LTP saturation and spatial learning disruption: effects of task variables and saturation levels.

PubMed

Barnes, C A; Jung, M W; McNaughton, B L; Korol, D L; Andreasson, K; Worley, P F

1994-10-01

The prediction that "saturation" of LTP/LTE at hippocampal synapses should impair spatial learning was reinvestigated in the light of a more specific consideration of the theory of Hebbian associative networks, which predicts a nonlinear relationship between LTP "saturation" and memory impairment. This nonlinearity may explain the variable results of studies that have addressed the effects of LTP "saturation" on behavior. The extent of LTP "saturation" in fascia dentata produced by the standard chronic LTP stimulation protocol was assessed both electrophysiologically and through the use of an anatomical marker (activation of the immediate-early gene zif268). Both methods point to the conclusion that the standard protocols used to induce LTP do not "saturate" the process at any dorsoventral level, and leave the ventral half of the hippocampus virtually unaffected. LTP-inducing, bilateral perforant path stimulation led to a significant deficit in the reversal of a well-learned spatial response on the Barnes circular platform task as reported previously, yet in the same animals produced no deficit in learning the Morris water task (for which previous results have been conflicting). The behavioral deficit was not a consequence of any after-discharge in the hippocampal EEG. In contrast, administration of maximal electroconvulsive shock led to robust zif268 activation throughout the hippocampus, enhancement of synaptic responses, occlusion of LTP produced by discrete high-frequency stimulation, and spatial learning deficits in the water task. These data provide further support for the involvement of LTP-like synaptic enhancement in spatial learning.

Multi-frame partially saturated images blind deconvolution

NASA Astrophysics Data System (ADS)

Ye, Pengzhao; Feng, Huajun; Xu, Zhihai; Li, Qi; Chen, Yueting

2016-12-01

When blurred images have saturated or over-exposed pixels, conventional blind deconvolution approaches often fail to estimate accurate point spread function (PSF) and will introduce local ringing artifacts. In this paper, we propose a method to deal with the problem under the modified multi-frame blind deconvolution framework. First, in the kernel estimation step, a light streak detection scheme using multi-frame blurred images is incorporated into the regularization constraint. Second, we deal with image regions affected by the saturated pixels separately by modeling a weighted matrix during each multi-frame deconvolution iteration process. Both synthetic and real-world examples show that more accurate PSFs can be estimated and restored images have richer details and less negative effects compared to state of art methods.

Adjustable long duration high-intensity point light source

NASA Astrophysics Data System (ADS)

Krehl, P.; Hagelweide, J. B.

1981-06-01

A new long duration high-intensity point light source with adjustable light duration and a small light spot locally stable in time has been developed. The principle involved is a stationary high-temperature plasma flow inside a partly constrained capillary of a coaxial spark gap which is viewed end on through a terminating Plexiglas window. The point light spark gap is operated via a resistor by an artificial transmission line. Using two exchangeable inductance sets in the line, two ranges of photoduration 10-130 μs and 100-600 μs can be covered. For a light spot size of 1.5 mm diameter the corresponding peak light output amounts to 5×106 and 1.6×106 candelas, respectively. Within these ranges the duration is controlled by an ignitron crowbar to extinguish the plasma. The adjustable photoduration is very useful for the application of continuous writing rotating mirror cameras, thus preventing multiple exposures. The essentially uniform exposure within the visible spectral range makes the new light source suitable for color cinematography.

Young Children Can Extend Motion Verbs to Point-Light Displays.

ERIC Educational Resources Information Center

Golinkoff, Roberta Michnick; Chung, He Len; Hirsh-Pasek, Kathy; Liu, Jing; Bertenthal, Bennett I.; Brand, Rebecca; Maguire, Mandy J.; Hennon, Elizabeth

2002-01-01

Used point-light displays (lights corresponding to the joints of the human body) to examine 3-year-olds' understanding of verbs. Found that children could extend familiar motion verbs (walking, dancing) to videotaped point-light actions shown in an intermodal preferential looking paradigm. Children watched the action matching the requested verb…

Does the estimation of light attenuation in tissue increase the accuracy of reflectance pulse oximetry at low oxygen saturations in vivo?

PubMed

Kisch-Wedel, H; Bernreuter, P; Kemming, G; Albert, M; Zwissler, B

2009-09-01

A new technique was validated in vivo in reflectance pulse oximetry for measuring low oxygen saturations. Two pairs of light emitter/detector diodes allow for estimation of light attenuation (LA) in tissue, which is assumed to be responsible for the inaccuracy of pulse oximetry at less than 70 % arterial oxygen saturation. For validation, 17 newborn piglets were desaturated stepwise from 21 % to 1.25 % inspiratory oxygen concentration during general anesthesia, and arterial oxygen saturation was measured with the reflectance pulse oximeter adjusted for LA in tissue, with a standard transmission pulse oximeter and a hemoximeter. LA in tissue could be quantified and was different between snout and foreleg (probability level (p) < 0.05). At arterial oxygen saturations above 70 %, the bias between the methods was at 0 %-1 % and the variability 4 %-5 %. From 2 % to 100 % arterial oxygen saturation, the reflectance pulse oximeter estimated oxyhemoglobin saturation more accurately than a conventional transmission pulse oximeter (p < 0.05). At low oxygen saturations below 70 %, the bias and variability of the reflectance pulse oximeter calibration were closer to the hemoximeter measurements than the transmission pulse oximeter (p < 0.05). The variability of the reflectance pulse oximeter was slightly lower than the traditional oximeter by taking into account the LA in tissue (9 % versus 11 % -15 %, ns), and thus, the quality of the individual calibration lines improved (correlation coefficient, p < 0.05).

Effects of aging on identifying emotions conveyed by point-light walkers.

PubMed

Spencer, Justine M Y; Sekuler, Allison B; Bennett, Patrick J; Giese, Martin A; Pilz, Karin S

2016-02-01

The visual system is able to recognize human motion simply from point lights attached to the major joints of an actor. Moreover, it has been shown that younger adults are able to recognize emotions from such dynamic point-light displays. Previous research has suggested that the ability to perceive emotional stimuli changes with age. For example, it has been shown that older adults are impaired in recognizing emotional expressions from static faces. In addition, it has been shown that older adults have difficulties perceiving visual motion, which might be helpful to recognize emotions from point-light displays. In the current study, 4 experiments were completed in which older and younger adults were asked to identify 3 emotions (happy, sad, and angry) displayed by 4 types of point-light walkers: upright and inverted normal walkers, which contained both local motion and global form information; upright scrambled walkers, which contained only local motion information; and upright random-position walkers, which contained only global form information. Overall, emotion discrimination accuracy was lower in older participants compared with younger participants, specifically when identifying sad and angry point-light walkers. In addition, observers in both age groups were able to recognize emotions from all types of point-light walkers, suggesting that both older and younger adults are able to recognize emotions from point-light walkers on the basis of local motion or global form. (c) 2016 APA, all rights reserved).

Dataset reporting the perceiver identification rates of basic emotions expressed by male, female and ambiguous gendered walkers in full-light, point-light and synthetically modelled point-light walkers.

PubMed

Halovic, Shaun; Kroos, Christian

2017-12-01

This data set describes the experimental data collected and reported in the research article "Walking my way? Walker gender and display format confounds the perception of specific emotions" (Halovic and Kroos, in press) [1]. The data set represent perceiver identification rates for different emotions (happiness, sadness, anger, fear and neutral), as displayed by full-light, point-light and synthetic point-light walkers. The perceiver identification scores have been transformed into H t rates, which represent proportions/percentages of correct identifications above what would be expected by chance. This data set also provides H t rates separately for male, female and ambiguously gendered walkers.

Correlation between capillary oxygen saturation and small intestinal wall thickness in the equine colic patient

PubMed Central

Mirle, Elisabeth; Wogatzki, Anna; Kunzmann, Robert; Schoenfelder, Axel M; Litzke, Lutz F

2017-01-01

The surgical evaluation of haemorrhagic infarcted intestine and the decision for or against bowel resection require a lot of experience and are subjective. The aim of this prospective, clinical study was to examine the correlation between oxygen saturation and small intestinal wall (IW) thickness, using two objective methods. In 22 colicky horses, the blood flow, oxygen saturation and relative amount of haemoglobin were measured intraoperatively via laser Doppler and white light spectroscopy (O2C, oxygen to see, LEA Medizintechnik) at six measuring points (MPs) in small and large intestines. Furthermore, the IW thickness was measured ultrasonographically. Nine of 22 horses had an increased small IW thickness greater than 4 mm (Freeman 2002, Scharner and others 2002, le Jeune and Whitcomb 2014) at measuring point 1 (MP1) (strangulated segment), four horses had a thickened bowel wall at measuring point 3 (MP3) (poststenotic) and one at measuring point 2 (MP2). The oxygen saturation was 0 at MP1 in six horses, at MP3 in two horses and at MP2 (prestenotic) in one. Oxygen saturation and small IW thickness were independent of each other at MP1 and MP2. At MP3, the two parameters were negatively correlated. In summary, it is not possible to draw conclusions about oxygen saturation based on IW thickness. PMID:28761667

Correlation between capillary oxygen saturation and small intestinal wall thickness in the equine colic patient.

PubMed

Mirle, Elisabeth; Wogatzki, Anna; Kunzmann, Robert; Schoenfelder, Axel M; Litzke, Lutz F

2017-01-01

The surgical evaluation of haemorrhagic infarcted intestine and the decision for or against bowel resection require a lot of experience and are subjective. The aim of this prospective, clinical study was to examine the correlation between oxygen saturation and small intestinal wall (IW) thickness, using two objective methods. In 22 colicky horses, the blood flow, oxygen saturation and relative amount of haemoglobin were measured intraoperatively via laser Doppler and white light spectroscopy (O2C, oxygen to see, LEA Medizintechnik) at six measuring points (MPs) in small and large intestines. Furthermore, the IW thickness was measured ultrasonographically. Nine of 22 horses had an increased small IW thickness greater than 4 mm (Freeman 2002, Scharner and others 2002, le Jeune and Whitcomb 2014) at measuring point 1 (MP1) (strangulated segment), four horses had a thickened bowel wall at measuring point 3 (MP3) (poststenotic) and one at measuring point 2 (MP2). The oxygen saturation was 0 at MP1 in six horses, at MP3 in two horses and at MP2 (prestenotic) in one. Oxygen saturation and small IW thickness were independent of each other at MP1 and MP2. At MP3, the two parameters were negatively correlated. In summary, it is not possible to draw conclusions about oxygen saturation based on IW thickness.

From global to heavy-light: 5-point conformal blocks

NASA Astrophysics Data System (ADS)

Alkalaev, Konstantin; Belavin, Vladimir

2016-03-01

We consider Virasoro conformal blocks in the large central charge limit. There are different regimes depending on the behavior of the conformal dimensions. The most simple regime is reduced to the global sl(2,C) conformal blocks while the most complicated one is known as the classical conformal blocks. Recently, Fitzpatrick, Kaplan, and Walters showed that the two regimes are related through the intermediate stage of the so-called heavy-light semiclassical limit. We study this idea in the particular case of the 5-point conformal block. To find the 5-point global block we use the projector technique and the Casimir operator approach. Furthermore, we discuss the relation between the global and the heavy-light limits and construct the heavy-light block from the global block. In this way we reproduce our previous results for the 5-point perturbative classical block obtained by means of the monodromy method.

CORE SATURATION BLOCKING OSCILLATOR

DOEpatents

Spinrad, R.J.

1961-10-17

A blocking oscillator which relies on core saturation regulation to control the output pulse width is described. In this arrangement an external magnetic loop is provided in which a saturable portion forms the core of a feedback transformer used with the thermionic or semi-conductor active element. A first stationary magnetic loop establishes a level of flux through the saturation portion of the loop. A second adjustable magnet moves the flux level to select a saturation point giving the desired output pulse width. (AEC)

Gender Recognition from Point-Light Walkers

ERIC Educational Resources Information Center

Pollick, Frank E.; Kay, Jim W.; Heim, Katrin; Stringer, Rebecca

2005-01-01

Point-light displays of human gait provide information sufficient to recognize the gender of a walker and are taken as evidence of the exquisite tuning of the visual system to biological motion. The authors revisit this topic with the goals of quantifying human efficiency at gender recognition. To achieve this, the authors first derive an ideal…

Hue-saturation-density (HSD) model for stain recognition in digital images from transmitted light microscopy.

PubMed

van Der Laak, J A; Pahlplatz, M M; Hanselaar, A G; de Wilde, P C

2000-04-01

Transmitted light microscopy is used in pathology to examine stained tissues. Digital image analysis is gaining importance as a means to quantify alterations in tissues. A prerequisite for accurate and reproducible quantification is the possibility to recognise stains in a standardised manner, independently of variations in the staining density. The usefulness of three colour models was studied using data from computer simulations and experimental data from an immuno-doublestained tissue section. Direct use of the three intensities obtained by a colour camera results in the red-green-blue (RGB) model. By decoupling the intensity from the RGB data, the hue-saturation-intensity (HSI) model is obtained. However, the major part of the variation in perceived intensities in transmitted light microscopy is caused by variations in staining density. Therefore, the hue-saturation-density (HSD) transform was defined as the RGB to HSI transform, applied to optical density values rather than intensities for the individual RGB channels. In the RGB model, the mixture of chromatic and intensity information hampers standardisation of stain recognition. In the HSI model, mixtures of stains that could be distinguished from other stains in the RGB model could not be separated. The HSD model enabled all possible distinctions in a two-dimensional, standardised data space. In the RGB model, standardised recognition is only possible by using complex and time-consuming algorithms. The HSI model is not suitable for stain recognition in transmitted light microscopy. The newly derived HSD model was found superior to the existing models for this purpose. Copyright 2000 Wiley-Liss, Inc.

Mechanism of gas saturated oil viscosity anomaly near to phase transition point

NASA Astrophysics Data System (ADS)

Suleimanov, Baghir A.; Abbasov, Elkhan M.; Sisenbayeva, Marziya R.

2017-01-01

The article presents experimental studies of the phase behavior by the flash liberation test and of the viscosity of the live oil at different pressures. Unlike the typical studies at the pressure near the saturation pressure, the measurements were conducted at a relatively small pressure increment of 0.08-0.25 MPa. The viscosity anomaly was discovered experimentally near to the phase transition point in the range of the pressure levels P/Pb = 1-1.14 (Pb—bubble point pressure) and shows that it decreases about 70 times in comparison to the viscosity at the reservoir pressure. It was found that the bubble point pressure decreases significantly (up to 36%) with surfactant addition. Furthermore, the viscosity of the live oil at the surfactant concentration of 5 wt. % decreases almost 37 times in comparison to the viscosity at the reservoir pressure. The mechanism of observed effects was suggested based on the formation of the stable subcritical gas nuclei and associated slippage effect. The mechanism for the stabilization of the subcritical nuclei by the combined action of the surface and electrical forces, as well as the morphology of the formed nanobubbles, was considered. The model for determining the oil viscosity taking into account the slippage effect was suggested.

Stable high-power saturable absorber based on polymer-black-phosphorus films

NASA Astrophysics Data System (ADS)

Mao, Dong; Li, Mingkun; Cui, Xiaoqi; Zhang, Wending; Lu, Hua; Song, Kun; Zhao, Jianlin

2018-01-01

Black phosphorus (BP), a rising two-dimensional material with a layer-number-dependent direct bandgap of 0.3-1.5 eV, is very interesting for optoelectronics applications from near- to mid-infrared wavebands. In the atmosphere, few-layer BP tends to be oxidized or degenerated during interacting with lasers. Here, we fabricate few-layer BP nanosheets based on a liquid exfoliation method using N-methylpyrrolidone as the dispersion liquid. By incorporating BP nanosheets with polymers (polyvinyl alcohol or high-melting-point polyimide), two flexible filmy BP saturable absorbers are fabricated to realize passive mode locking in erbium-doped fiber lasers. The polymer-BP saturable absorber, especially the polyimide-BP saturable absorber, can prevent the oxidation or water-induced etching under high-power laser illuminations, providing a promising candidate for Q-switchers, mode lockers, and light modulators.

Effect of dynamic oxygen concentrations on the growth of Neochloris oleoabundans at sub-saturating light conditions.

PubMed

Sousa, Claudia; Valev, Dimitar; Vermuë, Marian H; Wijffels, Rene H

2013-08-01

In tubular photobioreactors micro-algae continuously experience dynamically changing oxygen and light conditions when circulating from the solar receiver to the dark degasser. These changes in oxygen concentration and light were simulated in a CSTR using sub-saturating light intensity. Elongation of the residence time in the solar receiver from 30 to 300 min was also investigated. Specific growth rates measured at constant low oxygen concentration PO2=0.21 bar were; 1.14 ± 0.06 day(-1) using continuous light 0.80 ± 0.16 day(-1) with 30 min light and 1.09 ± 0.05 day(-1) with 300 min light. The effect of dynamically changing oxygen concentrations from PO2=0.21 to 0.63 bar followed by degassing resulted in similar specific growth rates. The exposure of the algae cells to dark periods in the degasser has a bigger negative impact than the temporary exposure to accumulating oxygen concentrations in the solar receiver. This shows that considerable energy savings for degassing are possible. Copyright © 2013 Elsevier Ltd. All rights reserved.

Growth of the microalgae Neochloris oleoabundans at high partial oxygen pressures and sub-saturating light intensity.

PubMed

Sousa, Cláudia; de Winter, Lenneke; Janssen, Marcel; Vermuë, Marian H; Wijffels, René H

2012-01-01

The effect of partial oxygen pressure on growth of Neochloris oleoabundans was studied at sub-saturating light intensity in a fully-controlled stirred tank photobioreactor. At the three partial oxygen pressures tested (P(O)₂= 0.24; 0.63; 0.84 bar), the specific growth rate was 1.38; 1.36 and 1.06 day(-1), respectively. An increase of the P(CO)₂from 0.007 to 0.02 bar at P(O₂) of 0.84 bar resulted in an increase in the growth rate from 1.06 to 1.36 day(-1). These results confirm that the reduction of algal growth at high oxygen concentrations at sub-saturating light conditions is mainly caused by competitive inhibition of Rubisco. This negative effect on growth can be overcome by restoring the O(2)/CO(2) ratio by an increase in the partial carbon dioxide pressure. In comparison to general practice (P(O(2)) = 0.42 bar), working at partial O(2) pressure of 0.84 bar could reduce the energy requirement for degassing by a factor of 3-4. Copyright © 2011 Elsevier Ltd. All rights reserved.

Unidirectional reflectionless light propagation at exceptional points

NASA Astrophysics Data System (ADS)

Huang, Yin; Shen, Yuecheng; Min, Changjun; Fan, Shanhui; Veronis, Georgios

2017-05-01

In this paper, we provide a comprehensive review of unidirectional reflectionless light propagation in photonic devices at exceptional points (EPs). EPs, which are branch point singularities of the spectrum, associated with the coalescence of both eigenvalues and corresponding eigenstates, lead to interesting phenomena, such as level repulsion and crossing, bifurcation, chaos, and phase transitions in open quantum systems described by non-Hermitian Hamiltonians. Recently, it was shown that judiciously designed photonic synthetic matters could mimic the complex non-Hermitian Hamiltonians in quantum mechanics and realize unidirectional reflection at optical EPs. Unidirectional reflectionlessness is of great interest for optical invisibility. Achieving unidirectional reflectionless light propagation could also be potentially important for developing optical devices, such as optical network analyzers. Here, we discuss unidirectional reflectionlessness at EPs in both parity-time (PT)-symmetric and non-PT-symmetric optical systems. We also provide an outlook on possible future directions in this field.

Image-guided optical measurement of blood oxygen saturation within capillary vessels (Conference Presentation)

NASA Astrophysics Data System (ADS)

Akons, Kfir; Zeidan, Adel; Yeheskely-Hayon, Daniella; Minai, Limor; Yelin, Dvir

2016-03-01

Values of blood oxygenation levels are useful for assessing heart and lung conditions, and are frequently monitored during routine patient care. Independent measurement of the oxygen saturation in capillary blood, which is significantly different from that of arterial blood, is important for diagnosing tissue hypoxia and for increasing the accuracy of existing techniques that measure arterial oxygen saturation. Here, we developed a simple, non-invasive technique for measuring the reflected spectra from individual capillary vessels within a human lip, allowing local measurement of the blood oxygen saturation. The optical setup includes a spatially incoherent broadband light that was focused onto a specific vessel below the lip surface. Backscattered light was imaged by a camera for identifying a target vessel and pointing the illumination beam to its cross section. Scattered light from the vessel was then collected by a single-mode fiber and analyzed by a fast spectrometer. Spectra acquired from small capillary vessels within a volunteer lip showed the characteristic oxyhemoglobin absorption bands in real time and with a high signal-to-noise ratio. Measuring capillary oxygen saturation using this technique would potentially be more accurate compared to existing pulse oximetry techniques due to its insensitivity to the patient's skin color, pulse rate, motion, and medical condition. It could be used as a standalone endoscopic technique for measuring tissue hypoxia or in conjunction with conventional pulse oximetry for a more accurate measurement of oxygen transport in the body.

Graphene-clad microfibre saturable absorber for ultrafast fibre lasers.

PubMed

Liu, X M; Yang, H R; Cui, Y D; Chen, G W; Yang, Y; Wu, X Q; Yao, X K; Han, D D; Han, X X; Zeng, C; Guo, J; Li, W L; Cheng, G; Tong, L M

2016-05-16

Graphene, whose absorbance is approximately independent of wavelength, allows broadband light-matter interactions with ultrafast responses. The interband optical absorption of graphene can be saturated readily under strong excitation, thereby enabling scientists to exploit the photonic properties of graphene to realize ultrafast lasers. The evanescent field interaction scheme of the propagating light with graphene covered on a D-shaped fibre or microfibre has been employed extensively because of the nonblocking configuration. Obviously, most of the fibre surface is unused in these techniques. Here, we exploit a graphene-clad microfibre (GCM) saturable absorber in a mode-locked fibre laser for the generation of ultrafast pulses. The proposed all-surface technique can guarantee a higher efficiency of light-graphene interactions than the aforementioned techniques. Our GCM-based saturable absorber can generate ultrafast optical pulses within 1.5 μm. This saturable absorber is compatible with current fibre lasers and has many merits such as low saturation intensities, ultrafast recovery times, and wide wavelength ranges. The proposed saturable absorber will pave the way for graphene-based wideband photonics.

An efficient method to compute microlensed light curves for point sources

NASA Technical Reports Server (NTRS)

Witt, Hans J.

1993-01-01

We present a method to compute microlensed light curves for point sources. This method has the general advantage that all microimages contributing to the light curve are found. While a source moves along a straight line, all micro images are located either on the primary image track or on the secondary image tracks (loops). The primary image track extends from - infinity to + infinity and is made of many sequents which are continuously connected. All the secondary image tracks (loops) begin and end on the lensing point masses. The method can be applied to any microlensing situation with point masses in the deflector plane, even for the overcritical case and surface densities close to the critical. Furthermore, we present general rules to evaluate the light curve for a straight track arbitrary placed in the caustic network of a sample of many point masses.

Maskless direct laser writing with visible light: Breaking through the optical resolving limit with cooperative manipulations of nonlinear reverse saturation absorption and thermal diffusion

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

Wei, Jingsong, E-mail: weijingsong@siom.ac.cn; Wang, Rui; University of Chinese Academy of Sciences, Beijing 100049

In this work, the resolving limit of maskless direct laser writing is overcome by cooperative manipulation from nonlinear reverse saturation absorption and thermal diffusion, where the nonlinear reverse saturation absorption can induce the formation of below diffraction-limited energy absorption spot, and the thermal diffusion manipulation can make the heat quantity at the central region of energy absorption spot propagate along the thin film thickness direction. The temperature at the central region of energy absorption spot transiently reaches up to melting point and realizes nanolithography. The sample “glass substrate/AgInSbTe” is prepared, where AgInSbTe is taken as nonlinear reverse saturation absorption thinmore » film. The below diffraction-limited energy absorption spot is simulated theoretically and verified experimentally by near-field spot scanning method. The “glass substrate/Al/AgInSbTe” sample is prepared, where the Al is used as thermal conductive layer to manipulate the thermal diffusion channel because the thermal diffusivity coefficient of Al is much larger than that of AgInSbTe. The direct laser writing is conducted by a setup with a laser wavelength of 650 nm and a converging lens of NA=0.85, the lithographic marks with a size of about 100 nm are obtained, and the size is only about 1/10 the incident focused spot. The experimental results indicate that the cooperative manipulation from nonlinear reverse saturation absorption and thermal diffusion is a good method to realize nanolithography in maskless direct laser writing with visible light.« less

Brine saturation technique for extraction of light filth from rubbed, ground, and whole sage: collaborative study.

PubMed

Freeman, C C

1985-01-01

A new approach to the isolation of light filth from the 3 commercial forms of sage was studied collaboratively. It incorporates a simple isopropanol defatting, followed by saturation of the product with brine by alternately heating and cooling, and subsequent trapping of filth from tap water with olive oil. This method circumvents the use of hazardous, expensive solvents and more time-consuming pretreatment procedures. Overall recoveries were 92.1% for rodent hair and 78.7% for insect fragments on clean, easy-to-read papers. An additional blending step was necessary to obtain satisfactory recovery of rodent hair fragments from whole sage. The method has been adopted official first action for light filth in rubbed and ground sage only.

Teaching Light Compensation Point: A New Practical Approach.

ERIC Educational Resources Information Center

Aston, T. J.; Robinson, G.

1986-01-01

Describes a simple method for measuring respiration, net photosynthesis, and compensation points of plants in relation to light intensity. Outlines how the method can be used in teaching physiological adaptation. Includes a set of the experiment's results. (ML)

Grid point extraction and coding for structured light system

NASA Astrophysics Data System (ADS)

Song, Zhan; Chung, Ronald

2011-09-01

A structured light system simplifies three-dimensional reconstruction by illuminating a specially designed pattern to the target object, thereby generating a distinct texture on it for imaging and further processing. Success of the system hinges upon what features are to be coded in the projected pattern, extracted in the captured image, and matched between the projector's display panel and the camera's image plane. The codes have to be such that they are largely preserved in the image data upon illumination from the projector, reflection from the target object, and projective distortion in the imaging process. The features also need to be reliably extracted in the image domain. In this article, a two-dimensional pseudorandom pattern consisting of rhombic color elements is proposed, and the grid points between the pattern elements are chosen as the feature points. We describe how a type classification of the grid points plus the pseudorandomness of the projected pattern can equip each grid point with a unique label that is preserved in the captured image. We also present a grid point detector that extracts the grid points without the need of segmenting the pattern elements, and that localizes the grid points in subpixel accuracy. Extensive experiments are presented to illustrate that, with the proposed pattern feature definition and feature detector, more features points in higher accuracy can be reconstructed in comparison with the existing pseudorandomly encoded structured light systems.

Lighting system with thermal management system having point contact synthetic jets

DOEpatents

Arik, Mehmet; Weaver, Stanton Earl; Kuenzler, Glenn Howard; Wolfe, Jr., Charles Franklin; Sharma, Rajdeep

2013-12-10

Lighting system having unique configurations are provided. For instance, the lighting system may include a light source, a thermal management system and driver electronics, each contained within a housing structure. The light source is configured to provide illumination visible through an opening in the housing structure. The thermal management system includes a plurality of synthetic jets. The synthetic jets are arranged within the lighting system such that they are secured at contact points.

Lighting system with thermal management system having point contact synthetic jets

DOEpatents

Arik, Mehmet; Weaver, Stanton Earl; Kuenzler, Glenn Howard; Wolfe, Jr, Charles Franklin; Sharma, Rajdeep

2016-08-30

Lighting systems having unique configurations are provided. For instance, the lighting system may include a light source, a thermal management system and driver electronics, each contained within a housing structure. The light source is configured to provide illumination visible through an opening in the housing structure. The thermal management system includes a plurality of synthetic jets. The synthetic jets are arranged within the lighting system such that they are secured at contact points.

Lighting system with thermal management system having point contact synthetic jets

DOEpatents

Arik, Mehmet; Weaver, Stanton Earl; Kuenzler, Glenn Howard; Wolfe, Jr., Charles Franklin; Sharma, Rajdeep

2016-08-23

Lighting systems having unique configurations are provided. For instance, the lighting system may include a light source, a thermal management system and driver electronics, each contained within a housing structure. The light source is configured to provide illumination visible through an opening in the housing structure. The thermal management system includes a plurality of synthetic jets. The synthetic jets are arranged within the lighting system such that they are secured at contact points.

[Response of photosynthetic characteristics of peanut seedlings leaves to low light].

PubMed

Zhang, Kun; Wan, Yong-shan; Liu, Feng-zhen; Zhang, Er-qun; Wang, Su

2009-12-01

To investigate the effects of shading and light recovery on the photosynthetic characteristics of peanut seedlings leaves, different shading treatments including no shading, 27% shading, 43% shading, and 77% shading were performed with black sunshade net at the seedling stage of two peanut cultivars Fenghua 1 and Fenghua 2, with related parameters determined. It was shown that with the increase of shading degree, the leaf chlorophyll content, actual PSII photochemical efficiency under irradiance (phi(PS II)), and maximum PS II photochemical efficiency (Fv/Fm) of test cultivars increased, while the Chl a/b ratio and photosynthetic rate (Pn) decreased. On the first day after light recovery, the Pn and stomatal conductance (Gs) decreased while the intercellular CO2 concentration (Ci) increased with increasing shading degree when measured under high light, but the Pn increased and the Gs and Ci decreased with increasing shading degree when measured under low light. The ratio of Pn measured under low light to that measured under high light increased significantly. With increasing shading degree, the light compensation point, light saturation point, CO2 compensation point, CO2 saturation point, and carboxylation efficiency decreased, while the apparent quantum yield increased. After the removal of shading, the Pn, phi(PS II), and Fv/Fm under natural light decreased immediately, but increased gradually 3-5 days after. 15 days after light recovery, the Pn, phi(PS II) and Fv/Fm in treatment 27% shading recovered to the level of no shading. As for the other treatments, the restored extent differed with shading degree and test variety. In the same treatments, the leaf chlorophyll content, Pn and phi(PS II) of Fenghua 1 were higher than those of Fenghua 2. The results demonstrated that shading at seedling stage improved the capabilities of test varieties in using low light, but reduced the capabilities in using high light.

Modeling Oceanic Primary Production: Photoacclimation and Nutrient Effects on Light-saturated Photosynthesis

NASA Technical Reports Server (NTRS)

Behrenfeld, Michael J.; Maranon, Emilio; Siegel, David A.; Hooker, Stanford B.

2000-01-01

In this report, we describe a new model (the 'PhotoAcc' model) for estimating changes in the light-saturated rate of chlorophyll-normalized phytoplankton carbon fixation (Pbmax). The model is based on measurements conducted during the Atlantic Meridional Transect studies and the Bermuda Time Series program. The PhotoAcc model explained 64% to 82% of the observed variability in Pbmax for our data set, whereas none of the previously published Pbmax models described over the past 44 years explained any of the variance. The significance of this result is that a primary limiting factor for extracting ocean carbon fixation rates from satellite measurements of near surface chlorophyll has been errors in the estimate of Pbmax. Our new model should thus result in much improved calculations of oceanic photosynthesis and thus the role of the oceans in the global carbon cycle.

Controls of the quantum yield and saturation light of isoprene emission in different-aged aspen leaves

PubMed Central

Niinemets, Ülo; Sun, Zhihong; Talts, Eero

2018-01-01

Leaf age alters the balance between the use of end-product of plastidic isoprenoid synthesis pathway, dimethylallyl diphosphate (DMADP), in prenyltransferase reactions leading to synthesis of pigments of photosynthetic machinery and in isoprene synthesis, but the implications of such changes on environmental responses of isoprene emission have not been studied. Because under light-limited conditions, isoprene emission rate is controlled by DMADP pool size (SDMADP), shifts in the share of different processes are expected to particularly strongly alter the light dependency of isoprene emission. We examined light responses of isoprene emission in young fully-expanded, mature and old non-senescent leaves of hybrid aspen (Populus tremula x P. tremuloides) and estimated in vivo SDMADP and isoprene synthase activity from postillumination isoprene release. Isoprene emission capacity was 1.5-fold larger in mature than in young and old leaves. The initial quantum yield of isoprene emission (αI) increased by 2.5-fold with increasing leaf age primarily as the result of increasing SDMADP. The saturating light intensity (QI90) decreased by 2.3-fold with increasing leaf age, and this mainly reflected limited light-dependent increase of SDMADP possibly due to feedback inhibition by DMADP. These major age-dependent changes in the shape of the light response need consideration in modeling canopy isoprene emission. PMID:26037962

Controls of the quantum yield and saturation light of isoprene emission in different-aged aspen leaves.

PubMed

Niinemets, Ülo; Sun, Zhihong; Talts, Eero

2015-12-01

Leaf age alters the balance between the use of end-product of plastidic isoprenoid synthesis pathway, dimethylallyl diphosphate (DMADP), in prenyltransferase reactions leading to synthesis of pigments of photosynthetic machinery and in isoprene synthesis, but the implications of such changes on environmental responses of isoprene emission have not been studied. Because under light-limited conditions, isoprene emission rate is controlled by DMADP pool size (SDMADP ), shifts in the share of different processes are expected to particularly strongly alter the light dependency of isoprene emission. We examined light responses of isoprene emission in young fully expanded, mature and old non-senescent leaves of hybrid aspen (Populus tremula x P. tremuloides) and estimated in vivo SDMADP and isoprene synthase activity from post-illumination isoprene release. Isoprene emission capacity was 1.5-fold larger in mature than in young and old leaves. The initial quantum yield of isoprene emission (αI ) increased by 2.5-fold with increasing leaf age primarily as the result of increasing SDMADP . The saturating light intensity (QI90 ) decreased by 2.3-fold with increasing leaf age, and this mainly reflected limited light-dependent increase of SDMADP possibly due to feedback inhibition by DMADP. These major age-dependent changes in the shape of the light response need consideration in modelling canopy isoprene emission. © 2015 John Wiley & Sons Ltd.

