Andromeda (M31) optical and infrared disk survey. I. Insights in wide-field near-IR surface photometry

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

Sick, Jonathan; Courteau, Stéphane; Cuillandre, Jean-Charles

We present wide-field near-infrared J and K{sub s} images of the Andromeda Galaxy (M31) taken with WIRCam at the Canada-France-Hawaii Telescope as part of the Andromeda Optical and Infrared Disk Survey. This data set allows simultaneous observations of resolved stars and near-infrared (NIR) surface brightness across M31's entire bulge and disk (within R = 22 kpc), permitting a direct test of the stellar composition of near-infrared light in a nearby galaxy. Here we develop NIR observation and reduction methods to recover a uniform surface brightness map across the 3° × 1° disk of M31 with 27 WIRCam fields. Two sky-targetmore » nodding strategies are tested, and we find that strictly minimizing sky sampling latency cannot improve background subtraction accuracy to better than 2% of the background level due to spatio-temporal variations in the NIR skyglow. We fully describe our WIRCam reduction pipeline and advocate using flats built from night-sky images over a single night, rather than dome flats that do not capture the WIRCam illumination field. Contamination from scattered light and thermal background in sky flats has a negligible effect on the surface brightness shape compared to the stochastic differences in background shape between sky and galaxy disk fields, which are ∼0.3% of the background level. The most dramatic calibration step is the introduction of scalar sky offsets to each image that optimizes surface brightness continuity. Sky offsets reduce the mean surface brightness difference between observation blocks from 1% to <0.1% of the background level, though the absolute background level remains statistically uncertain to 0.15% of the background level. We present our WIRCam reduction pipeline and performance analysis to give specific recommendations for the improvement of NIR wide-field imaging methods.« less

Development of an Ultra-Low Background Liquid Scintillation Counter for Trace Level Analysis

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

Erchinger, Jennifer L.; Orrell, John L.; Aalseth, Craig E.

2015-09-01

Low-level liquid scintillation counting (LSC) has been established as one of the radiation detection techniques useful in elucidating environmental processes and environmental monitoring around nuclear facilities. The Ultra-Low Background Liquid Scintillation Counter (ULB-LSC) under construction in the Shallow Underground Laboratory at Pacific Northwest National Laboratory aims to further reduce the MDAs and/or required sample processing. Through layers of passive shielding in conjunction with an active veto and 30 meters water equivalent overburden, the background reduction is expected to be 10 to 100 times below typical analytic low-background liquid scintillation systems. Simulations have shown an expected background of around 14 countsmore » per day. A novel approach to the light collection will use a coated hollow light guide cut into the inner copper shielding. Demonstration LSC measurements will show low-energy detection, spectral deconvolution, and alpha/beta discrimination capabilities, from trials with standards of tritium, strontium-90, and actinium-227, respectively. An overview of the system design and expected demonstration measurements will emphasize the potential applications of the ULB-LSC in environmental monitoring for treaty verification, reach-back sample analysis, and facility inspections.« less

Object detectability at increased ambient lighting conditions.

PubMed

Pollard, Benjamin J; Chawla, Amarpreet S; Delong, David M; Hashimoto, Noriyuki; Samei, Ehsan

2008-06-01

Under typical dark conditions encountered in diagnostic reading rooms, a reader's pupils will contract and dilate as the visual focus intermittently shifts between the high luminance display and the darker background wall, resulting in increased visual fatigue and the degradation of diagnostic performance. A controlled increase of ambient lighting may, however, reduce the severity of these pupillary adjustments by minimizing the difference between the luminance level to which the eyes adapt while viewing an image (L(adp)) and the luminance level of diffusely reflected light from the area surrounding the display (L(s)). Although ambient lighting in reading rooms has conventionally been kept at a minimum to maintain the perceived contrast of film images, proper Digital Imaging and Communications in Medicine (DICOM) calibration of modern medical-grade liquid crystal displays can compensate for minor lighting increases with very little loss of image contrast. This paper describes two psychophysical studies developed to evaluate and refine optimum reading room ambient lighting conditions through the use of observational tasks intended to simulate real clinical practices. The first study utilized the biologic contrast response of the human visual system to determine a range of representative L(adp) values for typical medical images. Readers identified low contrast horizontal objects in circular foregrounds of uniform luminance (5, 12, 20, and 30 cd/m2) embedded within digitized mammograms. The second study examined the effect of increased ambient lighting on the detection of subtle objects embedded in circular foregrounds of uniform luminance (5, 12, and 35 cd/m2) centered within a constant background of 12 cd/m2 luminance. The images were displayed under a dark room condition (1 lux) and an increased ambient lighting level (50 lux) such that the luminance level of the diffusely reflected light from the background wall was approximately equal to the image L(adp) value of 12 cd/m2. Results from the first study demonstrated that observer true positive and false positive detection rates and true positive detection times were considerably better while viewing foregrounds at 12 and 20 cd/m2 than at the other foreground luminance levels. Results from the second study revealed that under increased room illuminance, the average true positive detection rate improved a statistically significant amount from 39.3% to 55.6% at 5 cd/m2 foreground luminance. Additionally, the true positive rate increased from 46.4% to 56.6% at 35 cd/m2 foreground luminance, and decreased slightly from 90.2% to 87.5% at 12 cd/m2 foreground luminance. False positive rates at all foreground luminance levels remained approximately constant with increased ambient lighting. Furthermore, under increased room illuminance, true positive detection times declined at every foreground luminance level, with the most considerable decrease (approximately 500 ms) at the 5 cd/m2 foreground luminance. The first study suggests that L(adp) of typical mammograms lies between 12 and 20 cd/m2, leading to an optimum reading room illuminance of approximately 50-80 lux. Findings from the second study provide psychophysical evidence that ambient lighting may be increased to a level within this range, potentially improving radiologist comfort, without deleterious effects on diagnostic performance.

Ultra-high contrast retinal display system for single photoreceptor psychophysics

PubMed Central

Domdei, Niklas; Domdei, Lennart; Reiniger, Jenny L.; Linden, Michael; Holz, Frank G.; Roorda, Austin; Harmening, Wolf M.

2017-01-01

Due to the enormous dynamic range of human photoreceptors in response to light, studying their visual function in the intact retina challenges the stimulation hardware, specifically with regard to the displayable luminance contrast. The adaptive optics scanning laser ophthalmoscope (AOSLO) is an optical platform that focuses light to extremely small retinal extents, approaching the size of single photoreceptor cells. However, the current light modulation techniques produce spurious visible backgrounds which fundamentally limit experimental options. To remove unwanted background light and to improve contrast for high dynamic range visual stimulation in an AOSLO, we cascaded two commercial fiber-coupled acousto-optic modulators (AOMs) and measured their combined optical contrast. By compensating for zero-point differences in the individual AOMs, we demonstrate a multiplicative extinction ratio in the cascade that was in accordance with the extinction ratios of both single AOMs. When latency differences in the AOM response functions were individually corrected, single switch events as short as 50 ns with radiant power contrasts up to 1:1010 were achieved. This is the highest visual contrast reported for any display system so far. We show psychophysically that this contrast ratio is sufficient to stimulate single foveal photoreceptor cells with small and bright enough visible targets that do not contain a detectable background. Background-free stimulation will enable photoreceptor testing with custom adaptation lights. Furthermore, a larger dynamic range in displayable light levels can drive photoreceptor responses in cones as well as in rods. PMID:29359094

Optimised mounting conditions for poly (ether sulfone) in radiation detection.

PubMed

Nakamura, Hidehito; Shirakawa, Yoshiyuki; Sato, Nobuhiro; Yamada, Tatsuya; Kitamura, Hisashi; Takahashi, Sentaro

2014-09-01

Poly (ether sulfone) (PES) is a candidate for use as a scintillation material in radiation detection. Its characteristics, such as its emission spectrum and its effective refractive index (based on the emission spectrum), directly affect the propagation of light generated to external photodetectors. It is also important to examine the presence of background radiation sources in manufactured PES. Here, we optimise the optical coupling and surface treatment of the PES, and characterise its background. Optical grease was used to enhance the optical coupling between the PES and the photodetector; absorption by the grease of short-wavelength light emitted from PES was negligible. Diffuse reflection induced by surface roughening increased the light yield for PES, despite the high effective refractive index. Background radiation derived from the PES sample and its impurities was negligible above the ambient, natural level. Overall, these results serve to optimise the mounting conditions for PES in radiation detection. Copyright © 2014 Elsevier Ltd. All rights reserved.

Interaction and developmental activation of two neuroendocrine systems that regulate light-mediated skin pigmentation.

PubMed

Bertolesi, Gabriel E; Song, Yi N; Atkinson-Leadbeater, Karen; Yang, Jung-Lynn J; McFarlane, Sarah

2017-07-01

Lower vertebrates use rapid light-regulated changes in skin colour for camouflage (background adaptation) or during circadian variation in irradiance levels. Two neuroendocrine systems, the eye/alpha-melanocyte-stimulating hormone (α-MSH) and the pineal complex/melatonin circuits, regulate the process through their respective dispersion and aggregation of pigment granules (melanosomes) in skin melanophores. During development, Xenopus laevis tadpoles raised on a black background or in the dark perceive less light sensed by the eye and darken in response to increased α-MSH secretion. As embryogenesis proceeds, the pineal complex/melatonin circuit becomes the dominant regulator in the dark and induces lightening of the skin of larvae. The eye/α-MSH circuit continues to mediate darkening of embryos on a black background, but we propose the circuit is shut down in complete darkness in part by melatonin acting on receptors expressed by pituitary cells to inhibit the expression of pomc, the precursor of α-MSH. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

A photoelastic-modulator-based motional Stark effect polarimeter for ITER that is insensitive to polarized broadband background reflections.

PubMed

Thorman, A; Michael, C; De Bock, M; Howard, J

2016-07-01

A motional Stark effect polarimeter insensitive to polarized broadband light is proposed. Partially polarized background light is anticipated to be a significant source of systematic error for the ITER polarimeter. The proposed polarimeter is based on the standard dual photoelastic modulator approach, but with the introduction of a birefringent delay plate, it generates a sinusoidal spectral filter instead of the usual narrowband filter. The period of the filter is chosen to match the spacing of the orthogonally polarized Stark effect components, thereby increasing the effective signal level, but resulting in the destructive interference of the broadband polarized light. The theoretical response of the system to an ITER like spectrum is calculated and the broadband polarization tolerance is verified experimentally.

Cosmic ray oriented performance studies for the JEM-EUSO first level trigger

NASA Astrophysics Data System (ADS)

Abdellaoui, G.; Abe, S.; Acheli, A.; Adams, J. H.; Ahmad, S.; Ahriche, A.; Albert, J.-N.; Allard, D.; Alonso, G.; Anchordoqui, L.; Andreev, V.; Anzalone, A.; Aouimeur, W.; Arai, Y.; Arsene, N.; Asano, K.; Attallah, R.; Attoui, H.; Ave Pernas, M.; Bacholle, S.; Bakiri, M.; Baragatti, P.; Barrillon, P.; Bartocci, S.; Batsch, T.; Bayer, J.; Bechini, R.; Belenguer, T.; Bellotti, R.; Belov, A.; Belov, K.; Benadda, B.; Benmessai, K.; Berlind, A. A.; Bertaina, M.; Biermann, P. L.; Biktemerova, S.; Bisconti, F.; Blanc, N.; Błȩcki, J.; Blin-Bondil, S.; Bobik, P.; Bogomilov, M.; Bonamente, M.; Boudaoud, R.; Bozzo, E.; Briggs, M. S.; Bruno, A.; Caballero, K. S.; Cafagna, F.; Campana, D.; Capdevielle, J.-N.; Capel, F.; Caramete, A.; Caramete, L.; Carlson, P.; Caruso, R.; Casolino, M.; Cassardo, C.; Castellina, A.; Castellini, G.; Catalano, C.; Catalano, O.; Cellino, A.; Chikawa, M.; Chiritoi, G.; Christl, M. J.; Connaughton, V.; Conti, L.; Contino, G.; Cordero, G.; Cotto, G.; Crawford, H. J.; Cremonini, R.; Csorna, S.; Dagoret-Campagne, S.; De Donato, C.; de la Taille, C.; De Santis, C.; del Peral, L.; Di Martino, M.; Djemil, T.; Djenas, S. A.; Dulucq, F.; Dupieux, M.; Dutan, I.; Ebersoldt, A.; Ebisuzaki, T.; Engel, R.; Eser, J.; Fang, K.; Fenu, F.; Fernández-González, S.; Fernández-Soriano, J.; Ferrarese, S.; Finco, D.; Flamini, M.; Fornaro, C.; Forza, R.; Fouka, M.; Franceschi, A.; Franchini, S.; Fuglesang, C.; Fujimoto, J.; Fukushima, M.; Galeotti, P.; García-Ortega, E.; Garipov, G.; Gascón, E.; Geary, J.; Gelmini, G.; Genci, J.; Giraudo, G.; Gonchar, M.; González Alvarado, C.; Gorodetzky, P.; Guardone, N.; Guarino, F.; Guehaz, R.; Guzmán, A.; Hachisu, Y.; Haiduc, M.; Harlov, B.; Haungs, A.; Hernández Carretero, J.; Hidber, W.; Higashide, K.; Ikeda, D.; Ikeda, H.; Inoue, N.; Inoue, S.; Insolia, A.; Isgrò, F.; Itow, Y.; Jammer, T.; Joven, E.; Judd, E. G.; Jung, A.; Jochum, J.; Kajino, F.; Kajino, T.; Kalli, S.; Kaneko, I.; Kang, D.; Kanouni, F.; Karadzhov, Y.; Karczmarczyk, J.; Karus, M.; Katahira, K.; Kawai, K.; Kawasaki, Y.; Kedadra, A.; Khales, H.; Khrenov, B. A.; Kim, Jeong-Sook; Kim, Soon-Wook; Kim, Sug-Whan; Kleifges, M.; Klimov, P. A.; Kolev, D.; Kreykenbohm, I.; Kudela, K.; Kurihara, Y.; Kusenko, A.; Kuznetsov, E.; Lacombe, M.; Lachaud, C.; Lahmar, H.; Lakhdari, F.; Larsson, O.; Lee, J.; Licandro, J.; Lim, H.; López Campano, L.; Maccarone, M. C.; Mackovjak, S.; Mahdi, M.; Manfrin, M.; Maravilla, D.; Marcelli, L.; Marcos, J. L.; Marini, A.; Martens, K.; Martín, Y.; Martinez, O.; Masciantonio, G.; Mase, K.; Matev, R.; Matthews, J. N.; Mebarki, N.; Medina-Tanco, G.; Mehrad, L.; Mendoza, M. A.; Merino, A.; Mernik, T.; Meseguer, J.; Messaoud, S.; Micu, O.; Mignone, M.; Mimouni, J.; Miyamoto, H.; Miyazaki, Y.; Mizumoto, Y.; Modestino, G.; Monaco, A.; Monnier-Ragaigne, D.; Morales de los Ríos, J. A.; Moretto, C.; Morozenko, V. S.; Mot, B.; Murakami, T.; Nadji, B.; Nagano, M.; Nagata, M.; Nagataki, S.; Nakamura, T.; Napolitano, T.; Naumov, D.; Nava, R.; Neronov, A.; Nomoto, K.; Nonaka, T.; Ogawa, T.; Ogio, S.; Ohmori, H.; Olinto, A. V.; Orleański, P.; Osteria, G.; Painter, W.; Panasyuk, M. I.; Panico, B.; Parizot, E.; Park, I. H.; Park, H. W.; Pastircak, B.; Patzak, T.; Paul, T.; Pennypacker, C.; Pérez-Grande, I.; Perfetto, F.; Peter, T.; Picozza, P.; Pierog, T.; Pindado, S.; Piotrowski, L. W.; Piraino, S.; Placidi, L.; Plebaniak, Z.; Pliego, S.; Pollini, A.; Popescu, E. M.; Prat, P.; Prévôt, G.; Prieto, H.; Putis, M.; Rabanal, J.; Radu, A. A.; Rahmani, M.; Reardon, P.; Reyes, M.; Rezazadeh, M.; Ricci, M.; Rodríguez Frías, M. D.; Ronga, F.; Roth, M.; Rothkaehl, H.; Roudil, G.; Rusinov, I.; Rybczyński, M.; Sabau, M. D.; Sáez Cano, G.; Sagawa, H.; Sahnoune, Z.; Saito, A.; Sakaki, N.; Sakata, M.; Salazar, H.; Sanchez, J. C.; Sánchez, J. L.; Santangelo, A.; Santiago Crúz, L.; Sanz-Andrés, A.; Sanz Palomino, M.; Saprykin, O.; Sarazin, F.; Sato, H.; Sato, M.; Schanz, T.; Schieler, H.; Scotti, V.; Segreto, A.; Selmane, S.; Semikoz, D.; Serra, M.; Sharakin, S.; Shibata, T.; Shimizu, H. M.; Shinozaki, K.; Shirahama, T.; Siemieniec-Oziȩbło, G.; Sledd, J.; Słomińska, K.; Sobey, A.; Stan, I.; Sugiyama, T.; Supanitsky, D.; Suzuki, M.; Szabelska, B.; Szabelski, J.; Tahi, H.; Tajima, F.; Tajima, N.; Tajima, T.; Takahashi, Y.; Takami, H.; Takeda, M.; Takizawa, Y.; Talai, M. C.; Tenzer, C.; Tibolla, O.; Tkachev, L.; Tokuno, H.; Tomida, T.; Tone, N.; Toscano, S.; Traïche, M.; Tsenov, R.; Tsunesada, Y.; Tsuno, K.; Tymieniecka, T.; Uchihori, Y.; Unger, M.; Vaduvescu, O.; Valdés-Galicia, J. F.; Vallania, P.; Vankova, G.; Vigorito, C.; Villaseñor, L.; Vlcek, B.; von Ballmoos, P.; Vrabel, M.; Wada, S.; Watanabe, J.; Watanabe, S.; Watts, J.; Weber, M.; Weigand Muñoz, R.; Weindl, A.; Weiler, T. J.; Wibig, T.; Wiencke, L.; Wille, M.; Wilms, J.; Włodarczyk, Z.; Yamamoto, T.; Yamamoto, Y.; Yang, J.; Yano, H.; Yashin, I. V.; Yonetoku, D.; Yoshida, S.; Young, R.; Zgura, I. S.; Zotov, M. Yu.; Zuccaro Marchi, A.

2017-09-01

JEM-EUSO is a space mission designed to investigate Ultra-High Energy Cosmic Rays and Neutrinos (E > 5 ṡ 1019 eV) from the International Space Station (ISS). Looking down from above its wide angle telescope is able to observe their air showers and collect such data from a very wide area. Highly specific trigger algorithms are needed to drastically reduce the data load in the presence of both atmospheric and human activity related background light, yet retain the rare cosmic ray events recorded in the telescope. We report the performance in offline testing of the first level trigger algorithm on data from JEM-EUSO prototypes and laboratory measurements observing different light sources: data taken during a high altitude balloon flight over Canada, laser pulses observed from the ground traversing the real atmosphere, and model landscapes reproducing realistic aspect ratios and light conditions as would be seen from the ISS itself. The first level trigger logic successfully kept the trigger rate within the permissible bounds when challenged with artificially produced as well as naturally encountered night sky background fluctuations and while retaining events with general air-shower characteristics.

FIN219/JAR1 and cryptochrome1 antagonize each other to modulate photomorphogenesis under blue light in Arabidopsis

PubMed Central

2018-01-01

Plant development is affected by the integration of light and phytohormones, including jasmonates (JAs). To address the molecular mechanisms of possible interactions between blue light and JA signaling in Arabidopsis thaliana, we used molecular and transgenic approaches to understand the regulatory relationships between FAR-RED INSENSITIVE 219 (FIN219)/JASMONATE RESISTANT1 (JAR1) and the blue-light photoreceptor cryptochrome1 (CRY1). FIN219 overexpression in the wild type resulted in a short-hypocotyl phenotype under blue light. However, FIN219 overexpression in cry1, cry2 and cry1cry2 double mutant backgrounds resulted in phenotypes similar to their respective mutant backgrounds, which suggests that FIN219 function may require blue light photoreceptors. Intriguingly, FIN219 overexpression in transgenic plants harboring ectopic expression of the C terminus of CRY1 (GUS-CCT1), which exhibits a hypersensitive short-hypocotyl phenotype in all light conditions including darkness, led to a rescued phenotype under all light conditions except red light. Further expression studies showed mutual suppression between FIN219 and CRY1 under blue light. Strikingly, FIN219 overexpression in GUS-CCT1 transgenic lines (FIN219-OE/GUS-CCT1) abolished GUS-CCT1 fusion protein under blue light, whereas GUS-CCT1 fusion protein was stable in the fin219-2 mutant background (fin219-2/GUS-CCT1). Moreover, FIN219 strongly interacted with COP1 under blue light, and methyl JA (MeJA) treatment enhanced the interaction between FIN219 and GUS-CCT1 under blue light. Furthermore, FIN219 level affected GUS-CCT1 seedling responses such as anthocyanin accumulation and bacterial resistance under various light conditions and MeJA treatment. Thus, FIN219/JAR1 and CRY1 antagonize each other to modulate photomorphogenic development of seedlings and stress responses in Arabidopsis. PMID:29561841

FIN219/JAR1 and cryptochrome1 antagonize each other to modulate photomorphogenesis under blue light in Arabidopsis.

PubMed

Chen, Huai-Ju; Fu, Tsu-Yu; Yang, Shao-Li; Hsieh, Hsu-Liang

2018-03-01

Plant development is affected by the integration of light and phytohormones, including jasmonates (JAs). To address the molecular mechanisms of possible interactions between blue light and JA signaling in Arabidopsis thaliana, we used molecular and transgenic approaches to understand the regulatory relationships between FAR-RED INSENSITIVE 219 (FIN219)/JASMONATE RESISTANT1 (JAR1) and the blue-light photoreceptor cryptochrome1 (CRY1). FIN219 overexpression in the wild type resulted in a short-hypocotyl phenotype under blue light. However, FIN219 overexpression in cry1, cry2 and cry1cry2 double mutant backgrounds resulted in phenotypes similar to their respective mutant backgrounds, which suggests that FIN219 function may require blue light photoreceptors. Intriguingly, FIN219 overexpression in transgenic plants harboring ectopic expression of the C terminus of CRY1 (GUS-CCT1), which exhibits a hypersensitive short-hypocotyl phenotype in all light conditions including darkness, led to a rescued phenotype under all light conditions except red light. Further expression studies showed mutual suppression between FIN219 and CRY1 under blue light. Strikingly, FIN219 overexpression in GUS-CCT1 transgenic lines (FIN219-OE/GUS-CCT1) abolished GUS-CCT1 fusion protein under blue light, whereas GUS-CCT1 fusion protein was stable in the fin219-2 mutant background (fin219-2/GUS-CCT1). Moreover, FIN219 strongly interacted with COP1 under blue light, and methyl JA (MeJA) treatment enhanced the interaction between FIN219 and GUS-CCT1 under blue light. Furthermore, FIN219 level affected GUS-CCT1 seedling responses such as anthocyanin accumulation and bacterial resistance under various light conditions and MeJA treatment. Thus, FIN219/JAR1 and CRY1 antagonize each other to modulate photomorphogenic development of seedlings and stress responses in Arabidopsis.

Effects of guidelines implementation in a surgical intensive care unit to control nighttime light and noise levels.

PubMed

Walder, B; Francioli, D; Meyer, J J; Lançon, M; Romand, J A

2000-07-01

Because of around-the-clock activities, environmental noise and light are among the many causes of sleep disturbance in an intensive care unit (ICU). The implementation of guidelines may potentially change behavior rules and improve sleep quality. A prospective interventional study, observing the effects of simple nighttime guidelines on light and noise levels in an ICU. A modern surgical ICU, subdivided into six identical three-bed rooms. Critically ill adult patients. Between two observation periods, five guidelines were implemented to decrease both light and noise during the night shift in the patient's room. Light levels and noise levels were obtained using a luxmeter and a sound level meter [A-weighted decibels (dB) scale] and were monitored continuously from 11 pm to 5 am both before (period P1) and after (period P2) the implementation of guidelines. Similar patient's gravity and nursing workload scores were observed between P1 and P2. A low mean (<5 Lux) and maximal light level were measured during both P1 and P2. The implementation of guidelines lowered mean light disturbance intensity with a greater variability of light during P2. All noise levels were high and corresponded more to a quiet office for noise level equivalents and to a busy restaurant for peak noise levels during both P1 and P2. Guidelines decreased the noise level equivalent (P1, 51.3 dB; P2, 48.3 dB), peak noise level (P1, 74.9 dB; P2, 70.8 dB), and the number of acoustic identified alarms (P1, 22.1 dB; P2, 15.8 dB) during P2. The night light levels were low during both periods, and lowering the light levels induced a greater variation of light, which may impair sleep quality. All measured noise levels were high during both periods, which could contribute to sleep disturbance, and the implementation of guidelines significantly lowers some important noise levels. The background noise level was unchanged.

Effects of oxytocin on background anxiety in rats with high or low baseline startle

PubMed Central

Ayers, Luke; Agostini, Andrew; Schulkin, Jay; Rosen, Jeffrey B.

2016-01-01

Rationale Oxytocin has antianxiety properties in humans and rodents. However, the antianxiety effects have been variable. Objectives To reduce variability and strengthen to the antianxiety effect of oxytocin in fear-potentiated startle, two experiments were performed. First, different amounts of light-shock pairings were given to determine the optimal levels of cue-specific fear conditioning and non-predictable startle (background anxiety). Second, the antianxiety effects of oxytocin were examined in rats with high and low pre-fear conditioning baseline startle to determine if oxytocin differentially affects high and low trait anxiety rats. Methods Baseline pre-fear conditioning startle responses were first measured. Rats then received 1, 5 or 10 light-shock pairings. Fear-potentiated startle was then tested with two trial types: light-cued startle and non-cued startle trials. In the second experiment, rats fear conditioned with 10 light-shock pairings were administered either saline or oxytocin before a fear-potentiated startle test. Rats were categorized as low or high startlers by their pre-fear conditioning startle amplitude. Results Ten shock-pairings produced the largest non-cued startle responses (background anxiety), without increasing cue-specific fear-potentiated startle compared to 1 and 5 light-shock pairings. Cue-specific fear-potentiated startle was unaffected by oxytocin. Oxytocin reduced background anxiety only in rats with low pre-fear startle responses. Conclusions Oxytocin has population selective antianxiety effects on non-cued unpredictable threat, but only in rats with low pre-fear baseline startle responses. The low startle responses are reminiscent of humans with low startle responses and high trait anxiety. PMID:27004789

Regulation of BolA abundance mediates morphogenesis in Fremyella diplosiphon

DOE PAGES

Singh, Shailendra P.; Montgomery, Beronda L.

2015-11-05

Filamentous cyanobacterium Fremyella diplosiphon is known to alter its pigmentation and morphology during complementary chromatic acclimation (CCA) to efficiently harvest available radiant energy for photosynthesis. F. diplosiphon cells are rectangular and filaments are longer under green light (GL), whereas smaller, spherical cells and short filaments are prevalent under red light (RL). Light regulation of bolA morphogene expression is correlated with photoregulation of cellular morphology in F. diplosiphon. Here, we investigate a role for quantitative regulation of cellular BolA protein levels in morphology determination. Overexpression of bolA in WT was associated with induction of RL-characteristic spherical morphology even when cultures weremore » grown under GL. Overexpression of bolA in a ΔrcaE background, which lacks cyanobacteriochrome photosensor RcaE and accumulates lower levels of BolA than WT, partially reverted the cellular morphology of the strain to a WT-like state. Overexpression of BolA in WT and ΔrcaE backgrounds was associated with decreased cellular reactive oxygen species (ROS) levels and an increase in filament length under both GL and RL. Morphological defects and high ROS levels commonly observed in ΔrcaE could, thus, be in part due to low accumulation of BolA. Together, these findings support an emerging model for RcaE-dependent photoregulation of BolA in controlling the cellular morphology of F. diplosiphon during CCA.« less

White Light–Emitting Diodes (LEDs) at Domestic Lighting Levels and Retinal Injury in a Rat Model

PubMed Central

Shang, Yu-Man; Wang, Gen-Shuh; Sliney, David; Lee, Li-Ling

2013-01-01

Background: Light-emitting diodes (LEDs) deliver higher levels of blue light to the retina than do conventional domestic light sources. Chronic exposure to high-intensity light (2,000–10,000 lux) has previously been found to result in light-induced retinal injury, but chronic exposure to relatively low-intensity (750 lux) light has not been previously assessed with LEDs in a rodent model. Objective: We examined LED-induced retinal neuronal cell damage in the Sprague-Dawley rat using functional, histological, and biochemical measurements. Methods: We used blue LEDs (460 nm) and full-spectrum white LEDs, coupled with matching compact fluorescent lights, for exposures. Pathological examinations included electroretinogram, hematoxylin and eosin (H&E) staining, immunohistochemistry (IHC), and transmission electron microscopy (TEM). We also measured free radical production in the retina to determine the oxidative stress level. Results: H&E staining and TEM revealed apoptosis and necrosis of photoreceptors, which indicated blue-light induced photochemical injury of the retina. Free radical production in the retina was increased in LED-exposed groups. IHC staining demonstrated that oxidative stress was associated with retinal injury. Although we found serious retinal light injury in LED groups, the compact fluorescent lamp (CFL) groups showed moderate to mild injury. Conclusion: Our results raise questions about adverse effects on the retina from chronic exposure to LED light compared with other light sources that have less blue light. Thus, we suggest a precautionary approach with regard to the use of blue-rich “white” LEDs for general lighting. Citation: Shang YM, Wang GS, Sliney D, Yang CH, Lee LL. 2014. White light–emitting diodes (LEDs) at domestic lighting levels and retinal injury in a rat model. Environ Health Perspect 122:269–276; http://dx.doi.org/10.1289/ehp.1307294 PMID:24362357

Light Regulation of Brassinosteroid Signaling Components: Checking Regulation of Protein Stability in Darkness.

PubMed

Corvalán, Claudia; Choe, Sunghwa

2017-01-01

Environmental conditions can affect stability of proteins at transcriptional or posttranscriptional levels to modulate their functions. Here we describe a method to observe changes in protein stability under different light conditions. In brief, Arabidopsis thaliana seedlings were maintained under various light regimes from continuous light to total darkness or transitions from light to dark, whereafter total protein was extracted from plants. Proteins were measured and resolved on sodium dodecyl sulfate-polyacrylamide gels and transferred to polyvinylidene difluoride membranes. Blots were incubated with the corresponding antibodies for the visualization of protein bands. The protocol described has been successfully applied in wild-type, different transgenic, and mutant background plants to study how light alone or in combination with other factors influences protein stability.

Transcranial Red and Near Infrared Light Transmission in a Cadaveric Model

PubMed Central

Jagdeo, Jared R.; Adams, Lauren E.; Brody, Neil I.; Siegel, Daniel M.

2012-01-01

Background and Objective Low level light therapy has garnered significant interest within the past decade. The exact molecular mechanisms of how red and near infrared light result in physiologic modulation are not fully understood. Heme moieties and copper within cells are red and near infrared light photoreceptors that induce the mitochondrial respiratory chain component cytochrome C oxidase, resulting in a cascade linked to cytoprotection and cellular metabolism. The copper centers in cytochrome C oxidase have a broad absorption range that peaks around 830 nm. Several in vitro and in vivo animal and human models exist that have demonstrated the benefits of red light and near infrared light for various conditions. Clinical applications for low level light therapy are varied. One study in particular demonstrated improved durable functional outcomes status post-stroke in patients treated with near infrared low level light therapy compared to sham treatment [1]. Despite previous data suggesting the beneficial effect in treating multiple conditions, including stroke, with low level light therapy, limited data exists that measures transmission in a human model. Study Design/Materials and Methods To investigate this idea, we measured the transmission of near infrared light energy, using red light for purposes of comparison, through intact cadaver soft tissue, skull bones, and brain using a commercially available LED device at 830 nm and 633 nm. Results Our results demonstrate that near infrared measurably penetrates soft tissue, bone and brain parenchyma in the formalin preserved cadaveric model, in comparison to negligible red light transmission in the same conditions. Conclusion These findings indicate that near infrared light can penetrate formalin fixed soft tissue, bone and brain and implicate that benefits observed in clinical studies are potentially related to direct action of near infrared light on neural tissue. PMID:23077622

40 CFR 82.110 - Form of label bearing warning statement.

Code of Federal Regulations, 2012 CFR

2012-07-01

... contrast are: black letters on a dark blue or dark green background, dark red letters on a light red background, light red letters on a reflective silver background, and white letters on a light gray or tan...

40 CFR 82.110 - Form of label bearing warning statement.

Code of Federal Regulations, 2013 CFR

2013-07-01

... contrast are: black letters on a dark blue or dark green background, dark red letters on a light red background, light red letters on a reflective silver background, and white letters on a light gray or tan...

Studying the Light Pollution around Urban Observatories: Columbus State University’s WestRock Observatory

NASA Astrophysics Data System (ADS)

O'Keeffe, Brendon Andrew; Johnson, Michael

2017-01-01

Light pollution plays an ever increasing role in the operations of observatories across the world. This is especially true in urban environments like Columbus, GA, where Columbus State University’s WestRock Observatory is located. Light pollution’s effects on an observatory include high background levels, which results in a lower signal to noise ratio. Overall, this will limit what the telescope can detect, and therefore limit the capabilities of the observatory as a whole.Light pollution has been mapped in Columbus before using VIIRS DNB composites. However, this approach did not provide the detailed resolution required to narrow down the problem areas around the vicinity of the observatory. The purpose of this study is to assess the current state of light pollution surrounding the WestRock observatory by measuring and mapping the brightness of the sky due to light pollution using light meters and geographic information system (GIS) software.Compared to VIIRS data this study allows for an improved spatial resolution and a direct measurement of the sky background. This assessment will enable future studies to compare their results to the baseline established here, ensuring that any changes to the way the outdoors are illuminated and their effects can be accurately measured, and counterbalanced.

Reduction of background clutter in structured lighting systems

DOEpatents

Carlson, Jeffrey J.; Giles, Michael K.; Padilla, Denise D.; Davidson, Jr., Patrick A.; Novick, David K.; Wilson, Christopher W.

2010-06-22

Methods for segmenting the reflected light of an illumination source having a characteristic wavelength from background illumination (i.e. clutter) in structured lighting systems can comprise pulsing the light source used to illuminate a scene, pulsing the light source synchronously with the opening of a shutter in an imaging device, estimating the contribution of background clutter by interpolation of images of the scene collected at multiple spectral bands not including the characteristic wavelength and subtracting the estimated background contribution from an image of the scene comprising the wavelength of the light source and, placing a polarizing filter between the imaging device and the scene, where the illumination source can be polarized in the same orientation as the polarizing filter. Apparatus for segmenting the light of an illumination source from background illumination can comprise an illuminator, an image receiver for receiving images of multiple spectral bands, a processor for calculations and interpolations, and a polarizing filter.

641 N Michigan, September 2011, Lindsay Light Radiological Survey

EPA Pesticide Factsheets

The unshielded field gamma measurements within the spoil matehals generated during the drilling processdid not exceed the respective threshold values previously stated and ranged from background levels of 4,000cpm to a maximum of about 8,000 cpm.

The Quantized Geometry of Visual Space: The Coherent Computation of Depth, Form, and Lightness. Revised Version.

DTIC Science & Technology

1982-08-01

of sensitivity with background luminance, and the finitE capacity of visual short term memory are discussed in terms of a small set of ...binocular rivalry, reflectance rivalry, Fechner’s paradox, decrease of threshold contrast with increased number of cycles in a grating pattern, hysteresis...adaptation level tuning, Weber law modulation, shift of sensitivity with background luminance, and the finite capacity of visual

Low-Level Light Stimulates Excisional Wound Healing in Mice

PubMed Central

Demidova-Rice, Tatiana N.; Salomatina, Elena V.; Yaroslavsky, Anna N.; Herman, Ira M.; Hamblin, Michael R.

2010-01-01

Background Low levels of laser or non-coherent light, termed low-level light therapy (LLLT) have been reported to accelerate some phases of wound healing, but its clinical use remains controversial. Methods A full thickness dorsal excisional wound in mice was treated with a single exposure to light of various wavelengths and fluences 30 minutes after wounding. Wound areas were measured until complete healing and immunofluorescence staining of tissue samples was carried out. Results Wound healing was significantly stimulated in BALB/c and SKH1 hairless mice but not in C57BL/6 mice. Illuminated wounds started to contract while control wounds initially expanded for the first 24 hours. We found a biphasic dose–response curve for fluence of 635-nm light with a maximum positive effect at 2 J/cm2. Eight hundred twenty nanometer was found to be the best wavelength tested compared to 635, 670, and 720 nm. We found no difference between non-coherent 635 ± 15-nm light from a lamp and coherent 633-nm light from a He/Ne laser. LLLT increased the number of α-smooth muscle actin (SMA)-positive cells at the wound edge. Conclusion LLLT stimulates wound contraction in susceptible mouse strains but the mechanism remains uncertain. PMID:17960752

Quantitative Assessment of Fat Levels in Caenorhabditis elegans Using Dark Field Microscopy

PubMed Central

Fouad, Anthony D.; Pu, Shelley H.; Teng, Shelly; Mark, Julian R.; Fu, Moyu; Zhang, Kevin; Huang, Jonathan; Raizen, David M.; Fang-Yen, Christopher

2017-01-01

The roundworm Caenorhabditis elegans is widely used as a model for studying conserved pathways for fat storage, aging, and metabolism. The most broadly used methods for imaging fat in C. elegans require fixing and staining the animal. Here, we show that dark field images acquired through an ordinary light microscope can be used to estimate fat levels in worms. We define a metric based on the amount of light scattered per area, and show that this light scattering metric is strongly correlated with worm fat levels as measured by Oil Red O (ORO) staining across a wide variety of genetic backgrounds and feeding conditions. Dark field imaging requires no exogenous agents or chemical fixation, making it compatible with live worm imaging. Using our method, we track fat storage with high temporal resolution in developing larvae, and show that fat storage in the intestine increases in at least one burst during development. PMID:28404661

A Glossy Simultaneous Contrast: Conjoint Measurements of Gloss and Lightness

PubMed Central

Mamassian, Pascal

2017-01-01

Interactions between the albedo and the gloss on a surface are commonplace. Darker surfaces are perceived glossier (contrast gloss) than lighter surfaces and darker backgrounds can enhance perceived lightness of surfaces. We used maximum likelihood conjoint measurements to simultaneously quantify the strength of those effects. We quantified the extent to which albedo can influence perceived gloss and physical gloss can influence perceived lightness. We modeled the contribution of lightness and gloss and found that increasing lightness reduced perceived gloss by about 32% whereas gloss had a much weaker influence on perceived lightness of about 12%. Moreover, we also investigated how different backgrounds contribute to the perception of lightness and gloss of a surface placed in front. We found that a glossy background reduces slightly perceived lightness of the center and simultaneously enhances its perceived gloss. Lighter backgrounds reduce perceived gloss and perceived lightness. Conjoint measurements lead us to a better understanding of the contextual effects in gloss and lightness perception. Not only do we confirm the importance of contrast in gloss perception and the reduction of the simultaneous contrast with glossy backgrounds, but we also quantify precisely the strength of those effects. PMID:28203352

The Death of a Star: Supernova 1987a. NASA Educational Briefs for the Upper Elementary-Level Classroom.

ERIC Educational Resources Information Center

National Aeronautics and Space Administration, Washington, DC.

This material discusses supernova, the violent death of a massive star, at a level appropriate for upper elementary students. Background information on Supernova 1987a is presented. Observation techniques using visible light, ultraviolet waves, radio waves, neutrinos, X-rays, and gamma-rays are described. A vocabulary list, 11 questions, and 6…

A cost-effective line-based light-balancing technique using adaptive processing.

PubMed

Hsia, Shih-Chang; Chen, Ming-Huei; Chen, Yu-Min

2006-09-01

The camera imaging system has been widely used; however, the displaying image appears to have an unequal light distribution. This paper presents novel light-balancing techniques to compensate uneven illumination based on adaptive signal processing. For text image processing, first, we estimate the background level and then process each pixel with nonuniform gain. This algorithm can balance the light distribution while keeping a high contrast in the image. For graph image processing, the adaptive section control using piecewise nonlinear gain is proposed to equalize the histogram. Simulations show that the performance of light balance is better than the other methods. Moreover, we employ line-based processing to efficiently reduce the memory requirement and the computational cost to make it applicable in real-time systems.

Rejection of randomly coinciding events in Li_2^{100}MoO_4 scintillating bolometers using light detectors based on the Neganov-Luke effect

NASA Astrophysics Data System (ADS)

Chernyak, D. M.; Danevich, F. A.; Dumoulin, L.; Giuliani, A.; Mancuso, M.; Marcillac, P. de; Marnieros, S.; Nones, C.; Olivieri, E.; Poda, D. V.; Tretyak, V. I.

2017-01-01

Random coincidences of nuclear events can be one of the main background sources in low-temperature calorimetric experiments looking for neutrinoless double-beta decay, especially in those searches based on scintillating bolometers embedding the promising double-beta candidate ^{100} Mo, because of the relatively short half-life of the two-neutrino double-beta decay of this nucleus. We show in this work that randomly coinciding events of the two-neutrino double-beta decay of ^{100} Mo in enriched Li_2^{100} MoO_4 detectors can be effectively discriminated by pulse-shape analysis in the light channel if the scintillating bolometer is provided with a Neganov-Luke light detector, which can improve the signal-to-noise ratio by a large factor, assumed here at the level of {˜ }750 on the basis of preliminary experimental results obtained with these devices. The achieved pile-up rejection efficiency results in a very low contribution, of the order of {˜ }6× 10^{-5} counts/(keV\\cdot kg\\cdot y), to the background counting rate in the region of interest for a large volume ({˜ }90 cm^3) Li_2^{100} MoO_4 detector. This background level is very encouraging in view of a possible use of the Li_2^{100} MoO_4 solution for a bolometric tonne-scale next-generation experiment as that proposed in the CUPID project.

Very-High-Energy γ-Ray Observations of the Blazar 1ES 2344+514 with VERITAS

NASA Astrophysics Data System (ADS)

Allen, C.; Archambault, S.; Archer, A.; Benbow, W.; Bird, R.; Bourbeau, E.; Brose, R.; Buchovecky, M.; Buckley, J. H.; Bugaev, V.; Cardenzana, J. V.; Cerruti, M.; Chen, X.; Christiansen, J. L.; Connolly, M. P.; Cui, W.; Daniel, M. K.; Eisch, J. D.; Falcone, A.; Feng, Q.; Fernandez-Alonso, M.; Finley, J. P.; Fleischhack, H.; Flinders, A.; Fortson, L.; Furniss, A.; Gillanders, G. H.; Griffin, S.; Grube, J.; Hütten, M.; Håkansson, N.; Hanna, D.; Hervet, O.; Holder, J.; Hughes, G.; Humensky, T. B.; Johnson, C. A.; Kaaret, P.; Kar, P.; Kelley-Hoskins, N.; Kertzman, M.; Kieda, D.; Krause, M.; Krennrich, F.; Kumar, S.; Lang, M. J.; Maier, G.; McArthur, S.; McCann, A.; Meagher, K.; Moriarty, P.; Mukherjee, R.; Nguyen, T.; Nieto, D.; O'Brien, S.; de Bhróithe, A. O'Faoláin; Ong, R. A.; Otte, A. N.; Park, N.; Petrashyk, A.; Pichel, A.; Pohl, M.; Popkow, A.; Pueschel, E.; Quinn, J.; Ragan, K.; Reynolds, P. T.; Richards, G. T.; Roache, E.; Rovero, A. C.; Rulten, C.; Sadeh, I.; Santander, M.; Sembroski, G. H.; Shahinyan, K.; Telezhinsky, I.; Tucci, J. V.; Tyler, J.; Wakely, S. P.; Weinstein, A.; Wilhelm, A.; Williams, D. A.

2017-10-01

We present very-high-energy γ-ray observations of the BL Lac object 1ES 2344+514 taken by the Very Energetic Radiation Imaging Telescope Array System between 2007 and 2015. 1ES 2344+514 is detected with a statistical significance above the background of 20.8σ in 47.2 h (livetime) of observations, making this the most comprehensive very-high-energy study of 1ES 2344+514 to date. Using these observations, the temporal properties of 1ES 2344+514 are studied on short and long times-scales. We fit a constant-flux model to nightly and seasonally binned light curves and apply a fractional variability test to determine the stability of the source on different time-scales. We reject the constant-flux model for the 2007-2008 and 2014-2015 nightly binned light curves and for the long-term seasonally binned light curve at the >3σ level. The spectra of the time-averaged emission before and after correction for attenuation by the extragalactic background light are obtained. The observed time-averaged spectrum above 200 GeV is satisfactorily fitted (χ2/NDF = 7.89/6) by a power-law function with an index Γ = 2.46 ± 0.06stat ± 0.20sys and extends to at least 8 TeV. The extragalactic-background-light-deabsorbed spectrum is adequately fit (χ2/NDF = 6.73/6) by a power-law function with an index Γ = 2.15 ± 0.06stat ± 0.20sys while an F-test indicates that the power law with an exponential cut-off function provides a marginally better fit (χ2/NDF = 2.56/5) at the 2.1σ level. The source location is found to be consistent with the published radio location and its spatial extent is consistent with a point source.

Spectroscopic detection

DOEpatents

Woskov, Paul P.; Hadidi, Kamal

2003-01-01

In embodiments, spectroscopic monitor monitors modulated light signals to detect low levels of contaminants and other compounds in the presence of background interference. The monitor uses a spectrometer that includes a transmissive modulator capable of causing different frequency ranges to move onto and off of the detector. The different ranges can include those with the desired signal and those selected to subtract background contributions from those with the desired signal. Embodiments of the system are particularly useful for monitoring metal concentrations in combustion effluent.

Amplification of trace amounts of nucleic acids

DOEpatents

Church, George M [Brookline, MA; Zhang, Kun [Brighton, MA

2008-06-17

Methods of reducing background during amplification of small amounts of nucleic acids employ careful analysis of sources of low level contamination. Ultraviolet light can be used to reduce nucleic acid contaminants in reagents and equipment. "Primer-dimer" background can be reduced by judicious design of primers. We have shown clean signal-to-noise with as little as starting material as one single human cell (.about.6 picogram), E. coli cell (.about.5 femtogram) or Prochlorococcus cell (.about.3 femtogram).

Active confocal imaging for visual prostheses

PubMed Central

Jung, Jae-Hyun; Aloni, Doron; Yitzhaky, Yitzhak; Peli, Eli

2014-01-01

There are encouraging advances in prosthetic vision for the blind, including retinal and cortical implants, and other “sensory substitution devices” that use tactile or electrical stimulation. However, they all have low resolution, limited visual field, and can display only few gray levels (limited dynamic range), severely restricting their utility. To overcome these limitations, image processing or the imaging system could emphasize objects of interest and suppress the background clutter. We propose an active confocal imaging system based on light-field technology that will enable a blind user of any visual prosthesis to efficiently scan, focus on, and “see” only an object of interest while suppressing interference from background clutter. The system captures three-dimensional scene information using a light-field sensor and displays only an in-focused plane with objects in it. After capturing a confocal image, a de-cluttering process removes the clutter based on blur difference. In preliminary experiments we verified the positive impact of confocal-based background clutter removal on recognition of objects in low resolution and limited dynamic range simulated phosphene images. Using a custom-made multiple-camera system, we confirmed that the concept of a confocal de-cluttered image can be realized effectively using light field imaging. PMID:25448710

A silicon avalanche photodiode detector circuit for Nd:YAG laser scattering

NASA Astrophysics Data System (ADS)

Hsieh, C.-L.; Haskovec, J.; Carlstrom, T. N.; Deboo, J. C.; Greenfield, C. M.; Snider, R. T.; Trost, P.

1990-06-01

A silicon avalanche photodiode with an internal gain of about 50 to 100 is used in a temperature controlled environment to measure the Nd:YAG laser Thomson scattered spectrum in the wavelength range from 700 to 1150 nm. A charge sensitive preamplifier was developed for minimizing the noise contribution from the detector electronics. Signal levels as low as 20 photoelectrons (S/N = 1) can be detected. Measurements show that both the signal and the variance of the signal vary linearly with the input light level over the range of interest, indicating Poisson statistics. The signal is processed using a 100 ns delay line and a differential amplifier which subtracts the low frequency background light component. The background signal is amplified with a computer controlled variable gain amplifier and is used for an estimate of the measurement error, calibration, and Z sub eff measurements of the plasma. The signal processing was analyzed using a theoretical model to aid the system design and establish the procedure for data error analysis.

Silicon avalanche photodiode detector circuit for Nd:YAG laser scattering

NASA Astrophysics Data System (ADS)

Hsieh, C. L.; Haskovec, J.; Carlstrom, T. N.; DeBoo, J. C.; Greenfield, C. M.; Snider, R. T.; Trost, P.

1990-10-01

A silicon avalanche photodiode with an internal gain of about 50 to 100 is used in a temperature-controlled environment to measure the Nd:YAG laser Thomson scattered spectrum in the wavelength range from 700 to 1150 nm. A charge-sensitive preamplifier has been developed for minimizing the noise contribution from the detector electronics. Signal levels as low as 20 photoelectrons (S/N=1) can be detected. Measurements show that both the signal and the variance of the signal vary linearly with the input light level over the range of interest, indicating Poisson statistics. The signal is processed using a 100 ns delay line and a differential amplifier which subtracts the low-frequency background light component. The background signal is amplified with a computer-controlled variable gain amplifier and is used for an estimate of the measurement error, calibration, and Zeff measurements of the plasma. The signal processing has been analyzed using a theoretical model to aid the system design and establish the procedure for data error analysis.

Synchronization of video recording and laser pulses including background light suppression

NASA Technical Reports Server (NTRS)

Kalshoven, Jr., James E. (Inventor); Tierney, Jr., Michael (Inventor); Dabney, Philip W. (Inventor)

2004-01-01

An apparatus for and a method of triggering a pulsed light source, in particular a laser light source, for predictable capture of the source by video equipment. A frame synchronization signal is derived from the video signal of a camera to trigger the laser and position the resulting laser light pulse in the appropriate field of the video frame and during the opening of the electronic shutter, if such shutter is included in the camera. Positioning of the laser pulse in the proper video field allows, after recording, for the viewing of the laser light image with a video monitor using the pause mode on a standard cassette-type VCR. This invention also allows for fine positioning of the laser pulse to fall within the electronic shutter opening. For cameras with externally controllable electronic shutters, the invention provides for background light suppression by increasing shutter speed during the frame in which the laser light image is captured. This results in the laser light appearing in one frame in which the background scene is suppressed with the laser light being uneffected, while in all other frames, the shutter speed is slower, allowing for the normal recording of the background scene. This invention also allows for arbitrary (manual or external) triggering of the laser with full video synchronization and background light suppression.

Douglas flight deck design philosophy

NASA Technical Reports Server (NTRS)

Oldale, Paul

1990-01-01

The systems experience gained from 17 years of DC-10 operation was used during the design of the MD-11 to automate system operation and reduce crew workload. All functions, from preflight to shutdown at the termination of flight, require little input from the crew. The MD-11 aircraft systems are monitored for proper operation by the Aircraft Systems Controllers (ASC). In most cases, system reconfiguration as a result of a malfunction is automated. Manual input is required for irreversible actions such as engine shutdown, fuel dump, fire agent discharge, or Integrated Drive Generator (IDG) disconnect. During normal operations, when the cockpit is configured for flight, all annunciators on the overhead panel will be extinguished. This Dark Cockpit immediately confirms to the crew that the panels are correctly configured and that no abnormalities are present. Primary systems annunciations are shown in text on the Alert Area of the Engine and Alert Display (EAD). This eliminates the need to scan the overhead. The MD-11 aircraft systems can be manually controlled from the overhead area of the cockpit. The center portion of the overhead panel is composed of the primary aircraft systems panels, which include FUEL, AIR, Electrical (ELEC) and Hydraulic (HYD) systems, which are easily accessible from both flight crew positions. Each Aircraft Systems Controller (ASC) has two automatic channels and a manual mode. All rectangular lights are annunciators. All square lights are combined switches and annunciators called switch/lights. Red switch/lights on the overhead (Level 3 alerts) are for conditions requiring immediate crew action. Amber (Level 2 or Level 1 alerts) indicates a fault or switch out of position requiring awareness or crew interaction. Overhead switches used in normal operating conditions will illuminate blue when in use (Level 0 alerts) such as WING ANTI-ICE - ON. An overhead switch/light with BLACK LETTERING on an amber or red background indicates a system failure and that crew interaction is required. A switch/light with blue or amber lettering and a BLACK BACKGROUND indicates a switch out of normal position and that crew action is necessary only if the system is in manual operation.

Research of the relationships between light dispersion and contrast of the registered image at different background brightness

NASA Astrophysics Data System (ADS)

Stoyanov, Stiliyan; Mardirossian, Garo

2012-10-01

The light diffraction is for telescope apparatuses an especially important characteristic which has an influence on the record image contrast from the eye observer. The task of the investigation is to determine to what degree the coefficient of light diffraction influences the record image brightness. The object of the theoretical research are experimental results provided from a telescope system experiment in the process of observation of remote objects with different brightness of the background in the fixed light diffraction coefficients and permanent contrast of the background in respect to the object. The received values and the ratio of the image contrast to the light diffraction coefficient is shown in a graphic view. It's settled that with increasing of the value of background brightness in permanent background contrast in respect to the object, the image contrast sharply decrease. The relationship between the increase of the light diffraction coefficient and the decrease of the brightness of the project image from telescope apparatuses can be observed.

Saliency Detection on Light Field.

PubMed

Li, Nianyi; Ye, Jinwei; Ji, Yu; Ling, Haibin; Yu, Jingyi

2017-08-01

Existing saliency detection approaches use images as inputs and are sensitive to foreground/background similarities, complex background textures, and occlusions. We explore the problem of using light fields as input for saliency detection. Our technique is enabled by the availability of commercial plenoptic cameras that capture the light field of a scene in a single shot. We show that the unique refocusing capability of light fields provides useful focusness, depths, and objectness cues. We further develop a new saliency detection algorithm tailored for light fields. To validate our approach, we acquire a light field database of a range of indoor and outdoor scenes and generate the ground truth saliency map. Experiments show that our saliency detection scheme can robustly handle challenging scenarios such as similar foreground and background, cluttered background, complex occlusions, etc., and achieve high accuracy and robustness.

Background Light Bluer Than Expected

NASA Image and Video Library

2014-11-06

This plot shows data from the Cosmic Infrared Background Experiment, or CIBER, rockets launched in 2010 and 2012. The experiment measures a diffuse glow of infrared light in the sky, known as the cosmic infrared background.

Light adaptation and dark adaptation of human rod photoreceptors measured from the a-wave of the electroretinogram

PubMed Central

Thomas, M M; Lamb, T D

1999-01-01

We recorded the a-wave of the human electroretinogram from subjects with normal vision, using a corneal electrode and ganzfeld (full-field) light stimulation. From analysis of the rising phase of rod-isolated flash responses we determined the maximum size (amax) of the a-wave, a measure of the massed circulating current of the rods, and the amplification constant (A) of transduction within the rod photoreceptors.During light adaptation by steady backgrounds the maximal response was reduced, as reported previously. amax declined approximately as I0/(I0+IB), where IB is retinal illuminance and I0 is a constant. In different subjects I0 ranged from 40 to 100 trolands, with a mean of 70 trolands, corresponding to about 600 photoisomerizations s−1 per rod. (1 troland is the retinal illuminance that results when a surface luminance of 1 cd m−2 is viewed through a pupil area of 1 mm2.) The amplification constant A decreased only slightly in the presence of steady backgrounds.Following a full bleach amax recovered along an S-shaped curve over a period of 30 min. There was no detectable response for the first 5 min, and half-maximal recovery took 13-17 min.The apparent amplification constant decreased at early times after large bleaches. However, upon correction for reduced light absorption due to loss of pigment, with regeneration of rhodopsin occurring with a time constant of 9-15 min in different subjects, it appeared that the true value of A was probably unchanged by bleaching.The recovery of amax following a bleach could be converted into recovery of equivalent background intensity, using a ‘Crawford transformation’ derived from the light adaptation results. Following bleaches ranging from 10 to > 99 %, the equivalent background intensity decayed approximately exponentially, with a time constant of about 3 min.The time taken for amax to recover to a fixed proportion of its original level increased approximately linearly (rather than logarithmically) with fractional bleach, with a slope of about 12 min per 100 % bleach. Similar behaviour has previously been seen in psychophysical dark adaptation experiments, for the dependence of the ‘second component’ of recovery on the level of bleaching. PMID:10381594

A flexible scintillation light apparatus for rare events searches

NASA Astrophysics Data System (ADS)

Gironi, L.; Baldazzi, G.; Bonvicini, V.; Campana, R.; Capelli, S.; Evangelista, Y.; Fasoli, M.; Feroci, M.; Fuschino, F.; Labanti, C.; Marisaldi, M.; Previtali, E.; Riganese, L.; Rashevsky, A.; Sisti, M.; Vacchi, A.; Vedda, A.; Zampa, G.; Zampa, N.; Zuffa, M.

2016-05-01

FLARES (a Flexible scintillation Light Apparatus for Rare Event Searches) is a project for an innovative detector technology to be applied to rare event searches, and in particular to neutrinoless double beta decay experiments. Its novelty is the enhancement and optimization of the collection of the scintillation light emitted by ultra-pure crystals through the use of arrays of high performance silicon photodetectors cooled to 120 K. This would provide scintillation detectors with ~1% level energy resolution, with the advantages of a technology offering relatively simple low cost mass scalability and powerful background reduction handles, as requested by future neutrinoless double beta decay experimental programs.

Effect of Pulsing in Low-Level Light Therapy

PubMed Central

Hashmi, Javad T.; Huang, Ying-Ying; Sharma, Sulbha K.; Kurup, Divya Balachandran; De Taboada, Luis; Carroll, James D.; Hamblin, Michael R.

2010-01-01

Background and Objective Low level light (or laser) therapy (LLLT) is a rapidly growing modality used in physical therapy, chiropractic, sports medicine and increasingly in mainstream medicine. LLLT is used to increase wound healing and tissue regeneration, to relieve pain and inflammation, to prevent tissue death, to mitigate degeneration in many neurological indications. While some agreement has emerged on the best wavelengths of light and a range of acceptable dosages to be used (irradiance and fluence), there is no agreement on whether continuous wave or pulsed light is best and on what factors govern the pulse parameters to be chosen. Study Design/Materials and Methods The published peer-reviewed literature was reviewed between 1970 and 2010. Results The basic molecular and cellular mechanisms of LLLT are discussed. The type of pulsed light sources available and the parameters that govern their pulse structure are outlined. Studies that have compared continuous wave and pulsed light in both animals and patients are reviewed. Frequencies used in other pulsed modalities used in physical therapy and biomedicine are compared to those used in LLLT. Conclusion There is some evidence that pulsed light does have effects that are different from those of continuous wave light. However further work is needed to define these effects for different disease conditions and pulse structures. PMID:20662021

Human phase response curve to a 1 h pulse of bright white light

PubMed Central

St Hilaire, Melissa A; Gooley, Joshua J; Khalsa, Sat Bir S; Kronauer, Richard E; Czeisler, Charles A; Lockley, Steven W

2012-01-01

The phase resetting response of the human circadian pacemaker to light depends on the timing of exposure and is described by a phase response curve (PRC). The current study aimed to construct a PRC for a 1 h exposure to bright white light (∼8000 lux) and to compare this PRC to a <3 lux dim background light PRC. These data were also compared to a previously completed 6.7 h bright white light PRC and a <15 lux dim background light PRC constructed under similar conditions. Participants were randomized for exposure to 1 h of either bright white light (n= 18) or <3 lux dim background light (n= 18) scheduled at 1 of 18 circadian phases. Participants completed constant routine (CR) procedures in dim light (<3 lux) before and after the light exposure to assess circadian phase. Phase shifts were calculated as the difference in timing of dim light melatonin onset (DLMO) during pre- and post-stimulus CRs. Exposure to 1 h of bright white light induced a Type 1 PRC with a fitted peak-to-trough amplitude of 2.20 h. No discernible PRC was observed in the <3 lux dim background light PRC. The fitted peak-to-trough amplitude of the 1 h bright light PRC was ∼40% of that for the 6.7 h PRC despite representing only 15% of the light exposure duration, consistent with previous studies showing a non-linear duration–response function for the effects of light on circadian resetting. PMID:22547633

Human phase response curve to a 1 h pulse of bright white light.

PubMed

St Hilaire, Melissa A; Gooley, Joshua J; Khalsa, Sat Bir S; Kronauer, Richard E; Czeisler, Charles A; Lockley, Steven W

2012-07-01

The phase resetting response of the human circadian pacemaker to light depends on the timing of exposure and is described by a phase response curve (PRC). The current study aimed to construct a PRC for a 1 h exposure to bright white light (∼8000 lux) and to compare this PRC to a <3 lux dim background light PRC. These data were also compared to a previously completed 6.7 h bright white light PRC and a <15 lux dim background light PRC constructed under similar conditions. Participants were randomized for exposure to 1 h of either bright white light (n=18) or <3 lux dim background light (n=18) scheduled at 1 of 18 circadian phases. Participants completed constant routine (CR) procedures in dim light (<3 lux) before and after the light exposure to assess circadian phase. Phase shifts were calculated as the difference in timing of dim light melatonin onset (DLMO) during pre- and post-stimulus CRs. Exposure to 1 h of bright white light induced a Type 1 PRC with a fitted peak-to-trough amplitude of 2.20 h. No discernible PRC was observed in the <3 lux dim background light PRC. The fitted peak-to-trough amplitude of the 1 h bright light PRC was ∼40% of that for the 6.7 h PRC despite representing only 15% of the light exposure duration, consistent with previous studies showing a non-linear duration–response function for the effects of light on circadian resetting.

Glucose concentration measured by the hybrid coherent anti-Stokes Raman-scattering technique

NASA Astrophysics Data System (ADS)

Wang, Xi; Zhang, Aihua; Zhi, Miaochan; Sokolov, Alexei V.; Welch, George R.

2010-01-01

We investigate the possibility of using a hybrid coherent anti-Stokes Raman scattering technique for noninvasive monitoring of blood glucose levels. Our technique combines instantaneous coherent excitation of several characteristic molecular vibrations with subsequent probing of these vibrations by an optimally shaped, time-delayed, narrowband laser pulse. This pulse configuration mitigates the nonresonant four-wave mixing background while maximizing the Raman-resonant signal and allows rapid and highly specific detection even in the presence of multiple scattering. Under certain conditions we find that the measured signal is linearly proportional to the glucose concentration due to optical interference with the residual background light, which allows reliable detection of spectral signatures down to medically relevant glucose levels.

An investigation of pupil-based cognitive load measurement with low cost infrared webcam under light reflex interference.

PubMed

Chen, Siyuan; Epps, Julien; Chen, Fang

2013-01-01

Using the task-evoked pupillary response (TEPR) to index cognitive load can contribute significantly to the assessment of memory function and cognitive skills in patients. However, the measurement of pupillary response is currently limited to a well-controlled lab environment due to light reflex and also relies heavily on expensive video-based eye trackers. Furthermore, commercial eye trackers are usually dedicated to gaze direction measurement, and their calibration procedure and computing resource are largely redundant for pupil-based cognitive load measurement (PCLM). In this study, we investigate the validity of cognitive load measurement with (i) pupil light reflex in a less controlled luminance background; (ii) a low-cost infrared (IR) webcam for the TEPR in a controlled luminance background. ANOVA results show that with an appropriate baseline selection and subtraction, the light reflex is significantly reduced, suggesting the possibility of less constrained practical applications of PCLM. Compared with the TEPR from a commercial remote eye tracker, a low-cost IR webcam achieved a similar TEPR pattern and no significant difference was found between the two devices in terms of cognitive load measurement across five induced load levels.

Light-induced morphological alteration in anthocyanin-accumulating vacuoles of maize cells

PubMed Central

Irani, Niloufer G; Grotewold, Erich

2005-01-01

Background Plant pigmentation is affected by a variety of factors. Light, an important plant developmental signal, influences the accumulation of anthocyanins primarily through the activation of the transcription factors that regulate the flavonoid biosynthetic pathway. In this study, we utilized maize Black Mexican Sweet (BMS) cells expressing the R and C1 regulators of anthocyanin biosynthesis from a light-insensitive promoter as a means to investigate the existence of additional levels of control of pigmentation by light. Results BMS cells expressing the R and C1 regulators from the CaMV 35S constitutive promoter accumulate anthocyanins when grown in complete darkness, suggesting that the transcription factors R and C1 are sufficient for the transcription of the genes corresponding to the structural enzymes of the pathway, with no requirement for additional light-induced regulators. Interestingly, light induces a "darkening" in the color of the purple anthocyanin pigmentation of transgenic BMS cells expressing R and C1. This change in the pigment hue is not associated with a variation in the levels or types of anthocyanins present, or with an alteration of the transcript levels of several flavonoid biosynthetic genes. However, cytological observations show that light drives unexpected changes in the morphology and distribution of the anthocyanins-containing vacuolar compartments. Conclusion By uncoupling the effect of light on anthocyanin accumulation, we have found light to induce the fusion of anthocyanin-containing vacuoles, the coalescence of anthocyanic vacuolar inclusion (AVI)-like structures contained, and the spread of anthocyanins from the inclusions into the vacuolar sap. Similar light-induced alterations in vacuolar morphology are also evident in the epidermal cells of maize floral whorls accumulating anthocyanins. Our findings suggest a novel mechanism for the action of light on the vacuolar storage of anthocyanin. PMID:15907203

A Study on Mutil-Scale Background Error Covariances in 3D-Var Data Assimilation

NASA Astrophysics Data System (ADS)

Zhang, Xubin; Tan, Zhe-Min

2017-04-01

The construction of background error covariances is a key component of three-dimensional variational data assimilation. There are different scale background errors and interactions among them in the numerical weather Prediction. However, the influence of these errors and their interactions cannot be represented in the background error covariances statistics when estimated by the leading methods. So, it is necessary to construct background error covariances influenced by multi-scale interactions among errors. With the NMC method, this article firstly estimates the background error covariances at given model-resolution scales. And then the information of errors whose scales are larger and smaller than the given ones is introduced respectively, using different nesting techniques, to estimate the corresponding covariances. The comparisons of three background error covariances statistics influenced by information of errors at different scales reveal that, the background error variances enhance particularly at large scales and higher levels when introducing the information of larger-scale errors by the lateral boundary condition provided by a lower-resolution model. On the other hand, the variances reduce at medium scales at the higher levels, while those show slight improvement at lower levels in the nested domain, especially at medium and small scales, when introducing the information of smaller-scale errors by nesting a higher-resolution model. In addition, the introduction of information of larger- (smaller-) scale errors leads to larger (smaller) horizontal and vertical correlation scales of background errors. Considering the multivariate correlations, the Ekman coupling increases (decreases) with the information of larger- (smaller-) scale errors included, whereas the geostrophic coupling in free atmosphere weakens in both situations. The three covariances obtained in above work are used in a data assimilation and model forecast system respectively, and then the analysis-forecast cycles for a period of 1 month are conducted. Through the comparison of both analyses and forecasts from this system, it is found that the trends for variation in analysis increments with information of different scale errors introduced are consistent with those for variation in variances and correlations of background errors. In particular, introduction of smaller-scale errors leads to larger amplitude of analysis increments for winds at medium scales at the height of both high- and low- level jet. And analysis increments for both temperature and humidity are greater at the corresponding scales at middle and upper levels under this circumstance. These analysis increments improve the intensity of jet-convection system which includes jets at different levels and coupling between them associated with latent heat release, and these changes in analyses contribute to the better forecasts for winds and temperature in the corresponding areas. When smaller-scale errors are included, analysis increments for humidity enhance significantly at large scales at lower levels to moisten southern analyses. This humidification devotes to correcting dry bias there and eventually improves forecast skill of humidity. Moreover, inclusion of larger- (smaller-) scale errors is beneficial for forecast quality of heavy (light) precipitation at large (small) scales due to the amplification (diminution) of intensity and area in precipitation forecasts but tends to overestimate (underestimate) light (heavy) precipitation .

Survey of discomfort glare from the headlamps of cars widely used in Iran.

PubMed

Mehri, Ahmad; Farhang Dehghan, Somayeh; Hajizadeh, Roohalah; Zakerian, Seyed Abolfazl; Mohammadi, Hamzeh; Abbasi, Milad

2017-10-03

On 2-lane roads, discomfort glare can cause annoyance, discomfort, inconvenience, stress, and fatigue to drivers, posing a risk of accidents. The aim of this study is to evaluate discomfort glare from the headlamps of cars widely used in Iran. The discomfort glare of new vehicles including Pride Saba model GTX, Pride Model 131SL, Samand Soren, Peugeot 405, Megane, and Peugeot Pars was examined at distances of 5 to 100 m at a background luminance of 50 cd/m 2 (late twilight/early dawn lighting) and 1 cd/m 2 (nighttime) using Schmidt-Clausen and Bindels model and de Boer's subjective scale. According to the de Boer scale, at a background luminance of 50 cd/m 2 , the discomfort glare for all studied vehicles was between 1.98 and 4.05 in high-beam mode and between 3.5 and 5.4 in low-beam mode. At a background luminance of 1 cd/m 2 , discomfort glare was between 0.41 and 2.48 in high-beam mode and between 1.93 and 3.84 in low-beam mode. In high-beam mode, the average levels of discomfort glare of these vehicles gradually increased when the distance between cars was reduced by up to about 20 m. In low-beam mode, there was no discomfort glare up to a vehicle distance of 40 m. In addition, at an angle of 1.15°-5.73° between the line of sight and light of vehicles in high-beam mode, the level of discomfort glare was increased, but at an angle of 5.73°-22.9° the level of discomfort glare was reduced. In low-beam mode at an angle of 2.86°-22.9°, the level of discomfort glare was almost identical. The results show that in high-beam mode and with a 100-m distance between vehicles as well as in low-beam mode at intervals of less than 40 m between cars, discomfort glare is created. It can be concluded that by providing solutions such as installing road lighting system, an increase in luminance of roads, separating or widening road lanes, increasing the lateral distance between vehicles, and increasing the angle between lighted vehicles and drivers can noticeably reduce discomfort glare.

Earth-Space Science Activity Syllabus for Elementary and Junior High School Teachers of Science.

ERIC Educational Resources Information Center

Maier, Jack; And Others

This syllabus is a collection of earth-space science laboratory activities and demonstrations intended for use at the elementary and junior high school levels. The activities are grouped into eight subject sections: Astronomy, Light, Magnetism, Electricity, Geology, Weather, Sound, and Space. Each section begins with brief background information,…

Sedentary and Physical Activity Habits of Obese Adolescents

ERIC Educational Resources Information Center

Starkoff, Brooke E.; Petosa, Rick L.; Balk, Elizabeth K.; Eneli, Ihuoma U.; Bonny, Andrea E.; Hoffman, Robert P.; Devor, Steven T.

2014-01-01

Background: The independent association between sedentary behavior (SB) and physical activity (PA) is such that, regardless of accumulated PA, high amounts of SB are detrimental to health, even in adolescents. Purpose: Our aim was to profile activity patterns in free-living environments and to measure levels of SB and light (LT) and moderate (MOD)…

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.

COSMIC INFRARED BACKGROUND FLUCTUATIONS AND ZODIACAL LIGHT

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

Arendt, Richard G.; Kashlinsky, A.; Moseley, S. H.

We performed a specific observational test to measure the effect that the zodiacal light can have on measurements of the spatial fluctuations of the near-IR background. Previous estimates of possible fluctuations caused by zodiacal light have often been extrapolated from observations of the thermal emission at longer wavelengths and low angular resolution or from IRAC observations of high-latitude fields where zodiacal light is faint and not strongly varying with time. The new observations analyzed here target the COSMOS field at low ecliptic latitude where the zodiacal light intensity varies by factors of ∼2 over the range of solar elongations atmore » which the field can be observed. We find that the white-noise component of the spatial power spectrum of the background is correlated with the modeled zodiacal light intensity. Roughly half of the measured white noise is correlated with the zodiacal light, but a more detailed interpretation of the white noise is hampered by systematic uncertainties that are evident in the zodiacal light model. At large angular scales (≳100″) where excess power above the white noise is observed, we find no correlation of the power with the modeled intensity of the zodiacal light. This test clearly indicates that the large-scale power in the infrared background is not being caused by the zodiacal light.« less

Cosmic Infrared Background Fluctuations and Zodiacal Light

NASA Astrophysics Data System (ADS)

Arendt, Richard G.; Kashlinsky, A.; Moseley, S. H.; Mather, J.

2016-06-01

We performed a specific observational test to measure the effect that the zodiacal light can have on measurements of the spatial fluctuations of the near-IR background. Previous estimates of possible fluctuations caused by zodiacal light have often been extrapolated from observations of the thermal emission at longer wavelengths and low angular resolution or from IRAC observations of high-latitude fields where zodiacal light is faint and not strongly varying with time. The new observations analyzed here target the COSMOS field at low ecliptic latitude where the zodiacal light intensity varies by factors of ˜2 over the range of solar elongations at which the field can be observed. We find that the white-noise component of the spatial power spectrum of the background is correlated with the modeled zodiacal light intensity. Roughly half of the measured white noise is correlated with the zodiacal light, but a more detailed interpretation of the white noise is hampered by systematic uncertainties that are evident in the zodiacal light model. At large angular scales (≳100″) where excess power above the white noise is observed, we find no correlation of the power with the modeled intensity of the zodiacal light. This test clearly indicates that the large-scale power in the infrared background is not being caused by the zodiacal light.

Development and field testing of a Light Aircraft Oil Surveillance System (LAOSS)

NASA Technical Reports Server (NTRS)

Burns, W.; Herz, M. J.

1976-01-01

An experimental device consisting of a conventional TV camera with a low light level photo image tube and motor driven polarized filter arrangement was constructed to provide a remote means of discriminating the presence of oil on water surfaces. This polarized light filtering system permitted a series of successive, rapid changes between the vertical and horizontal components of reflected polarized skylight and caused the oil based substances to be more easily observed and identified as a flashing image against a relatively static water surface background. This instrument was flight tested, and the results, with targets of opportunity and more systematic test site data, indicate the potential usefulness of this airborne remote sensing instrument.

Image and Processing Models for Satellite Detection in Images Acquired by Space-based Surveillance-of-Space Sensors

DTIC Science & Technology

2010-09-01

external sources ‘L1’ like zodiacal light (or diffuse nebula ) or stray light ‘L2’ and these components change with the telescope pointing. Bk (T,t...Astronomical scene background (zodiacal light, diffuse nebulae , etc.). L2(P A(tk), t): Image background component caused by stray light. MS

External occulter edge scattering control using metamaterials for exoplanet detection

NASA Astrophysics Data System (ADS)

Bendek, Eduardo A.; Sirbu, Dan; Liu, Zhaowei; Martin, Stefan; Lu, Dylan

2015-09-01

Direct imaging of earth-like exoplanets in the Habitable Zone of sun-like stars requires image contrast of ~10^10 at angular separations of around a hundred milliarcseconds. One approach for achieving this performance is to fly a starshade at a long distance in front of the telescope, shading the telescope from the direct starlight, but allowing planets around the star to be seen. The starshade is positioned so that sunlight falls on the surface away from the telescope, so the sun does not directly illuminate it. However, sunlight scattered from the starshade edge can enter the telescope, raising the background light level and potentially preventing the starshade from delivering the required contrast. As a result, starshade edge design has been identified as one of the highest priority technology gaps for external occulter missions in the NASAs Exoplanet Exploration Program Technology Plan 2013. To reduce the sunlight edge scatter to an acceptable level, the edge Radius Of Curvature (ROC) should be 1μm or less (commercial razor blades have ROC of a few hundred nanometer). This poses a challenging manufacturing requirement and may make the occulter difficult to handle. In this paper we propose an alternative approach to controlling the edge scattering by applying a flexible metamaterial to the occulter edge. Metamaterials are artificially structured materials, which have been designed to display properties not found in natural materials. Metamaterials can be designed to direct the scatter at planned incident angles away from the space telescope, thereby directly decreasing the contaminating background light. Reduction of the background light translates into shorter integration time to characterize a target planet and therefore improves the efficiency of the observations. As an additional benefit, metamaterials also have potential to produce increased tolerance to edge defects.

A Computational Model of Afterimage Rotation in the Peripheral Drift Illusion Based on Retinal ON/OFF Responses

PubMed Central

Hayashi, Yuichiro; Ishii, Shin; Urakubo, Hidetoshi

2014-01-01

Human observers perceive illusory rotations after the disappearance of circularly repeating patches containing dark-to-light luminance. This afterimage rotation is a very powerful phenomenon, but little is known about the mechanisms underlying it. Here, we use a computational model to show that the afterimage rotation can be explained by a combination of fast light adaptation and the physiological architecture of the early visual system, consisting of ON- and OFF-type visual pathways. In this retinal ON/OFF model, the afterimage rotation appeared as a rotation of focus lines of retinal ON/OFF responses. Focus lines rotated clockwise on a light background, but counterclockwise on a dark background. These findings were consistent with the results of psychophysical experiments, which were also performed by us. Additionally, the velocity of the afterimage rotation was comparable with that observed in our psychophysical experiments. These results suggest that the early visual system (including the retina) is responsible for the generation of the afterimage rotation, and that this illusory rotation may be systematically misinterpreted by our high-level visual system. PMID:25517906

Investigation of breakdown processes in automotive HID lamps

NASA Astrophysics Data System (ADS)

Bergner, Andre; Hoebing, Thomas; Ruhrmann, Cornelia; Mentel, Juergen; Awakowicz, Peter

2011-10-01

HID lamps are used for applications where high lumen output levels are required. Car headlights are a special field of HID lamp application. For security reasons and lawful regulations these lamps have to have a fast run-up phase and the possibility of hot re-strike. Therefore the background gas pressure amounts to 1.5 MPa xenon. But this high background gas pressure has the disadvantage that the ignition voltage becomes quite high due to Paschen's law. For that reason this paper deals with the investigation of the breakdown process of HID lamps for automotive application. The ignition is investigated by electrical as well as optical methods. Ignition voltage and current are measured on a nanosecond time scale and correlated with simultaneous phase resolved high speed photography done by an ICCD camera. So the ignition process can be observed from the first light emission until to the formation of whole discharge channel. The authors gratefully acknowledge the financial support by BMBF within the European project 'SEEL - Solutions for Energy Efficient Lighting' (FKZ: 13N11265). Furthermore the author would like to thank Philips Lighting (Aachen) for valuable discussions.

SOLAR - ASTRONOMY (APOLLO-SATURN [AS]-16)

NASA Image and Video Library

1972-05-09

S72-36972 (21 April 1972) --- A color enhancement of a far-ultraviolet photo of Earth taken by astronaut John W. Young, commander, with the ultraviolet camera on April 21, 1972. The original black and white photo was printed on Agfacontour film three times, each exposure recording only one light level. The three light levels were then colored blue (dimmest), green (next brightest), and red (brightest). The three auroral belts, the sunlit atmosphere and the background stars (one very close to Earth, on left) can be studied quantitatively fro brightness. The UV camera was designed and built at the Naval Research Laboratory, Washington, D.C. EDITOR'S NOTE: The photographic number of the original black & white UV camera photograph from which this enhancement was made is AS16-123-19657.

Lighting and perceptual cues: Effects on gait measures of older adults at high and low risk for falls

PubMed Central

2011-01-01

Background The visual system plays an important role in maintaining balance. As a person ages, gait becomes slower and stride becomes shorter, especially in dimly lighted environments. Falls risk has been associated with reduced speed and increased gait variability. Methods Twenty-four older adults (half identified at risk for falls) experienced three lighting conditions: pathway illuminated by 1) general ceiling-mounted fixtures, 2) conventional plug-in night lights and 3) plug-in night lights supplemented by laser lines outlining the pathway. Gait measures were collected using the GAITRite© walkway system. Results Participants performed best under the general ceiling-mounted light system and worst under the night light alone. The pathway plus night lights increased gait velocity and reduced step length variability compared to the night lights alone in those at greater risk of falling. Conclusions Practically, when navigating in more challenging environments, such as in low-level ambient illumination, the addition of perceptual cues that define the horizontal walking plane can potentially reduce falls risks in older adults. PMID:21864387

Search for the associated production of the Higgs boson with a top quark pair in multilepton final states with the ATLAS detector

DOE PAGES

Aad, G.

2015-08-05

A search for the associated production of the Higgs boson with a top quark pair is performed in multilepton final states using 20.3 fb –1 of proton–proton collision data recorded by the ATLAS experiment at √s=8 TeV at the Large Hadron Collider. The five final states, targeting the decays H → WW*, ττ, and ZZ*, are examined for the presence of the Standard Model (SM) Higgs boson: two same-charge light leptons (e or μ) without a hadronically decaying τ lepton; three light leptons; two same-charge light leptons with a hadronically decaying τ lepton; four light leptons; and one light leptonmore » and two hadronically decaying τ leptons. No significant excess of events is observed above the background expectation. The best fit for the tt¯H production cross section, assuming a Higgs boson mass of 125 GeV, is 2.1 –1.2 +1.4 times the SM expectation, and the observed (expected) upper limit at the 95% confidence level is 4.7 (2.4) times the SM rate. The p-value for compatibility with the background-only hypothesis is 1.8σ; the expectation in the presence of a Standard Model signal is 0.9σ.« less

AdS5×S(5) mirror model as a string sigma model.

PubMed

Arutyunov, Gleb; van Tongeren, Stijn J

2014-12-31

Doing a double Wick rotation in the world sheet theory of the light cone AdS5×S(5) superstring results in an inequivalent, so-called mirror theory that plays a central role in the field of integrability in the AdS-CFT correspondence. We show that this mirror theory can be interpreted as the light cone theory of a free string on a different background. This background is related to dS5×H(5) by a double T-duality, and has hidden supersymmetry. The geometry can also be extracted from an integrable deformation of the AdS5×S(5) sigma model, and we prove the observed mirror duality of these deformed models at the bosonic level as a byproduct. While we focus on AdS5×S(5), our results apply more generally.

The orbital TUS detector simulation

NASA Astrophysics Data System (ADS)

Grinyuk, A.; Grebenyuk, V.; Khrenov, B.; Klimov, P.; Lavrova, M.; Panasyuk, M.; Sharakin, S.; Shirokov, A.; Tkachenko, A.; Tkachev, L.; Yashin, I.

2017-04-01

The TUS space experiment is aimed at studying energy and arrival distribution of UHECR at E > 7 × 1019 eV by using the data of EAS fluorescent radiation in atmosphere. The TUS mission was launched at the end of April 2016 on board the dedicated ;Lomonosov; satellite. The TUSSIM software package has been developed to simulate performance of the TUS detector for the Fresnel mirror optical parameters, the light concentrator of the photo detector, the front end and trigger electronics. Trigger efficiency crucially depends on the background level which varies in a wide range: from 0.2 × 106 to 15 × 106 ph/(m2 μ s sr) at moonless and full moon nights respectively. The TUSSIM algorithms are described and the expected TUS statistics is presented for 5 years of data collection from the 500 km solar-synchronized orbit with allowance for the variability of the background light intensity during the space flight.

Joint Light Tactical Vehicle (JLTV): Background and Issues for Congress

DTIC Science & Technology

2017-01-10

Joint Light Tactical Vehicle (JLTV): Background and Issues for Congress Andrew Feickert Specialist in Military Ground Forces January 10, 2017......Congressional Research Service Summary The Joint Light Tactical Vehicle (JLTV) is being developed by the Army and the Marine Corps as a successor to the High

The response of earthworms (Eisenia fetida) and soil microbes to the crumb rubber material used in artificial turf fields.

