scholarly journals Development of swimming speed and schooling behavior of juvenile white rockfish (Sebastes cheni) in relation to ambient light intensity

2015 ◽  
Vol 113 (2) ◽  
pp. 121-128 ◽  
Author(s):  
Hikaru Nakano ◽  
Koji Hirakawa ◽  
Jun Shoji
Keyword(s):  
Light Intensity ◽  
Swimming Speed ◽  
Ambient Light ◽  
Schooling Behavior ◽  
Sebastes Cheni

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.

scholarly journals Optimizing rearing and welfare in Senegalese sole (Solea senegalesensis) broodstock: Effect of ambient light intensity and handling time on stress response

2020 ◽  
Vol 222 ◽  
pp. 104880 ◽  
Author(s):  
Filipe Figueiredo ◽  
Cláudia Aragão ◽  
Wilson Pinto ◽  
Maria Teresa Dinis ◽  
Catarina C.V. Oliveira
Keyword(s):  
Stress Response ◽  
Light Intensity ◽  
Handling Time ◽  
Senegalese Sole ◽  
Ambient Light

The effects of handling time, ambient light, and anaesthetic method, on the standardized measurement of fish colouration

2011 ◽  
Vol 68 (2) ◽  
pp. 330-342 ◽  
Author(s):  
Suzanne M. Gray ◽  
Francine L. Hart ◽  
Maude E.M. Tremblay ◽  
Thomas J. Lisney ◽  
Craig W. Hawryshyn
Keyword(s):  
Light Intensity ◽  
Spectral Reflectance ◽  
Handling Time ◽  
Ambient Light ◽  
Clove Oil ◽  
Ambient Conditions ◽  
Light Levels ◽  
Standardized Measurement ◽  
Colour Patterns ◽  
Reflectance Data

The effects of handling time, ambient light intensity, and anaesthetic method, on the collection of spectral reflectance data were assessed in two species of Malawi cichlids ( Melanochromis auratus and Metriaclima zebra ). Using spectrometry, colour patches were measured over 10 min, under increasing ambient light levels, and using three anaesthetic methods. As time elapsed, maximum percent reflectance (Rmax) decreased across all anaesthetic methods and species, suggesting that measurements should be taken immediately after capture and anaesthetization. With increasing light intensity, Rmax increased significantly, suggesting that measurements should be taken under natural ambient conditions when possible. Finally, we found that anaesthetizing fish using an ice bath produced significantly higher Rmax than using either MS-222 (tricaine methanesulphonate) or clove oil (eugenol). However, the highest proportion of ultraviolet (UV) colouration was recorded while fish were anaesthetized with clove oil. Our results highlight the variation involved in measuring fish colour patterns using two related species, and thus indicate the need for a standardized approach to collecting spectral reflectance data in fish.

scholarly journals Acute Effects of Morning Light on Plasma Glucose and Triglycerides in Healthy Men and Men with Type 2 Diabetes

2017 ◽  
Vol 32 (2) ◽  
pp. 130-142 ◽  
Author(s):  
Ruth I. Versteeg ◽  
Dirk J. Stenvers ◽  
Dana Visintainer ◽  
Andre Linnenbank ◽  
Michael W. Tanck ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Light Intensity ◽  
Plasma Glucose ◽  
Bright Light ◽  
Metabolic Effects ◽  
Ambient Light ◽  
Acute Effects ◽  
Postprandial Plasma Glucose ◽  
Glucose Levels

Ambient light intensity is signaled directly to hypothalamic areas that regulate energy metabolism. Observational studies have shown associations between ambient light intensity and plasma glucose and lipid levels, but human data on the acute metabolic effects of light are scarce. Since light is the main signal indicating the onset of the diurnal phase of physical activity and food intake in humans, we hypothesized that bright light would affect glucose and lipid metabolism. Therefore, we determined the acute effects of bright light on plasma glucose and lipid concentrations in 2 randomized crossover trials: (1) in 8 healthy lean men and (2) in 8 obese men with type 2 diabetes. From 0730 h, subjects were exposed to either bright light (4000 lux) or dim light (10 lux) for 5 h. After 1 h of light exposure, subjects consumed a 600-kcal mixed meal. Primary endpoints were fasting and postprandial plasma glucose levels. In healthy men, bright light did not affect fasting or postprandial plasma glucose levels. However, bright light increased fasting and postprandial plasma triglycerides. In men with type 2 diabetes, bright light increased fasting and postprandial glucose levels. In men with type 2 diabetes, bright light did not affect fasting triglyceride levels but increased postprandial triglyceride levels. We show that ambient light intensity acutely affects human plasma glucose and triglyceride levels. Our findings warrant further research into the consequences of the metabolic effects of light for the diagnosis and prevention of hyperglycemia and dyslipidemia.

