv Light ◽  
Light Emitting Diode ◽  
Sea Turtles ◽  
Polarized Light ◽  
Caretta Caretta ◽  
Polarization Sensitivity ◽  
Light Perception ◽  
Unsuccessful Attempt ◽  
Swimming Direction

Sea turtles undertake long migrations in the open ocean, during which they rely at least partly on magnetic cues for navigation. In principle, sensitivity to polarized light might be an additional sensory capability that aids navigation. Furthermore, polarization sensitivity has been linked to ultraviolet (UV) light perception which is present in sea turtles. Here, we tested the ability of hatchling loggerheads ( Caretta caretta ) to maintain a swimming direction in the presence of broad-spectrum polarized light. At the start of each trial, hatchling turtles, with their magnetic sense temporarily impaired by magnets, successfully established a steady course towards a light-emitting diode (LED) light source while the polarized light field was present. When the LED was removed, however, hatchlings failed to maintain a steady swimming direction, even though the polarized light field remained. Our results have failed to provide evidence for polarized light perception in young sea turtles and suggest that alternative cues guide the initial migration offshore.

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