An Optical Index of Phytoplankton Photoacclimation and Its Relation to Light-Saturated Photosynthesis in the Sea

NASA Technical Reports Server (NTRS)

Behrenfeld, Michael J.; Boss, Emmanuel; Lyon, Paul E.; Fennel, Katja; Hoge, Frank E.; Koblinsky, Chester J. (Technical Monitor)

2002-01-01

In relation to understanding ocean biology at the global scale, one of NASA's primary foci has been measurements of near-surface concentrations of phytoplankton chlorophyll. Chlorophyll is an important light-absorbing pigment in phytoplankton. The absorbed light energy is used to fix carbon in the process of photosynthesis. Photosynthesis, in turn, is critical to the growth of phytoplankton and the function of entire marine ecosystems. Thus, the use of satellite surface chlorophyll data to estimate primary production in the ocean has been a key focus of much biological oceanography research. One of the major challenges in this research is to develop relationships that allow a given chlorophyll concentration (a standing stock) to be interpreted in terms of carbon fixation (a rate). This problem centers on the description of the light-saturated photosynthetic rate, Pbmax. In this paper, we describe how optical measurements of light attenuation provide information on particulate organic carbon (POC) concentrations. We then show how the ratio of POC to chlorophyll (Theta) provides critical information on variability in Pbmax. We then test this relationship between Theta and Pbmax using field data from a variety of open ocean ecosystems.

Mechanistic Models of Light-limited and Light-saturated Rates of Photosynthesis

DTIC Science & Technology

1997-09-30

concentrations of the rate-limiting enzyme ribulose-1,5-bisphosphate carboxylase ( Rubisco ) that catalyzes carbon fixation. This work is supported by...saturated photosynthesis as a function of the activity of the key photosynthetic enzyme ribulose-1,5-bisphosphate carboxylase ( Rubisco ) for a Report...concentration and its specific rate. The Rubisco activities were determined at the same temperature as the photosynthetic measurements, and hence did not

A solution thermodynamics definition of the fiber saturation point and the derivation of a wood-water phase (state) diagram

Treesearch

Samuel L. Zelinka; Samuel V. Glass; Joseph E. Jakes; Donald S. Stone

2016-01-01

The fiber saturation point (FSP) is an important concept in wood– moisture relations that differentiates between the states of water in wood and has been discussed in the literature for over 100 years. Despite its importance and extensive study, the exact theoretical definition of the FSP and the operational definition (the correct way to measure the FSP) are still...

Coding and decoding in a point-to-point communication using the polarization of the light beam.

PubMed

Kavehvash, Z; Massoumian, F

2008-05-10

A new technique for coding and decoding of optical signals through the use of polarization is described. In this technique the concept of coding is translated to polarization. In other words, coding is done in such a way that each code represents a unique polarization. This is done by implementing a binary pattern on a spatial light modulator in such a way that the reflected light has the required polarization. Decoding is done by the detection of the received beam's polarization. By linking the concept of coding to polarization we can use each of these concepts in measuring the other one, attaining some gains. In this paper the construction of a simple point-to-point communication where coding and decoding is done through polarization will be discussed.

Developmental changes in emotion recognition from full-light and point-light displays of body movement.

PubMed

Ross, Patrick D; Polson, Louise; Grosbras, Marie-Hélène

2012-01-01

To date, research on the development of emotion recognition has been dominated by studies on facial expression interpretation; very little is known about children's ability to recognize affective meaning from body movements. In the present study, we acquired simultaneous video and motion capture recordings of two actors portraying four basic emotions (Happiness Sadness, Fear and Anger). One hundred and seven primary and secondary school children (aged 4-17) and 14 adult volunteers participated in the study. Each participant viewed the full-light and point-light video clips and was asked to make a forced-choice as to which emotion was being portrayed. As a group, children performed worse than adults for both point-light and full-light conditions. Linear regression showed that both age and lighting condition were significant predictors of performance in children. Using piecewise regression, we found that a bilinear model with a steep improvement in performance until 8.5 years of age, followed by a much slower improvement rate through late childhood and adolescence best explained the data. These findings confirm that, like for facial expression, adolescents' recognition of basic emotions from body language is not fully mature and seems to follow a non-linear development. This is in line with observations of non-linear developmental trajectories for different aspects of human stimuli processing (voices and faces), perhaps suggesting a shift from one perceptual or cognitive strategy to another during adolescence. These results have important implications to understanding the maturation of social cognition.

Ultra-fast switching of light by absorption saturation in vacuum ultra-violet region.

PubMed

Yoneda, Hitoki; Inubushi, Yuichi; Tanaka, Toshihiro; Yamaguchi, Yuta; Sato, Fumiya; Morimoto, Shunsuke; Kumagai, Taisuke; Nagasono, Mitsuru; Higashiya, Atsushi; Yabashi, Makina; Ishikawa, Tetsuya; Ohashi, Haruhiko; Kimura, Hiroaki; Kitamura, Hikaru; Kodama, Ryosuke

2009-12-21

Advances in free electron lasers producing high energy photons [Nat. Photonics 2(9), 555-559 (2008)] are expected to open up a new science of nonlinear optics of high energy photons. Specifically, lasers of photon energy higher than the plasma frequency of a metal can show new interaction features because they can penetrate deeply into metals without strong reflection. Here we show the observation of ultra-fast switching of vacuum ultra-violet (VUV) light caused by saturable absorption of a solid metal target. A strong gating is observed at energy fluences above 6J/cm2 at wavelength of 51 nm with tin metal thin layers. The ratio of the transmission at high intensity to low intensity is typically greater than 100:1. This means we can design new nonlinear photonic devices such as auto-correlator and pulse slicer for the VUV region.

Laser scanning saturated structured illumination microscopy based on phase modulation

NASA Astrophysics Data System (ADS)

Huang, Yujia; Zhu, Dazhao; Jin, Luhong; Kuang, Cuifang; Xu, Yingke; Liu, Xu

2017-08-01

Wide-field saturated structured illumination microscopy has not been widely used due to the requirement of high laser power. We propose a novel method called laser scanning saturated structured illumination microscopy (LS-SSIM), which introduces high order of harmonics frequency and greatly reduces the required laser power for SSIM imaging. To accomplish that, an excitation PSF with two peaks is generated and scanned along different directions on the sample. Raw images are recorded cumulatively by a CCD detector and then reconstructed to form a high-resolution image with extended optical transfer function (OTF). Our theoretical analysis and simulation results show that LS-SSIM method reaches a resolution of 0.16 λ, equivalent to 2.7-fold resolution than conventional wide-field microscopy. In addition, LS-SSIM greatly improves the optical sectioning capability of conventional wide-field illumination system by diminishing our-of-focus light. Furthermore, this modality has the advantage of implementation in multi-photon microscopy with point scanning excitation to image samples in greater depths.

Point to point multispectral light projection applied to cultural heritage

NASA Astrophysics Data System (ADS)

Vázquez, D.; Alvarez, A.; Canabal, H.; Garcia, A.; Mayorga, S.; Muro, C.; Galan, T.

2017-09-01

Use of new of light sources based on LED technology should allow the develop of systems that combine conservation and exhibition requirements and allow to make these art goods available to the next generations according to sustainability principles. The goal of this work is to develop light systems and sources with an optimized spectral distribution for each specific point of the art piece. This optimization process implies to maximize the color fidelity reproduction and the same time to minimize the photochemical damage. Perceived color under these sources will be similar (metameric) to technical requirements given by the restoration team uncharged of the conservation and exhibition of the goods of art. Depending of the fragility of the exposed art objects (i.e. spectral responsivity of the material) the irradiance must be kept under a critical level. Therefore, it is necessary to develop a mathematical model that simulates with enough accuracy both the visual effect of the illumination and the photochemical impact of the radiation. Spectral reflectance of a reference painting The mathematical model is based on a merit function that optimized the individual intensity of the LED-light sources taking into account the damage function of the material and color space coordinates. Moreover the algorithm used weights for damage and color fidelity in order to adapt the model to a specific museal application. In this work we show a sample of this technology applied to a picture of Sorolla (1863-1923) an important Spanish painter title "woman walking at the beach".

A point particle model of lightly bound skyrmions

NASA Astrophysics Data System (ADS)

Gillard, Mike; Harland, Derek; Kirk, Elliot; Maybee, Ben; Speight, Martin

2017-04-01

A simple model of the dynamics of lightly bound skyrmions is developed in which skyrmions are replaced by point particles, each carrying an internal orientation. The model accounts well for the static energy minimizers of baryon number 1 ≤ B ≤ 8 obtained by numerical simulation of the full field theory. For 9 ≤ B ≤ 23, a large number of static solutions of the point particle model are found, all closely resembling size B subsets of a face centred cubic lattice, with the particle orientations dictated by a simple colouring rule. Rigid body quantization of these solutions is performed, and the spin and isospin of the corresponding ground states extracted. As part of the quantization scheme, an algorithm to compute the symmetry group of an oriented point cloud, and to determine its corresponding Finkelstein-Rubinstein constraints, is devised.

Bistability By Self-Reflection In A Saturable Absorber

NASA Astrophysics Data System (ADS)

Roso-Franco, Luis

1987-01-01

Propagation of laser light through a saturable absorber is theoretically studied. Computed steady state solutions of the Maxwell equations describing the unidimensional propagation of a plane monochromatic wave without introducing the slowly-varying envelope approximation are presented showing how saturation effects can influence the absorption of the field. At a certain range of refractive index and extintion coefficients, computed solutions display a very susprising behaviour, and a self-reflected wave appears inside the absorber. This can be useful for a new kind of biestable device, similar to a standard bistable cavity but with the back mirror self-induced by the light.

Hole-ness of point clouds

NASA Astrophysics Data System (ADS)

Gronz, Oliver; Seeger, Manuel; Klaes, Björn; Casper, Markus C.; Ries, Johannes B.

2015-04-01

Accurate and dense 3D models of soil surfaces can be used in various ways: They can be used as initial shapes for erosion models. They can be used as benchmark shapes for erosion model outputs. They can be used to derive metrics, such as random roughness... One easy and low-cost method to produce these models is structure from motion (SfM). Using this method, two questions arise: Does the soil moisture, which changes the colour, albedo and reflectivity of the soil, influence the model quality? How can the model quality be evaluated? To answer these questions, a suitable data set has been produced: soil has been placed on a tray and areas with different roughness structures have been formed. For different moisture states - dry, medium, saturated - and two different lighting conditions - direct and indirect - sets of high-resolution images at the same camera positions have been taken. From the six image sets, 3D point clouds have been produced using VisualSfM. The visual inspection of the 3D models showed that all models have different areas, where holes of different sizes occur. But it is obviously a subjective task to determine the model's quality by visual inspection. One typical approach to evaluate model quality objectively is to estimate the point density on a regular, two-dimensional grid: the number of 3D points in each grid cell projected on a plane is calculated. This works well for surfaces that do not show vertical structures. Along vertical structures, many points will be projected on the same grid cell and thus the point density rather depends on the shape of the surface but less on the quality of the model. Another approach has been applied by using the points resulting from Poisson Surface Reconstructions. One of this algorithm's properties is the filling of holes: new points are interpolated inside the holes. Using the original 3D point cloud and the interpolated Poisson point set, two analyses have been performed: For all Poisson points, the

New porcine test-model reveals remarkable differences between algorithms for spectrophotometrical haemoglobin saturation measurements with VLS.

PubMed

Gade, John; Greisen, Gorm

2016-09-01

The study created an 'ex vivo' model to test different algorithms for measurements of mucosal haemoglobin saturation with visible light spectrophotometry (VLS). The model allowed comparison between algorithms, but it also allowed comparison with co-oximetry using a 'gold standard' method. This has not been described before. Seven pigs were used. They were perfused with cold Haemaxel, and thus killed, chilled and becoming bloodless. The bronchial artery was perfused with cold blood with known saturation and spectrophotometrical measurements were made through a bronchoscope. Based on 42 spectrophotometrical measurements of porcine bronchial mucosa saturation with fully oxygenated blood and 21 with de-oxygenated blood, six algorithms were applied to the raw-spectra of the measurements and compared with co-oxymetry. The difference from co-oxymetry in the oxygenated and de-oxygenated state ranged from  -32.8 to  +29.9 percentage points and from  -5.0 to  +9.2 percentage points, respectively. the algorithms showed remarkable in-between differences when tested on raw-spectra from an 'ex vivo' model. All algorithms had bias, more marked at high oxygenation than low oxygenation. Three algorithms were dis-recommended.

Non-invasive three-dimension control of light between turbid layers using a surface quasi-point light source for precorrection.

PubMed

Qiao, Mu; Liu, Honglin; Pang, Guanghui; Han, Shensheng

2017-08-29

Manipulating light non-invasively through inhomogeneous media is an attractive goal in many disciplines. Wavefront shaping and optical phase conjugation can focus light to a point. Transmission matrix method can control light on multiple output modes simultaneously. Here we report a non-invasive approach which enables three-dimension (3D) light control between two turbid layers. A digital optical phase conjugation mirror measured and conjugated the diffused wavefront, which originated from a quasi-point source on the front turbid layer and passed through the back turbid layer. And then, because of memory effect, the phase-conjugated wavefront could be used as a carrier wave to transport a pre-calculated wavefront through the back turbid layer. The pre-calculated wavefront could project a desired 3D light field inside the sample, which, in our experiments, consisted of two 220-grid ground glass plates spaced by a 20 mm distance. The controllable range of light, according to the memory effect, was calculated to be 80 mrad in solid angle and 16 mm on z-axis. Due to the 3D light control ability, our approach may find applications in photodynamic therapy and optogenetics. Besides, our approach can also be combined with ghost imaging or compressed sensing to achieve 3D imaging between turbid layers.

Infants Perceive Human Point-Light Displays as Solid Forms

ERIC Educational Resources Information Center

Moore, Derek G.; Goodwin, Julia E.; George, Rachel; Axelsson, Emma L.; Braddick, Fleur M. B.

2007-01-01

While five-month-old infants show orientation-specific sensitivity to changes in the motion and occlusion patterns of human point-light displays, it is not known whether infants are capable of binding a human representation to these displays. Furthermore, it has been suggested that infants do not encode the same physical properties for humans and…

Somatic diversification of chicken immunoglobulin light chains by point mutations.

PubMed

Parvari, R; Ziv, E; Lantner, F; Heller, D; Schechter, I

1990-04-01

The light-chain locus of chicken has 1 functional V lambda 1 gene, 1 J gene, and 25 pseudo-V lambda-genes (where V = variable and J = joining). A major problem is which somatic mechanisms expand this extremely limited germ-line information to generate many different antibodies. Weill's group [Reynaud, C. A., Anquez, V., Grimal, H. & Weill, J. C. (1987) Cell 48, 379-388] has shown that the pseudo-V lambda-genes diversify the rearranged V lambda 1 by gene conversion. Here we demonstrate that chicken light chains are further diversified by somatic point mutations and by V lambda 1-J flexible joining. Somatic point mutations were identified in the J and 3' noncoding DNA of rearranged light-chain genes of chicken. These regions were analyzed because point mutations in V lambda 1 are obscured by gene conversion; the J and 3' noncoding DNA are presented in one copy per haploid genome and are not subject to gene conversion. In rodents point mutations occur as frequently in the V-J coding regions as in the adjacent flanking DNA. Therefore, we conclude that somatic point mutations diversify the V lambda 1 of chicken. The frequency (0-1%) and distribution of the mutations (decreasing in number with increased distance from the V lambda 1 segment) in chicken were as observed in rodents. Sequence variability at the V lambda 1-J junctions could be attributed to imprecise joining of the V lambda 1 and J genes. The modification by gene conversion of rearranged V lambda 1 genes in the bursa was similar in chicken aged 3 months (9.5%) or 3 weeks (9.1%)--i.e., gene conversion that generates the preimmune repertoire in the bursa seems to level off around 3 weeks of age. This preimmune repertoire can be further diversified by somatic point mutations that presumably lead to the formation of antibodies with increased affinity. A segment with structural features of a matrix association region [(A + T)-rich and four topoisomerase II binding sites] was identified in the middle of the J

Biological variability of transferrin saturation and unsaturated iron binding capacity

PubMed Central

Adams, PC; Reboussin, DM; Press, RD; Barton, JC; Acton, RT; Moses, GC; Leiendecker-Foster, C; McLaren, GD; Dawkins, FW; Gordeuk, VR; Lovato, L; Eckfeldt, JH

2007-01-01

Background Transferrin saturation is widely considered the preferred screening test for hemochromatosis. Unsaturated iron binding capacity has similar performance at lower cost. However, the within-person biological variability of both these tests may limit their ability at commonly used cut points to detect HFE C282Y homozygous patients. Methods The Hemochromatosis and Iron Overload Screening (HEIRS) Study screened 101,168 primary care participants for iron overload using tansferrin saturation, unsaturated iron binding capacity, ferritin and HFE C282Y and H63D genotyping. Transferrin saturation and unsaturated iron binding capacity were performed at initial screening and again when selected participants and controls returned for a clinical examination several months later. A missed case was defined as a C282Y homozygote who had transferrin saturation below cut point (45 % women, 50 % men) or unsaturated iron binding capacity above cut point (150 μmol/L women, 125 μmol/L men) at either the initial screening or clinical examination, or both, regardless of serum ferritin. Results There were 209 C282Y previously undiagnosed homozygotes with transferrin saturation and unsaturated iron binding capacity testing done at initial screening and clinical examination. Sixty-eight C282Y homozygotes (33%) would have been missed at these transferrin saturation cut points (19 men, 49 women, median SF 170 μg/L, first and third quartiles 50 and 474 μg/L), and 58 homozygotes (28 %) would have been missed at the unsaturated iron binding capacity cut points (20 men, 38 women, median SF 168 μg/L, quartiles 38 and 454 μg/L). There was no advantage to using fasting samples. Conclusions The within-person biological variability of transferrin saturation and unsaturated iron binding capacity limit their usefulness as an initial screening test for expressing C282Y homozygotes. PMID:17976429

New generalized corresponding states correlation for surface tension of normal saturated liquids

NASA Astrophysics Data System (ADS)

Yi, Huili; Tian, Jianxiang

2015-08-01

A new simple correlation based on the principle of corresponding state is proposed to estimate the temperature-dependent surface tension of normal saturated liquids. The new correlation contains three coefficients obtained by fitting 17,051 surface tension data of 38 saturated normal liquids. These 38 liquids contain refrigerants, hydrocarbons and some other inorganic liquids. The new correlation requires only the triple point temperature, triple point surface tension and critical point temperature as input and is able to well represent the experimental surface tension data for each of the 38 saturated normal liquids from the triple temperature up to the point near the critical point. The new correlation gives absolute average deviations (AAD) values below 3% for all of these 38 liquids with the only exception being octane with AAD=4.30%. Thus, the new correlation gives better overall results in comparison with other correlations for these 38 normal saturated liquids.

Image dehazing based on non-local saturation

NASA Astrophysics Data System (ADS)

Wang, Linlin; Zhang, Qian; Yang, Deyun; Hou, Yingkun; He, Xiaoting

2018-04-01

In this paper, a method based on non-local saturation algorithm is proposed to avoid block and halo effect for single image dehazing with dark channel prior. First we convert original image from RGB color space into HSV color space with the idea of non-local method. Image saturation is weighted equally by the size of fixed window according to image resolution. Second we utilize the saturation to estimate the atmospheric light value and transmission rate. Then through the function of saturation and transmission, the haze-free image is obtained based on the atmospheric scattering model. Comparing the results of existing methods, our method can restore image color and enhance contrast. We guarantee the proposed method with quantitative and qualitative evaluation respectively. Experiments show the better visual effect with high efficiency.

Structures and interactions among globular proteins above the isoelectric point in the presence of divalent ions: A small angle neutron scattering and dynamic light scattering study

NASA Astrophysics Data System (ADS)

Kundu, Sarathi; Pandit, Subhankar; Abbas, Sohrab; Aswal, V. K.; Kohlbrecher, J.

2018-02-01

Small angle neutron scattering study reveals that at pD ≈ 7.0, above the isoelectric point of the globular protein Bovine Serum Albumin (BSA), in the presence of different divalent ions (Mg2+, Ca2+, Sr2+ and Ba2+), the short-range attractive interaction remains nearly constant and the intermediate-range repulsive interaction decreases with increasing salt concentration up to a certain concentration value but after that remains unchanged. However, for the monovalent ion (Na+), repulsive interaction decreases gradually up to 1 M salt concentration. Dynamic light scattering study shows that for all ions, diffusion coefficient of BSA decreases with increasing salt concentration and then nearly saturates.

Effects of temperature and light on photosynthesis of dominant species of a northern hardwood forest. [Populus grandidentata, Quercus rubra, Betula papyrifera

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

Jurik, T.W.; Weber, J.A.; Gates, D.M.

1988-06-01

The response of CO{sub 2} exchange rate (CER) to temperature and light was determined for 14 dominant plant species of a northern deciduous hardwood forest in northern lower Michigan. Leaves at the top of the canopy had temperature optima near 25 C for CER, whereas leaves in the understory had optima near 20 C. There was no change in optimum temperature over the growing season, and overall shapes of response curves were similar among species. The lack of change in temperature optima may be a result of little change in growing conditions rather than a lack of ability to acclimatize.more » Nine of 11 species in the understory had no significant differences in light-saturated, maximum CERs, whereas at the top of the canopy Populus grandidentata had a higher maximum CER than Quercus rubra and Betula papyrifera. The species in the understory also differed little in light-saturation points for CER. Species at the top of the canopy had higher values for maximum CER, light-saturation point for CER, and maximum conductance than did species in the understory.« less

High saturation solar light beam induced current scanning of solar cells.

PubMed

Vorster, F J; van Dyk, E E

2007-01-01

The response of the electrical parameters of photovoltaic cells under concentrated solar irradiance has been the subject of many studies performed in recent times. The high saturation conditions typically found in solar cells that are subjected to highly concentrated solar radiation may cause electrically active cell features to behave differently than under monochromatic laser illumination, normally used in light beam induced current (LBIC) investigations. A high concentration solar LBIC (S-LBIC) measurement system has been developed to perform localized cell characterization. The responses of silicon solar cells that were measured qualitatively include externally biased induced cell current at specific cell voltages, I(V), open circuit voltage, V(oc), and the average rate of change of the cell bias with the induced current, DeltaV/DeltaI(V), close to the zero bias region. These images show the relative scale of the parameters of a cell up to the penetration depth of the solar beam and can be obtained with relative ease, qualifying important electrical response features of the solar cell. The S-LBIC maps were also compared with maps that were similarly obtained using a high intensity He-Ne laser beam probe. This article reports on the techniques employed and initial results obtained.

In vivo detection of hemoglobin oxygen saturation and carboxyhemoglobin saturation with multiwavelength photoacoustic microscopy.

PubMed

Chen, Zhongjiang; Yang, Sihua; Xing, Da

2012-08-15

A method for noninvasively detecting hemoglobin oxygen saturation (SO2) and carboxyhemoglobin saturation (SCO) in subcutaneous microvasculature with multiwavelength photoacoustic microscopy is presented. Blood samples mixed with different concentrations of carboxyhemoglobin were used to test the feasibility and accuracy of photoacoustic microscopy compared with the blood-gas analyzer. Moreover, fixed-point detection of SO2 and SCO in mouse ear was obtained, and the changes from normoxia to carbon monoxide hypoxia were dynamically monitored in vivo. Experimental results demonstrate that multiwavelength photoacoustic microscopy can detect SO2 and SCO, which has future potential clinical applications.

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...

Estimation of saturated pixel values in digital color imaging

PubMed Central

Zhang, Xuemei; Brainard, David H.

2007-01-01

Pixel saturation, where the incident light at a pixel causes one of the color channels of the camera sensor to respond at its maximum value, can produce undesirable artifacts in digital color images. We present a Bayesian algorithm that estimates what the saturated channel's value would have been in the absence of saturation. The algorithm uses the non-saturated responses from the other color channels, together with a multivariate Normal prior that captures the correlation in response across color channels. The appropriate parameters for the prior may be estimated directly from the image data, since most image pixels are not saturated. Given the prior, the responses of the non-saturated channels, and the fact that the true response of the saturated channel is known to be greater than the saturation level, the algorithm returns the optimal expected mean square estimate for the true response. Extensions of the algorithm to the case where more than one channel is saturated are also discussed. Both simulations and examples with real images are presented to show that the algorithm is effective. PMID:15603065

Quantitative imaging and in situ concentration measurements of quantum dot nanomaterials in variably saturated porous media

DOE PAGES

Uyuşur, Burcu; Snee, Preston T.; Li, Chunyan; ...

2016-01-01

Knowledge of the fate and transport of nanoparticles in the subsurface environment is limited, as techniques to monitor and visualize the transport and distribution of nanoparticles in porous media and measure their in situ concentrations are lacking. To address these issues, we have developed a light transmission and fluorescence method to visualize and measure in situ concentrations of quantum dot (QD) nanoparticles in variably saturated environments. Calibration cells filled with sand as porous medium and various known water saturation levels and QD concentrations were prepared. By measuring the intensity of the light transmitted through porous media exposed to fluorescent lightmore » and by measuring the hue of the light emitted by the QDs under UV light exposure, we obtained simultaneously in situ measurements of water saturation and QD nanoparticle concentrations with high spatial and temporal resolutions. Water saturation was directly proportional to the light intensity. A linear relationship was observed between hue-intensity ratio values and QD concentrations for constant water saturation levels. Lastly, the advantages and limitations of the light transmission and fluorescence method as well as its implications for visualizing and measuring in situ concentrations of QDs nanoparticles in the subsurface environment are discussed.« less

Seasonal trends of light-saturated net photosynthesis and stomatal conductance of loblolly pine trees grown in contrasting environments of nutrition, water and carbon dioxide

Treesearch

Ramesh Murthy; Stanley J. Zarnoch; P.M. Dougherty

1997-01-01

Repeated measures analysis was used to evaluate the effect of long-term CO2 enhancement on seasonal trends of light-saturated rates of net photosynthesis (Asat) and stomatal conductance to water vapour (gsat) of 9-year-old loblolly pine (Pinus taeda L.; trees grown in a 2x2...

Non-contact estimation of heart rate and oxygen saturation using ambient light.

PubMed

Bal, Ufuk

2015-01-01

We propose a robust method for automated computation of heart rate (HR) from digital color video recordings of the human face. In order to extract photoplethysmographic signals, two orthogonal vectors of RGB color space are used. We used a dual tree complex wavelet transform based denoising algorithm to reduce artifacts (e.g. artificial lighting, movement, etc.). Most of the previous work on skin color based HR estimation performed experiments with healthy volunteers and focused to solve motion artifacts. In addition to healthy volunteers we performed experiments with child patients in pediatric intensive care units. In order to investigate the possible factors that affect the non-contact HR monitoring in a clinical environment, we studied the relation between hemoglobin levels and HR estimation errors. Low hemoglobin causes underestimation of HR. Nevertheless, we conclude that our method can provide acceptable accuracy to estimate mean HR of patients in a clinical environment, where the measurements can be performed remotely. In addition to mean heart rate estimation, we performed experiments to estimate oxygen saturation. We observed strong correlations between our SpO2 estimations and the commercial oximeter readings.

Non-contact estimation of heart rate and oxygen saturation using ambient light

PubMed Central

Bal, Ufuk

2014-01-01

We propose a robust method for automated computation of heart rate (HR) from digital color video recordings of the human face. In order to extract photoplethysmographic signals, two orthogonal vectors of RGB color space are used. We used a dual tree complex wavelet transform based denoising algorithm to reduce artifacts (e.g. artificial lighting, movement, etc.). Most of the previous work on skin color based HR estimation performed experiments with healthy volunteers and focused to solve motion artifacts. In addition to healthy volunteers we performed experiments with child patients in pediatric intensive care units. In order to investigate the possible factors that affect the non-contact HR monitoring in a clinical environment, we studied the relation between hemoglobin levels and HR estimation errors. Low hemoglobin causes underestimation of HR. Nevertheless, we conclude that our method can provide acceptable accuracy to estimate mean HR of patients in a clinical environment, where the measurements can be performed remotely. In addition to mean heart rate estimation, we performed experiments to estimate oxygen saturation. We observed strong correlations between our SpO2 estimations and the commercial oximeter readings PMID:25657877

Development of an oxygen saturation measuring system by using near-infrared spectroscopy

NASA Astrophysics Data System (ADS)

Kono, K.; Nakamachi, E.; Morita, Y.

2017-08-01

Recently, the hypoxia imaging has been recognized as the advanced technique to detect cancers because of a strong relationship with the biological characterization of cancer. In previous studies, hypoxia imaging systems for endoscopic diagnosis have been developed. However, these imaging technologies using the visible light can observe only blood vessels in gastric mucous membrane. Therefore, they could not detect scirrhous gastric cancer which accounts for 10% of all gastric cancers and spreads rapidly into submucous membrane. To overcome this problem, we developed a measuring system of blood oxygen saturation in submucous membrane by using near-infrared (NIR) spectroscopy. NIR, which has high permeability for bio-tissues and high absorbency for hemoglobin, can image and observe blood vessels in submucous membrane. NIR system with LED lights and a CCD camera module was developed to image blood vessels. We measured blood oxygen saturation using the optical density ratio (ODR) of two wavelengths, based on Lambert-Beer law. To image blood vessel clearly and measure blood oxygen saturation accurately, we searched two optimum wavelengths by using a multilayer human gastric-like phantom which has same optical properties as human gastric one. By using Monte Carlo simulation of light propagation, we derived the relationship between the ODR and blood oxygen saturation and elucidated the influence of blood vessel depth on measuring blood oxygen saturation. The oxygen saturation measuring methodology was validated with experiments using our NIR system. Finally, it was confirmed that our system can detect oxygen saturation in various depth blood vessels accurately.

Local changes in arterial oxygen saturation induced by visible and near-infrared light radiation.

PubMed

Yesman, S S; Mamilov, S O; Veligotsky, D V; Gisbrecht, A I

2016-01-01

In this study, we investigate the efficiency of laser radiation on oxyhemoglobin (HbO2) rate in blood vessels and its wavelength dependence. The results of in vivo experimental measurements of the laser-induced photodissociation of HbO2 in cutaneous blood vessels in the visible and near-infrared (IR) spectral range are presented. Arterial oxygen saturation (SpO2) was measured by a method of fingertip pulse oximetry, which is based on the measurement of the modulated pulse wave of the blood. The light irradiating the finger was provided by corresponding light-emitting diodes (LED) at 15 wavelengths in the 400-940 nm spectrum range. Statistical results with a value of p < 0.05 were viewed as being significant for all volunteers. The results show that there is a decrease in SpO2 in the blood under the influence of the transcutaneous laser irradiation. Three maxima in the spectral range (530, 600, and 850 nm) are revealed, wherein decrease in the relative concentration of SpO2 reaches 5 % ± 0.5 %. Near-IR radiation plays a dominant role in absorption of laser radiation by oxyhemoglobin in deeper layers of tissue blood vessels. The obtained data correlate with the processes of light propagation in biological tissue. The observed reduction in SpO2 indicates the process of photodissociation of HbO2 in vivo and may result in local increase in O2 in the tissue. Such laser-induced enrichment of tissue oxygenation can be used in phototherapy of pathologies, where the elimination of local tissue hypoxia is critical.

Nurse opinions and pulse oximeter saturation target limits for preterm infants.

PubMed

Nghiem, Tuyet-Hang; Hagadorn, James I; Terrin, Norma; Syke, Sally; MacKinnon, Brenda; Cole, Cynthia H

2008-05-01

The objectives of this study were to compare pulse oximeter saturation limits targeted by nurses for extremely preterm infants during routine care with nurse opinions regarding appropriate pulse oximeter saturation limits and with policy-specified pulse oximeter saturation limits and to identify factors that influence pulse oximeter saturation limits targeted by nurses. We surveyed nurses in US NICUs with neonatal-perinatal fellowships in 2004. Data collected included pulse oximeter saturation limits targeted by nurses and by NICU policy when present, nurses' opinions about appropriate pulse oximeter saturation limits, and NICU and nurse characteristics. Factors associated with pulse oximeter saturation limits targeted by nurses were identified with hierarchical linear modeling. Among those eligible, 2805 (45%) nurses in 59 (60%) NICUs responded. Forty (68%) of 59 NICUs had a policy that specified a pulse oximeter saturation target range for extremely preterm infants. Among 1957 nurses at NICUs with policies, 540 (28%) accurately identified the upper and lower limits of their NICU's policy and also targeted these values in practice. NICU-specific SDs for individual nurse target limits were less at NICUs with versus without a policy for both upper and lower limits. Hierarchical linear modeling identified presence of pulse oximeter saturation policy, NICU-specific nurse group opinion, and individual nurse opinion as factors significantly associated with individual pulse oximeter saturation target limits. For each percentage point increase in individual opinion upper limit, the individual target upper limit increased by 0.41 percentage point at NICUs with a policy compared with 0.6 percentage point at NICUs with no policy. Presence of policy-specified pulse oximeter saturation limits, nurse group opinion, and individual nurse opinion were independently associated with individual nurse pulse oximeter saturation target limits during routine care of extremely preterm

Oxygen saturation and perfusion changes during dermatological methylaminolaevulinate photodynamic therapy.

