33 CFR 84.15 - Intensity of lights.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Intensity of lights. 84.15... NAVIGATION RULES ANNEX I: POSITIONING AND TECHNICAL DETAILS OF LIGHTS AND SHAPES § 84.15 Intensity of lights. (a) The minimum luminous intensity of lights shall be calculated by using the formula: I=3.43×106×T...

14 CFR 29.1389 - Position light distribution and intensities.

Code of Federal Regulations, 2010 CFR

2010-01-01

... terms of minimum intensities in the horizontal plane, minimum intensities in any vertical plane, and... requirements: (1) Intensities in the horizontal plane. Each intensity in the horizontal plane (the plane containing the longitudinal axis of the rotorcraft and perpendicular to the plane of symmetry of the...

14 CFR 27.1389 - Position light distribution and intensities.

Code of Federal Regulations, 2010 CFR

2010-01-01

... minimum intensities in the horizontal plane, minimum intensities in any vertical plane, and maximum...: (1) Intensities in the horizontal plane. Each intensity in the horizontal plane (the plane containing the longitudinal axis of the rotorcraft and perpendicular to the plane of symmetry of the rotorcraft...

14 CFR 25.1389 - Position light distribution and intensities.

Code of Federal Regulations, 2010 CFR

2010-01-01

... minimum intensities in the horizontal plane, minimum intensities in any vertical plane, and maximum...: (1) Intensities in the horizontal plane. Each intensity in the horizontal plane (the plane containing the longitudinal axis of the airplane and perpendicular to the plane of symmetry of the airplane) must...

Effect of inhomogeneity of light from light curing units on the surface hardness of composite resin.

PubMed

Arikawa, Hiroyuki; Kanie, Takahito; Fujii, Koichi; Takahashi, Hideo; Ban, Seiji

2008-01-01

This study investigated the characteristics of output light from different types of light curing units, and their effects on polymerization of light-activated composite resin. Three quartz-tungsten-halogen lamps, one plasma arc lamp, and one LED light curing unit were used. Intensity distribution of light emitted from the light guide tip was measured at 1.0-mm intervals across the guide tip. Distribution of Knoop hardness number on the surface of resin irradiated with the light curing units was also measured. For all units, inhomogeneous distribution of light intensity across the guide tip was observed. Minimum light intensity values were 19-80% of the maximum values. In terms of surface hardness, inhomogeneous distribution was also observed for the materials irradiated with the tested units. Minimum values were 53-92% of the maximum values. Our results indicated that markedly inhomogeneous light emitted from light curing unit could result in inhomogeneous polymerization in some areas of the restoration below the light guide tip.

On the minimum quantum requirement of photosynthesis.

PubMed

Zeinalov, Yuzeir

2009-01-01

An analysis of the shape of photosynthetic light curves is presented and the existence of the initial non-linear part is shown as a consequence of the operation of the non-cooperative (Kok's) mechanism of oxygen evolution or the effect of dark respiration. The effect of nonlinearity on the quantum efficiency (yield) and quantum requirement is reconsidered. The essential conclusions are: 1) The non-linearity of the light curves cannot be compensated using suspensions of algae or chloroplasts with high (>1.0) optical density or absorbance. 2) The values of the maxima of the quantum efficiency curves or the values of the minima of the quantum requirement curves cannot be used for estimation of the exact value of the maximum quantum efficiency and the minimum quantum requirement. The estimation of the maximum quantum efficiency or the minimum quantum requirement should be performed only after extrapolation of the linear part at higher light intensities of the quantum requirement curves to "0" light intensity.

29 CFR 1918.92 - Illumination.

Code of Federal Regulations, 2011 CFR

2011-07-01

... operations, illumination for cargo transfer operations shall be of a minimum light intensity of five foot-candles (54 lux). Where work tasks require more light to be performed safely, supplemental lighting shall... surface, in the plane in which the task/working surface is present. (c) Arrangement of lights. Lights...

14 CFR 29.1391 - Minimum intensities in the horizontal plane of forward and rear position lights.

Code of Federal Regulations, 2011 CFR

2011-01-01

...: Dihedral angle (light included) Angle from right or left of longitudinal axis, measured from dead ahead Intensity (candles) L and R (forward red and green) 0° to 10°10° to 20° 20° to 110° 4030 5 A (rear white...

14 CFR 23.1391 - Minimum intensities in the horizontal plane of position lights.

Code of Federal Regulations, 2012 CFR

2012-01-01

...: Dihedral angle (light included) Angle from right or left of longitudinal axis, measured from dead ahead Intensity (candles) L and R (red and green) 0° to 10°10° to 20° 20° to 110° 4030 5 A (rear white) 110° to...

14 CFR 29.1391 - Minimum intensities in the horizontal plane of forward and rear position lights.

Code of Federal Regulations, 2013 CFR

2013-01-01

...: Dihedral angle (light included) Angle from right or left of longitudinal axis, measured from dead ahead Intensity (candles) L and R (forward red and green) 0° to 10°10° to 20° 20° to 110° 4030 5 A (rear white...

14 CFR 27.1391 - Minimum intensities in the horizontal plane of forward and rear position lights.

Code of Federal Regulations, 2013 CFR

2013-01-01

...: Dihedral angle (light included) Angle from right or left of longitudinal axis, measured from dead ahead Intensity (candles) L and R (forward red and green) 10° to 10°10° to 20° 20° to 110° 4030 5 A (rear white...

14 CFR 25.1391 - Minimum intensities in the horizontal plane of forward and rear position lights.

Code of Federal Regulations, 2014 CFR

2014-01-01

...: Dihedral angle (light included) Angle from right or left of longitudinal axis, measured from dead ahead Intensity (candles) L and R (forward red and green) 0° to 10°10° to 20° 20° to 110° 4030 5 A (rear white...

14 CFR 23.1391 - Minimum intensities in the horizontal plane of position lights.

Code of Federal Regulations, 2013 CFR

2013-01-01

...: Dihedral angle (light included) Angle from right or left of longitudinal axis, measured from dead ahead Intensity (candles) L and R (red and green) 0° to 10°10° to 20° 20° to 110° 4030 5 A (rear white) 110° to...

14 CFR 25.1391 - Minimum intensities in the horizontal plane of forward and rear position lights.

Code of Federal Regulations, 2011 CFR

2011-01-01

...: Dihedral angle (light included) Angle from right or left of longitudinal axis, measured from dead ahead Intensity (candles) L and R (forward red and green) 0° to 10° 10° to 20° 20° to 110° 40 30 5 A (rear white...

14 CFR 29.1391 - Minimum intensities in the horizontal plane of forward and rear position lights.

Code of Federal Regulations, 2014 CFR

2014-01-01

...: Dihedral angle (light included) Angle from right or left of longitudinal axis, measured from dead ahead Intensity (candles) L and R (forward red and green) 0° to 10°10° to 20° 20° to 110° 4030 5 A (rear white...

14 CFR 27.1391 - Minimum intensities in the horizontal plane of forward and rear position lights.

Code of Federal Regulations, 2011 CFR

2011-01-01

...: Dihedral angle (light included) Angle from right or left of longitudinal axis, measured from dead ahead Intensity (candles) L and R (forward red and green) 10° to 10°10° to 20° 20° to 110° 4030 5 A (rear white...

14 CFR 25.1391 - Minimum intensities in the horizontal plane of forward and rear position lights.

Code of Federal Regulations, 2013 CFR

2013-01-01

...: Dihedral angle (light included) Angle from right or left of longitudinal axis, measured from dead ahead Intensity (candles) L and R (forward red and green) 0° to 10°10° to 20° 20° to 110° 4030 5 A (rear white...

14 CFR 27.1391 - Minimum intensities in the horizontal plane of forward and rear position lights.

Code of Federal Regulations, 2014 CFR

2014-01-01

...: Dihedral angle (light included) Angle from right or left of longitudinal axis, measured from dead ahead Intensity (candles) L and R (forward red and green) 10° to 10°10° to 20° 20° to 110° 4030 5 A (rear white...

14 CFR 23.1391 - Minimum intensities in the horizontal plane of position lights.

Code of Federal Regulations, 2014 CFR

2014-01-01

...: Dihedral angle (light included) Angle from right or left of longitudinal axis, measured from dead ahead Intensity (candles) L and R (red and green) 0° to 10°10° to 20° 20° to 110° 4030 5 A (rear white) 110° to...

14 CFR 27.1391 - Minimum intensities in the horizontal plane of forward and rear position lights.

Code of Federal Regulations, 2012 CFR

2012-01-01

...: Dihedral angle (light included) Angle from right or left of longitudinal axis, measured from dead ahead Intensity (candles) L and R (forward red and green) 10° to 10°10° to 20° 20° to 110° 4030 5 A (rear white...

14 CFR 25.1391 - Minimum intensities in the horizontal plane of forward and rear position lights.

Code of Federal Regulations, 2012 CFR

2012-01-01

...: Dihedral angle (light included) Angle from right or left of longitudinal axis, measured from dead ahead Intensity (candles) L and R (forward red and green) 0° to 10° 10° to 20° 20° to 110° 40 30 5 A (rear white...

14 CFR 29.1391 - Minimum intensities in the horizontal plane of forward and rear position lights.

Code of Federal Regulations, 2012 CFR

2012-01-01

...: Dihedral angle (light included) Angle from right or left of longitudinal axis, measured from dead ahead Intensity (candles) L and R (forward red and green) 0° to 10°10° to 20° 20° to 110° 4030 5 A (rear white...

14 CFR 23.1391 - Minimum intensities in the horizontal plane of position lights.

Code of Federal Regulations, 2011 CFR

2011-01-01

...: Dihedral angle (light included) Angle from right or left of longitudinal axis, measured from dead ahead Intensity (candles) L and R (red and green) 0° to 10°10° to 20° 20° to 110° 4030 5 A (rear white) 110° to...

Three-dimensional motion detection of a 20-nm gold nanoparticle using twilight-field digital holography with coherence regulation.

PubMed

Goto, Kazufumi; Hayasaki, Yoshio

2015-07-15

In the twilight-field method for obtaining interference fringes with high contrast in in-line digital holography, only the intensity of the reference light is regulated to be close to the intensity of the object light, which is the ultra-weak scattered light from a nanoparticle, by using a low-frequency attenuation filter. Coherence of the light also strongly affects the contrast of the interference fringes. High coherence causes a lot of undesired coherent noise, which masks the fringes derived from the nanoparticles. Too-low coherence results in fringes with low contrast and a correspondingly low signal-to-noise ratio. Consequently, proper regulation of the coherence of the light source, in this study the spectral width, improves the minimum detectable size in holographic three-dimensional position measurement of nanoparticles. By using these methods, we were able to measure the position of a gold nanoparticle with a minimum diameter of 20 nm.

OSO 8 observations of wave propagation in the solar chromosphere and transition region

NASA Technical Reports Server (NTRS)

Chipman, E. G.

1978-01-01

The University of Colorado instrument on OSO 8 has been used to observe relative phases of the 300-s intensity variation between the temperature-minimum region and several emission lines formed in the solar chromosphere and chromosphere-corona transition region. The lines used are due to Fe II, Si II, C II, Si IV, and C IV. The scattered light in the spectrograph, which originates almost entirely in the spectral region between 1700 and 1900 A, was used as a probe of the temperature-minimum region. The lines of Fe II, Si II, and C II show almost identical delays of approximately 30 s relative to the temperature minimum, while the intensity oscillations of the lines of Si IV and C IV appear to lead the temperature-minimum intensity oscillations by about 10 s.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kunder, Andrea; Chaboyer, Brian; Layden, Andrew

New R-band observations of 21 local field RR Lyrae variable stars are used to explore the reliability of minimum light (V - R) colors as a tool for measuring interstellar reddening. For each star, R-band intensity mean magnitudes and light amplitudes are presented. Corresponding V-band light curves from the literature are supplemented with the new photometry, and (V - R) colors at minimum light are determined for a subset of these stars as well as for other stars in the literature. Two different definitions of minimum light color are examined, one which uses a Fourier decomposition to the V andmore » R light curves to find (V - R) at minimum V-band light, (V - R) {sup F} {sub min}, and the other which uses the average color between the phase interval 0.5-0.8, (V - R){sup {phi}}{sup (0.5-0.8)} {sub min}. From 31 stars with a wide range of metallicities and pulsation periods, the mean dereddened RR Lyrae color at minimum light is (V - R) {sup F} {sub min,0} = 0.28 {+-} 0.02 mag and (V - R){sup {phi}}{sup (0.5-0.8)} {sub min,0} = 0.27 {+-} 0.02 mag. As was found by Guldenschuh et al. using (V - I) colors, any dependence of the star's minimum light color on metallicity or pulsation amplitude is too weak to be formally detected. We find that the intrinsic (V - R) of Galactic bulge RR Lyrae stars are similar to those found by their local counterparts and hence that bulge RR0 Lyrae stars do not have anomalous colors as compared to the local RR Lyrae stars.« less

[Habitat suitability index model and minimum habitat area estimation of young Procypris rabaudi (Tchang): a simulation experiment in laboratory].

PubMed

Feng, Xian-Bin; Zhu, Yong-Jiu; Li, Xi; He, Yong-Feng; Zhao, Jian-Hua; Yang, De-Guo

2013-01-01

Under the conditions of simulated micro-habitat in laboratory, and by using experimental ecological methods, this paper evaluated the suitability index (HSI) of young Procypris rabaudi for habitat factors (substrate, light intensity and water depth). The habitat suitability models of the young P. rabaudi were established, and the minimum habitat area of the young P. rabaudi was estimated. The young P. rabaudi preferred the habitats with the gravel diameter from 10 to 15 cm, light intensity from 0.2 to 1.8 lx, and water depth from 0 to 15 cm (distance from the bottom of the tank). The three suitability index models of the substrate, light intensity and water depth for the young P. rabaudi were SI(s) = 1.7338e(-0.997x)(SI(S) is the suitability index of substrate, and x is the gravel diameter; R2 = 0.89, P < 0.01), SI(L) = 3.0121e(-1.339x)(SI(L) is the suitability index of light intensity, and x is the light intensity; R2 = 0.93, P < 0.01), and SI(W) = 2.4055e(-1.245x)(SI(W) is the suitability index of water depth, and x is the water depth; R2 = 0.97, P < 0.01), respectively. Arithmetic mean model HSI = (SI(S)+SI(L)+SI(W))/3 was most available for the estimation of the habitat suitability of young P. rabaudi. A total of seven groups of young P. rabaudi which established and maintained a relatively stable habitat area range were found. This habitat area ranged from 628 to 2015 cm2, with an average of 1114 cm2.

[Effects of light intensity on Quercus liaotungensis seed germination and seedling growth].

PubMed

Yan, Xing-fu; Wang, Jian-li; Zhou, Li-biao

2011-07-01

This paper studied the effects of different shading (55.4%, 18.9%, 5.5%, 2.2%, 0.5% , and 0.3% natural sunlight) on the seed germination and seedling growth of Quercus liaotungensis. The seed germination rate and germination index were the highest (72.5% and 0.22, respectively) at 55.4% natural sunlight, declined with decreasing light intensity, and were the lowest (42.5% and 0.11, respectively) at 0.3% natural sunlight. Strong light had definite delaying effect on the germination. The index of germination vigor increased with decreasing light intensity, being the maximum at 0.5% natural sunlight. The delay of seed germination under strong light could be the selective tradeoff on varied seed fates. Strong light benefited the basal stem diameter and root system growth and dry mass accumulation of Q. liaotunensis seedling, but resulted in the minimum seedlings height (6.06 cm). Greater morphological plasticity was observed for the seedlings under different shading, which lent support to the higher adaptability of the seedlings to light environment. For example, the specific leaf area, specific shoot length, specific root length, and chlorophyll b and total chlorophyll contents were the maximum at 0.5% natural sunlight, being 142.57 cm2 x g(-1), 156.86 cm x g(-1), 271.87 cm x g(-1), 0.07 g x cm(-2), and 0.24 g x cm(-2), respectively, and the minimum at 55.4% natural sunlight, being 44.89 cm2 x g(-1), 52.84 cm x g(-1), 101.98 cm x g(-1), 0.04 g x cm(-2), and 0.15 g x cm(-2), respectively. The variation of the root/shoot ratio of Q. liaotungensis seedlings under different shading could be the effects of the combination of light intensity and water availability.

Nonuniform distribution of phase noise in distributed acoustic sensing based on phase-sensitive OTDR

NASA Astrophysics Data System (ADS)

Yu, Zhijie; Lu, Yang; Meng, Zhou

2017-10-01

A phase-sensitive optical time-domain reflectometry (∅-OTDR) implements distributed acoustic sensing (DAS) due to its ability for high sensitivity vibration measurement. Phase information of acoustic vibration events can be acquired by interrogation of the vibration-induced phase change between coherent Rayleigh scattering light from two points of the sensing fiber. And DAS can be realized when applying phase generated carrier (PGC) algorithm to the whole sensing fiber while the sensing fiber is transformed into a series of virtual sensing channels. Minimum detectable vibration of a ∅-OTDR is limited by phase noise level. In this paper, nonuniform distribution of phase noise of virtual sensing channels in a ∅-OTDR is investigated theoretically and experimentally. Correspondence between the intensity of Rayleigh scattering light and interference fading as well as polarization fading is analyzed considering inner interference of coherent Rayleigh light scattered from a multitude of scatters within pulse duration, and intensity noise related to the intensity of Rayleigh scattering light can be converted to phase noise while measuring vibration-induced phase change. Experiments are performed and the results confirm the predictions of the theoretical analysis. This study is essential for acquiring insight into nonuniformity of phase noise in DAS based on a ∅-OTDR, and would put forward some feasible methods to eliminate the effect of interference fading and polarization fading and optimize the minimum detectable vibration of a ∅-OTDR.

Single-beam, dark toroidal optical traps for cold atoms

NASA Astrophysics Data System (ADS)

Fatemi, Fredrik K.; Olson, Spencer E.; Bashkansky, Mark; Dutton, Zachary; Terraciano, Matthew

2007-02-01

We demonstrate the generation of single-beam dark toroidal optical intensity distributions, which are of interest for neutral atom storage and atom interferometry. We demonstrate experimentally and numerically optical potentials that contain a ring-shaped intensity minimum, bounded in all directions by higher intensity. We use a spatial light modulator to alter the phase of an incident laser beam, and analyze the resulting optical propagation characteristics. For small toroidal traps (< 50 μm diameter), we find an optimal superposition of Laguerre-Gaussian modes that allows the formation of single-beam toroidal traps. We generate larger toroidal bottle traps by focusing hollow beams with toroidal lenses imprinted onto the spatial light modulator.

Reduction of temperature rise in high-speed photography

NASA Technical Reports Server (NTRS)

Slater, Howard A.

1987-01-01

Information is provided on filtration with glass and infrared absorbing and reflecting filters. Glass and infrared filtration is a simple and effective method to reduce the radiation heat transfer associated with continuous high intensity tungsten lamps. The results of a filtration experiment are explained. The figures provide starting points for quantifying the effectiveness of various filters and associated light intensities. The combination of a spectrally selective reflector (hot or cold mirror) based on multilayer thin film principles and heat absorbing or infrared opaque glass results in the maximum reduction in temperature rise with a minimum of incident light loss. Use is recommended of a voltage regulator to further control temperature rise and incident light values.

Reduction of temperature rise in high-speed photography

NASA Technical Reports Server (NTRS)

Slater, Howard A.

1988-01-01

Information is provided on filtration with glass and infrared absorbing and reflecting filters. Glass and infrared filtration is a simple and effective method to reduce the radiation heat transfer associated with continuous high intensity tungsten lamps. The results of a filtration experiment are explained. The figures provide starting points for quantifying the effectiveness of various filters and associated light intensities. The combination of a spectrally selective reflector (hot or cold mirror) based on multilayer thin film principles and heat absorbing or infrared opaque glass results in the maximum reduction in temperature rise with a minimum of incident light loss. Use is recommended of a voltage regulator to further control temperature rise and incident light values.

Assessment of the Effects of Light Availability on Growth and Competition Between Strains of Planktothrix agardhii and Microcystis aeruginosa.

PubMed

Torres, Camila de Araujo; Lürling, Miquel; Marinho, Marcelo Manzi

2016-05-01

In this study, we tested the hypothesis that Planktothrix agardhii strains isolated from a tropical water body were better competitors for light than Microcystis aeruginosa strains. These cyanobacteria are common in eutrophic systems, where light is one of the main drivers of phytoplankton, and Planktothrix is considered more shade-adapted and Microcystis more high-light tolerant. First, the effect of light intensities on growth was studied in batch cultures. Next, the minimum requirement of light (I*) and the effect of light limitation on the outcome of competition was investigated in chemostats. All strains showed similar growth at 10 μmol photons m(-2) s(-1), demonstrating the ability of the two species to grow in low light. The optimum light intensity was lower for P. agardhii, but at the highest light intensity, Microcystis strains reached higher biovolume, confirming that P. agardhii has higher sensitivity to high light. Nonetheless, P. agardhii grew in light intensities considered high (500 μmol photons m(-2) s(-1)) for this species. M. aeruginosa showed a higher carrying capacity in light-limited condition, but I* was similar between all the strains. Under light competition, Microcystis strains displaced P. agardhii and dominated. In two cases, there was competitive exclusion and in the other two P. agardhii managed to remain in the system with a low biovolume (≈15%). Our findings not only show that strains of P. agardhii can grow under higher light intensities than generally assumed but also that strains of M. aeruginosa are better competitors for light than supposed. These results help to understand the co-occurrence of these species in tropical environments and the dominance of M. aeruginosa even in low-light conditions.

PHOTOTROPISM OF GERMINATING MYCELIA OF SOME PARASITIC FUNGI

DTIC Science & Technology

uredinales on young wheat plants; Distribution and significance of the phototropism of germinating mycelia -- confirmation of older data, examination of...eight additional uredinales, probable meaning of negative phototropism for the occurrence of infection; Analysis of the stimulus physiology of the...reaction -- the minimum effective illumination intensity, the effective special region, inversion of the phototropic reaction in liquid paraffin, the negative light- growth reaction, the light-sensitive zone.

A Study of Light Level Effect on the Accuracy of Image Processing-based Tomato Grading

NASA Astrophysics Data System (ADS)

Prijatna, D.; Muhaemin, M.; Wulandari, R. P.; Herwanto, T.; Saukat, M.; Sugandi, W. K.

2018-05-01

Image processing method has been used in non-destructive tests of agricultural products. Compared to manual method, image processing method may produce more objective and consistent results. Image capturing box installed in currently used tomato grading machine (TEP-4) is equipped with four fluorescence lamps to illuminate the processed tomatoes. Since the performance of any lamp will decrease if its service time has exceeded its lifetime, it is predicted that this will affect tomato classification. The objective of this study was to determine the minimum light levels which affect classification accuracy. This study was conducted by varying light level from minimum and maximum on tomatoes in image capturing boxes and then investigates its effects on image characteristics. Research results showed that light intensity affects two variables which are important for classification, for example, area and color of captured image. Image processing program was able to determine correctly the weight and classification of tomatoes when light level was 30 lx to 140 lx.

The 3.5 micron light curves of long period variable stars. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Strecker, D. W.

1973-01-01

Infrared observations at an effective wavelength of 3.5 microns of a selected group of long period variable (LPV) stars are presented. Mira type and semiregular stars of M, S, and C spectral classifications were monitored throughout the full cycle of variability. Although the variable infrared radiation does not exactly repeat in intensity or time, the regularity is sufficient to produce mean 3.5 micron light curves. The 3.5 micron maximum radiation lags the visual maximum by about one-seventh of a cycle, while the minimum 3.5 micron intensity occurs nearly one-half cycle after infrared maximum. In some stars, there are inflections or humps on the ascending portion of the 3.5 micron light curve which may also be seen in the visual variations.

Effect of light intensity on ovarian gene expression, reproductive performance and body weight of rabbit does.

PubMed

Sun, Liangzhan; Wu, Zhenyu; Li, Fuchang; Liu, Lei; Li, Jinglin; Zhang, Di; Sun, Chaoran

2017-08-01

The objective of the experiment was to find the minimum light intensity which could improve reproduction by examining its effect on ovarian gene expression, reproductive performance and body weight of rabbit does with three different light intensities: 60 (L), 80 (M), and 100 (H)lx. A total of 144 Rex-rabbits submitted to a 49-day reproductive regimen were used in this study. Ovaries were collected and relative abundance of mRNA for ovarian proteins of interest was examined with real-time PCR. Amount of protein for proteins of interest was examined by immunohistochemistry. Reproductive performance and doe bodyweight of the first three consecutive reproductive periods after initiation of the light intensity treatments were evaluated. The results provided evidence that light intensity had no effect on relative abundance of estradiol receptor-α (ER-α), follicle stimulating hormone receptor (FSHR), luteinizing hormone receptor (LHR), gonadotropin releasing hormone receptor 1 (GnRHR1) and progesterone receptor (PGR) mRNA. The relative abundance of growth hormone receptor (GHR) mRNA was, however, greater in Group L than M and H (P<0.05). No difference was observed for all reproductive indices as a result of submission to the three light intensities (P>0.05). The bodyweight of the does in Group L was greater than the other two groups at first insemination, second insemination and the second postpartum period (P<0.05). There was no difference in bodyweight after the second postpartum period (P>0.05). These observations suggest that light intensity between 60 and 100lx has no effect on the reproductive performance of rabbit does, however, the amounts of GHR mRNA and growth hormone (GH) protein were affected and the greater light intensity had a negative effect on bodyweight between the time of the first insemination and the second partum period. Copyright © 2017 Elsevier B.V. All rights reserved.

50 CFR 665.815 - Pelagic longline seabird mitigation measures.

Code of Federal Regulations, 2014 CFR

2014-10-01

... rate; (vi) Use completely thawed bait that has been dyed blue to an intensity level specified by a... 1 lb size) containing blue dye on board the vessel; and (viii) Follow the requirements in paragraphs... complete the deployment no later than local sunrise, using only the minimum vessel lights to conform with...

50 CFR 665.815 - Pelagic longline seabird mitigation measures.

Code of Federal Regulations, 2013 CFR

2013-10-01

... rate; (vi) Use completely thawed bait that has been dyed blue to an intensity level specified by a... 1 lb size) containing blue dye on board the vessel; and (viii) Follow the requirements in paragraphs... complete the deployment no later than local sunrise, using only the minimum vessel lights to conform with...

50 CFR 665.815 - Pelagic longline seabird mitigation measures.

Code of Federal Regulations, 2011 CFR

2011-10-01

... rate; (vi) Use completely thawed bait that has been dyed blue to an intensity level specified by a... 1 lb size) containing blue dye on board the vessel; and (viii) Follow the requirements in paragraphs... complete the deployment no later than local sunrise, using only the minimum vessel lights to conform with...

50 CFR 665.815 - Pelagic longline seabird mitigation measures.

Code of Federal Regulations, 2012 CFR

2012-10-01

... rate; (vi) Use completely thawed bait that has been dyed blue to an intensity level specified by a... 1 lb size) containing blue dye on board the vessel; and (viii) Follow the requirements in paragraphs... complete the deployment no later than local sunrise, using only the minimum vessel lights to conform with...

Minimum light duration needed to maintain winter and summer adapted eelgrass (Zostera marina) as determined by mesocosm experiments

EPA Science Inventory

The intensity and duration of photosynthetically active radiation (PAR) is one of the primary factors determining seagrass survival. A commonly used metric to evaluate if there is sufficient PAR is Hsat, which is the number of hours per day in which photosynthetic pigments are s...

Behavioral and physiological photoresponses to light intensity by intertidal microphytobenthos

NASA Astrophysics Data System (ADS)

Du, Guoying; Yan, Hongmei; Liu, Chunrong; Mao, Yunxiang

2018-03-01

Behavioral and physiological responses to light are the two major mechanisms by which natural microphytobenthic assemblages adapt to the intertidal environment and protect themselves from light stress. The present study investigated these photoresponses with different light intensities over 8 h of illumination, and used a specific inhibitor (Latrunculin A, Lat A) for migration to compare migratory and non-migratory microphytobenthos (MPB). Photosynthetic activity was detected using rapid light curves and induction curves by chlorophyll fluorescence. It showed distinct variation in migratory responses to different light intensities; high light induced downward migration to avoid photoinhibition, and low and medium light (50-250 μmol/(m2·s)) promoted upward migration followed by downward migration after certain period of light exposure. No significant difference in non-photochemical quenching (NPQ) or PSII maximal quantum yield ( F v/ F m) was detected between low and medium light irradiance, possibly indicating that only high light influences the photosynthetic capability of MPB. Decreased photosynthetic activity, indicated by three parameters, the maximum relative electron transport rate (rETR max), minimum saturating irradiance ( E k) and light utilization coefficient ( α), was observed in MPB after exposure to prolonged illumination under low and medium light. Lat A effectively inhibited the migration of MPB in all light treatments and induced lower F v/ F m under high light (500 and 100 μmol/(m2·s)) and prolonged illumination at 250 μmol/(m2·s), but did not significantly influence F v/ F m under low light (0-100 μmol/(m2·s)) or NPQ. The increase of NPQ in Lat A treatments with time implied that the MPB assemblages can recover their physiological photoprotection capacity to adapt to light stress. Non-migratory MPB exhibited lower light use efficiency (lower α) and lower maximum photosynthetic capacity (lower rETR max) than migratory MPB under light intensities above 250 μmol/(m2·s) after 4.0 h illumination.

A measurement of the holographic minimum-observable beam branching ratio in the FERMILAB 15-ft bubble chamber

NASA Astrophysics Data System (ADS)

Aderholz, M.; Aggarwal, M. M.; Akbari, H.; Allport, P. P.; Badyal, S. K.; Ballagh, H. C.; Barth, M.; Baton, J. P.; Bingham, H. H.; Bjelkhagen, H.; Brucker, E. B.; Burnstein, R. A.; Campbell, J. R.; Cence, R. J.; Chatterjee, T. K.; Clayton, E. F.; Corrigan, G.; Coutures, C.; DeProspo, D.; Devanand; De Wolf, E. A.; Faulkner, P. J. W.; Foeth, H.; Fretter, W. B.; Geissler, K.; Gupta, V. K.; Hanlon, J.; Harigel, G. G.; Harris, F. A.; Hawkins, J.; Jabiol, M. A.; Jacques, P.; Jones, G. T.; Jones, M. D.; Kafka, T.; Kalelkar, M.; Kasper, P.; Kohli, J. M.; Koller, E. L.; Krawiec, R. J.; Lauko, M.; Lys, J. E.; Marage, P.; Milburn, R. H.; Miller, D. B.; Mittra, I. S.; Mobayyen, M. M.; Moreels, J.; Morrison, D. R. O.; Myatt, G.; Naon, R.; Napier, A.; Naylor, P.; Neveu, M.; Passmore, D.; Peters, M. W.; Peterson, V. Z.; Plano, R.; Rao, N. K.; Rubin, H. A.; Sacton, J.; Sambyal, S. S.; Schmitz, N.; Schneps, J.; Sekulin, R. L.; Sewell, S.; Singh, J. B.; Smart, W.; Stamer, P.; Varvell, K. E.; Verluyten, L.; Voyvodic, L.; Wachsmuth, H.; Wainstein, S.; Williams, W.; Willocq, S.; Yost, G. P.; E-632 Collaboration

1999-01-01

Holography has been used successfully in combination with conventional optics for the first time in a large cryogenic bubble chamber, the 15-foot bubble chamber at Fermilab, during a physics run. The innovative system combined the reference beam with the object beam, irradiating a conical volume of ˜1.4 m 3. Bubble tracks from neutrino interactions with a width of ˜120 μm have been recorded with good contrast. The ratio of intensities of the object light to the reference light striking the film is called the beam branching ratio. We obtained in our experiment an exceedingly small minimum-observable ratio of (0.54±0.21)×10 -7. The technology has the potential for a wide range of applications.

[System design of open-path natural gas leakage detection based on Fresnel lens].

PubMed

Xia, Hui; Liu, Wen-Qing; Zhang, Yu-Jun; Kan, Rui-Feng; Cui, Yi-Ben; Wang, Min; He, Ying; Cui, Xiao-Juan; Ruan, Jun; Geng, Hui

2009-03-01

Based on the technology of tunable diode laser absorption spectroscopy (TDLAS) in conjunction with second harmonic wave detection, a long open-path TDLAS system using a 1.65 microm InGaAsP distributed feedback laser was developed, which is used for detecting pipeline leakage. In this system, a high cost performance Fresnel lens is used as the receiving optical system, which receives the laser-beam reflected by a solid corner cube reflector, and focuses the receiving laser-beam to the InGaAs detector. At the same time, the influences of the concentration to the fluctuation of light intensity were taken into account in the process of measurement, and were eliminated by the method of normalized light intensity. As a result, the measurement error caused by the fluctuation of light intensity was made less than 1%. The experiment of natural gas leakage detection was simulated, and the detection sensitivity is 0.1 x 10(-6) (ratio by volume) with a total path of 320 m. According to the receiving light efficiency of the optical system and the detectable minimum light intensity of the detector, the detectable maximal optical path of the system was counted to be 2 000 m. The results of experiment show that it is a feasible design to use the Fresnel lens as the receiving optical system and can satisfy the demand of the leakage detection of natural gas.

Light-induced flickering of DsRed provides evidence for distinct and interconvertible fluorescent states.

PubMed Central

Malvezzi-Campeggi, F; Jahnz, M; Heinze, K G; Dittrich, P; Schwille, P

2001-01-01

Green fluorescent protein (GFP) from jellyfish Aequorea victoria, the powerful genetically encoded tag presently available in a variety of mutants featuring blue to yellow emission, has found a red-emitting counterpart. The recently cloned red fluorescent protein DsRed, isolated from Discosoma corals (), with its emission maximum at 583 nm, appears to be the long awaited tool for multi-color applications in fluorescence-based biological research. Studying the emission dynamics of DsRed by fluorescence correlation spectroscopy (FCS), it can be verified that this protein exhibits strong light-dependent flickering similar to what is observed in several yellow-shifted mutants of GFP. FCS data recorded at different intensities and excitation wavelengths suggest that DsRed appears under equilibrated conditions in at minimum three interconvertible states, apparently fluorescent with different excitation and emission properties. Light absorption induces transitions and/or cycling between these states on time scales of several tens to several hundreds of microseconds, dependent on excitation intensity. With increasing intensity, the emission maximum of the static fluorescence continuously shifts to the red, implying that at least one state emitting at longer wavelength is preferably populated at higher light levels. In close resemblance to GFP, this light-induced dynamic behavior implies that the chromophore is subject to conformational rearrangements upon population of the excited state. PMID:11509387

A Measurement of the holographic minimum observable beam branching ratio in the Fermilab 15-foot bubble chamber

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aderholz, M.; Aggarwal, M.M.; Akbari, H.

1997-01-01

Holography has been used successfully in combination with conventional optics for the first time in a large cryogenic bubble chamber, the 15-Foot Bubble Chamber at Fermilab, during a physics run. The innovative system combined the reference beam with the object beam, illuminating a conical volume of {approx} 1.4 m{sup 3}. Bubble tracks from neutrino interactions with a width of {approx} 120 {micro}m have been recorded with good contrast. The ratio of intensities of the object light to the reference light striking the film is called the Beam Branching Ratio. We obtained in our experiment an exceedingly small minimum-observable ratio ofmore » (0.54 {+-} 0.21) x 10{sup -7}. The technology has the potential for a wide range of applications.« less

Evaluation of automated threshold selection methods for accurately sizing microscopic fluorescent cells by image analysis.

PubMed Central

Sieracki, M E; Reichenbach, S E; Webb, K L

1989-01-01

The accurate measurement of bacterial and protistan cell biomass is necessary for understanding their population and trophic dynamics in nature. Direct measurement of fluorescently stained cells is often the method of choice. The tedium of making such measurements visually on the large numbers of cells required has prompted the use of automatic image analysis for this purpose. Accurate measurements by image analysis require an accurate, reliable method of segmenting the image, that is, distinguishing the brightly fluorescing cells from a dark background. This is commonly done by visually choosing a threshold intensity value which most closely coincides with the outline of the cells as perceived by the operator. Ideally, an automated method based on the cell image characteristics should be used. Since the optical nature of edges in images of light-emitting, microscopic fluorescent objects is different from that of images generated by transmitted or reflected light, it seemed that automatic segmentation of such images may require special considerations. We tested nine automated threshold selection methods using standard fluorescent microspheres ranging in size and fluorescence intensity and fluorochrome-stained samples of cells from cultures of cyanobacteria, flagellates, and ciliates. The methods included several variations based on the maximum intensity gradient of the sphere profile (first derivative), the minimum in the second derivative of the sphere profile, the minimum of the image histogram, and the midpoint intensity. Our results indicated that thresholds determined visually and by first-derivative methods tended to overestimate the threshold, causing an underestimation of microsphere size. The method based on the minimum of the second derivative of the profile yielded the most accurate area estimates for spheres of different sizes and brightnesses and for four of the five cell types tested. A simple model of the optical properties of fluorescing objects and the video acquisition system is described which explains how the second derivative best approximates the position of the edge. Images PMID:2516431

Particle size analysis in a turbid media with a single-fiber, optical probe while using a visible spectrometer

DOEpatents

Canpolat, Murat; Mourant, Judith R.

2003-12-09

Apparatus and method for measuring scatterer size in a dense media with only a single fiber for both light delivery and collection are disclosed. White light is used as a source and oscillations of the detected light intensities are measured as a function of wavelength. The maximum and minimum of the oscillations can be used to determine scatterer size for monodisperse distributions of spheres when the refractive indices are known. In addition several properties of the probe relevant to tissue diagnosis are disclosed including the effects of absorption, a broad distribution of scatterers, and the depth probed.

Single-mode VCSEL operation via photocurrent feedback

NASA Astrophysics Data System (ADS)

Riyopoulos, Spilios

1999-04-01

On-axis channeling through the use of photoactive layers in VCSEL cavities is proposed to counteract hole burning and mode switching. The photoactive layers act as variable resistivity screens whose radial `aperture' is controlled by the light itself. It is numerically demonstrated that absorption of a small fraction of the light intensity suffices for significant on axis current peaking and single mode operation at currents many times threshold, with minimum efficiency loss and optical mode distortion. Fabrication is implemented during the molecular beam epitaxy phase without wafer post processing, as for oxide apertures.

Polarimetric imaging of retinal disease by polarization sensitive SLO

NASA Astrophysics Data System (ADS)

Miura, Masahiro; Elsner, Ann E.; Iwasaki, Takuya; Goto, Hiroshi

2015-03-01

Polarimetry imaging is used to evaluate different features of the macular disease. Polarimetry images were recorded using a commercially- available polarization-sensitive scanning laser opthalmoscope at 780 nm (PS-SLO, GDx-N). From data sets of PS-SLO, we computed average reflectance image, depolarized light images, and ratio-depolarized light images. The average reflectance image is the grand mean of all input polarization states. The depolarized light image is the minimum of crossed channel. The ratio-depolarized light image is a ratio between the average reflectance image and depolarized light image, and was used to compensate for variation of brightness. Each polarimetry image is compared with the autofluorescence image at 800 nm (NIR-AF) and autofluorescence image at 500 nm (SW-AF). We evaluated four eyes with geographic atrophy in age related macular degeneration, one eye with retinal pigment epithelium hyperplasia, and two eyes with chronic central serous chorioretinopathy. Polarization analysis could selectively emphasize different features of the retina. Findings in ratio depolarized light image had similarities and differences with NIR-AF images. Area of hyper-AF in NIR-AF images showed high intensity areas in the ratio depolarized light image, representing melanin accumulation. Areas of hypo-AF in NIR-AF images showed low intensity areas in the ratio depolarized light images, representing melanin loss. Drusen were high-intensity areas in the ratio depolarized light image, but NIR-AF images was insensitive to the presence of drusen. Unlike NIR-AF images, SW-AF images showed completely different features from the ratio depolarized images. Polarization sensitive imaging is an effective tool as a non-invasive assessment of macular disease.

Use of a supercontinuum white light in evaluating the spectral sensitivity of the pupil light reflex

NASA Astrophysics Data System (ADS)

Chin, Catherine; Leick, Lasse; Podoleanu, Adrian; Lall, Gurprit S.

2018-03-01

We assessed the spectral sensitivity of the pupillary light reflex in mice using a high power super continuum white light (SCWL) source in a dual wavelength configuration. This novel approach was compared to data collected from a more traditional setup using a Xenon arc lamp fitted with monochromatic interference filters. Irradiance response curves were constructed using both systems, with the added benefit of a two-wavelength, equivocal power, output using the SCWL. The variables applied to the light source were intensity, wavelength and stimulus duration through which the physiological output measured was the minimum pupil size attained under such conditions. We show that by implementing the SCWL as our novel stimulus we were able to dramatically increase the physiological usefulness of our pupillometry system.

Photosystem II Photochemistry and Phycobiliprotein of the Red Algae Kappaphycus alvarezii and Their Implications for Light Adaptation

PubMed Central

Wang, Jinfeng; Zhu, Jianyi; Yao, Chunyan; Liu, Jianguo; Qin, Song; Jiang, Peng

2013-01-01

Photosystem II photochemistry and phycobiliprotein (PBP) genes of red algae Kappaphycus alvarezii, raw material of κ-carrageenan used in food and pharmaceutical industries, were analyzed in this study. Minimum saturating irradiance (I k) of this algal species was less than 115 μmol m−2 s−1. Its actual PSII efficiency (yield II) increased when light intensity enhanced and decreased when light intensity reached 200 μmol m−2 s−1. Under dim light, yield II declined at first and then increased on the fourth day. Under high light, yield II retained a stable value. These results indicate that K. alvarezii is a low-light-adapted species but possesses regulative mechanisms in response to both excessive and deficient light. Based on the PBP gene sequences, K. alvarezii, together with other red algae, assembled faster and showed a closer relationship with LL-Prochlorococcus compared to HL-Prochlorococcus. Many amino acid loci in PBP sequences of K. alvarezii were conserved with those of LL-Prochlorococcus. However, loci conserved with HL-Prochlorococcus but divergent with LL-Prochlorococcus were also found. The diversities of PE and PC are proposed to have played some roles during the algal evolution and divergence of light adaption. PMID:24380080

Photosystem II photochemistry and phycobiliprotein of the red algae Kappaphycus alvarezii and their implications for light adaptation.

PubMed

Guan, Xiangyu; Wang, Jinfeng; Zhu, Jianyi; Yao, Chunyan; Liu, Jianguo; Qin, Song; Jiang, Peng

2013-01-01

Photosystem II photochemistry and phycobiliprotein (PBP) genes of red algae Kappaphycus alvarezii, raw material of κ -carrageenan used in food and pharmaceutical industries, were analyzed in this study. Minimum saturating irradiance (I k) of this algal species was less than 115 μmol m(-2) s(-1). Its actual PSII efficiency (yield II) increased when light intensity enhanced and decreased when light intensity reached 200 μmol m(-2) s(-1). Under dim light, yield II declined at first and then increased on the fourth day. Under high light, yield II retained a stable value. These results indicate that K. alvarezii is a low-light-adapted species but possesses regulative mechanisms in response to both excessive and deficient light. Based on the PBP gene sequences, K. alvarezii, together with other red algae, assembled faster and showed a closer relationship with LL-Prochlorococcus compared to HL-Prochlorococcus. Many amino acid loci in PBP sequences of K. alvarezii were conserved with those of LL-Prochlorococcus. However, loci conserved with HL-Prochlorococcus but divergent with LL-Prochlorococcus were also found. The diversities of PE and PC are proposed to have played some roles during the algal evolution and divergence of light adaption.

Dynamic Control of Adsorption Sensitivity for Photo-EMF-Based Ammonia Gas Sensors Using a Wireless Network

PubMed Central

Vashpanov, Yuriy; Choo, Hyunseung; Kim, Dongsoo Stephen

2011-01-01

This paper proposes an adsorption sensitivity control method that uses a wireless network and illumination light intensity in a photo-electromagnetic field (EMF)-based gas sensor for measurements in real time of a wide range of ammonia concentrations. The minimum measurement error for a range of ammonia concentration from 3 to 800 ppm occurs when the gas concentration magnitude corresponds with the optimal intensity of the illumination light. A simulation with LabView-engineered modules for automatic control of a new intelligent computer system was conducted to improve measurement precision over a wide range of gas concentrations. This gas sensor computer system with wireless network technology could be useful in the chemical industry for automatic detection and measurement of hazardous ammonia gas levels in real time. PMID:22346680

Entrainment of oviposition in the fowl using bright and dim light cycles.

PubMed

Morris, T R; Bhatti, B M

1978-05-01

1. Nine short trial, involving 96 different treatments, were used to investigate the critical intensities and duration of bright and dim periods of lighting needed to entrain oviposition in cycles ranging from 21 to 30 h. 2. Entrainment was shown to depend upon the contrast between bright and dim lighting, and to be independent of the absolute light intensity. 3. A bright: dim ratio of 13:1 fully entrained oviposition in cycles of 25 h and 27 h. For 23-h and 28-h cycles a 30:1 ratio was required. Twenty-one-hour cycles required a ratio of 300:1 and with 30-h cycles a ratio of 1000:1 was needed to achieve full entrainment of oviposition. 4. In 24-h cycles, 1 h of bright lighting at 02.00 h was sufficient to override other environmental signals and cause eggs to be laid in the late evening, but a minimum bright period of 6 h was needed to cause full phase setting with 21-h cycles. 5. Circadian periodicity can easily be imposed on hens by providing a short exposure to bright light with a background of continuous dim light; but the signal must be increased (by providing a greater contrast between bright and dim lights and/or a longer period of bright lighting) to entrain oviposition when the cycle deviates markedly from the natural period of 24 h.

The wind-wind collision hole in eta Car

NASA Astrophysics Data System (ADS)

Damineli, A.; Teodoro, M.; Richardson, N. D.; Gull, T. R.; Corcoran, M. F.; Hamaguchi, K.; Groh, J. H.; Weigelt, G.; Hillier, D. J.; Russell, C.; Moffat, A.; Pollard, K. R.; Madura, T. I.

2017-11-01

Eta Carinae is one of the most massive observable binaries. Yet determination of its orbital and physical parameters is hampered by obscuring winds. However the effects of the strong, colliding winds changes with phase due to the high orbital eccentricity. We wanted to improve measures of the orbital parameters and to determine the mechanisms that produce the relatively brief, phase-locked minimum as detected throughout the electromagnetic spectrum. We conducted intense monitoring of the He ii λ4686 line in η Carinae for 10 months in the year 2014, gathering ~300 high S/N spectra with ground- and space-based telescopes. We also used published spectra at the FOS4 SE polar region of the Homunculus, which views the minimum from a different direction. We used a model in which the He ii λ4686 emission is produced by two mechanisms: a) one linked to the intensity of the wind-wind collision which occurs along the whole orbit and is proportional to the inverse square of the separation between the companion stars; and b) the other produced by the `bore hole' effect which occurs at phases across the periastron passage. The opacity (computed from 3D SPH simulations) as convolved with the emission reproduces the behavior of equivalent widths both for direct and reflected light. Our main results are: a) a demonstration that the He ii λ4686 light curve is exquisitely repeatable from cycle to cycle, contrary to previous claims for large changes; b) an accurate determination of the longitude of periastron, indicating that the secondary star is `behind' the primary at periastron, a dispute extended over the past decade; c) a determination of the time of periastron passage, at ~4 days after the onset of the deep light curve minimum; and d) show that the minimum is simultaneous for observers at different lines of sight, indicating that it is not caused by an eclipse of the secondary star, but rather by the immersion of the wind-wind collision interior to the inner wind of the primary.

Cheetah: Starspot modeling code

NASA Astrophysics Data System (ADS)

Walkowicz, Lucianne; Thomas, Michael; Finkestein, Adam

2014-12-01

Cheetah models starspots in photometric data (lightcurves) by calculating the modulation of a light curve due to starspots. The main parameters of the program are the linear and quadratic limb darkening coefficients, stellar inclination, spot locations and sizes, and the intensity ratio of the spots to the stellar photosphere. Cheetah uses uniform spot contrast and the minimum number of spots needed to produce a good fit and ignores bright regions for the sake of simplicity.

Optical detector calibrator system

NASA Technical Reports Server (NTRS)

Strobel, James P. (Inventor); Moerk, John S. (Inventor); Youngquist, Robert C. (Inventor)

1996-01-01

An optical detector calibrator system simulates a source of optical radiation to which a detector to be calibrated is responsive. A light source selected to emit radiation in a range of wavelengths corresponding to the spectral signature of the source is disposed within a housing containing a microprocessor for controlling the light source and other system elements. An adjustable iris and a multiple aperture filter wheel are provided for controlling the intensity of radiation emitted from the housing by the light source to adjust the simulated distance between the light source and the detector to be calibrated. The geared iris has an aperture whose size is adjustable by means of a first stepper motor controlled by the microprocessor. The multiple aperture filter wheel contains neutral density filters of different attenuation levels which are selectively positioned in the path of the emitted radiation by a second stepper motor that is also controlled by the microprocessor. An operator can select a number of detector tests including range, maximum and minimum sensitivity, and basic functionality. During the range test, the geared iris and filter wheel are repeatedly adjusted by the microprocessor as necessary to simulate an incrementally increasing simulated source distance. A light source calibration subsystem is incorporated in the system which insures that the intensity of the light source is maintained at a constant level over time.

Time-resolved fluorescence of thioredoxin single-tryptophan mutants: modeling experimental results with minimum perturbation mapping

NASA Astrophysics Data System (ADS)

Silva, Norberto D., Jr.; Haydock, Christopher; Prendergast, Franklyn G.

1994-08-01

The time-resolved fluorescence decay of single tryptophan (Trp) proteins is typically described using either a distribution of lifetimes or a sum of two or more exponential terms. A possible interpretation for this fluorescence decay heterogeneity is the existence of different isomeric conformations of Trp about its (chi) +1) and (chi) +2) dihedral angles. Are multiple Trp conformations compatible with the remainder of the protein in its crystallographic configuration or do they require repacking of neighbor side chains? It is conceivable that isomers of the neighbor side chains interconvert slowly on the fluorescence timescale and contribute additional lifetime components to the fluorescence intensity. We have explored this possibility by performing minimum perturbation mapping simulations of Trp 28 and Trp 31 in thioredoxin (TRX) using CHARMm 22. Mappings of Trp 29 and Trp 31 give the TRX Trp residue energy landscape as a function of (chi) +1) and (chi) +2) dihedral angles. Time-resolved fluorescence intensity and anisotropy decay of mutant TRX (W28F and W31F) are measured and interpreted in light of the above simulations. Relevant observables, like order parameters and isomerization rates, can be derived from the minimum perturbation maps and compared with experiment.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Wenfang; Du, Jinjin; Wen, Ruijuan

We have investigated the transmission spectra of a Fabry-Perot interferometer (FPI) with squeezed vacuum state injection and non-Gaussian detection, including photon number resolving detection and parity detection. In order to show the suitability of the system, parallel studies were made of the performance of two other light sources: coherent state of light and Fock state of light either with classical mean intensity detection or with non-Gaussian detection. This shows that by using the squeezed vacuum state and non-Gaussian detection simultaneously, the resolution of the FPI can go far beyond the cavity standard bandwidth limit based on the current techniques. Themore » sensitivity of the scheme has also been explored and it shows that the minimum detectable sensitivity is better than that of the other schemes.« less

Assessment of a smartphone-based camera for fundus imaging in animals.

PubMed

Balland, Olivier; Russo, Andrea; Isard, Pierre-François; Mathieson, Iona; Semeraro, Francesco; Dulaurent, Thomas

2017-01-01

To assess the use of an optical device (D-EYE; Si14 S.p.A.) attached to a modern smartphone (iPhone 5; Apple Inc.) for imaging the fundus in small animals. Five dogs, five cats, and five rabbits with clear media were imaged using a prototype of the D-EYE. The optical device was composed of lenses, polarizing filters, a beam splitter, a diaphragm, and mirrors, attached to a smartphone via a metal shell. Images were obtained 20 min after pupil dilation with topical 0.5% tropicamide in a darkened room, to ensure maximum pupillary dilation. Focus was set to the infinite when the autofocus was overwhelmed. Light intensity was adapted to each animal via the application (minimum light intensity for imaging the tapetal region, maximum light intensity for imaging the nontapetal region). Both still images and video sequences were recorded for each animal. Posterior segment structures were visible in all animals: optic nerve head, tapetum lucidum (when present), nontapetal region, retinal vessels, and choroidal vessels (when the retinal pigment epithelium and the choroidal pigmentation were discreet). Focal light artifacts were common when photographing the tapetum lucidum. Recording videos allowed the visualization of dynamic phenomena. The D-EYE assessed appears to be an easy means of obtaining images of the posterior segment structures. © 2016 American College of Veterinary Ophthalmologists.

Mycosporine-like amino acids and xanthophyll-cycle pigments favour a massive spring bloom development of the dinoflagellate Prorocentrum minimum in Grande Bay (Argentina), an ozone hole affected area

NASA Astrophysics Data System (ADS)

Carreto, José I.; Carignan, Mario O.; Montoya, Nora G.; Cozzolino, Ezequiel; Akselman, Rut

2018-02-01

In Grande Bay (Southern Patagonian Shelf) in a eutrophic and recirculating area slightly stratified during spring, we observed an intense (up to 1 × 107 cells L- 1) and shallow, quasi mono-specific bloom of the dinoflagellate Prorocentrum minimum. Peridinin was the most abundant carotenoid, but the relative amounts of the xanthophyll cycle carotenoids (diadinoxanthin + diatoxanthin = DT) to light-harvesting pigments were high (DT/Chl a ratio = 0.32 and DT/peridinin ratio = 0.40). Shinorine, usujirene, palythene, mycosporine-serine-glycine methyl ester and palythenic acid were the primary mycosporine-like amino acids (MAAs), followed by mycosporine-glycine, palythine, and porphyra-334. The ΣMAAs/Chl a ratios (up to 27.9 nmol/nmol) were in the upper range reported either in nutrient-replete dinoflagellate cultures or natural populations. We monitored, from space (using satellite ocean colour data), the spatial and temporal bloom variability (from September 22 to October 31, 2005) using an approach to discriminate dinoflagellate from diatom blooms. The results indicated that an intense diatom bloom started in early spring but was rapidly replaced by an intense bloom of the dinoflagellate P. minimum, although the nutrient concentrations were apparently not limiting. The most notorious change in this period was a sharp increase in the levels of solar UVB radiation (UVB index 9.0) as a consequence of the overpass of the polar vortex over this area. We postulated that the synthesis and accumulation of MAAs and xanthophyll pigments, were competitive advantages for the opportunistic red tide dinoflagellate P. minimum over the sensitive diatoms, favouring the development of their surface blooms in this seasonally solar UVB radiation (UVBR) affected area.

Scattering-Type Surface-Plasmon-Resonance Biosensors

NASA Technical Reports Server (NTRS)

Wang, Yu; Pain, Bedabrata; Cunningham, Thomas; Seshadri, Suresh

2005-01-01

Biosensors of a proposed type would exploit scattering of light by surface plasmon resonance (SPR). Related prior biosensors exploit absorption of light by SPR. Relative to the prior SPR biosensors, the proposed SPR biosensors would offer greater sensitivity in some cases, enough sensitivity to detect bioparticles having dimensions as small as nanometers. A surface plasmon wave can be described as a light-induced collective oscillation in electron density at the interface between a metal and a dielectric. At SPR, most incident photons are either absorbed or scattered at the metal/dielectric interface and, consequently, reflected light is greatly attenuated. The resonance wavelength and angle of incidence depend upon the permittivities of the metal and dielectric. An SPR sensor of the type most widely used heretofore includes a gold film coated with a ligand a substance that binds analyte molecules. The gold film is thin enough to support evanescent-wave coupling through its thickness. The change in the effective index of refraction at the surface, and thus the change in the SPR response, increases with the number of bound analyte molecules. The device is illuminated at a fixed wavelength, and the intensity of light reflected from the gold surface opposite the ligand-coated surface is measured as a function of the angle of incidence. From these measurements, the angle of minimum reflection intensity is determined

Carbon metabolism of the cryptoendolithic microbiota from the Antarctic desert

NASA Technical Reports Server (NTRS)

Vestal, J. R.; Friedmann, E. I. (Principal Investigator)

1988-01-01

The carbon metabolism of the cryptoendolithic microbiota of sandstones from the Ross Desert of Antarctica was studied in situ and in vitro. Organic and inorganic carbon compounds were metabolized by the microbiota, with bicarbonate incorporation into community lipids occurring primarily in the light. Light intensity affected the photometabolism of carbon with a photosynthesis-intensity response optimum at about 200 to 300 micromoles of photons per m2 per s. Photosynthesis was also affected by temperature, with a minimum activity at -5 degrees C, an optimum activity at 15 degrees C, and complete inhibition at 35 degrees C, indicating that the cryptoendolithic community was psychrophilic. The primary source of CO2 for photosynthesis in situ was the atmosphere. CO2 may also be photometabolized by using the carbon produced from respiration within the endolithic community. Photosynthesis occurred maximally when the microbiota was wet with liquid water and to a lesser extent in a humid atmosphere. This simple microbial community, therefore, exists under extremes of water, light, and temperature stress which affect and control its metabolism.

Linking chloroplast relocation to different responses of photosynthesis to blue and red radiation in low and high light-acclimated leaves of Arabidopsis thaliana (L.).

PubMed

Pfündel, Erhard E; Latouche, Gwendal; Meister, Armin; Cerovic, Zoran G

2018-01-27

Low light (LL) and high light (HL)-acclimated plants of A. thaliana were exposed to blue (BB) or red (RR) light or to a mixture of blue and red light (BR) of incrementally increasing intensities. The light response of photosystem II was measured by pulse amplitude-modulated chlorophyll fluorescence and that of photosystem I by near infrared difference spectroscopy. The LL but not HL leaves exhibited blue light-specific responses which were assigned to relocation of chloroplasts from the dark to the light-avoidance arrangement. Blue light (BB and BR) decreased the minimum fluorescence ([Formula: see text]) more than RR light. This extra reduction of the [Formula: see text] was stronger than theoretically predicted for [Formula: see text] quenching by energy dissipation but actual measurement and theory agreed in RR treatments. The extra [Formula: see text] reduction was assigned to decreased light absorption of chloroplasts in the avoidance position. A maximum reduction of 30% was calculated. Increasing intensities of blue light affected the fluorescence parameters NPQ and q P to a lesser degree than red light. After correcting for the optical effects of chloroplast relocation, the NPQ responded similarly to blue and red light. The same correction method diminished the color-specific variations in q P but did not abolish it; thus strongly indicating the presence of another blue light effect which also moderates excitation pressure in PSII but cannot be ascribed to absorption variations. Only after RR exposure, a post-illumination overshoot of [Formula: see text] and fast oxidation of PSI electron acceptors occurred, thus, suggesting an electron flow from stromal reductants to the plastoquinone pool.

Time-dependent scattering of incident light of various wavelengths in ferrofluids under external magnetic field

NASA Astrophysics Data System (ADS)

Jin, Jingyu; Song, Dongxing; Geng, Jiafeng; Jing, Dengwei

2018-02-01

Ferrofluids can exhibit the anisotropic thermodynamic properties under magnetic fields. The dynamic optical properties of ferrofluids in the presence of magnetic fields are of particular interest due to their potential application as various optical devices. Although time-dependent light scattering by ferrofluids have been extensively studied, the effect of wavelength of incident light have been rarely considered. Here, for the first time, we investigated both the time- and wavelength-dependent light scattering in water based ferrofluids containing Fe3O4 nanoparticles under an external magnetic field. The field-induced response behavior of the prepared ferrofluid samples was determined and verified first by thermal conductivity measurement and numerical simulation. Double-beam UV-Vis spectrophotometer was employed to record the temporal evolution of transmitted intensity of incident light of various wavelengths passing through the ferrofluid sample and propagating parallel to the applied field. As expected, the light intensity decreases to a certain value right after the field is turned on due to the thermal fluctuation induced disorder inside the flexible particle chains. Then the light intensity further decreases with time until the appearance of a minimum at time τ0 followed by an inversed increase before finally reaches equilibrium at a particular time. More importantly, the characteristic inversion time τ0 was found to follow a power law increase with the wavelength of incident light (τ0 ∼ λα, where α = 2.07). A quantitative explanation for the wavelength dependence of characteristic time was proposed based on the finite-difference time-domain (FDTD) method. The simulation results are in good agreement with our experimental observations. The time-dependent light scattering in ferrofluids under different incident wavelengths was rationalized by considering both the coarsening process of the particle chains and the occurrence of resonance within the magnetic scatterers. Our finding should be of value for the development of various light-tunable optical devices.

Hiding Information Using different lighting Color images

NASA Astrophysics Data System (ADS)

Majead, Ahlam; Awad, Rash; Salman, Salema S.

2018-05-01

The host medium for the secret message is one of the important principles for the designers of steganography method. In this study, the best color image was studied to carrying any secret image.The steganography approach based Lifting Wavelet Transform (LWT) and Least Significant Bits (LSBs) substitution. The proposed method offers lossless and unnoticeable changes in the contrast carrier color image and imperceptible by human visual system (HVS), especially the host images which was captured in dark lighting conditions. The aim of the study was to study the process of masking the data in colored images with different light intensities. The effect of the masking process was examined on the images that are classified by a minimum distance and the amount of noise and distortion in the image. The histogram and statistical characteristics of the cover image the results showed the efficient use of images taken with different light intensities in hiding data using the least important bit substitution method. This method succeeded in concealing textual data without distorting the original image (low light) Lire developments due to the concealment process.The digital image segmentation technique was used to distinguish small areas with masking. The result is that smooth homogeneous areas are less affected as a result of hiding comparing with high light areas. It is possible to use dark color images to send any secret message between two persons for the purpose of secret communication with good security.

Solar Power for Near Sun, High-Temperature Missions

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.

2008-01-01

Existing solar cells lose performance at the high temperatures encountered in Mercury orbit and inward toward the sun. For future missions designed to probe environments close to the sun, it is desirable to develop array technologies for high temperature and high light intensity. Approaches to solar array design for near-sun missions include modifying the terms governing temperature of the cell and the efficiency at elevated temperature, or use of techniques to reduce the incident solar energy to limit operating temperature. An additional problem is found in missions that involve a range of intensities, such as the Solar Probe + mission, which ranges from a starting distance of 1 AU from the sun to a minimum distance of 9.5 solar radii, or 0.044 AU. During the mission, the solar intensity ranges from one to about 500 times AM0. This requires a power system to operate over nearly three orders of magnitude of incident intensity.

An integration time adaptive control method for atmospheric composition detection of occultation

NASA Astrophysics Data System (ADS)

Ding, Lin; Hou, Shuai; Yu, Fei; Liu, Cheng; Li, Chao; Zhe, Lin

2018-01-01

When sun is used as the light source for atmospheric composition detection, it is necessary to image sun for accurate identification and stable tracking. In the course of 180 second of the occultation, the magnitude of sun light intensity through the atmosphere changes greatly. It is nearly 1100 times illumination change between the maximum atmospheric and the minimum atmospheric. And the process of light change is so severe that 2.9 times per second of light change can be reached. Therefore, it is difficult to control the integration time of sun image camera. In this paper, a novel adaptive integration time control method for occultation is presented. In this method, with the distribution of gray value in the image as the reference variable, and the concepts of speed integral PID control, the integration time adaptive control problem of high frequency imaging. The large dynamic range integration time automatic control in the occultation can be achieved.

Phase-shifting response to light in older adults

PubMed Central

Kim, Seong Jae; Benloucif, Susan; Reid, Kathryn Jean; Weintraub, Sandra; Kennedy, Nancy; Wolfe, Lisa F; Zee, Phyllis C

2014-01-01

Abstract Age-related changes in circadian rhythms may contribute to the sleep disruption observed in older adults. A reduction in responsiveness to photic stimuli in the circadian timing system has been hypothesized as a possible reason for the advanced circadian phase in older adults. This project compared phase-shifting responses to 2 h of broad-spectrum white light at moderate and high intensities in younger and older adults. Subjects included 29 healthy young (25.1 ± 4.1 years; male to female ratio: 8: 21) and 16 healthy older (66.5 ± 6.0 years; male to female ratio: 5: 11) subjects, who participated in two 4-night and 3-day laboratory stays, separated by at least 3 weeks. Subjects were randomly assigned to one of three different time-points, 8 h before (−8), 3 h before (−3) or 3 h after (+3) the core body temperature minimum (CBTmin) measured on the baseline night. For each condition, subjects were exposed in a randomized order to 2 h light pulses of two intensities (2000 lux and 8000 lux) during the two different laboratory stays. Phase shifts were analysed according to the time of melatonin midpoint on the nights before and after light exposure. Older subjects in this study showed an earlier baseline phase and lower amplitude of melatonin rhythm compared to younger subjects, but there was no evidence of age-related changes in the magnitude or direction of phase shifts of melatonin midpoint in response to 2 h of light at either 2000 lux or 8000 lux. These results indicate that the acute phase-shifting response to moderate- or high-intensity broad spectrum light is not significantly affected by age. PMID:24144880

Compensation for the phase-type spatial periodic modulation of the near-field beam at 1053 nm

NASA Astrophysics Data System (ADS)

Gao, Yaru; Liu, Dean; Yang, Aihua; Tang, Ruyu; Zhu, Jianqiang

2017-10-01

A phase-only spatial light modulator is used to provide and compensate for the spatial periodic modulation (SPM) of the near-field beam at the near infrared at 1053nm wavelength with an improved iterative weight-based method. The transmission characteristics of the incident beam has been changed by a spatial light modulator (SLM) to shape the spatial intensity of the output beam. The propagation and reverse propagation of the light in free space are two important processes in the iterative process. The based theory is the beam angular spectrum transmit formula (ASTF) and the principle of the iterative weight-based method. We have made two improvements to the originally proposed iterative weight-based method. We select the appropriate parameter by choosing the minimum value of the output beam contrast degree and use the MATLAB built-in angle function to acquire the corresponding phase of the light wave function. The required phase that compensates for the intensity distribution of the incident SPM beam is iterated by this algorithm, which can decrease the magnitude of the SPM of the intensity on the observation plane. The experimental results show that the phase-type SPM of the near-field beam is subject to a certain restriction. We have also analyzed some factors that make the results imperfect. The experiment results verifies the possible applicability of this iterative weight-based method to compensate for the SPM of the near-field beam.