PubMed

Pochron, Sharon T; Fiorenza, Andrew; Sperl, Cassandra; Ledda, Brianne; Lawrence Patterson, Charles; Tucker, Clara C; Tucker, Wade; Ho, Yuwan Lisa; Panico, Nicholas

2017-04-01

Municipalities have been replacing grass fields with artificial turf, which uses crumb rubber infill made from recycled tires. Crumb rubber contains hydrocarbons, organic compounds, and heavy metals. Water runoff from crumb rubber fields contains heavy metals. These components can damage the environment. We contaminated topsoil with new crumb rubber and measured its impact on earthworms and soil microbes. Specifically, we compared soil microbe activity and earthworm health, survivorship, and longevity in heat and light stress under two soil regimes: clean topsoil and clean topsoil contaminated with crumb rubber. We then characterized levels of metals, nutrients, and micronutrients of both soil treatments and compared those to published New York soil background levels and to levels set by the New York State Department of Environmental Conservation (DEC) as remediation goals. We found that: 1) contaminated soil did not inhibit microbial respiration rates, 2) earthworm survivorship was not impacted by exposure to contaminated soil, 3) earthworms' ability to cope with heat and light stress remained unchanged after living in contaminated soil, but 4) earthworms living in contaminated soil gained 14% less body weight than did earthworms living in uncontaminated soil. We also found that, with the exception of zinc, heavy metals in our contaminated soil did not exceed the background levels found throughout New York State or the remediation targets set by the DEC. Published by Elsevier Ltd.

Preschool Daily Patterns of Physical Activity Driven by Location and Social Context

ERIC Educational Resources Information Center

Schlechter, Chelsey R.; Rosenkranz, Richard R.; Fees, Bronwyn S.; Dzewaltowski, David A.

2017-01-01

Background: Preschool children are recommended to spend at least 15 minutes/hour (25% time) in light-to-vigorous physical activity (total physical activity, TPA). Preschool provider practices, such as whether children are put in small group or whole-group activities, are likely to affect children's TPA levels during preschool. The current study…

Decision-Making of Chinese Caregivers for Adult Out-of-Home Placement

ERIC Educational Resources Information Center

Chiu, Marcus Y. L.; Hung, Rommel C. H.

2006-01-01

Background: In the light of the existence of lengthy waiting lists for out-of-home placements, this study examines the factors affecting the decision to apply or not to apply for this facility in a city traditionally characterized by a cultural and policy emphasis on family responsibility and by relatively low levels of welfare commitment to…

Cosmic Infrared Background Fluctuations and Zodiacal Light

NASA Technical Reports Server (NTRS)

Arendt, Richard G.; Kashlinsky, A.; Moseley, S. H.; Mather, J.

2017-01-01

We performed a specific observational test to measure the effect that the zodiacal light can have on measurements of the spatial fluctuations of the near-IR (near-infrared)background. Previous estimates of possible fluctuations caused by zodiacal light have often been extrapolated from observations of the thermal emission at longer wavelengths and low angular resolution or from IRAC (Infrared Array Camera) observations of high-latitude fields where zodiacal light is faint and not strongly varying with time. The new observations analyzed here target the COSMOS (Cosmic Evolution Survey) field at low ecliptic latitude where the zodiacal light intensity varies by factors of approximately 2 over the range of solar elongations at which the field can be observed. We find that the white-noise component of the spatial power spectrum of the background is correlated with the modeled zodiacal light intensity. Roughly half of the measured white noise is correlated with the zodiacal light, but a more detailed interpretation of the white noise is hampered by systematic uncertainties that are evident in the zodiacal light model. At large angular scales (greater than or approximately equal to 100 arcseconds) where excess power above the white noise is observed, we find no correlation of the power with the modeled intensity of the zodiacal light. This test clearly indicates that the large-scale power in the infrared background is not being caused by the zodiacal light.

Preliminary assessment of the ATHENA/WFI non-X-ray background

NASA Astrophysics Data System (ADS)

Perinati, Emanuele; Barbera, Marco; Diebold, Sebastian; Guzman, Alejandro; Santangelo, Andrea; Tenzer, Chris

2017-12-01

We present a preliminary assessment of the non-X-ray background for the WFI on board ATHENA conducted at IAAT in the context of the collaborative background and radiation damage working group activities. Our main result is that in the baseline configuration originally assumed for the camera the requirement on the level of non-X-ray background could not be met. In light of the results of Geant4 simulations we propose and discuss a possible optimization of the camera design and pinpoint some open issues to be addressed in the next phase of investigation. One of these concerns the possible contribution to the non-X-ray background from soft protons and ions funneled to the focal plane through the optics. This is not quantified at this stage, here we just briefly report on our ongoing activities aimed at validating the mechanisms of proton scattering at grazing incidence.

Sub-millisecond electron density profile measurement at the JET tokamak with the fast lithium beam emission spectroscopy system

NASA Astrophysics Data System (ADS)

Réfy, D. I.; Brix, M.; Gomes, R.; Tál, B.; Zoletnik, S.; Dunai, D.; Kocsis, G.; Kálvin, S.; Szabolics, T.; JET Contributors

2018-04-01

Diagnostic alkali atom (e.g., lithium) beams are routinely used to diagnose magnetically confined plasmas, namely, to measure the plasma electron density profile in the edge and the scrape off layer region. A light splitting optics system was installed into the observation system of the lithium beam emission spectroscopy diagnostic at the Joint European Torus (JET) tokamak, which allows simultaneous measurement of the beam light emission with a spectrometer and a fast avalanche photodiode (APD) camera. The spectrometer measurement allows density profile reconstruction with ˜10 ms time resolution, absolute position calculation from the Doppler shift, spectral background subtraction as well as relative intensity calibration of the channels for each discharge. The APD system is capable of measuring light intensities on the microsecond time scale. However ˜100 μs integration is needed to have an acceptable signal to noise ratio due to moderate light levels. Fast modulation of the beam up to 30 kHz is implemented which allows background subtraction on the 100 μs time scale. The measurement covers the 0.9 < ρpol < 1.1 range with 6-10 mm optical resolution at the measurement location which translates to 3-5 mm radial resolution at the midplane due to flux expansion. An automated routine has been developed which performs the background subtraction, the relative calibration, and the comprehensive error calculation, runs a Bayesian density reconstruction code, and loads results to the JET database. The paper demonstrates the capability of the APD system by analyzing fast phenomena like pellet injection and edge localized modes.

Compact light-emitting diode lighting ring for video-assisted thoracic surgery.

PubMed

Lu, Ming-Kuan; Chang, Feng-Chen; Wang, Wen-Zhe; Hsieh, Chih-Cheng; Kao, Fu-Jen

2014-01-01

In this work, a foldable ring-shaped light-emitting diode (LED) lighting assembly, designed to attach to a rubber wound retractor, is realized and tested through porcine animal experiments. Enabled by the small size and the high efficiency of LED chips, the lighting assembly is compact, flexible, and disposable while providing direct and high brightness lighting for more uniform background illumination in video-assisted thoracic surgery (VATS). When compared with a conventional fiber bundle coupled light source that is usually used in laparoscopy and endoscopy, the much broader solid angle of illumination enabled by the LED assembly allows greatly improved background lighting and imaging quality in VATS.

Scanning light-sheet microscopy in the whole mouse brain with HiLo background rejection.

PubMed

Mertz, Jerome; Kim, Jinhyun

2010-01-01

It is well known that light-sheet illumination can enable optically sectioned wide-field imaging of macroscopic samples. However, the optical sectioning capacity of a light-sheet macroscope is undermined by sample-induced scattering or aberrations that broaden the thickness of the sheet illumination. We present a technique to enhance the optical sectioning capacity of a scanning light-sheet microscope by out-of-focus background rejection. The technique, called HiLo microscopy, makes use of two images sequentially acquired with uniform and structured sheet illumination. An optically sectioned image is then synthesized by fusing high and low spatial frequency information from both images. The benefits of combining light-sheet macroscopy and HiLo background rejection are demonstrated in optically cleared whole mouse brain samples, using both green fluorescent protein (GFP)-fluorescence and dark-field scattered light contrast.

Scanning light-sheet microscopy in the whole mouse brain with HiLo background rejection

NASA Astrophysics Data System (ADS)

Mertz, Jerome; Kim, Jinhyun

2010-01-01

It is well known that light-sheet illumination can enable optically sectioned wide-field imaging of macroscopic samples. However, the optical sectioning capacity of a light-sheet macroscope is undermined by sample-induced scattering or aberrations that broaden the thickness of the sheet illumination. We present a technique to enhance the optical sectioning capacity of a scanning light-sheet microscope by out-of-focus background rejection. The technique, called HiLo microscopy, makes use of two images sequentially acquired with uniform and structured sheet illumination. An optically sectioned image is then synthesized by fusing high and low spatial frequency information from both images. The benefits of combining light-sheet macroscopy and HiLo background rejection are demonstrated in optically cleared whole mouse brain samples, using both green fluorescent protein (GFP)-fluorescence and dark-field scattered light contrast.

Effects of Music Listening on Cortisol Levels and Propofol Consumption during Spinal Anesthesia

PubMed Central

Koelsch, Stefan; Fuermetz, Julian; Sack, Ulrich; Bauer, Katrin; Hohenadel, Maximilian; Wiegel, Martin; Kaisers, Udo X.; Heinke, Wolfgang

2011-01-01

Background: This study explores effects of instrumental music on the hormonal system (as indicated by serum cortisol and adrenocorticotropic hormone), the immune system (as indicated by immunoglobulin A) and sedative drug requirements during surgery (elective total hip joint replacement under spinal anesthesia with light sedation). This is the first study investigating this issue with a double-blind design using instrumental music. Methodology/Principal Findings: Patients (n = 40) were randomly assigned either to a music group (listening to instrumental music), or to a control group (listening to a non-musical placebo stimulus). Both groups listened to the auditory stimulus about 2 h before, and during the entire intra-operative period (during the intra-operative light sedation, subjects were able to respond lethargically to verbal commands). Results indicate that, during surgery, patients of the music group had a lower propofol consumption, and lower cortisol levels, compared to the control group. Conclusion/Significance: Our data show that listening to music during surgery under regional anesthesia has effects on cortisol levels (reflecting stress-reducing effects) and reduces sedative requirements to reach light sedation. PMID:21716581

On-Orbit Sky Background Measurements with the FOS

NASA Technical Reports Server (NTRS)

Lyons, R. W.; Baity, W. A.; Beaver, E. A.; Cohen, R. D.; Junkkarinen, V. T.; Linsky, J. B.; Bohlin, R. C.

1993-01-01

Observations of the sky background obtained with the Faint Object Spectrograph during 1991-1992 are discussed. Sky light can be an important contributor to the observed count rate in several of the instrument configurations especially when large apertures are used. In general, the sky background is consistent with the pre-launch expectations and showed the expected effects of zodiacal light and diffuse galactic light. In addition to these sources, there is, particularly during the daytime, a highly variable airglow component which includes a number of emission lines. The sky background will have an impact on the reduction and possibly the interpretation of some spectra.

Relation between residential magnetic fields, light-at-night, and nocturnal urine melatonin levels in women: Volume 1 -- Background and purpose, methods, results, discussion. Final report

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

Kaune, W.; Davis, S.; Stevens, R.

Scientists have postulated a link between exposure to magnetic fields and reduced blood melatonin levels. This EPRI study was designed to supplement a National Cancer Institute study (NCI-BC) of magnetic fields, light-at-night, and the risk of breast cancer. By expanding the exposure assessment of the NCI-BC and collecting data on urine melatonin levels, this project provides new insight into a possible magnetic field-melatonin link. It has been proposed that exposure to 60-Hz (power frequency) magnetic fields may increase the risk of breast cancer by suppressing the normal nocturnal rise in melatonin production in the pineal gland. It remains unknown whethermore » the human pineal gland is reproducibly responsive or sensitive to magnetic field exposure, and whether such exposures could alter elements of the endogenous hormonal environment in women that might be important in the etiology of breast cancer. The objective of this research was to investigate whether exposure to power-frequency magnetic fields and/or light-at-night is associated with levels of the primary urinary melatonin metabolite in women without a history of breast cancer.« less

Validating Lidar Depolorization Calibration using Solar Radiation Scattered by Ice Clouds

NASA Technical Reports Server (NTRS)

Liu, Zhao-Yang; McGill, Matthew; Hu, Yong-Xiang; Hostetter, Chris; Winker, David; Vaughan, Mark

2004-01-01

This letter proposes the use of solar background radiation scattered by ice clouds for validating space lidar depolarization calibration. The method takes advantage of the fact that the background light scattered by ice clouds is almost entirely unpolarized. The theory is examined with Cloud Physics Lidar (CPL) background light measurements.

Theoretical study on the ultra-narrow bandwidth tunable atomic filter with electromagnetically induced transparency

NASA Astrophysics Data System (ADS)

Liu, Yang; Li, Shu-qing; Feng, Zhong-ying; Liu, Xiao-fei; Gao, Jin-yue

2016-12-01

To obtain the weak signal light detection from the high background noise, we present a theoretical study on the ultra-narrow bandwidth tunable atomic filter with electromagnetically induced transparency. In a three-level Λ -type atomic system in the rubidium D1 line, the bandwidth of the EIT atomic filter is narrowed to ~6.5 \\text{MHz} . And the single peak transmission of the filter can be up to 86% . Moreover, the transmission wavelength can be tuned by changing the coupling light frequency. This theoretical scheme can also be applied to other alkali atomic systems.

New Target for Cosmic Axion Searches.

PubMed

Baumann, Daniel; Green, Daniel; Wallisch, Benjamin

2016-10-21

Future cosmic microwave background experiments have the potential to probe the density of relativistic species at the subpercent level. This sensitivity allows light thermal relics to be detected up to arbitrarily high decoupling temperatures. Conversely, the absence of a detection would require extra light species never to have been in equilibrium with the Standard Model. In this Letter, we exploit this feature to demonstrate the sensitivity of future cosmological observations to the couplings of axions to photons, gluons, and charged fermions. In many cases, the constraints achievable from cosmology will surpass existing bounds from laboratory experiments and astrophysical observations by orders of magnitude.

Spectroscopic limits to an extragalactic far-ultraviolet background.

PubMed

Martin, C; Hurwitz, M; Bowyer, S

1991-10-01

We use a spectrum of the lowest intensity diffuse far-ultraviolet background obtained from a series of observations in a number of celestial view directions to constrain the properties of the extragalactic FUV background. The mean continuum level, IEG = 280 +/- 35 photons cm-2 s-1 angstrom-1 sr-1, was obtained in a direction with very low H I column density, and this represents a firm upper limit to any extragalactic background in the 1400-1900 angstroms band. Previous work has demonstrated that the far-ultraviolet background includes (depending on a view direction) contributions from dust-scattered Galactic light, high-ionization emission lines, two-photon emission from H II, H2 fluorescence, and the integrated light of spiral galaxies. We find no evidence in the spectrum of line or continuum features that would signify additional extragalactic components. Motivated by the observation of steep BJ and U number count distributions, we have made a detailed comparison of galaxy evolution models to optical and UV data. We find that the observations are difficult to reconcile with a dominant contribution from unclustered, starburst galaxies at low redshifts. Our measurement rules out large ionizing fluxes at z = 0, but cannot strongly constrain the QSO background light, which is expected to be 0.5%-4% of IEG. We present improved limits on radiative lifetimes of massive neutrinos. We demonstrated with a simple model that IGM radiation is unlikely to make a significant contribution to IEG. Since dust scattering could produce a significant part of the continuum in this lowest intensity spectrum, we carried out a series of tests to evaluate this possibility. We find that the spectrum of a nearby target with higher NH I, when corrected for H2 fluorescence, is very similar to the spectrum obtained in the low H I view direction. This is evidence that the majority of the continuum observed at low NH I is also dust reflection, indicating either the existence of a hitherto unidentified dust component, or of a large enhancement in dust scattering efficiency in low-density gas. We also review the effects of an additional dust component on the far-infrared background and on extragalactic FUV observations. We conclude that dust reflection, combined with modest contributions from H II two-photon emission and from the integrated light of late-type galaxies, may account for virtually all of the FUV background in low H I column density directions.

A compact free space quantum key distribution system capable of daylight operation

NASA Astrophysics Data System (ADS)

Benton, David M.; Gorman, Phillip M.; Tapster, Paul R.; Taylor, David M.

2010-06-01

A free space quantum key distribution system has been demonstrated. Consideration has been given to factors such as field of view and spectral width, to cut down the deleterious effect from background light levels. Suitable optical sources such as lasers and RCLEDs have been investigated as well as optimal wavelength choices, always with a view to building a compact and robust system. The implementation of background reduction measures resulted in a system capable of operating in daylight conditions. An autonomous system was left running and generating shared key material continuously for over 7 days.

Reducing lighting energy use in retail display windows

NASA Astrophysics Data System (ADS)

Freyssinier, Jean Paul; Frering, Daniel; Taylor, Jennifer; Narendran, Nadarajah; Rizzo, Patricia

2006-08-01

A field study was conducted at three clothing stores to validate previous laboratory findings indicating that colored LEDs used as background display lighting could: 1) lower the power demand of accent lighting by up to 50 percent; and 2) provide greater attention capture and visual appeal than current lighting practice. Blue LEDs provided a colored background for window mannequins by illuminating white backdrops. Eliminating fluorescent general lighting and reducing the number and wattage of halogen accent lamps in the display windows reduced the lighting power demand by up to 50 percent. During an eight-week period, more than 700 shoppers rated the attractiveness, eye-catching ability, comfort, and visibility of four different lighting conditions. The results of this field study showed that by introducing color contrast between the displayed objects and the background, the power demand of the accent lighting could be reduced by up to 50 percent without sacrificing visual appeal, visibility, ability to capture the attention of shoppers, and the ability to see the colors of the objects on display. Furthermore, the sales of the products on display were not affected by the 50 percent reduction in lighting.

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

Impact of light exposure on thyroid-stimulating hormone results using the Siemens Advia Centaur TSH-3Ultra assay.

PubMed

Armer, Jane; Giles, Diane; Lancaster, Ian; Brownbill, Kathryn

2017-09-01

Background Thyroid-stimulating hormone (TSH) is used as the first-line test of thyroid function. Siemens Healthcare Diagnostics recommend that Siemens Centaur reagents must be protected from light in the assay information and on reagent packaging. We have compared the effect of light exposure on results using Siemens TSH-3Ultra and follicle-stimulating hormone reagents. The thyroid-stimulating hormone reagent includes fluoroscein thiocyanate whereas the follicle-stimulating hormone reagent does not. Methods Three levels of quality controls were analysed using SiemensTSH-3Ultra and follicle-stimulating hormone reagent packs that had been kept protected from light or exposed to light at 6-h intervals for 48 h and then at 96 h. Results Thyroid-stimulating hormone results were significantly lower after exposure of TSH-3Ultra reagent packs to light. Results were >15% lower at all three levels of quality control following 18 h of light exposure and continued to decrease until 96 h. There was no significant difference in follicle-stimulating hormone results whether reagents had been exposed to or protected from light. Conclusions Thyroid-stimulating hormone results but not follicle-stimulating hormone results are lowered after exposure of reagent packs to light. Laboratories must ensure that TSH-3Ultra reagents are not exposed to light and analyse quality control samples on every reagent pack to check that there has not been light exposure prior to delivery. The labelling on TSH-3Ultra reagent packs should reflect the significant effect of light exposure compared with the follicle-stimulating hormone reagent. We propose that the effect of light exposure on binding of fluoroscein thiocyanate to the solid phase antibody causes the falsely low results.

Fitness costs of increased cataract frequency and cumulative radiation dose in natural mammalian populations from Chernobyl.

PubMed

Lehmann, Philipp; Boratyński, Zbyszek; Mappes, Tapio; Mousseau, Timothy A; Møller, Anders P

2016-01-27

A cataract is a clouding of the lens that reduces light transmission to the retina, and it decreases the visual acuity of the bearer. The prevalence of cataracts in natural populations of mammals, and their potential ecological significance, is poorly known. Cataracts have been reported to arise from high levels of oxidative stress and a major cause of oxidative stress is ionizing radiation. We investigated whether elevated frequencies of cataracts are found in eyes of bank voles Myodes glareolus collected from natural populations in areas with varying levels of background radiation in Chernobyl. We found high frequencies of cataracts in voles collected from different areas in Chernobyl. The frequency of cataracts was positively correlated with age, and in females also with the accumulated radiation dose. Furthermore, the number of offspring in female voles was negatively correlated with cataract severity. The results suggest that cataracts primarily develop as a function of ionizing background radiation, most likely as a plastic response to high levels of oxidative stress. It is therefore possible that the elevated levels of background radiation in Chernobyl affect the ecology and fitness of local mammals both directly through, for instance, reduced fertility and indirectly, through increased cataractogenesis.

Floral pathway integrator gene expression mediates gradual transmission of environmental and endogenous cues to flowering time.

PubMed

van Dijk, Aalt D J; Molenaar, Jaap

2017-01-01

The appropriate timing of flowering is crucial for the reproductive success of plants. Hence, intricate genetic networks integrate various environmental and endogenous cues such as temperature or hormonal statues. These signals integrate into a network of floral pathway integrator genes. At a quantitative level, it is currently unclear how the impact of genetic variation in signaling pathways on flowering time is mediated by floral pathway integrator genes. Here, using datasets available from literature, we connect Arabidopsis thaliana flowering time in genetic backgrounds varying in upstream signalling components with the expression levels of floral pathway integrator genes in these genetic backgrounds. Our modelling results indicate that flowering time depends in a quite linear way on expression levels of floral pathway integrator genes. This gradual, proportional response of flowering time to upstream changes enables a gradual adaptation to changing environmental factors such as temperature and light.

Scanning light-sheet microscopy in the whole mouse brain with HiLo background rejection

PubMed Central

Mertz, Jerome; Kim, Jinhyun

2010-01-01

It is well known that light-sheet illumination can enable optically sectioned wide-field imaging of macroscopic samples. However, the optical sectioning capacity of a light-sheet macroscope is undermined by sample-induced scattering or aberrations that broaden the thickness of the sheet illumination. We present a technique to enhance the optical sectioning capacity of a scanning light-sheet microscope by out-of-focus background rejection. The technique, called HiLo microscopy, makes use of two images sequentially acquired with uniform and structured sheet illumination. An optically sectioned image is then synthesized by fusing high and low spatial frequency information from both images. The benefits of combining light-sheet macroscopy and HiLo background rejection are demonstrated in optically cleared whole mouse brain samples, using both green fluorescent protein (GFP)-fluorescence and dark-field scattered light contrast. PMID:20210471

On the proper use of the reduced speed of light approximation

DOE PAGES

Gnedin, Nickolay Y.

2016-12-07

I show that the Reduced Speed of Light (RSL) approximation, when used properly (i.e. as originally designed - only for the local sources but not for the cosmic background), remains a highly accurate numerical method for modeling cosmic reionization. Simulated ionization and star formation histories from the "Cosmic Reionization On Computers" (CROC) project are insensitive to the adopted value of the reduced speed of light for as long as that value does not fall below about 10% of the true speed of light. Here, a recent claim of the failure of the RSL approximation in the Illustris reionization model appearsmore » to be due to the effective speed of light being reduced in the equation for the cosmic background too, and, hence, illustrates the importance of maintaining the correct speed of light in modeling the cosmic background.« less

On the proper use of the reduced speed of light approximation

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

Gnedin, Nickolay Y.

I show that the Reduced Speed of Light (RSL) approximation, when used properly (i.e. as originally designed - only for the local sources but not for the cosmic background), remains a highly accurate numerical method for modeling cosmic reionization. Simulated ionization and star formation histories from the "Cosmic Reionization On Computers" (CROC) project are insensitive to the adopted value of the reduced speed of light for as long as that value does not fall below about 10% of the true speed of light. Here, a recent claim of the failure of the RSL approximation in the Illustris reionization model appearsmore » to be due to the effective speed of light being reduced in the equation for the cosmic background too, and, hence, illustrates the importance of maintaining the correct speed of light in modeling the cosmic background.« less

Ultraviolet luminosity density of the universe during the epoch of reionization

PubMed Central

Mitchell-Wynne, Ketron; Cooray, Asantha; Gong, Yan; Ashby, Matthew; Dolch, Timothy; Ferguson, Henry; Finkelstein, Steven; Grogin, Norman; Kocevski, Dale; Koekemoer, Anton; Primack, Joel; Smidt, Joseph

2015-01-01

The spatial fluctuations of the extragalactic background light trace the total emission from all stars and galaxies in the Universe. A multiwavelength study can be used to measure the integrated emission from first galaxies during reionization when the Universe was about 500 million years old. Here we report arcmin-scale spatial fluctuations in one of the deepest sky surveys with the Hubble Space Telescope in five wavebands between 0.6 and 1.6 μm. We model-fit the angular power spectra of intensity fluctuation measurements to find the ultraviolet luminosity density of galaxies at redshifts greater than 8 to be . This level of integrated light emission allows for a significant surface density of fainter primeval galaxies that are below the point-source detection level in current surveys. PMID:26348033

Ultraviolet luminosity density of the universe during the epoch of reionization

NASA Astrophysics Data System (ADS)

Mitchell-Wynne, Ketron; Cooray, Asantha; Gong, Yan; Ashby, Matthew; Dolch, Timothy; Ferguson, Henry; Finkelstein, Steven; Grogin, Norman; Kocevski, Dale; Koekemoer, Anton; Primack, Joel; Smidt, Joseph

2015-09-01

The spatial fluctuations of the extragalactic background light trace the total emission from all stars and galaxies in the Universe. A multiwavelength study can be used to measure the integrated emission from first galaxies during reionization when the Universe was about 500 million years old. Here we report arcmin-scale spatial fluctuations in one of the deepest sky surveys with the Hubble Space Telescope in five wavebands between 0.6 and 1.6 μm. We model-fit the angular power spectra of intensity fluctuation measurements to find the ultraviolet luminosity density of galaxies at redshifts greater than 8 to be . This level of integrated light emission allows for a significant surface density of fainter primeval galaxies that are below the point-source detection level in current surveys.

Variation in Educational Outcomes and Policies across Countries and of Schools within Countries. CEE DP 117

ERIC Educational Resources Information Center

Freeman, Richard B.; Machin, Stephen J.; Viarengo, Martina G.

2010-01-01

The motivation for this paper is to increase individuals' understanding of the way in which inequality in educational outcomes and in the relation between measures of backgrounds is related to levels and dispersion of educational performance of young persons. The article thus sheds light on the international variation in the importance of…

Separation of foreground and background from light field using gradient information.

PubMed

Lee, Jae Young; Park, Rae-Hong

2017-02-01

Studies of computer vision or machine vision applications using a light field camera have been increasing in recent years. However, the abilities that the light field camera has are not fully used in these applications. In this paper, we propose a method for direct separation of foreground and background that uses the gradient information and can be used in various applications such as pre-processing. From an optical phenomenon whereby the bundles of rays from the background are flipped, we derive that the disparity sign of the background in the captured three-dimensional scene has the opposite disparity sign of the foreground. Using the majority-weighted voting algorithm based on the gradient information with the Lambertian assumption and the gradient constraint, the foreground and background can be separated at each pixel. In regard to pre-processing, the proposed method can be used for various applications such as occlusion and saliency detection, disparity estimation, and so on. Experimental results with the EPFL light field dataset and Stanford Lytro light field dataset show that the proposed method achieves better performance in terms of the occlusion detection, and thus can be effectively used in pre-processing for saliency detection and disparity estimation.

Zeaxanthin Accumulation in the Absence of a Functional Xanthophyll Cycle Protects Chlamydomonas reinhardtii from Photooxidative Stress

PubMed Central

Baroli, Irene; Do, An D.; Yamane, Tomoko; Niyogi, Krishna K.

2003-01-01

Xanthophylls participate in light harvesting and are essential in protecting the chloroplast from photooxidative damage. To investigate the roles of xanthophylls in photoprotection, we isolated and characterized extragenic suppressors of the npq1 lor1 double mutant of Chlamydomonas reinhardtii, which lacks zeaxanthin and lutein and undergoes irreversible photooxidative bleaching and cell death at moderate to high light intensities. Here, we describe three suppressor strains that carry point mutations in the coding sequence of the zeaxanthin epoxidase gene, resulting in the constitutive accumulation of zeaxanthin in a range of concentrations. The presence of zeaxanthin in these strains was sufficient to prevent photooxidative damage in the npq1 lor1 background. The size of the light-harvesting antenna in the suppressors decreased in high light in a manner that was proportional to the relative content of zeaxanthin, with the strain having the most zeaxanthin showing a severe reduction in levels of the major light-harvesting complex II proteins in high light. We show that the effect of constitutive zeaxanthin on light harvesting is not the main cause of increased photoprotection, because in the absence of zeaxanthin, a strain with a smaller light-harvesting antenna showed only minor protection against photobleaching in high light. Furthermore, the zeaxanthin-accumulating suppressors were able to tolerate higher levels of exogenous reactive oxygen than their parental strain under conditions that did not affect light harvesting. Our results are consistent with an antioxidant role of zeaxanthin in the quenching of singlet oxygen and/or free radicals in the thylakoid membrane in vivo. PMID:12671093

Stochastic dark energy from inflationary quantum fluctuations

NASA Astrophysics Data System (ADS)

Glavan, Dražen; Prokopec, Tomislav; Starobinsky, Alexei A.

2018-05-01

We study the quantum backreaction from inflationary fluctuations of a very light, non-minimally coupled spectator scalar and show that it is a viable candidate for dark energy. The problem is solved by suitably adapting the formalism of stochastic inflation. This allows us to self-consistently account for the backreaction on the background expansion rate of the Universe where its effects are large. This framework is equivalent to that of semiclassical gravity in which matter vacuum fluctuations are included at the one loop level, but purely quantum gravitational fluctuations are neglected. Our results show that dark energy in our model can be characterized by a distinct effective equation of state parameter (as a function of redshift) which allows for testing of the model at the level of the background.

Light adaptation alters inner retinal inhibition to shape OFF retinal pathway signaling

PubMed Central

Mazade, Reece E.

2016-01-01

The retina adjusts its signaling gain over a wide range of light levels. A functional result of this is increased visual acuity at brighter luminance levels (light adaptation) due to shifts in the excitatory center-inhibitory surround receptive field parameters of ganglion cells that increases their sensitivity to smaller light stimuli. Recent work supports the idea that changes in ganglion cell spatial sensitivity with background luminance are due in part to inner retinal mechanisms, possibly including modulation of inhibition onto bipolar cells. To determine how the receptive fields of OFF cone bipolar cells may contribute to changes in ganglion cell resolution, the spatial extent and magnitude of inhibitory and excitatory inputs were measured from OFF bipolar cells under dark- and light-adapted conditions. There was no change in the OFF bipolar cell excitatory input with light adaptation; however, the spatial distributions of inhibitory inputs, including both glycinergic and GABAergic sources, became significantly narrower, smaller, and more transient. The magnitude and size of the OFF bipolar cell center-surround receptive fields as well as light-adapted changes in resting membrane potential were incorporated into a spatial model of OFF bipolar cell output to the downstream ganglion cells, which predicted an increase in signal output strength with light adaptation. We show a prominent role for inner retinal spatial signals in modulating the modeled strength of bipolar cell output to potentially play a role in ganglion cell visual sensitivity and acuity. PMID:26912599

Light-dependent activation of phosphoenolpyruvate carboxylase by reversible phosphorylation in cluster roots of white lupin plants: diurnal control in response to photosynthate supply

PubMed Central

Feil, Regina; Lunn, John E.; Plaxton, William C.

2016-01-01

Background and Aims Phosphoenolpyruvate carboxylase (PEPC) is a tightly regulated enzyme that controls carbohydrate partitioning to organic acid anions (malate, citrate) excreted in copious amounts by cluster roots of inorganic phosphate (Pi)-deprived white lupin plants. Excreted malate and citrate solubilize otherwise inaccessible sources of mineralized soil Pi for plant uptake. The aim of this study was to test the hypotheses that (1) PEPC is post-translationally activated by reversible phosphorylation in cluster roots of illuminated white lupin plants, and (2) light-dependent phosphorylation of cluster root PEPC is associated with elevated intracellular levels of sucrose and its signalling metabolite, trehalose-6-phosphate. Methods White lupin plants were cultivated hydroponically at low Pi levels (≤1 µm) and subjected to various light/dark pretreatments. Cluster root PEPC activity and in vivo phosphorylation status were analysed to assess the enzyme’s diurnal, post-translational control in response to light and dark. Levels of various metabolites, including sucrose and trehalose-6-phosphate, were also quantified in cluster root extracts using enzymatic and spectrometric methods. Key Results During the daytime the cluster root PEPC was activated by phosphorylation at its conserved N-terminal seryl residue. Darkness triggered a progressive reduction in PEPC phosphorylation to undetectable levels, and this was correlated with 75–80 % decreases in concentrations of sucrose and trehalose-6- phosphate. Conclusions Reversible, light-dependent regulatory PEPC phosphorylation occurs in cluster roots of Pi-deprived white lupin plants. This likely facilitates the well-documented light- and sucrose-dependent exudation of Pi-solubilizing organic acid anions by the cluster roots. PEPC’s in vivo phosphorylation status appears to be modulated by sucrose translocated from CO2-fixing leaves into the non-photosynthetic cluster roots. PMID:27063365

The cosmic infrared background experiment-2 (CIBER-2) for studying the near-infrared extragalactic background light

NASA Astrophysics Data System (ADS)

Shirahata, Mai; Arai, Toshiaki; Battle, John; Bock, James; Cooray, Asantha; Enokuchi, Akito; Hristov, Viktor; Kanai, Yoshikazu; Kim, Min Gyu; Korngut, Phillip; Lanz, Alicia; Lee, Dae-Hee; Mason, Peter; Matsumoto, Toshio; Matsuura, Shuji; Morford, Tracy; Ohnishi, Yosuke; Park, Won-Kee; Sano, Kei; Takeyama, Norihide; Tsumura, Kohji; Wada, Takehiko; Wang, Shiang-Yu; Zemcov, Michael

2016-07-01

We present the current status of the Cosmic Infrared Background ExpeRiment-2 (CIBER-2) project, whose goal is to make a rocket-borne measurement of the near-infrared Extragalactic Background Light (EBL), under a collaboration with U.S.A., Japan, South Korea, and Taiwan. The EBL is the integrated light of all extragalactic sources of emission back to the early Universe. At near-infrared wavelengths, measurement of the EBL is a promising way to detect the diffuse light from the first collapsed structures at redshift z˜10, which are impossible to detect as individual sources. However, recently, the intra-halo light (IHL) model is advocated as the main contribution to the EBL, and our new result of the EBL fluctuation from CIBER-1 experiment is also supporting this model. In this model, EBL is contributed by accumulated light from stars in the dark halo regions of low- redshift (z<2) galaxies, those were tidally stripped by the interaction of satellite dwarf galaxies. Thus, in order to understand the origin of the EBL, both the spatial fluctuation observations with multiple wavelength bands and the absolute spectroscopic observations for the EBL are highly required. After the successful initial CIBER- 1 experiment, we are now developing a new instrument CIBER-2, which is comprised of a 28.5-cm aluminum telescope and three broad-band, wide-field imaging cameras. The three wide-field (2.3×2.3 degrees) imaging cameras use the 2K×2K HgCdTe HAWAII-2RG arrays, and cover the optical and near-infrared wavelength range of 0.5-0.9 μm, 1.0-1.4 μm and 1.5-2.0 μm, respectively. Combining a large area telescope with the high sensitivity detectors, CIBER-2 will be able to measure the spatial fluctuations in the EBL at much fainter levels than those detected in previous CIBER-1 experiment. Additionally, we will use a linear variable filter installed just above the detectors so that a measurement of the absolute spectrum of the EBL is also possible. In this paper, the scientific motivation and the expected performance for CIBER-2 will be presented. The detailed designs of the telescope and imaging cameras will also be discussed, including the designs of the mechanical, cryogenic, and electrical systems.

Differential Regulation of Duplicate Light-Dependent Protochlorophyllide Oxidoreductases in the Diatom Phaeodactylum tricornutum

PubMed Central

Hunsperger, Heather M.; Cattolico, Rose Ann

2016-01-01

Background Diatoms (Bacilliariophyceae) encode two light-dependent protochlorophyllide oxidoreductases (POR1 and POR2) that catalyze the penultimate step of chlorophyll biosynthesis in the light. Algae live in dynamic environments whose changing light levels induce photoacclimative metabolic shifts, including altered cellular chlorophyll levels. We hypothesized that the two POR proteins may be differentially adaptive under varying light conditions. Using the diatom Phaeodactylum tricornutum as a test system, differences in POR protein abundance and por gene expression were examined when this organism was grown on an alternating light:dark cycles at different irradiances; exposed to continuous light; and challenged by a significant decrease in light availability. Results For cultures maintained on a 12h light: 12h dark photoperiod at 200μE m−2 s−1 (200L/D), both por genes were up-regulated during the light and down-regulated in the dark, though por1 transcript abundance rose and fell earlier than that of por2. Little concordance occurred between por1 mRNA and POR1 protein abundance. In contrast, por2 mRNA and POR2 protein abundances followed similar diurnal patterns. When 200L/D P. tricornutum cultures were transferred to continuous light (200L/L), the diurnal regulatory pattern of por1 mRNA abundance but not of por2 was disrupted, and POR1 but not POR2 protein abundance dropped steeply. Under 1200μE m−2 s−1 (1200L/D), both por1 mRNA and POR1 protein abundance displayed diurnal oscillations. A compromised diel por2 mRNA response under 1200L/D did not impact the oscillation in POR2 abundance. When cells grown at 1200L/D were then shifted to 50μE m−2 s−1 (50L/D), por1 and por2 mRNA levels decreased swiftly but briefly upon light reduction. Thereafter, POR1 but not POR2 protein levels rose significantly in response to this light stepdown. Conclusion Given the sensitivity of diatom por1/POR1 to real-time light cues and adherence of por2/POR2 regulation to the diurnal cycle, we suggest that POR1 supports photoacclimation, whereas POR2 is the workhorse for daily chlorophyll synthesis. PMID:27367227

Communicating awareness of light pollution with the schools in Nepal

NASA Astrophysics Data System (ADS)

Acharya, Jayanta

2015-08-01

Nepal is also highly polluted by the lights and other dusts partials, but lacks the formal education of light pollutions and effect of light for astronomy observations. When we get Sky Quality Meter (SQM) last year (2014) we have installed it in Kathmandu.This paper will highlight about installation SQM in Nepal, measurement of brightness of the night sky in magnitudes per square arc second. Research work of light pollution of Kathmandu will be more in focus. Highlight of the Astronomy programs by different Schools in Nepal along with the background of coverage of Astronomy education in the syllables of different education level. The various procedure , technique and idea used in providing the space education through different activities and program to school studentsThe paper will also deal with the Importance of light and use of artificial light. Beside it will also highlight the possibility of development of various observatories in Nepal because of its tremendous topography increasing the Astro tourism in Nepal.Hence the paper would focus on the light pollution of the city like Kathmandu and light system in Nepal and Astronomy education to its implementation along with its outreach to Nepalese society.

Low-temperature relative reflectivity measurements of reflective and scintillating foils used in rare event searches

NASA Astrophysics Data System (ADS)

Langenkämper, A.; Ulrich, A.; Defay, X.; Feilitzsch, F. v.; Lanfranchi, J.-C.; Mondragón, E.; Münster, A.; Oppenheimer, C.; Potzel, W.; Roth, S.; Schönert, S.; Steiger, H.; Trinh Thi, H. H.; Wawoczny, S.; Willers, M.; Zöller, A.

2018-03-01

In this work we investigate the reflectivity of highly reflective multilayer polymer foils used in the CRESST experiment. The CRESST experiment searches directly for dark matter via operating scintillating CaWO4 crystals as targets for elastic dark matter-nucleon scattering. In order to suppress background events, the experiment employs the so-called phonon-light technique which is based on the simultaneous measurement of the heat signal in the main CaWO4 target crystal and of the emitted scintillation light with a separate cryogenic light detector. Both detectors are surrounded by a highly reflective and scintillating multilayer polymer foil to increase the light collection efficiency and to veto surface backgrounds. While this study is motivated by the CRESST experiment, the results are also relevant for other rare event searches using scintillating cryogenic bolometers in the field of the search of dark matter and neutrinoless double beta decay (0 νββ). In this work a dedicated experiment has been set up to determine the relative reflectivity at 300 K and 20 K of three multilayer foils ("VM2000", "VM2002", "Vikuiti") produced by the company 3M. The intensity of a light beam reflected off the foil is measured with a CCD camera. The ratio of the intensities at 300 K and 20 K corresponds to the relative reflectivity change. The measurements performed in this work show no variation of the reflectivity with temperature at a level of ∼1%.

ON THE PROPER USE OF THE REDUCED SPEED OF LIGHT APPROXIMATION

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

Gnedin, Nickolay Y., E-mail: gnedin@fnal.gov

I show that the reduced speed of light (RSL) approximation, when used properly (i.e., as originally designed—only for local sources but not for the cosmic background), remains a highly accurate numerical method for modeling cosmic reionization. Simulated ionization and star formation histories from the “Cosmic Reionization on Computers” project are insensitive to the adopted value of the RSL for as long as that value does not fall below about 10% of the true speed of light. A recent claim of the failure of the RSL approximation in the Illustris reionization model appears to be due to the effective speed ofmore » light being reduced in the equation for the cosmic background too and hence illustrates the importance of maintaining the correct speed of light in modeling the cosmic background.« less

Searching Neutrinoless Double Beta Decay with GERDA Phase II

NASA Astrophysics Data System (ADS)

Agostini, M.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Baudis, L.; Bauer, C.; Bellotti, E.; Belogurov, S.; Bettini, A.; Bezrukov, L.; Bode, T.; Brudanin, V.; Brugnera, R.; Caldwell, A.; Cattadori, C.; Chernogorov, A.; Comellato, T.; D’Andrea, V.; Demidova, E. V.; di Marco, N.; Domula, A.; Doroshkevich, E.; Egorov, V.; Falkenstein, R.; Gangapshev, A.; Garfagnini, A.; Giordano, M.; Gooch, C.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Hahne, C.; Hakenmüller, J.; Hegai, A.; Heisel, M.; Hemmer, S.; Hiller, R.; Hofmann, W.; Holl, P.; Hult, M.; Inzhechik, L. V.; Ioannucci, L.; Csáthy, J. Janicskó; Jochum, J.; Junker, M.; Kazalov, V.; Kermaidic, Y.; Kihm, T.; Kirpichnikov, I. V.; Kirsch, A.; Kish, A.; Klimenko, A.; Kneißl, R.; Knöpfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kuzminov, V. V.; Laubenstein, M.; Lazzaro, A.; Lindner, M.; Lippi, I.; Lubashevskiy, A.; Lubsandorzhiev, B.; Lutter, G.; Macolino, C.; Majorovits, B.; Maneschg, W.; Marissens, G.; Miloradovic, M.; Mingazheva, R.; Misiaszek, M.; Moseev, P.; Nemchenok, I.; Nisi, S.; Panas, K.; Pandola, L.; Pelczar, K.; Pullia, A.; Ransom, C.; Reissfelder, M.; Riboldi, S.; Rumyantseva, N.; Sada, C.; Sala, E.; Salamida, F.; Schmitt, C.; Schneider, B.; Schreiner, J.; Schulz, O.; Schweisshelm, B.; Schwingenheuer, B.; Schönert, S.; Schütz, A.-K.; Seitz, H.; Selivanenko, O.; Shevchik, E.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Vanhoefer, L.; Vasenko, A. A.; Veresnikova, A.; von Sturm, K.; Wagner, V.; Wegmann, A.; Wester, T.; Wiesinger, C.; Wojcik, M.; Yanovich, E.; Zhitnikov, I.; Zhukov, S. V.; Zinatulina, D.; Zschocke, A.; Zsigmond, A. J.; Zuber, K.; Zuzel, G.

An observation of neutrinoless double beta (0νββ) decay would allow to shed light onto the nature of neutrinos. GERDA (GERmanium Detector Array) aims to discover this process in a background-free search using 76Ge. The experiment is located at the Laboratori Nazionali del Gran Sasso (LNGS) of the Istituto Nazionale di Fisica Nucleare (INFN) in Italy. Bare, isotopically enriched, high purity germanium detectors are operated in liquid argon. GERDA follows a staged approach. In Phase II 35.6 kg of enriched germanium detectors are operated since December 2015. The application of active background rejection methods, such as a liquid argon scintillation light read-out and pulse shape discrimination of germanium detector signals, allows to reduce the background index to the intended level of 10‑3 cts/(keVṡkgṡyr). No evidence for the 0νββ decay has been found in 23.2 kgṡyr of Phase II data, and together with data from Phase I the up-to-date most stringent half-life limit for this process in 76Ge has been established, at a median sensitivity of 5.8ṡ1025yr the 90% C.L. lower limit is 8.0ṡ1025yr.

DARK-FIELD ILLUMINATION SYSTEM

DOEpatents

Norgren, D.U.

1962-07-24

A means was developed for viewing objects against a dark background from a viewing point close to the light which illuminates the objects and under conditions where the back scattering of light by the objects is minimal. A broad light retro-directing member on the opposite side of the objects from the light returns direct light back towards the source while directing other light away from the viewing point. The viewing point is offset from the light and thus receives only light which is forwardly scattered by an object while returning towards the source. The object is seen, at its true location, against a dark background. The invention is particularly adapted for illuminating and viewing nuclear particle tracks in a liquid hydrogen bubble chamber through a single chamber window. (AEC)

Dual-labeling with 5-aminolevulinic acid and fluorescein for fluorescence-guided resection of high-grade gliomas: technical note.

PubMed

Suero Molina, Eric; Wölfer, Johannes; Ewelt, Christian; Ehrhardt, André; Brokinkel, Benjamin; Stummer, Walter

2018-02-01

OBJECTIVE Fluorescence guidance with 5-aminolevulinic acid (5-ALA) helps improve resections of malignant gliomas. However, one limitation is the low intensity of blue light for background illumination. Fluorescein has recently been reintroduced into neurosurgery, and novel microscope systems are available for visualizing this fluorochrome, which highlights all perfused tissues but has limited selectivity for tumor detection. Here, the authors investigate a combination of both fluorochromes: 5-ALA for distinguishing tumor and fluorescein for providing tissue fluorescence of adjacent brain tissue. METHODS The authors evaluated 6 patients who harbored cerebral lesions suggestive of high-grade glioma. Patients received 5-ALA (20 mg/kg) orally 4 hours before induction of anesthesia. Low-dose fluorescein (3 mg/kg intravenous) was injected immediately after anesthesia induction. Pentero microscopes (equipped either with Yellow 560 or Blue 400 filters) were used to visualize fluorescence. To simultaneously visualize both fluorochromes, the Yellow 560 module was combined with external blue light illumination (D-light C System). RESULTS Fluorescein-induced fluorescence created a useful background for protoporphyrin IX (PPIX) fluorescence, which appeared orange to red, surrounded by greenly fluorescent normal brain and edematous tissue. Green brain-tissue fluorescence was helpful in augmenting background. Levels of blue illumination that were too strong obscured PPIX fluorescence. Unspecific extravasation of fluorescein was noted at resection margins, which did not interfere with PPIX fluorescence detection. CONCLUSIONS Dual labeling with both PPIX and fluorescein fluorescence is feasible and gives superior background information during fluorescence-guided resections. The authors believe that this technique carries potential as a next step in fluorescence-guided resections if it is completely integrated into the surgical microscope.

Rapid perceptual adaptation to high gravitoinertial force levels Evidence for context-specific adaptation

NASA Technical Reports Server (NTRS)

Lackner, J. R.; Graybiel, A.

1982-01-01

Subjects exposed to periodic variations in gravitoinertial force (2-G peak) in parabolic flight maneuvers quickly come to perceive the peak force level as having decreased in intensity. By the end of a 40-parabola flight, the decrease in apparent force is approximately 40%. On successive flight days, the apparent intensity of the force loads seems to decrease as well, indicating a cumulative adaptive effect. None of the subjects reported feeling abnormally 'light' for more than a minute or two after return to 1-G background force levels. The pattern of findings suggests a context-specific adaptation to high-force levels.

Phototropins But Not Cryptochromes Mediate the Blue Light-Specific Promotion of Stomatal Conductance, While Both Enhance Photosynthesis and Transpiration under Full Sunlight12[C][W][OA

PubMed Central

Boccalandro, Hernán E.; Giordano, Carla V.; Ploschuk, Edmundo L.; Piccoli, Patricia N.; Bottini, Rubén; Casal, Jorge J.

2012-01-01

Leaf epidermal peels of Arabidopsis (Arabidopsis thaliana) mutants lacking either phototropins 1 and 2 (phot1 and phot2) or cryptochromes 1 and 2 (cry1 and cry2) exposed to a background of red light show severely impaired stomatal opening responses to blue light. Since phot and cry are UV-A/blue light photoreceptors, they may be involved in the perception of the blue light-specific signal that induces the aperture of the stomatal pores. In leaf epidermal peels, the blue light-specific effect saturates at low irradiances; therefore, it is considered to operate mainly under the low irradiance of dawn, dusk, or deep canopies. Conversely, we show that both phot1 phot2 and cry1 cry2 have reduced stomatal conductance, transpiration, and photosynthesis, particularly under the high irradiance of full sunlight at midday. These mutants show compromised responses of stomatal conductance to irradiance. However, the effects of phot and cry on photosynthesis were largely nonstomatic. While the stomatal conductance phenotype of phot1 phot2 was blue light specific, cry1 cry2 showed reduced stomatal conductance not only in response to blue light, but also in response to red light. The levels of abscisic acid were elevated in cry1 cry2. We conclude that considering their effects at high irradiances cry and phot are critical for the control of transpiration and photosynthesis rates in the field. The effects of cry on stomatal conductance are largely indirect and involve the control of abscisic acid levels. PMID:22147516

Phototropins but not cryptochromes mediate the blue light-specific promotion of stomatal conductance, while both enhance photosynthesis and transpiration under full sunlight.

PubMed

Boccalandro, Hernán E; Giordano, Carla V; Ploschuk, Edmundo L; Piccoli, Patricia N; Bottini, Rubén; Casal, Jorge J

2012-03-01

Leaf epidermal peels of Arabidopsis (Arabidopsis thaliana) mutants lacking either phototropins 1 and 2 (phot1 and phot2) or cryptochromes 1 and 2 (cry1 and cry2) exposed to a background of red light show severely impaired stomatal opening responses to blue light. Since phot and cry are UV-A/blue light photoreceptors, they may be involved in the perception of the blue light-specific signal that induces the aperture of the stomatal pores. In leaf epidermal peels, the blue light-specific effect saturates at low irradiances; therefore, it is considered to operate mainly under the low irradiance of dawn, dusk, or deep canopies. Conversely, we show that both phot1 phot2 and cry1 cry2 have reduced stomatal conductance, transpiration, and photosynthesis, particularly under the high irradiance of full sunlight at midday. These mutants show compromised responses of stomatal conductance to irradiance. However, the effects of phot and cry on photosynthesis were largely nonstomatic. While the stomatal conductance phenotype of phot1 phot2 was blue light specific, cry1 cry2 showed reduced stomatal conductance not only in response to blue light, but also in response to red light. The levels of abscisic acid were elevated in cry1 cry2. We conclude that considering their effects at high irradiances cry and phot are critical for the control of transpiration and photosynthesis rates in the field. The effects of cry on stomatal conductance are largely indirect and involve the control of abscisic acid levels.

Continuous background light significantly increases flashing-light enhancement of photosynthesis and growth of microalgae.

PubMed

Abu-Ghosh, Said; Fixler, Dror; Dubinsky, Zvy; Iluz, David

2015-01-01

Under specific conditions, flashing light enhances the photosynthesis rate in comparison to continuous illumination. Here we show that a combination of flashing light and continuous background light with the same integrated photon dose as continuous or flashing light alone can be used to significantly enhance photosynthesis and increase microalgae growth. To test this hypothesis, the green microalga Dunaliella salina was exposed to three different light regimes: continuous light, flashing light, and concomitant application of both. Algal growth was compared under three different integrated light quantities; low, intermediate, and moderately high. Under the combined light regime, there was a substantial increase in all algal growth parameters, with an enhanced photosynthesis rate, within 3days. Our strategy demonstrates a hitherto undescribed significant increase in photosynthesis and algal growth rates, which is beyond the increase by flashing light alone. Copyright © 2015 Elsevier Ltd. All rights reserved.

Perceptual transparency from image deformation.

PubMed

Kawabe, Takahiro; Maruya, Kazushi; Nishida, Shin'ya

2015-08-18

Human vision has a remarkable ability to perceive two layers at the same retinal locations, a transparent layer in front of a background surface. Critical image cues to perceptual transparency, studied extensively in the past, are changes in luminance or color that could be caused by light absorptions and reflections by the front layer, but such image changes may not be clearly visible when the front layer consists of a pure transparent material such as water. Our daily experiences with transparent materials of this kind suggest that an alternative potential cue of visual transparency is image deformations of a background pattern caused by light refraction. Although previous studies have indicated that these image deformations, at least static ones, play little role in perceptual transparency, here we show that dynamic image deformations of the background pattern, which could be produced by light refraction on a moving liquid's surface, can produce a vivid impression of a transparent liquid layer without the aid of any other visual cues as to the presence of a transparent layer. Furthermore, a transparent liquid layer perceptually emerges even from a randomly generated dynamic image deformation as long as it is similar to real liquid deformations in its spatiotemporal frequency profile. Our findings indicate that the brain can perceptually infer the presence of "invisible" transparent liquids by analyzing the spatiotemporal structure of dynamic image deformation, for which it uses a relatively simple computation that does not require high-level knowledge about the detailed physics of liquid deformation.

Influence of detector noise and background noise on detection-system

NASA Astrophysics Data System (ADS)

Song, Yiheng; Wang, Zhiyong

2018-02-01

Study the noise by detectors and background light ,we find that the influence of background noise on the detection is more than that of itself. Therefore, base on the fiber coupled beam splitting technique, the small area detector is used to replace the large area detector. It can achieve high signal-to-noise ratio (SNR) and reduce the speckle interference of the background light. This technique is expected to solve the bottleneck of large field of view and high sensitivity.

Effects of background, direction and intensity of ambient light, measuring position, and adjacent teeth, on anterior tooth colour measurement in vitro.

PubMed

Ma, Jian Feng; Du, Ruo Xi; Wang, Si Qian; Li, Yi Ming

2010-01-01

to investigate the effects of different background colours (black, white or pink), direction and intensity of ambient light, measuring position, and the adjacent teeth, on the in vitro colour measurement of maxillary anterior teeth, using the Minolta CR-321 colorimeter. ten extracted human maxillary central incisors were selected. A fibre-optic light MI-150 was used as the ambient illuminant. Teeth were irradiated from a 3- or 12-o'clock direction. L*a*b* values of seven sites on the labial surfaces were obtained by means of the Minolta CR-321 colorimeter, using three background colours, with or without the adjacent teeth. The recorded data were analysed with two-tailed Student t tests and analysis of variance (α = 0.05). the ambient light did not affect the colour measurement of anterior teeth, regardless of the presence or absence of the adjacent teeth. There were no statistically significant differences in L*a*b* values at the same position under different background colours, except ΔE12 (colour difference between site 1 and site 2) between black and white backgrounds. ΔE12 (under black background), ΔE13 and ΔE15 were greater than 1.5, while the others were lower than 1.5. the background, ambient light and the presence of adjacent teeth did not affect the colour measurement of anterior teeth using the Minolta CR-321 colorimeter in vitro. The inherent disadvantages of using the naked eye during clinical visual shade assessment may be overcome by the colorimeter.

Functional Accumulation of Antenna Proteins in Chlorophyll b-Less Mutants of Chlamydomonas reinhardtii.

PubMed

Bujaldon, Sandrine; Kodama, Natsumi; Rappaport, Fabrice; Subramanyam, Rajagopal; de Vitry, Catherine; Takahashi, Yuichiro; Wollman, Francis-André

2017-01-09

The green alga Chlamydomonas reinhardtii contains several light-harvesting chlorophyll a/b complexes (LHC): four major LHCIIs, two minor LHCIIs, and nine LHCIs. We characterized three chlorophyll b-less mutants to assess the effect of chlorophyll b deficiency on the function, assembly, and stability of these chlorophyll a/b binding proteins. We identified point mutations in two mutants that inactivate the CAO gene responsible for chlorophyll a to chlorophyll b conversion. All LHCIIs accumulated to wild-type levels in a CAO mutant but their light-harvesting function for photosystem II was impaired. In contrast, most LHCIs accumulated to wild-type levels in the mutant and their light-harvesting capability for photosystem I remained unaltered. Unexpectedly, LHCI accumulation and the photosystem I functional antenna size increased in the mutant compared with in the wild type when grown in dim light. When the CAO mutation was placed in a yellow-in-the-dark background (yid-BF3), in which chlorophyll a synthesis remains limited in dim light, accumulation of the major LHCIIs and of most LHCIs was markedly reduced, indicating that sustained synthesis of chlorophyll a is required to preserve the proteolytic resistance of antenna proteins. Indeed, after crossing yid-BF3 with a mutant defective for the thylakoid FtsH protease activity, yid-BF3-ftsh1 restored wild-type levels of LHCI, which defines LHCI as a new substrate for the FtsH protease. Copyright © 2017 The Author. Published by Elsevier Inc. All rights reserved.

Development of an ultralow-light-level luminescence image analysis system for dynamic measurements of transcriptional activity in living and migrating cells.

PubMed

Maire, E; Lelièvre, E; Brau, D; Lyons, A; Woodward, M; Fafeur, V; Vandenbunder, B

2000-04-10

We have developed an approach to study in single living epithelial cells both cell migration and transcriptional activation, which was evidenced by the detection of luminescence emission from cells transfected with luciferase reporter vectors. The image acquisition chain consists of an epifluorescence inverted microscope, connected to an ultralow-light-level photon-counting camera and an image-acquisition card associated to specialized image analysis software running on a PC computer. Using a simple method based on a thin calibrated light source, the image acquisition chain has been optimized following comparisons of the performance of microscopy objectives and photon-counting cameras designed to observe luminescence. This setup allows us to measure by image analysis the luminescent light emitted by individual cells stably expressing a luciferase reporter vector. The sensitivity of the camera was adjusted to a high value, which required the use of a segmentation algorithm to eliminate the background noise. Following mathematical morphology treatments, kinetic changes of luminescent sources were analyzed and then correlated with the distance and speed of migration. Our results highlight the usefulness of our image acquisition chain and mathematical morphology software to quantify the kinetics of luminescence changes in migrating cells.

The faint galaxy contribution to the diffuse extragalactic background light

NASA Technical Reports Server (NTRS)

Cole, Shaun; Treyer, Marie-Agnes; Silk, Joseph

1992-01-01

Models of the faint galaxy contribution to the diffuse extragalactic background light are presented, which are consistent with current data on faint galaxy number counts and redshifts. The autocorrelation function of surface brightness fluctuations in the extragalactic diffuse light is predicted, and the way in which these predictions depend on the cosmological model and assumptions of biasing is determined. It is confirmed that the recent deep infrared number counts are most compatible with a high density universe (Omega-0 is approximately equal to 1) and that the steep blue counts then require an extra population of rapidly evolving blue galaxies. The faintest presently detectable galaxies produce an interesting contribution to the extragalactic diffuse light, and still fainter galaxies may also produce a significant contribution. These faint galaxies still only produce a small fraction of the total optical diffuse background light, but on scales of a few arcminutes to a few degrees, they produce a substantial fraction of the fluctuations in the diffuse light.

Stokes-Doppler coherence imaging for ITER boundary tomography.

PubMed

Howard, J; Kocan, M; Lisgo, S; Reichle, R

2016-11-01

An optical coherence imaging system is presently being designed for impurity transport studies and other applications on ITER. The wide variation in magnetic field strength and pitch angle (assumed known) across the field of view generates additional Zeeman-polarization-weighting information that can improve the reliability of tomographic reconstructions. Because background reflected light will be somewhat depolarized analysis of only the polarized fraction may be enough to provide a level of background suppression. We present the principles behind these ideas and some simulations that demonstrate how the approach might work on ITER. The views and opinions expressed herein do not necessarily reflect those of the ITER Organization.

Objectively assessed recess physical activity in girls and boys from high and low socioeconomic backgrounds.

PubMed

Baquet, Georges; Ridgers, Nicola D; Blaes, Aurélie; Aucouturier, Julien; Van Praagh, Emmanuel; Berthoin, Serge

2014-02-21

The school environment influences children's opportunities for physical activity participation. The aim of the present study was to assess objectively measured school recess physical activity in children from high and low socioeconomic backgrounds. Four hundred and seven children (6-11 years old) from 4 primary schools located in high socioeconomic status (high-SES) and low socioeconomic status (low-SES) areas participated in the study. Children's physical activity was measured using accelerometry during morning and afternoon recess during a 4-day school week. The percentage of time spent in light, moderate, vigorous, very high and in moderate- to very high-intensity physical activity were calculated using age-dependent cut-points. Sedentary time was defined as 100 counts per minute. Boys were significantly (p < 0.001) more active than girls. No difference in sedentary time between socioeconomic backgrounds was observed. The low-SES group spent significantly more time in light (p < 0.001) and very high (p < 0.05) intensity physical activity compared to the high-SES group. High-SES boys and girls spent significantly more time in moderate (p < 0.001 and p < 0.05, respectively) and vigorous (p < 0.001) physical activity than low-SES boys. Differences were observed in recess physical activity levels according to socioeconomic background and sex. These results indicate that recess interventions should target children in low-SES schools.

The nature of the near-infrared interline sky background using fibre Bragg grating OH suppression

NASA Astrophysics Data System (ADS)

Trinh, Christopher Q.; Ellis, Simon C.; Bland-Hawthorn, Joss; Horton, Anthony J.; Lawrence, Jon S.; Leon-Saval, Sergio G.

2013-07-01

We analyse the near-infrared interline sky background, OH and O2 emission in 19 h of H-band observations with the GNOSIS OH-suppression unit and the IRIS2 spectrograph at the 3.9-m Anglo-Australian Telescope. We find that the long-term behaviour of OH emission is best described by a gradual decrease during the first half of the night followed by a gradual increase during the second half of the night following the behaviour of the solar elevation angle. We measure the interline background at 1.520 μm where the instrumental thermal background is very low and study its variation with zenith distance, time after sunset, ecliptic latitude, lunar zenith distance and lunar distance to determine the presence of non-thermal atmospheric emission, zodiacal scattered light and scattered moonlight. Zodiacal scattered light is too faint to be detected in the summed observations. Scattered moonlight due to Mie scattering by atmospheric aerosols is seen at small lunar distances (ρ ≲ 11°), but is otherwise too faint to detect. Except at very small lunar distances the interline background at a resolving power of R ≈ 2400 when using OH-suppression fibres is dominated by a non-thermal atmospheric source with a temporal behaviour that resembles atmospheric OH emission, suggesting that the interline background contains instrumentally scattered OH. However, the interline background dims more rapidly than OH early in the night, suggesting contributions from rapid dimming molecules. The absolute interline background is 560 ± 120 photons s-1 m-2 μm- 1 arcsec-2 under dark conditions. This value is similar to previous measurements without OH suppression, suggesting that non-suppressed atmospheric emission is responsible for the interline background level. Future OH-suppression fibre designs may address this by the suppression of more sky lines using more accurate sky-line measurements taken from high-resolution spectra.

Active background suppression with the liquid argon scintillation veto of GERDA Phase II

NASA Astrophysics Data System (ADS)

Agostini, M.; Allardt, M.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Baudis, L.; Bauer, C.; Bellotti, E.; Belogurov, S.; Belyaev, S. T.; Benato, G.; Bettini, A.; Bezrukov, L.; Bode, T.; Borowicz, D.; Brudanin, V.; Brugnera, R.; Caldwell, A.; Cattadori, C.; Chernogorov, A.; D'Andrea, V.; Demidova, E. V.; Di Marco, N.; Domula, A.; Doroshkevich, E.; Egorov, V.; Falkenstein, R.; Frodyma, N.; Gangapshev, A.; Garfagnini, A.; Gooch, C.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Hakenmüller, J.; Hegai, A.; Heisel, M.; Hemmer, S.; Hofmann, W.; Hult, M.; Inzhechik, L. V.; Janicskó Csáthy, J.; Jochum, J.; Junker, M.; Kazalov, V.; Kihm, T.; Kirpichnikov, I. V.; Kirsch, A.; Kish, A.; Klimenko, A.; Kneißl, R.; Knöpfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kuzminov, V. V.; Laubenstein, M.; Lazzaro, A.; Lebedev, V. I.; Lehnert, B.; Liao, H. Y.; Lindner, M.; Lippi, I.; Lubashevskiy, A.; Lubsandorzhiev, B.; Lutter, G.; Macolino, C.; Majorovits, B.; Maneschg, W.; Medinaceli, E.; Miloradovic, M.; Mingazheva, R.; Misiaszek, M.; Moseev, P.; Nemchenok, I.; Palioselitis, D.; Panas, K.; Pandola, L.; Pelczar, K.; Pullia, A.; Riboldi, S.; Rumyantseva, N.; Sada, C.; Salamida, F.; Salathe, M.; Schmitt, C.; Schneider, B.; Schönert, S.; Schreiner, J.; Schulz, O.; Schütz, A.-K.; Schwingenheuer, B.; Selivanenko, O.; Shevzik, E.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Vanhoefer, L.; Vasenko, A. A.; Veresnikova, A.; von Sturm, K.; Wagner, V.; Wegmann, A.; Wester, T.; Wiesinger, C.; Wojcik, M.; Yanovich, E.; Zhitnikov, I.; Zhukov, S. V.; Zinatulina, D.; Zuber, K.; Zuzel, G.

2017-09-01

The observation of neutrinoless double beta decay would allow to shed light onto the particle nature of neutrinos. Gerda is aiming to perform a background-free search for this process using high purity germanium detectors enriched in 76Ge operated in liquid argon. This goal relies on the application of active background suppression techniques. A low background light instrumentation has been installed for Phase II to detect events with coincident energy deposition in the nearby liquid argon. The intended background index of ˜10-3 cts/(keV·ky·yr) has been confirmed.

Glutathione S-Transferase Pi Isoform (GSTP1) Expression in Murine Retina Increases with Developmental Maturity

PubMed Central

Lee, Wen-Hsiang; Joshi, Pratibha; Wen, Rong

2014-01-01

Background and Aims Glutathione S-transferase pi isoform (GSTP1) is an intracellular detoxification enzyme that catalyzes reduction of chemically reactive electrophiles and is a zeaxanthin-binding protein in the human macula. We have previously demonstrated that GSTP1 levels are decreased in human age-related macular degeneration (AMD) retina compared to normal controls [1]. We also showed that GSTP1 levels parallel survival of human retinal pigment epithelial (RPE) cells exposed to UV light, and GSTP1 over-expression protects them against UV light damage [2]. In the present work, we determined the developmental time course of GSTP1 expression in murine retina and in response to light challenge. Methods Eyes from BALB/c mice at post-natal day 20, 1 month, and 2 months of age were prepared for retinal protein extraction and cryo sectioning, and GSTP1 levels in the retina were analyzed by Western blot and immunohistochemistry (IHC). Another group of BALB/c mice with the same age ranges was exposed to 1000 lux of white fluorescent light for 24 hours, and their retinas were analyzed for GSTP1 expression by Western blot and IHC in a similar manner. Results GSTP1 levels in the murine retina increased in ascending order from post-natal day 20, 1 month, and 2 months of age. Moreover, GSTP1 expression in murine retina at post-natal day 20, 1 month, and 2 months of age increased in response to brief light exposure compared to age-matched controls under normal condition. Conclusions GSTP1 expression in retina increases with developmental age in mice and accompanies murine retinal maturation. Brief exposure to light induces GSTP1 expression in the murine retina across various developmental ages. GSTP1 induction may be a protective response to light-induced oxidative damage in the murine retina. PMID:24664677

Flame Imaging System

NASA Technical Reports Server (NTRS)

Barnes, Heidi L. (Inventor); Smith, Harvey S. (Inventor)

1998-01-01

A system for imaging a flame and the background scene is discussed. The flame imaging system consists of two charge-coupled-device (CCD) cameras. One camera uses a 800 nm long pass filter which during overcast conditions blocks sufficient background light so the hydrogen flame is brighter than the background light, and the second CCD camera uses a 1100 nm long pass filter, which blocks the solar background in full sunshine conditions such that the hydrogen flame is brighter than the solar background. Two electronic viewfinders convert the signal from the cameras into a visible image. The operator can select the appropriate filtered camera to use depending on the current light conditions. In addition, a narrow band pass filtered InGaAs sensor at 1360 nm triggers an audible alarm and a flashing LED if the sensor detects a flame, providing additional flame detection so the operator does not overlook a small flame.

Use of a Reflective Ultraviolet Imaging System (RUVIS) on Two-Dimensional Dust Impressions Created with Footwear on Multiple Substrates

NASA Astrophysics Data System (ADS)

Engelson, Brian Aaron

Footwear impression evidence in dust is often difficult to locate in ambient light and is a fragile medium that both collection and enhancement techniques can destroy or distort. The collection of footwear impression evidence always begins with non-destructive photographic techniques; however, current methods are limited to oblique lighting of the impression followed by an attempt to photograph in situ. For the vast majority of footwear impressions, an interactive collection method, and thus a potentially destructive procedure, is subsequently carried out to gather the evidence. Therefore, alternative non-destructive means for the preservation and enhancement of footwear impressions in dust merits further attention. Previous research performed with reflected ultraviolet (UV) photography and reflected ultraviolet imaging systems (RUVIS) has shown that there are additional non-destructive methodologies that can be applied to the search for and documentation of footwear impressions in dust. Unfortunately, these prior studies did not include robust comparisons to traditional oblique white light, instead choosing to focus on different UV wavelengths. This study, however, seeks to evaluate the use of a RUVIS device paired with a 254 nanometer (nm) UV light source to locate 2-D footwear impressions in dust on multiple substrates against standard oblique white light techniques and assess the visibility of the impression and amount of background interference present. The optimal angle of incident UV light for each substrate was also investigated. Finally, this study applied an image enhancement technique in order to evaluate its usefulness when looking at the visibility of a footwear impression and the amount of background interference present for enhanced white light and RUVIS pictures of footwear impressions in dust. A collection of eight different substrate types was gathered for investigation, including vinyl composition tile (VCT), ceramic tile, marble tile, magazine paper, steel sheet metal, vinyl flooring, wood flooring, and carpet. Heel impressions were applied to the various substrates utilizing vacuum collected dust and normal walking pressure. Each substrate was then explored and photographed in ambient fluorescent light, oblique white light at 0°, 15°, 30°, and 0° with the light source below the surface plane of the substrate, and 254 nm UV light at 0°, 15°, 30°, 45°, 60°, 75°, 90° and 0° with the light source below the surface plane of the substrate. All pictures were evaluated for clarity and visible detail of the footwear impression and the amount of background interference present, selecting for the best images within a lighting condition group. Additional intra- and intergroup comparisons were carried out to explore differences created by the various lighting conditions. Enhanced images were then created with the best scored pictures and evaluated for additional modifications in impression visibility and background interference. Photographs of footwear impressions in dust illuminated with ambient fluorescent light proved to be the most difficult conditions under which a footwear impression could be visualized. However, both oblique white light and 254 nm UV light lighting conditions showed improvements in either visualization or background dropout, or both, over ambient light conditions. An assessment of the white light and 254 nm UV light RUVIS images also demonstrated that the best angles for the light source for all substrates were oblique 0 and oblique 0° below the surface plane of the substrate lighting. It was found that white light photographs generally provided higher visibility ratings, while RUVIS 254 nm UV light photographs provided better grades for reducing background interference. Enhanced images of white light conditions provided generally poorer quality and quantity of details, while enhanced RUVIS images seemed to improve upon these areas. The use of a RUVIS to capture photographs of footwear impression evidence in dust was found to be a successful secondary non-destructive technique that can be paired with traditional oblique white light procedures. Additionally, the use of below the surface plane of the substrate lighting techniques were found to improve either visibility or background dropout, or both, over standard 0 oblique lighting, depending on the light source, and should be employed, when applicable. Finally, further investigation into digital photo-editing enhancement techniques for footwear impression evidence in dust is needed.

Formation of 2D bright spatial solitons in lithium niobate with photovoltaic response and incoherent background

NASA Astrophysics Data System (ADS)

Pustozerov, A.; Shandarov, V.

2017-12-01

The influence of incoherent background illumination produced by light-emitting diodes (LED's) of different average wavelengths and laser diode emitting in blue region of visible on diffraction characteristics of narrow coherent light beams of He-Ne laser due to refractive index changes of Fe-doped lithium niobate sample are studied. It has been experimentally demonstrated that nonlinear diffraction of red beams with wavelength 633 nm and diameters on full width of half maximum (FWHM) near to 15 μm may be totally compensated using background light with average wavelengths 450 - 465 nm. To provide the necessary intensity of incoherent background, the combinations of spherical and cylindrical concave lenses with blue LED and laser diode module without focusing its beam have been used.

Harnessing the Power of Light to See and Treat Breast Cancer

DTIC Science & Technology

2015-12-01

complexity : the raw data, the most basic form of data, represents the raw numeric readout obtained from the acquisition hardware. The raw data...has the added advantage of full-field illumination and non-descanned detection, thus lowering the complexity compared to confocal scanning systems... complexity of images that have varying levels of contrast and non-uniform background heterogeneity. In 2004 Matas described a technique for detecting

Study of Colour Model for Segmenting Mycobacterium Tuberculosis in Sputum Images

NASA Astrophysics Data System (ADS)

Kurniawardhani, A.; Kurniawan, R.; Muhimmah, I.; Kusumadewi, S.

2018-03-01

One of method to diagnose Tuberculosis (TB) disease is sputum test. The presence and number of Mycobacterium tuberculosis (MTB) in sputum are identified. The presence of MTB can be seen under light microscope. Before investigating through stained light microscope, the sputum samples are stained using Ziehl-Neelsen (ZN) stain technique. Because there is no standard procedure in staining, the appearance of sputum samples may vary either in background colour or contrast level. It increases the difficulty in segmentation stage of automatic MTB identification. Thus, this study investigated the colour models to look for colour channels of colour model that can segment MTB well in different stained conditions. The colour models will be investigated are each channel in RGB, HSV, CIELAB, YCbCr, and C-Y colour model and the clustering algorithm used is k-Means. The sputum image dataset used in this study is obtained from community health clinic in a district in Indonesia. The size of each image was set to 1600x1200 pixels which is having variation in number of MTB, background colour, and contrast level. The experiment result indicates that in all image conditions, blue, hue, Cr, and Ry colour channel can be used to segment MTB in one cluster well.

Research of spectacle frame measurement system based on structured light method

NASA Astrophysics Data System (ADS)

Guan, Dong; Chen, Xiaodong; Zhang, Xiuda; Yan, Huimin

2016-10-01

Automatic eyeglass lens edging system is now widely used to automatically cut and polish the uncut lens based on the spectacle frame shape data which is obtained from the spectacle frame measuring machine installed on the system. The conventional approach to acquire the frame shape data works in the contact scanning mode with a probe tracing around the groove contour of the spectacle frame which requires a sophisticated mechanical and numerical control system. In this paper, a novel non-contact optical measuring method based on structured light to measure the three dimensional (3D) data of the spectacle frame is proposed. First we focus on the processing approach solving the problem of deterioration of the structured light stripes caused by intense specular reflection on the frame surface. The techniques of bright-dark bi-level fringe projecting, multiple exposuring and high dynamic range imaging are introduced to obtain a high-quality image of structured light stripes. Then, the Gamma transform and median filtering are applied to enhance image contrast. In order to get rid of background noise from the image and extract the region of interest (ROI), an auxiliary lighting system of special design is utilized to help effectively distinguish between the object and the background. In addition, a morphological method with specific morphological structure-elements is adopted to remove noise between stripes and boundary of the spectacle frame. By further fringe center extraction and depth information acquisition through the method of look-up table, the 3D shape of the spectacle frame is recovered.

Systems analysis of the single photon response in invertebrate photoreceptors.

PubMed

Pumir, Alain; Graves, Jennifer; Ranganathan, Rama; Shraiman, Boris I

2008-07-29

Photoreceptors of Drosophila compound eye employ a G protein-mediated signaling pathway that transduces single photons into transient electrical responses called "quantum bumps" (QB). Although most of the molecular components of this pathway are already known, the system-level understanding of the mechanism of QB generation has remained elusive. Here, we present a quantitative model explaining how QBs emerge from stochastic nonlinear dynamics of the signaling cascade. The model shows that the cascade acts as an "integrate and fire" device and explains how photoreceptors achieve reliable responses to light although keeping low background in the dark. The model predicts the nontrivial behavior of mutants that enhance or suppress signaling and explains the dependence on external calcium, which controls feedback regulation. The results provide insight into physiological questions such as single-photon response efficiency and the adaptation of response to high incident-light level. The system-level analysis enabled by modeling phototransduction provides a foundation for understanding G protein signaling pathways less amenable to quantitative approaches.

Effects of Background Lighting Color and Movement Distance on Reaching Times Among Participants With Low Vision, Myopia, and Normal Vision.

PubMed

Chen, Chun-Fu; Huang, Kuo-Chen

2016-04-01

This study investigated the effects of target distance (30, 35, and 40 cm) and the color of background lighting (red, green, blue, and yellow) on the duration of movements made by participants with low vision, myopia, and normal vision while performing a reaching task; 48 students (21 women, 27 men; M age = 21.8 year, SD = 2.4) participated in the study. Participants reached for a target (a white LED light) whose vertical position varied randomly across trials, ranging in distance from 30 to 40 cm. Movement time was analyzed using a 3 (participant group) × [4 (color of background lighting) × 3 (movement distance)] mixed-design ANOVA model. Results indicated longer times for completing a reaching movement when: participants belonged to the low vision group; the target distance between the starting position and the target position was longer (40 cm); and the reaching movement occurred in the red-background lighting condition. These results are particularly relevant for situations in which a user is required to respond to a signal by reaching toward a button or an icon. © The Author(s) 2016.

Seedling Growth Strategies in Bauhinia Species: Comparing Lianas and Trees

PubMed Central

Cai, Zhi-Quan; Poorter, Lourens; Cao, Kun-Fang; Bongers, Frans

2007-01-01

Background and Aims Lianas are expected to differ from trees in their growth strategies. As a result these two groups of woody species will have different spatial distributions: lianas are more common in high light environments. This study determines the differences in growth patterns, biomass allocation and leaf traits in five closely related liana and tree species of the genus Bauhinia. Methods Seedlings of two light-demanding lianas (Bauhinia tenuiflora and B. claviflora), one shade-tolerant liana (B. aurea), and two light-demanding trees (B. purpurea and B. monandra) were grown in a shadehouse at 25 % of full sunlight. A range of physiological, morphological and biomass parameters at the leaf and whole plant level were compared among these five species. Key Results The two light-demanding liana species had higher relative growth rate (RGR), allocated more biomass to leaf production [higher leaf mass fraction (LMF) and higher leaf area ratio (LAR)] and stem mass fraction (SMF), and less biomass to the roots [root mass fraction (RMF)] than the two tree species. The shade-tolerant liana had the lowest RGR of all five species, and had a higher RMF, lower SMF and similar LMF than the two light-demanding liana species. The two light-demanding lianas had lower photosynthetic rates per unit area (Aarea) and similar photosynthetic rates per unit mass (Amass) than the trees. Across species, RGR was positively related to SLA, but not to LAR and Aarea. Conclusions It is concluded that the faster growth of light-demanding lianas compared with light-demanding trees is based on morphological parameters (SLA, LMF and LAR), and cannot be attributed to higher photosynthetic rates at the leaf level. The shade-tolerant liana exhibited a slow-growth strategy, compared with the light-demanding species. PMID:17720978

A new microscope optics for laser dark-field illumination applied to high precision two dimensional measurement of specimen displacement.

PubMed

Noda, Naoki; Kamimura, Shinji

2008-02-01

With conventional light microscopy, precision in the measurement of the displacement of a specimen depends on the signal-to-noise ratio when we measure the light intensity of magnified images. This implies that, for the improvement of precision, getting brighter images and reducing background light noise are both inevitably required. For this purpose, we developed a new optics for laser dark-field illumination. For the microscopy, we used a laser beam and a pair of axicons (conical lenses) to get an optimal condition for dark-field observations. The optics was applied to measuring two dimensional microbead displacements with subnanometer precision. The bandwidth of our detection system overall was 10 kHz. Over most of this bandwidth, the observed noise level was as small as 0.1 nm/radicalHz.

Enhancement of crop photosynthesis by diffuse light: quantifying the contributing factors

PubMed Central

Li, T.; Heuvelink, E.; Dueck, T. A.; Janse, J.; Gort, G.; Marcelis, L. F. M.

2014-01-01

Background and Aims Plants use diffuse light more efficiently than direct light. However, experimental comparisons between diffuse and direct light have been obscured by co-occurring differences in environmental conditions (e.g. light intensity). This study aims to analyse the factors that contribute to an increase in crop photosynthesis in diffuse light and to quantify their relative contribution under different levels of diffuseness at similar light intensities. The hypothesis is that the enhancement of crop photosynthesis in diffuse light results not only from the direct effects of more uniform vertical and horizontal light distribution in the crop canopy, but also from crop physiological and morphological acclimation. Methods Tomato (Solanum lycopersicum) crops were grown in three greenhouse compartments that were covered by glass with different degrees of light diffuseness (0, 45 and 71 % of the direct light being converted into diffuse light) while maintaining similar light transmission. Measurements of horizontal and vertical photosynthetic photon flux density (PPFD) distribution in the crop, leaf photosynthesis light response curves and leaf area index (LAI) were used to quantify each factor's contribution to an increase in crop photosynthesis in diffuse light. In addition, leaf temperature, photoinhibition, and leaf biochemical and anatomical properties were studied. Key Results The highest degree of light diffuseness (71 %) increased the calculated crop photosynthesis by 7·2 %. This effect was mainly attributed to a more uniform horizontal (33 % of the total effect) and vertical PPFD distribution (21 %) in the crop. In addition, plants acclimated to the high level of diffuseness by gaining a higher photosynthetic capacity of leaves in the middle of the crop and a higher LAI, which contributed 23 and 13 %, respectively, to the total increase in crop photosynthesis in diffuse light. Moreover, diffuse light resulted in lower leaf temperatures and less photoinhibition at the top of the canopy when global irradiance was high. Conclusions Diffuse light enhanced crop photosynthesis. A more uniform horizontal PPFD distribution played the most important role in this enhancement, and a more uniform vertical PPFD distribution and higher leaf photosynthetic capacity contributed more to the enhancement of crop photosynthesis than did higher values of LAI. PMID:24782436

Ultraviolet luminosity density of the universe during the epoch of reionization.

PubMed

Mitchell-Wynne, Ketron; Cooray, Asantha; Gong, Yan; Ashby, Matthew; Dolch, Timothy; Ferguson, Henry; Finkelstein, Steven; Grogin, Norman; Kocevski, Dale; Koekemoer, Anton; Primack, Joel; Smidt, Joseph

2015-09-08

The spatial fluctuations of the extragalactic background light trace the total emission from all stars and galaxies in the Universe. A multiwavelength study can be used to measure the integrated emission from first galaxies during reionization when the Universe was about 500 million years old. Here we report arcmin-scale spatial fluctuations in one of the deepest sky surveys with the Hubble Space Telescope in five wavebands between 0.6 and 1.6 μm. We model-fit the angular power spectra of intensity fluctuation measurements to find the ultraviolet luminosity density of galaxies at redshifts greater than 8 to be log ρ(UV) = 27.4(+0.2)(-1.2) ergs(-1) Hz(-1) Mpc(-3) (1σ). This level of integrated light emission allows for a significant surface density of fainter primeval galaxies that are below the point-source detection level in current surveys.