scholarly journals Photochemical Acclimation of Three Contrasting Species to Different Light Levels: Implications for Optimizing Supplemental Lighting

2017 ◽  
Vol 142 (5) ◽  
pp. 346-354 ◽  
Author(s):  
Shuyang Zhen ◽  
Marc W. van Iersel
Keyword(s):  
Electron Transport ◽  
Light Intensity ◽  
Photochemical Efficiency ◽  
Light Response ◽  
High Light ◽  
Photon Flux ◽  
Ambient Light ◽  
Response Curves ◽  
Low Light ◽  
Supplemental Lighting

Photosynthetic responses to light are dependent on light intensity, vary among species, and can be affected by acclimation to different light environments (e.g., light intensity, spectrum, and photoperiod). Understanding how these factors affect photochemistry is important for improving supplemental lighting efficiency in controlled-environment agriculture. We used chlorophyll fluorescence to determine photochemical light response curves of three horticultural crops with contrasting light requirements [sweetpotato (Ipomea batatas), lettuce (Lactuca sativa), and pothos (Epipremnum aureum)]. We also quantified how these responses were affected by acclimation to three shading treatments-full sun, 44% shade, and 75% shade. The quantum yield of photosystem II (ΦPSII), a measure of photochemical efficiency, decreased exponentially with increasing photosynthetic photon flux (PPF) in all three species. By contrast, linear electron transport rate (ETR) increased asymptotically with increasing PPF. Within each shading level, the high-light-adapted species sweetpotato used high light more efficiently for electron transport than light-intermediate lettuce and shade-tolerant pothos. Within a species, plants acclimated to high light (full sun) tended to have higher ΦPSII and ETR than those acclimated to low light (44% or 75% shade). Nonphotochemical quenching (NPQ) (an indicator of the amount of absorbed light energy that is dissipated as heat) was upregulated with increasing PPF; faster upregulation was observed in pothos as well as in plants grown under 75% shade. Our results have implications for supplemental lighting: supplemental light is used more efficiently and results in a greater increase in ETR when provided at low ambient PPF. In addition, high-light-adapted crops and crops grown under relatively high ambient light can use supplemental light more efficiently than low-light-adapted crops or those grown under low ambient light.

scholarly journals 766 PB 316 INFLUENCE OF PHOTOPERIOD AND LIGHT INTENSITY ON PLANT HEIGHT OF LILIUM LONGIFLORUM THUNB

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 542f-542
Author(s):  
Theo J. Blom ◽  
M.J. Tsujita ◽  
Glen L. Roberts
Keyword(s):  
Light Intensity ◽  
Plant Height ◽  
Lilium Longiflorum ◽  
Light Period ◽  
Ambient Light ◽  
Dark Light ◽  
Light Reduction ◽  
Potted Plants

Potted plants of Lilium longiflorum Thunb. cvs. `Ace' and `Nellie White' were grown either under an ambient photoperiod (APP) or under an 8-hour photoperiod (8PP) in a greenhouse. The latter photoperiod was achieved by pulling black cloth over the plants at 1615HR and removing the cloth at 0615HR each day, from emergence to flowering. Within each photoperiod, ambient light intensity was reduced by 0, 20, 40 or 60% using various shade cloths permanently suspended above the plants. Heating was set at 20/16C for the dark/light period, respectively. Plant height, determined from the rim of pot to the top of plant, was 25% lower under 8PP compared to APP for both cultivars. Plant height of `Ace' and `Nellie White' increased by 1.5 mm and 2.5 mm, respectively, per 1% light reduction.