Nonlinear side effects of fs pulses inside corneal tissue during photodisruption

NASA Astrophysics Data System (ADS)

Heisterkamp, A.; Ripken, T.; Mamom, T.; Drommer, W.; Welling, H.; Ertmer, W.; Lubatschowski, H.

In order to evaluate the potential for refractive surgery, fs laser pulses of 150-fs pulse duration were used to process corneal tissue of dead and living animal eyes. By focusing the laser radiation down to spot sizes of several microns, very precise cuts could be achieved inside the treated cornea, accompanied with minimum collateral damage to the tissue by thermal or mechanical effects. During histo-pathological analysis by light and transmission electron microscopy considerable side effects of fs photodisruption were found. Due to the high intensities at the focal region several nonlinear effects occurred. Self-focusing, photodissociation, UV-light production were observed, leading to streak formation inside the cornea.

Effects of water stress and light intensity on chlorophyll fluorescence parameters and pigments of Aloe vera L.

PubMed

Hazrati, Saeid; Tahmasebi-Sarvestani, Zeinolabedin; Modarres-Sanavy, Seyed Ali Mohammad; Mokhtassi-Bidgoli, Ali; Nicola, Silvana

2016-09-01

Aloe vera L. is one of the most important medicinal plants in the world. In order to determine the effects of light intensity and water deficit stress on chlorophyll (Chl) fluorescence and pigments of A. vera, a split-plot in time experiment was laid out in a randomized complete block design with four replications in a research greenhouse. The factorial combination of three light intensities (50, 75 and 100% of sunlight) and four irrigation regimes (irrigation after depleting 20, 40, 60 and 80% of soil water content) were considered as main factors. Sampling time was considered as sub factor. The first, second and third samplings were performed 90, 180 and 270 days after imposing the treatments, respectively. The results demonstrated that the highest light intensity and the severe water stress decreased maximum fluorescence (Fm), variable fluorescence (Fv)/Fm, quantum yield of PSII photochemistry (ФPSII), Chl and photochemical quenching (qP) but increased non-photochemical quenching (NPQ), minimum fluorescence (F0) and Anthocyanin (Anth). Additionally, the highest Fm, Fv/Fm, ФPSII and qP and the lowest NPQ and F0 were observed when 50% of sunlight was blocked and irrigation was done after 40% soil water depletion. Irradiance of full sunlight and water deficit stress let to the photoinhibition of photosynthesis, as indicated by a reduced quantum yield of PSII, ФPSII, and qP, as well as higher NPQ. Thus, chlorophyll florescence measurements provide valuable physiological data. Close to half of total solar radiation and irrigation after depleting 40% of soil water content were selected as the most efficient treatments. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Estimation of Rain Intensity Spectra over the Continental US Using Ground Radar-Gauge Measurements

NASA Technical Reports Server (NTRS)

Lin, Xin; Hou, Arthur Y.

2013-01-01

A high-resolution surface rainfall product is used to estimate rain characteristics over the continental US as a function of rain intensity. By defining each data at 4-km horizontal resolutions and 1-h temporal resolutions as an individual precipitating/nonprecipitating sample, statistics of rain occurrence and rain volume including their geographical and seasonal variations are documented. Quantitative estimations are also conducted to evaluate the impact of missing light rain events due to satellite sensors' detection capabilities. It is found that statistics of rain characteristics have large seasonal and geographical variations across the continental US. Although heavy rain events (> 10 mm/hr.) only occupy 2.6% of total rain occurrence, they may contribute to 27% of total rain volume. Light rain events (< 1.0 mm/hr.), occurring much more frequently (65%) than heavy rain events, can also make important contributions (15%) to the total rain volume. For minimum detectable rain rates setting at 0.5 and 0.2 mm/hr which are close to sensitivities of the current and future space-borne precipitation radars, there are about 43% and 11% of total rain occurrence below these thresholds, and they respectively represent 7% and 0.8% of total rain volume. For passive microwave sensors with their rain pixel sizes ranging from 14 to 16 km and the minimum detectable rain rates around 1 mm/hr., the missed light rain events may account for 70% of train occurrence and 16% of rain volume. Statistics of rain characteristics are also examined on domains with different temporal and spatial resolutions. Current issues in estimates of rain characteristics from satellite measurements and model outputs are discussed.

UV dose measurements of photosensitive dermatosis patients by polycrystalline GaN-based portable self-data-acquisition UV monitors.

PubMed

Yagi, Shigeru; Iwanaga, Takeshi; Kojima, Hiroshi; Shoji, Yoshio; Suzuki, Seiji; Seno, Kunihiro; Mori, Hisayoshi; Tokura, Yoshiki; Takigawa, Masahiro; Moriwaki, Shin-Ichi

2002-12-01

We have developed a UV monitor with polycrystalline (poly-) gallium nitride (GaN) UV sensors and evaluated its performance from the viewpoint of its effectiveness for use with photosensitive dermatosis patients. The poly-GaN UV sensor is sensitive to UV light from 280 to 410 nm even without optical filters. The UV monitor is a portable self-data-acquisition instrument with a minimum detection level (defined as average UV intensity over 290 to 400 nm) of 2 microW/cm2 and can store UV dose data for 128 days. It allows easy measurement of four orders of magnitude of ambient UV intensity and dose from indoor light to direct solar radiation in summer. Trial use of the UV monitor by five xeroderma pigmentosum patients started in June 2000 and was carried out for 1 year. It was demonstrated that the UV monitor was useful in improving their quality of life.

Far field emission profile of pure wurtzite InP nanowires

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bulgarini, Gabriele, E-mail: g.bulgarini@tudelft.nl; Reimer, Michael E.; Zwiller, Val

2014-11-10

We report on the far field emission profile of pure wurtzite InP nanowires in comparison to InP nanowires with predominantly zincblende crystal structure. The emission profile is measured on individual nanowires using Fourier microscopy. The most intense photoluminescence of wurtzite nanowires is collected at small angles with respect to the nanowire growth axis. In contrast, zincblende nanowires present a minimum of the collected light intensity in the direction of the nanowire growth. Results are explained by the orientation of electric dipoles responsible for the photoluminescence, which is different from wurtzite to zincblende. Wurtzite nanowires have dipoles oriented perpendicular to themore » nanowire growth direction, whereas zincblende nanowires have dipoles oriented along the nanowire axis. This interpretation is confirmed by both numerical simulations and polarization dependent photoluminescence spectroscopy. Knowledge of the dipole orientation in nanostructures is crucial for developing a wide range of photonic devices such as light-emitting diodes, photodetectors, and solar cells.« less

Super-Resolution Imaging of a Dielectric Microsphere Is Governed by the Waist of Its Photonic Nanojet.

PubMed

Yang, Hui; Trouillon, Raphaël; Huszka, Gergely; Gijs, Martin A M

2016-08-10

Dielectric microspheres with appropriate refractive index can image objects with super-resolution, that is, with a precision well beyond the classical diffraction limit. A microsphere is also known to generate upon illumination a photonic nanojet, which is a scattered beam of light with a high-intensity main lobe and very narrow waist. Here, we report a systematic study of the imaging of water-immersed nanostructures by barium titanate glass microspheres of different size. A numerical study of the light propagation through a microsphere points out the light focusing capability of microspheres of different size and the waist of their photonic nanojet. The former correlates to the magnification factor of the virtual images obtained from linear test nanostructures, the biggest magnification being obtained with microspheres of ∼6-7 μm in size. Analyzing the light intensity distribution of microscopy images allows determining analytically the point spread function of the optical system and thereby quantifies its resolution. We find that the super-resolution imaging of a microsphere is dependent on the waist of its photonic nanojet, the best resolution being obtained with a 6 μm Ø microsphere, which generates the nanojet with the minimum waist. This comparison allows elucidating the super-resolution imaging mechanism.

Solution-processed nanoparticle super-float-gated organic field-effect transistor as un-cooled ultraviolet and infrared photon counter.

PubMed

Yuan, Yongbo; Dong, Qingfeng; Yang, Bin; Guo, Fawen; Zhang, Qi; Han, Ming; Huang, Jinsong

2013-01-01

High sensitivity photodetectors in ultraviolet (UV) and infrared (IR) range have broad civilian and military applications. Here we report on an un-cooled solution-processed UV-IR photon counter based on modified organic field-effect transistors. This type of UV detectors have light absorbing zinc oxide nanoparticles (NPs) sandwiched between two gate dielectric layers as a floating gate. The photon-generated charges on the floating gate cause high resistance regions in the transistor channel and tune the source-drain output current. This "super-float-gating" mechanism enables very high sensitivity photodetectors with a minimum detectable ultraviolet light intensity of 2.6 photons/μm(2)s at room temperature as well as photon counting capability. Based on same mechansim, infrared photodetectors with lead sulfide NPs as light absorbing materials have also been demonstrated.

Transmitted light relaxation and microstructure evolution of ferrofluids under gradient magnetic fields

NASA Astrophysics Data System (ADS)

Huang, Yan; Li, Decai; Li, Feng; Zhu, Quanshui; Xie, Yu

2015-03-01

Using light transmission experiments and optical microscope observations with a longitudinal gradient magnetic field configuration, the relationship between the behavior of the transmitted light relaxation and the microstructure evolution of ionic ferrofluids in the central region of an axisymmetric field is investigated. Under a low-gradient magnetic field, there are two types of relaxation process. When a field is applied, the transmitted light intensity decreases to a minimum within a time on the order of 101-102 s. It is then gradually restored, approaching its initial value within a time on the order of 102 s. This is type I relaxation, which corresponds to the formation of magnetic columns. After the transmission reaches this value, it either increases or decreases slowly, stabilizing within a time on the order of 103 s, according to the direction of the field gradient. This is a type II relaxation, which results from the shadowing effect, corresponding to the motion of the magnetic columns under the application of a gradient force. Under a magnetic field with a centripetal high-gradient (magnetic materials subjected to a force pointing toward the center of the axisymmetric field), the transmitted light intensity decreases monotonously and more slowly than that under a low-gradient field. Magnetic transport and separation resulted from magnetophoresis under high-gradient fields, changing the formation dynamics of the local columns and influencing the final state of the column system.

A real-time monitoring system for night glare protection

NASA Astrophysics Data System (ADS)

Ma, Jun; Ni, Xuxiang

2010-11-01

When capturing a dark scene with a high bright object, the monitoring camera will be saturated in some regions and the details will be lost in and near these saturated regions because of the glare vision. This work aims at developing a real-time night monitoring system. The system can decrease the influence of the glare vision and gain more details from the ordinary camera when exposing a high-contrast scene like a car with its headlight on during night. The system is made up of spatial light modulator (The liquid crystal on silicon: LCoS), image sensor (CCD), imaging lens and DSP. LCoS, a reflective liquid crystal, can modular the intensity of reflective light at every pixel as a digital device. Through modulation function of LCoS, CCD is exposed with sub-region. With the control of DSP, the light intensity is decreased to minimum in the glare regions, and the light intensity is negative feedback modulated based on PID theory in other regions. So that more details of the object will be imaging on CCD and the glare protection of monitoring system is achieved. In experiments, the feedback is controlled by the embedded system based on TI DM642. Experiments shows: this feedback modulation method not only reduces the glare vision to improve image quality, but also enhances the dynamic range of image. The high-quality and high dynamic range image is real-time captured at 30hz. The modulation depth of LCoS determines how strong the glare can be removed.

Energy Balance for a Sonoluminescence Bubble Yields a Measure of Ionization Potential Lowering

NASA Astrophysics Data System (ADS)

Kappus, B.; Bataller, A.; Putterman, S. J.

2013-12-01

Application of energy conservation between input sound and the microplasma which forms at the moment of sonoluminescence places bounds on the process, whereby the gas is ionized. Detailed pulsed Mie scattering measurements of the radius versus time for a xenon bubble in sulfuric acid provide a complete characterization of the hydrodynamics and minimum radius. For a range of emission intensities, the blackbody spectrum emitted during collapse matches the minimum bubble radius, implying opaque conditions are attained. This requires a degree of ionization >36%. Analysis reveals only 2.1±0.6eV/atom of energy available during light emission. In order to unbind enough charge, collective processes must therefore reduce the ionization potential by at least 75%. We interpret this as evidence that a phase transition to a highly ionized plasma is occurring during sonoluminescence.

Energy balance for a sonoluminescence bubble yields a measure of ionization potential lowering.

PubMed

Kappus, B; Bataller, A; Putterman, S J

2013-12-06

Application of energy conservation between input sound and the microplasma which forms at the moment of sonoluminescence places bounds on the process, whereby the gas is ionized. Detailed pulsed Mie scattering measurements of the radius versus time for a xenon bubble in sulfuric acid provide a complete characterization of the hydrodynamics and minimum radius. For a range of emission intensities, the blackbody spectrum emitted during collapse matches the minimum bubble radius, implying opaque conditions are attained. This requires a degree of ionization >36%. Analysis reveals only 2.1±0.6  eV/atom of energy available during light emission. In order to unbind enough charge, collective processes must therefore reduce the ionization potential by at least 75%. We interpret this as evidence that a phase transition to a highly ionized plasma is occurring during sonoluminescence.

46 CFR 169.549 - Ring lifebuoys and water lights.

Code of Federal Regulations, 2014 CFR

2014-10-01

... chapter and be international orange in color. (2) Each water light must be approved under subpart 161.010... 46 Shipping 7 2014-10-01 2014-10-01 false Ring lifebuoys and water lights. 169.549 Section 169.549... lights. (a)(1) The minimum number of life buoys and the minimum number to which water lights must be...

46 CFR 169.549 - Ring lifebuoys and water lights.

Code of Federal Regulations, 2012 CFR

2012-10-01

... chapter and be international orange in color. (2) Each water light must be approved under subpart 161.010... 46 Shipping 7 2012-10-01 2012-10-01 false Ring lifebuoys and water lights. 169.549 Section 169.549... lights. (a)(1) The minimum number of life buoys and the minimum number to which water lights must be...

Is there a minimum intensity threshold for resistance training-induced hypertrophic adaptations?

PubMed

Schoenfeld, Brad J

2013-12-01

In humans, regimented resistance training has been shown to promote substantial increases in skeletal muscle mass. With respect to traditional resistance training methods, the prevailing opinion is that an intensity of greater than ~60 % of 1 repetition maximum (RM) is necessary to elicit significant increases in muscular size. It has been surmised that this is the minimum threshold required to activate the complete spectrum of fiber types, particularly those associated with the largest motor units. There is emerging evidence, however, that low-intensity resistance training performed with blood flow restriction (BFR) can promote marked increases in muscle hypertrophy, in many cases equal to that of traditional high-intensity exercise. The anabolic effects of such occlusion-based training have been attributed to increased levels of metabolic stress that mediate hypertrophy at least in part by enhancing recruitment of high-threshold motor units. Recently, several researchers have put forth the theory that low-intensity exercise (≤50 % 1RM) performed without BFR can promote increases in muscle size equal, or perhaps even superior, to that at higher intensities, provided training is carried out to volitional muscular failure. Proponents of the theory postulate that fatiguing contractions at light loads is simply a milder form of BFR and thus ultimately results in maximal muscle fiber recruitment. Current research indicates that low-load exercise can indeed promote increases in muscle growth in untrained subjects, and that these gains may be functionally, metabolically, and/or aesthetically meaningful. However, whether hypertrophic adaptations can equal that achieved with higher intensity resistance exercise (≤60 % 1RM) remains to be determined. Furthermore, it is not clear as to what, if any, hypertrophic effects are seen with low-intensity exercise in well-trained subjects as experimental studies on the topic in this population are lacking. Practical implications of these findings are discussed.

Design of a modified endoscope illuminator for spectral imaging of colorectal tissues

NASA Astrophysics Data System (ADS)

Browning, Craig M.; Mayes, Samuel; Rich, Thomas C.; Leavesley, Silas J.

2017-02-01

The gold standard for locating colonic polyps is a white light endoscope in a colonoscopy, however, polyps smaller than 5 mm can be easily missed. Modified procedures such as narrow band imaging have shown only marginal increases in detection rates. Spectral imaging is a potential solution to improve the sensitivity and specificity of colonoscopies by providing the ability to distinguish molecular fluorescence differences in tissues. The goal of this work is to implement a spectral endoscopic light source to acquire spectral image data of colorectal tissues. A beta-version endoscope light source was developed, by retrofitting a white light endoscope light source (Olympus, CLK-4) with 16 narrow band LEDs. This redesigned, beta-prototype uses high-power LEDs with a minimum output of 500 mW to provide sufficient spectral output (0.5 mW) through the endoscope. A mounting apparatus was designed to provide sufficient heat dissipation. Here, we report recent results of our tests to characterize the intensity output through the light source and endoscope to determine the flat spectral output for imaging and intensity losses through the endoscope. We also report preliminary spectral imaging data from transverse pig colon that demonstrates the ability to result in working practical spectral data. Preliminary results of this revised prototype spectral endoscope system demonstrate that there is sufficient power to allow the imaging process to continue and potentially determine spectral differences in cancerous and normal tissue from imaging ex vivo pairs. Future work will focus on building a spectral library for the colorectal region and refining the user interface the system for in vivo use.

Biokinetic model-based multi-objective optimization of Dunaliella tertiolecta cultivation using elitist non-dominated sorting genetic algorithm with inheritance.

PubMed

Sinha, Snehal K; Kumar, Mithilesh; Guria, Chandan; Kumar, Anup; Banerjee, Chiranjib

2017-10-01

Algal model based multi-objective optimization using elitist non-dominated sorting genetic algorithm with inheritance was carried out for batch cultivation of Dunaliella tertiolecta using NPK-fertilizer. Optimization problems involving two- and three-objective functions were solved simultaneously. The objective functions are: maximization of algae-biomass and lipid productivity with minimization of cultivation time and cost. Time variant light intensity and temperature including NPK-fertilizer, NaCl and NaHCO 3 loadings are the important decision variables. Algal model involving Monod/Andrews adsorption kinetics and Droop model with internal nutrient cell quota was used for optimization studies. Sets of non-dominated (equally good) Pareto optimal solutions were obtained for the problems studied. It was observed that time variant optimal light intensity and temperature trajectories, including optimum NPK fertilizer, NaCl and NaHCO 3 concentration has significant influence to improve biomass and lipid productivity under minimum cultivation time and cost. Proposed optimization studies may be helpful to implement the control strategy in scale-up operation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Polishing of anaerobic secondary effluent by Chlorella vulgaris under low light intensity.

PubMed

Cheng, Tuoyuan; Wei, Chun-Hai; Leiknes, TorOve

2017-10-01

To investigate anaerobic secondary effluent polishing by microalgae (Chlorella vulgaris) under low light intensity (14μmol/m 2 /s), bubbling column reactors were operated in batches of 8 d with initial ammonium nitrogen 10-50mg/L, initial phosphate phosphorus 2-10mg/L and microalgal seed 40mg/L. Maximum microalgal biomass and minimum generation time were 370.9mg/L and 2.5d, respectively. Nitrogen removal (maximum 99.6%) was mainly attributed to microalgal growth rate, while phosphorus removal (maximum 49.8%) was related to microalgal growth rate, cell phosphorus content (maximum 1.5%) and initial nutrients ratio. Dissolved microalgal organics release in terms of chemical oxygen demand (maximum 63.2mg/L) and hexane extractable material (i.e., oil and grease, maximum 8.5mg/L) was firstly reported and mainly affected by nitrogen deficiency and deteriorated effluent quality. Ultrafiltration critical flux (16.6-39.5L/m 2 /h) showed negative linear correlation to microalgal biomass. Anaerobic membrane bioreactor effluent polishing showed similar results with slight inhibition to synthetic effluent. Copyright © 2017 Elsevier Ltd. All rights reserved.

Lighting Condition Analysis for Mars' Moon Phobos

NASA Technical Reports Server (NTRS)

Li, Zu Qun; de Carufel, Guy; Crues, Edwin Z.; Bielski, Paul

2016-01-01

This study used high fidelity computer simulation to investigate the lighting conditions, specifically the solar radiation flux over the surface, on Phobos. Ephemeris data from the Jet Propulsion Laboratory (JPL) DE405 model was used to model the state of the Sun, Earth, Moon, and Mars. An occultation model was developed to simulate Phobos' self-shadowing and its solar eclipses by Mars. The propagated Phobos state was compared with data from JPL's Horizon system to ensure the accuracy of the result. Results for Phobos lighting conditions over one Martian year are presented, which include the duration of solar eclipses, average solar radiation intensity, surface exposure time, and radiant exposure for both sun tracking and fixed solar arrays. The results show that: Phobos' solar eclipse time varies throughout the Martian year, with longer eclipse durations during the Martian northern spring and fall seasons and no eclipses during the Martian northern summer and winter seasons; solar radiation intensity is close to minimum in late spring and close to maximum in late fall; exposure time per orbit is relatively constant over the surface during the spring and fall but varies with latitude during the summer and winter; and Sun tracking solar arrays generate more energy than a fixed solar array. A usage example of the result is also present in this paper to demonstrate the utility.

Optically Stimulated Luminescence (OSL) of Tooth Enamel and its Potential Use in Post-Radiation Exposure Triage

PubMed Central

DeWitt, R.; Klein, D. M.; Yukihara, E. G.; Simon, S. L.; McKeever, S. W. S.

2009-01-01

Optically stimulated luminescence (OSL) properties of dental enamel are discussed with a view to the development of an in-vivo dose assessment technique for medical triage following a radiological/nuclear accident or terrorist event. In the OSL technique, past radiation exposure is assessed by stimulating the sample with light of one wavelength and monitoring the luminescence at another wavelength under the assumption that the luminescence originates from the recombination of radiation-induced charges trapped at metastable defects in the enamel and that the intensity of the luminescence signal is in proportion to the absorbed radiation dose. Several primary findings emerged from this research: (a) sensitivities varied considerably between different teeth and also between fragments of the same tooth, (b) OSL signals were found to decay rapidly during the first 12 hours after irradiation and slower afterwards, (c) the fading rate of the luminescence signal varied between fragments, (d) blue light stimulation yields greater sensitivity than infra-red stimulation, while the OSL signal obtained with a high-intensity pulsed green-light laser was found to be not correlated with the radiation dose. Significant challenges remain to developing a practical in-vivo technique including the development of calibration procedures and lowering minimum detectable doses. PMID:20065717

Differential photosynthetic and morphological adaptations to low light affect depth distribution of two submersed macrophytes in lakes.

PubMed

Chen, Jianfeng; Cao, Te; Zhang, Xiaolin; Xi, Yilong; Ni, Leyi; Jeppesen, Erik

2016-10-03

To evaluate the relative importance of photosynthetic versus morphological adaptations of submersed macrophytes to low light intensity in lakes, rapid light curves (RLCs), morphological parameters, relative growth rate (RGR), clonal reproduction and abundance of two submersed macrophytes (Potamogeton maackianus and Vallisneria natans) were examined under 2.8%, 7.1%, 17.1% and 39.5% ambient light in a field and outdoor experimental study. The plants increased their initial slope of RLCs (α) and decreased their minimum saturating irradiance (E k ) and maximum relative electron transport rate (ETRm) of RLCs under low light stress, but V. natans was more sensitive in RLCs than P. maackianus. Accordingly, the RGR, plant height and abundance of P. maackianus were higher in the high light regimes (shallow water) but lower in the low light regimes than those of V. natans. At the 2.8% ambient light, V. natans produced ramets and thus fulfilled its population expansion, in contrast to P. maackianus. The results revealed that P. maackianus as a canopy-former mainly elongated its shoot length towards the water surface to compensate for the low light conditions, however, it became limited in severe low light stress conditions. V. natans as a rosette adapted to low light stress mainly through photosynthetic adjustments and superior to severely low light than shoot elongation.

Pulse Profiles, Accretion Column Dips and a Flare in GX 1+4 During a Faint State

NASA Technical Reports Server (NTRS)

Giles, A. B.; Galloway, D. K.; Greenhill, J. G.; Storey, M. C.; Wilson, C. A.

1999-01-01

The Rossi X-ray Timing Explorer (RXTE) spacecraft observed the X-ray GX 1+4 for it period of 34 hours on July 19/20 1996. The source faded front an intensity of approximately 20 mcrab to a minimum of <= 0.7 mcrab and then partially recovered towards the end of the observation. This extended minimum lasted approximately 40,000 seconds. Phase folded light curves at a barycentric rotation period of 124.36568 +/- 0.00020 seconds show that near the center of the extended minimum the source stopped pulsing in the traditional sense but retained a weak dip feature at the rotation period. Away from the extended minimum the dips are progressively narrower at higher energies and may be interpreted as obscurations or eclipses of the hot spot by the accretion column. The pulse profile changed from leading-edge bright before the extended minimum to trailing-edge bright after it. Data from the Burst and Transient Source Experiment (BATSE) show that a torque reversal occurred < 10 days after our observation. Our data indicate that the observed rotation departs from a constant period with a P/P value of approximately -1.5% per year at a 4.5sigma significance. We infer that we may have serendipitously obtained data, with high sensitivity and temporal resolution about the time of an accretion disk spin reversal. We also observed a rapid flare which had some precursor activity close to the center of the extended minimum.

Nonimaging reflectors for efficient uniform illumination.

PubMed

Gordon, J M; Kashin, P; Rabl, A

1992-10-01

Nonimaging reflectors that are an extension of the design principle that was developed for compound parabolic concentrator type devices are proposed for illumination applications. The optical designs presented offer maximal lighting efficiency while they retain sharp angular control of the radiation and highly uniform flux densities on distant target planes. Our results are presented for symmetrical configurations in two dimensions (troughlike reflectors) for flat and for tubular sources. For fields of view of practical interest (half-angle in the 30-60 degrees range), these devices can achieve minimum-tomaximum intensity ratios of 0.7, while they remain compact and incur low reflective losses.

Exercise Intensity and Incidence of Metabolic Syndrome: The SUN Project.

PubMed

Hidalgo-Santamaria, María; Fernandez-Montero, Alejandro; Martinez-Gonzalez, Miguel A; Moreno-Galarraga, Laura; Sanchez-Villegas, Almudena; Barrio-Lopez, María T; Bes-Rastrollo, Maira

2017-04-01

Emerging evidence suggests that vigorous physical activity may be associated with higher cardioprotective benefits than moderate physical activity. This study aimed to assess the long-term relationship between the intensity of leisure time physical activity (LTPA) and the risk of developing metabolic syndrome (MS) in a prospective cohort study. The Seguimiento Universidad de Navarra (SUN) Project comprises Spanish university graduates. Participants (n=10,145) initially free of MS were followed for a minimum of 6 years (2008-2014). Analysis was conducted in 2015. Physical activity was assessed though a validated questionnaire. The intensity of each physical activity was measured in METs. The intensity of LTPA was estimated by the ratio between total METs/week and total hours of LTPA/week, obtaining the mean METs/hour of LTPA. MS was defined according to the harmonizing definition. The association between the intensity of LTPA (METs/hour) and MS was assessed with logistic regression models adjusting for potential confounders. Among 10,145 participants initially free of any MS criteria, 412 new MS cases were observed. Vigorous LTPA was associated with a 37% relatively lower risk (AOR=0.63, 95% CI=0.44, 0.89) compared with light LTPA. For a given total energy expenditure, independent of the time spent on it, participants who performed vigorous LTPA exhibited a higher reduction in the risk of MS than those who performed light to moderate LTPA. Vigorous LTPA was significantly associated with lower risk of developing MS after a 6-year follow-up period. Copyright © 2016 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

Electro-optic polymeric reflection modulator based on plasmonic metamaterial

NASA Astrophysics Data System (ADS)

Abbas, A.; Swillam, M.

2018-02-01

A novel low power design for polymeric Electro-Optic reflection modulator is proposed based on the Extraordinary Reflection of light from multilayer structure consisting of a plasmonic metasurface with a periodic structure of sub wavelength circular apertures in a gold film above a thin layer of EO polymer and above another thin gold layer. The interference of the different reflected beams from different layer construct the modulated beam, The applied input driving voltage change the polymer refractive index which in turn determine whether the interference is constructive or destructive, so both phase and intensity modulation could be achieved. The resonant wavelength is tuned to the standard telecommunication wavelength 1.55μm, at this wavelength the reflection is minimum, while the absorption is maximum due to plasmonic resonance (PR) and the coupling between the incident light and the plasmonic metasurface.

Recent Studies of the Behavior of the Sun's White-Light Corona Over Time

NASA Technical Reports Server (NTRS)

SaintCyr, O. C.; Young, D. E.; Pesnell, W. D.; Lecinski, A.; Eddy, J.

2008-01-01

Predictions of upcoming solar cycles are often related to the nature and dynamics of the Sun's polar magnetic field and its influence on the corona. For the past 30 years we have a more-or-less continuous record of the Sun's white-light corona from groundbased and spacebased coronagraphs. Over that interval, the large scale features of the corona have varied in what we now consider a 'predictable' fashion--complex, showing multiple streamers at all latitudes during solar activity maximum; and a simple dipolar shape aligned with the rotational pole during solar minimum. Over the past three decades the white-light corona appears to be a better indicator of 'true' solar minimum than sunspot number since sunspots disappear for months (even years) at solar minimum. Since almost all predictions of the timing of the next solar maximum depend on the timing of solar minimum, the white-light corona is a potentially important observational discriminator for future predictors. In this contribution we describe recent work quantifying the large-scale appearance of the Sun's corona to correlate it with the sunspot record, especially around solar minimum. These three decades can be expanded with the HAO archive of eclipse photographs which, although sparse compared to the coronagraphic coverage, extends back to 1869. A more extensive understanding of this proxy would give researchers confidence in using the white-light corona as an indicator of solar minimum conditions.

Improved superficial brain hemorrhage visualization in susceptibility weighted images by constrained minimum intensity projection

NASA Astrophysics Data System (ADS)

Castro, Marcelo A.; Pham, Dzung L.; Butman, John

2016-03-01

Minimum intensity projection is a technique commonly used to display magnetic resonance susceptibility weighted images, allowing the observer to better visualize hemorrhages and vasculature. The technique displays the minimum intensity in a given projection within a thick slab, allowing different connectivity patterns to be easily revealed. Unfortunately, the low signal intensity of the skull within the thick slab can mask superficial tissues near the skull base and other regions. Because superficial microhemorrhages are a common feature of traumatic brain injury, this effect limits the ability to proper diagnose and follow up patients. In order to overcome this limitation, we developed a method to allow minimum intensity projection to properly display superficial tissues adjacent to the skull. Our approach is based on two brain masks, the largest of which includes extracerebral voxels. The analysis of the rind within both masks containing the actual brain boundary allows reclassification of those voxels initially missed in the smaller mask. Morphological operations are applied to guarantee accuracy and topological correctness, and the mean intensity within the mask is assigned to all outer voxels. This prevents bone from dominating superficial regions in the projection, enabling superior visualization of cortical hemorrhages and vessels.

Effects of maximum intensity aerobic swimming exercise until exhaustion at different times of day on the hematological parameters in rats.

PubMed

Beck, W; Gobatto, Claudio Alexandre

2013-12-01

The aims of this study were: a) to analyze the time of day effect on the aerobic capacity and time to exhaustion at aerobic capacity intensity (TE), and b) to analyze the physiological impact of handling and exercise testing during the light and dark periods, based on hematological parameters. Eighty rats were randomly divided into two control groups (C12 and C20) and two exercise groups (E12 and E20), assessed at 12:00 h (C12 and E12) or 20:00 h (C20 and E20). The lactate minimum intensity (LMi) was measured and after 48 h the exercise groups were subjected to a bout of swimming until exhaustion at LMi (TE). The TE was 1.30 ± 0.51 h for the E12 group and 1.81 ± 0.77 h for the E20 group (p = 0.03). The time of day effect was significant for all white blood cell counts (12:00 h > 20:00 h). Chronic handling and performing exercise tests at 12:00 h (light period) resulted in an increased WBC counts and decreased exercise tolerance. The favorable time of day for aerobic capacity and performance assessment and hematological parameters was at 20:00 h (dark period), which is associated with the wakefulness period of the assessed animals.

Lighting Condition Analysis for Mars' Moon Phobos

NASA Technical Reports Server (NTRS)

Li, Zu Qun; de Carufel, Guy; Crues, Edwin Z.; Bielski, Paul

2016-01-01

This study used high fidelity computer simulation to investigate the lighting conditions, specifically the solar radiation flux over the surface, on Phobos. Ephemeris data from the Jet Propulsion Laboratory (JPL) DE405 model was used to model the state of the Sun, Earth, Moon, and Mars. An occultation model was developed to simulate Phobos' self-shadowing and its solar eclipses by Mars. The propagated Phobos state was compared with data from JPL's Horizon system to ensure the accuracy of the result. Results for Phobos lighting conditions over one Martian year are presented, which include the duration of solar eclipses, average solar radiation intensity, surface exposure time, available energy per unit area for sun tracking arrays, and available energy per unit area for fixed arrays (constrained by incident angle). The results show that: Phobos' solar eclipse time varies throughout the Martian year, with longer eclipse durations during the Martian spring and fall seasons and no eclipses during the Martian summer and winter seasons; solar radiation intensity is close to minimum at the summer solstice and close to maximum at the winter solstice; exposure time per orbit is relatively constant over the surface during the spring and fall but varies with latitude during the summer and winter; and Sun tracking solar arrays generate more energy than a fixed solar array. A usage example of the result is also present in this paper to demonstrate the utility.

Barriers and facilitators to the implementation of an evidence-based electronic minimum dataset for nursing team leader handover: A descriptive survey.

PubMed

Spooner, Amy J; Aitken, Leanne M; Chaboyer, Wendy

2017-11-15

There is widespread use of clinical information systems in intensive care units however, the evidence to support electronic handover is limited. The study aim was to assess the barriers and facilitators to use of an electronic minimum dataset for nursing team leader shift-to-shift handover in the intensive care unit prior to its implementation. The study was conducted in a 21-bed medical/surgical intensive care unit, specialising in cardiothoracic surgery at a tertiary referral hospital, in Queensland, Australia. An established tool was modified to the intensive care nursing handover context and a survey of all 63 nursing team leaders was undertaken. Survey statements were rated using a 6-point Likert scale with selections from 'strongly disagree' to 'strongly agree', and open-ended questions. Descriptive statistics were used to summarise results. A total of 39 team leaders responded to the survey (62%). Team leaders used general intensive care work unit guidelines to inform practice however they were less familiar with the intensive care handover work unit guideline. Barriers to minimum dataset uptake included: a tool that was not user friendly, time consuming and contained too much information. Facilitators to minimum dataset adoption included: a tool that was user friendly, saved time and contained relevant information. Identifying the complexities of a healthcare setting prior to the implementation of an intervention assists researchers and clinicians to integrate new knowledge into healthcare settings. Barriers and facilitators to knowledge use focused on usability, content and efficiency of the electronic minimum dataset and can be used to inform tailored strategies to optimise team leaders' adoption of a minimum dataset for handover. Copyright © 2017 Australian College of Critical Care Nurses Ltd. Published by Elsevier Ltd. All rights reserved.

Developing a minimum dataset for nursing team leader handover in the intensive care unit: A focus group study.

PubMed

Spooner, Amy J; Aitken, Leanne M; Corley, Amanda; Chaboyer, Wendy

2018-01-01

Despite increasing demand for structured processes to guide clinical handover, nursing handover tools are limited in the intensive care unit. The study aim was to identify key items to include in a minimum dataset for intensive care nursing team leader shift-to-shift handover. This focus group study was conducted in a 21-bed medical/surgical intensive care unit in Australia. Senior registered nurses involved in team leader handovers were recruited. Focus groups were conducted using a nominal group technique to generate and prioritise minimum dataset items. Nurses were presented with content from previous team leader handovers and asked to select which content items to include in a minimum dataset. Participant responses were summarised as frequencies and percentages. Seventeen senior nurses participated in three focus groups. Participants agreed that ISBAR (Identify-Situation-Background-Assessment-Recommendations) was a useful tool to guide clinical handover. Items recommended to be included in the minimum dataset (≥65% agreement) included Identify (name, age, days in intensive care), Situation (diagnosis, surgical procedure), Background (significant event(s), management of significant event(s)) and Recommendations (patient plan for next shift, tasks to follow up for next shift). Overall, 30 of the 67 (45%) items in the Assessment category were considered important to include in the minimum dataset and focused on relevant observations and treatment within each body system. Other non-ISBAR items considered important to include related to the ICU (admissions to ICU, staffing/skill mix, theatre cases) and patients (infectious status, site of infection, end of life plan). Items were further categorised into those to include in all handovers and those to discuss only when relevant to the patient. The findings suggest a minimum dataset for intensive care nursing team leader shift-to-shift handover should contain items within ISBAR along with unit and patient specific information to maintain continuity of care and patient safety across shift changes. Copyright © 2017 Australian College of Critical Care Nurses Ltd. All rights reserved.

Suitable Environmental Ranges for Potential Coral Reef Habitats in the Tropical Ocean

PubMed Central

Guan, Yi; Hohn, Sönke; Merico, Agostino

2015-01-01

Coral reefs are found within a limited range of environmental conditions or tolerance limits. Estimating these limits is a critical prerequisite for understanding the impacts of climate change on the biogeography of coral reefs. Here we used the diagnostic model ReefHab to determine the current environmental tolerance limits for coral reefs and the global distribution of potential coral reef habitats as a function of six factors: temperature, salinity, nitrate, phosphate, aragonite saturation state, and light. To determine these tolerance limits, we extracted maximum and minimum values of all environmental variables in corresponding locations where coral reefs are present. We found that the global, annually averaged tolerance limits for coral reefs are 21.7—29.6 °C for temperature, 28.7—40.4 psu for salinity, 4.51 μmol L-1 for nitrate, 0.63 μmol L-1 for phosphate, and 2.82 for aragonite saturation state. The averaged minimum light intensity in coral reefs is 450 μmol photons m-2 s-1. The global area of potential reef habitats calculated by the model is 330.5 × 103 km2. Compared with previous studies, the tolerance limits for temperature, salinity, and nutrients have not changed much, whereas the minimum value of aragonite saturation in coral reef waters has decreased from 3.28 to 2.82. The potential reef habitat area calculated with ReefHab is about 121×103 km2 larger than the area estimated from the charted reefs, suggesting that the growth potential of coral reefs is higher than currently observed. PMID:26030287

Suitable environmental ranges for potential coral reef habitats in the tropical ocean.

PubMed

Guan, Yi; Hohn, Sönke; Merico, Agostino

2015-01-01

Coral reefs are found within a limited range of environmental conditions or tolerance limits. Estimating these limits is a critical prerequisite for understanding the impacts of climate change on the biogeography of coral reefs. Here we used the diagnostic model ReefHab to determine the current environmental tolerance limits for coral reefs and the global distribution of potential coral reef habitats as a function of six factors: temperature, salinity, nitrate, phosphate, aragonite saturation state, and light. To determine these tolerance limits, we extracted maximum and minimum values of all environmental variables in corresponding locations where coral reefs are present. We found that the global, annually averaged tolerance limits for coral reefs are 21.7-29.6 °C for temperature, 28.7-40.4 psu for salinity, 4.51 μmol L-1 for nitrate, 0.63 μmol L-1 for phosphate, and 2.82 for aragonite saturation state. The averaged minimum light intensity in coral reefs is 450 μmol photons m-2 s-1. The global area of potential reef habitats calculated by the model is 330.5 × 103 km2. Compared with previous studies, the tolerance limits for temperature, salinity, and nutrients have not changed much, whereas the minimum value of aragonite saturation in coral reef waters has decreased from 3.28 to 2.82. The potential reef habitat area calculated with ReefHab is about 121×103 km2 larger than the area estimated from the charted reefs, suggesting that the growth potential of coral reefs is higher than currently observed.

How Well Was the Sun Observed during the Maunder Minimum?

NASA Astrophysics Data System (ADS)

Hoyt, Douglas V.; Schatten, Kenneth H.

1996-04-01

In this paper we examine how well the Sun and sunspots were observed during the Maunder Minimum from 1645 to 1715. Recent research has given us the dates of observations by Hevelius, Picard, La Hire, Flamsteed, and about 70 other observers. These specific observations allow a ‘lower estimate’ of the fraction of the time the Sun was observed to be deduced. It is found that 52.7% of the days have recorded observations. There are additional 12 observers who provide general statements that no sunspots were observed during specific years or intervals despite diligent efforts. Taking these statements to mean, unrealistically, that every day during these intervals was observed, gives an ‘upper estimate’ of 98% of the days. If the general statements are relaxed by assuming that 100 ± 50 days per year were actually observed by these diligent observers, than our ‘best estimate’ is that 68%±7% of the days during the Maunder Minimum were observed. In short, this supports the view that the Maunder Minimum existed and was not an artifact of few observations. Some sunspots are probably still missed in modern compilations, but the existence of a prolonged sunspot minimum would not be threatened by their discovery in future research. Additional support for intense scrutiny of the Sun comes from a report of a white-light flare in 1705 and from the numerous reports of new sunspots entering the disk of the Sun.

Numerical study of electronic impact and radiation in sonoluminescence

NASA Astrophysics Data System (ADS)

Xu, Ning; Wang, Long; Hu, Xiwei

1998-02-01

A hydrodynamic simulation of pure argon single-bubble sonoluminescence including electron collisional ionization, recombination, and radiative energy loss has been performed. We find that near the moment that the bubble reaches its minimum radius the atoms inside a very thin layer around the origin of the bubble are strongly ionized, and the light emission occurs nearly simultaneously. Therefore we conclude that multiple ionization and recombination, which mainly occur in the thin layer of plasma, play a dramatically important role in the noble gas sonoluminescence. We also find that the temperature and the intensity of luminescence are not so high as those predicted by previous models, which consider only neutral gases.

Potential energy savings with exterior shades in large office buildings and the impact of discomfort glare

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoffmann, Sabine; Lee, Eleanor

Exterior shades are highly efficient for reducing solar load in commercial buildings. Their impact on net energy use depends on the annual energy balance of heating, cooling, fan and lighting energy. This paper discusses the overall energy use intensity of various external shading systems for a prototypical large office building split into the different types of energy use and for different orientations and window sizes. Lighting energy was calculated for a constant lighting power as well as for dimmed lighting fixtures (daylighting control). In Section 3, slat angles and solar cut-off angles were varied for fixed exterior slat shading systems.more » While the most light-blocking shades performed best for the case without daylighting controls, the optimum cut-off angle with daylighting controls was found to be 30 deg for the office building prototype used in Chicago and Houston. For large window-to-wall (WWR) ratios, window related annual energy use could be reduced by at least 70 % without daylighting control and by a minimum of 86 % with daylighting control in average over all orientations. The occurrence of discomfort glare was is considered in Section 4 of the paper, which looks at the performance of commercially available exterior shading systems when an interior shade is used in addition to the exterior shade during hours when occupants would experience discomfort glare. Glare control impacts overall energy use intensity significantly for exterior shades with high transmittance, especially when daylighting controls are used. In these cases, exterior shades are only beneficial for window-to-wall areas ≥ 45% in the hot Houston climate. For smaller windows and in a heating/cooling climate like Chicago, exterior shades can increase energy consumption« less

Low-cost, high-precision micro-lensed optical fiber providing deep-micrometer to deep-nanometer-level light focusing.

PubMed

Wen, Sy-Bor; Sundaram, Vijay M; McBride, Daniel; Yang, Yu

2016-04-15

A new type of micro-lensed optical fiber through stacking appropriate high-refractive microspheres at designed locations with respect to the cleaved end of an optical fiber is numerically and experimentally demonstrated. This new type of micro-lensed optical fiber can be precisely constructed with low cost and high speed. Deep micrometer-scale and submicrometer-scale far-field light spots can be achieved when the optical fibers are multimode and single mode, respectively. By placing an appropriate teardrop dielectric nanoscale scatterer at the far-field spot of this new type of micro-lensed optical fiber, a deep-nanometer near-field spot can also be generated with high intensity and minimum joule heating, which is valuable in high-speed, high-resolution, and high-power nanoscale detection compared with traditional near-field optical fibers containing a significant portion of metallic material.

Anomalous and Galactic Cosmic Ray Intensities at 1 AU During the Approach to the Cycle 24/25 Solar Minimum and Throughout the Last 20 Years

NASA Astrophysics Data System (ADS)

Leske, R. A.; Cummings, A. C.; Mewaldt, R. A.; Cohen, C.; Stone, E. C.; Wiedenbeck, M. E.

2017-12-01

Anomalous cosmic ray (ACR) intensities at 1 AU generally track galactic cosmic ray (GCR) intensities, but with differences between solar polarity cycles: at high rigidities, GCRs reach higher peak intensities during A<0 cycles, while ACRs have been higher at A>0 solar minima. At present, during the approach to an A>0 solar minimum, ACR oxygen above 8 MeV/nucleon as measured by the Advanced Composition Explorer (ACE) has already reached the peak intensities seen during the 2009 A<0 solar minimum, but is still 40% below the levels seen in 1997 during the last A>0 minimum. The GCR iron intensity at 300 MeV/nucleon, on the other hand, is presently comparable to that in 1997 but remains 10% below its record-setting 2009 value. Drift effects play an important role in the modulation of both ACRs and GCRs. Positively charged ions drift inward along the heliospheric current sheet (HCS) during A<0 cycles and their intensities are thus sensitive to the HCS tilt angle, which remained high for much of the last solar cycle. We have previously shown that both ACR and GCR intensities were significantly higher for a given HCS tilt angle during the 2000-2012 A<0 cycle than they were during the prior (1980-1990) A<0 cycle, and this trend appears to be continuing into the new A>0 cycle. But while GCR intensities in 2009 reached the highest levels recorded during the last 50 years, ACR intensities were only similar to those in the 1980s A<0 minimum. Factors such as a weaker interplanetary magnetic field, perhaps with a reduction in the ACR source strength or greater sensitivity of ACRs than GCRs to the HCS tilt angle, may account for the difference in their modulation behavior.We present 20 years of ACR and GCR intensity data acquired by ACE throughout two solar cycles, with emphasis on recent observations, and discuss possible reasons for the differences in the relative behavior of ACRs and GCRs in the different solar cycles.

Quantitative phase measurement for wafer-level optics

NASA Astrophysics Data System (ADS)

Qu, Weijuan; Wen, Yongfu; Wang, Zhaomin; Yang, Fang; Huang, Lei; Zuo, Chao

2015-07-01

Wafer-level-optics now is widely used in smart phone camera, mobile video conferencing or in medical equipment that require tiny cameras. Extracting quantitative phase information has received increased interest in order to quantify the quality of manufactured wafer-level-optics, detect defective devices before packaging, and provide feedback for manufacturing process control, all at the wafer-level for high-throughput microfabrication. We demonstrate two phase imaging methods, digital holographic microscopy (DHM) and Transport-of-Intensity Equation (TIE) to measure the phase of the wafer-level lenses. DHM is a laser-based interferometric method based on interference of two wavefronts. It can perform a phase measurement in a single shot. While a minimum of two measurements of the spatial intensity of the optical wave in closely spaced planes perpendicular to the direction of propagation are needed to do the direct phase retrieval by solving a second-order differential equation, i.e., with a non-iterative deterministic algorithm from intensity measurements using the Transport-of-Intensity Equation (TIE). But TIE is a non-interferometric method, thus can be applied to partial-coherence light. We demonstrated the capability and disability for the two phase measurement methods for wafer-level optics inspection.

Effects of light intensity on components and topographical structures of extracellular polysaccharides from the cyanobacteria Nostoc sp.

PubMed

Ge, Hongmei; Xia, Ling; Zhou, Xuping; Zhang, Delu; Hu, Chunxiang

2014-02-01

A study on the effects of light intensity (40 and 80 μE/m(2)/sec) on the components and topographical structures of extracellular polysaccharides (EPS) was carried out in cyanobacteria Nostoc sp.. EPS yield increased with light intensity. However, light intensity did not significantly affect the EPS fractions and monosaccharide composition. Higher light intensity generally resulted in higher protein content of EPS in similar fractions. The topographical structure of EPS, investigated by atomic force microscopy, appeared as spherical lumps, chains and networks. The long chains were observed at higher light intensity. Thus, light intensity affected the yield and nature of EPS.

Aberrations in stimulated emission depletion (STED) microscopy

NASA Astrophysics Data System (ADS)

Antonello, Jacopo; Burke, Daniel; Booth, Martin J.

2017-12-01

Like all methods of super-resolution microscopy, stimulated emission depletion (STED) microscopy can suffer from the effects of aberrations. The most important aspect of a STED microscope is that the depletion focus maintains a minimum, ideally zero, intensity point that is surrounded by a region of higher intensity. It follows that aberrations that cause a non-zero value of this minimum intensity are the most detrimental, as they inhibit fluorescence emission even at the centre of the depletion focus. We present analysis that elucidates the nature of these effects in terms of the different polarisation components at the focus for two-dimensional and three-dimensional STED resolution enhancement. It is found that only certain low-order aberration modes can affect the minimum intensity at the Gaussian focus. This has important consequences for the design of adaptive optics aberration correction systems.

Method for fabrication of cylindrical microlenses of selected shape

DOEpatents

Snyder, J.J.; Baer, T.M.

1992-01-14

The present invention provides a diffraction limited, high numerical aperture (fast) cylindrical microlens. The method for making the microlens is adaptable to produce a cylindrical lens that has almost any shape on its optical surfaces. The cylindrical lens may have a shape, such as elliptical or hyperbolic, designed to transform some particular given input light distribution into some desired output light distribution. In the method, the desired shape is first formed in a glass preform. Then, the preform is heated to the minimum drawing temperature and a fiber is drawn from it. The cross-sectional shape of the fiber bears a direct relation to the shape of the preform from which it was drawn. During the drawing process, the surfaces become optically smooth due to fire polishing. The present invention has many applications, such as integrated optics, optical detectors and laser diodes. The lens, when connected to a laser diode bar, can provide a high intensity source of laser radiation for pumping a high average power solid state laser. In integrated optics, a lens can be used to couple light into and out of apertures such as waveguides. The lens can also be used to collect light, and focus it on a detector. 11 figs.

Method for fabrication of cylindrical microlenses of selected shape

DOEpatents

Snyder, James J.; Baer, Thomas M.

1992-01-01

The present invention provides a diffraction limited, high numerical aperture (fast) cylindrical microlens. The method for making the microlens is adaptable to produce a cylindrical lens that has almost any shape on its optical surfaces. The cylindrical lens may have a shape, such as elliptical or hyperbolic, designed to transform some particular given input light distribution into some desired output light distribution. In the method, the desired shape is first formed in a glass preform. Then, the preform is heated to the minimum drawing temperature and a fiber is drawn from it. The cross-sectional shape of the fiber bears a direct relation to the shape of the preform from which it was drawn. During the drawing process, the surfaces become optically smooth due to fire polishing. The present invention has many applications, such as integrated optics, optical detectors and laser diodes. The lens, when connected to a laser diode bar, can provide a high intensity source of laser radiation for pumping a high average power solid state laser. In integrated optics, a lens can be used to couple light into and out of apertures such as waveguides. The lens can also be used to collect light, and focus it on a detector.

Increased physical activity improves sleep and mood outcomes in inactive people with insomnia: a randomized controlled trial.

PubMed

Hartescu, Iuliana; Morgan, Kevin; Stevinson, Clare D

2015-10-01

While high levels of activity and exercise training have been associated with improvements in sleep quality, minimum levels of activity likely to improve sleep outcomes have not been explored. A two-armed parallel randomized controlled trial (N=41; 30 females) was designed to assess whether increasing physical activity to the level recommended in public health guidelines can improve sleep quality among inactive adults meeting research diagnostic criteria for insomnia. The intervention consisted of a monitored program of ≥150 min of moderate- to vigorous-intensity physical activity per week, for 6 months. The principal end-point was the Insomnia Severity Index at 6 months post-baseline. Secondary outcomes included measures of mood, fatigue and daytime sleepiness. Activity and light exposure were monitored throughout the trial using accelerometry and actigraphy. At 6 months post-baseline, the physical activity group showed significantly reduced insomnia symptom severity (F(8,26) = 5.16, P = 0.03), with an average reduction of four points on the Insomnia Severity Index; and significantly reduced depression and anxiety scores (F(6,28) = 5.61, P = 0.02; and F(6,28) = 4.41, P = 0.05, respectively). All of the changes were independent of daily light exposure. Daytime fatigue showed no significant effect of the intervention (F(8,26) = 1.84, P = 0.18). Adherence and retention were high. Internationally recommended minimum levels of physical activity improve daytime and night-time symptoms of chronic insomnia independent of daily light exposure levels. © 2015 European Sleep Research Society.

Daytime light intensity affects seasonal timing via changes in the nocturnal melatonin levels

NASA Astrophysics Data System (ADS)

Kumar, Vinod; Rani, Sangeeta; Malik, Shalie; Trivedi, Amit K.; Schwabl, Ingrid; Helm, Barbara; Gwinner, Eberhard

2007-08-01

Daytime light intensity can affect the photoperiodic regulation of the reproductive cycle in birds. The actual way by which light intensity information is transduced is, however, unknown. We postulate that transduction of the light intensity information is mediated by changes in the pattern of melatonin secretion. This study, therefore, investigated the effects of high and low daytime light intensities on the daily melatonin rhythm of Afro-tropical stonechats ( Saxicola torquata axillaris) in which seasonal changes in daytime light intensity act as a zeitgeber of the circannual rhythms controlling annual reproduction and molt. Stonechats were subjected to light conditions simulated as closely as possible to native conditions near the equator. Photoperiod was held constant at 12.25 h of light and 11.75 h of darkness per day. At intervals of 2.5 to 3.5 weeks, daytime light intensity was changed from bright (12,000 lux at one and 2,000 lux at the other perch) to dim (1,600 lux at one and 250 lux at the other perch) and back to the original bright light. Daily plasma melatonin profiles showed that they were linked with changes in daytime light intensity: Nighttime peak and total nocturnal levels were altered when transitions between light conditions were made, and these changes were significant when light intensity was changed from dim to bright. We suggest that daytime light intensity could affect seasonal timing via changes in melatonin profiles.

Early Birds by Light at Night: Effects of Light Color and Intensity on Daily Activity Patterns in Blue Tits.

PubMed

de Jong, Maaike; Caro, Samuel P; Gienapp, Phillip; Spoelstra, Kamiel; Visser, Marcel E

2017-08-01

Artificial light at night disturbs the daily rhythms of many organisms. To what extent this disturbance depends on the intensity and spectral composition of light remain obscure. Here, we measured daily activity patterns of captive blue tits ( Cyanistes caeruleus) exposed to similar intensities of green, red, or white light at night. Birds advanced their onset of activity in the morning under all light colors but more under red and white light than under green light. Offset of activity was slightly delayed in all light colors. The total activity over a 24-h period did not change but birds moved a part of their daily activity into the night. Since the effect of red and white lights are comparable, we tested the influence of light intensity in a follow-up experiment, where we compared the activity of the birds under different intensities of green and white light only. While in the higher range of intensities, the effects of white and green light were comparable; at lower intensities, green light had a less disturbing effect as compared with white light on daily rhythms in blue tits. Our results show that the extent of this disturbance can be mitigated by modulating the spectral characteristics and intensity of outdoor lighting, which is now feasible through the use of LED lighting.

Intense X-ray and EUV light source

DOEpatents

Coleman, Joshua; Ekdahl, Carl; Oertel, John

2017-06-20

An intense X-ray or EUV light source may be driven by the Smith-Purcell effect. The intense light source may utilize intense electron beams and Bragg crystals. This may allow the intense light source to range from the extreme UV range up to the hard X-ray range.

14 CFR 23.1389 - Position light distribution and intensities.

Code of Federal Regulations, 2012 CFR

2012-01-01

... Equipment Lights § 23.1389 Position light distribution and intensities. (a) General. The intensities prescribed in this section must be provided by new equipment with each light cover and color filter in place... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Position light distribution and intensities...

14 CFR 23.1389 - Position light distribution and intensities.

Code of Federal Regulations, 2013 CFR

2013-01-01

... Equipment Lights § 23.1389 Position light distribution and intensities. (a) General. The intensities prescribed in this section must be provided by new equipment with each light cover and color filter in place... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Position light distribution and intensities...

14 CFR 23.1389 - Position light distribution and intensities.

Code of Federal Regulations, 2014 CFR

2014-01-01

... Equipment Lights § 23.1389 Position light distribution and intensities. (a) General. The intensities prescribed in this section must be provided by new equipment with each light cover and color filter in place... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Position light distribution and intensities...

Nonlinear tuning techniques of plasmonic nano-filters

NASA Astrophysics Data System (ADS)

Kotb, Rehab; Ismail, Yehea; Swillam, Mohamed A.

2015-02-01

In this paper, a fitting model to the propagation constant and the losses of Metal-Insulator-Metal (MIM) plasmonic waveguide is proposed. Using this model, the modal characteristics of MIM plasmonic waveguide can be solved directly without solving Maxwell's equations from scratch. As a consequence, the simulation time and the computational cost that are needed to predict the response of different plasmonic structures can be reduced significantly. This fitting model is used to develop a closed form model that describes the behavior of a plasmonic nano-filter. Easy and accurate mechanisms to tune the filter are investigated and analyzed. The filter tunability is based on using a nonlinear dielectric material with Pockels or Kerr effect. The tunability is achieved by applying an external voltage or through controlling the input light intensity. The proposed nano-filter supports both red and blue shift in the resonance response depending on the type of the used non-linear material. A new approach to control the input light intensity by applying an external voltage to a previous stage is investigated. Therefore, the filter tunability to a stage that has Kerr material can be achieved by applying voltage to a previous stage that has Pockels material. Using this method, the Kerr effect can be achieved electrically instead of varying the intensity of the input source. This technique enhances the ability of the device integration for on-chip applications. Tuning the resonance wavelength with high accuracy, minimum insertion loss and high quality factor is obtained using these approaches.

Critical fluid light scattering

NASA Technical Reports Server (NTRS)

Gammon, Robert W.

1988-01-01

The objective is to measure the decay rates of critical density fluctuations in a simple fluid (xenon) very near its liquid-vapor critical point using laser light scattering and photon correlation spectroscopy. Such experiments were severely limited on Earth by the presence of gravity which causes large density gradients in the sample when the compressibility diverges approaching the critical point. The goal is to measure fluctuation decay rates at least two decades closer to the critical point than is possible on earth, with a resolution of 3 microK. This will require loading the sample to 0.1 percent of the critical density and taking data as close as 100 microK to the critical temperature. The minimum mission time of 100 hours will allow a complete range of temperature points to be covered, limited by the thermal response of the sample. Other technical problems have to be addressed such as multiple scattering and the effect of wetting layers. The experiment entails measurement of the scattering intensity fluctuation decay rate at two angles for each temperature and simultaneously recording the scattering intensities and sample turbidity (from the transmission). The analyzed intensity and turbidity data gives the correlation length at each temperature and locates the critical temperature. The fluctuation decay rate data from these measurements will provide a severe test of the generalized hydrodynamic theories of transport coefficients in the critical regions. When compared to equivalent data from binary liquid critical mixtures they will test the universality of critical dynamics.

Biophotonic perception on Desmodesmus sp. VIT growth, lipid and carbohydrate content.

PubMed

Sriram, Srinivasan; Seenivasan, Ramasubbu

2015-12-01

Constant and fluctuating light intensity significantly affects the growth and biochemical composition of microalgae and it is essential to identify suitable illumination conditions for commercial microalgae biofuel production. In the present study, effects of light intensities, light:dark cycles, incremental light intensity strategies and fluctuating light intensities simulating different sky conditions in indoor photobioreactor on Desmodesmus sp. VIT growth, lipid and carbohydrate content were analyzed in batch culture. The results revealed that Desmodesmus sp. VIT obtained maximum lipid content (22.5%) and biomass production (1.033 g/L) under incremental light intensity strategy. The highest carbohydrate content of 25.4% was observed under constant light intensity of 16,000 lx and 16:08 h light:dark cycle. The maximum biomass productivity of Desmodesmus sp. VIT (53.38 mg/L/d) was occurred under fluctuating light intensity simulating intermediate overcast sky condition. Copyright © 2015 Elsevier Ltd. All rights reserved.

Physiological and biochemical responses of Prorocentrum minimum to high light stress

NASA Astrophysics Data System (ADS)

Park, So Yun; Choi, Eun Seok; Hwang, Jinik; Kim, Donggiun; Ryu, Tae Kwon; Lee, Taek-Kyun

2009-12-01

Prorocentrum minimum is a common bloomforming photosynthetic dinoflagellate found along the southern coast of Korea. To investigate the adaptive responses of P. minimum to high light stress, we measured growth rate, and generation of reactive oxidative species (ROS), superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA) in cultures exposed to normal (NL) and high light levels (HL). The results showed that HL (800 μmol m-2 s-1) inhibited growth of P. minimum, with maximal inhibition after 7-9 days. HL also increased the amount of ROS and MDA, suggesting that HL stress leads to oxidative damage and lipid peroxidation in this species. Under HL, we first detected superoxide on day 4 and H2O2 on day 5. We also detected SOD activity on day 5 and CAT activity on day 6. The level of lipid peroxidation, an indicator of cell death, was high on day 8. Addition of diphenyleneiodonium (DPI), an NAD(P)H inhibitor, decreased the levels of superoxide generation and lipid peroxidation. Our results indicate that the production of ROS which results from HL stress in P. minimum also induces antioxidative enzymes that counteract oxidative damage and allow P. minimum to survive.

Intensity output and effectiveness of light curing units in dental offices.

PubMed

Omidi, Baharan-Ranjbar; Gosili, Armin; Jaber-Ansari, Mona; Mahdkhah, Ailin

2018-06-01

The aims of the study were measuring the light intensity of light curing units used in Qazvin's dental offices, determining the relationship between the clinical age of these units and their light intensity, and identifying the reasons for repairing them. In this cross-sectional study, the output intensity of 95 light curing devices was evaluated using a radiometer. The average output intensity was divided up into four categories (less than 200, 200-299, 300-500, and more than 500 mW/cm2). In addition, a questionnaire was designed to obtain information mainly about the type, clinical age, and frequency of maintenance of the units and the reasons for fixing them. Data were analyzed using Kolmogorov-Smirnov, chi-squared, and t-tests ( p < 0.05) on SPSS 24. A total of 95 light curing units were examined, with 61 (64.2%) of them being of the LED type and 34 (35.8%) of the QTH type. While average light intensity in LED units was significantly higher than in QTH devices, the two device types were not significantly different regarding desirable light intensity (i.e., ≥ 300 mw/cm2). A negative correlation was observed between clinical age and light intensity. In addition, bulb replacement in QTH devices was over three times as much as in LED units. Also, repairing QTHs was more than twice as much frequent as fixing LEDs. The most common reason for repair was the breakage of the tip of the device. The light intensity of LED units is significantly higher than that of QTH devices, and the frequency of repairing in QTHs was significantly more than in LEDs. Furthermore, light intensity decreases with aging, and dentists should regularly monitor the conditions of light units. Key words: Light curing unit, radiometer, light intensity, dental equipment, dental offices.

Photometry of AM Herculis - A slow optical pulsar

NASA Technical Reports Server (NTRS)

Priedhorsky, W. C.; Krzeminski, W.

1978-01-01

Multicolor photometry of the X-ray binary AM Her suggests that the red component of the optical flux is closely related to the source of optical circular polarization in the system. It is concluded from the periodic modulation of flux in the U through R bands, which is particularly well-defined when plotted as color curves, that the primary and secondary minima are neither eclipses by a secondary star nor eclipses by a hot spot. It is suggested that the primary minimum in the visual light curve is the eclipse of a region of intense optical emission in the magnetic field near the surface of a degenerate dwarf by that dwarf itself.

Teaching the Minimum Wage in Econ 101 in Light of the New Economics of the Minimum Wage.

ERIC Educational Resources Information Center

Krueger, Alan B.

2001-01-01

Argues that the recent controversy over the effect of the minimum wage on employment offers an opportunity for teaching introductory economics. Examines eight textbooks to determine topic coverage but finds little consensus. Describes how minimum wage effects should be taught. (RLH)

Infrared absorption of trans-1-chloromethylallyl and trans-1-methylallyl radicals produced in photochemical reactions of trans-1,3-butadiene and Cl2 in solid para-hydrogen.