Image quality enhancement in low-light-level ghost imaging using modified compressive sensing method

NASA Astrophysics Data System (ADS)

Shi, Xiaohui; Huang, Xianwei; Nan, Suqin; Li, Hengxing; Bai, Yanfeng; Fu, Xiquan

2018-04-01

Detector noise has a significantly negative impact on ghost imaging at low light levels, especially for existing recovery algorithm. Based on the characteristics of the additive detector noise, a method named modified compressive sensing ghost imaging is proposed to reduce the background imposed by the randomly distributed detector noise at signal path. Experimental results show that, with an appropriate choice of threshold value, modified compressive sensing ghost imaging algorithm can dramatically enhance the contrast-to-noise ratio of the object reconstruction significantly compared with traditional ghost imaging and compressive sensing ghost imaging methods. The relationship between the contrast-to-noise ratio of the reconstruction image and the intensity ratio (namely, the average signal intensity to average noise intensity ratio) for the three reconstruction algorithms are also discussed. This noise suppression imaging technique will have great applications in remote-sensing and security areas.

Low hygroscopicity of ambient fresh carbonaceous aerosols from pyrotechnics smoke

DOE PAGES

Carrico, Christian M.; Gomez, Samantha Laray; Dubey, Manvendra Krishna; ...

2018-01-31

Pyrotechnics (fireworks) displays are common for many cultures worldwide, with Independence Day celebrations occurring annually on July 4th as the most notable in the U.S. Given an episodic nature, fireworks aerosol properties are poorly characterized. Here we report observations of optical properties of fresh smoke emissions from Independence Day fireworks smoke sampled at Los Alamos National Laboratory, New Mexico U.S.A. on 4–5 July 2016. Aerosol optical properties were measured with a photoacoustic extinctiometer (PAX, DMT, Inc., Model 870 nm) at low RH < 30% and a humidity controlled nephelometry system (Ecotech, Inc., 450 nm Aurora). ‘Dry’ light scattering coefficient (σsp)more » increased from background < 15 Mm –1 reaching 120 Mm –1 (450 nm) as a 2-min event peak, while the absorption coefficient increased from background of 0.5–4.4 Mm –1 (870 nm). The event peak occurred at 00:35 on 5 July 2016, ~3 h after local fireworks events, and decreased to background by 04:00 on 5 July 2016, showing well mixed aerosol properties. A notable result is that the aerosol hygroscopic response, as characterized by the ratio of wet to dry light scattering or f(RH = 85%), declined to 1.02 at the peak fireworks influence from a background ~1.7. Strong wavelength dependence of light scattering with Ångström exponent ~2.2 throughout the event showed a size distribution dominated by sub-micrometer particles. Likewise, single scattering albedo at 870 nm remained constant throughout the event with ω = 0.86 ± 0.03, indicating light absorbing carbon, though not dominant, was mixed with organic carbon. Subsequent laboratory testing with ground-level sparklers showed that pyrotechnics smoke can generate a strong hygroscopic response, however. As confirmed with chemical analysis, the chemistry of the fireworks was key to defining the hygroscopic response. As a result, sparkler smoke was dominated by salt species such as hygroscopic potassium chloride while it lacked the black powder explosives in aerial fireworks that contribute organic and elemental carbon to its non-hygroscopic smoke.« less

Low hygroscopicity of ambient fresh carbonaceous aerosols from pyrotechnics smoke

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

Carrico, Christian M.; Gomez, Samantha Laray; Dubey, Manvendra Krishna

Pyrotechnics (fireworks) displays are common for many cultures worldwide, with Independence Day celebrations occurring annually on July 4th as the most notable in the U.S. Given an episodic nature, fireworks aerosol properties are poorly characterized. Here we report observations of optical properties of fresh smoke emissions from Independence Day fireworks smoke sampled at Los Alamos National Laboratory, New Mexico U.S.A. on 4–5 July 2016. Aerosol optical properties were measured with a photoacoustic extinctiometer (PAX, DMT, Inc., Model 870 nm) at low RH < 30% and a humidity controlled nephelometry system (Ecotech, Inc., 450 nm Aurora). ‘Dry’ light scattering coefficient (σsp)more » increased from background < 15 Mm –1 reaching 120 Mm –1 (450 nm) as a 2-min event peak, while the absorption coefficient increased from background of 0.5–4.4 Mm –1 (870 nm). The event peak occurred at 00:35 on 5 July 2016, ~3 h after local fireworks events, and decreased to background by 04:00 on 5 July 2016, showing well mixed aerosol properties. A notable result is that the aerosol hygroscopic response, as characterized by the ratio of wet to dry light scattering or f(RH = 85%), declined to 1.02 at the peak fireworks influence from a background ~1.7. Strong wavelength dependence of light scattering with Ångström exponent ~2.2 throughout the event showed a size distribution dominated by sub-micrometer particles. Likewise, single scattering albedo at 870 nm remained constant throughout the event with ω = 0.86 ± 0.03, indicating light absorbing carbon, though not dominant, was mixed with organic carbon. Subsequent laboratory testing with ground-level sparklers showed that pyrotechnics smoke can generate a strong hygroscopic response, however. As confirmed with chemical analysis, the chemistry of the fireworks was key to defining the hygroscopic response. As a result, sparkler smoke was dominated by salt species such as hygroscopic potassium chloride while it lacked the black powder explosives in aerial fireworks that contribute organic and elemental carbon to its non-hygroscopic smoke.« less

Low hygroscopicity of ambient fresh carbonaceous aerosols from pyrotechnics smoke

NASA Astrophysics Data System (ADS)

Carrico, Christian M.; Gomez, Samantha L.; Dubey, Manvendra K.; Aiken, Allison C.

2018-04-01

Pyrotechnics (fireworks) displays are common for many cultures worldwide, with Independence Day celebrations occurring annually on July 4th as the most notable in the U.S. Given an episodic nature, fireworks aerosol properties are poorly characterized. Here we report observations of optical properties of fresh smoke emissions from Independence Day fireworks smoke sampled at Los Alamos National Laboratory, New Mexico U.S.A. on 4-5 July 2016. Aerosol optical properties were measured with a photoacoustic extinctiometer (PAX, DMT, Inc., Model 870 nm) at low RH < 30% and a humidity controlled nephelometry system (Ecotech, Inc., 450 nm Aurora). 'Dry' light scattering coefficient (σsp) increased from background < 15 Mm-1 reaching 120 Mm-1 (450 nm) as a 2-min event peak, while the absorption coefficient increased from background of 0.5-4.4 Mm-1 (870 nm). The event peak occurred at 00:35 on 5 July 2016, ∼3 h after local fireworks events, and decreased to background by 04:00 on 5 July 2016, showing well mixed aerosol properties. A notable result is that the aerosol hygroscopic response, as characterized by the ratio of wet to dry light scattering or f(RH = 85%), declined to 1.02 at the peak fireworks influence from a background ∼1.7. Strong wavelength dependence of light scattering with Ångström exponent ∼2.2 throughout the event showed a size distribution dominated by sub-micrometer particles. Likewise, single scattering albedo at 870 nm remained constant throughout the event with ω = 0.86 ± 0.03, indicating light absorbing carbon, though not dominant, was mixed with organic carbon. Subsequent laboratory testing with ground-level sparklers showed that pyrotechnics smoke can generate a strong hygroscopic response, however. As confirmed with chemical analysis, the chemistry of the fireworks was key to defining the hygroscopic response. Sparkler smoke was dominated by salt species such as hygroscopic potassium chloride while it lacked the black powder explosives in aerial fireworks that contribute organic and elemental carbon to its non-hygroscopic smoke.

Illumination-parameter adjustable and illumination-distribution visible LED helmet for low-level light therapy on brain injury

NASA Astrophysics Data System (ADS)

Wang, Pengbo; Gao, Yuan; Chen, Xiao; Li, Ting

2016-03-01

Low-level light therapy (LLLT) has been clinically applied. Recently, more and more cases are reported with positive therapeutic effect by using transcranial light emitting diodes (LEDs) illumination. Here, we developed a LLLT helmet for treating brain injuries based on LED arrays. We designed the LED arrays in circle shape and assembled them in multilayered 3D printed helmet with water-cooling module. The LED arrays can be adjust to touch the head of subjects. A control circuit was developed to drive and control the illumination of the LLLT helmet. The software portion provides the control of on and off of each LED arrays, the setup of illumination parameters, and 3D distribution of LLLT light dose in human subject according to the illumination setups. This LLLT light dose distribution was computed by a Monte Carlo model for voxelized media and the Visible Chinese Human head dataset and displayed in 3D view at the background of head anatomical structure. The performance of the whole system was fully tested. One stroke patient was recruited in the preliminary LLLT experiment and the following neuropsychological testing showed obvious improvement in memory and executive functioning. This clinical case suggested the potential of this Illumination-parameter adjustable and illuminationdistribution visible LED helmet as a reliable, noninvasive, and effective tool in treating brain injuries.

Low-Level Light Therapy with 410 nm Light Emitting Diode Suppresses Collagen Synthesis in Human Keloid Fibroblasts: An In Vitro Study

PubMed Central

Lee, Hyun Soo; Jung, Soo-Eun; Kim, Sue Kyung; Kim, You-Sun; Sohn, Seonghyang

2017-01-01

Background Keloids are characterized by excessive collagen deposition in the dermis, in which transforming growth factor β (TGF-β)/Smad signaling plays an important role. Low-level light therapy (LLLT) is reported as effective in preventing keloids in clinical reports, recently. To date, studies investigating the effect of LLLT on keloid fibroblasts are extremely rare. Objective We investigated the effect of LLLT with blue (410 nm), red (630 nm), and infrared (830 nm) light on the collagen synthesis in keloid fibroblasts. Methods Keloid fibroblasts were isolated from keloid-revision surgery samples and irradiated using 410-, 630-, 830-nm light emitting diode twice, with a 24-hour interval at 10 J/cm2. After irradiation, cells were incubated for 24 and 48 hours and real-time quantitative reverse transcription polymerase chain reaction was performed. Western blot analysis was also performed in 48 hours after last irradiation. The genes and proteins of collagen type I, TGF-β1, Smad3, and Smad7 were analyzed. Results We observed no statistically significant change in the viability of keloid fibroblasts after irradiation. Collagen type I was the only gene whose expression significantly decreased after irradiation at 410 nm when compared to the non-irradiated control. Western blot analysis showed that LLLT at 410 nm lowered the protein levels of collagen type I compared to the control. Conclusion LLLT at 410 nm decreased the expression of collagen type I in keloid fibroblasts and might be effective in preventing keloid formation in their initial stage. PMID:28392641

Post-PRK corneal scatter measurements with a scanning confocal slit photon counter

NASA Astrophysics Data System (ADS)

Taboada, John; Gaines, David; Perez, Mary A.; Waller, Steve G.; Ivan, Douglas J.; Baldwin, J. Bruce; LoRusso, Frank; Tutt, Ronald C.; Perez, Jose; Tredici, Thomas; Johnson, Dan A.

2000-06-01

Increased corneal light scatter or 'haze' has been associated with excimer laser photorefractive surgery of the cornea. The increased scatter can affect visual performance; however, topical steroid treatment post surgery substantially reduces the post PRK scatter. For the treatment and monitoring of the scattering characteristics of the cornea, various methods have been developed to objectively measure the magnitude of the scatter. These methods generally can measure scatter associated with clinically observable levels of haze. For patients with moderate to low PRK corrections receiving steroid treatment, measurement becomes fairly difficult as the haze clinical rating is non observable. The goal of this development was to realize an objective, non-invasive physical measurement that could produce a significant reading for any level including the background present in a normal cornea. As back-scatter is the only readily accessible observable, the instrument is based on this measurement. To achieve this end required the use of a confocal method to bias out the background light that would normally confound conventional methods. A number of subjects with nominal refractive errors in an Air Force study have undergone PRK surgery. A measurable increase in corneal scatter has been observed in these subjects whereas clinical ratings of the haze were noted as level zero. Other favorable aspects of this back-scatter based instrument include an optical capability to perform what is equivalent to an optical A-scan of the anterior chamber. Lens scatter can also be measured.

Quasimodo mediates daily and acute light effects on Drosophila clock neuron excitability.

PubMed

Buhl, Edgar; Bradlaugh, Adam; Ogueta, Maite; Chen, Ko-Fan; Stanewsky, Ralf; Hodge, James J L

2016-11-22

We have characterized a light-input pathway regulating Drosophila clock neuron excitability. The molecular clock drives rhythmic electrical excitability of clock neurons, and we show that the recently discovered light-input factor Quasimodo (Qsm) regulates this variation, presumably via an Na + , K + , Cl - cotransporter (NKCC) and the Shaw K + channel (dK V 3.1). Because of light-dependent degradation of the clock protein Timeless (Tim), constant illumination (LL) leads to a breakdown of molecular and behavioral rhythms. Both overexpression ( OX ) and knockdown ( RNAi ) of qsm, NKCC, or Shaw led to robust LL rhythmicity. Whole-cell recordings of the large ventral lateral neurons (l-LNv) showed that altering Qsm levels reduced the daily variation in neuronal activity: qsm OX led to a constitutive less active, night-like state, and qsm RNAi led to a more active, day-like state. Qsm also affected daily changes in K + currents and the GABA reversal potential, suggesting a role in modifying membrane currents and GABA responses in a daily fashion, potentially modulating light arousal and input to the clock. When directly challenged with blue light, wild-type l-LNvs responded with increased firing at night and no net response during the day, whereas altering Qsm, NKKC, or Shaw levels abolished these day/night differences. Finally, coexpression of Shaw OX and NKCC RNAi in a qsm mutant background restored LL-induced behavioral arrhythmicity and wild-type neuronal activity patterns, suggesting that the three genes operate in the same pathway. We propose that Qsm affects both daily and acute light effects in l-LNvs probably acting on Shaw and NKCC.

Quasimodo mediates daily and acute light effects on Drosophila clock neuron excitability

PubMed Central

Bradlaugh, Adam; Ogueta, Maite; Chen, Ko-Fan; Stanewsky, Ralf; Hodge, James J. L.

2016-01-01

We have characterized a light-input pathway regulating Drosophila clock neuron excitability. The molecular clock drives rhythmic electrical excitability of clock neurons, and we show that the recently discovered light-input factor Quasimodo (Qsm) regulates this variation, presumably via an Na+, K+, Cl− cotransporter (NKCC) and the Shaw K+ channel (dKV3.1). Because of light-dependent degradation of the clock protein Timeless (Tim), constant illumination (LL) leads to a breakdown of molecular and behavioral rhythms. Both overexpression (OX) and knockdown (RNAi) of qsm, NKCC, or Shaw led to robust LL rhythmicity. Whole-cell recordings of the large ventral lateral neurons (l-LNv) showed that altering Qsm levels reduced the daily variation in neuronal activity: qsmOX led to a constitutive less active, night-like state, and qsmRNAi led to a more active, day-like state. Qsm also affected daily changes in K+ currents and the GABA reversal potential, suggesting a role in modifying membrane currents and GABA responses in a daily fashion, potentially modulating light arousal and input to the clock. When directly challenged with blue light, wild-type l-LNvs responded with increased firing at night and no net response during the day, whereas altering Qsm, NKKC, or Shaw levels abolished these day/night differences. Finally, coexpression of ShawOX and NKCCRNAi in a qsm mutant background restored LL-induced behavioral arrhythmicity and wild-type neuronal activity patterns, suggesting that the three genes operate in the same pathway. We propose that Qsm affects both daily and acute light effects in l-LNvs probably acting on Shaw and NKCC. PMID:27821737

Iraqi adolescents: self-regard, self-derogation, and perceived threat in war.

PubMed

Carlton-Ford, Steve; Ender, Morten G; Tabatabai, Ahoo

2008-02-01

A year into the 2003 US-Iraq war, how were adolescents in Baghdad faring? Conflict-related events typically lower psychological well-being; in contrast, investment in and protection of threatened identities should lead to self-esteem striving and, presumably, better well-being. How threatened do Iraqi adolescents feel? Is their self-esteem related to their sense of threat? Do age, religion, ethnicity, and gender alter the link between perceived threat and self-esteem? We use data from 1000 randomly selected adolescents living in Baghdad during July 2004. Iraqi adolescents reported high levels of threat; those feeling more threatened reported higher levels of self-esteem. Social background correlates with both self-esteem and perceived threat, but controlling for social background does not eliminate the relationship between self-esteem and perceived threat. We interpret our results in light of theory and research concerning social identity, mortality threats, and war trauma.

High-contrast fluorescence imaging based on the polarization dependence of the fluorescence enhancement using an optical interference mirror slide.

PubMed

Yasuda, Mitsuru; Akimoto, Takuo

2015-01-01

High-contrast fluorescence imaging using an optical interference mirror (OIM) slide that enhances the fluorescence from a fluorophore located on top of the OIM surface is reported. To enhance the fluorescence and reduce the background light of the OIM, transverse-electric-polarized excitation light was used as incident light, and the transverse-magnetic-polarized fluorescence signal was detected. As a result, an approximate 100-fold improvement in the signal-to-noise ratio was achieved through a 13-fold enhancement of the fluorescence signal and an 8-fold reduction of the background light.

Design Criteria for Adaptive Roadway Lighting

DOT National Transportation Integrated Search

2014-07-01

This report provides the background and analysis used to develop criteria for the implementation of an adaptive lighting system for roadway lighting. Based on the analysis of crashes and lighting performance, a series of criteria and the associated d...

Double-layered liquid crystal light shutter for control of absorption and scattering of the light incident to a transparent display device

NASA Astrophysics Data System (ADS)

Huh, Jae-Won; Yu, Byeong-Hun; Shin, Dong-Myung; Yoon, Tae-Hoon

2015-03-01

Recently, a transparent display has got much attention as one of the next generation display devices. Especially, active studies on a transparent display using organic light-emitting diodes (OLEDs) are in progress. However, since it is not possible to obtain black color using a transparent OLED, it suffers from poor visibility. This inevitable problem can be solved by using a light shutter. Light shutter technology can be divided into two types; light absorption and scattering. However, a light shutter based on light absorption cannot block the background image perfectly and a light shutter based on light scattering cannot provide black color. In this work we demonstrate a light shutter using two liquid crystal (LC) layers, a light absorption layer and a light scattering layer. To realize a light absorption layer and a light scattering layer, we use the planar state of a dye-doped chiral nematic LC (CNLC) cell and the focal-conic state of a long-pitch CNLC cell, respectively. The proposed light shutter device can block the background image perfectly and show black color. We expect that the proposed light shutter can increase the visibility of a transparent display.

Searches for Light- and Heavy-flavor Three-jet Resonances in proton-proton Collisions with the CMS Detector at $$\\sqrt{s}$$ = 8 TeV

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

Seitz, Claudia

2014-01-01

A search for three-jet hadronic resonance production in proton-proton collisions at 8 TeV center-of-mass energy has been conducted by the CMS Collaboration at the LHC. The data set corresponds to an integrated luminosity of 19.4 fb -1. The search method is modelindependent. Events are selected that contain a large number of jets with high transverse momentum. An ensemble of jets is used to extract a new possible signal from copious QCD background. Event selection is optimized using a benchmark model where supersymmetric gluinos are pair-produced and each of the gluinos decays exclusively into three jets. Two scenarios of this decay are considered denoted by the RPV couplings λ'' 112 and λ'' 113 or λ'' 223. The first coupling allows for gluinos to decay into only light-flavor jets, while the latter two allow decays into one heavy-flavor and two light-flavor jets. No significant deviation is found between the selected events and the expected standard model multijet and tmore » $$\\bar{t}$$ background. For gluinos decaying through 00 112, masses below 650 GeV are excluded at the 95% confidence level. The search including heavy-flavor jets in the final state with the couplings λ'' 113 or λ'' 223 is the first of its kind. Gluinos decaying into one heavy-flavor and two light-flavor jets are excluded for masses between 200 and 835 GeV.« less

Multiple-channel ultra-violet absorbance detector for two-dimensional chromatographic separations.

PubMed

Lynch, Kyle B; Yang, Yu; Ren, Jiangtao; Liu, Shaorong

2018-05-01

In recent years, much research has gone into developing online comprehensive two-dimensional liquid chromatographic systems allowing for high peak capacities in comparable separation times to that of one-dimensional liquid chromatographic systems. However, the speed requirements in the second dimension (2nd-D) still remain one challenge for complex biological samples due to the current configuration of two column/two detector systems. Utilization of multiple 2nd-D columns can mitigate this challenge. To adapt this approach, we need a multiple channel detector. Here we develop a versatile multichannel ultraviolet (UV) light absorbance detector that is capable of simultaneously monitoring separations in 12 columns. The detector consists of a deuterium lighthouse, a flow cell assembly (a 13-channel flow cell fitted with a 13-photodiode-detection system), and a data acquisition and monitoring terminal. Through the use of a custom high optical quality furcated fiber to improve light transmission, precise machining of a flow cell to reduce background stray light through precision alignment, and sensitive electronic circuitry to reduce electronic noise through an active low pass filter, the background noise level is measured in the tens of µAU. We obtain a linear dynamic range of close to three orders of magnitude. Compared to a commercialized multichannel UV light absorbance detector like the Waters 2488 UV/Vis, our device provides an increase in channel detection while residing within the same noise region and linear range. Copyright © 2018 Elsevier B.V. All rights reserved.

Neuronal nonlinearity explains greater visual spatial resolution for darks than lights.

PubMed

Kremkow, Jens; Jin, Jianzhong; Komban, Stanley J; Wang, Yushi; Lashgari, Reza; Li, Xiaobing; Jansen, Michael; Zaidi, Qasim; Alonso, Jose-Manuel

2014-02-25

Astronomers and physicists noticed centuries ago that visual spatial resolution is higher for dark than light stimuli, but the neuronal mechanisms for this perceptual asymmetry remain unknown. Here we demonstrate that the asymmetry is caused by a neuronal nonlinearity in the early visual pathway. We show that neurons driven by darks (OFF neurons) increase their responses roughly linearly with luminance decrements, independent of the background luminance. However, neurons driven by lights (ON neurons) saturate their responses with small increases in luminance and need bright backgrounds to approach the linearity of OFF neurons. We show that, as a consequence of this difference in linearity, receptive fields are larger in ON than OFF thalamic neurons, and cortical neurons are more strongly driven by darks than lights at low spatial frequencies. This ON/OFF asymmetry in linearity could be demonstrated in the visual cortex of cats, monkeys, and humans and in the cat visual thalamus. Furthermore, in the cat visual thalamus, we show that the neuronal nonlinearity is present at the ON receptive field center of ON-center neurons and ON receptive field surround of OFF-center neurons, suggesting an origin at the level of the photoreceptor. These results demonstrate a fundamental difference in visual processing between ON and OFF channels and reveal a competitive advantage for OFF neurons over ON neurons at low spatial frequencies, which could be important during cortical development when retinal images are blurred by immature optics in infant eyes.

Single objective light-sheet microscopy for high-speed whole-cell 3D super-resolution

PubMed Central

Meddens, Marjolein B. M.; Liu, Sheng; Finnegan, Patrick S.; Edwards, Thayne L.; James, Conrad D.; Lidke, Keith A.

2016-01-01

We have developed a method for performing light-sheet microscopy with a single high numerical aperture lens by integrating reflective side walls into a microfluidic chip. These 45° side walls generate light-sheet illumination by reflecting a vertical light-sheet into the focal plane of the objective. Light-sheet illumination of cells loaded in the channels increases image quality in diffraction limited imaging via reduction of out-of-focus background light. Single molecule super-resolution is also improved by the decreased background resulting in better localization precision and decreased photo-bleaching, leading to more accepted localizations overall and higher quality images. Moreover, 2D and 3D single molecule super-resolution data can be acquired faster by taking advantage of the increased illumination intensities as compared to wide field, in the focused light-sheet. PMID:27375939

14 CFR 25.812 - Emergency lighting.

Code of Federal Regulations, 2011 CFR

2011-01-01

... sign required by § 25.811(d)(3) must have red letters at least 11/2 inches high on a white background... red letters at least 1 inch high on a white background at least 2 inches high. These signs may be... marking and locating signs, sources of general cabin illumination, interior lighting in emergency exit...

14 CFR 25.812 - Emergency lighting.

Code of Federal Regulations, 2010 CFR

2010-01-01

... sign required by § 25.811(d)(3) must have red letters at least 11/2 inches high on a white background... red letters at least 1 inch high on a white background at least 2 inches high. These signs may be... marking and locating signs, sources of general cabin illumination, interior lighting in emergency exit...

46 CFR 69.177 - Markings.

Code of Federal Regulations, 2014 CFR

2014-10-01

... part of the load line grid: (i) Vessels assigned only one gross and one net tonnage under § 69.175(c... mark. A vessel assigned two gross and two net tonnages which has more than one deck and no load line... in either a light color on a dark background or a dark color on a light background. ...

46 CFR 69.177 - Markings.

Code of Federal Regulations, 2011 CFR

2011-10-01

... part of the load line grid: (i) Vessels assigned only one gross and one net tonnage under § 69.175(c... mark. A vessel assigned two gross and two net tonnages which has more than one deck and no load line... in either a light color on a dark background or a dark color on a light background. ...

46 CFR 69.177 - Markings.

Code of Federal Regulations, 2013 CFR

2013-10-01

... part of the load line grid: (i) Vessels assigned only one gross and one net tonnage under § 69.175(c... mark. A vessel assigned two gross and two net tonnages which has more than one deck and no load line... in either a light color on a dark background or a dark color on a light background. ...

46 CFR 69.177 - Markings.

Code of Federal Regulations, 2012 CFR

2012-10-01

... part of the load line grid: (i) Vessels assigned only one gross and one net tonnage under § 69.175(c... mark. A vessel assigned two gross and two net tonnages which has more than one deck and no load line... in either a light color on a dark background or a dark color on a light background. ...

The LUCIFER Project: Achievements and Near Future Prospects

NASA Astrophysics Data System (ADS)

Beeman, J. W.; Bellini, F.; Benetti, P.; Cardani, L.; Casali, N.; Chiesa, D.; Clemenza, M.; Dafinei, I.; Di Domizio, S.; Ferroni, F.; Gironi, L.; Giuliani, A.; Gotti, C.; Maino, M.; Nagorny, S. S.; Nisi, S.; Nones, C.; Pagnanini, L.; Pattavina, L.; Pessina, G.; Piperno, G.; Pirro, S.; Previtali, E.; Rusconi, C.; Schäffner, K.; Tomei, C.; Vignati, M.

2016-08-01

In the view of exploring the inverted hierarchy region future experiments investigating the neutrinoless double beta decay have to demand for detectors with excellent energy resolution and zero background in the energy region of interest. Cryogenic scintillating bolometers are very suitable detectors for this task since they provide particle discrimination: the simultaneous detection of the phonon and light signal allows us to identify the interacting type of particle and thus guarantees a suppression of α -induced backgrounds, the key-issue for next-generation tonne-scale bolometric experiments. The LUCIFER project aims at running the first array of enriched scintillating Zn^{ {82}}Se bolometers (total mass of about 8kg of ^{ {82}}Se) with a background level as low as 10^{ {-3}} counts/(keV kg y) in the energy region of interest. The main effort is currently focused on the finalization of the crystal growth procedure in order to achieve high quality Zn^{ {82}}Se crystals both in terms of radiopurity and bolometric properties. We present results from tests of such crystals operated at mK temperatures which demonstrate the excellent background rejection capabilities of this detection approach towards a background-free demonstrator experiment. Besides, the high purity of the enriched ^{ {82}}Se material allows us to establish the most stringent limits on the half-life of the double beta decay of ^{ {82}}Se on excited levels.

Brace related stress in scoliosis patients – Comparison of different concepts of bracing

PubMed Central

Weiss, Hans-Rudolf; Werkmann, Mario; Stephan, Carola

2007-01-01

Background The BSSQbrace questionnaire has been shown to be reliable with good internal consistency and reproducibility estimating the stress scoliosis patients have whilst wearing their brace. Eight questions are provided focussing on this topic. A max. score of 24 can be achieved (from 0 for most stress to 24 for no stress). The subdivision of the score values is: 0–8 (strong stress), 9–16 (medium stress) and 17–24 (little stress). Study design Two BSSQbrace questionnaires have been posted to 65 patients under brace treatment from our Cheneau light data base. All patients had another kind of brace prior to the Cheneau light. The patients have been asked to rate their stress level using one questionnaire for the current brace and the other for the previous one. Results 63 Patients (59 girls and 4 boys) returned their fully completed questionnaires (average age 13,6 years, average Cobb angle 43,7 degrees). Stress level in the previous brace was 11,04 and in the Cheneau light(r) 13,87. The differences were highly significant in the t-test; t = -4,67; p < 0,001. Conclusion The use of the Cheneau light® brace leads to reduced stress and/or impairment for the patients under treatment compared to heavier brace models used so far. PMID:17708766

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

Meddens, Marjolein B. M.; Liu, Sheng; Finnegan, Patrick S.

Here, we have developed a method for performing light-sheet microscopy with a single high numerical aperture lens by integrating reflective side walls into a microfluidic chip. These 45° side walls generate light-sheet illumination by reflecting a vertical light-sheet into the focal plane of the objective. Light-sheet illumination of cells loaded in the channels increases image quality in diffraction limited imaging via reduction of out-of-focus background light. Single molecule super-resolution is also improved by the decreased background resulting in better localization precision and decreased photo-bleaching, leading to more accepted localizations overall and higher quality images. Moreover, 2D and 3D single moleculemore » super-resolution data can be acquired faster by taking advantage of the increased illumination intensities as compared to wide field, in the focused light-sheet.« less

Quantification of birefringence readily measures the level of muscle damage in zebrafish

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

Berger, Joachim, E-mail: Joachim.Berger@Monash.edu; Sztal, Tamar; Currie, Peter D.

2012-07-13

Highlights: Black-Right-Pointing-Pointer Report of an unbiased quantification of the birefringence of muscle of fish larvae. Black-Right-Pointing-Pointer Quantification method readily identifies level of overall muscle damage. Black-Right-Pointing-Pointer Compare zebrafish muscle mutants for level of phenotype severity. Black-Right-Pointing-Pointer Proposed tool to survey treatments that aim to ameliorate muscular dystrophy. -- Abstract: Muscular dystrophies are a group of genetic disorders that progressively weaken and degenerate muscle. Many zebrafish models for human muscular dystrophies have been generated and analysed, including dystrophin-deficient zebrafish mutants dmd that model Duchenne Muscular Dystrophy. Under polarised light the zebrafish muscle can be detected as a bright area in anmore » otherwise dark background. This light effect, called birefringence, results from the diffraction of polarised light through the pseudo-crystalline array of the muscle sarcomeres. Muscle damage, as seen in zebrafish models for muscular dystrophies, can readily be detected by a reduction in the birefringence. Therefore, birefringence is a very sensitive indicator of overall muscle integrity within larval zebrafish. Unbiased documentation of the birefringence followed by densitometric measurement enables the quantification of the birefringence of zebrafish larvae. Thereby, the overall level of muscle integrity can be detected, allowing the identification and categorisation of zebrafish muscle mutants. In addition, we propose that the establish protocol can be used to analyse treatments aimed at ameliorating dystrophic zebrafish models.« less

Preliminary evidence of cannabinoid effects on brain-derived neurotrophic factor (BDNF) levels in humans

PubMed Central

D’Souza, Deepak Cyril; Pittman, Brian; Perry, Edward; Simen, Arthur

2009-01-01

Background Acute and chronic exposure to cannabinoids has been associated with cognitive deficits, a higher risk for schizophrenia and other drug abuse. However, the precise mechanism underlying such effects is not known. Preclinical studies suggest that cannabinoids modulate brain-derived neurotrophic factor (BDNF). Accordingly, we hypothesized that Δ9-tetrahydrocannabinol (Δ9-THC), the principal active component of cannabis, would alter BDNF levels in humans. Materials and methods Healthy control subjects (n=14) and light users of cannabis (n=9) received intravenous administration of (0.0286 mg/kg) Δ9-THC in a double-blind, fixed order, placebo-controlled, laboratory study. Serum sampled at baseline, after placebo administration, and after Δ9-THC administration was assayed for BDNF using ELISA. Results Δ9-THC increased serum BDNF levels in healthy controls but not light users of cannabis. Further, light users of cannabis had lower basal BDNF levels. Δ9-THC produced psychotomimetic effects, perceptual alterations, and “high” and spatial memory impairments. Implications The effects of socially relevant doses of cannabinoids on BDNF suggest a possible mechanism underlying the consequences of exposure to cannabis. This may be of particular importance for the developing brain and also in disorders believed to involve altered neurodevelopment such as schizophrenia. Larger studies to investigate the effects of cannabinoids on BDNF and other neurotrophins are warranted. PMID:18807247

Research on photodiode detector-based spatial transient light detection and processing system

NASA Astrophysics Data System (ADS)

Liu, Meiying; Wang, Hu; Liu, Yang; Zhao, Hui; Nan, Meng

2016-10-01

In order to realize real-time signal identification and processing of spatial transient light, the features and the energy of the captured target light signal are first described and quantitatively calculated. Considering that the transient light signal has random occurrence, a short duration and an evident beginning and ending, a photodiode detector based spatial transient light detection and processing system is proposed and designed in this paper. This system has a large field of view and is used to realize non-imaging energy detection of random, transient and weak point target under complex background of spatial environment. Weak signal extraction under strong background is difficult. In this paper, considering that the background signal changes slowly and the target signal changes quickly, filter is adopted for signal's background subtraction. A variable speed sampling is realized by the way of sampling data points with a gradually increased interval. The two dilemmas that real-time processing of large amount of data and power consumption required by the large amount of data needed to be stored are solved. The test results with self-made simulative signal demonstrate the effectiveness of the design scheme. The practical system could be operated reliably. The detection and processing of the target signal under the strong sunlight background was realized. The results indicate that the system can realize real-time detection of target signal's characteristic waveform and monitor the system working parameters. The prototype design could be used in a variety of engineering applications.

The effect of background galaxy contamination on the absolute magnitude and light curve speed class of type Ia supernovae

NASA Technical Reports Server (NTRS)

Boisseau, John R.; Wheeler, J. Craig

1991-01-01

Observational data are presented in support of the hypothesis that background galaxy contamination is present in the photometric data of Ia supernovae and that this effect can account for the observed dispersion in the light curve speeds of most of Ia supernovae. The implication is that the observed dispersion in beta is artificial and that most of Ia supernovae have nearly homogeneous light curves. The result supports the notion that Ia supernovae are good standard candles.

Multiple wavelength spectral system simulating background light noise environment in satellite laser communications

NASA Astrophysics Data System (ADS)

Lu, Wei; Sun, Jianfeng; Hou, Peipei; Xu, Qian; Xi, Yueli; Zhou, Yu; Zhu, Funan; Liu, Liren

2017-08-01

Performance of satellite laser communications between GEO and LEO satellites can be influenced by background light noise appeared in the field of view due to sunlight or planets and some comets. Such influences should be studied on the ground testing platform before the space application. In this paper, we introduce a simulator that can simulate the real case of background light noise in space environment during the data talking via laser beam between two lonely satellites. This simulator can not only simulate the effect of multi-wavelength spectrum, but also the effects of adjustable angles of field-of-view, large range of adjustable optical power and adjustable deflection speeds of light noise in space environment. We integrate these functions into a device with small and compact size for easily mobile use. Software control function is also achieved via personal computer to adjust these functions arbitrarily. Keywords:

Stray light lessons learned from the Mars reconnaissance orbiter's optical navigation camera

NASA Astrophysics Data System (ADS)

Lowman, Andrew E.; Stauder, John L.

2004-10-01

The Optical Navigation Camera (ONC) is a technical demonstration slated to fly on NASA"s Mars Reconnaissance Orbiter in 2005. Conventional navigation methods have reduced accuracy in the days immediately preceding Mars orbit insertion. The resulting uncertainty in spacecraft location limits rover landing sites to relatively safe areas, away from interesting features that may harbor clues to past life on the planet. The ONC will provide accurate navigation on approach for future missions by measuring the locations of the satellites of Mars relative to background stars. Because Mars will be a bright extended object just outside the camera"s field of view, stray light control at small angles is essential. The ONC optomechanical design was analyzed by stray light experts and appropriate baffles were implemented. However, stray light testing revealed significantly higher levels of light than expected at the most critical angles. The primary error source proved to be the interface between ground glass surfaces (and the paint that had been applied to them) and the polished surfaces of the lenses. This paper will describe troubleshooting and correction of the problem, as well as other lessons learned that affected stray light performance.

Temperate rain forest species partition fine-scale gradients in light availability based on their leaf mass per area (LMA)

PubMed Central

Fajardo, Alex; Siefert, Andrew

2016-01-01

Background and Aims Ecologists are increasingly using plant functional traits to predict community assembly, but few studies have linked functional traits to species’ responses to fine-scale resource gradients. In this study, it was tested whether saplings of woody species partition fine-scale gradients in light availability based on their leaf mass per area (LMA) in three temperate rain forests and one Mediterranean forest in southern Chile. Methods LMA was measured under field conditions of all woody species contained in approx. 60 plots of 2 m2 in each site, and light availability, computed as the gap light index (GLI), was determined. For each site, species’ pairwise differences in mean LMA (Δ LMA) and abundance-weighted mean GLI (Δ light response) of 2 m2 plots were calculated and it was tested whether they were positively related using Mantel tests, i.e. if species with different LMA values differed in their response to light availability. Additionally linear models were fitted to the relationship between plot-level mean LMA and GLI across plots for each site. Key Results A positive and significant relationship was found between species’ pairwise differences in mean LMA and differences in light response across species for all temperate rain forests, but not for the Mediterranean forest. The results also indicated a significant positive interspecific link between LMA and light availability for all forests. This is in contrast to what is traditionally reported and to expectations from the leaf economics spectrum. Conclusions In environments subjected to light limitation, interspecific differences in a leaf trait (LMA) can explain the fine-scale partitioning of light availability gradients by woody plant species. This niche partitioning potentially facilitates species coexistence at the within-community level. The high frequency of evergreen shade-intolerant species in these forests may explain the positive correlation between light availability and LMA. PMID:27604280

Predicted distribution of visible and near-infrared radiant flux above and below a transmittant leaf

NASA Technical Reports Server (NTRS)

Roberts, Dar A.; Adams, John B.; Smith, Milton O.

1990-01-01

The effects are studied analytically of leaf size, leaf height, and background reflectance on the upward and downward radiant flux (RF) of a leaf. The leaf is horizontal and isotropically scattering in the computer model which examines the light environment in three regions about the leaf. The spectral properties of the leaf are based on measurements of the big-leaf maple, and the model is interpreted in terms of relative RF which is defined as a percentage of the total light in the model. The results demonstrate the dependence of upward relative RF on the light's wavelength and background reflectance with large variations in the NIR. Brightness varies directly with distance from background with maximum brightness achieved at lower heights for smaller leaves. These and other results suggest that NIR canopy reflectance due to leaves is highly dependent on the background reflectance.

LArGe: active background suppression using argon scintillation for the Gerda 0ν β β -experiment

NASA Astrophysics Data System (ADS)

Agostini, M.; Barnabé-Heider, M.; Budjáš, D.; Cattadori, C.; Gangapshev, A.; Gusev, K.; Heisel, M.; Junker, M.; Klimenko, A.; Lubashevskiy, A.; Pelczar, K.; Schönert, S.; Smolnikov, A.; Zuzel, G.

2015-10-01

LArGe is a Gerda low-background test facility to study novel background suppression methods in a low-background environment, for future application in the Gerda experiment. Similar to Gerda, LArGe operates bare germanium detectors submersed into liquid argon (1 m^3, 1.4 tons), which in addition is instrumented with photomultipliers to detect argon scintillation light. The scintillation signals are used in anti-coincidence with the germanium detectors to effectively suppress background events that deposit energy in the liquid argon. The background suppression efficiency was studied in combination with a pulse shape discrimination (PSD) technique using a BEGe detector for various sources, which represent characteristic backgrounds to Gerda. Suppression factors of a few times 10^3 have been achieved. First background data of LArGe with a coaxial HPGe detector (without PSD) yield a background index of (0.12-4.6)× 10^{-2} cts/(keV kg year) (90 % C.L.), which is at the level of Gerda Phase I. Furthermore, for the first time we monitor the natural ^{42}Ar abundance (parallel to Gerda), and have indication for the 2ν β β -decay in natural germanium. These results show the effectivity of an active liquid argon veto in an ultra-low background environment. As a consequence, the implementation of a liquid argon veto in Gerda Phase II is pursued.

Single objective light-sheet microscopy for high-speed whole-cell 3D super-resolution

DOE PAGES

Meddens, Marjolein B. M.; Liu, Sheng; Finnegan, Patrick S.; ...

2016-01-01

Here, we have developed a method for performing light-sheet microscopy with a single high numerical aperture lens by integrating reflective side walls into a microfluidic chip. These 45° side walls generate light-sheet illumination by reflecting a vertical light-sheet into the focal plane of the objective. Light-sheet illumination of cells loaded in the channels increases image quality in diffraction limited imaging via reduction of out-of-focus background light. Single molecule super-resolution is also improved by the decreased background resulting in better localization precision and decreased photo-bleaching, leading to more accepted localizations overall and higher quality images. Moreover, 2D and 3D single moleculemore » super-resolution data can be acquired faster by taking advantage of the increased illumination intensities as compared to wide field, in the focused light-sheet.« less

Scintillation light detectors with Neganov Luke amplification

NASA Astrophysics Data System (ADS)

Isaila, C.; Boslau, O.; Coppi, C.; Feilitzsch, F. v.; Goldstraß, P.; Jagemann, T.; Jochum, J.; Kemmer, J.; Lachenmaier, T.; Lanfranchi, J.-C.; Pahlke, A.; Potzel, W.; Rau, W.; Stark, M.; Wernicke, D.; Westphal, W.

2006-04-01

For an active suppression of the gamma and electron background in the Cryogenic Rare Event Search with Superconducting Thermometers (CRESST) dark matter experiment both phonons and scintillation light generated in a CaWO 4 crystal are detected simultaneously. The phonon signal is read out by a transition edge sensor (TES) on the CaWO 4 crystal. For light detection a silicon absorber equipped with a TES is employed. An efficient background discrimination requires very sensitive light detectors. The threshold can be improved by applying an electric field to the silicon crystal leading to an amplification of the thermal signal due to the Neganov-Luke effect. Measurements showing the improved sensitivity of the light detectors as well as future steps for reducing the observed extra noise will be presented.

Influence of background/surrounding area on accuracy of visual color matching.

PubMed

Dudea, Diana; Gasparik, Cristina; Botos, Alexandra; Alb, Florin; Irimie, Ada; Paravina, Rade D

2016-07-01

Visual shade selection is subjective and influenced by factors that might be operator-dependent or not. The objective was to evaluate influence of observer nonrelated factors (background/surrounding area, and light) and observer-related factors (gender and color competence) on shade-matching quality and to identify the most often mismatched shades in correlation with the background. Ten observers with average or superior color discrimination competence according to ISO TR 28642:2011 were asked to match 48 shade tabs of three VITA Classical shade guides, in a viewing booth under two light sources: D65 and D50. Gray, white, black, red, and light blue background/surrounding area simulated various clinical situations. The results were statistically analyzed using Kruskal-Wallis test and Mann-Whitney U test. Post hoc power analyses and sample size calculations were also conducted. The matching scores ranged between 72.7 % (using blue background) and 85.9 % (using white and black backgrounds). There was a statistically significant difference between matching scores on the five backgrounds (χ (2)(4) = 12.67, p = 0.01). When neutral gray was used as reference, Mann-Whitney U value was statistically significant only for the blue background (U = 107.00, Z = -2.52, p = 0.01). The influence of gender and lighting condition was also assessed, no statistically significance being found, but in both cases, the effect size and the achieved power were small. However, color discrimination competence did influence the results (p < 0.01). Background influenced shade matching results for tabs A3, B3, B4, and D4. Within the limitations of this study, it was concluded that 1. When it comes to the influence of the background/surround area on quality of color matching, no difference among achromatic backgrounds was recorded. Significantly worse results were recorded when the blue background was used. 2. Observers with superior color matching competence performed significantly better than the ones with average competence 3. The most frequently mismatched shade tabs were A3.5, B3, B4, and D4.

VNIR hyperspectral background characterization methods in adverse weather conditions

NASA Astrophysics Data System (ADS)

Romano, João M.; Rosario, Dalton; Roth, Luz

2009-05-01

Hyperspectral technology is currently being used by the military to detect regions of interest where potential targets may be located. Weather variability, however, may affect the ability for an algorithm to discriminate possible targets from background clutter. Nonetheless, different background characterization approaches may facilitate the ability for an algorithm to discriminate potential targets over a variety of weather conditions. In a previous paper, we introduced a new autonomous target size invariant background characterization process, the Autonomous Background Characterization (ABC) or also known as the Parallel Random Sampling (PRS) method, features a random sampling stage, a parallel process to mitigate the inclusion by chance of target samples into clutter background classes during random sampling; and a fusion of results at the end. In this paper, we will demonstrate how different background characterization approaches are able to improve performance of algorithms over a variety of challenging weather conditions. By using the Mahalanobis distance as the standard algorithm for this study, we compare the performance of different characterization methods such as: the global information, 2 stage global information, and our proposed method, ABC, using data that was collected under a variety of adverse weather conditions. For this study, we used ARDEC's Hyperspectral VNIR Adverse Weather data collection comprised of heavy, light, and transitional fog, light and heavy rain, and low light conditions.

The Cosmic Infrared Background Experiment (CIBER): A Sounding Rocket Payload to Study the near Infrared Extragalactic Background Light

NASA Astrophysics Data System (ADS)

Zemcov, M.; Arai, T.; Battle, J.; Bock, J.; Cooray, A.; Hristov, V.; Keating, B.; Kim, M. G.; Lee, D. H.; Levenson, L. R.; Mason, P.; Matsumoto, T.; Matsuura, S.; Nam, U. W.; Renbarger, T.; Sullivan, I.; Suzuki, K.; Tsumura, K.; Wada, T.

2013-08-01

The Cosmic Infrared Background Experiment (CIBER) is a suite of four instruments designed to study the near infrared (IR) background light from above the Earth's atmosphere. The instrument package comprises two imaging telescopes designed to characterize spatial anisotropy in the extragalactic IR background caused by cosmological structure during the epoch of reionization, a low resolution spectrometer to measure the absolute spectrum of the extragalactic IR background, and a narrow band spectrometer optimized to measure the absolute brightness of the zodiacal light foreground. In this paper we describe the design and characterization of the CIBER payload. The detailed mechanical, cryogenic, and electrical design of the system are presented, including all system components common to the four instruments. We present the methods and equipment used to characterize the instruments before and after flight, and give a detailed description of CIBER's flight profile and configurations. CIBER is designed to be recoverable and has flown four times, with modifications to the payload having been informed by analysis of the first flight data. All four instruments performed to specifications during the subsequent flights, and the scientific data from these flights are currently being analyzed.

THE COSMIC INFRARED BACKGROUND EXPERIMENT (CIBER): A SOUNDING ROCKET PAYLOAD TO STUDY THE NEAR INFRARED EXTRAGALACTIC BACKGROUND LIGHT

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

Zemcov, M.; Bock, J.; Hristov, V.

2013-08-15

The Cosmic Infrared Background Experiment (CIBER) is a suite of four instruments designed to study the near infrared (IR) background light from above the Earth's atmosphere. The instrument package comprises two imaging telescopes designed to characterize spatial anisotropy in the extragalactic IR background caused by cosmological structure during the epoch of reionization, a low resolution spectrometer to measure the absolute spectrum of the extragalactic IR background, and a narrow band spectrometer optimized to measure the absolute brightness of the zodiacal light foreground. In this paper we describe the design and characterization of the CIBER payload. The detailed mechanical, cryogenic, andmore » electrical design of the system are presented, including all system components common to the four instruments. We present the methods and equipment used to characterize the instruments before and after flight, and give a detailed description of CIBER's flight profile and configurations. CIBER is designed to be recoverable and has flown four times, with modifications to the payload having been informed by analysis of the first flight data. All four instruments performed to specifications during the subsequent flights, and the scientific data from these flights are currently being analyzed.« less

Influence of background size, luminance and eccentricity on different adaptation mechanisms

PubMed Central

Gloriani, Alejandro H.; Matesanz, Beatriz M.; Barrionuevo, Pablo A.; Arranz, Isabel; Issolio, Luis; Mar, Santiago; Aparicio, Juan A.

2016-01-01

Mechanisms of light adaptation have been traditionally explained with reference to psychophysical experimentation. However, the neural substrata involved in those mechanisms remain to be elucidated. Our study analyzed links between psychophysical measurements and retinal physiological evidence with consideration for the phenomena of rod-cone interactions, photon noise, and spatial summation. Threshold test luminances were obtained with steady background fields at mesopic and photopic light levels (i.e., 0.06–110 cd/m2) for retinal eccentricities from 0° to 15° using three combinations of background/test field sizes (i.e., 10°/2°, 10°/0.45°, and 1°/0.45°). A two-channel Maxwellian view optical system was employed to eliminate pupil effects on the measured thresholds. A model based on visual mechanisms that were described in the literature was optimized to fit the measured luminance thresholds in all experimental conditions. Our results can be described by a combination of visual mechanisms. We determined how spatial summation changed with eccentricity and how subtractive adaptation changed with eccentricity and background field size. According to our model, photon noise plays a significant role to explain contrast detection thresholds measured with the 1/0.45° background/test size combination at mesopic luminances and at off-axis eccentricities. In these conditions, our data reflect the presence of rod-cone interaction for eccentricities between 6° and 9° and luminances between 0.6 and 5 cd/m2. In spite of the increasing noise effects with eccentricity, results also show that the visual system tends to maintain a constant signal-to-noise ratio in the off-axis detection task over the whole mesopic range. PMID:27210038

Influence of background size, luminance and eccentricity on different adaptation mechanisms.

PubMed

Gloriani, Alejandro H; Matesanz, Beatriz M; Barrionuevo, Pablo A; Arranz, Isabel; Issolio, Luis; Mar, Santiago; Aparicio, Juan A

2016-08-01

Mechanisms of light adaptation have been traditionally explained with reference to psychophysical experimentation. However, the neural substrata involved in those mechanisms remain to be elucidated. Our study analyzed links between psychophysical measurements and retinal physiological evidence with consideration for the phenomena of rod-cone interactions, photon noise, and spatial summation. Threshold test luminances were obtained with steady background fields at mesopic and photopic light levels (i.e., 0.06-110cd/m(2)) for retinal eccentricities from 0° to 15° using three combinations of background/test field sizes (i.e., 10°/2°, 10°/0.45°, and 1°/0.45°). A two-channel Maxwellian view optical system was employed to eliminate pupil effects on the measured thresholds. A model based on visual mechanisms that were described in the literature was optimized to fit the measured luminance thresholds in all experimental conditions. Our results can be described by a combination of visual mechanisms. We determined how spatial summation changed with eccentricity and how subtractive adaptation changed with eccentricity and background field size. According to our model, photon noise plays a significant role to explain contrast detection thresholds measured with the 1/0.45° background/test size combination at mesopic luminances and at off-axis eccentricities. In these conditions, our data reflect the presence of rod-cone interaction for eccentricities between 6° and 9° and luminances between 0.6 and 5cd/m(2). In spite of the increasing noise effects with eccentricity, results also show that the visual system tends to maintain a constant signal-to-noise ratio in the off-axis detection task over the whole mesopic range. Copyright © 2016 Elsevier Ltd. All rights reserved.

Kinetic Inductance Detectors for Measuring the Polarization of the Cosmic Microwave Background

NASA Astrophysics Data System (ADS)

Flanigan, Daniel

Kinetic inductance detectors (KIDs) are superconducting thin-film microresonators that are sensitive photon detectors. These detectors are a candidate for the next generation of experiments designed to measure the polarization of the cosmic microwave background (CMB). I discuss the basic theory needed to understand the response of a KID to light, focusing on the dynamics of the quasiparticle system. I derive an equation that describes the dynamics of the quasiparticle number, solve it in a simplified form not previously published, and show that it can describe the dynamic response of a detector. Magnetic flux vortices in a superconducting thin film can be a significant source of dissipation, and I demonstrate some techniques to prevent their formation. Based on the presented theory, I derive a corrected version of a widely-used equation for the quasiparticle recombination noise in a KID. I show that a KID consisting of a lumped-element resonator can be sensitive enough to be limited by photon noise, which is the fundamental limit for photometry, at a level of optical loading below levels in ground-based CMB experiments. Finally, I describe an ongoing project to develop multichroic KID pixels that are each sensitive to two linear polarization states in two spectral bands, intended for the next generation of CMB experiments. I show that a prototype 23-pixel array can detect millimeter-wave light, and present characterization measurements of the detectors.

75 FR 13142 - Florida Power and Light Company; Turkey Point, Units 3 and 4; Exemption

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-18

... Light Company; Turkey Point, Units 3 and 4; Exemption 1.0 Background Florida Power and Light Company... ferritic materials of pressure-retaining components of the reactor coolant pressure boundary of light water... reactor coolant pressure boundary of light water nuclear power reactors to provide adequate margins of...

Elucidating the interaction between light competition and herbivore feeding patterns using functional–structural plant modelling

PubMed Central

de Vries, Jorad; Poelman, Erik H; Anten, Niels; Evers, Jochem B

2018-01-01

Abstract Background and Aims Plants usually compete with neighbouring plants for resources such as light as well as defend themselves against herbivorous insects. This requires investment of limiting resources, resulting in optimal resource distribution patterns and trade-offs between growth- and defence-related traits. A plant’s competitive success is determined by the spatial distribution of its resources in the canopy. The spatial distribution of herbivory in the canopy in turn differs between herbivore species as the level of herbivore specialization determines their response to the distribution of resources and defences in the canopy. Here, we investigated to what extent competition for light affects plant susceptibility to herbivores with different feeding preferences. Methods To quantify interactions between herbivory and competition, we developed and evaluated a 3-D spatially explicit functional–structural plant model for Brassica nigra that mechanistically simulates competition in a dynamic light environment, and also explicitly models leaf area removal by herbivores with different feeding preferences. With this novel approach, we can quantitatively explore the extent to which herbivore feeding location and light competition interact in their effect on plant performance. Key Results Our results indicate that there is indeed a strong interaction between levels of plant–plant competition and herbivore feeding preference. When plants did not compete, herbivory had relatively small effects irrespective of feeding preference. Conversely, when plants competed, herbivores with a preference for young leaves had a strong negative effect on the competitiveness and subsequent performance of the plant, whereas herbivores with a preference for old leaves did not. Conclusions Our study predicts how plant susceptibility to herbivory depends on the composition of the herbivore community and the level of plant competition, and highlights the importance of considering the full range of dynamics in plant–plant–herbivore interactions. PMID:29373660

Why is Light Text Harder to Read Than Dark Text?

NASA Technical Reports Server (NTRS)

Scharff, Lauren V.; Ahumada, Albert J.

2005-01-01

Scharff and Ahumada (2002, 2003) measured text legibility for light text and dark text. For paragraph readability and letter identification, responses to light text were slower and less accurate for a given contrast. Was this polarity effect (1) an artifact of our apparatus, (2) a physiological difference in the separate pathways for positive and negative contrast or (3) the result of increased experience with dark text on light backgrounds? To rule out the apparatus-artifact hypothesis, all data were collected on one monitor. Its luminance was measured at all levels used, and the spatial effects of the monitor were reduced by pixel doubling and quadrupling (increasing the viewing distance to maintain constant angular size). Luminances of vertical and horizontal square-wave gratings were compared to assess display speed effects. They existed, even for 4-pixel-wide bars. Tests for polarity asymmetries in display speed were negative. Increased experience might develop full letter templates for dark text, while recognition of light letters is based on component features. Earlier, an observer ran all conditions at one polarity and then switched. If dark and light letters were intermixed, the observer might use component features on all trials and do worse on the dark letters, reducing the polarity effect. We varied polarity blocking (completely blocked, alternating smaller blocks, and intermixed blocks). Letter identification responses times showed polarity effects at all contrasts and display resolution levels. Observers were also more accurate with higher contrasts and more pixels per degree. Intermixed blocks increased the polarity effect by reducing performance on the light letters, but only if the randomized block occurred prior to the nonrandomized block. Perhaps observers tried to use poorly developed templates, or they did not work as hard on the more difficult items. The experience hypothesis and the physiological gain hypothesis remain viable explanations.

The collection of images of an insulator taken outdoors in varying lighting conditions with additional laser spots.

PubMed

Tomaszewski, Michał; Ruszczak, Bogdan; Michalski, Paweł

2018-06-01

Electrical insulators are elements of power lines that require periodical diagnostics. Due to their location on the components of high-voltage power lines, their imaging can be cumbersome and time-consuming, especially under varying lighting conditions. Insulator diagnostics with the use of visual methods may require localizing insulators in the scene. Studies focused on insulator localization in the scene apply a number of methods, including: texture analysis, MRF (Markov Random Field), Gabor filters or GLCM (Gray Level Co-Occurrence Matrix) [1], [2]. Some methods, e.g. those which localize insulators based on colour analysis [3], rely on object and scene illumination, which is why the images from the dataset are taken under varying lighting conditions. The dataset may also be used to compare the effectiveness of different methods of localizing insulators in images. This article presents high-resolution images depicting a long rod electrical insulator under varying lighting conditions and against different backgrounds: crops, forest and grass. The dataset contains images with visible laser spots (generated by a device emitting light at the wavelength of 532 nm) and images without such spots, as well as complementary data concerning the illumination level and insulator position in the scene, the number of registered laser spots, and their coordinates in the image. The laser spots may be used to support object-localizing algorithms, while the images without spots may serve as a source of information for those algorithms which do not need spots to localize an insulator.

Is "good enough" good enough for portable visible and near-visible spectrometry?

NASA Astrophysics Data System (ADS)

Scheeline, Alexander

2015-06-01

Some uses of portable spectrometers require the same quality as laboratory instruments. Such quality is challenging because of temperature and humidity variation, dust, and vibration. Typically, one chooses materials and mechanical layout to minimize the influence of these noise and background sources. Mechanical stability is constrained by limits on instrument mass and ergonomics. An alternative approach is to make minimally adequate hardware, compensating for variability in software. We describe an instrument developed specifically to use software to compensate for marginal hardware. An initial instantiation of the instrument is limited to 430 - 700 nm. Simple changes will allow expansion to cover 315 - 1000 nm. Outside this range, costs are likely to increase significantly. Inherent wavelength calibration comes from knowing the peak emission wavelength of an LED light source, and fitting of instrument dispersion to a model of order placement with each measurement. Dynamic range is determined by the product of camera response and intentionally wide throughput variation among hundreds of diffraction orders. Resolution degrades gracefully at low light levels, but is limited to ~ 2 nm at high light levels as initially fabricated and ~ 1 nm in principle. Stray light may be measured in real-time. Diffuse stray light can be employed for turbidimetry fluorimetry, and to aid compensation of working curve nonlinearity. While unsuitable for, Raman spectroscopy, the instrument shows promise for absorption, fluorescence, reflectance, and surface plasmon resonance spectrometries. To aid non-expert users, real-time training, measurement sequencing, and outcome interpretation are programmed with QR codes or web-linked instructions.

Stray light suppression of optical and mechanical system for telescope detection

NASA Astrophysics Data System (ADS)

Wang, Lei; Ma, Wenli

2013-09-01

During telescope detection, there is atmosphere overflow and other stray light affecting the system which leads to background disturbance. Thus reduce the detection capability of the system. So it is very necessary to design mechanical structure to suppress the stray light for the telescope detection system. It can both improve the signal-to-noise and contrast of the object. This paper designs the optical and mechanical structure of the 400mm telescope. And then the main baffle, baffle vane, field stop and coating technology are used to eliminate the effect of stray light on the optical and mechanical system. Finally, software is used to analyze and simulate stray light on the whole optical and mechanical system. Using PST as the evaluating standard, separate and integrated analysis of the suppressing effect of main baffle, baffle vane and field aperture is completed. And also get the results of PST before and after eliminating the stray light. Meanwhile, the results of stray light analysis can be used to guide the design of the optical and mechanical structure. The analysis results demonstrate that reasonable optical and mechanical structure and stray light suppression measure can highly reduce the PST and also improve the detection capability of the telescope system, and the designed outside baffle, inside baffle, vanes and coating technique etc. can decrease the PST approximately 1 to 3 level.

EEG Beta Power but Not Background Music Predicts the Recall Scores in a Foreign-Vocabulary Learning Task.

PubMed

Küssner, Mats B; de Groot, Annette M B; Hofman, Winni F; Hillen, Marij A

2016-01-01

As tantalizing as the idea that background music beneficially affects foreign vocabulary learning may seem, there is-partly due to a lack of theory-driven research-no consistent evidence to support this notion. We investigated inter-individual differences in the effects of background music on foreign vocabulary learning. Based on Eysenck's theory of personality we predicted that individuals with a high level of cortical arousal should perform worse when learning with background music compared to silence, whereas individuals with a low level of cortical arousal should be unaffected by background music or benefit from it. Participants were tested in a paired-associate learning paradigm consisting of three immediate word recall tasks, as well as a delayed recall task one week later. Baseline cortical arousal assessed with spontaneous EEG measurement in silence prior to the learning rounds was used for the analyses. Results revealed no interaction between cortical arousal and the learning condition (background music vs. silence). Instead, we found an unexpected main effect of cortical arousal in the beta band on recall, indicating that individuals with high beta power learned more vocabulary than those with low beta power. To substantiate this finding we conducted an exact replication of the experiment. Whereas the main effect of cortical arousal was only present in a subsample of participants, a beneficial main effect of background music appeared. A combined analysis of both experiments suggests that beta power predicts the performance in the word recall task, but that there is no effect of background music on foreign vocabulary learning. In light of these findings, we discuss whether searching for effects of background music on foreign vocabulary learning, independent of factors such as inter-individual differences and task complexity, might be a red herring. Importantly, our findings emphasize the need for sufficiently powered research designs and exact replications of theory-driven experiments when investigating effects of background music and inter-individual variation on task performance.

EEG Beta Power but Not Background Music Predicts the Recall Scores in a Foreign-Vocabulary Learning Task

PubMed Central

de Groot, Annette M. B.; Hofman, Winni F.; Hillen, Marij A.

2016-01-01

As tantalizing as the idea that background music beneficially affects foreign vocabulary learning may seem, there is—partly due to a lack of theory-driven research—no consistent evidence to support this notion. We investigated inter-individual differences in the effects of background music on foreign vocabulary learning. Based on Eysenck’s theory of personality we predicted that individuals with a high level of cortical arousal should perform worse when learning with background music compared to silence, whereas individuals with a low level of cortical arousal should be unaffected by background music or benefit from it. Participants were tested in a paired-associate learning paradigm consisting of three immediate word recall tasks, as well as a delayed recall task one week later. Baseline cortical arousal assessed with spontaneous EEG measurement in silence prior to the learning rounds was used for the analyses. Results revealed no interaction between cortical arousal and the learning condition (background music vs. silence). Instead, we found an unexpected main effect of cortical arousal in the beta band on recall, indicating that individuals with high beta power learned more vocabulary than those with low beta power. To substantiate this finding we conducted an exact replication of the experiment. Whereas the main effect of cortical arousal was only present in a subsample of participants, a beneficial main effect of background music appeared. A combined analysis of both experiments suggests that beta power predicts the performance in the word recall task, but that there is no effect of background music on foreign vocabulary learning. In light of these findings, we discuss whether searching for effects of background music on foreign vocabulary learning, independent of factors such as inter-individual differences and task complexity, might be a red herring. Importantly, our findings emphasize the need for sufficiently powered research designs and exact replications of theory-driven experiments when investigating effects of background music and inter-individual variation on task performance. PMID:27537520

Display conditions and lesion detectability: effect of background light

NASA Astrophysics Data System (ADS)

Razavi, Mahmood; Hall, Theodore R.; Aberle, Denise R.; Hayrapetian, Alek S.; Loloyan, Mansur; Eldredge, Sandra L.

1990-08-01

We assessed the effect of high background light on observer performance for the detection of a variety of chest radiographic abnormalities. Five observers reviewed 66 digital hard copy chest images formatted to 1 1 x 14 inch size under two display conditions: 1) on a specially prepared 1 1 x 14 inch illuminated panel with no peripheral light and 2) on a standard viewing panel designed for 14 x 17 inch radiographs. The images contained one - or more of the following conditions: pneumothorax, interstitial disease, nodules, alveolar process, or no abnormality. The results of receiver operator characteristic analysis show that extraneous light does reduce observer performance and the detectability of nodules, interstitial disease.

Fiber Optics: A New World of Possibilities in Light.

ERIC Educational Resources Information Center

Hutchinson, John

1990-01-01

The background and history of light and fiber optics are discussed. Applications for light passed either directly or indirectly through optical fibers are described. Suggestions for science activities that use fiber optics are provided. (KR)

Increased visual sensitivity following periods of dim illumination.

PubMed

McKeown, Alex S; Kraft, Timothy W; Loop, Michael S

2015-02-19

We measured changes in the sensitivity of the human rod pathway by testing visual reaction times before and after light adaptation. We targeted a specific range of conditioning light intensities to see if a physiological adaptation recently discovered in mouse rods is observable at the perceptual level in humans. We also measured the noise spectrum of single mouse rods due to the importance of the signal-to-noise ratio in rod to rod bipolar cell signal transfer. Using the well-defined relationship between stimulus intensity and reaction time (Piéron's law), we measured the reaction times of eight human subjects (ages 24-66) to scotopic test flashes of a single intensity before and after the presentation of a 3-minute background. We also made recordings from single mouse rods and processed the cellular noise spectrum before and after similar conditioning exposures. Subject reaction times to a fixed-strength stimulus were fastest 5 seconds after conditioning background exposure (79% ± 1% of the preconditioning mean, in darkness) and were significantly faster for the first 12 seconds after background exposure (P < 0.01). During the period of increased rod sensitivity, the continuous noise spectrum of individual mouse rods was not significantly increased. A decrease in human reaction times to a dim flash after conditioning background exposure may originate in rod photoreceptors through a transient increase in the sensitivity of the phototransduction cascade. There is no accompanying increase in rod cellular noise, allowing for reliable transmission of larger rod signals after conditioning exposures and the observed increase in perceptual sensitivity. Copyright 2015 The Association for Research in Vision and Ophthalmology, Inc.

Heterodyne effect in Hybrid CARS

NASA Astrophysics Data System (ADS)

Wang, Xi; Zhang, Aihua; Zhi, Miaochan; Sokolov, Alexei; Welch, George; Scully, Marlan

2009-10-01

We study the interaction between the resonant Raman signal and non-Raman field, either the concomitant nonresonant four-wave-mixing (FWM) background or an applied external field, in our recently developed scheme of coherent Anti-Stokes Raman scattering, a hybrid CARS. Our technique combines instantaneous coherent excitation of several characteristic molecular vibrations with subsequent probing of these vibrations by an optimally shaped, time-delayed, narrowband laser pulse. This pulse configuration mitigates the non-resonant FWM background while maximizing the Raman-resonant signal, and allows rapid and highly specific detection even in the presence of multiple scattering. We apply this method to non-invasive monitoring of blood glucose levels. Under certain conditions we find that the measured signal is linearly proportional to the glucose concentration due to optical interference with the residual background light, which allows reliable detection of spectral signatures down to medically-relevant glucose levels. We also study the interference between the CARS field and an external field (the local oscillator) by controlling their relative phase and amplitude. This control allows direct observation of the real and imaginary components of the third-order nonlinear susceptibility (χ^(3)) of the sample. We demonstrate that the heterodyne method can be used to amplify the signal and thus increase detection sensitivity.

Dynamic compartment specific changes in glutathione and ascorbate levels in Arabidopsis plants exposed to different light intensities

PubMed Central

2013-01-01

Background Excess light conditions induce the generation of reactive oxygen species (ROS) directly in the chloroplasts but also cause an accumulation and production of ROS in peroxisomes, cytosol and vacuoles. Antioxidants such as ascorbate and glutathione occur in all cell compartments where they detoxify ROS. In this study compartment specific changes in antioxidant levels and related enzymes were monitored among Arabidopsis wildtype plants and ascorbate and glutathione deficient mutants (vtc2-1 and pad2-1, respectively) exposed to different light intensities (50, 150 which was considered as control condition, 300, 700 and 1,500 μmol m-2 s-1) for 4 h and 14 d. Results The results revealed that wildtype plants reacted to short term exposure to excess light conditions with the accumulation of ascorbate and glutathione in chloroplasts, peroxisomes and the cytosol and an increased activity of catalase in the leaves. Long term exposure led to an accumulation of ascorbate and glutathione mainly in chloroplasts. In wildtype plants an accumulation of ascorbate and hydrogen peroxide (H2O2) could be observed in vacuoles when exposed to high light conditions. The pad2-1 mutant reacted to long term excess light exposure with an accumulation of ascorbate in peroxisomes whereas the vtc2-1 mutant reacted with an accumulation of glutathione in the chloroplasts (relative to the wildtype) and nuclei during long term high light conditions indicating an important role of these antioxidants in these cell compartments for the protection of the mutants against high light stress. Conclusion The results obtained in this study demonstrate that the accumulation of ascorbate and glutathione in chloroplasts, peroxisomes and the cytosol is an important reaction of plants to short term high light stress. The accumulation of ascorbate and H2O2 along the tonoplast and in vacuoles during these conditions indicates an important route for H2O2 detoxification under these conditions. PMID:23865417

New Spectral Evidence of an Unaccounted Component of the Near-infrared Extragalactic Background Light from the CIBER

NASA Astrophysics Data System (ADS)

Matsuura, Shuji; Arai, Toshiaki; Bock, James J.; Cooray, Asantha; Korngut, Phillip M.; Kim, Min Gyu; Lee, Hyung Mok; Lee, Dae Hee; Levenson, Louis R.; Matsumoto, Toshio; Onishi, Yosuke; Shirahata, Mai; Tsumura, Kohji; Wada, Takehiko; Zemcov, Michael

2017-04-01

The extragalactic background light (EBL) captures the total integrated emission from stars and galaxies throughout the cosmic history. The amplitude of the near-infrared EBL from space absolute photometry observations has been controversial and depends strongly on the modeling and subtraction of the zodiacal light (ZL) foreground. We report the first measurement of the diffuse background spectrum at 0.8-1.7 μm from the CIBER experiment. The observations were obtained with an absolute spectrometer over two flights in multiple sky fields to enable the subtraction of ZL, stars, terrestrial emission, and diffuse Galactic light. After subtracting foregrounds and accounting for systematic errors, we find the nominal EBL brightness, assuming the Kelsall ZL model, is {42.7}-10.6+11.9 nW m-2 sr-1 at 1.4 μm. We also analyzed the data using the Wright ZL model, which results in a worse statistical fit to the data and an unphysical EBL, falling below the known background light from galaxies at λ < 1.3 μm. Using a model-independent analysis based on the minimum EBL brightness, we find an EBL brightness of {28.7}-3.3+5.1 nWm-2 sr-1 at 1.4 μm. While the derived EBL amplitude strongly depends on the ZL model, we find that we cannot fit the spectral data to ZL, Galactic emission, and EBL from solely integrated galactic light from galaxy counts. The results require a new diffuse component, such as an additional foreground or an excess EBL with a redder spectrum than that of ZL.

An accurate laser radiometer for determining visible exposure times.

PubMed

Royston, D D

1985-01-01

A laser light radiometer has been developed for the Electro-Optics Branch of the Center for Devices and Radiological Health (CDRH). The radiometer measures direct laser radiation emitted in the visible spectrum. Based upon this measurement, the instrument's microprocessor automatically determines at what time duration the exposure to the measured laser radiation would exceed either the class I accessible emission limits of the Federal Performance Standard for laser products or the maximum permissible exposure limits of laser user safety standards. The instrument also features automatic background level compensation, pulse measurement capability, and self-diagnosis. Measurement of forward surface illumination levels preceding HpD photoradiation therapy is possible.

Globally Convergent Numerical Methods for Coefficient Inverse Problems

DTIC Science & Technology

2008-09-23

backgrounds. Probing radiations are usually thought as electric and acoustic waves for the first two applications and light originated by lasers in...fundamental laws of physics. Electric , acoustic or light scattering properties of both unknown targets and the backgrounds are described by coefficients of...with the back-reflected data here, Army applications are quite feasible. The 2-D inverse problem of the determination of the unknown electric

A Search for Quasi-periodic Oscillations in the Blazar 1ES 1959+650

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

Li, Xiao-Pan; Luo, Yu-Hui; Yang, Hai-Yan

We have searched quasi-periodic oscillations (QPOs) in the 15 GHz light curve of the BL Lac object 1ES 1959+650 monitored by the Owens Valley Radio Observatory 40 m telescope during the period from 2008 January to 2016 February, using the Lomb–Scargle Periodogram, power spectral density (PSD), discrete autocorrelation function, and phase dispersion minimization (PDM) techniques. The red noise background has been established via the PSD method, and no QPO can be derived at the 3 σ confidence level accounting for the impact of the red noise variability. We conclude that the light curve of 1ES 1959+650 can be explained bymore » a stochastic red noise process that contributes greatly to the total observed variability amplitude, dominates the power spectrum, causes spurious bumps and wiggles in the autocorrelation function and can result in the variance of the folded light curve decreasing toward lower temporal frequencies when few-cycle, sinusoid-like patterns are present. Moreover, many early supposed periodicity claims for blazar light curves need to be reevaluated assuming red noise.« less

Photometry-based estimation of the total number of stars in the Universe.

PubMed

Manojlović, Lazo M

2015-07-20

A novel photometry-based estimation of the total number of stars in the Universe is presented. The estimation method is based on the energy conservation law and actual measurements of the extragalactic background light levels. By assuming that every radiated photon is kept within the Universe volume, i.e., by approximating the Universe as an integrating cavity without losses, the total number of stars in the Universe of about 6×10²² has been obtained.

Study on real-time images compounded using spatial light modulator

NASA Astrophysics Data System (ADS)

Xu, Jin; Chen, Zhebo; Ni, Xuxiang; Lu, Zukang

2007-01-01

Image compounded technology is often used on film and its facture. In common, image compounded use image processing arithmetic, get useful object, details, background or some other things from the images firstly, then compounding all these information into one image. When using this method, the film system needs a powerful processor, for the process function is very complex, we get the compounded image for a few time delay. In this paper, we introduce a new method of image real-time compounded, use this method, we can do image composite at the same time with movie shot. The whole system is made up of two camera-lens, spatial light modulator array and image sensor. In system, the spatial light modulator could be liquid crystal display (LCD), liquid crystal on silicon (LCoS), thin film transistor liquid crystal display (TFTLCD), Deformable Micro-mirror Device (DMD), and so on. Firstly, one camera-lens images the object on the spatial light modulator's panel, we call this camera-lens as first image lens. Secondly, we output an image to the panel of spatial light modulator. Then, the image of the object and image that output by spatial light modulator will be spatial compounded on the panel of spatial light modulator. Thirdly, the other camera-lens images the compounded image to the image sensor, and we call this camera-lens as second image lens. After these three steps, we will gain the compound images by image sensor. For the spatial light modulator could output the image continuously, then the image will be compounding continuously too, and the compounding procedure is completed in real-time. When using this method to compounding image, if we will put real object into invented background, we can output the invented background scene on the spatial light modulator, and the real object will be imaged by first image lens. Then, we get the compounded images by image sensor in real time. The same way, if we will put real background to an invented object, we can output the invented object on the spatial light modulator and the real background will be imaged by first image lens. Then, we can also get the compounded images by image sensor real time. Commonly, most spatial light modulator only can do modulate light intensity, so we can only do compounding BW images if use only one panel which without color filter. If we will get colorful compounded image, we need use the system like three spatial light modulator panel projection. In the paper, the system's optical system framework we will give out. In all experiment, the spatial light modulator used liquid crystal on silicon (LCoS). At the end of the paper, some original pictures and compounded pictures will be given on it. Although the system has a few shortcomings, we can conclude that, using this system to compounding images has no delay to do mathematic compounding process, it is a really real time images compounding system.

PHYTOCHROME KINASE SUBSTRATE1 Regulates Root Phototropism and Gravitropism1[C][W][OA

PubMed Central

Boccalandro, Hernán E.; De Simone, Silvia N.; Bergmann-Honsberger, Ariane; Schepens, Isabelle; Fankhauser, Christian; Casal, Jorge J.

2008-01-01

Light promotes the expression of PHYTOCHROME KINASE SUBSTRATE1 (PKS1) in the root of Arabidopsis thaliana, but the function of PKS1 in this organ is unknown. Unilateral blue light induced a negative root phototropic response mediated by phototropin 1 in wild-type seedlings. This response was absent in pks1 mutants. In the wild type, unilateral blue light enhanced PKS1 expression in the subapical region of the root several hours before bending was detectable. The negative phototropism and the enhanced PKS1 expression in response to blue light required phytochrome A (phyA). In addition, the pks1 mutation enhanced the root gravitropic response when vertically oriented seedlings were placed horizontally. The negative regulation of gravitropism by PKS1 occurred even in dark-grown seedlings and did not require phyA. Blue light also failed to induce negative phototropism in pks1 under reduced gravitational stimulation, indicating that the effect of pks1 on phototropism is not simply the consequence of the counteracting effect of enhanced gravitropism. We propose a model where the background level of PKS1 reduces gravitropism. After a phyA-dependent increase in its expression, PKS1 positively affects root phototropism and both effects contribute to negative curvature in response to unilateral blue light. PMID:18024556

PHYTOCHROME KINASE SUBSTRATE1 regulates root phototropism and gravitropism.

PubMed

Boccalandro, Hernán E; De Simone, Silvia N; Bergmann-Honsberger, Ariane; Schepens, Isabelle; Fankhauser, Christian; Casal, Jorge J

2008-01-01

Light promotes the expression of PHYTOCHROME KINASE SUBSTRATE1 (PKS1) in the root of Arabidopsis thaliana, but the function of PKS1 in this organ is unknown. Unilateral blue light induced a negative root phototropic response mediated by phototropin 1 in wild-type seedlings. This response was absent in pks1 mutants. In the wild type, unilateral blue light enhanced PKS1 expression in the subapical region of the root several hours before bending was detectable. The negative phototropism and the enhanced PKS1 expression in response to blue light required phytochrome A (phyA). In addition, the pks1 mutation enhanced the root gravitropic response when vertically oriented seedlings were placed horizontally. The negative regulation of gravitropism by PKS1 occurred even in dark-grown seedlings and did not require phyA. Blue light also failed to induce negative phototropism in pks1 under reduced gravitational stimulation, indicating that the effect of pks1 on phototropism is not simply the consequence of the counteracting effect of enhanced gravitropism. We propose a model where the background level of PKS1 reduces gravitropism. After a phyA-dependent increase in its expression, PKS1 positively affects root phototropism and both effects contribute to negative curvature in response to unilateral blue light.

Correlative Light- and Electron Microscopy Using Quantum Dot Nanoparticles.

PubMed

Killingsworth, Murray C; Bobryshev, Yuri V

2016-08-07

A method is described whereby quantum dot (QD) nanoparticles can be used for correlative immunocytochemical studies of human pathology tissue using widefield fluorescence light microscopy and transmission electron microscopy (TEM). To demonstrate the protocol we have immunolabeled ultrathin epoxy sections of human somatostatinoma tumor using a primary antibody to somatostatin, followed by a biotinylated secondary antibody and visualization with streptavidin conjugated 585 nm cadmium-selenium (CdSe) quantum dots (QDs). The sections are mounted on a TEM specimen grid then placed on a glass slide for observation by widefield fluorescence light microscopy. Light microscopy reveals 585 nm QD labeling as bright orange fluorescence forming a granular pattern within the tumor cell cytoplasm. At low to mid-range magnification by light microscopy the labeling pattern can be easily recognized and the level of non-specific or background labeling assessed. This is a critical step for subsequent interpretation of the immunolabeling pattern by TEM and evaluation of the morphological context. The same section is then blotted dry and viewed by TEM. QD probes are seen to be attached to amorphous material contained in individual secretory granules. Images are acquired from the same region of interest (ROI) seen by light microscopy for correlative analysis. Corresponding images from each modality may then be blended to overlay fluorescence data on TEM ultrastructure of the corresponding region.

The physics of background discrimination in liquid xenon, and first results from Xenon10 in the hunt for WIMP dark matter

NASA Astrophysics Data System (ADS)

Dahl, Carl Eric

2009-06-01

The WIMP limit set by the Xenon10 experiment in 2007 signals a new era in direct detection of dark matter, with several large-scale liquid target detectors now under construction. A major challenge in these detectors will be to understand backgrounds at the level necessary to claim a positive WIMP signal. In liquid xenon, these backgrounds are dominated by electron recoils, which may be distinguished from the WIMP signal (nuclear recoils) by their higher charge-to-light ratio. During the construction and operation of Xenon10, the prototype detector Xed probed the physics of this discrimination. Particle interactions in liquid xenon both ionize and excite xenon atoms, giving charge and scintillation signals, respectively. Some fraction of ions recombine, reducing the charge signal and creating additional scintillation. The charge-to-light ratio, determined by the initial exciton-ion ratio and the ion recombination fraction, provides the basis for discrimination between electron and nuclear recoils. Intrinsic fluctuations in the recombination fraction limit discrimination. Changes in recombination induce an exact anti-correlation between charge and light, and when calibrated this anti-correlation distinguishes recombination fluctuations from uncorrelated fluctuations in the measured signals. We determine the mean recombination and recombination fluctuations as a function of energy and applied field for electron and nuclear recoils, finding that recombination fluctuations are already the limiting factor for discrimination above ~12 keVr (nuclear recoil energy). Below 12 keVr statistical fluctuations in the number of scintillation photons counted dominate, and we project a x6 improvement in background rejection with a x2 increase in light collection efficiency. We also build a simple recombination model that successfully reproduces the mean recombination in electron and nuclear recoils, including the surprising reversal of the expected trend for recombination with ionization density in low energy electron recoils. The model also reproduces the measured recombination fluctuations to within a factor of two at high energies. Surprisingly, the model suggests that recombination at low energies is independent of ionization density, and our observed discrimination is due not to the different stopping powers of electrons and nuclei as was thought, but rather to a different initial exciton-ion ratio. We suggest two possible physical models for this new result.

Calcium and magnesium fluxes across the plasma membrane of the toad rod outer segment.