PubMed

Tyrrell, J; Thorn, C; Shore, A; Campbell, S; Curnow, A

2011-12-01

Methylaminolaevulinate (MAL)-photodynamic therapy (PDT) is a successful topical treatment for a number of (pre)cancerous dermatological conditions. In combination, light of the appropriate wavelength, the photosensitizer protoporphyrin IX (PpIX) and tissue oxygen result in the production of singlet oxygen and reactive oxygen species inducing cell death. This study investigates real-time changes in localized tissue blood oxygen saturation and perfusion in conjunction with PpIX fluorescence monitoring for the first time during dermatological MAL-PDT. Oxygen saturation, perfusion and PpIX fluorescence were monitored noninvasively utilizing optical reflectance spectroscopy, laser Doppler perfusion imaging and a fluorescence imaging system, respectively. Patients attending for standard dermatological MAL-PDT were recruited to this ethically approved study and monitored prior to, during and after light irradiation. Significant reductions in mean blood oxygen saturation (P < 0·005) and PpIX fluorescence (P < 0·001) were observed within the first minute of irradiation (4·75 J cm(-2) ) while, in contrast, perfusion was observed to increase significantly (P < 0·01) during treatment. The changes in oxygen saturation and PpIX fluorescence were positively correlated during the initial phase of treatment (r(2) = 0·766). Rapid reductions in the localized blood oxygen saturation have been observed for the first time to occur clinically within the initial minutes of light irradiation and positively correlate with the concurrent PpIX photobleaching. Furthermore, perfusion increases, suggesting that the microvasculature compensates for the PDT-induced oxygen depletion. © 2011 The Authors. BJD © 2011 British Association of Dermatologists 2011.

Invalid-point removal based on epipolar constraint in the structured-light method

NASA Astrophysics Data System (ADS)

Qi, Zhaoshuai; Wang, Zhao; Huang, Junhui; Xing, Chao; Gao, Jianmin

2018-06-01

In structured-light measurement, there unavoidably exist many invalid points caused by shadows, image noise and ambient light. According to the property of the epipolar constraint, because the retrieved phase of the invalid point is inaccurate, the corresponding projector image coordinate (PIC) will not satisfy the epipolar constraint. Based on this fact, a new invalid-point removal method based on the epipolar constraint is proposed in this paper. First, the fundamental matrix of the measurement system is calculated, which will be used for calculating the epipolar line. Then, according to the retrieved phase map of the captured fringes, the PICs of each pixel are retrieved. Subsequently, the epipolar line in the projector image plane of each pixel is obtained using the fundamental matrix. The distance between the corresponding PIC and the epipolar line of a pixel is defined as the invalidation criterion, which quantifies the satisfaction degree of the epipolar constraint. Finally, all pixels with a distance larger than a certain threshold are removed as invalid points. Experiments verified that the method is easy to implement and demonstrates better performance than state-of-the-art measurement systems.

[Effects of different rootstocks on the weak light tolerance ability of summer black grape based on 4 photo-response models].

PubMed

Han, Xiao; Wang, Hai Bo; Wang, Xiao di; Shi, Xiang Bin; Wang, Bao Liang; Zheng, Xiao Cui; Wang, Zhi Qiang; Liu, Feng Zhi

2017-10-01

The photo response curves of 11 rootstock-scion combinations including summer black/Beta, summer black/1103P, summer black/101-14, summer black/3309C, summer black/140Ru, summer black/5C, summer black/5BB, summer black/420A, summer black/SO4, summer black/Kangzhen No.1, summer black/Huapu No.1 were fitted by rectangular hyperbola mo-del, non-rectangular hyperbola model, modified rectangular hyperbola model and exponential model respectively, and the differences of imitative effects were analyzed by determination coefficiency, light compensation point, light saturation point, initial quantum efficiency, maximum photosynthetic rate and dark respiration rate. The result showed that the fit coefficients of all four models were above 0.98, and there was no obvious difference on the fitted values of light compensation point among the four models. The modified rectangular hyperbola model fitted best on light saturation point, apparent quantum yield, maximum photosynthetic rate and dark respiration rate, and had the minimum AIC value based on the akaike information criterion, therefore, the modified rectangular hyperbola model was the best one. The clustering analysis indicated that summer black/SO4 and summer black/420A combinations had low light compensation point, high apparent quantum yield and low dark respiration rate among 11 rootstock-scion combinations, suggesting that these two combinations could use weak light more efficiently due to their less respiratory consumption and higher weak light tolerance. The Topsis comparison method ranked summer black/SO4 and summer black/420A combinations as No. 1 and No. 2 respectively in weak light tolerance ability, which was consistent with cluster analysis. Consequently, summer black has the highest weak light tolerance in case grafted on 420A or SO4, which could be the most suitable rootstock-scion combinations for protected cultivation.

Corresponding states correlation for temperature dependent surface tension of normal saturated liquids

NASA Astrophysics Data System (ADS)

Yi, Huili; Tian, Jianxiang

2014-07-01

A new simple correlation based on the principle of corresponding state is proposed to estimate the temperature-dependent surface tension of normal saturated liquids. The correlation is a linear one and strongly stands for 41 saturated normal liquids. The new correlation requires only the triple point temperature, triple point surface tension and critical point temperature as input and is able to represent the experimental surface tension data for these 41 saturated normal liquids with a mean absolute average percent deviation of 1.26% in the temperature regions considered. For most substances, the temperature covers the range from the triple temperature to the one beyond the boiling temperature.

Arterial blood oxygen saturation during blood pressure cuff-induced hypoperfusion

NASA Astrophysics Data System (ADS)

Kyriacou, P. A.; Shafqat, K.; Pal, S. K.

2007-10-01

Pulse oximetry has been one of the most significant technological advances in clinical monitoring in the last two decades. Pulse oximetry is a non-invasive photometric technique that provides information about the arterial blood oxygen saturation (SpO2) and heart rate, and has widespread clinical applications. When peripheral perfusion is poor, as in states of hypovolaemia, hypothermia and vasoconstriction, oxygenation readings become unreliable or cease. The problem arises because conventional pulse oximetry sensors must be attached to the most peripheral parts of the body, such as finger, ear or toe, where pulsatile flow is most easily compromised. Pulse oximeters estimate arterial oxygen saturation by shining light at two different wavelengths, red and infrared, through vascular tissue. In this method the ac pulsatile photoplethysmographic (PPG) signal associated with cardiac contraction is assumed to be attributable solely to the arterial blood component. The amplitudes of the red and infrared ac PPG signals are sensitive to changes in arterial oxygen saturation because of differences in the light absorption of oxygenated and deoxygenated haemoglobin at these two wavelengths. From the ratios of these amplitudes, and the corresponding dc photoplethysmographic components, arterial blood oxygen saturation (SpO2) is estimated. Hence, the technique of pulse oximetry relies on the presence of adequate peripheral arterial pulsations, which are detected as photoplethysmographic (PPG) signals. The aim of this study was to investigate the effect of pressure cuff-induced hypoperfusion on photoplethysmographic signals and arterial blood oxygen saturation using a custom made finger blood oxygen saturation PPG/SpO2 sensor and a commercial finger pulse oximeter. Blood oxygen saturation values from the custom oxygen saturation sensor and a commercial finger oxygen saturation sensor were recorded from 14 healthy volunteers at various induced brachial pressures. Both pulse

Multi-Point Interferometric Rayleigh Scattering using Dual-Pass Light Recirculation

NASA Technical Reports Server (NTRS)

Bivolaru, Daniel; Danehy, Paul M.; Cutler, Andrew D.

2008-01-01

This paper describes for the first time an interferometric Rayleigh scattering system using dual-pass light recirculation (IRS-LR) capable of simultaneously measuring at multiple points two orthogonal components of flow velocity in combustion flows using single shot laser probing. An additional optical path containing the interferometer input mirror, a quarter-wave plate, a polarization dependent beam combiner, and a high reflectivity mirror partially recirculates the light that is rejected by the interferometer. Temporally- and spatially-resolved acquisitions of Rayleigh spectra in a large-scale combustion-heated supersonic axi-symmetric jet were performed to demonstrate the technique. Recirculating of Rayleigh scattered light increases the number of photons analyzed by the system up to a factor of 1.8 compared with previous configurations. This is equivalent to performing measurements with less laser energy or performing measurements with the previous system in gas flows at higher temperatures.

Effects of skin pigmentation on pulse oximeter accuracy at low saturation.

PubMed

Bickler, Philip E; Feiner, John R; Severinghaus, John W

2005-04-01

It is uncertain whether skin pigmentation affects pulse oximeter accuracy at low HbO2 saturation. The accuracy of finger pulse oximeters during stable, plateau levels of arterial oxygen saturation (Sao2) between 60 and 100% were evaluated in 11 subjects with darkly pigmented skin and in 10 with light skin pigmentation. Oximeters tested were the Nellcor N-595 with the OxiMax-A probe (Nellcor Inc., Pleasanton, CA), the Novametrix 513 (Novametrix Inc., Wallingford, CT), and the Nonin Onyx (Nonin Inc., Plymouth, MN). Semisupine subjects breathed air-nitrogen-carbon dioxide mixtures through a mouthpiece. A computer used end-tidal oxygen and carbon dioxide concentrations determined by mass spectrometry to estimate breath-by-breath Sao2, from which an operator adjusted inspired gas to rapidly achieve 2- to 3-min stable plateaus of desaturation. Comparisons of oxygen saturation measured by pulse oximetry (Spo2) with Sao2 (by Radiometer OSM3) were used in a multivariate model to determine the interrelation between saturation, skin pigmentation, and oximeter bias (Spo2 - Sao2). At 60-70% Sao2, Spo2 (mean of three oximeters) overestimated Sao2 (bias +/- SD) by 3.56 +/- 2.45% (n = 29) in darkly pigmented subjects, compared with 0.37 +/- 3.20% (n = 58) in lightly pigmented subjects (P < 0.0001). The SD of bias was not greater with dark than light skin. The dark-light skin differences at 60-70% Sao2 were 2.35% (Nonin), 3.38% (Novametrix), and 4.30% (Nellcor). Skin pigment-related differences were significant with Nonin below 70% Sao2, with Novametrix below 90%, and with Nellcor at all ranges. Pigment-related bias increased approximately in proportion to desaturation. The three tested pulse oximeters overestimated arterial oxygen saturation during hypoxia in dark-skinned individuals.

Pattern formation in a liquid-crystal light valve with feedback, including polarization, saturation, and internal threshold effects

NASA Astrophysics Data System (ADS)

Neubecker, R.; Oppo, G.-L.; Thuering, B.; Tschudi, T.

1995-07-01

The use of liquid-crystal light valves (LCLV's) as nonlinear elements in diffractive optical systems with feedback leads to the formation of a variety of optical patterns. The spectrum of possible spatial instabilities is shown to be even richer when the LCLV's capability for polarization modulation is utilized and internal threshold and saturation effects are considered. We derive a model for the feedback system based on a realistic description of the LCLV's internal function and coupling to a polarizer. Thresholds of pattern formation are compared to the common Kerr-type approximation and show transitions involving rolls, squares, hexagons, and tiled patterns. Numerical and experimental results confirm our theoretical predictions and unveil how patterns and their typical length scales can be easily controlled by changes of the parameters.

Graphene-clad microfibre saturable absorber for ultrafast fibre lasers

PubMed Central

Liu, X. M.; Yang, H. R.; Cui, Y. D.; Chen, G. W.; Yang, Y.; Wu, X. Q.; Yao, X. K.; Han, D. D.; Han, X. X.; Zeng, C.; Guo, J.; Li, W. L.; Cheng, G.; Tong, L. M.

2016-01-01

Graphene, whose absorbance is approximately independent of wavelength, allows broadband light–matter interactions with ultrafast responses. The interband optical absorption of graphene can be saturated readily under strong excitation, thereby enabling scientists to exploit the photonic properties of graphene to realize ultrafast lasers. The evanescent field interaction scheme of the propagating light with graphene covered on a D-shaped fibre or microfibre has been employed extensively because of the nonblocking configuration. Obviously, most of the fibre surface is unused in these techniques. Here, we exploit a graphene-clad microfibre (GCM) saturable absorber in a mode-locked fibre laser for the generation of ultrafast pulses. The proposed all-surface technique can guarantee a higher efficiency of light–graphene interactions than the aforementioned techniques. Our GCM-based saturable absorber can generate ultrafast optical pulses within 1.5 μm. This saturable absorber is compatible with current fibre lasers and has many merits such as low saturation intensities, ultrafast recovery times, and wide wavelength ranges. The proposed saturable absorber will pave the way for graphene-based wideband photonics. PMID:27181419

The Signer and the Sign: Cortical Correlates of Person Identity and Language Processing from Point-Light Displays

ERIC Educational Resources Information Center

Campbell, Ruth; Capek, Cheryl M.; Gazarian, Karine; MacSweeney, Mairead; Woll, Bencie; David, Anthony S.; McGuire, Philip K.; Brammer, Michael J.

2011-01-01

In this study, the first to explore the cortical correlates of signed language (SL) processing under point-light display conditions, the observer identified either a signer or a lexical sign from a display in which different signers were seen producing a number of different individual signs. Many of the regions activated by point-light under these…

Multipactor saturation in parallel-plate waveguides

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

Sorolla, E.; Mattes, M.

2012-07-15

The saturation stage of a multipactor discharge is considered of interest, since it can guide towards a criterion to assess the multipactor onset. The electron cloud under multipactor regime within a parallel-plate waveguide is modeled by a thin continuous distribution of charge and the equations of motion are calculated taking into account the space charge effects. The saturation is identified by the interaction of the electron cloud with its image charge. The stability of the electron population growth is analyzed and two mechanisms of saturation to explain the steady-state multipactor for voltages near above the threshold onset are identified. Themore » impact energy in the collision against the metal plates decreases during the electron population growth due to the attraction of the electron sheet on the image through the initial plate. When this growth remains stable till the impact energy reaches the first cross-over point, the electron surface density tends to a constant value. When the stability is broken before reaching the first cross-over point the surface charge density oscillates chaotically bounded within a certain range. In this case, an expression to calculate the maximum electron surface charge density is found whose predictions agree with the simulations when the voltage is not too high.« less

HPLC-DAD-ESI/MS identification of light harvesting and light screening pigments in the lake sediments at Edmonson Point.

PubMed

Giovannetti, Rita; Alibabaei, Leila; Zannotti, Marco; Ferraro, Stefano; Petetta, Laura

2013-01-01

The composition of sedimentary pigments in the Antarctic lake at Edmonson Point has been investigated and compared with the aim to provide a useful analytical method for pigments separation and identification, providing reference data for future assessment of possible changes in environmental conditions. Reversed phase high performance liquid chromatography (HPLC) with electrospray-mass spectrometry (ESI-MS) detection and diode array detection (DAD) has been used to identify light screening and light harvesting pigments. The results are discussed in terms of local environmental conditions.

Code Saturation Versus Meaning Saturation: How Many Interviews Are Enough?

PubMed

Hennink, Monique M; Kaiser, Bonnie N; Marconi, Vincent C

2017-03-01

Saturation is a core guiding principle to determine sample sizes in qualitative research, yet little methodological research exists on parameters that influence saturation. Our study compared two approaches to assessing saturation: code saturation and meaning saturation. We examined sample sizes needed to reach saturation in each approach, what saturation meant, and how to assess saturation. Examining 25 in-depth interviews, we found that code saturation was reached at nine interviews, whereby the range of thematic issues was identified. However, 16 to 24 interviews were needed to reach meaning saturation where we developed a richly textured understanding of issues. Thus, code saturation may indicate when researchers have "heard it all," but meaning saturation is needed to "understand it all." We used our results to develop parameters that influence saturation, which may be used to estimate sample sizes for qualitative research proposals or to document in publications the grounds on which saturation was achieved.

Recognizing Biological Motion and Emotions from Point-Light Displays in Autism Spectrum Disorders

PubMed Central

Nackaerts, Evelien; Wagemans, Johan; Helsen, Werner; Swinnen, Stephan P.; Wenderoth, Nicole; Alaerts, Kaat

2012-01-01

One of the main characteristics of Autism Spectrum Disorder (ASD) are problems with social interaction and communication. Here, we explored ASD-related alterations in ‘reading’ body language of other humans. Accuracy and reaction times were assessed from two observational tasks involving the recognition of ‘biological motion’ and ‘emotions’ from point-light displays (PLDs). Eye movements were recorded during the completion of the tests. Results indicated that typically developed-participants were more accurate than ASD-subjects in recognizing biological motion or emotions from PLDs. No accuracy differences were revealed on two control-tasks (involving the indication of color-changes in the moving point-lights). Group differences in reaction times existed on all tasks, but effect sizes were higher for the biological and emotion recognition tasks. Biological motion recognition abilities were related to a person’s ability to recognize emotions from PLDs. However, ASD-related atypicalities in emotion recognition could not entirely be attributed to more basic deficits in biological motion recognition, suggesting an additional ASD-specific deficit in recognizing the emotional dimension of the point light displays. Eye movements were assessed during the completion of tasks and results indicated that ASD-participants generally produced more saccades and shorter fixation-durations compared to the control-group. However, especially for emotion recognition, these altered eye movements were associated with reductions in task-performance. PMID:22970227

Recognizing biological motion and emotions from point-light displays in autism spectrum disorders.

PubMed

Nackaerts, Evelien; Wagemans, Johan; Helsen, Werner; Swinnen, Stephan P; Wenderoth, Nicole; Alaerts, Kaat

2012-01-01

One of the main characteristics of Autism Spectrum Disorder (ASD) are problems with social interaction and communication. Here, we explored ASD-related alterations in 'reading' body language of other humans. Accuracy and reaction times were assessed from two observational tasks involving the recognition of 'biological motion' and 'emotions' from point-light displays (PLDs). Eye movements were recorded during the completion of the tests. Results indicated that typically developed-participants were more accurate than ASD-subjects in recognizing biological motion or emotions from PLDs. No accuracy differences were revealed on two control-tasks (involving the indication of color-changes in the moving point-lights). Group differences in reaction times existed on all tasks, but effect sizes were higher for the biological and emotion recognition tasks. Biological motion recognition abilities were related to a person's ability to recognize emotions from PLDs. However, ASD-related atypicalities in emotion recognition could not entirely be attributed to more basic deficits in biological motion recognition, suggesting an additional ASD-specific deficit in recognizing the emotional dimension of the point light displays. Eye movements were assessed during the completion of tasks and results indicated that ASD-participants generally produced more saccades and shorter fixation-durations compared to the control-group. However, especially for emotion recognition, these altered eye movements were associated with reductions in task-performance.

Automatic Suppression of Intense Monochromatic Light in Electro-Optical Sensors

PubMed Central

Ritt, Gunnar; Eberle, Bernd

2012-01-01

Electro-optical imaging sensors are widely distributed and used for many different tasks. Due to technical improvements, their pixel size has been steadily decreasing, resulting in a reduced saturation capacity. As a consequence, this progress makes them susceptible to intense point light sources. Developments in laser technology have led to very compact and powerful laser sources of any wavelength in the visible and near infrared spectral region, offered as laser pointers. The manifold of wavelengths makes it difficult to encounter sensor saturation over the complete operating waveband by conventional measures like absorption or interference filters. We present a concept for electro-optical sensors to suppress overexposure in the visible spectral region. The key element of the concept is a spatial light modulator in combination with wavelength multiplexing. This approach allows spectral filtering within a localized area in the field of view of the sensor. The system offers the possibility of automatic reduction of overexposure by monochromatic laser radiation. PMID:23202039

Dark Light, Rod Saturation, and the Absolute and Incremental Sensitivity of Mouse Cone Vision

PubMed Central

Naarendorp, Frank; Esdaille, Tricia M.; Banden, Serenity M.; Andrews-Labenski, John; Gross, Owen P.; Pugh, Edward N.

2012-01-01

Visual thresholds of mice for the detection of small, brief targets were measured with a novel behavioral methodology in the dark and in the presence of adapting lights spanning ∼8 log10 units of intensity. To help dissect the contributions of rod and cone pathways, both wild-type mice and mice lacking rod (Gnat1−/−) or cone (Gnat2cpfl3) function were studied. Overall, the visual sensitivity of mice was found to be remarkably similar to that of the human peripheral retina. Rod absolute threshold corresponded to 12-15 isomerized pigment molecules (R*) in image fields of 800 to 3000 rods. Rod “dark light” (intrinsic retinal noise in darkness) corresponded to that estimated previously from single-cell recordings, 0.012R*s−1rod−1, indicating that spontaneous thermalisomerizations are responsible. Psychophysical rod saturation was measured for the first time in a nonhman species and found to be very similar to that of the human rod monochromat. Cone threshold corresponded to ∼5 R* cone−1 in an image field of 280 cones. Cone dark light was equivalent to ∼5000 R*s−1 cone−1, consistent with primate single-cell data but 100-fold higher than predicted by recent measurements of the rate of thermal isomerization of mouse cone opsins, indicating that nonopsin sources of noise determine cone threshold. The new, fully automated behavioral method is based on the ability of mice to learn to interrupt spontaneous wheel running on the presentation of a visual cue and provides an efficient and highly reliable means of examining visual function in naturally behaving normal and mutant mice. PMID:20844144

New method of extracting information of arterial oxygen saturation based on ∑ | 𝚫 |

NASA Astrophysics Data System (ADS)

Dai, Wenting; Lin, Ling; Li, Gang

2017-04-01

Noninvasive detection of oxygen saturation with near-infrared spectroscopy has been widely used in clinics. In order to further enhance its detection precision and reliability, this paper proposes a method of time domain absolute difference summation (∑|Δ|) based on a dynamic spectrum. In this method, the ratio of absolute differences between intervals of two differential sampling points at the same moment on logarithm photoplethysmography signals of red and infrared light was obtained in turn, and then they obtained a ratio sequence which was screened with a statistical method. Finally, use the summation of the screened ratio sequence as the oxygen saturation coefficient Q. We collected 120 reference samples of SpO2 and then compared the result of two methods, which are ∑|Δ| and peak-peak. Average root-mean-square errors of the two methods were 3.02% and 6.80%, respectively, in the 20 cases which were selected randomly. In addition, the average variance of Q of the 10 samples, which were obtained by the new method, reduced to 22.77% of that obtained by the peak-peak method. Comparing with the commercial product, the new method makes the results more accurate. Theoretical and experimental analysis indicates that the application of the ∑|Δ| method could enhance the precision and reliability of oxygen saturation detection in real time.

New method of extracting information of arterial oxygen saturation based on ∑|𝚫 |

NASA Astrophysics Data System (ADS)

Wenting, Dai; Ling, Lin; Gang, Li

2017-04-01

Noninvasive detection of oxygen saturation with near-infrared spectroscopy has been widely used in clinics. In order to further enhance its detection precision and reliability, this paper proposes a method of time domain absolute difference summation (∑|Δ|) based on a dynamic spectrum. In this method, the ratio of absolute differences between intervals of two differential sampling points at the same moment on logarithm photoplethysmography signals of red and infrared light was obtained in turn, and then they obtained a ratio sequence which was screened with a statistical method. Finally, use the summation of the screened ratio sequence as the oxygen saturation coefficient Q. We collected 120 reference samples of SpO2 and then compared the result of two methods, which are ∑|Δ| and peak-peak. Average root-mean-square errors of the two methods were 3.02% and 6.80%, respectively, in the 20 cases which were selected randomly. In addition, the average variance of Q of the 10 samples, which were obtained by the new method, reduced to 22.77% of that obtained by the peak-peak method. Comparing with the commercial product, the new method makes the results more accurate. Theoretical and experimental analysis indicates that the application of the ∑|Δ| method could enhance the precision and reliability of oxygen saturation detection in real time.

Measuring hemoglobin amount and oxygen saturation of skin with advancing age

NASA Astrophysics Data System (ADS)

Watanabe, Shumpei; Yamamoto, Satoshi; Yamauchi, Midori; Tsumura, Norimichi; Ogawa-Ochiai, Keiko; Akiba, Tetsuo

2012-03-01

We measured the oxygen saturation of skin at various ages using our previously proposed method that can rapidly simulate skin spectral reflectance with high accuracy. Oxygen saturation is commonly measured by a pulse oximeter to evaluate oxygen delivery for monitoring the functions of heart and lungs at a specific time. On the other hand, oxygen saturation of skin is expected to assess peripheral conditions. Our previously proposed method, the optical path-length matrix method (OPLM), is based on a Monte Carlo for multi-layered media (MCML), but can simulate skin spectral reflectance 27,000 times faster than MCML. In this study, we implemented an iterative simulation of OPLM with a nonlinear optimization technique such that this method can also be used for estimating hemoglobin concentration and oxygen saturation from the measured skin spectral reflectance. In the experiments, the skin reflectance spectra of 72 outpatients aged between 20 and 86 years were measured by a spectrophotometer. Three points were measured for each subject: the forearm, the thenar eminence, and the intermediate phalanx. The result showed that the oxygen saturation of skin remained constant at each point as the age varied.

Synergistic effects of abiotic stresses in plants: a case study of nitrogen limitation and saturating light intensity in Arabidopsis thaliana.

PubMed

Cohen, Itay; Rapaport, Tal; Chalifa-Caspi, Vered; Rachmilevitch, Shimon

2018-05-22

Under natural conditions, plants are regularly exposed to combinations of stress factors. A common example is the conjunction between nitrogen (N) deficiency and excess light. The combined effect of stress factors is often ignored in studies using controlled conditions, possibly resulting in misleading conclusions. To address this issue, the current study examined the physiological behavior of Arabidopsis thaliana under the effect of varying nitrogen levels and light intensities. The joint influence of low N and excess light had an adverse effect on plant growth, chlorophyll and anthocyanin concentrations, photochemical capacity, and the abundance of proteins involved in carbon assimilation and anti-oxidative metabolism. In contrast, no adverse physiological responses were observed for plants under either nitrogen limitation or high light intensity conditions (i.e., single stress). The underline mechanisms for the increased growth in conditions of high light and sufficient nitrogen was due to a combination of chlorophyll accumulation and an increased number of proteins involved in C3 carbon assimilation, amino acids biosynthesis and chloroplast development. In contrast, combined stress conditions caused anthocyanin accumulation and increased number proteins involved in catabolism of lipids and amino acids as energy substrates. Ultimately switching plants from growth to survival. Our results suggest that an assessment of the physiological response to the combined effect of multiple stresses cannot be directly extrapolated from the physiological response to a single stress. Specifically, the synergistic interaction between N deficiency and saturating light in Arabidopsis plants could not have been modeled via only one of the stress factors. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Optical spectroscopy and microscopy of radiation-induced light-emitting point defects in lithium fluoride crystals and films

NASA Astrophysics Data System (ADS)

Montereali, R. M.; Bonfigli, F.; Menchini, F.; Vincenti, M. A.

2012-08-01

Broad-band light-emitting radiation-induced F2 and F3+ electronic point defects, which are stable and laser-active at room temperature in lithium fluoride crystals and films, are used in dosimeters, tuneable color-center lasers, broad-band miniaturized light sources and novel radiation imaging detectors. A brief review of their photoemission properties is presented, and their behavior at liquid nitrogen temperatures is discussed. Some experimental data from optical spectroscopy and fluorescence microscopy of these radiation-induced point defects in LiF crystals and thin films are used to obtain information about the coloration curves, the efficiency of point defect formation, the effects of photo-bleaching processes, etc. Control of the local formation, stabilization, and transformation of radiation-induced light-emitting defect centers is crucial for the development of optically active micro-components and nanostructures. Some of the advantages of low temperature measurements for novel confocal laser scanning fluorescence microscopy techniques, widely used for spatial mapping of these point defects through the optical reading of their visible photoluminescence, are highlighted.

Young Infants Detect the Direction of Biological Motion in Point-Light Displays

ERIC Educational Resources Information Center

Kuhlmeier, Valerie A.; Troje, Nikolaus F.; Lee, Vivian

2010-01-01

In the present study, we examined if young infants can extract information regarding the directionality of biological motion. We report that 6-month-old infants can differentiate leftward and rightward motions from a movie depicting the sagittal view of an upright human point-light walker, walking as if on a treadmill. Inversion of the stimuli…

eLISA Telescope In-field Pointing and Scattered Light Study

NASA Astrophysics Data System (ADS)

Livas, J.; Sankar, S.; West, G.; Seals, L.; Howard, J.; Fitzsimons, E.

2017-05-01

The orbital motion of the three spacecraft that make up the eLISA Observatory constellation causes long-arm line of sight variations of approximately ± one degree over the course of a year. The baseline solution is to package the telescope, the optical bench, and the gravitational reference sensor (GRS) into an optical assembly at each end of the measurement arm, and then to articulate the assembly. An optical phase reference is exchanged between the moving optical benches with a single mode optical fiber (“backlink” fiber). An alternative solution, referred to as in-field pointing, embeds a steering mirror into the optical design, fixing the optical benches and eliminating the backlink fiber, but requiring the additional complication of a two-stage optical design for the telescope. We examine the impact of an in-field pointing design on the scattered light performance.

A New Primary Dew-Point Generator at TUBITAK UME

NASA Astrophysics Data System (ADS)

Oğuz Aytekin, S.; Karaböce, N.; Heinonen, M.; Sairanen, H.

2018-05-01

An implementation of a new low-range primary humidity generator as a part of an international collaboration between TUBITAK UME and VTT MIKES was initiated as a EURAMET Project Number 1259. The dew-point generator was designed and constructed within the scope of the cooperation between TUBITAK UME and VTT MIKES in order to extend the dew-point temperature measurement capability of Humidity Laboratory of TUBITAK UME down to - 80 °C. The system was thoroughly characterized and validated at TUBITAK UME to support the evidence for dew-point temperature uncertainties. The new generator has a capability of operating in the range of - 80 °C to +10 °C, but at the moment, it was characterized down to - 60 °C. The core of the generator system is a saturator which is fully immersed in a liquid bath. Dry air is supplied to the saturator through a temperature-controlled pre-saturator. The operation of the system is based on the single-pressure generation method with a single pass, i.e., the dew-point temperature is only controlled by the saturator temperature, and the humidity-controlled air is not returned to the system after leaving of the saturator. The metrological performance of the saturator was investigated thoroughly at both National Metrology Institutes. The pre-saturator was also tested using a thermostatic bath at VTT MIKES prior to sending them to TUBITAK UME. This paper describes the principle and design of the generator in detail. The dew-point measurement system and the corresponding uncertainty analysis of the dew-point temperature scale realized with the generator in the range from - 60 °C to 10 °C is also presented.

The serpentine optical waveguide: engineering the dispersion relations and the stopped light points.

PubMed

Scheuer, Jacob; Weiss, Ori

2011-06-06

We present a study a new type of optical slow-light structure comprising a serpentine shaped waveguide were the loops are coupled. The dispersion relation, group velocity and GVD are studied analytically using a transfer matrix method and numerically using finite difference time domain simulations. The structure exhibits zero group velocity points at the ends of the Brillouin zone, but also within the zone. The position of mid-zone zero group velocity point can be tuned by modifying the coupling coefficient between adjacent loops. Closed-form analytic expressions for the dispersion relations, group velocity and the mid-zone zero v(g) points are found and presented.

Infant brain activity while viewing facial movement of point-light displays as measured by near-infrared spectroscopy (NIRS).

PubMed

Ichikawa, Hiroko; Kanazawa, So; Yamaguchi, Masami K; Kakigi, Ryusuke

2010-09-27

Adult observers can quickly identify specific actions performed by an invisible actor from the points of lights attached to the actor's head and major joints. Infants are also sensitive to biological motion and prefer to see it depicted by a dynamic point-light display. In detecting biological motion such as whole body and facial movements, neuroimaging studies have demonstrated the involvement of the occipitotemporal cortex, including the superior temporal sulcus (STS). In the present study, we used the point-light display technique and near-infrared spectroscopy (NIRS) to examine infant brain activity while viewing facial biological motion depicted in a point-light display. Dynamic facial point-light displays (PLD) were made from video recordings of three actors making a facial expression of surprise in a dark room. As in Bassili's study, about 80 luminous markers were scattered over the surface of the actor's faces. In the experiment, we measured infant's hemodynamic responses to these displays using NIRS. We hypothesized that infants would show different neural activity for upright and inverted PLD. The responses were compared to the baseline activation during the presentation of individual still images, which were frames extracted from the dynamic PLD. We found that the concentration of oxy-Hb increased in the right temporal area during the presentation of the upright PLD compared to that of the baseline period. This is the first study to demonstrate that infant's brain activity in face processing is induced only by the motion cue of facial movement depicted by dynamic PLD. (c) 2010 Elsevier Ireland Ltd. All rights reserved.

Imaging of biophoton emission from electrostimulated skin acupuncture point jg4: effect of light enhancers.

PubMed

Slawinski, Janusz; Gorski, Zbigniew

2008-05-01

Using an ultrasensitive CCD camera, an extremely low light intensity from the acupuncture-sensitive point JG4 at the left hand was recorded. As the intensity of the light was very weak and the time of electrostimulation exceeded the recommended period, the quality of biophoton images was poor. Chemiluminescent and fluorescent hydrophilic, hydrophobic and amphyphilic molecular probes were used to: (i) ensure penetration of probes into skin, (ii) enhance the intensity of BP emission, (iii) shorten time and (iv) obtain information about mechanisms of biophotons generation in EAP-sensitive points and channels. The results obtained partially fulfilled expectations and indicate on the necessity to elaborate special techniques of probes deposition on the skin.

High strain rate behavior of saturated and non-saturated sandstone: implications for earthquake mechanisms.

NASA Astrophysics Data System (ADS)

Aben, F. M.; Doan, M. L.; Gratier, J. P.; Renard, F.