PubMed

Bahou, Mohammed; Wu, Jen-Yu; Tanaka, Keiichi; Lee, Yuan-Pern

2012-08-28

The reactions of chlorine and hydrogen atoms with trans-1,3-butadiene in solid para-hydrogen (p-H(2)) were investigated with infrared (IR) absorption spectra. When a p-H(2) matrix containing Cl(2) and trans-1,3-butadiene was irradiated with ultraviolet light at 365 nm, intense lines at 650.3, 809.0, 962.2, 1240.6 cm(-1), and several weaker ones due to the trans-1-chloromethylallyl radical, ●(CH(2)CHCH)CH(2)Cl, appeared. Observed wavenumbers and relative intensities agree with the anharmonic vibrational wavenumbers and IR intensities predicted with the B3PW91/6-311++g(2d, 2p) method. That the Cl atom adds primarily to the terminal carbon atom of trans-1,3-butadiene is in agreement with the path of minimum energy predicted theoretically, but in contrast to the reaction of Cl + propene in solid p-H(2) [J. Amicangelo and Y.-P. Lee, J. Phys. Chem. Lett. 1, 2956 (2010)] in which the addition of Cl to the central C atom is favored, likely through steric effects in a p-H(2) matrix. A second set of lines, intense at 781.6, 957.9, 1433.6, 2968.8, 3023.5, 3107.3 cm(-1), were observed when the UV-irradiated Cl(2)/trans-1,3-butadiene/p-H(2) matrix was further irradiated with IR light from a SiC source. These lines are assigned to the trans-1-methylallyl radical, ●(CH(2)CHCH)CH(3), produced from reaction of 1,3-butadiene with a H atom resulted from the reaction of Cl atoms with solid p-H(2) exposed to IR radiation.

'In a dark place, we find ourselves': light intensity in critical care units.

PubMed

Durrington, Hannah J; Clark, Richard; Greer, Ruari; Martial, Franck P; Blaikley, John; Dark, Paul; Lucas, Robert J; Ray, David W

2017-12-01

Intensive care units provide specialised care for critically ill patients around the clock. However, intensive care unit patients have disrupted circadian rhythms. Furthermore, disrupted circadian rhythms are associated with worse outcome. As light is the most powerful 're-setter' of circadian rhythm, we measured light intensity on intensive care unit. Light intensity was low compared to daylight during the 'day'; frequent bright light interruptions occurred over 'night'. These findings are predicted to disrupt circadian rhythms and impair entrainment to external time. Bright lighting during daytime and black out masks at night might help maintain biological rhythms in critically ill patients and improve clinical outcomes.

Application of growth-phase based light-feeding strategies to simultaneously enhance Chlorella vulgaris growth and lipid accumulation.

PubMed

Sun, Yahui; Liao, Qiang; Huang, Yun; Xia, Ao; Fu, Qian; Zhu, Xun; Fu, Jingwei; Li, Jun

2018-05-01

Considering the variations of optimal light intensity required by microalgae cells along with growth phases, growth-phase light-feeding strategies were proposed and verified in this paper, aiming at boosting microalgae lipid productivity from the perspective of light conditions optimization. Experimental results demonstrate that under an identical time-averaged light intensity, the light-feeding strategies characterized by stepwise incremental light intensities showed a positive effect on biomass and lipid accumulation. The lipid productivity (235.49 mg L -1  d -1 ) attained under light-feeding strategy V (time-averaged light intensity: 225 μmol m -2  s -1 ) was 52.38% higher over that obtained under a constant light intensity of 225 μmol m -2  s -1 . Subsequently, based on light-feeding strategy V, microalgae lipid productivity was further elevated to 312.92 mg L -1  d -1 employing a two-stage based light-feeding strategy V 560 (time-averaged light intensity: 360 μmol m -2  s -1 ), which was 79.63% higher relative to that achieved under a constant light intensity of 360 μmol m -2  s -1 . Copyright © 2018 Elsevier Ltd. All rights reserved.

The ultraviolet variations of iota Cas

NASA Technical Reports Server (NTRS)

Molnar, M. R.; Mallama, A. D.; Soskey, D. G.; Holm, A. V.

1976-01-01

The Ap variable star iota Cas was observed with the photometers on OAO-2 covering the spectral range 1430-4250 A. The ultraviolet light curves show a double wave with primary minimum and maximum at phase ? 0.00 and 0.35, respectively. Secondary minimum light is at phase ? 0.65 with secondary maximum at phase ? 0.85. The light curves longward of 3150 A vary in opposition to those shortward of this 'null region'. Ground-based coude spectra show that the Fe II and Cr II line strengths have a double-wave variation such that maximum strength occurs at minimum ultraviolet light. We suggest that the strong ultraviolet opacities due to photoionization and line blanketing by these metals may cause the observed photometric variations. We have also constructed an oblique-rotator model which shows iron and chromium lying in a great circle band rather than in circular spots.

On a thermonuclear origin for the 1980-81 deep light minimum of the symbiotic nova PU Vul

NASA Technical Reports Server (NTRS)

Sion, Edward M.

1993-01-01

The puzzling 1980-81 deep light minimum of the symbiotic nova PU Vul is discussed in terms of a sequence of quasi-static evolutionary models of a hot, 0.5 solar mass white dwarf accreting H-rich matter at a rate 1 x 10 exp -8 solar mass/yr. On the basis of the morphological behavior of the models, it is suggested that the deep light minimum of PU Vul could have been the result of two successive, closely spaced, hydrogen shell flashes on an accreting white dwarf whose core thermal structure and accreted H-rich envelope was not in a long-term thermal 'cycle-averaged' steady state with the rate of accretion.

Battery Charge Affects the Stability of Light Intensity from Light-emitting Diode Light-curing Units.

PubMed

Tongtaksin, A; Leevailoj, C

This study investigated the influence of battery charge levels on the stability of light-emitting diode (LED) curing-light intensity by measuring the intensity from fully charged through fully discharged batteries. The microhardness of resin composites polymerized by the light-curing units at various battery charge levels was measured. The light intensities of seven fully charged battery LED light-curing units-1) LY-A180, 2) Bluephase, 3) Woodpecker, 4) Demi Plus, 5) Saab II, 6) Elipar S10, and 7) MiniLED-were measured with a radiometer (Kerr) after every 10 uses (20 seconds per use) until the battery was discharged. Ten 2-mm-thick cylindrical specimens of A3 shade nanofilled resin composite (PREMISE, Kerr) were prepared per LED light-curing unit group. Each specimen was irradiated by the fully charged light-curing unit for 20 seconds. The LED light-curing units were then used until the battery charge fell to 50%. Specimens were prepared again as described above. This was repeated again when the light-curing units' battery charge fell to 25% and when the light intensity had decreased to 400 mW/cm 2 . The top/bottom surface Knoop hardness ratios of the specimens were determined. The microhardness data were analyzed by one-way analysis of variance with Tukey test at a significance level of 0.05. The Pearson correlation coefficient was used to determine significant correlations between surface hardness and light intensity. We found that the light intensities of the Bluephase, Demi Plus, and Elipar S10 units were stable. The intensity of the MiniLED unit decreased slightly; however, it remained above 400 mW/cm 2 . In contrast, the intensities of the LY-A180, Woodpecker, and Saab II units decreased below 400 mW/cm 2 . There was also a significant decrease in the surface microhardnesses of the resin composite specimens treated with MiniLED, LY-A180, Woodpecker, and Saab II. In conclusion, the light intensity of several LED light-curing units decreased as the battery was discharged, with a coincident reduction in the units' ability to polymerize resin composite. Therefore, the intensity of an LED light-curing unit should be evaluated during the life of its battery charge to ensure that sufficient light intensity is being generated.

Heat transfer assembly for a fluorescent lamp and fixture

DOEpatents

Siminovitch, Michael J.; Rubenstein, Francis M.; Whitman, Richard E.

1992-01-01

In a lighting fixture including a lamp and a housing, a heat transfer structure is disclosed for reducing the minimum lamp wall temperature of a fluorescent light bulb. The heat transfer structure, constructed of thermally conductive material, extends from inside the housing to outside the housing, transferring heat energy generated from a fluorescent light bulb to outside the housing where the heat energy is dissipated to the ambient air outside the housing. Also disclosed is a method for reducing minimum lamp wall temperatures. Further disclosed is an improved lighting fixture including a lamp, a housing and the aforementioned heat transfer structure.

Design considerations for highly effective fluorescence excitation and detection optical systems for molecular diagnostics

NASA Astrophysics Data System (ADS)

Kasper, Axel; Van Hille, Herbert; Kuk, Sola

2018-02-01

Modern instruments for molecular diagnostics are continuously optimized for diagnostic accuracy, versatility and throughput. The latest progress in LED technology together with tailored optics solutions allows developing highly efficient photonics engines perfectly adapted to the sample under test. Super-bright chip-on-board LED light sources are a key component for such instruments providing maximum luminous intensities in a multitude of narrow spectral bands. In particular the combination of white LEDs with other narrow band LEDs allows achieving optimum efficiency outperforming traditional Xenon light sources in terms of energy consumption, heat dissipation in the system, and switching time between spectral channels. Maximum sensitivity of the diagnostic system can only be achieved with an optimized optics system for the illumination and imaging of the sample. The illumination beam path must be designed for optimum homogeneity across the field while precisely limiting the angular distribution of the excitation light. This is a necessity for avoiding spill-over to the detection beam path and guaranteeing the efficiency of the spectral filtering. The imaging optics must combine high spatial resolution, high light collection efficiency and optimized suppression of excitation light for good signal-to-noise ratio. In order to achieve minimum cross-talk between individual wells in the sample, the optics design must also consider the generation of stray light and the formation of ghost images. We discuss what parameters and limitations have to be considered in an integrated system design approach covering the full path from the light source to the detector.

Light intensity modulates corneal power and refraction in the chick eye exposed to continuous light.

PubMed

Cohen, Yuval; Belkin, Michael; Yehezkel, Oren; Avni, Isaac; Polat, Uri

2008-09-01

Continuous exposure of chicks to light was shown to result in severe hyperopia, accompanied by anterior segment changes, such as severe corneal flattening. Since rearing chicks in complete darkness results only in mild hyperopia and minor changes in corneal curvature, we hypothesized that light intensity may play a role in the development of refractive changes under continuous light illumination. To test this hypothesis, we examined the effects of rearing chicks under various continuous light intensities. More specifically, we investigated the refractive parameters of the chicks' eyes, and avoided light cycling effects on ocular development. To this end, thirty-eight chicks were reared under 24-h incandescent illumination, at three different light intensities: 10,000 lux (n=13), 500 lux (n=12), and 50 lux (n=13). Their eyes underwent repeated retinoscopy, keratometry, and ultrasound biometry, as well as caliper measurements of enucleated eyes. Both refraction and corneal refractive power were found to be correlated with light intensity. On day 90 after hatching, exposure to light intensities of 10,000, 500, and 50 lux resulted in hyperopia of +11.97+/-3.7 (mean+/-SD) +7.9+/-4.08 and +0.63+/-3.61 diopters (D), respectively. Under those intensities, corneal refractive power was 46.10+/-3.62, 49.72+/-4.16, and 56.88+/-4.92D, respectively. Axial length did not differ significantly among the groups. The vitreous chamber was significantly deeper in the high than in the low-intensity groups. Thus, during the early life of chicks exposed to continuous lighting, light intensity affects the vitreous chamber depth as well as the anterior segment parameters, most notably the cornea. The higher the intensity, the more severe was the corneal flattening observed and the hyperopia that developed, whereas continuous illumination at low intensities resulted in emmetropia. Thus, light intensity is an important factor that should be taken into account when studying refractive development.

Light Absorptive Properties of Articular Cartilage, ECM Molecules, Synovial Fluid, and Photoinitiators as Potential Barriers to Light-Initiated Polymer Scaffolding Procedures.

PubMed

Finch, Anthony J; Benson, Jamie M; Donnelly, Patrick E; Torzilli, Peter A

2017-06-01

Objective Many in vivo procedures to repair chondral defects use ultraviolet (UV)-photoinitiated in situ polymerization within the cartilage matrix. Chemical species that absorb UV light might reduce the effectiveness of these procedures by acting as light absorption barriers. This study evaluated whether any of the individual native biochemical components in cartilage and synovial fluid interfered with the absorption of light by common scaffolding photosensitizers. Materials UV-visible spectroscopy was performed on each major component of cartilage in solution, on bovine synovial fluid, and on four photosensitizers, riboflavin, Irgacure 2959, quinine, and riboflavin-5'-phosphate. Molar extinction and absorption coefficients were calculated at wavelengths of maximum absorbance and 365 nm. Intact articular cartilage was also examined. Results The individual major biochemical components of cartilage, Irgacure 2959, and quinine did not exhibit a significant absorption at 365 nm. Riboflavin and riboflavin-5'-phosphate were more effectual light absorbers at 365 nm, compared with the individual native species. Intact cartilage absorbed a significantly greater amount of UV light in comparison with the native species. Conclusion Our results indicate that none of the individual native species in cartilage will interfere with the absorption of UV light at 365 nm by these commonly used photoinitiators. Intact cartilage slices exhibited significant light absorption at 365 nm, while also having distinct absorbance peaks at wavelengths less than 300 nm. Determining the UV absorptive properties of the biomolecules native to articular cartilage and synovial fluid will aid in optimizing scaffolding procedures to ensure sufficient scaffold polymerization at a minimum UV intensity.

Dependency between light intensity and refractive development under light-dark cycles.

PubMed

Cohen, Yuval; Belkin, Michael; Yehezkel, Oren; Solomon, Arieh S; Polat, Uri

2011-01-01

The emmetropization process involves fine-tuning the refractive state by altering the refractive components toward zero refraction. In this study, we provided light-dark cycle conditions at several intensities and examined the effect of light intensity on the progression of chicks' emmetropization. Chicks under high-, medium-, and low-light intensities (10,000, 500, and 50 lux, respectively) were followed for 90 days by retinoscopy, keratometry, as well as ultrasound measurements. Emmetropization was reached from days 30-50 and from days 50-60 for the low- and medium-intensity groups, respectively. On day 90, most chicks in the low-intensity group were myopic, with a mean refraction of -2.41D (95% confidence interval (CI) -2.9 to -1.8D), whereas no chicks in the high-intensity group developed myopia, but they exhibited a stable mean hyperopia of +1.1D. The medium-intensity group had a mean refraction of +0.03D. The low-intensity group had a deeper vitreous chamber depth and a longer axial length compared with the high-intensity group, and shifted refraction to the myopic side. The low-intensity group had a flatter corneal curvature, a deeper anterior chamber, and a thinner lens compared with the high-intensity group, and shifted refraction to the hyperopic side. In all groups the corneal power was correlated with the three examined levels of log light intensity for all examined times (e.g., day 20 r = 0.6 P < 0.0001, day 90 r = 0.56 P < 0.0001). Thus, under light-dark cycles, light intensity is an environmental factor that modulates the process of emmetropization, and the low intensity of ambient light is a risk factor for developing myopia. Copyright © 2010 Elsevier Ltd. All rights reserved.

Stress Intensity Factors of Semi-Circular Bend Specimens with Straight-Through and Chevron Notches

NASA Astrophysics Data System (ADS)

Ayatollahi, M. R.; Mahdavi, E.; Alborzi, M. J.; Obara, Y.

2016-04-01

Semi-circular bend specimen is one of the useful test specimens for determining fracture toughness of rock and geo-materials. Generally, in rock test specimens, initial cracks are produced in two shapes: straight-edge cracks and chevron notches. In this study, the minimum dimensionless stress intensity factors of semi-circular bend specimen (SCB) with straight-through and chevron notches are calculated. First, using finite element analysis, a suitable relation for the dimensionless stress intensity factor of SCB with straight-through crack is presented based on the normalized crack length and half-distance between supports. For evaluating the validity and accuracy of this relation, the obtained results are then compared with numerical and experimental results reported in the literature. Subsequently, by performing some experiments and also finite element analysis of the SCB specimen with chevron notch, the minimum dimensionless stress intensity factor of this specimen is obtained. Using the new equation for the dimensionless stress intensity factor of SCB with straight-through crack and an analytical method, i.e., Bluhm's slice synthesis method, the minimum (critical) dimensionless stress intensity factor of chevron notched semi-circular bend specimens is calculated. Good agreement is observed between the results of two mentioned methods.

Ectoparasites of a population of urban gray squirrels in northern Florida.

PubMed

Wilson, N A; Telford, S R; Forrester, D J

1991-05-01

Ectoparasites infesting a population of urban gray squirrels (Sciurus carolinensis Gmelin) in northern Florida were collected monthly during 1974. Eleven species were identified: one flea (Orchopeas howardi (Baker], three suckling lice (Enderleinellus longiceps Kellogg & Ferris, Hoplopleura sciuricola Ferris, and Neohaematopinus sciuri Jancke), one tick (Dermacentor variabilis Say), two mesostigmatid (gamasid) mites (Androlaelaps casalis (Berlese) and A. fahrenholzi (Berlese], and four chiggers (Eutrombicula alfreddugesi (Oudemans), E. splendens (Ewing), Leptotrombidium peromysci Vercammen-Grandjean & Langston, and Parasecia gurneyi (Ewing]. The flea and three suckling lice represent core species of ectoparasites for the gray squirrel; the remainder are probably satellite species. Only E. longiceps varied significantly in prevalence or intensity of infestation among host age groups; subadult squirrels had higher intensities than adults. Peak prevalence of O. howardi occurred in January and attained maximum intensity in March, whereas both prevalance and intensity were minimum in August. Prevalence of H. sciuricola was maximum in November and remained at similar levels through June. It then declined significantly to its minimum in September-October. Intensity of infestation, however, was greatest in August, September, and January. Maximum prevalence of N. sciuri occurred from January to March and was minimum in September; intensity of infestation reached maxima in January, June, and August.

The Impact of Environmental Light Intensity on Experimental Tumor Growth.

PubMed

Suckow, Mark A; Wolter, William R; Duffield, Giles E

2017-09-01

Cancer research requires for consistent models that minimize environmental variables. Within the typical laboratory animal housing facility, animals may be exposed to varying intensities of light as a result of cage type, cage position, light source, and other factors; however, studies evaluating the differential effect of light intensity during the light phase on tumor growth are lacking. The effect of cage face light intensity, as determined by cage rack position was evaluated with two tumor models using the C57Bl/6NHsd mouse and transplantable B16F10 melanoma cells or Lewis lung carcinoma (LLC) cells. Animals were housed in individually-ventilated cages placed at the top, middle, or bottom of the rack in a diagonal pattern so that the top cage was closest to the ceiling light source, and cage face light intensity was measured. Following a two-week acclimation period at the assigned cage position, animals were subcutaneously administered either 1.3×10 6 B16F10 melanoma cells or 2.5×10 5 Lewis lung carcinoma cells. Weights of excised tumors were measured following euthanasia 18 days (melanoma) or 21 days (LCC) after tumor cell administration. Cage face light intensity was significantly different depending on the location of the cage, with cages closest to the light source have the greatest intensity. Mean tumor weights were significantly less (p<0.001 for melanoma; p≤0.01 for LCC) in middle light intensity mice compared to high and low light intensity mice. The environmental light intensity to which experimental animals are exposed may vary markedly with cage location and can significantly influence experimental tumor growth, thus supporting the idea that light intensity should be controlled as an experimental variable for animals used in cancer research. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

Method for non-destructive evaluation of ceramic coatings

DOEpatents

Peterson, Kristen A.; Rosen, Elias P.; Jordan, Eric H.; Shahbazmohamadi, Sina; Vakhtin, Andrei B.

2016-11-08

A method for evaluating the condition of a ceramic coating deposited on a substrate comprising illuminating the ceramic coating with light, measuring the intensity of light returned from the ceramic coating as function of depth in the coating and transverse position on the coating, and analyzing the measured light intensities to obtain one or more of intensity of the light returned from the exposed coating surface relative to the intensity of light returned from the coating/substrate interface, intensity of the light returned from the coating/substrate interface relative to the intensity of light returned from the bulk of the ceramic coating, determination of roughness at the exposed surface of the ceramic coating, and determination of roughness of the interface between the ceramic coating and underlying bond coat or substrate.

Using a laser source to measure the refractive index of glass beads and Debye theory analysis.

PubMed

Li, Shui-Yan; Qin, Shuang; Li, Da-Hai; Wang, Qiong-Hua

2015-11-20

Using a monochromatic laser beam to illuminate a homogeneous glass bead, some rainbows will appear around it. This paper concentrates on the study of the scattering intensity distribution and the method of measuring the refractive index for glass beads based on the Debye theory. It is found that the first rainbow due to the scattering superposition of backward light of the low-refractive-index glass beads can be explained approximately with the diffraction, the external reflection plus the one internal reflection, while the second rainbow of high-refractive-index glass beads is due to the contribution from the diffraction, the external reflection, the direct transmission, and the two internal reflections. The scattering intensity distribution is affected by the refractive index, the radius of the glass bead, and the incident beam width. The effects of the refractive index and the glass bead size on the first and second minimum deviation angle position are analyzed in this paper. The results of the measurements agree very well with the specifications.

Optimized two-frequency phase-measuring-profilometry light-sensor temporal-noise sensitivity.

PubMed

Li, Jielin; Hassebrook, Laurence G; Guan, Chun

2003-01-01

Temporal frame-to-frame noise in multipattern structured light projection can significantly corrupt depth measurement repeatability. We present a rigorous stochastic analysis of phase-measuring-profilometry temporal noise as a function of the pattern parameters and the reconstruction coefficients. The analysis is used to optimize the two-frequency phase measurement technique. In phase-measuring profilometry, a sequence of phase-shifted sine-wave patterns is projected onto a surface. In two-frequency phase measurement, two sets of pattern sequences are used. The first, low-frequency set establishes a nonambiguous depth estimate, and the second, high-frequency set is unwrapped, based on the low-frequency estimate, to obtain an accurate depth estimate. If the second frequency is too low, then depth error is caused directly by temporal noise in the phase measurement. If the second frequency is too high, temporal noise triggers ambiguous unwrapping, resulting in depth measurement error. We present a solution for finding the second frequency, where intensity noise variance is at its minimum.

The Lactate Minimum Test: Concept, Methodological Aspects and Insights for Future Investigations in Human and Animal Models

PubMed Central

Messias, Leonardo H. D.; Gobatto, Claudio A.; Beck, Wladimir R.; Manchado-Gobatto, Fúlvia B.

2017-01-01

In 1993, Uwe Tegtbur proposed a useful physiological protocol named the lactate minimum test (LMT). This test consists of three distinct phases. Firstly, subjects must perform high intensity efforts to induce hyperlactatemia (phase 1). Subsequently, 8 min of recovery are allowed for transposition of lactate from myocytes (for instance) to the bloodstream (phase 2). Right after the recovery, subjects are submitted to an incremental test until exhaustion (phase 3). The blood lactate concentration is expected to fall during the first stages of the incremental test and as the intensity increases in subsequent stages, to rise again forming a “U” shaped blood lactate kinetic. The minimum point of this curve, named the lactate minimum intensity (LMI), provides an estimation of the intensity that represents the balance between the appearance and clearance of arterial blood lactate, known as the maximal lactate steady state intensity (iMLSS). Furthermore, in addition to the iMLSS estimation, studies have also determined anaerobic parameters (e.g., peak, mean, and minimum force/power) during phase 1 and also the maximum oxygen consumption in phase 3; therefore, the LMT is considered a robust physiological protocol. Although, encouraging reports have been published in both human and animal models, there are still some controversies regarding three main factors: (1) the influence of methodological aspects on the LMT parameters; (2) LMT effectiveness for monitoring training effects; and (3) the LMI as a valid iMLSS estimator. Therefore, the aim of this review is to provide a balanced discussion between scientific evidence of the aforementioned issues, and insights for future investigations are suggested. In summary, further analyses is necessary to determine whether these factors are worthy, since the LMT is relevant in several contexts of health sciences. PMID:28642717

Effect of Endurance Training on The Lactate and Glucose Minimum Intensities

PubMed Central

Junior, Pedro B.; de Andrade, Vitor L.; Campos, Eduardo Z.; Kalva-Filho, Carlos A.; Zagatto, Alessandro M.; de Araújo, Gustavo G.; Papoti, Marcelo

2018-01-01

Due to the controversy about the sensitive of lactate minimum intensity (LMI) to training and the need to develop other tool for aerobic fitness evaluation, the purpose of this study was to analyze the sensitivity of glucose minimum intensity (GMI) and LMI to endurance training. Eight trained male cyclists (21.4 ± 1.9 years, 67.6 ± 7.5 kg and 1.72 ± 0.10 m) were evaluated twice, before and after 12 weeks of training. GMI and LMI were calculated, respectively, by the lowest blood glucose and lactate values attained during an incremental test performed after a hyperlactemia induction, and VO2max was determined during standard incremental effort. The training was prescribed in three different zones and controlled by heart rate (HR). The training distribution was equivalent to 59.7%, 25.0% and 15.3% below, at and above anaerobic threshold HR respectively. The anaerobic threshold evaluated by GMI and LMI improvement 9.89 ± 4.35% and 10.28 ± 9.89 respectively, after training, but the VO2max 2.52 ± 1.81%. No differences were found between GMI and LMI in pre (218.2 ± 22.1 vs 215.0 ± 18.6 W) and post (240.6 ± 22.9 vs 237.5 ± 18.8 W) training situations. LMI and GMI were sensitive to 12-week aerobic training in cyclist; thus, both protocols can be used to assess aerobic adaptation, athletes diagnostic and prescribe training. Key points The lactate and glucose minimum intensities (GMI) can be used for monitoring training effects on cyclists Although both GMI and lactate minimum intensities are important index of aerobic fitness, they cannot be used to determine aerobic fitness. The polarized training was effective for improvements of maximal oxygen uptake on trained cyclists. PMID:29535585

SPHEREx: Understanding the Origin and Evolution of Galaxies Through the Extragalactic Background Light

NASA Astrophysics Data System (ADS)

Zemcov, Michael; SPHEREx Science Team

2018-01-01

The near IR extragalactic background light (EBL) encodes the integrated light production over cosmic history, so traces the total emission from all galaxies along the line of sight up to the ancient first-light objects responsible for the epoch of reionization (EOR). The EBL can be constrained through measurements of anisotropies, taking advantage of the fact that extragalactic populations produce fluctuations with distinct spatial and spectral characteristics from local foregrounds. In particular, EBL anisotropies trace the underlying clustering of faint emission sources, such as stars, galaxies and accreting black holes present during the EOR, dwarf galaxies, and intra-halo light (IHL), all of which are components not readily detected in point source surveys. The fluctuation amplitude observed independently by a number of recent measurements exceeds that expected from the large-scale clustering of known galaxy populations, indicating the presence of a large integrated brightness from these faint and diffuse components. Improved large-area measurements covering the entire near-IR are required to constrain the possible models for the history of emission from stars back to the EOR.SPHEREx brings new capabilities to EBL fluctuation measurements, employing 96 spectral channels covering 0.75 to 5 microns with spectral resolving power R = 41 to 135 that enable SPHEREx to carry out a multi-frequency separation of the integrated light from galaxies, IHL, and EOR components using the rich auto- and cross-correlation information available from two 45 square degree surveys of the ecliptic poles. SPHEREx is an ideal intensity mapping machine, and has the sensitivity to disentangle the history of light production associated with EBL fluctuations. SPHEREx will search for an EOR component its to minimum required level through component separation and spectral fitting techniques optimized for the near-IR. In addition to broad-band intensity mapping that enhances and extends the Euclid survey, uniquely SPHEREx will enable tomography of cosmic large scale structure using line tracers such as Lya, Ha, Hb, O[II] and O[III], as highlighted in community workshops and AAS special sessions over the past several years.

Heat transfer assembly for a fluorescent lamp and fixture

DOEpatents

Siminovitch, M.J.; Rubenstein, F.M.; Whitman, R.E.

1992-12-29

In a lighting fixture including a lamp and a housing, a heat transfer structure is disclosed for reducing the minimum lamp wall temperature of a fluorescent light bulb. The heat transfer structure, constructed of thermally conductive material, extends from inside the housing to outside the housing, transferring heat energy generated from a fluorescent light bulb to outside the housing where the heat energy is dissipated to the ambient air outside the housing. Also disclosed is a method for reducing minimum lamp wall temperatures. Further disclosed is an improved lighting fixture including a lamp, a housing and the aforementioned heat transfer structure. 11 figs.

Effect of Light Intensity and Photoperiod on Growth and Biochemical Composition of a Local Isolate of Nostoc calcicola.

PubMed

Khajepour, Fateme; Hosseini, Seyed Abbas; Ghorbani Nasrabadi, Rasoul; Markou, Giorgos

2015-08-01

A study was conducted to investigate the effect of light intensity (21, 42, and 63 μmol photons m(-2) s(-1)) and photoperiod (8:16, 12:12, and 16:8 h light/dark) on the biomass production and its biochemical composition (total carotenoids, chlorophyll a, phycoerythrin (PE), phycocyanin (PC) and allophycocyanin (APC), total protein, and carbohydrates) of a local isolate of Nostoc calcicola. The results revealed that N. calcicola prefers dim light; however, the most of the levels of light intensity and photoperiod investigated did not have a significant impact on biomass production. Increasing light intensity biomass content of chlorophyll a, PE, PC, APC, and total protein decreased, while total carotenoids and carbohydrate increased. The same behavior was observed also when light duration (photoperiod) increased. The interaction effect of increasing light intensity and photoperiod resulted in an increase of carbohydrate and total carotenoids, and to the decrease of chlorophyll a, PE, PC, APC, and total protein content. The results indicate that varying the light regime, it is capable to manipulate the biochemical composition of the local isolate of N. calcicola, producing either valuable phycobiliproteins or proteins under low light intensity and shorter photoperiods, or producing carbohydrates and carotenoids under higher light intensities and longer photoperiods.

Long-term effect of beach replenishment on natural recovery of shallow Posidonia oceanica meadows

NASA Astrophysics Data System (ADS)

González-Correa, José M.; Torquemada, Yolanda Fernández; Sánchez Lizaso, José Luis

2008-03-01

The recovery capacity of shallow Posidonia oceanica meadows degraded by beach replenishment eighteen years before was assessed in two impacted meadows and compared with other two undisturbed localities. Inside each locality, we selected randomly three sites separated by 500-1000 m. At site level we study the vitality of P. oceanica meadow assessing the vegetative growth, leaf characteristics, and non-structural carbohydrates of the plants. Additionally, at locality level, silt-clay fraction, organic matter, pH and light intensity incident on the sea bottom were measured to evaluate the environmental conditions. Covering of P. oceanica was significantly lower at the impacted localities while amount of dead "matte" was higher. Leaf production of horizontal rhizomes (14.6 ± 1.11 vs 19.47 ± 1.45 leaves y -1), net total rhizomes recruitment (2.33 ± 0.17 vs 4.3 ± 0.33 branches y -1) and starch concentration (43.625 ± 0.67 vs 54.45 ± 0.74 mg per g of rhizome) at impacted meadows were significantly lower than controls. Leaf features, epiphytes biomass, colonization, elongation and horizontal and vertical rhizome production did not show significant differences. Sediments at impacted localities contained higher silt-clay fraction and higher organic matter load while pH was lower. Light intensity on the sea bottom measured at all localities was over the minimum light requirements estimated for P. oceanica. Our results show that the press impact produced by beach replenishment was enduring in the time slowing natural recovery by 45%. This impact may be related with changes in the sediment features.

Light intensity compressor

DOEpatents

Rushford, Michael C.

1990-02-06

In a system for recording images having vastly differing light intensities over the face of the image, a light intensity compressor is provided that utilizes the properties of twisted nematic liquid crystals to compress the image intensity. A photoconductor or photodiode material that is responsive to the wavelength of radiation being recorded is placed adjacent a layer of twisted nematic liquid crystal material. An electric potential applied to a pair of electrodes that are disposed outside of the liquid crystal/photoconductor arrangement to provide an electric field in the vicinity of the liquid crystal material. The electrodes are substantially transparent to the form of radiation being recorded. A pair of crossed polarizers are provided on opposite sides of the liquid crystal. The front polarizer linearly polarizes the light, while the back polarizer cooperates with the front polarizer and the liquid crystal material to compress the intensity of a viewed scene. Light incident upon the intensity compressor activates the photoconductor in proportion to the intensity of the light, thereby varying the field applied to the liquid crystal. The increased field causes the liquid crystal to have less of a twisting effect on the incident linearly polarized light, which will cause an increased percentage of the light to be absorbed by the back polarizer. The intensity of an image may be compressed by forming an image on the light intensity compressor.

Light intensity compressor

DOEpatents

Rushford, Michael C.

1990-01-01

In a system for recording images having vastly differing light intensities over the face of the image, a light intensity compressor is provided that utilizes the properties of twisted nematic liquid crystals to compress the image intensity. A photoconductor or photodiode material that is responsive to the wavelength of radiation being recorded is placed adjacent a layer of twisted nematic liquid crystal material. An electric potential applied to a pair of electrodes that are disposed outside of the liquid crystal/photoconductor arrangement to provide an electric field in the vicinity of the liquid crystal material. The electrodes are substantially transparent to the form of radiation being recorded. A pair of crossed polarizers are provided on opposite sides of the liquid crystal. The front polarizer linearly polarizes the light, while the back polarizer cooperates with the front polarizer and the liquid crystal material to compress the intensity of a viewed scene. Light incident upon the intensity compressor activates the photoconductor in proportion to the intensity of the light, thereby varying the field applied to the liquid crystal. The increased field causes the liquid crystal to have less of a twisting effect on the incident linearly polarized light, which will cause an increased percentage of the light to be absorbed by the back polarizer. The intensity of an image may be compressed by forming an image on the light intensity compressor.

Spin texture and magnetoroton excitations at nu=1/3.

PubMed

Groshaus, Javier G; Dujovne, Irene; Gallais, Yann; Hirjibehedin, Cyrus F; Pinczuk, Aron; Tan, Yan-Wen; Stormer, Horst; Dennis, Brian S; Pfeiffer, Loren N; West, Ken W

2008-02-01

Neutral spin texture (ST) excitations at nu=1/3 are directly observed for the first time by resonant inelastic light scattering. They are determined to involve two simultaneous spin flips. At low magnetic fields, the ST energy is below that of the magnetoroton minimum. With increasing in-plane magnetic field these mode energies cross at a critical ratio of the Zeeman and Coulomb energies of eta(c)=0.020+/-0.001. Surprisingly, the intensity of the ST mode grows with temperature in the range in which the magnetoroton modes collapse. The temperature dependence is interpreted in terms of a competition between coexisting phases supporting different excitations. We consider the role of the ST excitations in activated transport at nu=1/3.

Stratospheric sounding by infrared heterodyne spectroscopy

NASA Technical Reports Server (NTRS)

Abbas, M. M.; Kunde, V. G.; Mumma, M. J.; Kostiuk, T.; Buhl, D.; Frerking, M. A.

1978-01-01

Intensity profiles of infrared spectral lines of stratospheric constituents can be fully resolved with a heterodyne spectrometer of sufficiently high resolution. The constituents' vertical distributions can then be evaluated accurately by analytic inversion of the measured line profiles. Estimates of the detection sensitivity of a heterodyne receiver are given in terms of minimum detectable volume mixing ratios of stratospheric constituents, indicating a large number of minor constituents which can be studied. Stratospheric spectral line shapes, and the resolution required to measure them are discussed in light of calculated synthetic line profiles for some stratospheric molecules in a model atmosphere. The inversion technique for evaluation of gas concentration profiles is briefly described and applications to synthetic lines of O3, CO2, CH4 and N2O are given.

Resistivity of a simple metal from room temperature to 10 to the 6th K

NASA Astrophysics Data System (ADS)

Milchberg, H. M.; Freeman, R. R.; Davey, S. C.; More, R. M.

1988-11-01

The resistivity of nearly solid-density Al was measured as a function of temperature over 4 orders of magnitude above ambient by observing the self-reflection of an intense, less than 0.5 psec, 308-nm light pulse incident on a planar Al target. As an increasing function of electron temperature, the resistivity is observed initially to increase, reach a maximum which is relatively constant over an extended temperature range, and then decrease at the highest temperatures. The broad maximum is interpreted as resistivity saturation, a condition in which the mean free path of the conduction electrons reaches a minimum value as a function of temperature, regardless of the extent of any further disorder in the material.

Optimizing light delivery for a photoacoustic surgical system

NASA Astrophysics Data System (ADS)

Eddins, Blackberrie; Lediju Bell, Muyinatu A.

2017-03-01

This work explores light delivery optimization for a photoacoustic surgical system previously proposed to provide real-time, intraoperative visualization of the internal carotid arteries hidden by bone during minimally invasive neurosurgeries. Monte Carlo simulations were employed to study 3D light propagation in tissue. For a 2.4 mm diameter drill shaft and 2.9 mm spherical drill tip, the optimal fiber distance from the drill shaft was 2 mm, determined from the maximum normalized fluence seen by the artery. A single fiber was insufficient to deliver light to arteries separated by a minimum of 8 mm. Using similar drill geometry and the optimal 2 mm fiber-to-drill shaft distance, Zemax ray tracing simulations were employed to propagate a 950 nm wavelength Gaussian beam through one or more 600 μm core diameter optical fibers, and the resulting optical beam profile was detected on the representative bone surface. For equally spaced fibers, a single merged optical profile formed with 7 or more fibers, determined by thresholding the resulting light profile images at 1/e times the maximum intensity. The corresponding spot size was larger than that of a single fiber transmitting the same input energy, thus reducing the fluence delivered to the sphenoid bone and enabling higher energies within safety limits. A prototype was designed and built based on these optimization parameters. The methodology we used to optimize our light delivery system to surround surgical tools is generalizable to multiple interventional photoacoustic applications.

Concealing with structured light.

PubMed

Sun, Jingbo; Zeng, Jinwei; Wang, Xi; Cartwright, Alexander N; Litchinitser, Natalia M

2014-02-13

While making objects less visible (or invisible) to a human eye or a radar has captured people's imagination for centuries, current attempts towards realization of this long-awaited functionality range from various stealth technologies to recently proposed cloaking devices. A majority of proposed approaches share a number of common deficiencies such as design complexity, polarization effects, bandwidth, losses and the physical size or shape requirement complicating their implementation especially at optical frequencies. Here we demonstrate an alternative way to conceal macroscopic objects by structuring light itself. In our approach, the incident light is transformed into an optical vortex with a dark core that can be used to conceal macroscopic objects. Once such a beam passed around the object it is transformed back into its initial Gaussian shape with minimum amplitude and phase distortions. Therefore, we propose to use that dark core of the vortex beam to conceal an object that is macroscopic yet small enough to fit the dark (negligibly low intensity) region of the beam. The proposed concealing approach is polarization independent, easy to fabricate, lossless, operates at wavelengths ranging from 560 to 700 nm, and can be used to hide macroscopic objects providing they are smaller than vortex core.

Han's model parameters for microalgae grown under intermittent illumination: Determined using particle swarm optimization.

PubMed

Pozzobon, Victor; Perre, Patrick

2018-01-21

This work provides a model and the associated set of parameters allowing for microalgae population growth computation under intermittent lightning. Han's model is coupled with a simple microalgae growth model to yield a relationship between illumination and population growth. The model parameters were obtained by fitting a dataset available in literature using Particle Swarm Optimization method. In their work, authors grew microalgae in excess of nutrients under flashing conditions. Light/dark cycles used for these experimentations are quite close to those found in photobioreactor, i.e. ranging from several seconds to one minute. In this work, in addition to producing the set of parameters, Particle Swarm Optimization robustness was assessed. To do so, two different swarm initialization techniques were used, i.e. uniform and random distribution throughout the search-space. Both yielded the same results. In addition, swarm distribution analysis reveals that the swarm converges to a unique minimum. Thus, the produced set of parameters can be trustfully used to link light intensity to population growth rate. Furthermore, the set is capable to describe photodamages effects on population growth. Hence, accounting for light overexposure effect on algal growth. Copyright © 2017 Elsevier Ltd. All rights reserved.

Laser biostimulation therapy planning supported by imaging

NASA Astrophysics Data System (ADS)

Mester, Adam R.

2018-04-01

Ultrasonography and MR imaging can help to identify the area and depth of different lesions, like injury, overuse, inflammation, degenerative diseases. The appropriate power density, sufficient dose and direction of the laser treatment can be optimally estimated. If required minimum 5 mW photon density and required optimal energy dose: 2-4 Joule/cm2 wouldn't arrive into the depth of the target volume - additional techniques can help: slight compression of soft tissues can decrease the tissue thickness or multiple laser diodes can be used. In case of multiple diode clusters light scattering results deeper penetration. Another method to increase the penetration depth is a second pulsation (in kHz range) of laser light. (So called continuous wave laser itself has inherent THz pulsation by temporal coherence). Third solution of higher light intensity in the target volume is the multi-gate technique: from different angles the same joint can be reached based on imaging findings. Recent developments is ultrasonography: elastosonography and tissue harmonic imaging with contrast material offer optimal therapy planning. While MRI is too expensive modality for laser planning images can be optimally used if a diagnostic MRI already was done. Usual DICOM images offer "postprocessing" measurements in mm range.

A novel inter-fibre light coupling sensor probe using plastic optical fibre for ethanol concentration monitoring at initial production rate

NASA Astrophysics Data System (ADS)

Memon, Sanober F.; Lewis, Elfed; Pembroke, J. Tony; Chowdhry, Bhawani S.

2017-04-01

A novel, low cost and highly sensitive optical fibre probe sensor for concentration measurement of ethanol solvent (C2H5OH) corresponding to bio-ethanol production rate by an algae is reported. The principle of operation of the sensor is based on inter-fibre light coupling through an evanescent field interaction to couple the light between two multimode fibres mounted parallel to each other at a minimum possible separation i.e. < 1mm. The sensor was fabricated using a low cost 1000um plastic optical fibre (POF) and was characterized for real time measurement in the broadband spectrum including visible and near infra-red. The wavelength dependency of this sensor design was also investigated by post processing analysis of real time data and hence the optimum wavelength range determined. The proposed sensor has shown significant response in the range of 0.005 - 0.1 %v/v (%volume/volume or volume concentration) which depicts the high sensitivity for monitoring very minute changes in concentration corresponding refractive index changes of the solution. Numerically, sensor has shown the sensitivity of 21945 intensity counts/%v/v or 109.7 counts per every 0.0050 %v/v.

Noise filtering via electromagnetically induced transparency

NASA Astrophysics Data System (ADS)

Jeong, Taek; Bae, In-Ho; Moon, Han Seb

2017-01-01

We report on the intensity-noise reduction of pseudo-thermal light via electromagnetically induced transparency (EIT) in the Λ-type system of the 5S1/2-5P1/2 transition in 87Rb. Noise filtering of the pseudo-thermal probe light was achieved via an EIT filter and measured according to the degree of intensity noise of the pseudo-thermal probe light. Reductions in the intensity and spectral noise of the pseudo-thermal probe light with the EIT filter were observed using the direct intensity fluctuation and heterodyne detection technique, respectively. Comparison of the intensity noise of the pseudo-thermal probe light before and after passing through the EIT filter revealed a significant reduction in the intensity noise.

Characteristic Analysis Light Intensity Sensor Based On Plastic Optical Fiber At Various Configuration

NASA Astrophysics Data System (ADS)

Arifin, A.; Lusiana; Yunus, Muhammad; Dewang, Syamsir

2018-03-01

This research discusses the light intensity sensor based on plastic optical fiber. This light intensity sensor is made of plastic optical fiber consisting of two types, namely which is cladding and without cladding. Plastic optical fiber used multi-mode step-index type made of polymethyl metacrylate (PMMA). The infrared LED emits light into the optical fiber of the plastic and is subsequently received by the phototransistor to be converted to an electric voltage. The sensor configuration is made with three models: straight configuration, U configuration and gamma configuration with cladding and without cladding. The measured light source uses a 30 Watt high power LED with a light intensity of 0 to 10 Klux. The measured light intensity will affect the propagation of light inside the optical fiber sensor. The greater the intensity of the measured light, the greater the output voltage that is read on the computer. The results showed that the best optical fiber sensor characteristics were obtained in U configuration. Sensors with U-configuration without cladding had the best sensitivity and resolution values of 0.0307 volts/Klux and 0.0326 Klux. The advantages of this measuring light intensity based on the plastic optical fiber instrument are simple, easy-to-make operational systems, low cost, high sensitivity and resolution.

PERIOD–COLOR AND AMPLITUDE–COLOR RELATIONS AT MAXIMUM AND MINIMUM LIGHT FOR RR LYRAE STARS IN THE SDSS STRIPE 82 REGION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ngeow, Chow-Choong; Kanbur, Shashi M.; Schrecengost, Zachariah

Investigation of period–color (PC) and amplitude–color (AC) relations at the maximum and minimum light can be used to probe the interaction of the hydrogen ionization front (HIF) with the photosphere and the radiation hydrodynamics of the outer envelopes of Cepheids and RR Lyraes. For example, theoretical calculations indicated that such interactions would occur at minimum light for RR Lyrae and result in a flatter PC relation. In the past, the PC and AC relations have been investigated by using either the ( V − R ){sub MACHO} or ( V − I ) colors. In this work, we extend previousmore » work to other bands by analyzing the RR Lyraes in the Sloan Digital Sky Survey Stripe 82 Region. Multi-epoch data are available for RR Lyraes located within the footprint of the Stripe 82 Region in five ( ugriz ) bands. We present the PC and AC relations at maximum and minimum light in four colors: ( u − g ){sub 0}, ( g − r ){sub 0}, ( r − i ){sub 0}, and ( i − z ){sub 0}, after they are corrected for extinction. We found that the PC and AC relations for this sample of RR Lyraes show a complex nature in the form of flat, linear or quadratic relations. Furthermore, the PC relations at minimum light for fundamental mode RR Lyrae stars are separated according to the Oosterhoff type, especially in the ( g − r ){sub 0} and ( r − i ){sub 0} colors. If only considering the results from linear regressions, our results are quantitatively consistent with the theory of HIF-photosphere interaction for both fundamental and first overtone RR Lyraes.« less

14 CFR 29.1389 - Position light distribution and intensities.

Code of Federal Regulations, 2013 CFR

2013-01-01

... be provided by new equipment with light covers and color filters in place. Intensities must be... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Position light distribution and intensities... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Equipment Lights § 29.1389...

14 CFR 29.1389 - Position light distribution and intensities.

Code of Federal Regulations, 2012 CFR

2012-01-01

... be provided by new equipment with light covers and color filters in place. Intensities must be... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Position light distribution and intensities... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Equipment Lights § 29.1389...

14 CFR 29.1389 - Position light distribution and intensities.

Code of Federal Regulations, 2014 CFR

2014-01-01

... be provided by new equipment with light covers and color filters in place. Intensities must be... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Position light distribution and intensities... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Equipment Lights § 29.1389...

14 CFR 29.1389 - Position light distribution and intensities.

Code of Federal Regulations, 2011 CFR

2011-01-01

... be provided by new equipment with light covers and color filters in place. Intensities must be... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Position light distribution and intensities... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Equipment Lights § 29.1389...

Foraging mechanisms of siscowet lake trout (Salvelinus namaycush siscowet) on pelagic prey

USGS Publications Warehouse

Keyler, Trevor D.; Hrabik, Thomas R.; Austin, C. Lee; Gorman, Owen T.; Mensinger, Allen F.

2015-01-01

The reaction distance, angle of attack, and foraging success were determined for siscowet lake trout (Salvelinus namaycush siscowet) during laboratory trials under lighting conditions that approximated downwelling spectral irradiance and intensity (9.00 × 108–1.06 × 1014 photons m− 2 s− 1) at daytime depths. Siscowet reaction distance in response to golden shiners (Notemigonus crysoleucas) was directly correlated with increasing light intensity until saturation at 1.86 × 1011 photons m− 2 s− 1, above which reaction distance was constant within the range of tested light intensities. At the lowest tested light intensity, sensory detection was sufficient to locate prey at 25 ± 2 cm, while increasing light intensities increased reaction distance up to 59 ± 2 cm at 1.06 × 1014 photons m− 2 s− 1. Larger prey elicited higher reaction distances than smaller prey at all light intensities while moving prey elicited higher reaction distances than stationary prey at the higher light intensities (6.00 × 109 to 1.06 × 1014 photons m− 2 s− 1). The capture and consumption of prey similarly increased with increasing light intensity while time to capture decreased with increasing light intensity. The majority of orientations toward prey occurred within 120° of the longitudinal axis of the siscowet's eyes, although reaction distances among 30° increments along the entire axis were not significantly different. The developed predictive model will help determine reaction distances for siscowet in various photic environments and will help identify the mechanisms and behavior that allow for low light intensity foraging within freshwater systems.

Indocyanine green fluorescence angiography for quantitative evaluation of in situ parathyroid gland perfusion and function after total thyroidectomy.

PubMed

Lang, Brian Hung-Hin; Wong, Carlos K H; Hung, Hing Tsun; Wong, Kai Pun; Mak, Ka Lun; Au, Kin Bun

2017-01-01

Because the fluorescent light intensity on an indocyanine green fluorescence angiography reflects the blood perfusion within a focused area, the fluorescent light intensity in the remaining in situ parathyroid glands may predict postoperative hypocalcemia risk after total thyroidectomy. Seventy patients underwent intraoperative indocyanine green fluorescence angiography after total thyroidectomy. Any parathyroid glands with a vascular pedicle was left in situ while any parathyroid glands without pedicle or inadvertently removed was autotransplanted. After total thyroidectomy, an intravenous 2.5 mg indocyanine green fluorescence angiography was given and real-time fluorescent images of the thyroid bed were recorded using the SPY imaging system (Novadaq, Ontario, Canada). The fluorescent light intensity of each indocyanine green fluorescence angiography as well as the average and greatest fluorescent light intensity in each patient were calculated. Postoperative hypocalcemia was defined as adjusted calcium <2.00 mmol/L within 24 hours. The fluorescent light intensity between discolored and normal-looking indocyanine green fluorescence angiographies was similar (P = .479). No patients with a greatest fluorescent light intensity >150% developed postoperative hypocalcemia while 9 (81.8%) patients with a greatest fluorescent light intensity ≤150% did. Similarly, no patients with an average fluorescent light intensity >109% developed PH while 9 (30%) with an average fluorescent light intensity ≤109% did. The greatest fluorescent light intensity was more predictive than day-0 postoperative hypocalcemia (P = .027) and % PTH drop day-0 to 1 (P < .001). Indocyanine green fluorescence angiography is a promising operative adjunct in determining residual parathyroid glands function and predicting postoperative hypocalcemia risk after total thyroidectomy. Copyright © 2016 Elsevier Inc. All rights reserved.

The bundling of actin with polyethylene glycol 8000 in the presence and absence of gelsolin.

PubMed Central

Goverman, J; Schick, L A; Newman, J

1996-01-01

Actin filament and bundle formation occur in the cytosol under conditions of very high total macromolecular concentration. In this study we have utilized the inert molecule polyethylene glycol 8000 (PEG) as a means of simulating crowded conditions in vitro. Column-purified Ca-actin was polymerized in the absence and presence of gelsolin (to regulate mean filament lengths between 50 and 5000 mers) and PEG (2-8%) using various concentrations of KCl and/or 2 mM divalent cations. Bundling was characterized by the scattered light intensity and mean diffusion coefficients obtained from dynamic light scattering, as well as by fluorescence and phase-contrast microscopy. The minimum concentration of KCl required for bundling decreases both with increasing concentration of PEG at a fixed mean filament length, and with decreasing filament length at a fixed concentration of PEG. In the absence of divalent cation, bundling is reversible on dilution, as determined by intensity levels, diffusion coefficients, and microscopy. However, with either 2 mM Mg2+ or Ca2+ added, bundling is irreversible under conditions of higher PEG concentrations or longer filaments, indicating that osmotic pressure effects cannot fully explain actin bundling with PEG. Weaker divalent cation-binding sites on actin as well as disulfide bonds appear to be involved in the irreversible bundling. Images FIGURE 7 PMID:8874022

The Arguments and Data in Favor of Minimum Grading

ERIC Educational Resources Information Center

Carifio, James; Carey, Theodore

2013-01-01

The arguments and for and against minimum grading systems have grown increasingly more intense and acrimonious in the past decade. However, there has been an absence of empirical data, theory and clear comparative analyses of conflicting points of view. Critics of minimum grading contend that the practice will produce grade inflation and social…

Light-Irradiation Wavelength and Intensity Changes Influence Aflatoxin Synthesis in Fungi

PubMed Central

Suzuki, Tadahiro

2018-01-01

Fungi respond to light irradiation by forming conidia and occasionally synthesizing mycotoxins. Several light wavelengths, such as blue and red, affect the latter. However, the relationship between light irradiation and mycotoxin synthesis varies depending on the fungal species or strain. This study focused on aflatoxin (AF), which is a mycotoxin, and the types of light irradiation that increase AF synthesis. Light-irradiation tests using the visible region indicated that blue wavelengths in the lower 500 nm region promoted AF synthesis. In contrast, red wavelengths of 660 nm resulted in limited significant changes compared with dark conditions. Irradiation tests with different intensity levels indicated that a low light intensity increased AF synthesis. For one fungal strain, light irradiation decreased the AF synthesis under all wavelength conditions. However, the decrease was mitigated by 525 nm low intensity irradiation. Thus, blue-green low intensity irradiation may increase AF synthesis in fungi. PMID:29304012

14 CFR 25.1389 - Position light distribution and intensities.

Code of Federal Regulations, 2012 CFR

2012-01-01

... provided by new equipment with light covers and color filters in place. Intensities must be determined with... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Position light distribution and intensities... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Lights § 25.1389 Position...

14 CFR 27.1389 - Position light distribution and intensities.

Code of Federal Regulations, 2012 CFR

2012-01-01

... provided by new equipment with light covers and color filters in place. Intensities must be determined with... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Position light distribution and intensities... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Lights § 27.1389 Position...

14 CFR 27.1389 - Position light distribution and intensities.

Code of Federal Regulations, 2011 CFR

2011-01-01

... provided by new equipment with light covers and color filters in place. Intensities must be determined with... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Position light distribution and intensities... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Lights § 27.1389 Position...

14 CFR 25.1389 - Position light distribution and intensities.

Code of Federal Regulations, 2013 CFR

2013-01-01

... provided by new equipment with light covers and color filters in place. Intensities must be determined with... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Position light distribution and intensities... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Lights § 25.1389 Position...

14 CFR 27.1389 - Position light distribution and intensities.

Code of Federal Regulations, 2013 CFR

2013-01-01

... provided by new equipment with light covers and color filters in place. Intensities must be determined with... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Position light distribution and intensities... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Lights § 27.1389 Position...

14 CFR 25.1389 - Position light distribution and intensities.

Code of Federal Regulations, 2011 CFR

2011-01-01

... provided by new equipment with light covers and color filters in place. Intensities must be determined with... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Position light distribution and intensities... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Lights § 25.1389 Position...

14 CFR 25.1389 - Position light distribution and intensities.

Code of Federal Regulations, 2014 CFR

2014-01-01

... provided by new equipment with light covers and color filters in place. Intensities must be determined with... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Position light distribution and intensities... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Lights § 25.1389 Position...

14 CFR 27.1389 - Position light distribution and intensities.

Code of Federal Regulations, 2014 CFR

2014-01-01

... provided by new equipment with light covers and color filters in place. Intensities must be determined with... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Position light distribution and intensities... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Lights § 27.1389 Position...

Bumblebees Perform Well-Controlled Landings in Dim Light.

PubMed

Reber, Therese; Dacke, Marie; Warrant, Eric; Baird, Emily

2016-01-01

To make a smooth touchdown when landing, an insect must be able to reliably control its approach speed as well as its body and leg position-behaviors that are thought to be regulated primarily by visual information. Bumblebees forage and land under a broad range of light intensities and while their behavior during the final moments of landing has been described in detail in bright light, little is known about how this is affected by decreasing light intensity. Here, we investigate this by characterizing the performance of bumblebees, B. terrestris, landing on a flat platform at two different orientations (horizontal and vertical) and at four different light intensities (ranging from 600 lx down to 19 lx). As light intensity decreased, the bees modified their body position and the distance at which they extended their legs, suggesting that the control of landing in these insects is visually mediated. Nevertheless, the effect of light intensity was small and the landings were still well controlled, even in the dimmest light. We suggest that the changes in landing behavior that occurred in dim light might represent adaptations that allow the bees to perform smooth landings across the broad range of light intensities at which they are active.

Minimum-Light Spectral Classifications for M-Type Mira Variables

NASA Astrophysics Data System (ADS)

Wing, Robert F.

2015-08-01

Many bright, well-known Mira variables, including most of the 378 stars for which the AAVSO publishes predicted dates of maximum and minimum in its annual Bulletins, have never been spectroscopically observed close to the time of minimum light, and consequently their catalogued ranges in spectral type are often grossly and misleadingly under-represented. In an effort to improve this situation, for the past 12 years I have been using my 6-color system of narrow-band classification photometry to observe Miras predicted to be near minimum light at the times of my biannual observing runs with the CTIO 0.9-m telescope (operated by the SMARTS consortium). The 6-color system measures the 7100 A band of TiO, which serves to classify stars in the interval K4 to M8, and the 1.06 micron band of VO, which is effective for stars of type M8 and later. To date I have made 431 observations of approximately 220 different (and mostly southern) Miras. Examples are shown of the observed 6-color spectra, and the classifications derived from them.

Abnormal environmental light exposure in the intensive care environment.

PubMed

Fan, Emily P; Abbott, Sabra M; Reid, Kathryn J; Zee, Phyllis C; Maas, Matthew B

2017-08-01

We sought to characterize ambient light exposure in the intensive care unit (ICU) environment to identify patterns of light exposure relevant to circadian regulation. A light monitor was affixed to subjects' bed at eye level in a modern intensive care unit and continuously recorded illuminescence for at least 24h per subject. Blood was sampled hourly and measured for plasma melatonin. Subjects underwent hourly vital sign and bedside neurologic assessments. Care protocols and the ICU environment were not modified for the study. A total of 67,324 30-second epochs of light data were collected from 17 subjects. Light intensity peaked in the late morning, median 64.1 (interquartile range 19.7-138.7) lux. The 75th percentile of light intensity exceeded 100lx only between 9AM and noon, and never exceeded 150lx. There was no correlation between melatonin amplitude and daytime, nighttime or total light exposure (Spearman's correlation coefficients all <0.2 and p>0.5). Patients' environmental light exposure in the intensive care unit is consistently low and follows a diurnal pattern. No effect of nighttime light exposure was observed on melatonin secretion. Inadequate daytime light exposure in the ICU may contribute to abnormal circadian rhythms. Copyright © 2017 Elsevier Inc. All rights reserved.

Effects of Light Intensity and Color on the Biomass, Extracellular Red Pigment, and Citrinin Production of Monascus ruber.

PubMed

Wang, Liling; Dai, Yang; Chen, Wanping; Shao, Yanchun; Chen, Fusheng

2016-12-21

Light is a crucial environmental signal for fungi. In this work, the effects of different light intensities and colors on biomass, Monascus pigments (MPs) and citrinin production of Monascus ruber M7 were investigated. We have demonstrated that low intensity of blue light (500 lx) decreased Monascus biomass, increased MPs accumulation via upregulation of MpigA, MpigB, and MpigJ genes expression, but had no significant influence on citrinin production. High intensity of blue light (1500 lx) decreased citrinin accumulation but had no significant influence on biomass and MPs production after 14 days cultivation. Low intensity of green light (500 lx) stimulated citrinin production via upregulation of pksCT, mrl1, mrl2, and ctnA genes expression. One putative red light photoreceptor and two putative green light photoreceptors were identified in M. ruber M7. These observations will not only guide the practical production of Monascus but also contribute to our understanding light effects on Monascus.

Galactic Cosmic Ray Intensity in the Upcoming Minimum of the Solar Activity Cycle

NASA Astrophysics Data System (ADS)

Krainev, M. B.; Bazilevskaya, G. A.; Kalinin, M. S.; Svirzhevskaya, A. K.; Svirzhevskii, N. S.

2018-03-01

During the prolonged and deep minimum of solar activity between cycles 23 and 24, an unusual behavior of the heliospheric characteristics and increased intensity of galactic cosmic rays (GCRs) near the Earth's orbit were observed. The maximum of the current solar cycle 24 is lower than the previous one, and the decline in solar and, therefore, heliospheric activity is expected to continue in the next cycle. In these conditions, it is important for an understanding of the process of GCR modulation in the heliosphere, as well as for applied purposes (evaluation of the radiation safety of planned space flights, etc.), to estimate quantitatively the possible GCR characteristics near the Earth in the upcoming solar minimum ( 2019-2020). Our estimation is based on the prediction of the heliospheric characteristics that are important for cosmic ray modulation, as well as on numeric calculations of GCR intensity. Additionally, we consider the distribution of the intensity and other GCR characteristics in the heliosphere and discuss the intercycle variations in the GCR characteristics that are integral for the whole heliosphere (total energy, mean energy, and charge).

UNCOVERING THE INTRINSIC VARIABILITY OF GAMMA-RAY BURSTS

NASA Astrophysics Data System (ADS)

Golkhou, V. Zach; Butler, Nathaniel R

2014-08-01

We develop a robust technique to determine the minimum variability timescale for gamma-ray burst (GRB) light curves, utilizing Haar wavelets. Our approach averages over the data for a given GRB, providing an aggregate measure of signal variation while also retaining sensitivity to narrow pulses within complicated time series. In contrast to previous studies using wavelets, which simply define the minimum timescale in reference to the measurement noise floor, our approach identifies the signature of temporally smooth features in the wavelet scaleogram and then additionally identifies a break in the scaleogram on longer timescales as a signature of a true, temporally unsmooth light curve feature or features. We apply our technique to the large sample of Swift GRB gamma-ray light curves and for the first time—due to the presence of a large number of GRBs with measured redshift—determine the distribution of minimum variability timescales in the source frame. We find a median minimum timescale for long-duration GRBs in the source frame of Δtmin = 0.5 s, with the shortest timescale found being on the order of 10 ms. This short timescale suggests a compact central engine (3000 km). We discuss further implications for the GRB fireball model and present a tantalizing correlation between the minimum timescale and redshift, which may in part be due to cosmological time dilation.

Dissimilarity of yellow-blue surfaces under neutral light sources differing in intensity: separate contributions of light intensity and chroma.

PubMed

Tokunaga, Rumi; Logvinenko, Alexander D; Maloney, Laurence T

2008-01-01

Observers viewed two side-by-side arrays each of which contained three yellow Munsell papers, three blue, and one neutral Munsell. Each array was illuminated uniformly and independently of the other. The neutral light source intensities were 1380, 125, or 20 lux. All six possible combinations of light intensities were set as illumination conditions. On each trial, observers were asked to rate the dissimilarity between each chip in one array and each chip in the other by using a 30-point scale. Each pair of surfaces in each illumination condition was judged five times. We analyzed this data using non-metric multi-dimensional scaling to determine how light intensity and surface chroma contributed to dissimilarity and how they interacted. Dissimilarities were captured by a three-dimensional configuration in which one dimension corresponded to differences in light intensity.

On the Intensity Profile of Electric Lamps and Light Bulbs

ERIC Educational Resources Information Center

Bacalla, Xavier; Salumbides, Edcel John

2013-01-01

We demonstrate that the time profile of the light intensity from domestic lighting sources exhibits simple yet interesting properties that foster lively student discussions. We monitor the light intensity of an industrial fluorescent lamp (also known as TL) and an incandescent bulb using a photodetector connected to an oscilloscope. The light…

Light-mediated predation by northern squawfish on juvenile Chinook salmon

USGS Publications Warehouse

Petersen, James H.; Gadomski, Dena M.

1994-01-01

Northern squawfish Ptychocheilus oregonensis cause significant mortality of juvenile salmon in the lower Columbia River Basin (U.S.A.). The effects of light intensity on this predator-prey interaction were examined with laboratory experiments and modelling studies. In laboratory experiments, the rate of capture of subyearling chinook salmon Oncorhynchus tshawytscha by northern squawfish was inversely related to light intensity. In a large raceway, about five times more salmon were captured during 4 h periods of relative darkness (0–03 Ix) than during periods with high light intensity (160 Ix). The rate of predation could be manipulated by increasing or decreasing light intensity.A simulation model was developed for visual predators that encounter, attack, and capture juvenile salmon, whose schooling behaviour was light-sensitive. The model was fitted to laboratory results using a Monte Carlo filtering procedure. Model-predicted predation rate was especially sensitive to the visual range of predators at low light intensity and to predator search speed at high light. Modelling results also suggested that predation by northern squawfish on juvenile salmon may be highest across a narrow window of fight intensity.

Lighting Condition Analysis for Mars Moon Phobos

NASA Technical Reports Server (NTRS)

Li, Zu Qun; Crues, Edwin Z.; Bielski, Paul; De Carufel, Guy

2016-01-01

A manned mission to Phobos may be an important precursor and catalyst for the human exploration of Mars, as it will fully demonstrate the technologies for a successful Mars mission. A comprehensive understanding of Phobos' environment such as lighting condition and gravitational acceleration are essential to the mission success. The lighting condition is one of many critical factors for landing zone selection, vehicle power subsystem design, and surface mobility vehicle path planning. Due to the orbital characteristic of Phobos, the lighting condition will change dramatically from one Martian season to another. This study uses high fidelity computer simulation to investigate the lighting conditions, specifically the solar radiation flux over the surface, on Phobos. Ephemeris data from the Jet Propulsion Laboratory (JPL) DE405 model was used to model the state of the Sun, the Earth, and Mars. An occultation model was developed to simulate Phobos' self-shadowing and its solar eclipses by Mars. The propagated Phobos' state was compared with data from JPL's Horizon system to ensure the accuracy of the result. Results for Phobos lighting condition over one Martian year are presented in this paper, which include length of solar eclipse, average solar radiation intensity, surface exposure time, total maximum solar energy, and total surface solar energy (constrained by incident angle). The results show that Phobos' solar eclipse time changes throughout the Martian year with the maximum eclipse time occurring during the Martian spring and fall equinox and no solar eclipse during the Martian summer and winter solstice. Solar radiation intensity is close to minimum at the summer solstice and close to maximum at the winter solstice. Total surface exposure time is longer near the north pole and around the anti- Mars point. Total maximum solar energy is larger around the anti-Mars point. Total surface solar energy is higher around the anti-Mars point near the equator. The results from this study and others like it will be important in determining landing site selection, vehicle system design and mission operations for the human exploration of Phobos and subsequently Mars.