PubMed Central

Nakatani, K; Yau, K W

1988-01-01

1. Membrane current was recorded from an isolated, dark-adapted toad rod by sucking either its inner segment or outer segment into a tight-fitting glass pipette containing Ringer solution. The remainder of the cell was exposed to bath solution which could be changed rapidly. 2. In normal Ringer solution the current response of a cell to a saturating flash or step of light showed a small secondary rise at its initial peak. The profile of this secondary rise (i.e. amplitude and time course) was independent of both the intensity and the duration of illumination once the light response had reached a plateau level. 3. This secondary rise disappeared when external Na+ around the outer segment was replaced by Li+ or guanidinium, suggesting that it represented an electrogenic Na+-dependent Ca2+ efflux which was declining after the onset of light. 4. This Na+-Ca2+ exchange activity showed a roughly exponential decline, with a time constant of about 0.5 s. Exponential extrapolation of the exchange current to the time at half-height of the light response gave an initial amplitude of about 2 pA. Using La3+ as a blocker, we did not detect any steady exchange current after the initial exponential decline. 5. An intense flash superposed on a just-saturating steady background light failed to produce any incremental exchange current transient. 6. Our interpretation of the above results is that in darkness there are counterbalancing levels of Ca2+ influx (through the light-sensitive conductance) and efflux (through the Na+-Ca2+ exchange) across the plasma membrane of the rod outer segment. The exchange current transient at the onset of light merely represents the unidirectional Ca2+ efflux which becomes revealed as a result of the stoppage of the Ca2+ influx, rather than a de novo Ca2+ efflux triggered by light. 7. Consistent with this interpretation, a test light delivered soon after a saturating, conditioning light elicited little exchange current, which then gradually recovered to control value with a time course parallel to the restoration of the dark current. Conversely, when the dark current was increased above its physiological level by IBMX (isobutylmethylxanthine) the exchange current transient became larger than control.(ABSTRACT TRUNCATED AT 400 WORDS) Images Fig. 8 PMID:2457685

High contrast imaging through adaptive transmittance control in the focal plane

NASA Astrophysics Data System (ADS)

Dhadwal, Harbans S.; Rastegar, Jahangir; Feng, Dake

2016-05-01

High contrast imaging, in the presence of a bright background, is a challenging problem encountered in diverse applications ranging from the daily chore of driving into a sun-drenched scene to in vivo use of biomedical imaging in various types of keyhole surgeries. Imaging in the presence of bright sources saturates the vision system, resulting in loss of scene fidelity, corresponding to low image contrast and reduced resolution. The problem is exacerbated in retro-reflective imaging systems where the light sources illuminating the object are unavoidably strong, typically masking the object features. This manuscript presents a novel theoretical framework, based on nonlinear analysis and adaptive focal plane transmittance, to selectively remove object domain sources of background light from the image plane, resulting in local and global increases in image contrast. The background signal can either be of a global specular nature, giving rise to parallel illumination from the entire object surface or can be represented by a mosaic of randomly orientated, small specular surfaces. The latter is more representative of real world practical imaging systems. Thus, the background signal comprises of groups of oblique rays corresponding to distributions of the mosaic surfaces. Through the imaging system, light from group of like surfaces, converges to a localized spot in the focal plane of the lens and then diverges to cast a localized bright spot in the image plane. Thus, transmittance of a spatial light modulator, positioned in the focal plane, can be adaptively controlled to block a particular source of background light. Consequently, the image plane intensity is entirely due to the object features. Experimental image data is presented to verify the efficacy of the methodology.

Exposure to Visible Light Emitted from Smartphones and Tablets Increases the Proliferation of Staphylococcus aureus: Can this be Linked to Acne?

PubMed Central

Taheri, M.; Darabyan, M.; Izadbakhsh, E.; Nouri, F.; Haghani, M.; Mortazavi, S.A.R.; Mortazavi, G.; Mortazavi, S.M.J.; Moradi, M.

2017-01-01

Background: Due to rapid advances in modern technologies such as telecommunication technology, the world has witnessed an exponential growth in the use of digital handheld devices (e.g. smartphones and tablets). This drastic growth has resulted in increased global concerns about the safety of these devices. Smartphones, tablets, laptops, and other digital screens emit high levels of short-wavelength visible light (i.e. blue color region in the visible light spectrum). Material and Methods: At a dark environment, Staphylococcus aureus bacteria were exposed to the light emitted from common tablets/smartphones. The control samples were exposed to the same intensity of light generated by a conventional incandescent light bulb. The growth rate of bacteria was examined by measuring the optical density (OD) at 625 nm by using a spectrophotometer before the light exposure and after 30 to 330 minutes of light exposure. Results: The growth rates of bacteria in both smartphone and tablet groups were higher than that of the control group and the maximum smartphone/control and tablet/control growth ratios were observed in samples exposed to digital screens’ light for 300 min (ratios of 3.71 and 3.95, respectively). Conclusion: To the best of our knowledge, this is the first study that investigates the effect of exposure to light emitted from digital screens on the proliferation of Staphylococcus aureus and its association with acne pathogenesis. Our findings show that exposure to short-wavelength visible light emitted from smartphones and tablets can increase the proliferation of Staphylococcus aureus. PMID:28580338

Rejection of randomly coinciding 2ν2β events in ZnMoO4 scintillating bolometers

NASA Astrophysics Data System (ADS)

Chernyak, D. M.; Danevich, F. A.; Giuliani, A.; Mancuso, M.; Nones, C.; Olivieri, E.; Tenconi, M.; Tretyak, V. I.

2014-01-01

Random coincidence of 2ν2β decay events could be one of the main sources of background for 0ν2β decay in cryogenic bolometers due to their poor time resolution. Pulse-shape discrimination by using front edge analysis, the mean-time and χ2 methods was applied to discriminate randomly coinciding 2ν2β events in ZnMoO4 cryogenic scintillating bolometers. The background can be effectively rejected on the level of 99% by the mean-time analysis of heat signals with the rise time about 14 ms and the signal-to-noise ratio 900, and on the level of 98% for the light signals with 3 ms rise time and signal-to-noise ratio of 30 (under a requirement to detect 95% of single events). Importance of the signal-to-noise ratio, correct finding of the signal start and choice of an appropriate sampling frequency are discussed.

ShellFit: Reconstruction in the MiniCLEAN Detector

NASA Astrophysics Data System (ADS)

Seibert, Stanley

2010-02-01

The MiniCLEAN dark matter experiment is an ultra-low background liquid cryogen detector with a fiducial volume of approximately 150 kg. Dark matter candidate events produce ultraviolet scintillation light in argon at 128 nm and in neon at 80 nm. In order to detect this scintillation light, the target volume is enclosed by acrylic plates forming a spherical shell upon which an organic fluor, tetraphenyl butadiene (TPB), has been applied. TPB absorbs UV light and reemits visible light isotropically which can be detected by photomultiplier tubes. Two significant sources of background events in MiniCLEAN are decays of radon daughters embedded in the acrylic surface and external sources of neutrons, such as the photomultiplier tubes themselves. Both of these backgrounds can be mitigated by reconstructing the origin of the scintillation light and cutting events beyond a particular radius. The scrambling of photon trajectories at the TPB surface makes this task very challenging. The ``ShellFit'' algorithm for reconstructing event position and energy in a detector with a spherical wavelength-shifting shell will be described. The performance of ShellFit will be demonstrated using Monte Carlo simulation of several event types in the MiniCLEAN detector. )

LENS: Light Transport

NASA Astrophysics Data System (ADS)

Yokley, Zachary

2013-04-01

The LENS detector uses an optically segmented 3D lattice, a scintillation lattice (SL), that channels light via total internal reflection from a scintillation event down channels parallel to the 3 primary Cartesian axes to the edge of the detector. This unique design provides spatial and temporal resolution required to distinguish the internal background of ^115In from the neutrino signal. Optical segmentation is achieved with Teflon films. Currently a 400 liter prototype, miniLENS, is being developed to demonstrate the internal background rejection techniques needed for LENS. This requires that miniLENS be shielded from external backgrounds from the surrounding materials and the photomultiplier tubes (PMTs). This shielding is provided by a water tank that surrounds miniLENS. In order to retain the channel information and separate the PMTs from the detector the LENS collaboration has developed light guides (LGs) made from multilayer films. These LGs transport light both by total internal and specular reflection providing an efficient means of coupling the SL through the water shield to the PMTs outside the water tank. This talk will discuss light transport in the SL as well as the design and construction of the LGs in the context of miniLENS.

Extragalactic background light measurements and applications.

PubMed

Cooray, Asantha

2016-03-01

This review covers the measurements related to the extragalactic background light intensity from γ-rays to radio in the electromagnetic spectrum over 20 decades in wavelength. The cosmic microwave background (CMB) remains the best measured spectrum with an accuracy better than 1%. The measurements related to the cosmic optical background (COB), centred at 1 μm, are impacted by the large zodiacal light associated with interplanetary dust in the inner Solar System. The best measurements of COB come from an indirect technique involving γ-ray spectra of bright blazars with an absorption feature resulting from pair-production off of COB photons. The cosmic infrared background (CIB) peaking at around 100 μm established an energetically important background with an intensity comparable to the optical background. This discovery paved the way for large aperture far-infrared and sub-millimetre observations resulting in the discovery of dusty, starbursting galaxies. Their role in galaxy formation and evolution remains an active area of research in modern-day astrophysics. The extreme UV (EUV) background remains mostly unexplored and will be a challenge to measure due to the high Galactic background and absorption of extragalactic photons by the intergalactic medium at these EUV/soft X-ray energies. We also summarize our understanding of the spatial anisotropies and angular power spectra of intensity fluctuations. We motivate a precise direct measurement of the COB between 0.1 and 5 μm using a small aperture telescope observing either from the outer Solar System, at distances of 5 AU or more, or out of the ecliptic plane. Other future applications include improving our understanding of the background at TeV energies and spectral distortions of CMB and CIB.

Extragalactic background light measurements and applications

PubMed Central

Cooray, Asantha

2016-01-01

This review covers the measurements related to the extragalactic background light intensity from γ-rays to radio in the electromagnetic spectrum over 20 decades in wavelength. The cosmic microwave background (CMB) remains the best measured spectrum with an accuracy better than 1%. The measurements related to the cosmic optical background (COB), centred at 1 μm, are impacted by the large zodiacal light associated with interplanetary dust in the inner Solar System. The best measurements of COB come from an indirect technique involving γ-ray spectra of bright blazars with an absorption feature resulting from pair-production off of COB photons. The cosmic infrared background (CIB) peaking at around 100 μm established an energetically important background with an intensity comparable to the optical background. This discovery paved the way for large aperture far-infrared and sub-millimetre observations resulting in the discovery of dusty, starbursting galaxies. Their role in galaxy formation and evolution remains an active area of research in modern-day astrophysics. The extreme UV (EUV) background remains mostly unexplored and will be a challenge to measure due to the high Galactic background and absorption of extragalactic photons by the intergalactic medium at these EUV/soft X-ray energies. We also summarize our understanding of the spatial anisotropies and angular power spectra of intensity fluctuations. We motivate a precise direct measurement of the COB between 0.1 and 5 μm using a small aperture telescope observing either from the outer Solar System, at distances of 5 AU or more, or out of the ecliptic plane. Other future applications include improving our understanding of the background at TeV energies and spectral distortions of CMB and CIB. PMID:27069645

75 FR 12172 - Notice of Availability of a Draft Response to Petitions for the Reclassification of Light Brown...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-15

...] Notice of Availability of a Draft Response to Petitions for the Reclassification of Light Brown Apple... two petitions we received requesting the reclassification of light brown apple moth [Epiphyas.... SUPPLEMENTARY INFORMATION: Background Light brown apple moth (Epiphyas postvittana [Walker]) (LBAM) is a plant...

Human circadian pacemaker is sensitive to light throughout subjective day without evidence of transients

NASA Technical Reports Server (NTRS)

Jewett, M. E.; Rimmer, D. W.; Duffy, J. F.; Klerman, E. B.; Kronauer, R. E.; Czeisler, C. A.

1997-01-01

Fifty-six resetting trials were conducted across the subjective day in 43 young men using a three-cycle bright-light (approximately 10,000 lx). The phase-response curve (PRC) to these trials was assessed for the presence of a "dead zone" of photic insensitivity and was compared with another three-cycle PRC that had used a background of approximately 150 lx. To assess possible transients after the light stimulus, the trials were divided into 43 steady-state trials, which occurred after several baseline days, and 13 consecutive trials, which occurred immediately after a previous resetting trial. We found that 1) bright light induces phase shifts throughout subjective day with no apparent dead zone; 2) there is no evidence of transients in constant routine assessments of the fitted temperature minimum 1-2 days after completion of the resetting stimulus; and 3) the timing of background room light modulates the resetting response to bright light. These data indicate that the human circadian pacemaker is sensitive to light at virtually all circadian phases, implying that the entire 24-h pattern of light exposure contributes to entrainment.

Influence of room lighting on grey-scale perception with a CRT-and a TFT monitor display.

PubMed

Haak, R; Wicht, M J; Hellmich, M; Nowak, G; Noack, M J

2002-05-01

To determine the influence of ambient lighting on grey-scale perception using a cathode-ray tube (CRT) and a thin film transistor (TFT) computer display. A cathode ray tube (Nokia XS 446) and a liquid crystal display (Panasonic LC 50S) were used at reduced room lighting (70 lux) and under conditions recommended for a dental operatory (1000 lux). Twenty-seven observers examined twice a modified SMPTE test pattern [0 to 255; 255 to 0] grey-scale values. The corresponding contrast differences were allocated to four ranges of grey levels (I: 0-63; II: 64-127; III: 128-191; IV: 192-255). The influences of monitor type, grey-scale range and illumination were evaluated by means of repeated measures analysis of variance. Detection of differences in monochromatic intensity was significantly earlier with reduced lighting (P<0.0001). When full ambient lighting was used, the TFT display was superior compared to the CRT monitor in ranges II and III (P<0.0001), whereas no differences could be detected for grey intensities between 0 and 63 (P=0.71) and between 192 and 255 (P=0.36). Background lighting hampers grey-scale perception on computer displays. In this study of one TFT and one CRT monitor, the TFT in full ambient lighting was associated with earlier detection of grey scale differences than CRT.

Baseline measurements of ethene in 2002: Implications for increased ethanol use and biomass burning on air quality and ecosystems

NASA Astrophysics Data System (ADS)

Gaffney, Jeffrey S.; Marley, Nancy A.; Blake, Donald R.

2012-09-01

While it is well known that combustion of ethanol as a biofuel will lead to enhanced emissions of methane, ethene (ethylene), acetaldehyde, formaldehyde, and oxides of nitrogen (primarily NO) when compared to gasoline alone, especially during cold starts or if catalytic converters are not operating properly, the impacts of increases in atmospheric ethene levels from combustion of fuels with higher ethanol content has not received much attention. Ethene is a well known and potent plant growth hormone and exposure to agricultural crops and natural vegetation results in yield reductions especially when combined with higher levels of PAN and ozone also expected from the increased use of ethanol/gasoline blends. We report here some baseline measurements of ethene obtained in 2002 in the southwestern and south central United States. These data indicate that current ethene background levels are less than 1 ppb. Anticipated increases in fuel ethanol content of E30 or greater is expected to lead to higher atmospheric levels of ethene on regional scales due to its atmospheric lifetime of 1.5-3 days. These background measurements are discussed in light of the potential enhancement of ethene levels expected from the anticipated increases in ethanol use as a renewable biofuel.

Temporal intensity interferometry for characterization of very narrow spectral lines

NASA Astrophysics Data System (ADS)

Tan, P. K.; Kurtsiefer, C.

2017-08-01

Some stellar objects exhibit very narrow spectral lines in the visible range additional to their blackbody radiation. Natural lasing has been suggested as a mechanism to explain narrow lines in Wolf-Rayet stars. However, the spectral resolution of conventional astronomical spectrographs is still about two orders of magnitude too low to test this hypothesis. We want to resolve the linewidth of narrow spectral emissions in starlight. A combination of spectral filtering with single-photon-level temporal correlation measurements breaks the resolution limit of wavelength-dispersing spectrographs by moving the linewidth measurement into the time domain. We demonstrate in a laboratory experiment that temporal intensity interferometry can determine a 20-MHz-wide linewidth of Doppler-broadened laser light and identify a coherent laser light contribution in a blackbody radiation background.

Preliminary evidence that light through the eyelids can suppress melatonin and phase shift dim light melatonin onset

PubMed Central

2012-01-01

Background A previous study reported a method for measuring the spectral transmittance of individual human eyelids. A prototype light mask using narrow-band “green” light (λmax = 527 nm) was used to deliver light through closed eyelids in two within-subjects studies. The first study investigated whether an individual-specific light dose could suppress melatonin by 40% through the closed eyelid without disrupting sleep. The light doses were delivered at three times during the night: 1) beginning (while subjects were awake), 2) middle (during rapid eye movement (REM) sleep), and 3) end (during non-REM sleep). The second study investigated whether two individual-specific light doses expected to suppress melatonin by 30% and 60% and delivered through subjects’ closed eyelids before the time of their predicted minimum core body temperature would phase delay the timing of their dim light melatonin onset (DLMO). Findings Compared to a dark control night, light delivered through eyelids suppressed melatonin by 36% (p = 0.01) after 60-minute light exposure at the beginning, 45% (p = 0.01) at the middle, and 56% (p < 0.0001) at the end of the night. In the second study, compared to a dark control night, melatonin was suppressed by 25% (p = 0.03) and by 45% (p = 0.009) and circadian phase, as measured by DLMO, was delayed by 17 minutes (p = 0.03) and 71 minutes (ns) after 60-minute exposures to light levels 1 and 2, respectively. Conclusions These studies demonstrate that individual-specific doses of light delivered through closed eyelids can suppress melatonin and phase shift DLMO and may be used to treat circadian sleep disorders. PMID:22564396

Immediate effect of blue-enhanced light on reproductive hormones in women.

PubMed

Danilenko, Konstantin V; Sergeeva, Oksana Y

2015-01-01

Light is known to stimulate reproductive function in women. We here investigated the immediate effect of light on reproductive hormones, addressing the role of blue-sensitive (~480 nm) melanopsin-based photoreception mediating the non-visual effects of light. Sixteen healthy women attended the Institute at ~07:25 (shortly after waking; sunglasses worn) twice in 2-3 days in April-May, within days 4-10 of their menstrual cycle. During one session, a broad-spectrum white-appearing light with a superimposed peak at 469 nm was presented against 5-10 lux background; during the other session, short-spectrum red light peaked at 651 nm with similar irradiance level (~7.0 W/m², corresponds to ~1200 lux) was used. Venous blood was taken at 0, 22 and 44 minutes of light exposure to measure concentrations of follicle-stimulating hormone (FSH), luteinising hormone (LH), prolactin, estradiol, progesterone and cortisol, and saliva was sampled to measure melatonin as a recognised indicator of the spectral-specific action of light. Melatonin values, as expected, were lower with white vs. red light (p=0.014), with the greatest difference at 22 minutes. Of the other hormones, only FSH concentrations differed significantly: they were mildly higher at white vs. red light (again, at 22 minutes; p=0.030; statistical analysis adjusted for menstrual cycle day and posture change [pre-sampling time seated]). Moderately bright blue-enhanced white light, compared to matched-by-irradiance red light, transiently (within 22 minutes) and mildly stimulated morning secretion of follicle-stimulating hormone in women in mid-to-late follicular phase of their menstrual cycle suggesting a direct functional link between the light and reproductive system.

What is the most prominent factor limiting photosynthesis in different layers of a greenhouse cucumber canopy?

PubMed Central

Chen, Tsu-Wei; Henke, Michael; de Visser, Pieter H. B.; Buck-Sorlin, Gerhard; Wiechers, Dirk; Kahlen, Katrin; Stützel, Hartmut

2014-01-01

Background and Aims Maximizing photosynthesis at the canopy level is important for enhancing crop yield, and this requires insights into the limiting factors of photosynthesis. Using greenhouse cucumber (Cucumis sativus) as an example, this study provides a novel approach to quantify different components of photosynthetic limitations at the leaf level and to upscale these limitations to different canopy layers and the whole plant. Methods A static virtual three-dimensional canopy structure was constructed using digitized plant data in GroIMP. Light interception of the leaves was simulated by a ray-tracer and used to compute leaf photosynthesis. Different components of photosynthetic limitations, namely stomatal (SL), mesophyll (ML), biochemical (BL) and light (LL) limitations, were calculated by a quantitative limitation analysis of photosynthesis under different light regimes. Key Results In the virtual cucumber canopy, BL and LL were the most prominent factors limiting whole-plant photosynthesis. Diffusional limitations (SL + ML) contributed <15 % to total limitation. Photosynthesis in the lower canopy was more limited by the biochemical capacity, and the upper canopy was more sensitive to light than other canopy parts. Although leaves in the upper canopy received more light, their photosynthesis was more light restricted than in the leaves of the lower canopy, especially when the light condition above the canopy was poor. An increase in whole-plant photosynthesis under diffuse light did not result from an improvement of light use efficiency but from an increase in light interception. Diffuse light increased the photosynthesis of leaves that were directly shaded by other leaves in the canopy by up to 55 %. Conclusions Based on the results, maintaining biochemical capacity of the middle–lower canopy and increasing the leaf area of the upper canopy would be promising strategies to improve canopy photosynthesis in a high-wire cucumber cropping system. Further analyses using the approach described in this study can be expected to provide insights into the influences of horticultural practices on canopy photosynthesis and the design of optimal crop canopies. PMID:24907313

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.

Novel ray tracing method for stray light suppression from ocean remote sensing measurements.

PubMed

Oh, Eunsong; Hong, Jinsuk; Kim, Sug-Whan; Park, Young-Je; Cho, Seong-Ick

2016-05-16

We developed a new integrated ray tracing (IRT) technique to analyze the stray light effect in remotely sensed images. Images acquired with the Geostationary Ocean Color Imager show a radiance level discrepancy at the slot boundary, which is suspected to be a stray light effect. To determine its cause, we developed and adjusted a novel in-orbit stray light analysis method, which consists of three simulated phases (source, target, and instrument). Each phase simulation was performed in a way that used ray information generated from the Sun and reaching the instrument detector plane efficiently. This simulation scheme enabled the construction of the real environment from the remote sensing data, with a focus on realistic phenomena. In the results, even in a cloud-free environment, a background stray light pattern was identified at the bottom of each slot. Variations in the stray light effect and its pattern according to bright target movement were simulated, with a maximum stray light ratio of 8.5841% in band 2 images. To verify the proposed method and simulation results, we compared the results with the real acquired remotely sensed image. In addition, after correcting for abnormal phenomena in specific cases, we confirmed that the stray light ratio decreased from 2.38% to 1.02% in a band 6 case, and from 1.09% to 0.35% in a band 8 case. IRT-based stray light analysis enabled clear determination of the stray light path and candidates in in-orbit circumstances, and the correction process aided recovery of the radiometric discrepancy.

Experimental methods in aquatic respirometry: the importance of mixing devices and accounting for background respiration.

PubMed

Rodgers, G G; Tenzing, P; Clark, T D

2016-01-01

In light of an increasing trend in fish biology towards using static respirometry techniques without the inclusion of a mixing mechanism and without accurately accounting for the influence of microbial (background) respiration, this paper quantifies the effect of these approaches on the oxygen consumption rates (ṀO2 ) measured from juvenile barramundi Lates calcarifer (mean ± s.e. mass = 20·31 ± 0·81 g) and adult spiny chromis damselfish Acanthochromis polyacanthus (22·03 ± 2·53 g). Background respiration changed consistently and in a sigmoidal manner over time in the treatment with a mixing device (inline recirculation pump), whereas attempts to measure background respiration in the non-mixed treatment yielded highly variable estimates of ṀO2 that were probably artefacts due to the lack of water movement over the oxygen sensor during measurement periods. This had clear consequences when accounting for background respiration in the calculations of fish ṀO2 . Exclusion of a mixing device caused a significantly lower estimate of ṀO2 in both species and reduced the capacity to detect differences between individuals as well as differences within an individual over time. There was evidence to suggest that the magnitude of these effects was dependent on the spontaneous activity levels of the fish, as the difference between mixed and non-mixed treatments was more pronounced for L. calcarifer (sedentary) than for A. polyacanthus (more spontaneously active). It is clear that respirometry set-ups for sedentary species must contain a mixing device to prevent oxygen stratification inside the respirometer. While more active species may provide a higher level of water mixing during respirometry measurements and theoretically reduce the need for a mixing device, the level of mixing cannot be quantified and may change with diurnal cycles in activity. To ensure consistency across studies without relying on fish activity levels, and to enable accurate assessments of background respiration, it is recommended that all respirometry systems should include an appropriate mixing device. © 2016 The Fisheries Society of the British Isles.

Suppression of sun interference in the star sensor baffling stray light by total internal reflection

NASA Astrophysics Data System (ADS)

Kawano, Hiroyuki; Shimoji, Haruhiko; Yoshikawa, Shoji; Miyatake, Katsumasa; Hama, Kazumori; Nakamura, Shuji

2005-09-01

We have developed a star sensor as an experimental device onboard the SERVIS-1 satellite launched in October 2003. The in-orbit data have verified its fundamental performance. One of the advantages of our star sensor is that the baffle has a small length of 120 mm instead of 182 mm in the conventional two-stage baffle design. The key concepts for light shielding are total internal reflection phenomena inside a nearly half sphere (NHS) lens and scattering light control by gloss black paint. However, undesirable background noise by the sun outside of the field of view (FOV) was observed in the corner of the FOV in the orbital experiment. Ray trace simulations revealed that slight scattering light on the specular baffle wall entered the NHS lens and reached the corner of the image sensor through the multi-reflection path inside the lens. It was found that the stray light path can be shielded effectively if the diameter of the aperture under the NHS lens was reduced. We redesigned the baffle and evaluated the light shielding ability with our sun interference test facility on the ground, and confirmed that the stray light was reduced below the acceptable level. As a result, the light shielding technique which we have proposed was proved to be effective for a small-size baffle. The redesigned star sensor is planned to be installed as a main attitude sensor for the SERVIS-2 satellite scheduled to be launched in February 2008.

Light in Thermal Environments (LITE) Workshop

NASA Technical Reports Server (NTRS)

1993-01-01

Light emitted from high temperature black smokers (350 C) at mid-ocean ridge spreading centers has been documented, but the source of this light and its photochemical and biological consequences have yet to be investigated. Preliminary studies indicate that thermal radiation alone might account for the 'glow' and that a novel photoreceptor in shrimp colonizing black smoker chimneys may detect this 'glow.' A more controversial question is whether there may be sufficient photon flux of appropriate wavelengths to support geothermally-driven photosynthesis (GDP) by microorganisms. Although only a very low level of visible and near infrared light may be emitted from any single hydrothermal vent, several aspects of the light make it of more than enigmatic interest. First, the light is clearly linked to geophysical (and perhaps geochemical) processes; its attributes may serve as powerful index parameters for monitoring change in these processes. Second, while the glow at a vent orifice is a very local phenomenon, more expansive subsurface environments may be illuminated, thereby increasing the spatial scale at which biological consequences of this light might be considered. Third, in contrast to intermittent bioluminescent light sources in the deep sea, the light emitted at vents almost certainly glows or flickers continuously over the life of the individual black smokers (years to decades); collectively, light emitted from black smokers along the ocean's spreading centers superimposed on background Cerenkov radiation negates the concept of the deep sea as an environment devoid of abiotic light. Finally, the history of hydrothermal activity predates the origin of life; light in the deep sea has been a continuous phenomenon on a geological time scale and may have served either as a seed or refugium for the evolution of biological photochemical reactions or adaptations.

46 CFR 113.25-10 - Emergency red-flashing lights.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Emergency red-flashing lights. 113.25-10 Section 113.25... lights. (a) In a space described in § 113.25-9(a), where the general emergency alarm signal cannot be heard over the background noise, there must be a red-flashing light or rotating beacon, in addition to...

46 CFR 113.25-10 - Emergency red-flashing lights.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 false Emergency red-flashing lights. 113.25-10 Section 113.25... lights. (a) In a space described in § 113.25-9(a), where the general emergency alarm signal cannot be heard over the background noise, there must be a red-flashing light or rotating beacon, in addition to...

7. INTERIOR LIVING ROOM SHOWING 6LIGHT FRONT DOOR FLANKED BY ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. INTERIOR LIVING ROOM SHOWING 6-LIGHT FRONT DOOR FLANKED BY ONE OF TWO 6-LIGHT OVER 1-LIGHT SASH WINDOWS AT PHOTO RIGHT, AND OPEN DOORWAY TO BEDROOM NUMBER ONE (AND BEDROOM NUMBER TWO IN BACKGROUND) AT PHOTO LEFT. VIEW TO NORTH. - Rush Creek Hydroelectric System, Worker Cottage, Rush Creek, June Lake, Mono County, CA

46 CFR 113.25-10 - Emergency red-flashing lights.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Emergency red-flashing lights. 113.25-10 Section 113.25... lights. (a) In a space described in § 113.25-9(a), where the general emergency alarm signal cannot be heard over the background noise, there must be a red-flashing light or rotating beacon, in addition to...

46 CFR 113.25-10 - Emergency red-flashing lights.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 false Emergency red-flashing lights. 113.25-10 Section 113.25... lights. (a) In a space described in § 113.25-9(a), where the general emergency alarm signal cannot be heard over the background noise, there must be a red-flashing light or rotating beacon, in addition to...

46 CFR 113.25-10 - Emergency red-flashing lights.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 false Emergency red-flashing lights. 113.25-10 Section 113.25... lights. (a) In a space described in § 113.25-9(a), where the general emergency alarm signal cannot be heard over the background noise, there must be a red-flashing light or rotating beacon, in addition to...

Background starlight observed from Pioneer 10. [beyond asteroid belt

NASA Technical Reports Server (NTRS)

Weinberg, J. L.; Hanner, M. S.; Beeson, D. E.; Deshields, L. M., II; Green, B. A.

1974-01-01

The results of background starlight observations are reviewed that were obtained by the Pioneer 10 asteroid-Jupiter probe when, after passage beyond the asteroid belt, its imaging photopolarimeter observed integrated starlight and diffuse galactic light for the first time in the absence of zodiacal light. Brightnesses in the blue are presented with and without individually resolved stars for regions of the sky observed when Pioneer 10 was 4.64 astronomical units from the sun.

Chronic Artificial Blue-Enriched White Light Is an Effective Countermeasure to Delayed Circadian Phase and Neurobehavioral Decrements

PubMed Central

Najjar, Raymond P.; Wolf, Luzian; Taillard, Jacques; Schlangen, Luc J. M.; Salam, Alex

2014-01-01

Studies in Polar Base stations, where personnel have no access to sunlight during winter, have reported circadian misalignment, free-running of the sleep-wake rhythm, and sleep problems. Here we tested light as a countermeasure to circadian misalignment in personnel of the Concordia Polar Base station during the polar winter. We hypothesized that entrainment of the circadian pacemaker to a 24-h light-dark schedule would not occur in all crew members (n = 10) exposed to 100–300 lux of standard fluorescent white (SW) light during the daytime, and that chronic non-time restricted daytime exposure to melanopsin-optimized blue-enriched white (BE) light would establish an a stable circadian phase, in participants, together with increased cognitive performance and mood levels. The lighting schedule consisted of an alternation between SW lighting (2 weeks), followed by a BE lighting (2 weeks) for a total of 9 weeks. Rest-activity cycles assessed by actigraphy showed a stable rest-activity pattern under both SW and BE light. No difference was found between light conditions on the intra-daily stability, variability and amplitude of activity, as assessed by non-parametric circadian analysis. As hypothesized, a significant delay of about 30 minutes in the onset of melatonin secretion occurred with SW, but not with BE light. BE light significantly enhanced well being and alertness compared to SW light. We propose that the superior efficacy of blue-enriched white light versus standard white light involves melanopsin-based mechanisms in the activation of the non-visual functions studied, and that their responses do not dampen with time (over 9-weeks). This work could lead to practical applications of light exposure in working environment where background light intensity is chronically low to moderate (polar base stations, power plants, space missions, etc.), and may help design lighting strategies to maintain health, productivity, and personnel safety. PMID:25072880

Average expansion rate and light propagation in a cosmological Tardis spacetime

NASA Astrophysics Data System (ADS)

Lavinto, Mikko; Räsänen, Syksy; Szybka, Sebastian J.

2013-12-01

We construct the first exact statistically homogeneous and isotropic cosmological solution in which inhomogeneity has a significant effect on the expansion rate. The universe is modelled as a Swiss Cheese, with dust FRW background and inhomogeneous holes. We show that if the holes are described by the quasispherical Szekeres solution, their average expansion rate is close to the background under certain rather general conditions. We specialise to spherically symmetric holes and violate one of these conditions. As a result, the average expansion rate at late times grows relative to the background, ie backreaction is significant. The holes fit smoothly into the background, but are larger on the inside than a corresponding background domain: we call them Tardis regions. We study light propagation, find the effective equations of state and consider the relation of the spatially averaged expansion rate to the redshift and the angular diameter distance.

Constraints on dark matter from intergalactic radiation

NASA Technical Reports Server (NTRS)

Overduin, J. M.; Wesson, P. S.

1992-01-01

Several of the dark matter candidates that have been proposed are believed to be unstable to decay, which would contribute photons to the radiation field between galaxies. The main candidates of this type are light neutrinos and axions, primordial mini-black holes, and a nonzero 'vacuum' energy. All of these can be constrained in nature by observational data on the extragalactic background light and the microwave background radiation. Black holes and the vacuum can be ruled out as significant contributors to the 'missing mass'. Light axions are also unlikely candidates; however, those with extremely small rest energies (the so-called 'invisible' axions) remain feasible. Light neutrinos, like those proposed by Sciama, are marginally viable. In general, we believe that the intergalactic radiation field is an important way of constraining all types of dark matter.

Study of light backgrounds from relativistic electrons in air light-guides

NASA Astrophysics Data System (ADS)

Riordan, S.; Zhao, Y. X.; Baunack, S.; Becker, D.; Clarke, C.; Dehmelt, K.; Deshpande, A.; Gericke, M.; Gläser, B.; Imai, K.; Kutz, T.; Maas, F. E.; McNulty, D.; Pan, J.; Park, S.; Rahman, S.; Souder, P. A.; Wang, P.; Wellman, B.; Kumar, K. S.

2018-07-01

The MOLLER experiment proposed at the Thomas Jefferson National Accelerator Facility plans a precision low energy determination of the weak mixing angle via the measurement of the parity-violating asymmetry in the scattering of high energy longitudinally polarized electrons from electrons bound in a liquid hydrogen target (Møller scattering). A relative measure of the scattering rate is planned to be obtained by intercepting the Møller scattered electrons with a circular array of thin fused silica tiles attached to air light guides, which facilitate the transport of Cherenkov photons generated within the tiles to photomultiplier tubes (PMTs). The scattered flux will also pass through the light guides of downstream tiles, generating additional Cherenkov as well as scintillation light and is a potential background. In order to estimate the rate of these backgrounds, a gas-filled tube detector was designed and deployed in an electron beam at the MAMI facility at Johannes Gutenberg University, Mainz, Germany. Described in this paper is the design of a detector to measure separately the scintillation and Cherenkov responses of gas mixtures from relativistic electrons, the results of studies of several gas mixtures with comparisons to simulations, and conclusions about the implications for the design of the MOLLER detector apparatus.

Serum Free Light Chains in Neoplastic Monoclonal Gammopathies: Relative Under-Detection of Lambda Dominant Kappa/Lambda Ratio, and Underproduction of Free Lambda Light Chains, as Compared to Kappa Light Chains, in Patients With Neoplastic Monoclonal Gammopathies

PubMed Central

Lee, Won Sok; Singh, Gurmukh

2018-01-01

Background Quantitative evaluation of serum free light chains is recommended for the work up of monoclonal gammopathies. Immunoglobulin light chains are generally produced in excess of heavy chains. In patients with monoclonal gammopathy, κ/λ ratio is abnormal less frequently with lambda chain lesions. This study was undertaken to ascertain if the levels of overproduction of the two light chain types and their detection rates are different in patients with neoplastic monoclonal gammopathies. Methods Results of serum protein electrophoresis (SPEP), serum protein immunofixation electrophoresis (SIFE), urine protein electrophoresis (UPEP), urine protein immunofixation electrophoresis (UIFE), and serum free light chain assay (SFLCA) in patients with monoclonal gammopathies were examined retrospectively. Results The κ/λ ratios were appropriately abnormal more often in kappa chain lesions. Ratios of κ/λ were normal in about 25% of patients with lambda chain lesions in whom free homogenous lambda light chains were detectable in urine. An illustrative case suggests underproduction of free lambda light chains, in some instances. Conclusions The lower prevalence of lambda dominant κ/λ ratio in lesions with lambda light chains is estimated to be due to relative under-detection of lambda dominant κ/λ ratio in about 25% of the patients and because lambda chains are not produced in as much excess of heavy chains as are kappa chains, in about 5% of the patients. The results question the medical necessity and clinical usefulness of the serum free light chain assay. UPEP/UIFE is under-utilized. PMID:29904440

Light at Night and Breast Cancer Risk Among California Teachers

PubMed Central

Hurley, Susan; Goldberg, Debbie; Nelson, David; Hertz, Andrew; Horn-Ross, Pamela L.; Bernstein, Leslie; Reynolds, Peggy

2014-01-01

Background There is convincing evidence that circadian disruption mediated by exposure to light at night promotes mammary carcinogenesis in rodents. The role that light at night plays in human breast cancer etiology remains unknown. We evaluated the relationship between estimates of indoor and outdoor light at night and the risk of breast cancer among members of the California Teachers Study. Methods Indoor light-at-night estimates were based on questionnaire data regarding sleep habits and use of night time lighting while sleeping. Estimates of outdoor light at night were derived from imagery data obtained from the U.S. Defense Meteorological Satellite Program assigned to geocoded addresses of study participants. Analyses were conducted among 106,731 California Teachers Study members who lived in California, had no prior history of breast cancer, and provided information on lighting while sleeping. 5,095 cases of invasive breast cancer diagnosed 1995–2010 were identified via linkage to the California Cancer Registry. We used age-stratified Cox proportional hazard models to calculate hazard ratios (HRs) with 95% confidence intervals (CIs), adjusting for breast cancer risk factors and neighborhood urbanization and socioeconomic class. Results An increased risk was found for women living in areas with the highest quintile of outdoor light at night exposure estimates (HR=1.12 [95% CI=1.00 – 1.26], test for trend, P=0.06). While more pronounced among premenopausal women (HR=1.34 [95% CI=1.07 – 1.69], test for trend, P=0.04), the associations did not differ statistically by menopausal status (test for interaction, P=0.34). Conclusions Women living in areas with high levels of ambient light at night may be at an increased risk of breast cancer. Future studies that integrate quantitative measurements of indoor and outdoor light at night are warranted. PMID:25061924

Pedestrian Detection Based on Adaptive Selection of Visible Light or Far-Infrared Light Camera Image by Fuzzy Inference System and Convolutional Neural Network-Based Verification.

PubMed

Kang, Jin Kyu; Hong, Hyung Gil; Park, Kang Ryoung

2017-07-08

A number of studies have been conducted to enhance the pedestrian detection accuracy of intelligent surveillance systems. However, detecting pedestrians under outdoor conditions is a challenging problem due to the varying lighting, shadows, and occlusions. In recent times, a growing number of studies have been performed on visible light camera-based pedestrian detection systems using a convolutional neural network (CNN) in order to make the pedestrian detection process more resilient to such conditions. However, visible light cameras still cannot detect pedestrians during nighttime, and are easily affected by shadows and lighting. There are many studies on CNN-based pedestrian detection through the use of far-infrared (FIR) light cameras (i.e., thermal cameras) to address such difficulties. However, when the solar radiation increases and the background temperature reaches the same level as the body temperature, it remains difficult for the FIR light camera to detect pedestrians due to the insignificant difference between the pedestrian and non-pedestrian features within the images. Researchers have been trying to solve this issue by inputting both the visible light and the FIR camera images into the CNN as the input. This, however, takes a longer time to process, and makes the system structure more complex as the CNN needs to process both camera images. This research adaptively selects a more appropriate candidate between two pedestrian images from visible light and FIR cameras based on a fuzzy inference system (FIS), and the selected candidate is verified with a CNN. Three types of databases were tested, taking into account various environmental factors using visible light and FIR cameras. The results showed that the proposed method performs better than the previously reported methods.

Status of the GERDA Phase II upgrade

NASA Astrophysics Data System (ADS)

Wagner, Victoria

2016-06-01

The GERDA experiment is designed to search for neutrinoless double beta (0νββ) decay of 76Ge. In Phase I of the experiment a background index of 10-2 cts/(keV.kg.yr) was reached. A lower limit on the half-life of the 0νββ decay of 76Ge was set to 2.1.1025 yr (at 90% C.L.). The aim of Phase II is to reach a sensitivity of the half-life of about 1026 yr. To increase the exposure thirty new Broad Energy Germanium (BEGe) detectors have been produced. These detectors are distinct for their improved energy resolution and enhanced pulse shape discrimination of signal from background events. Further background reduction will be reached by a light instrumentation to read out argon scintillation light. In April 2015 the light instrumentation together with eight BEGe detectors has been successfully deployed in the GERDA cryostat. In a commissioning run it was shown that two of the major background components, external γ-rays from 214Bi and 208Tl decays, were suppressed up to two orders of magnitude. We are confident to reach a background index of 10-3 cts/(keV.kg.yr) which is the design goal for GERDA Phase II.

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

Wagner, Victoria

The GERDA experiment is designed to search for neutrinoless double beta (0νββ) decay of {sup 76}Ge. In Phase I of the experiment a background index of 10{sup −2} cts/(keV·kg·yr) was reached. A lower limit on the half-life of the 0νββ decay of {sup 76}Ge was set to 2.1·10{sup 25} yr (at 90% C.L.). The aim of Phase II is to reach a sensitivity of the half-life of about 10{sup 26} yr. To increase the exposure thirty new Broad Energy Germanium (BEGe) detectors have been produced. These detectors are distinct for their improved energy resolution and enhanced pulse shape discrimination ofmore » signal from background events. Further background reduction will be reached by a light instrumentation to read out argon scintillation light. In April 2015 the light instrumentation together with eight BEGe detectors has been successfully deployed in the GERDA cryostat. In a commissioning run it was shown that two of the major background components, external γ-rays from {sup 214}Bi and {sup 208}Tl decays, were suppressed up to two orders of magnitude. We are confident to reach a background index of 10{sup −3} cts/(keV·kg·yr) which is the design goal for GERDA Phase II.« less

Suppression of cucumber powdery mildew by UV-B is affected by background light quality

USDA-ARS?s Scientific Manuscript database

Brief (5-10 min) exposure to UV-B radiation (280-300 nm) suppressed powdery mildew (Podosphaera xanthii) on Cucumis sativus. The effect was enhanced by red light (600-660 nm), but offset by blue light (420-500 nm) and UV-A (300-420 nm). Compared to untreated controls, 2 h red light from specific lig...

Arabidopsis plants grown in the field and climate chambers significantly differ in leaf morphology and photosystem components

PubMed Central

2012-01-01

Background Plants exhibit phenotypic plasticity and respond to differences in environmental conditions by acclimation. We have systematically compared leaves of Arabidopsis thaliana plants grown in the field and under controlled low, normal and high light conditions in the laboratory to determine their most prominent phenotypic differences. Results Compared to plants grown under field conditions, the "indoor plants" had larger leaves, modified leaf shapes and longer petioles. Their pigment composition also significantly differed; indoor plants had reduced levels of xanthophyll pigments. In addition, Lhcb1 and Lhcb2 levels were up to three times higher in the indoor plants, but differences in the PSI antenna were much smaller, with only the low-abundance Lhca5 protein showing altered levels. Both isoforms of early-light-induced protein (ELIP) were absent in the indoor plants, and they had less non-photochemical quenching (NPQ). The field-grown plants had a high capacity to perform state transitions. Plants lacking ELIPs did not have reduced growth or seed set rates, but their mortality rates were sometimes higher. NPQ levels between natural accessions grown under different conditions were not correlated. Conclusion Our results indicate that comparative analysis of field-grown plants with those grown under artificial conditions is important for a full understanding of plant plasticity and adaptation. PMID:22236032

The Effects of Dietary Carotenoid Supplementation and Retinal Carotenoid Accumulation on Vision-Mediated Foraging in the House Finch

PubMed Central

Toomey, Matthew B.; McGraw, Kevin J.

2011-01-01

Background For many bird species, vision is the primary sensory modality used to locate and assess food items. The health and spectral sensitivities of the avian visual system are influenced by diet-derived carotenoid pigments that accumulate in the retina. Among wild House Finches (Carpodacus mexicanus), we have found that retinal carotenoid accumulation varies significantly among individuals and is related to dietary carotenoid intake. If diet-induced changes in retinal carotenoid accumulation alter spectral sensitivity, then they have the potential to affect visually mediated foraging performance. Methodology/Principal Findings In two experiments, we measured foraging performance of house finches with dietarily manipulated retinal carotenoid levels. We tested each bird's ability to extract visually contrasting food items from a matrix of inedible distracters under high-contrast (full) and dimmer low-contrast (red-filtered) lighting conditions. In experiment one, zeaxanthin-supplemented birds had significantly increased retinal carotenoid levels, but declined in foraging performance in the high-contrast condition relative to astaxanthin-supplemented birds that showed no change in retinal carotenoid accumulation. In experiments one and two combined, we found that retinal carotenoid concentrations predicted relative foraging performance in the low- vs. high-contrast light conditions in a curvilinear pattern. Performance was positively correlated with retinal carotenoid accumulation among birds with low to medium levels of accumulation (∼0.5–1.5 µg/retina), but declined among birds with very high levels (>2.0 µg/retina). Conclusion/Significance Our results suggest that carotenoid-mediated spectral filtering enhances color discrimination, but that this improvement is traded off against a reduction in sensitivity that can compromise visual discrimination. Thus, retinal carotenoid levels may be optimized to meet the visual demands of specific behavioral tasks and light environments. PMID:21747917

Physical Activity Level and Sedentary Behaviors among Public School Children in Dakar (Senegal) Measured by PAQ-C and Accelerometer: Preliminary Results

PubMed Central

Diouf, Adama; Thiam, Mbeugué; Idohou-Dossou, Nicole; Diongue, Ousmane; Mégné, Ndé; Diallo, Khady; Sembène, Pape Malick; Wade, Salimata

2016-01-01

Background: Physical inactivity and sedentary lifestyles are major risk factors of childhood obesity. This study aimed to measure physical activity (PA) levels by accelerometer and Physical Activity Questionnaire for Older Children (PAQ-C) among Senegalese school children and the relation with Body Mass Index (BMI) and body composition. Methodology: 156 pupils 8–11 years old were randomly selected in four elementary public schools of Dakar. BMI z-score was used to categorize children according to their weight status. PA was measured by PAQ-C in the 156 pupils and by accelerometer (Actigraph GT3X+, Pensacola, FL, USA) in a subsample of 42 children. Body composition was determined by deuterium dilution method. Results: PAQ-C results were comparable in the 156 and 42 pupils. The 42 pupils presented a light activity measured by accelerometer, while PAQ-C classified the majority of them (57%; n = 24) in the moderate PA level. Children spent most of their time (min/day) in sedentary activities and light activities than in moderate and intense activity levels. Accumulation of 60 min/day Moderate-to-Vigorous Physical Activity (MVPA) was achieved by 54.8% (n = 23) of the pupils. MVPA decreased in girls in relation to their body fatness. There was a significant difference in MVPA between boys and girls. Similarly, overweight/obese (45 ± 16 min/day) children had lower MVPA than their normal and underweight peers (88 ± 34 and 74 ± 36 min/day, respectively; p = 0.004). Conclusions: The two methods are inconsistent for measuring light and moderate PA levels. Although PAQ-C is an uncomplicated routine method, various activities were not adapted for genuine activities in Senegalese children and therefore needs to be validated in African children. PMID:27735876

Physical Activity Level and Sedentary Behaviors among Public School Children in Dakar (Senegal) Measured by PAQ-C and Accelerometer: Preliminary Results.

PubMed

Diouf, Adama; Thiam, Mbeugué; Idohou-Dossou, Nicole; Diongue, Ousmane; Mégné, Ndé; Diallo, Khady; Sembène, Pape Malick; Wade, Salimata

2016-10-10

Background : Physical inactivity and sedentary lifestyles are major risk factors of childhood obesity. This study aimed to measure physical activity (PA) levels by accelerometer and Physical Activity Questionnaire for Older Children (PAQ-C) among Senegalese school children and the relation with Body Mass Index (BMI) and body composition. Methodology : 156 pupils 8-11 years old were randomly selected in four elementary public schools of Dakar. BMI z -score was used to categorize children according to their weight status. PA was measured by PAQ-C in the 156 pupils and by accelerometer (Actigraph GT3X+, Pensacola, FL, USA) in a subsample of 42 children. Body composition was determined by deuterium dilution method. Results : PAQ-C results were comparable in the 156 and 42 pupils. The 42 pupils presented a light activity measured by accelerometer, while PAQ-C classified the majority of them (57%; n = 24) in the moderate PA level. Children spent most of their time (min/day) in sedentary activities and light activities than in moderate and intense activity levels. Accumulation of 60 min/day Moderate-to-Vigorous Physical Activity (MVPA) was achieved by 54.8% ( n = 23) of the pupils. MVPA decreased in girls in relation to their body fatness. There was a significant difference in MVPA between boys and girls. Similarly, overweight/obese (45 ± 16 min/day) children had lower MVPA than their normal and underweight peers (88 ± 34 and 74 ± 36 min/day, respectively; p = 0.004). Conclusions : The two methods are inconsistent for measuring light and moderate PA levels. Although PAQ-C is an uncomplicated routine method, various activities were not adapted for genuine activities in Senegalese children and therefore needs to be validated in African children.

Evaluation of Four Different Restorative Materials for Restoration of the Periodontal Condition of Wedge-Shaped Defect: A Comparative Study.

PubMed

Ruan, Jian-Yong; Gong, Zheng-Lin; Zhang, Rui-Zhi; Zhang, Zhe; Xu, Ran; Li, Da-Xu; Ren, Le; Tao, Hong

2017-09-16

BACKGROUND This study aimed to conduct a clinical evaluation of four restorative materials for restoration of dental wedge-shaped defect (WSD) and their impacts on periodontal tissues. MATERIAL AND METHODS A total of 280 maxillary premolars with dental WSD were selected from 106 patients; the patient cases were divided into eight groups according to different combinations of restorative materials (flowable resin composites, Dyract compomers, glass ionomer cement (GIC), light-curing composite resin), and WSD positions (approaching gingival and subgingival positions). Gingival crevicular fluid (GCF) volume, levels of aspartate aminotransferase (AST), alkaline phosphatase (ALP), and interleukin-1β (IL-1β) in GCF were analyzed, while probing depth (PD), plaque index (PLI), and sulcus bleeding index (SBI) were also measured. The periodontal conditions of all patients were followed prior to restoration, as well as six months and 12 months after restoration. RESULTS After six months of restoration, the overall clinical success rates of flowable resin composites, Dyract compomers, and light-curing composite resin were greater than those of GIC. GCF volume, GCF-AST, IL-1β levels, PD, PLI, and SBI of cases restored by GIC were higher than those restored by the other three materials. After 12 months of restoration, the overall clinical success rates of flowable resin composites and Dyract compomers were greater than those of light-curing composite resin and GIC. GCF volume, GCF-AST, GCF-ALP, IL-1β levels, PD, PLI, and SBI of cases restored by GIC were higher than those restored by the other three materials. CONCLUSIONS Our study provided evidence that the clinical efficacy of flowable resin composites, Dyract compomers, and light-curing composite resin was greater than that of GIC for restoration of dental WSD.

Evaluation of Four Different Restorative Materials for Restoration of the Periodontal Condition of Wedge-Shaped Defect: A Comparative Study

PubMed Central

Ruan, Jian-Yong; Gong, Zheng-Lin; Zhang, Rui-Zhi; Zhang, Zhe; Xu, Ran; Li, Da-Xu; Ren, Le; Tao, Hong

2017-01-01

Background This study aimed to conduct a clinical evaluation of four restorative materials for restoration of dental wedge-shaped defect (WSD) and their impacts on periodontal tissues. Material/Methods A total of 280 maxillary premolars with dental WSD were selected from 106 patients; the patient cases were divided into eight groups according to different combinations of restorative materials (flowable resin composites, Dyract compomers, glass ionomer cement (GIC), light-curing composite resin), and WSD positions (approaching gingival and subgingival positions). Gingival crevicular fluid (GCF) volume, levels of aspartate aminotransferase (AST), alkaline phosphatase (ALP), and interleukin-1β (IL-1β) in GCF were analyzed, while probing depth (PD), plaque index (PLI), and sulcus bleeding index (SBI) were also measured. The periodontal conditions of all patients were followed prior to restoration, as well as six months and 12 months after restoration. Results After six months of restoration, the overall clinical success rates of flowable resin composites, Dyract compomers, and light-curing composite resin were greater than those of GIC. GCF volume, GCF-AST, IL-1β levels, PD, PLI, and SBI of cases restored by GIC were higher than those restored by the other three materials. After 12 months of restoration, the overall clinical success rates of flowable resin composites and Dyract compomers were greater than those of light-curing composite resin and GIC. GCF volume, GCF-AST, GCF-ALP, IL-1β levels, PD, PLI, and SBI of cases restored by GIC were higher than those restored by the other three materials. Conclusions Our study provided evidence that the clinical efficacy of flowable resin composites, Dyract compomers, and light-curing composite resin was greater than that of GIC for restoration of dental WSD. PMID:28917087

Time-resolved laser spectroscopy of multiply ionized atoms: natural radiative lifetimes in Ce IV.

PubMed

Zhang, Z G; Svanberg, S; Quinet, P; Palmeri, P; Biémont, E

2001-12-31

Radiative lifetimes have been measured for two excited levels of Ce IV using the time-resolved laser-induced fluorescence technique. Ce3+ ions were produced in a laser-induced plasma. In the measurements, a suitable magnetic field was applied to reduce the recombination between electrons and the ions and thus the background light from the recombination, and special care was exercised to avoid flight-out-of-view effects on the lifetime measurements for the high-velocity ions. The experimental lifetime results, tau = 30(2) ns for the level 49 737 cm(-1) and tau = 30(3) ns for the level 52 226 cm(-1), were compared with relativistic Hartree-Fock calculations (tau = 30.5 and 30.0 ns) indicating a particularly excellent agreement.

Patients' Experience of Winter Depression and Light Room Treatment

PubMed Central

2017-01-01

Background. There is a need for more knowledge on the effects of light room treatment in patients with seasonal affective disorder and to explore patients' subjective experience of the disease and the treatment. Methods. This was a descriptive and explorative study applying qualitative content analysis. A purposeful sample of 18 psychiatric outpatients with a major depressive disorder with a seasonal pattern and a pretreatment score ≥12 on the 9-item Montgomery-Åsberg Depression self-rating scale was included (10 women and 8 men, aged 24–65 years). All patients had completed light room treatment (≥7/10 consecutive weekdays). Data was collected two weeks after treatment using a semistructured interview guide. Results. Patients described a clear seasonal pattern and a profound struggle to adapt to seasonal changes during the winter, including deterioration in sleep, daily rhythms, energy level, mood, activity, and cognitive functioning. Everyday life was affected with reduced work capacity, social withdrawal, and disturbed relations with family and friends. The light room treatment resulted in a radical and rapid improvement in all the major symptoms with only mild and transient side effects. Discussion. The results indicate that light room treatment is essential for some patients' ability to cope with seasonal affective disorder. PMID:28293623

Highly effective phosphorylation by G protein-coupled receptor kinase 7 of light-activated visual pigment in cones.

PubMed

Tachibanaki, Shuji; Arinobu, Daisuke; Shimauchi-Matsukawa, Yoshie; Tsushima, Sawae; Kawamura, Satoru

2005-06-28

Cone photoreceptors show briefer photoresponses than rod photoreceptors. Our previous study showed that visual pigment phosphorylation, a quenching mechanism of light-activated visual pigment, is much more rapid in cones than in rods. Here, we measured the early time course of this rapid phosphorylation with good time resolution and directly compared it with the photoresponse time course in cones. At the time of photoresponse recovery, almost two phosphates were incorporated into a bleached cone pigment molecule, which indicated that the visual pigment phosphorylation coincides with the photoresponse recovery. The rapid phosphorylation in cones is attributed to very high activity of visual pigment kinase [G protein-coupled receptor kinase (GRK) 7] in cones. Because of this high activity, cone pigment is readily phosphorylated at very high bleach levels, which probably explains why cone photoresponses recover quickly even after a very bright light and do not saturate under intense background light. The high GRK7 activity is brought about by high content of a highly potent enzyme. The expression level of GRK7 was 10 times higher than that of rod kinase (GRK1), and the specific activity of a single GRK7 molecule was approximately 10 times higher than that of GRK1. The specific activity of GRK7 is the highest among the GRKs so far known. Our result seems to explain the response characteristics of cone photoreceptors in many aspects, including the nonsaturation of the cone responses during daylight vision.

Comparison of visual acuity estimates using three different letter charts under two ambient room illuminations

PubMed Central

Chen, Ai-Hong; Norazman, Fatin Nur Najwa; Buari, Noor Halilah

2012-01-01

Background: Visual acuity is an essential estimate to assess ability of the visual system and is used as an indicator of ocular health status. Aim: The aim of this study is to investigate the consistency of acuity estimates from three different clinical visual acuity charts under two levels of ambient room illumination. Materials and Methods: This study involved thirty Malay university students aged between 19 and 23 years old (7 males, 23 females), with their spherical refractive error ranging between plano and –7.75D, astigmatism ranging from plano to –1.75D, anisometropia less than 1.00D and with no history of ocular injury or pathology. Right eye visual acuity (recorded in logMAR unit) was measured with Snellen letter chart (Snellen), wall mounted letter chart (WM) and projected letter chart (PC) under two ambient room illuminations, room light on and room light off. Results: Visual acuity estimates showed no statistically significant difference when measured with the room light on and with the room light off (F1,372 = 0.26, P = 0.61). Post-hoc analysis with Tukey showed that visual acuity estimates were significantly different between the Snellen and PC (P = 0.009) and between Snellen and WM (P = 0.002). Conclusions: Different levels of ambient room illumination had no significant effect on visual acuity estimates. However, the discrepancies in estimates of visual acuity noted in this study were purely due to the type of letter chart used. PMID:22446903

COP1, a negative regulator of photomorphogenesis, positively regulates plant disease resistance via double-stranded RNA binding proteins

PubMed Central

Lim, Gah-Hyun; Zhu, Shifeng; Clavel, Marion; Yu, Keshun; Navarre, Duroy; Kachroo, Aardra; Deragon, Jean-Marc

2018-01-01

The E3 ubiquitin ligase COP1 (Constitutive Photomorphogenesis 1) is a well known component of the light-mediated plant development that acts as a repressor of photomorphogenesis. Here we show that COP1 positively regulates defense against turnip crinkle virus (TCV) and avrRPM1 bacteria by contributing to stability of resistance (R) protein HRT and RPM1, respectively. HRT and RPM1 levels and thereby pathogen resistance is significantly reduced in the cop1 mutant background. Notably, the levels of at least two double-stranded RNA binding (DRB) proteins DRB1 and DRB4 are reduced in the cop1 mutant background suggesting that COP1 affects HRT stability via its effect on the DRB proteins. Indeed, a mutation in either drb1 or drb4 resulted in degradation of HRT. In contrast to COP1, a multi-subunit E3 ligase encoded by anaphase-promoting complex (APC) 10 negatively regulates DRB4 and TCV resistance but had no effect on DRB1 levels. We propose that COP1-mediated positive regulation of HRT is dependent on a balance between COP1 and negative regulators that target DRB1 and DRB4. PMID:29513740

Measured Radiation and Background Levels During Transmission of Megawatt Electron Beams Through Millimeter Apertures

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

Alarcon, Ricardo; Balascuta, S.; Benson, Stephen V.

2013-11-01

We report measurements of photon and neutron radiation levels observed while transmitting a 0.43 MW electron beam through millimeter-sized apertures and during beam-off, but accelerating gradient RF-on, operation. These measurements were conducted at the Free-Electron Laser (FEL) facility of the Jefferson National Accelerator Laboratory (JLab) using a 100 MeV electron beam from an energy-recovery linear accelerator. The beam was directed successively through 6 mm, 4 mm, and 2 mm diameter apertures of length 127 mm in aluminum at a maximum current of 4.3 mA (430 kW beam power). This study was conducted to characterize radiation levels for experiments that needmore » to operate in this environment, such as the proposed DarkLight Experiment. We find that sustained transmission of a 430 kW continuous-wave (CW) beam through a 2 mm aperture is feasible with manageable beam-related backgrounds. We also find that during beam-off, RF-on operation, multipactoring inside the niobium cavities of the accelerator cryomodules is the primary source of ambient radiation when the machine is tuned for 130 MeV operation.« less

Treatment of Acute Renal Failure Secondary to Multiple Myeloma with Chemotherapy and Extended High Cut-Off Hemodialysis

PubMed Central

Hutchison, Colin A.; Bradwell, Arthur R.; Cook, Mark; Basnayake, Kolitha; Basu, Supratik; Harding, Stephen; Hattersley, John; Evans, Neil D.; Chappel, Mike J.; Sampson, Paul; Foggensteiner, Lukas; Adu, Dwomoa; Cockwell, Paul

2009-01-01

Background and objectives: Extended hemodialysis using a high cut-off dialyzer (HCO-HD) removes large quantities of free light chains in patients with multiple myeloma. However, the clinical utility of this method is uncertain. This study assessed the combination of chemotherapy and HCO-HD on serum free light chain concentrations and renal recovery in patients with myeloma kidney (cast nephropathy) and dialysis-dependent acute renal failure. Design, setting, participants, & measurements: An open-label study of the relationship between free light chain levels and clinical outcomes in 19 patients treated with standard chemotherapy regimens and HCO-HD. Results: There were sustained early reductions in serum free light chain concentrations (median 85% [range 50 to 97]) in 13 patients. These 13 patients became dialysis independent at a median of 27 d (range 13 to 120). Six patients had chemotherapy interrupted because of early infections and did not achieve sustained early free light chain reductions; one of these patients recovered renal function (at 105 d) the remaining 5 patients did not recover renal function. Patients who recovered renal function had a significantly improved survival (P < 0.012). Conclusion: In dialysis-dependent acute renal failure secondary to myeloma kidney, patients who received uninterrupted chemotherapy and extended HCO-HD had sustained reductions in serum free light chain concentrations and recovered independent renal function. PMID:19339414

Sunscreen for Fish: Co-Option of UV Light Protection for Camouflage

PubMed Central

Mueller, Kaspar P.; Neuhauss, Stephan C. F.

2014-01-01

Many animals change their body pigmentation according to illumination of their environment. In aquatic vertebrates, this reaction is mediated through aggregation or dispersion of melanin-filled vesicles (melanosomes) in dermal pigment cells (melanophores). The adaptive value of this behavior is usually seen in camouflage by allowing the animal to visually blend into the background. When exposed to visible light from below, however, dark-adapted zebrafish embryos at the age of 2 days post fertilization (dpf) surprisingly display dispersal instead of aggregation of melanosomes, i.e. their body coloration becomes dark on a bright background. Melanosomes of older embryos and early larvae (3–5 dpf) on the other hand aggregate as expected under these conditions. Here we provide an explanation to this puzzling finding: Melanosome dispersion in larvae 3 dpf and older is efficiently triggered by ultraviolet (UV) light, irrespective of the visual background, suggesting that the extent of pigmentation is a trade-off between threats from predation and UV irradiation. The UV light-induced dispersion of melanosomes thereby is dependent on input from retinal short wavelength-sensitive (SWS) cone photoreceptors. In young embryos still lacking a functional retina, protection from UV light predominates, and light triggers a dispersal of melanosomes via photoreceptors intrinsic to the melanophores, regardless of the actual UV content. In older embryos and early larvae with functional retinal photoreceptors in contrast, this light-induced dispersion is counteracted by a delayed aggregation in the absence of UV light. These data suggest that the primary function of melanosome dispersal has evolved as a protective adaption to prevent UV damage, which was only later co-opted for camouflage. PMID:24489905

Ambient-Light-Canceling Camera Using Subtraction of Frames

NASA Technical Reports Server (NTRS)

Morookian, John Michael

2004-01-01

The ambient-light-canceling camera (ALCC) is a proposed near-infrared electronic camera that would utilize a combination of (1) synchronized illumination during alternate frame periods and (2) subtraction of readouts from consecutive frames to obtain images without a background component of ambient light. The ALCC is intended especially for use in tracking the motion of an eye by the pupil center corneal reflection (PCCR) method. Eye tracking by the PCCR method has shown potential for application in human-computer interaction for people with and without disabilities, and for noninvasive monitoring, detection, and even diagnosis of physiological and neurological deficiencies. In the PCCR method, an eye is illuminated by near-infrared light from a lightemitting diode (LED). Some of the infrared light is reflected from the surface of the cornea. Some of the infrared light enters the eye through the pupil and is reflected from back of the eye out through the pupil a phenomenon commonly observed as the red-eye effect in flash photography. An electronic camera is oriented to image the user's eye. The output of the camera is digitized and processed by algorithms that locate the two reflections. Then from the locations of the centers of the two reflections, the direction of gaze is computed. As described thus far, the PCCR method is susceptible to errors caused by reflections of ambient light. Although a near-infrared band-pass optical filter can be used to discriminate against ambient light, some sources of ambient light have enough in-band power to compete with the LED signal. The mode of operation of the ALCC would complement or supplant spectral filtering by providing more nearly complete cancellation of the effect of ambient light. In the operation of the ALCC, a near-infrared LED would be pulsed on during one camera frame period and off during the next frame period. Thus, the scene would be illuminated by both the LED (signal) light and the ambient (background) light during one frame period, and would be illuminated with only ambient (background) light during the next frame period. The camera output would be digitized and sent to a computer, wherein the pixel values of the background-only frame would be subtracted from the pixel values of the signal-plus-background frame to obtain signal-only pixel values (see figure). To prevent artifacts of motion from entering the images, it would be necessary to acquire image data at a rate greater than the standard video rate of 30 frames per second. For this purpose, the ALCC would exploit a novel control technique developed at NASA s Jet Propulsion Laboratory for advanced charge-coupled-device (CCD) cameras. This technique provides for readout from a subwindow [region of interest (ROI)] within the image frame. Because the desired reflections from the eye would typically occupy a small fraction of the area within the image frame, the ROI capability would make it possible to acquire and subtract pixel values at rates of several hundred frames per second considerably greater than the standard video rate and sufficient to both (1) suppress motion artifacts and (2) track the motion of the eye between consecutive subtractive frame pairs.

A Burst-Mode Photon-Counting Receiver with Automatic Channel Estimation and Bit Rate Detection

DTIC Science & Technology

2016-02-24

communication at data rates up to 10.416 Mb/s over a 30-foot water channel. To the best of our knowledge, this is the first demonstration of burst-mode...obstructions. The receiver is capable of on-the-fly data rate detection and adapts to changing levels of signal and background light. The receiver...receiver. We demonstrate on-the-fly rate detection, channel BER within 0.2 dB of theory across all data rates, and error-free performance within 1.82 dB

Hiding opaque eyes in transparent organisms: a potential role for larval eyeshine in stomatopod crustaceans.

PubMed

Feller, K D; Cronin, T W

2014-09-15

Opaque screening pigments are a fundamental requisite for preserving resolution in image-forming eyes. Possession of any type of image-forming eye in a transparent, pelagic animal will thus undermine the ability of that animal to be invisible in the water column. Transparent, pelagic animals must therefore deal with the trade-off between the ability to see and the ability of other animals to see them. Stomatopod larvae, like many transparent crustaceans, possess specialized optics in their compound eyes that minimize the volume of the opaque retina. Though the volumes of these retinas are reduced, their opacity remains conspicuous to an observer. The light reflected from structures overlying the retinas of stomatopod crustacean larval eyes, referred to here as eyeshine, is hypothesized to further reduce the visibility of opaque retinas. Blue or green wavelengths of light are most strongly reflected in stomatopod larval eyeshine, suggesting a putative spectral matching to the light environment against which the larval eyes are viewed. We tested the efficacy of stomatopod crustacean larval eyeshine as an ocular camouflaging mechanism by photographing larvae in their natural light environment and analysing the contrast of eyes with the background light. To test for spectral matching between stomatopod larval eyeshine and the background light environment, we characterized the spectrum of eyeshine and calculated its performance using radiometric measurements collected at the time of each photographic series. These results are the first to demonstrate an operative mirror camouflage matched in both spectrum and radiance to the pelagic background light environment. © 2014. Published by The Company of Biologists Ltd.

COBE'S INFRARED VIEW OF THE UNIVERSE

NASA Technical Reports Server (NTRS)

2002-01-01

These three pictures are maps of the full sky as seen in infrared light. The top two are composite images taken in wavelengths of 60, 100, and 240 micrometers. The 60-micrometer brightness is shown in blue, the 100- micrometer brightness in green, and the 240-micrometer brightness in red. The bottom image shows just the 240-micrometer brightness after foreground light from the solar system and Galaxy has been removed. The images were compiled from data taken between December 1989 and September 1990 by the Diffuse Infrared Background Experiment (DIRBE) on board NASA's Cosmic Background Explorer (COBE). They illustrate the steps scientists used to find the cosmic infrared background, which is a radiative fossil containing cumulative starlight which now appears in the infrared due to the cosmic redshift and by absorption and re-emission by dust in the universe since the Big Bang. The top picture represents the brightness of the full sky as seen in infrared light. The bright yellow-orange line across the center of the image arises from interstellar dust in the plane of our Milky Way Galaxy, with the center of the Galaxy at the center of the image. The red color above and below this line shows additional wispy clouds of interstellar dust. The blue S-shaped color arises from interplanetary dust in the solar system. The middle picture represents a view of the sky after the foreground glow of the solar system dust has been extracted. This image is dominated by emission from interstellar dust in the Milky Way Galaxy. The two bright objects in the center of the lower right quadrant are nearby galaxies, the Large and Small Magellanic Clouds. After the infrared light from our solar system and galaxy has been removed, what remains is a uniform cosmic infrared background. The line across the center is an artifact from removal of galactic light. The DIRBE team reports detection of this cosmic background light also at 140 micrometers, and has set limits to its brightness at eight other infrared wavelengths from 1.25 to 100 micrometers. Credits: Michael Hauser (Space Telescope Science Institute), the COBE/DIRBE Science Team, and NASA's Office of Space Science

Light propagation in Swiss-cheese models of random close-packed Szekeres structures: Effects of anisotropy and comparisons with perturbative results

NASA Astrophysics Data System (ADS)

Koksbang, S. M.

2017-03-01

Light propagation in two Swiss-cheese models based on anisotropic Szekeres structures is studied and compared with light propagation in Swiss-cheese models based on the Szekeres models' underlying Lemaitre-Tolman-Bondi models. The study shows that the anisotropy of the Szekeres models has only a small effect on quantities such as redshift-distance relations, projected shear and expansion rate along individual light rays. The average angular diameter distance to the last scattering surface is computed for each model. Contrary to earlier studies, the results obtained here are (mostly) in agreement with perturbative results. In particular, a small negative shift, δ DA≔D/A-DA ,b g DA ,b g , in the angular diameter distance is obtained upon line-of-sight averaging in three of the four models. The results are, however, not statistically significant. In the fourth model, there is a small positive shift which has an especially small statistical significance. The line-of-sight averaged inverse magnification at z =1100 is consistent with 1 to a high level of confidence for all models, indicating that the area of the surface corresponding to z =1100 is close to that of the background.

Dopamine D1 receptor activation contributes to light-adapted changes in retinal inhibition to rod bipolar cells.

PubMed

Flood, Michael Daniel; Moore-Dotson, Johnnie M; Eggers, Erika D

2018-05-30

Dopamine modulation of retinal signaling has been shown to be an important part of retinal adaptation to increased background light levels but the role of dopamine modulation of retinal inhibition is not clear. We previously showed that light adaptation causes a large reduction in inhibition to rod bipolar cells, potentially to match the decrease in excitation after rod saturation. In this study we determined how dopamine D1 receptors in the inner retina contribute to this modulation. We found that D1 receptor activation significantly decreased the magnitude of inhibitory light responses from rod bipolar cells, while D1 receptor blockade during light adaptation partially prevented this decline. To determine what mechanisms were involved in the modulation of inhibitory light responses, we measured the effect of D1 receptor activation on spontaneous currents and currents evoked from electrically stimulating amacrine cell inputs to rod bipolar cells. D1 receptor activation decreased the frequency of spontaneous inhibition with no change in event amplitudes, suggesting a presynaptic change in amacrine cell activity in agreement with previous reports that rod bipolar cells lack D1 receptors. Additionally, we found that D1 receptor activation reduced the amplitude of electrically-evoked responses, showing that D1 receptors can modulate amacrine cells directly. Our results suggest that D1 receptor activation can replicate a large portion, but not all of the effects of light adaptation, likely by modulating release from amacrine cells onto rod bipolar cells.

Effects of reduced natural background radiation on Drosophila melanogaster growth and development as revealed by the FLYINGLOW program.

PubMed

Morciano, Patrizia; Iorio, Roberto; Iovino, Daniela; Cipressa, Francesca; Esposito, Giuseppe; Porrazzo, Antonella; Satta, Luigi; Alesse, Edoardo; Tabocchini, Maria Antonella; Cenci, Giovanni

2018-01-01

Natural background radiation of Earth and cosmic rays played a relevant role during the evolution of living organisms. However, how chronic low doses of radiation can affect biological processes is still unclear. Previous data have indicated that cells grown at the Gran Sasso Underground Laboratory (LNGS, L'Aquila) of National Institute of Nuclear Physics (INFN) of Italy, where the dose rate of cosmic rays and neutrons is significantly reduced with respect to the external environment, elicited an impaired response against endogenous damage as compared to cells grown outside LNGS. This suggests that environmental radiation contributes to the development of defense mechanisms at cellular level. To further understand how environmental radiation affects metabolism of living organisms, we have recently launched the FLYINGLOW program that aims at exploiting Drosophila melanogaster as a model for evaluating the effects of low doses/dose rates of radiation at the organismal level. Here, we will present a comparative data set on lifespan, motility and fertility from different Drosophila strains grown in parallel at LNGS and in a reference laboratory at the University of L'Aquila. Our data suggest the reduced radiation environment can influence Drosophila development and, depending on the genetic background, may affect viability for several generations even when flies are moved back to normal background radiation. As flies are considered a valuable model for human biology, our results might shed some light on understanding the effect of low dose radiation also in humans. © 2017 Wiley Periodicals, Inc.

Two-Photon Infrared Resonance Can Enhance Coherent Raman Scattering

NASA Astrophysics Data System (ADS)

Traverso, Andrew J.; Hokr, Brett; Yi, Zhenhuan; Yuan, Luqi; Yamaguchi, Shoichi; Scully, Marlan O.; Yakovlev, Vladislav V.

2018-02-01

In this Letter we present a new technique for attaining efficient low-background coherent Raman scattering where the Raman coherence is mediated by a tunable infrared laser in two-photon resonance with a chosen vibrational transition. In addition to the traditional benefits of conventional coherent Raman schemes, this approach offers a number of advantages including potentially higher emission intensity, reduction of nonresonant four-wave mixing background, preferential excitation of the anti-Stokes field, and simplified phase matching conditions. In particular, this is demonstrated in gaseous methane along the ν1 (A1) and ν3 (T2) vibrational levels using an infrared field tuned between 1400 and 1600 cm-1 and a 532-nm pump field. This approach has broad applications, from coherent light generation to spectroscopic remote sensing and chemically specific imaging in microscopy.

Campanulaceae: a family with small seeds that require light for germination

PubMed Central

Koutsovoulou, Katerina; Daws, Matthew I.; Thanos, Costas A.

2014-01-01

Background and Aims The Campanulaceae is a large cosmopolitan family, but is understudied in terms of germination, and seed biology in general. Small seed mass (usually in the range 10–200 µg) is a noteworthy trait of the family, and having small seeds is commonly associated with a light requirement. Thus, the purpose of this study was to investigate the effect of light on germination in 131 taxa of the Campanulaceae family, from all five continents of its distribution. Methods For all taxa, seed germination was tested in light (8 or 12 h photoperiod) and continuous darkness under constant and alternating temperatures. For four taxa, the effect of light on germination was examined over a wide range of temperatures on a thermogradient plate, and the possible substitution of the light requirement by gibberellic acid and nitrate was examined in ten taxa. Key Results For all 131 taxa, seed germination was higher in light than in darkness for every temperature tested. Across species, the light requirement decreased significantly with increasing seed mass. For larger seeded species, germination in the dark reached higher levels under alternating than under constant temperatures. Gibberellic acid promoted germination in darkness whereas nitrates partially substituted for a light requirement only in species showing some dark germination. Conclusions A light requirement for germination, observed in virtually all taxa examined, constitutes a collective characteristic of the family. It is postulated that smaller seeded taxa might germinate only on the soil surface or at shallow depths, while larger seeded species might additionally germinate when buried in the soil if cued to do so by fluctuating temperatures. PMID:24232382

The effect of reduced street lighting on road casualties and crime in England and Wales: controlled interrupted time series analysis

PubMed Central

Steinbach, Rebecca; Perkins, Chloe; Tompson, Lisa; Johnson, Shane; Armstrong, Ben; Green, Judith; Grundy, Chris; Wilkinson, Paul

2015-01-01

Background Many local authorities in England and Wales have reduced street lighting at night to save money and reduce carbon emissions. There is no evidence to date on whether these reductions impact on public health. We quantified the effect of 4 street lighting adaptation strategies (switch off, part-night lighting, dimming and white light) on casualties and crime in England and Wales. Methods Observational study based on analysis of geographically coded police data on road traffic collisions and crime in 62 local authorities. Conditional Poisson models were used to analyse longitudinal changes in the counts of night-time collisions occurring on affected roads during 2000–2013, and crime within census Middle Super Output Areas during 2010–2013. Effect estimates were adjusted for regional temporal trends in casualties and crime. Results There was no evidence that any street lighting adaptation strategy was associated with a change in collisions at night. There was significant statistical heterogeneity in the effects on crime estimated at police force level. Overall, there was no evidence for an association between the aggregate count of crime and switch off (RR 0.11; 95% CI 0.01 to 2.75) or part-night lighting (RR 0.96; 95% CI 0.86 to 1.06). There was weak evidence for a reduction in the aggregate count of crime and dimming (RR 0.84; 95% CI 0.70 to 1.02) and white light (RR 0.89; 95% CI 0.77 to 1.03). Conclusions This study found little evidence of harmful effects of switch off, part-night lighting, dimming, or changes to white light/LEDs on road collisions or crime in England and Wales. PMID:26219885

The Imprint of the Extragalactic Background Light in the Gamma-Ray Spectra of Blazars

NASA Technical Reports Server (NTRS)

Ackermann, M.; Ajello, M.; Allafort, A.; Schady, P.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bellazzini, R; Blandford, R. D.;

[Achromatic watercolor effect: about requirement of formation of sumi painting effect].

PubMed

Takashima, Midori

2008-10-01

The watercolor effect (Pinna, Brelstaff, & Spillmann, 2001) is a new color spreading phenomenon. Pinna et al. (2001) proposed that the watercolor effect is a new Gestalt factor because it determines figure-ground organization more strongly than classical Gestalt factors. We used achroriatic watercolor patterns and varied the lightness of the background and two border lines to study the relationship between the color spreading effect and figure-ground organization. The results demonstrated (a)a bidirectional color spreading phenomenon when the background lightness was between the two border-lines' lightness, and that (b) some patterns elicit only a color spreading effect without organization of figure-ground, while others elicit only figure-ground organization without a color spreading effect.

Laser Studies of Gas Phase Radical Reactions.

DTIC Science & Technology

1989-01-01

synchronised chopper ( Rofin 7500) to block the laser beam on alternate shots to allow background subtraction. Signal due to scattered laser light was...synchronised chopper ( Rofin 7500) to block the laser beam on alternate shots to allow background subtraction. Signal due to scattered laser light was...Cassufication) (U) Laser Studies of Gas Phase Radical Reactions 𔃼 ,ERSRP4AL UTHOR($) I3a. TYPE Of REPORT 13b. TIME COVERtD 14 D T8?’F JPORT (Year, Maonlth, Da

SiPM timing characteristics under conditions of a large background for lidars

NASA Astrophysics Data System (ADS)

Antonova, A. M.; Kaplin, V. A.

2018-01-01

Silicon photomultipliers (SiPM) have found their use in various fields of industry and scientific experiments. This paper considers study of the SiPM possibility to detect low-intensity light pulses (down to single photons) under high-intensity background illumination. This may be useful for the development of laser rangefinders operating under natural light using SiPM as crucial photosensor. Moreover, the presented data describes some physical properties of LIDAR with SiPM under radiation exposure, which always affects its intrinsic noise.

DARWIN: towards the ultimate dark matter detector

NASA Astrophysics Data System (ADS)

Aalbers, J.; Agostini, F.; Alfonsi, M.; Amaro, F. D.; Amsler, C.; Aprile, E.; Arazi, L.; Arneodo, F.; Barrow, P.; Baudis, L.; Benabderrahmane, M. L.; Berger, T.; Beskers, B.; Breskin, A.; Breur, P. A.; Brown, A.; Brown, E.; Bruenner, S.; Bruno, G.; Budnik, R.; Bütikofer, L.; Calvén, J.; Cardoso, J. M. R.; Cichon, D.; Coderre, D.; Colijn, A. P.; Conrad, J.; Cussonneau, J. P.; Decowski, M. P.; Diglio, S.; Drexlin, G.; Duchovni, E.; Erdal, E.; Eurin, G.; Ferella, A.; Fieguth, A.; Fulgione, W.; Gallo Rosso, A.; Di Gangi, P.; Di Giovanni, A.; Galloway, M.; Garbini, M.; Geis, C.; Glueck, F.; Grandi, L.; Greene, Z.; Grignon, C.; Hasterok, C.; Hannen, V.; Hogenbirk, E.; Howlett, J.; Hilk, D.; Hils, C.; James, A.; Kaminsky, B.; Kazama, S.; Kilminster, B.; Kish, A.; Krauss, L. M.; Landsman, H.; Lang, R. F.; Lin, Q.; Linde, F. L.; Lindemann, S.; Lindner, M.; Lopes, J. A. M.; Marrodán Undagoitia, T.; Masbou, J.; Massoli, F. V.; Mayani, D.; Messina, M.; Micheneau, K.; Molinario, A.; Morå, K. D.; Morteau, E.; Murra, M.; Naganoma, J.; Newstead, J. L.; Ni, K.; Oberlack, U.; Pakarha, P.; Pelssers, B.; de Perio, P.; Persiani, R.; Piastra, F.; Piro, M. C.; Plante, G.; Rauch, L.; Reichard, S.; Rizzo, A.; Rupp, N.; Dos Santos, J. M. F.; Sartorelli, G.; Scheibelhut, M.; Schindler, S.; Schumann, M.; Schreiner, J.; Scotto Lavina, L.; Selvi, M.; Shagin, P.; Silva, M. C.; Simgen, H.; Sissol, P.; von Sivers, M.; Thers, D.; Thurn, J.; Tiseni, A.; Trotta, R.; Tunnell, C. D.; Valerius, K.; Vargas, M. A.; Wang, H.; Wei, Y.; Weinheimer, C.; Wester, T.; Wulf, J.; Zhang, Y.; Zhu, T.; Zuber, K.

2016-11-01

DARk matter WImp search with liquid xenoN (DARWIN) will be an experiment for the direct detection of dark matter using a multi-ton liquid xenon time projection chamber at its core. Its primary goal will be to explore the experimentally accessible parameter space for Weakly Interacting Massive Particles (WIMPs) in a wide mass-range, until neutrino interactions with the target become an irreducible background. The prompt scintillation light and the charge signals induced by particle interactions in the xenon will be observed by VUV sensitive, ultra-low background photosensors. Besides its excellent sensitivity to WIMPs above a mass of 5 GeV/c2, such a detector with its large mass, low-energy threshold and ultra-low background level will also be sensitive to other rare interactions. It will search for solar axions, galactic axion-like particles and the neutrinoless double-beta decay of 136Xe, as well as measure the low-energy solar neutrino flux with < 1% precision, observe coherent neutrino-nucleus interactions, and detect galactic supernovae. We present the concept of the DARWIN detector and discuss its physics reach, the main sources of backgrounds and the ongoing detector design and R&D efforts.

DARWIN: towards the ultimate dark matter detector

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

Aalbers, J.; Breur, P.A.; Brown, A.