scholarly journals Measurement of spring constants of various spring-mass systems by using smartphones: a teaching proposal

2020 ◽  
pp. 1-10
Author(s):  
Mustafa EROL ◽  
Kadir Hocaoğlu ◽  
Şeyda Kaya
Keyword(s):  
Light Intensity ◽  
Relative Error ◽  
Ambient Light ◽  
Mass System ◽  
Harmonic Motion ◽  
Simple Harmonic Motion ◽  
System A ◽  
Light Sensor ◽  
Spring Constants ◽  
Theoretical Results

This study aims to develop a teaching proposal to measure spring constants of various spring-mass systems by means of the smartphones. Specifically, a single spring-mass system, a serial connected and a parallel connected spring systems are experi-mentally resolved, by using the ambient light sensor of the smartphones. The measurements are achieved by simply recording the light intensity, detected by the oscillating smartphone, as a function of time for the simple harmonic motion. Using the light intensity-time graphs, the average periods and eventually the spring constants are estimated and the outcomes are compared with the theoretical results. The overall outcomes of the work indicate some 3,3 % relative error for the serial connected springs and 10,8 % relative error for the parallel connected springs. The approach is important in the sense that the apparatus directly plots instantaneous momentum-time graphs and it creates an enjoyable and beneficial teaching atmosphere.

scholarly journals Automatic headlight controlling of vehicle using ambient light sensor based on phototransistor

2021 ◽  
Author(s):  
Kazi Muhammad Fahim Shahriar
Keyword(s):  
Light Intensity ◽  
Efficient Method ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Ambient Light ◽  
Light Sensor

This paper proposes an efficient method to control the headlight intensity of the vehicle using ambient light sensor (ALS) based on phototransistor with the principle of pulse width modulation. The main responsibility of this automatic headlight control is to control the intensity of the headlight based on the ambient light. The intensity of the headlight will be low when the ambient light intensity is high and vice versa.

scholarly journals Roles of Chemosensory Pathways in Transient Changes in Swimming Speed of Rhodobacter sphaeroides Induced by Changes in Photosynthetic Electron Transport

1999 ◽  
Vol 181 (1) ◽  
pp. 34-39 ◽  
Author(s):  
Simona Romagnoli ◽  
Judith P. Armitage
Keyword(s):  
Electron Transport ◽  
Light Intensity ◽  
Rhodobacter Sphaeroides ◽  
Swimming Speed ◽  
Photosynthetic Electron Transport ◽  
Free Swimming ◽  
Chemosensory Pathway ◽  
Transposon Mutants ◽  
Transport Inhibitors ◽  
Chemosensory Pathways

ABSTRACT The response of free-swimming Rhodobacter sphaeroidesto increases and decreases in the intensity of light of different wavelengths was analyzed. There was a transient (1 to 2 s) increase in swimming speed in response to an increase in light intensity, and there was a similar transient stop when the light intensity decreased. Measurement of changes in membrane potential and the use of electron transport inhibitors showed that the transient increase in swimming speed, following an increase in light intensity, and the stop following its decrease were the result of changes in photosynthetic electron transport. R. sphaeroides has two operons coding for multiple homologs of the enteric chemosensory genes. Mutants in the first chemosensory operon showed wild-type photoresponses. Mutants with the cheA gene of the second operon (cheA II) deleted, either with or without the first operon present, showed inverted photoresponses, with free-swimming cells stopping on an increase in light intensity and increasing swimming speed on a decrease. These mutants also lacked adaptation. Transposon mutants with mutations incheA II, which also reduced expression of downstream genes, however, showed no photoresponses. These results show that (i) free-swimming cells respond to both an increase and a decrease in light intensity (tethered cells only show the stopping on a step down in light intensity), (ii) the signal comes from photosynthetic electron transfer, and (iii) the signal is primarily channelled through the second chemosensory pathway. The different responses shown by thecheA II deletion and insertion mutants suggest that CheWII is required for photoresponses, and a third sensory pathway can substitute for CheAII as long as CheWII is present. The inverted response suggests that transducers are involved in photoresponses as well as chemotactic responses.

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