Effect of light on growth, intracellular and extracellular pigment production by five pigment-producing filamentous fungi in synthetic medium.

PubMed

Velmurugan, Palanivel; Lee, Yong Hoon; Venil, Chidambaram Kulandaisamy; Lakshmanaperumalsamy, Perumalsamy; Chae, Jong-Chan; Oh, Byung-Taek

2010-04-01

The competence of the living creatures to sense and respond to light is well known. The effect of darkness and different color light quality on biomass, extracellular and intracellular pigment yield of five potent pigment producers Monascus purpureus, Isaria farinosa, Emericella nidulans, Fusarium verticillioides and Penicillium purpurogenum, with different color shades such as red, pink, reddish brown and yellow, were investigated. Incubation in total darkness increased the biomass, extracellular and intracellular pigment production in all the fungi. Extracellular red pigment produced by M. purpureus resulted maximum in darkness 36.75 + or - 2.1 OD and minimum in white unscreened light 5.90 + or - 1.1 OD. Similarly, intracellular red pigment produced by M. purpureus resulted maximum in darkness 18.27 + or - 0.9 OD/g and minimum in yellow light 8.03 + or - 0.6 OD/g of substrate. The maximum biomass production was also noticed in darkness 2.51 g/L and minimum in yellow light 0.5 g/L of dry weight. In contrast, growth of fungi in green and yellow wavelengths resulted in low biomass and pigment yield. It was found that darkness, (red 780-622 nm, blue 492-455 nm) and white light influenced pigment and biomass yield. Copyright 2009 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

An air flow sensor for neonatal mechanical ventilation applications based on a novel fiber-optic sensing technique.

PubMed

Battista, L; Sciuto, S A; Scorza, A

2013-03-01

In this work, a simple and low-cost air flow sensor, based on a novel fiber-optic sensing technique has been developed for monitoring air flows rates supplied by a neonatal ventilator to support infants in intensive care units. The device is based on a fiber optic sensing technique allowing (a) the immunity to light intensity variations independent by measurand and (b) the reduction of typical shortcomings affecting all biomedical fields (electromagnetic interference and patient electrical safety). The sensing principle is based on the measurement of transversal displacement of an emitting fiber-optic cantilever due to action of air flow acting on it; the fiber tip displacement is measured by means of a photodiode linear array, placed in front of the entrance face of the emitting optical fiber in order to detect its light intensity profile. As the measurement system is based on a detection of the illumination pattern, and not on an intensity modulation technique, it results less sensitive to light intensity fluctuation independent by measurand than intensity-based sensors. The considered technique is here adopted in order to develop two different configurations for an air flow sensor suitable for the measurement of air flow rates typically occurring during mechanical ventilation of newborns: a mono-directional and a bi-directional transducer have been proposed. A mathematical model for the air flow sensor is here proposed and a static calibration of two different arrangements has been performed: a measurement range up to 3.00 × 10(-4) m(3)∕s (18.0 l∕min) for the mono-directional sensor and a measurement range of ±3.00 × 10(-4) m(3)∕s (±18.0 l∕min) for the bi-directional sensor are experimentally evaluated, according to the air flow rates normally encountered during tidal breathing of infants with a mass lower than 10 kg. Experimental data of static calibration result in accordance with the proposed theoretical model: for the mono-directional configuration, the coefficient of determination r(2) is equal to 0.997; for the bi-directional configuration, the coefficient of determination r(2) is equal to 0.990 for positive flows (inspiration) and 0.988 for negative flows (expiration). Measurement uncertainty δQ of air flow rate has been evaluated by means of the propagation of distributions and the percentage error in the arrangement of bi-directional sensor ranges from a minimum of about 0.5% at -18.0 l∕min to a maximum of about 9% at -12.0 l∕min.

An air flow sensor for neonatal mechanical ventilation applications based on a novel fiber-optic sensing technique

NASA Astrophysics Data System (ADS)

Battista, L.; Sciuto, S. A.; Scorza, A.

2013-03-01

In this work, a simple and low-cost air flow sensor, based on a novel fiber-optic sensing technique has been developed for monitoring air flows rates supplied by a neonatal ventilator to support infants in intensive care units. The device is based on a fiber optic sensing technique allowing (a) the immunity to light intensity variations independent by measurand and (b) the reduction of typical shortcomings affecting all biomedical fields (electromagnetic interference and patient electrical safety). The sensing principle is based on the measurement of transversal displacement of an emitting fiber-optic cantilever due to action of air flow acting on it; the fiber tip displacement is measured by means of a photodiode linear array, placed in front of the entrance face of the emitting optical fiber in order to detect its light intensity profile. As the measurement system is based on a detection of the illumination pattern, and not on an intensity modulation technique, it results less sensitive to light intensity fluctuation independent by measurand than intensity-based sensors. The considered technique is here adopted in order to develop two different configurations for an air flow sensor suitable for the measurement of air flow rates typically occurring during mechanical ventilation of newborns: a mono-directional and a bi-directional transducer have been proposed. A mathematical model for the air flow sensor is here proposed and a static calibration of two different arrangements has been performed: a measurement range up to 3.00 × 10-4 m3/s (18.0 l/min) for the mono-directional sensor and a measurement range of ±3.00 × 10-4 m3/s (±18.0 l/min) for the bi-directional sensor are experimentally evaluated, according to the air flow rates normally encountered during tidal breathing of infants with a mass lower than 10 kg. Experimental data of static calibration result in accordance with the proposed theoretical model: for the mono-directional configuration, the coefficient of determination r2 is equal to 0.997; for the bi-directional configuration, the coefficient of determination r2 is equal to 0.990 for positive flows (inspiration) and 0.988 for negative flows (expiration). Measurement uncertainty δQ of air flow rate has been evaluated by means of the propagation of distributions and the percentage error in the arrangement of bi-directional sensor ranges from a minimum of about 0.5% at -18.0 l/min to a maximum of about 9% at -12.0 l/min.

The effect of light intensity on image quality in endoscopic ear surgery.

PubMed

McCallum, R; McColl, J; Iyer, A

2018-05-16

Endoscopic ear surgery is a rapidly developing field with many advantages. But endoscopes can reach temperatures of over 110°C at the tip, raising safety concerns. Reducing the intensity of the light source reduces temperatures produced. However, quality of images at lower light intensities has not yet been studied. We set out to study the effect of light intensity on image quality in EES. Prospective study of patients undergoing EES from April to October 2016. Consecutive images of the same operative field at 10%, 30%, 50% and 100% light intensities were taken. Eight international experts were asked to each evaluate 100 anonymised, randomised images. District General Hospital. Twenty patients. Images were evaluated on a 5-point Likert scale (1 = significantly worse than average; 5 = significantly better than average) for detail of anatomy; colour contrast; overall quality; and suitability for operating. Mean scores for photographs at 10%, 30%, 50% and 100% light intensity were 3.22 (SD 0.93), 3.15 (SD 0.84), 3.08 (SD 0.88) and 3.10 (SD 0.86), respectively. In ANOVA models for the scores on each of the scales (anatomy, colour contrast, overall quality and suitability for operating), the effects of rater and patient were highly significant (P < .0005) but light intensity was non-significant (P = .34, .32, .21, .15, respectively). Images taken during surgery by our endoscope and operative camera have no loss of quality when taken at lower light intensities. We recommend the surgeon considers use of lower light intensities in endoscopic ear surgery. © 2018 John Wiley & Sons Ltd.

A method for improving the light intensity distribution in dental light-curing units.

PubMed

Arikawa, Hiroyuki; Takahashi, Hideo; Minesaki, Yoshito; Muraguchi, Kouichi; Matsuyama, Takashi; Kanie, Takahito; Ban, Seiji

2011-01-01

A method for improving the uniformity of the radiation light from dental light-curing units (LCUs), and the effect on the polymerization of light-activated composite resin are investigated. Quartz-tungsten halogen, plasma-arc, and light-emitting diode LCUs were used, and additional optical elements such as a mixing tube and diffusing screen were employed to reduce the inhomogeneity of the radiation light. The distribution of the light intensity from the light guide tip was measured across the guide tip, as well as the distribution of the surface hardness of the light-activated resin emitted with the LCUs. Although the additional optical elements caused 13.2-25.9% attenuation of the light intensity, the uniformity of the light intensity of the LCUs was significantly improved in the modified LCUs, and the uniformity of the surface hardness of the resin was also improved. Our results indicate that the addition of optical elements to the LCU may be a simple and effective method for reducing inhomogeneity in radiation light from the LCUs.

Design Information for Emergency Operations Centers.

DTIC Science & Technology

1983-06-01

STC 40-45 4. Visual privacy. Sound Reflectances: 5. Electrical survey. Ceiling: NRC 50 6. Adequate lighting. Floor: NRC 25 7. Adequate thermal comfort . 4...ceiling to 7. Adequate thermal comfort . reduce noise. 8. Image appropriate for authority 4. 60-in.-high minimum wall panels. given. 5. 110-V outlets as...tions. 5. Electrical supply. 2. 9-ft minimum for open plan office 6. Adequate lighting, schemes. 7. Adequate thermal comfort . 3. Enclosing walls: STC 40

Large area pulsed solar simulator

NASA Technical Reports Server (NTRS)

Kruer, Mark A. (Inventor)

1999-01-01

An advanced solar simulator illuminates the surface a very large solar array, such as one twenty feet by twenty feet in area, from a distance of about twenty-six feet with an essentially uniform intensity field of pulsed light of an intensity of one AMO, enabling the solar array to be efficiently tested with light that emulates the sun. Light modifiers sculpt a portion of the light generated by an electrically powered high power Xenon lamp and together with direct light from the lamp provide uniform intensity illumination throughout the solar array, compensating for the square law and cosine law reduction in direct light intensity, particularly at the corner locations of the array. At any location within the array the sum of the direct light and reflected light is essentially constant.

Dynamics and stoichiometry of nutrients and phytoplankton in waters influenced by the oxygen minimum zone in the eastern tropical Pacific

NASA Astrophysics Data System (ADS)

Franz, Jasmin; Krahmann, Gerd; Lavik, Gaute; Grasse, Patricia; Dittmar, Thorsten; Riebesell, Ulf

2012-04-01

The tropical South East Pacific is characterized by strong coastal upwelling on the narrow continental shelf and an intense oxygen minimum zone (OMZ) in the intermediate water layer. These hydrographic properties are responsible for a permanent supply of intermediate water masses to the surface rich in nutrients and with a remarkably low inorganic N:P stoichiometry. To investigate the impact of OMZ-influenced upwelling waters on phytoplankton growth, elemental and taxonomical composition we measured hydrographic and biogeochemical parameters along an east-west transect at 10°S in the tropical South East Pacific, stretching from the upwelling region above the narrow continental shelf to the well-stratified oceanic section of the eastern boundary regime. New production in the area of coastal upwelling was driven by large-sized phytoplankton (e.g. diatoms) with generally low N:P ratios (<16:1). While nitrate and phosphate concentrations were at levels not limiting phytoplankton growth along the entire transect, silicate depletion prohibited diatom growth further off-shore. A deep chlorophyll a maximum consisting of pico-/nano- (Synechococcus, flagellates) and microphytoplankton occurred within a pronounced thermocline in subsurface waters above the shelf break and showed intermediate N:P ratios close to Redfield proportions. High PON:POP (>20:1) ratios were observed in the stratified open ocean section of the transect, coinciding with the abundance of two strains of the pico-cyanobacterium Prochlorococcus; a high-light adapted strain in the surface layer and a low-light adapted strain occurring along the oxic-anoxic transition zone below the thermocline. Excess phosphate present along the entire transect did not appear to stimulate growth of nitrogen-fixing phytoplankton, as pigment fingerprinting did not indicate the presence of diazotrophic cyanobacteria at any of our sampling stations. Instead, a large fraction of the excess phosphate generated within the oxygen minimum zone was consumed by non-Redfield production of large phytoplankton in shelf surface waters.

14 CFR 27.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Maximum intensities in overlapping beams of forward and rear position lights. 27.1395 Section 27.1395 Aeronautics and Space FEDERAL AVIATION... Equipment Lights § 27.1395 Maximum intensities in overlapping beams of forward and rear position lights. No...

14 CFR 25.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Maximum intensities in overlapping beams of forward and rear position lights. 25.1395 Section 25.1395 Aeronautics and Space FEDERAL AVIATION... Equipment Lights § 25.1395 Maximum intensities in overlapping beams of forward and rear position lights. No...

14 CFR 29.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Maximum intensities in overlapping beams of forward and rear position lights. 29.1395 Section 29.1395 Aeronautics and Space FEDERAL AVIATION... Equipment Lights § 29.1395 Maximum intensities in overlapping beams of forward and rear position lights. No...

Peculiarities of cosmic ray modulation in the solar minimum 23/24

NASA Astrophysics Data System (ADS)

Alania, M. V.; Modzelewska, R.; Wawrzynczak, A.

2014-06-01

We study changes of the galactic cosmic ray (GCR) intensity for the ending period of the solar cycle 23 and the beginning of the solar cycle 24 using neutron monitors experimental data. We show that an increase of the GCR intensity in 2009 is generally related with decrease of the solar wind velocity U, the strength B of the interplanetary magnetic field (IMF), and the drift in negative (A < 0) polarity epoch. We present that temporal changes of rigidity dependence of the GCR intensity variation, before reaching maximum level in 2009 and after it, do not noticeably differ from each other. The rigidity spectrum of the GCR intensity variations calculated based on neutron monitors data (for rigidities > 10 GV) is hard in the minimum and near-minimum epoch. We do not recognize any nonordinary changes in the physical mechanism of modulation of the GCR intensity in the rigidity range of GCR particles to which neutron monitors respond. We compose 2-D nonstationary model of transport equation to describe variations of the GCR intensity for 1996-2012 including the A > 0 (1996-2001) and the A < 0 (2002-2012) periods; diffusion coefficient of cosmic rays for rigidity 10-15 GV is increased by 30% in 2009 (A < 0) comparing with 1996 (A > 0). We believe that the proposed model is relatively realistic, and obtained results are satisfactorily compatible with neutron monitors data.

Effects of light intensity and quality on phycobiliprotein accumulation in the cyanobacterium Nostoc sphaeroides Kützing.

PubMed

Ma, Rui; Lu, Fan; Bi, Yonghong; Hu, Zhengyu

2015-08-01

To assess the effects of light intensity and quality on the growth and phycobiliproteins (PBP) accumulation in Nostoc sphaeroides Kützing (N. sphaeroides). Dry weights, dry matter, protein, chlorophyll and PBP contents were higher under 90 μmol m(-2) s(-1) than under other intensities (both higher and lower). Phycocyanin and allophycocyanin increased with light intensity while phycoerythrin decreased. Fresh weights, protein and PBP contents increased at the highest rates under blue light. Red light resulted in higher values of dry matter, phycocyanin and chlorophyll a. White light at 90 μmol m(-2) s(-1) or blue light 30 μmol m(-2) s(-1) were optimal for the growth and phycobiliprotein accumulation in N. sphaeroides.

Disruptive effects of light pollution on sleep in free-living birds: Season and/or light intensity-dependent?

PubMed

Raap, Thomas; Sun, Jiachen; Pinxten, Rianne; Eens, Marcel

2017-11-01

Light pollution or artificial light at night (ALAN) is an increasing anthropogenic environmental pollutant posing an important potential threat for wildlife. Evidence of its effects on animal physiology and behaviour is accumulating. However, in order to effectively mitigate light pollution it is important to determine which factors contribute to the severity of effects of ALAN. In this experimental study we explored whether there are seasonal-dependent effects of ALAN on sleep in free-living great tits (Parus major), an important model species. Additionally, we looked at whether light intensity determined the severity of effects of ALAN on sleep. We therefore exposed animals to artificial light inside the nest box (3lx) in December (winter) and February (pre-breeding season). Results from February were compared with the results from a previous study in February, using a lower light intensity (1.6lx). We found little evidence for a season-dependent response. Effects of ALAN hardly differed between high and low light intensity. ALAN disrupted sleep with as main effect a decrease in sleep duration (≈-40min) as animals woke up earlier (≈-24min). However, compared to a natural dark situation sleep onset was delayed by high but not by low light intensity of ALAN. Our study underlines earlier found disruptive effects of ALAN on sleep of free-living animals. While we found no conclusive evidence for seasonal or light intensity-dependent effects of ALAN, additional experimental work using lower light intensities might show such differences. Examining potential management options is crucial in mitigating disruptive effects of light pollution, which will be an important focus for future studies. Copyright © 2017 Elsevier B.V. All rights reserved.

Health Benefits of Light-Intensity Physical Activity: A Systematic Review of Accelerometer Data of the National Health and Nutrition Examination Survey (NHANES).

PubMed

Füzéki, Eszter; Engeroff, Tobias; Banzer, Winfried

2017-09-01

The health effects of light-intensity physical activity (PA) are not well known today. We conducted a systematic review to assess the association of accelerometer-measured light-intensity PA with modifiable health outcomes in adults and older adults. A systematic literature search up to March 2016 was performed in the PubMed, EMBASE, Web of Science and Google Scholar electronic databases, without language limitations, for studies of modifiable health outcomes in adults and older adults in the National Health and Nutrition Examination Survey accelerometer dataset. Overall, 37 cross-sectional studies and three longitudinal studies were included in the analysis, with considerable variation observed between the studies with regard to their operationalization of light-intensity PA. Light-intensity PA was found to be beneficially associated with obesity, markers of lipid and glucose metabolism, and mortality. Few data were available on musculoskeletal outcomes and results were mixed. Observational evidence that light-intensity PA can confer health benefits is accumulating. Currently inactive or insufficiently active people should be encouraged to engage in PA of any intensity. If longitudinal and intervention studies corroborate our findings, the revision of PA recommendations to include light-intensity activities, at least for currently inactive populations, might be warranted.

Apparatus for measuring particle properties

DOEpatents

Rader, Daniel J.; Castaneda, Jaime N.; Grasser, Thomas W.; Brockmann, John E.

1998-01-01

An apparatus for determining particle properties from detected light scattered by the particles. The apparatus uses a light beam with novel intensity characteristics to discriminate between particles that pass through the beam and those that pass through an edge of the beam. The apparatus can also discriminate between light scattered by one particle and light scattered by multiple particles. The particle's size can be determined from the intensity of the light scattered. The particle's velocity can be determined from the elapsed time between various intensities of the light scattered.

Accuracy of intensity and inclinometer output of three activity monitors for identification of sedentary behavior and light-intensity activity.

PubMed

Carr, Lucas J; Mahar, Matthew T

2012-01-01

Purpose. To examine the accuracy of intensity and inclinometer output of three physical activity monitors during various sedentary and light-intensity activities. Methods. Thirty-six participants wore three physical activity monitors (ActiGraph GT1M, ActiGraph GT3X+, and StepWatch) while completing sedentary (lying, sitting watching television, sitting using computer, and standing still) light (walking 1.0 mph, pedaling 7.0 mph, pedaling 15.0 mph) intensity activities under controlled settings. Accuracy for correctly categorizing intensity was assessed for each monitor and threshold. Accuracy of the GT3X+ inclinometer function (GT3X+Incl) for correctly identifying anatomical position was also assessed. Percentage agreement between direct observation and the monitor recorded time spent in sedentary behavior and light intensity was examined. Results. All monitors using all thresholds accurately identified over 80% of sedentary behaviors and 60% of light-intensity walking time based on intensity output. The StepWatch was the most accurate in detecting pedaling time but unable to detect pedal workload. The GT3X+Incl accurately identified anatomical position during 70% of all activities but demonstrated limitations in discriminating between activities of differing intensity. Conclusions. Our findings suggest that all three monitors accurately measure most sedentary and light-intensity activities although choice of monitors should be based on study-specific needs.

Light Intensity physical activity and sedentary behavior in relation to body mass index and grip strength in older adults: cross-sectional findings from the Lifestyle Interventions and Independence for Elders (LIFE) study.

PubMed

Bann, David; Hire, Don; Manini, Todd; Cooper, Rachel; Botoseneanu, Anda; McDermott, Mary M; Pahor, Marco; Glynn, Nancy W; Fielding, Roger; King, Abby C; Church, Timothy; Ambrosius, Walter T; Gill, Thomas M; Gill, Thomas

2015-01-01

Identifying modifiable determinants of fat mass and muscle strength in older adults is important given their impact on physical functioning and health. Light intensity physical activity and sedentary behavior are potential determinants, but their relations to these outcomes are poorly understood. We evaluated associations of light intensity physical activity and sedentary time-assessed both objectively and by self-report-with body mass index (BMI) and grip strength in a large sample of older adults. We used cross-sectional baseline data from 1130 participants of the Lifestyle Interventions and Independence for Elders (LIFE) study, a community-dwelling sample of relatively sedentary older adults (70-89 years) at heightened risk of mobility disability. Time spent sedentary and in light intensity activity were assessed using an accelerometer worn for 3-7 days (Actigraph GT3X) and by self-report. Associations between these exposures and measured BMI and grip strength were evaluated using linear regression. Greater time spent in light intensity activity and lower sedentary times were both associated with lower BMI. This was evident using objective measures of lower-light intensity, and both objective and self-reported measures of higher-light intensity activity. Time spent watching television was positively associated with BMI, while reading and computer use were not. Greater time spent in higher but not lower intensities of light activity (assessed objectively) was associated with greater grip strength in men but not women, while neither objectively assessed nor self-reported sedentary time was associated with grip strength. In this cross-sectional study, greater time spent in light intensity activity and lower sedentary times were associated with lower BMI. These results are consistent with the hypothesis that replacing sedentary activities with light intensity activities could lead to lower BMI levels and obesity prevalence among the population of older adults. However, longitudinal and experimental studies are needed to strengthen causal inferences.

Towards dosimetry for photodynamic diagnosis with the low-level dose of photosensitizer.

PubMed

Buzalewicz, Igor; Hołowacz, Iwona; Ulatowska-Jarża, Agnieszka; Podbielska, Halina

2017-08-01

Contemporary medicine does not concern the issue of dosimetry in photodynamic diagnosis (PDD) but follows the photosensitizer (PS) producers recommendation. Most preclinical and clinical PDD studies indicate a considerable variation in the possibility of visualization and treatment, as e.g. in case of cervix lesions. Although some of these variations can be caused by the different histological subtypes or various tumor geometries, the issue of varying PS concentration in the tumor tissue volume is definitely an important factor. Therefore, there is a need to establish the objective and systematic PDD dosimetry protocol regarding doses of light and photosensitizers. Four different irradiation sources investigated in PDD (literature) were used for PS excitation. The PS luminescence was examined by means of the non-imaging (spectroscopic) and imaging (wide- and narrow-field of view) techniques. The methodology for low-level intensity photoluminescence (PL) characterization and dedicated image processing algorithm for PS luminescence images analysis were proposed. Further, HeLa cells' cultures penetration by PS was studied by a confocal microscopy. Reducing the PS dose with the choice of proper photoexcitation conditions decreases the PDD procedure costs and the side effects, not affecting the diagnostic efficiency. We determined in vitro the minimum incubation time and photosensitizer concentration of Photolon for diagnostic purposes, for which the Photolon PL can still be observed. It was demonstrated that quantification of PS concentration, choice of proper photoexcitation source, appropriate adjustment of light dose and PS penetration of cancer cells may improve the low-level luminescence photodynamic diagnostics performance. Practical effectiveness of the PDD strongly depends on irradiation source parameters (bandwidth, maximum intensity, half-width) and their optimization is the main conditioning factor for low-level intensity and low-cost PDD. Copyright © 2017 Elsevier B.V. All rights reserved.

First in vivo animal studies on intraocular nanosurgery and multiphoton tomography with low-energy 80-MHz near-infrared femtosecond laser pulses

NASA Astrophysics Data System (ADS)

Konig, Karsten; Wang, Bagui; Krauss, Oliver; Riemann, Iris; Schubert, Harald; Kirste, Sigrun; Fischer, Peter

2004-07-01

We report on a method for refractive laser surgery based on low-energy femtosecond laser pulses provided by ultracompact turn-key non-amplified laser systems. An additional excimer laser is not required for ablation of the stroma. The novel method has the potential to be used for (i) optical flap creation as well as stroma ablation and (ii) for non-invasive flap-free intrastromal ablation. In addition, 3D multiphoton imaging of the cornea can be performed. In particular, we used sub-nanojoule near infrared 80 MHz femtosecond laser pulses for multiphoton imaging of corneal structures with ultrahigh resolution (< 1μm) as well as for highly precise intraocular refractive surgery. Imaging based on two-photon excited cellular autofluorescence and SHG formation in collagen structures was performed at GW/cm2 intensities, whereas destructive optical breakdown for nanoprocessing occurred at TW/cm2 light intensities. These high intensities were realized with sub-nJ pulses within a subfemtoliter intrastromal volume by diffraction-limited focussing with high NA objectives and beam scanning 50 to 140 μm below the epithelial surface. Multiphoton tomography of the cornea was used to determine the target of interest and to visualize intraocular post-laser effects. Histological examination with light- and electron microscopes of laser-exposed porcine and rabbit eyes reveal a minimum intratissue cut size below 1 μm without destructive effects to surrounding collagen structures. LASIK flaps and intracorneal cavities could be realized with high precision using 200 fs, 80 MHz, sub-nanojoule pulses at 800 nm. First studies on 80 MHz femtosecond laser surgery on living rabbits have been performed.

High-resolution recording of particle tracks with in-line holography in a large cryogenic bubble chamber

NASA Astrophysics Data System (ADS)

Harigel, Gert G.

2000-10-01

Holography has been used successfully in combination with conventional optics for the first time in a large cryogenic bubble chamber, the 15-Foot Bubble Chamber at the Fermi National Accelerator Laboratory (FNAL), during a physics run in a high energy neutrino beam. The innovative system combined the reference beam with the object beam, irradiating a conical volume of approx1.5m3. Bubble tracks from neutrino interactions with a width of approx 120 micrometers have been recorded with good contrast. The ratio of intensities of the object light to the reference light striking the film is called the beam branching ratio (BBR). We obtained in our experiment an exceedingly small minimum- observable ration of BBR = (0.54 divided by 0.21) x 107. The technology has the potential for a wide range of applications. This paper describes the various difficulties in achieving the success. It required the development of laser pulse stretching via enhanced closed loop control with slow Q- switching, to overcome excessive heating of the cryogenic liquid by the powerful laser beam. A sophisticated system of light-absorbing baffles had to be installed to avoid stray light reaching the holographic film. Optical decoupling of classical and holographic illumination systems was required. Real and virtual image replay machines for holograms were built, tailored to our illumination technique.

[A mobile sensor for remote detection of natural gas leakage].

PubMed

Zhang, Shuai; Liu, Wen-qing; Zhang, Yu-jun; Kan, Rui-feng; Ruan, Jun; Wang, Li-ming; Yu, Dian-qiang; Dong, Jin-ting; Han, Xiao-lei; Cui, Yi-ben; Liu, Jian-guo

2012-02-01

The detection of natural gas pipeline leak becomes a significant issue for body security, environmental protection and security of state property. However, the leak detection is difficult, because of the pipeline's covering many areas, operating conditions and complicated environment. A mobile sensor for remote detection of natural gas leakage based on scanning wavelength differential absorption spectroscopy (SWDAS) is introduced. The improved soft threshold wavelet denoising was proposed by analyzing the characteristics of reflection spectrum. And the results showed that the signal to noise ratio (SNR) was increased three times. When light intensity is 530 nA, the minimum remote sensitivity will be 80 ppm x m. A widely used SWDAS can make quantitative remote sensing of natural gas leak and locate the leak source precisely in a faster, safer and more intelligent way.

A versatile diffractive maskless lithography for single-shot and serial microfabrication.

PubMed

Jenness, Nathan J; Hill, Ryan T; Hucknall, Angus; Chilkoti, Ashutosh; Clark, Robert L

2010-05-24

We demonstrate a diffractive maskless lithographic system that is capable of rapidly performing both serial and single-shot micropatterning. Utilizing the diffractive properties of phase holograms displayed on a spatial light modulator, arbitrary intensity distributions were produced to form two and three dimensional micropatterns/structures in a variety of substrates. A straightforward graphical user interface was implemented to allow users to load templates and change patterning modes within the span of a few minutes. A minimum resolution of approximately 700 nm is demonstrated for both patterning modes, which compares favorably to the 232 nm resolution limit predicted by the Rayleigh criterion. The presented method is rapid and adaptable, allowing for the parallel fabrication of microstructures in photoresist as well as the fabrication of protein microstructures that retain functional activity.

Fundamental Combustion Processes of Particle-Laden Shear Flows in Solid Fuel Ramjets

DTIC Science & Technology

1990-05-17

permitted observation of the high- intensity , near- surface flame zone. The intensity of the near-surface flame was so strong that it overpowered the light ... intensity of the 100 watt tungsten-halogen lamp used as the schlieren system light source. Figure 9a shows the burning of a 10/40/50 B/Mg/PTFE...rf five millivo’ts from the photodiode), an aorupt increase in light emission, and maximum light intensity . As the heat flux increases, the time for

A light intensity monitoring method based on fiber Bragg grating sensing technology and BP neural network

NASA Astrophysics Data System (ADS)

Li, Lu-Ming; Zhu, Qian; Zhang, Zhi-Guo; Cai, Zhi-Min; Liao, Zhi-Jun; Hu, Zhen-Yan

2017-04-01

In this paper, a light intensity monitoring method based on FBG is proposed. The method establishes a light intensity monitoring model with cantilever beam structure and BP neural network algorithm, which is based on fiber grating sensing technology. The accuracy of the model can meet the requirements of engineering project and it can monitor light intensity in real time. The experimental results show that the method has good stability and high sensitivity.

Extraordinary variation of pump light intensity inside a four-level solid-state laser medium

NASA Astrophysics Data System (ADS)

Qin, Hua; Fu, Rulian; Wang, Zhaoqi; Liu, Juan

2008-08-01

A theoretical investigation of the absorption of the pump light at different intensities through a four-level solid-state laser medium is presented. It is found that the variation of the pump intensity inside the laser medium cannot always simply be dominated by Beer's law. Transmission of the pump light through this laser medium is closely related to the pump intensity itself. In fact, when the pump intensity is relatively low, whose values depend on the characteristics of the medium, the variation of the pump light through the laser medium is consistent with Beer's law. However, while the pump intensity is high enough, the relationship between the transmission of the pump light and its propagation distance is demonstrated to be linear. These theoretical results have been confirmed by the experiment with a medium of YAG:Nd.

Light intensity and the oestrous cycle in albino and normally pigmented mice.

PubMed

Donnelly, H; Saibaba, P

1993-10-01

The effects of light intensity (15-20 lux & 220-290 lux) on the oestrous cycle of albino and normally pigmented mice were examined. The oestrous cycle of both types of mice was shorter at the lower intensity but the difference was significant only with the black mice. The proportion of albino mice from which embryos were recovered was significantly smaller than the proportion of black mice at 15-20 lux but not at 220-290 lux. No significant differences due to strain or light intensity were found in the number of embryos recovered. We conclude that pigmented mice respond in the same way as albino mice to changes in light intensity within the range normally found in laboratory animal accommodation. That is, increased light intensity prolongs the oestrous cycle and the period of vaginal cornification.

Elemental GCR Observations during the 2009-2010 Solar Minimum Period

NASA Technical Reports Server (NTRS)

Lave, K. A.; Israel, M. H.; Binns, W. R.; Christian, E. R.; Cummings, A. C.; Davis, A. J.; deNolfo, G. A.; Leske, R. A.; Mewaldt, R. A.; Stone, E. C.;

Signal intensity influences on the atomic Faraday filter.

PubMed

Luo, Bin; Yin, Longfei; Xiong, Junyu; Chen, Jingbiao; Guo, Hong

2018-06-01

Previous studies of the Faraday anomalous dispersion optical filter (FADOF) mainly focus on the weak signal light filtering, without regard for the influences of the signal light intensity on the filter itself. However, in some applications the signal light is strong enough to change the filter's performance. In this work, the influences of the signal light intensity on the transmittance spectrum is experimentally investigated in a 780 nm Rb85 FADOF in both the line-center and wings operation modes. The results show that the transmittance spectrum varies significantly with the signal light intensity. As the signal light increases, some existing transmittance peaks decline, some new transmittance peaks appear, and the maximum transmittance peak frequency may change. The spectrum in strong signal lights can be quite different from those calculated by programs in the condition of weak signal lights. These results are important for applications of the FADOF in the condition of strong signal lights.

46 CFR 111.60-4 - Minimum cable conductor size.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Minimum cable conductor size. 111.60-4 Section 111.60-4...-GENERAL REQUIREMENTS Wiring Materials and Methods § 111.60-4 Minimum cable conductor size. Each cable conductor must be #18 AWG (0.82 mm2) or larger except— (a) Each power and lighting cable conductor must be...

46 CFR 111.60-4 - Minimum cable conductor size.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Minimum cable conductor size. 111.60-4 Section 111.60-4...-GENERAL REQUIREMENTS Wiring Materials and Methods § 111.60-4 Minimum cable conductor size. Each cable conductor must be #18 AWG (0.82 mm2) or larger except— (a) Each power and lighting cable conductor must be...

Alterations of the lipid content and fatty acid profile of Chlorella protothecoides under different light intensities.

PubMed

Krzemińska, Izabela; Piasecka, Agata; Nosalewicz, Artur; Simionato, Diana; Wawrzykowski, Jacek

2015-11-01

Chlorella protothecoides is a valuable source of lipids that may be used for biodiesel production. The present work shows analysis of the potential of photoheterotrophic cultivation of C. protothecoides under various light intensities aiming to identify the conditions with maximal biomass and lipid content. An increase in light intensity was associated with an increased specific growth rate and a shortened doubling time. Also, the relative total lipid content increased from 24.8% to 37.5% with increase of light intensity. The composition of fatty acid methyl esters was affected by light intensity with the C16-18 fatty acids increased from 76.97% to 90.24% of total fatty acids. However, the content of linolenic acids decreased with the increase of the culture irradiance. These studies indicate that cultures irradiated with high light intensities achieve the minimal specifications for biodiesel quality on linolenic acids and thus are suitable for biodiesel production. Copyright © 2015 Elsevier Ltd. All rights reserved.

Light-Induced Changes of the Circadian Clock of Humans: Increasing Duration is More Effective than Increasing Light Intensity

PubMed Central

Dewan, Karuna; Benloucif, Susan; Reid, Kathryn; Wolfe, Lisa F.; Zee, Phyllis C.

2011-01-01

Study Objectives: To evaluate the effect of increasing the intensity and/or duration of exposure on light-induced changes in the timing of the circadian clock of humans. Design: Multifactorial randomized controlled trial, between and within subject design Setting: General Clinical Research Center (GCRC) of an academic medical center Participants: 56 healthy young subjects (20-40 years of age) Interventions: Research subjects were admitted for 2 independent stays of 4 nights/3 days for treatment with bright or dim-light (randomized order) at a time known to induce phase delays in circadian timing. The intensity and duration of the bright light were determined by random assignment to one of 9 treatment conditions (duration of 1, 2, or 3 hours at 2000, 4000, or 8000 lux). Measurements and Results: Treatment-induced changes in the dim light melatonin onset (DLMO) and dim light melatonin offset (DLMOff) were measured from blood samples collected every 20-30 min throughout baseline and post-treatment nights. Comparison by multi-factor analysis of variance (ANOVA) of light-induced changes in the time of the circadian melatonin rhythm for the 9 conditions revealed that changing the duration of the light exposure from 1 to 3 h increased the magnitude of light-induced delays. In contrast, increasing from moderate (2,000 lux) to high (8,000 lux) intensity light did not alter the magnitude of phase delays of the circadian melatonin rhythm. Conclusions: Results from the present study suggest that for phototherapy of circadian rhythm sleep disorders in humans, a longer period of moderate intensity light may be more effective than a shorter exposure period of high intensity light. Citation: Dewan K; Benloucif S; Reid K; Wolfe LF; Zee PC. Light-induced changes of the circadian clock of humans: increasing duration is more effective than increasing light intensity. SLEEP 2011;34(5):593-599. PMID:21532952

Light-intensity physical activity is associated with insulin resistance in elderly Japanese women independent of moderate-to vigorous-intensity physical activity.

PubMed

Gando, Yuko; Murakami, Haruka; Kawakami, Ryoko; Tanaka, Noriko; Sanada, Kiyoshi; Tabata, Izumi; Higuchi, Mitsuru; Miyachi, Motohiko

2014-02-01

It is unclear whether light physical activity is beneficially associated with insulin resistance, similar to moderate and/or vigorous physical activity. This cross-sectional study was performed to determine the relationship between the amount of light physical activity, as determined with a triaxial accelerometer, and insulin resistance. A total of 807 healthy men and women participated in this study. Physical activity was measured using a triaxial accelerometer worn for 28 days and summarized as light intensity (1.1-2.9 METs) or moderate to vigorous intensity (≥ 3.0 METs). Insulin resistance was evaluated by HOMA_R (FPG [mg/dL] × IRI [μU/mL]/405). The daily time spent in light physical activity was inversely associated with HOMA_R (r = -0.173, P < 0.05). After adjustment for confounders, the association between light physical activity and HOMA_R remained statistically significant (β = -0.119, P < .05). Light physical activity remained significantly associated with HOMA_R following further adjustment for moderate to vigorous intensity activity (β = -0.125, P < .05). Similar results were observed when light physical activity was modeled as quartiles, especially in elderly women. These cross-sectional data suggest that light-intensity physical activity is beneficially associated with insulin resistance in elderly Japanese women.

Wastewater nutrient removal in a mixed microalgae-bacteria culture: effect of light and temperature on the microalgae-bacteria competition.

PubMed

González-Camejo, J; Barat, R; Pachés, M; Murgui, M; Seco, A; Ferrer, J

2018-02-01

The aim of this study was to evaluate the effect of light intensity and temperature on nutrient removal and biomass productivity in a microalgae-bacteria culture and their effects on the microalgae-bacteria competition. Three experiments were carried out at constant temperature and various light intensities: 40, 85 and 125 µE m -2  s -1 . Other two experiments were carried out at variable temperatures: 23 ± 2°C and 28 ± 2°C at light intensity of 85 and 125 µE m -2  s -1 , respectively. The photobioreactor was fed by the effluent from an anaerobic membrane bioreactor. High nitrogen and phosphorus removal efficiencies (about 99%) were achieved under the following operating conditions: 85-125 µE m -2  s -1 and 22 ± 1°C. In the microalgae-bacteria culture studied, increasing light intensity favoured microalgae growth and limited the nitrification process. However, a non-graduated temperature increase (up to 32°C) under the light intensities studied caused the proliferation of nitrifying bacteria and the nitrite and nitrate accumulation. Hence, light intensity and temperature are key parameters in the control of the microalgae-bacteria competition. Biomass productivity significantly increased with light intensity, reaching 50.5 ± 9.6, 80.3 ± 6.5 and 94.3 ± 7.9 mgVSS L -1  d -1 for a light intensity of 40, 85 and 125 µE m -2  s -1 , respectively.

A Guide to the Librarian's Responsibility in Achieving Quality in Lighting and Ventilation.

ERIC Educational Resources Information Center

Mason, Ellsworth

1967-01-01

Quality, not intensity, is the keystone to good library lighting. The single most important problem in lighting is glare caused by extremely intense centers of light. Multiple interfiling of light rays is a factor required in library lighting. A fixture that diffuses light well is basic when light emerges from the fixture. It scatters widely,…

Comet impacts and chemical evolution on the bombarded earth

NASA Technical Reports Server (NTRS)

Oberbeck, Verne R.; Aggarwal, Hans

1992-01-01

Amino acids yields for previously published shock tube experiments are used with minimum Cretaceous-Tertiary (K/T) impactor mass and comet composition to predict AIB amino acid K/T boundary sediment column density. The inferred initial concentration of all amino acids in the K/T sea and in similar primordial seas just after 10 km comet impacts would have been at least 10 exp -7 M. However, sinks for amino acids must also be considered in calculating amino acid concentrations after comet impacts and in assessing the contribution of comets to the origin of life. The changing concentration of cometary amino acids due to ultraviolet light is compared with the equilibrium concentration of amino acids produced in the sea from corona discharge in the atmosphere, deposition in water, and degradation by ultraviolet light. Comets could have been more important than endogenous agents for initial evolution of amino acids. Sites favorable for chemical evolution of amino acids are examined, and it is concluded that chemical evolution could have occurred at or above the surface even during periods of intense bombardment of earth before 3.8 billion years ago.

Apparatus for measuring particle properties

DOEpatents

Rader, D.J.; Castaneda, J.N.; Grasser, T.W.; Brockmann, J.E.

1998-08-11

An apparatus is described for determining particle properties from detected light scattered by the particles. The apparatus uses a light beam with novel intensity characteristics to discriminate between particles that pass through the beam and those that pass through an edge of the beam. The apparatus can also discriminate between light scattered by one particle and light scattered by multiple particles. The particle`s size can be determined from the intensity of the light scattered. The particle`s velocity can be determined from the elapsed time between various intensities of the light scattered. 11 figs.

The ratioed image film thickness meter

NASA Astrophysics Data System (ADS)

Husen, Nicholas M.; Liu, Tianshu; Sullivan, John P.

2018-06-01

A technique for measuring the thickness of a fluorescent oil film is presented. Incident light is cast upon the oil film and the intensity of the luminescent signal from the fluorescent dye is ratioed with the intensity of the incident light which is scattered from the surface of the model. The quotient is independent of the intensity of the incident light and proportional to the film thickness. Experiments are presented supporting that for sufficiently thin films the ratio is independent of the intensity of the incident light as well as independent of the angle from which the experiment is imaged and the angle from which the incident light is cast.

[Investigation of exciting light and plant leaves age effects on chlorophyll fluorescense of radish plants].

PubMed

Nesterenko, T V; Tikhomirov, A A; Shikhov, V N

2012-01-01

The effect of exciting light intensity and leaves age on characteristics of slow stage of chlorophyll fluorescence induction (CFI) of radish leaves has been investigated. Light dependence of the relationship of maximum fluorescence intensity in the peak P and the stationary fluorescence level (F(P)/F(S)) and also light dependence of temporal characteristics of CFI (T0.5 - half decrease of chlorophyll fluorescence intensity during slow stage of fluorescence induction and tmin - summarized CFI characteristics derived by calculating via integral proportional to variable part of illuminated in the result of chlorophyll fluorescence energy during slow stage of CFI) have been studied. Plants were grown in controlled conditions of light culture at 100 Wt/m2 of photosynthetic active radiation (PAR). It has been shown that variability of the characteristics under study, associated with the effect of leaves age, significantly decreases at exciting light intensity equal to 40 Wt/m2 of PAR and more. The lowest effect of leaves age on the value of fluorescence characteristics for T0.5 and tmin and also for F(P)/F(S) ratio was observed at the intensity of exciting fluorescence light of 60 Wt/m2 of PAR. In the researched range of light intensities the temporal characteristics of T0.5 and tmin for uneven-aged radish leaves appeared to be by an order less responsive to the intensity changes of exciting fluorescence light as compared with F(P)/F(S) ratio.

Variation in light intensity with height and time from subsequent lightning return strokes

NASA Technical Reports Server (NTRS)

Jordan, D. M.; Uman, M. A.

1983-01-01

Photographic measurements of relative light intensity as a function of height and time have been conducted for seven return strokes in two lightning flashes at 7.8 and 8.7 km ranges, using film which possesses an approximately constant spectral response in the 300-670 nm range. The amplitude of the initial light peak is noted to decrease exponentially with height, with a decay constant of 0.6-0.8 km. The logarithm of the peak light intensity near the ground is found to be approximately proportional to the initial peak electric field intensity, implying that the current decrease with height may be much slower than the light decrease. Absolute light intensity is presently estimated through the integration of the photographic signals from individual channel segments, in order to simulate the calibrated, all-sky photoelectric data of Guo and Krider (1982).

Smart trigger logic for focal plane arrays

DOEpatents

Levy, James E; Campbell, David V; Holmes, Michael L; Lovejoy, Robert; Wojciechowski, Kenneth; Kay, Randolph R; Cavanaugh, William S; Gurrieri, Thomas M

2014-03-25

An electronic device includes a memory configured to receive data representing light intensity values from pixels in a focal plane array and a processor that analyzes the received data to determine which light values correspond to triggered pixels, where the triggered pixels are those pixels that meet a predefined set of criteria, and determines, for each triggered pixel, a set of neighbor pixels for which light intensity values are to be stored. The electronic device also includes a buffer that temporarily stores light intensity values for at least one previously processed row of pixels, so that when a triggered pixel is identified in a current row, light intensity values for the neighbor pixels in the previously processed row and for the triggered pixel are persistently stored, as well as a data transmitter that transmits the persistently stored light intensity values for the triggered and neighbor pixels to a data receiver.

Noncoherent-intense-pulsed light for the treatment of relapsing hairy intradermal melanocytic nevus after shave excision.

PubMed

Moreno-Arias, G A; Ferrando, J

2001-01-01

Few reports about melanocytic lesions treatment by means of noncoherent-intense-pulsed light (NCIPL) have been published. Here we evaluate the clinical results of a relapsing hairy intradermal melanocytic nevus treated with a noncoherent-intense-pulsed light source. A facial repigmented hairy intradermal melanocytic nevus that relapsed after shave excision, received four treatment sessions of a noncoherent-intense-pulsed light source (EpiLight, ESC Medical Systems Ltd, Israel) with the following parameters: 755 nm, a fluence energy of 40-42.5 J/cm(2), triple mode, a pulse width of 3.8 ms, and a delay of 20 ms, at 4-week intervals. Complete pigment clearance and hair removal was obtained. We have neither observed repigmentation nor hair regrowth after a 6 month-follow-up. No side effects were documented. Noncoherent-intense-pulse light is an effective treatment for hairy-pigmented melanocytic nevus. Copyright 2001 Wiley-Liss, Inc.

Optical clearing of skin using flash lamp-induced enhancement of epidermal permeability.

PubMed

Tuchin, V V; Altshuler, G B; Gavrilova, A A; Pravdin, A B; Tabatadze, D; Childs, J; Yaroslavsky, I V

2006-10-01

Strong light scattering in skin prevents precise targeting of optical energy in therapeutic and diagnostic applications. Optical immersion based on matching refractive index of scattering centers with that of surrounding matter through introduction of an exogenous index-matching agent can alleviate the problem. However, slow diffusion of the index-matching agent through skin barrier makes practical implementation of this approach difficult. We propose a method of accelerating penetration of the index-matching compounds by enhancing skin permeability through creating a lattice of micro-zones (islets) of limited thermal damage in the stratum corneum (SC). A flash lamp (intense pulsed light) system and an island mask with a pattern of absorbing centers (center size approximately 75-120 microm, lattice pitch approximately 450-500 microm) were used to create the lattice of islets of damage (LID). Index-matching agents, such as glucose solution, propylene glycol solution, and glycerol solution, were applied. Experimental results of optical clearing ex vivo rat and pig skin, and ex vivo and in vivo human skin are presented. Optical transmission spectra of the skin samples with LID were measured during some 2 hours after application of index-matching chemical agents. In order to assess and compare the clearing rate under different treatment and clearing agents we calculated the quantity that we call "relative transmittance": T(rel) = I(t)(lambda)/I(0)(lambda), were I(t)(lambda) is the intensity measured at elapsed time t. The dynamics of relative transmittance of skin samples at 470 and 650 nm shows that the implementation of limited thermal damage technique leads to a 3-10-fold increase of optical clearing (rise of transmittance) rate compared to the results obtained when the samples were treated with high-intensity light pulses but without the use of island damage mask (IDM). It was observed from the plotted spectra of relative transmittance that the maximum increase of transmitted light intensity has been obtained with glucose solution as a clearing agent. Noteworthy is the difference in the trend of spectral curves: relative transmittance spectrum for glycerol reveals, on the whole, a greater slope which may be indicative of higher extent of index matching between the scattering centers and base material for this index-matching agent. Under the transillumination of the skin sample by the wide flat beam the more effective clearing (the increase of transmitted intensity) is attained within the hemoglobin absorption bands; with the narrow quasi-collimated beam the higher relative transmittance was observed over the intervals of minimum absorption. The use of specially designed island mask combined with non-laser intensive pulse irradiation produces a lattice of islands of limited thermal damage in SC that substantially enhances the penetration rate of topically applied index-matching agents. The suggested technique gave comparable magnitudes of clearing dynamics enhancement for glucose solution, glycerol solution, and propylene glycol solution applied to mammalian skin.

Generating structured light with phase helix and intensity helix using reflection-enhanced plasmonic metasurface at 2 μm

NASA Astrophysics Data System (ADS)

Zhao, Yifan; Du, Jing; Zhang, Jinrun; Shen, Li; Wang, Jian

2018-04-01

Mid-infrared (2-20 μm) light has been attracting great attention in many areas of science and technology. Beyond the extended wavelength range from visible and near-infrared to mid-infrared, shaping spatial structures may add opportunities to grooming applications of mid-infrared photonics. Here, we design and fabricate a reflection-enhanced plasmonic metasurface and demonstrate efficient generation of structured light with the phase helix and intensity helix at 2 μm. This work includes two distinct aspects. First, structured light (phase helix, intensity helix) generation at 2 μm, which is far beyond the ability of conventional spatial light modulators, is enabled by the metasurface with sub-wavelength engineered structures. Second, the self-referenced intensity helix against environmental noise is generated without using a spatially separated light. The demonstrations may open up advanced perspectives to structured light applications at 2 μm, such as phase helix for communications and non-communications (imaging, sensing) and intensity helix for enhanced microscopy and advanced metrology.

An estimation methode for measurement of ultraviolet radiation during nondestructive testing

NASA Astrophysics Data System (ADS)

Hosseinipanah, M.; Movafeghi, A.; Farvadin, D.

2018-04-01

Dye penetrant testing and magnetic particle testing are among conventional NDT methods. For increased sensitivity, fluorescence dyes and particles can be used with ultraviolet (black) lights. UV flaw detection lights have different spectra. With the help of photo-filters, the output lights are transferred to UV-A and visible zones. UV-A light can be harmful to human eyes in some conditions. In this research, UV intensity and spectrum were obtained by a Radio-spectrometer for two different UV flaw detector lighting systems. According to the standards such as ASTM E709, UV intensity must be at least 10 W/m2 at a distance of 30 cm. Based on our measurements; these features not achieved in some lamps. On the other hand, intensity and effective intensity of UV lights must be below the some limits for prevention of unprotected eye damage. NDT centers are usually using some type of UV measuring devices. A method for the estimation of effective intensity of UV light has been proposed in this research.

Effect of Dynamic Light Application on Cognitive Performance and Well-being of Intensive Care Nurses.

PubMed

Simons, Koen S; Boeijen, Enzio R K; Mertens, Marlies C; Rood, Paul; de Jager, Cornelis P C; van den Boogaard, Mark

2018-05-01

Exposure to bright light has alerting effects. In nurses, alertness may be decreased because of shift work and high work pressure, potentially reducing work performance and increasing the risk for medical errors. To determine whether high-intensity dynamic light improves cognitive performance, self-reported depressive signs and symptoms, fatigue, alertness, and well-being in intensive care unit nurses. In a single-center crossover study in an intensive care unit of a teaching hospital in the Netherlands, 10 registered nurses were randomly divided into 2 groups. Each group worked alternately for 3 to 4 days in patients' rooms with dynamic light and 3 to 4 days in control lighting settings. High-intensity dynamic light was administered through ceiling-mounted fluorescent tubes that delivered bluish white light up to 1700 lux during the daytime, versus 300 lux in control settings. Cognitive performance, self-reported depressive signs and symptoms, fatigue, and well-being before and after each period were assessed by using validated cognitive tests and questionnaires. Cognitive performance, self-reported depressive signs and symptoms, and fatigue did not differ significantly between the 2 light settings. Scores of subjective well-being were significantly lower after a period of working in dynamic light. Daytime lighting conditions did not affect intensive care unit nurses' cognitive performance, perceived depressive signs and symptoms, or fatigue. Perceived quality of life, predominantly in the psychological and environmental domains, was lower for nurses working in dynamic light. © 2018 American Association of Critical-Care Nurses.

Redwood seedling responses to light patterns and intensities

Treesearch

Ronald W. Boldenow; Joe R. McBride

2017-01-01

Coast redwood (Sequoia sempervirens (D. Don) Endl.) seedlings were grown from seed in controlled environments with 16 hour photoperiods using three light patterns that mimicked full shade (constant light level), intermittent high light such as long duration sun flecks (low light with 15 minutes of intense light every 2 hours), and large...

A parallel bubble column system for the cultivation of phototrophic microorganisms.

PubMed

Havel, Jan; Franco-Lara, Ezequiel; Weuster-Botz, Dirk

2008-07-01

An incubator with up to 16 parallel bubble columns was equipped with artificial light sources assuring a light supply with a homogenous light spectrum directly above the bioreactors. Cylindrical light reflecting tubes were positioned around every single bubble column to avoid light scattering effects and to redirect the light from the top onto the cylindrical outer glass surface of each bubble column. The light reflecting tubes were equipped with light intensity filters to control the total light intensity for every single photo-bioreactor. Parallel cultivations of the unicellular obligate phototrophic cyanobacterium, Synechococcus PCC7942, were studied under different constant light intensities ranging from 20 to 102 microE m(-2)s(-1) at a constant humidified air flow rate supplemented with CO(2).

Evaluation of light intensity output of QTH and LED curing devices in various governmental health institutions.

PubMed

Al Shaafi, Mm; Maawadh, Am; Al Qahtani, Mq

2011-01-01

The purpose of this study was to evaluate the light intensity output of quartz-tungsten-halogen (QTH) and light emitting diode (LED) curing devices located at governmental health institutions in Riyadh, Saudi Arabia.Eight governmental institutions were involved in the study. The total number of evaluated curing devices was 210 (120 were QTH and 90 were LED). The reading of the light intensity output for each curing unit was achieved using a digital spectrometer; (Model USB4000 Spectrometer, Ocean Optics Inc, Dunedin, FL, USA). The reading procedure was performed by a single investigator; any recording of light intensity below 300 mW/cm2 was considered unsatisfactory.The result found that the recorded mean values of light intensity output for QTH and LED devices were 260 mW/cm2 and 598 mW/cm2, respectively. The percentage of QTH devices and LED devices considered unsatisfactory was 67.5% and 15.6%, respectively. Overall, the regular assessment of light curing devices using light meters is recommended to assure adequate output for clinical use.

Plants Actively Avoid State Transitions upon Changes in Light Intensity: Role of Light-Harvesting Complex II Protein Dephosphorylation in High Light1[OPEN

PubMed Central

Suorsa, Marjaana; Rantala, Marjaana; Aro, Eva-Mari

2015-01-01

Photosystem II (PSII) core and light-harvesting complex II (LHCII) proteins in plant chloroplasts undergo reversible phosphorylation upon changes in light intensity (being under control of redox-regulated STN7 and STN8 kinases and TAP38/PPH1 and PSII core phosphatases). Shift of plants from growth light to high light results in an increase of PSII core phosphorylation, whereas LHCII phosphorylation concomitantly decreases. Exactly the opposite takes place when plants are shifted to lower light intensity. Despite distinct changes occurring in thylakoid protein phosphorylation upon light intensity changes, the excitation balance between PSII and photosystem I remains unchanged. This differs drastically from the canonical-state transition model induced by artificial states 1 and 2 lights that concomitantly either dephosphorylate or phosphorylate, respectively, both the PSII core and LHCII phosphoproteins. Analysis of the kinase and phosphatase mutants revealed that TAP38/PPH1 phosphatase is crucial in preventing state transition upon increase in light intensity. Indeed, tap38/pph1 mutant revealed strong concomitant phosphorylation of both the PSII core and LHCII proteins upon transfer to high light, thus resembling the wild type under state 2 light. Coordinated function of thylakoid protein kinases and phosphatases is shown to secure balanced excitation energy for both photosystems by preventing state transitions upon changes in light intensity. Moreover, PROTON GRADIENT REGULATION5 (PGR5) is required for proper regulation of thylakoid protein kinases and phosphatases, and the pgr5 mutant mimics phenotypes of tap38/pph1. This shows that there is a close cooperation between the redox- and proton gradient-dependent regulatory mechanisms for proper function of the photosynthetic machinery. PMID:25902812

Modulation of galactic cosmic rays in solar cycles 22-24: Analysis and physical interpretation

NASA Astrophysics Data System (ADS)

Kalinin, M. S.; Bazilevskaya, G. A.; Krainev, M. B.; Svirzhevskaya, A. K.; Svirzhevsky, N. S.; Starodubtsev, S. A.

2017-09-01

This work represents a physical interpretation of cosmic ray modulation in the 22nd-24th solar cycles, including an interpretation of an unusual behavior of their intensity in the last minimum of the solar activity (2008-2010). In terms of the Parker modulation model, which deals with regularly measured heliospheric characteristics, it is shown that the determining factor of the increased intensity of the galactic cosmic rays in the minimum of the 24th solar cycle is an anomalous reduction of the heliospheric magnetic field strength during this time interval under the additional influence of the solar wind velocity and the tilt angle of the heliospheric current sheet. We have used in the calculations the dependence of the diffusion tensor on the rigidity in the form K ij ∝ R 2-μ with μ = 1.2 in the sector zones of the heliospheric magnetic field and with μ = 0.8 outside the sector zones, which leads to an additional amplification of the diffusion mechanism of cosmic ray modulation. The proposed approach allows us to describe quite satisfactorily the integral intensity of protons with an energy above 0.1 GeV and the energy spectra in the minima of the 22nd-24th solar cycles at the same value of the free parameter. The determining factor of the anomalously high level of the galactic cosmic ray intensity in the minimum of the 24th solar cycle is the significant reduction of the heliospheric magnetic field strength during this time interval. The forecast of the intensity level in the minimum of the 25th solar cycle is provided.

Photophoretic trampoline—Interaction of single airborne absorbing droplets with light

NASA Astrophysics Data System (ADS)

Esseling, Michael; Rose, Patrick; Alpmann, Christina; Denz, Cornelia

2012-09-01

We present the light-induced manipulation of absorbing liquid droplets in air. Ink droplets from a printer cartridge are used to demonstrate that absorbing liquids—just like their solid counterparts—can interact with regions of high light intensity due to the photophoretic force. It is shown that droplets follow a quasi-ballistic trajectory after bouncing off a high intensity light sheet. We estimate the intensities necessary for this rebound of airborne droplets and change the droplet trajectories through a variation of the manipulating light field.

Photometric followup investigations on LAMOST survey target Ly And

NASA Astrophysics Data System (ADS)

Lu, Hong-peng; Zhang, Li-yun; Han, Xianming L.; Pi, Qing-feng; Wang, Dai-mei

2017-02-01

We present a low-dispersion spectrum and two sets of CCD photometric light curves of the eclipsing binary LY And for the first time. The spectrum of LY And was classified as G2. We derived an updated ephemeris based on all previously available and our newly acquired minimum light times. Our analyses of LY And light curve minimum times reveals that the differences between calculated and observed minimum times for LY And can be represented by an upward parabolic curve, which means its orbital period is increasing with a rate of 1.88 (± 0.13) × 10-7 days/year. This increase in orbital period may be interpreted as mass transfer from the primary component to the secondary component, with a rate of dM1/dt = -4.54 × 10-8M⊙/year. By analyzing our CCD photometric light curves obtained in 2015, we obtained its photometric solution with the Wilson-Devinney program. This photometric solution also fits very well our light curves obtained in 2014. Our photometric solution shows that LY And is a contact eclipsing binary and its contact factor is f = (17.8 ± 1.9)%. Furthermore, both our spectroscopic and photometric data show no obvious chromospheric activity of LY And.

Performance of Arrowroot (Marantha arundinacea) in various light intensities

NASA Astrophysics Data System (ADS)

Oktafani, M. B.; Supriyono; Budiastuti, MTh S.; Purnomo, D.

2018-03-01

Arrowroot (Marantha arundinacea) is one of the potential food crops to support food security programs. Light intensity is one of the important factors for plant growth. Arrowroot cultivation technology still need further development. Traditionally, arrowroot grows wild under canopy without intentisification of cultivating which have low productivity. The purpose of research was to investigate the suitable light intensity for arrowroot. The experiment was conducted at Jumantono as Experimental Field of Faculty of Agricultural, University of Sebelas Maret Surakarta located in Karanganyar, from March to September 2016. The experiment used a complete randomized block design (CRBD) of light intensity level there are 27400 lux (full sun light), 18900 lux (shaded 31%), 13500 lux (shaded 51%) and 7400 lux (shaded 72%). Each treatment was replicated six times so there were 24 experimental units. The results showed that arrowroot is a low light adaptive plant. Arrowroot under the light intensity 7400 lux (27% full light), the number of leaves and tillers is not significantly different than under full light, although the plant is higher. The highest tuber diameter and length were 1.91 and 25.06 cm, respectively, and tuber weight reached 607.5-651.67 g per plant.

Light Intensity is Important for Hydrogen Production in NaHSO3-Treated Chlamydomonas reinhardtii.

PubMed

Wei, Lanzhen; Yi, Jing; Wang, Lianjun; Huang, Tingting; Gao, Fudan; Wang, Quanxi; Ma, Weimin

2017-03-01

Chlamydomonas reinhardtii is a unicellular green alga that can use light energy to produce H2 from H2O in the background of NaHSO3 treatment. However, the role of light intensity in such H2 production remains elusive. Here, light intensity significantly affected the yield of H2 production in NaHSO3-treated C. reinhardtii, which was consistent with its effects on the content of O2 and the expression and activity of hydrogenase. Further, NaHSO3 was found to be able to remove O2 via a reaction of bisulfite with superoxide anion produced at the acceptor side of PSI, and light intensity affected the reaction rate significantly. Accordingly, high light and strong light but not low light can create an anaerobic environment, which is important to activate hydrogenase and produce H2. Based on the above results, we conclude that light intensity plays an important role in removing O2 and consequently activating hydrogenase and producing H2 in NaHSO3-treated C. reinhardtii. © The Author 2017. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Patterns of habitual physical activity in youth with and without Prader-Willi Syndrome.

PubMed

Castner, Diobel M; Tucker, Jared M; Wilson, Kathleen S; Rubin, Daniela A

2014-11-01

Children classified as overweight or obese and those with disabilities are at a greater risk of not meeting the minimum recommendation of 60 min a day of moderate to vigorous physical activity (PA). Youth with Prader-Willi Syndrome (PWS) appear to participate in less PA compared to nonsyndromal children, likely due to syndrome-related factors. However, description of PA patterns in youth with PWS is lacking. The purpose of this study was to characterize PA in youth with PWS and to compare it to PA in children with nonsyndromal obesity. Twenty-four youth with PWS (ages 8-16 years) and 40 obese children without PWS (OB) (ages 8-11 years) wore accelerometers for eight consecutive days. Data were screened for compliance and classified into PA intensities: sedentary behavior (SED), light (LPA), moderate (MPA), vigorous (VPA) and moderate plus vigorous (MVPA). Youth with PWS spent 19.4% less time in weekly LPA (p=0.007) and 29.8% less time in weekly VPA compared to OB controls (p=0.036). All other intensities were similar between groups. In addition, PWS participated in less LPA and VPA during the weekends compared to OB, and less LPA on weekdays when compared to OB. There was also a trend towards PWS participating in less MVPA during the weekends and less VPA during the weekends than OB controls. There was a trend towards PWS participating in less VPA on weekends compared to weekdays, while OB participated similarly in VPA on weekdays and weekend days. On average, neither PWS nor OB children met minimum MVPA recommendations. The results suggest there is a need to design exercise programs for PWS youth that focus on integrating vigorous intensity activities, especially during the weekends when structured PA may not be available. Copyright © 2014 Elsevier Ltd. All rights reserved.

Light intensity affects the uptake and metabolism of glycine by pakchoi (Brassica chinensis L.)

NASA Astrophysics Data System (ADS)

Ma, Qingxu; Cao, Xiaochuang; Wu, Lianghuan; Mi, Wenhai; Feng, Ying

2016-02-01

The uptake of glycine by pakchoi (Brassica chinensis L.), when supplied as single N-source or in a mixture of glycine and inorganic N, was studied at different light intensities under sterile conditions. At the optimal intensity (414 μmol m-2 s-1) for plant growth, glycine, nitrate, and ammonium contributed 29.4%, 39.5%, and 31.1% shoot N, respectively, and light intensity altered the preferential absorption of N sources. The lower 15N-nitrate in root but higher in shoot and the higher 15N-glycine in root but lower in shoot suggested that most 15N-nitrate uptake by root transported to shoot rapidly, with the shoot being important for nitrate assimilation, and the N contribution of glycine was limited by post-uptake metabolism. The amount of glycine that was taken up by the plant was likely limited by root uptake at low light intensities and by the metabolism of ammonium produced by glycine at high light intensities. These results indicate that pakchoi has the ability to uptake a large quantity of glycine, but that uptake is strongly regulated by light intensity, with metabolism in the root inhibiting its N contribution.