2016-11-01

DARk matter WImp search with liquid xenoN (DARWIN) will be an experiment for the direct detection of dark matter using a multi-ton liquid xenon time projection chamber at its core. Its primary goal will be to explore the experimentally accessible parameter space for Weakly Interacting Massive Particles (WIMPs) in a wide mass-range, until neutrino interactions with the target become an irreducible background. The prompt scintillation light and the charge signals induced by particle interactions in the xenon will be observed by VUV sensitive, ultra-low background photosensors. Besides its excellent sensitivity to WIMPs above a mass of 5 GeV/ c {supmore » 2}, such a detector with its large mass, low-energy threshold and ultra-low background level will also be sensitive to other rare interactions. It will search for solar axions, galactic axion-like particles and the neutrinoless double-beta decay of {sup 136}Xe, as well as measure the low-energy solar neutrino flux with < 1% precision, observe coherent neutrino-nucleus interactions, and detect galactic supernovae. We present the concept of the DARWIN detector and discuss its physics reach, the main sources of backgrounds and the ongoing detector design and R and D efforts.« less

The production of a key floral volatile is dependent on UV light in a sexually deceptive orchid

PubMed Central

Falara, Vasiliki; Amarasinghe, Ranamalie; Poldy, Jacqueline; Pichersky, Eran; Barrow, Russell A.; Peakall, Rod

2013-01-01

Background and Aims Plants use a diverse range of visual and olfactory cues to advertize to pollinators. Australian Chiloglottis orchids employ one to three related chemical variants, all 2,5-dialkylcyclohexane-1,3-diones or ‘chiloglottones’ to sexually attract their specific male pollinators. Here an investigation was made of the physiological aspects of chiloglottone synthesis and storage that have not previously been examined. Methods The location of chiloglottone production was determined and developmental and diurnal changes by GC-MS analysis of floral tissue extracts was monitored in two distantly related Chiloglottis species. Light treatment experiments were also performed using depleted flowers to evaluate if sunlight is required for chiloglottone production; which specific wavelengths of light are required was also determined. Key Results Chiloglottone production only occurs in specific floral tissues (the labellum calli and sepals) of open flowers. Upon flower opening chiloglottone production is rapid and levels remain more or less stable both day and night, and over the 2- to 3-week lifetime of the flower. Furthermore, it was determined that chiloglottone production requires continuous sunlight, and determined the optimal wavelengths of sunlight in the UV-B range (with peak of 300 nm). Conclusions UV-B light is required for the synthesis of chiloglottones – the semiochemicals used by Chiloglottis orchids to sexually lure their male pollinators. This discovery appears to be the first case to our knowledge where plant floral odour production depends on UV-B radiation at normal levels of sunlight. In the future, identification of the genes and enzymes involved, will allow us to understand better the role of UV-B light in the biosynthesis of chiloglottones. PMID:23091095

Evidence for light-by-light scattering in heavy-ion collisions with the ATLAS detector at the LHC

NASA Astrophysics Data System (ADS)

Aaboud, M.; Aad, G.; Abbott, B.; Abdallah, J.; Abdinov, O.; Abeloos, B.; Abidi, S. H.; Abouzeid, O. S.; Abraham, N. L.; Abramowicz, H.; Abreu, H.; Abreu, R.; Abulaiti, Y.; Acharya, B. S.; Adachi, S.; Adamczyk, L.; Adelman, J.; Adersberger, M.; Adye, T.; Affolder, A. A.; Agatonovic-Jovin, T.; Agheorghiesei, C.; Aguilar-Saavedra, J. A.; Ahlen, S. P.; Ahmadov, F.; Aielli, G.; Akatsuka, S.; Akerstedt, H.; Åkesson, T. P. A.; Akimov, A. V.; Alberghi, G. L.; Albert, J.; Alconada Verzini, M. J.; Aleksa, M.; Aleksandrov, I. N.; Alexa, C.; Alexander, G.; Alexopoulos, T.; Alhroob, M.; Ali, B.; Aliev, M.; Alimonti, G.; Alison, J.; Alkire, S. P.; Allbrooke, B. M. M.; Allen, B. W.; Allport, P. P.; Aloisio, A.; Alonso, A.; Alonso, F.; Alpigiani, C.; Alshehri, A. A.; Alstaty, M.; Alvarez Gonzalez, B.; Álvarez Piqueras, D.; Alviggi, M. G.; Amadio, B. T.; Amaral Coutinho, Y.; Amelung, C.; Amidei, D.; Amor Dos Santos, S. P.; Amorim, A.; Amoroso, S.; Amundsen, G.; Anastopoulos, C.; Ancu, L. S.; Andari, N.; Andeen, T.; Anders, C. F.; Anders, J. K.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Angelidakis, S.; Angelozzi, I.; Angerami, A.; Anghinolfi, F.; Anisenkov, A. V.; Anjos, N.; Annovi, A.; Antel, C.; Antonelli, M.; Antonov, A.; Antrim, D. J.; Anulli, F.; Aoki, M.; Aperio Bella, L.; Arabidze, G.; Arai, Y.; Araque, J. P.; Araujo Ferraz, V.; Arce, A. T. H.; Ardell, R. E.; Arduh, F. A.; Arguin, J.-F.; Argyropoulos, S.; Arik, M.; Armbruster, A. J.; Armitage, L. J.; Arnaez, O.; Arnold, H.; Arratia, M.; Arslan, O.; Artamonov, A.; Artoni, G.; Artz, S.; Asai, S.; Asbah, N.; Ashkenazi, A.; Asquith, L.; Assamagan, K.; Astalos, R.; Atkinson, M.; Atlay, N. B.; Augsten, K.; Avolio, G.; Axen, B.; Ayoub, M. K.; Azuelos, G.; Baas, A. E.; Baca, M. J.; Bachacou, H.; Bachas, K.; Backes, M.; Backhaus, M.; Bagiacchi, P.; Bagnaia, P.; Baines, J. T.; Bajic, M.; Baker, O. K.; Baldin, E. M.; Balek, P.; Balestri, T.; Balli, F.; Balunas, W. K.; Banas, E.; Banerjee, Sw.; Bannoura, A. A. E.; Barak, L.; Barberio, E. L.; Barberis, D.; Barbero, M.; Barillari, T.; Barisits, M.-S.; Barklow, T.; Barlow, N.; Barnes, S. L.; Barnett, B. M.; Barnett, R. M.; Barnovska-Blenessy, Z.; Baroncelli, A.; Barone, G.; Barr, A. J.; Barranco Navarro, L.; Barreiro, F.; Barreiro Guimarães da Costa, J.; Bartoldus, R.; Barton, A. E.; Bartos, P.; Basalaev, A.; Bassalat, A.; Bates, R. L.; Batista, S. J.; Batley, J. R.; Battaglia, M.; Bauce, M.; Bauer, F.; Bawa, H. S.; Beacham, J. B.; Beattie, M. D.; Beau, T.; Beauchemin, P. H.; Bechtle, P.; Beck, H. P.; Becker, K.; Becker, M.; Beckingham, M.; Becot, C.; Beddall, A. J.; Beddall, A.; Bednyakov, V. A.; Bedognetti, M.; Bee, C. P.; Beermann, T. A.; Begalli, M.; Begel, M.; Behr, J. K.; Bell, A. S.; Bella, G.; Bellagamba, L.; Bellerive, A.; Bellomo, M.; Belotskiy, K.; Beltramello, O.; Belyaev, N. L.; Benary, O.; Benchekroun, D.; Bender, M.; Bendtz, K.; Benekos, N.; Benhammou, Y.; Benhar Noccioli, E.; Benitez, J.; Benjamin, D. P.; Benoit, M.; Bensinger, J. R.; Bentvelsen, S.; Beresford, L.; Beretta, M.; Berge, D.; Bergeaas Kuutmann, E.; Berger, N.; Beringer, J.; Berlendis, S.; Bernard, N. R.; Bernardi, G.; Bernius, C.; Bernlochner, F. U.; Berry, T.; Berta, P.; Bertella, C.; Bertoli, G.; Bertolucci, F.; Bertram, I. A.; Bertsche, C.; Bertsche, D.; Besjes, G. J.; Bessidskaia Bylund, O.; Bessner, M.; Besson, N.; Betancourt, C.; Bethani, A.; Bethke, S.; Bevan, A. J.; Bianchi, R. M.; Bianco, M.; Biebel, O.; Biedermann, D.; Bielski, R.; Biesuz, N. V.; Biglietti, M.; Bilbao de Mendizabal, J.; Billoud, T. R. V.; Bilokon, H.; Bindi, M.; Bingul, A.; Bini, C.; Biondi, S.; Bisanz, T.; Bittrich, C.; Bjergaard, D. M.; Black, C. W.; Black, J. E.; Black, K. M.; Blackburn, D.; Blair, R. E.; Blazek, T.; Bloch, I.; Blocker, C.; Blue, A.; Blum, W.; Blumenschein, U.; Blunier, S.; Bobbink, G. J.; Bobrovnikov, V. S.; Bocchetta, S. S.; Bocci, A.; Bock, C.; Boehler, M.; Boerner, D.; Bogavac, D.; Bogdanchikov, A. G.; Bohm, C.; Boisvert, V.; Bokan, P.; Bold, T.; Boldyrev, A. S.; Bomben, M.; Bona, M.; Boonekamp, M.; Borisov, A.; Borissov, G.; Bortfeldt, J.; Bortoletto, D.; Bortolotto, V.; Bos, K.; Boscherini, D.; Bosman, M.; Bossio Sola, J. D.; Boudreau, J.; Bouffard, J.; Bouhova-Thacker, E. V.; Boumediene, D.; Bourdarios, C.; Boutle, S. K.; Boveia, A.; Boyd, J.; Boyko, I. R.; Bracinik, J.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J. E.; Breaden Madden, W. D.; Brendlinger, K.; Brennan, A. J.; Brenner, L.; Brenner, R.; Bressler, S.; Briglin, D. L.; Bristow, T. M.; Britton, D.; Britzger, D.; Brochu, F. M.; Brock, I.; Brock, R.; Brooijmans, G.; Brooks, T.; Brooks, W. K.; Brosamer, J.; Brost, E.; Broughton, J. H.; Bruckman de Renstrom, P. A.; Bruncko, D.; Bruni, A.; Bruni, G.; Bruni, L. S.; Brunt, B. H.; Bruschi, M.; Bruscino, N.; Bryant, P.; Bryngemark, L.; Buanes, T.; Buat, Q.; Buchholz, P.; Buckley, A. G.; Budagov, I. A.; Buehrer, F.; Bugge, M. K.; Bulekov, O.; Bullock, D.; Burckhart, H.; Burdin, S.; Burgard, C. D.; Burger, A. M.; Burghgrave, B.; Burka, K.; Burke, S.; Burmeister, I.; Burr, J. T. P.; Busato, E.; Büscher, D.; Büscher, V.; Bussey, P.; Butler, J. M.; Buttar, C. M.; Butterworth, J. M.; Butti, P.; Buttinger, W.; Buzatu, A.; Buzykaev, A. R.; Cabrera Urbán, S.; Caforio, D.; Cairo, V. M.; Cakir, O.; Calace, N.; Calafiura, P.; Calandri, A.; Calderini, G.; Calfayan, P.; Callea, G.; Caloba, L. P.; Calvente Lopez, S.; Calvet, D.; Calvet, S.; Calvet, T. P.; Camacho Toro, R.; Camarda, S.; Camarri, P.; Cameron, D.; Caminal Armadans, R.; Camincher, C.; Campana, S.; Campanelli, M.; Camplani, A.; Campoverde, A.; Canale, V.; Cano Bret, M.; Cantero, J.; Cao, T.; Capeans Garrido, M. D. M.; Caprini, I.; Caprini, M.; Capua, M.; Carbone, R. M.; Cardarelli, R.; Cardillo, F.; Carli, I.; Carli, T.; Carlino, G.; Carlson, B. T.; Carminati, L.; Carney, R. M. D.; Caron, S.; Carquin, E.; Carrillo-Montoya, G. D.; Carvalho, J.; Casadei, D.; Casado, M. P.; Casolino, M.; Casper, D. W.; Castelijn, R.; Castelli, A.; Castillo Gimenez, V.; Castro, N. F.; Catinaccio, A.; Catmore, J. R.; Cattai, A.; Caudron, J.; Cavaliere, V.; Cavallaro, E.; Cavalli, D.; Cavalli-Sforza, M.; Cavasinni, V.; Celebi, E.; Ceradini, F.; Cerda Alberich, L.; Cerqueira, A. S.; Cerri, A.; Cerrito, L.; Cerutti, F.; Cervelli, A.; Cetin, S. A.; Chafaq, A.; Chakraborty, D.; Chan, S. K.; Chan, W. S.; Chan, Y. L.; Chang, P.; Chapman, J. D.; Charlton, D. G.; Chatterjee, A.; Chau, C. C.; Chavez Barajas, C. A.; Che, S.; Cheatham, S.; Chegwidden, A.; Chekanov, S.; Chekulaev, S. V.; Chelkov, G. A.; Chelstowska, M. A.; Chen, C.; Chen, H.; Chen, S.; Chen, S.; Chen, X.; Chen, Y.; Cheng, H. C.; Cheng, H. J.; Cheng, Y.; Cheplakov, A.; Cheremushkina, E.; Cherkaoui El Moursli, R.; Chernyatin, V.; Cheu, E.; Chevalier, L.; Chiarella, V.; Chiarelli, G.; Chiodini, G.; Chisholm, A. S.; Chitan, A.; Chiu, Y. H.; Chizhov, M. V.; Choi, K.; Chomont, A. R.; Chouridou, S.; Chow, B. K. B.; Christodoulou, V.; Chromek-Burckhart, D.; Chu, M. C.; Chudoba, J.; Chuinard, A. J.; Chwastowski, J. J.; Chytka, L.; Ciftci, A. K.; Cinca, D.; Cindro, V.; Cioara, I. A.; Ciocca, C.; Ciocio, A.; Cirotto, F.; Citron, Z. H.; Citterio, M.; Ciubancan, M.; Clark, A.; Clark, B. L.; Clark, M. R.; Clark, P. J.; Clarke, R. N.; Clement, C.; Coadou, Y.; Cobal, M.; Coccaro, A.; Cochran, J.; Colasurdo, L.; Cole, B.; Colijn, A. P.; Collot, J.; Colombo, T.; Conde Muiño, P.; Coniavitis, E.; Connell, S. H.; Connelly, I. A.; Consorti, V.; Constantinescu, S.; Conti, G.; Conventi, F.; Cooke, M.; Cooper, B. D.; Cooper-Sarkar, A. M.; Cormier, F.; Cormier, K. J. R.; Cornelissen, T.; Corradi, M.; Corriveau, F.; Cortes-Gonzalez, A.; Cortiana, G.; Costa, G.; Costa, M. J.; Costanzo, D.; Cottin, G.; Cowan, G.; Cox, B. E.; Cranmer, K.; Crawley, S. J.; Creager, R. A.; Cree, G.; Crépé-Renaudin, S.; Crescioli, F.; Cribbs, W. A.; Crispin Ortuzar, M.; Cristinziani, M.; Croft, V.; Crosetti, G.; Cueto, A.; Cuhadar Donszelmann, T.; Cummings, J.; Curatolo, M.; Cúth, J.; Czirr, H.; Czodrowski, P.; D'Amen, G.; D'Auria, S.; D'Onofrio, M.; da Cunha Sargedas de Sousa, M. J.; da Via, C.; Dabrowski, W.; Dado, T.; Dai, T.; Dale, O.; Dallaire, F.; Dallapiccola, C.; Dam, M.; Dandoy, J. R.; Dang, N. P.; Daniells, A. C.; Dann, N. S.; Danninger, M.; Dano Hoffmann, M.; Dao, V.; Darbo, G.; Darmora, S.; Dassoulas, J.; Dattagupta, A.; Daubney, T.; Davey, W.; David, C.; Davidek, T.; Davies, M.; Davison, P.; Dawe, E.; Dawson, I.; de, K.; de Asmundis, R.; de Benedetti, A.; de Castro, S.; de Cecco, S.; de Groot, N.; de Jong, P.; de la Torre, H.; de Lorenzi, F.; de Maria, A.; de Pedis, D.; de Salvo, A.; de Sanctis, U.; de Santo, A.; de Vasconcelos Corga, K.; de Vivie de Regie, J. B.; Dearnaley, W. J.; Debbe, R.; Debenedetti, C.; Dedovich, D. V.; Dehghanian, N.; Deigaard, I.; Del Gaudio, M.; Del Peso, J.; Del Prete, T.; Delgove, D.; Deliot, F.; Delitzsch, C. M.; Dell'Acqua, A.; Dell'Asta, L.; Dell'Orso, M.; Della Pietra, M.; Della Volpe, D.; Delmastro, M.; Delporte, C.; Delsart, P. A.; Demarco, D. A.; Demers, S.; Demichev, M.; Demilly, A.; Denisov, S. P.; Denysiuk, D.; Derendarz, D.; Derkaoui, J. E.; Derue, F.; Dervan, P.; Desch, K.; Deterre, C.; Dette, K.; Deviveiros, P. O.; Dewhurst, A.; Dhaliwal, S.; di Ciaccio, A.; di Ciaccio, L.; di Clemente, W. K.; di Donato, C.; di Girolamo, A.; di Girolamo, B.; di Micco, B.; di Nardo, R.; di Petrillo, K. F.; di Simone, A.; di Sipio, R.; di Valentino, D.; Diaconu, C.; Diamond, M.; Dias, F. A.; Diaz, M. A.; Diehl, E. B.; Dietrich, J.; Díez Cornell, S.; Dimitrievska, A.; Dingfelder, J.; Dita, P.; Dita, S.; Dittus, F.; Djama, F.; Djobava, T.; Djuvsland, J. I.; Do Vale, M. A. B.; Dobos, D.; Dobre, M.; Doglioni, C.; Dolejsi, J.; Dolezal, Z.; Donadelli, M.; Donati, S.; Dondero, P.; Donini, J.; Dopke, J.; Doria, A.; Dova, M. T.; Doyle, A. T.; Drechsler, E.; Dris, M.; Du, Y.; Duarte-Campderros, J.; Duchovni, E.; Duckeck, G.; Ducourthial, A.; Ducu, O. A.; Duda, D.; Dudarev, A.; Dudder, A. Chr.; Duffield, E. M.; Duflot, L.; Dührssen, M.; Dumancic, M.; Dumitriu, A. E.; Duncan, A. K.; Dunford, M.; Duran Yildiz, H.; Düren, M.; Durglishvili, A.; Duschinger, D.; Dutta, B.; Dyndal, M.; Eckardt, C.; Ecker, K. M.; Edgar, R. C.; Eifert, T.; Eigen, G.; Einsweiler, K.; Ekelof, T.; El Kacimi, M.; El Kosseifi, R.; Ellajosyula, V.; Ellert, M.; Elles, S.; Ellinghaus, F.; Elliot, A. A.; Ellis, N.; Elmsheuser, J.; Elsing, M.; Emeliyanov, D.; Enari, Y.; Endner, O. C.; Ennis, J. S.; Erdmann, J.; Ereditato, A.; Ernis, G.; Ernst, M.; Errede, S.; Ertel, E.; Escalier, M.; Esch, H.; Escobar, C.; Esposito, B.; Etienvre, A. I.; Etzion, E.; Evans, H.; Ezhilov, A.; Fabbri, F.; Fabbri, L.; Facini, G.; Fakhrutdinov, R. M.; Falciano, S.; Falla, R. J.; Faltova, J.; Fang, Y.; Fanti, M.; Farbin, A.; Farilla, A.; Farina, C.; Farina, E. M.; Farooque, T.; Farrell, S.; Farrington, S. M.; Farthouat, P.; Fassi, F.; Fassnacht, P.; Fassouliotis, D.; Faucci Giannelli, M.; Favareto, A.; Fawcett, W. J.; Fayard, L.; Fedin, O. L.; Fedorko, W.; Feigl, S.; Feligioni, L.; Feng, C.; Feng, E. J.; Feng, H.; Fenyuk, A. B.; Feremenga, L.; Fernandez Martinez, P.; Fernandez Perez, S.; Ferrando, J.; Ferrari, A.; Ferrari, P.; Ferrari, R.; Ferreira de Lima, D. E.; Ferrer, A.; Ferrere, D.; Ferretti, C.; Fiedler, F.; Filipčič, A.; Filipuzzi, M.; Filthaut, F.; Fincke-Keeler, M.; Finelli, K. D.; Fiolhais, M. C. N.; Fiorini, L.; Fischer, A.; Fischer, C.; Fischer, J.; Fisher, W. C.; Flaschel, N.; Fleck, I.; Fleischmann, P.; Fletcher, R. R. M.; Flick, T.; Flierl, B. M.; Flores Castillo, L. R.; Flowerdew, M. J.; Forcolin, G. T.; Formica, A.; Forti, A.; Foster, A. G.; Fournier, D.; Fox, H.; Fracchia, S.; Francavilla, P.; Franchini, M.; Franchino, S.; Francis, D.; Franconi, L.; Franklin, M.; Frate, M.; Fraternali, M.; Freeborn, D.; Fressard-Batraneanu, S. M.; Freund, B.; Froidevaux, D.; Frost, J. A.; Fukunaga, C.; Fullana Torregrosa, E.; Fusayasu, T.; Fuster, J.; Gabaldon, C.; Gabizon, O.; Gabrielli, A.; Gabrielli, A.; Gach, G. P.; Gadatsch, S.; Gadomski, S.; Gagliardi, G.; Gagnon, L. G.; Gagnon, P.; Galea, C.; Galhardo, B.; Gallas, E. J.; Gallop, B. J.; Gallus, P.; Galster, G.; Gan, K. K.; Ganguly, S.; Gao, J.; Gao, Y.; Gao, Y. S.; Garay Walls, F. M.; García, C.; García Navarro, J. E.; Garcia-Sciveres, M.; Gardner, R. W.; Garelli, N.; Garonne, V.; Gascon Bravo, A.; Gasnikova, K.; Gatti, C.; Gaudiello, A.; Gaudio, G.; Gavrilenko, I. L.; Gay, C.; Gaycken, G.; Gazis, E. N.; Gee, C. N. P.; Geisen, M.; Geisler, M. P.; Gellerstedt, K.; Gemme, C.; Genest, M. H.; Geng, C.; Gentile, S.; Gentsos, C.; George, S.; Gerbaudo, D.; Gershon, A.; Ghasemi, S.; Ghneimat, M.; Giacobbe, B.; Giagu, S.; Giannetti, P.; Gibson, S. M.; Gignac, M.; Gilchriese, M.; Gillberg, D.; Gilles, G.; Gingrich, D. M.; Giokaris, N.; Giordani, M. P.; Giorgi, F. M.; Giraud, P. F.; Giromini, P.; Giugni, D.; Giuli, F.; Giuliani, C.; Giulini, M.; Gjelsten, B. K.; Gkaitatzis, S.; Gkialas, I.; Gkougkousis, E. L.; Gladilin, L. K.; Glasman, C.; Glatzer, J.; Glaysher, P. C. F.; Glazov, A.; Goblirsch-Kolb, M.; Godlewski, J.; Goldfarb, S.; Golling, T.; Golubkov, D.; Gomes, A.; Gonçalo, R.; Goncalves Gama, R.; Goncalves Pinto Firmino da Costa, J.; Gonella, G.; Gonella, L.; Gongadze, A.; González de La Hoz, S.; Gonzalez-Sevilla, S.; Goossens, L.; Gorbounov, P. A.; Gordon, H. A.; Gorelov, I.; Gorini, B.; Gorini, E.; Gorišek, A.; Goshaw, A. T.; Gössling, C.; Gostkin, M. I.; Goudet, C. R.; Goujdami, D.; Goussiou, A. G.; Govender, N.; Gozani, E.; Graber, L.; Grabowska-Bold, I.; Gradin, P. O. J.; Gramling, J.; Gramstad, E.; Grancagnolo, S.; Gratchev, V.; Gravila, P. M.; Gray, H. M.; Greenwood, Z. D.; Grefe, C.; Gregersen, K.; Gregor, I. M.; Grenier, P.; Grevtsov, K.; Griffiths, J.; Grillo, A. A.; Grimm, K.; Grinstein, S.; Gris, Ph.; Grivaz, J.-F.; Groh, S.; Gross, E.; Grosse-Knetter, J.; Grossi, G. C.; Grout, Z. J.; Guan, L.; Guan, W.; Guenther, J.; Guescini, F.; Guest, D.; Gueta, O.; Gui, B.; Guido, E.; Guillemin, T.; Guindon, S.; Gul, U.; Gumpert, C.; Guo, J.; Guo, W.; Guo, Y.; Gupta, R.; Gupta, S.; Gustavino, G.; Gutierrez, P.; Gutierrez Ortiz, N. G.; Gutschow, C.; Guyot, C.; Guzik, M. P.; Gwenlan, C.; Gwilliam, C. B.; Haas, A.; Haber, C.; Hadavand, H. K.; Hadef, A.; Hageböck, S.; Hagihara, M.; Hakobyan, H.; Haleem, M.; Haley, J.; Halladjian, G.; Hallewell, G. D.; Hamacher, K.; Hamal, P.; Hamano, K.; Hamilton, A.; Hamity, G. N.; Hamnett, P. G.; Han, L.; Han, S.; Hanagaki, K.; Hanawa, K.; Hance, M.; Haney, B.; Hanke, P.; Hansen, J. B.; Hansen, J. D.; Hansen, M. 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A.; Poppleton, A.; Pospisil, S.; Potamianos, K.; Potrap, I. N.; Potter, C. J.; Potter, C. T.; Poulard, G.; Poveda, J.; Pozo Astigarraga, M. E.; Pralavorio, P.; Pranko, A.; Prell, S.; Price, D.; Price, L. E.; Primavera, M.; Prince, S.; Proklova, N.; Prokofiev, K.; Prokoshin, F.; Protopopescu, S.; Proudfoot, J.; Przybycien, M.; Puddu, D.; Puri, A.; Puzo, P.; Qian, J.; Qin, G.; Qin, Y.; Quadt, A.; Quayle, W. B.; Queitsch-Maitland, M.; Quilty, D.; Raddum, S.; Radeka, V.; Radescu, V.; Radhakrishnan, S. K.; Radloff, P.; Rados, P.; Ragusa, F.; Rahal, G.; Raine, J. A.; Rajagopalan, S.; Rangel-Smith, C.; Ratti, M. G.; Rauch, D. M.; Rauscher, F.; Rave, S.; Ravenscroft, T.; Ravinovich, I.; Rawling, J. H.; Raymond, M.; Read, A. L.; Readioff, N. P.; Reale, M.; Rebuzzi, D. M.; Redelbach, A.; Redlinger, G.; Reece, R.; Reed, R. G.; Reeves, K.; Rehnisch, L.; Reichert, J.; Reiss, A.; Rembser, C.; Ren, H.; Rescigno, M.; Resconi, S.; Resseguie, E. D.; Rettie, S.; Reynolds, E.; Rezanova, O. L.; Reznicek, P.; Rezvani, R.; Richter, R.; Richter, S.; Richter-Was, E.; Ricken, O.; Ridel, M.; Rieck, P.; Riegel, C. J.; Rieger, J.; Rifki, O.; Rijssenbeek, M.; Rimoldi, A.; Rimoldi, M.; Rinaldi, L.; Ristić, B.; Ritsch, E.; Riu, I.; Rizatdinova, F.; Rizvi, E.; Rizzi, C.; Roberts, R. T.; Robertson, S. H.; Robichaud-Veronneau, A.; Robinson, D.; Robinson, J. E. M.; Robson, A.; Roda, C.; Rodina, Y.; Rodriguez Perez, A.; Rodriguez Rodriguez, D.; Roe, S.; Rogan, C. S.; Røhne, O.; Roloff, J.; Romaniouk, A.; Romano, M.; Romano Saez, S. M.; Romero Adam, E.; Rompotis, N.; Ronzani, M.; Roos, L.; Rosati, S.; Rosbach, K.; Rose, P.; Rosien, N.-A.; Rossetti, V.; Rossi, E.; Rossi, L. P.; Rosten, J. H. N.; Rosten, R.; Rotaru, M.; Roth, I.; Rothberg, J.; Rousseau, D.; Rozanov, A.; Rozen, Y.; Ruan, X.; Rubbo, F.; Rühr, F.; Ruiz-Martinez, A.; Rurikova, Z.; Rusakovich, N. A.; Ruschke, A.; Russell, H. L.; Rutherfoord, J. P.; Ruthmann, N.; Ryabov, Y. F.; Rybar, M.; Rybkin, G.; Ryu, S.; Ryzhov, A.; Rzehorz, G. F.; Saavedra, A. F.; Sabato, G.; Sacerdoti, S.; Sadrozinski, H. F.-W.; Sadykov, R.; Safai Tehrani, F.; Saha, P.; Sahinsoy, M.; Saimpert, M.; Saito, M.; Saito, T.; Sakamoto, H.; Sakurai, Y.; Salamanna, G.; Salazar Loyola, J. E.; Salek, D.; Sales de Bruin, P. H.; Salihagic, D.; Salnikov, A.; Salt, J.; Salvatore, D.; Salvatore, F.; Salvucci, A.; Salzburger, A.; Sammel, D.; Sampsonidis, D.; Sánchez, J.; Sanchez Martinez, V.; Sanchez Pineda, A.; Sandaker, H.; Sandbach, R. L.; Sander, C. O.; Sandhoff, M.; Sandoval, C.; Sankey, D. P. C.; Sannino, M.; Sansoni, A.; Santoni, C.; Santonico, R.; Santos, H.; Santoyo Castillo, I.; Sapp, K.; Sapronov, A.; Saraiva, J. G.; Sarrazin, B.; Sasaki, O.; Sato, K.; Sauvan, E.; Savage, G.; Savard, P.; Savic, N.; Sawyer, C.; Sawyer, L.; Saxon, J.; Sbarra, C.; Sbrizzi, A.; Scanlon, T.; Scannicchio, D. A.; Scarcella, M.; Scarfone, V.; Schaarschmidt, J.; Schacht, P.; Schachtner, B. M.; Schaefer, D.; Schaefer, L.; Schaefer, R.; Schaeffer, J.; Schaepe, S.; Schaetzel, S.; Schäfer, U.; Schaffer, A. C.; Schaile, D.; Schamberger, R. D.; Scharf, V.; Schegelsky, V. A.; Scheirich, D.; Schernau, M.; Schiavi, C.; Schier, S.; Schildgen, L. K.; Schillo, C.; Schioppa, M.; Schlenker, S.; Schmidt-Sommerfeld, K. R.; Schmieden, K.; Schmitt, C.; Schmitt, S.; Schmitz, S.; Schnoor, U.; Schoeffel, L.; Schoening, A.; Schoenrock, B. D.; Schopf, E.; Schott, M.; Schouwenberg, J. F. P.; Schovancova, J.; Schramm, S.; Schuh, N.; Schulte, A.; Schultens, M. J.; Schultz-Coulon, H.-C.; Schulz, H.; Schumacher, M.; Schumm, B. A.; Schune, Ph.; Schwartzman, A.; Schwarz, T. A.; Schweiger, H.; Schwemling, Ph.; Schwienhorst, R.; Schwindling, J.; Schwindt, T.; Sciandra, A.; Sciolla, G.; Scuri, F.; Scutti, F.; Searcy, J.; Seema, P.; Seidel, S. C.; Seiden, A.; Seixas, J. M.; Sekhniaidze, G.; Sekhon, K.; Sekula, S. J.; Semprini-Cesari, N.; Serfon, C.; Serin, L.; Serkin, L.; Sessa, M.; Seuster, R.; Severini, H.; Sfiligoj, T.; Sforza, F.; Sfyrla, A.; Shabalina, E.; Shaikh, N. W.; Shan, L. Y.; Shang, R.; Shank, J. T.; Shapiro, M.; Shatalov, P. B.; Shaw, K.; Shaw, S. M.; Shcherbakova, A.; Shehu, C. Y.; Shen, Y.; Sherwood, P.; Shi, L.; Shimizu, S.; Shimmin, C. O.; Shimojima, M.; Shirabe, S.; Shiyakova, M.; Shlomi, J.; Shmeleva, A.; Shoaleh Saadi, D.; Shochet, M. J.; Shojaii, S.; Shope, D. R.; Shrestha, S.; Shulga, E.; Shupe, M. A.; Sicho, P.; Sickles, A. M.; Sidebo, P. E.; Sideras Haddad, E.; Sidiropoulou, O.; Sidorov, D.; Sidoti, A.; Siegert, F.; Sijacki, Dj.; Silva, J.; Silverstein, S. B.; Simak, V.; Simic, Lj.; Simion, S.; Simioni, E.; Simmons, B.; Simon, M.; Sinervo, P.; Sinev, N. B.; Sioli, M.; Siragusa, G.; Siral, I.; Sivoklokov, S. Yu.; Sjölin, J.; Skinner, M. B.; Skubic, P.; Slater, M.; Slavicek, T.; Slawinska, M.; Sliwa, K.; Slovak, R.; Smakhtin, V.; Smart, B. H.; Smiesko, J.; Smirnov, N.; Smirnov, S. Yu.; Smirnov, Y.; Smirnova, L. N.; Smirnova, O.; Smith, J. W.; Smith, M. N. K.; Smith, R. W.; Smizanska, M.; Smolek, K.; Snesarev, A. A.; Snyder, I. M.; Snyder, S.; Sobie, R.; Socher, F.; Soffer, A.; Soh, D. A.; Sokhrannyi, G.; Solans Sanchez, C. A.; Solar, M.; Soldatov, E. Yu.; Soldevila, U.; Solodkov, A. A.; Soloshenko, A.; Solovyanov, O. V.; Solovyev, V.; Sommer, P.; Son, H.; Song, H. Y.; Sopczak, A.; Sorin, V.; Sosa, D.; Sotiropoulou, C. L.; Soualah, R.; Soukharev, A. M.; South, D.; Sowden, B. C.; Spagnolo, S.; Spalla, M.; Spangenberg, M.; Spanò, F.; Sperlich, D.; Spettel, F.; Spieker, T. M.; Spighi, R.; Spigo, G.; Spiller, L. A.; Spousta, M.; St. Denis, R. D.; Stabile, A.; Stamen, R.; Stamm, S.; Stanecka, E.; Stanek, R. W.; Stanescu, C.; Stanitzki, M. M.; Stapnes, S.; Starchenko, E. A.; Stark, G. H.; Stark, J.; Stark, S. H.; Staroba, P.; Starovoitov, P.; Stärz, S.; Staszewski, R.; Steinberg, P.; Stelzer, B.; Stelzer, H. J.; Stelzer-Chilton, O.; Stenzel, H.; Stewart, G. A.; Stillings, J. A.; Stockton, M. C.; Stoebe, M.; Stoicea, G.; Stolte, P.; Stonjek, S.; Stradling, A. R.; Straessner, A.; Stramaglia, M. E.; Strandberg, J.; Strandberg, S.; Strandlie, A.; Strauss, M.; Strizenec, P.; Ströhmer, R.; Strom, D. M.; Stroynowski, R.; Strubig, A.; Stucci, S. A.; Stugu, B.; Styles, N. A.; Su, D.; Su, J.; Suchek, S.; Sugaya, Y.; Suk, M.; Sulin, V. V.; Sultansoy, S.; Sumida, T.; Sun, S.; Sun, X.; Suruliz, K.; Suster, C. J. E.; Sutton, M. R.; Suzuki, S.; Svatos, M.; Swiatlowski, M.; Swift, S. P.; Sydorenko, A.; Sykora, I.; Sykora, T.; Ta, D.; Tackmann, K.; Taenzer, J.; Taffard, A.; Tafirout, R.; Taiblum, N.; Takai, H.; Takashima, R.; Takeshita, T.; Takubo, Y.; Talby, M.; Talyshev, A. A.; Tanaka, J.; Tanaka, M.; Tanaka, R.; Tanaka, S.; Tanioka, R.; Tannenwald, B. B.; Tapia Araya, S.; Tapprogge, S.; Tarem, S.; Tartarelli, G. F.; Tas, P.; Tasevsky, M.; Tashiro, T.; Tassi, E.; Tavares Delgado, A.; Tayalati, Y.; Taylor, A. C.; Taylor, G. N.; Taylor, P. T. E.; Taylor, W.; Teixeira-Dias, P.; Temple, D.; Ten Kate, H.; Teng, P. K.; Teoh, J. J.; Tepel, F.; Terada, S.; Terashi, K.; Terron, J.; Terzo, S.; Testa, M.; Teuscher, R. J.; Theveneaux-Pelzer, T.; Thomas, J. P.; Thomas-Wilsker, J.; Thompson, P. D.; Thompson, A. S.; Thomsen, L. A.; Thomson, E.; Tibbetts, M. J.; Ticse Torres, R. E.; Tikhomirov, V. O.; Tikhonov, Yu. A.; Timoshenko, S.; Tipton, P.; Tisserant, S.; Todome, K.; Todorova-Nova, S.; Tojo, J.; Tokár, S.; Tokushuku, K.; Tolley, E.; Tomlinson, L.; Tomoto, M.; Tompkins, L.; Toms, K.; Tong, B.; Tornambe, P.; Torrence, E.; Torres, H.; Torró Pastor, E.; Toth, J.; Touchard, F.; Tovey, D. R.; Treado, C. J.; Trefzger, T.; Tricoli, A.; Trigger, I. M.; Trincaz-Duvoid, S.; Tripiana, M. F.; Trischuk, W.; Trocmé, B.; Trofymov, A.; Troncon, C.; Trottier-McDonald, M.; Trovatelli, M.; Truong, L.; Trzebinski, M.; Trzupek, A.; Tsang, K. W.; Tseng, J. C.-L.; Tsiareshka, P. V.; Tsipolitis, G.; Tsirintanis, N.; Tsiskaridze, S.; Tsiskaridze, V.; Tskhadadze, E. G.; Tsui, K. M.; Tsukerman, I. I.; Tsulaia, V.; Tsuno, S.; Tsybychev, D.; Tu, Y.; Tudorache, A.; Tudorache, V.; Tulbure, T. T.; Tuna, A. N.; Tupputi, S. A.; Turchikhin, S.; Turgeman, D.; Turk Cakir, I.; Turra, R.; Tuts, P. M.; Ucchielli, G.; Ueda, I.; Ughetto, M.; Ukegawa, F.; Unal, G.; Undrus, A.; Unel, G.; Ungaro, F. C.; Unno, Y.; Unverdorben, C.; Urban, J.; Urquijo, P.; Urrejola, P.; Usai, G.; Usui, J.; Vacavant, L.; Vacek, V.; Vachon, B.; Valderanis, C.; Valdes Santurio, E.; Valencic, N.; Valentinetti, S.; Valero, A.; Valéry, L.; Valkar, S.; Vallier, A.; Valls Ferrer, J. A.; van den Wollenberg, W.; van der Graaf, H.; van Eldik, N.; van Gemmeren, P.; van Nieuwkoop, J.; van Vulpen, I.; van Woerden, M. C.; Vanadia, M.; Vandelli, W.; Vanguri, R.; Vaniachine, A.; Vankov, P.; Vardanyan, G.; Vari, R.; Varnes, E. W.; Varni, C.; Varol, T.; Varouchas, D.; Vartapetian, A.; Varvell, K. E.; Vasquez, J. G.; Vasquez, G. A.; Vazeille, F.; Vazquez Schroeder, T.; Veatch, J.; Veeraraghavan, V.; Veloce, L. M.; Veloso, F.; Veneziano, S.; Ventura, A.; Venturi, M.; Venturi, N.; Venturini, A.; Vercesi, V.; Verducci, M.; Verkerke, W.; Vermeulen, J. C.; Vetterli, M. C.; Viaux Maira, N.; Viazlo, O.; Vichou, I.; Vickey, T.; Vickey Boeriu, O. E.; Viehhauser, G. H. A.; Viel, S.; Vigani, L.; Villa, M.; Villaplana Perez, M.; Vilucchi, E.; Vincter, M. G.; Vinogradov, V. B.; Vishwakarma, A.; Vittori, C.; Vivarelli, I.; Vlachos, S.; Vlasak, M.; Vogel, M.; Vokac, P.; Volpi, G.; Volpi, M.; von der Schmitt, H.; von Toerne, E.; Vorobel, V.; Vorobev, K.; Vos, M.; Voss, R.; Vossebeld, J. H.; Vranjes, N.; Vranjes Milosavljevic, M.; Vrba, V.; Vreeswijk, M.; Vuillermet, R.; Vukotic, I.; Wagner, P.; Wagner, W.; Wahlberg, H.; Wahrmund, S.; Wakabayashi, J.; Walder, J.; Walker, R.; Walkowiak, W.; Wallangen, V.; Wang, C.; Wang, C.; Wang, F.; Wang, H.; Wang, H.; Wang, J.; Wang, J.; Wang, Q.; Wang, R.; Wang, S. M.; Wang, T.; Wang, W.; Wang, W.; Wang, Z.; Wanotayaroj, C.; Warburton, A.; Ward, C. P.; Wardrope, D. R.; Washbrook, A.; Watkins, P. M.; Watson, A. T.; Watson, M. F.; Watts, G.; Watts, S.; Waugh, B. M.; Webb, A. F.; Webb, S.; Weber, M. S.; Weber, S. W.; Weber, S. A.; Webster, J. S.; Weidberg, A. R.; Weinert, B.; Weingarten, J.; Weiser, C.; Weits, H.; Wells, P. S.; Wenaus, T.; Wengler, T.; Wenig, S.; Wermes, N.; Werner, M. D.; Werner, P.; Wessels, M.; Whalen, K.; Whallon, N. L.; Wharton, A. M.; White, A.; White, M. J.; White, R.; Whiteson, D.; Wickens, F. J.; Wiedenmann, W.; Wielers, M.; Wiglesworth, C.; Wiik-Fuchs, L. A. M.; Wildauer, A.; Wilk, F.; Wilkens, H. G.; Williams, H. H.; Williams, S.; Willis, C.; Willocq, S.; Wilson, J. A.; Wingerter-Seez, I.; Winklmeier, F.; Winston, O. J.; Winter, B. T.; Wittgen, M.; Wobisch, M.; Wolf, T. M. H.; Wolff, R.; Wolter, M. W.; Wolters, H.; Worm, S. D.; Wosiek, B. K.; Wotschack, J.; Woudstra, M. J.; Wozniak, K. W.; Wu, M.; Wu, S. L.; Wu, X.; Wu, Y.; Wyatt, T. R.; Wynne, B. M.; Xella, S.; Xi, Z.; Xia, L.; Xu, D.; Xu, L.; Yabsley, B.; Yacoob, S.; Yamaguchi, D.; Yamaguchi, Y.; Yamamoto, A.; Yamamoto, S.; Yamanaka, T.; Yamauchi, K.; Yamazaki, Y.; Yan, Z.; Yang, H.; Yang, H.; Yang, Y.; Yang, Z.; Yao, W.-M.; Yap, Y. C.; Yasu, Y.; Yatsenko, E.; Yau Wong, K. H.; Ye, J.; Ye, S.; Yeletskikh, I.; Yigitbasi, E.; Yildirim, E.; Yorita, K.; Yoshihara, K.; Young, C.; Young, C. J. S.; Youssef, S.; Yu, D. R.; Yu, J.; Yu, J.; Yuan, L.; Yuen, S. P. Y.; Yusuff, I.; Zabinski, B.; Zacharis, G.; Zaidan, R.; Zaitsev, A. M.; Zakharchuk, N.; Zalieckas, J.; Zaman, A.; Zambito, S.; Zanzi, D.; Zeitnitz, C.; Zeman, M.; Zemla, A.; Zeng, J. C.; Zeng, Q.; Zenin, O.; Ženiš, T.; Zerwas, D.; Zhang, D.; Zhang, F.; Zhang, G.; Zhang, H.; Zhang, J.; Zhang, L.; Zhang, L.; Zhang, M.; Zhang, R.; Zhang, R.; Zhang, X.; Zhang, Y.; Zhang, Z.; Zhao, X.; Zhao, Y.; Zhao, Z.; Zhemchugov, A.; Zhong, J.; Zhou, B.; Zhou, C.; Zhou, L.; Zhou, M.; Zhou, M.; Zhou, N.; Zhu, C. G.; Zhu, H.; Zhu, J.; Zhu, Y.; Zhuang, X.; Zhukov, K.; Zibell, A.; Zieminska, D.; Zimine, N. I.; Zimmermann, C.; Zimmermann, S.; Zinonos, Z.; Zinser, M.; Ziolkowski, M.; Živković, L.; Zobernig, G.; Zoccoli, A.; Zou, R.; Zur Nedden, M.; Zwalinski, L.

2017-09-01

Light-by-light scattering (γγ --> γγ) is a quantum-mechanical process that is forbidden in the classical theory of electrodynamics. This reaction is accessible at the Large Hadron Collider thanks to the large electromagnetic field strengths generated by ultra-relativistic colliding lead ions. Using 480 μb-1 of lead-lead collision data recorded at a centre-of-mass energy per nucleon pair of 5.02 TeV by the ATLAS detector, here we report evidence for light-by-light scattering. A total of 13 candidate events were observed with an expected background of 2.6 +/- 0.7 events. After background subtraction and analysis corrections, the fiducial cross-section of the process Pb + Pb (γγ) --> Pb(*) + Pb(*)γγ, for photon transverse energy ET > 3 GeV, photon absolute pseudorapidity |η| < 2.4, diphoton invariant mass greater than 6 GeV, diphoton transverse momentum lower than 2 GeV and diphoton acoplanarity below 0.01, is measured to be 70 +/- 24 (stat.) +/- 17 (syst.) nb, which is in agreement with the standard model predictions.

Nocturnality constrains morphological and functional diversity in the eyes of reef fishes

PubMed Central

2011-01-01

Background Ambient light levels are often considered to drive the evolution of eye form and function. Diel activity pattern is the main mechanism controlling the visual environment of teleost reef fish, with day-active (diurnal) fish active in well-illuminated conditions, whereas night-active (nocturnal) fish cope with dim light. Physiological optics predicts several specific evolutionary responses to dim-light vision that should be reflected in visual performance features of the eye. Results We analyzed a large comparative dataset on morphological traits of the eyes in 265 species of teleost reef fish in 43 different families. The eye morphology of nocturnal reef teleosts is characterized by a syndrome that indicates better light sensitivity, including large relative eye size, high optical ratio and large, rounded pupils. Improved dim-light image formation comes at the cost of reduced depth of focus and reduction of potential accommodative lens movement. Diurnal teleost reef fish, released from the stringent functional requirements of dim-light vision have much higher morphological and optical diversity than nocturnal species, with large ranges of optical ratio, depth of focus, and lens accommodation. Conclusions Physical characteristics of the environment are an important factor in the evolution and diversification of the vertebrate eye. Both teleost reef fish and terrestrial amniotes meet the functional requirements of dim-light vision with a similar evolutionary response of morphological and optical modifications. The trade-off between improved dim-light vision and reduced optical diversity may be a key factor in explaining the lower trophic diversity of nocturnal reef teleosts. PMID:22098687

AdS/QCD and Applications of Light-Front Holography

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

Brodsky, Stanley J.; /SLAC /Southern Denmark U., CP3-Origins; Cao, Fu-Guang

2012-02-16

Light-Front Holography leads to a rigorous connection between hadronic amplitudes in a higher dimensional anti-de Sitter (AdS) space and frame-independent light-front wavefunctions of hadrons in 3 + 1 physical space-time, thus providing a compelling physical interpretation of the AdS/CFT correspondence principle and AdS/QCD, a useful framework which describes the correspondence between theories in a modified AdS5 background and confining field theories in physical space-time. To a first semiclassical approximation, where quantum loops and quark masses are not included, this approach leads to a single-variable light-front Schroedinger equation which determines the eigenspectrum and the light-front wavefunctions of hadrons for general spinmore » and orbital angular momentum. The coordinate z in AdS space is uniquely identified with a Lorentz-invariant coordinate {zeta} which measures the separation of the constituents within a hadron at equal light-front time. The internal structure of hadrons is explicitly introduced and the angular momentum of the constituents plays a key role. We give an overview of the light-front holographic approach to strongly coupled QCD. In particular, we study the photon-to-meson transition form factors (TFFs) F{sub M{gamma}}(Q{sup 2}) for {gamma}{gamma}* {yields} M using light-front holographic methods. The results for the TFFs for the {eta} and {eta}' mesons are also presented. Some novel features of QCD are discussed, including the consequences of confinement for quark and gluon condensates. A method for computing the hadronization of quark and gluon jets at the amplitude level is outlined.« less

Binarization algorithm for document image with complex background

NASA Astrophysics Data System (ADS)

Miao, Shaojun; Lu, Tongwei; Min, Feng

2015-12-01

The most important step in image preprocessing for Optical Character Recognition (OCR) is binarization. Due to the complex background or varying light in the text image, binarization is a very difficult problem. This paper presents the improved binarization algorithm. The algorithm can be divided into several steps. First, the background approximation can be obtained by the polynomial fitting, and the text is sharpened by using bilateral filter. Second, the image contrast compensation is done to reduce the impact of light and improve contrast of the original image. Third, the first derivative of the pixels in the compensated image are calculated to get the average value of the threshold, then the edge detection is obtained. Fourth, the stroke width of the text is estimated through a measuring of distance between edge pixels. The final stroke width is determined by choosing the most frequent distance in the histogram. Fifth, according to the value of the final stroke width, the window size is calculated, then a local threshold estimation approach can begin to binaries the image. Finally, the small noise is removed based on the morphological operators. The experimental result shows that the proposed method can effectively remove the noise caused by complex background and varying light.

Peculiar Features in Patterns of Ancient Light

NASA Image and Video Library

2013-03-21

ESA Planck mission has imaged the oldest light in our universe. The top map shows Planck all-sky map of the cosmic microwave background, whereas the bottom map shows the largest-scale features of the map.

Opacity meter for monitoring exhaust emissions from non-stationary sources

DOEpatents

Dec, John Edward

2000-01-01

Method and apparatus for determining the opacity of exhaust plumes from moving emissions sources. In operation, a light source is activated at a time prior to the arrival of a diesel locomotive at a measurement point, by means of a track trigger switch or the Automatic Equipment Identification system, such that the opacity measurement is synchronized with the passage of an exhaust plume past the measurement point. A beam of light from the light source passes through the exhaust plume of the locomotive and is detected by a suitable detector, preferably a high-rate photodiode. The light beam is well-collimated and is preferably monochromatic, permitting the use of a narrowband pass filter to discriminate against background light. In order to span a double railroad track and provide a beam which is substantially stronger than background, the light source, preferably a diode laser, must provide a locally intense beam. A high intensity light source is also desirable in order to increase accuracy at the high sampling rates required. Also included is a computer control system useful for data acquisition, manipulation, storage and transmission of opacity data and the identification of the associated diesel engine to a central data collection center.

Flight Calibration of the LROC Narrow Angle Camera

NASA Astrophysics Data System (ADS)

Humm, D. C.; Tschimmel, M.; Brylow, S. M.; Mahanti, P.; Tran, T. N.; Braden, S. E.; Wiseman, S.; Danton, J.; Eliason, E. M.; Robinson, M. S.

2016-04-01

Characterization and calibration are vital for instrument commanding and image interpretation in remote sensing. The Lunar Reconnaissance Orbiter Camera Narrow Angle Camera (LROC NAC) takes 500 Mpixel greyscale images of lunar scenes at 0.5 meters/pixel. It uses two nominally identical line scan cameras for a larger crosstrack field of view. Stray light, spatial crosstalk, and nonlinearity were characterized using flight images of the Earth and the lunar limb. These are important for imaging shadowed craters, studying ˜1 meter size objects, and photometry respectively. Background, nonlinearity, and flatfield corrections have been implemented in the calibration pipeline. An eight-column pattern in the background is corrected. The detector is linear for DN = 600--2000 but a signal-dependent additive correction is required and applied for DN<600. A predictive model of detector temperature and dark level was developed to command dark level offset. This avoids images with a cutoff at DN=0 and minimizes quantization error in companding. Absolute radiometric calibration is derived from comparison of NAC images with ground-based images taken with the Robotic Lunar Observatory (ROLO) at much lower spatial resolution but with the same photometric angles.

Stochastic gravitational wave background from light cosmic strings

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

DePies, Matthew R.; Hogan, Craig J.

2007-06-15

Spectra of the stochastic gravitational wave backgrounds from cosmic strings are calculated and compared with present and future experimental limits. Motivated by theoretical expectations of light cosmic strings in superstring cosmology, improvements in experimental sensitivity, and recent demonstrations of large, stable loop formation from a primordial network, this study explores a new range of string parameters with masses lighter than previously investigated. A standard 'one-scale' model for string loop formation is assumed. Background spectra are calculated numerically for dimensionless string tensions G{mu}/c{sup 2} between 10{sup -7} and 10{sup -18}, and initial loop sizes as a fraction of the Hubble radiusmore » {alpha} from 0.1 to 10{sup -6}. The spectra show a low frequency power-law tail, a broad spectral peak due to loops decaying at the present epoch (including frequencies higher than their fundamental mode, and radiation associated with cusps), and a flat (constant energy density) spectrum at high frequencies due to radiation from loops that decayed during the radiation-dominated era. The string spectrum is distinctive and unlike any other known source. The peak of the spectrum for light strings appears at high frequencies, significantly affecting predicted signals. The spectra of the cosmic string backgrounds are compared with current millisecond pulsar limits and Laser Interferometer Space Antenna (LISA) sensitivity curves. For models with large stable loops ({alpha}=0.1), current pulsar-timing limits exclude G{mu}/c{sup 2}>10{sup -9}, a much tighter limit on string tension than achievable with other techniques, and within the range of current models based on brane inflation. LISA may detect a background from strings as light as G{mu}/c{sup 2}{approx_equal}10{sup -16}, corresponding to field theory strings formed at roughly 10{sup 11} GeV.« less

A Heuristic Approach to Remove the Background Intensity on White-light Solar Images. I. STEREO /HI-1 Heliospheric Images

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

Stenborg, Guillermo; Howard, Russell A.

White-light coronal and heliospheric imagers observe scattering of photospheric light from both dust particles (the F-Corona) and free electrons in the corona (the K-corona). The separation of the two coronae is thus vitally important to reveal the faint K-coronal structures (e.g., streamers, co-rotating interaction regions, coronal mass ejections, etc.). However, the separation of the two coronae is very difficult, so we are content in defining a background corona that contains the F- and as little K- as possible. For both the LASCO-C2 and LASCO-C3 coronagraphs aboard the Solar and Heliospheric Observatory ( SOHO ) and the white-light imagers of themore » SECCHI suite aboard the Solar Terrestrial Relationships Observatory ( STEREO ), a time-dependent model of the background corona is generated from about a month of similar images. The creation of such models is possible because the missions carrying these instruments are orbiting the Sun at about 1 au. However, the orbit profiles for the upcoming Solar Orbiter and Solar Probe Plus missions are very different. These missions will have elliptic orbits with a rapidly changing radial distance, hence invalidating the techniques in use for the SOHO /LASCO and STEREO /SECCHI instruments. We have been investigating techniques to generate background models out of just single images that could be used for the Solar Orbiter Heliospheric Imager and the Wide-field Imager for the Solar Probe Plus packages on board the respective spacecraft. In this paper, we introduce a state-of-the-art, heuristic technique to create the background intensity models of STEREO /HI-1 data based solely on individual images, report on new results derived from its application, and discuss its relevance to instrumental and operational issues.« less

Ultraviolet stress delays chromosome replication in light/dark synchronized cells of the marine cyanobacterium Prochlorococcus marinus PCC9511

PubMed Central

2010-01-01

Background The marine cyanobacterium Prochlorococcus is very abundant in warm, nutrient-poor oceanic areas. The upper mixed layer of oceans is populated by high light-adapted Prochlorococcus ecotypes, which despite their tiny genome (~1.7 Mb) seem to have developed efficient strategies to cope with stressful levels of photosynthetically active and ultraviolet (UV) radiation. At a molecular level, little is known yet about how such minimalist microorganisms manage to sustain high growth rates and avoid potentially detrimental, UV-induced mutations to their DNA. To address this question, we studied the cell cycle dynamics of P. marinus PCC9511 cells grown under high fluxes of visible light in the presence or absence of UV radiation. Near natural light-dark cycles of both light sources were obtained using a custom-designed illumination system (cyclostat). Expression patterns of key DNA synthesis and repair, cell division, and clock genes were analyzed in order to decipher molecular mechanisms of adaptation to UV radiation. Results The cell cycle of P. marinus PCC9511 was strongly synchronized by the day-night cycle. The most conspicuous response of cells to UV radiation was a delay in chromosome replication, with a peak of DNA synthesis shifted about 2 h into the dark period. This delay was seemingly linked to a strong downregulation of genes governing DNA replication (dnaA) and cell division (ftsZ, sepF), whereas most genes involved in DNA repair (such as recA, phrA, uvrA, ruvC, umuC) were already activated under high visible light and their expression levels were only slightly affected by additional UV exposure. Conclusions Prochlorococcus cells modified the timing of the S phase in response to UV exposure, therefore reducing the risk that mutations would occur during this particularly sensitive stage of the cell cycle. We identified several possible explanations for the observed timeshift. Among these, the sharp decrease in transcript levels of the dnaA gene, encoding the DNA replication initiator protein, is sufficient by itself to explain this response, since DNA synthesis starts only when the cellular concentration of DnaA reaches a critical threshold. However, the observed response likely results from a more complex combination of UV-altered biological processes. PMID:20670397

A novel, cost-effective, multi-point Thomson scattering system on the Pegasus Toroidal Experiment (invited)

DOE PAGES

Schlossberg, David J.; Bodner, Grant M.; Bongard, Michael W.; ...

2016-09-16

Here, a novel, cost-effective, multi-point Thomson scattering system has been designed, implemented, and operated on the Pegasus Toroidal Experiment. Leveraging advances in Nd:YAG lasers, high-efficiency volume phase holographic transmission gratings, and increased quantum-efficiency Generation 3 image-intensified charge coupled device (ICCD) cameras, the system provides Thomson spectra at eight spatial locations for a single grating/camera pair. The on-board digitization of the ICCD camera enables easy modular expansion, evidenced by recent extension from 4 to 12 plasma/background spatial location pairs. Stray light is rejected using time-of-flight methods suited to gated ICCDs, and background light is blocked during detector readout by a fastmore » shutter. This –10 3 reduction in background light enables further expansion to up to 24 spatial locations. The implementation now provides single-shot T e(R) for n e > 5 × 10 18 m –3.« less

Temperature dependence of alpha-induced scintillation in the 1,1,4,4-tetraphenyl-1,3-butadiene wavelength shifter

NASA Astrophysics Data System (ADS)

Veloce, L. M.; Kuźniak, M.; Di Stefano, P. C. F.; Noble, A. J.; Boulay, M. G.; Nadeau, P.; Pollmann, T.; Clark, M.; Piquemal, M.; Schreiner, K.

2016-06-01

Liquid noble based particle detectors often use the organic wavelength shifter 1,1,4,4-tetraphenyl-1,3-butadiene (TPB) which shifts UV scintillation light to the visible regime, facilitating its detection, but which also can scintillate on its own. Dark matter searches based on this type of detector commonly rely on pulse-shape discrimination (PSD) for background mitigation. Alpha-induced scintillation therefore represents a possible background source in dark matter searches. The timing characteristics of this scintillation determine whether this background can be mitigated through PSD. We have therefore characterized the pulse shape and light yield of alpha induced TPB scintillation at temperatures ranging from 300 K down to 4 K, with special attention given to liquid noble gas temperatures. We find that the pulse shapes and light yield depend strongly on temperature. In addition, the significant contribution of long time constants above ~50 K provides an avenue for discrimination between alpha decay events in TPB and nuclear-recoil events in noble liquid detectors.

Rod-cone interaction in light adaptation

PubMed Central

Latch, M.; Lennie, P.

1977-01-01

1. The increment-threshold for a small test spot in the peripheral visual field was measured against backgrounds that were red or blue. 2. When the background was a large uniform field, threshold over most of the scotopic range depended exactly upon the background's effect upon rods. This confirms Flamant & Stiles (1948). But when the background was small, threshold was elevated more by a long wave-length than a short wave-length background equated for its effect on rods. 3. The influence of cones was explored in a further experiment. The scotopic increment-threshold was established for a short wave-length test spot on a large, short wave-length background. Then a steady red circular patch, conspicuous to cones, but below the increment-threshold for rod vision, was added to the background. When it was small, but not when it was large, this patch substantially raised the threshold for the test. 4. When a similar experiment was made using, instead of a red patch, a short wave-length one that was conspicuous in rod vision, threshold varied similarly with patch size. These results support the notion that the influence of small backgrounds arises in some size-selective mechanism that is indifferent to the receptor system in which visual signals originate. Two corollaries of this hypothesis were tested in further experiments. 5. A small patch was chosen so as to lift scotopic threshold substantially above its level on a uniform field. This threshold elevation persisted for minutes after extinction of the patch, but only when the patch was small. A large patch made bright enough to elevate threshold by as much as the small one gave rise to no corresponding after-effect. 6. Increment-thresholds for a small red test spot, detected through cones, followed the same course whether a large uniform background was long- or short wave-length. When the background was small, threshold upon the short wave-length one began to rise for much lower levels of background illumination, suggesting the influence of rods. This was confirmed by repeating the experiment after a strong bleach when the cones, but not rods, had fully recovered their sensitivity. Increment-thresholds upon small backgrounds of long or short wave-lengths then followed the same course. PMID:894602

Document segmentation for high-quality printing

NASA Astrophysics Data System (ADS)

Ancin, Hakan

1997-04-01

A technique to segment dark texts on light background of mixed mode color documents is presented. This process does not perceptually change graphics and photo regions. Color documents are scanned and printed from various media which usually do not have clean background. This is especially the case for the printouts generated from thin magazine samples, these printouts usually include text and figures form the back of the page, which is called bleeding. Removal of bleeding artifacts improves the perceptual quality of the printed document and reduces the color ink usage. By detecting the light background of the document, these artifacts are removed from background regions. Also detection of dark text regions enables the halftoning algorithms to use true black ink for the black text pixels instead of composite black. The processed document contains sharp black text on white background, resulting improved perceptual quality and better ink utilization. The described method is memory efficient and requires a small number of scan lines of high resolution color documents during processing.

The Universe's First Fireworks

NASA Technical Reports Server (NTRS)

2006-01-01

[figure removed for brevity, see original site] [figure removed for brevity, see original site] [figure removed for brevity, see original site] Poster VersionFigure 1Figure 2

This is an image from NASA's Spitzer Space Telescope of stars and galaxies in the Ursa Major constellation. This infrared image covers a region of space so large that light would take up to 100 million years to travel across it. Figure 1 is the same image after stars, galaxies and other sources were masked out. The remaining background light is from a period of time when the universe was less than one billion years old, and most likely originated from the universe's very first groups of objects -- either huge stars or voracious black holes. Darker shades in the image on the left correspond to dimmer parts of the background glow, while yellow and white show the brightest light.

Brief History of the Universe In figure 2, the artist's timeline chronicles the history of the universe, from its explosive beginning to its mature, present-day state.

Our universe began in a tremendous explosion known as the Big Bang about 13.7 billion years ago (left side of strip). Observations by NASA's Cosmic Background Explorer and Wilkinson Anisotropy Microwave Probe revealed microwave light from this very early epoch, about 400,000 years after the Big Bang, providing strong evidence that our universe did blast into existence. Results from the Cosmic Background Explorer were honored with the 2006 Nobel Prize for Physics.

A period of darkness ensued, until about a few hundred million years later, when the first objects flooded the universe with light. This first light is believed to have been captured in data from NASA's Spitzer Space Telescope. The light detected by Spitzer would have originated as visible and ultraviolet light, then stretched, or redshifted, to lower-energy infrared wavelengths during its long voyage to reach us across expanding space. The light detected by the Cosmic Background Explorer and the Wilkinson Anisotropy Microwave Probe from our very young universe traveled farther to reach us, and stretched to even lower-energy microwave wavelengths.

Astronomers do not know if the very first objects were either stars or quasars. The first stars, called Population III stars (our star is a Population I star), were much bigger and brighter than any in our nearby universe, with masses about 1,000 times that of our sun. These stars first grouped together into mini-galaxies. By about a few billion years after the Big Bang, the mini-galaxies had merged to form mature galaxies, including spiral galaxies like our own Milky Way. The first quasars ultimately became the centers of powerful galaxies that are more common in the distant universe.

NASA's Hubble Space Telescope has captured stunning pictures of earlier galaxies, as far back as ten billion light-years away.

Multimodal Imaging and Lighting Bias Correction for Improved μPAD-based Water Quality Monitoring via Smartphones

NASA Astrophysics Data System (ADS)

McCracken, Katherine E.; Angus, Scott V.; Reynolds, Kelly A.; Yoon, Jeong-Yeol

2016-06-01

Smartphone image-based sensing of microfluidic paper analytical devices (μPADs) offers low-cost and mobile evaluation of water quality. However, consistent quantification is a challenge due to variable environmental, paper, and lighting conditions, especially across large multi-target μPADs. Compensations must be made for variations between images to achieve reproducible results without a separate lighting enclosure. We thus developed a simple method using triple-reference point normalization and a fast-Fourier transform (FFT)-based pre-processing scheme to quantify consistent reflected light intensity signals under variable lighting and channel conditions. This technique was evaluated using various light sources, lighting angles, imaging backgrounds, and imaging heights. Further testing evaluated its handle of absorbance, quenching, and relative scattering intensity measurements from assays detecting four water contaminants - Cr(VI), total chlorine, caffeine, and E. coli K12 - at similar wavelengths using the green channel of RGB images. Between assays, this algorithm reduced error from μPAD surface inconsistencies and cross-image lighting gradients. Although the algorithm could not completely remove the anomalies arising from point shadows within channels or some non-uniform background reflections, it still afforded order-of-magnitude quantification and stable assay specificity under these conditions, offering one route toward improving smartphone quantification of μPAD assays for in-field water quality monitoring.

Atmospheric mercury emissions from mine wastes and surrounding geologically enriched terrains

USGS Publications Warehouse

Gustin, M.S.; Coolbaugh, M.F.; Engle, M.A.; Fitzgerald, B.C.; Keislar, R.E.; Lindberg, S.E.; Nacht, D.M.; Quashnick, J.; Rytuba, J.J.; Sladek, C.; Zhang, H.; Zehner, R.E.

2003-01-01

Waste rock and ore associated with Hg, precious and base metal mining, and their surrounding host rocks are typically enriched in mercury relative to natural background concentrations (<0.1 ??g Hg g-1). Mercury fluxes to the atmosphere from mineralized areas can range from background rates (0-15 ng m-2 h-1) to tens of thousands of ng m-2 h-1. Mercury enriched substrate constitutes a long-term source of mercury to the global atmospheric mercury pool. Mercury emissions from substrate are influenced by light, temperature, precipitation, and substrate mercury concentration, and occur during the day and night. Light-enhanced emissions are driven by two processes: desorption of elemental mercury accumulated at the soil:air interface, and photo reduction of mercury containing phases. To determine the need for and effectiveness of regulatory controls on short-lived anthropogenic point sources the contribution of mercury from geologic non-point sources to the atmospheric mercury pool needs to be quantified. The atmospheric mercury contribution from small areas of mining disturbance with relatively high mercury concentrations are, in general, less than that from surrounding large areas of low levels of mercury enrichment. In the arid to semi-arid west-ern United States volatilization is the primary means by which mercury is released from enriched sites.

Camera/Photometer Results

NASA Astrophysics Data System (ADS)

Clifton, K. S.; Owens, J. K.

1983-04-01

Efforts continue regarding the analysis of particulate contamination recorded by the Camera/Photometers on STS-2. These systems were constructed by Epsilon Laboratories, Inc. and consisted of two 16-mm photographic cameras, using Kodak Double X film, Type 7222, to make stereoscopic observations of contaminant particles and background. Each was housed within a pressurized canister and operated automatically throughout the mission, making simultaneous exposures on a continuous basis every 150 sec. The cameras were equipped with 18-mm f/0.9 lenses and subtended overlapping 20° fields-of-view. An integrating photometer was used to inhibit the exposure sequences during periods of excessive illumination and to terminate the exposures at preset light levels. During the exposures, a camera shutter operated in a chopping mode in order to isolate the movement of particles for velocity determinations. Calculations based on the preflight film calibration indicate that particles as small as 25 μm can be detected from ideal observing conditions. Current emphasis is placed on the digitization of the photographic data frames and the determination of particle distances, sizes, and velocities. It has been concluded that background bright-ness measurements cannot be established with any reliability on the STS-2 mission, due to the preponderance of Earth-directed attitudes and the incidence of light reflected from nearby surfaces.

The effects of diurnal intermittent fasting on the wake-promoting neurotransmitter orexin-A

PubMed Central

Almeneessier, Aljohara S.; Alzoghaibi, Mohammed; BaHammam, Abdulrahman A.; Ibrahim, Mahmoud G.; Olaish, Awad H.; Nashwan, Samar Z.; BaHammam, Ahmed S.

2018-01-01

BACKGROUND: Food restriction has been demonstrated to increase the alertness in different species and to increase the levels of the wake-promoting neurotransmitter orexin. We hypothesized that diurnal intermittent fasting (DIF) increases orexin-A levels during fasting. Therefore, we conducted this study to assess the effects of DIF, during the month of Ramadan, on orexin, while controlling for lifestyle changes that may accompany Ramadan such as sleep duration, bedtime and wake time, energy expenditure, light exposure, and food. METHODS: Eight young healthy volunteers (mean age, 25.4 ± 3.5 years) reported to the laboratory on three occasions: (1) 4 weeks before Ramadan while performing DIF for 1 week outside the month of Ramadan (fasting outside Ramadan); (2) 1 week before Ramadan (nonfasting baseline) (BL); and (3) during the 2nd week of Ramadan while performing DIF (Ramadan). Plasma levels of orexin-A were measured using an enzyme immunoassay five times at 22:00, 02:00, 04:00, 06:00, and 11:00. Caloric intake, light exposure, and sleep schedule were maintained during the participants’ stays in the laboratory in the three study periods. RESULTS: Orexin-A levels increased in the daytime during fasting and decreased at night compared to BL. The differences in orexin-A levels between DIF and BL were significant at 06:00, 11:00, 22:00, and 02:00. CONCLUSIONS: DIF increases orexin-A levels in the plasma during fasting hours. This finding supports findings from animal studies showing that fasting increases alertness. PMID:29387256

Exploring Relationships between Canopy Architecture, Light Distribution, and Photosynthesis in Contrasting Rice Genotypes Using 3D Canopy Reconstruction

PubMed Central

Burgess, Alexandra J.; Retkute, Renata; Herman, Tiara; Murchie, Erik H.

2017-01-01

The arrangement of leaf material is critical in determining the light environment, and subsequently the photosynthetic productivity of complex crop canopies. However, links between specific canopy architectural traits and photosynthetic productivity across a wide genetic background are poorly understood for field grown crops. The architecture of five genetically diverse rice varieties—four parental founders of a multi-parent advanced generation intercross (MAGIC) population plus a high yielding Philippine variety (IR64)—was captured at two different growth stages using a method for digital plant reconstruction based on stereocameras. Ray tracing was employed to explore the effects of canopy architecture on the resulting light environment in high-resolution, whilst gas exchange measurements were combined with an empirical model of photosynthesis to calculate an estimated carbon gain and total light interception. To further test the impact of different dynamic light patterns on photosynthetic properties, an empirical model of photosynthetic acclimation was employed to predict the optimal light-saturated photosynthesis rate (Pmax) throughout canopy depth, hypothesizing that light is the sole determinant of productivity in these conditions. First, we show that a plant type with steeper leaf angles allows more efficient penetration of light into lower canopy layers and this, in turn, leads to a greater photosynthetic potential. Second the predicted optimal Pmax responds in a manner that is consistent with fractional interception and leaf area index across this germplasm. However, measured Pmax, especially in lower layers, was consistently higher than the optimal Pmax indicating factors other than light determine photosynthesis profiles. Lastly, varieties with more upright architecture exhibit higher maximum quantum yield of photosynthesis indicating a canopy-level impact on photosynthetic efficiency. PMID:28567045

Tailored lighting intervention improves measures of sleep, depression, and agitation in persons with Alzheimer’s disease and related dementia living in long-term care facilities

PubMed Central

Figueiro, Mariana G; Plitnick, Barbara A; Lok, Anna; Jones, Geoffrey E; Higgins, Patricia; Hornick, Thomas R; Rea, Mark S

2014-01-01

Background Light therapy has shown great promise as a nonpharmacological method to improve symptoms associated with Alzheimer’s disease and related dementias (ADRD), with preliminary studies demonstrating that appropriately timed light exposure can improve nighttime sleep efficiency, reduce nocturnal wandering, and alleviate evening agitation. Since the human circadian system is maximally sensitive to short-wavelength (blue) light, lower, more targeted lighting interventions for therapeutic purposes, can be used. Methods The present study investigated the effectiveness of a tailored lighting intervention for individuals with ADRD living in nursing homes. Low-level “bluish-white” lighting designed to deliver high circadian stimulation during the daytime was installed in 14 nursing home resident rooms for a period of 4 weeks. Light–dark and rest–activity patterns were collected using a Daysimeter. Sleep time and sleep efficiency measures were obtained using the rest–activity data. Measures of sleep quality, depression, and agitation were collected using standardized questionnaires, at baseline, at the end of the 4-week lighting intervention, and 4 weeks after the lighting intervention was removed. Results The lighting intervention significantly (P<0.05) decreased global sleep scores from the Pittsburgh Sleep Quality Index, and increased total sleep time and sleep efficiency. The lighting intervention also increased phasor magnitude, a measure of the 24-hour resonance between light–dark and rest–activity patterns, suggesting an increase in circadian entrainment. The lighting intervention significantly (P<0.05) reduced depression scores from the Cornell Scale for Depression in Dementia and agitation scores from the Cohen–Mansfield Agitation Inventory. Conclusion A lighting intervention, tailored to increase daytime circadian stimulation, can be used to increase sleep quality and improve behavior in patients with ADRD. The present field study, while promising for application, should be replicated using a larger sample size and perhaps using longer treatment duration. PMID:25246779

Refinement of a limit cycle oscillator model of the effects of light on the human circadian pacemaker

NASA Technical Reports Server (NTRS)

Jewett, M. E.; Kronauer, R. E.; Brown, E. N. (Principal Investigator)

1998-01-01

In 1990, Kronauer proposed a mathematical model of the effects of light on the human circadian pacemaker. Although this model predicted many general features of the response of the human circadian pacemaker to light exposure, additional data now available enable us to refine the original model. We first refined the original model by incorporating the results of a dose response curve to light into the model's predicted relationship between light intensity and the strength of the drive onto the pacemaker. Data from three bright light phase resetting experiments were then used to refine the amplitude recovery characteristics of the model. Finally, the model was tested and further refined using data from an extensive phase resetting experiment in which a 3-cycle bright light stimulus was presented against a background of dim light. In order to describe the results of the four resetting experiments, the following major refinements to the original model were necessary: (i) the relationship between light intensity (I) and drive onto the pacemaker was reduced from I1/3 to I0.23 for light levels between 150 and 10,000 lux; (ii) the van der Pol oscillator from the original model was replaced with a higher-order limit cycle oscillator so that amplitude recovery is slower near the singularity and faster near the limit cycle; (iii) a direct effect of light on circadian period (tau x) was incorporated into the model such that as I increases, tau x decreases, which is in accordance with "Aschoff's rule". This refined model generates the following testable predictions: it should be difficult to enhance normal circadian amplitude via bright light; near the critical point of a type 0 phase response curve (PRC) the slope should be steeper than it is in a type 1 PRC; and circadian period measured during forced desynchrony should be directly affected by ambient light intensity.

Fun House Mirror in Space

NASA Image and Video Library

2010-08-19

NASA Hubble Space Telescope shows the inner region of Abell 1689, an immense cluster of galaxies located 2.2 billion light-years away. The cluster gravitational field is warping light from background galaxies, causing them to appear as arcs.

Super-quenched Molecular Probe Based on Aggregation-Induced Emission and Photoinduced Electron Transfer Mechanisms for Formaldehyde Detection in Human Serum.

PubMed

Yang, Haitao; Wang, Fujia; Zheng, Jilin; Lin, Hao; Liu, Bin; Tang, Yi-Da; Zhang, Chong-Jing

2018-06-04

Energy transfer between fluorescent dyes and quenchers is widely used in the design of light-up probes. Although dual quenchers are more effective in offering lower background signals and higher turn-on ratios than one quencher, such probes are less explored in practice as they require both quenchers to be within the proximity of the fluorescent core. In this contribution, we utilized intramolecular motion and photoinduced electron transfer (PET) as quenching mechanisms to build super-quenched light-up probes based on fluorogens with aggregation-induced emission. The optimized light-up probe possesses negligible background and is able to detect not only free formaldehyde (FA) but also polymeric FA, with an unprecedented turn-on ratio of >4900. We envision that this novel dual quenching strategy will help to develop various light-up probes for analyte sensing. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

PRAXIS: a low background NIR spectrograph for fibre Bragg grating OH suppression

NASA Astrophysics Data System (ADS)

Horton, Anthony; Ellis, Simon; Lawrence, Jon; Bland-Hawthorn, Joss

2012-09-01

Fibre Bragg grating (FBG) OH suppression is capable of greatly reducing the bright sky background seen by near infrared spectrographs. By filtering out the airglow emission lines at high resolution before the light enters the spectrograph this technique prevents scattering from the emission lines into interline regions, thereby reducing the background at all wavelengths. In order to take full advantage of this sky background reduction the spectrograph must have very low instrumental backgrounds so that it remains sky noise limited. Both simulations and real world experience with the prototype GNOSIS system show that existing spectrographs, designed for higher sky background levels, will be unable to fully exploit the sky background reduction. We therefore propose PRAXIS, a spectrograph optimised specifically for this purpose. The PRAXIS concept is a fibre fed, fully cryogenic, fixed format spectrograph for the J and H-bands. Dark current will be minimised by using the best of the latest generation of NIR detectors while thermal backgrounds will be reduced by the use of a cryogenic fibre slit. Optimised spectral formats and the use of high throughput volume phase holographic gratings will further enhance sensitivity. Our proposal is for a modular system, incorporating exchangeable fore-optics units, integral field units and OH suppression units, to allow PRAXIS to operate as a visitor instrument on any large telescope and enable new developments in FBG OH suppression to be incorporated as they become available. As a high performance fibre fed spectrograph PRAXIS could also serve as a testbed for other astrophotonic technologies.

Study of light mesons with WASA-at-COSY

NASA Astrophysics Data System (ADS)

Prencipe, Elisabetta

2014-06-01

The WASA detector, operating at the COSY facility in Jülich (Germany) has been collecting data since 2007. The experiment allows to perform studies of light mesons, such as π0, η and ω rare decay processes, in order to perform precise measurements of branching ratios, determine Dalitz plot parameters, test symmetry and symmetry breaking, and evaluate transition form factors. In the experiments a proton or deuteron beam impinged on a pellet target of hydrogen or deuterium, which allows the reactions proton-proton (pp) or proton-deuteron (pd). A high-statistics sample of η mesons has been collected: in the reaction pd →3He η, 3×107η mesons were tagged at a beam energy of 1.0 GeV, while 5×108η mesons were produced in the reaction pp → ppη at 1.4 GeV. This corresponds to the production of 10 η/s and 100 η/s, respectively, for the two reaction processes. In the pp dataset a higher background level is found compared to the pd data set. In both cases, we identify the η mesons by means of the missing mass derived from the recoil particles. A kinematic fit largely rejects the background in our analysis. The advantage in using the pp dataset is that the production of η mesons is almost a factor of 10 higher than in the pd fusion to 3He. As we plan to measure the branching ratios of very rare processes, high statistics is needed. A summary of the recent activity on the study of light mesons with WASA-at-COSY here is given.

Dust lanes in backlit galaxies: first results from the STARSMOG survey

NASA Astrophysics Data System (ADS)

Keel, William C.; Bradford, Sarah; Holwerda, Benne; Conselice, Christopher; Baldry, Ivan; Bland-Hawthorn, Jonathan; Driver, Simon P.; Dunne, Loretta; Liske, Jochen; Robotham, Aaron; Tuffs, Richard

2017-01-01

STARSMOG is an HST WFC3 snapshot survey of dust attenuation in overlapping backlit galaxies, planned to span the range of morphological type and luminosity of dust-rich galaxies. The target list came from the Galaxy Zoo and GAMA catalogs, imposing a minimum redshift difference to guarantee large line-of-sight separations, virtually eliminating scattering corrections and avoiding potentially distorted interacting systems. These include the first flocculent spirals studied with the occulting-galaxy approach. We present results from the geometrically most favorable subset of 9 pairs from the 54 observed STARSMOG systems. The data quality and intensity of background light let us map dust features with attenuations of only a few per cent in the red F606W band. Organized dust lanes show sharp outer boundaries in disks, and are absent in galaxies of late Hubble type. Many Sb-Sc disks show a dusty web of criss-crossing lanes, some nearly at right angles to the overall spiral pattern. Particularly favorable cases constraint the scale height of starlight in the foreground disks, through comparison of the light loss in regions with and without background light. The covering fraction of dust at various attenuation levels is consistent between barred and nonbarred spirals, although dust features may be more concentrated in azimuth when a bar is present (and concentrated in an annulus when a stellar resonance ring is seen). Together with our previous data on much more limited samples or at lower resolution,these results add to a picture where galaxies of similar morphology may have quite different attenuation patterns with radius for both arm and interarm dust.

Green light for quantitative live-cell imaging in plants.

PubMed

Grossmann, Guido; Krebs, Melanie; Maizel, Alexis; Stahl, Yvonne; Vermeer, Joop E M; Ott, Thomas

2018-01-29

Plants exhibit an intriguing morphological and physiological plasticity that enables them to thrive in a wide range of environments. To understand the cell biological basis of this unparalleled competence, a number of methodologies have been adapted or developed over the last decades that allow minimal or non-invasive live-cell imaging in the context of tissues. Combined with the ease to generate transgenic reporter lines in specific genetic backgrounds or accessions, we are witnessing a blooming in plant cell biology. However, the imaging of plant cells entails a number of specific challenges, such as high levels of autofluorescence, light scattering that is caused by cell walls and their sensitivity to environmental conditions. Quantitative live-cell imaging in plants therefore requires adapting or developing imaging techniques, as well as mounting and incubation systems, such as micro-fluidics. Here, we discuss some of these obstacles, and review a number of selected state-of-the-art techniques, such as two-photon imaging, light sheet microscopy and variable angle epifluorescence microscopy that allow high performance and minimal invasive live-cell imaging in plants. © 2018. Published by The Company of Biologists Ltd.

Cumulative effects in inflation with ultra-light entropy modes

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

Achúcarro, Ana; Atal, Vicente; Germani, Cristiano

2017-02-01

In multi-field inflation one or more non-adiabatic modes may become light, potentially inducing large levels of isocurvature perturbations in the cosmic microwave background. If in addition these light modes are coupled to the adiabatic mode, they influence its evolution on super horizon scales. Here we consider the case in which a non-adiabatic mode becomes approximately massless (''ultralight') while still coupled to the adiabatic mode, a typical situation that arises with pseudo-Nambu-Goldstone bosons or moduli. This ultralight mode freezes on super-horizon scales and acts as a constant source for the curvature perturbation, making it grow linearly in time and effectively suppressingmore » the isocurvature component. We identify a Stückelberg-like emergent shift symmetry that underlies this behavior. As inflation lasts for many e -folds, the integrated effect of this source enhances the power spectrum of the adiabatic mode, while keeping the non-adiabatic spectrum approximately untouched. In this case, towards the end of inflation all the fluctuations, adiabatic and non-adiabatic, are dominated by a single degree of freedom.« less

Cumulative effects in inflation with ultra-light entropy modes

NASA Astrophysics Data System (ADS)

Achúcarro, Ana; Atal, Vicente; Germani, Cristiano; Palma, Gonzalo A.