2015-12-01

Damage zones of active faults control their resistance to rupture and transport properties. Hence, knowing the damage's origin is crucial to shed light on the (paleo)seismic behavior of the fault. Coseismic damage in the damage zone occurs by stress-wave loading of a passing earthquake rupture tip, resulting in dynamic (high strain rate) loading and subsequent dynamic fracturing or pulverization. Recently, interest in this type of damage has increased and several experimental studies were performed on dry rock specimens to search for pulverization-controlling parameters. However, the influence of fluids in during dynamic loading needs to be constrained. Hence, we have performed compressional dynamic loading experiments on water saturated and oven dried Vosges sandstone samples using a Split Hopkinson Pressure Bar apparatus. Due to the high porosity in these rocks, close to 20%, the effect of fluids should be clear. Afterwards, microstructural analyses have been applied on thin sections. Water saturated samples reveal dynamic mechanical behavior that follows linear poro-elasticity for undrained conditions: the peak strength of the sample decreases by 30-50% and the accumulated strain increases relative to the dry samples that were tested under similar conditions. The mechanical behavior of partially saturated samples falls in between. Microstructural studies on thin section show that fractures are restricted to some quartz grains while other quartz grains remain intact, similar to co-seismically damaged sandstones observed in the field. Most deformation is accommodated by inter-granular processes, thereby appointing an important role to the cement matrix in between grains. Intra-granular fracture damage is highest for the saturated samples. The presence of pore fluids in the rocks lower the dynamic peak strength, especially since fast dynamic loading does not allow for time-dependent fluid dissipation. Thus, fluid-saturated rocks would show undrained mechanical

75 FR 4426 - Florida Power and Light Company; Turkey Point Nuclear Generating Units 3 and 4; Environmental...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-27

... Light Company; Turkey Point Nuclear Generating Units 3 and 4; Environmental Assessment and Finding of No... (the licensee), for operation of the Turkey Point Units 3 and 4, located in Miami, Florida. In...-ductility temperature) of the Linde 80 weld materials present in the beltline region of the Turkey Point...

Perceived Intensity of Emotional Point-Light Displays Is Reduced in Subjects with ASD

ERIC Educational Resources Information Center

Krüger, Britta; Kaletsch, Morten; Pilgramm, Sebastian; Schwippert, Sven-Sören; Hennig, Jürgen; Stark, Rudolf; Lis, Stefanie; Gallhofer, Bernd; Sammer, Gebhard; Zentgraf, Karen; Munzert, Jörn

2018-01-01

One major characteristic of autism spectrum disorder (ASD) is problems with social interaction and communication. The present study explored ASD-related alterations in perceiving emotions expressed via body movements. 16 participants with ASD and 16 healthy controls observed video scenes of human interactions conveyed by point-light displays. They…

The viscosity of the refrigerant 1,1-difluoroethane along the saturation line

NASA Astrophysics Data System (ADS)

van der Gulik, P. S.

1993-07-01

The viscosity coefficient of the refrigerant R152a (1,1-difluoroethane) has been measured along the saturation line both in the saturated liquid and in the saturated vapor. The data have been obtained every 10 K from 243 up to 393 K by means of a vibrating-wire viscometer using the free damped oscillation method. The density along the saturation line was calculated from the equation of state given by Tamatsu et al. with application of the saturated vapor-pressure correlation given by Higashi et al. An interesting result is that in the neighborhood of the critical point, the kinematic viscosity of the saturated liquid seems to coincide with that of the saturated vapor. The results for the saturated liquid are in satisfying agreement with those of Kumagai and Takahashi and of Phillips and Murphy. A comparison of the saturatedvaport data with the unsaturated-vapor data of Takahashi et al. shows some discrepancies.

75 FR 34776 - Florida Power & Light Company; Turkey Point Nuclear Generating Plant, Units 3 and 4...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-18

... changes to the reactor, fuel, plant, structures, support structures, water, or land at the Turkey Point... NUCLEAR REGULATORY COMMISSION [Docket Nos. 50-250 and 50-251; NRC-2010-0212] Florida Power & Light Company; Turkey Point Nuclear Generating Plant, Units 3 and 4; Environmental Assessment and Finding of No...

Diurnal Patterns of Direct Light Extinction in Two Tropical Forest Canopies

NASA Astrophysics Data System (ADS)

Cushman, K.; Silva, C. E.; Kellner, J. R.

2016-12-01

The extent to which net ecosystem production is light-limited in Neotropical forests is poorly understood. This is due in part to our limited knowledge of how light moves through complex canopies to different layers of leaves, and the extent to which structural changes in canopies modify the amount of light absorbed by the landscape to drive photosynthesis. Systematic diurnal changes in solar angle, leaf angle, and wind speed suggest that patterns of light attenuation change over the course of the day in tropical forests. In this study, we characterize the extinction of direct light through the canopies of two forests in Panama using high-resolution, three-dimensional measurements from a small footprint, discrete return airborne laser scanner mounted on the gondola of a canopy crane. We hypothesized that light penetrates deeper into canopies during the middle of the day because changes in leaf angle by light-saturated leaves temporarily reduce effective canopy leaf area, and because greater wind speeds increase sunflecks. Also, we hypothesized that rates of light extinction are greater in the wetter forest that receives less direct sunlight because light saturation in upper leaves is less prevalent. We collected laser measurements with resolution of approximately 5,000 points per square meter of ground every 90 minutes over the course of one day each at Parque Natural Metropolitano (1740 mm annual rainfall) and Parque Nacional San Lorenzo (3300 mm annual rainfall) during the dry season in April, 2016. Using a voxel-based approach, we compared the actual versus potential distance traveled by laser beams through each volume of the canopy. We fit an exponential model to quantify the rate of light extinction. We found that rates of light extinction vary spatially, temporally, and by site. These results indicate that variation in forest structure changes patterns of light attenuation through the canopy over multiple scales.

An Interpolation Method for Obtaining Thermodynamic Properties Near Saturated Liquid and Saturated Vapor Lines

NASA Technical Reports Server (NTRS)

Nguyen, Huy H.; Martin, Michael A.

2004-01-01

The two most common approaches used to formulate thermodynamic properties of pure substances are fundamental (or characteristic) equations of state (Helmholtz and Gibbs functions) and a piecemeal approach that is described in Adebiyi and Russell (1992). This paper neither presents a different method to formulate thermodynamic properties of pure substances nor validates the aforementioned approaches. Rather its purpose is to present a method to generate property tables from existing property packages and a method to facilitate the accurate interpretation of fluid thermodynamic property data from those tables. There are two parts to this paper. The first part of the paper shows how efficient and usable property tables were generated, with the minimum number of data points, using an aerospace industry standard property package. The second part describes an innovative interpolation technique that has been developed to properly obtain thermodynamic properties near the saturated liquid and saturated vapor lines.

Saturated fat (image)

MedlinePlus

... saturated fats. Vegetable sources of saturated fat include coconut and palm oils. When looking at a food ... saturated fats. Vegetable sources of saturated fat include coconut and palm oils. When looking at a food ...

Retinal oxygen saturation evaluation by multi-spectral fundus imaging

NASA Astrophysics Data System (ADS)

Khoobehi, Bahram; Ning, Jinfeng; Puissegur, Elise; Bordeaux, Kimberly; Balasubramanian, Madhusudhanan; Beach, James

2007-03-01

Purpose: To develop a multi-spectral method to measure oxygen saturation of the retina in the human eye. Methods: Five Cynomolgus monkeys with normal eyes were anesthetized with intramuscular ketamine/xylazine and intravenous pentobarbital. Multi-spectral fundus imaging was performed in five monkeys with a commercial fundus camera equipped with a liquid crystal tuned filter in the illumination light path and a 16-bit digital camera. Recording parameters were controlled with software written specifically for the application. Seven images at successively longer oxygen-sensing wavelengths were recorded within 4 seconds. Individual images for each wavelength were captured in less than 100 msec of flash illumination. Slightly misaligned images of separate wavelengths due to slight eye motion were registered and corrected by translational and rotational image registration prior to analysis. Numerical values of relative oxygen saturation of retinal arteries and veins and the underlying tissue in between the artery/vein pairs were evaluated by an algorithm previously described, but which is now corrected for blood volume from averaged pixels (n > 1000). Color saturation maps were constructed by applying the algorithm at each image pixel using a Matlab script. Results: Both the numerical values of relative oxygen saturation and the saturation maps correspond to the physiological condition, that is, in a normal retina, the artery is more saturated than the tissue and the tissue is more saturated than the vein. With the multi-spectral fundus camera and proper registration of the multi-wavelength images, we were able to determine oxygen saturation in the primate retinal structures on a tolerable time scale which is applicable to human subjects. Conclusions: Seven wavelength multi-spectral imagery can be used to measure oxygen saturation in retinal artery, vein, and tissue (microcirculation). This technique is safe and can be used to monitor oxygen uptake in humans. This work

Quantum description of light propagation in generalized media

NASA Astrophysics Data System (ADS)

Häyrynen, Teppo; Oksanen, Jani

2016-02-01

Linear quantum input-output relation based models are widely applied to describe the light propagation in a lossy medium. The details of the interaction and the associated added noise depend on whether the device is configured to operate as an amplifier or an attenuator. Using the traveling wave (TW) approach, we generalize the linear material model to simultaneously account for both the emission and absorption processes and to have point-wise defined noise field statistics and intensity dependent interaction strengths. Thus, our approach describes the quantum input-output relations of linear media with net attenuation, amplification or transparency without pre-selection of the operation point. The TW approach is then applied to investigate materials at thermal equilibrium, inverted materials, the transparency limit where losses are compensated, and the saturating amplifiers. We also apply the approach to investigate media in nonuniform states which can be e.g. consequences of a temperature gradient over the medium or a position dependent inversion of the amplifier. Furthermore, by using the generalized model we investigate devices with intensity dependent interactions and show how an initial thermal field transforms to a field having coherent statistics due to gain saturation.

Oximeter for reliable clinical determination of blood oxygen saturation in a fetus

DOEpatents

Robinson, Mark R.; Haaland, David M.; Ward, Kenneth J.

1996-01-01

With the crude instrumentation now in use to continuously monitor the status of the fetus at delivery, the obstetrician and labor room staff not only over-recognize the possibility of fetal distress with the resultant rise in operative deliveries, but at times do not identify fetal distress which may result in preventable fetal neurological harm. The invention, which addresses these two basic problems, comprises a method and apparatus for non-invasive determination of blood oxygen saturation in the fetus. The apparatus includes a multiple frequency light source which is coupled to an optical fiber. The output of the fiber is used to illuminate blood containing tissue of the fetus. In the preferred embodiment, the reflected light is transmitted back to the apparatus where the light intensities are simultaneously detected at multiple frequencies. The resulting spectrum is then analyzed for determination of oxygen saturation. The analysis method uses multivariate calibration techniques that compensate for nonlinear spectral response, model interfering spectral responses and detect outlier data with high sensitivity.

[Response processes of Aralia elata photosynthesis and transpiration to light and soil moisture].

PubMed

Chen, Jian; Zhang, Guang-Can; Zhang, Shu-Yong; Wang, Meng-Jun

2008-06-01

By using CIRAS-2 portable photosynthesis system, the light response processes of Aralia elata photosynthesis and transpiration under different soil moisture conditions were studied, aimed to understand the adaptability of A. elata to different light and soil moisture conditions. The results showed that the response processes of A. elata net photosynthetic rate (Pn), transpiration rate (Tr), and water use efficiency (WUE) to photon flux density (PFD) were different. With the increasing PFD in the range of 800-1800 micromol x m2(-2) x s(-1), Pn changed less, Tr decreased gradually, while WUE increased obviously. The light saturation point (LSP) and light compensation point (LCP) were about 800 and 30 micromol m(-2) x s(-1), respectively, and less affected by soil water content; while the apparent photosynthetic quantum yield (Phi) and dark respiratory rate (Rd) were more affected by the moisture content. The Pn and WUE had evident threshold responses to the variations of soil water content. When the soil relative water content (RWC) was in the range of 44%-79%, A. elata could have higher levels of Pn and WUE.

PSFGAN: a generative adversarial network system for separating quasar point sources and host galaxy light

NASA Astrophysics Data System (ADS)

Stark, Dominic; Launet, Barthelemy; Schawinski, Kevin; Zhang, Ce; Koss, Michael; Turp, M. Dennis; Sartori, Lia F.; Zhang, Hantian; Chen, Yiru; Weigel, Anna K.

2018-06-01

The study of unobscured active galactic nuclei (AGN) and quasars depends on the reliable decomposition of the light from the AGN point source and the extended host galaxy light. The problem is typically approached using parametric fitting routines using separate models for the host galaxy and the point spread function (PSF). We present a new approach using a Generative Adversarial Network (GAN) trained on galaxy images. We test the method using Sloan Digital Sky Survey r-band images with artificial AGN point sources added that are then removed using the GAN and with parametric methods using GALFIT. When the AGN point source is more than twice as bright as the host galaxy, we find that our method, PSFGAN, can recover point source and host galaxy magnitudes with smaller systematic error and a lower average scatter (49 per cent). PSFGAN is more tolerant to poor knowledge of the PSF than parametric methods. Our tests show that PSFGAN is robust against a broadening in the PSF width of ± 50 per cent if it is trained on multiple PSFs. We demonstrate that while a matched training set does improve performance, we can still subtract point sources using a PSFGAN trained on non-astronomical images. While initial training is computationally expensive, evaluating PSFGAN on data is more than 40 times faster than GALFIT fitting two components. Finally, PSFGAN is more robust and easy to use than parametric methods as it requires no input parameters.

Multi-spectral imaging of oxygen saturation

NASA Astrophysics Data System (ADS)

Savelieva, Tatiana A.; Stratonnikov, Aleksander A.; Loschenov, Victor B.

2008-06-01

The system of multi-spectral imaging of oxygen saturation is an instrument that can record both spectral and spatial information about a sample. In this project, the spectral imaging technique is used for monitoring of oxygen saturation of hemoglobin in human tissues. This system can be used for monitoring spatial distribution of oxygen saturation in photodynamic therapy, surgery or sports medicine. Diffuse reflectance spectroscopy in the visible range is an effective and extensively used technique for the non-invasive study and characterization of various biological tissues. In this article, a short review of modeling techniques being currently in use for diffuse reflection from semi-infinite turbid media is presented. A simple and practical model for use with a real-time imaging system is proposed. This model is based on linear approximation of the dependence of the diffuse reflectance coefficient on relation between absorbance and reduced scattering coefficient. This dependence was obtained with the Monte Carlo simulation of photon propagation in turbid media. Spectra of the oxygenated and deoxygenated forms of hemoglobin differ mostly in the red area (520 - 600 nm) and have several characteristic points there. Thus four band-pass filters were used for multi-spectral imaging. After having measured the reflectance, the data obtained are used for fitting the concentration of oxygenated and free hemoglobin, and hemoglobin oxygen saturation.

76 FR 26771 - Florida Power & Light Company; Turkey Point, Units 3 and 4; Notice of Consideration of Issuance...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-09

... Company; Turkey Point, Units 3 and 4; Notice of Consideration of Issuance of Amendment to Facility... issued to Florida Power & Light Co. (the licensee) for operation of the Turkey Point Nuclear Generating... licensed core power level for Turkey Point, Units 3 and 4, from 2300 megawatts thermal (MWt) to 2644 MWt...

Light-induced vegetative anthocyanin pigmentation in Petunia

PubMed Central

Albert, Nick W.; Lewis, David H.; Zhang, Huaibi; Irving, Louis J.; Jameson, Paula E.; Davies, Kevin M.

2009-01-01

The Lc petunia system, which displays enhanced, light-induced vegetative pigmentation, was used to investigate how high light affects anthocyanin biosynthesis, and to assess the effects of anthocyanin pigmentation upon photosynthesis. Lc petunia plants displayed intense purple anthocyanin pigmentation throughout the leaves and stems when grown under high-light conditions, yet remain acyanic when grown under shade conditions. The coloured phenotypes matched with an accumulation of anthocyanins and flavonols, as well as the activation of the early and late flavonoid biosynthetic genes required for flavonol and anthocyanin production. Pigmentation in Lc petunia only occurred under conditions which normally induce a modest amount of anthocyanin to accumulate in wild-type Mitchell petunia [Petunia axillaris×(Petunia axillaris×Petunia hybrida cv. ‘Rose of Heaven’)]. Anthocyanin pigmentation in Lc petunia leaves appears to screen underlying photosynthetic tissues, increasing light saturation and light compensation points, without reducing the maximal photosynthetic assimilation rate (Amax). In the Lc petunia system, where the bHLH factor Leaf colour is constitutively expressed, expression of the bHLH (Lc) and WD40 (An11) components of the anthocyanin regulatory system were not limited, suggesting that the high-light-induced anthocyanin pigmentation is regulated by endogenous MYB transcription factors. PMID:19380423

Solar Panel System for Street Light Using Maximum Power Point Tracking (MPPT) Technique

NASA Astrophysics Data System (ADS)

Wiedjaja, A.; Harta, S.; Josses, L.; Winardi; Rinda, H.

2014-03-01

Solar energy is one form of the renewable energy which is very abundant in regions close to the equator. One application of solar energy is for street light. This research focuses on using the maximum power point tracking technique (MPPT), particularly the perturb and observe (P&O) algorithm, to charge battery for street light system. The proposed charger circuit can achieve 20.73% higher power efficiency compared to that of non-MPPT charger. We also develop the LED driver circuit for the system which can achieve power efficiency up to 91.9% at a current of 1.06 A. The proposed street lightning system can be implemented with a relatively low cost for public areas.

Multistability of second-order competitive neural networks with nondecreasing saturated activation functions.

PubMed

Nie, Xiaobing; Cao, Jinde

2011-11-01

In this paper, second-order interactions are introduced into competitive neural networks (NNs) and the multistability is discussed for second-order competitive NNs (SOCNNs) with nondecreasing saturated activation functions. Firstly, based on decomposition of state space, Cauchy convergence principle, and inequality technique, some sufficient conditions ensuring the local exponential stability of 2N equilibrium points are derived. Secondly, some conditions are obtained for ascertaining equilibrium points to be locally exponentially stable and to be located in any designated region. Thirdly, the theory is extended to more general saturated activation functions with 2r corner points and a sufficient criterion is given under which the SOCNNs can have (r+1)N locally exponentially stable equilibrium points. Even if there is no second-order interactions, the obtained results are less restrictive than those in some recent works. Finally, three examples with their simulations are presented to verify the theoretical analysis.

Bulk hydrodynamic stability and turbulent saturation in compressing hot spots

NASA Astrophysics Data System (ADS)

Davidovits, Seth; Fisch, Nathaniel J.

2018-04-01

For hot spots compressed at constant velocity, we give a hydrodynamic stability criterion that describes the expected energy behavior of non-radial hydrodynamic motion for different classes of trajectories (in ρR — T space). For a given compression velocity, this criterion depends on ρR, T, and d T /d (ρR ) (the trajectory slope) and applies point-wise so that the expected behavior can be determined instantaneously along the trajectory. Among the classes of trajectories are those where the hydromotion is guaranteed to decrease and those where the hydromotion is bounded by a saturated value. We calculate this saturated value and find the compression velocities for which hydromotion may be a substantial fraction of hot-spot energy at burn time. The Lindl (Phys. Plasmas 2, 3933 (1995)] "attractor" trajectory is shown to experience non-radial hydrodynamic energy that grows towards this saturated state. Comparing the saturation value with the available detailed 3D simulation results, we find that the fluctuating velocities in these simulations reach substantial fractions of the saturated value.

Consideration of velocity saturation in the design of GaAs varactor diodes

NASA Technical Reports Server (NTRS)

Crowe, Thomas W.; Peatman, William C. B.; Zimmermann, Ruediger; Zimmermann, Ralph

1993-01-01

The design of GaAs Schottky barrier varactor diodes is reconsidered in light of the recent discovery of velocity saturation effects in these devices. Experimental data is presented which confirms that improved multiplier performance can be achieved.

[Effects of light intensity on growth and photosynthetic characteristics of Tulipa edulis].

PubMed

Xu, Hongjian; Zhu, Zaibiao; Guo, Qiaosheng; Wu, Zhengjun; Ma, Hongliang; Miao, Yuanyuan

2012-02-01

Present study was conducted to explore the growth and photosynthetic characteristics of Tulipa edulis under different light conditions (23%, 45%, 63%, 78%, 100% of full sunlight) and to determine the optimum light intensity for growth of T. edulis. The leaf area and biomass indicators as well as reproductive characteristics were measured. The photosynthetic basic parameters and light response curve were determined by a LI-6400XT portable photosynthesis system, and the light response curve characteristic parameters was determined. Additionally, chlorophyll fluorescence parameters were determined by assorted fluorescence leaf chamber of LI-6400XT. The lowest biomass yield was observed in the 23% and 100% of full sunlight treatments while the highest value was found under the 78% of full sunlight conditions. With the reduction of light availability, the success rate of sexual reproduction, light saturation point (LSP) and light compensation point (LCP) reduced, while apparent quantum yield (AQY) increased. 23% and 45% of full sunlight treatments led to lower photosynthesis rate (Pn) and higher apparent quantum yield (AQY) in comparison with other treatents. The highest photosynthesis rate was observed in the 78% and 100% of full sunlight treatments. In addition, 78% of full sunlight treatments led to highest Fv/Fm, Fv'/Fm', PhiPS II, ETR, and qP. T. edulis was able to adapt in a wide range of light intensity, and 78% of full sunlinght was the most suitable light condition for growth of T. edulis.

Effect of laser cavity parameters on saturation of light – current characteristics of high-power pulsed lasers

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

Veselov, D A; Pikhtin, N A; Lyutetskiy, A V

2015-07-31

We report an experimental study of power characteristics of semiconductor lasers based on MOVPE-grown asymmetric separate-confinement heterostructures with a broadened waveguide as functions of cavity length, stripe contact width and mirror reflectivities. It is shown that at high current pump levels, the variation of the cavity parameters of a semiconductor laser (width, length and mirror reflectivities) influences the light – current (L – I) characteristic saturation and maximum optical power by affecting such laser characteristics, as the current density and the optical output loss. A model is elaborated and an optical power of semiconductor lasers is calculated by taking intomore » account the dependence of the internal optical loss on pump current density and concentration distribution of charge carriers and photons along the cavity axis of the cavity. It is found that only introduction of the dependence of the internal optical loss on pump current density to the calculation model provides a good agreement between experimental and calculated L – I characteristics for all scenarios of variations in the laser cavity parameters. (lasers)« less

Pulse oximetry in the pulmonary tissue for the non-invasive measurement of mixed venous oxygen saturation.

PubMed

Nitzan, Meir; Nitzan, Itamar

2013-08-01

The oxygen saturation of the systemic arterial blood is associated with the adequacy of respiration, and can be measured non-invasively by pulse oximetry in the systemic tissue. The oxygen saturation of the blood in the pulmonary artery, the mixed venous blood, reflects the balance between oxygen supply to the systemic tissues and their oxygen demand. The mixed venous oxygen saturation has also clinical significance because it is used in Fick equation for the quantitative measurement of cardiac output. At present the measurement of the mixed venous oxygen saturation is invasive and requires insertion of a Swan-Ganz catheter into the pulmonary artery. We suggest a noninvasive method for the measurement of the mixed venous oxygen saturation in infants, pulmonary pulse oximetry. The method is similar to the systemic pulse oximetry, which is based on the different light absorption curves of oxygenated and deoxygenated hemoglobin and on the analysis of photoplethysmographic curves in two wavelengths. The proposed pulmonary pulse oximeter includes light-sources of two wavelengths in the infrared, which illuminate the pulmonary tissue through the thoracic wall. Part of the light which is scattered back from the pulmonary tissue and passes through the thoracic wall is detected, and for each wavelength a pulmonary photoplethysmographic curve is obtained. The pulmonary photoplethysmographic curves reflect blood volume increase during systole in the pulmonary arteries in the lung tissue, which contain mixed venous blood. The ratio R of the amplitude-to-baseline ratio for the two wavelengths is related to the mixed venous oxygen saturation through equations derived for the systemic pulse oximetry. The method requires the use of extinction coefficients values for oxygenated and deoxygenated hemoglobin, which can be found in the literature. Copyright © 2013 Elsevier Ltd. All rights reserved.

The resolution of point sources of light as analyzed by quantum detection theory

NASA Technical Reports Server (NTRS)

Helstrom, C. W.

1972-01-01

The resolvability of point sources of incoherent light is analyzed by quantum detection theory in terms of two hypothesis-testing problems. In the first, the observer must decide whether there are two sources of equal radiant power at given locations, or whether there is only one source of twice the power located midway between them. In the second problem, either one, but not both, of two point sources is radiating, and the observer must decide which it is. The decisions are based on optimum processing of the electromagnetic field at the aperture of an optical instrument. In both problems the density operators of the field under the two hypotheses do not commute. The error probabilities, determined as functions of the separation of the points and the mean number of received photons, characterize the ultimate resolvability of the sources.

A reflectance model for non-contact mapping of venous oxygen saturation using a CCD camera

NASA Astrophysics Data System (ADS)

Li, Jun; Dunmire, Barbrina; Beach, Kirk W.; Leotta, Daniel F.

2013-11-01

A method of non-contact mapping of venous oxygen saturation (SvO2) is presented. A CCD camera is used to image skin tissue illuminated alternately by a red (660 nm) and an infrared (800 nm) LED light source. Low cuff pressures of 30-40 mmHg are applied to induce a venous blood volume change with negligible change in the arterial blood volume. A hybrid model combining the Beer-Lambert law and the light diffusion model is developed and used to convert the change in the light intensity to the change in skin tissue absorption coefficient. A simulation study incorporating the full light diffusion model is used to verify the hybrid model and to correct a calculation bias. SvO2 in the fingers, palm, and forearm for five volunteers are presented and compared with results in the published literature. Two-dimensional maps of venous oxygen saturation are given for the three anatomical regions.

In Situ Observation of Modulated Light Emission of Fiber Fuse Synchronized with Void Train over Hetero-Core Splice Point

PubMed Central

Todoroki, Shin-ichi

2008-01-01

Background Fiber fuse is a process of optical fiber destruction under the action of laser radiation, found 20 years ago. Once initiated, opical discharge runs along the fiber core region to the light source and leaves periodic voids whose shape looks like a bullet pointing the direction of laser beam. The relation between damage pattern and propagation mode of optical discharge is still unclear even after the first in situ observation three years ago. Methodology/Principal Findings Fiber fuse propagation over hetero-core splice point (Corning SMF-28e and HI 1060) was observed in situ. Sequential photographs obtained at intervals of 2.78 µs recorded a periodic emission at the tail of an optical discharge pumped by 1070 nm and 9 W light. The signal stopped when the discharge ran over the splice point. The corresponding damage pattern left in the fiber core region included a segment free of periodicity. Conclusions The spatial modulation pattern of the light emission agreed with the void train formed over the hetero-core splice point. Some segments included a bullet-shaped void pointing in the opposite direction to the laser beam propagation although the sequential photographs did not reveal any directional change in the optical discharge propagation. PMID:18815621

Polariton condensation with saturable molecules dressed by vibrational modes

DOE PAGES

Cwik, Justyna A.; Reja, Sahinur; Littlewood, Peter B.; ...

2014-02-01

Here, polaritons, mixed light-matter quasiparticles, undergo a transition to a condensed, macroscopically coherent state at low temperatures or high densities. Recent experiments show that coupling light to organic molecules inside a microcavity allows condensation at room temperature. The molecules act as saturable absorbers with transitions dressed by molecular vibrational modes. Motivated by this, we calculate the phase diagram and spectrum of a modified Tavis-Cummings model, describing vibrationally dressed two-level systems, coupled to a cavity mode. Coupling to vibrational modes can induce re-entrance, i.e. a normal-condensed-normal sequence with decreasing temperature and can drive the transition first-order.

Design, fabrication and delivery of a prototype saturator for ACPL

NASA Technical Reports Server (NTRS)

Keyser, G.; Rogers, C. F.; Squires, P.

1979-01-01

The design configuration and performance characteristics of a saturator developed to provide ground-based simulation for some of the experiments for ACPL-1 first flights of Spacelab are described, some difficulties encountered with the apparatus are discussed, and recommendations concerning testing of this type of instrument are presented. The saturators provide a means of accurately fixing the water vapor mixing ratio of an aerosol sample. Dew point temperatures from almost freezing to ambient room temperatures can be attained with high precision. The instruments can accommodate aerosol flow rates approaching 1000 cc/s. Provisions were made to inject aerosols upstream of these saturators, although downstream injection can be accomplished as well. A device of this type will be used in the ACPL-1 to condition various aerosols delivered concurrently to a CFD, expansion chamber, and static diffusion chamber used in zero gravity cloud-forming experiments. The saturator was designed to meet the requirements projected for the flight instrument.

Simulation of oxygen saturation measurement in a single blood vein.

PubMed

Duadi, Hamootal; Nitzan, Meir; Fixler, Dror

2016-09-15

The value of oxygen saturation in venous blood, SvO₂, has important clinical significance since it is related to the tissue oxygen utilization, which is related to the blood flow to the tissue and to its metabolism rate. However, existing pulse oximetry techniques are not suitable for blood in veins. In the current study we examine the feasibility of difference oximetry to assess SvO₂ by using two near-infrared wavelengths and collecting the backscattered light from two photodetectors located at different distances from the light source.

Nonlinear Saturable and Polarization-induced Absorption of Rhenium Disulfide

PubMed Central

Cui, Yudong; Lu, Feifei; Liu, Xueming

2017-01-01

Monolayer of transition metal dichalcogenides (TMDs), with lamellar structure as that of graphene, has attracted significant attentions in optoelectronics and photonics. Here, we focus on the optical absorption response of a new member TMDs, rhenium disulphide (ReS2) whose monolayer and bulk forms have the nearly identical band structures. The nonlinear saturable and polarization-induced absorption of ReS2 are investigated at near-infrared communication band beyond its bandgap. It is found that the ReS2-covered D-shaped fiber (RDF) displays the remarkable polarization-induced absorption, which indicates the different responses for transverse electric (TE) and transverse magnetic (TM) polarizations relative to ReS2 plane. Nonlinear saturable absorption of RDF exhibits the similar saturable fluence of several tens of μJ/cm2 and modulation depth of about 1% for ultrafast pulses with two orthogonal polarizations. RDF is utilized as a saturable absorber to achieve self-started mode-locking operation in an Er-doped fiber laser. The results broaden the operation wavelength of ReS2 from visible light to around 1550 nm, and numerous applications may benefit from the anisotropic and nonlinear absorption characteristics of ReS2, such as in-line optical polarizers, high-power pulsed lasers, and optical communication system. PMID:28053313

46 CFR 7.125 - Point Vincente, CA to Point Conception, CA.

Code of Federal Regulations, 2010 CFR

2010-10-01

... BOUNDARY LINES Pacific Coast § 7.125 Point Vincente, CA to Point Conception, CA. (a) A line drawn from Redondo Beach East Jetty Light “2” to Redondo Beach West Jetty Light “3”. (b) A line drawn from Marina Del... 46 Shipping 1 2010-10-01 2010-10-01 false Point Vincente, CA to Point Conception, CA. 7.125...

46 CFR 7.125 - Point Vincente, CA to Point Conception, CA.

Code of Federal Regulations, 2012 CFR

2012-10-01

... BOUNDARY LINES Pacific Coast § 7.125 Point Vincente, CA to Point Conception, CA. (a) A line drawn from Redondo Beach East Jetty Light “2” to Redondo Beach West Jetty Light “3”. (b) A line drawn from Marina Del... 46 Shipping 1 2012-10-01 2012-10-01 false Point Vincente, CA to Point Conception, CA. 7.125...

46 CFR 7.125 - Point Vincente, CA to Point Conception, CA.

Code of Federal Regulations, 2013 CFR

2013-10-01

... BOUNDARY LINES Pacific Coast § 7.125 Point Vincente, CA to Point Conception, CA. (a) A line drawn from Redondo Beach East Jetty Light “2” to Redondo Beach West Jetty Light “3”. (b) A line drawn from Marina Del... 46 Shipping 1 2013-10-01 2013-10-01 false Point Vincente, CA to Point Conception, CA. 7.125...

46 CFR 7.125 - Point Vincente, CA to Point Conception, CA.

Code of Federal Regulations, 2014 CFR

2014-10-01

... BOUNDARY LINES Pacific Coast § 7.125 Point Vincente, CA to Point Conception, CA. (a) A line drawn from Redondo Beach East Jetty Light “2” to Redondo Beach West Jetty Light “3”. (b) A line drawn from Marina Del... 46 Shipping 1 2014-10-01 2014-10-01 false Point Vincente, CA to Point Conception, CA. 7.125...

46 CFR 7.125 - Point Vincente, CA to Point Conception, CA.

Code of Federal Regulations, 2011 CFR

2011-10-01

... BOUNDARY LINES Pacific Coast § 7.125 Point Vincente, CA to Point Conception, CA. (a) A line drawn from Redondo Beach East Jetty Light “2” to Redondo Beach West Jetty Light “3”. (b) A line drawn from Marina Del... 46 Shipping 1 2011-10-01 2011-10-01 false Point Vincente, CA to Point Conception, CA. 7.125...

Photosynthetic Light Responses May Explain Vertical Distribution of Hymenophyllaceae Species in a Temperate Rainforest of Southern Chile.