A validated model to predict microalgae growth in outdoor pond cultures subjected to fluctuating light intensities and water temperatures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huesemann, Michael H.; Crowe, Braden J.; Waller, Peter

Here, a microalgae biomass growth model was developed for screening novel strains for their potential to exhibit high biomass productivities under nutrient-replete conditions in outdoor ponds subjected to fluctuating light intensities and water temperatures. Growth is modeled by first estimating the light attenuation by biomass according to a scatter-corrected Beer-Lambert Law, and then calculating the specific growth rate in discretized culture volume slices that receive declining light intensities due to attenuation. The model requires the following experimentally determined strain-specific input parameters: specific growth rate as a function of light intensity and temperature, biomass loss rate in the dark as amore » function of temperature and average light intensity during the preceding light period, and the scatter-corrected biomass light absorption coefficient. The model was successful in predicting the growth performance and biomass productivity of three different microalgae species (Chlorella sorokiniana, Nannochloropsis salina, and Picochlorum sp.) in raceway pond cultures (batch and semi-continuous) subjected to diurnal sunlight intensity and water temperature variations. Model predictions were moderately sensitive to minor deviations in input parameters. To increase the predictive power of this and other microalgae biomass growth models, a better understanding of the effects of mixing-induced rapid light dark cycles on photo-inhibition and short-term biomass losses due to dark respiration in the aphotic zone of the pond is needed.« less

A validated model to predict microalgae growth in outdoor pond cultures subjected to fluctuating light intensities and water temperatures

DOE PAGES

Huesemann, Michael H.; Crowe, Braden J.; Waller, Peter; ...

2015-12-11

Here, a microalgae biomass growth model was developed for screening novel strains for their potential to exhibit high biomass productivities under nutrient-replete conditions in outdoor ponds subjected to fluctuating light intensities and water temperatures. Growth is modeled by first estimating the light attenuation by biomass according to a scatter-corrected Beer-Lambert Law, and then calculating the specific growth rate in discretized culture volume slices that receive declining light intensities due to attenuation. The model requires the following experimentally determined strain-specific input parameters: specific growth rate as a function of light intensity and temperature, biomass loss rate in the dark as amore » function of temperature and average light intensity during the preceding light period, and the scatter-corrected biomass light absorption coefficient. The model was successful in predicting the growth performance and biomass productivity of three different microalgae species (Chlorella sorokiniana, Nannochloropsis salina, and Picochlorum sp.) in raceway pond cultures (batch and semi-continuous) subjected to diurnal sunlight intensity and water temperature variations. Model predictions were moderately sensitive to minor deviations in input parameters. To increase the predictive power of this and other microalgae biomass growth models, a better understanding of the effects of mixing-induced rapid light dark cycles on photo-inhibition and short-term biomass losses due to dark respiration in the aphotic zone of the pond is needed.« less

Red light-induced suppression of gravitropism in moss protonemata

NASA Astrophysics Data System (ADS)

Kern, V. D.; Sack, F. D.

1999-01-01

Moss protonemata are among the few cell types known that both sense and respond to gravity and light. Apical cells of Ceratodon protonemata grow by oriented tip growth which is negatively gravitropic in the dark or positively phototropic in unilateral red light. Phototropism is phytochrome-mediated. To determine whether any gravitropism persists during irradiation, cultures were turned at various angles with respect to gravity and illuminated so that the light and gravity vectors acted either in the same or in different directions. Red light for 24h (≥140nmol m-2s-1) caused the protonemata to be oriented directly towards the light. Similarly, protonemata grew directly towards the light regardless of light position with respect to gravity indicating that all growth is oriented strictly by phototropism, not gravitropism. At light intensities ≤100nmol m-2s-1, no phototropism occurs and the mean protonemal tip angle remains above the horizontal, which is the criterion for negative gravitropism. But those protonemata are not as uniformly upright as they would be in the dark indicating that low intensity red light permits gravitropism but also modulates the response. Protonemata of the aphototropic mutant ptr1 that lacks a functional Pfr chromophore, exhibit gravitropism regardless of red light intensity. This indicates that red light acts via Pfr to modulate gravitropism at low intensities and to suppress gravitropism at intensities ≥140nmol m-2s-1.

Lighting design in the neonatal intensive care unit: practical applications of scientific principles.

PubMed

White, Robert D

2004-06-01

Meeting the varied lighting needs of infants, caregivers, and families has become more complex as our understanding of visual development and perception and the effect of light on circadian rhythms advances. Optimal lighting strategies are discussed for new unit construction, as well as modifications to consider for existing units. In either case, the key concept is that lighting should be provided for the individual needs of each person, rather than the full-room lighting schemes previously used. Ideas gleaned from nonhospital settings, re-introduction of natural light into the neonatal intensive care unit, and new devices such as light-emitting diodes will dramatically change the lighting and visual environment of future neonatal intensive care units.

Effect of various infection-control methods for light-cure units on the cure of composite resins.

PubMed

Chong, S L; Lam, Y K; Lee, F K; Ramalingam, L; Yeo, A C; Lim, C C

1998-01-01

This study (1) compared the curing-light intensity with various barrier infection-control methods used to prevent cross contamination, (2) compared the Knoop hardness value of cured composite resin when various barrier control methods were used, and (3) correlated the hardness of the composite resin with the light-intensity output when different infection-control methods were used. The light-cure unit tips were covered with barriers, such as cellophane wrap, plastic gloves, Steri-shields, and finger cots. The control group had no barrier. Composite resins were then cured for each of the five groups, and their Knoop hardness values recorded. The results showed that there was significant statistical difference in the light-intensity output among the five groups. However, there was no significant statistical difference in the Knoop hardness values among any of the groups. There was also no correlation between the Knoop hardness value of the composite resin with the light-intensity output and the different infection-control methods. Therefore, any of the five infection-control methods could be used as barriers for preventing cross-contamination of the light-cure unit tip, for the light-intensity output for all five groups exceeded the recommended value of 300 W/m2. However, to allow a greater margin of error in clinical situations, the authors recommend that the plastic glove or the cellophane wrap be used to wrap the light-cure tip, since these barriers allowed the highest light-intensity output.

Low Light Diagnostics in Thin-Film Photovoltaics

NASA Astrophysics Data System (ADS)

Shvydka, Diana; Karpov, Victor; Compaan, Alvin

2003-03-01

We study statistics of the major photovoltaic (PV) parameters such as open circuit voltage, short circuit current and fill factor vs. light intensity on a set of nominally identical CdTe/CdS solar cells. We found the most probable parameter values to change with the light intensity as predicted by the standard diode model, while their relative fluctuations increase dramatically under low light. The crossover light intensity is found below which the relative fluctuations of the PV parameters diverge inversely proportional to the square root of the light intensity. We propose a model where the observed fluctuations are due to lateral nonuniformities in the device structure. In particular, the crossover is attributed to the lateral nonuniformity screening length exceeding the device size. >From the practical standpoint, our study introduces a simple uniformity diagnostic technique.

The extended atmosphere of Lambda Pavonis at the time of the emergence of H-emissions from minimum intensity

NASA Technical Reports Server (NTRS)

Sahade, Jorge; Rovira, Marta; Ringuelet, Adela E.; Kondo, Yoji; Cidale, Lydia

1988-01-01

A study of the Be star Lambda Pavonis, particularly of the changes in the Balmer discontinuity in the interval 1949-1982, is presented. Nearly simultaneous observations carried out with the ESO 1.5 m reflector at La Silla and with the IUE satellite correspond to an epoch when the H emission is starting to increase intensity immediately after having reached its minimum strength. These observations suggest the presence of four distinct regions of line formation, with the material moving outward in the transition region.

Arabidopsis nph1 and npl1: blue light receptors that mediate both phototropism and chloroplast relocation.

PubMed

Sakai, T; Kagawa, T; Kasahara, M; Swartz, T E; Christie, J M; Briggs, W R; Wada, M; Okada, K

2001-06-05

UV-A/blue light acts to regulate a number of physiological processes in higher plants. These include light-driven chloroplast movement and phototropism. The NPH1 gene of Arabidopsis encodes an autophosphorylating protein kinase that functions as a photoreceptor for phototropism in response to low-intensity blue light. However, nph1 mutants have been reported to exhibit normal phototropic curvature under high-intensity blue light, indicating the presence of an additional phototropic receptor. A likely candidate is the nph1 homologue, npl1, which has recently been shown to mediate the avoidance response of chloroplasts to high-intensity blue light in Arabidopsis. Here we demonstrate that npl1, like nph1, noncovalently binds the chromophore flavin mononucleotide (FMN) within two specialized PAS domains, termed LOV domains. Furthermore, when expressed in insect cells, npl1, like nph1, undergoes light-dependent autophosphorylation, indicating that npl1 also functions as a light receptor kinase. Consistent with this conclusion, we show that a nph1 npl1 double mutant exhibits an impaired phototropic response under both low- and high-intensity blue light. Hence, npl1 functions as a second phototropic receptor under high fluence rate conditions and is, in part, functionally redundant to nph1. We also demonstrate that both chloroplast accumulation in response to low-intensity light and chloroplast avoidance movement in response to high-intensity light are lacking in the nph1 npl1 double mutant. Our findings therefore indicate that nph1 and npl1 show partially overlapping functions in two different responses, phototropism and chloroplast relocation, in a fluence rate-dependent manner.

Influence of environmental temperature and light intensity on growth performance and blood physiological parameters of broilers grown to heavy weight

USDA-ARS?s Scientific Manuscript database

In a study of temperature and light intensity, 9 treatments consisted of 3 levels (Low=15.6, Moderate=21.1, High=26.7 °C) of temperatures and 3 levels (0.5, 3.0, 20 lx) of light intensities from d 8 to 56 d of age. Across all light levels at d 56, broilers subjected to high temperature significantly...

Laryngeal Aerodynamics in Healthy Older Adults and Adults With Parkinson's Disease.

PubMed

Matheron, Deborah; Stathopoulos, Elaine T; Huber, Jessica E; Sussman, Joan E

2017-03-01

The present study compared laryngeal aerodynamic function of healthy older adults (HOA) to adults with Parkinson's disease (PD) while speaking at a comfortable and increased vocal intensity. Laryngeal aerodynamic measures (subglottal pressure, peak-to-peak flow, minimum flow, and open quotient [OQ]) were compared between HOAs and individuals with PD who had a diagnosis of hypophonia. Increased vocal intensity was elicited via monaurally presented multitalker background noise. At a comfortable speaking intensity, HOAs and individuals with PD produced comparable vocal intensity, rates of vocal fold closure, and minimum flow. HOAs used smaller OQs, higher subglottal pressure, and lower peak-to-peak flow than individuals with PD. Both groups increased speaking intensity when speaking in noise to the same degree. However, HOAs produced increased intensity with greater driving pressure, faster vocal fold closure rates, and smaller OQs than individuals with PD. Monaural background noise elicited equivalent vocal intensity increases in HOAs and individuals with PD. Although both groups used laryngeal mechanisms as expected to increase sound pressure level, they used these mechanisms to different degrees. The HOAs appeared to have better control of the laryngeal mechanism to make changes to their vocal intensity.

Method and apparatus for optical temperature measurements

DOEpatents

Angel, S.M.; Hirschfeld, T.B.

1986-04-22

A method and apparatus are provided for remotely monitoring temperature. Both method and apparatus employ a temperature probe material having an excitation-dependent emission line whose fluorescence intensity varies directly with temperature whenever excited by light having a first wavelength and whose fluorescence intensity varies inversely with temperature whenever excited by light having a second wavelength. Temperature is measured by alternatively illiminating the temperature probe material with light having the first wavelength and light having the second wavelength, monitoring the intensity of the successive emissions of the excitation-dependent emission line, and relating the intensity ratio of successive emissions to temperature. 3 figs.

Method and apparatus for optical temperature measurements

DOEpatents

Angel, S. Michael; Hirschfeld, Tomas B.

1988-01-01

A method and apparatus are provided for remotely monitoring temperature. Both method and apparatus employ a temperature probe material having an excitation-dependent emission line whose fluorescence intensity varies directly with temperature whenever excited by light having a first wavelength and whose fluorescence intensity varies inversely with temperature whenever excited by light having a second wavelength. Temperature is measured by alternatively illuminating the temperature probe material with light having the first wavelength and light having the second wavelength, monitoring the intensity of the successive emissions of the excitation-dependent emission line, and relating the intensity ratio of successive emissions to temperature.

Center-to-limb variation of intensity and polarization in continuum spectra of FGK stars for spherical atmospheres

NASA Astrophysics Data System (ADS)

Kostogryz, N. M.; Milic, I.; Berdyugina, S. V.; Hauschildt, P. H.

2016-02-01

Aims: One of the necessary parameters needed for the interpretation of the light curves of transiting exoplanets or eclipsing binary stars (as well as interferometric measurements of a star or microlensing events) is how the intensity and polarization of light changes from the center to the limb of a star. Scattering and absorption processes in the stellar atmosphere affect both the center-to-limb variation of intensity (CLVI) and polarization (CLVP). In this paper, we present a study of the CLVI and CLVP in continuum spectra, taking into consideration the different contributions of scattering and absorption opacity for a variety of spectral type stars with spherical atmospheres. Methods: We solve the radiative transfer equation for polarized light in the presence of a continuum scattering, taking into consideration the spherical model of a stellar atmosphere. To cross-check our results, we developed two independent codes that are based on Feautrier and short characteristics methods, respectively, Results: We calculate the center-to-limb variation of intensity (CLVI) and polarization (CLVP) in continuum for the Phoenix grid of spherical stellar model atmospheres for a range of effective temperatures (4000-7000 K), gravities (log g = 1.0-5.5), and wavelengths (4000-7000 Å), which are tabulated and available at the CDS. In addition, we present several tests of our codes and compare our calculations for the solar atmosphere with published photometric and polarimetric measurements. We also show that our two codes provide similar results in all considered cases. Conclusions: For sub-giant and dwarf stars (log g = 3.0-4.5), the lower gravity and lower effective temperature of a star lead to higher limb polarization of the star. For giant and supergiant stars (log g = 1.0-2.5), the highest effective temperature yields the largest polarization. By decreasing the effective temperature of a star down to 4500-5500 K (depending on log g), the limb polarization decreases and reaches a local minimum. It increases again with a corresponding decrease in temperature down to 4000 K. For the most compact dwarf stars (log g = 5.0-5.5), the limb polarization degree shows a maximum for models with effective temperatures in the range 4200-4600 K (depending on log g) and decreases toward higher and lower temperatures. The intensity and polarization profiles are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/586/A87

The influence of reduced light intensity on the response of benthic diatoms to herbicide exposure.

PubMed

Wood, Rebecca J; Mitrovic, Simon M; Lim, Richard P; Kefford, Ben J

2016-09-01

Herbicide pollution events in aquatic ecosystems often coincide with increased turbidity and reduced light intensity. It is therefore important to determine whether reduced light intensity can influence herbicide toxicity, especially to primary producers such as benthic diatoms. Benthic diatoms collected from 4 rivers were exposed to herbicides in 48 h rapid toxicity tests under high light (100 µmol m(-2)  s(-1) ) and low light (20 µmol m(-2)  s(-1) ) intensities. The effects of 2 herbicides (atrazine and glyphosate) were assessed on 26 freshwater benthic diatom taxa. There was no significant interaction of light and herbicide effects at the community level or on the majority (22 of 26) of benthic diatom taxa. This indicates that low light levels will likely have only a minor influence on the response of benthic diatoms to herbicides. Environ Toxicol Chem 2016;35:2252-2260. © 2016 SETAC. © 2016 SETAC.

A method to eliminate the influence of incident light variations in spectral analysis

NASA Astrophysics Data System (ADS)

Luo, Yongshun; Li, Gang; Fu, Zhigang; Guan, Yang; Zhang, Shengzhao; Lin, Ling

2018-06-01

The intensity of the light source and consistency of the spectrum are the most important factors influencing the accuracy in quantitative spectrometric analysis. An efficient "measuring in layer" method was proposed in this paper to limit the influence of inconsistencies in the intensity and spectrum of the light source. In order to verify the effectiveness of this method, a light source with a variable intensity and spectrum was designed according to Planck's law and Wien's displacement law. Intra-lipid samples with 12 different concentrations were prepared and divided into modeling sets and prediction sets according to different incident lights and solution concentrations. The spectra of each sample were measured with five different light intensities. The experimental results showed that the proposed method was effective in eliminating the influence caused by incident light changes and was more effective than normalized processing.

Fluorescent optical position sensor

DOEpatents

Weiss, Jonathan D.

2005-11-15

A fluorescent optical position sensor and method of operation. A small excitation source side-pumps a localized region of fluorescence at an unknown position along a fluorescent waveguide. As the fluorescent light travels down the waveguide, the intensity of fluorescent light decreases due to absorption. By measuring with one (or two) photodetectors the attenuated intensity of fluorescent light emitted from one (or both) ends of the waveguide, the position of the excitation source relative to the waveguide can be determined by comparing the measured light intensity to a calibrated response curve or mathematical model. Alternatively, excitation light can be pumped into an end of the waveguide, which generates an exponentially-decaying continuous source of fluorescent light along the length of the waveguide. The position of a photodetector oriented to view the side of the waveguide can be uniquely determined by measuring the intensity of the fluorescent light emitted radially at that location.

Effects of laryngoscope handle light source on the light intensity from disposable laryngoscope blades.

PubMed

Milne, A D; Brousseau, P A; Brousseau, C A

2014-12-01

A bench-top study was performed to assess the effects of different laryngoscope handles on the light intensity delivered from disposable metal or plastic laryngoscope blades. The light intensity from both the handle light sources themselves and the combined handle and laryngoscope blade sets was measured using a custom-designed testing system and light meter. Five samples of each disposable blade type were tested and compared with a standard re-usable stainless steel blade using three different handle/light sources (Vital Signs LED, Heine 2.5 V Xenon and 3.5 V Xenon). The light intensity delivered by the disposable blades ranged from 790 to 3846 lux for the different handle types. Overall, the 3.5 V Heine handle delivered the highest light output (p < 0.007) in comparison with the other handles. For the disposable blades, the overall light output was significantly higher from the plastic than the metal blades (p < 0.001). © 2014 The Association of Anaesthetists of Great Britain and Ireland.

[Effect of light intensity on the growth and digestive enzyme activity of juvenile sea cucumber Apostichopus japonicas under two kinds of culture methods].

PubMed

Wei, Zi-Zhong; Zhao, Wen

2014-01-01

The effects of light intensity (0, 1000, 2000 and 3000 1x) on the growth and digestive enzyme activity of juvenile sea cucumber Apostichopus japonicus under two kinds of culture methods (compound Chinese medicine preparation and microbial preparation) were studied. Results showed that the relative mass gain rate (WGR) and the specific growth rate (SGR) of juvenile sea cucumber were significantly affected by light intensity (P < 0.05) , and the orders of WGR and SGR (form high to low) of juvenile sea cucumber under different light intensities were 2000 1x > 1000 1x > 3000 1x > 0 1x. Under the same light intensity, the growth of juvenile sea cucumber under the two kinds of culture methods were significantly different (P < 0.05), with the WGR and SGR of the Chinese medicine treatment being greater than those of the microbial treatment. The light intensity also significantly affected the digestive enzyme activity of juvenile sea cucumber. The order of amylase and lipase activity was 2000 1x > 1000 1x > 3000 1x > 0 1x, while that of protease activity was 1000 1x > 2000 1x > 0 1x > 3000 1x. Under the same light intensity, the digestive enzyme activities of the Chinese medicine treatment were generally higher than those of the microbial treatment.

The effect of infection-control barriers on the light intensity of light-cure units and depth of cure of composite.

PubMed

Hodson, Nicholas A; Dunne, Stephen M; Pankhurst, Caroline L

2005-04-01

Dental curing lights are vulnerable to contamination with oral fluids during routine intra-oral use. This controlled study aimed to evaluate whether or not disposable transparent barriers placed over the light-guide tip would affect light output intensity or the subsequent depth of cure of a composite restoration. The impact on light intensity emitted from high-, medium- and low-output light-cure units in the presence of two commercially available disposable infection-control barriers was evaluated against a no-barrier control. Power density measurements from the three intensity light-cure units were recorded with a radiometer, then converted to a digital image using an intra-oral camera and values determined using a commercial computer program. For each curing unit, the measurements were repeated on ten separate occasions with each barrier and the control. Depth of cure was evaluated using a scrape test in a natural tooth model. At each level of light output, the two disposable barriers produced a significant reduction in the mean power density readings compared to the no-barrier control (P<0.005). The cure sleeve inhibited light output to a greater extent than either the cling film or the control (P<0.005). Only composite restorations light-activated by the high level unit demonstrated a small but significant decrease in the depth of cure compared to the control (P<0.05). Placing disposable barriers over the light-guide tip reduced the light intensity from all three curing lights. There was no impact on depth of cure except for the high-output light, where a small decrease in cure depth was noted but this was not considered clinically significant. Disposable barriers can be recommended for use with light-cure lights.

Dependence of anti-Stokes/Stokes intensity ratios on substrate optical properties for Brillouin light scattering from ultrathin iron films

NASA Astrophysics Data System (ADS)

Cochran, J. F.; From, M.; Heinrich, B.

1998-06-01

Brillouin light scattering experiments have been used to investigate the intensity of 5145 Å laser light backscattered from spin waves in 20 monolayer thick Fe(001) films. The experiments have shown that the ratio of frequency upshifted light intensity to frequency downshifted light intensity depends upon the material of the substrate used to support the iron films. For a fixed magnetic field and for a fixed angle of incidence of the laser light this intensity ratio is much larger for an iron film deposited on a sulphur passivated GaAs(001) substrate than for an iron film deposited on a Ag(001) substrate. The data have been compared with a calculation that takes into account multiple scattering of the optical waves in the iron film and in a protective gold overlayer. The observations are in qualitative agreement with the theory, except for angles of incidence greater than 60°.

Effects of forward and backward transitions in light intensities in tau-illuminance curves of the rat motor activity rhythm under constant dim light.

PubMed

Cambras, Trinitat; Díez-Noguera, Antoni

2012-07-01

Circadian rhythms are strongly influenced by light intensity, the effects of which may persist beyond the duration of light exposure (aftereffects). Here, the authors constructed period-illuminance curves for the motor activity circadian rhythm of male and female rats by recording the effects of a series of small upward and downward steps in light intensity (illuminance ranging between .01 lux of dim red light and 1 lux of white light) on their activity. In all cases, stepwise changes were made in five logarithmic steps (irradiance: dim red light: .692 µW/cm(2) and white light: .006, .016, .044, .12, and .315 µW/cm(2), corresponding, respectively, to .02, .05, .14, .13, and 1 lux measured at cage level), with changes in intensity every 2 wks. One group of rats (DLD) started in dim red light, moved up to 1 lux white light, and then back down to the original light intensity. Another group (LDL) started at 1 lux, moved down to .01 lux, and then back up to the original intensity. Motor activity data were recorded throughout the experiment and tau values, the percentage of variance explained by the rhythm, and the mean motor activity for each stage and group were calculated. The results show differences in the dynamics of tau values between the DLD and LDL groups and between males and females. In the LDL group, the tau values of both males and females were dependent on light intensity, and were similar for the forward and backward transitions. In other words, no aftereffects were found, and no differences were detected between males and females. In the DLD group, however, differences were found between males and females. Males had a tau value of 24 h 20 min under dim red light, 25 h 40 min under 1 lux, and 24 h 50 min on return to dim red light. It is noticeable that the tau values of the backward branch of the illuminance curve contradicted classical predictions, since at .38 and .14 lux the tau values were shorter than those found under the same intensities after exposure to 1 lux. Females became arrhythmic at 1 lux, and only one half of them recovered their circadian rhythm at .02 lux. The other one half remained arrhythmic even under dim red light. Thus, some of the results of this paper contradict the predictions of standard descriptions of the functioning of the circadian clock, possibly due to the effects of dim light.

Ammonium removal using algae-bacteria consortia: the effect of ammonium concentration, algae biomass, and light.

PubMed

Jia, Huijun; Yuan, Qiuyan

2018-04-01

In this study, the effects of ammonium nitrogen concentration, algae biomass concentration, and light conditions (wavelength and intensity) on the ammonium removal efficiency of algae-bacteria consortia from wastewater were investigated. The results indicated that ammonium concentration and light intensity had a significant impact on nitrification. It was found that the highest ammonia concentration (430 mg N/L) in the influent resulted in the highest ammonia removal rate of 108 ± 3.6 mg N/L/days, which was two times higher than the influent with low ammonia concentration (40 mg N/L). At the lowest light intensity of 1000 Lux, algae biomass concentration, light wavelength, and light cycle did not show a significant effect on the performance of algal-bacterial consortium. Furthermore, the ammonia removal rate was approximately 83 ± 1.0 mg N/L/days, which was up to 40% faster than at the light intensity of 2500 Lux. It was concluded that the algae-bacteria consortia can effectively remove nitrogen from wastewater and the removal performance can be stabilized and enhanced using the low light intensity of 1000 Lux that is also a cost-effective strategy.

High intensity multi beam design of SANS instrument for Dhruva reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abbas, Sohrab, E-mail: abbas@barc.gov.in; Aswal, V. K.; Désert, S.

A new and versatile design of Small Angle Neutron Scattering (SANS) instrument based on utilization of multi-beam is presented. The multi-pinholes and multi-slits as SANS collimator for medium flux Dhruva rearctor have been proposed and their designs have been validated using McStas simulations. Various instrument configurations to achieve different minimum wave vector transfers in scattering experiments are envisioned. These options enable smooth access to minimum wave vector transfers as low as ~ 6×10{sup −4} Å{sup −1} with a significant improvement in neutron intensity, allowing faster measurements. Such angularly well defined and intense neutron beam will allow faster SANS studies ofmore » agglomerates larger than few tens of nm.« less

Experimental effective intensity of steady and flashing light emitting diodes for aircraft anti-collision lighting.

DOT National Transportation Integrated Search

2013-08-01

Research was conducted to determine the effective intensity of flashing lights that incorporate light-emitting diodes (LEDs). LEDs require less power and have the ability to flash without the addition of moving parts. Compared with incandescent bulbs...

Northern Red Oak Seedling Growth Varies by Light Intensity and Seed Source

Treesearch

Charles E. McGee

1968-01-01

Northern red oak seedlings from each of three seed sources were subjected for one growing season to one of four intensities of light: full light, 70 percent light, 37 percent light, and 8 percent light. Seedlings grown in the open were taller than those grown in the shade and had more, generally heavier leaves. Height and leaf growth decreased as the amount of light...

Optical Riblet Sensor: Beam Parameter Requirements for the Probing Laser Source.

PubMed

Tschentscher, Juliane; Hochheim, Sven; Brüning, Hauke; Brune, Kai; Voit, Kay-Michael; Imlau, Mirco

2016-03-30

Beam parameters of a probing laser source in an optical riblet sensor are studied by considering the high demands on a sensors' precision and reliability for the determination of deviations of the geometrical shape of a riblet. Mandatory requirements, such as minimum intensity and light polarization, are obtained by means of detailed inspection of the optical response of the riblet using ray and wave optics; the impact of wavelength is studied. Novel measures for analyzing the riblet shape without the necessity of a measurement with a reference sample are derived; reference values for an ideal riblet structure obtained with the optical riblet sensor are given. The application of a low-cost, frequency-doubled Nd:YVO₄ laser pointer sufficient to serve as a reliable laser source in an appropriate optical riblet sensor is discussed.

Optical Riblet Sensor: Beam Parameter Requirements for the Probing Laser Source

PubMed Central

Tschentscher, Juliane; Hochheim, Sven; Brüning, Hauke; Brune, Kai; Voit, Kay-Michael; Imlau, Mirco

2016-01-01

Beam parameters of a probing laser source in an optical riblet sensor are studied by considering the high demands on a sensors’ precision and reliability for the determination of deviations of the geometrical shape of a riblet. Mandatory requirements, such as minimum intensity and light polarization, are obtained by means of detailed inspection of the optical response of the riblet using ray and wave optics; the impact of wavelength is studied. Novel measures for analyzing the riblet shape without the necessity of a measurement with a reference sample are derived; reference values for an ideal riblet structure obtained with the optical riblet sensor are given. The application of a low-cost, frequency-doubled Nd:YVO4 laser pointer sufficient to serve as a reliable laser source in an appropriate optical riblet sensor is discussed. PMID:27043567

Comparisons of luminaires: Efficacies and system design

NASA Technical Reports Server (NTRS)

Albright, L. D.; Both, A. J.

1994-01-01

Lighting designs for architectural (aesthetic) purposes, vision and safety, and plant growth have many features in common but several crucial ones that are not. The human eye is very sensitive to the color (wavelength) of light, whereas plants are less so. There are morphological reactions, particularly to the red and blue portions of the light spectrum but, in general, plants appear to accept and use light for photosynthesis everywhere over the PAR region of the spectrum. In contrast, the human eye interprets light intensity on a logarithmic scale, making people insensitive to significant differences of light intensity. As a rough rule, light intensity must change by 30 to 50% for the human eye to recognize the difference. Plants respond much more linearly to light energy, at least at intensities below photosynthetic saturation. Thus, intensity differences not noticeable to the human eye can have significant effects on total plant growth and yield, and crop timing. These factors make luminaire selection and lighting system design particularly important when designing supplemental lighting systems for plant growth. Supplemental lighting for plant growth on the scale of commercial greenhouses is a relatively expensive undertaking. Light intensities are often much higher than required for task (vision) lighting, which increases both installation and operating costs. However, and especially in the northern regions of the United States (and Canada, Europe, etc.), supplemental lighting during winter may be necessary to produce certain crops (e.g., tomatoes) and very useful to achieve full plant growth potential and crop timing with most other greenhouse crops. Operating costs over the life of a luminaire typically will exceed the initial investment, making lighting efficacy a major consideration. This report reviews tests completed to evaluate the efficiencies of various commercially-available High-Pressure Sodium luminaires, and then describes the results of using a commercial lighting design computer program, Lumen-Micro, to explore how to place luminaires within greenhouses and plant growth chambers to achieve light (PAR) uniformity and relatively high lighting efficacies. Several suggestions are presented which could encourage systematic design of plant lighting systems.

Changes in pigment, spectral transmission and element content of pink chicken eggshells with different pigment intensity during incubation.

PubMed

Yu, Yue; Li, Zhanming; Pan, Jinming

2016-01-01

Objective. The objective of this study was to investigate changes in pigment, spectral transmission and element content of chicken eggshells with different intensities of pink pigment during the incubation period. We also investigated the effects of the region (small pole, equator and large pole) and pink pigment intensity of the chicken eggshell on the percent transmission of light passing through the chicken eggshells. Method. Eggs of comparable weight from a meat-type breeder (Meihuang) were used, and divided based on three levels of pink pigment (light, medium and dark) in the eggshells. During the incubation (0-21 d), the values of the eggshell pigment (ΔE, L (∗), a (∗), b (∗)) were measured. The percent transmission of light for different regions and intensities of eggshell pigmentation was measured by using the visible wavelength range of 380-780 nm. Result. Three measured indicators of eggshell color, ΔE, L (∗) and a (∗), did not change significantly during incubation. Compared with other regions and pigment intensities, eggshell at the small pole and with light pigmentation intensity showed the highest percent transmission of light. The transmission value varied significantly (P < 0.001) with incubation time. The element analysis of eggshells with different levels of pink pigment showed that the potassium content of the eggshells for all pigment levels decreased significantly during incubation. Conclusion. In summary, pigment intensity and the region of the eggshell influenced the percent transmission of light of eggshell. Differences in the spectral characteristics of different eggshells may influence the effects of photostimulation during the incubation of eggs. All of these results will be applicable for perfecting the design of light intensity for lighted incubation to improve productivity.

Changes in pigment, spectral transmission and element content of pink chicken eggshells with different pigment intensity during incubation

PubMed Central

Yu, Yue; Li, Zhanming

2016-01-01

Objective. The objective of this study was to investigate changes in pigment, spectral transmission and element content of chicken eggshells with different intensities of pink pigment during the incubation period. We also investigated the effects of the region (small pole, equator and large pole) and pink pigment intensity of the chicken eggshell on the percent transmission of light passing through the chicken eggshells. Method. Eggs of comparable weight from a meat-type breeder (Meihuang) were used, and divided based on three levels of pink pigment (light, medium and dark) in the eggshells. During the incubation (0–21 d), the values of the eggshell pigment (ΔE, L∗, a∗, b∗) were measured. The percent transmission of light for different regions and intensities of eggshell pigmentation was measured by using the visible wavelength range of 380–780 nm. Result. Three measured indicators of eggshell color, ΔE, L∗ and a∗, did not change significantly during incubation. Compared with other regions and pigment intensities, eggshell at the small pole and with light pigmentation intensity showed the highest percent transmission of light. The transmission value varied significantly (P < 0.001) with incubation time. The element analysis of eggshells with different levels of pink pigment showed that the potassium content of the eggshells for all pigment levels decreased significantly during incubation. Conclusion. In summary, pigment intensity and the region of the eggshell influenced the percent transmission of light of eggshell. Differences in the spectral characteristics of different eggshells may influence the effects of photostimulation during the incubation of eggs. All of these results will be applicable for perfecting the design of light intensity for lighted incubation to improve productivity. PMID:27019785

Influence of light intensity and water content of medium on total dendrobine of Dendrobium nobile Lindl.

PubMed

Li, Jin-Ling; Zhao, Zhi; Liu, Hong-Chang; Luo, Chun-Li; Wang, Hua-Lei

2017-11-01

To ascertain the influence of light intensity and water content of medium on the total dendrobine of Dendrobium nobile (D. nobile). The principal component analysis combined with total dendrobine accumulation was conducted to assess the yield and quality of D. nobile in all treatments. In the experiment, D. nobile plants were cultivated in greenhouse as tested materials, and complete test of 9 treatments was adopted with relative light intensities 75.02%, 39.74%, 29.93% and relative water content of medium 50%, 65%, 80%. The plants were treated in June and harvested till December. Indexes including agronomic traits, fresh weight and dry weight of stem and leaf, ash content, extract, and dendrobine were measured. Under the light intensity treatments of 75.02% with 50%, 65%, 80% water content of medium, the basal stems of plants were comparatively thicker with more leaves, and the fresh weight and dry weight of stems and leaves were significantly higher than other 6 treatments. Leaves in all treatments contained dendrobine. Under the light intensity treatments of 75.02% with 50%, 65%, 80% water content of medium, dendrobine content of leaves was lower while dendrobine contents of other treatments were more than 0.60%. After comprehensive assessment through the principal component analysis and total dendrobine accumulation, the results showed that 3 treatments with relative light intensity of 75.02% ranked the top three. In brief, the moderately strong light intensity and water content of medium from low to medium can facilitate the growth and yield of D. nobile plants, while light intensity from moderately weak to weak can enhance the dendrobine content. Copyright © 2017 Hainan Medical University. Production and hosting by Elsevier B.V. All rights reserved.

Technique for compressing light intensity ranges utilizing a specifically designed liquid crystal notch filter

DOEpatents

Rushford, Michael C.

1988-01-01

A pin hole camera assembly for use in viewing an object having a relatively large light intensity range, for example a crucible containing molten metal in an atomic vapor laser isotope separation (AVLIS) system is disclosed herein. The assembly includes means for optically compressing the light intensity range appearing at its input sufficient to make it receivable and decipherable by a standard video camera. To accomplish this, the assembly utilizes the combination of interference filter and a liquid crystal notch filter. The latter which preferably includes a cholesteric liquid crystal arrangement is configured to pass light at all wavelengths, except a relatively narrow wavelength band which defines the filter's notch, and includes means for causing the notch to vary to at least a limited extent with the intensity of light at its light incidence surface.

Apparatus and process for active pulse intensity control of laser beam

DOEpatents

Wilcox, Russell B.

1992-01-01

An optically controlled laser pulse energy control apparatus and process is disclosed wherein variations in the energy of a portion of the laser beam are used to vary the resistance of a photodetector such as a photoresistor through which a control voltage is fed to a light intensity controlling device through which a second portion of the laser beam passes. Light attenuation means are provided to vary the intensity of the laser light used to control the resistance of the photodetector. An optical delay path is provided through which the second portion of the beam travels before reaching the light intensity controlling device. The control voltage is supplied by a variable power supply. The apparatus may be tuned to properly attenuate the laser beam passing through the intensity controlling device by adjusting the power supply, the optical delay path, or the light attenuating means.

Light history modulates antioxidant and photosynthetic responses of biofilms to both natural (light) and chemical (herbicides) stressors.

PubMed

Bonnineau, Chloé; Sague, Irene Gallardo; Urrea, Gemma; Guasch, Helena

2012-05-01

In multiple stress situations, the co-occurrence of environmental and chemical factors can influence organisms' ability to cope with toxicity. In this context, the influence of light adaptation on the response of freshwater biofilms to sudden light changes or to herbicides exposure was investigated by determining various parameters: diatom community composition, photosynthetic parameters, chlorophyll a content, antioxidant enzyme activities. Biofilms were grown in microcosms under sub-optimal, saturating, and high light intensities and showed already described characteristics of shade/light adaptation (community structure, photosynthetic adaptation, etc.). Light history modulated antioxidant and photosynthetic responses of biofilms to the stress caused by short-term exposure to sudden light changes or to herbicides. First biofilms adapted to sub-optimal light intensity (shade-adapted) were found to be more sensitive to an increase in light intensity than high-light adapted ones to a reduction in light intensity. Second, while light history influenced biofilms' response to glyphosate, it had little influence on biofilms' response to copper and none on its response to oxyfluorfen. Indeed glyphosate exposure led to a stronger decrease in photosynthetic efficiency of shade-adapted biofilms (EC(50) = 11.7 mg L(-1)) than of high-light adapted communities (EC(50) = 35.6 mg L(-1)). Copper exposure led to an activation of ascorbate peroxidase (APX) in biofilms adapted to sub-optimal and saturating light intensity while the protein content decreased in all biofilms exposed to copper. Oxyfluorfen toxicity was independent of light history provoking an increase in APX activity. In conclusion this study showed that both previous exposure to contaminants and physical habitat characteristics might influence community tolerance to disturbances strongly.

Effects of GPS sampling intensity on home range analyses

Treesearch

Jeffrey J. Kolodzinski; Lawrence V. Tannenbaum; David A. Osborn; Mark C. Conner; W. Mark Ford; Karl V. Miller

2010-01-01

The two most common methods for determining home ranges, minimum convex polygon (MCP) and kernel analyses, can be affected by sampling intensity. Despite prior research, it remains unclear how high-intensity sampling regimes affect home range estimations. We used datasets from 14 GPS-collared, white-tailed deer (Odocoileus virginianus) to describe...

An air flow sensor for neonatal mechanical ventilation applications based on a novel fiber-optic sensing technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Battista, L.; Sciuto, S. A.; Scorza, A.

2013-03-15

In this work, a simple and low-cost air flow sensor, based on a novel fiber-optic sensing technique has been developed for monitoring air flows rates supplied by a neonatal ventilator to support infants in intensive care units. The device is based on a fiber optic sensing technique allowing (a) the immunity to light intensity variations independent by measurand and (b) the reduction of typical shortcomings affecting all biomedical fields (electromagnetic interference and patient electrical safety). The sensing principle is based on the measurement of transversal displacement of an emitting fiber-optic cantilever due to action of air flow acting on it;more » the fiber tip displacement is measured by means of a photodiode linear array, placed in front of the entrance face of the emitting optical fiber in order to detect its light intensity profile. As the measurement system is based on a detection of the illumination pattern, and not on an intensity modulation technique, it results less sensitive to light intensity fluctuation independent by measurand than intensity-based sensors. The considered technique is here adopted in order to develop two different configurations for an air flow sensor suitable for the measurement of air flow rates typically occurring during mechanical ventilation of newborns: a mono-directional and a bi-directional transducer have been proposed. A mathematical model for the air flow sensor is here proposed and a static calibration of two different arrangements has been performed: a measurement range up to 3.00 Multiplication-Sign 10{sup -4} m{sup 3}/s (18.0 l/min) for the mono-directional sensor and a measurement range of {+-}3.00 Multiplication-Sign 10{sup -4} m{sup 3}/s ({+-}18.0 l/min) for the bi-directional sensor are experimentally evaluated, according to the air flow rates normally encountered during tidal breathing of infants with a mass lower than 10 kg. Experimental data of static calibration result in accordance with the proposed theoretical model: for the mono-directional configuration, the coefficient of determination r{sup 2} is equal to 0.997; for the bi-directional configuration, the coefficient of determination r{sup 2} is equal to 0.990 for positive flows (inspiration) and 0.988 for negative flows (expiration). Measurement uncertainty {delta}Q of air flow rate has been evaluated by means of the propagation of distributions and the percentage error in the arrangement of bi-directional sensor ranges from a minimum of about 0.5% at -18.0 l/min to a maximum of about 9% at -12.0 l/min.« less

Individuals underestimate moderate and vigorous intensity physical activity.

PubMed

Canning, Karissa L; Brown, Ruth E; Jamnik, Veronica K; Salmon, Art; Ardern, Chris I; Kuk, Jennifer L

2014-01-01

It is unclear whether the common physical activity (PA) intensity descriptors used in PA guidelines worldwide align with the associated percent heart rate maximum method used for prescribing relative PA intensities consistently between sexes, ethnicities, age categories and across body mass index (BMI) classifications. The objectives of this study were to determine whether individuals properly select light, moderate and vigorous intensity PA using the intensity descriptions in PA guidelines and determine if there are differences in estimation across sex, ethnicity, age and BMI classifications. 129 adults were instructed to walk/jog at a "light," "moderate" and "vigorous effort" in a randomized order. The PA intensities were categorized as being below, at or above the following %HRmax ranges of: 50-63% for light, 64-76% for moderate and 77-93% for vigorous effort. On average, people correctly estimated light effort as 51.5±8.3%HRmax but underestimated moderate effort as 58.7±10.7%HRmax and vigorous effort as 69.9±11.9%HRmax. Participants walked at a light intensity (57.4±10.5%HRmax) when asked to walk at a pace that provided health benefits, wherein 52% of participants walked at a light effort pace, 19% walked at a moderate effort and 5% walked at a vigorous effort pace. These results did not differ by sex, ethnicity or BMI class. However, younger adults underestimated moderate and vigorous intensity more so than middle-aged adults (P<0.05). When the common PA guideline descriptors were aligned with the associated %HRmax ranges, the majority of participants underestimated the intensity of PA that is needed to obtain health benefits. Thus, new subjective descriptions for moderate and vigorous intensity may be warranted to aid individuals in correctly interpreting PA intensities.

The role of low light intensity: A step towards understanding the connection between light, optic/lens and photovoltaic behavior for Sb2S3 thin-film solar cells

NASA Astrophysics Data System (ADS)

Lojpur, Vesna; Mitrić, Miodrag; Validžić, Ivana Lj

2018-05-01

We report here an optic/lens system that we used so far, for cooling the surface of solar cells, the reduction of light intensity and the change of light distribution that reaches the surface of the solar cell. The objective was to improve photovoltaic characteristics under very low light illumination, as well as to understand the connection between light, optic/lens and photovoltaic behavior for Sb2S3 thin-film solar cells. It was found that for all so far designed thin-film solar cells made and based on the synthesized Sb2S3, optics/lens system causes an increase in open circuit voltage (VOC) and short circuit current (ISC) and thus the efficiencies of made solar devices. Values of energy gaps for the thin-films made devices were in the range from 1.4 to 2 eV. Improvements of the photovoltaic response of the designed devices are found to be better at the lower light intensity (5% sun), than at higher intensities of light. For the same intensity of light used optic/lens improves the efficiency of the devices, by changing the light distribution. Other processes that are related to the optics/lens system, leading to an increase in ISC and VOC and consequently to an increase in efficiencies of the designed devices, are investigated.

Arabidopsis nph1 and npl1: Blue light receptors that mediate both phototropism and chloroplast relocation

PubMed Central

Sakai, Tatsuya; Kagawa, Takatoshi; Kasahara, Masahiro; Swartz, Trevor E.; Christie, John M.; Briggs, Winslow R.; Wada, Masamitsu; Okada, Kiyotaka

2001-01-01

UV-A/blue light acts to regulate a number of physiological processes in higher plants. These include light-driven chloroplast movement and phototropism. The NPH1 gene of Arabidopsis encodes an autophosphorylating protein kinase that functions as a photoreceptor for phototropism in response to low-intensity blue light. However, nph1 mutants have been reported to exhibit normal phototropic curvature under high-intensity blue light, indicating the presence of an additional phototropic receptor. A likely candidate is the nph1 homologue, npl1, which has recently been shown to mediate the avoidance response of chloroplasts to high-intensity blue light in Arabidopsis. Here we demonstrate that npl1, like nph1, noncovalently binds the chromophore flavin mononucleotide (FMN) within two specialized PAS domains, termed LOV domains. Furthermore, when expressed in insect cells, npl1, like nph1, undergoes light-dependent autophosphorylation, indicating that npl1 also functions as a light receptor kinase. Consistent with this conclusion, we show that a nph1npl1 double mutant exhibits an impaired phototropic response under both low- and high-intensity blue light. Hence, npl1 functions as a second phototropic receptor under high fluence rate conditions and is, in part, functionally redundant to nph1. We also demonstrate that both chloroplast accumulation in response to low-intensity light and chloroplast avoidance movement in response to high-intensity light are lacking in the nph1npl1 double mutant. Our findings therefore indicate that nph1 and npl1 show partially overlapping functions in two different responses, phototropism and chloroplast relocation, in a fluence rate-dependent manner. PMID:11371609

Effects of temperature and salinity on light scattering by water

NASA Astrophysics Data System (ADS)

Zhang, Xiaodong; Hu, Lianbo

2010-04-01

A theoretical model on light scattering by water was developed from the thermodynamic principles and was used to evaluate the effects of temperature and salinity. The results agreed with the measurements by Morel within 1%. The scattering increases with salinity in a non-linear manner and the empirical linear model underestimate the scattering by seawater for S < 40 psu. Seawater also exhibits an 'anomalous' scattering behavior with a minimum occurring at 24.64 °C for pure water and this minimum increases with the salinity, reaching 27.49 °C at 40 psu.

Minimum-Risk Path Finding by an Adaptive Amoebal Network

NASA Astrophysics Data System (ADS)

Nakagaki, Toshiyuki; Iima, Makoto; Ueda, Tetsuo; Nishiura, Yasumasa; Saigusa, Tetsu; Tero, Atsushi; Kobayashi, Ryo; Showalter, Kenneth

2007-08-01

When two food sources are presented to the slime mold Physarum in the dark, a thick tube for absorbing nutrients is formed that connects the food sources through the shortest route. When the light-avoiding organism is partially illuminated, however, the tube connecting the food sources follows a different route. Defining risk as the experimentally measurable rate of light-avoiding movement, the minimum-risk path is exhibited by the organism, determined by integrating along the path. A model for an adaptive-tube network is presented that is in good agreement with the experimental observations.

Piezoresistor-equipped fluorescence-based cantilever probe for near-field scanning.

PubMed

Kan, Tetsuo; Matsumoto, Kiyoshi; Shimoyama, Isao

2007-08-01

Scanning near-field optical microscopes (SNOMs) with fluorescence-based probes are promising tools for evaluating the optical characteristics of nanoaperture devices used for biological investigations, and this article reports on the development of a microfabricated fluorescence-based SNOM probe with a piezoresistor. The piezoresistor was built into a two-legged root of a 160-microm-long cantilever. To improve the displacement sensitivity of the cantilever, the piezoresistor's doped area was shallowly formed on the cantilever surface. A fluorescent bead, 500 nm in diameter, was attached to the bottom of the cantilever end as a light-intensity-sensitive material in the visible-light range. The surface of the scanned sample was simply detected by the probe's end being displaced by contact with the sample. Measuring displacements piezoresistively is advantageous because it eliminates the noise arising from the use of the optical-lever method and is free of any disturbance in the absorption or the emission spectrum of the fluorescent material at the probe tip. The displacement sensitivity was estimated to be 6.1 x 10(-6) nm(-1), and the minimum measurable displacement was small enough for near-field measurement. This probe enabled clear scanning images of the light field near a 300 x 300 nm(2) aperture to be obtained in the near-field region where the tip-sample distance is much shorter than the light wavelength. This scanning result indicates that the piezoresistive way of tip-sample distance regulation is effective for characterizing nanoaperture optical devices.

Influence of the Diadinoxanthin Pool Size on Photoprotection in the Marine Planktonic Diatom Phaeodactylum tricornutum1

PubMed Central

Lavaud, Johann; Rousseau, Bernard; van Gorkom, Hans J.; Etienne, Anne-Lise

2002-01-01

The pool size of the xanthophyll cycle pigment diadinoxanthin (DD) in the diatom Phaeodactylum tricornutum depends on illumination conditions during culture. Intermittent light caused a doubling of the DD pool without significant change in other pigment contents and photosynthetic parameters, including the photosystem II (PSII) antenna size. On exposure to high-light intensity, extensive de-epoxidation of DD to diatoxanthin (DT) rapidly caused a very strong quenching of the maximum chlorophyll fluorescence yield (Fm, PSII reaction centers closed), which was fully reversed in the dark. The non-photochemical quenching of the minimum fluorescence yield (Fo, PSII centers open) decreased the quantum efficiency of PSII proportionally. For both Fm and Fo, the non-photochemical quenching expressed as F/F′ − 1 (with F′ the quenched level) was proportional to the DT concentration. However, the quenching of Fo relative to that of Fm was much stronger than random quenching in a homogeneous antenna could explain, showing that the rate of photochemical excitation trapping was limited by energy transfer to the reaction center rather than by charge separation. The cells can increase not only the amount of DT they can produce, but also its efficiency in competing with the PSII reaction center for excitation. The combined effect allowed intermittent light grown cells to down-regulate PSII by 90% and virtually eliminated photoinhibition by saturating light. The unusually rapid and effective photoprotection by the xanthophyll cycle in diatoms may help to explain their dominance in turbulent waters. PMID:12114593

Light intensity related to stand density in mature stands of the western white pine type

Treesearch

C. A. Wellner

1948-01-01

Where tolerance of forest trees or subordinate vegetation is a factor in management, the forester needs a simple field method of Estimating or forecasting light intensities in forest stands. The following article describes a method developed for estimating light intensity beneath the canopy in western white pine forests which may have application in other types.

Effects of digital phase-conjugate light intensity on time-reversal imaging through animal tissue.

PubMed

Toda, Sogo; Kato, Yuji; Kudo, Nobuki; Shimizu, Koichi

2018-04-01

For transillumination imaging of animal tissues, we have attempted to suppress the scattering effect in a turbid medium using the time-reversal principle of phase-conjugate light. We constructed a digital phase-conjugate system to enable intensity modulation and phase modulation. Using this system, we clarified the effectiveness of the intensity information for restoration of the original light distribution through a turbid medium. By varying the scattering coefficient of the medium, we clarified the limit of time-reversal ability with intensity information of the phase-conjugate light. Experiment results demonstrated the applicability of the proposed technique to animal tissue.

Correlated photometric and polarimetric phenomena in AM Herculis

NASA Technical Reports Server (NTRS)

Priedhorsky, W. C.; Krzeminski, W.; Tapia, S.

1978-01-01

Via simultaneous multicolor photometry and polarimetry of AM Herculis, we find correlations among polarization, flux, and color in the V and I bands in periodic and nonperiodic (i.e., flickering) activity. The primary minimum observed in both bands is accompanied by a blueward shift of the (B - R) color and a decrease in the absolute value of the percent circular polarization in the V band. Outside primary minimum, peaks of flickering activity tend to be associated with an increase in the absolute value of the circular polarization and the concurrent reddening of the (B - R) and (R - I) colors. The visual light curve of AM Her can be explained by a flickering, circularly polarized light source which is obscured at primary minimum, and is redder than the total system color in the URVRI bands.

First Precision Photometric Observations and Analyses of the Totally Eclipsing, Solar Type Binary V573 Pegasi

NASA Astrophysics Data System (ADS)

Samec, R. G.; Caton, D. B.; Faulkner, D. R.

2018-06-01

CCD VRcIc light curves of V573 Peg were taken 26 and 27 September and 2, 4, and 6 October, 2017, at the Dark Sky Observatory in North Carolina with the 0.81-m reflector of Appalachian State University. Five times of minimum light were calculated, two primary and three secondary eclipses, from our present observations. The following quadratic ephemeris was determined from all available times of minimum light: JD Hel MinI = 2456876.4958 (2) d + 0.41744860 (8) × E -2.74 (12) × 10^-10 × E2, where the parentheses hold the ± error in the last two digits of the preceding value. A 14-year period study (covered by 24 times of minimum light) reveals a decreasing orbital period with high confidence, possibly due to magnetic braking. The mass ratio is found to be somewhat extreme, M2 / M1 = 0.2629 ± 0.0006 (M1 / M2 = 3.8). Its Roche Lobe fill-out is ˜25%. The solution had no need of spots. The component temperature difference is about 130 K, with the less massive component as the hotter one, so it is a W-type W UMa Binary. The inclination is 80.4 ± 0.1°. Our secondary eclipse shows a time of constant light with an eclipse duration of 24 minutes. More information is given in the following report.

Effect of light intensity on the total lipid and fatty acid composition of six strains of marine diatoms

NASA Astrophysics Data System (ADS)

Liang, Ying; Mai, Kang-Sen; Sun, Shi-Chun; Yu, Dao-Zhan

2001-09-01

The effect of light intensity (1500 lx and 5000 lx) on the total lipid and fatty acid composition of six strains of marine diatoms Cylindrotheca fusiformis (B211), Phaeodactylum tricornutum (B114, B118 and B221) Nitzschia closterium (B222) and Chaetoceros gracilis (B13) was investigated. The total lipids of B13, B114, and B211 grown at 5000 lx were lower than those grown at 1500 lx. No evident changes were observed in B118, B221 and B222. Fatty acid composition changed considerably at different light intensity although no consistent correlation between the relative proportion of a single FA and light intensity. The major fatty acids of the 6 strains were 14∶0, 16∶0, 16∶1 (n-7) and 20∶5(n-3). Cylindrotheca fusiformis had high percentage of 20∶4n 6(9.2 10.9%). The total polyunsaturated fatty acid in all 6 strains decreased with increasing light intensity. The percentage of the highly unsaturated fatty acid eicosapentaenoic acid (EPA) decreased with increasing light intensity in all strains except Chaetoceros gracilis.

Arterial carboxyhemoglobin level and outcome in critically ill patients.

PubMed

Melley, Daniel D; Finney, Simon J; Elia, Androula; Lagan, Anna L; Quinlan, Gregory J; Evans, Timothy W

2007-08-01

Arterial carboxyhemoglobin is elevated in patients with critical illness. It is an indicator of the endogenous production of carbon monoxide by the enzyme heme oxygenase, which modulates the response to oxidant stress. The objective was to explore the hypothesis that arterial carboxyhemoglobin level is associated with inflammation and survival in patients requiring cardiothoracic intensive care. Prospective, observational study. A cardiothoracic intensive care unit. All patients admitted over a 15-month period. None. Arterial carboxyhemoglobin, bilirubin, and standard biochemical, hematologic, and physiologic markers of inflammation were measured in 1,267 patients. Associations were sought between levels of arterial carboxyhemoglobin, markers of the inflammatory response, and clinical outcome. Intensive care unit mortality was associated with lower minimum and greater maximal carboxyhemoglobin levels (p < .0001 and p < .001, respectively). After adjustment for age, gender, illness severity, and other relevant variables, a lower minimum arterial carboxyhemoglobin was associated with an increased risk of death from all causes (odds risk of death, 0.391; 95% confidence interval, 0.190-0.807; p = .011). Arterial carboxyhemoglobin correlated with markers of the inflammatory response. Both low minimum and high maximum levels of arterial carboxyhemoglobin were associated with increased intensive care mortality. Although the heme oxygenase system is protective, excessive induction may be deleterious. This suggests that there may be an optimal range for heme oxygenase-1 induction.

Measurement of the intensity of the beam in the abort gap at the Tevatron utilizing synchrotron light

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thurman-Keup, R.; Lorman, E.; Meyer, T.

2005-05-01

This paper discusses the implementation of abort gap beam intensity monitoring at the Tevatron collider at Fermilab. There are two somewhat independent monitors which measure the intensity of the synchrotron light emitted by particles in the abort gaps. One system uses a gated Photomultiplier Tube (PMT) to measure the light intensity, and the other system uses a single lens telescope, gated image intensifier, and Charge Injection Device (CID) camera to image the beam.

Leisure time physical activity and mortality: a detailed pooled analysis of the dose-response relationship.

PubMed

Arem, Hannah; Moore, Steven C; Patel, Alpa; Hartge, Patricia; Berrington de Gonzalez, Amy; Visvanathan, Kala; Campbell, Peter T; Freedman, Michal; Weiderpass, Elisabete; Adami, Hans Olov; Linet, Martha S; Lee, I-Min; Matthews, Charles E

2015-06-01

The 2008 Physical Activity Guidelines for Americans recommended a minimum of 75 vigorous-intensity or 150 moderate-intensity minutes per week (7.5 metabolic-equivalent hours per week) of aerobic activity for substantial health benefit and suggested additional benefits by doing more than double this amount. However, the upper limit of longevity benefit or possible harm with more physical activity is unclear. To quantify the dose-response association between leisure time physical activity and mortality and define the upper limit of benefit or harm associated with increased levels of physical activity. We pooled data from 6 studies in the National Cancer Institute Cohort Consortium (baseline 1992-2003). Population-based prospective cohorts in the United States and Europe with self-reported physical activity were analyzed in 2014. A total of 661,137 men and women (median age, 62 years; range, 21-98 years) and 116,686 deaths were included. We used Cox proportional hazards regression with cohort stratification to generate multivariable-adjusted hazard ratios (HRs) and 95% CIs. Median follow-up time was 14.2 years. Leisure time moderate- to vigorous-intensity physical activity. The upper limit of mortality benefit from high levels of leisure time physical activity. Compared with individuals reporting no leisure time physical activity, we observed a 20% lower mortality risk among those performing less than the recommended minimum of 7.5 metabolic-equivalent hours per week (HR, 0.80 [95% CI, 0.78-0.82]), a 31% lower risk at 1 to 2 times the recommended minimum (HR, 0.69 [95% CI, 0.67-0.70]), and a 37% lower risk at 2 to 3 times the minimum (HR, 0.63 [95% CI, 0.62-0.65]). An upper threshold for mortality benefit occurred at 3 to 5 times the physical activity recommendation (HR, 0.61 [95% CI, 0.59-0.62]); however, compared with the recommended minimum, the additional benefit was modest (31% vs 39%). There was no evidence of harm at 10 or more times the recommended minimum (HR, 0.69 [95% CI, 0.59-0.78]). A similar dose-response relationship was observed for mortality due to cardiovascular disease and to cancer. Meeting the 2008 Physical Activity Guidelines for Americans minimum by either moderate- or vigorous-intensity activities was associated with nearly the maximum longevity benefit. We observed a benefit threshold at approximately 3 to 5 times the recommended leisure time physical activity minimum and no excess risk at 10 or more times the minimum. In regard to mortality, health care professionals should encourage inactive adults to perform leisure time physical activity and do not need to discourage adults who already participate in high-activity levels.

Optical-Fiber Leak Detector

NASA Technical Reports Server (NTRS)

Workman, Gary L.; Kosten, Susan E.

1994-01-01

Proposed optical-fiber sensor detects small changes in pressure in elastomeric O-ring or similar pressure seal, which may indicate deterioration of seal and interpreted as indications of incipient failure. According to concept, length of optical fiber embedded in seal. Light-emitting diode illuminates one end of fiber; photodetector measures intensity of light emerging from other end. Pressure-induced changes in seal bend fiber slightly, altering microbending-induced loss of light from fiber and alter intensity of light at photodetector. Change in intensity approximately proportional to change in pressure.

40 CFR 86.709-94 - In-use emission standards for 1994 and later model year light-duty trucks.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Model Year Light-Duty Vehicles and Light-Duty Trucks § 86.709-94 In-use emission standards for 1994 and... exhaust emissions from 1994 and later model year light light-duty trucks shall meet all standards in... standards in tables H94-9 and H94-10. (ii) For model years 1996 and 1997, a minimum of the percentages shown...

40 CFR 86.709-94 - In-use emission standards for 1994 and later model year light-duty trucks.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Model Year Light-Duty Vehicles and Light-Duty Trucks § 86.709-94 In-use emission standards for 1994 and... exhaust emissions from 1994 and later model year light light-duty trucks shall meet all standards in... standards in tables H94-9 and H94-10. (ii) For model years 1996 and 1997, a minimum of the percentages shown...

40 CFR 86.709-94 - In-use emission standards for 1994 and later model year light-duty trucks.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Model Year Light-Duty Vehicles and Light-Duty Trucks § 86.709-94 In-use emission standards for 1994 and... exhaust emissions from 1994 and later model year light light-duty trucks shall meet all standards in... standards in tables H94-9 and H94-10. (ii) For model years 1996 and 1997, a minimum of the percentages shown...

40 CFR 86.709-94 - In-use emission standards for 1994 and later model year light-duty trucks.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Model Year Light-Duty Vehicles and Light-Duty Trucks § 86.709-94 In-use emission standards for 1994 and... exhaust emissions from 1994 and later model year light light-duty trucks shall meet all standards in... standards in tables H94-9 and H94-10. (ii) For model years 1996 and 1997, a minimum of the percentages shown...

Safety of American Heart Association-recommended minimum exercise for desmosomal mutation carriers.

PubMed

Sawant, Abhishek C; Te Riele, Anneline S J M; Tichnell, Crystal; Murray, Brittney; Bhonsale, Aditya; Tandri, Harikrishna; Judge, Daniel P; Calkins, Hugh; James, Cynthia A

2016-01-01

Endurance exercise is associated with adverse outcomes in patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C). Exercise recommendations for family members remain undetermined. The purposes of this study were to determine if (1) endurance exercise (Bethesda class C) and exercise intensity (metabolic equivalent hours per year [MET-Hr/year]) increase the likelihood of fulfilling 2010 Task Force Criteria and ventricular arrhythmias/implantable cardioverter-defibrillator shock (ventricular tachycardia/ventricular fibrillation [VT/VF]), and (2) exercise restriction to the American Heart Association (AHA)-recommended minimum for healthy adults is associated with favorable outcomes of at-risk family members. Twenty-eight family members of 10 probands inheriting a PKP2 mutation were interviewed about exercise from age 10. Exercise threshold to maintain overall health was based on the 2007 AHA guidelines of a minimum 390 to 650 MET-Hr/year. After adjustment for age, sex, and family membership, both participation in endurance athletics (odds ratio [OR] 7.4, P = .03) and higher-intensity exercise (OR = 4.2, P = .004) were associated with diagnosis (n = 13). Endurance athletes were also significantly more likely to develop VT/VF (n = 6, P = .02). Family members who restricted exercise at or below the upper bound of the AHA goal (≤650 MET-Hr/year) were significantly less likely to be diagnosed (OR = 0.07, P = .002) and had no VT/VF. At diagnosis and first VT/VF, family members had accumulated 2.8-fold (P = .002) and 3.5-fold (P = .03), respectively, greater MET-Hr exercise than the AHA-recommended minimum. Those who developed VT/VF had performed particularly high-intensity exercise in adolescence compared to unaffected family members (age 10-14: P = .04; age 14-19: P = .02). The results of this study suggest restricting unaffected desmosomal mutation carriers from endurance and high-intensity athletics but potentially not from AHA-recommended minimum levels of exercise for healthy adults. Copyright © 2016 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Solar Drivers of 11-yr and Long-Term Cosmic Ray Modulation

NASA Technical Reports Server (NTRS)

Cliver, E. W.; Richardson, I. G.; Ling, A. G.

2011-01-01

In the current paradigm for the modulation of galactic cosmic rays (GCRs), diffusion is taken to be the dominant process during solar maxima while drift dominates at minima. Observations during the recent solar minimum challenge the pre-eminence of drift: at such times. In 2009, the approx.2 GV GCR intensity measured by the Newark neutron monitor increased by approx.5% relative to its maximum value two cycles earlier even though the average tilt angle in 2009 was slightly larger than that in 1986 (approx.20deg vs. approx.14deg), while solar wind B was significantly lower (approx.3.9 nT vs. approx.5.4 nT). A decomposition of the solar wind into high-speed streams, slow solar wind, and coronal mass ejections (CMEs; including postshock flows) reveals that the Sun transmits its message of changing magnetic field (diffusion coefficient) to the heliosphere primarily through CMEs at solar maximum and high-speed streams at solar minimum. Long-term reconstructions of solar wind B are in general agreement for the approx. 1900-present interval and can be used to reliably estimate GCR intensity over this period. For earlier epochs, however, a recent Be-10-based reconstruction covering the past approx. 10(exp 4) years shows nine abrupt and relatively short-lived drops of B to < or approx.= 0 nT, with the first of these corresponding to the Sporer minimum. Such dips are at variance with the recent suggestion that B has a minimum or floor value of approx.2.8 nT. A floor in solar wind B implies a ceiling in the GCR intensity (a permanent modulation of the local interstellar spectrum) at a given energy/rigidity. The 30-40% increase in the intensity of 2.5 GV electrons observed by Ulysses during the recent solar minimum raises an interesting paradox that will need to be resolved.