2017-02-01

In multi-field inflation one or more non-adiabatic modes may become light, potentially inducing large levels of isocurvature perturbations in the cosmic microwave background. If in addition these light modes are coupled to the adiabatic mode, they influence its evolution on super horizon scales. Here we consider the case in which a non-adiabatic mode becomes approximately massless (``ultralight") while still coupled to the adiabatic mode, a typical situation that arises with pseudo-Nambu-Goldstone bosons or moduli. This ultralight mode freezes on super-horizon scales and acts as a constant source for the curvature perturbation, making it grow linearly in time and effectively suppressing the isocurvature component. We identify a Stückelberg-like emergent shift symmetry that underlies this behavior. As inflation lasts for many e-folds, the integrated effect of this source enhances the power spectrum of the adiabatic mode, while keeping the non-adiabatic spectrum approximately untouched. In this case, towards the end of inflation all the fluctuations, adiabatic and non-adiabatic, are dominated by a single degree of freedom.

75 FR 82414 - Carolina Power & Light Company; H. B. Robinson Steam Electric Plant, Unit No. 2; Exemption

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-30

... NUCLEAR REGULATORY COMMISSION [Docket No. 50-261; NRC-2010-0062] Carolina Power & Light Company; H. B. Robinson Steam Electric Plant, Unit No. 2; Exemption 1.0 Background Carolina Power & Light Company (CP&L, the licensee) is the holder of Renewed Facility Operating License No. DPR-23, which...

77 FR 26793 - Florida Power and Light Company, St. Lucie Plant, Unit No. 2, Exemption

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-07

... NUCLEAR REGULATORY COMMISSION [Docket No. 50-389; NRC-2011-0194] Florida Power and Light Company, St. Lucie Plant, Unit No. 2, Exemption 1.0 Background The Florida Power & Light Company (FPL, the licensee) is the holder of Renewed Facility Operating License No. NPF-16, which authorizes operation of St...

Trapping of Rift Valley Fever (RVF) vectors using Light Emitting Diode (LED) CDC traps in two arboviral disease hot spots in Kenya

USDA-ARS?s Scientific Manuscript database

Background: Mosquitoes’ response to artificial lights including color has been exploited in trap designs for improved sampling of mosquito vectors. Earlier studies suggest that mosquitoes are attracted to specific wavelengths of light and thus the need to refine techniques to increase mosquito captu...

The Imprint of the Extragalactic Background Light in the Gamma-Ray Spectra of Blazars

DOE PAGES

Ackermann, M.; Ajello, M.; Allafort, A.; ...

2012-11-30

The light emitted by stars and accreting compact objects through the history of the universe is encoded in the intensity of the extragalactic background light (EBL). Knowledge of the EBL is important to understand the nature of star formation and galaxy evolution, but direct measurements of the EBL are limited by galactic and other foreground emissions. In this paper, we report an absorption feature seen in the combined spectra of a sample of gamma-ray blazars out to a redshift of z ~ 1.6. Finally, this feature is caused by attenuation of gamma rays by the EBL at optical to ultravioletmore » frequencies and allowed us to measure the EBL flux density in this frequency band.« less

Evaluation of Light Collection System for Pion and Kaon Experiments in Hall C at Jefferson Lab

NASA Astrophysics Data System (ADS)

Roustom, Salim

2017-09-01

The neutral pion and the kaon are opportune to study the hadron structure through General Parton Distributions, which can be viewed as spatial densities at different momenta of the quarks inside the proton. To study hadron structure with pion or kaon experiments in Hall C at 12 GeV Jefferson Lab, one must analyze the final state neutral pions and kaons and their decay products. For the analysis of these particles, dedicated detectors based on the Cherenkov or scintillation mechanism are used, e.g. the HMS and SHMS aerogel detectors and the PbWO4-based Neutral Particle Spectrometer. A critical part of these detectors is the light collection system. Photomultiplier Tubes (PMTs) have many advantages, however, they are sensitive to magnetic fields and can get damaged by elevated helium levels in the atmosphere. An alternative to PMTs are Avalanche Photodiodes (APDs). APDs are sensitive to background noise, temperature, and radiation. It is thus important to evaluate the benefits of each light collection system and optimize operating conditions to ensure performance over a reasonably long time. I will present a performance study of PMTs exposed to elevated levels of helium and a comparison of APDs as alternatives, as well as new, compact readout methods. Supported in part by NSF Grants PHY-1714133, PHY-1530874, PHY-1306227 and PHY-1306418.

Elymus repens biomass allocation and acquisition as affected by light and nutrient supply and companion crop competition

PubMed Central

Ringselle, Björn; Prieto-Ruiz, Inés; Andersson, Lars; Aronsson, Helena; Bergkvist, Göran

2017-01-01

Background and Aims Competitive crops are a central component of resource-efficient weed control, especially for problematic perennial weeds such as Elymus repens. Competition not only reduces total weed biomass, but denial of resources can also change the allocation pattern – potentially away from the underground storage organs that make perennial weeds difficult to control. Thus, the competition mode of crops may be an important component in the design of resource-efficient cropping systems. Our aim was to determine how competition from companion crops with different modes of competition affect E. repens biomass acquisition and allocation and discuss that in relation to how E. repens responds to different levels of light and nutrient supply. Methods Greenhouse experiments were conducted with E. repens growing in interspecific competition with increasing density of perennial ryegrass or red clover, or growing at three levels of both light and nutrient supply. Key Results Elymus repens total biomass decreased with increasing biomass of the companion crop and the rate of decrease was higher with red clover than with perennial ryegrass, particularly for E. repens rhizome biomass. A reduced nutrient supply shifted E. repens allocation towards below-ground biomass while a reduced light supply shifted it towards shoot biomass. Red clover caused no change in E. repens allocation pattern, while ryegrass mostly shifted the allocation towards below-ground biomass, but the change was not correlated with ryegrass biomass. Conclusions The companion crop mode of competition influences both the suppression rate of E. repens biomass acquisition and the likelihood of shifts in E. repens biomass allocation. PMID:28025285

Best Map Ever of the Universe

NASA Image and Video Library

2013-03-21

This map shows the oldest light in our universe, as detected with the greatest precision yet by ESA Planck mission. The ancient light, called the cosmic microwave background, was imprinted on the sky when the universe was 370,000 years old.

The STIS CCD Spectroscopic Line Spread Functions

NASA Technical Reports Server (NTRS)

Gull, T.; Lindler, D.; Tennant, D.; Bowers, C.; Grady, C.; Hill, R. S.; Malumuth, E.

2002-01-01

We characterize the spectroscopic line spread functions of the spectroscopic CCD modes for high contrast objects. Our long range goal is to develop tools that accurately extract spectroscopic information of faint, point or extended sources in the vicinity of bright, point sources at separations approaching the realizable angular limits of HST with STIS. Diffracted and scattered light due to the HST optics, and scattered light effects within the STIS are addressed. Filter fringing, CCD fringing, window reflections, and scattering within the detector and other effects are noted. We have obtained spectra of several reference stars, used for flux calibration or for coronagraphic standards, that have spectral distributions ranging from very red to very blue. Spectra of each star were recorded with the star in the aperture and with the star blocked by either the F1 or F2 fiducial. Plots of the detected starlight along the spatial axis of the aperture are provided for four stars. With the star in the aperture, the line spread function is quite noticeable. Placing the star behind one of the fiducials cuts the scattered light and the diffracted light, is detectable even out to 1OOOOA. When the star is placed behind either fiducial, the scattered and diffracted light components, at three arcseconds displacement from the star, are below lop6 the peak of the star at wavelengths below 6000A; at the same angular distance, scattered light does contaminate the background longward of 6000A up to a level of 10(exp -5).

Search for neutrinoless double beta decay with GERDA phase II

NASA Astrophysics Data System (ADS)

Agostini, M.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Baudis, L.; Bauer, C.; Bellotti, E.; Belogurov, S.; Bettini, A.; Bezrukov, L.; Bode, T.; Borowicz, D.; Brudanin, V.; Brugnera, R.; Caldwell, A.; Cattadori, C.; Chernogorov, A.; D'Andrea, V.; Demidova, E. V.; Di Marco, N.; Domula, A.; Doroshkevich, E.; Egorov, V.; Falkenstein, R.; Gangapshev, A.; Garfagnini, A.; Gooch, C.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Hakenmüller, J.; Hegai, A.; Heisel, M.; Hemmer, S.; Hofmann, W.; Hult, M.; Inzhechik, L. V.; Csáthy, J. Janicskó; Jochum, J.; Junker, M.; Kazalov, V.; Kihm, T.; Kirpichnikov, I. V.; Kirsch, A.; Kish, A.; Klimenko, A.; Kneißl, R.; Knies, J.; Knöpfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kuzminov, V. V.; Laubenstein, M.; Lazzaro, A.; Lebedev, V. I.; Liao, H. Y.; Lindner, M.; Lippi, I.; Lubashevskiy, A.; Lubsandorzhiev, B.; Lutter, G.; Majorovits, B.; Maneschg, W.; Marissens, G.; Miloradovic, M.; Mingazheva, R.; Misiaszek, M.; Moseev, P.; Nemchenok, I.; Panas, K.; Pandola, L.; Pelczar, K.; Pullia, A.; Ransom, C.; Reissfelder, M.; Riboldi, S.; Rumyantseva, N.; Sada, C.; Salamida, F.; Schmitt, C.; Schneider, B.; Schönert, S.; Schreiner, J.; Schulz, O.; Schütz, A.-K.; Schwingenheuer, B.; Seitz, H.; Selivanenko, O.; Shevchik, E.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Vanhoefer, L.; Vasenko, A. A.; Veresnikova, A.; von Sturm, K.; Wagner, V.; Wegmann, A.; Wester, T.; Wiesinger, C.; Wojcik, M.; Yanovich, E.; Zhitnikov, I.; Zhukov, S. V.; Zinatulina, D.; Zuber, K.; Zuzel, G.

2017-10-01

The GERmanium Detector Array (gerda) experiment, located at the Gran Sasso underground laboratory in Italy, is one of the leading experiments for the search of 0νββ decay. In Phase II of the experiment 35.6 kg of enriched germanium detectors are operated. The application of active background rejection methods, such as a liquid argon scintillation light read-out and pulse shape discrimination of germanium detector signals, allowed to reduce the background index to the intended level of 10-3 cts/(keV.kg.yr). In the first five month of data taking 10.8 kg yr of exposure were accumulated. No signal has been found and together with data from Phase I a new limit for the neutrinoless double beta decay half-life of 76Ge of 5.3 . 1025 yr at 90% C.L. was established in June 2016. Phase II data taking is ongoing and will allow the exploration of half-lifes in the 1026 yr regime. The current status of data taking and an update on the background index are presented.

Measurement of suspended solids in lakes and oceans using satellite remote sensing data

NASA Technical Reports Server (NTRS)

Sydor, M. (Principal Investigator)

1980-01-01

Using satellite remote sensing data to measure low concentrations of suspended solids in lakes and oceans requires careful evaluation of background signals from the atmosphere and the water surface. Typical background corrections for Lake Superior are presented and the spectral distribution of the residual radiance from three major categories of turbidity in the lake are determined. The results indicate that for large bodies of water, some general information on atmospheric scattering, water clarity, and the optical properties of suspended solids allows estimates of concentrations of suspended solids to within + or - 0.5 mg/L without using real time ground truth data. Under calibrated conditions the threshold detection level is 0.3 mg/L for the fine particulates dispersed throughout the lake and 1 mg/L for the highly light absorbing effluent from rivers. Comparisons of the minimum reflectance over the open lake areas with reflection from the highly absorbing tannin water from rivers provides a check on the clarity of the atmosphere and the excessive background scatter from the water surface.

Production, fixation, and staining of cells on slides for maximum photometric sensitivity

NASA Astrophysics Data System (ADS)

Leif, Robert C.; Harlow, Patrick M.; Vallarino, Lidia M.

1994-07-01

The need to detect increasingly low levels of antigens or polynucleotides in cells requires improvements in both the preparation and the staining of samples. The combination of centrifugal cytology with the use of glyoxal as cross-linking fixative produces monolayers of cells having minimum background fluorescence. Detection can be further improved by the use of a recently developed type of luminescent tag containing a lanthanide(III) ion as the light- emitting center. These novel tags are macrocyclic complexes functionalized with an isothiocyanate group to allow covalent coupling to a biosubstrate. The Eu(III) complex possesses a set of properties -- water solubility, inertness to metal release over a wide pH range, ligand-sensitized narrow-band luminescence, large Stoke's shift, and long excited-state lifetime -- that provides ease of staining as well as maximum signal with minimum interference from background autofluorescence. Luminescence efficiency studies indicate significant solvent effects.

A guideline to medical photography: a perspective on digital photography in an orthopaedic setting.

PubMed

de Meijer, P P G; Karlsson, J; LaPrade, R F; Verhaar, J A N; Wijdicks, C A

2012-12-01

Quality photographs are essential for clinical documentation, research, and publication in scientific journals and teaching. Oftentimes, non-ideal lighting and a sterile environment restrict the medical photographer, resulting in lower-quality photographs. This article aims to provide a clear and comprehensible guideline for medical photography in an orthopaedic setting. This article is based on extensive photographic involvement in operating and laboratory settings, in close collaboration with medical professionals from the Steadman Clinic (Vail, Colorado, USA), Gothenburg University (Göteborg, Sweden) and Erasmus MC (Rotterdam, the Netherlands). Background literature was searched through Google Scholar and PubMed. Three relevant journal articles, and one book on medical photography, were used to write this paper. Seventeen Internet articles were used for background information. A relevant, up-to-date and comprehensive guideline to medical photography for medical professionals, with or without photographic experience, is provided. Expert opinion, Level V.

Climbing plants in a temperate rainforest understorey: searching for high light or coping with deep shade?

PubMed Central

Valladares, Fernando; Gianoli, Ernesto; Saldaña, Alfredo

2011-01-01

Background and Aims While the climbing habit allows vines to reach well-lit canopy areas with a minimum investment in support biomass, many of them have to survive under the dim understorey light during certain stages of their life cycle. But, if the growth/survival trade-off widely reported for trees hold for climbing plants, they cannot maximize both light-interception efficiency and shade avoidance (i.e. escaping from the understorey). The seven most important woody climbers occurring in a Chilean temperate evergreen rainforest were studied with the hypothesis that light-capture efficiency of climbers would be positively associated with their abundance in the understorey. Methods Species abundance in the understorey was quantified from their relative frequency and density in field plots, the light environment was quantified by hemispherical photography, the photosynthetic response to light was measured with portable gas-exchange analyser, and the whole shoot light-interception efficiency and carbon gain was estimated with the 3-D computer model Y-plant. Key Results Species differed in specific leaf area, leaf mass fraction, above ground leaf area ratio, light-interception efficiency and potential carbon gain. Abundance of species in the understorey was related to whole shoot features but not to leaf level features such as specific leaf area. Potential carbon gain was inversely related to light-interception efficiency. Mutual shading among leaves within a shoot was very low (<20 %). Conclusions The abundance of climbing plants in this southern rainforest understorey was directly related to their capacity to intercept light efficiently but not to their potential carbon gain. The most abundant climbers in this ecosystem match well with a shade-tolerance syndrome in contrast to the pioneer-like nature of climbers observed in tropical studies. The climbers studied seem to sacrifice high-light searching for coping with the dim understorey light. PMID:21685433

Late time neutrino masses, the LSND experiment, and the cosmic microwave background.

PubMed

Chacko, Z; Hall, Lawrence J; Oliver, Steven J; Perelstein, Maxim

2005-03-25

Models with low-scale breaking of global symmetries in the neutrino sector provide an alternative to the seesaw mechanism for understanding why neutrinos are light. Such models can easily incorporate light sterile neutrinos required by the Liquid Scintillator Neutrino Detector experiment. Furthermore, the constraints on the sterile neutrino properties from nucleosynthesis and large-scale structure can be removed due to the nonconventional cosmological evolution of neutrino masses and densities. We present explicit, fully realistic supersymmetric models, and discuss the characteristic signatures predicted in the angular distributions of the cosmic microwave background.

Bessel light sheet structured illumination microscopy

NASA Astrophysics Data System (ADS)

Noshirvani Allahabadi, Golchehr

Biomedical study researchers using animals to model disease and treatment need fast, deep, noninvasive, and inexpensive multi-channel imaging methods. Traditional fluorescence microscopy meets those criteria to an extent. Specifically, two-photon and confocal microscopy, the two most commonly used methods, are limited in penetration depth, cost, resolution, and field of view. In addition, two-photon microscopy has limited ability in multi-channel imaging. Light sheet microscopy, a fast developing 3D fluorescence imaging method, offers attractive advantages over traditional two-photon and confocal microscopy. Light sheet microscopy is much more applicable for in vivo 3D time-lapsed imaging, owing to its selective illumination of tissue layer, superior speed, low light exposure, high penetration depth, and low levels of photobleaching. However, standard light sheet microscopy using Gaussian beam excitation has two main disadvantages: 1) the field of view (FOV) of light sheet microscopy is limited by the depth of focus of the Gaussian beam. 2) Light-sheet images can be degraded by scattering, which limits the penetration of the excitation beam and blurs emission images in deep tissue layers. While two-sided sheet illumination, which doubles the field of view by illuminating the sample from opposite sides, offers a potential solution, the technique adds complexity and cost to the imaging system. We investigate a new technique to address these limitations: Bessel light sheet microscopy in combination with incoherent nonlinear Structured Illumination Microscopy (SIM). Results demonstrate that, at visible wavelengths, Bessel excitation penetrates up to 250 microns deep in the scattering media with single-side illumination. Bessel light sheet microscope achieves confocal level resolution at a lateral resolution of 0.3 micron and an axial resolution of 1 micron. Incoherent nonlinear SIM further reduces the diffused background in Bessel light sheet images, resulting in confocal quality images in thick tissue. The technique was applied to live transgenic zebra fish tg(kdrl:GFP), and the sub-cellular structure of fish vasculature genetically labeled with GFP was captured in 3D. The superior speed of the microscope enables us to acquire signal from 200 layers of a thick sample in 4 minutes. The compact microscope uses exclusively off-the-shelf components and offers a low-cost imaging solution for studying small animal models or tissue samples.

First Stars or Stray Stars? A Cosmic Infrared Mystery

NASA Image and Video Library

2014-11-06

Our sky is filled with a diffuse background glow, known as the cosmic infrared background. Much of the light is from galaxies we know about, but previous Spitzer measurements have shown an extra component of unknown origin.

Can combined use of low-level lasers and hyaluronic acid injections prolong the longevity of degenerative knee joints?

PubMed Central

Ip, David; Fu, Nga Yue

2015-01-01

Background This study evaluated whether half-yearly hyaluronic acid injection together with low-level laser therapy in addition to standard conventional physical therapy can successfully postpone the need for joint replacement surgery in elderly patients with bilateral symptomatic tricompartmental knee arthritis. Methods In this prospective, double-blind, placebo-controlled study, 70 consecutive unselected elderly patients with bilateral tricompartmental knee arthritis were assigned at random to either one of two conservative treatment protocols to either one of the painful knees. Protocol A consisted of conventional physical therapy plus a sham light source plus saline injection, and protocol B consisted of protocol A with addition of half-yearly hyaluronic acid injection as well as low-level laser treatment instead of using saline and a sham light source. Treatment failure was defined as breakthrough pain necessitating joint replacement. Results Among the 140 painful knees treated with either protocol A or protocol B, only one of the 70 painful knees treated by protocol B required joint replacement, whereas 15 of the 70 painful knees treated by protocol A needed joint replacement surgery (P<0.05). Conclusion We conclude that half-yearly hyaluronic acid injections together with low-level laser therapy should be incorporated into the standard conservative treatment protocol for symptomatic knee arthritis, because it may prolong the longevity of the knee joint without the need for joint replacement. PMID:26346122

Shear bond strength of orthodontic color-change adhesives with different light-curing times

PubMed Central

Bayani, Shahin; Ghassemi, Amirreza; Manafi, Safa; Delavarian, Mohadeseh

2015-01-01

Background: The purpose of this study was to evaluate the effect of light-curing time on the shear bond strength (SBS) of two orthodontic color-change adhesives (CCAs). Materials and Methods: A total of 72 extracted premolars were randomly assigned into 6 groups of 12 teeth each. Subsequent to primer application, a metal bracket was bonded to the buccal surface using an orthodontic adhesive. Two CCAs (Greengloo and Transbond Plus) were tested and one conventional light-cured adhesive (Resilience) served as control. For each adhesive, the specimens were light-cured for two different times of 20 and 40 s. All the specimens underwent mechanical testing using a universal testing machine to measure the SBS. Adhesive remnant index (ARI) was used to assess the remnant adhesive material on the tooth surface. All statistical analyses were performed using SPSS software. The significance level for all statistical tests was set at P ≤ 0.05. Results: The SBSs of the tested groups were in the range of 14.05-31.25 MPa. Greengloo adhesive showed the highest SBS values when light-cured for 40 s, and Transbond Plus adhesive showed the lowest values when light-cured for 20 s. ARI scores of Transbond Plus adhesive were significantly higher than those of controls, while other differences in ARI values were not significant. Conclusion: Within the limitations of his study, decreasing the light-curing time from 40 to 20 s decreased the SBS of the tested adhesives; however, this decline in SBS was statistically significant only in Transbond Plus adhesive PMID:26005468

Investigating the applicability of activity-based quantum mechanics in a few high school physics classrooms

NASA Astrophysics Data System (ADS)

Escalada, Lawrence Todd

Quantum physics is not traditionally introduced in high school physics courses because of the level of abstraction and mathematical formalism associated with the subject. As part of the Visual Quantum Mechanics project, activity-based instructional units have been developed that introduce quantum principles to students who have limited backgrounds in physics and mathematics. This study investigates the applicability of one unit, Solids & Light, that introduces quantum principles within the context of learning about light emitting diodes. An observation protocol, attitude surveys, and questionnaires were used to examine the implementation of materials and student-teacher interactions in various secondary physics classrooms. Aspects of Solids & Light including the use of hands-on activities, interactive computer programs, inexpensive materials, and the focus on conceptual understanding were very applicable in the various physics classrooms observed. Both teachers and students gave these instructional strategies favorable ratings in motivating students to make observations and to learn. These ratings were not significantly affected by gender or students, attitudes towards physics or computers. Solid's & Light was applicable in terms of content and teaching style for some teachers. However, a mismatch of teaching styles between some instructors and the unit posed some problems in determining applicability. Observations indicated that some instructors were not able to utilize the exploratory instructional strategy of Solid's & Light. Thus, Solids & Light must include additional support necessary to make the instructor comfortable with the subject matter and pedagogical style. With these revisions, Solids & Light, will have all the key components to make its implementation in a high school physics classroom a successful one.

Single photon detection imaging of Cherenkov light emitted during radiation therapy

NASA Astrophysics Data System (ADS)

Adamson, Philip M.; Andreozzi, Jacqueline M.; LaRochelle, Ethan; Gladstone, David J.; Pogue, Brian W.

2018-03-01

Cherenkov imaging during radiation therapy has been developed as a tool for dosimetry, which could have applications in patient delivery verification or in regular quality audit. The cameras used are intensified imaging sensors, either ICCD or ICMOS cameras, which allow important features of imaging, including: (1) nanosecond time gating, (2) amplification by 103-104, which together allow for imaging which has (1) real time capture at 10-30 frames per second, (2) sensitivity at the level of single photon event level, and (3) ability to suppress background light from the ambient room. However, the capability to achieve single photon imaging has not been fully analyzed to date, and as such was the focus of this study. The ability to quantitatively characterize how a single photon event appears in amplified camera imaging from the Cherenkov images was analyzed with image processing. The signal seen at normal gain levels appears to be a blur of about 90 counts in the CCD detector, after going through the chain of photocathode detection, amplification through a microchannel plate PMT, excitation onto a phosphor screen and then imaged on the CCD. The analysis of single photon events requires careful interpretation of the fixed pattern noise, statistical quantum noise distributions, and the spatial spread of each pulse through the ICCD.

Model analysis for the MAGIC telescope

NASA Astrophysics Data System (ADS)

Mazin, D.; Bigongiari, C.; Goebel, F.; Moralejo, A.; Wittek, W.

The MAGIC Collaboration operates the 17m imaging Cherenkov telescope on the Canary island La Palma. The main goal of the experiment is an energy threshold below 100 GeV for primary gamma rays. The new analysis technique (model analysis) takes advantage of the high resolution (both in space and time) camera by fitting the averaged expected templates of the shower development to the measured shower images in the camera. This approach allows to recognize and reconstruct images just above the level of the night sky background light fluctuations. Progress and preliminary results of the model analysis technique will be presented.

Evaluating optical hazards from plasma arc cutting.

PubMed

Glassford, Eric; Burr, Gregory

2018-01-01

The Health Hazard Evaluation Program of the National Institute for Occupational Safety and Health evaluated a steel building materials manufacturer. The employer requested the evaluation because of concerns about optical radiation hazards from a plasma arc cutting system and the need to clarify eye protection requirements for plasma operators, other employees, and visitors. The strength of the ultraviolet radiation, visible radiation (light), and infrared radiation generated by the plasma arc cutter was measured at various distances from the source and at different operating amperages. Investigators also observed employees performing the plasma arc cutting. Optical radiation above safe levels for the unprotected eyes in the ultraviolet-C, ultraviolet-B, and visible light ranges were found during plasma arc cutting. In contrast, infrared and ultraviolet-A radiation levels during plasma arc cutting were similar to background levels. The highest non-ionizing radiation exposures occurred when no welding curtains were used. A plasma arc welding curtain in place did not eliminate optical radiation hazards to the plasma arc operator or to nearby employees. In most instances, the measured intensities for visible light, UV-C, and UV-B resulted in welding shade lens numbers that were lower than those stipulated in the OSHA Filter Lenses for Protection Against Radiant Energy table in 29 CFR 1910.133(a)(5). [1] Investigators recommended using a welding curtain that enclosed the plasma arc, posting optical radiation warning signs in the plasma arc cutter area, installing audible or visual warning cues when the plasma arc cutter was operating, and using welding shades that covered the plasma arc cutter operator's face to protect skin from ultraviolet radiation hazards.

Low-Level Light Therapy Potentiates NPe6-mediated Photodynamic Therapy in a Human Osteosarcoma Cell Line via Increased ATP

PubMed Central

Tsai, Shang-Ru; Yin, Rui; Huang, Ying-Ying; Sheu, Bor-Ching; Lee, Si-Chen; Hamblin, Michael R.

2015-01-01

Background Low-Level Light Therapy (LLLT) is used to stimulate healing, reduce pain and inflammation, and preserve tissue from dying. LLLT has been shown to protect cells in culture from dying after various cytotoxic insults, and LLLT is known to increase the cellular ATP content. Previous studies have demonstrated that maintaining a sufficiently high ATP level is necessary for the efficient induction and execution of apoptosis steps after photodynamic therapy (PDT). Methods We asked whether LLLT would protect cells from cytotoxicity due to PDT, or conversely whether LLLT would enhance the efficacy of PDT mediated by mono-L-aspartyl chlorin(e6) (NPe6). Increased ATP could lead to enhanced cell uptake of NPe6 by the energy dependent process of endocytosis, and also to more efficient apoptosis. In this study, human osteosarcoma cell line MG-63 was subjected to 1.5 J/cm2 of 810 nm near infrared radiation (NIR) followed by addition of 10 μM NPe6 and after 2 h incubation by 1.5 J/cm2 of 652 nm red light for PDT. Results PDT combined with LLLT led to higher cell death and increased intracellular reactive oxygen species compared to PDT alone. The uptake of NPe6 was moderately increased by LLLT, and cellular ATP was increased. The mitochondrial respiratory chain inhibitor antimycin A abrogated the LLLT-induced increase in cytotoxicity. Conclusions Taken together, these results demonstrate that LLLT potentiates NPe6-mediated PDT via increased ATP synthesis and is a potentially promising strategy that could be applied in clinical PDT. PMID:25462575

Light-Toned Bedrock Along Cracks as Evidence of Fluid Alteration

NASA Image and Video Library

2007-02-15

This enhanced-color image from the HiRISE camera on NASA Mars Reconnaissance Orbiter shows a landscape of sand dunes and buttes among a background of light-toned bands and dark-toned bands in the Candor Chasma region

LED light design method for high contrast and uniform illumination imaging in machine vision.

PubMed

Wu, Xiaojun; Gao, Guangming

2018-03-01

In machine vision, illumination is very critical to determine the complexity of the inspection algorithms. Proper lights can obtain clear and sharp images with the highest contrast and low noise between the interested object and the background, which is conducive to the target being located, measured, or inspected. Contrary to the empirically based trial-and-error convention to select the off-the-shelf LED light in machine vision, an optimization algorithm for LED light design is proposed in this paper. It is composed of the contrast optimization modeling and the uniform illumination technology for non-normal incidence (UINI). The contrast optimization model is built based on the surface reflection characteristics, e.g., the roughness, the reflective index, and light direction, etc., to maximize the contrast between the features of interest and the background. The UINI can keep the uniformity of the optimized lighting by the contrast optimization model. The simulation and experimental results demonstrate that the optimization algorithm is effective and suitable to produce images with the highest contrast and uniformity, which is very inspirational to the design of LED illumination systems in machine vision.

Evidence for light-by-light scattering in heavy-ion collisions with the ATLAS detector at the LHC

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

Aaboud, M.; Aad, G.; Abbott, B.

Light-by-light scattering (γγ → γγ) is a quantum-mechanical process that is forbidden in the classical theory of electrodynamics. This reaction is accessible at the Large Hadron Collider thanks to the large electromagnetic field strengths generated by ultra-relativistic colliding lead ions. Using 480 μb -1 of lead–lead collision data recorded at a centre-of-mass energy per nucleon pair of 5.02 TeV by the ATLAS detector, here we report evidence for light-by-light scattering. A total of 13 candidate events were observed with an expected background of 2.6 ± 0.7 events. After background subtraction and analysis corrections, the fiducial cross-section of the process Pbmore » + Pb (γγ) → Pb(*) + Pb(*)γγ, for photon transverse energy E T > 3 GeV, photon absolute pseudorapidity |η| < 2.4, diphoton invariant mass greater than 6 GeV, diphoton transverse momentum lower than 2 GeV and diphoton acoplanarity below 0.01, is measured to be 70 ± 24 (stat.) ± 17 (syst.) nb, which is in agreement with the standard model predictions.« less

Evidence for light-by-light scattering in heavy-ion collisions with the ATLAS detector at the LHC

DOE PAGES

Aaboud, M.; Aad, G.; Abbott, B.; ...

2017-08-14

Light-by-light scattering (γγ → γγ) is a quantum-mechanical process that is forbidden in the classical theory of electrodynamics. This reaction is accessible at the Large Hadron Collider thanks to the large electromagnetic field strengths generated by ultra-relativistic colliding lead ions. Using 480 μb -1 of lead–lead collision data recorded at a centre-of-mass energy per nucleon pair of 5.02 TeV by the ATLAS detector, here we report evidence for light-by-light scattering. A total of 13 candidate events were observed with an expected background of 2.6 ± 0.7 events. After background subtraction and analysis corrections, the fiducial cross-section of the process Pbmore » + Pb (γγ) → Pb(*) + Pb(*)γγ, for photon transverse energy E T > 3 GeV, photon absolute pseudorapidity |η| < 2.4, diphoton invariant mass greater than 6 GeV, diphoton transverse momentum lower than 2 GeV and diphoton acoplanarity below 0.01, is measured to be 70 ± 24 (stat.) ± 17 (syst.) nb, which is in agreement with the standard model predictions.« less

Rejection of randomly coinciding events in ZnMoO scintillating bolometers

NASA Astrophysics Data System (ADS)

Chernyak, D. M.; Danevich, F. A.; Giuliani, A.; Mancuso, M.; Nones, C.; Olivieri, E.; Tenconi, M.; Tretyak, V. I.

2014-06-01

Random coincidence of events (particularly from two neutrino double beta decay) could be one of the main sources of background in the search for neutrinoless double beta decay with cryogenic bolometers due to their poor time resolution. Pulse-shape discrimination by using front edge analysis, mean-time and methods were applied to discriminate randomly coinciding events in ZnMoO cryogenic scintillating bolometers. These events can be effectively rejected at the level of 99 % by the analysis of the heat signals with rise-time of about 14 ms and signal-to-noise ratio of 900, and at the level of 92 % by the analysis of the light signals with rise-time of about 3 ms and signal-to-noise ratio of 30, under the requirement to detect 95 % of single events. These rejection efficiencies are compatible with extremely low background levels in the region of interest of neutrinoless double beta decay of Mo for enriched ZnMoO detectors, of the order of counts/(y keV kg). Pulse-shape parameters have been chosen on the basis of the performance of a real massive ZnMoO scintillating bolometer. Importance of the signal-to-noise ratio, correct finding of the signal start and choice of an appropriate sampling frequency are discussed.

Tokamak-independent software analysis suite for multi-spectral line-polarization MSE diagnostics

DOE PAGES

Scott, S. D.; Mumgaard, R. T.

2016-07-20

A tokamak-independent analysis suite has been developed to process data from Motional Stark Effect (mse) diagnostics. The software supports multi-spectral line-polarization mse diagnostics which simultaneously measure emission at the mse σ and π lines as well as at two "background" wavelengths that are displaced from the mse spectrum by a few nanometers. This analysis accurately estimates the amplitude of partially polarized background light at the σ and π wavelengths even in situations where the background light changes rapidly in time and space, a distinct improvement over traditional "time-interpolation" background estimation. The signal amplitude at many frequencies is computed using amore » numerical-beat algorithm which allows the retardance of the mse photo-elastic modulators (pem's) to be monitored during routine operation. It also allows the use of summed intensities at multiple frequencies in the calculation of polarization direction, which increases the effective signal strength and reduces sensitivity to pem retardance drift. The software allows the polarization angles to be corrected for calibration drift using a system that illuminates the mse diagnostic with polarized light at four known polarization angles within ten seconds of a plasma discharge. As a result, the software suite is modular, parallelized, and portable to other facilities.« less

Tokamak-independent software analysis suite for multi-spectral line-polarization MSE diagnostics

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

Scott, S. D.; Mumgaard, R. T.

A tokamak-independent analysis suite has been developed to process data from Motional Stark Effect (mse) diagnostics. The software supports multi-spectral line-polarization mse diagnostics which simultaneously measure emission at the mse σ and π lines as well as at two "background" wavelengths that are displaced from the mse spectrum by a few nanometers. This analysis accurately estimates the amplitude of partially polarized background light at the σ and π wavelengths even in situations where the background light changes rapidly in time and space, a distinct improvement over traditional "time-interpolation" background estimation. The signal amplitude at many frequencies is computed using amore » numerical-beat algorithm which allows the retardance of the mse photo-elastic modulators (pem's) to be monitored during routine operation. It also allows the use of summed intensities at multiple frequencies in the calculation of polarization direction, which increases the effective signal strength and reduces sensitivity to pem retardance drift. The software allows the polarization angles to be corrected for calibration drift using a system that illuminates the mse diagnostic with polarized light at four known polarization angles within ten seconds of a plasma discharge. As a result, the software suite is modular, parallelized, and portable to other facilities.« less

Effect of timed bright light treatment for rest-activity disruption in institutionalized patients with Alzheimer’s disease

PubMed Central

Dowling, Glenna A.; Mastick, Judy; Hubbard, Erin M.; Luxenberg, Jay S.; Burr, Robert L.

2008-01-01

SUMMARY Background Disturbances in rest-activity rhythm are prominent and disabling symptoms in Alzheimer’s disease (AD). Nighttime sleep is severely fragmented and daytime activity is disrupted by multiple napping episodes. In most institutional environments, light levels are very low and may not be sufficient to entrain the circadian clock to the 24-hour day. Method The purpose of this randomized clinical trial was to test the effectiveness of timed bright light therapy in reducing rest-activity (circadian) disruption in institutionalized patients with AD. The experimental groups received either morning (9.30–10.30 am) or afternoon (3.30–4.30 pm) bright light exposure (≥ 2500 lux in gaze direction) Monday through Friday for 10 weeks. The control group received usual indoor light (150–200 lux). Nighttime sleep, daytime wake, and rest-activity parameters were determined by actigraphy. Repeated measures analysis of variance was employed to test the primary study hypotheses. Results Seventy institutionalized subjects with AD (mean age 84) completed the study. No significant differences in actigraphy-based measures of nighttime sleep or daytime wake were found between groups. Subjects in either experimental light condition evidenced a significantly (p < 0.01) more stable rest-activity rhythm acrophase over the 10-week treatment period compared to the control subjects whose rhythm phase delayed by over two hours. Conclusions One hour of bright light, administered to subjects with AD either in the morning or afternoon, did not improve nighttime sleep or daytime wake compared to a control group of similar subjects. However, exposure to one-hour of bright light in either the morning or afternoon may provide sufficient additional input to the circadian pacemaker to facilitate entrainment to the 24-hour day. PMID:16035127

A polarization measurement method for the quantification of retardation in optic nerve fiber layer

NASA Astrophysics Data System (ADS)

Fukuma, Yasufumi; Okazaki, Yoshio; Shioiri, Takashi; Iida, Yukio; Kikuta, Hisao; Ohnuma, Kazuhiko

2008-02-01

The thickness measurement of the optic nerve fiber layer is one of the most important evaluations for carrying out glaucoma diagnosis. Because the optic nerve fiber layer has birefringence, the thickness can be measured by illuminating eye optics with circular polarized light and analyzing the elliptical rate of the detected polarized light reflected from the optic nerve fiber layer. In this method, the scattering light from the background and the retardation caused by the cornea disturbs the precise measurement. If the Stokes vector expressing the whole state of polarization can be detected, we can eliminate numerically the influence of the background scattering and of the retardation caused by the cornea. Because the retardation process of the eye optics can be represented by a numerical equation using the retardation matrix of each component and also the nonpolarized background scattering light, it can be calculated by using the Stokes vector. We applied a polarization analysis system that can detect the Stokes vector onto the fundus camera. The polarization analysis system is constructed with a CCD area image sensor, a linear polarizing plate, a micro phase plate array, and a circularly polarized light illumination unit. With this simply constructed system, we can calculate the retardation caused only by the optic nerve fiber layer and it can predict the thickness of the optic nerve fiber layer. We report the method and the results graphically showing the retardation of the optic nerve fiber layer without the retardation of the cornea.

Regulation of plant cell wall degradation by light in Trichoderma.

PubMed

Schmoll, Monika

2018-01-01

Trichoderma reesei (syn. Hypocrea jecorina ) is the model organism for industrial production of plant cell wall degradating enzymes. The integration of light and nutrient signals for adaptation of enzyme production in T. reesei emerged as an important regulatory mechanism to be tackled for strain improvement. Gene regulation specific for cellulase inducing conditions is different in light and darkness with substantial regulation by photoreceptors. Genes regulated by light are clustered in the genome, with several of the clusters overlapping with CAZyme clusters. Major cellulase transcription factor genes and at least 75% of glycoside hydrolase encoding genes show the potential of light dependent regulation. Accordingly, light dependent protein complex formation occurs within the promoters of cellulases and their regulators. Additionally growth on diverse carbon sources is different between light and darkness and dependent on the presence of photoreceptors in several cases. Thereby, also light intensity plays a regulatory role, with cellulase levels dropping at higher light intensities dependent in the strain background. The heterotrimeric G-protein pathway is the most important nutrient signaling pathway in the connection with light response and triggers posttranscriptional regulation of cellulase expression. All G-protein alpha subunits impact cellulase regulation in a light dependent manner. The downstream cAMP pathway is involved in light dependent regulation as well. Connections between the regulatory pathways are mainly established via the photoreceptor ENV1. The effect of photoreceptors on plant cell wall degradation also occurs in the model filamentous fungus Neurospora crassa . In the currently proposed model, T. reesei senses the presence of plant biomass in its environment by detection of building blocks of cellulose and hemicellulose. Interpretation of the respective signals is subsequently adjusted to the requirements in light and darkness (or on the surface versus within the substrate) by an interconnection of nutrient signaling with light response. This review provides an overview on the importance of light, photoreceptors and related signaling pathways for formation of plant cell wall degrading enzymes in T. reesei . Additionally, the relevance of light dependent gene regulation for industrial fermentations with Trichoderma as well as strategies for exploitation of the observed effects are discussed.

Light-sheet Bayesian microscopy enables deep-cell super-resolution imaging of heterochromatin in live human embryonic stem cells

PubMed Central

Hu, Ying S; Zhu, Quan; Elkins, Keri; Tse, Kevin; Li, Yu; Fitzpatrick, James A J; Verma, Inder M; Cang, Hu

2016-01-01

Background Heterochromatin in the nucleus of human embryonic cells plays an important role in the epigenetic regulation of gene expression. The architecture of heterochromatin and its dynamic organization remain elusive because of the lack of fast and high-resolution deep-cell imaging tools. We enable this task by advancing instrumental and algorithmic implementation of the localization-based super-resolution technique. Results We present light-sheet Bayesian super-resolution microscopy (LSBM). We adapt light-sheet illumination for super-resolution imaging by using a novel prism-coupled condenser design to illuminate a thin slice of the nucleus with high signal-to-noise ratio. Coupled with a Bayesian algorithm that resolves overlapping fluorophores from high-density areas, we show, for the first time, nanoscopic features of the heterochromatin structure in both fixed and live human embryonic stem cells. The enhanced temporal resolution allows capturing the dynamic change of heterochromatin with a lateral resolution of 50–60 nm on a time scale of 2.3 s. Conclusion Light-sheet Bayesian microscopy opens up broad new possibilities of probing nanometer-scale nuclear structures and real-time sub-cellular processes and other previously difficult-to-access intracellular regions of living cells at the single-molecule, and single cell level. PMID:27795878

Measurements of incoherent light and background structure at exo-Earth detection levels in the High Contrast Imaging Testbed

NASA Astrophysics Data System (ADS)

Cady, Eric; Shaklan, Stuart

2014-08-01

A major component of the estimation and correction of starlight at very high contrasts is the creation of a dark hole: a region in the vicinity of the core of the stellar point spread function (PSF) where speckles in the PSF wings have been greatly attenuated, up to a factor of 1010 for the imaging of terrestrial exoplanets. At these very high contrasts, removing these speckles requires distinguishing between light from the stellar PSF scattered by instrument imperfections, which may be partially corrected across a broad band using deformable mirrors in the system, from light from other sources which generally may not. These other sources may be external or internal to the instrument (e.g. planets, exozodiacal light), but in either case, their distinguishing characteristic is their inability to interfere coherently with the PSF. In the following we discuss the estimation, structure, and expected origin of this incoherent" signal, primarily in the context of a series of experiments made with a linear band-limited mask in Jan-Mar 2013. We find that the incoherent" signal at moderate contrasts is largely estimation error of the coherent signal, while at very high contrasts it represents a true floor which is stable over week-timescales.

Development of a 1 x N Fiber Optic Sensor Array for Carbon Sequestration Site Monitoring

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

Repasky, Kevin

2014-02-01

A fiber sensor array for sub-surface CO 2 concentrations measurements was developed for monitoring geologic carbon sequestration sites. The fiber sensor array uses a single temperature tunable distributed feedback (DFB) laser operating with a nominal wavelength of 2.004 μm. Light from this DFB laser is direct to one of the 4 probes via an in-line 1 x 4 fiber optic switch. Each of the 4 probes are buried and allow the sub-surface CO 2 to enter the probe through Millipore filters that allow the soil gas to enter the probe but keeps out the soil and water. Light from themore » DFB laser interacts with the CO 2 before it is directed back through the in-line fiber optic switch. The DFB laser is tuned across two CO 2 absorption features where a transmission measurement is made allowing the CO 2 concentration to be retrieved. The fiber optic switch then directs the light to the next probe where this process is repeated allowing sub-surface CO 2 concentration measurements at each of the probes to be made as a function of time. The fiber sensor array was deployed for fifty-eight days beginning June 19, 2012 at the Zero Emission Research Technology (ZERT) field site where sub-surface CO 2 concentrations were monitored. Background measurements indicate the fiber sensor array can monitor background levels as low as 1,000 parts per million (ppm). A thirty four day sub-surface release of 0.15 tones CO 2/day began on July 10, 2012. The elevated subsurface CO 2 concentration was easily detected by each of the four probes with values ranging to over 60,000 ppm, a factor of greater than 6 higher than background measurements. The fiber sensor array was also deploy at the Big Sky Carbon Sequestration Partnership (BSCSP) site in north-central Montana between July 9th and August 7th, 2013 where background measurements were made in a remote sequestration site with minimal infrastructure. The project provided opportunities for two graduate students to participate in research directly related to geologic carbon sequestration. Furthermore, commercialization of the technology developed is being pursued with five different companies via the Department of energy SBIR/STTR program« less

TeO$$_2$$ bolometers with Cherenkov signal tagging: towards next-generation neutrinoless double-beta decay experiments

DOE PAGES

Casali, N.; Vignati, Marco; Beeman, J. W.; ...

2015-01-14

CUORE, an array of 988 TeOmore » $$_2$$ bolometers, is about to be one of the most sensitive experiments searching for neutrinoless double-beta decay. Its sensitivity could be further improved by removing the background from α radioactivity. A few years ago it was pointed out that the signal from βs can be tagged by detecting the emitted Cherenkov light, which is not produced by αs. In this paper we confirm this possibility. For the first time we measured the Cherenkov light emitted by a CUORE crystal, and found it to be 100 eV at the Q-value of the decay. To completely reject the α background, we compute that one needs light detectors with baseline noise below 20 eV RMS, a value which is 3–4 times smaller than the average noise of the bolometric light detectors we are using. We point out that an improved light detector technology must be developed to obtain TeO$$_2$$ bolometric experiments able to probe the inverted hierarchy of neutrino masses.« less

Innovative Techniques to Model, Analyze and Monitor Space Effects on Air Force Space-Based Systems

DTIC Science & Technology

2010-03-20

of Comets in the Heliosphere as Observed by SMEI 4 2.8. Zodiacal Light Observations and Modeling 5 2.9. Space Weather Forecasting Lab (SWFL...This research resulted in two publications and a presentation at the 2007 American Geophysical Union Fall Meeting. 2.8. Zodiacal Light Observations...and Modeling One of the backgrounds removed from SMEI imagery is the scattered zodiacal light from solar system dust. The zodiacal light has

How does pea architecture influence light sharing in virtual wheat–pea mixtures? A simulation study based on pea genotypes with contrasting architectures

PubMed Central

Barillot, Romain; Combes, Didier; Chevalier, Valérie; Fournier, Christian; Escobar-Gutiérrez, Abraham J.

2012-01-01

Background and aims Light interception is a key factor driving the functioning of wheat–pea intercrops. The sharing of light is related to the canopy structure, which results from the architectural parameters of the mixed species. In the present study, we characterized six contrasting pea genotypes and identified architectural parameters whose range of variability leads to various levels of light sharing within virtual wheat–pea mixtures. Methodology Virtual plants were derived from magnetic digitizations performed during the growing cycle in a greenhouse experiment. Plant mock-ups were used as inputs of a radiative transfer model in order to estimate light interception in virtual wheat–pea mixtures. The turbid medium approach, extended to well-mixed canopies, was used as a framework for assessing the effects of leaf area index (LAI) and mean leaf inclination on light sharing. Principal results Three groups of pea genotypes were distinguished: (i) early and leafy cultivars, (ii) late semi-leafless cultivars and (iii) low-development semi-leafless cultivars. Within open canopies, light sharing was well described by the turbid medium approach and was therefore determined by the architectural parameters that composed LAI and foliage inclination. When canopy closure started, the turbid medium approach was unable to properly infer light partitioning because of the vertical structure of the canopy. This was related to the architectural parameters that determine the height of pea genotypes. Light capture was therefore affected by the development of leaflets, number of branches and phytomers, as well as internode length. Conclusions This study provides information on pea architecture and identifies parameters whose variability can be used to drive light sharing within wheat–pea mixtures. These results could be used to build up the architecture of pea ideotypes adapted to multi-specific stands towards light competition. PMID:23240074

Measurement of type-I edge localized mode pulse propagation in scrape-off layer using optical system of motional Stark effect diagnostics in JT-60U

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

Suzuki, T.; Oyama, N.; Asakura, N.

2010-04-15

Propagation of plasma ejected by type-I edge localized mode (ELM) has been measured in scrape-off layer (SOL) of the JT-60U tokamak, using optical system of motional Stark effect (MSE) diagnostics as beam emission spectroscopy (BES) diagnostics through a new technique developed. This MSE/BES system measures D{alpha} emission from heating neutral beam excited by collisions with the ejected plasma, as well as background light (e.g., bremsstrahlung). While spatio-temporal change in the beam emission gives information on propagation of the ejected plasma, the background light that is observed simultaneously in all spatial channels veils the information. In order to separate the beammore » emission and the background light, a two-wavelength detector is newly introduced into the MSE/BES system. The detector observes simultaneously at the same spatial point in two distinct wavelengths using two photomultiplier tubes through two interference filters. One of the filters is adjusted to the central wavelength of the beam emission for the MSE diagnostics, and the other is outside the beam emission spectrum. Eliminating the background light, temporal change in the net beam emission in the SOL has been evaluated. Comparing conditionally averaged beam emission with respect to 594 ELMs in a discharge at five spatial channels (0.02-0.3 m outside the main plasma near equatorial plane), radial velocity of the ELM pulse propagation in SOL is evaluated to be 0.8-1.8 km/s ({approx}1.4 km/s for least-mean-squared fitting).« less

Sensitivity of complex cells in cat striate cortex to relative motion.

PubMed

Hammond, P; Smith, A T

1984-06-03

Sensitivity of 95 complex cells to relative motion between oriented bars and textured backgrounds was investigated monocularly in the striate cortex of lightly anesthetized, paralyzed cats. Cells were classified conventionally. Those in deep layers were either direction-selective, or strongly preferred one direction of motion, and responded well to background texture motion alone: backgrounds potentiated the response to the bar in the cell's preferred direction when moved in phase, or in the opposite direction when moved in antiphase; other combinations depressed the level of response compared with that for the bar alone. The majority of direction-selective or strongly direction-biased cells in superficial layers behaved similarly. The most interesting superficial-layer cells were bidirectional or weakly direction-biased, and recorded closer to the cortical surface than the direction-selective neurons. A majority showed preference for relative motion, some for antiphase, others for in-phase motion, regardless of the absolute direction of motion across the receptive field, which could not be accounted for on the basis of separate responses to bars and backgrounds alone. Three of the superficial-layer direction-selective cells also showed preference for antiphase relative motion. In a few complex cells from superficial laminae, backgrounds were either without influence on responses to oriented stimuli, or purely suppressive. Visual backgrounds against which objects are perceived are usually neither featureless nor motionless: the results suggest that most complex cells in striate cortex are sensitive to the context in which objects are seen and susceptible to relationships between objects and their backgrounds in relative motion.

Mixing Heights and Three-Dimensional Ozone Structure Observed by Airborne Lidar During the 2006 Texas Air Quality Study

NASA Astrophysics Data System (ADS)

Hardesty, R. M.; Senff, C. J.; Alvarez, R. J.; Banta, R. M.; Sandberg, S. P.; Weickmann, A. M.; Darby, L. S.

2007-12-01

A new all solid state ozone lidar was deployed on a NOAA Twin Otter to study boundary layer ozone and aerosol, mostly around Houston, during the 2006 Texas Air Quality Study. The new instrument transmits high pulse-rate, low pulse-energy light at 3 wavelengths in the ultraviolet to obtain ozone profiles with 500 m horizontal resolution and 90 m vertical resolution. During the Texas field study, 20 research flights resulted in nearly 70 hours of ozone measurements during the period from August 1 to September 15. Science objectives included characterization of background ozone levels over rural areas near Houston and Dallas and variability and structure of the boundary layer over different surface types, including urban, wooded, and agricultural land surface areas as well as over Galveston Bay and the Gulf of Mexico. A histogram of all boundary layer ozone concentration measurements showed a bimodal distribution with modes at 45 ppb and 70 ppb. The lower mode correlated with southerly flow, when relatively clean air was transported onshore into the Houston area. Segmenting the observations during southerly flow by region, including the Gulf of Mexico, land within about 55 km from the coast, and further inland indicated that background levels increased by about 10 ppb as air was transported onshore. During the latter part of the experiment, as more pollution was imported into the Houston region, background levels rose to nearly 80 ppb in regions N of Houston. Two flights aimed at observing import of ozone into Texas from the east showed that ozone concentrations increased and boundary layer depths deepened upwind of Houston between September 4 and September 8. Background levels rose by more than 10 ppb over this period. In addition to ozone measurements, we also estimated boundary layer height based on maximum gradient in observed backscatter. The technique worked well when the layer topped by the strongest gradient extends down to the surface. Investigation of the correlation between ozone levels and mixing layer heights both within and external to the Houston urban plume showed a variety of relationships, depending on, e.g., wind direction and occurrence of a bay/gulf breeze. On a day-to-day basis, higher ozone levels were weakly correlated with deeper mixing levels - this was likely due to advection of the urban heat island downwind with the high-ozone urban plume.

Cost-effective elimination of lipofuscin fluorescence from formalin-fixed brain tissue by white phosphor light emitting diode array.

PubMed

Sun, Yulong; Chakrabartty, Avi

2016-12-01

Autofluorescence of aldehyde-fixed tissues greatly hinders fluorescence microscopy. In particular, lipofuscin, an autofluorescent component of aged brain tissue, complicates fluorescence imaging of tissue in neurodegenerative diseases. Background and lipofuscin fluorescence can be reduced by greater than 90% through photobleaching using white phosphor light emitting diode arrays prior to treatment with fluorescent probes. We compared the effect of photobleaching versus established chemical quenchers on the quality of fluorescent staining in formalin-fixed brain tissue of frontotemporal dementia with tau-positive inclusions. Unlike chemical quenchers, which reduced fluorescent probe signals as well as background, photobleaching treatment had no effect on probe fluorescence intensity while it effectively reduced background and lipofuscin fluorescence. The advantages and versatility of photobleaching over established methods are discussed.

Adaptive typography for dynamic mapping environments

NASA Astrophysics Data System (ADS)

Bardon, Didier

1991-08-01

When typography moves across a map, it passes over areas of different colors, densities, and textures. In such a dynamic environment, the aspect of typography must be constantly adapted to provide disernibility for every new background. Adaptive typography undergoes two adaptive operations: background control and contrast control. The background control prevents the features of the map (edges, lines, abrupt changes of densities) from destroying the integrity of the letterform. This is achieved by smoothing the features of the map in the area where a text label is displayed. The modified area is limited to the space covered by the characters of the label. Dispositions are taken to insure that the smoothing operation does not introduce any new visual noise. The contrast control assures that there are sufficient lightness differences between the typography and its ever-changing background. For every new situation, background color and foreground color are compared and the foreground color lightness is adjusted according to a chosen contrast value. Criteria and methods of choosing the appropriate contrast value are presented as well as the experiments that led to them.

The Gaussian Plasma Lens in Astrophysics: Refraction

NASA Astrophysics Data System (ADS)

Clegg, Andrew W.; Fey, Alan L.; Lazio, T. Joseph W.

1998-03-01

We present the geometrical optics for refraction of a distant background radio source by an interstellar plasma lens, with specific application to a lens with a Gaussian profile of free-electron column density. The refractive properties of the lens are specified completely by a dimensionless parameter α, which is a function of the wavelength of observation, the free-electron column density through the lens, the lens-observer distance, and the diameter of the lens transverse to the line of sight. A lens passing between the observer and a background source, due to the relative motions of the observer, lens, and source, produces modulations in the light curve of the background source. Because plasma lenses are diverging, the light curve displays a minimum in the background source's flux density, formed when the lens is on-axis, surrounded by enhancements above the nominal (unlensed) flux density. The exact form of the light curve depends only upon the parameter α and the relative angular sizes of the source and lens as seen by the observer. Other effects due to lensing include the following: (1) the formation of caustic surfaces, upon which the apparent brightness of the background source becomes very large; (2) the possible creation of multiple images of the background source; and (3) angular position wander of the background source. If caustics are formed, the separation of the outer caustics can be used to constrain α, while the separation of the inner caustics can constrain the size of the lens. We apply our analysis to two sources, which have undergone extreme scattering events: (1) 0954+658, a source for which we can identify multiple caustics in its light curve, and (2) 1741-038, for which polarization observations were obtained during and after the scattering event. We find general agreement between modeled and observed light curves at 2.25 GHz, but poor agreement at 8.1 GHz. The discrepancies between the modeled and observed light curves may result from some combination of substructure within the lens, an anisotropic lens shape, a lens which only grazes the source rather than passing completely over it, or unresolved substructure within the extragalactic sources. Our analysis also allows us to place constraints on the physical characteristics of the lens. The inferred properties of the lens responsible for the scattering event toward 0954+658 (1741-038) are that it was 0.38 AU (0.065 AU) in diameter with a peak column density of 0.24 pc cm-3 (10-4 pc cm-3), an electron density within the lens of 105 cm-3 (300 cm-3), and a mass of 6.5 × 10-14 M⊙ (10-18 M⊙). The angular position wander caused by the lens was 250 mas (0.4 mas) at 2.25 GHz. In the case of 1741-038, we can place an upper limit of only 100 mG on the magnetic field within the lens.

Late-time structure of the Bunch-Davies de Sitter wavefunction

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

Anninos, Dionysios; Anous, Tarek; Freedman, Daniel Z.

2015-11-30

We examine the late time behavior of the Bunch-Davies wavefunction for interacting light fields in a de Sitter background. We use perturbative techniques developed in the framework of AdS/CFT, and analytically continue to compute tree and loop level contributions to the Bunch-Davies wavefunction. We consider self-interacting scalars of general mass, but focus especially on the massless and conformally coupled cases. We show that certain contributions grow logarithmically in conformal time both at tree and loop level. We also consider gauge fields and gravitons. The four-dimensional Fefferman-Graham expansion of classical asymptotically de Sitter solutions is used to show that the wavefunctionmore » contains no logarithmic growth in the pure graviton sector at tree level. Finally, assuming a holographic relation between the wavefunction and the partition function of a conformal field theory, we interpret the logarithmic growths in the language of conformal field theory.« less

Improved Upper Limits on the Stochastic Gravitational-Wave Background from 2009-2010 LIGO and Virgo Data

NASA Astrophysics Data System (ADS)

Aasi, J.; Abbott, B. P.; Abbott, R.; Abbott, T.; Abernathy, M. R.; Accadia, T.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Affeldt, C.; Agathos, M.; Aggarwal, N.; Aguiar, O. D.; Ain, A.; Ajith, P.; Alemic, A.; Allen, B.; Allocca, A.; Amariutei, D.; Andersen, M.; Anderson, R.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Araya, M. C.; Arceneaux, C.; Areeda, J.; Aston, S. M.; Astone, P.; Aufmuth, P.; Aulbert, C.; Austin, L.; Aylott, B. E.; Babak, S.; Baker, P. T.; Ballardin, G.; Ballmer, S. W.; Barayoga, J. C.; Barbet, M.; Barish, B. C.; Barker, D.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barton, M. A.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Bauchrowitz, J.; Bauer, Th. S.; Behnke, B.; Bejger, M.; Beker, M. G.; Belczynski, C.; Bell, A. S.; Bell, C.; Bergmann, G.; Bersanetti, D.; Bertolini, A.; Betzwieser, J.; Beyersdorf, P. T.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Biscans, S.; Bitossi, M.; Bizouard, M. A.; Black, E.; Blackburn, J. K.; Blackburn, L.; Blair, D.; Bloemen, S.; Blom, M.; Bock, O.; Bodiya, T. P.; Boer, M.; Bogaert, G.; Bogan, C.; Bond, C.; Bondu, F.; Bonelli, L.; Bonnand, R.; Bork, R.; Born, M.; Boschi, V.; Bose, Sukanta; Bosi, L.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Branchesi, M.; Brau, J. E.; Briant, T.; Bridges, D. O.; Brillet, A.; Brinkmann, M.; Brisson, V.; Brooks, A. F.; Brown, D. A.; Brown, D. D.; Brückner, F.; Buchman, S.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Burman, R.; Buskulic, D.; Buy, C.; Cadonati, L.; Cagnoli, G.; Bustillo, J. Calderón; Calloni, E.; Camp, J. B.; Campsie, P.; Cannon, K. C.; Canuel, B.; Cao, J.; Capano, C. D.; Carbognani, F.; Carbone, L.; Caride, S.; Castiglia, A.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Celerier, C.; Cella, G.; Cepeda, C.; Cesarini, E.; Chakraborty, R.; Chalermsongsak, T.; Chamberlin, S. J.; Chao, S.; Charlton, P.; Chassande-Mottin, E.; Chen, X.; Chen, Y.; Chincarini, A.; Chiummo, A.; Cho, H. S.; Chow, J.; Christensen, N.; Chu, Q.; Chua, S. S. Y.; Chung, S.; Ciani, G.; Clara, F.; Clark, J. A.; Cleva, F.; Coccia, E.; Cohadon, P.-F.; Colla, A.; Collette, C.; Colombini, M.; Cominsky, L.; Constancio, M.; Conte, A.; Cook, D.; Corbitt, T. R.; Cordier, M.; Cornish, N.; Corpuz, A.; Corsi, A.; Costa, C. A.; Coughlin, M. W.; Coughlin, S.; Coulon, J.-P.; Countryman, S.; Couvares, P.; Coward, D. M.; Cowart, M.; Coyne, D. C.; Coyne, R.; Craig, K.; Creighton, J. D. E.; Crowder, S. G.; Cumming, A.; Cunningham, L.; Cuoco, E.; Dahl, K.; Canton, T. Dal; Damjanic, M.; Danilishin, S. L.; D'Antonio, S.; Danzmann, K.; Dattilo, V.; Daveloza, H.; Davier, M.; Davies, G. S.; Daw, E. J.; Day, R.; Dayanga, T.; Debreczeni, G.; Degallaix, J.; Deléglise, S.; Del Pozzo, W.; Denker, T.; Dent, T.; Dereli, H.; Dergachev, V.; De Rosa, R.; DeRosa, R. T.; DeSalvo, R.; Dhurandhar, S.; Díaz, M.; Di Fiore, L.; Di Lieto, A.; Di Palma, I.; Di Virgilio, A.; Donath, A.; Donovan, F.; Dooley, K. L.; Doravari, S.; Dossa, S.; Douglas, R.; Downes, T. P.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Du, Z.; Dwyer, S.; Eberle, T.; Edo, T.; Edwards, M.; Effler, A.; Eggenstein, H.; Ehrens, P.; Eichholz, J.; Eikenberry, S. S.; Endrőczi, G.; Essick, R.; Etzel, T.; Evans, M.; Evans, T.; Factourovich, M.; Fafone, V.; Fairhurst, S.; Fang, Q.; Farinon, S.; Farr, B.; Farr, W. M.; Favata, M.; Fehrmann, H.; Fejer, M. M.; Feldbaum, D.; Feroz, F.; Ferrante, I.; Ferrini, F.; Fidecaro, F.; Finn, L. S.; Fiori, I.; Fisher, R. P.; Flaminio, R.; Fournier, J.-D.; Franco, S.; Frasca, S.; Frasconi, F.; Frede, M.; Frei, Z.; Freise, A.; Frey, R.; Fricke, T. T.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Gair, J.; Gammaitoni, L.; Gaonkar, S.; Garufi, F.; Gehrels, N.; Gemme, G.; Genin, E.; Gennai, A.; Ghosh, S.; Giaime, J. A.; Giardina, K. D.; Giazotto, A.; Gill, C.; Gleason, J.; Goetz, E.; Goetz, R.; Gondan, L.; González, G.; Gordon, N.; Gorodetsky, M. L.; Gossan, S.; Goßler, S.; Gouaty, R.; Gräf, C.; Graff, P. B.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greenhalgh, R. J. S.; Gretarsson, A. M.; Groot, P.; Grote, H.; Grover, K.; Grunewald, S.; Guidi, G. M.; Guido, C.; Gushwa, K.; Gustafson, E. K.; Gustafson, R.; Hammer, D.; Hammond, G.; Hanke, M.; Hanks, J.; Hanna, C.; Hanson, J.; Harms, J.; Harry, G. M.; Harry, I. W.; Harstad, E. D.; Hart, M.; Hartman, M. T.; Haster, C.-J.; Haughian, K.; Heidmann, A.; Heintze, M.; Heitmann, H.; Hello, P.; Hemming, G.; Hendry, M.; Heng, I. S.; Heptonstall, A. W.; Heurs, M.; Hewitson, M.; Hild, S.; Hoak, D.; Hodge, K. A.; Holt, K.; Hooper, S.; Hopkins, P.; Hosken, D. J.; Hough, J.; Howell, E. J.; Hu, Y.; Huerta, E.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh, M.; Huynh-Dinh, T.; Ingram, D. R.; Inta, R.; Isogai, T.; Ivanov, A.; Iyer, B. R.; Izumi, K.; Jacobson, M.; James, E.; Jang, H.; Jaranowski, P.; Ji, Y.; Jiménez-Forteza, F.; Johnson, W. W.; Jones, D. I.; Jones, R.; Jonker, R. J. G.; Ju, L.; Haris, K.; Kalmus, P.; Kalogera, V.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Karlen, J.; Kasprzack, M.; Katsavounidis, E.; Katzman, W.; Kaufer, H.; Kawabe, K.; Kawazoe, F.; Kéfélian, F.; Keiser, G. M.; Keitel, D.; Kelley, D. B.; Kells, W.; Khalaidovski, A.; Khalili, F. Y.; Khazanov, E. A.; Kim, C.; Kim, K.; Kim, N.; Kim, N. G.; Kim, Y.-M.; King, E. J.; King, P. J.; Kinzel, D. L.; Kissel, J. S.; Klimenko, S.; Kline, J.; Koehlenbeck, S.; Kokeyama, K.; Kondrashov, V.; Koranda, S.; Korth, W. Z.; Kowalska, I.; Kozak, D. B.; Kremin, A.; Kringel, V.; Królak, A.; Kuehn, G.; Kumar, A.; Kumar, P.; Kumar, R.; Kuo, L.; Kutynia, A.; Kwee, P.; Landry, M.; Lantz, B.; Larson, S.; Lasky, P. D.; Lawrie, C.; Lazzarini, A.; Lazzaro, C.; Leaci, P.; Leavey, S.; Lebigot, E. O.; Lee, C.-H.; Lee, H. K.; Lee, H. M.; Lee, J.; Leonardi, M.; Leong, J. R.; Le Roux, A.; Leroy, N.; Letendre, N.; Levin, Y.; Levine, B.; Lewis, J.; Li, T. G. F.; Libbrecht, K.; Libson, A.; Lin, A. C.; Littenberg, T. B.; Litvine, V.; Lockerbie, N. A.; Lockett, V.; Lodhia, D.; Loew, K.; Logue, J.; Lombardi, A. L.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lough, J.; Lubinski, M. J.; Lück, H.; Luijten, E.; Lundgren, A. P.; Lynch, R.; Ma, Y.; Macarthur, J.; Macdonald, E. P.; MacDonald, T.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Magana-Sandoval, F.; Mageswaran, M.; Maglione, C.; Mailand, K.; Majorana, E.; Maksimovic, I.; Malvezzi, V.; Man, N.; Manca, G. M.; Mandel, I.; Mandic, V.; Mangano, V.; Mangini, N.; Mantovani, M.; Marchesoni, F.; Marion, F.; Márka, S.; Márka, Z.; Markosyan, A.; Maros, E.; Marque, J.; Martelli, F.; Martin, I. W.; Martin, R. M.; Martinelli, L.; Martynov, D.; Marx, J. N.; Mason, K.; Masserot, A.; Massinger, T. J.; Matichard, F.; Matone, L.; Matzner, R. A.; Mavalvala, N.; Mazumder, N.; Mazzolo, G.; McCarthy, R.; McClelland, D. E.; McGuire, S. C.; McIntyre, G.; McIver, J.; McLin, K.; Meacher, D.; Meadors, G. D.; Mehmet, M.; Meidam, J.; Meinders, M.; Melatos, A.; Mendell, G.; Mercer, R. A.; Meshkov, S.; Messenger, C.; Meyers, P.; Miao, H.; Michel, C.; Mikhailov, E. E.; Milano, L.; Milde, S.; Miller, J.; Minenkov, Y.; Mingarelli, C. M. F.; Mishra, C.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moe, B.; Moesta, P.; Mohan, M.; Mohapatra, S. R. P.; Moraru, D.; Moreno, G.; Morgado, N.; Morriss, S. R.; Mossavi, K.; Mours, B.; Mow-Lowry, C. M.; Mueller, C. L.; Mueller, G.; Mukherjee, S.; Mullavey, A.; Munch, J.; Murphy, D.; Murray, P. G.; Mytidis, A.; Nagy, M. F.; Kumar, D. Nanda; Nardecchia, I.; Naticchioni, L.; Nayak, R. K.; Necula, V.; Nelemans, G.; Neri, I.; Neri, M.; Newton, G.; Nguyen, T.; Nitz, A.; Nocera, F.; Nolting, D.; Normandin, M. E. N.; Nuttall, L. K.; Ochsner, E.; O'Dell, J.; Oelker, E.; Oh, J. J.; Oh, S. H.; Ohme, F.; Oppermann, P.; O'Reilly, B.; O'Shaughnessy, R.; Osthelder, C.; Ottaway, D. J.; Ottens, R. S.; Overmier, H.; Owen, B. J.; Padilla, C.; Pai, A.; Palashov, O.; Palomba, C.; Pan, H.; Pan, Y.; Pankow, C.; Paoletti, F.; Paoletti, R.; Paris, H.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Pedraza, M.; Penn, S.; Perreca, A.; Phelps, M.; Pichot, M.; Pickenpack, M.; Piergiovanni, F.; Pierro, V.; Pinard, L.; Pinto, I. M.; Pitkin, M.; Poeld, J.; Poggiani, R.; Poteomkin, A.; Powell, J.; Prasad, J.; Premachandra, S.; Prestegard, T.; Price, L. R.; Prijatelj, M.; Privitera, S.; Prodi, G. A.; Prokhorov, L.; Puncken, O.; Punturo, M.; Puppo, P.; Qin, J.; Quetschke, V.; Quintero, E.; Quiroga, G.; Quitzow-James, R.; Raab, F. J.; Rabeling, D. S.; Rácz, I.; Radkins, H.; Raffai, P.; Raja, S.; Rajalakshmi, G.; Rakhmanov, M.; Ramet, C.; Ramirez, K.; Rapagnani, P.; Raymond, V.; Re, V.; Read, J.; Reed, C. M.; Regimbau, T.; Reid, S.; Reitze, D. H.; Rhoades, E.; Ricci, F.; Riles, K.; Robertson, N. A.; Robinet, F.; Rocchi, A.; Rodruck, M.; Rolland, L.; Rollins, J. G.; Romano, J. D.; Romano, R.; Romanov, G.; Romie, J. H.; Rosińska, D.; Rowan, S.; Rüdiger, A.; Ruggi, P.; Ryan, K.; Salemi, F.; Sammut, L.; Sandberg, V.; Sanders, J. R.; Sannibale, V.; Santiago-Prieto, I.; Saracco, E.; Sassolas, B.; Sathyaprakash, B. S.; Saulson, P. R.; Savage, R.; Scheuer, J.; Schilling, R.; Schnabel, R.; Schofield, R. M. S.; Schreiber, E.; Schuette, D.; Schutz, B. F.; Scott, J.; Scott, S. M.; Sellers, D.; Sengupta, A. S.; Sentenac, D.; Sequino, V.; Sergeev, A.; Shaddock, D.; Shah, S.; Shahriar, M. S.; Shaltev, M.; Shapiro, B.; Shawhan, P.; Shoemaker, D. H.; Sidery, T. L.; Siellez, K.; Siemens, X.; Sigg, D.; Simakov, D.; Singer, A.; Singer, L.; Singh, R.; Sintes, A. M.; Slagmolen, B. J. J.; Slutsky, J.; Smith, J. R.; Smith, M.; Smith, R. J. E.; Smith-Lefebvre, N. D.; Son, E. J.; Sorazu, B.; Souradeep, T.; Sperandio, L.; Staley, A.; Stebbins, J.; Steinlechner, J.; Steinlechner, S.; Stephens, B. C.; Steplewski, S.; Stevenson, S.; Stone, R.; Stops, D.; Strain, K. A.; Straniero, N.; Strigin, S.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Susmithan, S.; Sutton, P. J.; Swinkels, B.; Tacca, M.; Talukder, D.; Tanner, D. B.; Tarabrin, S. P.; Taylor, R.; ter Braack, A. P. M.; Thirugnanasambandam, M. P.; Thomas, M.; Thomas, P.; Thorne, K. A.; Thorne, K. S.; Thrane, E.; Tiwari, V.; Tokmakov, K. V.; Tomlinson, C.; Toncelli, A.; Tonelli, M.; Torre, O.; Torres, C. V.; Torrie, C. I.; Travasso, F.; Traylor, G.; Tse, M.; Ugolini, D.; Unnikrishnan, C. S.; Urban, A. L.; Urbanek, K.; Vahlbruch, H.; Vajente, G.; Valdes, G.; Vallisneri, M.; van den Brand, J. F. J.; Van Den Broeck, C.; van der Putten, S.; van der Sluys, M. V.; van Heijningen, J.; van Veggel, A. A.; Vass, S.; Vasúth, M.; Vaulin, R.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P. J.; Venkateswara, K.; Verkindt, D.; Verma, S. S.; Vetrano, F.; Viceré, A.; Vincent-Finley, R.; Vinet, J.-Y.; Vitale, S.; Vo, T.; Vocca, H.; Vorvick, C.; Vousden, W. D.; Vyachanin, S. P.; Wade, A.; Wade, L.; Wade, M.; Walker, M.; Wallace, L.; Wang, M.; Wang, X.; Ward, R. L.; Was, M.; Weaver, B.; Wei, L.-W.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Welborn, T.; Wen, L.; Wessels, P.; West, M.; Westphal, T.; Wette, K.; Whelan, J. T.; White, D. J.; Whiting, B. F.; Wiesner, K.; Wilkinson, C.; Williams, K.; Williams, L.; Williams, R.; Williams, T.; Williamson, A. R.; Willis, J. L.; Willke, B.; Wimmer, M.; Winkler, W.; Wipf, C. C.; Wiseman, A. G.; Wittel, H.; Woan, G.; Worden, J.; Yablon, J.; Yakushin, I.; Yamamoto, H.; Yancey, C. C.; Yang, H.; Yang, Z.; Yoshida, S.; Yvert, M.; ZadroŻny, A.; Zanolin, M.; Zendri, J.-P.; Zhang, Fan; Zhang, L.; Zhao, C.; Zhu, X. J.; Zucker, M. E.; Zuraw, S.; Zweizig, J.; LIGO; Virgo Collaboration

2014-12-01

Gravitational waves from a variety of sources are predicted to superpose to create a stochastic background. This background is expected to contain unique information from throughout the history of the Universe that is unavailable through standard electromagnetic observations, making its study of fundamental importance to understanding the evolution of the Universe. We carry out a search for the stochastic background with the latest data from the LIGO and Virgo detectors. Consistent with predictions from most stochastic gravitational-wave background models, the data display no evidence of a stochastic gravitational-wave signal. Assuming a gravitational-wave spectrum of ΩGW(f )=Ωα(f/fref ) α , we place 95% confidence level upper limits on the energy density of the background in each of four frequency bands spanning 41.5-1726 Hz. In the frequency band of 41.5-169.25 Hz for a spectral index of α =0 , we constrain the energy density of the stochastic background to be ΩGW(f )<5.6 ×1 0-6 . For the 600-1000 Hz band, ΩGW(f )<0.14 (f /900 Hz )3 , a factor of 2.5 lower than the best previously reported upper limits. We find ΩGW(f )<1.8 ×1 0-4 using a spectral index of zero for 170-600 Hz and ΩGW(f )<1.0 (f /1300 Hz )3 for 1000-1726 Hz, bands in which no previous direct limits have been placed. The limits in these four bands are the lowest direct measurements to date on the stochastic background. We discuss the implications of these results in light of the recent claim by the BICEP2 experiment of the possible evidence for inflationary gravitational waves.

Improved upper limits on the stochastic gravitational-wave background from 2009-2010 LIGO and Virgo data.