PubMed

Parra, María José; Acuña, Karina I; Sierra-Almeida, Angela; Sanfuentes, Camila; Saldaña, Alfredo; Corcuera, Luis J; Bravo, León A

2015-01-01

Some epiphytic Hymenophyllaceae are restricted to lower parts of the host (< 60 cm; 10-100 μmol photons m(-2) s(-1)) in a secondary forest of Southern Chile; other species occupy the whole host height (≥ 10 m; max PPFD > 1000 μmol photons m(-2) s(-1)). Our aim was to study the photosynthetic light responses of two Hymenophyllaceae species in relation to their contrasting distribution. We determined light tolerance of Hymenoglossum cruentum and Hymenophyllum dentatum by measuring gas exchange, PSI and PSII light energy partitioning, NPQ components, and pigment contents. H. dentatum showed lower maximum photosynthesis rates (A max) than H. cruentum, but the former species kept its net rates (An) near Amax across a wide light range. In contrast, in the latter one, An declined at PPFDs > 60 μmol photons m(-2) s(-1). H. cruentum, the shadiest plant, showed higher chlorophyll contents than H. dentatum. Differences in energy partitioning at PSI and PSII were consistent with gas exchange results. H. dentatum exhibited a higher light compensation point of the partitioning of absorbed energy between photochemical Y(PSII) and non-photochemical Y(NPQ) processes. Hence, both species allocated energy mainly toward photochemistry instead of heat dissipation at their light saturation points. Above saturation, H. cruentum had higher heat dissipation than H. dentatum. PSI yield (YPSI) remained higher in H. dentatum than H. cruentum in a wider light range. In both species, the main cause of heat dissipation at PSI was a donor side limitation. An early dynamic photo-inhibition of PSII may have caused an over reduction of the Qa+ pool decreasing the efficiency of electron donation to PSI. In H. dentatum, a slight increase in heat dissipation due to acceptor side limitation of PSI was observed above 300 μmol photons m(-2)s(-1). Differences in photosynthetic responses to light suggest that light tolerance and species plasticity could explain their contrasting vertical distribution.

Contrast-dependent saturation adjustment for outdoor image enhancement.

PubMed

Wang, Shuhang; Cho, Woon; Jang, Jinbeum; Abidi, Mongi A; Paik, Joonki

2017-01-01

Outdoor images captured in bad-weather conditions usually have poor intensity contrast and color saturation since the light arriving at the camera is severely scattered or attenuated. The task of improving image quality in poor conditions remains a challenge. Existing methods of image quality improvement are usually effective for a small group of images but often fail to produce satisfactory results for a broader variety of images. In this paper, we propose an image enhancement method, which makes it applicable to enhance outdoor images by using content-adaptive contrast improvement as well as contrast-dependent saturation adjustment. The main contribution of this work is twofold: (1) we propose the content-adaptive histogram equalization based on the human visual system to improve the intensity contrast; and (2) we introduce a simple yet effective prior for adjusting the color saturation depending on the intensity contrast. The proposed method is tested with different kinds of images, compared with eight state-of-the-art methods: four enhancement methods and four haze removal methods. Experimental results show the proposed method can more effectively improve the visibility and preserve the naturalness of the images, as opposed to the compared methods.

Spatial and spectral imaging of point-spread functions using a spatial light modulator

NASA Astrophysics Data System (ADS)

Munagavalasa, Sravan; Schroeder, Bryce; Hua, Xuanwen; Jia, Shu

2017-12-01

We develop a point-spread function (PSF) engineering approach to imaging the spatial and spectral information of molecular emissions using a spatial light modulator (SLM). We show that a dispersive grating pattern imposed upon the emission reveals spectral information. We also propose a deconvolution model that allows the decoupling of the spectral and 3D spatial information in engineered PSFs. The work is readily applicable to single-molecule measurements and fluorescent microscopy.

Cerebral oxygen saturation and cardiac output during anaesthesia in sitting position for neurosurgical procedures: a prospective observational study.

PubMed

Schramm, P; Tzanova, I; Hagen, F; Berres, M; Closhen, D; Pestel, G; Engelhard, K

2016-10-01

Neurosurgical operations in the dorsal cranium often require the patient to be positioned in a sitting position. This can be associated with decreased cardiac output and cerebral hypoperfusion, and possibly, inadequate cerebral oxygenation. In the present study, cerebral oxygen saturation was measured during neurosurgery in the sitting position and correlated with cardiac output. Perioperative cerebral oxygen saturation was measured continuously with two different monitors, INVOS ® and FORE-SIGHT ® . Cardiac output was measured at eight predefined time points using transoesophageal echocardiography. Forty patients were enrolled, but only 35 (20 female) were eventually operated on in the sitting position. At the first time point, the regional cerebral oxygen saturation measured with INVOS ® was 70 (sd 9)%; thereafter, it increased by 0.0187% min -1 (P<0.01). The cerebral tissue oxygen saturation measured with FORE-SIGHT ® started at 68 (sd 13)% and increased by 0.0142% min -1 (P<0.01). The mean arterial blood pressure did not change. Cardiac output was between 6.3 (sd 1.3) and 7.2 (1.8) litre min -1 at the predefined time points. Cardiac output, but not mean arterial blood pressure, showed a positive and significant correlation with cerebral oxygen saturation. During neurosurgery in the sitting position, the cerebral oxygen saturation slowly increases and, therefore, this position seems to be safe with regard to cerebral oxygen saturation. Cerebral oxygen saturation is stable because of constant CO and MAP, while the influence of CO on cerebral oxygen saturation seems to be more relevant. NCT01275898. © The Author 2016. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Large-Velocity Saturation in Thin-Film Black Phosphorus Transistors.

PubMed

Chen, Xiaolong; Chen, Chen; Levi, Adi; Houben, Lothar; Deng, Bingchen; Yuan, Shaofan; Ma, Chao; Watanabe, Kenji; Taniguchi, Takashi; Naveh, Doron; Du, Xu; Xia, Fengnian

2018-05-22

A high saturation velocity semiconductor is appealing for applications in electronics and optoelectronics. Thin-film black phosphorus (BP), an emerging layered semiconductor, shows a high carrier mobility and strong mid-infrared photoresponse at room temperature. Here, we report the observation of high intrinsic saturation velocity in 7 to 11 nm thick BP for both electrons and holes as a function of charge-carrier density, temperature, and crystalline direction. We distinguish a drift velocity transition point due to the competition between the electron-impurity and electron-phonon scatterings. We further achieve a room-temperature saturation velocity of 1.2 (1.0) × 10 7 cm s -1 for hole (electron) carriers at a critical electric field of 14 (13) kV cm -1 , indicating an intrinsic current-gain cutoff frequency ∼20 GHz·μm for radio frequency applications. Moreover, the current density is as high as 580 μA μm -1 at a low electric field of 10 kV cm -1 . Our studies demonstrate that thin-film BP outperforms silicon in terms of saturation velocity and critical field, revealing its great potential in radio-frequency electronics, high-speed mid-infrared photodetectors, and optical modulators.

Lipase-catalyzed transesterification to remove saturated monoacylglycerols from biodiesel

USDA-ARS?s Scientific Manuscript database

Saturated monoacylglycerols (SMG) are known to be present in fatty acid methyl esters (FAME) intended to be used as biodiesel. These SMG can strongly affect the properties of biofuels such as the cloud point, and they have been implicated in engine failure due to filter plugging. It is shown here th...

Saturated virtual fluorescence emission difference microscopy based on detector array

NASA Astrophysics Data System (ADS)

Liu, Shaocong; Sun, Shiyi; Kuang, Cuifang; Ge, Baoliang; Wang, Wensheng; Liu, Xu

2017-07-01

Virtual fluorescence emission difference microscopy (vFED) has been proposed recently to enhance the lateral resolution of confocal microscopy with a detector array, implemented by scanning a doughnut-shaped pattern. Theoretically, the resolution can be enhanced by around 1.3-fold compared with that in confocal microscopy. For further improvement of the resolving ability of vFED, a novel method is presented utilizing fluorescence saturation for super-resolution imaging, which we called saturated virtual fluorescence emission difference microscopy (svFED). With a point detector array, matched solid and hollow point spread functions (PSF) can be obtained by photon reassignment, and the difference results between them can be used to boost the transverse resolution. Results show that the diffraction barrier can be surpassed by at least 34% compared with that in vFED and the resolution is around 2-fold higher than that in confocal microscopy.

The signer and the sign: cortical correlates of person identity and language processing from point-light displays.

PubMed

Campbell, Ruth; Capek, Cheryl M; Gazarian, Karine; MacSweeney, Mairéad; Woll, Bencie; David, Anthony S; McGuire, Philip K; Brammer, Michael J

2011-09-01

In this study, the first to explore the cortical correlates of signed language (SL) processing under point-light display conditions, the observer identified either a signer or a lexical sign from a display in which different signers were seen producing a number of different individual signs. Many of the regions activated by point-light under these conditions replicated those previously reported for full-image displays, including regions within the inferior temporal cortex that are specialised for face and body-part identification, although such body parts were invisible in the display. Right frontal regions were also recruited - a pattern not usually seen in full-image SL processing. This activation may reflect the recruitment of information about person identity from the reduced display. A direct comparison of identify-signer and identify-sign conditions showed these tasks relied to a different extent on the posterior inferior regions. Signer identification elicited greater activation than sign identification in (bilateral) inferior temporal gyri (BA 37/19), fusiform gyri (BA 37), middle and posterior portions of the middle temporal gyri (BAs 37 and 19), and superior temporal gyri (BA 22 and 42). Right inferior frontal cortex was a further focus of differential activation (signer>sign). These findings suggest that the neural systems supporting point-light displays for the processing of SL rely on a cortical network including areas of the inferior temporal cortex specialized for face and body identification. While this might be predicted from other studies of whole body point-light actions (Vaina, Solomon, Chowdhury, Sinha, & Belliveau, 2001) it is not predicted from the perspective of spoken language processing, where voice characteristics and speech content recruit distinct cortical regions (Stevens, 2004) in addition to a common network. In this respect, our findings contrast with studies of voice/speech recognition (Von Kriegstein, Kleinschmidt, Sterzer

Light Increases Energy Transfer Efficiency in a Boreal Stream

PubMed Central

Lesutienė, Jūratė; Gorokhova, Elena; Stankevičienė, Daiva; Bergman, Eva; Greenberg, Larry

2014-01-01

Periphyton communities of a boreal stream were exposed to different light and nutrient levels to estimate energy transfer efficiency from primary to secondary producers using labeling with inorganic 13C. In a one-day field experiment, periphyton grown in fast-flow conditions and dominated by opportunistic green algae were exposed to light levels corresponding to sub-saturating (forest shade) and saturating (open stream section) irradiances, and to N and P nutrient additions. In a two-week laboratory experiment, periphyton grown in low-flow conditions and dominated by slowly growing diatoms were incubated under two sub-saturating light and nutrient enrichment levels as well as grazed and non-grazed conditions. Light had significant positive effect on 13C uptake by periphyton. In the field experiment, P addition had a positive effect on 13C uptake but only at sub-saturating light levels, whereas in the laboratory experiment nutrient additions had no effect on the periphyton biomass, 13C uptake, biovolume and community composition. In the laboratory experiment, the grazer (caddisfly) effect on periphyton biomass specific 13C uptake and nutrient content was much stronger than the effects of light and nutrients. In particular, grazers significantly reduced periphyton biomass and increased biomass specific 13C uptake and C:nutrient ratios. The energy transfer efficiency, estimated as a ratio between 13C uptake by caddisfly and periphyton, was positively affected by light conditions, whereas the nutrient effect was not significant. We suggest that the observed effects on energy transfer were related to the increased diet contribution of highly palatable green algae, stimulated by higher light levels. Also, high heterotrophic microbial activity under low light levels would facilitate energy loss through respiration and decrease overall trophic transfer efficiency. These findings suggest that even a small increase in light intensity could result in community-wide effects on

An Interpolation Method for Obtaining Thermodynamic Properties Near Saturated Liquid and Saturated Vapor Lines

NASA Technical Reports Server (NTRS)

Nguyen, Huy H.; Martin, Michael A.

2003-01-01

The availability and proper utilization of fluid properties is of fundamental importance in the process of mathematical modeling of propulsion systems. Real fluid properties provide the bridge between the realm of pure analytiis and empirical reality. The two most common approaches used to formulate thermodynamic properties of pure substances are fundamental (or characteristic) equations of state (Helmholtz and Gibbs functions) and a piecemeal approach that is described, for example, in Adebiyi and Russell (1992). This paper neither presents a different method to formulate thermodynamic properties of pure substances nor validates the aforementioned approaches. Rather its purpose is to present a method to be used to facilitate the accurate interpretation of fluid thermodynamic property data generated by existing property packages. There are two parts to this paper. The first part of the paper shows how efficient and usable property tables were generated, with the minimum number of data points, using an aerospace industry standard property package (based on fundamental equations of state approach). The second part describes an innovative interpolation technique that has been developed to properly obtain thermodynamic properties near the saturated liquid and saturated vapor lines.

Influence of the chopped frequency of light on optical transport characteristics of human skin including at acupuncture points

NASA Astrophysics Data System (ADS)

Yang, Hong-qin; Xie, Shu-sen; Liu, Song-hao; Li, Hui; Wang, Yu-hua; Guo, Zhou-yi

2007-11-01

An experimental protocol was established for noninvasively measuring the optical transport characteristics of skin tissue along human meridian direction over body surface including at acupuncture points. The diffuse remittance for 658 nm light radiation along the pericardium meridian and non-meridian directions were measured respectively. The influence of the chopped frequency of light on the detected light signal was investigated. It is shown that the optical transport characteristics of skin tissue accords with the Beer's exponential attenuation law along the meridian including at acupuncture points and non-median directions. However there is an obvious difference between the propagations along the meridian direction and non-meridian direction (P<0.05). Furthermore, the chopped frequency can affect the detected signal. The diffuse remittance signal decreased with the chopped frequency's increase and it was different between the meridian and non-meridian directions. These findings are important and meaningful for interpreting the human meridian phenomena by biomedical optics.

Phenomenological model and phase behavior of saturated and unsaturated lipids and cholesterol.

PubMed

Putzel, G Garbès; Schick, M

2008-11-15

We present a phenomenological theory for the phase behavior of ternary mixtures of cholesterol and saturated and unsaturated lipids, one that describes both liquid and gel phases. It leads to the following description of the mechanism of the phase behavior: In a binary system of the lipids, phase separation occurs when the saturated chains are well ordered, as in the gel phase, simply due to packing effects. In the liquid phase, the saturated ones are not sufficiently well ordered for separation to occur. The addition of cholesterol, however, increases the saturated lipid order to the point that phase separation is once again favorable. Our theory addresses this last mechanism-the means by which cholesterol-mediated ordering of membrane lipids leads to liquid-liquid immiscibility. It produces, for the system above the main chain transition of the saturated lipid, phase diagrams in which there can be liquid-liquid phase separation in the ternary system but not in any of the binary ones, while below that temperature it yields the more common phase diagram in which a gel phase, rich in saturated lipid, appears in addition to the two liquid phases.

Microscopic analysis of saturable absorbers: Semiconductor saturable absorber mirrors versus graphene

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

Hader, J.; Moloney, J. V.; College of Optical Sciences, University of Arizona, Tucson, Arizona 85721

2016-02-07

Fully microscopic many-body calculations are used to study the influence of strong sub-picosecond pulses on the carrier distributions and corresponding optical response in saturable absorbers used for mode-locking—semiconductor (quantum well) saturable absorber mirrors (SESAMs) and single layer graphene based saturable absorber mirrors (GSAMs). Unlike in GSAMs, the saturation fluence and recovery time in SESAMs show a strong spectral dependence. While the saturation fluence in the SESAM is minimal at the excitonic bandgap, the optimal recovery time and least pulse distortion due to group delay dispersion are found for excitation higher in the first subband. For excitation near the SESAM bandgap,more » the saturation fluence is about one tenth of that in the GSAM. At energies above the bandgap, the fluences in both systems become similar. A strong dependence of the saturation fluence on the pulse width in both systems is caused by carrier relaxation during the pulse. The recovery time in graphene is found to be about two to four times faster than that in the SESAMs. The occurrence of negative differential transmission in graphene is shown to be caused by dopant related carriers. In SESAMs, a negative differential transmission is found when exciting below the excitonic resonance where excitation induced dephasing leads to an enhancement of the absorption. Comparisons of the simulation data to the experiment show a very good quantitative agreement.« less

Low-loss saturable absorbers based on tapered fibers embedded in carbon nanotube/polymer composites

NASA Astrophysics Data System (ADS)

Martinez, Amos; Al Araimi, Mohammed; Dmitriev, Artemiy; Lutsyk, Petro; Li, Shen; Mou, Chengbo; Rozhin, Alexey; Sumetsky, Misha; Turitsyn, Sergei

2017-12-01

The emergence of low-dimensional materials has opened new opportunities in the fabrication of compact nonlinear photonic devices. Single-walled carbon nanotubes were among the first of those materials to attract the attention of the photonics community owing to their high third order susceptibility, broadband operation, and ultrafast response. Saturable absorption, in particular, has become a widespread application for nanotubes in the mode-locking of a fiber laser where they are used as nonlinear passive amplitude modulators to initiate pulsed operation. Numerous approaches have been proposed for the integration of nanotubes in fiber systems; these can be divided into those that rely on direct interaction (where the nanotubes are sandwiched between fiber connectors) and those that rely on lateral interaction with the evanescence field of the propagating wave. Tapered fibers, in particular, offer excellent flexibility to adjust the nonlinearity of nanotube-based devices but suffer from high losses (typically exceeding 50%) and poor saturable to non-saturable absorption ratios (typically above 1:5). In this paper, we propose a method to fabricate carbon nanotube saturable absorbers with controllable saturation power, low-losses (as low as 15%), and large saturable to non-saturable loss ratios approaching 1:1. This is achieved by optimizing the procedure of embedding tapered fibers in low-refractive index polymers. In addition, this study sheds light in the operation of these devices, highlighting a trade-off between losses and saturation power and providing guidelines for the design of saturable absorbers according to their application.

Saturation meter

DOEpatents

Gregurech, S.

1984-08-01

A saturation meter for use in a pressurized water reactor plant comprising a differential pressure transducer having a first and second pressure sensing means and an alarm. The alarm is connected to the transducer and is preset to activate at a level of saturation prior to the formation of a steam void in the reactor vessel.

Top-gated chemical vapor deposition grown graphene transistors with current saturation.

PubMed

Bai, Jingwei; Liao, Lei; Zhou, Hailong; Cheng, Rui; Liu, Lixin; Huang, Yu; Duan, Xiangfeng

2011-06-08

Graphene transistors are of considerable interest for radio frequency (rf) applications. In general, transistors with large transconductance and drain current saturation are desirable for rf performance, which is however nontrivial to achieve in graphene transistors. Here we report high-performance top-gated graphene transistors based on chemical vapor deposition (CVD) grown graphene with large transconductance and drain current saturation. The graphene transistors were fabricated with evaporated high dielectric constant material (HfO(2)) as the top-gate dielectrics. Length scaling studies of the transistors with channel length from 5.6 μm to 100 nm show that complete current saturation can be achieved in 5.6 μm devices and the saturation characteristics degrade as the channel length shrinks down to the 100-300 nm regime. The drain current saturation was primarily attributed to drain bias induced shift of the Dirac points. With the selective deposition of HfO(2) gate dielectrics, we have further demonstrated a simple scheme to realize a 300 nm channel length graphene transistors with self-aligned source-drain electrodes to achieve the highest transconductance of 250 μS/μm reported in CVD graphene to date.

Green Light Pulse Oximeter

DOEpatents

Scharf, John Edward

1998-11-03

A reflectance pulse oximeter that determines oxygen saturation of hemoglobin using two sources of electromagnetic radiation in the green optical region, which provides the maximum reflectance pulsation spectrum. The use of green light allows placement of an oximetry probe at central body sites (e.g., wrist, thigh, abdomen, forehead, scalp, and back). Preferably, the two green light sources alternately emit light at 560 nm and 577 nm, respectively, which gives the biggest difference in hemoglobin extinction coefficients between deoxyhemoglobin, RHb, and oxyhemoglobin, HbO.sub.2.

Density measurement in air with saturable absorbing seed gas

NASA Technical Reports Server (NTRS)

Baganoff, D.

1982-01-01

Approaches which have the potential to make density measurements in a compressible flow, where one or more laser beams are used as probes, were investigated. Saturation in sulfur hexafluoride iodine and a crossed beam technique where one beam acts as a saturating beam and the other is at low intensity and acts as a probe beam are considered. It is shown that a balance between an increase in fluorescence intensity with increasing pressure from line broadening and the normal decrease in intensity with increasing pressure from quenching can be used to develop a linear relation between fluorescence intensity and number density and lead to a new density measurement scheme. The method is used to obtain a density image of the cross section of an iodine seeded underexpanded supersonic jet of nitrogen, by illuminating the cross section by a sheet of laser light.

Dynamics of an eco-epidemiological model with saturated incidence rate

NASA Astrophysics Data System (ADS)

Suryanto, Agus

2017-03-01

In this paper we study the effect of prey infection on the modified Leslie-Gower predator-prey model with saturated incidence rate. The model will be analyzed dynamically to find the equilibria and their existence conditions as well as their local stability conditions. It is found that there are six type of equilibria, namely the extinction of both prey and predator point, the extinction of infective prey and predator point, the extinction of predator point, the extinction of prey point, the extinction of infective prey point and the interior point. The first four equilibrium points are always unstable, while the last two equilibria are conditionally stable. We also find that the system undergoes Hopf bifurcation around the interior point which is controlled by the rate of infection. To illustrate our analytical results, we show some numerical results.

Measurements of Capillary Pressure-Saturation Relationships for Silica Sands Using Light Transmission Visualization and a Rapid Pseudo Static Methods

EPA Science Inventory

Measurement of water saturation in porous media is essential for many types of studies including subsurface water flow, subsurface colloids transport and contaminant remediation to name a few. Water saturation (S) in porous media is dependent on the capillary pressure (Pc) which,...

Saturated Imaging for Inspecting Transparent Aesthetic Defects in a Polymeric Polarizer with Black and White Stripes.

PubMed

Yu, Cilong; Chen, Peibing; Zhong, Xiaopin; Pan, Xizhou; Deng, Yuanlong

2018-05-07

Machine vision systems have been widely used in industrial production lines because of their automation and contactless inspection mode. In polymeric polarizers, extremely slight transparent aesthetic defects are difficult to detect and characterize through conventional illumination. To inspect such defects rapidly and accurately, a saturated imaging technique was proposed, which innovatively uses the characteristics of saturated light in imaging by adjusting the light intensity, exposure time, and camera gain. An optical model of defect was established to explain the theory by simulation. Based on the optimum experimental conditions, active two-step scanning was conducted to demonstrate the feasibility of this detection scheme, and the proposed method was found to be efficient for real-time and in situ inspection of defects in polymer films and products.

Lipid order, saturation and surface property relationships: a study of human meibum saturation.

PubMed

Mudgil, Poonam; Borchman, Douglas; Yappert, Marta C; Duran, Diana; Cox, Gregory W; Smith, Ryan J; Bhola, Rahul; Dennis, Gary R; Whitehall, John S

2013-11-01

Tear film stability decreases with age however the cause(s) of the instability are speculative. Perhaps the more saturated meibum from infants may contribute to tear film stability. The meibum lipid phase transition temperature and lipid hydrocarbon chain order at physiological temperature (33 °C) decrease with increasing age. It is reasonable that stronger lipid-lipid interactions could stabilize the tear film since these interactions must be broken for tear break up to occur. In this study, meibum from a pool of adult donors was saturated catalytically. The influence of saturation on meibum hydrocarbon chain order was determined by infrared spectroscopy. Meibum is in an anhydrous state in the meibomian glands and on the surface of the eyelid. The influence of saturation on the surface properties of meibum was determined using Langmuir trough technology. Saturation of native human meibum did not change the minimum or maximum values of hydrocarbon chain order so at temperatures far above or below the phase transition of human meibum, saturation does not play a role in ordering or disordering the lipid hydrocarbon chains. Saturation did increase the phase transition temperature in human meibum by over 20 °C, a relatively high amount. Surface pressure-area studies showing the late take off and higher maximum surface pressure of saturated meibum compared to native meibum suggest that the saturated meibum film is quite molecularly ordered (stiff molecular arrangement) and elastic (molecules are able to rearrange during compression and expansion) compared with native meibum films which are more fluid agreeing with the infrared spectroscopic results of this study. In saturated meibum, the formation of compacted ordered islands of lipids above the surfactant layer would be expected to decrease the rate of evaporation compared to fluid and more loosely packed native meibum. Higher surface pressure observed with films of saturated meibum compared to native meibum

10. LIGHT TOWER, VIEW NORTHEAST FROM LIGHT PLATFORM, SOUTHWEST SIDE ...

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

10. LIGHT TOWER, VIEW NORTHEAST FROM LIGHT PLATFORM, SOUTHWEST SIDE OF BOAT HOUSE AND KEEPER'S HOUSE, WITH DETAIL OF RAILING IN FOREGROUND - Grindle Point Light Station, Western end of Ferry Road on Grindle Point, Islesboro, Waldo County, ME

Trade-offs between light interception and leaf water shedding: a comparison of shade- and sun-adapted species in a subtropical rainforest.

PubMed

Meng, Fengqun; Cao, Rui; Yang, Dongmei; Niklas, Karl J; Sun, Shucun

2014-01-01

Species in high-rainfall regions have two major alternative approaches to quickly drain off water, i.e., increasing leaf inclination angles relative to the horizontal plane, or developing long leaf drip tips. We hypothesized that shade-adapted species will have more pronounced leaf drip tips but not greater inclination angles (which can reduce the ability to intercept light) compared to sun-adapted species and that length of leaf drip tips will be negatively correlated with photosynthetic capacity [characterized by light-saturated net photosynthetic rates (Amax), associated light compensation points (LCP), and light saturation points (LSP)]. We tested this hypothesis by measuring morphological and physiological traits that are associated with light-interception and water shedding for seven shade-adapted shrub species, ten sun-adapted understory shrub species, and 15 sun-adapted tree species in a subtropical Chinese rainforest, where mean annual precipitation is around 1,600 mm. Shade-adapted understory species had lower LMA, Amax, LSP, and LCP compared to understory or canopy sun-adapted species; their leaf and twig inclination angles were significantly smaller and leaf drip tips were significantly longer than those in sun-adapted species. This suggests that shade-adapted understory species tend to develop pronounced leaf drip tips but not large leaf inclination angles to shed water. The length of leaf drip tips was negatively correlated with leaf inclination angles and photosynthetic capacity. These relationships were consistent between ordinary regression and phylogenetic generalized least squares analyses. Our study illustrates the trade-offs between light interception and leaf water shedding and indicates that length of leaf drip tips can be used as an indicator of adaptation to shady conditions and overall photosynthetic performance of shrub species in subtropical rainforests.

Neuronal mechanisms underlying differences in spatial resolution between darks and lights in human vision.

PubMed

Pons, Carmen; Mazade, Reece; Jin, Jianzhong; Dul, Mitchell W; Zaidi, Qasim; Alonso, Jose-Manuel

2017-12-01

Artists and astronomers noticed centuries ago that humans perceive dark features in an image differently from light ones; however, the neuronal mechanisms underlying these dark/light asymmetries remained unknown. Based on computational modeling of neuronal responses, we have previously proposed that such perceptual dark/light asymmetries originate from a luminance/response saturation within the ON retinal pathway. Consistent with this prediction, here we show that stimulus conditions that increase ON luminance/response saturation (e.g., dark backgrounds) or its effect on light stimuli (e.g., optical blur) impair the perceptual discrimination and salience of light targets more than dark targets in human vision. We also show that, in cat visual cortex, the magnitude of the ON luminance/response saturation remains relatively constant under a wide range of luminance conditions that are common indoors, and only shifts away from the lowest luminance contrasts under low mesopic light. Finally, we show that the ON luminance/response saturation affects visual salience mostly when the high spatial frequencies of the image are reduced by poor illumination or optical blur. Because both low luminance and optical blur are risk factors in myopia, our results suggest a possible neuronal mechanism linking myopia progression with the function of the ON visual pathway.

Neuronal mechanisms underlying differences in spatial resolution between darks and lights in human vision

PubMed Central

Pons, Carmen; Mazade, Reece; Jin, Jianzhong; Dul, Mitchell W.; Zaidi, Qasim; Alonso, Jose-Manuel

2017-01-01

Artists and astronomers noticed centuries ago that humans perceive dark features in an image differently from light ones; however, the neuronal mechanisms underlying these dark/light asymmetries remained unknown. Based on computational modeling of neuronal responses, we have previously proposed that such perceptual dark/light asymmetries originate from a luminance/response saturation within the ON retinal pathway. Consistent with this prediction, here we show that stimulus conditions that increase ON luminance/response saturation (e.g., dark backgrounds) or its effect on light stimuli (e.g., optical blur) impair the perceptual discrimination and salience of light targets more than dark targets in human vision. We also show that, in cat visual cortex, the magnitude of the ON luminance/response saturation remains relatively constant under a wide range of luminance conditions that are common indoors, and only shifts away from the lowest luminance contrasts under low mesopic light. Finally, we show that the ON luminance/response saturation affects visual salience mostly when the high spatial frequencies of the image are reduced by poor illumination or optical blur. Because both low luminance and optical blur are risk factors in myopia, our results suggest a possible neuronal mechanism linking myopia progression with the function of the ON visual pathway. PMID:29196762

Scaled SFS method for Lambertian surface 3D measurement under point source lighting.

PubMed

Ma, Long; Lyu, Yi; Pei, Xin; Hu, Yan Min; Sun, Feng Ming

2018-05-28

A Lambertian surface is a kind of very important assumption in shape from shading (SFS), which is widely used in many measurement cases. In this paper, a novel scaled SFS method is developed to measure the shape of a Lambertian surface with dimensions. In which, a more accurate light source model is investigated under the illumination of a simple point light source, the relationship between surface depth map and the recorded image grayscale is established by introducing the camera matrix into the model. Together with the constraints of brightness, smoothness and integrability, the surface shape with dimensions can be obtained by analyzing only one image using the scaled SFS method. The algorithm simulations show a perfect matching between the simulated structures and the results, the rebuilding root mean square error (RMSE) is below 0.6mm. Further experiment is performed by measuring a PVC tube internal surface, the overall measurement error lies below 2%.

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

PubMed

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

2012-05-01

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

Observation of Reverse Saturable Absorption of an X-ray Laser

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

Cho, B. I.; Cho, M. S.; Kim, M.

A nonlinear absorber in which the excited state absorption is larger than the ground state can undergo a process called reverse saturable absorption. It is a well-known phenomenon in laser physics in the optical regime, but is more difficult to generate in the x-ray regime, where fast nonradiative core electron transitions typically dominate the population kinetics during light matter interactions. Here, we report the first observation of decreasing x-ray transmission in a solid target pumped by intense x-ray free electron laser pulses. The measurement has been made below the K-absorption edge of aluminum, and the x-ray intensity ranges are 10more » 16 –10 17 W=cm 2. It has been confirmed by collisional radiative population kinetic calculations, underscoring the fast spectral modulation of the x-ray pulses and charge states relevant to the absorption and transmission of x-ray photons. The processes shown through detailed simulations are consistent with reverse saturable absorption, which would be the first observation of this phenomena in the x-ray regime. These light matter interactions provide a unique opportunity to investigate optical transport properties in the extreme state of matters, as well as affording the potential to regulate ultrafast x-ray freeelectron laser pulses.« less

Observation of Reverse Saturable Absorption of an X-ray Laser

DOE PAGES

Cho, B. I.; Cho, M. S.; Kim, M.; ...

2017-08-16

A nonlinear absorber in which the excited state absorption is larger than the ground state can undergo a process called reverse saturable absorption. It is a well-known phenomenon in laser physics in the optical regime, but is more difficult to generate in the x-ray regime, where fast nonradiative core electron transitions typically dominate the population kinetics during light matter interactions. Here, we report the first observation of decreasing x-ray transmission in a solid target pumped by intense x-ray free electron laser pulses. The measurement has been made below the K-absorption edge of aluminum, and the x-ray intensity ranges are 10more » 16 –10 17 W=cm 2. It has been confirmed by collisional radiative population kinetic calculations, underscoring the fast spectral modulation of the x-ray pulses and charge states relevant to the absorption and transmission of x-ray photons. The processes shown through detailed simulations are consistent with reverse saturable absorption, which would be the first observation of this phenomena in the x-ray regime. These light matter interactions provide a unique opportunity to investigate optical transport properties in the extreme state of matters, as well as affording the potential to regulate ultrafast x-ray freeelectron laser pulses.« less

Point and path performance of light aircraft: A review and analysis

NASA Technical Reports Server (NTRS)

Smetana, F. O.; Summey, D. C.; Johnson, W. D.

1973-01-01

The literature on methods for predicting the performance of light aircraft is reviewed. The methods discussed in the review extend from the classical instantaneous maximum or minimum technique to techniques for generating mathematically optimum flight paths. Classical point performance techniques are shown to be adequate in many cases but their accuracies are compromised by the need to use simple lift, drag, and thrust relations in order to get closed form solutions. Also the investigation of the effect of changes in weight, altitude, configuration, etc. involves many essentially repetitive calculations. Accordingly, computer programs are provided which can fit arbitrary drag polars and power curves with very high precision and which can then use the resulting fits to compute the performance under the assumption that the aircraft is not accelerating.

A new three-dimensional nonscanning laser imaging system based on the illumination pattern of a point-light-source array

NASA Astrophysics Data System (ADS)

Xia, Wenze; Ma, Yayun; Han, Shaokun; Wang, Yulin; Liu, Fei; Zhai, Yu

2018-06-01

One of the most important goals of research on three-dimensional nonscanning laser imaging systems is the improvement of the illumination system. In this paper, a new three-dimensional nonscanning laser imaging system based on the illumination pattern of a point-light-source array is proposed. This array is obtained using a fiber array connected to a laser array with each unit laser having independent control circuits. This system uses a point-to-point imaging process, which is realized using the exact corresponding optical relationship between the point-light-source array and a linear-mode avalanche photodiode array detector. The complete working process of this system is explained in detail, and the mathematical model of this system containing four equations is established. A simulated contrast experiment and two real contrast experiments which use the simplified setup without a laser array are performed. The final results demonstrate that unlike a conventional three-dimensional nonscanning laser imaging system, the proposed system meets all the requirements of an eligible illumination system. Finally, the imaging performance of this system is analyzed under defocusing situations, and analytical results show that the system has good defocusing robustness and can be easily adjusted in real applications.

