On the spectral composition of atmospheric turbulent optical distortions from observations on solar telescopes

2017 ◽  
Author(s):  
Pavel Kovadlo ◽  
Vladimir Lukin ◽  
Dmitriy Kolobov ◽  
Victor Nosov ◽  
Maksim Eselevich ◽  
...  
Keyword(s):  
Spectral Composition ◽  
Solar Telescopes

Amplitude Distributions of Cochlear Microphonic Response to an Acoustic Sinusoid in Noise

1968 ◽  
Vol 11 (1) ◽  
pp. 63-76
Author(s):  
Donald C. Teas ◽  
Gretchen B. Henry
Keyword(s):  
Small Amplitude ◽  
Basilar Membrane ◽  
Spectral Composition ◽  
Pass Band ◽  
Cochlear Microphonic ◽  
Filter Output ◽  
Electronic Filter ◽  
Low Pass ◽  
Band Pass ◽  
Instantaneous Voltage

The distributions of instantaneous voltage amplitudes in the cochlear microphonic response recorded from a small segment along the basilar membrane are described by computing amplitude histograms. Comparisons are made between the distributions for noise and for those after the addition to the noise of successively stronger sinusoids. The amplitudes of the cochlear microphonic response to 5000 Hz low-pass noise are normally distributed in both Turn I and Turn III of the guinea pig’s cochlea. The spectral composition of the microphonic from Turn I and from Turn III resembles the output of band-pass filters set at about 4000 Hz, and about 500 Hz, respectively. The normal distribution of cochlear microphonic amplitudes for noise is systematically altered by increasing the strength of the added sinusoid. A decrease of three percent in the number of small amplitude events (±1 standard deviation) in the cochlear microphonic from Turn III is seen when the rms voltage of a 500 Hz sinusoid is at −18 dB re the rms voltage of the noise (at the earphone). When the rms of the sinusoid and noise are equal, the decrease in small voltages is about 25%, but there is also an increase in the number of large voltage amplitudes. Histograms were also computed for the output of an electronic filter with a pass-band similar to Turn III of the cochlea. Strong 500 Hz sinusoids showed a greater proportion of large amplitudes in the filter output than in CM III . The data are interpreted in terms of an anatomical substrate.

DESIGN OF THE VIRTUAL DEVICE FOR THE SIGNAL SPECTRUM CALCULATION IN THE LABVIEW ENVIRONMENT

2019 ◽  
Author(s):  
Tossenko O.M.
Keyword(s):  
Virtual Instrument ◽  
Spectral Characteristics ◽  
Spectral Composition ◽  
Automated System ◽  
Signal Spectrum ◽  
Measuring Instruments ◽  
Specific Information ◽  
Measuring Device ◽  
Virtual Device ◽  
Graphical Tool

The development of measuring instruments requires a specialist to know the principles of operation of advanced measuring systems. This article describes guidelines for creating a virtual appliance in LabVIEW. LabVIEW (Laboratory Virtual Instrument Engineering Workbench) is a graphical application programming environment used as a standard tool for measuring, analyzing their data, further ma­ naging devices and objects under study. LabVIEW language is not like other programming languages. It does not create a program, but a virtual tool, designed not only for the simulation of certain processes, but also for the management of hardware and the study of real physical objects. The article deals with the task of designing application software for a specific information-measuring device, analyzes the capabilities of the LabVIEW environment for spectral analysis of various signals, outlines the basic principles and techniques of programming within the framework of the LabVIEW graphical environment during the basic stages of development. The procedure for creating a virtual device is described, which allows to evaluate the spectral composition of the signals, presents a graphical code of execution (diagram) to the program and a graphical tool interface of the virtual device. A number of basic elements used to develop the program are described. The simplicity of the graphic designs, the ease of installation on the field of the program, the clarity and readability of the program — all of which makes LabVIEW preferred over other languages of programming. In most cases, the experiment is the only source of reliable information. And the result is achieved much faster than the methods of "pure" theory. The article substantiates the effectiveness of using a development tool that allows to obtain a software product and ensure the fulfillment of all the basic functions of an automated system. Developing a software algorithm for calculating statistical parameters will help engineering students understand the order of determining spectral characteristics and their place in the structure of experimental research.

scholarly journals In search of the spectral composition of an effective light trap for the mushroom pest Lycoriella ingenua (Diptera: Sciaridae)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sándor Kecskeméti ◽  
András Geösel ◽  
József Fail ◽  
Ádám Egri
Keyword(s):  
Light Intensity ◽  
Spectral Sensitivity ◽  
Fungal Pathogens ◽  
Light Trap ◽  
Spectral Composition ◽  
Wavelength Dependence ◽  
Crop Damage ◽  
Photon Flux ◽  
Compound Eyes ◽  
Behavioural Experiments

AbstractCertain fungus gnats, like Lycoriella ingenua are notorious pests in agriculture, especially in mushroom production. While larvae cause mainly direct crop damage, adults are vectors of several dangerous fungal pathogens. To promote the development of pesticide-free management methods, such as light trapping, we measured the spectral sensitivity of L. ingenua compound eyes with electroretinography and performed two different behavioural experiments to reveal the wavelength dependence of phototaxis in this species. The spectral sensitivity of the compound eyes is bimodal with peaks at 370 nm (UV) and 526 nm (green). Behavioural experiments showed that attraction to light as a function of wavelength depends on light intensity. In our first experiment, where the minimal photon flux (105–109 photons/cm2/s) needed for eliciting a phototactic response was determined wavelength by wavelength, phototaxis was strongest in the green spectral range (~526 nm). In the other behavioural experiment, where wavelength preference was tested under a higher but constant light intensity (~1013 photons/cm2/s), the highest attraction was elicited by UV wavelengths (398 nm). Our results suggest that both UV and green are important spectral regions for L. ingenua thus we recommend to use both UV (~370-398 nm) and green (~526 nm) for trapping these insects.