PubMed

Aasi, J; Abbott, B P; Abbott, R; Abbott, T; Abernathy, M R; Accadia, T; Acernese, F; Ackley, K; Adams, C; Adams, T; Addesso, P; Adhikari, R X; Affeldt, C; Agathos, M; Aggarwal, N; Aguiar, O D; Ain, A; Ajith, P; Alemic, A; Allen, B; Allocca, A; Amariutei, D; Andersen, M; Anderson, R; Anderson, S B; Anderson, W G; Arai, K; Araya, M C; Arceneaux, C; Areeda, J; Aston, S M; Astone, P; Aufmuth, P; Aulbert, C; Austin, L; Aylott, B E; Babak, S; Baker, P T; Ballardin, G; Ballmer, S W; Barayoga, J C; Barbet, M; Barish, B C; Barker, D; Barone, F; Barr, B; Barsotti, L; Barsuglia, M; Barton, M A; Bartos, I; Bassiri, R; Basti, A; Batch, J C; Bauchrowitz, J; Bauer, Th S; Behnke, B; Bejger, M; Beker, M G; Belczynski, C; Bell, A S; Bell, C; Bergmann, G; Bersanetti, D; Bertolini, A; Betzwieser, J; Beyersdorf, P T; Bilenko, I A; Billingsley, G; Birch, J; Biscans, S; Bitossi, M; Bizouard, M A; Black, E; Blackburn, J K; Blackburn, L; Blair, D; Bloemen, S; Blom, M; Bock, O; Bodiya, T P; Boer, M; Bogaert, G; Bogan, C; Bond, C; Bondu, F; Bonelli, L; Bonnand, R; Bork, R; Born, M; Boschi, V; Bose, Sukanta; Bosi, L; Bradaschia, C; Brady, P R; Braginsky, V B; Branchesi, M; Brau, J E; Briant, T; Bridges, D O; Brillet, A; Brinkmann, M; Brisson, V; Brooks, A F; Brown, D A; Brown, D D; Brückner, F; Buchman, S; Bulik, T; Bulten, H J; Buonanno, A; Burman, R; Buskulic, D; Buy, C; Cadonati, L; Cagnoli, G; Bustillo, J Calderón; Calloni, E; Camp, J B; Campsie, P; Cannon, K C; Canuel, B; Cao, J; Capano, C D; Carbognani, F; Carbone, L; Caride, S; Castiglia, A; Caudill, S; Cavaglià, M; Cavalier, F; Cavalieri, R; Celerier, C; Cella, G; Cepeda, C; Cesarini, E; Chakraborty, R; Chalermsongsak, T; Chamberlin, S J; Chao, S; Charlton, P; Chassande-Mottin, E; Chen, X; Chen, Y; Chincarini, A; Chiummo, A; Cho, H S; Chow, J; Christensen, N; Chu, Q; Chua, S S Y; Chung, S; Ciani, G; Clara, F; Clark, J A; Cleva, F; Coccia, E; Cohadon, P-F; Colla, A; Collette, C; Colombini, M; Cominsky, L; Constancio, M; Conte, A; Cook, D; Corbitt, T R; Cordier, M; Cornish, N; Corpuz, A; Corsi, A; Costa, C A; Coughlin, M W; Coughlin, S; Coulon, J-P; Countryman, S; Couvares, P; Coward, D M; Cowart, M; Coyne, D C; Coyne, R; Craig, K; Creighton, J D E; Crowder, S G; Cumming, A; Cunningham, L; Cuoco, E; Dahl, K; Canton, T Dal; Damjanic, M; Danilishin, S L; D'Antonio, S; Danzmann, K; Dattilo, V; Daveloza, H; Davier, M; Davies, G S; Daw, E J; Day, R; Dayanga, T; Debreczeni, G; Degallaix, J; Deléglise, S; Del Pozzo, W; Denker, T; Dent, T; Dereli, H; Dergachev, V; De Rosa, R; DeRosa, R T; DeSalvo, R; Dhurandhar, S; Díaz, M; Di Fiore, L; Di Lieto, A; Di Palma, I; Di Virgilio, A; Donath, A; Donovan, F; Dooley, K L; Doravari, S; Dossa, S; Douglas, R; Downes, T P; Drago, M; Drever, R W P; Driggers, J C; Du, Z; Dwyer, S; Eberle, T; Edo, T; Edwards, M; Effler, A; Eggenstein, H; Ehrens, P; Eichholz, J; Eikenberry, S S; Endrőczi, G; Essick, R; Etzel, T; Evans, M; Evans, T; Factourovich, M; Fafone, V; Fairhurst, S; Fang, Q; Farinon, S; Farr, B; Farr, W M; Favata, M; Fehrmann, H; Fejer, M M; Feldbaum, D; Feroz, F; Ferrante, I; Ferrini, F; Fidecaro, F; Finn, L S; Fiori, I; Fisher, R P; Flaminio, R; Fournier, J-D; Franco, S; Frasca, S; Frasconi, F; Frede, M; Frei, Z; Freise, A; Frey, R; Fricke, T T; Fritschel, P; Frolov, V V; Fulda, P; Fyffe, M; Gair, J; Gammaitoni, L; Gaonkar, S; Garufi, F; Gehrels, N; Gemme, G; Genin, E; Gennai, A; Ghosh, S; Giaime, J A; Giardina, K D; Giazotto, A; Gill, C; Gleason, J; Goetz, E; Goetz, R; Gondan, L; González, G; Gordon, N; Gorodetsky, M L; Gossan, S; Gossler, S; Gouaty, R; Gräf, C; Graff, P B; Granata, M; Grant, A; Gras, S; Gray, C; Greenhalgh, R J S; Gretarsson, A M; Groot, P; Grote, H; Grover, K; Grunewald, S; Guidi, G M; Guido, C; Gushwa, K; Gustafson, E K; Gustafson, R; Hammer, D; Hammond, G; Hanke, M; Hanks, J; Hanna, C; Hanson, J; Harms, J; Harry, G M; Harry, I W; Harstad, E D; Hart, M; Hartman, M T; Haster, C-J; Haughian, K; Heidmann, A; Heintze, M; Heitmann, H; Hello, P; Hemming, G; Hendry, M; Heng, I S; Heptonstall, A W; Heurs, M; Hewitson, M; Hild, S; Hoak, D; Hodge, K A; Holt, K; Hooper, S; Hopkins, P; Hosken, D J; Hough, J; Howell, E J; Hu, Y; Huerta, E; Hughey, B; Husa, S; Huttner, S H; Huynh, M; Huynh-Dinh, T; Ingram, D R; Inta, R; Isogai, T; Ivanov, A; Iyer, B R; Izumi, K; Jacobson, M; James, E; Jang, H; Jaranowski, P; Ji, Y; Jiménez-Forteza, F; Johnson, W W; Jones, D I; Jones, R; Jonker, R J G; Ju, L; K, Haris; Kalmus, P; Kalogera, V; Kandhasamy, S; Kang, G; Kanner, J B; Karlen, J; Kasprzack, M; Katsavounidis, E; Katzman, W; Kaufer, H; Kawabe, K; Kawazoe, F; Kéfélian, F; Keiser, G M; Keitel, D; Kelley, D B; Kells, W; Khalaidovski, A; Khalili, F Y; Khazanov, E A; Kim, C; Kim, K; Kim, N; Kim, N G; Kim, Y-M; King, E J; King, P J; Kinzel, D L; Kissel, J S; Klimenko, S; Kline, J; Koehlenbeck, S; Kokeyama, K; Kondrashov, V; Koranda, S; Korth, W Z; Kowalska, I; Kozak, D B; Kremin, A; Kringel, V; Królak, A; Kuehn, G; Kumar, A; Kumar, P; Kumar, R; Kuo, L; Kutynia, A; Kwee, P; Landry, M; Lantz, B; Larson, S; Lasky, P D; Lawrie, C; Lazzarini, A; Lazzaro, C; Leaci, P; Leavey, S; Lebigot, E O; Lee, C-H; Lee, H K; Lee, H M; Lee, J; Leonardi, M; Leong, J R; Le Roux, A; Leroy, N; Letendre, N; Levin, Y; Levine, B; Lewis, J; Li, T G F; Libbrecht, K; Libson, A; Lin, A C; Littenberg, T B; Litvine, V; Lockerbie, N A; Lockett, V; Lodhia, D; Loew, K; Logue, J; Lombardi, A L; Lorenzini, M; Loriette, V; Lormand, M; Losurdo, G; Lough, J; Lubinski, M J; Lück, H; Luijten, E; Lundgren, A P; Lynch, R; Ma, Y; Macarthur, J; Macdonald, E P; MacDonald, T; Machenschalk, B; MacInnis, M; Macleod, D M; Magana-Sandoval, F; Mageswaran, M; Maglione, C; Mailand, K; Majorana, E; Maksimovic, I; Malvezzi, V; Man, N; Manca, G M; Mandel, I; Mandic, V; Mangano, V; Mangini, N; Mantovani, M; Marchesoni, F; Marion, F; Márka, S; Márka, Z; Markosyan, A; Maros, E; Marque, J; Martelli, F; Martin, I W; Martin, R M; Martinelli, L; Martynov, D; Marx, J N; Mason, K; Masserot, A; Massinger, T J; Matichard, F; Matone, L; Matzner, R A; Mavalvala, N; Mazumder, N; Mazzolo, G; McCarthy, R; McClelland, D E; McGuire, S C; McIntyre, G; McIver, J; McLin, K; Meacher, D; Meadors, G D; Mehmet, M; Meidam, J; Meinders, M; Melatos, A; Mendell, G; Mercer, R A; Meshkov, S; Messenger, C; Meyers, P; Miao, H; Michel, C; Mikhailov, E E; Milano, L; Milde, S; Miller, J; Minenkov, Y; Mingarelli, C M F; Mishra, C; Mitra, S; Mitrofanov, V P; Mitselmakher, G; Mittleman, R; Moe, B; Moesta, P; Mohan, M; Mohapatra, S R P; Moraru, D; Moreno, G; Morgado, N; Morriss, S R; Mossavi, K; Mours, B; Mow-Lowry, C M; Mueller, C L; Mueller, G; Mukherjee, S; Mullavey, A; Munch, J; Murphy, D; Murray, P G; Mytidis, A; Nagy, M F; Kumar, D Nanda; Nardecchia, I; Naticchioni, L; Nayak, R K; Necula, V; Nelemans, G; Neri, I; Neri, M; Newton, G; Nguyen, T; Nitz, A; Nocera, F; Nolting, D; Normandin, M E N; Nuttall, L K; Ochsner, E; O'Dell, J; Oelker, E; Oh, J J; Oh, S H; Ohme, F; Oppermann, P; O'Reilly, B; O'Shaughnessy, R; Osthelder, C; Ottaway, D J; Ottens, R S; Overmier, H; Owen, B J; Padilla, C; Pai, A; Palashov, O; Palomba, C; Pan, H; Pan, Y; Pankow, C; Paoletti, F; Paoletti, R; Paris, H; Pasqualetti, A; Passaquieti, R; Passuello, D; Pedraza, M; Penn, S; Perreca, A; Phelps, M; Pichot, M; Pickenpack, M; Piergiovanni, F; Pierro, V; Pinard, L; Pinto, I M; Pitkin, M; Poeld, J; Poggiani, R; Poteomkin, A; Powell, J; Prasad, J; Premachandra, S; Prestegard, T; Price, L R; Prijatelj, M; Privitera, S; Prodi, G A; Prokhorov, L; Puncken, O; Punturo, M; Puppo, P; Qin, J; Quetschke, V; Quintero, E; Quiroga, G; Quitzow-James, R; Raab, F J; Rabeling, D S; Rácz, I; Radkins, H; Raffai, P; Raja, S; Rajalakshmi, G; Rakhmanov, M; Ramet, C; Ramirez, K; Rapagnani, P; Raymond, V; Re, V; Read, J; Reed, C M; Regimbau, T; Reid, S; Reitze, D H; Rhoades, E; Ricci, F; Riles, K; Robertson, N A; Robinet, F; Rocchi, A; Rodruck, M; Rolland, L; Rollins, J G; Romano, J D; Romano, R; Romanov, G; Romie, J H; Rosińska, D; Rowan, S; Rüdiger, A; Ruggi, P; Ryan, K; Salemi, F; Sammut, L; Sandberg, V; Sanders, J R; Sannibale, V; Santiago-Prieto, I; Saracco, E; Sassolas, B; Sathyaprakash, B S; Saulson, P R; Savage, R; Scheuer, J; Schilling, R; Schnabel, R; Schofield, R M S; Schreiber, E; Schuette, D; Schutz, B F; Scott, J; Scott, S M; Sellers, D; Sengupta, A S; Sentenac, D; Sequino, V; Sergeev, A; Shaddock, D; Shah, S; Shahriar, M S; Shaltev, M; Shapiro, B; Shawhan, P; Shoemaker, D H; Sidery, T L; Siellez, K; Siemens, X; Sigg, D; Simakov, D; Singer, A; Singer, L; Singh, R; Sintes, A M; Slagmolen, B J J; Slutsky, J; Smith, J R; Smith, M; Smith, R J E; Smith-Lefebvre, N D; Son, E J; Sorazu, B; Souradeep, T; Sperandio, L; Staley, A; Stebbins, J; Steinlechner, J; Steinlechner, S; Stephens, B C; Steplewski, S; Stevenson, S; Stone, R; Stops, D; Strain, K A; Straniero, N; Strigin, S; Sturani, R; Stuver, A L; Summerscales, T Z; Susmithan, S; Sutton, P J; Swinkels, B; Tacca, M; Talukder, D; Tanner, D B; Tarabrin, S P; Taylor, R; Ter Braack, A P M; Thirugnanasambandam, M P; Thomas, M; Thomas, P; Thorne, K A; Thorne, K S; Thrane, E; Tiwari, V; Tokmakov, K V; Tomlinson, C; Toncelli, A; Tonelli, M; Torre, O; Torres, C V; Torrie, C I; Travasso, F; Traylor, G; Tse, M; Ugolini, D; Unnikrishnan, C S; Urban, A L; Urbanek, K; Vahlbruch, H; Vajente, G; Valdes, G; Vallisneri, M; van den Brand, J F J; Van Den Broeck, C; van der Putten, S; van der Sluys, M V; van Heijningen, J; van Veggel, A A; Vass, S; Vasúth, M; Vaulin, R; Vecchio, A; Vedovato, G; Veitch, J; Veitch, P J; Venkateswara, K; Verkindt, D; Verma, S S; Vetrano, F; Viceré, A; Vincent-Finley, R; Vinet, J-Y; Vitale, S; Vo, T; Vocca, H; Vorvick, C; Vousden, W D; Vyachanin, S P; Wade, A; Wade, L; Wade, M; Walker, M; Wallace, L; Wang, M; Wang, X; Ward, R L; Was, M; Weaver, B; Wei, L-W; Weinert, M; Weinstein, A J; Weiss, R; Welborn, T; Wen, L; Wessels, P; West, M; Westphal, T; Wette, K; Whelan, J T; White, D J; Whiting, B F; Wiesner, K; Wilkinson, C; Williams, K; Williams, L; Williams, R; Williams, T; Williamson, A R; Willis, J L; Willke, B; Wimmer, M; Winkler, W; Wipf, C C; Wiseman, A G; Wittel, H; Woan, G; Worden, J; Yablon, J; Yakushin, I; Yamamoto, H; Yancey, C C; Yang, H; Yang, Z; Yoshida, S; Yvert, M; Zadrożny, A; Zanolin, M; Zendri, J-P; Zhang, Fan; Zhang, L; Zhao, C; Zhu, X J; Zucker, M E; Zuraw, S; Zweizig, J

2014-12-05

Gravitational waves from a variety of sources are predicted to superpose to create a stochastic background. This background is expected to contain unique information from throughout the history of the Universe that is unavailable through standard electromagnetic observations, making its study of fundamental importance to understanding the evolution of the Universe. We carry out a search for the stochastic background with the latest data from the LIGO and Virgo detectors. Consistent with predictions from most stochastic gravitational-wave background models, the data display no evidence of a stochastic gravitational-wave signal. Assuming a gravitational-wave spectrum of Ω_{GW}(f)=Ω_{α}(f/f_{ref})^{α}, we place 95% confidence level upper limits on the energy density of the background in each of four frequency bands spanning 41.5-1726 Hz. In the frequency band of 41.5-169.25 Hz for a spectral index of α=0, we constrain the energy density of the stochastic background to be Ω_{GW}(f)<5.6×10^{-6}. For the 600-1000 Hz band, Ω_{GW}(f)<0.14(f/900  Hz)^{3}, a factor of 2.5 lower than the best previously reported upper limits. We find Ω_{GW}(f)<1.8×10^{-4} using a spectral index of zero for 170-600 Hz and Ω_{GW}(f)<1.0(f/1300  Hz)^{3} for 1000-1726 Hz, bands in which no previous direct limits have been placed. The limits in these four bands are the lowest direct measurements to date on the stochastic background. We discuss the implications of these results in light of the recent claim by the BICEP2 experiment of the possible evidence for inflationary gravitational waves.

Death of Darkness: Artificial Sky Brightness in the Anthropocene

NASA Astrophysics Data System (ADS)

Zender, C. S.

2016-12-01

Many species (including ours) need darkness to survive and thrive yet light pollution in the anthropocene has received scant attention in Earth System Models (ESMs). Anthropogenic aerosols can brighten background sky brightness and reduce the contrast between skylight and starlight. These are both aesthetic and health-related issues due to their accompanying disruption of circadian rhythms. We quantify aerosol contributions to light pollution using a single-column night sky model, NiteLite, suitable for implementation in ESMs. NiteLite accounts for physiologcal (photopic and scotopic vision, retinal diameter/age), anthropogenic (light and aerosol pollution properties), and natural (surface albedo, trace gases) effects on background brightness and threshold visibility. We find that stratospheric aerosol injection contemplated as a stop-gap measure to counter global warming would increase night-sky brightness by about 25%, and thus eliminate last pristine dark sky areas on Earth. Our results suggest that ESMs incorporate light pollution so that associated societal impacts can be better quantified and included in policy deliberations.

All-sky brightness monitoring of light pollution with astronomical methods.

PubMed

Rabaza, O; Galadí-Enríquez, D; Estrella, A Espín; Dols, F Aznar

2010-06-01

This paper describes a mobile prototype and a protocol to measure light pollution based on astronomical methods. The prototype takes three all-sky images using BVR filters of the Johnson-Cousins astronomical photometric system. The stars are then identified in the images of the Hipparcos and General Catalogue of Photometric Data II astronomical catalogues, and are used as calibration sources. This method permits the measurement of night-sky brightness and facilitates an estimate of which fraction is due to the light up-scattered in the atmosphere by a wide variety of man-made sources. This is achieved by our software, which compares the sky background flux to that of many stars of known brightness. The reduced weight and dimensions of the prototype allow the user to make measurements from virtually any location. This prototype is capable of measuring the sky distribution of light pollution, and also provides an accurate estimate of the background flux at each photometric band. (c) 2010 Elsevier Ltd. All rights reserved.

Improved detection probability of low level light and infrared image fusion system

NASA Astrophysics Data System (ADS)

Luo, Yuxiang; Fu, Rongguo; Zhang, Junju; Wang, Wencong; Chang, Benkang

2018-02-01

Low level light(LLL) image contains rich information on environment details, but is easily affected by the weather. In the case of smoke, rain, cloud or fog, much target information will lose. Infrared image, which is from the radiation produced by the object itself, can be "active" to obtain the target information in the scene. However, the image contrast and resolution is bad, the ability of the acquisition of target details is very poor, and the imaging mode does not conform to the human visual habit. The fusion of LLL and infrared image can make up for the deficiency of each sensor and give play to the advantages of single sensor. At first, we show the hardware design of fusion circuit. Then, through the recognition probability calculation of the target(one person) and the background image(trees), we find that the trees detection probability of LLL image is higher than that of the infrared image, and the person detection probability of the infrared image is obviously higher than that of LLL image. The detection probability of fusion image for one person and trees is higher than that of single detector. Therefore, image fusion can significantly enlarge recognition probability and improve detection efficiency.

Complete event-by-event α /γ (β ) separation in a full-size TeO2 CUORE bolometer by Neganov-Luke-magnified light detection

NASA Astrophysics Data System (ADS)

Bergé, L.; Chapellier, M.; de Combarieu, M.; Dumoulin, L.; Giuliani, A.; Gros, M.; de Marcillac, P.; Marnieros, S.; Nones, C.; Novati, V.; Olivieri, E.; Paul, B.; Poda, D. V.; Redon, T.; Siebenborn, B.; Zolotarova, A. S.; Armengaud, E.; Augier, C.; Benoît, A.; Billard, J.; Broniatowski, A.; Camus, P.; Cazes, A.; Charlieux, F.; De Jesus, M.; Eitel, K.; Foerster, N.; Gascon, J.; Jin, Y.; Juillard, A.; Kleifges, M.; Kozlov, V.; Kraus, H.; Kudryavtsev, V. A.; Le Sueur, H.; Maisonobe, R.; Navick, X.-F.; Pari, P.; Queguiner, E.; Rozov, S.; Sanglard, V.; Vagneron, L.; Weber, M.; Yakushev, E.

2018-03-01

In the present work, we describe the results obtained with a large (≈133 cm3 ) TeO2 bolometer, with a view to a search for neutrinoless double-β decay (0 ν β β ) of 130Te. We demonstrate an efficient α -particle discrimination (99.9%) with a high acceptance of the 0 ν β β signal (about 96%), expected at ≈2.5 MeV. This unprecedented result was possible thanks to the superior performance (10-eV rms baseline noise) of a Neganov-Luke-assisted germanium bolometer used to detect a tiny (70-eV) light signal from the TeO2 detector, dominated by γ (β )-induced Cherenkov radiation but exhibiting also a clear scintillation component. The obtained results represent a major breakthrough toward the TeO2-based version of the CUORE Upgrade with Particle IDentification (CUPID), a ton-scale cryogenic 0 ν β β experiment proposed as a followup to the Cryogenic Underground Observatory for Rare Events (CUORE) project with particle identification. The CUORE experiment recently began a search for neutrinoless double-β decay of 130Te with an array of 988 125-cm3TeO2 bolometers. The lack of α discrimination in CUORE makes α decays at the detector surface the dominant background component, at the level of ≈0.01 counts/(keV kg y) in the region of interest. We show here, for the first time with a CUORE-size bolometer and using the same technology as CUORE for the readout of both heat and light signals, that surface α background can be fully rejected.

Assessing the effects of architectural variations on light partitioning within virtual wheat–pea mixtures

PubMed Central

Barillot, Romain; Escobar-Gutiérrez, Abraham J.; Fournier, Christian; Huynh, Pierre; Combes, Didier

2014-01-01

Background and Aims Predicting light partitioning in crop mixtures is a critical step in improving the productivity of such complex systems, and light interception has been shown to be closely linked to plant architecture. The aim of the present work was to analyse the relationships between plant architecture and light partitioning within wheat–pea (Triticum aestivum–Pisum sativum) mixtures. An existing model for wheat was utilized and a new model for pea morphogenesis was developed. Both models were then used to assess the effects of architectural variations in light partitioning. Methods First, a deterministic model (L-Pea) was developed in order to obtain dynamic reconstructions of pea architecture. The L-Pea model is based on L-systems formalism and consists of modules for ‘vegetative development’ and ‘organ extension’. A tripartite simulator was then built up from pea and wheat models interfaced with a radiative transfer model. Architectural parameters from both plant models, selected on the basis of their contribution to leaf area index (LAI), height and leaf geometry, were then modified in order to generate contrasting architectures of wheat and pea. Key results By scaling down the analysis to the organ level, it could be shown that the number of branches/tillers and length of internodes significantly determined the partitioning of light within mixtures. Temporal relationships between light partitioning and the LAI and height of the different species showed that light capture was mainly related to the architectural traits involved in plant LAI during the early stages of development, and in plant height during the onset of interspecific competition. Conclusions In silico experiments enabled the study of the intrinsic effects of architectural parameters on the partitioning of light in crop mixtures of wheat and pea. The findings show that plant architecture is an important criterion for the identification/breeding of plant ideotypes, particularly with respect to light partitioning. PMID:24907314

Glueballs on the baryonic branch of Klebanov-Strassler: dimensional deconstruction and a light scalar particle

NASA Astrophysics Data System (ADS)

Elander, Daniel; Piai, Maurizio

2017-06-01

Within gauge/gravity duality, we compute the scalar and tensor mass spectrum in the boundary theory defined by the five-dimensional sigma-model coupled to gravity obtained by constraining to eight scalars the truncation on T 1,1 that corresponds to the Papadopoulos-Tseytlin (PT) ansatz. We study fluctuations around the 1-parameter family of backgrounds that lift to the baryonic branch of the Klebanov-Strassler (KS) system, and interpolates between the KS background and the Maldacena-Nunez one (CVMN). We adopt a gauge invariant formalism in the treatment of the fluctuations that we interpret as states of the dual theory. The tensor spectrum interpolates between the discrete spectrum of the KS background and the continuum spectrum of the CVMN background, in particular showing the emergence of a finite energy range containing a dense set of states, as expected from dimensional deconstruction. The scalar spectrum shows analogous features, and in addition it contains one state that becomes parametrically light far from the origin along the baryonic branch.

Response of Neobenedenia girellae (Monogenea) oncomiracidia to brightness and black-and-white contrast.

PubMed

Ishida, M; Kawano, F; Umeda, N; Hirazawa, N

2007-11-01

Neobenedenia girellae, a capsalid monogenean, is a significant pathogen due to both its ability to cause high mortality in fishes and its low host specificity. Established control methods have both advantages and disadvantages. Biological control measures with no unfavourable effects on the environment should be incorporated into the control strategy. The response of N. girellae oncomiracidia to brightness and black-and-white contrast was investigated to search for an alternative approach of disease prevention or control. Japanese flounder, Paralichthys olivaceus (Paralichthyidae), were exposed to oncomiracidia in an aquarium divided into areas of different brightness ( approximately 1.3, 41.3 and 138.0 lux). The number of parasites on the fish group reared in 138.0 lux was significantly higher than on those reared in the lower brightness levels. Thus, the fish tended to be more vulnerable to infection by N. girellae under brighter conditions. Challenge trials using host fish mucus and whole live fish were established to detect the response by oncomiracidia to black-and-white contrast on a white versus a black background. Markedly more N. girellae oncomiracidia attached to black-painted areas and dark-coloured fish (normal spotted halibut, Verasper variegatus (Pleuronectidae) compared with white-painted areas and light-coloured fish (mal-coloured V. variegatus) on a white-coloured background. On a black-coloured background, more N. girellae oncomiracidia tended to attach to white-painted areas and light-coloured fish. Thus, black-and-white contrast is considered important for host finding by N. girellae oncomiracidia. The simplicity of the positive phototactic behaviour and the response to black-and-white contrast may lead to the development of a simple, practical and inexpensive method to control N. girellae outbreaks.

Transform-limited-pulse representation of excitation with natural incoherent light

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

Chenu, Aurélia, E-mail: aurelia.chenu@utoronto.ca; Brumer, Paul, E-mail: pbrumer@chem.utoronto.ca

2016-01-28

The excitation of molecular systems by natural incoherent light relevant, for example, to photosynthetic light-harvesting is examined. We show that the result of linear excitation with natural incoherent light can be obtained using incident light described in terms of transform limited pulses, as opposed to conventional classical representations with explicit random character. The derived expressions allow for computations to be done directly for any thermal light spectrum using a simple wave function formalism and provide a route to the experimental determination of natural incoherent excitation using pulsed laser techniques. Pulses associated with solar and cosmic microwave background radiation are providedmore » as examples.« less

Minimally invasive surgery: only as good as the picture.

PubMed Central

Drury, Nigel E.; Pollard, Rebecca; Dyer, Jonathan P.

2004-01-01

BACKGROUND: In minimally invasive surgery, there is increased reliance on real-time 2-dimensional images. The fibre-optic light lead is one of the most frequently damaged elements of the 'imaging chain', leading to a poor quality picture. METHODS: Light leads with a honeycomb projection were connected to a light source and the resulting beam directed at a sheet of paper. Darkened sectors with diminished or absent light transmission were recorded. RESULTS: All suitable light leads in routine use were examined. A mean of 22.2% (SD 7.8%) of the projection had diminished or absent light transmission. CONCLUSION: Sub-optimal endoscopic equipment was in routine use. PMID:15005945

Moderated histogram equalization, an automatic means of enhancing the contrast in digital light micrographs reversibly.

PubMed

Entwistle, A

2004-06-01

A means for improving the contrast in the images produced from digital light micrographs is described that requires no intervention by the experimenter: zero-order, scaling, tonally independent, moderated histogram equalization. It is based upon histogram equalization, which often results in digital light micrographs that contain regions that appear to be saturated, negatively biased or very grainy. Here a non-decreasing monotonic function is introduced into the process, which moderates the changes in contrast that are generated. This method is highly effective for all three of the main types of contrast found in digital light micrography: bright objects viewed against a dark background, e.g. fluorescence and dark-ground or dark-field image data sets; bright and dark objects sets against a grey background, e.g. image data sets collected with phase or Nomarski differential interference contrast optics; and darker objects set against a light background, e.g. views of absorbing specimens. Moreover, it is demonstrated that there is a single fixed moderating function, whose actions are independent of the number of elements of image data, which works well with all types of digital light micrographs, including multimodal or multidimensional image data sets. The use of this fixed function is very robust as the appearance of the final image is not altered discernibly when it is applied repeatedly to an image data set. Consequently, moderated histogram equalization can be applied to digital light micrographs as a push-button solution, thereby eliminating biases that those undertaking the processing might have introduced during manual processing. Finally, moderated histogram equalization yields a mapping function and so, through the use of look-up tables, indexes or palettes, the information present in the original data file can be preserved while an image with the improved contrast is displayed on the monitor screen.

Self-organized criticality in a two-dimensional cellular automaton model of a magnetic flux tube with background flow

NASA Astrophysics Data System (ADS)

Dănilă, B.; Harko, T.; Mocanu, G.

2015-11-01

We investigate the transition to self-organized criticality in a two-dimensional model of a flux tube with a background flow. The magnetic induction equation, represented by a partial differential equation with a stochastic source term, is discretized and implemented on a two-dimensional cellular automaton. The energy released by the automaton during one relaxation event is the magnetic energy. As a result of the simulations, we obtain the time evolution of the energy release, of the system control parameter, of the event lifetime distribution and of the event size distribution, respectively, and we establish that a self-organized critical state is indeed reached by the system. Moreover, energetic initial impulses in the magnetohydrodynamic flow can lead to one-dimensional signatures in the magnetic two-dimensional system, once the self-organized critical regime is established. The applications of the model for the study of gamma-ray bursts (GRBs) is briefly considered, and it is shown that some astrophysical parameters of the bursts, like the light curves, the maximum released energy and the number of peaks in the light curve can be reproduced and explained, at least on a qualitative level, by working in a framework in which the systems settles in a self-organized critical state via magnetic reconnection processes in the magnetized GRB fireball.

Role of protein kinase C in light adaptation of molluscan microvillar photoreceptors

PubMed Central

Piccoli, Giuseppe; del Pilar Gomez, Maria; Nasi, Enrico

2002-01-01

The mechanisms by which Ca2+ regulates light adaptation in microvillar photoreceptors remain poorly understood. Protein kinase C (PKC) is a likely candidate, both because some sub-types are activated by Ca2+ and because of its association with the macromolecular ‘light-transduction complex’ in Drosophila. We investigated the possible role of PKC in the modulation of the light response in molluscan photoreceptors. Western blot analysis with isoform-specific antibodies revealed the presence of PKCα in retinal homogenates. Immunocytochemistry in isolated cell preparations confirmed PKCα localization in microvillar photoreceptors, preferentially confined to the light-sensing lobe. Light stimulation induced translocation of PKCα immunofluorescence to the photosensitive membrane, an effect that provides independent evidence for PKC activation by illumination; a similar outcome was observed after incubation with the phorbol ester PMA. Several chemically distinct activators of PKC, such as phorbol-12-myristate-13-acetate (PMA), (-)indolactam V and 1,2,-dioctanoyl-sn-glycerol (DOG) inhibited the light response of voltage-clamped microvillar photoreceptors, but were ineffective in ciliary photoreceptors, in which light does not activate the Gq/PLC cascade, nor elevates intracellular Ca2+. Pharmacological inhibition of PKC antagonized the desensitization produced by adapting lights and also caused a small, but consistent enhancement of basal sensitivity. These results strongly support the involvement of PKC activation in the light-dependent regulation of response sensitivity. However, unlike adapting background light or elevation of [Ca2+]i, PKC activators did not speed up the photoresponse, nor did PKC inhibitors antagonize the accelerating effects of background adaptation, suggesting that modulation of photoresponse time course may involve a separate Ca2+-dependent signal. PMID:12205183

[Evaluation of Sugar Content of Huanghua Pear on Trees by Visible/Near Infrared Spectroscopy].

PubMed

Liu, Hui-jun; Ying, Yi-bin

2015-11-01

A method of ambient light correction was proposed to evaluate the sugar content of Huanghua pears on tree by visible/near infrared diffuse reflectance spectroscopy (Vis/NIRS). Due to strong interference of ambient light, it was difficult to collect the efficient spectral of pears on tree. In the field, covering the fruits with a bag blocking ambient light can get better results, but the efficiency is fairly low, the instrument corrections of dark and reference spectra may help to reduce the error of the model, however, the interference of the ambient light cannot be eliminated effectively. In order to reduce the effect of ambient light, a shutter was attached to the front of probe. When opening shutter, the spot spectrum were obtained, on which instrument light and ambient light acted at the same time. While closing shutter, background spectra were obtained, on which only ambient light acted, then the ambient light spectra was subtracted from spot spectra. Prediction models were built using data on tree (before and after ambient light correction) and after harvesting by partial least square (PLS). The results of the correlation coefficient (R) are 0.1, 0.69, 0.924; the root mean square error of prediction (SEP) are 0. 89°Brix, 0.42°Brix, 0.27°Brix; ratio of standard deviation (SD) to SEP (RPD) are 0.79, 1.69, 2.58, respectively. The results indicate that, method of background correction used in the experiment can reduce the effect of ambient lighting on spectral acquisition of Huanghua pears in field, efficiently. This method can be used to collect the visible/near infrared spectrum of fruits in field, and may give full play to visible/near-infrared spectroscopy in preharvest management and maturity testing of fruits in the field.

Ten-color Gegenschein-zodiacal light photometer. [onboard Skylab

NASA Technical Reports Server (NTRS)

Sparrow, J. G.; Weinberg, J. L.; Hahn, R. C.

1977-01-01

A ten-color Fabry photometer was used during Skylab missions SL-2 and SL-3 to measure sky brightness and polarization associated with zodiacal light, background starlight, F region airglow, and spacecraft corona. A brief description is given of the design, calibration, and performance of the instrument.

The prediction of the optical contrast of air-borne targets against the night-sky background for Photopic and NVG sensors

NASA Astrophysics Data System (ADS)

Havemann, Stephan; Wong, Gerald

2016-10-01

The Havemann-Taylor Fast Radiative Transfer Code (HT-FRTC) represents transmittances, radiances and fluxes by principal components that cover the spectra at very high resolution, allowing fast highly-resolved pseudo line-by-line, hyperspectral and broadband simulations across the electromagnetic spectrum form the microwave to the ultraviolet for satellite-based, airborne and ground-based sensors. HT-FRTC models clear atmospheres and those containing clouds and aerosols, as well as any surface (land/sea/man-made). The HT-FRTC has been used operationally in the NEON Tactical Decision Aid (TDA) since 2008. The TDA combines the HT-FRTC with a thermal contrast model and an NWP model forecast data feed to predict the apparent thermal contrast between different surfaces and ground-based targets in the thermal and short-wave IR. The new objective here is to predict the optical contrast of air-borne targets under realistic night-time scenarios in the Photopic and NVG parts of the spectrum. This requires the inclusion of all the relevant radiation sources, which include twilight, moonlight, starlight, airglow and cultural light. A completely new exact scattering code has been developed which allows the straight-forward addition of any number of direct and diffuse sources anywhere in the atmosphere. The new code solves the radiative transfer equation iteratively and is faster than the previous solution. Simulations of scenarios with different light levels, from situations during a full moon to a moonless night with very low light levels and a situation with cultural light from a town are presented. The impact of surface reflectance and target reflectance is investigated.

Distribution of Organic Carbon in the Sediments of Xinxue River and the Xinxue River Constructed Wetland, China.

PubMed

Cao, Qingqing; Wang, Renqing; Zhang, Haijie; Ge, Xiuli; Liu, Jian

2015-01-01

Wetland ecosystems are represented as a significant reservoir of organic carbon and play an important role in mitigating the greenhouse effect. In order to compare the compositions and distribution of organic carbon in constructed and natural river wetlands, sediments from the Xinxue River Constructed Wetland and the Xinxue River, China, were sampled at two depths (0-15 cm and 15-25 cm) in both upstream and downstream locations. Three types of organic carbon were determined: light fraction organic carbon, heavy fraction organic carbon, and dissolved organic carbon. The results show that variations in light fraction organic carbon are significantly larger between upstream and downstream locations than they are between the two wetland types; however, the opposite trend is observed for the dissolved organic carbon. There are no significant differences in the distribution of heavy fraction organic carbon between the discrete variables (e.g., between the two depths, the two locations, or the two wetland types). However, there are significant cross-variable differences; for example, the distribution patterns of heavy fraction organic carbon between wetland types and depths, and between wetland types and locations. Correlation analysis reveals that light fraction organic carbon is positively associated with light fraction nitrogen in both wetlands, while heavy fraction organic carbon is associated with both heavy fraction nitrogen and the moisture content in the constructed wetland. The results of this study demonstrate that the constructed wetland, which has a relatively low background value of heavy fraction organic carbon, is gradually accumulating organic carbon of different types, with the level of accumulation dependent on the balance between carbon accumulation and carbon decomposition. In contrast, the river wetland has relatively stable levels of organic carbon.

Distribution of Organic Carbon in the Sediments of Xinxue River and the Xinxue River Constructed Wetland, China

PubMed Central

Cao, Qingqing; Wang, Renqing; Zhang, Haijie; Ge, Xiuli; Liu, Jian

2015-01-01

Wetland ecosystems are represented as a significant reservoir of organic carbon and play an important role in mitigating the greenhouse effect. In order to compare the compositions and distribution of organic carbon in constructed and natural river wetlands, sediments from the Xinxue River Constructed Wetland and the Xinxue River, China, were sampled at two depths (0–15 cm and 15–25 cm) in both upstream and downstream locations. Three types of organic carbon were determined: light fraction organic carbon, heavy fraction organic carbon, and dissolved organic carbon. The results show that variations in light fraction organic carbon are significantly larger between upstream and downstream locations than they are between the two wetland types; however, the opposite trend is observed for the dissolved organic carbon. There are no significant differences in the distribution of heavy fraction organic carbon between the discrete variables (e.g., between the two depths, the two locations, or the two wetland types). However, there are significant cross-variable differences; for example, the distribution patterns of heavy fraction organic carbon between wetland types and depths, and between wetland types and locations. Correlation analysis reveals that light fraction organic carbon is positively associated with light fraction nitrogen in both wetlands, while heavy fraction organic carbon is associated with both heavy fraction nitrogen and the moisture content in the constructed wetland. The results of this study demonstrate that the constructed wetland, which has a relatively low background value of heavy fraction organic carbon, is gradually accumulating organic carbon of different types, with the level of accumulation dependent on the balance between carbon accumulation and carbon decomposition. In contrast, the river wetland has relatively stable levels of organic carbon. PMID:26230255

830 nm light-emitting diode low level light therapy (LED-LLLT) enhances wound healing: a preliminary study

PubMed Central

Min, Pok Kee; Goo, Boncheol Leo

2013-01-01

Background and aims: The application of light-emitting diodes in a number of clinical fields is expanding rapidly since the development in the late 1990s of the NASA LED. Wound healing is one field where low level light therapy with LEDs (LED-LLLT) has attracted attention for both accelerating wound healing and controlling sequelae. The present study evaluated LED-LLLT in 5 wounds of various etiologies. Subjects and methods: There were 5 patients with ages ranging from 7 to 54 years, comprising 2 males and 3 females. The study followed 5 wounds, namely 2 acute excoriation wounds; 1 acute/subacute dog bite with infection; 1 subacute post-filler ulcerated wound with necrotic ischemic tissue and secondary infection; and 1 subacute case of edema and infection of the lips with herpes simplex involvement after an illegal cosmetic tattoo operation. All patients were in varying degrees of pain. All wounds were treated with multiple sessions (daily, every other day or twice weekly) using an LED-LLLT system (830 nm, CW, irradiance of 100 mW/cm2 and fluence of 60 J/cm2) till improvement was achieved. Results: Full wound healing and control of infection and discomfort were achieved in all patients, with wound condition-mediated treatment periods ranging from 1 to 8 weeks. No recurrence of the herpes simplex case was seen in a 4-month follow-up. Conclusions: 830 nm LED-LLLT successfully brought about accelerated healing in wounds of different etiologies and at different stages, and successfully controlled secondary infection. LED-LLLT was easy and pain-free to apply, and was well-tolerated by all patients. The good results warrant the design of controlled studies with a larger patient population. PMID:24155549

Effect of morning bright light treatment for rest–activity disruption in institutionalized patients with severe Alzheimer’s disease

PubMed Central

Dowling, Glenna A.; Hubbard, Erin M.; Mastick, Judy; Luxenberg, Jay S.; Burr, Robert L.; Van Someren, Eus J. W.

2008-01-01

Background Disturbances in rest–activity rhythm are prominent and disabling symptoms in Alzheimer’s disease (AD). Nighttime sleep is severely fragmented and daytime activity is disrupted by multiple napping episodes. In most institutional environments, light levels are very low and may not be sufficient to enable the circadian clock to entrain to the 24-hour day. The purpose of this randomized, placebo-controlled, clinical trial was to test the effectiveness of morning bright light therapy in reducing rest–activity (circadian) disruption in institutionalized patients with severe AD. Method Subjects (n = 46, mean age 84 years) meeting the NINCDS-ADRDA (National Institute of Neurological and Communicative Disorders and Stroke –the Alzheimer’s Disease and Related Disorders Association) AD diagnostic criteria were recruited from two large, skilled nursing facilities in San Francisco, California. The experimental group received one hour (09:30–10:30) of bright light exposure (≥ 2500 lux in gaze direction) Monday through Friday for 10 weeks. The control group received usual indoor light (150–200 lux). Nighttime sleep efficiency, sleep time, wake time and number of awakenings and daytime wake time were assessed using actigraphy. Circadian rhythm parameters were also determined from the actigraphic data using cosinor analysis and nonparametric techniques. Repeated measures analysis of variance (ANOVA) was used to test the primary study hypotheses. Results and conclusion Although significant improvements were found in subjects with aberrant timing of their rest–activity rhythm, morning bright light exposure did not induce an overall improvement in measures of sleep or the rest–activity in all treated as compared to control subjects. The results indicate that only subjects with the most impaired rest–activity rhythm respond significantly and positively to a brief (one hour) light intervention. PMID:16050432

Determinants of aerosol lung-deposited surface area variation in an urban environment.

PubMed

Reche, Cristina; Viana, Mar; Brines, Mariola; Pérez, Noemí; Beddows, David; Alastuey, Andrés; Querol, Xavier

2015-06-01

Ultrafine particles are characterized by a high surface area per mass. Particle surface has been reported to play a significant role in determining the toxicological activity of ultrafine particles. In light of this potential role, the time variation of lung deposited surface area (LDSA) concentrations in the alveolar region was studied at the urban background environment of Barcelona (Spain), aiming to asses which processes and sources govern this parameter. Simultaneous data on Black Carbon (BC), total particle number (N) and particle number size distribution were correlated with LDSA. Average LDSA concentrations in Barcelona were 37 ± 26 μm(2)cm(-3), levels which seem to be characteristic for urban environments under traffic influence across Europe. Results confirm the comparability between LDSA data provided by the online monitor and those calculated based on particle size distributions (by SMPS), and reveal that LDSA concentrations are mainly influenced by particles in the size range 50-200 nm. A set of representative daily cycles for LDSA concentrations was obtained by means of a k-means cluster technique. The contribution of traffic emissions to daily patterns was evidenced in all the clusters, but was quantitatively different. Traffic events under stable atmospheric conditions increased mean hourly background LDSA concentrations up to 6 times, attaining levels higher than 200 μm(2)cm(-3). However, under warm and relatively clean atmospheric conditions, the traffic rush hour contribution to the daily LDSA mean appeared to be lower and the contribution of new urban particle formation events (by photochemically induced nucleation) was detected. These nucleation events were calculated to increase average background LDSA concentrations by 15-35% (maximum LDSA levels=45-50 μm(2)cm(-3)). Thereby, it may be concluded that in the urban background of Barcelona road traffic is the main source increasing the aerosol surface area which can deposit on critical regions of the human lung, followed by nucleation episodes. Copyright © 2015 Elsevier B.V. All rights reserved.

Portable sample preparation and analysis system for micron and sub-micron particle characterization using light scattering and absorption spectroscopy

DOEpatents

Stark, Peter C [Los Alamos, NM; Zurek, Eduardo [Barranquilla, CO; Wheat, Jeffrey V [Fort Walton Beach, FL; Dunbar, John M [Santa Fe, NM; Olivares, Jose A [Los Alamos, NM; Garcia-Rubio, Luis H [Temple Terrace, FL; Ward, Michael D [Los Alamos, NM

2011-07-26

There is provided a method and device for remote sampling, preparation and optical interrogation of a sample using light scattering and light absorption methods. The portable device is a filtration-based device that removes interfering background particle material from the sample matrix by segregating or filtering the chosen analyte from the sample solution or matrix while allowing the interfering background particles to be pumped out of the device. The segregated analyte is then suspended in a diluent for analysis. The device is capable of calculating an initial concentration of the analyte, as well as diluting the analyte such that reliable optical measurements can be made. Suitable analytes include cells, microorganisms, bioparticles, pathogens and diseases. Sample matrixes include biological fluids such as blood and urine, as well as environmental samples including waste water.

Light scalars on cosmological backgrounds

NASA Astrophysics Data System (ADS)

Markkanen, Tommi

2018-01-01

We study the behaviour of a light quartically self-interacting scalar field ϕ on curved backgrounds that may be described with the cosmological equation state parameter w. At leading order in the non-perturbative 2PI expansion we find a general formula for the variance < {\\widehat{φ}}^2> and show for several previously unexplored cases, including matter domination and kination, that the curvature of space can induce a significant excitation of the field. We discuss how the generation of a non-zero variance for w ≠ -1 can be understood as a process of self-regulation of the infrared divergences very similarly to what is known to occur in de Sitter space. To conclude, the appearance of an effective mass due to self-interaction is generic for a light scalar in curved space and can have important implications for reheating, vacuum stability and dark matter generation.

How Does Circadian Rhythm Impact Salt Sensitivity of Blood Pressure in Mice? A Study in Two Close C57Bl/6 Substrains.

PubMed

Combe, Roy; Mudgett, John; El Fertak, Lahcen; Champy, Marie-France; Ayme-Dietrich, Estelle; Petit-Demoulière, Benoit; Sorg, Tania; Herault, Yann; Madwed, Jeffrey B; Monassier, Laurent

2016-01-01

Mouse transgenesis has provided the unique opportunity to investigate mechanisms underlying sodium kidney reabsorption as well as end organ damage. However, understanding mouse background and the experimental conditions effects on phenotypic readouts of engineered mouse lines such as blood pressure presents a challenge. Despite the ability to generate high sodium and chloride plasma levels during high-salt diet, observed changes in blood pressure are not consistent between wild-type background strains and studies. The present work was designed in an attempt to determine guidelines in the field of salt-induced hypertension by recording continuously blood pressure by telemetry in mice submitted to different sodium and potassium loaded diets and changing experimental conditions in both C57BL/6N and C57BL/6J mice strain (Normal salt vs. Low salt vs. High-salt/normal potassium vs. High salt/low potassium, standard vs. modified light cycle, Non-invasive tail cuff blood pressure vs. telemetry). In this study, we have shown that, despite a strong blood pressure (BP) basal difference between C57BL/6N and C57BL/6J mice, High salt/normal potassium diet increases BP and heart rate during the active phase only (dark period) in the same extent in both strains. On the other hand, while potassium level has no effect on salt-induced hypertension in C57BL/6N mice, high-salt/low potassium diet amplifies the effect of the high-salt challenge only in C57BL/6J mice. Indeed, in this condition, salt-induced hypertension can also be detected during light period even though this BP increase is lower compared to the one occurring during the dark period. Finally, from a methodological perspective, light cycle inversion has no effect on this circadian BP phenotype and tail-cuff method is less sensitive than telemetry to detect BP phenotypes due to salt challenges. Therefore, to carry investigations on salt-induced hypertension in mice, chronic telemetry and studies in the active phase are essential prerequisites.

Low-level mitochondrial heteroplasmy modulates DNA replication, glucose metabolism and lifespan in mice.

PubMed

Hirose, Misa; Schilf, Paul; Gupta, Yask; Zarse, Kim; Künstner, Axel; Fähnrich, Anke; Busch, Hauke; Yin, Junping; Wright, Marvin N; Ziegler, Andreas; Vallier, Marie; Belheouane, Meriem; Baines, John F; Tautz, Diethard; Johann, Kornelia; Oelkrug, Rebecca; Mittag, Jens; Lehnert, Hendrik; Othman, Alaa; Jöhren, Olaf; Schwaninger, Markus; Prehn, Cornelia; Adamski, Jerzy; Shima, Kensuke; Rupp, Jan; Häsler, Robert; Fuellen, Georg; Köhling, Rüdiger; Ristow, Michael; Ibrahim, Saleh M

2018-04-12

Mutations in mitochondrial DNA (mtDNA) lead to heteroplasmy, i.e., the intracellular coexistence of wild-type and mutant mtDNA strands, which impact a wide spectrum of diseases but also physiological processes, including endurance exercise performance in athletes. However, the phenotypic consequences of limited levels of naturally arising heteroplasmy have not been experimentally studied to date. We hence generated a conplastic mouse strain carrying the mitochondrial genome of an AKR/J mouse strain (B6-mt AKR ) in a C57BL/6 J nuclear genomic background, leading to >20% heteroplasmy in the origin of light-strand DNA replication (OriL). These conplastic mice demonstrate a shorter lifespan as well as dysregulation of multiple metabolic pathways, culminating in impaired glucose metabolism, compared to that of wild-type C57BL/6 J mice carrying lower levels of heteroplasmy. Our results indicate that physiologically relevant differences in mtDNA heteroplasmy levels at a single, functionally important site impair the metabolic health and lifespan in mice.

Scanning thin-sheet laser imaging microscopy (sTSLIM) with structured illumination and HiLo background rejection.

PubMed Central

Schröter, Tobias J.; Johnson, Shane B.; John, Kerstin; Santi, Peter A.

2011-01-01

We report replacement of one side of a static illumination, dual sided, thin-sheet laser imaging microscope (TSLIM) with an intensity modulated laser scanner in order to implement structured illumination (SI) and HiLo image demodulation techniques for background rejection. The new system is equipped with one static and one scanned light-sheet and is called a scanning thin-sheet laser imaging microscope (sTSLIM). It is an optimized version of a light-sheet fluorescent microscope that is designed to image large specimens (<15 mm in diameter). In this paper we describe the hardware and software modifications to TSLIM that allow for static and uniform light-sheet illumination with SI and HiLo image demodulation. The static light-sheet has a thickness of 3.2 µm; whereas, the scanned side has a light-sheet thickness of 4.2 µm. The scanned side images specimens with subcellular resolution (<1 µm lateral and <4 µm axial resolution) with a size up to 15 mm. SI and HiLo produce superior contrast compared to both the uniform static and scanned light-sheets. HiLo contrast was greater than SI and is faster and more robust than SI because as it produces images in two-thirds of the time and exhibits fewer intensity streaking artifacts. PMID:22254177

Design principles of the LVT-2 model laser instrument for the measurement of visual characteristics

NASA Astrophysics Data System (ADS)

Sun, Wende

1989-10-01

As far as the LVT-2 model laser visual acuity measuring instrument, after its model improvement, is concerned, it not only is capable of measuring the visual acuity of retina (LVA), but also capable of measuring the MTF of retina. The light path system of the instrument has three sections. One is a double light bundle common path interference system making use of double Dufu prisms to divide bundles. In conjunction with this, it uses the movement of a reflection lens M2 in order to change the interval distance of the two mutually interfering bundles. As a result of this, it changes the spacial frequency of the interference bands. This acts as the light path to measure LVA. The second is the background light set composed of such components as the tungsten filament lamp T sub L, the interference filter optical plate OF, and the polarization lens P2. It is used in order to form, on the retina, a uniform background base light. In conjunction with this, through adjustments of the dispersion prism B in the light path, adjustments are made in the degree of contrast change I sub O/I sub u measuring the MTF of the retina.

A Novel Approach to model EPIC variable background

NASA Astrophysics Data System (ADS)

Marelli, M.; De Luca, A.; Salvetti, D.; Belfiore, A.

2017-10-01

One of the main aim of the EXTraS (Exploring the X-ray Transient and variable Sky) project is to characterise the variability of serendipitous XMM-Newton sources within each single observation. Unfortunately, 164 Ms out of the 774 Ms of cumulative exposure considered (21%) are badly affected by soft proton flares, hampering any classical analysis of field sources. De facto, the latest releases of the 3XMM catalog, as well as most of the analysis in literature, simply exclude these 'high background' periods from analysis. We implemented a novel SAS-indipendent approach to produce background-subtracted light curves, which allows to treat the case of very faint sources and very bright proton flares. EXTraS light curves of 3XMM-DR5 sources will be soon released to the community, together with new tools we are developing.

Virasoro conformal blocks and thermality from classical background fields

DOE PAGES

Fitzpatrick, A. Liam; Kaplan, Jared; Walters, Matthew T.

2015-11-30

We show that in 2d CFTs at large central charge, the coupling of the stress tensor to heavy operators can be re-absorbed by placing the CFT in a non-trivial background metric. This leads to a more precise computation of the Virasoro conformal blocks between heavy and light operators, which are shown to be equivalent to global conformal blocks evaluated in the new background. We also generalize to the case where the operators carry U(1) charges. The refined Virasoro blocks can be used as the seed for a new Virasoro block recursion relation expanded in the heavy-light limit. Furthermore, we commentmore » on the implications of our results for the universality of black hole thermality in AdS 3 , or equivalently, the eigenstate thermalization hypothesis for CFT 2 at large central charge.« less

16 CFR § 1404.2 - Background.

Code of Federal Regulations, 2013 CFR

2013-01-01

... INSULATION § 1404.2 Background. Based on available fire incident information, engineering analysis of the... fires can occur where cellulose insulation is improperly installed too close to the sides or over the top of recessed electrical light fixtures, or installed too close to the exhaust flues from heat...

Assembling the Infrared Extragalactic Background Light with CIBER-2: Probing Inter-Halo Light and the Epoch of Reionization.

NASA Astrophysics Data System (ADS)

Bock, James

We propose to carry out a program of observations with the Cosmic Infrared Background Experiment (CIBER-2). CIBER-2 is a near-infrared sounding rocket experiment designed to measure spatial fluctuations in the extragalactic background light. CIBER-2 scientifically follows on the detection of fluctuations with the CIBER-1 imaging instrument, and will use measurement techniques developed and successfully demonstrated by CIBER-1. With high-sensitivity, multi-band imaging measurements, CIBER-2 will elucidate the history of interhalo light (IHL) production and carry out a deep search for extragalactic background fluctuations associated with the epoch of reionization (EOR). CIBER-1 has made high-quality detections of large-scale fluctuations over 4 sounding rocket flights. CIBER-1 measured the amplitude and spatial power spectrum of fluctuations, and observed an electromagnetic spectrum that is close to Rayleigh-Jeans, but with a statistically significant turnover at 1.1 um. The fluctuations cross-correlate with Spitzer images and are significantly bluer than the spectrum of the integrated background derived from galaxy counts. We interpret the CIBER-1 fluctuations as arising from IHL, low-mass stars tidally stripped from their parent galaxies during galaxy mergers. The first generation of stars and their remnants are likely responsible for the for the reionization of the intergalactic medium, observed to be ionized out to the most distant quasars at a redshift of 6. The total luminosity produced by first stars is uncertain, but a lower limit can be placed assuming a minimal number of photons to produce and sustain reionization. This 'minimal' extragalactic background component associated with reionization is detectable in fluctuations at the design sensitivity of CIBER-2. The CIBER-2 instrument is optimized for sensitivity to surface brightness in a short sounding rocket flight. The instrument consists of a 28 cm wide-field telescope operating in 6 spectral bands between 0.5 and 2.0 um, cooled to a temperature of 77 K with a liquid nitrogen cryostat. Images are composed using 3 focal plane assemblies operating H2RG detector arrays. The instrument is currently being fabricated with expected delivery during summer 2014, and will be ready for its first flight in 2015. CIBER-2 will extend the CIBER-1 observations from the near-infrared into the optical, where the EOR and IHL components of the extragalactic background can be cleanly distinguished and separated. We will study the history of IHL production by implementing a multi-band cross-correlation analysis, and use this information to carry out a deep search for an EOR component. In subsequent flights we plan joint observations with weak lensing maps, with an optimized set of filter bands to measure spectral cross-correlations, to fully elucidate the history of IHL light production.

Fluorescence spectroscopy of trapped molecular ions

NASA Astrophysics Data System (ADS)

Wright, Kenneth Charles

This thesis describes the development of a unique instrument capable of detecting fluorescence emission from large gas phase molecular ions trapped in a three-dimensional quadrupole ion trap. The hypothesis that has formed the basis of this work is the belief that fluorescence spectroscopy can be combined with ion trap mass spectrometry to probe the structure of gas phase molecular ions. The ion trap provides a rarefied environment where fluorescence experiments can be conducted without interference from solvent molecules or impurities. Although fluorescence was not detected during preliminary experiments, two significant experimental challenges associated with detecting the gas phase fluorescence of ions were discovered. First, gas phase ions were vulnerable to photodissociation and low laser powers were necessary to avoid photodissociation. Since fluorescence emission is directly proportional to laser intensity, a lower laser power limits the fluorescence signal. Second, the fluorescence emission was not significantly Stokes shifted from the excitation. The lack of Stokes shift meant the small fluorescence signal must be detected in the presence of a large amount of background scatter generated by the excitation. Initially, this background was seven orders of magnitude higher than the analytical signal ultimately detected. A specially designed fiber optic probe was inserted between the electrodes of the ion trap to stop light scattered off the outside surfaces of the trap from reaching the detector. The inside surfaces of the ion trap were coated black to further reduce the amount of scattered light collected. These innovations helped reduced the background by six orders of magnitude and fluorescence emission from rhodamine-6G was detected. Pulse counting experiments were used to optimize fluorescence detection. The effects of trapping level, laser power, and irradiation time were investigated and optimized. The instrument developed in this work not only allows for the detection of fluorescent photons, but the sensitivity is high enough for the light to be dispersed and an emission spectrum recorded. The emission spectra of rhodamine-6G and 5-carboxyrhodamine-6G ions reported in this thesis represent the first spectra recorded from large molecular ions confined in a quadrupole ion trap. Finally, anti-Stokes fluorescence from rhodamine-6G was also detected.

Thin laser light sheet microscope for microbial oceanography

NASA Astrophysics Data System (ADS)

Fuchs, Eran; Jaffe, Jules S.; Long, Richard A.; Azam, Farooq

2002-01-01

Despite a growing need, oceanographers are limited by existing technological constrains and are unable to observe aquatic microbes in their natural setting. In order to provide a simple and easy to implement solution for such studies, a new Thin Light Sheet Microscope (TLSM) has been developed. The TLSM utilizes a well-defined sheet of laser light, which has a narrow (23 micron) axial dimension over a 1 mm x 1 mm field of view. This light sheet is positioned precisely within the depth of field of the microscope’s objective lens. The technique thus utilizes conventional microscope optics but replaces the illumination system. The advantages of the TLSM are two-fold: First, it concentrates light only where excitation is needed, thus maximizing the efficiency of the illumination source. Secondly, the TLSM maximizes image sharpness while at the same time minimizing the level of background noise. Particles that are not located within the objective's depth of field are not illuminated and therefore do not contribute to an out-of-focus image. Images from a prototype system that used SYBR Green I fluorescence stain in order to localize single bacteria are reported. The bacteria were in a relatively large and undisturbed volume of 4ml, which contained natural seawater. The TLSM can be used for fresh water studies of bacteria with no modification. The microscope permits the observation of interactions at the microscale and has potential to yield insights into how microbes structure pelagic ecosystems.

Free kappa light chains in cerebrospinal fluid as a biomarker to assess risk conversion to multiple sclerosis

PubMed Central

Menéndez-Valladares, P; García-Sánchez, MI; Cuadri Benítez, P; Lucas, M; Adorna Martínez, M; Carranco Galán, V; García De Veas Silva, JL; Bermudo Guitarte, C

2015-01-01

Background Multiple sclerosis (MS) initiates with a first attack or clinically isolated syndrome (CIS). The importance of an early treatment in MS leads to the search, as soon as possible, for novel biomarkers which can predict conversion from CIS to MS. Objective The purpose of this study was to assess the predictive value of the kappa index (κ index), using kappa free light light chains (κFLCs) in cerebrospinal fluid (CSF), for the conversion of CIS patients to MS, and compare its accuracy with other parameters used in clinical practice. Methods FLC levels were analysed in CSF from 176 patients: 70 as control group, 77 CIS, and 29 relapsing–remitting MS. FLC levels were quantified by nephelometry. Results κ Index sensitivity and specificity (93.1%; 95.7%) was higher than those from the immunoglobulin G (IgG) index (75.9%; 94.3%), and lower than those from oligoclonal IgG bands (OCGBs) (96.5%; 98.6%). The optimal cut-off for κ index was 10.62. Most of the CIS patients with κ index >10.62 presented OCGBs, IgG index >0.56 and fulfilled magnetic resonance imaging (MRI) criteria. Conclusion CIS patients above κ index cut-off of 10.62 present 7.34-fold risk of conversion to MS than CIS below this value. The κ index correlated with positive OCGBs, IgG index above 0.56 and MRI criteria. PMID:28607709

Programmable spectral engine design of hyperspectral image projectors based on digital micro-mirror device (DMD)

NASA Astrophysics Data System (ADS)

Wang, Xicheng; Gao, Jiaobo; Wu, Jianghui; Li, Jianjun; Cheng, Hongliang

2017-02-01

Recently, hyperspectral image projectors (HIP) have been developed in the field of remote sensing. For the advanced performance of system-level validation, target detection and hyperspectral image calibration, HIP has great possibility of development in military, medicine, commercial and so on. HIP is based on the digital micro-mirror device (DMD) and projection technology, which is capable to project arbitrary programmable spectra (controlled by PC) into the each pixel of the IUT1 (instrument under test), such that the projected image could simulate realistic scenes that hyperspectral image could be measured during its use and enable system-level performance testing and validation. In this paper, we built a visible hyperspectral image projector also called the visible target simulator with double DMDs, which the first DMD is used to product the selected monochromatic light from the wavelength of 410 to 720 um, and the light come to the other one. Then we use computer to load image of realistic scenes to the second DMD, so that the target condition and background could be project by the second DMD with the selected monochromatic light. The target condition can be simulated and the experiment could be controlled and repeated in the lab, making the detector instrument could be tested in the lab. For the moment, we make the focus on the spectral engine design include the optical system, research of DMD programmable spectrum and the spectral resolution of the selected spectrum. The detail is shown.

Particulate matter (PM) concentrations in underground and ground-level rail systems of the Los Angeles Metro

NASA Astrophysics Data System (ADS)

Kam, Winnie; Cheung, Kalam; Daher, Nancy; Sioutas, Constantinos

2011-03-01

Elevated concentrations of particulate matter (PM) have been found in a number of worldwide underground transit systems, with major implications regarding exposure of commuters to PM and its associated health effects. An extensive sampling campaign was conducted in May-August 2010 to measure PM concentrations in two lines of the Los Angeles Metro system - an underground subway line (Metro red line) and a ground-level light-rail line (Metro gold line). The campaign goals were to: 1) determine personal PM exposure of commuters of both lines, and 2) measure and compare PM concentrations at station platforms and inside the train. Considering that a commuter typically spent 75% of time inside the train and 25% of time waiting at a station, subway commuters were exposed on average to PM 10 and PM 2.5 concentrations that were 1.9 and 1.8 times greater than the light-rail commuters. The average PM 10 concentrations for the subway line at station platforms and inside the train were 78.0 μg m -3 and 31.5 μg m -3, respectively; for the light-rail line, corresponding PM 10 concentrations were 38.2 μg m -3 and 16.2 μg m -3. Regression analysis demonstrated that personal exposure concentrations for the light-rail line are strongly associated with ambient PM levels ( R2 = 0.61), while PM concentrations for the subway line are less influenced by ambient conditions ( R2 = 0.38) and have a relatively stable background level of about 21 μg m -3. Our findings suggest that local emissions (i.e., vehicular traffic, road dust) are the main source of airborne PM for the light-rail line. The subway line, on the other hand, has an additional source of PM, most likely generated from the daily operation of trains. Strong inter-correlation of PM 10 between the train and station microenvironments shows that airborne PM at stations are the main source of PM inside the trains for both lines ( R2 = 0.91 and 0.81 for subway and light-rail line, respectively). In addition, PM 2.5 and coarse PM (PM 10-2.5) are also strongly correlated for the subway line ( R2 = 0.89) and the light-rail line ( R2 = 0.52-0.92), suggesting that PM 2.5 and coarse PM originate from a common source. Finally, in comparison to worldwide subway systems, the L.A. Metro system is relatively 'clean'. Since the system is comparatively new (in operation since 1993), its ventilation system and braking technology are probably more efficient and more advanced than older subway systems.

[The Performance Analysis for Lighting Sources in Highway Tunnel Based on Visual Function].

PubMed

Yang, Yong; Han, Wen-yuan; Yan, Ming; Jiang, Hai-feng; Zhu, Li-wei

2015-10-01

Under the condition of mesopic vision, the spectral luminous efficiency function is shown as a series of curves. Its peak wavelength and intensity are affected by light spectrum, background brightness and other aspects. The impact of light source to lighting visibility could not be carried out via a single optical parametric characterization. The reaction time of visual cognition is regard as evaluating indexes in this experiment. Under the condition of different speed and luminous environment, testing visual cognition based on vision function method. The light sources include high pressure sodium, electrodeless fluorescent lamp and white LED with three kinds of color temperature (the range of color temperature is from 1 958 to 5 537 K). The background brightness value is used for basic section of highway tunnel illumination and general outdoor illumination, its range is between 1 and 5 cd x m(-)2. All values are in the scope of mesopic vision. Test results show that: under the same condition of speed and luminance, the reaction time of visual cognition that corresponding to high color temperature of light source is shorter than it corresponding to low color temperature; the reaction time corresponding to visual target in high speed is shorter than it in low speed. At the end moment, however, the visual angle of target in observer's visual field that corresponding to low speed was larger than it corresponding to high speed. Based on MOVE model, calculating the equivalent luminance of human mesopic vision, which is on condition of different emission spectrum and background brightness that formed by test lighting sources. Compared with photopic vision result, the standard deviation (CV) of time-reaction curve corresponding to equivalent brightness of mesopic vision is smaller. Under the condition of mesopic vision, the discrepancy between equivalent brightness of different lighting source and photopic vision, that is one of the main reasons for causing the discrepancy of visual recognition. The emission spectrum peak of GaN chip is approximate to the wave length peak of efficiency function in photopic vision. The lighting visual effect of write LED in high color temperature is better than it in low color temperature and electrodeless fluorescent lamp. The lighting visual effect of high pressure sodium is weak. Because of its peak value is around the Na+ characteristic spectra.

Effect of luminosity on color discrimination of dichromatic marmosets (Callithrix jacchus).

PubMed

Freitag, Fabio Batista; Pessoa, Daniel Marques Almeida

2012-02-01

Psychophysical data have shown that under mesopic conditions cones and rods can interact, improving color vision. Since electrophysiological data have suggested that rods of dichromatic marmosets appear to be active at higher luminance, we aimed to investigate the effect of different levels of sunlight on the foraging abilities of male dichromatic marmosets. Captive marmosets were observed under three different conditions, with respect to their performance in detecting colored food items against a green background. Compared to high and low light intensities, intermediate luminosities significantly increased detection of orange targets by male dichromats, an indication of rod intrusion. © 2012 Optical Society of America

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

Daniel, Scott F.; Linder, Eric V.; Lawrence Berkeley National Laboratory, Berkeley, California

Deviations from general relativity, such as could be responsible for the cosmic acceleration, would influence the growth of large-scale structure and the deflection of light by that structure. We clarify the relations between several different model-independent approaches to deviations from general relativity appearing in the literature, devising a translation table. We examine current constraints on such deviations, using weak gravitational lensing data of the CFHTLS and COSMOS surveys, cosmic microwave background radiation data of WMAP5, and supernova distance data of Union2. A Markov chain Monte Carlo likelihood analysis of the parameters over various redshift ranges yields consistency with general relativitymore » at the 95% confidence level.« less

Cosmic PeV neutrinos and the sources of ultrahigh energy protons

NASA Astrophysics Data System (ADS)

Kistler, Matthew D.; Stanev, Todor; Yüksel, Hasan

2014-12-01

The IceCube experiment recently detected the first flux of high-energy neutrinos in excess of atmospheric backgrounds. We examine whether these neutrinos originate from within the same extragalactic sources as ultrahigh energy cosmic rays. Starting from rather general assumptions about spectra and flavors, we find that producing a neutrino flux at the requisite level through pion photoproduction leads to a flux of protons well below the cosmic-ray data at ˜1 018 eV , where the composition is light, unless pions/muons cool before decaying. This suggests a dominant class of accelerator that allows for cosmic rays to escape without significant neutrino yields.

Effect of boron doping on first-order Raman scattering in superconducting boron doped diamond films

NASA Astrophysics Data System (ADS)

Kumar, Dinesh; Chandran, Maneesh; Ramachandra Rao, M. S.

2017-05-01

Aggregation of impurity levels into an impurity band in heavily boron doped diamond results in a background continuum and discrete zone centre phonon interference during the inelastic light scattering process. In order to understand the Raman scattering effect in granular BDD films, systematically heavily doped samples in the semiconducting and superconducting regimes have been studied using the excitation wavelengths in the UV and visible regions. A comprehensive analysis of the Fano resonance effect as a function of the impurity concentrations and the excitation frequencies is presented. Various Raman modes available in BDD including signals from the grain boundaries are discussed.

Perspective: Biotech funding trends: Insights from entrepreneurs and investors.

PubMed

Gruber, Alexandra C

2009-08-01

Based on a qualitative study analyzing a series of interviews with dedicated biotech entrepreneurs and high-level investors, "Biotech Funding Trends" provides a comprehensive overview of current trends in biotech funding by taking a close look behind the scenes of the biotech industry. In particular, it illustrates the tensions between both key players based on their different backgrounds and expectations. Here we outline the various funding opportunities for the biotech industry in Europe and identify ways for both sides, entrepreneurs and investors to overcome their prejudices to successfully thrive in a competitive environment. The results are also discussed in the light of the current financial and economic crisis.

Light Scattering by Polymers: Two Experiments for Advanced Undergraduates.

ERIC Educational Resources Information Center

Matthews, G. P.

1984-01-01

Background information, procedures, equipment, and results for two experiments are presented. The first involves the measurement of the mass-average and degree of coiling of polystyrene and is interpreted by the full mathematical theory of light scattering. The second is the study of transitions in gelatin. (JN)

Measurements of SWIR backgrounds using the swux unit of measure

NASA Astrophysics Data System (ADS)

Richards, A.; Hübner, M.; Vollmer, M.

2018-04-01

The SWIR waveband between 0.8μm-1.8μm is getting increasingly exploited by imaging systems in a variety of different applications, including persistent imaging for security and surveillance of high-value assets, handheld tactical imagers, range-gated imaging systems and imaging LADAR for driverless vehicles. The vast majority of these applications utilize lattice-matched InGaAs detectors in their imaging sensors, and these sensors are rapidly falling in price, leading to their widening adoption. As these sensors are used in novel applications and locations, it is important that ambient SWIR backgrounds be understood and characterized for a variety of different field conditions, primarily for the purposes of system performance modeling of SNR and range metrics. SWIR irradiance backgrounds do not consistently track visible-light illumination at all. There is currently little of this type of information in the open literature, particularly measurements of SWIR backgrounds in urban areas, natural areas, or indoors. This paper presents field measurements done with an InGaAs detector calibrated in the swux unit of InGaAs-band-specific irradiance proposed by two of the authors in 2017. Simultaneous measurements of illuminance levels (in lux) at these sites are presented, as well as visible and InGaAs camera images of the scenery at some of these measurement sites. The swux and lux measurement hardware is described, along with the methods used to calibrate it. Finally, the swux levels during the partial and total phases of the total solar eclipse of 2017 are presented, along with curves fitted to the data from a theoretical model, based on obscuration of the sun by the moon. The apparent differences between photometric and swux measurements will be discussed.

Optimizing countershading camouflage.

PubMed

Cuthill, Innes C; Sanghera, N Simon; Penacchio, Olivier; Lovell, Paul George; Ruxton, Graeme D; Harris, Julie M

2016-11-15

Countershading, the widespread tendency of animals to be darker on the side that receives strongest illumination, has classically been explained as an adaptation for camouflage: obliterating cues to 3D shape and enhancing background matching. However, there have only been two quantitative tests of whether the patterns observed in different species match the optimal shading to obliterate 3D cues, and no tests of whether optimal countershading actually improves concealment or survival. We use a mathematical model of the light field to predict the optimal countershading for concealment that is specific to the light environment and then test this prediction with correspondingly patterned model "caterpillars" exposed to avian predation in the field. We show that the optimal countershading is strongly illumination-dependent. A relatively sharp transition in surface patterning from dark to light is only optimal under direct solar illumination; if there is diffuse illumination from cloudy skies or shade, the pattern provides no advantage over homogeneous background-matching coloration. Conversely, a smoother gradation between dark and light is optimal under cloudy skies or shade. The demonstration of these illumination-dependent effects of different countershading patterns on predation risk strongly supports the comparative evidence showing that the type of countershading varies with light environment.

Chromatic illumination discrimination ability reveals that human colour constancy is optimised for blue daylight illuminations.

PubMed

Pearce, Bradley; Crichton, Stuart; Mackiewicz, Michal; Finlayson, Graham D; Hurlbert, Anya

2014-01-01

The phenomenon of colour constancy in human visual perception keeps surface colours constant, despite changes in their reflected light due to changing illumination. Although colour constancy has evolved under a constrained subset of illuminations, it is unknown whether its underlying mechanisms, thought to involve multiple components from retina to cortex, are optimised for particular environmental variations. Here we demonstrate a new method for investigating colour constancy using illumination matching in real scenes which, unlike previous methods using surface matching and simulated scenes, allows testing of multiple, real illuminations. We use real scenes consisting of solid familiar or unfamiliar objects against uniform or variegated backgrounds and compare discrimination performance for typical illuminations from the daylight chromaticity locus (approximately blue-yellow) and atypical spectra from an orthogonal locus (approximately red-green, at correlated colour temperature 6700 K), all produced in real time by a 10-channel LED illuminator. We find that discrimination of illumination changes is poorer along the daylight locus than the atypical locus, and is poorest particularly for bluer illumination changes, demonstrating conversely that surface colour constancy is best for blue daylight illuminations. Illumination discrimination is also enhanced, and therefore colour constancy diminished, for uniform backgrounds, irrespective of the object type. These results are not explained by statistical properties of the scene signal changes at the retinal level. We conclude that high-level mechanisms of colour constancy are biased for the blue daylight illuminations and variegated backgrounds to which the human visual system has typically been exposed.

22 CFR 42.33 - Diversity immigrants.

Code of Federal Regulations, 2011 CFR

2011-04-01

...-line and submit to the Department of State via a Web site established by the Department of State for the purpose of receiving such petitions. The Department will specify the address of the Web site prior... neutral, light-colored background. Photos taken with very dark or patterned, busy backgrounds will not be...

22 CFR 42.33 - Diversity immigrants.

Code of Federal Regulations, 2012 CFR

2012-04-01

...-line and submit to the Department of State via a Web site established by the Department of State for the purpose of receiving such petitions. The Department will specify the address of the Web site prior... neutral, light-colored background. Photos taken with very dark or patterned, busy backgrounds will not be...

22 CFR 42.33 - Diversity immigrants.

Code of Federal Regulations, 2013 CFR

2013-04-01

...-line and submit to the Department of State via a Web site established by the Department of State for the purpose of receiving such petitions. The Department will specify the address of the Web site prior... neutral, light-colored background. Photos taken with very dark or patterned, busy backgrounds will not be...

22 CFR 42.33 - Diversity immigrants.

Code of Federal Regulations, 2010 CFR

2010-04-01

...-line and submit to the Department of State via a Web site established by the Department of State for the purpose of receiving such petitions. The Department will specify the address of the Web site prior... neutral, light-colored background. Photos taken with very dark or patterned, busy backgrounds will not be...

22 CFR 42.33 - Diversity immigrants.

Code of Federal Regulations, 2014 CFR

2014-04-01

...-line and submit to the Department of State via a Web site established by the Department of State for the purpose of receiving such petitions. The Department will specify the address of the Web site prior... neutral, light-colored background. Photos taken with very dark or patterned, busy backgrounds will not be...

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

PubMed

Versteeg, Ruth I; Stenvers, Dirk J; Visintainer, Dana; Linnenbank, Andre; Tanck, Michael W; Zwanenburg, Gooitzen; Smilde, Age K; Fliers, Eric; Kalsbeek, Andries; Serlie, Mireille J; la Fleur, Susanne E; Bisschop, Peter H

2017-04-01

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

Thoron (220Rn) in the indoor environment and work places

NASA Astrophysics Data System (ADS)

Ramachandran, T. V.; Sahoo, B. K.

2009-08-01

Ever since studies on uranium miners established the presence of a positive risk coefficient for the occurrence of lung cancer in miners exposed to elevated levels of 222Rn and its progeny, there was a great upsurge of interest in the measurement of 222Rn in the environment. Subsequently, considerable data is being generated on the levels of 222Rn in the environment across the worlds and is being periodically reported by UNSCEAR reports. In contrast to this, data pertaining to 220Rn in indoors and workplace environment is scaree due to the genral perception that its levels are negligible due to its shorter half life, and subsequently its contribution to the total inhalation dose is ignored, in the presence of other significant sources of natural radiation. This may not be true. Globally many locations have higher levels of natural background radiation due to elevated levels of primordial radio nuclides in the soil and their decay products like radon (222Rn), and thoron (220Rn) in the environment. Of late, technologically enhanced naturally occurring radioactive material has also contributed to the burden of background radiation. It is estimated that inhalation of 222Rn, 220Rn and their short lived progenies contribute more than 54% of the total natural background radiation dose received by the general population. 220Rn problem exists in industries which use thorium nitrate. Including India, lamps using thoriated gas mantles are still being used for indoor and outdoor lighting and by hawkers in rural as well as urban areas. Considering the fact that large amount of thorium nitrate is being handled by these industries, contribution to the inhalation dose of workers from 220Rn gas emanated and build up of the progeny in ambient air may also be quite significant. In this paper current status of 220Rn levels in the indoor environment and workplaces as well as in other industries where large amount of 232Th is being handled is being summarized. Methods of measurement and reported levels are also summarized.

[Study on spectral detection of green plant target].

PubMed

Deng, Wei; Zhao, Chun-jiang; He, Xiong-kui; Chen, Li-ping; Zhang, Lu-da; Wu, Guang-wei; Mueller, J; Zhai, Chang-yuan

2010-08-01

Weeds grow scatteredly in fields, where many insentient objects exist, for example, withered grasses, dry twig and barriers. In order to improve the precision level of spraying, it is important to study green plant detecting technology. The present paper discussed detecting method of green plant by using spectral recognizing technology, because of the real-time feature of spectral recognition. By analyzing the reflectivity difference between each of the two sides of the "red edge" of the spectrum from plants and surrounding environment, green plant discriminat index (GPDI) is defined as the value which equals the reflectivity ratio at the wavelength of 850 nm divided by the reflectivity ratio at the wavelength of 650 nm. The original spectral data of green plants and the background were measured by using the handhold FieldSpec 3 Spectroradiometer manufactured by ASD Inc. in USA. The spectral data were processed to get the reflectivity of each measured objects and to work out the GPDI thereof as well. The classification model of green plant and its background was built up using decision tree method in order to obtain the threshold of GPDI to distinguish green plants and the background. The threshold of GPDI was chosen as 5.54. The detected object was recognized as green plant when it is GPDI>GPDITH, and vice versa. Through another test, the accuracy rate was verified which was 100% by using the threshold. The authors designed and developed the green plant detector based on single chip microcomputer (SCM) "AT89S51" and photodiode "OPT101" to realize detecting green plants from the background. After passing through two optical filters, the center wavelengths of which are 650 and 850 nm respectively, the reflected light from measured targets was detected by two photodiodes and converted into electrical signals. These analog signals were then converted to digital signals via an analog-to-digital converter (ADS7813) after being amplified by a signal amplifier (OP400). The converted digital signal of reflected light was eventually sent to the SCM (AT89S51) and was calculated and processed there. The processing results and the control signals were given out to actuate executive device to open or close the solenoid valve. The test results show that the level of detectivity of the designed detector was affected by the species, size, and density of weeds. The detectivity of broad-leaf species is higher than that of narrow-leaf species. Broad-leaf species are more easily detected than those narrow-leaf ones; the bigger the plants and the denser the leaves are, the higher the level of detectivity is.

Evaluation of a LiI(Eu) neutron detector with coincident double photodiode readout

NASA Astrophysics Data System (ADS)

Yang, H.; Menaa, N.; Bronson, F.; Kastner, M.; Venkataraman, R.; Mueller, W. F.

2011-10-01

Previous work showed that enriched 6Li halide scintillation crystal is a good candidate for portable neutron-sensitive detectors. Photodiode readout is a good alternative to PMT in compact devices. These detectors are often required to work in presence of a strong gamma background. Therefore, great discrimination against gamma rays is crucial. Because of the high Q-value of the 6Li(n,α) 3H reaction, the light yield of a neutron capture signal corresponds to 3-4 MeV gamma equivalent in spite of the quenching effect of heavily charged particles. As a result, energy discrimination is quite effective against gamma signals generated in thin crystals. However, direct gamma interactions inside the photodiode can create pulses whose amplitude is large enough to interfere with thermal neutron peak. This study shows an innovative design based on coincident readout to solve this problem. In this design, two photodiodes are attached on both sides of the LiI crystal. The output signal is only accepted when both photodiodes give out coincident output. The method is proved to effectively suppress background in the neutron window in a 420 mR/h 137Cs field down to the level of natural background.

NIF unconverted light and its influence on DANTE measurements

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

Girard, Frederic; Suter, Larry; Landen, Otto

2009-06-15

NIF laser facility produces 1053 nm light and a fundamental requirement for NIF is to give up to 1.8 MJ of 351 nm light for target physics experiments. The 351 nm light is provided by frequency tripling the 1053 nm light in nonlinear crystals in the final optics assembly, just before the laser light enters the target chamber. Since this tripling process is not 100% efficient, unconverted light from the conversion process also enters the chamber. This unconverted light does not directly hit the target but it can strike target support structures at average intensities of few TW/cm{sup 2} wheremore » it can generate unwanted, background soft x-rays that are measured by the soft x-ray diagnostic DANTE installed on the NIF target chamber. This diagnostic quantifies the x-radiation intensity inside the hohlraum by measuring the x-ray flux coming from the target's laser entrance hole. Due to its centimeter wide field of view, it integrates x-ray emission from both the flux exiting a hohlraum laser entrance hole and from the target support structure irradiated by residual 1{omega} and 2{omega} unconverted light. This work gives quantitative evaluations of the unconverted light for the first time and the effects on DANTE measurements for the future NIF tuning experiment called ''Shock timing.'' Emission spectra are significantly modified leading to an overestimation of radiative temperature during the foot of the laser pulse since background x-rays are predominant in first two DANTE channel measurements. Mitigations of these effects by coating silicon paddle with plastic, using a smaller collimator to reduce DANTE field of view or eliminating DANTE channels in the analysis have been investigated.« less

NIF unconverted light and its influence on DANTE measurements.

PubMed

Girard, Frederic; Suter, Larry; Landen, Otto; Munro, Dave; Regan, Sean; Kline, John

2009-06-01

NIF laser facility produces 1053 nm light and a fundamental requirement for NIF is to give up to 1.8 MJ of 351 nm light for target physics experiments. The 351 nm light is provided by frequency tripling the 1053 nm light in nonlinear crystals in the final optics assembly, just before the laser light enters the target chamber. Since this tripling process is not 100% efficient, unconverted light from the conversion process also enters the chamber. This unconverted light does not directly hit the target but it can strike target support structures at average intensities of few TW/cm2 where it can generate unwanted, background soft x-rays that are measured by the soft x-ray diagnostic DANTE installed on the NIF target chamber. This diagnostic quantifies the x-radiation intensity inside the hohlraum by measuring the x-ray flux coming from the target's laser entrance hole. Due to its centimeter wide field of view, it integrates x-ray emission from both the flux exiting a hohlraum laser entrance hole and from the target support structure irradiated by residual 1omega and 2omega unconverted light. This work gives quantitative evaluations of the unconverted light for the first time and the effects on DANTE measurements for the future NIF tuning experiment called "Shock timing." Emission spectra are significantly modified leading to an overestimation of radiative temperature during the foot of the laser pulse since background x-rays are predominant in first two DANTE channel measurements. Mitigations of these effects by coating silicon paddle with plastic, using a smaller collimator to reduce DANTE field of view or eliminating DANTE channels in the analysis have been investigated.

Optimization of fluorescent imaging in the operating room through pulsed acquisition and gating to ambient background cycling

PubMed Central

Sexton, Kristian J.; Zhao, Yan; Davis, Scott C.; Jiang, Shudong; Pogue, Brian W.

2017-01-01

The design of fluorescence imaging instruments for surgical guidance is rapidly evolving, and a key issue is to efficiently capture signals with high ambient room lighting. Here, we introduce a novel time-gated approach to fluorescence imaging synchronizing acquisition to the 120 Hz light of the room, with pulsed LED excitation and gated ICCD detection. It is shown that under bright ambient room light this technique allows for the detection of physiologically relevant nanomolar fluorophore concentrations, and in particular reduces the light fluctuations present from the room lights, making low concentration measurements more reliable. This is particularly relevant for the light bands near 700nm that are more dominated by ambient lights. PMID:28663895

A Near-Infrared Spectrometer to Measure Zodiacal Light Absorption Spectrum

NASA Technical Reports Server (NTRS)

Kutyrev, A. S.; Arendt, R.; Dwek, E.; Kimble, R.; Moseley, S. H.; Rapchun, D.; Silverberg, R. F.

2010-01-01

We have developed a high throughput infrared spectrometer for zodiacal light fraunhofer lines measurements. The instrument is based on a cryogenic dual silicon Fabry-Perot etalon which is designed to achieve high signal to noise Fraunhofer line profile measurements. Very large aperture silicon Fabry-Perot etalons and fast camera optics make these measurements possible. The results of the absorption line profile measurements will provide a model free measure of the zodiacal Light intensity in the near infrared. The knowledge of the zodiacal light brightness is crucial for accurate subtraction of zodiacal light foreground for accurate measure of the extragalactic background light after the subtraction of zodiacal light foreground. We present the final design of the instrument and the first results of its performance.

High sensitivity fluorescent single particle and single molecule detection apparatus and method

DOEpatents

Mathies, Richard A.; Peck, Konan; Stryer, Lubert

1990-01-01

Apparatus is described for ultrasensitive detection of single fluorescent particles down to the single fluorescent molecule limit in a fluid or on a substrate comprising means for illuminating a predetermined volume of the fluid or area of the substrate whereby to emit light including background light from the fluid and burst of photons from particles residing in the area. The photon burst is detected in real time to generate output representative signal. The signal is received and the burst of energy from the fluorescent particles is distinguished from the background energy to provide an indication of the number, location or concentration of the particles or molecules.

Easy approach to assembling a biomimetic color film with tunable structural colors.

PubMed

Wang, Wentao; Tang, Bingtao; Ma, Wei; Zhang, Jian; Ju, Benzhi; Zhang, Shufen

2015-06-01

The self-assembly of silica microspheres into a close-packed array is a simple method of fabricating three-dimensional photonic crystal structural color films. However, the color is very dull because of the interferences of scattering and background light. In this study, we added a small quantity of surface-modified carbon black (CB) to the system of colloidal silica in n-propanol. The use of n-propanol as a dispersant is beneficial to the rapid development of photonic crystal films during the process of dip-coating. The doping of CB into silica microspheres can absorb background and scattering light, resulting in vivid structural colors.

Investigation of Light-Emitting Diode (LED) Point Light Source Color Visibility against Complex Multicolored Backgrounds

DTIC Science & Technology

2017-11-01

sent from light-emitting diodes (LEDs) of 5 colors ( green , red, white, amber, and blue). Experiment 1 involved controlled laboratory measurements of...A-4 Red LED calibration curves and quadratic curve fits with R2 values . 37 Fig. A-5 Green LED calibration curves and quadratic curve fits with R2...36 Table A-4 Red LED calibration measurements ................................................... 36 Table A-5 Green LED

Mapping Boron Dioxide (BO2) Light Emission During Ballistic Initiation of Boron

DTIC Science & Technology

2016-03-03

Dreizin; unreferenced). Essentially, 2 light sensors (cameras), each filtered over a narrow wavelength region, observe an event over the same line of...background incandescence (subtraction gave a qualitatively similar result). For imaging BO2 emission, the light sensors were 2 Phantom V7.3 monochrome...A check of the temperature measurement technique using emission from an acetylene/air diffusion flame gave reasonable results (1,800 K outer soot

Can we discover double Higgs production at the LHC?

NASA Astrophysics Data System (ADS)

Alves, Alexandre; Ghosh, Tathagata; Sinha, Kuver

2017-08-01

We explore double Higgs production via gluon fusion in the b b ¯γ γ channel at the high-luminosity LHC using machine learning tools. We first propose a Bayesian optimization approach to select cuts on kinematic variables, obtaining a 30%-50% increase in the significance compared to current results in the literature. We show that this improvement persists once systematic uncertainties are taken into account. We next use boosted decision trees (BDT) to further discriminate signal and background events. Our analysis shows that a joint optimization of kinematic cuts and BDT hyperparameters results in an appreciable improvement in the significance. Finally, we perform a multivariate analysis of the output scores of the BDT. We find that assuming a very low level of systematics, the techniques proposed here will be able to confirm the production of a pair of standard model Higgs bosons at 5 σ level with 3 ab-1 of data. Assuming a more realistic projection of the level of systematics, around 10%, the optimization of cuts to train BDTs combined with a multivariate analysis delivers a respectable significance of 4.6 σ . Even assuming large systematics of 20%, our analysis predicts a 3.6 σ significance, which represents at least strong evidence in favor of double Higgs production. We carefully incorporate background contributions coming from light flavor jets or c jets being misidentified as b jets and jets being misidentified as photons in our analysis.