Phosphorene quantum dot saturable absorbers for ultrafast fiber lasers

PubMed Central

Du, J.; Zhang, M.; Guo, Z.; Chen, J.; Zhu, X.; Hu, G.; Peng, P.; Zheng, Z.; Zhang, H.

2017-01-01

We fabricate ultrasmall phosphorene quantum dots (PQDs) with an average size of 2.6 ± 0.9 nm using a liquid exfoliation method involving ultrasound probe sonication followed by bath sonication. By coupling the as-prepared PQDs with microfiber evanescent light field, the PQD-based saturable absorber (SA) device exhibits ultrafast nonlinear saturable absorption property, with an optical modulation depth of 8.1% at the telecommunication band. With the integration of the all-fiber PQD-based SA, a continuous-wave passively mode-locked erbium-doped (Er-doped) laser cavity delivers stable, self-starting pulses with a pulse duration of 0.88 ps and at the cavity repetition rate of 5.47 MHz. Our results contribute to the growing body of work studying the nonlinear optical properties of ultrasmall PQDs that present new opportunities of this two-dimensional (2D) nanomaterial for future ultrafast photonic technologies. PMID:28211471

Some Boussinesq Equations with Saturation

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

Christou, M. A.

2010-11-25

We investigate numerically some Boussinesq type equations with square or cubic and saturated nonlinearity. We examine the propagation, interaction and overtake interaction of soliton solutions. Moreover, we examine the effect of the saturation term on the solution and compare it with the classical case of the square or cubic nonlinearity without saturation. We calculate numerically the phase shift experienced by the solitons upon collision and conclude the impact of saturation.

General model for the pointing error analysis of Risley-prism system based on ray direction deviation in light refraction

NASA Astrophysics Data System (ADS)

Zhang, Hao; Yuan, Yan; Su, Lijuan; Huang, Fengzhen; Bai, Qing

2016-09-01

The Risley-prism-based light beam steering apparatus delivers superior pointing accuracy and it is used in imaging LIDAR and imaging microscopes. A general model for pointing error analysis of the Risley prisms is proposed in this paper, based on ray direction deviation in light refraction. This model captures incident beam deviation, assembly deflections, and prism rotational error. We derive the transmission matrixes of the model firstly. Then, the independent and cumulative effects of different errors are analyzed through this model. Accuracy study of the model shows that the prediction deviation of pointing error for different error is less than 4.1×10-5° when the error amplitude is 0.1°. Detailed analyses of errors indicate that different error sources affect the pointing accuracy to varying degree, and the major error source is the incident beam deviation. The prism tilting has a relative big effect on the pointing accuracy when prism tilts in the principal section. The cumulative effect analyses of multiple errors represent that the pointing error can be reduced by tuning the bearing tilting in the same direction. The cumulative effect of rotational error is relative big when the difference of these two prism rotational angles equals 0 or π, while it is relative small when the difference equals π/2. The novelty of these results suggests that our analysis can help to uncover the error distribution and aid in measurement calibration of Risley-prism systems.

Tempel Alive with Light

NASA Technical Reports Server (NTRS)

2005-01-01

This spectacular image of comet Tempel 1 was taken 67 seconds after it obliterated Deep Impact's impactor spacecraft. The image was taken by the high-resolution camera on the mission's flyby craft. Scattered light from the collision saturated the camera's detector, creating the bright splash seen here. Linear spokes of light radiate away from the impact site, while reflected sunlight illuminates most of the comet surface. The image reveals topographic features, including ridges, scalloped edges and possibly impact craters formed long ago.

Controls on Highly Siderophile Element Concentrations in Martian Basalt: Sulfide Saturation and Under-Saturation

NASA Technical Reports Server (NTRS)

Righter, Kevin

2009-01-01

Highly siderophile elements (HSE; Re, Au and the platinum group elements) in shergottites exhibit a wide range from very high, similar to the terrestrial mantle, to very low, similar to sulfide saturated mid ocean ridge basalt (e.g., [1]). This large range has been difficult to explain without good constraints on sulfide saturation or under-saturation [2]. A new model for prediction of sulfide saturation places new constraints on this problem [3]. Shergottite data: For primitive shergottites, pressure and temperature estimates are between 1.2-1.5 GPa, and 1350-1470 C [4]. The range of oxygen fugacities is from FMQ-2 to IW, where the amount of Fe2O3 is low and thus does not have a significant effect on the S saturation values. Finally, the bulk compositions of shergottites have been reported in many recent studies (e.g., [5]). All of this information will be used to test whether shergottites are sulfide saturated [3]. Modeling values and results: The database for HSE partition coefficients has been growing with many new data for silicates and oxides [6-8] to complement a large sulfide database [9- 11]. Combining these data with simple batch melting models allows HSE contents of mantle melts to be estimated for sulfide-bearing vs. sulfide-free mantle. Combining such models with fractional crystallization modeling (e.g., [12]) allows HSE contents of more evolved liquids to be modeled. Most primitive shergottites have high HSE contents (and low S contents) that can be explained by sulfide under-saturated melting of the mantle. An exception is Dhofar 019 which has high S contents and very low HSE contents suggesting sulfide saturation. Most evolved basaltic shergottites have lower S contents than saturation, and intermediate HSE contents that can be explained by olivine, pyroxene, and chromite fractionation. An exception is EET A79001 lithology B, which has very low HSE contents and S contents higher than sulfide saturation values . evidence for sulfide saturation

Corresponding state-based correlations for the temperature-dependent surface tension of saturated hydrocarbons

NASA Astrophysics Data System (ADS)

Tian, Jianxiang; Zhang, Cuihua; Zhang, Laibin; Zheng, Mengmeng; Liu, Shuzhen

2017-10-01

Based on the recent progresses on the corresponding state-based correlations for the temperature-dependent surface tension of saturated fluids [I. Cachadiña, A. Mulero and J. X. Tian, Fluid Phase Equilibr. 442 (2017) 68; J. X. Tian, M. M. Zheng, H. L. Yi, L. B. Zhang and S. Z. Liu, Mod. Phys. Lett. B 31 (2017) 1750110], we proposed a new correlation for saturated hydrocarbons. This correlation includes three fluid-independent parameters and inquires the critical temperature, the triple-point temperature and the surface tension at the triple-point temperature as inputs for each hydrocarbon. Results show that this correlation can reproduce NIST data with absolute average deviation (AAD) less than 1% for 10 out of 19 hydrocarbons and AAD less than 5% for 17 out of 19 hydrocarbons, clearly better than other correlations.

An evaluation of bilateral monitoring of cerebral oxygen saturation during pediatric cardiac surgery.

PubMed

Kussman, Barry D; Wypij, David; DiNardo, James A; Newburger, Jane; Jonas, Richard A; Bartlett, Jodi; McGrath, Ellen; Laussen, Peter C

2005-11-01

Cerebral oximetry is a technique that enables monitoring of regional cerebral oxygenation during cardiac surgery. In this study, we evaluated differences in bi-hemispheric measurement of cerebral oxygen saturation using near-infrared spectroscopy in 62 infants undergoing biventricular repair without aortic arch reconstruction. Left and right regional cerebral oxygen saturation index (rSO2i) were recorded continuously after the induction of anesthesia, and data were analyzed at 12 time points. Baseline rSO2i measurements were left 65 +/- 13 and right 66 +/- 13 (P = 0.17). Mean left and right rSO2i measurements were similar (< or =2 percentage points/absolute scale units) before, during, and after cardiopulmonary bypass, irrespective of the use of deep hypothermic circulatory arrest. Further longitudinal neurological outcome studies are required to determine whether uni- or bi-hemispheric monitoring is required in this patient population.

Effect of light on N2 fixation and net nitrogen release of Trichodesmium in a field study

NASA Astrophysics Data System (ADS)

Lu, Yangyang; Wen, Zuozhu; Shi, Dalin; Chen, Mingming; Zhang, Yao; Bonnet, Sophie; Li, Yuhang; Tian, Jiwei; Kao, Shuh-Ji

2018-01-01

Dinitrogen fixation (NF) by marine cyanobacteria is an important pathway to replenish the oceanic bioavailable nitrogen inventory. Light is the key to modulating NF; however, field studies investigating the light response curve (NF-I curve) of NF rate and the effect of light on diazotroph-derived nitrogen (DDN) net release are relatively sparse in the literature, hampering prediction using models. A dissolution method was applied using uncontaminated 15N2 gas to examine how the light changes may influence the NF intensity and DDN net release in the oligotrophic ocean. Experiments were conducted at stations with diazotrophs dominated by filamentous cyanobacterium Trichodesmium spp. in the western Pacific and the South China Sea. The effect of light on carbon fixation (CF) was measured in parallel using the 13C tracer method specifically for a station characterized by Trichodesmium bloom. Both NF-I and CF-I curves showed a Ik (light saturation coefficient) range of 193 to 315 µE m-2 s-1, with light saturation at around 400 µE m-2 s-1. The proportion of DDN net release ranged from ˜ 6 to ˜ 50 %, suggesting an increasing trend as the light intensity decreased. At the Trichodesmium bloom station, we found that the CF / NF ratio was light-dependent and the ratio started to increase as light was lower than the carbon compensation point of 200 µE m-2 s-1. Under low-light stress, Trichodesmium physiologically preferred to allocate more energy for CF to alleviate the intensive carbon consumption by respiration; thus, there is a metabolism tradeoff between CF and NF pathways. Results showed that short-term ( < 24 h) light change modulates the physiological state, which subsequently determined the C / N metabolism and DDN net release by Trichodesmium. Reallocation of energy associated with the variation in light intensity would be helpful for prediction of the global biogeochemical cycle of N by models involving Trichodesmium blooms.

Stroke saturation on a MEMS deformable mirror for woofer-tweeter adaptive optics.

PubMed

Morzinski, Katie; Macintosh, Bruce; Gavel, Donald; Dillon, Daren

2009-03-30

High-contrast imaging of extrasolar planet candidates around a main-sequence star has recently been realized from the ground using current adaptive optics (AO) systems. Advancing such observations will be a task for the Gemini Planet Imager, an upcoming "extreme" AO instrument. High-order "tweeter" and low-order "woofer" deformable mirrors (DMs) will supply a >90%-Strehl correction, a specialized coronagraph will suppress the stellar flux, and any planets can then be imaged in the "dark hole" region. Residual wavefront error scatters light into the DM-controlled dark hole, making planets difficult to image above the noise. It is crucial in this regard that the high-density tweeter, a micro-electrical mechanical systems (MEMS) DM, have sufficient stroke to deform to the shapes required by atmospheric turbulence. Laboratory experiments were conducted to determine the rate and circumstance of saturation, i.e. stroke insufficiency. A 1024-actuator 1.5-microm-stroke MEMS device was empirically tested with software Kolmogorov-turbulence screens of r(0) =10-15 cm. The MEMS when solitary suffered saturation approximately 4% of the time. Simulating a woofer DM with approximately 5-10 actuators across a 5-m primary mitigated MEMS saturation occurrence to a fraction of a percent. While no adjacent actuators were saturated at opposing positions, mid-to-high-spatial-frequency stroke did saturate more frequently than expected, implying that correlations through the influence functions are important. Analytical models underpredict the stroke requirements, so empirical studies are important.

Percolation Pore Network Study on the Residue Gas Saturation of Dry Reservoir Rocks

NASA Astrophysics Data System (ADS)

Cheng, T.; Tang, Y. B.; Zou, G. Y.; Jiang, K.; Li, M.

2014-12-01

We tried to model the effect of pore size heterogeneity and pore connectivity on the residue gas saturation for dry gas reservoir rocks. If we consider that snap-off does not exist and only piston displacement takes place in all pores with the same size during imbibition process, in the extreme case, the residue gas saturation will be equal to zero. Thus we can suppose that the residue gas saturation of dry rocks is mainly controlled by the pore size distribution. To verify the assumption, percolation pore networks (i.e., three-dimensional simple cubic (SC) and body-center cubic (BCC)) were used in the study. The connectivity and the pore size distribution in percolation pore network could be changed randomly. The concept of water phase connectivity zw(i.e., water coordination number) and gas phase connectivity zg (i.e., gas coordination number) was introduced here. zw and zg will change during simulation and can be estimated numerically from the results of simulations through gradually saturated networks by water. The Simulation results show that when zg less than or equal to 1.5 during water quasi - static imbibition, the gas will be trapped in rock pores. Network simulation results also shows that the residue gas saturation Srg follows a power law relationship (i.e.,Srg∝σrα, where σr is normalized standard deviation of the pore radius distribution, and exponent α is a function of coordination number). This indicates that the residue gas saturation has no explicit relationship with porosity and permeability as it should have in light of previous study, pore radius distribution is the principal factor in determining the residue gas saturation of dry reservoir rocks.

Compressed liquid densities, saturated liquid densities, and vapor pressures of 1,1-difluoroethane

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

Defibaugh, D.R.; Morrison, G.

1996-05-01

The compressed liquid densities and vapor pressures of 1,1-difluoroethane (HFC-152a) have been measured, correlated, and compared with other data. The liquid densities were measured with a combined standard uncertainty of {+-}0.05% using a vibrating tube densimeter over a temperature range of 243 K to 371 K and at pressures from near the saturated vapor pressure to 6,500 kPa; thus the data extend nearly to the critical point ({Tc} = 386.41 K and P{sub c} = 4514.7 kPa). The vapor pressures were measured with a combined standard uncertainty of {+-}0.02% using a stainless steel ebulliometer in the temperature range from 280more » K to 335 K. Saturated liquid densities were calculated by extrapolating the compressed liquid isotherms to the saturation pressure.« less

Simultaneous, noninvasive, in vivo, continuous monitoring of hematocrit, vascular volume, hemoglobin oxygen saturation, pulse rate and breathing rate in humans and other animal models using a single light source

NASA Astrophysics Data System (ADS)

Dent, Paul; Tun, Sai Han; Fillioe, Seth; Deng, Bin; Satalin, Josh; Nieman, Gary; Wilcox, Kailyn; Searles, Quinn; Narsipur, Sri; Peterson, Charles M.; Goodisman, Jerry; Mostrom, James; Steinmann, Richard; Chaiken, J.

2018-02-01

We previously reported a new algorithm "PV[O]H" for continuous, noninvasive, in vivo monitoring of hematocrit changes in blood and have since shown its utility for monitoring in humans during 1) hemodialysis, 2) orthostatic perturbations and 3) during blood loss and fluid replacement in a rat model. We now show that the algorithm is sensitive to changes in hemoglobin oxygen saturation. We document the phenomenology of the effect and explain the effect using new results obtained from humans and rat models. The oxygen sensitivity derives from the differential absorption of autofluorescence originating in the static tissues by oxy and deoxy hemoglobin. Using this approach we show how to perform simultaneous, noninvasive, in vivo, continuous monitoring of hematocrit, vascular volume, hemoglobin oxygen saturation, pulse rate and breathing rate in mammals using a single light source. We suspect that monitoring of changes in this suite of vital signs can be provided with improved time response, sensitivity and precision compared to existing methodologies. Initial results also offer a more detailed glimpse into the systemic oxygen transport in the circulatory system of humans.

Cylindrical angular spectrum using Fourier coefficients of point light source and its application to fast hologram calculation.

PubMed

Oh, Seungtaik; Jeong, Il Kwon

2015-11-16

We will introduce a new simple analytic formula of the Fourier coefficient of the 3D field distribution of a point light source to generate a cylindrical angular spectrum which captures the object wave in 360° in the 3D Fourier space. Conceptually, the cylindrical angular spectrum can be understood as a cylindrical version of the omnidirectional spectral approach of Sando et al. Our Fourier coefficient formula is based on an intuitive observation that a point light radiates uniformly in all directions. Our formula is defined over all frequency vectors lying on the entire sphere in the 3D Fourier space and is more natural and computationally more efficient for all around recording of the object wave than that of the previous omnidirectional spectral method. A generalized frequency-based occlusion culling method for an arbitrary complex object is also proposed to enhance the 3D quality of a hologram. As a practical application of the cylindrical angular spectrum, an interactive hologram example is presented together with implementation details.

Josephson parametric converter saturation and higher order effects

NASA Astrophysics Data System (ADS)

Liu, G.; Chien, T.-C.; Cao, X.; Lanes, O.; Alpern, E.; Pekker, D.; Hatridge, M.

2017-11-01

Microwave parametric amplifiers based on Josephson junctions have become indispensable components of many quantum information experiments. One key limitation which has not been well predicted by theory is the gain saturation behavior which limits the amplifier's ability to process large amplitude signals. The typical explanation for this behavior in phase-preserving amplifiers based on three-wave mixing, such as the Josephson Parametric Converter, is pump depletion, in which the consumption of pump photons to produce amplification results in a reduction in gain. However, in this work, we present experimental data and theoretical calculations showing that the fourth-order Kerr nonlinearities inherent in Josephson junctions are the dominant factor. The Kerr-based theory has the unusual property of causing saturation to both lower and higher gains, depending on bias conditions. This work presents an efficient methodology for optimizing device performance in the presence of Kerr nonlinearities while retaining device tunability and points to the necessity of controlling higher-order Hamiltonian terms to make further improvements in parametric devices.

Regional impacts of iron-light colimitation in a global biogeochemical model

NASA Astrophysics Data System (ADS)

Galbraith, E. D.; Gnanadesikan, A.; Dunne, J. P.; Hiscock, M. R.

2010-03-01

Laboratory and field studies have revealed that iron has multiple roles in phytoplankton physiology, with particular importance for light-harvesting cellular machinery. However, although iron-limitation is explicitly included in numerous biogeochemical/ecosystem models, its implementation varies, and its effect on the efficiency of light harvesting is often ignored. Given the complexity of the ocean environment, it is difficult to predict the consequences of applying different iron limitation schemes. Here we explore the interaction of iron and nutrient cycles in an ocean general circulation model using a new, streamlined model of ocean biogeochemistry. Building on previously published parameterizations of photoadaptation and export production, the Biogeochemistry with Light Iron Nutrients and Gasses (BLING) model is constructed with only four explicit tracers but including macronutrient and micronutrient limitation, light limitation, and an implicit treatment of community structure. The structural simplicity of this computationally-inexpensive model allows us to clearly isolate the global effect that iron availability has on maximum light-saturated photosynthesis rates vs. the effect iron has on photosynthetic efficiency. We find that the effect on light-saturated photosynthesis rates is dominant, negating the importance of photosynthetic efficiency in most regions, especially the cold waters of the Southern Ocean. The primary exceptions to this occur in iron-rich regions of the Northern Hemisphere, where high light-saturated photosynthesis rates allow photosynthetic efficiency to play a more important role. In other words, the ability to efficiently harvest photons has little effect in regions where light-saturated growth rates are low. Additionally, we speculate that the phytoplankton cells dominating iron-limited regions tend to have relatively high photosynthetic efficiency, due to reduced packaging effects. If this speculation is correct, it would imply that

Tilted Light Sheet Microscopy with 3D Point Spread Functions for Single-Molecule Super-Resolution Imaging in Mammalian Cells.

PubMed

Gustavsson, Anna-Karin; Petrov, Petar N; Lee, Maurice Y; Shechtman, Yoav; Moerner, W E

2018-02-01

To obtain a complete picture of subcellular nanostructures, cells must be imaged with high resolution in all three dimensions (3D). Here, we present tilted light sheet microscopy with 3D point spread functions (TILT3D), an imaging platform that combines a novel, tilted light sheet illumination strategy with engineered long axial range point spread functions (PSFs) for low-background, 3D super localization of single molecules as well as 3D super-resolution imaging in thick cells. TILT3D is built upon a standard inverted microscope and has minimal custom parts. The axial positions of the single molecules are encoded in the shape of the PSF rather than in the position or thickness of the light sheet, and the light sheet can therefore be formed using simple optics. The result is flexible and user-friendly 3D super-resolution imaging with tens of nm localization precision throughout thick mammalian cells. We validated TILT3D for 3D super-resolution imaging in mammalian cells by imaging mitochondria and the full nuclear lamina using the double-helix PSF for single-molecule detection and the recently developed Tetrapod PSF for fiducial bead tracking and live axial drift correction. We envision TILT3D to become an important tool not only for 3D super-resolution imaging, but also for live whole-cell single-particle and single-molecule tracking.

Tilted light sheet microscopy with 3D point spread functions for single-molecule super-resolution imaging in mammalian cells

NASA Astrophysics Data System (ADS)

Gustavsson, Anna-Karin; Petrov, Petar N.; Lee, Maurice Y.; Shechtman, Yoav; Moerner, W. E.

2018-02-01

To obtain a complete picture of subcellular nanostructures, cells must be imaged with high resolution in all three dimensions (3D). Here, we present tilted light sheet microscopy with 3D point spread functions (TILT3D), an imaging platform that combines a novel, tilted light sheet illumination strategy with engineered long axial range point spread functions (PSFs) for low-background, 3D super localization of single molecules as well as 3D super-resolution imaging in thick cells. TILT3D is built upon a standard inverted microscope and has minimal custom parts. The axial positions of the single molecules are encoded in the shape of the PSF rather than in the position or thickness of the light sheet, and the light sheet can therefore be formed using simple optics. The result is flexible and user-friendly 3D super-resolution imaging with tens of nm localization precision throughout thick mammalian cells. We validated TILT3D for 3D superresolution imaging in mammalian cells by imaging mitochondria and the full nuclear lamina using the double-helix PSF for single-molecule detection and the recently developed Tetrapod PSF for fiducial bead tracking and live axial drift correction. We envision TILT3D to become an important tool not only for 3D super-resolution imaging, but also for live whole-cell single-particle and single-molecule tracking.

New Primary Dew-Point Generators at HMI/FSB-LPM in the Range from -70 °C to +60 °C

NASA Astrophysics Data System (ADS)

Zvizdic, Davor; Heinonen, Martti; Sestan, Danijel

2012-09-01

To extend the dew-point range and to improve the uncertainties of the humidity scale realization at HMI/FSB-LPM, new primary low- and high-range dew-point generators were developed and implemented in cooperation with MIKES, in 2009 through EUROMET Project No. 912. The low-range saturator is designed for primary realization of the dew-point temperature scale from -70 °C to + 5 °C, while the high-range saturator covers the range from 1 °C to 60 °C. The system is designed as a single-pressure, single-pass dew-point generator. MIKES designed and constructed both the saturators to be implemented in dew-point calibration systems at LPM. The LPM took care of purchasing and adapting liquid baths, of implementing the temperature and pressure measurement equipment appropriate for use in the systems, and development of gas preparation and flow control systems as well as of the computer-based automated data acquisition. The principle and the design of the generator are described in detail and schematically depicted. The tests were performed at MIKES to investigate how close both the saturators are to an ideal saturator. Results of the tests show that both the saturators are efficient enough for a primary realization of the dew-point temperature scale from -70 °C to + 60 °C, in the specified flow-rate ranges. The estimated standard uncertainties due to the non-ideal saturation efficiency are between 0.02 °C and 0.05 °C.

Effects of Hypothermic Cardiopulmonary Bypass on Internal Jugular Bulb Venous Oxygen Saturation, Cerebral Oxygen Saturation, and Bispectral Index in Pediatric Patients Undergoing Cardiac Surgery: A Prospective Study.

PubMed

Hu, Zhiyong; Xu, Lili; Zhu, Zhirui; Seal, Robert; McQuillan, Patrick M

2016-01-01

The objective of this study was to evaluate the effect of hypothermic cardiopulmonary bypass (CPB) on cerebral oxygen saturation (rSO2), internal jugular bulb venous oxygen saturation (SjvO2), mixed venous oxygen saturation (SvO2), and bispectral index (BIS) used to monitor cerebral oxygen balance in pediatric patients.Sixty American Society of Anesthesiologists Class II-III patients aged 1 to 4 years old with congenital heart disease scheduled for elective cardiac surgery were included in this study. Temperature, BIS, rSO2, mean arterial pressure, central venous pressure, cerebral perfusion pressure (CPP), and hematocrit were recorded. Internal jugular bulb venous oxygen saturation and SvO2 were obtained from blood gas analysis at the time points: after induction of anesthesia (T0), beginning of CPB (T1), ascending aortic occlusion (T2), 20 minutes after initiating CPB (T3), coronary reperfusion (T4), separation from CPB (T5), and at the end of operation (T6). The effect of hypothermia or changes in CPP on rSO2, SjvO2, SvO2, and BIS were analyzed.Compared with postinduction baseline values, rSO2 significantly decreased at all-time points: onset of extracorporeal circulation, ascending aortic occlusion, 20 minutes after CPB initiation, coronary reperfusion, and separation from CPB (P < 0.05). Compared with measurements made following induction of anesthesia, SjvO2 significantly increased with initiation of CPB, ascending aortic occlusion, 20 minutes after initiating CPB, coronary reperfusion, and separation from CPB (P < 0.05). Compared with induction of anesthesia, BIS significantly decreased with the onset of CPB, aortic cross clamping, 20 minutes after initiating CPB, and coronary reperfusion (P < 0.05). Bispectral index increased following separation from CPB. There was no significant change in SvO2 during cardiopulmonary bypass (P > 0.05). Correlation analysis demonstrated that rSO2 was positively related to CPP (r = 0.687, P = 0

3D point cloud analysis of structured light registration in computer-assisted navigation in spinal surgeries

NASA Astrophysics Data System (ADS)

Gupta, Shaurya; Guha, Daipayan; Jakubovic, Raphael; Yang, Victor X. D.

2017-02-01

Computer-assisted navigation is used by surgeons in spine procedures to guide pedicle screws to improve placement accuracy and in some cases, to better visualize patient's underlying anatomy. Intraoperative registration is performed to establish a correlation between patient's anatomy and the pre/intra-operative image. Current algorithms rely on seeding points obtained directly from the exposed spinal surface to achieve clinically acceptable registration accuracy. Registration of these three dimensional surface point-clouds are prone to various systematic errors. The goal of this study was to evaluate the robustness of surgical navigation systems by looking at the relationship between the optical density of an acquired 3D point-cloud and the corresponding surgical navigation error. A retrospective review of a total of 48 registrations performed using an experimental structured light navigation system developed within our lab was conducted. For each registration, the number of points in the acquired point cloud was evaluated relative to whether the registration was acceptable, the corresponding system reported error and target registration error. It was demonstrated that the number of points in the point cloud neither correlates with the acceptance/rejection of a registration or the system reported error. However, a negative correlation was observed between the number of the points in the point-cloud and the corresponding sagittal angular error. Thus, system reported total registration points and accuracy are insufficient to gauge the accuracy of a navigation system and the operating surgeon must verify and validate registration based on anatomical landmarks prior to commencing surgery.

Light trapping and circularly polarization at a Dirac point in 2D plasma photonic crystals

NASA Astrophysics Data System (ADS)

Li, Qian; Hu, Lei; Mao, Qiuping; Jiang, Haiming; Hu, Zhijia; Xie, Kang; Wei, Zhang

2018-03-01

Light trapping at the Dirac point in 2D plasma photonic crystal has been obtained. The new localized mode, Dirac mode, is attributable to neither photonic bandgap nor total internal reflection. It exhibits a unique algebraic profile and possesses a high-Q factor resonator of about 105. The Dirac point could be modulated by tuning the filling factor, plasma frequency and plasma cyclotron frequency, respectively. When a magnetic field parallel to the wave vector is applied, Dirac modes for right circularly polarized and left circularly polarized waves could be obtained at different frequencies, and the Q factor could be tuned. This property will add more controllability and flexibility to the design and modulation of novel photonic devices. It is also valuable for the possibilities of Dirac modes in photonic crystal containing other kinds of metamaterials.

Population gratings in saturable optical fibers with randomly oriented rare-earth ions

NASA Astrophysics Data System (ADS)

Stepanov, S.; Martinez, L. M.; Hernandez, E. H.; Agruzov, P.; Shamray, A.

2015-07-01

Formation of the dynamic population gratings in optical fibers with randomly oriented rare-earth ions is analyzed with a special interest to the grating component for readout with the orthogonal light polarization. It is shown that as compared with a simple model case of the collinearly oriented dipole-like centers their random orientation leads to approximately 2-times growth of the effective saturation power P sat when it is estimated from the incident power dependence of the fiber absorption or from that of the fluorescence intensity. An optimal incident power, for which the maximum of the dynamic population grating amplitude for collinear light polarization is observed, also follows this change in P sat, while formation of the grating for orthogonal polarization needs essentially higher light power. The reduced anisotropy of the active centers, which is in charge of the experimentally observed weakening of the polarization hole burning (PHB) and of the fluorescence polarization, compensates in some way the effect of random ion orientation. The ratio between the maximum conventional (i.e. for the interacting waves collinear polarizations) two-wave mixing (TWM) amplitude and the initial not saturable fiber optical density proves to be, however, nearly the same as in the model case of collinearly oriented dipoles. The ratio between the PHB effect and the amplitude of the anisotropic grating, which is responsible for TWM of the orthogonally polarized waves, is also not influenced significantly by the reduced anisotropy of ions.

Resolving biodegradation patterns of persistent saturated hydrocarbons in weathered oil samples from the Deepwater Horizon disaster.

PubMed

Gros, Jonas; Reddy, Christopher M; Aeppli, Christoph; Nelson, Robert K; Carmichael, Catherine A; Arey, J Samuel

2014-01-01

Biodegradation plays a major role in the natural attenuation of oil spills. However, limited information is available about biodegradation of different saturated hydrocarbon classes in surface environments, despite that oils are composed mostly of saturates, due to the limited ability of conventional gas chromatography (GC) to resolve this compound group. We studied eight weathered oil samples collected from four Gulf of Mexico beaches 12-19 months after the Deepwater Horizon disaster. Using comprehensive two-dimensional gas chromatography (GC × GC), we successfully separated, identified, and quantified several distinct saturates classes in these samples. We find that saturated hydrocarbons eluting after n-C22 dominate the GC-amenable fraction of these weathered samples. This compound group represented 8-10%, or 38-68 thousand metric tons, of the oil originally released from Macondo well. Saturates in the n-C22 to n-C29 elution range were found to be partly biodegraded, but to different relative extents, with ease of biodegradation decreasing in the following order: n-alkanes > methylalkanes and alkylcyclopentanes+alkylcyclohexanes > cyclic and acyclic isoprenoids. We developed a new quantitative index designed to characterize biodegradation of >n-C22 saturates. These results shed new light onto the environmental fate of these persistent, hydrophobic, and mostly overlooked compounds in the unresolved complex mixtures (UCM) of weathered oils.

Branch point reconstructors for discontinuous light phase functions

NASA Astrophysics Data System (ADS)

Le Bigot, Eric O.; Wild, Walter J.; Kibblewhite, Edward J.

1998-09-01

The study of phase discontinuities caused by atmospheric turbulence is a recent research topic; their study might yield significant improvements in high-quality adaptive optics systems, laser weapons and laser communication. We present in this paper an introduction to discontinuities in the light phase. We also provide a geometrical description of phase discontinuities, a study of their effect on Hartmann-Shack sensor measurements, as well as algorithms for measuring discontinuous light phases and the position of phase discontinuities.

Point of data saturation was assessed using resampling methods in a survey with open-ended questions.

PubMed

Tran, Viet-Thi; Porcher, Raphael; Falissard, Bruno; Ravaud, Philippe

2016-12-01

To describe methods to determine sample sizes in surveys using open-ended questions and to assess how resampling methods can be used to determine data saturation in these surveys. We searched the literature for surveys with open-ended questions and assessed the methods used to determine sample size in 100 studies selected at random. Then, we used Monte Carlo simulations on data from a previous study on the burden of treatment to assess the probability of identifying new themes as a function of the number of patients recruited. In the literature, 85% of researchers used a convenience sample, with a median size of 167 participants (interquartile range [IQR] = 69-406). In our simulation study, the probability of identifying at least one new theme for the next included subject was 32%, 24%, and 12% after the inclusion of 30, 50, and 100 subjects, respectively. The inclusion of 150 participants at random resulted in the identification of 92% themes (IQR = 91-93%) identified in the original study. In our study, data saturation was most certainly reached for samples >150 participants. Our method may be used to determine when to continue the study to find new themes or stop because of futility. Copyright © 2016 Elsevier Inc. All rights reserved.

[Light response characteristics of photosynthesis and model comparison of Distylium chinense in different flooding durations].

PubMed

Liu, Ze-bin; Cheng, Rui-mei; Xiao, Wen-fa; Guo, Quan-shui; Wang, Na

2015-04-01

The light responses of photosynthesis of two-year-old Distytum chinense seedlings subjected to a simulated reservoir flooding environment in autumn and winter seasons were measured by using a Li-6400 XT portable photosynthesis system, and the light response curves were fitted and analyzed by three models of the rectangular hyperbola, non-rectangular hyperbola and modified rectangular hyperbola to investigate the applicability of different light response models for the D. chinense in different flooding durations and the adaption regulation of light response parameters to flooding stress. The results showed that the fitting effect of the non-rectangular hyperbola model for light response process of D. chinense under normal growth condition and under short-term flooding (15 days of flooding) was better than that of the other two models, while the fitting effect of the modified rectangular hyperbola model for light response process of D. chinense under longer-term flooding (30, 45 and 60 days of flooding) was better than that of the other two models. The modified rectangular hyperbola model gave the best fitted results of light compensation point (LCP) , maximum net photosynthetic rate (P(n max)) and light saturation point (LSP), and the non-rectangular hyperbola model gave the best fitted result of dark respiration rate (R(d)). The apparent quantum yield (Φ), P(n max) and LSP of D. chinense gradually decreased, and the LCP and R(d) of D. chinense gradually increased in early flooding (30 days), but D. chinense gradually produced adaptability for flooding as the flooding duration continued to increase, and various physiological indexes were gradually stabilized. Thus, this species has adaptability to some degree to the flooding environment.