Low-loss bloch wave guiding in open structures and highly compact efficient waveguide-crossing arrays

DOEpatents

Popovic, Milos

2011-03-08

Low-loss waveguide structures may comprise a multimode waveguide supporting a periodic light intensity pattern, and attachments disposed at the waveguide adjacent low-intensity regions of the light intensity pattern.

Dynamic control of supplemental lighting for greenhouse

NASA Astrophysics Data System (ADS)

Wang, Yuanxv; Wei, Ruihua; Xu, Lihong

2018-04-01

The development of light-emitting diodes (LED) technology to a large extent reduce the energy consumption of greenhouse, however, the light control methods to realize the energy saving still have great potential. The aim of this paper is to develop a more efficient control method of dynamic control of the LED top-lighting (TL) intensity and the LED inter-lighting (IL) intensity for the greatest economic benefits. A dynamic lighting control algorithm (DLC) based on model is proposed, which defines the economic benefit performance criterion of the supplemental lighting control. The optimal light intensity of TL and IL is calculated in real time according to the algorithm. The simulation shows that economic benefit can be increased by up to 107.35% compared to TL on-off control. It is concluded that DLC is a feasible supplemental light control method, especially under low natural light conditions.

Time spent in physical activity and sedentary behaviors on the working day: the American time use survey.

PubMed

Tudor-Locke, Catrine; Leonardi, Claudia; Johnson, William D; Katzmarzyk, Peter T

2011-12-01

To determine time spent on the working day in sleep, work, sedentary behaviors, and light-, moderate-, and vigorous-intensity behaviors by occupation intensity. Data came from 30,758 working respondents to the 2003 to 2009 American Time Use Survey. Mean ± SEM time spent in work, sedentary behaviors, light-, moderate-, and vigorous-intensity activities, and sleep were computed by occupations classified as sedentary, light, moderate, and vigorous intensity. On average, approximately 32% of the 24-hour day was spent sleeping and approximately 31% was spent at work. Time spent in sedentary behaviors outside of work was higher, and light-intensity time was lower, with higher levels of intensity-defined occupation. Those employed in sedentary occupations were sedentary for approximately 11 hours per day, leaving little time to achieve recommended levels of physical activity for overall health.

Morning bright light exposure has no influence on self-chosen exercise intensity and mood in overweight individuals - A randomized controlled trial.

PubMed

Knaier, Raphael; Klenk, Christopher; Königstein, Karsten; Hinrichs, Timo; Rossmeissl, Anja; Infanger, Denis; Cajochen, Christian; Schmidt-Trucksäss, Arno

2018-04-01

Overweight is a worldwide increasing public health issue. Physical exercise is a useful countermeasure. Overweight individuals choose rather low exercise intensities, but especially high exercise intensities lead to higher energy expenditure and show beneficial health effects compared to lower exercise intensities. However, especially in the morning higher exercise intensities are likely to be avoided due to higher subjective effort. Bright light exposure has shown to increase maximum performance. The aim of this study was to investigate if bright light exposure can also increase self-chosen exercise intensity. We hypothesized that morning bright light exposure increases self-chosen exercise intensity of subsequent exercise through increased mood and reduced sleepiness in overweight individuals. In this randomized controlled single-blind parallel group design, 26 overweight individuals (11 males, 15 females; age 25 ± 5.7 years; body mass index 28.9 ± 2.1 kg/m 2 ) underwent three measurement appointments. On the first appointment, subjects performed a cardiopulmonary exercise test to measure maximum oxygen uptake (VO2max). Two days later a 30-min exercise session with self-chosen exercise intensity was performed for familiarization. Then subjects were randomly allocated to bright light (~4400 lx) or a control light (~230 lx) condition. Three to seven days later, subjects were exposed to light for 30 min starting at 8:00 am, immediately followed by a 30-min exercise session with persisting light exposure. Multidimensional mood questionnaires were filled out before and after the light exposure and after the exercise session. The primary outcome was the mean power output during the exercise session and the secondary outcome the rating on the three domains (i.e. good-bad; awake-tired; calm-nervous) of the multidimensional mood questionnaire. Mean power output during the exercise session was 92 ± 19 W in bright light and 80 ± 37 W in control light, respectively. In the multivariate analysis adjusted for VO2max, the mean power output during the exercise session was 8.5 W higher (95% confidence interval -12.7, 29.7; p = 0.416) for participants in bright light compared to control light. There were no significant differences between the groups for any of the three domains of the questionnaire at any time point. This is in contrast to longer lasting intervention studies that show positive influences on mood and suggests that bright light therapy requires repetitive sessions to improve mood in overweight individuals. In conclusion bright light exposure does not acutely increase self-chosen exercise intensity or improve mood in a 30-min exercise session starting at 08:30. However, regarding the fact that overweight is a worldwide and rapidly increasing public health issue even small increases in exercise intensity may be relevant. The trend toward superiority of bright light over control light implicates that further studies may be conducted in a larger scale. VO2max: maximum oxygen uptake; 95% CI: 95% confidence interval; SD: standard deviation.

Minimum emittance in TBA and MBA lattices

NASA Astrophysics Data System (ADS)

Xu, Gang; Peng, Yue-Mei

2015-03-01

For reaching a small emittance in a modern light source, triple bend achromats (TBA), theoretical minimum emittance (TME) and even multiple bend achromats (MBA) have been considered. This paper derived the necessary condition for achieving minimum emittance in TBA and MBA theoretically, where the bending angle of inner dipoles has a factor of 31/3 bigger than that of the outer dipoles. Here, we also calculated the conditions attaining the minimum emittance of TBA related to phase advance in some special cases with a pure mathematics method. These results may give some directions on lattice design.

Light shield and cooling apparatus. [high intensity ultraviolet lamp

NASA Technical Reports Server (NTRS)

Meador, T. G., Jr. (Inventor)

1974-01-01

A light shield and cooling apparatus was developed for a high intensity ultraviolet lamp including water and high pressure air for cooling and additional apparatus for shielding the light and suppressing the high pressure air noise.

Damaging effects of visible light. Comprehensive progress report

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1981-01-01

Research progress is reported on studies of retinal light damage. A myriad of variables effect the production of light damage. These include age, prior light history, body temperature, vitamin A status, intensity, wavelength and duration of light. The intensity-duration function and the age function have been studied in detail in rats. Studies have been begun on the wavelength variable. (ACR)

The twilight zone: ambient light levels trigger activity in primitive ants.

PubMed

Narendra, Ajay; Reid, Samuel F; Hemmi, Jan M

2010-05-22

Many animals become active during twilight, a narrow time window where the properties of the visual environment are dramatically different from both day and night. Despite the fact that many animals including mammals, reptiles, birds and insects become active in this specific temporal niche, we do not know what cues trigger this activity. To identify the onset of specific temporal niches, animals could anticipate the timing of regular events or directly measure environmental variables. We show that the Australian bull ant, Myrmecia pyriformis, starts foraging only during evening twilight throughout the year. The onset occurs neither at a specific temperature nor at a specific time relative to sunset, but at a specific ambient light intensity. Foraging onset occurs later when light intensities at sunset are brighter than normal or earlier when light intensities at sunset are darker than normal. By modifying ambient light intensity experimentally, we provide clear evidence that ants indeed measure light levels and do not rely on an internal rhythm to begin foraging. We suggest that the reason for restricting the foraging onset to twilight and measuring light intensity to trigger activity is to optimize the trade-off between predation risk and ease of navigation.

The twilight zone: ambient light levels trigger activity in primitive ants

PubMed Central

Narendra, Ajay; Reid, Samuel F.; Hemmi, Jan M.

2010-01-01

Many animals become active during twilight, a narrow time window where the properties of the visual environment are dramatically different from both day and night. Despite the fact that many animals including mammals, reptiles, birds and insects become active in this specific temporal niche, we do not know what cues trigger this activity. To identify the onset of specific temporal niches, animals could anticipate the timing of regular events or directly measure environmental variables. We show that the Australian bull ant, Myrmecia pyriformis, starts foraging only during evening twilight throughout the year. The onset occurs neither at a specific temperature nor at a specific time relative to sunset, but at a specific ambient light intensity. Foraging onset occurs later when light intensities at sunset are brighter than normal or earlier when light intensities at sunset are darker than normal. By modifying ambient light intensity experimentally, we provide clear evidence that ants indeed measure light levels and do not rely on an internal rhythm to begin foraging. We suggest that the reason for restricting the foraging onset to twilight and measuring light intensity to trigger activity is to optimize the trade-off between predation risk and ease of navigation. PMID:20129978

Clades of Photosynthetic Bacteria Belonging to the Genus Rhodopseudomonas Show Marked Diversity in Light-Harvesting Antenna Complex Gene Composition and Expression

DOE PAGES

Fixen, Kathryn R.; Oda, Yasuhiro; Harwood, Caroline S.; ...

2015-12-22

Many photosynthetic bacteria have peripheral light-harvesting (LH) antenna complexes that increase the efficiency of light energy capture. The purple nonsulfur photosynthetic bacteriumRhodopseudomonas palustrisproduces different types of LH complexes under high light intensities (LH2 complex) and low light intensities (LH3 and LH4 complexes). There are multiplepucBAoperons that encode the α and β peptides that make up these complexes. But, low-resolution structures, amino acid similarities between the complexes, and a lack of transcription analysis have made it difficult to determine the contributions of differentpucBAoperons to the composition and function of different LH complexes. It was also unclear how much diversity of LHmore » complexes exists inR. palustrisand affiliated strains. To address this, we undertook an integrative genomics approach using 20 sequenced strains. Gene content analysis revealed that even closely related strains have differences in theirpucBAgene content. Transcriptome analyses of the strains grown under high light and low light revealed that the patterns of expression of thepucBAoperons varied among strains grown under the same conditions. We also found that one set of LH2 complex proteins compensated for the lack of an LH4 complex under low light intensities but not under extremely low light intensities, indicating that there is functional redundancy between some of the LH complexes under certain light intensities. The variation observed in LH gene composition and expression inRhodopseudomonasstrains likely reflects how they have evolved to adapt to light conditions in specific soil and water microenvironments. ImportanceRhodopseudomonas palustrisis a phototrophic purple nonsulfur bacterium that adapts its photosystem to allow growth at a range of light intensities. It does this by adjusting the amount and composition of peripheral light-harvesting (LH) antenna complexes that it synthesizes.Rhodopseudomonasstrains are notable for containing numerous sets of light-harvesting genes. We determined the diversity of LH complexes and their transcript levels during growth under high and low light intensities in 20 sequenced genomes of strains related to the speciesRhodopseudomonas palustris. Finally, the data obtained are a resource for investigators with interests as wide-ranging as the biophysics of photosynthesis, the ecology of phototrophic bacteria, and the use of photosynthetic bacteria for biotechnology applications.« less

Clades of Photosynthetic Bacteria Belonging to the Genus Rhodopseudomonas Show Marked Diversity in Light-Harvesting Antenna Complex Gene Composition and Expression

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fixen, Kathryn R.; Oda, Yasuhiro; Harwood, Caroline S.

Many photosynthetic bacteria have peripheral light-harvesting (LH) antenna complexes that increase the efficiency of light energy capture. The purple nonsulfur photosynthetic bacteriumRhodopseudomonas palustrisproduces different types of LH complexes under high light intensities (LH2 complex) and low light intensities (LH3 and LH4 complexes). There are multiplepucBAoperons that encode the α and β peptides that make up these complexes. But, low-resolution structures, amino acid similarities between the complexes, and a lack of transcription analysis have made it difficult to determine the contributions of differentpucBAoperons to the composition and function of different LH complexes. It was also unclear how much diversity of LHmore » complexes exists inR. palustrisand affiliated strains. To address this, we undertook an integrative genomics approach using 20 sequenced strains. Gene content analysis revealed that even closely related strains have differences in theirpucBAgene content. Transcriptome analyses of the strains grown under high light and low light revealed that the patterns of expression of thepucBAoperons varied among strains grown under the same conditions. We also found that one set of LH2 complex proteins compensated for the lack of an LH4 complex under low light intensities but not under extremely low light intensities, indicating that there is functional redundancy between some of the LH complexes under certain light intensities. The variation observed in LH gene composition and expression inRhodopseudomonasstrains likely reflects how they have evolved to adapt to light conditions in specific soil and water microenvironments. ImportanceRhodopseudomonas palustrisis a phototrophic purple nonsulfur bacterium that adapts its photosystem to allow growth at a range of light intensities. It does this by adjusting the amount and composition of peripheral light-harvesting (LH) antenna complexes that it synthesizes.Rhodopseudomonasstrains are notable for containing numerous sets of light-harvesting genes. We determined the diversity of LH complexes and their transcript levels during growth under high and low light intensities in 20 sequenced genomes of strains related to the speciesRhodopseudomonas palustris. Finally, the data obtained are a resource for investigators with interests as wide-ranging as the biophysics of photosynthesis, the ecology of phototrophic bacteria, and the use of photosynthetic bacteria for biotechnology applications.« less

Using digital inpainting to estimate incident light intensity for the calculation of red blood cell oxygen saturation from microscopy images.

PubMed

Sové, Richard J; Drakos, Nicole E; Fraser, Graham M; Ellis, Christopher G

2018-05-25

Red blood cell oxygen saturation is an important indicator of oxygen supply to tissues in the body. Oxygen saturation can be measured by taking advantage of spectroscopic properties of hemoglobin. When this technique is applied to transmission microscopy, the calculation of saturation requires determination of incident light intensity at each pixel occupied by the red blood cell; this value is often approximated from a sequence of images as the maximum intensity over time. This method often fails when the red blood cells are moving too slowly, or if hematocrit is too large since there is not a large enough gap between the cells to accurately calculate the incident intensity value. A new method of approximating incident light intensity is proposed using digital inpainting. This novel approach estimates incident light intensity with an average percent error of approximately 3%, which exceeds the accuracy of the maximum intensity based method in most cases. The error in incident light intensity corresponds to a maximum error of approximately 2% saturation. Therefore, though this new method is computationally more demanding than the traditional technique, it can be used in cases where the maximum intensity-based method fails (e.g. stationary cells), or when higher accuracy is required. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Synchronous Crepuscular Flight of Female Asian Gypsy Moths: Relationships of Light Intensity and Ambient and Body Temperatures

Treesearch

Ralph E. Charlton; Ring T. Carde; William E. Wallner; William E. Wallner

1999-01-01

Female gypsy moths (Lymantria dispar) of Asian heritage studied in central Siberia and Germany exhibit a highly synchronous flight at dusk, after light intensity falls to about 2 lux. This critical light intensity sets the timing of flight behaviors independent of ambient temperature. Flight follows several minutes of preflight wing fanning during which females in...

Correlation between light levels and the development of deprivation myopia.

PubMed

Karouta, Cindy; Ashby, Regan Scott

2014-12-09

In chicks, daily exposure to bright light (15,000 lux) retards the development of form-deprivation myopia (FDM) by roughly 60%. This study investigated whether higher light intensities increase the amount of protection against FDM, and whether protection and light intensity are correlated. Furthermore, we examined if exposure to bright light can prevent the progression of FDM or whether it affects only the onset of experimental myopia. Experiment 1: Chicks wore translucent diffusers monocularly for a period of 7 days, with exposure to one of five light intensities (500, 10,000, 20,000, 30,000, and 40,000 lux, n = 12 per group). Experiment 2: Chickens wore translucent diffusers monocularly for 11 days and were split into three groups: (1) chicks reared under 500 lux, (2) chicks reared under 40,000 lux, and (3) chicks reared under 500 lux for the first 4 days and 40,000 lux for the remaining 7 days. A significant correlation was observed between log light intensity and the development of FDM, with a lesser myopic refraction (F (28, 330) = 60.86, P < 0.0001) and shorter axial length (F (4, 20) = 8.87, P < 0.0001) seen with increasing light intensities. The progression of FDM was halted in chicks that were switched from 500 to 40,000 lux. The level of protection from the development of FDM increases with increasing light intensity. Daily exposure to 40,000 lux almost completely prevents the onset of FDM and, once myopia is established, halts further progression. Copyright 2015 The Association for Research in Vision and Ophthalmology, Inc.

Measurement-device-independent quantum key distribution with correlated source-light-intensity errors

NASA Astrophysics Data System (ADS)

Jiang, Cong; Yu, Zong-Wen; Wang, Xiang-Bin

2018-04-01

We present an analysis for measurement-device-independent quantum key distribution with correlated source-light-intensity errors. Numerical results show that the results here can greatly improve the key rate especially with large intensity fluctuations and channel attenuation compared with prior results if the intensity fluctuations of different sources are correlated.

Biocapture of CO2 by Different Microalgal-Based Technologies for Biogas Upgrading and Simultaneous Biogas Slurry Purification under Various Light Intensities and Photoperiods

PubMed Central

Guo, Pengfei; Zhang, Yuejin; Zhao, Yongjun

2018-01-01

Co-cultivation of microalgae and microbes for pollutant removal from sewage is considered as an effective wastewater treatment method. The aim of this study is to screen the optimal photoperiod, light intensity and microalgae co-cultivation method for simultaneously removing nutrients in biogas slurry and capturing CO2 in biogas. The microalgae–fungi pellets are deemed to be a viable option because of their high specific growth rate and nutrient and CO2 removal efficiency under the photoperiod of 14 h light:10 h dark. The order of both the biogas slurry purification and biogas upgrading is ranked the same, that is Chlorella vulgaris–Ganoderma lucidum > Chlorella vulgaris–activated sludge > Chlorella vulgaris under different light intensities. For all cultivation methods, the moderate light intensity of 450 μmol m−2 s−1 is regarded as the best choice. This research revealed that the control of photoperiod and light intensity can promote the biological treatment process of biogas slurry purification and biogas upgrading using microalgal-based technology. PMID:29543784

Light intensity as major factor to maximize biomass and lipid productivity of Ettlia sp. in CO2-controlled photoautotrophic chemostat.

PubMed

Seo, Seong-Hyun; Ha, Ji-San; Yoo, Chan; Srivastava, Ankita; Ahn, Chi-Yong; Cho, Dae-Hyun; La, Hyun-Joon; Han, Myung-Soo; Oh, Hee-Mock

2017-11-01

The optimal culture conditions are critical factors for high microalgal biomass and lipid productivity. To optimize the photoautotrophic culture conditions, combination of the pH (regulated by CO 2 supply), dilution rate, and light intensity was systematically investigated for Ettlia sp. YC001 cultivation in a chemostat during 143days. The biomass productivity increased with the increase in dilution rate and light intensity, but decreased with increasing pH. The average lipid content was 19.8% and statistically non-variable among the tested conditions. The highest biomass and lipid productivities were 1.48gL -1 d -1 and 291.4mgL -1 d -1 with a pH of 6.5, dilution rate of 0.78d -1 , and light intensity of 1500μmolphotonsm -2 s -1 . With a sufficient supply of CO 2 and nutrients, the light intensity was the main determinant of the photosynthetic rate. Therefore, the surface-to-volume ratio of a photobioreactor should enable efficient light distribution to enhance microalgal growth. Copyright © 2017 Elsevier Ltd. All rights reserved.

LED power efficiency of biomass, fatty acid, and carotenoid production in Nannochloropsis microalgae.

PubMed

Ma, Ruijuan; Thomas-Hall, Skye R; Chua, Elvis T; Eltanahy, Eladl; Netzel, Michael E; Netzel, Gabriele; Lu, Yinghua; Schenk, Peer M

2018-03-01

The microalga Nannochloropsis produces high-value omega-3-rich fatty acids and carotenoids. In this study the effects of light intensity and wavelength on biomass, fatty acid, and carotenoid production with respect to light output efficiency were investigated. Similar biomass and fatty acid yields were obtained at high light intensity (150 μmol m -2  s -1 ) LEDs on day 7 and low light intensity (50 μmol m -2  s -1 ) LEDs on day 11 during cultivation, but the power efficiencies of biomass and fatty acid (specifically eicosapentaenoic acid) production were higher for low light intensity. Interestingly, low light intensity enhanced both, carotenoid power efficiency of carotenoid biosynthesis and yield. White LEDs were neither advantageous for biomass and fatty acid yields, nor the power efficiency of biomass, fatty acid, and carotenoid production. Noticeably, red LED resulted in the highest biomass and fatty acid power efficiency, suggesting that LEDs can be fine-tuned to grow Nannochloropsis algae more energy-efficiently. Copyright © 2017 Elsevier Ltd. All rights reserved.

Transfer cell wall ingrowths and vein loading characteristics in pea leaf discs. [Pisum sativum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wimmers, L.E.; Turgeon, R.

1987-04-01

Transfer cell wall ingrowths are thought to increase transport capacity by increasing plasmalemma surface area. Leaf minor vein phloem transfer cells presumably enhance phloem loading. In Pisum sativum cv. Little marvel grown under different light regimes (150 to 1000 ..mu..mol photons m/sup -2/ sec/sup -1/) there is a positive correlation between light intensity and wall ingrowth area in phloem transfer cells. The extent of ingrowth and correlation to light intensity is greatest in minor veins, decreasing as vein size increases. Vein loading was assayed by floating abraded leaf discs on /sup 14/C-sucrose (10 mM). There is a positive correlation betweenmore » uptake and transfer cell wall area, although the latter increased more than the former. The difference in uptake is stable throughout the photoperiod, and is also stable in mature leaves for at least four days after plants are transfered to a different light intensity. Sucrose uptake is biphasic. The saturable component of uptake is sensitive to light intensity, the Km for sucrose is negatively correlated to light intensity, while V/sub max/remains unchanged.« less

Biocapture of CO₂ by Different Microalgal-Based Technologies for Biogas Upgrading and Simultaneous Biogas Slurry Purification under Various Light Intensities and Photoperiods.

PubMed

Guo, Pengfei; Zhang, Yuejin; Zhao, Yongjun

2018-03-15

Abstract : Co-cultivation of microalgae and microbes for pollutant removal from sewage is considered as an effective wastewater treatment method. The aim of this study is to screen the optimal photoperiod, light intensity and microalgae co-cultivation method for simultaneously removing nutrients in biogas slurry and capturing CO₂ in biogas. The microalgae-fungi pellets are deemed to be a viable option because of their high specific growth rate and nutrient and CO 2 removal efficiency under the photoperiod of 14 h light:10 h dark. The order of both the biogas slurry purification and biogas upgrading is ranked the same, that is Chlorella vulga ris - Ganoderma lucidum > Chlorella vulga ris -activated sludge > Chlorella vulgaris under different light intensities. For all cultivation methods, the moderate light intensity of 450 μmol m -2 s -1 is regarded as the best choice. This research revealed that the control of photoperiod and light intensity can promote the biological treatment process of biogas slurry purification and biogas upgrading using microalgal-based technology.

Auxin-to-Gibberellin Ratio as a Signal for Light Intensity and Quality in Regulating Soybean Growth and Matter Partitioning

PubMed Central

Yang, Feng; Fan, Yuanfang; Wu, Xiaoling; Cheng, Yajiao; Liu, Qinlin; Feng, Lingyang; Chen, Junxu; Wang, Zhonglin; Wang, Xiaochun; Yong, Taiwen; Liu, Weiguo; Liu, Jiang; Du, Junbo; Shu, Kai; Yang, Wenyu

2018-01-01

The intensity and quality (red to far-red (R/Fr) ratio) of light directly affect growth of plant under shading. Gibberellins (GAs) and auxin [indole-3-acetic acid (IAA)] play important roles in mediating the shading adaptive responses of plants. Thus, the intensity and quality of the uncoupling light from shading were assessed to identify the influence of each component on the morphology and matter distribution of the leaf, stem, and petiole. This assessment was based on the changes in endogenous Gibberellin 1 (GA1) and IAA levels. Soybean plants were grown in a growth chamber with four treatments [normal (N), N+Fr, low (L), and L+Fr light]. Results revealed that the reductions in photosynthetically active radiation (PAR) and R/Fr ratio equally increased height and stem mass fractions (SMFs) of the soybean seedling. The light intensity significantly influenced the dry mass per unit area and mass fraction of soybean leaves, whereas the light quality regulated the petiole elongation and mass fraction. Low R/Fr ratio (high Fr light) increased the soybean biomass by improving the photosynthetic assimilation rate and quantum yield of photosystem II. In addition, the IAA and GA1 levels in the leaf, stem, and petiole did not reflect the growth response trends of each tissue toward light intensity and quality; however, trends of the IAA-to-GA1 content ratios were similar to those of the growth and matter allocation of each soybean tissue under different light environments. Therefore, the response of growth and matter allocation of soybean to light intensity and quality may be regulated by the IAA-to-GA1 content ratio in the tissues of the soybean plant. PMID:29441084

Evaluation of shear bond strength of orthodontic brackets using trans-illumination technique with different curing profiles of LED light-curing unit in posterior teeth.

PubMed

Heravi, Farzin; Moazzami, Saied Mostafa; Ghaffari, Negin; Jalayer, Javad; Bozorgnia, Yasaman

2013-11-21

Although using light-cured composites for bonding orthodontic brackets has become increasingly popular, curing light cannot penetrate the metallic bulk of brackets and polymerization of composites is limited to the edges. Limited access and poor direct sight may be a problem in the posterior teeth. Meanwhile, effectiveness of the trans-illumination technique is questionable due to increased bucco-lingual thickness of the posterior teeth. Light-emitting diode (LED) light-curing units cause less temperature rise and lower risk to the pulpal tissue. The purpose of this study was to evaluate the clinical effectiveness of trans-illumination technique in bonding metallic brackets to premolars, using different light intensities and curing times of an LED light-curing unit. Sixty premolars were randomly divided into six groups. Bonding of brackets was done with 40- and 80-s light curing from the buccal or lingual aspect with different intensities. Shear bond strengths of brackets were measured using a universal testing machine. Data were analyzed by one-way analysis of variance test and Duncan's post hoc test. The highest shear bond belonged to group 2 (high intensity, 40 s, buccal) and the lowest belonged to group 3 (low intensity, 40 s, lingual). Bond strength means in control groups were significantly higher than those in experimental groups. In all experimental groups except group 6 (80 s, high intensity, lingual), shear bond strength was below the clinically accepted values. In clinical limitations where light curing from the same side of the bracket is not possible, doubling the curing time and increasing the light intensity during trans-illumination are recommended for achieving acceptable bond strengths.

Attenuating Photostress and Glare Disability in Pseudophakic Patients through the Addition of a Short-Wave Absorbing Filter.

PubMed

Hammond, Billy R

2015-01-01

To evaluate the effects of filtering short wavelength light on visual performance under intense light conditions among pseudophakic patients previously implanted with a clear intraocular lens (IOL). This was a patient-masked, randomized crossover study conducted at 6 clinical sites in the United States between September 2013 and January 2014. One hundred fifty-four bilaterally pseudophakic patients were recruited. Photostress recovery time and glare disability thresholds were measured with clip-on blue-light-filtering and placebo (clear; no blue-light filtration) glasses worn over patients' habitual correction. Photostress recovery time was quantified as the time necessary to regain sight of a grating target after intense light exposure. Glare disability threshold was assessed as the intensity of a white-light annulus necessary to obscure a central target. The order of filter used and test eye were randomized across patients. Photostress recovery time and glare disability thresholds were significantly improved (both P < 0.0001) when patients used blue-light-filtering glasses compared with clear, nonfiltering glasses. Compared with a nonfiltering placebo, adding a clip-on blue-absorbing filter to the glasses of pseudophakic patients implanted with clear IOLs significantly increased their ability to cope with glare and to recover normal viewing after an intensive photostress. This result implies that IOL designs with blue-light-filtering characteristics may be beneficial under intense light conditions.

Remarkable modification of light curves for shadowing effects on irregular surfaces - The case of the asteroid 37 Fides

NASA Technical Reports Server (NTRS)

Zappala, V.; Di Martino, M.; Scaltriti, F.; Burchi, R.; Milano, L.; Young, J. W.; Wahlgren, G.; Pavlovski, K.

1983-01-01

Photometric observations of the asteroid 37 Fides carried out at four observatories are reported. The data were taken at phase angles ranging from approximately 2-23 deg. A composite of the light curves obtained revealed that, considering a period of 7.33 hr, the full cycle light curve exhibits one maximum and one minimum. An increase in brightness was observed following a primary minimum, a factor that indicated the cyclical appearance and disappearance of a large topographical feature. It is concluded that the 7.33 hr period is the rotational speed of the asteroid, in contrast with a previously held 14.66 hr rotational period. The method is concluded useful for identifying rotational periods of asteroids when only partial light curve data from different sources is available, and when the projections can be checked observationally.

46 CFR 169.549 - Ring lifebuoys and water lights.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 7 2011-10-01 2011-10-01 false Ring lifebuoys and water lights. 169.549 Section 169.549 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Lifesaving and Firefighting Equipment Additional Lifesaving Equipment § 169.549 Ring lifebuoys and water lights. (a)(1) The minimum number of...

46 CFR 169.549 - Ring lifebuoys and water lights.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Ring lifebuoys and water lights. 169.549 Section 169.549 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Lifesaving and Firefighting Equipment Additional Lifesaving Equipment § 169.549 Ring lifebuoys and water lights. (a)(1) The minimum number of...

46 CFR 169.549 - Ring lifebuoys and water lights.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 7 2013-10-01 2013-10-01 false Ring lifebuoys and water lights. 169.549 Section 169.549 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Lifesaving and Firefighting Equipment Additional Lifesaving Equipment § 169.549 Ring lifebuoys and water lights. (a)(1) The minimum number of...

A Screening Model to Predict Microalgae Biomass Growth in Photobioreactors and Raceway Ponds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huesemann, Michael H.; Van Wagenen, Jonathan M.; Miller, Tyler W.

A microalgae biomass growth model was developed for screening novel strains for their potential to exhibit high biomass productivities under nutrient-replete conditions in photobioreactors or outdoor ponds. Growth is modeled by first estimating the light attenuation by biomass according to Beer-Lambert’s law, and then calculating the specific growth rate in discretized culture volume slices that receive declining light intensities due to attenuation. The model requires only two physical and two species-specific biological input parameters, all of which are relatively easy to determine: incident light intensity, culture depth, as well as the biomass light absorption coefficient and the specific growth ratemore » as a function of light intensity. Roux bottle culture experiments were performed with Nannochloropsis salina at constant temperature (23 °C) at six different incident light intensities (5, 10, 25, 50, 100, 250, and 850 μmol/m2∙ sec) to determine both the specific growth rate under non-shading conditions and the biomass light absorption coefficient as a function of light intensity. The model was successful in predicting the biomass growth rate in these Roux bottle cultures during the light-limited linear phase at different incident light intensities. Model predictions were moderately sensitive to minor variations in the values of input parameters. The model was also successful in predicting the growth performance of Chlorella sp. cultured in LED-lighted 800 L raceway ponds operated at constant temperature (30 °C) and constant light intensity (1650 μmol/m2∙ sec). Measurements of oxygen concentrations as a function of time demonstrated that following exposure to darkness, it takes at least 5 seconds for cells to initiate dark respiration. As a result, biomass loss due to dark respiration in the aphotic zone of a culture is unlikely to occur in highly mixed small-scale photobioreactors where cells move rapidly in and out of the light. By contrast, as supported also by the growth model, biomass loss due to dark respiration occurs in the dark zones of the relatively less well mixed pond cultures. In addition to screening novel microalgae strains for high biomass productivities, the model can also be used for optimizing the pond design and operation. Additional research is needed to validate the biomass growth model for other microalgae species and for the more realistic case of fluctuating temperatures and light intensities observed in outdoor pond cultures.« less

A screening model to predict microalgae biomass growth in photobioreactors and raceway ponds.

PubMed

Huesemann, M H; Van Wagenen, J; Miller, T; Chavis, A; Hobbs, S; Crowe, B

2013-06-01

A microalgae biomass growth model was developed for screening novel strains for their potential to exhibit high biomass productivities under nutrient-replete conditions in photobioreactors or outdoor ponds. Growth is modeled by first estimating the light attenuation by biomass according to Beer-Lambert's Law, and then calculating the specific growth rate in discretized culture volume slices that receive declining light intensities due to attenuation. The model uses only two physical and two species-specific biological input parameters, all of which are relatively easy to determine: incident light intensity, culture depth, as well as the biomass light absorption coefficient and the specific growth rate as a function of light intensity. Roux bottle culture experiments were performed with Nannochloropsis salina at constant temperature (23°C) at six different incident light intensities (10, 25, 50, 100, 250, and 850 µmol/m(2)  s) to determine both the specific growth rate under non-shading conditions and the biomass light absorption coefficient as a function of light intensity. The model was successful in predicting the biomass growth rate in these Roux bottle batch cultures during the light-limited linear phase at different incident light intensities. Model predictions were moderately sensitive to minor variations in the values of input parameters. The model was also successful in predicting the growth performance of Chlorella sp. cultured in LED-lighted 800 L raceway ponds operated in batch mode at constant temperature (30°C) and constant light intensity (1,650 µmol/m(2)  s). Measurements of oxygen concentrations as a function of time demonstrated that following exposure to darkness, it takes at least 5 s for cells to initiate dark respiration. As a result, biomass loss due to dark respiration in the aphotic zone of a culture is unlikely to occur in highly mixed small-scale photobioreactors where cells move rapidly in and out of the light. By contrast, as supported also by the growth model, biomass loss due to dark respiration occurs in the dark zones of the relatively less well-mixed pond cultures. In addition to screening novel microalgae strains for high biomass productivities, the model can also be used for optimizing the pond design and operation. Additional research is needed to validate the biomass growth model for other microalgae species and for the more realistic case of fluctuating temperatures and light intensities observed in outdoor pond cultures. Copyright © 2012 Wiley Periodicals, Inc.

Leaf non-structural carbohydrate allocation and C:N:P stoichiometry in response to light acclimation in seedlings of two subtropical shade-tolerant tree species.

PubMed

Xie, Hongtao; Yu, Mukui; Cheng, Xiangrong

2018-03-01

Light availability greatly affects plant growth and development. In shaded environments, plants must respond to reduced light intensity to ensure a regular rate of photosynthesis to maintain the dynamic balance of nutrients, such as leaf non-structural carbohydrates (NSCs), carbon (C), nitrogen (N) and phosphorus (P). To improve our understanding of the nutrient utilization strategies of understory shade-tolerant plants, we compared the variations in leaf NSCs, C, N and P in response to heterogeneous controlled light conditions between two subtropical evergreen broadleaf shade-tolerant species, Elaeocarpus sylvestris (E. sylvestris) and Illicium henryi (I. henryi). Light intensity treatments were applied at five levels (100%, 52%, 33%, 15% and 6% full sunlight) for 30 weeks to identify the effects of reduced light intensity on leaf NSC allocation patterns and leaf C:N:P stoichiometry characteristics. We found that leaf soluble sugar, starch and NSC concentrations in E. sylvestris showed decreasing trends with reduced light intensity, whereas I. henryi presented slightly increasing trends from 100% to 15% full sunlight and then significant decreases at extremely low light intensity (6% full sunlight). The soluble sugar/starch ratio of E. sylvestris decreased with decreasing light intensity, whereas that of I. henryi remained stable. Moreover, both species exhibited increasing trends in leaf N and P concentrations but limited leaf N:P and C:P ratio fluctuations with decreasing light intensity, revealing their adaptive strategies for poor light environments and their growth strategies under ideal light environments. There were highly significant correlations between leaf NSC variables and C:N:P stoichiometric variables in both species, revealing a trade-off in photosynthesis production between leaf NSC and carbon allocation. Thus, shade-tolerant plants readjusted their allocation of leaf NSCs, C, N and P in response to light acclimation. Redundancy analysis showed that leaf morphological features of both E. sylvestris and I. henryi affected their corresponding leaf nutrient traits. These results improve our understanding of the dynamic balance between leaf NSCs and leaf C, N and P components in the nutritional metabolism of shade-tolerant plants. Two species of understory shade-tolerant plants responded differently to varying light intensities in terms of leaf non-structural carbohydrate allocation and the utilization of carbon, nitrogen and phosphorus to balance nutritional metabolism and adapt to environmental stress. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Evaluating physical and perceptual responses to exergames in Chinese children.

PubMed

Lau, Patrick W C; Liang, Yan; Lau, Erica Y; Choi, Choung-Rak; Kim, Chang-Gyun; Shin, Myung-Soo

2015-04-13

The primary objective of this study was to examine whether exergames could help children reach the recommendations for PA and cardiorespiratory fitness regarding exercise intensity. Differences in perceived physical exertion, EE, VO2, and HR between normal weight (NW) and overweight (OW) children participating in exergames were also examined. Twenty-one children (age: 10.45 ± 0.88) were assessed for EE, VO2 and HR during rest, in a maximal treadmill test, and while playing different exergames. Ratings of perceived exertion (RPE) (category range: 0 to 10) were also measured during exergaming. Three types of exergames were examined: running, table tennis, and dancing. These games were either performed on a Chinese game console, I-Dong, or another well-developed Western game console (Sony PlayStation 3 or Nintendo Wii). Exergaming resulted in EE (kcal/min) from 2.05-5.14, VO2 (mL/kg/min) from 9.98-25.54, and HR (beats per minute) from 98.05-149.66. Children reported RPE ranging from 1.29 to 5.29. The Chinese exergame, I-Dong Running, was the only game in which children reached a moderate intensity and met the recommended minimum VO2reserve (50%) for cardiorespiratory fitness. Exergames could provide alternative opportunities to enhance children's physical activity. They could be used as light-to-moderate PA, and with exergames, children can even reach the recommended intensity for developing and maintaining cardiorespiratory fitness.

Effects of different light intensities in the morning on dim light melatonin onset.

PubMed

Kozaki, Tomoaki; Toda, Naohiro; Noguchi, Hiroki; Yasukouchi, Akira

2011-01-01

The present study evaluated the effects of exposure to light intensity in the morning on dim light melatonin onset (DLMO). The tested light intensities were 750 lux, 150 lux, 3000 lux, 6000 lux and 12,000 lux (horizontal illuminance at cornea), using commercial 5000 K fluorescent lamps. Eleven healthy males aged 21-31 participated in 2-day experiments for each light condition. On the first experimental day (day 1), subjects were exposed to dim light (<30 lux) for 3 h in the morning (09:00-12:00). On the same day, saliva samples were taken in dim light (<30 lux) every 30 min from 21:00 to 01:00 to determine the DLMO phase. The subjects were allowed to sleep from 01:00 to 08:00. On the second experimental day (day 2), the subjects were exposed to experimental light conditions for 3 h in the morning. The experimental schedule after light exposure was the same as on day 1. On comparing day 2 with day 1, significant phase advances of DLMO were obtained at 3000 lux, 6000 lux and 12,000 lux. These findings indicate that exposure to a necessary intensity from an ordinary light source, such as a fluorescent lamp, in the morning within one day affects melatonin secretion.

Effects of light quality on leaf morphogenesis of a heterophyllous amphibious plant, Rotala hippuris

PubMed Central

Momokawa, Naoko; Kadono, Yasuro; Kudoh, Hiroshi

2011-01-01

Background and Aims For heterophyllous amphibious plants that experience fluctuating water levels, it is critical to control leaf development precisely in response to environmental cues that can serve as a quantitative index of water depth. Light quality can serve as such a cue because the ratio of red light relative to far-red light (R/FR) increases and blue-light intensity decreases with increasing water depth. Growth experiments were conducted to examine how R/FR and blue-light intensity alter leaf morphology of a heterophyllous amphibious plant, Rotala hippuris. Methods Using combinations of far red (730 nm), red (660 nm) and blue (470 nm) light-emitting diodes (LEDs), growth experiments were used to quantitatively evaluate the effects of the R/FR ratio and blue-light intensity on leaf morphology. Key Results Under the natural light regime in an outside growth garden, R. hippuris produced distinct leaves under submerged and aerial conditions. R/FR and blue-light intensity were found to markedly affect heterophyllous leaf formation. Higher and lower R/FR caused leaf characters more typical of submerged and aerial leaves, respectively, in both aerial and submerged conditions, in accordance with natural distribution of leaf types and light under water. High blue light caused a shift of trait values toward those of typical aerial leaves, and the response was most prominent under conditions of R/FR that were expected near the water surface. Conclusions R/FR and blue-light intensity provides quantitative cues for R. hippuris to detect water depth and determine the developmental fates of leaves, especially near the water surface. The utilization of these quantitative cues is expected to be important in habitats where plants experience water-level fluctuation. PMID:21896573

Effects of light quality on leaf morphogenesis of a heterophyllous amphibious plant, Rotala hippuris.

PubMed

Momokawa, Naoko; Kadono, Yasuro; Kudoh, Hiroshi

2011-11-01

For heterophyllous amphibious plants that experience fluctuating water levels, it is critical to control leaf development precisely in response to environmental cues that can serve as a quantitative index of water depth. Light quality can serve as such a cue because the ratio of red light relative to far-red light (R/FR) increases and blue-light intensity decreases with increasing water depth. Growth experiments were conducted to examine how R/FR and blue-light intensity alter leaf morphology of a heterophyllous amphibious plant, Rotala hippuris. Using combinations of far red (730 nm), red (660 nm) and blue (470 nm) light-emitting diodes (LEDs), growth experiments were used to quantitatively evaluate the effects of the R/FR ratio and blue-light intensity on leaf morphology. Under the natural light regime in an outside growth garden, R. hippuris produced distinct leaves under submerged and aerial conditions. R/FR and blue-light intensity were found to markedly affect heterophyllous leaf formation. Higher and lower R/FR caused leaf characters more typical of submerged and aerial leaves, respectively, in both aerial and submerged conditions, in accordance with natural distribution of leaf types and light under water. High blue light caused a shift of trait values toward those of typical aerial leaves, and the response was most prominent under conditions of R/FR that were expected near the water surface. R/FR and blue-light intensity provides quantitative cues for R. hippuris to detect water depth and determine the developmental fates of leaves, especially near the water surface. The utilization of these quantitative cues is expected to be important in habitats where plants experience water-level fluctuation.

Correlated-Intensity velocimeter for Arbitrary Reflector

DOEpatents

Wang, Zhehui; Luo, Shengnian; Barnes, Cris W.; Paul, Stephen F.

2008-11-11

A velocimetry apparatus and method comprising splitting incoming reflected laser light and directing the laser light into first and second arms, filtering the laser light with passband filters in the first and second arms, one having a positive passband slope and the other having a negative passband slope, and detecting the filtered laser light via light intensity detectors following the passband filters in the first and second arms

Functional Diversity of Photosynthetic Light Use of 16 Vascular Epiphyte Species Under Fluctuating Irradiance in the Canopy of a Giant Virola michelii (Myristicaceae) Tree in the Tropical Lowland Forest of French Guyana

PubMed Central

Rascher, Uwe; Freiberg, Martin; Lüttge, Ulrich

2011-01-01

Here we present the first study, in which a large number of different vascular epiphyte species were measured for their photosynthetic performance in the natural environment of their phorophyte in the lowland rainforest of French Guyana. More than 70 epiphyte species covered the host tree in a dense cover. Of these, the photosynthesis of 16 abundant species was analyzed intensely over several months. Moreover, the light environment was characterized with newly developed light sensors that recorded continuously and with high temporal resolution light intensity next to the epiphytes. Light intensity was highly fluctuating and showed great site specific spatio-temporal variations of photosynthetic photon flux. Using a novel computer routine we quantified the integrated light intensity the epiphytes were exposed to in a 3 h window and we related this light intensity to measurements of the actual photosynthetic status. It could be shown that the photosynthetic apparatus of the epiphytes was well adapted to the quickly changing light conditions. Some of the epiphytes were chronically photoinhibited at predawn and significant acute photoinhibition, expressed by a reduction of potential quantum efficiency (Fv/Fm)30′, was observed during the day. By correlating (Fv/Fm)30′ to the integrated and weighted light intensity perceived during the previous 3 h, it became clear that acute photoinhibition was related to light environment prior to the measurements. Additionally photosynthetic performance was not determined by rain events, with the exception of an Aechmea species. This holds true for all the other 15 species of this study and we thus conclude that actual photosynthesis of these tropical epiphytes was determined by the specific and fluctuating light conditions of their microhabitat and cannot be simply attributed to light-adapted ancestors. PMID:22629271

Nonlinear light-matter interactions in engineered optical media

NASA Astrophysics Data System (ADS)

Litchinitser, Natalia

In this talk, we consider fundamental optical phenomena at the interface of nonlinear and singular optics in artificial media, including theoretical and experimental studies of linear and nonlinear light-matter interactions of vector and singular optical beams in metamaterials. We show that unique optical properties of metamaterials open unlimited prospects to ``engineer'' light itself. Thanks to their ability to manipulate both electric and magnetic field components, metamaterials open new degrees of freedom for tailoring complex polarization states and orbital angular momentum (OAM) of light. We will discuss several approaches to structured light manipulation on the nanoscale using metal-dielectric, all-dielectric and hyperbolic metamaterials. These new functionalities, including polarization and OAM conversion, beam magnification and de-magnification, and sub-wavelength imaging using novel non-resonant hyperlens are likely to enable a new generation of on-chip or all-fiber structured light applications. The emergence of metamaterials also has a strong potential to enable a plethora of novel nonlinear light-matter interactions and even new nonlinear materials. In particular, nonlinear focusing and defocusing effects are of paramount importance for manipulation of the minimum focusing spot size of structured light beams necessary for nanoscale trapping, manipulation, and fundamental spectroscopic studies. Colloidal suspensions offer as a promising platform for engineering polarizibilities and realization of large and tunable nonlinearities. We will present our recent studies of the phenomenon of spatial modulational instability leading to laser beam filamentation in an engineered soft-matter nonlinear medium. Finally, we introduce so-called virtual hyperbolic metamaterials formed by an array of plasma channels in air as a result of self-focusing of an intense laser pulse, and show that such structure can be used to manipulate microwave beams in a free space. This work was supported by the Army Research Office Awards (W911NF-15-1-0146, W911NF-11-1-0297).

Müller glial cells contribute to dim light vision in the spectacled caiman (Caiman crocodilus fuscus): Analysis of retinal light transmission.

PubMed

Agte, Silke; Savvinov, Alexey; Karl, Anett; Zayas-Santiago, Astrid; Ulbricht, Elke; Makarov, Vladimir I; Reichenbach, Andreas; Bringmann, Andreas; Skatchkov, Serguei N

2018-05-16

In this study, we show the capability of Müller glial cells to transport light through the inverted retina of reptiles, specifically the retina of the spectacled caimans. Thus, confirming that Müller cells of lower vertebrates also improve retinal light transmission. Confocal imaging of freshly isolated retinal wholemounts, that preserved the refractive index landscape of the tissue, indicated that the retina of the spectacled caiman is adapted for vision under dim light conditions. For light transmission experiments, we used a setup with two axially aligned objectives imaging the retina from both sides to project the light onto the inner (vitreal) surface and to detect the transmitted light behind the retina at the receptor layer. Simultaneously, a confocal microscope obtained images of the Müller cells embedded within the vital tissue. Projections of light onto several representative Müller cell trunks within the inner plexiform layer, i.e. (i) trunks with a straight orientation, (ii) trunks which are formed by the inner processes and (iii) trunks which get split into inner processes, were associated with increases in the intensity of the transmitted light. Projections of light onto the periphery of the Müller cell endfeet resulted in a lower intensity of transmitted light. In this way, retinal glial (Müller) cells support dim light vision by improving the signal-to-noise ratio which increases the sensitivity to light. The field of illuminated photoreceptors mainly include rods reflecting the rod dominance of the of tissue. A subpopulation of Müller cells with downstreaming cone cells led to a high-intensity illumination of the cones, while the surrounding rods were illuminated by light of lower intensity. Therefore, Müller cells that lie in front of cones may adapt the intensity of the transmitted light to the different sensitivities of cones and rods, presumably allowing a simultaneous vision with both receptor types under dim light conditions. Copyright © 2018 Elsevier Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alekseev, A E; Potapov, V T; Gorshkov, B G

We report the results of studying statistical properties of the intensity of partially polarised coherent light backscattered by a single mode optical fibre. An expression is derived for the deviation of the backscattered light intensity depending on the scattering region length, the degree of the light source coherence and the degree of scattered light polarisation. It is shown that the backscattered light in a fibre scattered-light interferometer is partially polarised with the polarisation degree P = 1/3 in the case of external perturbations of the interferometer fibre. (scattering of light)

Light Intensity Physical Activity Trial

ClinicalTrials.gov

2018-01-30

Diabetes Mellitus; Physical Exercise; Light Intensity Physical Activity; Arterial Stiffness; Aortic Stiffness; Pulse Wave Velocity; Type2 Diabetes; Sedentary Lifestyle; Artery Disease; Physical Activity

Method of absorbance correction in a spectroscopic heating value sensor

DOEpatents

Saveliev, Alexei; Jangale, Vilas Vyankatrao; Zelepouga, Sergeui; Pratapas, John

2013-09-17

A method and apparatus for absorbance correction in a spectroscopic heating value sensor in which a reference light intensity measurement is made on a non-absorbing reference fluid, a light intensity measurement is made on a sample fluid, and a measured light absorbance of the sample fluid is determined. A corrective light intensity measurement at a non-absorbing wavelength of the sample fluid is made on the sample fluid from which an absorbance correction factor is determined. The absorbance correction factor is then applied to the measured light absorbance of the sample fluid to arrive at a true or accurate absorbance for the sample fluid.

Fiber optic sensing system

NASA Technical Reports Server (NTRS)

Adamovsky, Grigory (Inventor)

1991-01-01

A fiber optic interferometer utilizes a low coherence light emitting diode (LED) laser as a light source which is filtered and driven at two RF frequencies, high and low, that are specific to the initial length of the resonator chamber. A displacement of a reflecting mirror changes the length traveled by the nonreferencing signal. The low frequency light undergoes destructive interference which reduces the average intensity of the wave while the high frequency light undergoes constructive interference which increases the average intensity of the wave. The ratio of these two intensity measurements is proportional to the displacement incurred.

78 FR 2868 - Draft Environmental Assessment for Rulemaking To Establish Minimum Sound Requirements for Hybrid...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-14

... require hybrid and electric passenger cars, light trucks, medium and heavy duty trucks and buses, low... Sound Requirements for Hybrid and Electric Vehicles AGENCY: National Highway Traffic Safety... minimum sound requirements for hybrid and electric vehicles. DATES: Comments must be received on or before...

Female Flight Propensity and Capability in Lymantria dispar (Lepidoptera: Lymantriidae) from Russia, North America, and Their Reciprocal F1 Hybrids

Treesearch

M.A. Keena

2001-01-01

In the laboratory, the timing of both preflight and flight behaviors of the Asian strain of female gypsy moths, Lymantria dispar L., was regulated primarily by light intensity. The shortest times to initiation of wing fanning and flight occurred at 0.1 lux, the lowest light intensity evaluated. A gradual decrease in light intensity, compared with an instantaneous...

Transcriptome analysis of the cyanobacterium Synechocystis sp. PCC 6803 and mechanisms of photoinhibition tolerance under extreme high light conditions.

PubMed

Ogawa, Kenichi; Yoshikawa, Katsunori; Matsuda, Fumio; Toya, Yoshihiro; Shimizu, Hiroshi

2018-06-12

Photoinhibition, or cell damage caused by excessively intense light is a major issue for the industrial use of cyanobacteria. To investigate the mechanism of responses to extreme high light intensity, gene expression analysis was performed using the model cyanobacterium Synechocystis sp. PCC 6803 (PCC 6803) cultured under various light intensities. The culture profile data demonstrated that, in contrast to the slow cell growth observed under low light intensities (30 and 50 μmol m -2  s -1 ), maximal cell growth was observed under mid light conditions (300 and 1000 μmol m -2  s -1 ). PCC 6803 cells exhibited photoinhibition when cultured under excessive high light intensities of 1100 and 1300 μmol m -2  s -1 . From the low to the mid light conditions, the expression of genes related to light harvesting systems was repressed, whereas that of CO 2 fixation and of D1 protein turnover-related genes was induced. Gene expression data also revealed that the down-regulation of genes related to flagellum synthesis (pilA2), pyridine nucleotide transhydrogenase (pntA and pntB), and sigma factor (sigA and sigF) represents the key responses of PCC 6803 under excessive high light conditions. The results obtained in this study provide further understanding of high light tolerance mechanisms and should help to improve the productivity of bioprocess using cyanobacteria. Copyright © 2018 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Physiological characteristics, dry matter, and active component accumulation patterns of Changium smyrnioides in response to a light intensity gradient.

PubMed

Wang, Chang-Lin; Guo, Qiao-Sheng; Zhu, Zai-Biao; Cheng, Bo-Xing

2017-12-01

Changium smyrnioides Wolff (Apiaceae) is an endangered medicinal plant with numerous pharmacological uses. To investigate the effect of light intensity levels on the growth and accumulation of secondary metabolites of C. smyrnioides, cultivated seedlings were subjected to different relative light intensities via sun-shading. Changium smyrnioides seedlings were subjected to five irradiance treatments (100, 60.54, 44.84, 31.39, and 10.56% sunlight) in glasshouse for 9 months. Enzymatic and non-enzymatic antioxidants with spectrophotometric method, photosynthetic parameters with Li-6400XT, dry matter accumulation and active component contents in the root with spectrophotometric and HPLC method were analyzed. With an increase in relative light intensity levels, activities of enzymatic and non-enzymatic antioxidants, and malondialdehyde (MDA) contents were increased overall, while net photosynthetic rate (P n ) and dry matter accumulation patter first increased and then declined. The highest net photosynthetic rate (30.68 μmol/m 2 ·s) and dry root weight (5.07 g) were achieved under 60.54% sunlight. Lower relative light intensity levels stimulated the accumulation levels of bioactive compounds in the roots so that the highest contents of mannitol (1.35%) and choline (405.58 μg/g) were recorded under 31.39% sunlight, and the highest polysaccharide content (10.80%) were achieved under 44.84% sunlight. With a decrease in the relative light intensity levels, the water-soluble component content increased first and then decreased. The results revealed that 31.39-60.54% sunlight serve as appropriate relative light intensity conditions for cultivated C. smyrnioides.

Estimation of effective day length at any light intensity using solar radiation data.

PubMed

Yokoya, Masana; Shimizu, Hideyasu

2011-11-01

The influence of day length on living creatures differs with the photosensitivity of the creature; however, the possible sunshine duration (N(0)) might be an inadequate index of the photoperiod for creatures with low light sensitivity. To address this issue, the authors tried to estimate the effective day length, i.e., the duration of the photoperiod that exceeds a certain threshold of light intensity. Continual global solar radiation observation data were gathered from the baseline surface radiation network (BSRN) of 18 sites from 2004 to 2007 and were converted to illuminance data using a luminous efficiency model. The monthly average of daily photoperiods exceeding each defined intensity (1 lx, 300 lx, … 20,000 lx) were calculated [defined as Ne(() (lux) ())]. The relationships between the monthly average of global solar radiation (Rs), N(0), and Ne(() (lux) ()) were investigated. At low light intensity (<500 lx), Ne(() (lux) ()) were almost the same as N(0). At high light intensity (>10,000 lx), Ne(() (lux) ()) and Rs showed a logarithmic relationship. Using these relationships, empirical models were derived to estimate the effective day length at different light intensities. According to the validation of the model, the effective day length for any light intensity could be estimated with an accuracy of less than 11% of the mean absolute percentage error (MAPE) in the estimation of the monthly base photoperiod. Recently, a number of studies have provided support for a link between day length and some diseases. Our results will be useful in further assessing the relationships between day length and these diseases.

Effect of ranibizumab on high-speed indocyanine green angiography and minimum intensity projection optical coherence tomography findings in neovascular age-related macular degeneration.

PubMed

Nicholson, Benjamin P; Nigam, Divya; Toy, Brian; Stetson, Paul F; Agrón, Elvira; Jacobs-El, Naima; Cunningham, Denise; Cukras, Catherine; Wong, Wai; Wiley, Henry; Chew, Emily; Ferris, Frederick; Meyerle, Catherine B

2015-01-01

The purpose of this 1-year prospective study was to investigate how induction/pro re nata ranibizumab intravitreal treatment of eyes with neovascular age-related macular degeneration affects the anatomy of choroidal neovascularization (CNV) and the overlying outer retinal tissue. High-speed indocyanine green (HS-ICG) angiography measurements provided quantification of the CNV size in 60 patients followed for 1 year. Minimum intensity projection optical coherence tomography (MinIP OCT), a novel algorithm assessing minimum optical intensity between the internal limiting membrane and retinal pigment epithelium, measured the area of outer retinal disruption overlying the CNV. Fluorescein angiography was also assessed to evaluate late retinal leakage. After 1 year, the mean area of CNV measured with indocyanine green angiography decreased by 5.8%. The mean area of MinIP OCT of outer retinal disruption overlying the CNV decreased by 4.2%. Mean area of fluorescein angiography leakage decreased by 6.3%. Both the area of outer retinal disruption measured with MinIP OCT and the area of leakage on fluorescein angiography typically exceeded the area of CNV on indocyanine green angiography at baseline and 1 year. Choroidal neovascularization treated with induction/pro re nata intravitreal ranibizumab for 1 year essentially remained static. Minimum intensity projection optical coherence tomography suggests that the area of outer retinal disruption overlying the CNV may be greater than the CNV itself and often correlates with the leakage area on fluorescein angiography. Additionally, there was minimal change in the area of outer retinal disruption on MinIP OCT even when fluid resolved. Measurements of the extent of CNV lesions based on indocyanine green angiography and MinIP OCT may provide useful outcome variables to help assess the CNV complex longitudinally and warrant further validation.

Vocal Parameters of Elderly Female Choir Singers

PubMed Central

Aquino, Fernanda Salvatico de; Ferreira, Léslie Piccolotto

2015-01-01

Introduction Due to increased life expectancy among the population, studying the vocal parameters of the elderly is key to promoting vocal health in old age. Objective This study aims to analyze the profile of the extension of speech of elderly female choristers, according to age group. Method The study counted on the participation of 25 elderly female choristers from the Choir of Messianic Church of São Paulo, with ages varying between 63 and 82 years, and an average of 71 years (standard deviation of 5.22). The elders were divided into two groups: G1 aged 63 to 71 years and G2 aged 72 to 82. We asked that each participant count from 20 to 30 in weak, medium, strong, and very strong intensities. Their speech was registered by the software Vocalgrama that allows the evaluation of the profile of speech range. We then submitted the parameters of frequency and intensity to descriptive analysis, both in minimum and maximum levels, and range of spoken voice. Results The average of minimum and maximum frequencies were respectively 134.82–349.96 Hz for G1 and 137.28–348.59 Hz for G2; the average for minimum and maximum intensities were respectively 40.28–95.50 dB for G1 and 40.63–94.35 dB for G2; the vocal range used in speech was 215.14 Hz for G1 and 211.30 Hz for G2. Conclusion The minimum and maximum frequencies, maximum intensity, and vocal range presented differences in favor of the younger elder group. PMID:26722341

Proton Fluxes Measured by the PAMELA Experiment from the Minimum to the Maximum Solar Activity for Solar Cycle 24

NASA Astrophysics Data System (ADS)

Martucci, M.; Munini, R.; Boezio, M.; Di Felice, V.; Adriani, O.; Barbarino, G. C.; Bazilevskaya, G. A.; Bellotti, R.; Bongi, M.; Bonvicini, V.; Bottai, S.; Bruno, A.; Cafagna, F.; Campana, D.; Carlson, P.; Casolino, M.; Castellini, G.; De Santis, C.; Galper, A. M.; Karelin, A. V.; Koldashov, S. V.; Koldobskiy, S.; Krutkov, S. Y.; Kvashnin, A. N.; Leonov, A.; Malakhov, V.; Marcelli, L.; Marcelli, N.; Mayorov, A. G.; Menn, W.; Mergè, M.; Mikhailov, V. V.; Mocchiutti, E.; Monaco, A.; Mori, N.; Osteria, G.; Panico, B.; Papini, P.; Pearce, M.; Picozza, P.; Ricci, M.; Ricciarini, S. B.; Simon, M.; Sparvoli, R.; Spillantini, P.; Stozhkov, Y. I.; Vacchi, A.; Vannuccini, E.; Vasilyev, G.; Voronov, S. A.; Yurkin, Y. T.; Zampa, G.; Zampa, N.; Potgieter, M. S.; Raath, J. L.

2018-02-01

Precise measurements of the time-dependent intensity of the low-energy (<50 GeV) galactic cosmic rays (GCRs) are fundamental to test and improve the models that describe their propagation inside the heliosphere. In particular, data spanning different solar activity periods, i.e., from minimum to maximum, are needed to achieve comprehensive understanding of such physical phenomena. The minimum phase between solar cycles 23 and 24 was peculiarly long, extending up to the beginning of 2010 and followed by the maximum phase, reached during early 2014. In this Letter, we present proton differential spectra measured from 2010 January to 2014 February by the PAMELA experiment. For the first time the GCR proton intensity was studied over a wide energy range (0.08–50 GeV) by a single apparatus from a minimum to a maximum period of solar activity. The large statistics allowed the time variation to be investigated on a nearly monthly basis. Data were compared and interpreted in the context of a state-of-the-art three-dimensional model describing the GCRs propagation through the heliosphere.

Inhibition of enteric pathogens and surrogates using integrated, high intensity 405nm led light on the surface of almonds

USDA-ARS?s Scientific Manuscript database

The disinfecting properties of 405 nm light were investigated against Escherichia coli O157:H7, Salmonella, and their non-pathogenic surrogate bacteria on the surface of almonds. High intensity monochromatic blue light (MBL) was generated from an array of narrow-band 405 nm light-emitting diodes (LE...

GAS PHOTOTUBE CIRCUIT

DOEpatents

Richardson, J.H.

1958-03-01

This patent pertains to electronic circuits for measuring the intensity of light and is especially concerned with measurement between preset light thresholds. Such a circuit has application in connection with devices for reading-out information stored on punch cards or tapes where the cards and tapes are translucent. By the novel arrangement of this invention thc sensitivity of a gas phototube is maintained at a low value when the light intensity is below a first threshold level. If the light level rises above the first threshold level, the tube is rendered highly sensitive and an output signal will vary in proportion to the light intensity change. When the light level decreases below a second threshold level, the gas phototube is automatically rendered highly insensitive. Each of these threshold points is adjustable.

Influence of light intensity on surface free energy and dentin bond strength of core build-up resins.

PubMed

Shimizu, Y; Tsujimoto, A; Furuichi, T; Suzuki, T; Tsubota, K; Miyazaki, M; Platt, J A

2015-01-01

We examined the influence of light intensity on surface free energy characteristics and dentin bond strength of dual-cure direct core build-up resin systems. Two commercially available dual-cure direct core build-up resin systems, Clearfil DC Core Automix with Clearfil Bond SE One and UniFil Core EM with Self-Etching Bond, were studied. Bovine mandibular incisors were mounted in acrylic resin and the facial dentin surfaces were wet ground on 600-grit silicon carbide paper. Adhesives were applied to dentin surfaces and cured with light intensities of 0 (no irradiation), 200, 400, and 600 mW/cm(2). The surface free energy of the adhesives (five samples per group) was determined by measuring the contact angles of three test liquids placed on the cured adhesives. To determine the strength of the dentin bond, the core build-up resin pastes were condensed into the mold on the adhesive-treated dentin surfaces according to the methods described for the surface free energy measurement. The resin pastes were cured with the same light intensities as those used for the adhesives. Ten specimens per group were stored in water maintained at 37°C for 24 hours, after which they were shear tested at a crosshead speed of 1.0 mm/minute in a universal testing machine. Two-way analysis of variance (ANOVA) and a Tukey-Kramer test were performed, with the significance level set at 0.05. The surface free energies of the adhesive-treated dentin surfaces decreased with an increase in the light intensity of the curing unit. Two-way ANOVA revealed that the type of core build-up system and the light intensity significantly influence the bond strength, although there was no significant interaction between the two factors. The highest bond strengths were achieved when the resin pastes were cured with the strongest light intensity for all the core build-up systems. When polymerized with a light intensity of 200 mW/cm(2) or less, significantly lower bond strengths were observed. CONClUSIONS: The data suggest that the dentin bond strength of core build-up systems are still affected by the light intensity of the curing unit, which is based on the surface free energy of the adhesives. On the basis of the results and limitations of the test conditions used in this study, it appears that a light intensity of >400 mW/cm(2) may be required for achieving the optimal dentin bond strength.

Representation of chromatic distribution for lighting system

NASA Astrophysics Data System (ADS)

Rossi, Maurizio; Musante, Fulvio

2015-01-01

For the luminaire manufacturer, the measurement of the lighting intensity distribution (LID) emitted by lighting fixture is based on photometry. So light is measured as an achromatic value of intensity and there is no the possibility to discriminate the measurement of white vs. colored light. At the Laboratorio Luce of Politecnico di Milano a new instrument for the measurement of spectral radiant intensities distribution for lighting system has been built: the goniospectra- radiometer. This new measuring tool is based on a traditional mirror gonio-photometer with a CCD spectraradiometer controlled by a PC. Beside the traditional representation of photometric distribution we have introduced a new representation where, in addition to the information about the distribution of luminous intensity in space, new details about the chromaticity characteristic of the light sources have been implemented. Some of the results of this research have been applied in developing and testing a new line of lighting system "My White Light" (the research project "Light, Environment and Humans" funded in the Italian Lombardy region Metadistretti Design Research Program involving Politecnico di Milano, Artemide, Danese, and some other SME of the Lighting Design district), giving scientific notions and applicative in order to support the assumption that colored light sources can be used for the realization of interior luminaries that, other than just have low power consumption and long life, may positively affect the mood of people.