scholarly journals The Role of Selected Wavelengths of Light in the Activity of Photosystem II in Gloeobacter violaceus

2021 ◽  
Vol 22 (8) ◽  
pp. 4021
Author(s):  
Monika Kula-Maximenko ◽  
Kamil Jan Zieliński ◽  
Ireneusz Ślesak
Keyword(s):  
Photosystem Ii ◽  
Spectral Composition ◽  
Photosynthetic Electron Transport ◽  
Metabolic Energy ◽  
Light Conditions ◽  
Gloeobacter Violaceus ◽  
Transport Chain ◽  
Cyanobacterial Culture ◽  
Photosynthetic Antennas

Gloeobacter violaceus is a cyanobacteria species with a lack of thylakoids, while photosynthetic antennas, i.e., phycobilisomes (PBSs), photosystem II (PSII), and I (PSI), are located in the cytoplasmic membrane. We verified the hypothesis that blue–red (BR) light supplemented with a far-red (FR), ultraviolet A (UVA), and green (G) light can affect the photosynthetic electron transport chain in PSII and explain the differences in the growth of the G. violaceus culture. The cyanobacteria were cultured under different light conditions. The largest increase in G. violaceus biomass was observed only under BR + FR and BR + G light. Moreover, the shape of the G. violaceus cells was modified by the spectrum with the addition of G light. Furthermore, it was found that both the spectral composition of light and age of the cyanobacterial culture affect the different content of phycobiliproteins in the photosynthetic antennas (PBS). Most likely, in cells grown under light conditions with the addition of FR and G light, the average antenna size increased due to the inactivation of some reaction centers in PSII. Moreover, the role of PSI and gloeorhodopsin as supplementary sources of metabolic energy in the G. violaceus growth is discussed.

scholarly journals Ocular growth and metabolomics are dependent upon the spectral content of ambient white light

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Raymond P. Najjar ◽  
Juan Manuel Chao De La Barca ◽  
Veluchamy A. Barathi ◽  
Candice Ee Hua Ho ◽  
Jing Zhan Lock ◽  
...  
Keyword(s):  
Critical Role ◽  
Spectral Composition ◽  
Light Therapy ◽  
World Population ◽  
Spectral Content ◽  
Ocular Growth ◽  
Nitric Oxide Metabolism ◽  
Therapy Strategies ◽  
Indoor Lighting ◽  
The Impact

AbstractMyopia results from an excessive axial growth of the eye, causing abnormal projection of remote images in front of the retina. Without adequate interventions, myopia is forecasted to affect 50% of the world population by 2050. Exposure to outdoor light plays a critical role in preventing myopia in children, possibly through the brightness and blue-shifted spectral composition of sunlight, which lacks in artificial indoor lighting. Here, we evaluated the impact of moderate levels of ambient standard white (SW: 233.1 lux, 3900 K) and blue-enriched white (BEW: 223.8 lux, 9700 K) lights on ocular growth and metabolomics in a chicken-model of form-deprivation myopia. Compared to SW light, BEW light decreased aberrant ocular axial elongation and accelerated recovery from form-deprivation. Furthermore, the metabolomic profiles in the vitreous and retinas of recovering form-deprived eyes were distinct from control eyes and were dependent on the spectral content of ambient light. For instance, exposure to BEW light was associated with deep lipid remodeling and metabolic changes related to energy production, cell proliferation, collagen turnover and nitric oxide metabolism. This study provides new insight on light-dependent modulations in ocular growth and metabolomics. If replicable in humans, our findings open new potential avenues for spectrally-tailored light-therapy strategies for myopia.

scholarly journals The Preferences of Different Cultivars of Lettuce Seedlings (Lactuca sativa L.) for the Spectral Composition of Light

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1211
Author(s):  
Barbara Frąszczak ◽  
Monika Kula-Maximenko
Keyword(s):  
Chlorophyll Content ◽  
Blue Light ◽  
White Light ◽  
Leaf Shape ◽  
Red Light ◽  
Spectral Composition ◽  
Fresh Weight ◽  
Light Spectrum ◽  
Dark Green ◽  
Relative Chlorophyll Content

The spectrum of light significantly influences the growth of plants cultivated in closed systems. Five lettuce cultivars with different leaf colours were grown under white light (W, 170 μmol m−2 s−1) and under white light with the addition of red (W + R) or blue light (W + B) (230 μmol m−2 s−1). The plants were grown until they reached the seedling phase (30 days). Each cultivar reacted differently to the light spectrum applied. The red-leaved cultivar exhibited the strongest plasticity in response to the spectrum. The blue light stimulated the growth of the leaf surface in all the plants. The red light negatively influenced the length of leaves in the cultivars, but it positively affected their number in red and dark-green lettuce. It also increased the relative chlorophyll content and fresh weight gain in the cultivars containing anthocyanins. When the cultivars were grown under white light, they had longer leaves and higher value of the leaf shape index. The light-green cultivars had a greater fresh weight. Both the addition of blue and red light significantly increased the relative chlorophyll content in the dark-green cultivar. The spectrum enhanced with blue light had positive influence on most of the parameters under analysis in butter lettuce cultivars. These cultivars were also characterised by the highest absorbance of blue light.

Spectral composition of artificial illuminants and their effect on eye growth in chicks

2021 ◽  
pp. 108602
Author(s):  
Hannah Yoon ◽  
Christopher P. Taylor ◽  
Frances Rucker
Keyword(s):  
Spectral Composition ◽  
Eye Growth
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