SolarSoft Desat Package for the Recovery of Saturated AIA Flare Images

NASA Astrophysics Data System (ADS)

Schwartz, Richard Alan; Torre, Gabriele; Piana, Michele; Massone, AnnaMaria

2015-04-01

The dynamic range of EUV images has been limited by the problem of CCD saturation as seen countless times in movies of solare flares made using the Solar Dynamics Observatory’s Atmospheric Imaging Assembly (SDO AIA). Concurrent with the saturation are the eight rays emanating from the saturation locus which are the result of diffraction off the wire meshes that support the EUV passband filters. This is the problem and its solution in a nutshell. By utilizing techniques similar to those used for making images from the rotating modulation collimators on the Ramaty High Energy Solar Spectroscopic Imager (RHESSI) we have developed a software package that can be used to make images of the EUV flare kernels in a highly automated way as described in Schwartz et al. (2014). Starting from cutouts centered around a flaring region, the software uses the point-spread-function (PSF) of the diffraction pattern to identify and reconstruct the region of the primary saturation. The software also uses the best information available to reconstruct the general scene obscured from overflow saturation and subtracts away the diffraction fringes. It is not a total correction for the PSF but is meant to provide the flare images above all. The software is freely available and distributed within the DESAT package of Solar Software.(Schwartz, R. A., Torre, G., & Piana, M. (2014), Astrophysical Journal Letters, 793, LL23 )

Thermal properties of light-weight concrete with waste polypropylene aggregate

NASA Astrophysics Data System (ADS)

Záleská, Martina; Pokorný, Jaroslav; Pavlíková, Milena; Pavlík, Zbyšek

2017-07-01

Thermal properties of a sustainable light-weight concrete incorporating high volume of waste polypropylene as partial substitution of natural aggregate were studied in the paper. Glass fiber reinforced polypropylene (GFPP), a by-product of PP tubes production, partially substituted fine natural silica aggregate in 10, 20, 30, 40, and 50 mass%. In order to quantify the effect of GFPP use on concrete properties, a reference concrete mix without plastic waste was studied as well. For the applied GFPP, bulk density, matrix density, and particle size distribution were measured. Specific attention was paid to thermal transport and storage properties of GFPP that were examined in dependence on compaction time. For the developed light-weight concrete, thermal properties were accessed using transient impulse technique, whereas the measurement was done in dependence on moisture content, from the dry state to fully water saturated state. Additionally, the investigated thermal properties were plotted as function of porosity. The tested light-weight concrete was found to be prospective construction material possessing improved thermal insulation function. Moreover, the reuse of waste plastics in concrete composition was beneficial both from the environmental and financial point of view considering plastics low biodegradability and safe disposal.

Very preterm infants can detect small variations in light levels in incubators.

PubMed

Zores, Claire; Dufour, André; Pebayle, Thierry; Langlet, Claire; Astruc, Dominique; Kuhn, Pierre

2015-10-01

This prospective observational study was designed to improve our understanding of the responses of very preterm infants to light level variations in incubators and to evaluate what determined those reactions. The physiological responses of 27 very preterm infants were analysed following variations in the light level environments of their incubators over 10 hours. Heart and respiratory rates, systemic oxygen saturation and regional cerebral oxygen saturations were recorded using near-infrared spectroscopy, and the variation of each parameter was analysed. We analysed 332 light level changes. Heart rate increased by 3.8 beats per minute (range -2.6 to 12.6), respiratory rate by six cycles per minute (-1.5 to 26) and regional cerebral oxygen saturation by 1.1% (-0.5% to 3.9%) (p < 0.05 each) when delta lux was over 50. Only respiratory rate decreased significantly, by -8.4 cycles per minute (-28 to -0.4), when delta lux was 50 or lower (p < 0.05). The initial level of illumination altered the very preterm infants' responses, with higher reactivity for higher ambient light levels. Very preterm infants reacted to moderate variations in illumination in their incubator, within recommended ranges of light levels, suggesting that they may detect even small light level variations. ©2015 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.

Regional impacts of iron-light colimitation in a global biogeochemical model

NASA Astrophysics Data System (ADS)

Galbraith, E. D.; Gnanadesikan, A.; Dunne, J. P.; Hiscock, M. R.

2009-07-01

Laboratory and field studies have revealed that iron has multiple roles in phytoplankton physiology, with particular importance for light-harvesting cellular machinery. However, although iron-limitation is explicitly included in numerous biogeochemical/ecosystem models, its implementation varies, and its effect on the efficiency of light harvesting is often ignored. Given the complexity of the ocean environment, it is difficult to predict the consequences of applying different iron limitation schemes. Here we explore the interaction of iron and nutrient cycles using a new, streamlined model of ocean biogeochemistry. Building on previously published parameterizations of photoadaptation and export production, the Biogeochemistry with Light Iron Nutrients and Gasses (BLING) model is constructed with only three explicit tracers but including macronutrient and micronutrient limitation, light limitation, and an implicit treatment of community structure. The structural simplicity of this computationally inexpensive model allows us to clearly isolate the global effects of iron availability on maximum light-saturated photosynthesis rates from those of photosynthetic efficiency. We find that the effect on light-saturated photosynthesis rates is dominant, negating the importance of photosynthetic efficiency in most regions, especially the cold waters of the Southern Ocean. The primary exceptions to this occur in iron-rich regions of the Northern Hemisphere, where high light-saturated photosynthesis rates cause photosynthetic efficiency to play a more important role. Additionally, we speculate that the small phytoplankton dominating iron-limited regions tend to have relatively high photosynthetic efficiency, such that iron-limitation has less of a deleterious effect on growth rates than would be expected from short-term iron addition experiments.

Angiogram, fundus, and oxygen saturation optic nerve head image fusion

NASA Astrophysics Data System (ADS)

Cao, Hua; Khoobehi, Bahram

2009-02-01

A novel multi-modality optic nerve head image fusion approach has been successfully designed. The new approach has been applied on three ophthalmologic modalities: angiogram, fundus, and oxygen saturation retinal optic nerve head images. It has achieved an excellent result by giving the visualization of fundus or oxygen saturation images with a complete angiogram overlay. During this study, two contributions have been made in terms of novelty, efficiency, and accuracy. The first contribution is the automated control point detection algorithm for multi-sensor images. The new method employs retina vasculature and bifurcation features by identifying the initial good-guess of control points using the Adaptive Exploratory Algorithm. The second contribution is the heuristic optimization fusion algorithm. In order to maximize the objective function (Mutual-Pixel-Count), the iteration algorithm adjusts the initial guess of the control points at the sub-pixel level. A refinement of the parameter set is obtained at the end of each loop, and finally an optimal fused image is generated at the end of the iteration. It is the first time that Mutual-Pixel-Count concept has been introduced into biomedical image fusion area. By locking the images in one place, the fused image allows ophthalmologists to match the same eye over time and get a sense of disease progress and pinpoint surgical tools. The new algorithm can be easily expanded to human or animals' 3D eye, brain, or body image registration and fusion.

Simulation and experimental characterization of the point spread function, pixel saturation, and blooming of a mercury cadmium telluride focal plane array.

PubMed

Soehnel, Grant; Tanbakuchi, Anthony

2012-11-20

A custom IR spot scanning experiment was constructed to project subpixel spots on a mercury cadmium telluride focal plane array (FPA). The hardware consists of an FPA in a liquid nitrogen cooled Dewar, high precision motorized stages, a custom aspheric lens, and a 1.55 and 3.39 μm laser source. By controlling the position and intensity of the spot, characterizations of cross talk, saturation, blooming, and (indirectly) the minority carrier lifetime were performed. In addition, a Monte-Carlo-based charge diffusion model was developed to validate experimental data and make predictions. Results show very good agreement between the model and experimental data. Parameters such as wavelength, reverse bias, and operating temperature were found to have little effect on pixel crosstalk in the absorber layer of the detector. Saturation characterizations show that these FPAs, which do not have antiblooming circuitry, exhibit an increase in cross talk due to blooming at ∼39% beyond the flux required for analog saturation.

Brain oxygen saturation assessment in neonates using T2-prepared blood imaging of oxygen saturation and near-infrared spectroscopy.

PubMed

Alderliesten, Thomas; De Vis, Jill B; Lemmers, Petra Ma; Hendrikse, Jeroen; Groenendaal, Floris; van Bel, Frank; Benders, Manon Jnl; Petersen, Esben T

2017-03-01

Although near-infrared spectroscopy is increasingly being used to monitor cerebral oxygenation in neonates, it has a limited penetration depth. The T 2 -prepared Blood Imaging of Oxygen Saturation (T 2 -BIOS) magnetic resonance sequence provides an oxygen saturation estimate on a voxel-by-voxel basis, without needing a respiratory calibration experiment. In 15 neonates, oxygen saturation measured by T 2 -prepared blood imaging of oxygen saturation and near-infrared spectroscopy were compared. In addition, these measures were compared to cerebral blood flow and venous oxygen saturation in the sagittal sinus. A strong linear relation was found between the oxygen saturation measured by magnetic resonance imaging and the oxygen saturation measured by near-infrared spectroscopy ( R 2  = 0.64, p < 0.001). Strong linear correlations were found between near-infrared spectroscopy oxygen saturation, and magnetic resonance imaging measures of frontal cerebral blood flow, whole brain cerebral blood flow and venous oxygen saturation in the sagittal sinus ( R 2  = 0.71, 0.50, 0.65; p < 0.01). The oxygen saturation obtained by T 2 -prepared blood imaging of oxygen saturation correlated with venous oxygen saturation in the sagittal sinus ( R 2  = 0.49, p = 0.023), but no significant correlations could be demonstrated with frontal and whole brain cerebral blood flow. These results suggest that measuring oxygen saturation by T 2 -prepared blood imaging of oxygen saturation is feasible, even in neonates. Strong correlations between the various methods work as a cross validation for near-infrared spectroscopy and T 2 -prepared blood imaging of oxygen saturation, confirming the validity of using of these techniques for determining cerebral oxygenation.

[Response of photosynthesis and growth to weak light regime in different Adzuki bean (Vigna angularis) varieties].

PubMed

Zou, Chang-ming; Wang, Yun-qing; Cao, Wei-dong; Liu, Ying; Zhang, Xiao-hong; Tang, Shan

2015-12-01

In order to determine the adaptability of Adzuki beans as the interplanting crops in fruit yards, field and pot experimental treatments with full natural light and weak light (48% of full natural light) regimes were conducted to test the shade tolerance and physiological responses of three Adzuki bean varieties including Funan green Vigna angularis (FGVA), early-mature black V. angularis (EBVA) and late-mature black V. angularis (LBVA). The leaf photosynthetic characteristic parameters, photosynthetic pigment contents and the activity of RuBPCase were measured during the first bloom stage. The response of growth to weak light was likewise studied. The results showed that the photosynthetic characteristic parameters, i.e., the maximum net photosynthetic rate, light saturation point and light compensation point of the three Adzuki bean varieties under the weak light stress changed differently. The weak light stress induced the reduction of net photosynthetic rate, water use efficiency and RuBPCase activity of the three Adzuki bean varieties significantly. The contents of chlorophyll a and chlorophyll b in leaves of FGVA increased significantly, while Chl a/b and carotenoid content in the leaves decreased significantly after shading. But the other two varieties did not change obviously in photosynthetic pigments content after shading. The weak light changed the growth of the three Adzuki bean varieties, such as decreasing dry matter yield and dry matter accumulation efficiency, reducing root nodule and root-shoot ratio, debasing leaves quantity and leaf area index. The first bloom stage and maturing stage of FGVA advanced, while that of EBVA delayed under weak light. However, flowers were not strong enough to seed for LBVA under the weak light. In conclusion, according to the photosynthetic characteristics changes after shading, as well as the growth status, we concluded that the shade tolerance of the three Adzuki beans was ranked as FGVA>EBVA>LBVA.

CsPbBr3 nanocrystal saturable absorber for mode-locking ytterbium fiber laser

NASA Astrophysics Data System (ADS)

Zhou, Yan; Hu, Zhiping; Li, Yue; Xu, Jianqiu; Tang, Xiaosheng; Tang, Yulong

2016-06-01

Cesium lead halide perovskite nanocrystals (CsPbX3, X = Cl, Br, I) have been reported as efficient light-harvesting and light-emitting semiconductor materials, but their nonlinear optical properties have been seldom touched upon. In this paper, we prepare layered CsPbBr3 nanocrystal films and characterize their physical properties. Broadband linear absorption from ˜0.8 to over 2.2 μm and nonlinear optical absorption at the 1-μm wavelength region are measured. The CsPbBr3 saturable absorber (SA), manufactured by drop-casting of colloidal CsPbBr3 liquid solution on a gold mirror, shows modulation depth and saturation intensity of 13.1% and 10.7 MW/cm2, respectively. With this SA, mode-locking operation of a polarization-maintained ytterbium fiber laser produces single pulses with duration of ˜216 ps, maximum average output power of 10.5 mW, and the laser spectrum is centered at ˜1076 nm. This work shows that CsPbBr3 films can be efficient SA candidates for fiber lasers and also have great potential to become broadband linear and nonlinear optical materials for photonics and optoelectronics.

Excess Diffuse Light Absorption in Upper Mesophyll Limits CO2 Drawdown and Depresses Photosynthesis.

PubMed

Earles, J Mason; Théroux-Rancourt, Guillaume; Gilbert, Matthew E; McElrone, Andrew J; Brodersen, Craig R

2017-06-01

In agricultural and natural systems, diffuse light can enhance plant primary productivity due to deeper penetration into and greater irradiance of the entire canopy. However, for individual sun-grown leaves from three species, photosynthesis is actually less efficient under diffuse compared with direct light. Despite its potential impact on canopy-level productivity, the mechanism for this leaf-level diffuse light photosynthetic depression effect is unknown. Here, we investigate if the spatial distribution of light absorption relative to electron transport capacity in sun- and shade-grown sunflower ( Helianthus annuus ) leaves underlies its previously observed diffuse light photosynthetic depression. Using a new one-dimensional porous medium finite element gas-exchange model parameterized with light absorption profiles, we found that weaker penetration of diffuse versus direct light into the mesophyll of sun-grown sunflower leaves led to a more heterogenous saturation of electron transport capacity and lowered its CO 2 concentration drawdown capacity in the intercellular airspace and chloroplast stroma. This decoupling of light availability from photosynthetic capacity under diffuse light is sufficient to generate an 11% decline in photosynthesis in sun-grown but not shade-grown leaves, primarily because thin shade-grown leaves similarly distribute diffuse and direct light throughout the mesophyll. Finally, we illustrate how diffuse light photosynthetic depression could overcome enhancement in canopies with low light extinction coefficients and/or leaf area, pointing toward a novel direction for future research. © 2017 American Society of Plant Biologists. All Rights Reserved.

Wave Velocities in Hydrocarbons and Hydrocarbon Saturated - Applications to Eor Monitoring.

NASA Astrophysics Data System (ADS)

Wang, Zhijing

In order to effectively utilize many new seismic technologies and interpret the results, acoustic properties of both reservoir fluids and rocks must be well understood. It is the main purpose of this dissertation to investigate acoustic wave velocities in different hydrocarbons and hydrocarbon saturated rocks under various reservoir conditions. The investigation consists of six laboratory experiments, followed by a series of theoretical and application analyses. All the experiments involve acoustic velocity measurements in hydrocarbons and rocks with different hydrocarbons, using the ultrasonic pulse-transmission methods, at elevated temperatures and pressures. In the experiments, wave velocities are measured versus both temperature and pressure in 50 hydrocarbons. The relations among the acoustic velocity, temperature, pressure, API gravity, and the molecular weight of the hydrocarbons are studied, and empirical equations are established which allow one to calculate the acoustic velocities in hydrocarbons with known API gravities. Wave velocities in hydrocarbon mixtures are related to the composition and the velocities in the components. The experimental results are also analyzed in terms of various existing theories and models of the liquid state. Wave velocities are also measured in various rocks saturated with different hydrocarbons. The compressional wave velocities in rocks saturated with pure hydrocarbons increase with increasing the carbon number of the hydrocarbons. They decrease markedly in all the heavy hydrocarbon saturated rocks as temperature increases. Such velocity decreases set the petrophysical basis for in-situ seismic monitoring thermal enhanced oil recovery processes. The effects of carbon dioxide flooding and different pore fluids on wave velocities in rocks are also investigated. It is highly possible that there exist reflections of seismic waves at the light-heavy oil saturation interfaces in-situ. It is also possible to use seismic methods

The Choroidal Eye Oximeter - An instrument for measuring oxygen saturation of choroidal blood in vivo

NASA Technical Reports Server (NTRS)

Laing, R. A.; Danisch, L. A.; Young, L. R.

1975-01-01

The Choroidal Eye Oximeter is an electro-optical instrument that noninvasively measures the oxygen saturation of choroidal blood in the back of the human eye by a spectrophotometric method. Since choroidal blood is characteristic of blood which is supplied to the brain, the Choroidal Eye Oximeter can be used to monitor the amount of oxygen which is supplied to the brain under varying external conditions. The instrument consists of two basic systems: the optical system and the electronic system. The optical system produces a suitable bi-chromatic beam of light, reflects this beam from the fundus of the subject's eye, and onto a low-noise photodetector. The electronic system amplifies the weak composite signal from the photodetector, computes the average oxygen saturation from the area of the fundus that was sampled, and displays the value of the computed oxygen saturation on a panel meter.

Changes in the composition and properties of Ashalchinskoye bitumen-saturated sandstones when exposed to water vapor

NASA Astrophysics Data System (ADS)

Korolev, E.; Eskin, A.; Kolchugin, A.; Morozov, V.; Khramchenkov, M.; Gabdelvalieva, R.

2018-05-01

Ashalchinskoye bitumen deposit is an experimental platform for testing technology of high-viscosity oil extraction from reservoir rocks. Last time for enhanced of oil recovery in reservoir used pressurization a water vapor with a temperature of ∼ 180 ° C (SAGD technology). However, what happens in sandstone reservoir is little known. We did a study of the effects of water vapor on the structural components of bitumen saturated sandstone. In paper were studied the rock samples at base condition and after one week exposure by water vapour. The thermal analysis showed that steaming helps to removes light and middle oil fractions with a boiling point up to 360 ° C from oil saturated sandstones. Content of heavy oil fractions virtually unchanged. Studying the composition of water extractions of samples showed that the process of aquathermolysis of oil is accompanied by a lowering of the pH of the pore solution from 7.4 to 6.5 and rise content in several times of mobile cations Ca2+, Mg2+ and HCO3 -, SO4 2- anions. Follows from this that the thermal steam effect by bitumen saturated sandstones leads to partial oxidation of hydrocarbons with to form a carbon dioxide. The source of sulfate ions were oxidized pyrite aggregates. Due to the increasing acidity of condensed water, which fills the pore space of samples, pore fluid becomes aggressive to calcite and dolomite cement of bitumen saturated sandstones. As a result of the dissolution of carbonate cement the pore fluid enriched by calcium and magnesium cations. Clearly, that the process is accompanied by reduction of contact strength between fragments of minerals and rocks. Resulting part of compounds is separated from the outer side of samples and falls to bottom of water vapor container. Decreasing the amount of calcite and dolomite anions in samples in a steam-treated influence is confirmed by X-Ray analysis. X-Ray analysis data of study adscititious component of rocks showed that when influenced of water vapor to

Up Scalable Full Colour Plasmonic Pixels with Controllable Hue, Brightness and Saturation.

PubMed

Mudachathi, Renilkumar; Tanaka, Takuo

2017-04-26

It has long been the interests of scientists to develop ink free colour printing technique using nano structured materials inspired by brilliant colours found in many creatures like butterflies and peacocks. Recently isolated metal nano structures exhibiting preferential light absorption and scattering have been explored as a promising candidate for this emerging field. Applying such structures in practical use, however, demands the production of individual colours with distinct reflective peaks, tunable across the visible wavelength region combined with controllable colour attributes and economically feasible fabrication. Herein, we present a simple yet efficient colour printing approach employing sub-micrometer scale plasmonic pixels of single constituent metal structure which supports near unity broadband light absorption at two distinct wavelengths, facilitating the creation of saturated colours. The dependence of these resonances on two different parameters of the same pixel enables controllable colour attributes such as hue, brightness and saturation across the visible spectrum. The linear dependence of colour attributes on the pixel parameters eases the automation; which combined with the use of inexpensive and stable aluminum as functional material will make this colour design strategy relevant for use in various commercial applications like printing micro images for security purposes, consumer product colouration and functionalized decoration to name a few.

Seasonal variability of light availability and utilization in the Sargasso Sea

NASA Technical Reports Server (NTRS)

Siegel, David A.; Michaels, Anthony F.; Sorensen, Jens C.; O'Brein, Margaret C.; Hammer, Melodie A.

1995-01-01

A 2 year time series of optical, biogeochemical, and physical parameters, taken near the island of Bermuda, is used to evaluate the sources of temporal variability in light avaliability and utilization in the Sargasso Sea. Integrated assessments of light availability are made by examining the depth of constant percent incident photosynthetically available radiation (% PAR) isolumes. To first order, changes in the depth %PAR isolumes were caused by physical processes: deep convection mixing in the winter which led to the spring bloom and concurrent shallowing of %PAR depths and the occurrence of anomalous thermohaline water masses during the summer and fall seasons. Spectral light availability variations are assessed using determinations of diffuse attenuation coefficient spectra which illustrates a significant seasonal cycle in colored detrital particulate and/or dissolved materials that is unrelated to changes in chlorophyll pigment concentrations. Temporal variations in the photosynthetic light utilization index Psi are used to assess vertically intergrated light utilization variations. Values of Psi are highly variable and show no apparent seasonal pattern which indicates that Psi is not simply a 'biogeochemical constant.' Determinations of in situ primary production rates and daily mean PAR fluxes are used to diagnose the relative role of light limitation in determining vertically integrated rates of primary production integral PP. The mean depth of the light-saturated zone (the vertical region where the daily mean PAR flux was greater than or equal to the saturation irradiance) is only approximately 40 m, although more than one half of interal PP occurred within this zone. Production model results illustrate that accurate predictions of integral PP are dependent upon rates of light-saturated production rather than upon indices of light limitation. It seems unlikely that significant improvements in simple primary production models will come from the

Predicting data saturation in qualitative surveys with mathematical models from ecological research.

PubMed

Tran, Viet-Thi; Porcher, Raphael; Tran, Viet-Chi; Ravaud, Philippe

2017-02-01

Sample size in surveys with open-ended questions relies on the principle of data saturation. Determining the point of data saturation is complex because researchers have information on only what they have found. The decision to stop data collection is solely dictated by the judgment and experience of researchers. In this article, we present how mathematical modeling may be used to describe and extrapolate the accumulation of themes during a study to help researchers determine the point of data saturation. The model considers a latent distribution of the probability of elicitation of all themes and infers the accumulation of themes as arising from a mixture of zero-truncated binomial distributions. We illustrate how the model could be used with data from a survey with open-ended questions on the burden of treatment involving 1,053 participants from 34 different countries and with various conditions. The performance of the model in predicting the number of themes to be found with the inclusion of new participants was investigated by Monte Carlo simulations. Then, we tested how the slope of the expected theme accumulation curve could be used as a stopping criterion for data collection in surveys with open-ended questions. By doubling the sample size after the inclusion of initial samples of 25 to 200 participants, the model reliably predicted the number of themes to be found. Mean estimation error ranged from 3% to 1% with simulated data and was <2% with data from the study of the burden of treatment. Sequentially calculating the slope of the expected theme accumulation curve for every five new participants included was a feasible approach to balance the benefits of including these new participants in the study. In our simulations, a stopping criterion based on a value of 0.05 for this slope allowed for identifying 97.5% of the themes while limiting the inclusion of participants eliciting nothing new in the study. Mathematical models adapted from ecological research

Effects of Hypothermic Cardiopulmonary Bypass on Internal Jugular Bulb Venous Oxygen Saturation, Cerebral Oxygen Saturation, and Bispectral Index in Pediatric Patients Undergoing Cardiac Surgery: A Prospective Study

PubMed Central

Hu, Zhiyong; Xu, Lili; Zhu, Zhirui; Seal, Robert; McQuillan, Patrick M.

2016-01-01

Abstract The objective of this study was to evaluate the effect of hypothermic cardiopulmonary bypass (CPB) on cerebral oxygen saturation (rSO2), internal jugular bulb venous oxygen saturation (SjvO2), mixed venous oxygen saturation (SvO2), and bispectral index (BIS) used to monitor cerebral oxygen balance in pediatric patients. Sixty American Society of Anesthesiologists Class II-III patients aged 1 to 4 years old with congenital heart disease scheduled for elective cardiac surgery were included in this study. Temperature, BIS, rSO2, mean arterial pressure, central venous pressure, cerebral perfusion pressure (CPP), and hematocrit were recorded. Internal jugular bulb venous oxygen saturation and SvO2 were obtained from blood gas analysis at the time points: after induction of anesthesia (T0), beginning of CPB (T1), ascending aortic occlusion (T2), 20 minutes after initiating CPB (T3), coronary reperfusion (T4), separation from CPB (T5), and at the end of operation (T6). The effect of hypothermia or changes in CPP on rSO2, SjvO2, SvO2, and BIS were analyzed. Compared with postinduction baseline values, rSO2 significantly decreased at all-time points: onset of extracorporeal circulation, ascending aortic occlusion, 20 minutes after CPB initiation, coronary reperfusion, and separation from CPB (P < 0.05). Compared with measurements made following induction of anesthesia, SjvO2 significantly increased with initiation of CPB, ascending aortic occlusion, 20 minutes after initiating CPB, coronary reperfusion, and separation from CPB (P < 0.05). Compared with induction of anesthesia, BIS significantly decreased with the onset of CPB, aortic cross clamping, 20 minutes after initiating CPB, and coronary reperfusion (P < 0.05). Bispectral index increased following separation from CPB. There was no significant change in SvO2 during cardiopulmonary bypass (P > 0.05). Correlation analysis demonstrated that rSO2 was positively related to CPP (r = 0.687, P�

Effects of hue, saturation, and brightness on preference: a study on Goethe's color circle with RGB color space

NASA Astrophysics Data System (ADS)

Camgoz, Nilgun; Yener, Cengiz

2002-06-01

In order to investigate preference responses for foreground- background color relationships, 85 university undergraduates in Ankara, Turkey, viewed 6 background colors (red, yellow, green, cyan, blue, and magenta) on which color squares of differing hues, saturations, and brightnesses were presented. All the background colors had maximum brightness (100%) and maximum saturation (100%). Subjects were asked to show the color square they preferred on the presented background color viewed through a computer monitor. The experimental setup consisted of a computer monitor located in a windowless room, illuminated with cove lighting. The findings of the experiment show that the brightness 100%- saturation 100% range is significantly preferred the most (p-value < 0.03). Thus, color squares that are most saturated and brightest are preferred on backgrounds of most saturated and brightest colors. Regardless of the background colors viewed, the subjects preferred blue the most (p-value < 0.01). Findings of the study are also discussed with pertinent research on the field. Through this analysis, an understanding of foreground-background color relationships in terms of preference is sought.

Interpreting HSE Contents of Planetary Basalts: The Importance of Sulfide Saturation and Under-Saturation

NASA Technical Reports Server (NTRS)

Righter, K.

2000-01-01

Highly siderophile elements provide important constraints on planetary differentiation due to their siderophile behavior. Their interpretation in terms of planetary differentiation models has so far overlooked the importance of sulfide saturation and under-saturation.

Effects of exogenous epibrassinolide on photosynthetic characteristics in tomato (Lycopersicon esculentum Mill) seedlings under weak light stress.

PubMed

Wang, Ming; Jiang, Weijie; Yu, Hongjun

2010-03-24

The effects of three concentrations (0.1, 0.01, 0.001 mg/kg) of exogenous 24-epibrassinolide on leaf photosynthesis, chlorophyll content, chlorophyll fluorescence, and parameters of light response curve in tomato seedlings under 150 micromol x m(-2) x s(-1) weak light stress were studied, with two tomato cultivars, 'Zhongza9', tolerant, and 'Zhongshu6', sensitive to weak light stress. The results showed that the net photosynthetic rate (Pn), maximal photochemical quantum efficiency of PSII (Fv/Fm), light saturation point (LSP), and dark respiration rate (Rd) decreased remarkably under weak light, but the chlorophyll content, especially chlorophyll b (chlb) content, increased obviously compared with normal light intensity control. However, exogenous 24-epibrassinolide alleviated the decrease of leaf Pn and Fv/Fm and induced the further increase of chlb content as well as the further decrease of Rd and chla/chlb under weak light stress, which indicated that exogenous 24-epibrassinolide could enhance plant tolerance to weak light and diminish damage from weak light. However, the optimum concentrations were different between the two cultivars; 0.1 mg/kg 24-epibrassinolide showed the best induction effects in 'Zhongshu6', and the best level for 'Zhongza9' was 0.01 mg/kg 24-epibrassinolide.

Discrete Snaking: Multiple Cavity Solitons in Saturable Media

NASA Astrophysics Data System (ADS)

Yulin, A. V.; Champneys, A. R.

2010-01-01

A one-dimensional lattice equation is studied that models the light field in an optical system comprised of a periodic array of optical cavities pumped by a coherent light source. The model includes effects of linear detuning, linear and nonlinear dissipation, and saturable nonlinearity. A wide variety of different parameter regions are studied in which there is bistability between low-power and high-power spatially homogeneous steady states. By posing the steady problem as a time-reversible four-dimensional discrete map, it is shown that temporal stability of these states is a necessary condition for the existence of spatially localized modes. Numerical path-following is used to find both so-called bright solitons (whose core is at a higher intensity than the tails) and grey solitons (with nonzero lower intensity tails), whose temporal stability is also computed. Starting from the case of focusing nonlinearity in the continuum limit and with energy conservation, the effects of dissipation and spatial discreteness are studied both separately and in combination. The presence of Maxwell points, where heteroclinic connections exist between different homogeneous states, is found to lead to snaking bifurcation diagrams where the width of the soliton grows via a process of successive increase and decrease of a parameter representing the pump strength. These structures are found to cause parameter intervals where there are infinitely many distinct stable solitons, both bright and grey. Mechanisms are revealed by which the snakes can be created and destroyed as a second parameter is varied. In particular, the bright solitons reach the boundary of the bistability region where the homogeneous state in the soliton's tail undergoes a fold, whereupon the snake splits into many separate loops. More complex mechanisms underlie the morphogenesis of the grey soliton branches, for example, due to a fold of the homogeneous state that forms the core of the snaking soliton. Further

Noninvasive measurement of internal jugular venous oxygen saturation by photoacoustic imaging

NASA Astrophysics Data System (ADS)

Garcia-Uribe, Alejandro; Erpelding, Todd N.; Ke, Haixin; Reddy, Kavya; Sharma, Anshuman; Wang, Lihong V.

2014-03-01

The metabolic rate and oxygen consumption of the brain is reflected in jugular venous oxygen saturation. In many clinical conditions, such as head trauma, stroke, and low cardiac output states, the brain is at risk for hypoxic-ischemic injury. The current gold standard for monitoring brain oxygenation is invasive and requires jugular vein catheterization under fluoroscopic guidance; and therefore it is rarely used. Photo-acoustic tomography in combination with ultrasound can be used to estimate oxygen saturation of the internal jugular vein in real-time. This noninvasive method will enable earlier detection and prevention of impending hypoxic brain injury. A wavelength-tunable dye laser pumped by a Nd:YAG laser delivers light through an optical fiber bundle, and a modified commercial ultrasound imaging system (Philips iU22) detects both the pulse-echo ultrasound (US) and photoacoustic (PA) signals. A custom-built multichannel data acquisition system renders co-registered ultrasound and photoacoustic images at 5 frames per second. After the jugular vein was localized in healthy volunteers, dualwavelength PA images were used to calculate the blood hemoglobin oxygen saturation from the internal jugular vein in vivo. The preliminary results raise confidence that this emerging technology can be used clinically as an accurate, noninvasive indicator of cerebral oxygenation.

Optimization measurement of muscle oxygen saturation under isometric studies using FNIRS

NASA Astrophysics Data System (ADS)

Halim, A. A. A.; Laili, M. H.; Salikin, M. S.; Rusop, M.

2018-05-01

Development of functional near infrared spectroscopy (fNIRS) technologies has advanced quantification signal using multiple wavelength and detector to investigate hemodynamic response in human muscle. These non-invasive technologies have been widely used to solve the propagation of light inside the tissues including the absorption, scattering coefficient and to quantify the oxygenation level of haemoglobin and myoglobin in human muscle. The goal of this paper is to optimize the measurement of muscle oxygen saturation during isometric exercise using functional near infrared spectroscopy (fNIRS). The experiment was carried out on 15 sedentary healthy male volunteers. All volunteers are required to perform an isometric exercise at three assessment of muscular fatigue's level on flexor digitalis (FDS) muscle in the human forearm using fNIRS. The slopes of the signals have been highlighted to evaluate the muscle oxygen saturation of regional muscle fatigue. As a result, oxygen saturation slope from 10% exercise showed steeper than the first assessment at 30%-50% of fatigues level. The hemodynamic signal response showed significant value (p=0.04) at all three assessment of muscular fatigue's level which produce a p-value (p<0.05) measured by fNIRS. Thus, this highlighted parameter could be used to estimate fatigue's level of human and could open other possibilities to study muscle performance diagnosis.