Sound intensity probe for ultrasonic field in water using light-emitting diodes and piezoelectric elements

NASA Astrophysics Data System (ADS)

Zeng, Xi; Mizuno, Yosuke; Nakamura, Kentaro

2017-12-01

The sound intensity vector provides useful information on the state of an ultrasonic field in water, since sound intensity is a vector quantity expressing the direction and magnitude of the sound field. In the previous studies on sound intensity measurement in water, conventional piezoelectric sensors and metal cables were used, and the transmission distance was limited. A new configuration of a sound intensity probe suitable for ultrasonic measurement in water is proposed and constructed for trial in this study. The probe consists of light-emitting diodes and piezoelectric elements, and the output signals are transmitted through fiber optic cables as intensity-modulated light. Sound intensity measurements of a 26 kHz ultrasonic field in water are demonstrated. The difference in the intensity vector state between the water tank with and without sound-absorbing material on its walls was successfully observed.

Dose-dependent collagen cross-linking of rabbit scleral tissue by blue light and riboflavin treatment probed by dynamic shear rheology.

PubMed

Schuldt, Carsten; Karl, Anett; Körber, Nicole; Koch, Christian; Liu, Qing; Fritsch, Anatol W; Reichenbach, Andreas; Wiedemann, Peter; Käs, Josef A; Francke, Mike; Iseli, Hans Peter

2015-08-01

To determine the visco-elastic properties of isolated rabbit scleral tissue and dose-dependent biomechanical and morphological changes after collagen cross-linking by riboflavin/blue light treatment. Scleral patches from 87 adult albino rabbit eyes were examined by dynamic shear rheology. Scleral patches were treated by riboflavin and different intensities of blue light (450 nm), and the impact on the visco-elastic properties was determined by various rheological test regimes. The relative elastic modulus was calculated from non-treated and corresponding treated scleral patches, and treatments with different blue light intensities were compared. Shear rheology enables us to study the material properties of scleral tissue within physiological relevant parameters. Cross-linking treatment increased the viscous as well as the elastic modulus and changed the ratio of the elastic versus viscous proportion in scleral tissue. Constant riboflavin application combined with different blue light intensities from 12 mW/cm(2) up to 100 mW/cm(2) increased the relative elastic modulus of scleral tissue by factors up to 1.8. Further enhancement of the applied light intensity caused a decline of the relative elastic modulus. This might be due to destructive changes of the collagen bundle structure at larger light intensities, as observed by histological examination. Collagen cross-linking by riboflavin/blue light application increases the biomechanical stiffness of the sclera in a dose-dependent manner up to certain light intensities. Therefore, this treatment might be a suitable therapeutic approach to stabilize the biomechanical properties of scleral tissue in cases of pathological eye expansion. © 2014 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Resolving the Cygnus X-3 iron K line

NASA Technical Reports Server (NTRS)

Kitamoto, Shunji; Kawashima, Kenji; Negoro, Hitoshi; Miyamoto, Sigenori; White, N. E.; Nagase, Fumiaki

1994-01-01

An Advanced Satellite for Cosmology and Astrophysics (ASCA) observation of Cygnus X-3 on 1993 June 11, in its X-ray high intensity state, has for the first time resolved the broad iron K line emission into three components: a He-like line at 6.67 +/- 0.01 keV, a H-like line at 6.96 +/- 0.02 keV, and a neutral line at 6.37 +/- 0.03 keV. The line intensities of the 6.67 keV and 6.96 keV lines are modulated with the 4.8 hr orbital period and are maximum when the continuum intensity is minimum. There is a sharp minimum of the line intensity on the rising phase of the continuum intensity. An iron absorption edge is observed at 7.19 +/- 0.02 keV. The optical depth of the absorption edge varies from 0.3 to 0.5 and is in anti-phase with the overall X-ray continuum modulation. The observed complexity of the iron K line region is greater than that had been assumed in previous spectral modeling based on observations with lower resolution detectors.

Gravity-dependent regulation of red light induced moss protonemata branching and gametophore bud formation

NASA Astrophysics Data System (ADS)

Ripetskyj, R. T.; Kit, N. A.

Isolated leafy shoots of the moss Pottia intermedia positioned horizontally on the agar surface in vertically oriented petri dishes regenerate unbranching negatively gravitropic protonemata on upper side of the regenerant. Gravity determines the site of regeneration not the process itself. White light of low intensity unsufficient to induce positive phototropism of dark-grown protonemata can, however, provoke their branching and gametophore bud formation (Ripetskyj et al., 1998; 1999). The presented experiments have been carried out with red light in Biological Research in Canisters/Light Emitting Diode (BRIC/LED) hardware developed at Kennedy Space Center, USA. Seven-day-old dark-grown negatively gravitropic secondary P. intermedia protonemata were positioned differently with respect to gravity vector and to the source of red light of low, 1 or 2 μ mol\\cdot m-2\\cdot s-1, intensities. The light induced intensive branching of the protonemata and gametophore bud formation initiation site of both processes as well as the direction of growth of branches and buds being depent on the position of protonemata with respect to gravity and light vectors. Vertically positioned, i.e. ungravistimulated, dark grown protonemata illuminated from one side with red light of 2 μ mol\\cdot m-2\\cdot s-1 intensity produced 96,9 ± 2,2% of side branches and buds growing directly towards the light source from the lit protonema side. Horizontally disposed protonemata irradiated from below with red light of the same intensity regenerate 31,7 ± 3,9% of branches and buds on the upper, i.e. shaded protonemata side, the upward growth of which should undoubtedly be determined by gravity. In vertically disposed protonemata illuminated with red light of 1 μ mol\\cdot m-2\\cdot s-1 intensity from aside 31,9 ± 5,5% of side branches and buds arised on shaded protonema side and grew away from the light. Illumination of the protonemata in horizontal position from below increased the number of upgrowing branches and buds on upper shaded protonemata side to 76,9 ± 2,4%. The results convincingly speak for stimulating effect of the interaction of gravity and red light of low intensity. Characteristically, the number of side branches and buds on upper side of horizontally disposed protonemata illuminated from below (76,9 ± 2,4%) or parallely to protonemata length from their tips (86,0 ± 5,3%) were slightly, however, statistically significantly, greater than in the case of illumination from above (62,9 ± 3,1%). The effect may be probably be explained by some intensification of gravity action with red light of low intensity from shading of upper cell side or from lighting parallelly with respect to the cell surface. This research was supported by NASA grant NN-09(R).

Plasmonic trace sensing below the photon shot noise limit

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pooser, Raphael C.; Lawrie, Benjamin J.

Plasmonic sensors are important detectors of biochemical trace compounds, but those that utilize optical readout are approaching their absolute limits of detection as defined by the Heisenberg uncertainty principle in both differential intensity and phase readout. However, the use of more general minimum uncertainty states in the form of squeezed light can push the noise floor in these sensors below the shot noise limit (SNL) in one analysis variable at the expense of another. Here, we demonstrate a quantum plasmonic sensor whose noise floor is reduced below the SNL in order to perform index of refraction measurements with sensitivities unobtainablemore » with classical plasmonic sensors. The increased signal-to-noise ratio can result in faster detection of analyte concentrations that were previously lost in the noise. As a result, these benefits are the hallmarks of a sensor exploiting quantum readout fields in order to manipulate the limits of the Heisenberg uncertainty principle.« less

Online learning in optical tomography: a stochastic approach

NASA Astrophysics Data System (ADS)

Chen, Ke; Li, Qin; Liu, Jian-Guo

2018-07-01

We study the inverse problem of radiative transfer equation (RTE) using stochastic gradient descent method (SGD) in this paper. Mathematically, optical tomography amounts to recovering the optical parameters in RTE using the incoming–outgoing pair of light intensity. We formulate it as a PDE-constraint optimization problem, where the mismatch of computed and measured outgoing data is minimized with same initial data and RTE constraint. The memory and computation cost it requires, however, is typically prohibitive, especially in high dimensional space. Smart iterative solvers that only use partial information in each step is called for thereafter. Stochastic gradient descent method is an online learning algorithm that randomly selects data for minimizing the mismatch. It requires minimum memory and computation, and advances fast, therefore perfectly serves the purpose. In this paper we formulate the problem, in both nonlinear and its linearized setting, apply SGD algorithm and analyze the convergence performance.

Vacuum birefringence detection in all-optical scenarios

NASA Astrophysics Data System (ADS)

Ataman, Stefan

2018-06-01

In this paper we propose an all-optical vacuum birefringence experiment and evaluate its feasibility for various scenarios. Many petawatt-class lasers became operational and many more are expected to enter operation in the near future, therefore unprecedented electromagnetic fields (EL˜1014-1015 V/m and intensities IL˜1021-1023W/cm 2 ) will become available for experiments. In our proposal a petawatt-class laser disturbs the quantum vacuum and creates a delay in a counterpropagating probe laser beam. Placing this delayed beam in one arm of a Mach-Zehnder interferometer (MZI), allows the measurement of the vacuum refraction coefficient via a phase shift. Coherent as well as squeezed light are both considered and the minimum phase sensitivity evaluated. We show that using existing technology with some moderately optimistic assumptions, at least part of the discussed scenarios are feasible for a vacuum birefringence detection experiment.

Remote detection of methane with a 1.66-microm diode laser.

PubMed

Uehara, K; Tai, H

1992-02-20

High-sensitivity real-time remote detection of methane in air with a 1.66-microm distributed-feedback diode laser operating at room temperature is demonstrated by laboratory simulations. The laser current was modulated at a high frequency of ~5 MHz, and the laser-center frequency was locked onto a methane-absorption line. The laser light directed toward the probed region was received after one-way transmission or further reflection from a topographic target. The methane absorption was detected by the second-harmonic component in the optical-power variation. The minimum-detectable concentration-path-length product in the transmission scheme was 0.3 part in 10(6) m for a signal averaging time of 1.3 s. In the reflection scheme, the amount of methane could be measured from the ratio of the fundamental and second-harmonic signal intensities independently of the received power.

Plasmonic trace sensing below the photon shot noise limit

DOE PAGES

Pooser, Raphael C.; Lawrie, Benjamin J.

2015-12-09

Plasmonic sensors are important detectors of biochemical trace compounds, but those that utilize optical readout are approaching their absolute limits of detection as defined by the Heisenberg uncertainty principle in both differential intensity and phase readout. However, the use of more general minimum uncertainty states in the form of squeezed light can push the noise floor in these sensors below the shot noise limit (SNL) in one analysis variable at the expense of another. Here, we demonstrate a quantum plasmonic sensor whose noise floor is reduced below the SNL in order to perform index of refraction measurements with sensitivities unobtainablemore » with classical plasmonic sensors. The increased signal-to-noise ratio can result in faster detection of analyte concentrations that were previously lost in the noise. As a result, these benefits are the hallmarks of a sensor exploiting quantum readout fields in order to manipulate the limits of the Heisenberg uncertainty principle.« less

Looking for light in the din: An examination of the circadian-disrupting properties of a medical intensive care unit.

PubMed

Danielson, Samantha J; Rappaport, Charles A; Loher, Michael K; Gehlbach, Brian K

2018-06-01

Critically ill patients exhibit profound disturbances of circadian rhythmicity, most commonly in the form of a phase delay. We investigated the specific zeitgeber properties of a medical intensive care unit to develop a model that explained these abnormalities. Prospective, observational study conducted during 2013-2014. Twenty-four-hour ambient light (lux, 672 hours) and sound pressure levels (dBA, 504 hours) were measured in patient rooms. Patients and families were surveyed regarding their perceptions of the environment. University-based adult medical intensive care unit. The timing and intensity of the ambient light-dark cycle and sound environment and the relationship of these measurements to patient/family perceptions. Twenty-four-hour light-dark cycles were extremely weak and phase delayed relative to the solar cycle. Morning light averaged 12.1 (4.8, 37.2) lux, when only 24.9% ± 10.9% of available light was utilised; yet patients and families did not identify low daytime light levels as problematic. Median noise levels were invariably excessive (nighttime 47.9 [45.0, 51.3] dBA) with minimal variation, consistent with the absence of a defined rest period. The intensive care unit functions as a near-constant routine protocol disconnected from solar time. Behavioural interventions to promote entrainment should be supported by objective measurements of light and sound. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ultra-Broad-Band Optical Parametric Amplifier or Oscillator

NASA Technical Reports Server (NTRS)

Strekalov, Dmitry; Matsko, Andrey; Savchenkov, Anatolly; Maleki, Lute

2009-01-01

A concept for an ultra-broad-band optical parametric amplifier or oscillator has emerged as a by-product of a theoretical study in fundamental quantum optics. The study was originally intended to address the question of whether the two-photon temporal correlation function of light [in particular, light produced by spontaneous parametric down conversion (SPDC)] can be considerably narrower than the inverse of the spectral width (bandwidth) of the light. The answer to the question was found to be negative. More specifically, on the basis of the universal integral relations between the quantum two-photon temporal correlation and the classical spectrum of light, it was found that the lower limit of two-photon correlation time is set approximately by the inverse of the bandwidth. The mathematical solution for the minimum two-photon correlation time also provides the minimum relative frequency dispersion of the down-converted light components; in turn, the minimum relative frequency dispersion translates to the maximum bandwidth, which is important for the design of an ultra-broad-band optical parametric oscillator or amplifier. In the study, results of an analysis of the general integral relations were applied in the case of an optically nonlinear, frequency-dispersive crystal in which SPDC produces collinear photons. Equations were found for the crystal orientation and pump wavelength, specific for each parametric-down-converting crystal, that eliminate the relative frequency dispersion of collinear degenerate (equal-frequency) signal and idler components up to the fourth order in the frequency-detuning parameter

Optical based tactile shear and normal load sensor

DOEpatents

Salisbury, Curt Michael

2015-06-09

Various technologies described herein pertain to a tactile sensor that senses normal load and/or shear load. The tactile sensor includes a first layer and an optically transparent layer bonded together. At least a portion of the first layer is made of optically reflective material. The optically transparent layer is made of resilient material (e.g., clear silicone rubber). The tactile sensor includes light emitter/light detector pair(s), which respectively detect either normal load or shear load. Light emitter(s) emit light that traverses through the optically transparent layer and reflects off optically reflective material of the first layer, and light detector(s) detect and measure intensity of reflected light. When a normal load is applied, the optically transparent layer compresses, causing a change in reflected light intensity. When shear load is applied, a boundary between optically reflective material and optically absorptive material is laterally displaced, causing a change in reflected light intensity.

Effect of light intensity on food detection in captive great fruit-eating bats, Artibeus lituratus (Chiroptera: Phyllostomidae).

PubMed

Gutierrez, Eduardo de A; Pessoa, Valdir F; Aguiar, Ludmilla M S; Pessoa, Daniel M A

2014-11-01

Bats are known for their well-developed echolocation. However, several experiments focused on the bat visual system have shown evidence of the importance of visual cues under specific luminosity for different aspects of bat biology, including foraging behavior. This study examined the foraging abilities of five female great fruit-eating bats, Artibeus lituratus, under different light intensities. Animals were given a series of tasks to test for discrimination between a food target against an inedible background, under light levels similar to the twilight illumination (18lx), the full moon (2lx) and complete darkness (0lx). We found that the bats required a longer time frame to detect targets under a light intensity similar to twilight, possibly due to inhibitory effects present under a more intense light level. Additionally, bats were more efficient at detecting and capturing targets under light conditions similar to the luminosity of a full moon, suggesting that visual cues were important for target discrimination. These results demonstrate that light intensity affects foraging behavior and enables the use of visual cues for food detection in frugivorous bats. This article is part of a Special Issue entitled: Neotropical Behaviour. Copyright © 2014 Elsevier B.V. All rights reserved.

Purifying synthetic high-strength wastewater by microalgae chlorella vulgaris under various light emitting diode wavelengths and intensities

PubMed Central

2013-01-01

The high-strength wastewater is now well known as a threat to the natural water since it is highly possible to arouse water eutrophication or algal blooms. The effects of various light emitting diode wavelengths and intensities on the microalgae biological wastewater treatment system was studied in this research. The various nutrient removals and economic efficiencies represented similar variation trends, and these variations under both high C and N loading treatments were similar too. The order for microalgae C. vulgaris reproduction in terms of dry weight and nutrient removal efficiency both were red > white > yellow > blue, under high carbon and nitrogen loading treatments, indicating that the red light was the optimum light wavelength. Furthermore, considering the optimal light intensity in terms of nutrient removal efficiency was 2500 and 2000 μmol/m2•s, while in terms of economic efficiency was 1000, 1500 and 2000 μmol/m2•s. Therefore, the optimum light intensity was found to be 2000 μmol/m2•s. In addition, the optimal experimental illumination time was determined as 120 h. The Chlorella vulgaris microalgae biological wastewater treatment system utilized in this research was able to purify the high-strength carbon and nitrogen wastewater effectively under optimum light wavelength and intensity. PMID:24499586

Light alters nociceptive effects of magnetic field shielding in mice: intensity and wavelength considerations

PubMed Central

Prato, Frank S; Desjardins-Holmes, Dawn; Keenliside, Lynn D; McKay, Julia C; Robertson, John A; Thomas, Alex W

2008-01-01

Previous experiments with mice have shown that repeated 1 hour daily exposure to an ambient magnetic field-shielded environment induces analgesia (antinociception). The exposures were carried out in the dark (less than 2.0×1016 photons s−1 m−2) during the mid-light phase of the diurnal cycle. However, if the mice were exposed in the presence of visible light (2.0×1018 photons s−1 m−2, 400–750 nm), then the analgesic effects of shielding were eliminated. Here, we show that this effect of light is intensity and wavelength dependent. Introduction of red light (peak at 635 nm) had little or no effect, presumably because mice do not have photoreceptors sensitive to red light above 600 nm in their eyes. By contrast, introduction of ultraviolet light (peak at 405 nm) abolished the effect, presumably because mice do have ultraviolet A receptors. Blue light exposures (peak at 465 nm) of different intensities demonstrate that the effect has an intensity threshold of approximately 12% of the blue light in the housing facility, corresponding to 5×1016 photons s−1 m−2 (integral). This intensity is similar to that associated with photoreceptor-based magnetoreception in birds and in mice stimulates photopic/cone vision. Could the detection mechanism that senses ambient magnetic fields in mice be similar to that in bird navigation? PMID:18583276

Methodological Considerations When Quantifying High-Intensity Efforts in Team Sport Using Global Positioning System Technology.

PubMed

Varley, Matthew C; Jaspers, Arne; Helsen, Werner F; Malone, James J

2017-09-01

Sprints and accelerations are popular performance indicators in applied sport. The methods used to define these efforts using athlete-tracking technology could affect the number of efforts reported. This study aimed to determine the influence of different techniques and settings for detecting high-intensity efforts using global positioning system (GPS) data. Velocity and acceleration data from a professional soccer match were recorded via 10-Hz GPS. Velocity data were filtered using either a median or an exponential filter. Acceleration data were derived from velocity data over a 0.2-s time interval (with and without an exponential filter applied) and a 0.3-second time interval. High-speed-running (≥4.17 m/s 2 ), sprint (≥7.00 m/s 2 ), and acceleration (≥2.78 m/s 2 ) efforts were then identified using minimum-effort durations (0.1-0.9 s) to assess differences in the total number of efforts reported. Different velocity-filtering methods resulted in small to moderate differences (effect size [ES] 0.28-1.09) in the number of high-speed-running and sprint efforts detected when minimum duration was <0.5 s and small to very large differences (ES -5.69 to 0.26) in the number of accelerations when minimum duration was <0.7 s. There was an exponential decline in the number of all efforts as minimum duration increased, regardless of filtering method, with the largest declines in acceleration efforts. Filtering techniques and minimum durations substantially affect the number of high-speed-running, sprint, and acceleration efforts detected with GPS. Changes to how high-intensity efforts are defined affect reported data. Therefore, consistency in data processing is advised.

The effect of low light intensity on the maintenance of circadian synchrony in human subjects

NASA Technical Reports Server (NTRS)

Winget, C. M.; Lyman, J.; Beljan, J. R.

1976-01-01

Experiments were conducted on six healthy male subjects aged 20-23 yr and exposed for 21 days in a confined regulated environment to 16L:8D light:dark cycle with a view toward determining whether the light environment of 16L:8D at the relatively low light intensity of 15 ft.c. is adequate for the maintenance of circadian synchrony in man. The light intensity was 100 ft.c. during the first seven days, reduced to 15 ft.c. during the next seven days, and increased again to 100 ft.c. during the last seven days. Rectal temperature (RT) and heart rate (HR) were recorded throughout the three phases. In the 100 ft.c. regime, the RT and HR rhythms remained stable and circadian throughout. It is shown that 15 ft.c. light intensity is at or below threshold for maintaining circadian synchrony of human physiologic rhythms marked by instability and internal desynchronization with degradation of performance and well-being.

Interactions between light intensity and phosphorus nutrition affect the phosphate-mining capacity of white lupin (Lupinus albus L.)

PubMed Central

Cheng, Lingyun; Tang, Xiaoyan; Vance, Carroll P.; White, Philip J.; Zhang, Fusuo; Shen, Jianbo

2014-01-01

Light intensity affects photosynthetic carbon (C) fixation and the supply of carbon to roots. To evaluate interactions between carbon supply and phosphorus (P) supply, effects of light intensity on sucrose accumulation, root growth, cluster root formation, carboxylate exudation, and P uptake capacity were studied in white lupin (Lupinus albus L.) grown hydroponically with either 200 µmol m–2 s–1 or 600 µmol m–2 s–1 light and a sufficient (50 µM P) or deficient (1 µM P) P supply. Plant biomass and root:shoot ratio increased with increasing light intensity, particularly when plants were supplied with sufficient P. Both low P supply and increasing light intensity increased the production of cluster roots and citrate exudation. Transcripts of a phosphoenol pyruvate carboxylase gene (LaPEPC3) in cluster roots (which is related to the exudation of citrate), transcripts of a phosphate transporter gene (LaPT1), and P uptake all increased with increasing light intensity, under both P-sufficient and P-deficient conditions. Across all four experimental treatments, increased cluster root formation and carboxylate exudation were associated with lower P concentration in the shoot and greater sucrose concentration in the roots. It is suggested that C in excess of shoot growth capabilities is translocated to the roots as sucrose, which serves as both a nutritional signal and a C-substrate for carboxylate exudation and cluster root formation. PMID:24723402

Marginal eyespots on butterfly wings deflect bird attacks under low light intensities with UV wavelengths.

PubMed

Olofsson, Martin; Vallin, Adrian; Jakobsson, Sven; Wiklund, Christer

2010-05-24

Predators preferentially attack vital body parts to avoid prey escape. Consequently, prey adaptations that make predators attack less crucial body parts are expected to evolve. Marginal eyespots on butterfly wings have long been thought to have this deflective, but hitherto undemonstrated function. Here we report that a butterfly, Lopinga achine, with broad-spectrum reflective white scales in its marginal eyespot pupils deceives a generalist avian predator, the blue tit, to attack the marginal eyespots, but only under particular conditions-in our experiments, low light intensities with a prominent UV component. Under high light intensity conditions with a similar UV component, and at low light intensities without UV, blue tits directed attacks towards the butterfly head. In nature, birds typically forage intensively at early dawn, when the light environment shifts to shorter wavelengths, and the contrast between the eyespot pupils and the background increases. Among butterflies, deflecting attacks is likely to be particularly important at dawn when low ambient temperatures make escape by flight impossible, and when insectivorous birds typically initiate another day's search for food. Our finding that the deflective function of eyespots is highly dependent on the ambient light environment helps explain why previous attempts have provided little support for the deflective role of marginal eyespots, and we hypothesize that the mechanism that we have discovered in our experiments in a laboratory setting may function also in nature when birds forage on resting butterflies under low light intensities.

Growth kinetics of the photosynthetic bacterium Chlorobium thiosulfatophilum in a fed-batch reactor.

PubMed

Kim, B W; Chang, H N; Kim, I K; Lee, K S

1992-08-01

Hydrogen sulfide dissolved in water can be converted to elementary sulfur or sulfate by the photosynthetic bacterium Chlorobium thiosulfatophilum. Substrate inhibition occurred at sulfide concentrations above 5.7 mM. Light inhibition was found at average light intensities of 40,000 lux in a sulfide concentration of 5 mM, where no substrate inhibition occurred. Light intensity, the most important growth parameter, was attenuated through both scattering by sulfur particles and absorption by the cells. Average cell and sulfur particle sizes were 1.1 and 9.4 microm, respectively. Cells contributed 10 times as much to the turbidity as sulfur particles of the same weight concentration. The light attenuation factor was mathematically modeled, considering both the absorption and scattering effects based on the Beer-Lambert law and the Rayleigh theory, which were introduced to the cell growth model. Optimal operational conditions relating feed rate vs. light intensity were obtained to suppress the accumulation of sulfate and sulfide and save light energy for 2- and 4-L fed-batch reactors. Light intensity should be greater for the same performance (H(2)S removal rate/unit cell concentration) in larger reactors due to the scaleup effect on light transmission. Knowledge of appropriate growth kinetics in photosynthetic fed-batch reactors was essential to increase feed rate and light intensity and therefore cell growth. A mathematical model was developed that describes the cell growth by considering the light attenuation factor due to scattering and absorption and the crowding effect of the cells. This model was in good agreement with the experimental results. (c) 1992 John Wiley & Sons, Inc.

Lower light intensity reduces larval aggression in matrinxã, Brycon amazonicus.

PubMed

Lopes, Ana Caroliny C; Villacorta-Correa, Marle Angélica; Carvalho, Thaís B

2018-06-01

Brycon amazonicus shows a high frequency of aggressive behavior, which can be a limiting factor in intensive farming systems. Environmental changes can modulate the social interactions of fish and reduce aggression during the different stages of production. Groups of three larvae at 12 h after hatching (HAH) were subjected to different levels of light intensity: low (17 ± 3 lx), intermediate (204 ± 12.17 lx) and high (1,613.33 ± 499.03 lx), with eight replicates for each level. The lower light intensity reduced the frequency of aggressive interactions and locomotor activity exhibited by the animals. Based on these results, light intensity modulates aggression in B. amazonicus larvae. Manipulation of this factor could improve the social conditions of this species during farming and contribute to the development of new production technologies. Copyright © 2018 Elsevier B.V. All rights reserved.

Filter Enhances Fluorescent-Penetrant-Inspecting Borescope

NASA Technical Reports Server (NTRS)

Molina, Orlando G.

1990-01-01

Slip-on eyepiece for commercial ultraviolet-light borescope reduces both amount of short-wave ultraviolet light that reaches viewer's eye and apparent intensity of unwanted reflections of white light from surfaces undergoing inspection. Fits on stock eyepiece of borescope, which illuminates surface inspected with intense ultraviolet light. Surface, which is treated with fluorescent dye, emits bright-green visible light wherever dye penetrates - in cracks and voids. Eyepiece contains deep-yellow Wratten 15 (G) filter, which attenuates unwanted light strongly but passes yellow-green fluorescence so defects seen clearly.

The effects of castration, preslaughter stress and zeranol implants on beef: Part 2-Cooking properties and flavor of loin steaks from bovine males.

PubMed

Jeremiah, L E; Newman, J A; Tong, A K; Gibson, L L

1988-01-01

A total of 144 male crossbred calves were allocated to four castration or implant treatments (unimplanted bulls; unimplanted steers; bulls implanted with zeranol at 100 days of age and reimplanted at intervals of 69, 93 and 56 days thereafter; bulls implanted with zeranol at 168 days of age and reimplanted at intervals of 93 and 56 days thereafter) and two preslaughter shipping treatments (minimum preslaughter stress, with cattle shipped and slaughtered within 4 h of leaving the feedlot pen; normal preslaughter stress, with cattle mixed, trucked 160 km, and slaughtered up to 24 h after leaving the feedlot pen). These cattle were slaughtered and striploin steaks were removed after 6 days of post-mortem aging. Evaluations of these steaks were then conducted using both an experienced laboratory taste panel and a highly trained professional flavor profile panel. Results indicated that: (1) steaks from bulls had higher cooking losses than their counterparts from steers, when minimum preslaughter stress was applied; and required longer cooking times under both preslaughter handling treatments; (2) steaks from unimplanted bulls had greater cooking losses and required longer cooking times than their counterparts from implanted bulls under normal preslaughter stress, but not under minimum preslaughter stress; (3) higher proportions of bull steaks than steer steaks contained inappropriate flavor character notes, under both minimum and normal levels of preslaughter stress; (4) both castration and preslaughter handling affected the intensity and order of appearance of specific flavor character notes; (5) the level of preslaughter stress significantly influenced the detection of specific flavor character notes in steaks from both bulls and steers; (6) steaks from steers under minimum preslaughter stress were rated significantly higher in flavor amplitude than their counterparts from bulls when under normal preslaughter stress, and steaks from steers under minimum preslaughter stress received higher flavor desirability scores than steaks from bulls under both minimum and normal preslaughter stress; (7) zeranol implants influenced the appearance and the order of appearance of specific flavor character notes under both minimum and normal levels of preslaughter stress; (8) both zeranol implants and the length of time animals were implanted appeared to increase the intensity of certain inappropriate character notes, and to decrease the intensity of certain appropriate character notes; (9) steaks from implanted bulls received lower flavor amplitude ratings than their counterparts from unimplanted bulls under normal preslaughter stress, but not under minimum preslaughter stress; (10) the level of preslaughter stress influenced both the appearance and order of appearance of specific flavor character notes in both implanted and unimplanted bull steaks; (11) the intensities of certain flavor character notes were influenced by differences in the level of preslaughter stress in both implanted and unimplanted bull steaks, and higher levels usually resulted in inappropriate character notes being more intense; (12) steaks from bulls in both implant groups received lower flavor amplitude ratings when normal preslaughter stress was applied, clearly indicating the deleterious effect of the combination of zeranol implants and normal preslaughter stress on bull beef flavor; and (13) the deleterious effect of the combination of zeranol implants and normal preslaughter stress on bull beef flavor could not be explaind on the basis of greater production of 'dark cutting' beef. Copyright © 1988. Published by Elsevier Ltd.

Phase inversion and frequency doubling of reflection high-energy electron diffraction intensity oscillations in the layer-by-layer growth of complex oxides

NASA Astrophysics Data System (ADS)

Mao, Zhangwen; Guo, Wei; Ji, Dianxiang; Zhang, Tianwei; Gu, Chenyi; Tang, Chao; Gu, Zhengbin; Nie*, Yuefeng; Pan, Xiaoqing

In situ reflection high-energy electron diffraction (RHEED) and its intensity oscillations are extremely important for the growth of epitaxial thin films with atomic precision. The RHEED intensity oscillations of complex oxides are, however, rather complicated and a general model is still lacking. Here, we report the unusual phase inversion and frequency doubling of RHEED intensity oscillations observed in the layer-by-layer growth of SrTiO3 using oxide molecular beam epitaxy. In contacts to the common understanding that the maximum(minimum) intensity occurs at SrO(TiO2) termination, respectively, we found that both maximum or minimum intensities can occur at SrO, TiO2, or even incomplete terminations depending on the incident angle of the electron beam, which raises a fundamental question if one can rely on the RHEED intensity oscillations to precisely control the growth of thin films. A general model including surface roughness and termination dependent mean inner potential qualitatively explains the observed phenomena, and provides the answer to the question how to prepare atomically and chemically precise surface/interfaces using RHEED oscillations for complex oxides. We thank National Basic Research Program of China (No. 11574135, 2015CB654901) and the National Thousand-Young-Talents Program.

Photosynthetic and physiological responses of native and exotic tidal woody seedlings to simulated tidal immersion

NASA Astrophysics Data System (ADS)

Wu, Tonggui; Gu, Shenhua; Zhou, Hefeng; Wang, G. Geoff; Cheng, Xiangrong; Yu, Mukui

2013-12-01

Hibiscus hamabo, a native tidal woody species, and Myrica cerifera, an exotic tidal woody species, have been widely planted on coastal beaches in subtropical China. However, whether there are differences in physiological response and tolerance to immersion between the two tidal species is still unknown. Our objectives were to evaluate differences in the photosynthetic and physiological responses to tidal immersion for the two species in the context of sea level rise. With increasing immersion, net photosynthesis, stomatal conductance, intercellular CO2 concentration, and light saturation point declined progressively for both species, whereas dark respiration and light compensation point showed the reverse trend. Lower variation was observed in H. hamabo than in M. cerifera for each index in the same treatment. Photosynthetic ability and utilization of light, especially under high light intensity, decreased for both species. Leaf soluble sugar and protein contents, and glycolate oxidase activity first increased and then decreased with increasing of immersion degree, with the higher values observed in the W4 (4 h duration, 15 cm depth) and W6 (6 h duration, 25 cm depth) treatments for H. hamabo, and W2 (2 h duration, 5 cm depth) and W4 treatments for M. cerifera. These findings indicate that H. hamabo has a better ability to keep the reduction of photosynthesis at a minimum through soluble substance regulated osmotic potential and avoiding excess light damage to the photosynthetic system through increased photorespiration, heat dissipation, chlorophyll fluorescence. Our results suggest that H. hamabo is more tolerant to tidal immersion than M. cerifera, and therefore it is better adapted to the anticipated sea level rise in future.

Development of integrated semiconductor optical sensors for functional brain imaging

NASA Astrophysics Data System (ADS)

Lee, Thomas T.

Optical imaging of neural activity is a widely accepted technique for imaging brain function in the field of neuroscience research, and has been used to study the cerebral cortex in vivo for over two decades. Maps of brain activity are obtained by monitoring intensity changes in back-scattered light, called Intrinsic Optical Signals (IOS), that correspond to fluctuations in blood oxygenation and volume associated with neural activity. Current imaging systems typically employ bench-top equipment including lamps and CCD cameras to study animals using visible light. Such systems require the use of anesthetized or immobilized subjects with craniotomies, which imposes limitations on the behavioral range and duration of studies. The ultimate goal of this work is to overcome these limitations by developing a single-chip semiconductor sensor using arrays of sources and detectors operating at near-infrared (NIR) wavelengths. A single-chip implementation, combined with wireless telemetry, will eliminate the need for immobilization or anesthesia of subjects and allow in vivo studies of free behavior. NIR light offers additional advantages because it experiences less absorption in animal tissue than visible light, which allows for imaging through superficial tissues. This, in turn, reduces or eliminates the need for traumatic surgery and enables long-term brain-mapping studies in freely-behaving animals. This dissertation concentrates on key engineering challenges of implementing the sensor. This work shows the feasibility of using a GaAs-based array of vertical-cavity surface emitting lasers (VCSELs) and PIN photodiodes for IOS imaging. I begin with in-vivo studies of IOS imaging through the skull in mice, and use these results along with computer simulations to establish minimum performance requirements for light sources and detectors. I also evaluate the performance of a current commercial VCSEL for IOS imaging, and conclude with a proposed prototype sensor.

Suppression of white light generation (supercontinuum) in biological media: a pilot study using human salivary proteins

NASA Astrophysics Data System (ADS)

Santhosh, C.; Dharmadhikari, A. K.; Alti, K.; Dharmadhikari, J. A.; Mathur, D.

2007-02-01

Propagation of ultrashort pulses of intense, infrared light through transparent medium gives rise to a visually spectacular phenomenon known as supercontinuum (white light) generation wherein the spectrum of transmitted light is very considerably broader than that of the incident light. We have studied the propagation of ultrafast (<45 fs) pulses of intense infrared light through biological media (water, and water doped with salivary proteins) which reveal that white light generation is severely suppressed in the presence of a major salivary protein, α-amylase.

Improved Optics For Quasi-Elastic Light Scattering

NASA Technical Reports Server (NTRS)

Cheung, Harry Michael

1995-01-01

Improved optical train devised for use in light-scattering measurements of quasi-elastic light scattering (QELS) and laser spectroscopy. Measurements performed on solutions, microemulsions, micellular solutions, and colloidal dispersions. Simultaneous measurements of total intensity and fluctuations in total intensity of light scattered from sample at various angles provides data used, in conjunction with diffusion coefficients, to compute sizes of particles in sample.

Method for identifying and probing phase transitions in materials

DOEpatents

Asay, Blaine W.; Henson, Bryan F.; Sander, Robert K.; Robinson, Jeanne M.; Son, Steven F.; Dickson, Peter M.

2002-01-01

The present invention includes a method for identifying and probing phase transitions in materials. A polymorphic material capable of existing in at least one non-centrosymmetric phase is interrogated with a beam of laser light at a chosen wavelength and frequency. A phase transition is induced in the material while it is interrogated. The intensity of light scattered by the material and having a wavelength equal to one half the wavelength of the interrogating laser light is detected. If the phase transition results in the production of a non-centrosymmetric phase, the intensity of this scattered light increases; if the phase transition results in the disappearance of a non-centrosymmetric phase, the intensity of this scattered light decreases.

Enhanced light extraction efficiency of GaN-based light-emittng diodes by nitrogen implanted current blocking layer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Yong Deok; Oh, Seung Kyu; Park, Min Joo

Highlights: • A nitrogen implanted current-blocking layer was successfully demonstrated. • Light-extraction efficiency and radiant intensity was increased by more than 20%. • Ion implantation was successfully implemented in GaN based light-emitting diodes. - Abstract: GaN-based light emitting diodes (LEDs) with a nitrogen implanted current-blocking layer (CBL) were successfully demonstrated for improving the light extraction efficiency (LEE) and radiant intensity. The LEE and radiant intensity of the LEDs with a shallow implanted CBL with nitrogen was greatly increased by more than 20% compared to that of a conventional LED without the CBL due to an increase in the effective currentmore » path, which reduces light absorption at the thick p-pad electrode. Meanwhile, deep implanted CBL with a nitrogen resulted in deterioration of the LEE and radiant intensity because of formation of crystal damage, followed by absorption of the light generated at the multi-quantum well(MQW). These results clearly suggest that ion implantation method, which is widely applied in the fabrication of Si based devices, can be successfully implemented in the fabrication of GaN based LEDs by optimization of implanted depth.« less

Arduino-based experiment demonstrating Malus’s law

NASA Astrophysics Data System (ADS)

Freitas, W. P. S.; Cena, C. R.; Alves, D. C. B.; Goncalves, A. M. B.

2018-05-01

Malus’s law states that the intensity of light after passing through two polarizers is proportional to the square of the cosine of the angle between the polarizers. We present a simple setup demonstrating this law. The novelty of our work is that we use a multi-turn potentiometer mechanically linked to one of the polarizers to measure the polarizer’s rotation angle while keeping the other polarizer fixed. Both the potentiometer and light sensor used to measure the transmitted light intensity are connected to an Arduino board so that the intensity of light is measured as a function of the rotation angle.

New findings regarding light intensity and its effects as a zeitgeber in the Sprague-Dawley rat

NASA Technical Reports Server (NTRS)

Tischler, A. C.; Winget, C. M.; Holley, D. C.; Deroshia, C. W.; Gott, J.; Mele, G.; Callahan, P. X.

1993-01-01

In most mammals, the suprachiasmatic nucleus of the anterior hypothalamus has been implicated as the central driving mechanism of circadian rhythmicity. The photic input from the retina, via the retino-hypothalamic tract, and modulation from the pineal gland help regulate the clock. In this study, we investigated the effects of low light intensity on the circadian system of the Sprague-Dawley rat. A series of light intensity experiments were conducted to determine if a light level of 0.1 Lux will maintain entrained circadian rhythms of feeding, drinking, and locomotor activity.

Point process analysis of noise in early invertebrate vision

PubMed Central

Vinnicombe, Glenn

2017-01-01

Noise is a prevalent and sometimes even dominant aspect of many biological processes. While many natural systems have adapted to attenuate or even usefully integrate noise, the variability it introduces often still delimits the achievable precision across biological functions. This is particularly so for visual phototransduction, the process responsible for converting photons of light into usable electrical signals (quantum bumps). Here, randomness of both the photon inputs (regarded as extrinsic noise) and the conversion process (intrinsic noise) are seen as two distinct, independent and significant limitations on visual reliability. Past research has attempted to quantify the relative effects of these noise sources by using approximate methods that do not fully account for the discrete, point process and time ordered nature of the problem. As a result the conclusions drawn from these different approaches have led to inconsistent expositions of phototransduction noise performance. This paper provides a fresh and complete analysis of the relative impact of intrinsic and extrinsic noise in invertebrate phototransduction using minimum mean squared error reconstruction techniques based on Bayesian point process (Snyder) filters. An integrate-fire based algorithm is developed to reliably estimate photon times from quantum bumps and Snyder filters are then used to causally estimate random light intensities both at the front and back end of the phototransduction cascade. Comparison of these estimates reveals that the dominant noise source transitions from extrinsic to intrinsic as light intensity increases. By extending the filtering techniques to account for delays, it is further found that among the intrinsic noise components, which include bump latency (mean delay and jitter) and shape (amplitude and width) variance, it is the mean delay that is critical to noise performance. As the timeliness of visual information is important for real-time action, this delay could potentially limit the speed at which invertebrates can respond to stimuli. Consequently, if one wants to increase visual fidelity, reducing the photoconversion lag is much more important than improving the regularity of the electrical signal. PMID:29077703

Investigation of Correlation Effects in Nonlinear Optics

NASA Astrophysics Data System (ADS)

Friberg, Stephen Richard

This thesis deals with intensity correlation measurement methods as they apply to the study of light generated by a parametric downconversion process. The correlation properties of light can be used to distinguish between quantum mechanical light and classical light, where quantum mechanical light is electromagnetic radiation that can be accurately described only by a theory that quantizes the field. Spontaneous parametric downconversion produces quantum mechanical light, and we investigate some of its properties. A unique aspect of downconverted light is that pairs of photons are emitted in an interval that can be made smaller than the resolving time of any photon counting apparatus. Our experiments indicate that the interval is not affected by the bandwidth of the pump laser, nor by the length of the crystal. It is apparently determined only by the bandwidth of the detection apparatus, which in our experiment implies that the photons are produced in less than 1 psec, which is much shorter than the 100 psec resolution of our detection apparatus. The normalized cross-correlation functions for spontaneous downconversion are inversely dependent on intensity, but the normalized auto-correlations are independent of intensity. Measurements of the magnitude of the cross -correlations for several different pump beam intensities confirm this relationship. One of the inequalities imposed by classical theory relates the magnitude of the auto-correlations to the magnitude of the cross-correlations. Because of the inverse intensity dependence, this inequality is violated, thereby showing the quantum mechanical nature of the downconverted light. As an application of the large cross-correlations in downconversion, we apply the process to an optical communication channel which transmits information via coincidences between two light beams. Because of the strong discrimination against background provided by this technique, the channel can operate with large amounts of background light. A demonstration experiment of this communication channel is described. A signal transmitted by intensity modulation of the downconverted light is received perfectly by a coincidence counter, but is invisible to a photon counter. Also, a new correlator has been designed and constructed to measure intensity correlation functions. It has been used to measure the correlation properties of a standing -wave, single-mode, inhomogeneously-broadened He:Ne laser as a function of detuning. Results show that detuning of the laser alters the correlation properties in a way that can not be accounted for by merely a change in the pump parameter. These effects should therefore be taken into account when measurements of the statistical properties of the light are made whenever the laser intensity is controlled by detuning.

Child Labour Remains "Massive Problem."

ERIC Educational Resources Information Center

World of Work, 2002

2002-01-01

Despite significant progress in efforts to abolish child labor, an alarming number of children are engaged in its worst forms. Although 106 million are engaged in acceptable labor (light work for those above the minimum age for employment), 246 million are involved in child labor that should be abolished (under minimum age, hazardous work). (JOW)

46 CFR 111.60-4 - Minimum cable conductor size.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 false Minimum cable conductor size. 111.60-4 Section 111.60-4 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS... conductor must be #18 AWG (0.82 mm2) or larger except— (a) Each power and lighting cable conductor must be...

46 CFR 111.60-4 - Minimum cable conductor size.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 false Minimum cable conductor size. 111.60-4 Section 111.60-4 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS... conductor must be #18 AWG (0.82 mm2) or larger except— (a) Each power and lighting cable conductor must be...

46 CFR 111.60-4 - Minimum cable conductor size.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 false Minimum cable conductor size. 111.60-4 Section 111.60-4 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS... conductor must be #18 AWG (0.82 mm2) or larger except— (a) Each power and lighting cable conductor must be...

Formation and Change of Chloroplast-Located Plant Metabolites in Response to Light Conditions.

PubMed

Chen, Yiyong; Zhou, Bo; Li, Jianlong; Tang, Hao; Tang, Jinchi; Yang, Ziyin

2018-02-26

Photosynthesis is the central energy conversion process for plant metabolism and occurs within mature chloroplasts. Chloroplasts are also the site of various metabolic reactions involving amino acids, lipids, starch, and sulfur, as well as where the production of some hormones takes place. Light is one of the most important environmental factors, acting as an essential energy source for plants, but also as an external signal influencing their growth and development. Plants experience large fluctuations in the intensity and spectral quality of light, and many attempts have been made to improve or modify plant metabolites by treating them with different light qualities (artificial lighting) or intensities. In this review, we discuss how changes in light intensity and wavelength affect the formation of chloroplast-located metabolites in plants.

Light illumination intensity dependence of photovoltaic parameter in polymer solar cells with ammonium heptamolybdate as hole extraction layer.

PubMed

Liu, Zhiyong; Niu, Shengli; Wang, Ning

2018-01-01

A low-temperature, solution-processed molybdenum oxide (MoO X ) layer and a facile method for polymer solar cells (PSCs) is developed. The PSCs based on a MoO X layer as the hole extraction layer (HEL) is a significant advance for achieving higher photovoltaic performance, especially under weaker light illumination intensity. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) measurements show that the (NH 4 ) 6 Mo 7 O 24 molecule decomposes and forms the molybdenum oxide (MoO X ) molecule when undergoing thermal annealing treatment. In this study, PSCs with the MoO X layer as the HEL exhibited better photovoltaic performance, especially under weak light illumination intensity (from 100 to 10mWcm -2 ) compared to poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS)-based PSCs. Analysis of the current density-voltage (J-V) characteristics at various light intensities provides information on the different recombination mechanisms in the PSCs with a MoO X and PEDOT:PSS layer as the HEL. That the slopes of the open-circuit voltage (V OC ) versus light illumination intensity plots are close to 1 unity (kT/q) reveals that bimolecular recombination is the dominant and weaker monomolecular recombination mechanism in open-circuit conditions. That the slopes of the short-circuit current density (J SC ) versus light illumination intensity plots are close to 1 reveals that the effective charge carrier transport and collection mechanism of the MoO X /indium tin oxide (ITO) anode is the weaker bimolecular recombination in short-circuit conditions. Our results indicate that MoO X is an alternative candidate for high-performance PSCs, especially under weak light illumination intensity. Copyright © 2017 Elsevier Inc. All rights reserved.

The Effects of Light Intensity, Casing Layers, and Layering Styles on Royal Sun Medicinal Mushroom, Agaricus brasiliensis (Higher Basidiomycetes) Cultivation in Turkey.

PubMed

Adanacioglu, Neşe; Boztok, Kaya; Akdeniz, Ramazan Cengiz

2015-01-01

The aim of this research is to evaluate the effects of light intensity, casing layers, and layering styles on the production of the culinary-medicinal mushroom Agaricus brasiliensis in Turkey. The experiments were designed in split-split plots and replicated twice. Three different light intensities-I1, 350 lux; I2, 450 lux; and I3, 750 lux-were used in main plots as environmental factors. A mixture of 4 different casing layers- peat (100%), peat-perlite (75%:25%), peat-clinoptilolite (75%:25%), and peat-perlite-clinoptilolite (60%:20%:20%)-were used at split plots and at split plots. S1, a flat, 3-cm casing layer; S2, a flat, 5-cm casing layer; and S3, casing soil ridges 10 cm wide × 4 cm high, 10 cm apart, were deposited on top of 1-cm overall soil casing layers. At the end of the harvest phase, the total yield was estimated per 100 kg of substrate. Biological efficiency (percentage) was determined from the fresh weight of the mushrooms and the dry weight of the compost at the end of the harvesting period. The highest total yield (7.2 kg/100 kg compost) and biological efficiency (27.63%) were achieved from I2 × peat-perlite-clinoptilolite × S2 treatment. Influence of light intensity, casing layer, layering style, and their interaction in treatments with color values (L*, a*, b*, chroma*, and hue*) also were examined. It has been shown that within color values, chroma* (saturation) values of mushroom caps were affected by light intensity, casing layer, and layering style treatments and light intensity × casing layer treatments and the brightness of mushroom caps tended to increase as light intensity increased.

Effects of aerobic exercise intensity on ambulatory blood pressure and vascular responses in resistant hypertension: a crossover trial.

PubMed

Santos, Lucas P; Moraes, Ruy S; Vieira, Paulo J C; Ash, Garrett I; Waclawovsky, Gustavo; Pescatello, Linda S; Umpierre, Daniel

2016-07-01

Resistant hypertension often exposes patients to poor blood pressure (BP) control, resulting in clinical vulnerability, possible need for device-based procedures (denervation) and increased therapy costs. Regular exercise markedly benefits patients with hypertension, including resistant patients. However, little is known about short-term exercise effects in resistant hypertension. To evaluate acute hemodynamic effects of exercise in resistant hypertension. After maximal exercise testing, 20 patients (54.0 ± 5.7 years, 30.2 ± 4.9 kg/m) with resistant hypertension participated in three crossover interventions, in random order, and on separate days: control (45' of rest), and light intensity and moderate intensity (45' of aerobic exercise at 50 and 75% of maximum heart rate, respectively). Ambulatory BP, forearm blood flow (with subsequent calculation of vascular resistance), and reactive hyperemia were measured before and after interventions trough venous occlusion plethysmography. Compared with control, both exercise intensities reduced ambulatory systolic pressure over 5 h (light: -7.7 ± 2.4 mmHg and moderate: -9.4 ± 2.8 mmHg, P < 0.01), whereas only light intensity reduced diastolic pressure (-5.7 ± 2.2 mmHg, P < 0.01). Light intensity also lowered systolic and diastolic pressures over 10-h daytime (-3.8 ± 1.3 and -4.0 ± 1.3 mmHg, respectively, P < 0.02), night-time (-6.0 ± 2.4 and -6.1 ± 1.6 mmHg, respectively, P < 0.05), and diastolic pressure over 19 h (-4.8 ± 1.2 mmHg, P < 0.01). Forearm blood flow changed (decreased) compared with baseline only at 50 min after light intensity (P < 0.05). After the control and light intensity sessions, vascular resistance increased at the end of 1 h, and after moderate intensity, it decreased only at the moment (∼2 min) immediately after intervention (P < 0.05). A single session of light or moderate aerobic exercise acutely reduces ambulatory BP in resistant hypertension, although benefits persist longer following light intensity.

Light-intensity modulator withstands high heat fluxes

NASA Technical Reports Server (NTRS)

Maples, H. G.; Strass, H. K.

1966-01-01

Mechanism modulates and controls the intensity of luminous radiation in light beams associated with high-intensity heat flux. This modulator incorporates two fluid-cooled, externally grooved, contracting metal cylinders which when rotated about their longitudinal axes present a circular aperture of varying size depending on the degree of rotation.

Nonlinear photomagnetism of metals: Theory of nonlinear photoinduced dc current

NASA Astrophysics Data System (ADS)

Afonin, V. V.; Gurevich, V. L.; Laiho, R.

1995-07-01

Photoinduced magnetic flux has recently been observed in normal metals exposed to light. This effect is partly due to the fact that the light reflected from a metal surface transfers to the conduction electrons some of its quasimomentum. This creates a dc surface current which, for an appropriate geometry, brings about the photomagnetic effect. There is another contribution to the current that is due to anisotropy of the probabilities of electron transitions induced by the light, in combination with diffuse reflection of the electrons at the surface. We present here a theory of the dependence of the photoinduced current on the intensity of light Q. We assume that the light intensity is either constant or the time scale of its variation is much larger than the inverse Rabi frequency corresponding to the interband electron transition. At comparatively low intensities the current is proportional to Q. At higher intensities it varies as Q1/2. The physical origin of such behavior is analyzed. Various factors that allow a lowering of the critical intensity for the onset of the nonlinear behavior are discussed.

Cavity electromagnetically induced transparency with Rydberg atoms

NASA Astrophysics Data System (ADS)

Bakar Ali, Abu; Ziauddin

2018-02-01

Cavity electromagnetically induced transparency (EIT) is revisited via the input probe field intensity. A strongly interacting Rydberg atomic medium ensemble is considered in a cavity, where atoms behave as superatoms (SAs) under the dipole blockade mechanism. Each atom in the strongly interacting Rydberg atomic medium (87 Rb) follows a three-level cascade atomic configuration. A strong control and weak probe field are employed in the cavity with the ensemble of Rydberg atoms. The features of the reflected and transmitted probe light are studied under the influence of the input probe field intensity. A transparency peak (cavity EIT) is revealed at a resonance condition for small values of input probe field intensity. The manipulation of the cavity EIT is reported by tuning the strength of the input probe field intensity. Further, the phase and group delay of the transmitted and reflected probe light are studied. It is found that group delay and phase in the reflected light are negative, while for the transmitted light they are positive. The magnitude control of group delay in the transmitted and reflected light is investigated via the input probe field intensity.

Sound Velocity and Diffraction Intensity Measurements Based on Raman-Nath Theory of the Interaction of Light and Ultrasound

ERIC Educational Resources Information Center

Neeson, John F.; Austin, Stephen

1975-01-01

Describes a method for the measurement of the velocity of sound in various liquids based on the Raman-Nath theory of light-sound interaction. Utilizes an analog computer program to calculate the intensity of light scattered into various diffraction orders. (CP)

Perceiving the Intensity of Light

ERIC Educational Resources Information Center

Purves, Dale; Williams, S. Mark; Nundy, Surajit; Lotto, R. Beau

2004-01-01

The relationship between luminance (i.e., the photometric intensity of light) and its perception (i.e., sensations of lightness or brightness) has long been a puzzle. In addition to the mystery of why these perceptual qualities do not scale with luminance in any simple way, "illusions" such as simultaneous brightness contrast, Mach bands,…

Photosynthetically supplemental lighting for vegetable crop production with super-bright laser diode

NASA Astrophysics Data System (ADS)

Hu, Yongguang; Li, Pingping; Shi, Jintong

2007-02-01

Although many artificial light sources like high-pressure sodium lamp, metal halide lamp, fluorescent lamp and so on are commonly used in horticulture, they are not widely applied because of the disadvantages of unreasonable spectra, high cost and complex control. Recently new light sources of light-emitting diode (LED) and laser diode (LD) are becoming more and more popular in the field of display and illumination with the improvement of material and manufacturing, long life-span and increasingly low cost. A new type of super-bright red LD (BL650, central wavelength is 650 nm) was selected to make up of the supplemental lighting panel, on which LDs were distributed with regular hexagon array. Drive circuit was designed to power it and adjust light intensity. System performance including temperature rise and light intensity distribution under different vertical/horizontal distances were tested. Photosynthesis of sweet pepper and eggplant leaf under LD was measured with LI-6400 to show the supplemental lighting effects. The results show that LD system can supply the maximum light intensity of 180 μmol/m2 •s at the distance of 50 mm below the panel and the temperature rise is little within 1 °C. Net photosynthetic rate became faster when LD system increased light intensity. Compared with sunlight and LED supplemental lighting system, LD's promotion on photosynthesis is in the middle. Thus it is feasible for LD light source to supplement light for vegetable crops. Further study would focus on the integration of LD and other artificial light sources.

Low light intensity effects on the growth, photosynthetic characteristics, antioxidant capacity, yield and quality of wheat (Triticum aestivum L.) at different growth stages in BLSS

NASA Astrophysics Data System (ADS)

Dong, Chen; Fu, Yuming; Liu, Guanghui; Liu, Hong

2014-06-01

Minimizing energy consumption and maximizing crop productivity are major challenges to growing plants in Bioregenerative Life Support System (BLSS) for future long-term space mission. As a primary source of energy, light is one of the most important environmental factors for plant growth. The purpose of this study is to investigate the effects of low light intensity at different stages on growth, pigment composition, photosynthetic efficiency, biological production and antioxidant defence systems of wheat (Triticum aestivum L.) cultivars during ontogenesis. Experiments were divided into 3 intensity-controlled stages according to growth period (a total of 65 days): seedling stage (first 20 days), heading and flowering stage (middle 30 days) and grain filling stage (last 15 days). Initial light condition of the control was 420 μmol m-2 s-1 and the light intensity increased with the growth of wheat plants. The light intensities of group I and II at the first stage and the last stage were adjusted to the half level of the control respectively. For group III, the first and the last stage were both adjusted to half level of the control. During the middle 30 days, all treatments were kept the same intensity. The results indicated that low-light treatment at seedling stage, biomass, nutritional contents, components of inedible biomass and healthy index (including peroxidase (POD) activity, malondialdehyde (MDA) and proline content) of wheat plants have no significant difference to the control. Furthermore, unit kilojoule yield of group I reached 0.591 × 10-3 g/kJ and induced the highest energy efficiency. However, low-light treatment at grain filling stage affected the final production significantly.

Effect of light Intensity and photoperiod on growth of Chlorella pyrenoidosa and CO2 Biofixation

NASA Astrophysics Data System (ADS)

Gunawan, Teuku Johar; Ikhwan, Yusni; Restuhadi, Fajar; Pato, Usman

2018-02-01

Microalgae have been viewed as one of potential solution for CO2 biofixation or CO2 sequestration. However, many factors need to be evaluated to support development of CO2 biofixation. One important environmental factor for the growth of micro algae is related with light requirement. The aim of this study was to evaluate the effect of light intensity and photoperiod on growth of Chlorellapyrenoidosa (C.pyrenoidosa) and CO2 biofixation. Experiments were carried out in 1000 mL semi batch photo bioreactors, purged continuously with air (0.034% CO2). An Experiment of Factorial Design was employed in which the light intensity was evaluated 4 level at 2000, 4000, 6000 and 8000 lux with 3 level of photo period at L/D (light /dark) 8 hours/16 hours; L/D 12 hours/12 hours and L/D 16 hours/8 hours. The result indicated that both light intensity and photo period had significant effect (p< 0.05) on growth of C. pyrenoidosa. However, the photo period showed stronger effect relative to light intensity on growth of C.pyrenoidosa within the range reviewed. The interaction between the two factors was indicative but statistically not significant. Best growth profile sustained at combination of L/D 16 hours/8 hours of photoperiod and light intensity of 8000 lux with the highest average biomass observed at 0.516 ± 0.069gr/L. An increase in CO2biofixation rate of around 2 times was also observed between highest setting (8000 lux; L/D 16/12 hours) relative to that of lowest setting (2000 lux; L/D 8/12 hours).

Transcriptome profiling of anthocyanin-related genes reveals effects of light intensity on anthocyanin biosynthesis in red leaf lettuce.

PubMed

Zhang, Yanzhao; Xu, Shuzhen; Cheng, Yanwei; Peng, Zhengfeng; Han, Jianming

2018-01-01

Red leaf lettuce ( Lactuca sativa L.) is popular due to its high anthocyanin content, but poor leaf coloring often occurs under low light intensity. In order to reveal the mechanisms of anthocyanins affected by light intensity, we compared the transcriptome of L. sativa L. var. capitata under light intensities of 40 and 100 μmol m -2 s -1 . A total of 62,111 unigenes were de novo assembled with an N50 of 1,681 bp, and 48,435 unigenes were functionally annotated in public databases. A total of 3,899 differentially expressed genes (DEGs) were detected, of which 1,377 unigenes were up-regulated and 2,552 unigenes were down-regulated in the high light samples. By Kyoto Encyclopedia of Genes and Genomes enrichment analysis, the DEGs were significantly enriched in 14 pathways. Using gene annotation and phylogenetic analysis, we identified seven anthocyanin structural genes, including CHS , CHI , F3H , F3'H , DFR , ANS , and 3GT , and two anthocyanin transport genes, GST and MATE . In terms of anthocyanin regulatory genes, five MYBs and one bHLH gene were identified. An HY5 gene was discovered, which may respond to light-signaling and regulate anthocyanin structural genes. These genes showed a log2FC of 2.7-9.0 under high irradiance, and were validated using quantitative real-time-PCR. In conclusion, our results indicated transcriptome variance in red leaf lettuce under low and high light intensity, and observed a anthocyanin biosynthesis and regulation pattern. The data should further help to unravel the molecular mechanisms of anthocyanins influenced by light intensity.

Full spectrum optical safeguard

DOEpatents

Ackerman, Mark R.

2008-12-02

An optical safeguard device with two linear variable Fabry-Perot filters aligned relative to a light source with at least one of the filters having a nonlinear dielectric constant material such that, when a light source produces a sufficiently high intensity light, the light alters the characteristics of the nonlinear dielectric constant material to reduce the intensity of light impacting a connected optical sensor. The device can be incorporated into an imaging system on a moving platform, such as an aircraft or satellite.

Sacrificial hydrogen generation from aqueous triethanolamine with Eosin Y-sensitized Pt/TiO2 photocatalyst in UV, visible and solar light irradiation.

PubMed

Chowdhury, Pankaj; Gomaa, Hassan; Ray, Ajay K

2015-02-01

In this paper, we have studied Eosin Y-sensitized sacrificial hydrogen generation with triethanolamine as electron donor in UV, visible, and solar light irradiation. Aeroxide TiO2 was loaded with platinum metal via solar photo-deposition method to reduce the electron hole recombination process. Photocatalytic sacrificial hydrogen generation was influenced by several factors such as platinum loading (wt%) on TiO2, solution pH, Eosin Y to Pt/TiO2 mass ratio, triethanolamine concentration, and light (UV, visible and solar) intensities. Detailed reaction mechanisms in visible and solar light irradiation were established. Oxidation of triethanolamine and formaldehyde formation was correlated with hydrogen generation in both visible and solar lights. Hydrogen generation kinetics followed a Langmuir-type isotherm with reaction rate constant and adsorption constant of 6.77×10(-6) mol min(-1) and 14.45 M(-1), respectively. Sacrificial hydrogen generation and charge recombination processes were studied as a function of light intensities. Apparent quantum yields (QYs) were compared for UV, visible, and solar light at four different light intensities. Highest QYs were attained at lower light intensity because of trivial charge recombination. At 30 mW cm(-2) we achieved QYs of 10.82%, 12.23% and 11.33% in UV, visible and solar light respectively. Copyright © 2014 Elsevier Ltd. All rights reserved.

Separate and Simultaneous Adjustment of Light Qualities in a Real Scene

PubMed Central

Pont, Sylvia C.; Heynderick, Ingrid

2017-01-01

Humans are able to estimate light field properties in a scene in that they have expectations of the objects’ appearance inside it. Previously, we probed such expectations in a real scene by asking whether a “probe object” fitted a real scene with regard to its lighting. But how well are observers able to interactively adjust the light properties on a “probe object” to its surrounding real scene? Image ambiguities can result in perceptual interactions between light properties. Such interactions formed a major problem for the “readability” of the illumination direction and diffuseness on a matte smooth spherical probe. We found that light direction and diffuseness judgments using a rough sphere as probe were slightly more accurate than when using a smooth sphere, due to the three-dimensional (3D) texture. We here extended the previous work by testing independent and simultaneous (i.e., the light field properties separated one by one or blended together) adjustments of light intensity, direction, and diffuseness using a rough probe. Independently inferred light intensities were close to the veridical values, and the simultaneously inferred light intensity interacted somewhat with the light direction and diffuseness. The independently inferred light directions showed no statistical difference with the simultaneously inferred directions. The light diffuseness inferences correlated with but contracted around medium veridical values. In summary, observers were able to adjust the basic light properties through both independent and simultaneous adjustments. The light intensity, direction, and diffuseness are well “readable” from our rough probe. Our method allows “tuning the light” (adjustment of its spatial distribution) in interfaces for lighting design or perception research. PMID:28203350

Interactive effects of photoperiod and light intensity on blood physiological and biochemical reactions of broilers grown to heavy weights.

PubMed

Olanrewaju, H A; Purswell, J L; Collier, S D; Branton, S L

2013-04-01

The effects of photoperiod, light intensity, and their interaction on blood acid-base balance, metabolites, and electrolytes in broiler chickens under environmentally controlled conditions were examined in 2 trials. A 3 × 3 factorial experiment in a randomized complete block design was used in this study. In each trial, all treatment groups were provided 23L:1D with 20 lx of intensity from placement to 7 d, and then subjected to the treatments. The 9 treatments consisted of 3 photoperiods [long/continuous (23L:1D) from d 8 to 56, regular/intermittent (2L:2D), and short/nonintermittent (8L:16D) from d 8 to 48 and 23L:1D from d 49 to 56, respectively] and exposure to 3 light intensities (10, 5.0, and 0.5 lx) from d 8 through d 56 at 50% RH. Feed and water were provided ad libitum. Venous blood samples were collected on d 7, 14, 28, 42, and 56. Main effects indicated that short/nonintermittent photoperiod significantly (P < 0.05) reduced BW, pH, partial pressure of O2, saturated O2, Na(+), K(+), Ca(2+), Cl(-), osmolality, triiodothyronine (T3), and total protein along with significantly (P < 0.05) elevated partial pressure of CO2, hematocrit, hemoglobin, and lactate concentrations. In addition, there were no effects of photoperiod on HCO3(-), glucose, anion gap, and thyroxine (T4). Plasma corticosterone was not affected by photoperiod, light intensity, or their interaction. There was no effect of light intensity on most of the blood variables examined. Acid-base regulation during photoperiod and light intensity exposure did not deteriorate despite a lower pH and higher partial pressure of CO2 with normal HCO3(-). These results indicate that continuous exposure of broiler chickens to varying light intensities had a minor effect on blood physiological variables, whereas the short photoperiod markedly affected most blood physiological variables without inducing physiological stress in broilers.