A Preliminary Study of the Safety of Red Light Phototherapy of Tissues Harboring Cancer

PubMed Central

Stadler, Istvan; Brondon, Philip; Axe, David R.; Friedman, Mark; Nardia, Frances Barg; Lanzafame, Raymond

2012-01-01

Abstract Objective: Red light phototherapy is known to stimulate cell proliferation in wound healing. This study investigated whether low-level light therapy (LLLT) would promote tumor growth when pre-existing malignancy is present. Background data: LLLT has been increasingly used for numerous conditions, but its use in cancer patients, including the treatment of lymphedema or various unrelated comorbidities, has been withheld by practitioners because of the fear that LLLT might result in initiation or promotion of metastatic lesions or new primary tumors. There has been little scientific study of oncologic outcomes after use of LLLT in cancer patients. Methods: A standard SKH mouse nonmelanoma UV-induced skin cancer model was used after visible squamous cell carcinomas were present, to study the effects of LLLT on tumor growth. The red light group (n=8) received automated full body 670 nm LLLT delivered twice a day at 5 J/cm2 using an LED source. The control group (n=8) was handled similarly, but did not receive LLLT. Measurements on 330 tumors were conducted for 37 consecutive days, while the animals received daily LLLT. Results: Daily tumor measurements demonstrated no measurable effect of LLLT on tumor growth. Conclusions: This experiment suggests that LLLT at these parameters may be safe even when malignant lesions are present. Further studies on the effects of photoirradiation on neoplasms are warranted. PMID:22853435

Fluorescent sensing with Fresnel microlenses for optofluidic systems

NASA Astrophysics Data System (ADS)

Siudzińska, Anna; Miszczuk, Andrzej; Marczak, Jacek; Komorowska, Katarzyna

2017-05-01

The concept of fluorescent sensing in a microchannel equipped with focusing light Fresnel lenses has been demonstrated. The concept employs a line or array of Fresnel lenses generating a line or array of focused light spots within a microfluidic channel, to increase the sensitivity of fluorescent signal detection in the system. We have presented efficient methods of master mold fabrication based on the lithography method and focused ion beam milling. The flexible microchannel was fabricated by an imprint process with new thiolene-epoxy resin with a good ability to replicate even submicron-size features. For final imprinted lenses, the measured background to peak signal level shows more than nine times the increase in brightness at the center of the focal spot for the green part of the spectrum (532 nm). The effectiveness of the microlenses in fluorescent-marked Escherichia coli bacteria was confirmed in a basic fluoroscope experiment, showing the increase of the sensitivity of the detection by the order of magnitude.

Nano-imaging enabled via self-assembly

PubMed Central

McLeod, Euan; Ozcan, Aydogan

2014-01-01

SUMMARY Imaging object details with length scales below approximately 200 nm has been historically difficult for conventional microscope objective lenses because of their inability to resolve features smaller than one-half the optical wavelength. Here we review some of the recent approaches to surpass this limit by harnessing self-assembly as a fabrication mechanism. Self-assembly can be used to form individual nano- and micro-lenses, as well as to form extended arrays of such lenses. These lenses have been shown to enable imaging with resolutions as small as 50 nm half-pitch using visible light, which is well below the Abbe diffraction limit. Furthermore, self-assembled nano-lenses can be used to boost contrast and signal levels from small nano-particles, enabling them to be detected relative to background noise. Finally, alternative nano-imaging applications of self-assembly are discussed, including three-dimensional imaging, enhanced coupling from light-emitting diodes, and the fabrication of contrast agents such as quantum dots and nanoparticles. PMID:25506387

Simulated performance of the optical Thomson scattering diagnostic designed for the National Ignition Facility.

PubMed

Ross, J S; Datte, P; Divol, L; Galbraith, J; Froula, D H; Glenzer, S H; Hatch, B; Katz, J; Kilkenny, J; Landen, O; Manuel, A M; Molander, W; Montgomery, D S; Moody, J D; Swadling, G; Weaver, J

2016-11-01

An optical Thomson scattering diagnostic has been designed for the National Ignition Facility to characterize under-dense plasmas. We report on the design of the system and the expected performance for different target configurations. The diagnostic is designed to spatially and temporally resolve the Thomson scattered light from laser driven targets. The diagnostic will collect scattered light from a 50 × 50 × 200 μm volume. The optical design allows operation with different probe laser wavelengths. A deep-UV probe beam (λ 0 = 210 nm) will be used to Thomson scatter from electron plasma densities of ∼5 × 10 20 cm -3 while a 3ω probe will be used for plasma densities of ∼1 × 10 19 cm -3 . The diagnostic package contains two spectrometers: the first to resolve Thomson scattering from ion acoustic wave fluctuations and the second to resolve scattering from electron plasma wave fluctuations. Expected signal levels relative to background will be presented for typical target configurations (hohlraums and a planar foil).

Simulating halos and coronas in their atmospheric environment.

PubMed

David Gedzelman, Stanley

2008-12-01

Models are developed that simulate the light and color of the sky and of circular halos and coronas as a function of atmospheric pressure, cloud height, width, and optical depth, solar zenith angle, aerosol concentration and size, and ozone content. Halos, coronas, and skylight are treated as singly scattered sunbeams that are depleted in their passage through the atmosphere and cloud. Multiple scattering is included only for background cloud light. Halos produced by hexagonal crystal prisms and coronas produced by monodisperse droplets are visible for cloud optical depths in the range 0.0003

Transcriptome analysis of intraspecific competition in Arabidopsis thaliana reveals organ-specific signatures related to nutrient acquisition and general stress response pathways

PubMed Central

2012-01-01

Background Plants are sessile and therefore have to perceive and adjust to changes in their environment. The presence of neighbours leads to a competitive situation where resources and space will be limited. Complex adaptive responses to such situation are poorly understood at the molecular level. Results Using microarrays, we analysed whole-genome expression changes in Arabidopsis thaliana plants subjected to intraspecific competition. The leaf and root transcriptome was strongly altered by competition. Differentially expressed genes were enriched in genes involved in nutrient deficiency (mainly N, P, K), perception of light quality, and responses to abiotic and biotic stresses. Interestingly, performance of the generalist insect Spodoptera littoralis on densely grown plants was significantly reduced, suggesting that plants under competition display enhanced resistance to herbivory. Conclusions This study provides a comprehensive list of genes whose expression is affected by intraspecific competition in Arabidopsis. The outcome is a unique response that involves genes related to light, nutrient deficiency, abiotic stress, and defence responses. PMID:23194435

Computational Modeling to Limit the Impact Displays and Indicator Lights Have on Habitable Volume Operational Lighting Constraints

NASA Technical Reports Server (NTRS)

Clark, T. A.; Brainard, G.; Salazar, G.; Johnston, S.; Schwing, B.; Litaker, H.; Kolomenski, A.; Venus, D.; Tran, K.; Hanifin, J.;

First Limit on the Direct Detection of Lightly Ionizing Particles for Electric Charge as Low as e / 1000 with the Majorana Demonstrator

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

Alvis, S. I.; Arnquist, I. J.; Avignone, F. T.

The Majorana Demonstrator is an ultralow-background experiment searching for neutrinoless double-beta decay in 76Ge. The heavily shielded array of germanium detectors, placed nearly a mile underground at the Sanford Underground Research Facility in Lead, South Dakota, also allows searches for new exotic physics. Free, relativistic, lightly ionizing particles with an electrical charge less than e are forbidden by the standard model but predicted by some of its extensions. If such particles exist, they might be detected in the Majorana Demonstrator by searching for multiple-detector events with individual-detector energy depositions down to 1 keV. This search is background-free, and no candidatemore » events have been found in 285 days of data taking. As a result, new direct-detection limits are set for the flux of lightly ionizing particles for charges as low as e/1000.« less

First Limit on the Direct Detection of Lightly Ionizing Particles for Electric Charge as Low as e /1000 with the Majorana Demonstrator

NASA Astrophysics Data System (ADS)

Alvis, S. I.; Arnquist, I. J.; Avignone, F. T.; Barabash, A. S.; Barton, C. J.; Bertrand, F. E.; Brudanin, V.; Busch, M.; Buuck, M.; Caldwell, T. S.; Chan, Y.-D.; Christofferson, C. D.; Chu, P.-H.; Cuesta, C.; Detwiler, J. A.; Dunagan, C.; Efremenko, Yu.; Ejiri, H.; Elliott, S. R.; Gilliss, T.; Giovanetti, G. K.; Green, M. P.; Gruszko, J.; Guinn, I. S.; Guiseppe, V. E.; Haufe, C. R.; Hehn, L.; Henning, R.; Hoppe, E. W.; Howe, M. A.; Konovalov, S. I.; Kouzes, R. T.; Lopez, A. M.; Martin, R. D.; Massarczyk, R.; Meijer, S. J.; Mertens, S.; Myslik, J.; O'Shaughnessy, C.; Othman, G.; Pettus, W.; Poon, A. W. P.; Radford, D. C.; Rager, J.; Reine, A. L.; Rielage, K.; Robertson, R. G. H.; Ruof, N. W.; Shanks, B.; Shirchenko, M.; Suriano, A. M.; Tedeschi, D.; Varner, R. L.; Vasilyev, S.; Vorren, K.; White, B. R.; Wilkerson, J. F.; Wiseman, C.; Xu, W.; Yakushev, E.; Yu, C.-H.; Yumatov, V.; Zhitnikov, I.; Zhu, B. X.; Majorana Collaboration

2018-05-01

The Majorana Demonstrator is an ultralow-background experiment searching for neutrinoless double-beta decay in 76Ge. The heavily shielded array of germanium detectors, placed nearly a mile underground at the Sanford Underground Research Facility in Lead, South Dakota, also allows searches for new exotic physics. Free, relativistic, lightly ionizing particles with an electrical charge less than e are forbidden by the standard model but predicted by some of its extensions. If such particles exist, they might be detected in the Majorana Demonstrator by searching for multiple-detector events with individual-detector energy depositions down to 1 keV. This search is background-free, and no candidate events have been found in 285 days of data taking. New direct-detection limits are set for the flux of lightly ionizing particles for charges as low as e /1000 .

Motion compensation for structured light sensors

NASA Astrophysics Data System (ADS)

Biswas, Debjani; Mertz, Christoph

2015-05-01

In order for structured light methods to work outside, the strong background from the sun needs to be suppressed. This can be done with bandpass filters, fast shutters, and background subtraction. In general this last method necessitates the sensor system to be stationary during data taking. The contribution of this paper is a method to compensate for the motion if the system is moving. The key idea is to use video stabilization techniques that work even if the illuminator is switched on and off from one frame to another. We used OpenCV functions and modules to implement a robust and efficient method. We evaluated it under various conditions and tested it on a moving robot outdoors. We will demonstrate that one can not only do 3D reconstruction under strong ambient light, but that it is also possible to observe optical properties of the objects in the environment.

CALDER: Cryogenic light detectors for background-free searches

NASA Astrophysics Data System (ADS)

Di Domizio, S.; Bellini, F.; Cardani, L.; Casali, N.; Castellano, M. G.; Colantoni, I.; Cosmelli, C.; Cruciani, A.; D'Addabbo, A.; Martinez, M.; Minutolo, L.; Tomei, C.; Vignati, M.

2018-01-01

CALDER is a R&D project for the development of cryogenic light detectors with an active surface of 5x5cm2 and an energy resolution of 20 eV RMS for visible and UV photons. These devices can enhance the sensitivity of next generation large mass bolometric detectors for rare event searches, providing an active background rejection method based on particle discrimination. A CALDER detector is composed by a large area Si absorber substrate with superconducting kinetic inductance detectors (KIDs) deposited on it. The substrate converts the incoming light into athermal phonons, that are then sensed by the KIDs. KID technology combine fabrication simplicity with natural attitude to frequency-domain multiplexing, making it an ideal candidate for a large scale bolometric experiments. We will give an overview of the CALDER project and show the performances obtained with prototype detectors both in terms of energy resolution and efficiency.

First Limit on the Direct Detection of Lightly Ionizing Particles for Electric Charge as Low as e / 1000 with the Majorana Demonstrator

DOE PAGES

Alvis, S. I.; Arnquist, I. J.; Avignone, F. T.; ...

2018-05-25

The Majorana Demonstrator is an ultralow-background experiment searching for neutrinoless double-beta decay in 76Ge. The heavily shielded array of germanium detectors, placed nearly a mile underground at the Sanford Underground Research Facility in Lead, South Dakota, also allows searches for new exotic physics. Free, relativistic, lightly ionizing particles with an electrical charge less than e are forbidden by the standard model but predicted by some of its extensions. If such particles exist, they might be detected in the Majorana Demonstrator by searching for multiple-detector events with individual-detector energy depositions down to 1 keV. This search is background-free, and no candidatemore » events have been found in 285 days of data taking. As a result, new direct-detection limits are set for the flux of lightly ionizing particles for charges as low as e/1000.« less

Association between Self-Reported Smoking and Hemoglobin A1c in a Korean Population without Diabetes: The 2011–2012 Korean National Health and Nutrition Examination Survey

PubMed Central

Hong, Jae Won; Ku, Cheol Ryong; Noh, Jung Hyun; Ko, Kyung Soo; Rhee, Byoung Doo; Kim, Dong-Jun

2015-01-01

Background Several Western studies have revealed that among non-diabetics, glycosylated hemoglobin A1c (HbA1c) levels are higher in smokers than non-smokers. While studies conducted in Western populations consistently support this association, a recent meta-analysis reported that studies carried out in non-Western populations, including studies of Chinese, Egyptian, and Japanese-Americans, did not detect any significant differences in HbA1c levels between smokers and non-smokers. Objectives We assessed the association between smoking habits and HbA1c levels in the general Korean adult population using data from the Korean National Health and Nutrition Examination Survey (KNHANES) performed in 2011–2012. Methods A total of 10,241 participants (weighted n=33,946,561 including 16,769,320 men and 17,177,241 women) without diabetes were divided into four categories according to their smoking habits: never smokers (unweighted n/ weighted n= 6,349/19,105,564), ex-smokers (unweighted n/ weighted n= 1,912/6,207,144), current light smokers (<15 cigarettes per day, unweighted n/ weighted n=1,205/5,130,073), and current heavy smokers (≥15 cigarettes per day, unweighted n/ weighted n=775/3,503,781). Results In age- and gender-adjusted comparisons, the HbA1c levels of each group were 5.52 ± 0.01% in non-smokers, 5.49 ± 0.01% in ex-smokers, 5.53 ± 0.01% in light smokers, and 5.61 ± 0.02% in heavy smokers. HbA1c levels were significantly higher in light smokers than in ex-smokers (p = 0.033), and in heavy smokers compared with light smokers (p < 0.001). The significant differences remained after adjusting for age, gender, fasting plasma glucose, heavy alcohol drinking, hematocrit, college graduation, and waist circumference. Linear regression analyses for HbA1c using the above-mentioned variables as covariates revealed that a significant association between current smoking and HbA1c (coefficient 0.021, 95% CI 0.003–0.039, p = 0.019). Conclusions Current smoking was independently associated with higher HbA1c levels in a cigarette exposure-dependent manner in a representative population of Korean non-diabetic adults. In this study, we have observed an association between smoking status and HbA1c levels in non-diabetics drawn from a non-Western population, consistent with previous findings in Western populations. PMID:26011526

Enhanced Global Signal of Neutral Hydrogen Due to Excess Radiation at Cosmic Dawn

NASA Astrophysics Data System (ADS)

Feng, Chang; Holder, Gilbert

2018-05-01

We revisit the global 21 cm signal calculation incorporating a possible radio background at early times, and find that the global 21 cm signal shows a much stronger absorption feature, which could enhance detection prospects for future 21 cm experiments. In light of recent reports of a possible low-frequency excess radio background, we propose that detailed 21 cm calculations should include a possible early radio background.

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

PubMed Central

Versteeg, Ruth I.; Stenvers, Dirk J.; Visintainer, Dana; Linnenbank, Andre; Tanck, Michael W.; Zwanenburg, Gooitzen; Smilde, Age K.; Fliers, Eric; Kalsbeek, Andries; Serlie, Mireille J.; la Fleur, Susanne E.; Bisschop, Peter H.

2017-01-01

Ambient light intensity is signaled directly to hypothalamic areas that regulate energy metabolism. Observational studies have shown associations between ambient light intensity and plasma glucose and lipid levels, but human data on the acute metabolic effects of light are scarce. Since light is the main signal indicating the onset of the diurnal phase of physical activity and food intake in humans, we hypothesized that bright light would affect glucose and lipid metabolism. Therefore, we determined the acute effects of bright light on plasma glucose and lipid concentrations in 2 randomized crossover trials: (1) in 8 healthy lean men and (2) in 8 obese men with type 2 diabetes. From 0730 h, subjects were exposed to either bright light (4000 lux) or dim light (10 lux) for 5 h. After 1 h of light exposure, subjects consumed a 600-kcal mixed meal. Primary endpoints were fasting and postprandial plasma glucose levels. In healthy men, bright light did not affect fasting or postprandial plasma glucose levels. However, bright light increased fasting and postprandial plasma triglycerides. In men with type 2 diabetes, bright light increased fasting and postprandial glucose levels. In men with type 2 diabetes, bright light did not affect fasting triglyceride levels but increased postprandial triglyceride levels. We show that ambient light intensity acutely affects human plasma glucose and triglyceride levels. Our findings warrant further research into the consequences of the metabolic effects of light for the diagnosis and prevention of hyperglycemia and dyslipidemia. PMID:28470119

Pioneer 10 observations of zodiacal light brightness near the ecliptic - Changes with heliocentric distance

NASA Technical Reports Server (NTRS)

Hanner, M. S.; Weinberg, J. L.; Beeson, D. E.; Sparrow, J. G.

1976-01-01

Sky maps made by the Pioneer 10 Imaging Photopolarimeter (IPP) at sun-spacecraft distances from 1 to 3 AU have been analyzed to derive the brightness of the zodiacal light near the ecliptic at elongations greater than 90 degrees. The change in zodiacal light brightness with heliocentric distance is compared with models of the spatial distribution of the dust. Use of background starlight brightnesses derived from IPP measurements beyond the asteroid belt, where the zodiacal light is not detected, and, especially, use of a corrected calibration lead to considerably lower values for zodiacal light than those reported by us previously.

Effect of UV-B light on total soluble phenolic contents of various whole and fresh-cut specialty crops

USDA-ARS?s Scientific Manuscript database

BACKGROUND: The effect of ultraviolet-B (UV-B) light treatment on total soluble phenolic contents (TSP) of various whole and fresh-cut specialty crops was evaluated. Whole fruits (strawberries, blueberries, grapes), vegetables (cherry tomatoes, white sweet corn) and root crops (sweet potatoes, colo...

The Skylab ten color photoelectric polarimeter. [sky brightness

NASA Technical Reports Server (NTRS)

Weinberg, J. L.; Hahn, R. C.; Sparrow, J. G.

1975-01-01

A 10-color photoelectric polarimeter was used during Skylab missions SL-2 and SL-3 to measure sky brightness and polarization associated with zodiacal light, background starlight, and the spacecraft corona. A description is given of the instrument and observing routines together with initial results on the spacecraft corona and polarization of the zodiacal light.

75 FR 9958 - Carolina Power & Light Company, Shearon Harris Nuclear Power Plant, Unit 1; Exemption

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-04

..., Shearon Harris Nuclear Power Plant, Unit 1; Exemption 1.0 Background Carolina Power & Light Company (the... Operating License No. NPF-63, which authorizes operation of the Shearon Harris Nuclear Power Plant, Unit 1... rule's compliance date for all operating nuclear power plants, but noted that the Commission's...

Evidence for an Inducible Repair-Recombination System in the Female Germ Line of Drosophila Melanogaster. III. Correlation between Reactivity Levels, Crossover Frequency and Repair Efficiency

PubMed Central

Laurencon, A.; Gay, F.; Ducau, J.; Bregliano, J. C.

1997-01-01

We previously reported evidence that the so-called reactivity level, a peculiar cellular state of oocytes that regulates the frequency of transposition of I factor, a LINE element-like retrotransposon, might be one manifestation of a DNA repair system. In this article, we report data showing that the reactivity level is correlated with the frequency of crossing over, at least on the X chromosome and on the pericentromeric region of the third chromosome. Moreover, a check for X-chromosome losses and recessive lethals produced after gamma irradiation in flies with different reactivity levels, but common genetic backgrounds, brings more precise evidence for the relationship between reactivity levels and DNA repair. Those results support the existence of a repair-recombination system whose efficiency is modulated by endogenous and environmental factors. The implications of this biological system in connecting genomic variability and environment may shed new lights on adaptative mechanisms. We propose to call it VAMOS for variability modulation system. PMID:9258678

SU-F-T-166: On the Nature of the Background Visible Light Observed in Fiber Optic Dosimetry of Proton Beams

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

Darafsheh, A; Kassaee, A; Finlay, J

Purpose: The nature of the background visible light observed during fiber optic dosimetry of proton beams, whether it is due to Cherenkov radiation or not, has been debated in the literature recently. In this work, experimentally and by means of Monte Carlo simulations, we shed light on this problem and investigated the nature of the background visible light observed in fiber optics irradiated with proton beams. Methods: A bare silica fiber optics was embedded in tissue-mimicking phantoms and irradiated with clinical proton beams with energies of 100–225 MeV at Roberts Proton Therapy Center. Luminescence spectroscopy was performed by a CCD-coupledmore » spectrograph to analyze in detail the emission spectrum of the fiber tip across the visible range of 400–700 nm. Monte Carlo simulation was performed by using FLUKA Monte Carlo code to simulate Cherenkov light and ionizing radiation dose deposition in the fiber. Results: The experimental spectra of the irradiated silica fiber shows two distinct peaks at 450 and 650 nm, whose spectral shape is different from that of Cherenkov radiation. We believe that the nature of these peaks are connected to the point defects of silica including oxygen-deficiency center (ODC) and non-bridging oxygen hole center (NBOHC). Monte Carlo simulations confirmed the experimental observations that Cherenkov radiation cannot be solely responsible for such a signal. Conclusion: We showed that Cherenkov radiation is not the dominant visible signal observed in bare fiber optics irradiated with proton beams. We observed two distinct peaks at 450 and 650 nm whose nature is connected with the point defects of silica fiber including oxygen-deficiency center and non-bridging oxygen hole center.« less

Real-time alkali monitoring system

DOEpatents

Goff, David R.; Romanosky, Robert R.; Hensel, Peter

1990-01-01

A fiber optics based optical emission line monitoring system is provided in which selected spectral emission lines, such as the sodium emission line, may be detected in the presence of interfering background radiation. A combustion flame is fed by a diverted portion of a process stream and the common end of a bifurcated or quadfurcated fiber optic light guide is adapted to collect light from the flame. The light is guided through the branches of the fiber optic cable to bandpass filters, one of which is adapted to each of the branches of the fiber optic light guide. The bandpass filters are centered at wavelengths corresponding to the emission lines to be detected and two separate filters are required for each species being detected. The first filter has a bandwidth of about 3 nms and the second filter has a bandwidth of about 10 nms. Light detectors are located to view the light passing through the bandpass filters and amplifiers are connected to receive signals from the light detectors. The amplifier corresponding to the bandpass filter having the narrower bandwidth is preset to scale the signal by a factor equal to the ratio of the wide and narrow bandwidths of the bandpass filters. This scaling produces a scaled signal from which the difference between the scaled signal on the other signal can be calculated to produce a signal having an amplitude directly proportional to the concentration of the species of interest and independent of background radiation.

Effect of Age and Glaucoma on the Detection of Darks and Lights

PubMed Central

Zhao, Linxi; Sendek, Caroline; Davoodnia, Vandad; Lashgari, Reza; Dul, Mitchell W.; Zaidi, Qasim; Alonso, Jose-Manuel

2015-01-01

Purpose We have shown previously that normal observers detect dark targets faster and more accurately than light targets, when presented in noisy backgrounds. We investigated how these differences in detection time and accuracy are affected by age and ganglion cell pathology associated with glaucoma. Methods We asked 21 glaucoma patients, 21 age-similar controls, and 5 young control observers to report as fast as possible the number of 1 to 3 light or dark targets. The targets were positioned at random in a binary noise background, within the central 30° of the visual field. Results We replicate previous findings that darks are detected faster and more accurately than lights. We extend these findings by demonstrating that differences in detection of darks and lights are found reliably across different ages and in observers with glaucoma. We show that differences in detection time increase at a rate of approximately 55 msec/dB at early stages of glaucoma and then remain constant at later stages at approximately 800 msec. In normal subjects, differences in detection time increase with age at a rate of approximately 8 msec/y. We also demonstrate that the accuracy to detect lights and darks is significantly correlated with the severity of glaucoma and that the mean detection time is significantly longer for subjects with glaucoma than age-similar controls. Conclusions We conclude that differences in detection of darks and lights can be demonstrated over a wide range of ages, and asymmetries in dark/light detection increase with age and early stages of glaucoma. PMID:26513506

Effect of Age and Glaucoma on the Detection of Darks and Lights.

PubMed

Zhao, Linxi; Sendek, Caroline; Davoodnia, Vandad; Lashgari, Reza; Dul, Mitchell W; Zaidi, Qasim; Alonso, Jose-Manuel

2015-10-01

We have shown previously that normal observers detect dark targets faster and more accurately than light targets, when presented in noisy backgrounds. We investigated how these differences in detection time and accuracy are affected by age and ganglion cell pathology associated with glaucoma. We asked 21 glaucoma patients, 21 age-similar controls, and 5 young control observers to report as fast as possible the number of 1 to 3 light or dark targets. The targets were positioned at random in a binary noise background, within the central 30° of the visual field. We replicate previous findings that darks are detected faster and more accurately than lights. We extend these findings by demonstrating that differences in detection of darks and lights are found reliably across different ages and in observers with glaucoma. We show that differences in detection time increase at a rate of approximately 55 msec/dB at early stages of glaucoma and then remain constant at later stages at approximately 800 msec. In normal subjects, differences in detection time increase with age at a rate of approximately 8 msec/y. We also demonstrate that the accuracy to detect lights and darks is significantly correlated with the severity of glaucoma and that the mean detection time is significantly longer for subjects with glaucoma than age-similar controls. We conclude that differences in detection of darks and lights can be demonstrated over a wide range of ages, and asymmetries in dark/light detection increase with age and early stages of glaucoma.

Lights, Cameras, Mirrors, Action!

ERIC Educational Resources Information Center

Purcell, John

2012-01-01

In this article, the author describes how his first-grade students made their own compositions based on James Rosenquist's collage series in which long shards of faces were painted over a background that appeared to be abstract. The background was made up of enlarged details of things such as flowers, leaves, fire, and water. The students'…

Social Pedagogical Work with Different Age Groups in Germany

ERIC Educational Resources Information Center

Toporkova, Olga; Glebova, Ekaterina; Vysotskaia, Inna V.; Tikhaeva, Victoria V.

2016-01-01

Background/Objectives: The main objective of the article is to study, analyze and organize the modern German experience in the sphere of social pedagogical and educational work with socially unprotected adults, including youth and the elderly. The retrospective analysis threw light on the background of work with socially unprotected adults in…

Detecting and Characterizing Nighttime Lighting Using Multispectral and Hyperspectral Imaging

DTIC Science & Technology

2012-12-01

OBJECTIVES...............................................................................2  II.  BACKGROUND ...accomplish the same. 3 II. BACKGROUND The approach to extracting information from optical remote sensing at night is slightly different than...although it occupies a very small region within the EMS. Other familiar forms of energy that lie along the spectrum include, cosmic rays, gamma rays, x

The cosmic infrared background experiment (CIBER): instrumentation and first results

NASA Astrophysics Data System (ADS)

Zemcov, M.; Battle, J.; Bock, J.; Cooray, A.; Hristov, V.; Keating, B.; Lee, D. H.; Levenson, L.; Mason, P.; Matsumoto, T.; Matsuura, S.; Nam, U. W.; Renbarger, T.; Sullivan, I.; Tsumura, K.; Wada, T.

2010-07-01

Ultraviolet emission from the first generation of stars in the Universe ionized the intergalactic medium in a process which was completed by z ~ 6; the wavelength of these photons has been redshifted by (1 + z) into the near infrared today and can be measured using instruments situated above the Earth's atmosphere. First flying in February 2009, the Cosmic Infrared Background ExpeRiment (CIBER) comprises four instruments housed in a single reusable sounding rocket borne payload. CIBER will measure spatial anisotropies in the extragalactic IR background caused by cosmological structure from the epoch of reionization using two broadband imaging instruments, make a detailed characterization of the spectral shape of the IR background using a low resolution spectrometer, and measure the absolute brightness of the Zodiacal light foreground with a high resolution spectrometer in each of our six science fields. The scientific motivation for CIBER and details of its first and second flight instrumentation will be discussed. First flight results on the color of the zodiacal light around 1 μm and plans for the future will also be presented.

A comparison of the light-reduction capacity of commonly used incubator covers.

PubMed

Lee, Yi-Hui; Malakooti, Nima; Lotas, Marilyn

2005-01-01

The use of incubator covers to enhance preterm infants' rest and recovery is common in the NICU. However, the kinds of covers used vary extensively among and within nurseries. Few data exist on the effectiveness of different types of covers in reducing light levels to the infant. This study compared several types of commonly used incubator covers as to efficacy of light reduction. A descriptive, comparative design was used in this study. Twenty-three incubator covers were tested, including professional, receiving blanket, hand-crocheted, three-layer quilt, and flannel. The percentage of light level reduction of different incubator covers under various ambient light level settings. The amount of light reduction provided by incubator covers varies depending on type of fabric as well as percentage of incubator surface shielded by the cover. Dark-colored covers provided greater light reduction than bright/light-colored covers when covers identical in fabric type were compared. The light-reduction efficiency of the covers varied depending on the level of ambient light. Covers provided less light reduction in higher ambient light levels.

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

Cardani, L.; Bellini, F.; Casali, N.

The development of background-free detectors is essential for experiments searching for rare events. Bolometers, that are among the most competitive devices for the study of neutrino-less double beta decay (0νDBD) and Dark Matter interactions, suffer from the absence of techniques that allow to identify the nature of the interacting particles. This limit can be overcome by coupling the bolometer to an independent device for the measurement of the light emitted by interactions, as the combined read-out of the bolometric and light signals allows to identify and reject particles different from those of interest. CUORE, the most advanced bolometric experiment formore » 0νDBD searches, could disentangle the electrons produced by 0νDBD from the dangerous background due to α particles, by measuring the (tiny) Cherenkov light emitted by electrons and not by α’s. LUCIFER, a project based on ZnSe scintillating bolometers for the study of {sup 82}Se 0νDBD, would be competitive also in the search of Dark Matter interactions if equipped with light detectors that allow to distinguish and reject the background due to electrons and γ’s. These advances require cryogenic detectors characterized by noise lower than 20 eV, large active area, wide temperature range of operation, high radio-purity and ease in fabricating hundreds of channels. The CALDER collaboration aims to develop such detectors by exploiting the superb energy resolution and natural multiplexed read-out provided by Kinetic Inductance Detectors.« less

Improving Range Estimation of a 3-Dimensional Flash Ladar via Blind Deconvolution

DTIC Science & Technology

2010-09-01

12 2.1.4 Optical Imaging as a Linear and Nonlinear System 15 2.1.5 Coherence Theory and Laser Light Statistics . . . 16 2.2 Deconvolution...rather than deconvolution. 2.1.5 Coherence Theory and Laser Light Statistics. Using [24] and [25], this section serves as background on coherence theory...the laser light incident on the detector surface. The image intensity related to different types of coherence is governed by the laser light’s spatial

Tretinoin Photostability

PubMed Central

Rosso, James Del; Harper, Julie; Pillai, Radhakrishnan; Moore, Robert

2013-01-01

Background: Various formulations of tretinoin have been reported to be unstable after exposure to artificial light or sunlight. The observation that tretinoin is photolabile in the presence of light led to the recommendation that tretinoin be applied in the evening in order to avoid photodegradation, which could potentially reduce efficacy. More recently, the development of innovative vehicle formulations has led, in some cases, to a marked decrease in the photodegradation of tretinoin. Objective: To compare the photostability of a micronized aqueous-based formulation of tretinoin gel 0.05% with tretinoin gel 0.025% following exposure to fluorescent and simulated solar light conditions in vitro. Methods: Micronized tretinoin gel 0.05% and tretinoin gel 0.025% were exposed to fluorescent light over eight hours or simulated solar light up to 600mJ/cm2 (equivalent to 30 minimal erythemal dose). Product samples were prepared and analyzed for tretinoin concentration using high-performance liquid chromatography. Additional duplicate samples were similarly prepared and analyzed after 2, 4, 6, and 8 hours. Results: There was an 11-percent degradation of tretinoin 0.05% formulated as the micronized gel compared to an 86-percent degradation of tretinoin 0.025% formulated as the conventional gel following eight hours of exposure to fluorescent light in vitro. The degradation of tretinoin 0.025% in the conventional gel was greater than 83 percent within two hours. In the second light exposure study, in vitro exposure to simulated solar light provided a gradual dose-response effect with tretinoin 0.05% formulated as the micronized tretinoin gel. The photodegradation of tretinoin 0.025% in the conventional gel was more immediate and of substantial magnitude (>85%) after exposures at all minimal erythemal dose levels. Conclusion: Tretinoin 0.05% formulated as a micronized gel 0.05% showed minimal degradation when exposed to fluorescent light over eight hours. This same formulation exhibited a clear dose-response degradation pattern when exposed to simulated solar light. In contrast, tretinoin 0.025% formulated in a conventional gel exhibited marked photodegradation within the first two hours when exposed to both light conditions in vitro. This information adds to the body of evidence that supports the observation that certain vehicle formulations may reduce the potential for photodegradation of tretinoin. PMID:23441237

Scanning thin-sheet laser imaging microscopy (sTSLIM) with structured illumination and HiLo background rejection.

PubMed

Schröter, Tobias J; Johnson, Shane B; John, Kerstin; Santi, Peter A

2012-01-01

We report replacement of one side of a static illumination, dual sided, thin-sheet laser imaging microscope (TSLIM) with an intensity modulated laser scanner in order to implement structured illumination (SI) and HiLo image demodulation techniques for background rejection. The new system is equipped with one static and one scanned light-sheet and is called a scanning thin-sheet laser imaging microscope (sTSLIM). It is an optimized version of a light-sheet fluorescent microscope that is designed to image large specimens (<15 mm in diameter). In this paper we describe the hardware and software modifications to TSLIM that allow for static and uniform light-sheet illumination with SI and HiLo image demodulation. The static light-sheet has a thickness of 3.2 µm; whereas, the scanned side has a light-sheet thickness of 4.2 µm. The scanned side images specimens with subcellular resolution (<1 µm lateral and <4 µm axial resolution) with a size up to 15 mm. SI and HiLo produce superior contrast compared to both the uniform static and scanned light-sheets. HiLo contrast was greater than SI and is faster and more robust than SI because as it produces images in two-thirds of the time and exhibits fewer intensity streaking artifacts. 2011 Optical Society of America

An LED light source and novel fluorophore combinations improve fluorescence laparoscopic detection of metastatic pancreatic cancer in orthotopic mouse models.

PubMed

Metildi, Cristina A; Kaushal, Sharmeela; Lee, Claudia; Hardamon, Chanae R; Snyder, Cynthia S; Luiken, George A; Talamini, Mark A; Hoffman, Robert M; Bouvet, Michael

2012-06-01

The aim of this study was to improve fluorescence laparoscopy of pancreatic cancer in an orthotopic mouse model with the use of a light-emitting diode (LED) light source and optimal fluorophore combinations. Human pancreatic cancer models were established with fluorescent FG-RFP, MiaPaca2-GFP, BxPC-3-RFP, and BxPC-3 cancer cells implanted in 6-week-old female athymic mice. Two weeks postimplantation, diagnostic laparoscopy was performed with a Stryker L9000 LED light source or a Stryker X8000 xenon light source 24 hours after tail-vein injection of CEA antibodies conjugated with Alexa 488 or Alexa 555. Cancer lesions were detected and localized under each light mode. Intravital images were also obtained with the OV-100 Olympus and Maestro CRI Small Animal Imaging Systems, serving as a positive control. Tumors were collected for histologic analysis. Fluorescence laparoscopy with a 495-nm emission filter and an LED light source enabled real-time visualization of the fluorescence-labeled tumor deposits in the peritoneal cavity. The simultaneous use of different fluorophores (Alexa 488 and Alexa 555), conjugated to antibodies, brightened the fluorescence signal, enhancing detection of submillimeter lesions without compromising background illumination. Adjustments to the LED light source permitted simultaneous detection of tumor lesions of different fluorescent colors and surrounding structures with minimal autofluorescence. Using an LED light source with adjustments to the red, blue, and green wavelengths, it is possible to simultaneously identify tumor metastases expressing fluorescent proteins of different wavelengths, which greatly enhanced the signal without compromising background illumination. Development of this fluorescence laparoscopy technology for clinical use can improve staging and resection of pancreatic cancer. Copyright © 2012 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

Determinants of Light and Intermittent Smoking in the U.S.: Results from Three Pooled National Health Surveys

PubMed Central

Reyes-Guzman, Carolyn M.; Pfeiffer, Ruth M.; Lubin, Jay; Freedman, Neal D.; Cleary, Sean D.; Levine, Paul H.; Caporaso, Neil E.

2016-01-01

Background Light and/or intermittent smokers have been the fastest growing segment of cigarette smokers in the U.S. over the past two decades. Defining their behavioral characteristics is a critical public health priority. Materials and Methods Our sample included 78,229 U.S. adults from three pooled contemporary population-based surveys: the 2012 NHIS, 2012 NSDUH, and 2011-2012 NHANES. We classified current smokers into four categories (light and intermittent [LITS], light-daily, heavier-intermittent and heavier-daily) and assessed smoking behaviors, illicit drug use, and mental health indicators using weighted analyses. Results Analyses associated smoking categories with nicotine dependence, age of smoking initiation, race/ethnicity and other demographic and behavioral factors. Compared to heavier-daily smokers, smokers who were LITS were most likely to have mild or no nicotine dependence (weighted odds ratio [OR] = 16.92, 95% confidence interval [CI] 13.10-21.85), to start smoking cigarettes regularly after age 21 (OR = 3.42, 95% CI 2.84-4.12), and to be Hispanic (OR = 5.38, 95% CI 4.38-6.61). Additional significant results were found for other categories of smokers. Conclusion Based on pooled data from three large national surveys, light and/or intermittent smokers differed in smoking, drug use and mental health behaviors from heavier-daily, former and never smokers. Notable differences by level of smoking frequency and intensity were observed for nicotine dependence, age of smoking initiation and race/ethnicity. Impact Our results may help focus preventive measures and policies for the growing number of light and/or intermittent smokers in the U.S. because smoking patterns vary by behavioral and socioeconomic factors. PMID:27760782

MRI of Retinal Free Radical Production With Laminar Resolution In Vivo

PubMed Central

Berkowitz, Bruce A.; Lewin, Alfred S.; Biswal, Manas R.; Bredell, Bryce X.; Davis, Christopher; Roberts, Robin

2016-01-01

Purpose Recent studies have suggested the hypothesis that quench-assisted 1/T1 magnetic resonance imaging (MRI) measures free radical production with laminar resolution in vivo without the need of a contrast agent. Here, we test this hypothesis further by examining the spatial and detection sensitivity of quench-assisted 1/T1 MRI to strain, age, or retinal cell layer-specific genetic manipulations. Methods We studied: adult wild-type mice; mice at postnatal day 7 (P7); cre dependent retinal pigment epithelium (RPE)-specific MnSOD knockout mice; doxycycline-treated Sod2flox/flox mice lacking the cre transgene; and α-transducin knockout (Gnat1−/−) mice on a C57Bl/6 background. Transretinal 1/T1 profiles were mapped in vivo in the dark without or with antioxidant treatment, or followed by light exposure. We calibrated profiles spatially using optical coherence tomography. Results Dark-adapted RPE-specific MnSOD knockout mice had greater than normal 1/T1 in the RPE and outer nuclear layers that was corrected to wild-type levels by antioxidant treatment. Dark and light Gnat1−/− mice also had greater than normal outer retinal 1/T1 values. In adult wild-type mice, dark values of 1/T1 in the ellipsoid region and in the outer segment were suppressed by 13 minutes of light. By 29 minutes of light, 1/T1 reduction extended to the outer nuclear layer. Gnat1−/− mice demonstrated a faster light-evoked suppression of 1/T1 values in the outer retina. In P7 mice, transretinal 1/T1 profiles were the same in dark and light. Conclusions Quench-assisted MRI has the laminar resolution and detection sensitivity to evaluate normal and pathologic production of free radicals in vivo. PMID:26886890

Unravelling the molecular basis for light modulated cellulase gene expression - the role of photoreceptors in Neurospora crassa

PubMed Central

2012-01-01

Background Light represents an important environmental cue, which exerts considerable influence on the metabolism of fungi. Studies with the biotechnological fungal workhorse Trichoderma reesei (Hypocrea jecorina) have revealed an interconnection between transcriptional regulation of cellulolytic enzymes and the light response. Neurospora crassa has been used as a model organism to study light and circadian rhythm biology. We therefore investigated whether light also regulates transcriptional regulation of cellulolytic enzymes in N. crassa. Results We show that the N. crassa photoreceptor genes wc-1, wc-2 and vvd are involved in regulation of cellulase gene expression, indicating that this phenomenon is conserved among filamentous fungi. The negative effect of VVD on production of cellulolytic enzymes is thereby accomplished by its role in photoadaptation and hence its function in White collar complex (WCC) formation. In contrast, the induction of vvd expression by the WCC does not seem to be crucial in this process. Additionally, we found that WC-1 and WC-2 not only act as a complex, but also have individual functions upon growth on cellulose. Conclusions Genome wide transcriptome analysis of photoreceptor mutants and evaluation of results by analysis of mutant strains identified several candidate genes likely to play a role in light modulated cellulase gene expression. Genes with functions in amino acid metabolism, glycogen metabolism, energy supply and protein folding are enriched among genes with decreased expression levels in the wc-1 and wc-2 mutants. The ability to properly respond to amino acid starvation, i. e. up-regulation of the cross pathway control protein cpc-1, was found to be beneficial for cellulase gene expression. Our results further suggest a contribution of oxidative depolymerization of cellulose to plant cell wall degradation in N. crassa. PMID:22462823

Color and illuminance level of lighting can modulate willingness to eat bell peppers.

PubMed

Hasenbeck, Aimee; Cho, Sungeun; Meullenet, Jean-François; Tokar, Tonya; Yang, Famous; Huddleston, Elizabeth A; Seo, Han-Seok

2014-08-01

Food products are often encountered under colored lighting, particularly in restaurants and retail stores. However, relatively little attention has been paid to whether the color of ambient lighting can affect consumers' motivation for consumption. This study aimed to determine whether color (Experiment 1) and illuminance level (Experiment 2) of lighting can influence consumers' liking of appearance and their willingness to eat bell peppers. For red, green, and yellow bell peppers, yellow and blue lighting conditions consistently increased participants' liking of appearance the most and the least, respectively. Participants' willingness to consume bell peppers increased the most under yellow lighting and the least under blue lighting. In addition, a dark condition (i.e. low level of lighting illuminance) decreased liking of appearance and willingness to eat the bell peppers compared to a bright condition (i.e. high level of lighting illuminance). Our findings demonstrate that lighting color and illuminance level can influence consumers' hedonic impression and likelihood to consume bell peppers. Furthermore, the influences of color and illuminance level of lighting appear to be dependent on the surface color of bell peppers. © 2013 Society of Chemical Industry.

Research on starlight hardware-in-the-loop simulator

NASA Astrophysics Data System (ADS)

Zhang, Ying; Gao, Yang; Qu, Huiyang; Liu, Dongfang; Du, Huijie; Lei, Jie

2016-10-01

The starlight navigation is considered to be one of the most important methods for spacecraft navigation. Starlight simulation system is a high-precision system with large fields of view, designed to test the starlight navigation sensor performance on the ground. A complete hardware-in-the-loop simulation of the system has been built. The starlight simulator is made up of light source, light source controller, light filter, LCD, collimator and control computer. LCD is the key display component of the system, and is installed at the focal point of the collimator. For the LCD cannot emit light itself, so light source and light source power controller is specially designed for the brightness demanded by the LCD. Light filter is designed for the dark background which is also needed in the simulation.

The hard x-ray imager (HXI) onboard ASTRO-H

NASA Astrophysics Data System (ADS)

Nakazawa, Kazuhiro; Sato, Goro; Kokubun, Motohide; Enoto, Teruaki; Fukazawa, Yasushi; Hagino, Kouichi; Harayama, Atsushi; Hayashi, Katsuhiro; Kataoka, Jun; Katsuta, Junichiro; Laurent, Philippe; Lebrun, François; Limousin, Olivier; Makishima, Kazuo; Mizuno, Tsunefumi; Mori, Kunishiro; Nakamori, Takeshi; Nakano, Toshio; Noda, Hirofumi; Odaka, Hirokazu; Ohno, Masanori; Ohta, Masayuki; Saito, Shinya; Sato, Rie; Tajima, Hiroyasu; Takahashi, Hiromitsu; Takahashi, Tadayuki; Takeda, Shin'ichiro; Terada, Yukikatsu; Uchiyama, Hideki; Uchiyama, Yasunobu; Watanabe, Shin; Yamaoka, Kazutaka; Yatsu, Yoichi; Yuasa, Takayuki

2016-07-01

Hitomi X-ray observatory launched in 17 February 2016 had a hard X-ray imaging spectroscopy system made of two hard X-ray imagers (HXIs) coupled with two hard X-ray telescopes (HXTs). With 12 m focal length, they provide fine (2' half-power diameter; HPD) imaging spectroscopy at 5 to 80 keV. The HXI main imagers are made of 4 layers of Si and a CdTe semiconductor double-sided strip detectors, stacked to enhance detection efficiency as well as to enable photon interaction-depth sensing. Active shield made of 9 BGO scintillators surrounds the imager to provide with low background. Following the deployment of the Extensible Optical Bench (EOB) on 28 February, the HXI was gradually turned on. Two imagers successfully started observation on 14 March, and was operational till the incident lead to Hitomo loss, on 26 March. All detector channels, 1280 ch of imager and 11 channel of active shields and others each, worked well and showed performance consistent with those seen on ground. From the first light observation of G21.5-0.9 and the following Crab observations, 5-80 keV energy coverage and good detection efficiency were confirmed. With blank sky observations, we checked our background level. In some geomagnetic region, strong background continuum, presumably caused by trapped electron with energy 100 keV, is seen. But by cutting the high-background time-intervals, the background became significantly lower, typically with 1-3 x 10-4 counts s-1 keV-1 cm-2 (here cm2 is shown with detector geometrical area). Above 30 keV, line and continuum emission originating from activation of CdTe was significantly seen, though the level of 1-4 x 10-4 counts s-1 keV-1 cm-2 is still comparable to those seen in NuSTAR. By comparing the effective area and background rate, preliminary analysis shows that the HXI had a statistical sensitivity similar to NuSTAR for point sources, and more than twice better for largely extended sources.

An exponential filter model predicts lightness illusions

PubMed Central

Zeman, Astrid; Brooks, Kevin R.; Ghebreab, Sennay

2015-01-01

Lightness, or perceived reflectance of a surface, is influenced by surrounding context. This is demonstrated by the Simultaneous Contrast Illusion (SCI), where a gray patch is perceived lighter against a black background and vice versa. Conversely, assimilation is where the lightness of the target patch moves toward that of the bounding areas and can be demonstrated in White's effect. Blakeslee and McCourt (1999) introduced an oriented difference-of-Gaussian (ODOG) model that is able to account for both contrast and assimilation in a number of lightness illusions and that has been subsequently improved using localized normalization techniques. We introduce a model inspired by image statistics that is based on a family of exponential filters, with kernels spanning across multiple sizes and shapes. We include an optional second stage of normalization based on contrast gain control. Our model was tested on a well-known set of lightness illusions that have previously been used to evaluate ODOG and its variants, and model lightness values were compared with typical human data. We investigate whether predictive success depends on filters of a particular size or shape and whether pooling information across filters can improve performance. The best single filter correctly predicted the direction of lightness effects for 21 out of 27 illusions. Combining two filters together increased the best performance to 23, with asymptotic performance at 24 for an arbitrarily large combination of filter outputs. While normalization improved prediction magnitudes, it only slightly improved overall scores in direction predictions. The prediction performance of 24 out of 27 illusions equals that of the best performing ODOG variant, with greater parsimony. Our model shows that V1-style orientation-selectivity is not necessary to account for lightness illusions and that a low-level model based on image statistics is able to account for a wide range of both contrast and assimilation effects. PMID:26157381

Spallation backgrounds in Super-Kamiokande are made in muon-induced showers

NASA Astrophysics Data System (ADS)

Li, Shirley Weishi; Beacom, John F.

2015-05-01

Crucial questions about solar and supernova neutrinos remain unanswered. Super-Kamiokande has the exposure needed for progress, but detector backgrounds are a limiting factor. A leading component is the beta decays of isotopes produced by cosmic-ray muons and their secondaries, which initiate nuclear spallation reactions. Cuts of events after and surrounding muon tracks reduce this spallation decay background by ≃ 90 % (at a cost of ≃ 20 % deadtime), but its rate at 6-18 MeV is still dominant. A better way to cut this background was suggested in a Super-Kamiokande paper by Bays et al. [Phys. Rev. D 85, 052007 (2012)] on a search for the diffuse supernova neutrino background. They found that spallation decays above 16 MeV were preceded near the same location by a peak in the apparent Cherenkov light profile from the muon; a more aggressive cut was applied to a limited section of the muon track, leading to decreased background without increased deadtime. We put their empirical discovery on a firm theoretical foundation. We show that almost all spallation decay isotopes are produced by muon-induced showers and that these showers are rare enough and energetic enough to be identifiable. This is the first such demonstration for any detector. We detail how the physics of showers explains the peak in the muon Cherenkov light profile and other Super-K observations. Our results provide a physical basis for practical improvements in background rejection that will benefit multiple studies. For solar neutrinos, in particular, it should be possible to dramatically reduce backgrounds at energies as low as 6 MeV.

V+jets Background and Systematic Uncertainties in Top Quark Analyses

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

Adomeit, Stefanie; Peters, Reinhild Yvonne

2014-12-01

Vector boson production in association with jets is an important process to test perturbative quantum chromodynamics and also a background process in top quark analyses. Measurements on vector boson production in association with light and heavy flavour jets are presented, performed by the D0 and CDF collaborations at the Tevatron as well as the ATLAS and CMS experiments at LHC. Techniques applied in top quark analyses to estimate the vector boson+jets background are also discussed.

Slowing down the speed of light using an electromagnetically-induced-transparency mechanism in a modified reservoir

NASA Astrophysics Data System (ADS)

Liu, Ronggang; Liu, Tong; Wang, Yingying; Li, Yujie; Gai, Bingzheng

2017-11-01

We propose an effective method to achieve extremely slow light by using both the mechanism of electromagnetically induced transparency (EIT) and the localization of a coupled cavity waveguide (CCW). Based on quantum mechanics theory and the dispersion relation of a CCW, we derive a group-velocity formula that reveals both the effects of the EIT and CCW. Results show that ultralow light velocity at the order of several meters per second or even static light, could be obtained feasibly. In comparison with the EIT mechanism in a background of vacuum, this proposed method is more effective and realistic to achieve extremely slow light. And it exhibits potential values in the field of light storage.

Light and Color in Nature and Art

NASA Astrophysics Data System (ADS)

Williamson, Samuel J.; Cummins, Herman Z.

1983-02-01

An introduction to the science of light and color and its applications to photography, art, natural phenomena, and other related areas. Explains the origin of phenomena commonly encountered in nature and art, emphasizing the physical aspects but also touching on aspects of physiology and psychology that directly influence how visual images are perceived. Covers the effect of mixing color, the notion of color spaces, how atoms and molecules affect light, how light can be measured, the effect of using a lens, and many other topics. Requires little or no mathematical background. Includes questions and references for further reading.

A Simplified, Low-Cost Method for Polarized Light Microscopy

PubMed Central

Maude, Richard J.; Buapetch, Wanchana; Silamut, Kamolrat

2009-01-01

Malaria pigment is an intracellular inclusion body that appears in blood and tissue specimens on microscopic examination and can help in establishing the diagnosis of malaria. In simple light microscopy, it can be difficult to discern from cellular background and artifacts. It has long been known that if polarized light microscopy is used, malaria pigment can be much easier to distinguish. However, this technique is rarely used because of the need for a relatively costly polarization microscope. We describe a simple and economical technique to convert any standard light microscope suitable for examination of malaria films into a polarization microscope. PMID:19861611

Luminance requirements for lighted signage

NASA Astrophysics Data System (ADS)

Freyssinier, Jean Paul; Narendran, Nadarajah; Bullough, John D.

2006-08-01

Light-emitting diode (LED) technology is presently targeted to displace traditional light sources in backlighted signage. The literature shows that brightness and contrast are perhaps the two most important elements of a sign that determine its attention-getting capabilities and its legibility. Presently, there are no luminance standards for signage, and the practice of developing brighter signs to compete with signs in adjacent businesses is becoming more commonplace. Sign luminances in such cases may far exceed what people usually need for identifying and reading a sign. Furthermore, the practice of higher sign luminance than needed has many negative consequences, including higher energy use and light pollution. To move toward development of a recommendation for lighted signage, several laboratory human factors evaluations were conducted. A scale model of a storefront was used to present human subjects with a typical red channel-letter sign at luminances ranging from 8 cd/m2 to 1512 cd/m2 under four background luminances typical of nighttime outdoor and daytime inside-mall conditions (1, 100, 300, 1000 cd/m2), from three scaled viewing distances (30, 60, 340 ft), and either in isolation or adjacent to two similar signs. Subjects rated the brightness, acceptability, and ease of reading of the test sign for each combination of sign and background luminances and scaled viewing distances.

Passive ranging redundancy reduction in diurnal weather conditions

NASA Astrophysics Data System (ADS)

Cha, Jae H.; Abbott, A. Lynn; Szu, Harold H.

2013-05-01

Ambiguity in binocular ranging (David Marr's paradox) may be resolved by using two eyes moving from side to side behind an optical bench while integrating multiple views. Moving a head from left to right with one eye closed can also help resolve the foreground and background range uncertainty. That empirical experiment implies redundancy in image data, which may be reduced by adopting a 3-D camera imaging model to perform compressive sensing. Here, the compressive sensing concept is examined from the perspective of redundancy reduction in images subject to diurnal and weather variations for the purpose of resolving range uncertainty at all weather conditions such as the dawn or dusk, the daytime with different light level or the nighttime at different spectral band. As an example, a scenario at an intersection of a country road at dawn/dusk is discussed where the location of the traffic signs needs to be resolved by passive ranging to answer whether it is located on the same side of the road or the opposite side, which is under the influence of temporal light/color level variation. A spectral band extrapolation via application of Lagrange Constrained Neural Network (LCNN) learning algorithm is discussed to address lost color restoration at dawn/dusk. A numerical simulation is illustrated along with the code example.

The diffuse gamma-ray background, light element abundances, and signatures of early massive star formation

NASA Technical Reports Server (NTRS)

Silk, Joseph; Schramm, David N.

1992-01-01

Attention is drawn to a potentially observable flux of diffuse extragalactic gamma rays produced by inelastic cosmic-ray interactions that is inevitably a by-product of spallation-synthesized Be. The epoch of cosmic ray-induced Population II light element nucleosynthesis is constrained to be at redshift greater than 0.5. A spectral feature in the diffuse extragalactic gamma-ray background with amplitude 0.1 above 10 MeV is predicted if the Be is synthesized at z less than 10. The possibility is discussed that the cosmic-ray flux responsible for Population II Be and B synthesis may be associated with a precursor hypothesized Population III.

New color-shifting security devices

NASA Astrophysics Data System (ADS)

Moia, Franco

2004-06-01

The unbroken global increase of forgery and counterfeiting of valuable documents and products steadily requires improved types of optical security devices. Hence, the "security world" is actively seeking for new features which meet high security standards, look attractively and allow easy recognition. One special smart security device created by ROLIC's technology represents a cholesteric device combined with a phase image. On tilting, such devices reveal strong color shifts which are clearly visible to the naked eye. The additional latent image is invisible under normal lighting conditions but can be revealed to human eyes by means of a simple, commercially available linear sheet polarizer. Based on our earlier work, first published in 1981, we now have developed phase change guest-host devices combined with dye-doped cholesteric material for application in new security features. ROLIC has developed sophisticated material systems of cross-linkable cholesteric liquid crystals and suitable cross-linkable dyes which allow to create outstanding cholesteric color-shifting effects not only on light absorbing dark backgrounds but also on bright or even white backgrounds preserving the circularly polarizing state. The new security devices combine unambiguously 1st and 2nd level inspection features and show brilliant colors on black as well as on white substrates. On tilting, the security devices exhibit remarkable color shifts while the integrated hidden images can be revealed by use of a sheet polarizer. Furthermore, due to its very thin material layers, even demanding applications, such as on banknotes can be considered.

The photocurrent, noise and spectral sensitivity of rods of the monkey Macaca fascicularis.

PubMed Central

Baylor, D A; Nunn, B J; Schnapf, J L

1984-01-01

Visual transduction in rods of the cynomolgus monkey, Macaca fascicularis, was studied by recording membrane current from single outer segments projecting from small pieces of retina. Light flashes evoked transient outward-going photocurrents with saturating amplitudes of up to 34 pA. A flash causing twenty to fifty photoisomerizations gave a response of half the saturating amplitude. The response-stimulus relation was of the form 1-e-x where x is flash strength. The response to a dim flash usually had a time to peak of 150-250 ms and resembled the impulse response of a series of six low-pass filters. From the average spectral sensitivity of ten rods the rhodopsin was estimated to have a peak absorption near 491 nm. The spectral sensitivity of the rods was in good agreement with the average human scotopic visibility curve determined by Crawford (1949), when the human curve was corrected for lens absorption and self-screening of rhodopsin. Fluctuations in the photocurrent evoked by dim lights were consistent with a quantal event about 0.7 pA in peak amplitude. A steady light causing about 100 photoisomerizations s-1 reduced the flash sensitivity to half the dark-adapted value. At higher background levels the rod rapidly saturated. These results support the idea that dim background light desensitizes human scotopic vision by a mechanism central to the rod outer segments while scotopic saturation may occur within the outer segments. Recovery of the photocurrent after bright flashes was marked by quantized step-like events. The events had the properties expected if bleached rhodopsin in the disks occasionally caused an abrupt blockage of the dark current over about one-twentieth of the length of the outer segment. It is suggested that superposition of these events after bleaching may contribute to the threshold elevation measured psychophysically. The current in darkness showed random fluctuations which disappeared in bright light. The continuous component of the noise had a variance of about 0.03 pA2 and a power spectrum that fell to half near 3 Hz. A second component, consisting of discrete events resembling single-photon responses, was estimated to occur at a rate of 0.006 s-1. It is suggested that the continuous component of the noise may be removed from scotopic vision by a thresholding operation near the rod output. PMID:6512705

The photocurrent, noise and spectral sensitivity of rods of the monkey Macaca fascicularis.

PubMed

Baylor, D A; Nunn, B J; Schnapf, J L

1984-12-01

Visual transduction in rods of the cynomolgus monkey, Macaca fascicularis, was studied by recording membrane current from single outer segments projecting from small pieces of retina. Light flashes evoked transient outward-going photocurrents with saturating amplitudes of up to 34 pA. A flash causing twenty to fifty photoisomerizations gave a response of half the saturating amplitude. The response-stimulus relation was of the form 1-e-x where x is flash strength. The response to a dim flash usually had a time to peak of 150-250 ms and resembled the impulse response of a series of six low-pass filters. From the average spectral sensitivity of ten rods the rhodopsin was estimated to have a peak absorption near 491 nm. The spectral sensitivity of the rods was in good agreement with the average human scotopic visibility curve determined by Crawford (1949), when the human curve was corrected for lens absorption and self-screening of rhodopsin. Fluctuations in the photocurrent evoked by dim lights were consistent with a quantal event about 0.7 pA in peak amplitude. A steady light causing about 100 photoisomerizations s-1 reduced the flash sensitivity to half the dark-adapted value. At higher background levels the rod rapidly saturated. These results support the idea that dim background light desensitizes human scotopic vision by a mechanism central to the rod outer segments while scotopic saturation may occur within the outer segments. Recovery of the photocurrent after bright flashes was marked by quantized step-like events. The events had the properties expected if bleached rhodopsin in the disks occasionally caused an abrupt blockage of the dark current over about one-twentieth of the length of the outer segment. It is suggested that superposition of these events after bleaching may contribute to the threshold elevation measured psychophysically. The current in darkness showed random fluctuations which disappeared in bright light. The continuous component of the noise had a variance of about 0.03 pA2 and a power spectrum that fell to half near 3 Hz. A second component, consisting of discrete events resembling single-photon responses, was estimated to occur at a rate of 0.006 s-1. It is suggested that the continuous component of the noise may be removed from scotopic vision by a thresholding operation near the rod output.

Noise and light exposures for extremely low birth weight newborns during their stay in the neonatal intensive care unit.

PubMed

Lasky, Robert E; Williams, Amber L

2009-02-01

The objectives of this study were to characterize noise and light levels for extremely low birth weight newborns throughout their stay in the NICU, evaluate factors influencing noise and light levels, and determine whether exposures meet recommendations from the American Academy of Pediatrics. Sound and light were measured inside the beds of extremely low birth weight newborns (n = 22) from birth to discharge. Measurements were recorded for 20 consecutive hours weekly from birth until 36 weeks' postmenstrual age, biweekly until 40 weeks, and every 4 weeks thereafter. Clinical variables including bed type and method of respiratory support were recorded at each session. Age-related changes in respiratory support and bed type explained the weekly increase of 0.22 dB in sound level and 3.67 lux in light level. Old incubators were the noisiest bed types, and new incubators were the quietest. Light levels were significantly higher in open beds than in incubators. The variations in noise and light levels over time were greatest for open beds. Noise and light levels were much less affected by respiratory support in incubators compared with open beds. A typical extremely low birth weight neonate was exposed to noise levels averaging 56.44 dB(A) and light levels averaging 70.56 lux during their stay from 26 to 42 weeks' postmenstrual age in the NICU. Noise levels were rarely within American Academy of Pediatrics recommendations (5.51% of the time), whereas light levels almost always met recommendations (99.37% of the time). Bed type and respiratory support explained differences in noise and light levels that extremely low birth weight newborns experience during their hospital stay. Noise levels exceeded recommendations, although evidence supporting those recommendations is lacking. Well-designed intervention studies are needed to determine the effects of noise reduction on the development of extremely low birth weight newborns.

40 CFR 61.133 - Standard: Light-oil sumps.

Code of Federal Regulations, 2010 CFR

2010-07-01

... maintain a vent on the light-oil sump cover. Each vent pipe must be equipped with a water leg seal, a... more than 500 ppm above a background concentration, as measured by Method 21, a leak is detected. (2) If visible defects such as gaps in sealing materials are observed during a visual inspection, a leak...

75 FR 80547 - Carolina Power & Light Company, Shearon Harris Nuclear Power Plant, Unit No. 1; Exemption

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-22

..., Shearon Harris Nuclear Power Plant, Unit No. 1; Exemption 1.0 Background Carolina Power & Light Company... operation of the Shearon Harris Nuclear Power Plant (HNP), Unit 1. The license provides, among other things... request to generically extend the rule's compliance date for all operating nuclear power plants, but noted...

Optimization of Enzyme-Substrate Pairing for Bioluminescence Imaging of Gene Transfer Using Renilla and Gaussia Luciferases

PubMed Central

Kimura, Takahiro; Hiraoka, Kei; Kasahara, Noriyuki; Logg, Christopher R.

2010-01-01

Background Bioluminescence imaging (BLI) permits the noninvasive quantitation and localization of transduction and expression by gene transfer vectors. The tendency of tissue to attenuate light in the optical region, however, limits the sensitivity of BLI. Improvements in light output from bioluminescent reporter systems would allow the detection of lower levels of expression, smaller numbers of cells and expression from deeper and more attenuating tissues within an animal. Methods With the goal of identifying substrates that allow improved sensitivity with Renilla luciferase (RLuc) and Gaussia luciferase (GLuc) reporter genes, we evaluated native coelenterazine and three of its most promising derivatives in BLI of cultured cells transduced with retroviral vectors encoding these reporters. Of the eight enzyme-substrate pairs tested, the two that performed best were further evaluated in mice to compare their effectiveness for imaging vector-modified cells in live animals. Results In cell culture, we observed striking differences in luminescence levels from the various enzyme-substrate combinations and found that the two luciferases exhibited markedly distinct abilities to generate light with the substrates. The most effective pairs were RLuc with the synthetic coelenterazine derivative ViviRen, and GLuc with native coelenterazine. In animals, these two pairs allowed similar detection sensitivities, which were 8–15 times higher than that of the prototypical RLuc-native coelenterazine combination. Conclusions Our results demonstrate that substrate selection can dramatically influence the detection sensitivity of RLuc and GLuc and that appropriate selection of substrate can greatly improve the performance of reporter genes encoding these enzymes for monitoring gene transfer by BLI. PMID:20527045

Mixed-Forest Species Establishment in a Monodominant Forest in Central Africa: Implications for Tropical Forest Invasibility

PubMed Central

Peh, Kelvin S.-H.; Sonké, Bonaventure; Séné, Olivier; Djuikouo, Marie-Noël K.; Nguembou, Charlemagne K.; Taedoumg, Hermann; Begne, Serge K.; Lewis, Simon L.

2014-01-01

Background Traits of non-dominant mixed-forest tree species and their synergies for successful co-occurrence in monodominant Gilbertiodendron dewevrei forest have not yet been investigated. Here we compared the tree species diversity of the monodominant forest with its adjacent mixed forest and then determined which fitness proxies and life history traits of the mixed-forest tree species were most associated with successful co-existence in the monodominant forest. Methodology/Principal Findings We sampled all trees (diameter in breast height [dbh]≥10 cm) within 6×1 ha topographically homogenous areas of intact central African forest in SE Cameroon, three independent patches of G. dewevrei-dominated forest and three adjacent areas (450–800 m apart). Monodominant G. dewevrei forest had lower sample-controlled species richness, species density and population density than its adjacent mixed forest in terms of stems with dbh≥10 cm. Analysis of a suite of population-level characteristics, such as relative abundance and geographical distribution, and traits such as wood density, height, diameter at breast height, fruit/seed dispersal mechanism and light requirement–revealed after controlling for phylogeny, species that co-occur with G. dewevrei tend to have higher abundance in adjacent mixed forest, higher wood density and a lower light requirement. Conclusions/Significance Our results suggest that certain traits (wood density and light requirement) and population-level characteristics (relative abundance) may increase the invasibility of a tree species into a tropical closed-canopy system. Such knowledge may assist in the pre-emptive identification of invasive tree species. PMID:24844914

Light Levels, Refractive Development, and Myopia – a Speculative Review

PubMed Central

Norton, Thomas T.; Siegwart, John T.

2013-01-01

Recent epidemiological evidence in children indicates that time spent outdoors is protective against myopia. Studies in animal models (chick, macaque, tree shrew) have found that light levels (similar to being in the shade outdoors) that are mildly elevated compared to indoor levels, slow form-deprivation myopia and (in chick and tree shrew) lens-induced myopia. Normal chicks raised in low light levels (50 lux) with a circadian light on/off cycle often develop spontaneous myopia. We propose a model in which the ambient illuminance levels produce a continuum of effects on normal refractive development and the response to myopiagenic stimuli such that low light levels favor myopia development and elevated levels are protective. Among possible mechanisms, elevation of retinal dopamine activity seems the most likely. Inputs from intrinsically-photosensitive retinal ganglion cells (ipRGCs) at elevated light levels may be involved, providing additional activation of retinal dopaminergic pathways. PMID:23680160

Reduction of time-resolved space-based CCD photometry developed for MOST Fabry Imaging data*

NASA Astrophysics Data System (ADS)

Reegen, P.; Kallinger, T.; Frast, D.; Gruberbauer, M.; Huber, D.; Matthews, J. M.; Punz, D.; Schraml, S.; Weiss, W. W.; Kuschnig, R.; Moffat, A. F. J.; Walker, G. A. H.; Guenther, D. B.; Rucinski, S. M.; Sasselov, D.

2006-04-01

The MOST (Microvariability and Oscillations of Stars) satellite obtains ultraprecise photometry from space with high sampling rates and duty cycles. Astronomical photometry or imaging missions in low Earth orbits, like MOST, are especially sensitive to scattered light from Earthshine, and all these missions have a common need to extract target information from voluminous data cubes. They consist of upwards of hundreds of thousands of two-dimensional CCD frames (or subrasters) containing from hundreds to millions of pixels each, where the target information, superposed on background and instrumental effects, is contained only in a subset of pixels (Fabry Images, defocused images, mini-spectra). We describe a novel reduction technique for such data cubes: resolving linear correlations of target and background pixel intensities. This step-wise multiple linear regression removes only those target variations which are also detected in the background. The advantage of regression analysis versus background subtraction is the appropriate scaling, taking into account that the amount of contamination may differ from pixel to pixel. The multivariate solution for all pairs of target/background pixels is minimally invasive of the raw photometry while being very effective in reducing contamination due to, e.g. stray light. The technique is tested and demonstrated with both simulated oscillation signals and real MOST photometry.

Vacuum ultraviolet imagery of the Virgo cluster region

NASA Astrophysics Data System (ADS)

Onaka, T.; Tanaka, W.; Watanabe, T.; Watanabe, J.; Yamaguchi, A.; Nakagiri, M.; Kodaira, K.; Nakano, M.; Sasaki, M.; Tsujimura, T.; Yamashita, K.

1989-07-01

The results are reported of an experiment using the UV imager aboard an attitude-controlled S520 type sounding rocket. The total UV fluxes of galaxies in the Virgo Cluster as well as the flux level of the diffuse UV background around the cluster were measured. The data on NGC 4486 and NGC 4472 confirm the variation in the degree of the 'turnup' below 200 nm in the energy spectrum of the total light of elliptical galaxies. At two-color diagram of galaxies of visual/near-UV/vacuum UV indicates that colors of spiral galaxies are distributed within a strip and well-correlated with the morphological type, while elliptical galaxies are located differently from spiral galaxies.

SUBGR: A Program to Generate Subgroup Data for the Subgroup Resonance Self-Shielding Calculation

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

Kim, Kang Seog

2016-06-06

The Subgroup Data Generation (SUBGR) program generates subgroup data, including levels and weights from the resonance self-shielded cross section table as a function of background cross section. Depending on the nuclide and the energy range, these subgroup data can be generated by (a) narrow resonance approximation, (b) pointwise flux calculations for homogeneous media; and (c) pointwise flux calculations for heterogeneous lattice cells. The latter two options are performed by the AMPX module IRFFACTOR. These subgroup data are to be used in the Consortium for Advanced Simulation of Light Water Reactors (CASL) neutronic simulator MPACT, for which the primary resonance self-shieldingmore » method is the subgroup method.« less

Conceptual framework to ensure water security in Ukraine

NASA Astrophysics Data System (ADS)

Gadzalo, Yaroslav; Romashchenko, Mykhailo; Yatsiuk, Mykhailo

2018-02-01

As a result of global climate change against the background of natural water supply deterioration and river water content reductions, nowadays Ukraine is facing the problem of environmental degradation of river basins. In light of this, we suggest that achieving an acceptable level of water security in Ukraine should be defined as the strategic objective of national water policy. The state of national water security should be evaluated by its progress in certain sectors. The basic principles of the new water policy of Ukraine are supposed to be represented in Water Strategy of Ukraine. Integrated water management by the basin principle should serve as the main tool for achieving the objectives of water security.

Identification and mitigation of stray laser light in the Thomson scattering system on the Madison Symmetric Torus (MST).

PubMed

Jacobson, C M; Borchardt, M T; Den Hartog, D J; Falkowski, A F; Morton, L A; Thomas, M A

2016-11-01

The Thomson scattering diagnostic on the Madison Symmetric Torus (MST) records excessive levels of stray Nd:YAG laser light. Stray light saturates the 1064 nm spectral channel in all polychromators, which prevents absolute electron density measurements via Rayleigh scattering calibration. Furthermore, stray light contaminates adjacent spectral channels for r/a ≥ 0.75, which renders the diagnostic unable to make electron temperature measurements at these radii. In situ measurements of stray light levels during a vacuum vessel vent are used to identify stray light sources and strategies for reduction of stray light levels. Numerical modeling using Zemax OpticStudio supports these measurements. The model of the vacuum vessel and diagnostic includes synthetic collection optics to enable direct comparison of measured and simulated stray light levels. Modeling produces qualitatively similar stray light distributions to MST measurements, and quantifies the mitigation effects of stray light mitigation strategies prior to implementation.

Identification and mitigation of stray laser light in the Thomson scattering system on the Madison Symmetric Torus (MST)

NASA Astrophysics Data System (ADS)

Jacobson, C. M.; Borchardt, M. T.; Den Hartog, D. J.; Falkowski, A. F.; Morton, L. A.; Thomas, M. A.

2016-11-01

The Thomson scattering diagnostic on the Madison Symmetric Torus (MST) records excessive levels of stray Nd:YAG laser light. Stray light saturates the 1064 nm spectral channel in all polychromators, which prevents absolute electron density measurements via Rayleigh scattering calibration. Furthermore, stray light contaminates adjacent spectral channels for r/a ≥ 0.75, which renders the diagnostic unable to make electron temperature measurements at these radii. In situ measurements of stray light levels during a vacuum vessel vent are used to identify stray light sources and strategies for reduction of stray light levels. Numerical modeling using Zemax OpticStudio supports these measurements. The model of the vacuum vessel and diagnostic includes synthetic collection optics to enable direct comparison of measured and simulated stray light levels. Modeling produces qualitatively similar stray light distributions to MST measurements, and quantifies the mitigation effects of stray light mitigation strategies prior to implementation.

Temporal structure in the light response of relay cells in the dorsal lateral geniculate nucleus of the cat.

PubMed Central

Funke, K; Wörgötter, F

1995-01-01

1. The spike interval pattern during the light responses of 155 on- and 81 off-centre cells of the dorsal lateral geniculate nucleus (LGN) was studied in anaesthetized and paralysed cats by the use of a novel analysis. Temporally localized interval distributions were computed from a 100 ms time window, which was shifted along the time axis in 10 ms steps, resulting in a 90% overlap between two adjacent windows. For each step the interval distribution was computed inside the time window with 1 ms resolution, and plotted as a greyscale-coded pixel line orthogonal to the time axis. For visual stimulation, light or dark spots of different size and contrast were presented with different background illumination levels. 2. Two characteristic interval patterns were observed during the sustained response component of the cells. Mainly on-cells (77%) responded with multimodal interval distributions, resulting in elongated 'bands' in the 2-dimensional time window plots. In similar situations, the interval distributions for most (71%) off-cells were rather wide and featureless. In those cases where interval bands (i.e. multimodal interval distributions) were observed for off-cells (14%), they were always much wider than for the on-cells. This difference between the on- and off-cell population was independent of the background illumination and the contrast of the stimulus. Y on-cells also tended to produce wider interval bands than X on-cells. 3. For most stimulation situations the first interval band was centred around 6-9 ms, which has been called the fundamental interval; higher order bands are multiples thereof. The fundamental interval shifted towards larger sizes with decreasing stimulus contrast. Increasing stimulus size, on the other hand, resulted in a redistribution of the intervals into higher order bands, while at the same time the location of the fundamental interval remained largely unaffected. This was interpreted as an effect of the increasing surround inhibition at the geniculate level, by which individual retinal EPSPs were cancelled. A changing level of adaptation can result in a mixed shift/redistribution effect because of the changing stimulus contrast and changing level of tonic inhibition. 4. The occurrence of interval bands is not directly related to the shape of the autocorrelation function, which can be flat, weakly oscillatory or strongly oscillatory, regardless of the interval band pattern. 5. A simple computer model was devised to account for the observed cell behaviour. The model is highly robust against parameter variations.(ABSTRACT TRUNCATED AT 400 WORDS) Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 15 PMID:7562612

Energy transport velocity in bidispersed magnetic colloids.

PubMed

Bhatt, Hem; Patel, Rajesh; Mehta, R V

2012-07-01

Study of energy transport velocity of light is an effective background for slow, fast, and diffuse light and exhibits the photonic property of the material. We report a theoretical analysis of magnetic field dependent resonant behavior in forward-backward anisotropy factor, light diffusion constant, and energy transport velocity for bidispersed magnetic colloids. A bidispersed magnetic colloid is composed of micrometer size magnetic spheres dispersed in a magnetic nanofluid consisting of magnetic nanoparticles in a nonmagnetic liquid carrier. Magnetic Mie resonances and reduction in energy transport velocity accounts for the possible delay (longer dwell time) by field dependent resonant light transport. This resonant behavior of light in bidispersed magnetic colloids suggests a novel magnetophotonic material.

Spotlight on fish: light pollution affects circadian rhythms of European perch but does not cause stress.

PubMed

Brüning, Anika; Hölker, Franz; Franke, Steffen; Preuer, Torsten; Kloas, Werner

2015-04-01

Flora and fauna evolved under natural day and night cycles. However, natural light is now enhanced by artificial light at night, particularly in urban areas. This alteration of natural light environments during the night is hypothesised to alter biological rhythms in fish, by effecting night-time production of the hormone melatonin. Artificial light at night is also expected to increase the stress level of fish, resulting in higher cortisol production. In laboratory experiments, European perch (Perca fluviatilis) were exposed to four different light intensities during the night, 0 lx (control), 1 lx (potential light level in urban waters), 10 lx (typical street lighting at night) and 100 lx. Melatonin and cortisol concentrations were measured from water samples every 3h during a 24 hour period. This study revealed that the nocturnal increase in melatonin production was inhibited even at the lowest light level of 1 lx. However, cortisol levels did not differ between control and treatment illumination levels. We conclude that artificial light at night at very low intensities may disturb biological rhythms in fish since nocturnal light levels around 1 lx are already found in urban waters. However, enhanced stress induction could not be demonstrated. Copyright © 2014 Elsevier B.V. All rights reserved.

En route to Background Independence: Broken split-symmetry, and how to restore it with bi-metric average actions

NASA Astrophysics Data System (ADS)

Becker, D.; Reuter, M.

2014-11-01

The most momentous requirement a quantum theory of gravity must satisfy is Background Independence, necessitating in particular an ab initio derivation of the arena all non-gravitational physics takes place in, namely spacetime. Using the background field technique, this requirement translates into the condition of an unbroken split-symmetry connecting the (quantized) metric fluctuations to the (classical) background metric. If the regularization scheme used violates split-symmetry during the quantization process it is mandatory to restore it in the end at the level of observable physics. In this paper we present a detailed investigation of split-symmetry breaking and restoration within the Effective Average Action (EAA) approach to Quantum Einstein Gravity (QEG) with a special emphasis on the Asymptotic Safety conjecture. In particular we demonstrate for the first time in a non-trivial setting that the two key requirements of Background Independence and Asymptotic Safety can be satisfied simultaneously. Carefully disentangling fluctuation and background fields, we employ a 'bi-metric' ansatz for the EAA and project the flow generated by its functional renormalization group equation on a truncated theory space spanned by two separate Einstein-Hilbert actions for the dynamical and the background metric, respectively. A new powerful method is used to derive the corresponding renormalization group (RG) equations for the Newton- and cosmological constant, both in the dynamical and the background sector. We classify and analyze their solutions in detail, determine their fixed point structure, and identify an attractor mechanism which turns out instrumental in the split-symmetry restoration. We show that there exists a subset of RG trajectories which are both asymptotically safe and split-symmetry restoring: In the ultraviolet they emanate from a non-Gaussian fixed point, and in the infrared they loose all symmetry violating contributions inflicted on them by the non-invariant functional RG equation. As an application, we compute the scale dependent spectral dimension which governs the fractal properties of the effective QEG spacetimes at the bi-metric level. Earlier tests of the Asymptotic Safety conjecture almost exclusively employed 'single-metric truncations' which are blind towards the difference between quantum and background fields. We explore in detail under which conditions they can be reliable, and we discuss how the single-metric based picture of Asymptotic Safety needs to be revised in the light of the new results. We shall conclude that the next generation of truncations for quantitatively precise predictions (of critical exponents, for instance) is bound to be of the bi-metric type.

Detecting Exoplanets with the New Worlds Observer: The Problem of Exozodiacal Dust

NASA Technical Reports Server (NTRS)

Roberge, A.; Noecker, M. C.; Glassman, T. M.; Oakley, P.; Turnbull, M. C.

2009-01-01

Dust coming from asteroids and comets will strongly affect direct imaging and characterization of terrestrial planets in the Habitable Zones of nearby stars. Such dust in the Solar System is called the zodiacal dust (or 'zodi' for short). Higher levels of similar dust are seen around many nearby stars, confined in disks called debris disks. Future high-contrast images of an Earth-like exoplanet will very likely be background-limited by light scattered of both the local Solar System zodi and the circumstellar dust in the extrasolar system (the exozodiacal dust). Clumps in the exozodiacal dust, which are expected in planet-hosting systems, may also be a source of confusion. Here we discuss the problems associated with imaging an Earth-like planet in the presence of unknown levels of exozodiacal dust. Basic formulae for the exoplanet imaging exposure time as function of star, exoplanet, zodi, exozodi, and telescope parameters will be presented. To examine the behavior of these formulae, we apply them to the New Worlds Observer (NWO) mission. NWO is a proposed 4-meter UV/optical/near-IR telescope, with a free flying starshade to suppress the light from a nearby star and achieve the high contrast needed for detection and characterization of a terrestrial planet in the star's Habitable Zone. We find that NWO can accomplish its science goals even if exozodiacal dust levels are typically much higher than the Solar System zodi level. Finally, we highlight a few additional problems relating to exozodiacal dust that have yet to be solved.

Design of a portable fluoroquinolone analyzer based on terbium-sensitized luminescence

NASA Astrophysics Data System (ADS)

Chen, Guoying

2007-09-01

A portable fluoroquinolone (FQ) analyzer is designed and prototyped based on terbium-sensitized luminescence (TSL). The excitation source is a 327-nm light emitting diode (LED) operated in pulsed mode; and the luminescence signal is detected by a photomultiplier tube (PMT). In comparison to a conventional xenon flashlamp, an LED is small, light, robust, and energy efficient. More importantly, its narrow emission bandwidth and low residual radiation reduce background signal. In pulse mode, an LED operates at a current 1-2 orders of magnitude lower than that of a xenon flashlamp, thus minimizing electromagnetic interference (EMI) to the detector circuitry. The PMT is gated to minimize its response to the light source. These measures lead to reduced background noise in time domain. To overcome pulse-to-pulse variation signal normalization is implemented based on individual pulse energy. Instrument operation and data processing are controlled by a computer running a custom LabVIEW program. Enrofloxacin (ENRO) is used as a model analyte to evaluate instrument performance. The integrated TSL intensity reveals a linear dependence up to 2 ppm. A 1.1-ppb limit of detection (LOD) is achieved with relative standard deviation (RSD) averaged at 5.1%. The background noise corresponds to ~5 ppb. At 19 lbs, this portable analyzer is field deployable for agriculture, environmental and clinical analyses.