A Device to Simulate the Variability in Sunlight Intensity for Laboratory Cultures of Algae

1978 ◽  
Vol 35 (8) ◽  
pp. 1152-1154 ◽  
Author(s):  
Carl M. Boyd ◽  
John Marra
Keyword(s):  
Light Intensity ◽  
Key Words ◽  
Light Source ◽  
Diurnal Rhythms ◽  
Continuous Control ◽  
Environmental Light ◽  
Laboratory Cultures ◽  
Variable Light ◽  
Sunlight Intensity ◽  
Key Words Light Intensity

Simulation in the laboratory of the variability of environmental light intensity is achieved by automatic continuous control of voltage applied to a tungsten light source. Key words: light intensity, variable light, photosynthesis, diurnal rhythms

Ambient light intensity and direction determine relative attractiveness of yellow traps toRhagoletis indifferens(Diptera: Tephritidae)

2015 ◽  
Vol 147 (6) ◽  
pp. 776-786 ◽  
Author(s):  
W.L. Yee
Keyword(s):  
Light Intensity ◽  
Fruit Fly ◽  
Ambient Light ◽  
Laboratory Results ◽  
Yellow Traps ◽  
Relative Attractiveness ◽  
Variable Light ◽  
Sunlight Intensity ◽  
Trap Placement ◽  
Tephritid Fruit Flies

AbstractUnderstanding factors that influence attraction of tephritid fruit flies (Diptera: Tephritidae) to objects can lead to development of more sensitive traps for fly detection. Here, the objective was to determine if differences in attractiveness between two sticky yellow rectangle traps to western cherry fruit fly,Rhagoletis indifferensCurran, depend on ambient light intensity and direction. The translucent plastic Yellow Sticky Strip (YSS) was compared with the less translucent yellow cardboard Alpha Scents (AS). Flies were released inside a box or cage opposite a trap or traps illuminated from outside at different intensities to generate variable light passage. Regardless of type, the trap with greatest light passage was most attractive. When the same light intensity was shone on both traps, the YSS, which allowed greater light passage, was more attractive than the AS. When the light was inside a cage and shone onto the two traps in the same direction as approaching flies, the AS reflected more light and was more attractive. A field experiment generally supported light passage effects seen in the laboratory. Results suggest trap placement with respect to sunlight intensity and direction affects light passage and the attractiveness of yellow traps toR. indifferens.

Fine structure of the retina of the giant scallop, Placopecten magellanicus

1984 ◽  
Vol 42 ◽  
pp. 312-313
Author(s):  
C.V.L. Powell
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Light Intensity ◽  
Scanning Electron Microscope ◽  
Eye Development ◽  
Preliminary Observation ◽  
Columnar Epithelium ◽  
Placopecten Magellanicus ◽  
Environmental Light ◽  
Scanning Electron

The overall fine structure of the eye in Placopecten is similar to that of other scallops. The optic tentacle consists of an outer columnar epithelium which is modified into a pigmented iris and a cornea (Fig. 1). This capsule encloses the cellular lens, retina, reflecting argentea and the pigmented tapetum. The retina is divided into two parts (Fig. 2). The distal retina functions in the detection of movement and the proximal retina monitors environmental light intensity. The purpose of the present study is to describe the ultrastructure of the retina as a preliminary observation on eye development. This is also the first known presentation of scanning electron microscope studies of the eye of the scallop.

Inter-Method Reliability of Pulse Volume Related Measures Derived Using Finger-Photoplethysmography

2018 ◽  
Vol 32 (4) ◽  
pp. 182-190 ◽  
Author(s):  
Kenta Matsumura ◽  
Koichi Shimizu ◽  
Peter Rolfe ◽  
Masanori Kakimoto ◽  
Takehiro Yamakoshi
Keyword(s):  
Light Intensity ◽  
Adverse Effects ◽  
Light Source ◽  
Direct Current ◽  
Resting State ◽  
Current Component ◽  
Psychophysiological Measures ◽  
Pulse Volume ◽  
Optical Paths ◽  
Sensor Positions

Abstract. Pulse volume (PV) and its related measures, such as modified normalized pulse volume (mNPV), direct-current component (DC), and pulse rate (PR), derived from the finger-photoplethysmogram (FPPG), are useful psychophysiological measures. Although considerable uncertainties exist in finger-photoplethysmography, little is known about the extent of the adverse effects on the measures. In this study, we therefore examined the inter-method reliability of each index across sensor positions and light intensities, which are major disturbance factors of FPPG. From the tips of the index fingers of 12 participants in a resting state, three simultaneous FPPGs having overlapping optical paths were recorded, with their light intensity being changed in three steps. The analysis revealed that the minimum values of three coefficients of Cronbach’s α for ln PV, ln mNPV, ln DC, and PR across positions were .948, .850, .922, and 1.000, respectively, and that those across intensities were .774, .985, .485, and .998, respectively. These findings suggest that ln mNPV and PR can be used for psychophysiological studies irrespective of minor differences in sensor attachment positions and light source intensity, whereas and ln DC can also be used for such studies but under the condition of light intensity being fixed.