APSIDAL MOTION AND A LIGHT CURVE SOLUTION FOR 13 LMC ECCENTRIC ECLIPSING BINARIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zasche, P.; Wolf, M.; Vraštil, J.

2015-12-15

New CCD observations for 13 eccentric eclipsing binaries from the Large Magellanic Cloud were carried out using the Danish 1.54 m telescope located at the La Silla Observatory in Chile. These systems were observed for their times of minimum and 56 new minima were obtained. These are needed for accurate determination of the apsidal motion. Besides that, in total 436 times of minimum were derived from the photometric databases OGLE and MACHO. The O – C diagrams of minimum timings for these B-type binaries were analyzed and the parameters of the apsidal motion were computed. The light curves of thesemore » systems were fitted using the program PHOEBE, giving the light curve parameters. We derived for the first time relatively short periods of the apsidal motion ranging from 21 to 107 years. The system OGLE-LMC-ECL-07902 was also analyzed using the spectra and radial velocities, resulting in masses of 6.8 and 4.4 M{sub ⊙} for the eclipsing components. For one system (OGLE-LMC-ECL-20112), the third-body hypothesis was also used to describe the residuals after subtraction of the apsidal motion, resulting in a period of about 22 years. For several systems an additional third light was also detected, which makes these systems suspect for triplicity.« less

Ca²⁺ signal contributing to the synthesis and emission of monoterpenes regulated by light intensity in Lilium 'siberia'.

PubMed

Hu, Zenghui; Li, Tianjiao; Zheng, Jian; Yang, Kai; He, Xiangfeng; Leng, Pingsheng

2015-06-01

The floral scent is an important part of plant volatile compounds, and is influenced by environmental factors. The emission of monoterpenes of Lilium 'siberia' is regulated by light intensity, but the mechanism is large unknown. In this study, the expression of Li-mTPS, a monoterpene synthase gene in the tepals of Lilium 'siberia', and net Ca(2+) flux were investigated after exposure to different levels of light intensity (0, 100, 300, 600, 1000, and 1500 μmol m(-2) s(-1)). Moreover the effect of LaCl3 and ethylene glycol-bis-(2-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA) on the Li-mTPS expression, monoterpene emission, and net Ca(2+) flux were examined at 600 μmol m(-2) s(-1). The results showed that along with the enhancement of light intensity, the expression level of Li-mTPS increased gradually, and the net Ca(2+) influx was also enhanced showing a similar pattern. It was found that LaCl3 and EGTA effectively inhibited the increase in expression of Li-mTPS and the net Ca(2+) influx induced by light treatment. Moreover, the release amounts of monoterpenes decreased significantly after treatment with LaCl3 and EGTA. So it can be concluded that Ca(2+) signal contributed to the biosynthesis and emission of monoterpenes regulated by light intensity in Lilium 'siberia' tepals. The increased light intensity firstly triggered the Ca(2+) influx to cytoplasm, and then the gene expression of monoterpene synthases downstream was activated to regulate the biosynthesis and emission of monoterpenes. But in the signaling pathway other mechanisms were thought to be involved in the emission of monoterpenes regulated by light intensity, which need to be investigated in future research. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Fast algal eco-toxicity assessment: Influence of light intensity and exposure time on Chlorella vulgaris inhibition by atrazine and DCMU.

PubMed

Camuel, Alexandre; Guieysse, Benoit; Alcántara, Cynthia; Béchet, Quentin

2017-06-01

In order to develop a rapid assay suitable for algal eco-toxicity assessments under conditions representative of natural ecosystems, this study evaluated the short-term (<1h) response of algae exposed to atrazine and DCMU using oxygen productivity measurements. When Chlorella vulgaris was exposed to these herbicides under 'standard' low light intensity (as prescribed by OECD201 guideline), the 20min-EC 50 values recorded via oxygen productivity (atrazine: 1.32±0.07μM; DCMU: 0.31±0.005μM) were similar the 96-h EC 50 recorded via algal growth (atrazine: 0.56μM; DCMU: 0.41μM), and within the range of values reported in the literature. 20min-EC50 values increased by factors of 3.0 and 2.1 for atrazine and DCMU, respectively, when light intensity increased from 60 to 1400μmolm -2 s -1 of photosynthetically active radiation, or PAR. Further investigation showed that exposure time significantly also impacted the sensitivity of C. vulgaris under high light intensity (>840μmolm -2 s -1 as PAR) as the EC 50 for atrazine and DCMU decreased by up to 6.2 and 2.1 folds, respectively, after 50min of exposure at a light irradiance of 1400μmolm -2 s -1 as PAR. This decrease was particularly marked at high light intensities and low algae concentrations and is explained by the herbicide disruption of the electron transfer chain triggering photo-inhibition at high light intensities. Eco-toxicity assessments aiming to understand the potential impact of toxic compounds on natural ecosystems should therefore be performed over sufficient exposure times (>20min for C. vulgaris) and under light intensities relevant to these ecosystems. Copyright © 2017 Elsevier Inc. All rights reserved.

Light intensity alters the extent of arsenic toxicity in Helianthus annuus L. seedlings.

PubMed

Yadav, Geeta; Srivastava, Prabhat Kumar; Singh, Vijay Pratap; Prasad, Sheo Mohan

2014-06-01

The present study is aimed at assessing the extent of arsenic (As) toxicity under three different light intensities-optimum (400 μmole photon m(-2) s(-1)), sub-optimum (225 μmole photon m(-2) s(-1)), and low (75 μmole photon m(-2) s(-1))-exposed to Helianthus annuus L. var. DRSF-113 seedlings by examining various physiological and biochemical parameters. Irrespective of the light intensities under which H. annuus L. seedlings were grown, there was an As dose (low, i.e., 6 mg kg(-1) soil, As1; and high, i.e., 12 mg kg(-1) soil, As2)-dependent decrease in all the growth parameters, viz., fresh mass, shoot length, and root length. Optimum light-grown seedlings exhibited better growth performance than the sub-optimum and low light-grown seedlings; however, low light-grown plants had maximum root and shoot lengths. Accumulation of As in the plant tissues depended upon its concentration used, proximity of the plant tissue, and intensity of the light. Greater intensity of light allowed greater assimilation of photosynthates accompanied by more uptake of nutrients along with As from the medium. The levels of chlorophyll a, b, and carotenoids declined with increasing concentrations of As. Seedlings acquired maximum Chl a and b under optimum light which were more compatible to face As1 and As2 doses of As, also evident from the overall status of enzymatic (SOD, POD, CAT, and GST) and non-enzymatic antioxidant (Pro).

Ultraviolet radiation cataract: dose dependence

NASA Astrophysics Data System (ADS)

Soderberg, Per G.; Loefgren, Stefan

1994-07-01

Current safety limits for cataract development after acute exposure to ultraviolet radiation (UVR) are based on experiments analyzing experimental data with a quantal, effect-no effect, dose-response model. The present study showed that intensity of forward light scattering is better described with a continuous dose-response model. It was found that 3, 30 and 300 kJ/m2UVR300nm induces increased light scattering within 6 h. For all three doses the intensity of forward light scattering was constant after 6 h. The intensity of forward light scattering was proportional to the log dose of UVR300nm. There was a slight increase of the intensity of forward light scattering on the contralateral side in animals that received 300 kJ/m2. Altogether 72 Sprague-Dawley male rats were included. Half of the rats were exposed in vivo on one side to UVR300nm. The other half was kept as a control group, receiving the same treatment as exposed rats but without delivery of UVR300nm to the eye. Subgroups of the rats received either of the three doses. Rats were sacrificed at varying intervals after the exposure. The lenses were extracted and the forward light scattering was estimated. It is concluded that intensity of forward light scattering in the lens after exposure to UVR300nm should be described with a continuous dose-reponse model.

Fundamental study for scattering suppression in biological tissue using digital phase-conjugate light with intensity modulation

NASA Astrophysics Data System (ADS)

Toda, Sogo; Kato, Yuji; Kudo, Nobuki; Shimizu, Koichi

2017-04-01

For transillumination imaging of an animal body, we have attempted to suppress the scattering effect in a turbid medium. It is possible to restore the optical image before scattering using phase-conjugate light. We examined the effect of intensity information as well as the phase information for the restoration of the original light distribution. In an experimental analysis using animal tissue, the contributions of the phase- and the intensity-information to the image restoration through turbid medium were demonstrated.

The effect of luminous intensity on the attraction of phlebotomine sand flies to light traps.

PubMed

Lima-Neto, Abdias R; Costa-Neta, Benedita M; da Silva, Apoliana Araújo; Brito, Jefferson M; Aguiar, João V C; Ponte, Islana S; Silva, Francinaldo S

2018-05-04

To improve the efficiency of light traps in collecting phlebotomine sand flies, the potential effects of luminous intensity on the attraction of these insects to traps were evaluated. Sand flies were collected with Hooper Pugedo (HP) light traps fitted with 5-mm light-emitting diodes (LED) bulbs: green (520 nm wavelength-10,000, 15,000 and 20,000 millicandela (mcd) and blue (470 nm-4,000, 12,000 and 15,000 mcd). A total of 3,264 sand flies comprising 13 species were collected. The collected species were Lutzomyia longipalpis (Lutz & Neiva) (Diptera: Psychodidae) (52.48%), Evandromyia evandroi (Costa Lima & Antunes, 1939) (Diptera: Psychodidae) (32.90%) and Micropygomyia goiana (Martins, Falcão, & Silva) (Diptera: Psychodidae) (9.76%). An increase in luminous intensity of the LEDs increased the size of the sand fly catch. The lower luminous intensity of green (10,000 mcd) attracted an average of 13.7 ± 2.8 sand flies/trap per night and the other luminous intensities accounted for a mean of 24.1 ± 4.0 (15,000 mcd) and 28.2 ± 5.0 (20,000 mcd) sand flies/trap per night. Regarding the blue wavelength, the lower luminous intensity (4,000 mcd) attracted an average of 27.4 ± 4.1 sand flies/trap per night, followed by 12,000 mcd (37.6 ± 8.7) and 15,000 mcd (40.5 ± 7.3). Based on our data, the luminous intensity of light traps should be considered when developing light traps for monitoring or controlling phlebotomine sand flies.

Construction and temporal behaviour study of multi RLC intense light pulses for dermatological applications.

PubMed

Hamoudi, Walid K; Ismail, Raid A; Shakir, Hussein A

2017-10-01

Driving a flash lamp in an intense pulsed light system requires a high-voltage DC power supply, capacitive energy storage and a flash lamp triggering unit. Single, double, triple and quadruple-mesh discharge and triggering circuits were constructed to provide intense light pulses of variable energy and time durations. The system was treated as [Formula: see text] circuit in some cases and [Formula: see text] circuit in others with a light pulse profile following the temporal behaviour of the exciting current pulse. Distributing the energy delivered to one lamp onto a number of LC meshes permitted longer current pulses, and consequently increased the light pulse length. Positive results were obtained when using the system to treat skin wrinkles.

Interactions between light intensity and phosphorus nutrition affect the phosphate-mining capacity of white lupin (Lupinus albus L.).

PubMed

Cheng, Lingyun; Tang, Xiaoyan; Vance, Carroll P; White, Philip J; Zhang, Fusuo; Shen, Jianbo

2014-07-01

Light intensity affects photosynthetic carbon (C) fixation and the supply of carbon to roots. To evaluate interactions between carbon supply and phosphorus (P) supply, effects of light intensity on sucrose accumulation, root growth, cluster root formation, carboxylate exudation, and P uptake capacity were studied in white lupin (Lupinus albus L.) grown hydroponically with either 200 µmol m(-2) s(-1) or 600 µmol m(-2) s(-1) light and a sufficient (50 µM P) or deficient (1 µM P) P supply. Plant biomass and root:shoot ratio increased with increasing light intensity, particularly when plants were supplied with sufficient P. Both low P supply and increasing light intensity increased the production of cluster roots and citrate exudation. Transcripts of a phosphoenol pyruvate carboxylase gene (LaPEPC3) in cluster roots (which is related to the exudation of citrate), transcripts of a phosphate transporter gene (LaPT1), and P uptake all increased with increasing light intensity, under both P-sufficient and P-deficient conditions. Across all four experimental treatments, increased cluster root formation and carboxylate exudation were associated with lower P concentration in the shoot and greater sucrose concentration in the roots. It is suggested that C in excess of shoot growth capabilities is translocated to the roots as sucrose, which serves as both a nutritional signal and a C-substrate for carboxylate exudation and cluster root formation. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Metameric MIMO-OOK transmission scheme using multiple RGB LEDs.

PubMed

Bui, Thai-Chien; Cusani, Roberto; Scarano, Gaetano; Biagi, Mauro

2018-05-28

In this work, we propose a novel visible light communication (VLC) scheme utilizing multiple different red green and blue triplets each with a different emission spectrum of red, green and blue for mitigating the effect of interference due to different colors using spatial multiplexing. On-off keying modulation is considered and its effect on light emission in terms of flickering, dimming and color rendering is discussed so as to demonstrate how metameric properties have been considered. At the receiver, multiple photodiodes with color filter-tuned on each transmit light emitting diode (LED) are employed. Three different detection mechanisms of color zero forcing, minimum mean square error estimation and minimum mean square error equalization are then proposed. The system performance of the proposed scheme is evaluated both with computer simulations and tests with an Arduino board implementation.

32 CFR 634.20 - Privately owned vehicle operation requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... (CONTINUED) LAW ENFORCEMENT AND CRIMINAL INVESTIGATIONS MOTOR VEHICLE TRAFFIC SUPERVISION Motor Vehicle... those requiring use. Inspections will meet minimum standards established by the National Highway Traffic Safety Administration (NHTSA) in 49 CFR 570.1 through 570.10. Lights, turn signals, brake lights, horn...

Demonstration of a simplified optical mouse lighting module by integrating the non-Lambertian LED chip and the free-form surface.

PubMed

Pan, Jui-Wen; Tu, Sheng-Han

2012-05-20

A cost-effective, high-throughput, and high-yield method for the efficiency enhancement of an optical mouse lighting module is proposed. We integrated imprinting technology and free-form surface design to obtain a lighting module with high illumination efficiency and uniform intensity distribution. The imprinting technique can increase the light extraction efficiency and modulate the intensity distribution of light-emitting diodes. A modulated light source was utilized to add a compact free-form surface element to create a lighting module with 95% uniformity and 80% optical efficiency.

Impact of different colours of artificial light at night on melatonin rhythm and gene expression of gonadotropins in European perch.

PubMed

Brüning, Anika; Hölker, Franz; Franke, Steffen; Kleiner, Wibke; Kloas, Werner

2016-02-01

The distribution and intensity of artificial light at night, commonly referred to as light pollution, is consequently rising and progressively also ecological implications come to light. Low intensity light is known to suppress nocturnal melatonin production in several fish species. This study aims to examine the least suppressive light colour for melatonin excreted into the holding water and the influence of different light qualities and quantities in the night on gene expression of gonadotropins in fish. European perch (Perca fluviatilis) were exposed to light of different wavelengths during the night (blue, green, and red). Melatonin concentrations were measured from water samples every 3h during a 24h period. Gene expression of gonadotropins was measured in perch exposed to different light colours and was additionally examined for perch subjected to different intensities of white light (0 lx, 1 lx, 10 lx, 100 lx) during the night. All different light colours caused a significant drop of melatonin concentration; however, blue light was least suppressive. Gene expression of gonadotropins was not influenced by nocturnal light of different light colours, but in female perch gonadotropin expression was significantly reduced by white light already at the lowest level (1 lx). We conclude that artificial light with shorter wavelengths at night is less effective in disturbing biological rhythms of perch than longer wavelengths, coinciding with the light situation in freshwater habitats inhabited by perch. Different light colours in the night showed no significant effect on gonadotropin expression, but white light in the night can disturb reproductive traits already at very low light intensities. These findings indicate that light pollution has not only the potential to disturb the melatonin cycle but also the reproductive rhythm and may therefore have implications on whole species communities. Copyright © 2015 Elsevier B.V. All rights reserved.

Is Low-Impact Aerobic Dance an Effective Cardiovascular Workout?

ERIC Educational Resources Information Center

Williford, Henry N.; And Others

1989-01-01

Presents results of an investigation comparing energy cost and cardiovascular responses of aerobic dance routines performed at different intensity levels in varying amounts of energy expenditure. For low-impact dance to meet minimum guidelines suggested by the American College of Sports Medicine, it should be performed at high intensity. (SM)

LED Lighting – Modification of Growth, Metabolism, Yield and Flour Composition in Wheat by Spectral Quality and Intensity

PubMed Central

Monostori, István; Heilmann, Márk; Kocsy, Gábor; Rakszegi, Marianna; Ahres, Mohamed; Altenbach, Susan B.; Szalai, Gabriella; Pál, Magda; Toldi, Dávid; Simon-Sarkadi, Livia; Harnos, Noémi; Galiba, Gábor; Darko, Éva

2018-01-01

The use of light-emitting diode (LED) technology for plant cultivation under controlled environmental conditions can result in significant reductions in energy consumption. However, there is still a lack of detailed information on the lighting conditions required for optimal growth of different plant species and the effects of light intensity and spectral composition on plant metabolism and nutritional quality. In the present study, wheat plants were grown under six regimens designed to compare the effects of LED and conventional fluorescent lights on growth and development, leaf photosynthesis, thiol and amino acid metabolism as well as grain yield and flour quality of wheat. Benefits of LED light sources over fluorescent lighting were manifested in both yield and quality of wheat. Elevated light intensities made possible with LEDs increased photosynthetic activity, the number of tillers, biomass and yield. At lower light intensities, blue, green and far-red light operated antagonistically during the stem elongation period. High photosynthetic activity was achieved when at least 50% of red light was applied during cultivation. A high proportion of blue light prolonged the juvenile phase, while the shortest flowering time was achieved when the blue to red ratio was around one. Blue and far-red light affected the glutathione- and proline-dependent redox environment in leaves. LEDs, especially in Blue, Pink and Red Low Light (RedLL) regimens improved flour quality by modifying starch and protein content, dough strength and extensibility as demonstrated by the ratios of high to low molecular weight glutenins, ratios of glutenins to gliadins and gluten spread values. These results clearly show that LEDs are efficient for experimental wheat cultivation, and make it possible to optimize the growth conditions and to manipulate metabolism, yield and quality through modification of light quality and quantity. PMID:29780400

LED Lighting - Modification of Growth, Metabolism, Yield and Flour Composition in Wheat by Spectral Quality and Intensity.

PubMed

Monostori, István; Heilmann, Márk; Kocsy, Gábor; Rakszegi, Marianna; Ahres, Mohamed; Altenbach, Susan B; Szalai, Gabriella; Pál, Magda; Toldi, Dávid; Simon-Sarkadi, Livia; Harnos, Noémi; Galiba, Gábor; Darko, Éva

2018-01-01

The use of light-emitting diode (LED) technology for plant cultivation under controlled environmental conditions can result in significant reductions in energy consumption. However, there is still a lack of detailed information on the lighting conditions required for optimal growth of different plant species and the effects of light intensity and spectral composition on plant metabolism and nutritional quality. In the present study, wheat plants were grown under six regimens designed to compare the effects of LED and conventional fluorescent lights on growth and development, leaf photosynthesis, thiol and amino acid metabolism as well as grain yield and flour quality of wheat. Benefits of LED light sources over fluorescent lighting were manifested in both yield and quality of wheat. Elevated light intensities made possible with LEDs increased photosynthetic activity, the number of tillers, biomass and yield. At lower light intensities, blue, green and far-red light operated antagonistically during the stem elongation period. High photosynthetic activity was achieved when at least 50% of red light was applied during cultivation. A high proportion of blue light prolonged the juvenile phase, while the shortest flowering time was achieved when the blue to red ratio was around one. Blue and far-red light affected the glutathione- and proline-dependent redox environment in leaves. LEDs, especially in Blue, Pink and Red Low Light (RedLL) regimens improved flour quality by modifying starch and protein content, dough strength and extensibility as demonstrated by the ratios of high to low molecular weight glutenins, ratios of glutenins to gliadins and gluten spread values. These results clearly show that LEDs are efficient for experimental wheat cultivation, and make it possible to optimize the growth conditions and to manipulate metabolism, yield and quality through modification of light quality and quantity.

Techniques for optically compressing light intensity ranges

DOEpatents

Rushford, Michael C.

1989-01-01

A pin hole camera assembly for use in viewing an object having a relatively large light intensity range, for example a crucible containing molten uranium in an atomic vapor laser isotope separator (AVLIS) system is disclosed herein. The assembly includes means for optically compressing the light intensity range appearing at its input sufficient to make it receivable and decipherable by a standard video camera. A number of different means for compressing the intensity range are disclosed. These include the use of photogray glass, the use of a pair of interference filters, and the utilization of a new liquid crystal notch filter in combination with an interference filter.

Techniques for optically compressing light intensity ranges

DOEpatents

Rushford, M.C.

1989-03-28

A pin hole camera assembly for use in viewing an object having a relatively large light intensity range, for example a crucible containing molten uranium in an atomic vapor laser isotope separator (AVLIS) system is disclosed herein. The assembly includes means for optically compressing the light intensity range appearing at its input sufficient to make it receivable and decipherable by a standard video camera. A number of different means for compressing the intensity range are disclosed. These include the use of photogray glass, the use of a pair of interference filters, and the utilization of a new liquid crystal notch filter in combination with an interference filter. 18 figs.

Phytoplankton division rates in light-limited environments: two adaptations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rivkin, R.B.; Voytek, M.A.; Seliger, H.H.

1982-02-26

Red tide-forming dinoflagellates maximize cell numbers during periods of low light intensities in two ways. For short-term exposures to suboptimal light intensities such as might occur during recirculation in frontal convergences, cell division rates can be maintained at the expense of stored carbon for up to two generation times. During longer periods, corresponding to subsurface transport below a pycnocline, cell division rates eventually decrease as a portion of the fixed carbon is diverted to replenishing stored carbon. As a result, maximum rates of cell division can be resumed rapidly upon advection into surface waters where light intensities are optimal formore » growth.« less

DARK ADAPTATION IN DINEUTES

PubMed Central

Clark, Leonard B.

1938-01-01

The level of dark adaptation of the whirligig beetle can be measured in terms of the threshold intensity calling forth a response. The course of dark adaptation was determined at levels of light adaptation of 6.5, 91.6, and 6100 foot-candles. All data can be fitted by the same curve. This indicates that dark adaptation follows parts of the same course irrespective of the level of light adaptation. The intensity of the adapting light determines the level at which dark adaptation will begin. The relation between log aI 0 (instantaneous threshold) and log of adapting light intensity is linear over the range studied. PMID:19873056

Low-light divergence in photovoltaic parameter fluctuations

NASA Astrophysics Data System (ADS)

Shvydka, Diana; Karpov, V. G.; Compaan, A. D.

2003-03-01

We study statistics of the major photovoltaic (PV) parameters, such as open-circuit voltage, short-circuit current, etc., versus light intensity on a set of nominally identical thin-film CdTe/CdS solar cells. A crossover light intensity is found, below which the relative fluctuations of the PV parameters diverge inversely proportional to the square root of the light intensity. We propose a model in which the observed fluctuations are due to lateral nonuniformities in the device structure. The crossover is attributed to the lateral nonuniformity screening length exceeding the device size. From the practical standpoint, our study introduces a simple uniformity diagnostic technique.

K/Na-triggered bioluminescence in the oceanic squid Symplectoteuthis oualaniensis.

PubMed

Tsuji, F I; Leisman, G B

1981-11-01

A distinctive type of luminescent system present in the large dorsal luminous organ of the oceanic squid Symplectoteuthis oualaniensis is described. The organ produces an intense blue flash of light followed by a rapid decay in light intensity. Luminescence originates from numerous oval granules present in the luminous organ. The essential light-emitting components are membrane bound. Intact granules or washed homogenates of the granules are triggered to emit light by monovalent cations such as, in decreasing order of effectiveness, potassium, rubidium, sodium, cesium, ammonium, and lithium. Calcium, magnesium, and strontium ions do not trigger light emission. Analysis of the kinetics of the decay of light intensity suggests that two light-emitting components are involved, one decaying faster than the other. The light-emitting reaction has an absolute requirement for molecular oxygen. The optimum KCl or NaCl concentration is approximately 0.6 M and the optimum pH is approximately 7.8. A free sulfhydryl group is essential for activity.

Low-intensity calibration source for optical imaging systems

NASA Astrophysics Data System (ADS)

Holdsworth, David W.

2017-03-01

Laboratory optical imaging systems for fluorescence and bioluminescence imaging have become widely available for research applications. These systems use an ultra-sensitive CCD camera to produce quantitative measurements of very low light intensity, detecting signals from small-animal models labeled with optical fluorophores or luminescent emitters. Commercially available systems typically provide quantitative measurements of light output, in units of radiance (photons s-1 cm-2 SR-1) or intensity (photons s-1 cm-2). One limitation to current systems is that there is often no provision for routine quality assurance and performance evaluation. We describe such a quality assurance system, based on an LED-illuminated thin-film transistor (TFT) liquid-crystal display module. The light intensity is controlled by pulse-width modulation of the backlight, producing radiance values ranging from 1.8 x 106 photons s-1 cm-2 SR-1 to 4.2 x 1013 photons s-1 cm-2 SR-1. The lowest light intensity values are produced by very short backlight pulses (i.e. approximately 10 μs), repeated every 300 s. This very low duty cycle is appropriate for laboratory optical imaging systems, which typically operate with long-duration exposures (up to 5 minutes). The low-intensity light source provides a stable, traceable radiance standard that can be used for routine quality assurance of laboratory optical imaging systems.

Characterization of highly scattering media by measurement of diffusely backscattered polarized light

DOEpatents

Hielscher, Andreas H.; Mourant, Judith R.; Bigio, Irving J.

2000-01-01

An apparatus and method for recording spatially dependent intensity patterns of polarized light that is diffusely backscattered from highly scattering media are described. These intensity patterns can be used to differentiate different turbid media, such as polystyrene-sphere and biological-cell suspensions. Polarized light from a He-Ne laser (.lambda.=543 nm) is focused onto the surface of the scattering medium, and a surface area of approximately 4.times.4 cm centered on the light input point is imaged through polarization analysis optics onto a CCD camera. A variety of intensity patterns may be observed by varying the polarization state of the incident laser light and changing the analyzer configuration to detect different polarization components of the backscattered light. Experimental results for polystyrene-sphere and Intralipid suspensions demonstrate that the radial and azimuthal variations of the observed pattern depend on the concentration, size, and anisotropy factor, g, of the particles constituting the scattering medium. Measurements performed on biological cell suspensions show that intensity patterns can be used to differentiate between suspensions of cancerous and non-cancerous cells. Introduction of the Mueller-matrix for diffusely backscattered light, permits the selection of a subset of measurements which comprehensively describes the optical properties of backscattering media.

Algal culture studies for CELSS

NASA Technical Reports Server (NTRS)

Radmer, R.; Behrens, P.; Arnett, K.; Gladue, R.; Cox, J.; Lieberman, D.

1987-01-01

Microalgae are well-suited as a component of a Closed Environmental Life Support System (CELSS), since they can couple the closely related functions of food production and atmospheric regeneration. The objective was to provide a basis for predicting the response of CELSS algal cultures, and thus the food supply and air regeneration system, to changes in the culture parameters. Scenedesmus growth was measured as a function of light intensity, and the spectral dependence of light absorption by the algae as well as algal respiration in the light were determined as a function of cell concentration. These results were used to test and confirm a mathematical model that describes the productivity of an algal culture in terms of the competing processes of photosynthesis and respiration. The relationship of algal productivity to cell concentration was determined at different carbon dioxide concentrations, temperatures, and light intensities. The maximum productivity achieved by an air-grown culture was found to be within 10% of the computed maximum productivity, indicating that CO2 was very efficiently removed from the gas stream by the algal culture. Measurements of biomass productivity as a function of cell concentration at different light intensities indicated that both the productivity and efficiency of light utilization were greater at higher light intensities.

40 CFR 1051.105 - What are the exhaust emission standards for off-highway motorcycles?

Code of Federal Regulations, 2010 CFR

2010-07-01

... lights. (B) The absence of a spark arrestor. (C) The absence of manufacturer warranty. (D) Suspension... displacement greater than 70 cc, the minimum useful life is 10,000 kilometers or five years, whichever comes... minimum useful life is 5,000 kilometers or five years, whichever comes first. You must specify a longer...

40 CFR 1051.105 - What are the exhaust emission standards for off-highway motorcycles?

Code of Federal Regulations, 2011 CFR

2011-07-01

... lights. (B) The absence of a spark arrestor. (C) The absence of manufacturer warranty. (D) Suspension... displacement greater than 70 cc, the minimum useful life is 10,000 kilometers or five years, whichever comes... minimum useful life is 5,000 kilometers or five years, whichever comes first. You must specify a longer...

Evaluation of the participation of ferredoxin in oxygen reduction in the photosynthetic electron transport chain of isolated pea thylakoids.

PubMed

Kozuleva, Marina A; Ivanov, Boris N

2010-07-01

The contribution to reduction of oxygen by ferredoxin (Fd) to the overall reduction of oxygen in isolated pea thylakoids was studied in the presence of Fd versus Fd + NADP(+). The overall rate of electron transport was measured using a determination of Photosystem II quantum yield from chlorophyll fluorescence parameters, and the rate of oxidation of Fd was measured from the light-induced redox changes of Fd. At low light intensity, increasing Fd concentration from 5 to 30 microM in the absence of NADP(+) increased the proportion of oxygen reduction by Fd from 25-35 to 40-60% in different experiments. This proportion decreased with increasing light intensity. When NADP(+) was added in the presence of 15 microM Fd, which was optimal for the NADP(+) reduction rate, the participation of Fd in the reduction of oxygen was low, no more than 10%, and it also decreased with increasing light intensity. At high light intensity, the overall oxygen reduction rates in the presence of Fd + NADP(+) and in the presence of Fd alone were comparable. The significance of reduction of dioxygen either by water-soluble Fd or by the membrane-bound carriers of the photosynthetic electron transport chain for redox signaling under different light intensities is discussed.

Inhibition of enteric pathogens using integrated high intensity 405 nm LED on the surface of almonds

USDA-ARS?s Scientific Manuscript database

The disinfecting properties of 405 nm light were investigated against Escherichia coli O157:H7, Salmonella, and their non-pathogenic surrogates inoculated onto the surface of almonds. High intensity monochromatic light was generated from an array of narrow-band 405 nm light emitting diodes (LED). Al...

Diffraction effects in mechanically chopped laser pulses

NASA Astrophysics Data System (ADS)

Gambhir, Samridhi; Singh, Mandip

2018-06-01

A mechanical beam chopper consists of a rotating disc of regularly spaced wide slits which allow light to pass through them. A continuous light beam, after passing through the rotating disc, is switched-on and switched-off periodically, and a series of optical pulses are produced. The intensity of each pulse is expected to rise and fall smoothly with time. However, a careful study has revealed that the edges of mechanically chopped laser light pulses consist of periodic intensity undulations which can be detected with a photo detector. In this paper, it is shown that the intensity undulations in mechanically chopped laser pulses are produced by diffraction of light from the rotating disc, and a detailed explanation is given of the intensity undulations in mechanically chopped laser pulses. An experiment presented in this paper provides an efficient method to capture a one dimensional diffraction profile of light from a straight sharp-edge in the time domain. In addition, the experiment accurately measures wavelengths of three different laser beams from the undulations in mechanically chopped laser light pulses.

Time-of-day effects on voice range profile performance in young, vocally untrained adult females.

PubMed

van Mersbergen, M R; Verdolini, K; Titze, I R

1999-12-01

Time-of-day effects on voice range profile performance were investigated in 20 vocally healthy untrained women between the ages of 18 and 35 years. Each subject produced two complete voice range profiles: one in the morning and one in the evening, about 36 hours apart. The order of morning and evening trials was counterbalanced across subjects. Dependent variables were (1) average minimum and average maximum intensity, (2) Voice range profile area and (3) center of gravity (median semitone pitch and median intensity). In this study, the results failed to reveal any clear evidence of time-of-day effects on voice range profile performance, for any of the dependent variables. However, a reliable interaction of time-of-day and trial order was obtained for average minimum intensity. Investigation of other subject populations, in particular trained vocalists or those with laryngeal lesions, is required for any generalization of the results.

Management of fluorescent lamps in controlled environment chambers

NASA Technical Reports Server (NTRS)

Romer, Mark

1994-01-01

Management of fluorescent lights is recommended to (1) maintain uniformity of light intensity over time and (2) permit reproducibility of lighting conditions during experimental replications. At the McGill Phytotron, the lighting intensity can be controlled to desired level because any individual pair of the 40 lamps in each chamber can be set to be 'on' at any particular time. A lamp canopy service history is maintained for each experiment permitting accurate replication of lighting conditions for subsequent replicate trials.

Ground and space flight experiments of the effects of light, sound and/or temperature on animals

NASA Technical Reports Server (NTRS)

Holley, Daniel C.; Du, Vince; Erikson, Jill; Gott, Jack; Hinchcliffe, Heather; Mele, Gary; Moeller, Karen; Nguyen, Tam; Okumura, Sarah; Robbins, Mark

1994-01-01

Papers on the following topics are presented: (1) rat long term habitability and breeding under low light intensity (5 lux); (2) effects of low light intensity on the rat circadian system; (3) effects of sound/noise on the circadian system of rats; (4) temperature related problems involving the animal enclosure modules (AEM) lighting system; and (5) NASA AEM filter test 92/93 (Rats).

Polarization of the diffuse galactic light.

NASA Technical Reports Server (NTRS)

Sparrow, J. G.; Ney, E. P.

1972-01-01

Polarization measurements made from the satellite OSO-5 show that the polarized intensity in the direction of the Scutum arm of the Galaxy is different in intensity and direction of the polarization from that observed due to the zodiacal light. The observations are consistent with polarized diffuse galactic light superposed on the zodiacal light. The results are interpreted in terms of a model in which the galactic starlight is scattered by interstellar dust.

33 CFR 149.565 - What are the required characteristics and intensity of lights on buoys used to define traffic lanes?

Code of Federal Regulations, 2014 CFR

2014-07-01

... define traffic lanes? (a) The buoy's light color that defines the lateral boundaries of a traffic lane must comply with the buoy color schemes in § 62.25 of this chapter. (b) The buoy light may be fixed or... characteristics and intensity of lights on buoys used to define traffic lanes? 149.565 Section 149.565 Navigation...

33 CFR 149.565 - What are the required characteristics and intensity of lights on buoys used to define traffic lanes?

Code of Federal Regulations, 2011 CFR

2011-07-01

... define traffic lanes? (a) The buoy's light color that defines the lateral boundaries of a traffic lane must comply with the buoy color schemes in § 62.25 of this chapter. (b) The buoy light may be fixed or... characteristics and intensity of lights on buoys used to define traffic lanes? 149.565 Section 149.565 Navigation...

33 CFR 149.565 - What are the required characteristics and intensity of lights on buoys used to define traffic lanes?

Code of Federal Regulations, 2013 CFR

2013-07-01

... define traffic lanes? (a) The buoy's light color that defines the lateral boundaries of a traffic lane must comply with the buoy color schemes in § 62.25 of this chapter. (b) The buoy light may be fixed or... characteristics and intensity of lights on buoys used to define traffic lanes? 149.565 Section 149.565 Navigation...

33 CFR 149.565 - What are the required characteristics and intensity of lights on buoys used to define traffic lanes?

Code of Federal Regulations, 2010 CFR

2010-07-01

... define traffic lanes? (a) The buoy's light color that defines the lateral boundaries of a traffic lane must comply with the buoy color schemes in § 62.25 of this chapter. (b) The buoy light may be fixed or... characteristics and intensity of lights on buoys used to define traffic lanes? 149.565 Section 149.565 Navigation...

33 CFR 149.565 - What are the required characteristics and intensity of lights on buoys used to define traffic lanes?

Code of Federal Regulations, 2012 CFR

2012-07-01

... define traffic lanes? (a) The buoy's light color that defines the lateral boundaries of a traffic lane must comply with the buoy color schemes in § 62.25 of this chapter. (b) The buoy light may be fixed or... characteristics and intensity of lights on buoys used to define traffic lanes? 149.565 Section 149.565 Navigation...

Long lifetime, low intensity light source for use in nighttime viewing of equipment maps and other writings

DOEpatents

Frank, Alan M.; Edwards, William R.

1983-01-01

A long-lifetime light source with sufficiently low intensity to be used for reading a map or other writing at nighttime, while not obscuring the user's normal night vision. This light source includes a diode electrically connected in series with a small power source and a lens properly positioned to focus at least a portion of the light produced by the diode.

Influence of surface light scattering in hydrophobic acrylic intraocular lenses on laser beam transmittance.

PubMed

Shiraya, Tomoyasu; Kato, Satoshi; Minami, Keiichiro; Miyata, Kazunori

2017-02-01

The aim of this study was to experimentally examine the changes in the transmittances of photocoagulation lasers when surface light scattering increases in AcrySof intraocular lenses (IOLs). SA60AT IOLs (Alcon) were acceleratingly aging for 0, 3, 5, and 10 years to simulate surface light scattering, and the surface light-scattering intensities of both IOL surfaces were measured using a Scheimpflug photographer. The powers of laser beams that passed from a laser photocoagulator through the aged IOLs were measured at 532, 577, and 647 nm. Changes in the laser power and transmittance with the years of aging and the intensities of surface light scattering were examined. Although the intensity of surface light scattering increased with the years of aging, the laser power did not change with the years of aging (P > 0.30, Kruskal-Wallis test). There were no significant changes in the laser transmittance with the years of aging or the laser wavelength (P > 0.30 and 0.57, respectively). The intensity of surface light scattering revealed no significant association with the laser transmittance at any wavelength (P > 0.37, liner regression). The increases in the surface light scattering of the AcrySof IOLs would not influence retinal photocoagulation treatments for up to 10 years after implantation.

Accelerometer-Measured Physical Activity and Mortality in Women Aged 63 to 99.

PubMed

LaMonte, Michael J; Buchner, David M; Rillamas-Sun, Eileen; Di, Chongzhi; Evenson, Kelley R; Bellettiere, John; Lewis, Cora E; Lee, I-Min; Tinker, Lesly F; Seguin, Rebecca; Zaslovsky, Oleg; Eaton, Charles B; Stefanick, Marcia L; LaCroix, Andrea Z

2018-05-01

To prospectively examine associations between accelerometer-measured physical activity (PA) and mortality in older women, with an emphasis on light-intensity PA. Prospective cohort study with baseline data collection between March 2012 and April 2014. Women's Health Initiative cohort in the United States. Community-dwelling women aged 63 to 99 (N = 6,382). Minutes per day of usual PA measured using hip-worn triaxial accelerometers, physical functioning measured using the Short Physical Performance Battery, mortality follow-up for a mean 3.1 years through September 2016 (450 deaths). When adjusted for accelerometer wear time, age, race-ethnicity, education, smoking, alcohol, self-rated health, and comorbidities, relative risks (95% confidence intervals) for all-cause mortality across PA tertiles were 1.00 (referent), 0.86 (0.69, 1.08), 0.80 (0.62, 1.03) trend P = .07, for low light; 1.00, 0.57 (0.45, 0.71), 0.47 (0.35, 0.61) trend P < .001, for high light; and, 1.00, 0.63 (0.50, 0.79), 0.42 (0.30, 0.57) trend P < .001, for moderate-to-vigorous PA (MVPA). Associations remained significant for high light-intensity PA and MVPA (P < .001) after further adjustment for physical function. Each 30-min/d increment in light-intensity (low and high combined) PA and MVPA was associated, on average, with multivariable relative risk reductions of 12% and 39%, respectively (P < .01). After further simultaneous adjusting for light intensity and MVPA, the inverse associations remained significant (light-intensity PA: RR = 0.93, 95% CI = 0.89-0.97; MVPA: RR = 0.67, 95% CI = 0.58-0.78). These relative risks did not differ between subgroups for age or race and ethnicity (interaction, P ≥ .14, all). When measured using accelerometers, light-intensity and MVPA are associated with lower mortality in older women. These findings suggest that replacing sedentary time with light-intensity PA is a public health strategy that could benefit an aging society and warrants further investigation. © 2017, Copyright the Authors Journal compilation © 2017, The American Geriatrics Society.

Damage threshold in adult rabbit eyes after scleral cross-linking by riboflavin/blue light application.

PubMed

Iseli, Hans Peter; Körber, Nicole; Karl, Anett; Koch, Christian; Schuldt, Carsten; Penk, Anja; Liu, Qing; Huster, Daniel; Käs, Josef; Reichenbach, Andreas; Wiedemann, Peter; Francke, Mike

2015-10-01

Several scleral cross-linking (SXL) methods were suggested to increase the biomechanical stiffness of scleral tissue and therefore, to inhibit axial eye elongation in progressive myopia. In addition to scleral cross-linking and biomechanical effects caused by riboflavin and light irradiation such a treatment might induce tissue damage, dependent on the light intensity used. Therefore, we characterized the damage threshold and mechanical stiffening effect in rabbit eyes after application of riboflavin combined with various blue light intensities. Adult pigmented and albino rabbits were treated with riboflavin (0.5 %) and varying blue light (450 ± 50 nm) dosages from 18 to 780 J/cm(2) (15 to 650 mW/cm(2) for 20 min). Scleral, choroidal and retinal tissue alterations were detected by means of light microscopy, electron microscopy and immunohistochemistry. Biomechanical changes were measured by shear rheology. Blue light dosages of 480 J/cm(2) (400 mW/cm(2)) and beyond induced pathological changes in ocular tissues; the damage threshold was defined by the light intensities which induced cellular degeneration and/or massive collagen structure changes. At such high dosages, we observed alterations of the collagen structure in scleral tissue, as well as pigment aggregation, internal hemorrhages, and collapsed blood vessels. Additionally, photoreceptor degenerations associated with microglia activation and macroglia cell reactivity in the retina were detected. These pathological alterations were locally restricted to the treated areas. Pigmentation of rabbit eyes did not change the damage threshold after a treatment with riboflavin and blue light but seems to influence the vulnerability for blue light irradiations. Increased biomechanical stiffness of scleral tissue could be achieved with blue light intensities below the characterized damage threshold. We conclude that riboflavin and blue light application increased the biomechanical stiffness of scleral tissue at blue light energy levels below the damage threshold. Therefore, applied blue light intensities below the characterized damage threshold might define a therapeutic blue light tolerance range. Copyright © 2015 Elsevier Ltd. All rights reserved.

Illuminant-adaptive color reproduction for mobile display

NASA Astrophysics Data System (ADS)

Kim, Jong-Man; Park, Kee-Hyon; Kwon, Oh-Seol; Cho, Yang-Ho; Ha, Yeong-Ho

2006-01-01

This paper proposes an illuminant-adaptive reproduction method using light adaptation and flare conditions for a mobile display. Mobile displays, such as PDAs and cellular phones, are viewed under various lighting conditions. In particular, images displayed in daylight are perceived as quite dark due to the light adaptation of the human visual system, as the luminance of a mobile display is considerably lower than that of an outdoor environment. In addition, flare phenomena decrease the color gamut of a mobile display by increasing the luminance of dark areas and de-saturating the chroma. Therefore, this paper presents an enhancement method composed of lightness enhancement and chroma compensation. First, the ambient light intensity is measured using a lux-sensor, then the flare is calculated based on the reflection ratio of the display device and the ambient light intensity. The relative cone response is nonlinear to the input luminance. This is also changed by the ambient light intensity. Thus, to improve the perceived image, the displayed luminance is enhanced by lightness linearization. In this paper, the image's luminance is transformed by linearization of the response to the input luminance according to the ambient light intensity. Next, the displayed image is compensated according to the physically reduced chroma, resulting from flare phenomena. The reduced chroma value is calculated according to the flare for each intensity. The chroma compensation method to maintain the original image's chroma is applied differently for each hue plane, as the flare affects each hue plane differently. At this time, the enhanced chroma also considers the gamut boundary. Based on experimental observations, the outer luminance-intensity generally ranges from 1,000 lux to 30,000 lux. Thus, in the case of an outdoor environment, i.e. greater than 1,000 lux, this study presents a color reproduction method based on an inverse cone response curve and flare condition. Consequently, the proposed algorithm improves the quality of the perceived image adaptive to an outdoor environment.

Variation in light intensity with height and time from subsequent lightning return strokes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jordan, D.M.; Uman, M.A.

1983-08-20

Relative light intensity has been measured photographically as a function of height and time for seven subsequent return strokes in two lightning flashes at ranges of 7.8 and 8.7 km. The film used was Kodak 5474 Shellburst, which has a roughly constant spectral response between 300 and 670 nm. The time resolution was about 1.0 ..mu..s, and the spatial resolution was about 4 m. The observed light signals consisted of a fast rise to peak, followed by a slower decrease to a relatively constant value. The amplitude of the initial light peak decreases exponentially with height with a decay constantmore » of about 0.6 to 0.8 km. The 20% to 80% rise time of the initial light signal is between 1 and 4 ..mu..s near ground and increases by an additional 1 to 2 ..mu..s by the time the return stroke reaches the cloud base, a height between 1 and 2 km. The light intensity 30 ..mu..s after the initial peak is relatively constant with height and has an amplitude that is 15% to 30% of the initial peak near the ground and 50% to 100% of the initial peak at cloud base. The logarithm of the peak light intensity near the ground is roughly proportional to the initial peak electric field intensity, and this in turn implies that the current decrease with height may be much slower than the light decrease. The absolute light intensity has been estimated by integrating the photographic signals from individual channel segments to simulate the calibrated all-sky photoelectric data of Guo and Krider (1982). Using this method, the authors find that the mean peak radiance near the ground is 8.3 x 10/sup 5/ W/m, with a total range from 1.4 x 10/sup 5/ to 3.8 x 10/sup 6/ W/m. 16 references, 11 figures.« less

Interrupting prolonged sitting with brief bouts of light walking or simple resistance activities reduces resting blood pressure and plasma noradrenaline in type 2 diabetes.

PubMed

Dempsey, Paddy C; Sacre, Julian W; Larsen, Robyn N; Straznicky, Nora E; Sethi, Parneet; Cohen, Neale D; Cerin, Ester; Lambert, Gavin W; Owen, Neville; Kingwell, Bronwyn A; Dunstan, David W

2016-12-01

Prolonged sitting is increasingly recognized as a ubiquitous cardiometabolic risk factor, possibly distinct from lack of physical exercise. We examined whether interrupting prolonged sitting with brief bouts of light-intensity activity reduced blood pressure (BP) and plasma noradrenaline in type 2 diabetes (T2D). In a randomized crossover trial, 24 inactive overweight/obese adults with T2D (14 men; mean ± SD; 62 ± 6 years) consumed standardized meals during 3 × 8 h conditions: uninterrupted sitting (SIT); sitting + half-hourly bouts of walking (3.2 km/h for 3-min) (light-intensity walking); and sitting + half-hourly bouts of simple resistance activities for 3 min (SRAs), each separated by 6-14 days washout. Resting seated BP was measured hourly (mean of three recordings, ≥20-min postactivity). Plasma noradrenaline was measured at 30-min intervals for the first hour after meals and hourly thereafter. Compared with SIT, mean resting SBP and DBP were significantly reduced (P < 0.001) for both light-intensity walking (mean ± SEM; -14 ± 1/-8 ± 1 mmHg) and SRA (-16 ± 1/-10 ± 1 mmHg), with a more pronounced effect for SRA (P < 0.05 versus light-intensity walking). Similarly, mean plasma noradrenaline was significantly reduced for both light-intensity walking (-0.3 ± 0.1 nmol/l) and SRA (-0.6 ± 0.1 nmol/l) versus SIT, with SRA lower than light-intensity walking (P < 0.05). Mean resting heart rate was lowered by light-intensity walking (-3 ± 1 bpm; P < 0.05), but not SRA (-1 ± 1 bpm). Interrupting prolonged sitting with brief bouts of light-intensity walking or SRA reduces resting BP and plasma noradrenaline in adults with T2D, with SRA being more effective. Given the ubiquity of sedentary behaviors and poor adherence to structured exercise, this approach may have important implications for BP management in patients with T2D.

Integration of non-Lambertian LED and reflective optical element as efficient street lamp.

PubMed

Pan, Jui-Wen; Tu, Sheng-Han; Sun, Wen-Shing; Wang, Chih-Ming; Chang, Jenq-Yang

2010-06-21

A cost effective, high throughput, and high yield method for the increase of street lamp potency was proposed in this paper. We integrated the imprinting technology and the reflective optical element to obtain a street lamp with high illumination efficiency and without glare effect. The imprinting technique can increase the light extraction efficiency and modulate the intensity distribution in the chip level. The non-Lambertian light source was achieved by using imprinting technique. The compact reflective optical element was added to efficiently suppress the emitting light intensity with small emitting angle for the uniform of illumination intensity and excluded the light with high emitting angle for the prevention of glare. Compared to the conventional street lamp, the novel design has 40% enhancement in illumination intensity, the uniform illumination and the glare effect elimination.

LED Light Characteristics for Surgical Shadowless Lamps and Surgical Loupes

PubMed Central

Kinugawa, Yoshitaka; Nobae, Yuichi; Suzuki, Toshihiro; Tanaka, Yoshiyuki; Toda, Ikuko; Tsubota, Kazuo

2015-01-01

Background: Blue light has more energy than longer wavelength light and can penetrate the eye to reach the retina. When surgeons use magnifying loupes under intensive surgical shadowless lamps for better view of the surgical field, the total luminance is about 200 times brighter than that of typical office lighting. In this study, the effects of 2 types of shadowless lamps were compared. Moreover, the effect of various eyeglasses, which support magnifying loupes, on both the light energy and color rendering was considered. Methods: The light intensity and color rendering were measured on 3 variables: light transmittance, light intensity, and color rendering. Results: Under shadowless lamps, the light energy increased with low-magnification loupes and decreased with high-magnification loupes. Filtering eyeglasses reduced the energy, especially in conditions where the low-magnification loupe was used. The best color-rendering index values were obtained with computer eyeglasses under conventional light-emitting diode shadowless lamps and with no glass and with lightly yellow-tinted lenses under less-blue light-emitting diode. Conclusions: Microsurgeons are exposed to strong lighting throughout their career, and proper color rendering must be considered for easier recognition. Light toxicity and loss of color rendering can be reduced with an appropriate combination of shadowless lamps and colored eyeglasses. PMID:26893987

Feasibility of an appliance energy testing and labeling program for Sri Lanka

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biermayer, Peter; Busch, John; Hakim, Sajid

2000-04-01

A feasibility study evaluated the costs and benefits of establishing a program for testing, labeling and setting minimum efficiency standards for appliances and lighting in Sri Lanka. The feasibility study included: refrigerators, air-conditioners, flourescent lighting (ballasts & CFls), ceiling fans, motors, and televisions.

What to Do if a Compact Fluorescent Light (CFL) Bulb or Fluorescent Tube Light Bulb Breaks: Printable Instructions

EPA Pesticide Factsheets

The broken bulb can continue to release mercury vapor until it is cleaned up and removed. This cleanup guidance represents minimum recommended actions to reduce mercury exposure, and will be updated as more efficient practices are identified.

Nighttime visibility of in-service pavement markings, pavement markers, and guardrail delineation in Alaska (with and without continuous lighting).

DOT National Transportation Integrated Search

2011-03-01

This research determined the visibility of in-service pavement markings along lighted and unlighted highway sections, and compared : visibility of in-service pavement markings to the FHWA proposed minimum retroreflectivity levels for the Alaska Depar...

Influence of light intensity and spectral composition of artificial light at night on melatonin rhythm and mRNA expression of gonadotropins in roach Rutilus rutilus.

PubMed

Brüning, Anika; Hölker, Franz; Franke, Steffen; Kleiner, Wibke; Kloas, Werner

2018-02-01

In this study we investigated the influence of artificial light at night (ALAN) of different intensities (0, 1, 10, 100 lx) and different colours (blue, green, red) on the daily melatonin rhythm and mRNA expression of gonadotropins in roach Rutilus rutilus, a ubiquitous cyprinid, which occur in standing and moderately flowing freshwater habitats of central Europe. Melatonin concentrations were significantly lowered under nocturnal white light already at 1 lx. Low intensity blue, green and red ALAN lowered the melatonin levels significantly in comparison to a dark control. We conclude that ALAN can disturb melatonin rhythms in roach at very low intensities and at different wavelengths and thus light pollution in urban waters has the potential to impact biological rhythms in fish. However, mRNA expression of gonadotropins was not affected by ALAN during the period of the experiments. Thus, suspected implications of ALAN on reproduction of roach could not be substantiated.

Light qualities and dose influence ascorbate pool size in detached oat leaves.

PubMed

Mastropasqua, Linda; Borraccino, Giuseppe; Bianco, Laura; Paciolla, Costantino

2012-02-01

In this work, we studied the mechanism of light influence on AsA pool size in Avena sativa L. under the effects of low intensity light at different wavelengths. Exposure to low intensity light of oat leaf segments incubated in water or in l-galactono-1,4-lactone (GL), resulted in an increase in AsA content compared with the dark control. This increase was due to modulation of l-galactono-1,4-lactone dehydrogenase (GLDH; EC 1.3.2.3) light-dependent activity and was dependent on the size of the endogenous GL pool. Both blue and red light were effective in increasing AsA, and this increase depended on both exposure time and light intensity. Protein biosynthesis, photosynthesis and calcium were involved in controlling the level of light-dependent AsA. We suggest that multiple checkpoints correlated to the presence of light underlie the ascorbate pool size. The presence of a light-activated switch for the maintenance of an adequate AsA level seems to be necessary for the various tasks of scavenging reactive oxygen species, in response to the dark-light cycle which plants experience under natural conditions. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Determination of SBS induced damage limits in large fused silica optics for intense, time varying laser pulses

NASA Astrophysics Data System (ADS)

Kyrazis, D. T.; Weiland, T. L.

1990-10-01

The propagation of intense 3rd harmonic light (0.351 micron) through large optical components of the Nova laser results in fracture damage of the center of the component. This damage is caused by an intense acoustical wave brought to focus in the center by reflecting off the circular edge of the optic. The source of this wave is light generated by transverse stimulated Brillouin scattering (SBS). By taking into account the transient gain characteristics of the SBS, the pulse energy can be correctly predicted that would cause damage for any time variation in intensity in the pump beam, and predict the relative intensity of the Brillouin light. The model is based on the transient behavior of a first order linear system.

Automated Reconstruction of Neural Trees Using Front Re-initialization

PubMed Central

Mukherjee, Amit; Stepanyants, Armen

2013-01-01

This paper proposes a greedy algorithm for automated reconstruction of neural arbors from light microscopy stacks of images. The algorithm is based on the minimum cost path method. While the minimum cost path, obtained using the Fast Marching Method, results in a trace with the least cumulative cost between the start and the end points, it is not sufficient for the reconstruction of neural trees. This is because sections of the minimum cost path can erroneously travel through the image background with undetectable detriment to the cumulative cost. To circumvent this problem we propose an algorithm that grows a neural tree from a specified root by iteratively re-initializing the Fast Marching fronts. The speed image used in the Fast Marching Method is generated by computing the average outward flux of the gradient vector flow field. Each iteration of the algorithm produces a candidate extension by allowing the front to travel a specified distance and then tracking from the farthest point of the front back to the tree. Robust likelihood ratio test is used to evaluate the quality of the candidate extension by comparing voxel intensities along the extension to those in the foreground and the background. The qualified extensions are appended to the current tree, the front is re-initialized, and Fast Marching is continued until the stopping criterion is met. To evaluate the performance of the algorithm we reconstructed 6 stacks of two-photon microscopy images and compared the results to the ground truth reconstructions by using the DIADEM metric. The average comparison score was 0.82 out of 1.0, which is on par with the performance achieved by expert manual tracers. PMID:24386539

Evaluating Physical and Perceptual Responses to Exergames in Chinese Children

PubMed Central

Lau, Patrick W. C.; Liang, Yan; Lau, Erica Y.; Choi, Choung-Rak; Kim, Chang-Gyun; Shin, Myung-Soo

2015-01-01

Purpose: The primary objective of this study was to examine whether exergames could help children reach the recommendations for PA and cardiorespiratory fitness regarding exercise intensity. Differences in perceived physical exertion, EE, VO2, and HR between normal weight (NW) and overweight (OW) children participating in exergames were also examined. Methods: Twenty-one children (age: 10.45 ± 0.88) were assessed for EE, VO2 and HR during rest, in a maximal treadmill test, and while playing different exergames. Ratings of perceived exertion (RPE) (category range: 0 to 10) were also measured during exergaming. Three types of exergames were examined: running, table tennis, and dancing. These games were either performed on a Chinese game console, I-Dong, or another well-developed Western game console (Sony PlayStation 3 or Nintendo Wii). Results: Exergaming resulted in EE (kcal/min) from 2.05–5.14, VO2 (mL/kg/min) from 9.98–25.54, and HR (beats per minute) from 98.05–149.66. Children reported RPE ranging from 1.29 to 5.29. The Chinese exergame, I-Dong Running, was the only game in which children reached a moderate intensity and met the recommended minimum VO2reserve (50%) for cardiorespiratory fitness. Conclusion: Exergames could provide alternative opportunities to enhance children’s physical activity. They could be used as light-to-moderate PA, and with exergames, children can even reach the recommended intensity for developing and maintaining cardiorespiratory fitness. PMID:25872015

A cute and highly contrast-sensitive superposition eye - the diurnal owlfly Libelloides macaronius.

PubMed

Belušič, Gregor; Pirih, Primož; Stavenga, Doekele G

2013-06-01

The owlfly Libelloides macaronius (Insecta: Neuroptera) has large bipartite eyes of the superposition type. The spatial resolution and sensitivity of the photoreceptor array in the dorsofrontal eye part was studied with optical and electrophysiological methods. Using structured illumination microscopy, the interommatidial angle in the central part of the dorsofrontal eye was determined to be Δϕ=1.1 deg. Eye shine measurements with an epi-illumination microscope yielded an effective superposition pupil size of about 300 facets. Intracellular recordings confirmed that all photoreceptors were UV-receptors (λmax=350 nm). The average photoreceptor acceptance angle was 1.8 deg, with a minimum of 1.4 deg. The receptor dynamic range was two log units, and the Hill coefficient of the intensity-response function was n=1.2. The signal-to-noise ratio of the receptor potential was remarkably high and constant across the whole dynamic range (root mean square r.m.s. noise=0.5% Vmax). Quantum bumps could not be observed at any light intensity, indicating low voltage gain. Presumably, the combination of large aperture superposition optics feeding an achromatic array of relatively insensitive receptors with a steep intensity-response function creates a low-noise, high spatial acuity instrument. The sensitivity shift to the UV range reduces the clutter created by clouds within the sky image. These properties of the visual system are optimal for detecting small insect prey as contrasting spots against both clear and cloudy skies.

High light intensity protects photosynthetic apparatus of pea plants against exposure to lead.

PubMed

Romanowska, E; Wróblewska, B; Drozak, A; Siedlecka, M

2006-01-01

The electron transport rates and coupling factor activity in the chloroplasts; adenylate contents, rates of photosynthesis and respiration in the leaves as well as activity of isolated mitochondria were investigated in Pisum sativum L. leaves of plants grown under low or high light intensity and exposed after detachment to 5 mM Pb(NO(3))(2). The presence of Pb(2+) reduced rate of photosynthesis in the leaves from plants grown under the high light (HL) and low light (LL) conditions, whereas the respiration was enhanced in the leaves from HL plants. Mitochondria from Pb(2+) treated HL-leaves oxidized glycine at a higher rate than those isolated from LL leaves. ATP content in the Pb-treated leaves increased to a greater extend in the HL than LL grown plants. Similarly ATP synthase activity increased markedly when chloroplasts isolated from control and Pb-treated leaves of HL and LL grown plants were subjected to high intensity light. The presence of Pb ions was found inhibit ATP synthase activity only in chloroplasts from LL grown plants or those illuminated with low intensity light. Low light intensity during growth also lowered PSI electron transport rates and the Pb(2+) induced changes in photochemical activity of this photosystem were visible only in the chloroplasts isolated from LL grown plants. The activity of PSII was influenced by Pb ions on similar manner in both light conditions. This study demonstrates that leaves from plants grown under HL conditions were more resistant to lead toxicity than those obtained from the LL grown plants. The data indicate that light conditions during growth might play a role in regulation of photosynthetic and respiratory energy conservation in heavy metal stressed plants by increasing the flexibility of the stoichiometry of ATP to ADP production.

Nanomagnetic behavior of fullerene thin films in Earth magnetic field in dark and under polarization light influences.

PubMed

Koruga, Djuro; Nikolić, Aleksandra; Mihajlović, Spomenko; Matija, Lidija

2005-10-01

In this paper magnetic fields intensity of C60 thin films of 60 nm and 100 nm thickness under the influence of polarization lights are presented. Two proton magnetometers were used for measurements. Significant change of magnetic field intensity in range from 2.5 nT to 12.3 nT is identified as a difference of dark and polarization lights of 60 nm and 100 nm thin films thickness, respectively. Specific power density of polarization light was 40 mW/cm2. Based on 200 measurement data average value of difference between magnetic intensity of C60 thin films, with 60 nm and 100 nm thickness, after influence of polarization light, were 3.9 nT and 9.9 nT respectively.

Effect of nitrogen-starvation, light intensity and iron on triacylglyceride/carbohydrate production and fatty acid profile of Neochloris oleoabundans HK-129 by a two-stage process.

PubMed

Sun, Xian; Cao, Yu; Xu, Hui; Liu, Yan; Sun, Jianrui; Qiao, Dairong; Cao, Yi

2014-03-01

Triacylglyceride (TAG) and carbohydrate are potential feedstock for biofuels production. In this study, a two-stage process was applied for enhancing TAG/carbohydrate production in the selected microalgae - Neochloris oleoabundans HK-129. In stage I, effects of nitrogen, light intensity and iron on cell growth were investigated, and the highest biomass productivity of 292.83±5.83mg/L/d was achieved. In stage II, different nitrogen-starvation periods, light intensities and iron concentrations were employed to trigger accumulation of TAG and carbohydrate. The culture under 2-day N-starvation, 200μmol/m(2)/s light intensity and 0.037mM Fe(3+) concentration produced the maximum TAG and carbohydrate productivity of 51.58mg/L/d and 90.70mg/L/d, respectively. Nitrogen starvation period and light intensity had marked effects on TAG/carbohydrate accumulation and fatty acids profile, compared to iron concentration. The microalgal lipid was mainly composed of C16/C18 fatty acids (90.02%), saturated fatty acids (29.82%), and monounsaturated fatty acids (32.67%), which is suitable for biodiesel synthesis. Copyright © 2014 Elsevier Ltd. All rights reserved.

Long lifetime, low intensity light source for use in nighttime viewing of equipment maps and other writings

DOEpatents

Frank, A.M.; Edwards, W.R.

1983-10-11

A long-lifetime light source with sufficiently low intensity to be used for reading a map or other writing at nighttime, while not obscuring the user's normal night vision is disclosed. This light source includes a diode electrically connected in series with a small power source and a lens properly positioned to focus at least a portion of the light produced by the diode. 1 fig.

Long lifetime, low intensity light source for use in nighttime viewing of equipment maps and other writings

DOEpatents

Frank, A.M.; Edwards, W.R.

1982-03-23

A long-lifetime light source is discussed with sufficiently low intensity to be used for reading a map or other writing at nightime, while not obscuring the user's normal night vision. This light source includes a diode electrically connected in series with a small power source and a lens properly positioned to focus at least a portion of the light produced by the diode.

Microparticle analysis system and method

NASA Technical Reports Server (NTRS)

Morrison, Dennis R. (Inventor)

2007-01-01

A device for analyzing microparticles is provided which includes a chamber with an inlet and an outlet for respectively introducing and dispensing a flowing fluid comprising microparticles, a light source for providing light through the chamber and a photometer for measuring the intensity of light transmitted through individual microparticles. The device further includes an imaging system for acquiring images of the fluid. In some cases, the device may be configured to identify and determine a quantity of the microparticles within the fluid. Consequently, a method for identifying and tracking microparticles in motion is contemplated herein. The method involves flowing a fluid comprising microparticles in laminar motion through a chamber, transmitting light through the fluid, measuring the intensities of the light transmitted through the microparticles, imaging the fluid a plurality of times and comparing at least some of the intensities of light between different images of the fluid.

A note on stray light in the Tübingen perimeter.

PubMed Central

Weale, R A; Wheeler, C

1977-01-01

Measurements were made of the relative intensity of light scattered in the neighbourhood of the large and small targets on the Tübingen perimeter. Two target intensities were studied. The scattered light fraction ranged from 0-1 to 25% and its effect was detected more readily by young than by older observers. PMID:843510