scholarly journals Cyanobacteria use micro-optics to sense light direction

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Nils Schuergers ◽  
Tchern Lenn ◽  
Ronald Kampmann ◽  
Markus V Meissner ◽  
Tiago Esteves ◽  
...  
Keyword(s):  
Light Intensity ◽  
Light Source ◽  
Type Iv Pili ◽  
Small Cells ◽  
Unicellular Cyanobacterium ◽  
Light Sensing ◽  
High Resolution Image ◽  
Type Iv ◽  
Micro Optics ◽  
Synechocystis Sp

Bacterial phototaxis was first recognized over a century ago, but the method by which such small cells can sense the direction of illumination has remained puzzling. The unicellular cyanobacterium Synechocystis sp. PCC 6803 moves with Type IV pili and measures light intensity and color with a range of photoreceptors. Here, we show that individual Synechocystis cells do not respond to a spatiotemporal gradient in light intensity, but rather they directly and accurately sense the position of a light source. We show that directional light sensing is possible because Synechocystis cells act as spherical microlenses, allowing the cell to see a light source and move towards it. A high-resolution image of the light source is focused on the edge of the cell opposite to the source, triggering movement away from the focused spot. Spherical cyanobacteria are probably the world’s smallest and oldest example of a camera eye.

scholarly journals The Effects of Day Length and Light Intensity on Tile Growth of Barley

1969 ◽  
Vol 22 (1) ◽  
pp. 53 ◽  
Author(s):  
D Aspinall
Keyword(s):  
Light Intensity ◽  
Linear Relationship ◽  
Light Source ◽  
Blue Light ◽  
Floral Development ◽  
Red Light ◽  
Day Length

The acceleration of flowering in barley due to the inclusion of incandescent illumination in the light source has been shown to be due to the far�red content of the light. A linear relationship between floral development and intensity of far�red light in a 16�hr photoperiod has been established with the cultivar CI5611. Barley appears to be relatively unresponsive to blue light, however.

scholarly journals Gradual Increase in Environmental Light Intensity Induces Oxidative Stress and Inflammation and Accelerates Retinal Neurodegeneration

2020 ◽  
Vol 61 (10) ◽  
pp. 1
Author(s):  
Oksana Kutsyr ◽  
Xavier Sánchez-Sáez ◽  
Natalia Martínez-Gil ◽  
Emilio de Juan ◽  
Pedro Lax ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Light Intensity ◽  
Gradual Increase ◽  
Environmental Light ◽  
Retinal Neurodegeneration

Study on Color Variable Light-Source System Using LCD

2000 ◽  
Vol 84 (Appendix) ◽  
pp. 228-228
Author(s):  
Yoshinori Kohmoto ◽  
Seiki Ohnishi ◽  
Masafumi Jinno ◽  
Masaharu Aono
Keyword(s):  
Light Source ◽  
Variable Light

Sensitive Detection of Ambient Formaldehyde by Incoherent Broadband Cavity Enhanced Absorption Spectroscopy

2020 ◽  
Author(s):  
Jingwei Liu ◽  
Xin Li ◽  
Yiming Yang ◽  
Haichao Wang ◽  
Cailing Kuang ◽  
...  
Keyword(s):  
Light Intensity ◽  
Light Source ◽  
Absorption Spectroscopy ◽  
Fiber Bundle ◽  
Ambient Air ◽  
Optical Path ◽  
Enhanced Absorption ◽  
Cavity Enhanced Absorption Spectroscopy ◽  
Near Ultraviolet ◽  
Type Fiber

<p>Formaldehyde (HCHO) is the most abundant atmospheric carbonyl compound and plays an important role in the troposphere. However, HCHO detection via traditional incoherent broadband cavity enhanced absorption spectroscopy (IBBCEAS) is limited by short optical path lengths and weak light intensity. Thus, a new light-emitting diode (LED)-based IBBCEAS was developed herein to measure HCHO in ambient air. Two LEDs (325 and 340 nm) coupled by a Y-type fiber bundle were used as an IBBCEAS light source, which provided both high light intensity and a wide spectral fitting range. The reflectivity of the two cavity mirrors used herein was 0.99965 (1 – reflectivity = 350 ppm loss) at 350 nm, which corresponded with an effective optical path length of 2.15 km within a 0.84 m cavity. At an integration time of 30 s, the measurement precision (1σ) for HCHO was 380 parts per trillion volume (pptv) and the corresponding uncertainty was 8.3%. The instrument was successfully deployed for the first time in a field campaign and delivered results that correlated well with those of a commercial wet-chemical instrument based on Hantzsch fluorimetry (R<sup>2</sup> = 0.769). The combined light source based on Y-type fiber bundle overcomes the difficulty of measuring ambient HCHO via IBBCEAS in near-ultraviolet range, which may extend IBBCEAS technology to measure other atmospheric trace gases with high precision.</p>

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