Generation of Polar Semi-Saturated Bicyclic Pyrazoles for Fragment-Based Drug Discovery Campaigns.

PubMed

Luise, Nicola; Wyatt, Paul

2018-05-07

Synthesising polar semi-saturated bicyclic heterocycles can lead to better starting points for fragment-based drug discovery (FBDD) programs. This communication highlights the application of diverse chemistry to construct bicyclic systems from a common intermediate, where pyrazole, a privileged heteroaromatic able to bind effectively to biological targets, is fused to diverse saturated counterparts. The generated fragments can be further developed either after confirmation of their binding pose or early in the process, as their synthetic intermediates. Essential quality control (QC) for selection of small molecules to add to a fragment library is discussed. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effective Porosity Measurements by Wet- and Dry-type Vacuum Saturations using Process-Programmable Vacuum Saturation System

NASA Astrophysics Data System (ADS)

Lee, T. J.; Lee, K. S., , Dr; Lee, S. K.

2017-12-01

One of the most important factors in measuring effective porosity by vacuum saturation method is that the air in the pore space can be fully substituted by water during the vacuum saturation process. International Society of Rock Mechanics (ISRM) suggests vacuuming a rock sample submerged in the water, while American Society of Test and Materials (ASTM) vacuuming the sample and water separately and then pour the water to the sample. In this study, we call the former wet-type vacuum saturation (WVS) method and the latter dry-type vacuum saturation (DVS) method, and compare the effective porosity measured by the two different vacuum saturation processes. For that purpose, a vacuum saturation system has been developed, which can support both WVS and DVS by only changing the process by programming. Comparison of effective porosity has been made for a cement mortar and rock samples. As a result, DVS can substitute more void volume to water than WVS, which in turn insists that DVS can provide more exact value of effective porosity than WVS.

Effects of saturation and contrast polarity on the figure-ground organization of color on gray.

PubMed

Dresp-Langley, Birgitta; Reeves, Adam

2014-01-01

Poorly saturated colors are closer to a pure gray than strongly saturated ones and, therefore, appear less "colorful."Color saturation is effectively manipulated in the visual arts for balancing conflicting sensations and moods and for inducing the perception of relative distance in the pictorial plane. While perceptual science has proven quite clearly that the luminance contrast of any hue acts as a self-sufficient cue to relative depth in visual images, the role of color saturation in such figure-ground organization has remained unclear. We presented configurations of colored inducers on gray "test" backgrounds to human observers. Luminance and saturation of the inducers was uniform on each trial, but varied across trials. We ran two separate experimental tasks. In the relative background brightness task, perceptual judgments indicated whether the apparent brightness of the gray test background contrasted with, assimilated to, or appeared equal (no effect) to that of a comparison background with the same luminance contrast. Contrast polarity and its interaction with color saturation affected response proportions for contrast, assimilation and no effect. In the figure-ground task, perceptual judgments indicated whether the inducers appeared to lie in front of, behind, or in the same depth with the background. Strongly saturated inducers produced significantly larger proportions of foreground effects indicating that these inducers stand out as figure against the background. Weakly saturated inducers produced significantly larger proportions of background effects, indicating that these inducers are perceived as lying behind the backgrounds. We infer that color saturation modulates figure-ground organization, both directly by determining relative inducer depth, and indirectly, and in interaction with contrast polarity, by affecting apparent background brightness. The results point toward a hitherto undocumented functional role of color saturation in the genesis of

Effects of saturation and contrast polarity on the figure-ground organization of color on gray

PubMed Central

Dresp-Langley, Birgitta; Reeves, Adam

2014-01-01

Poorly saturated colors are closer to a pure gray than strongly saturated ones and, therefore, appear less “colorful.”Color saturation is effectively manipulated in the visual arts for balancing conflicting sensations and moods and for inducing the perception of relative distance in the pictorial plane. While perceptual science has proven quite clearly that the luminance contrast of any hue acts as a self-sufficient cue to relative depth in visual images, the role of color saturation in such figure-ground organization has remained unclear. We presented configurations of colored inducers on gray “test” backgrounds to human observers. Luminance and saturation of the inducers was uniform on each trial, but varied across trials. We ran two separate experimental tasks. In the relative background brightness task, perceptual judgments indicated whether the apparent brightness of the gray test background contrasted with, assimilated to, or appeared equal (no effect) to that of a comparison background with the same luminance contrast. Contrast polarity and its interaction with color saturation affected response proportions for contrast, assimilation and no effect. In the figure-ground task, perceptual judgments indicated whether the inducers appeared to lie in front of, behind, or in the same depth with the background. Strongly saturated inducers produced significantly larger proportions of foreground effects indicating that these inducers stand out as figure against the background. Weakly saturated inducers produced significantly larger proportions of background effects, indicating that these inducers are perceived as lying behind the backgrounds. We infer that color saturation modulates figure-ground organization, both directly by determining relative inducer depth, and indirectly, and in interaction with contrast polarity, by affecting apparent background brightness. The results point toward a hitherto undocumented functional role of color saturation in the

A CMB foreground study in WMAP data: Extragalactic point sources and zodiacal light emission

NASA Astrophysics Data System (ADS)

Chen, Xi

The Cosmic Microwave Background (CMB) radiation is the remnant heat from the Big Bang. It serves as a primary tool to understand the global properties, content and evolution of the universe. Since 2001, NASA's Wilkinson Microwave Anisotropy Probe (WMAP) satellite has been napping the full sky anisotropy with unprecedented accuracy, precision and reliability. The CMB angular power spectrum calculated from the WMAP full sky maps not only enables accurate testing of cosmological models, but also places significant constraints on model parameters. The CMB signal in the WMAP sky maps is contaminated by microwave emission from the Milky Way and from extragalactic sources. Therefore, in order to use the maps reliably for cosmological studies, the foreground signals must be well understood and removed from the maps. This thesis focuses on the separation of two foreground contaminants from the WMAP maps: extragalactic point sources and zodiacal light emission. Extragalactic point sources constitute the most important foreground on small angular scales. Various methods have been applied to the WMAP single frequency maps to extract sources. However, due to the limited angular resolution of WMAP, it is possible to confuse positive CMB excursions with point sources or miss sources that are embedded in negative CMB fluctuations. We present a novel CMB-free source finding technique that utilizes the spectrum difference of point sources and CMB to form internal linear combinations of multifrequency maps to suppress the CMB and better reveal sources. When applied to the WMAP 41, 64 and 94 GHz maps, this technique has not only enabled detection of sources that are previously cataloged by independent methods, but also allowed disclosure of new sources. Without the noise contribution from the CMB, this method responds rapidly with the integration time. The number of detections varies as 0( t 0.72 in the two-band search and 0( t 0.70 in the three-band search from one year to five years

Cortical fMRI activation to opponents' body kinematics in sport-related anticipation: expert-novice differences with normal and point-light video.

PubMed

Wright, M J; Bishop, D T; Jackson, R C; Abernethy, B

2011-08-18

Badminton players of varying skill levels viewed normal and point-light video clips of opponents striking the shuttle towards the viewer; their task was to predict in which quadrant of the court the shuttle would land. In a whole-brain fMRI analysis we identified bilateral cortical networks sensitive to the anticipation task relative to control stimuli. This network is more extensive and localised than previously reported. Voxel clusters responding more strongly in experts than novices were associated with all task-sensitive areas, whereas voxels responding more strongly in novices were found outside these areas. Task-sensitive areas for normal and point-light video were very similar, whereas early visual areas responded differentially, indicating the primacy of kinematic information for sport-related anticipation. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

A technique for measuring oxygen saturation in biological tissues based on diffuse optical spectroscopy

NASA Astrophysics Data System (ADS)

Kleshnin, Mikhail; Orlova, Anna; Kirillin, Mikhail; Golubiatnikov, German; Turchin, Ilya

2017-07-01

A new approach to optical measuring blood oxygen saturation was developed and implemented. This technique is based on an original three-stage algorithm for reconstructing the relative concentration of biological chromophores (hemoglobin, water, lipids) from the measured spectra of diffusely scattered light at different distances from the probing radiation source. The numerical experiments and approbation of the proposed technique on a biological phantom have shown the high reconstruction accuracy and the possibility of correct calculation of hemoglobin oxygenation in the presence of additive noise and calibration errors. The obtained results of animal studies have agreed with the previously published results of other research groups and demonstrated the possibility to apply the developed technique to monitor oxygen saturation in tumor tissue.

Saturated fat, carbohydrate, and cardiovascular disease.

PubMed

Siri-Tarino, Patty W; Sun, Qi; Hu, Frank B; Krauss, Ronald M

2010-03-01

A focus of dietary recommendations for cardiovascular disease (CVD) prevention and treatment has been a reduction in saturated fat intake, primarily as a means of lowering LDL-cholesterol concentrations. However, the evidence that supports a reduction in saturated fat intake must be evaluated in the context of replacement by other macronutrients. Clinical trials that replaced saturated fat with polyunsaturated fat have generally shown a reduction in CVD events, although several studies showed no effects. An independent association of saturated fat intake with CVD risk has not been consistently shown in prospective epidemiologic studies, although some have provided evidence of an increased risk in young individuals and in women. Replacement of saturated fat by polyunsaturated or monounsaturated fat lowers both LDL and HDL cholesterol. However, replacement with a higher carbohydrate intake, particularly refined carbohydrate, can exacerbate the atherogenic dyslipidemia associated with insulin resistance and obesity that includes increased triglycerides, small LDL particles, and reduced HDL cholesterol. In summary, although substitution of dietary polyunsaturated fat for saturated fat has been shown to lower CVD risk, there are few epidemiologic or clinical trial data to support a benefit of replacing saturated fat with carbohydrate. Furthermore, particularly given the differential effects of dietary saturated fats and carbohydrates on concentrations of larger and smaller LDL particles, respectively, dietary efforts to improve the increasing burden of CVD risk associated with atherogenic dyslipidemia should primarily emphasize the limitation of refined carbohydrate intakes and a reduction in excess adiposity.

Benefits of Oxygen Saturation Targeting Trials: Oximeter Calibration Software Revision and Infant Saturations.

PubMed

Whyte, Robin K; Nelson, Harvey; Roberts, Robin S; Schmidt, Barbara

2017-03-01

It has been reported in the 3 Benefits of Oxygen Saturation Targeting (BOOST-II) trials that changes in oximeter calibration software resulted in clearer separation between the oxygen saturations in the two trial target groups. A revised analysis of the published BOOST-II data does not support this conclusion. Copyright © 2016 Elsevier Inc. All rights reserved.

Low-Light Image Enhancement Using Adaptive Digital Pixel Binning

PubMed Central

Yoo, Yoonjong; Im, Jaehyun; Paik, Joonki

2015-01-01

This paper presents an image enhancement algorithm for low-light scenes in an environment with insufficient illumination. Simple amplification of intensity exhibits various undesired artifacts: noise amplification, intensity saturation, and loss of resolution. In order to enhance low-light images without undesired artifacts, a novel digital binning algorithm is proposed that considers brightness, context, noise level, and anti-saturation of a local region in the image. The proposed algorithm does not require any modification of the image sensor or additional frame-memory; it needs only two line-memories in the image signal processor (ISP). Since the proposed algorithm does not use an iterative computation, it can be easily embedded in an existing digital camera ISP pipeline containing a high-resolution image sensor. PMID:26121609

33 CFR 80.155 - Watch Hill, RI to Montauk Point, NY.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Montauk Point, NY. (a) A line drawn from Watch Hill Light to East Point on Fishers Island. (b) A line drawn from Race Point to Race Rock Light; thence to Little Gull Island Light thence to East Point on Plum Island. (c) A line drawn from Plum Island Harbor East Dolphin Light to Plum Island Harbor West...

2. Southern Light Tower and Northern Light Tower, view north, ...

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

2. Southern Light Tower and Northern Light Tower, view north, south sides - Kennebec River Light Station, South side of Doubling Point Road, off State Highway 127, 1.8 miles south of U.S. Route 1, Arrowsic, Sagadahoc County, ME

Excess Diffuse Light Absorption in Upper Mesophyll Limits CO2 Drawdown and Depresses Photosynthesis1[OPEN

PubMed Central

Gilbert, Matthew E.; McElrone, Andrew J.

2017-01-01

In agricultural and natural systems, diffuse light can enhance plant primary productivity due to deeper penetration into and greater irradiance of the entire canopy. However, for individual sun-grown leaves from three species, photosynthesis is actually less efficient under diffuse compared with direct light. Despite its potential impact on canopy-level productivity, the mechanism for this leaf-level diffuse light photosynthetic depression effect is unknown. Here, we investigate if the spatial distribution of light absorption relative to electron transport capacity in sun- and shade-grown sunflower (Helianthus annuus) leaves underlies its previously observed diffuse light photosynthetic depression. Using a new one-dimensional porous medium finite element gas-exchange model parameterized with light absorption profiles, we found that weaker penetration of diffuse versus direct light into the mesophyll of sun-grown sunflower leaves led to a more heterogenous saturation of electron transport capacity and lowered its CO2 concentration drawdown capacity in the intercellular airspace and chloroplast stroma. This decoupling of light availability from photosynthetic capacity under diffuse light is sufficient to generate an 11% decline in photosynthesis in sun-grown but not shade-grown leaves, primarily because thin shade-grown leaves similarly distribute diffuse and direct light throughout the mesophyll. Finally, we illustrate how diffuse light photosynthetic depression could overcome enhancement in canopies with low light extinction coefficients and/or leaf area, pointing toward a novel direction for future research. PMID:28432257

Technical insight on the requirements for CO2-saturated growth of microalgae in photobioreactors.

PubMed

Yuvraj; Padmanabhan, Padmini

2017-06-01

Microalgal cultures are usually sparged with CO 2 -enriched air to preclude CO 2 limitation during photoautotrophic growth. However, the CO 2 vol% specifically required at operating conditions to meet the carbon requirement of algal cells in photobioreactor is never determined and 1-10% v/v CO 2 -enriched air is arbitrarily used. A scheme is proposed and experimentally validated for Chlorella vulgaris that allows computing CO 2 -saturated growth feasible at given CO 2 vol% and volumetric O 2 mass-transfer coefficient (k L a) O . CO 2 sufficiency in an experiment can be theoretically established to adjust conditions for CO 2 -saturated growth. The methodology completely eliminates the requirement of CO 2 electrode for online estimation of dissolved CO 2 to determine critical CO 2 concentration (C crit ), specific CO 2 uptake rate (SCUR), and volumetric CO 2 mass-transfer coefficient (k L a) C required for the governing CO 2 mass-transfer equation. C crit was estimated from specific O 2 production rate (SOPR) measurements at different dissolved CO 2 concentrations. SCUR was calculated from SOPR and photosynthetic quotient (PQ) determined from the balanced stoichiometric equation of growth. Effect of light attenuation and nutrient depletion on biomass estimate is also discussed. Furthermore, a simple design of photosynthetic activity measurement system was used, which minimizes light attenuation by hanging a low depth (ca. 10 mm) culture over the light source.

Self isolating high frequency saturable reactor

DOEpatents

Moore, James A.

1998-06-23

The present invention discloses a saturable reactor and a method for decoupling the interwinding capacitance from the frequency limitations of the reactor so that the equivalent electrical circuit of the saturable reactor comprises a variable inductor. The saturable reactor comprises a plurality of physically symmetrical magnetic cores with closed loop magnetic paths and a novel method of wiring a control winding and a RF winding. The present invention additionally discloses a matching network and method for matching the impedances of a RF generator to a load. The matching network comprises a matching transformer and a saturable reactor.

Finger blood content, light transmission, and pulse oximetry errors.

PubMed

Craft, T M; Lawson, R A; Young, J D

1992-01-01

The changes in light emitting diode current necessary to maintain a constant level of light incident upon a photodetector were measured in 20 volunteers at the two wavelengths employed by pulse oximeters. Three states of finger blood content were assessed; exsanguinated, hyperaemic, and normal. The changes in light emitting diode current with changes in finger blood content were small and are not thought to represent a significant source of error in saturation as measured by pulse oximetry.

HyspIRI High-Temperature Saturation Study

NASA Technical Reports Server (NTRS)

Realmuto, V.; Hook, S.; Foote, M.; Csiszar, I.; Dennison, P.; Giglio, L.; Ramsey, M.; Vaughan, R.G.; Wooster, M.; Wright, R.

2011-01-01

As part of the precursor activities for the HyspIRI mission, a small team was assembled to determine the optimum saturation level for the mid-infrared (4-?m) channel, which is dedicated to the measurement of hot targets. Examples of hot targets include wildland fires and active lava flows. This determination took into account both the temperature expected for the natural phenomena and the expected performance of the mid-infrared channel as well as its overlap with the other channels in the thermal infrared (7.5-12 ?m) designed to measure the temperature of lower temperature targets. Based on this work, the hot target saturation group recommends a saturation temperature of 1200 K for the mid-infrared channel. The saturation temperature of 1200 K represents a good compromise between the prevention of saturation and sensitivity to ambient temperature.

Structural color printing based on plasmonic metasurfaces of perfect light absorption

PubMed Central

Cheng, Fei; Gao, Jie; Luk, Ting S.; Yang, Xiaodong

2015-01-01

Subwavelength structural color filtering and printing technologies employing plasmonic nanostructures have recently been recognized as an important and beneficial complement to the traditional colorant-based pigmentation. However, the color saturation, brightness and incident angle tolerance of structural color printing need to be improved to meet the application requirement. Here we demonstrate a structural color printing method based on plasmonic metasurfaces of perfect light absorption to improve color performances such as saturation and brightness. Thin-layer perfect absorbers with periodic hole arrays are designed at visible frequencies and the absorption peaks are tuned by simply adjusting the hole size and periodicity. Near perfect light absorption with high quality factors are obtained to realize high-resolution, angle-insensitive plasmonic color printing with high color saturation and brightness. Moreover, the fabricated metasurfaces can be protected with a protective coating for ambient use without degrading performances. The demonstrated structural color printing platform offers great potential for applications ranging from security marking to information storage. PMID:26047486

Structural color printing based on plasmonic metasurfaces of perfect light absorption

DOE PAGES

Cheng, Fei; Gao, Jie; Luk, Ting S.; ...

2015-06-05

Subwavelength structural color filtering and printing technologies employing plasmonic nanostructures have recently been recognized as an important and beneficial complement to the traditional colorant-based pigmentation. However, the color saturation, brightness and incident angle tolerance of structural color printing need to be improved to meet the application requirement. Here we demonstrate a structural color printing method based on plasmonic metasurfaces of perfect light absorption to improve color performances such as saturation and brightness. Thin-layer perfect absorbers with periodic hole arrays are designed at visible frequencies and the absorption peaks are tuned by simply adjusting the hole size and periodicity. Near perfectmore » light absorption with high quality factors are obtained to realize high-resolution, angle-insensitive plasmonic color printing with high color saturation and brightness. Moreover, the fabricated metasurfaces can be protected with a protective coating for ambient use without degrading performances. The demonstrated structural color printing platform offers great potential for applications ranging from security marking to information storage.« less

Design of a visible-light spectroscopy clinical tissue oximeter.

PubMed

Benaron, David A; Parachikov, Ilian H; Cheong, Wai-Fung; Friedland, Shai; Rubinsky, Boris E; Otten, David M; Liu, Frank W H; Levinson, Carl J; Murphy, Aileen L; Price, John W; Talmi, Yair; Weersing, James P; Duckworth, Joshua L; Hörchner, Uwe B; Kermit, Eben L

2005-01-01

We develop a clinical visible-light spectroscopy (VLS) tissue oximeter. Unlike currently approved near-infrared spectroscopy (NIRS) or pulse oximetry (SpO2%), VLS relies on locally absorbed, shallow-penetrating visible light (475 to 625 nm) for the monitoring of microvascular hemoglobin oxygen saturation (StO2%), allowing incorporation into therapeutic catheters and probes. A range of probes is developed, including noncontact wands, invasive catheters, and penetrating needles with injection ports. Data are collected from: 1. probes, standards, and reference solutions to optimize each component; 2. ex vivo hemoglobin solutions analyzed for StO2% and pO2 during deoxygenation; and 3. human subject skin and mucosal tissue surfaces. Results show that differential VLS allows extraction of features and minimization of scattering effects, in vitro VLS oximetry reproduces the expected sigmoid hemoglobin binding curve, and in vivo VLS spectroscopy of human tissue allows for real-time monitoring (e.g., gastrointestinal mucosal saturation 69+/-4%, n=804; gastrointestinal tumor saturation 45+/-23%, n=14; and p<0.0001), with reproducible values and small standard deviations (SDs) in normal tissues. FDA approved VLS systems began shipping earlier this year. We conclude that VLS is suitable for the real-time collection of spectroscopic and oximetric data from human tissues, and that a VLS oximeter has application to the monitoring of localized subsurface hemoglobin oxygen saturation in the microvascular tissue spaces of human subjects.

Assessing species saturation: conceptual and methodological challenges.

PubMed

Olivares, Ingrid; Karger, Dirk N; Kessler, Michael

2018-05-07

Is there a maximum number of species that can coexist? Intuitively, we assume an upper limit to the number of species in a given assemblage, or that a lineage can produce, but defining and testing this limit has proven problematic. Herein, we first outline seven general challenges of studies on species saturation, most of which are independent of the actual method used to assess saturation. Among these are the challenge of defining saturation conceptually and operationally, the importance of setting an appropriate referential system, and the need to discriminate among patterns, processes and mechanisms. Second, we list and discuss the methodological approaches that have been used to study species saturation. These approaches vary in time and spatial scales, and in the variables and assumptions needed to assess saturation. We argue that assessing species saturation is possible, but that many studies conducted to date have conceptual and methodological flaws that prevent us from currently attaining a good idea of the occurrence of species saturation. © 2018 Cambridge Philosophical Society.

Response of Partially Saturated Non-cohesive Soils

NASA Astrophysics Data System (ADS)

Świdziński, Waldemar; Mierczyński, Jacek; Mikos, Agata

2017-12-01

This paper analyses and discusses experimental results of undrained triaxial tests. The tests were performed on non-cohesive partially saturated soil samples subjected to monotonic and cyclic loading. The tests were aimed at determining the influence of saturation degree on soil's undrained response (shear strength, excess pore pressure generation). The saturation of samples was monitored by checking Skempton's parameter B. Additionally, seismic P-wave velocity measurements were carried out on samples characterized by various degrees of saturation. The tests clearly showed that liquefaction may also take place in non-cohesive soils that are not fully saturated and that the liquefaction potential of such soils strongly depends on the B parameter.

Landsliding in partially saturated materials

USGS Publications Warehouse

Godt, J.W.; Baum, R.L.; Lu, N.

2009-01-01

[1] Rainfall-induced landslides are pervasive in hillslope environments around the world and among the most costly and deadly natural hazards. However, capturing their occurrence with scientific instrumentation in a natural setting is extremely rare. The prevailing thinking on landslide initiation, particularly for those landslides that occur under intense precipitation, is that the failure surface is saturated and has positive pore-water pressures acting on it. Most analytic methods used for landslide hazard assessment are based on the above perception and assume that the failure surface is located beneath a water table. By monitoring the pore water and soil suction response to rainfall, we observed shallow landslide occurrence under partially saturated conditions for the first time in a natural setting. We show that the partially saturated shallow landslide at this site is predictable using measured soil suction and water content and a novel unified effective stress concept for partially saturated earth materials. Copyright 2009 by the American Geophysical Union.

[Primary study on photosynthetic characteristics of Dendrobium nobile].

PubMed

Su, Wenhua; Zhang, Guangfei

2003-03-01

With LiCor-6400 Portable Photosynthesis System, carbon dioxide exchange pattern for leaves of Dendrobium nobile during 24 hours were studied in sunny day and rainy day, and the variation of CO2 exchange rate to light intensity was analysed. The results showed that in sunny day D. nobile absorbed CO2 in all day except at midday, at noon photorespiration took place. The CO2 exchange pattern was similar to Crassulacean Acid Metabolism(CAM). In rainy day CO2 uptake was in all day, at night CO2 uptake was monitored at 21:00, then CO2 released from 23:00 to dawn. Light saturation point was 1000 mumol/m2s. Over light saturation point photosynthesis, photoinhibition of photosynthesis will be induced by high-light. Exposed to high-light, the light saturation point and the CO2 uptake velocity would be decreased. With variation of environmental factors, photosynthetic pathway in D. nobile could change from CAM to C3 photosynthetic metabolism. It may be one of main reasons for D. nobile to adapt to the shade-requiring environment, the slow growth and rareness in nature.

Optical noninvasive calculation of hemoglobin components concentrations and fractional oxygen saturation using a ring-scattering pulse oximeter

NASA Astrophysics Data System (ADS)

Abdallah, Omar; Stork, Wilhelm; Muller-Glaser, Klaus

2004-06-01

The deficiencies of the currently used pulse oximeter are discussed in diverse literature. A hazardous pitfalls of this method is that the pulse oximeter will not detect carboxyhemoglobin (COHb) and methemoglobin (metHb) concentrations. This leads to incorrect measurement of oxygen saturation by carbon monoxide poisoning and methemoglobinemia. Also the total hemoglobin concentration will not be considered and can only be measured in-vitro up to now. A second pitfall of the standard pulse oximetry is that it will not be able to show a result by low perfusion of tissues. This case is available inter alia when the patient is under shock or has a low blood pressure. The new non-invasive system we designed measures the actual (fractional) oxygen saturation and hemoglobin concentration. It will enable us also to measure COHb and metHb. The measurement can be applied at better perfused body central parts. Four or more light emitting diodes (LEDs) or laser diodes (LDs) and five photodiodes (PDs) are used. The reflected light signal detected by photodiodes is processed using a modified Lambert-Beer law (I=I0×e-α.d ). According to this law, when a non scattering probe is irradiated with light having the incident intensity I0, the intensity of transmitted light I decays exponentially with the absorption coefficient a of that probe and its thickness d. Modifications of this law have been performed following the theoretical developed models in literature, Monte Carlo simulation and experimental measurement.

Power flow control using distributed saturable reactors

DOEpatents

Dimitrovski, Aleksandar D.

2016-02-13

A magnetic amplifier includes a saturable core having a plurality of legs. Control windings wound around separate legs are spaced apart from each other and connected in series in an anti-symmetric relation. The control windings are configured in such a way that a biasing magnetic flux arising from a control current flowing through one of the plurality of control windings is substantially equal to the biasing magnetic flux flowing into a second of the plurality of control windings. The flow of the control current through each of the plurality of control windings changes the reactance of the saturable core reactor by driving those portions of the saturable core that convey the biasing magnetic flux in the saturable core into saturation. The phasing of the control winding limits a voltage induced in the plurality of control windings caused by a magnetic flux passing around a portion of the saturable core.

Matrix product density operators: Renormalization fixed points and boundary theories

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

Cirac, J.I.; Pérez-García, D., E-mail: dperezga@ucm.es; ICMAT, Nicolas Cabrera, Campus de Cantoblanco, 28049 Madrid

We consider the tensors generating matrix product states and density operators in a spin chain. For pure states, we revise the renormalization procedure introduced in (Verstraete et al., 2005) and characterize the tensors corresponding to the fixed points. We relate them to the states possessing zero correlation length, saturation of the area law, as well as to those which generate ground states of local and commuting Hamiltonians. For mixed states, we introduce the concept of renormalization fixed points and characterize the corresponding tensors. We also relate them to concepts like finite correlation length, saturation of the area law, as well asmore » to those which generate Gibbs states of local and commuting Hamiltonians. One of the main result of this work is that the resulting fixed points can be associated to the boundary theories of two-dimensional topological states, through the bulk-boundary correspondence introduced in (Cirac et al., 2011).« less

Ghost imaging with bucket detection and point detection

NASA Astrophysics Data System (ADS)

Zhang, De-Jian; Yin, Rao; Wang, Tong-Biao; Liao, Qing-Hua; Li, Hong-Guo; Liao, Qinghong; Liu, Jiang-Tao

2018-04-01

We experimentally investigate ghost imaging with bucket detection and point detection in which three types of illuminating sources are applied: (a) pseudo-thermal light source; (b) amplitude modulated true thermal light source; (c) amplitude modulated laser source. Experimental results show that the quality of ghost images reconstructed with true thermal light or laser beam is insensitive to the usage of bucket or point detector, however, the quality of ghost images reconstructed with pseudo-thermal light in bucket detector case is better than that in point detector case. Our theoretical analysis shows that the reason for this is due to the first order transverse coherence of the illuminating source.

CsPbBr{sub 3} nanocrystal saturable absorber for mode-locking ytterbium fiber laser

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

Zhou, Yan; Li, Yue; Xu, Jianqiu

Cesium lead halide perovskite nanocrystals (CsPbX{sub 3}, X = Cl, Br, I) have been reported as efficient light-harvesting and light-emitting semiconductor materials, but their nonlinear optical properties have been seldom touched upon. In this paper, we prepare layered CsPbBr{sub 3} nanocrystal films and characterize their physical properties. Broadband linear absorption from ∼0.8 to over 2.2 μm and nonlinear optical absorption at the 1-μm wavelength region are measured. The CsPbBr{sub 3} saturable absorber (SA), manufactured by drop-casting of colloidal CsPbBr{sub 3} liquid solution on a gold mirror, shows modulation depth and saturation intensity of 13.1% and 10.7 MW/cm{sup 2}, respectively. With this SA, mode-locking operationmore » of a polarization-maintained ytterbium fiber laser produces single pulses with duration of ∼216 ps, maximum average output power of 10.5 mW, and the laser spectrum is centered at ∼1076 nm. This work shows that CsPbBr{sub 3} films can be efficient SA candidates for fiber lasers and also have great potential to become broadband linear and nonlinear optical materials for photonics and optoelectronics.« less

Efficient graphene saturable absorbers on D-shaped optical fiber for ultrashort pulse generation

PubMed Central

Zapata, J. D.; Steinberg, D.; Saito, L. A. M.; de Oliveira, R. E. P.; Cárdenas, A. M.; de Souza, E. A. Thoroh

2016-01-01

We demonstrated a method to construct high efficiency saturable absorbers based on the evanescent light field interaction of CVD monolayer graphene deposited on side-polished D-shaped optical fiber. A set of samples was fabricated with two different core-graphene distances (0 and 1 μm), covered with graphene ranging between 10 and 25 mm length. The mode-locking was achieved and the best pulse duration was 256 fs, the shortest pulse reported in the literature with CVD monolayer graphene in EDFL. As result, we find a criterion between the polarization relative extinction ratio in the samples and the pulse duration, which relates the better mode-locking performance with the higher polarization extinction ratio of the samples. This criterion also provides a better understanding of the graphene distributed saturable absorbers and their reproducible performance as optoelectronic devices for optical applications. PMID:26856886

Physics of the saturation of particle acceleration in relativistic magnetic reconnection

NASA Astrophysics Data System (ADS)

Kagan, Daniel; Nakar, Ehud; Piran, Tsvi

2018-05-01

We investigate the saturation of particle acceleration in relativistic reconnection using two-dimensional particle-in-cell simulations at various magnetizations σ. We find that the particle energy spectrum produced in reconnection quickly saturates as a hard power law that cuts off at γ ≈ 4σ, confirming previous work. Using particle tracing, we find that particle acceleration by the reconnection electric field in X-points determines the shape of the particle energy spectrum. By analysing the current sheet structure, we show that physical cause of saturation is the spontaneous formation of secondary magnetic islands that can disrupt particle acceleration. By comparing the size of acceleration regions to the typical distance between disruptive islands, we show that the maximum Lorentz factor produced in reconnection is γ ≈ 5σ, which is very close to what we find in our particle energy spectra. We also show that the dynamic range in Lorentz factor of the power-law spectrum in reconnection is ≤40. The hardness of the power law combined with its narrow dynamic range implies that relativistic reconnection is capable of producing the hard narrow-band flares observed in the Crab nebula but has difficulty producing the softer broad-band prompt gamma-ray burst emission.

Effects of target and distractor saturations on the cognitive performance of an integrated display interface

NASA Astrophysics Data System (ADS)

Xue, Chengqi; Li, Jing; Wang, Haiyan; Niu, Yafeng

2015-01-01

Color coding is often used to enhance decision quality in complex man-machine interfaces of integrated display systems. However, people are easily distracted by irrelevant colors and by the numerous data points and complex structures in the interface. Although an increasing number of studies are seriously focusing on the problem of achieving efficient color coding, few are able to determine the effects of target and distractor saturations on cognitive performance. To study the performances of target colors among distractors, a systematic experiment is conducted to assess the influence of high and low saturated targets on cognitive performance, and the affecting extent of different saturated distractors of homogeneous colors on targets. According to the analysis of the reaction time through the non-parametric statistical method, a calculation method of the cognitive performance of each color is proposed. Based on the calculation of the color differences and the accumulation of the reaction times, it is shown that with the different saturated distractors of homogeneous colors, the high saturated yellow targets perform better than the low saturated ones, and the green and blue targets have moderate performances. When searching for a singleton target placed on a black background, the color difference between the target and the distractor should be more than 20Δ E*ab units in the yellow saturation coding, whereas the color difference should be more than 40Δ E*ab units in the blue and green saturation coding. In addition, as regards saturation coding, the influence of the color difference between the target and the background on cognitive performance is greater than that of the color difference between the target and the distractor. Seemingly, the hue attribute determines whether the saturation difference between the target and the distractor affects the cognitive performance. Based on the experimental results, the simulation design of the instrument dials in a flight

Light extraction block with curved surface

DOEpatents

Levermore, Peter; Krall, Emory; Silvernail, Jeffrey; Rajan, Kamala; Brown, Julia J.

2016-03-22

Light extraction blocks, and OLED lighting panels using light extraction blocks, are described, in which the light extraction blocks include various curved shapes that provide improved light extraction properties compared to parallel emissive surface, and a thinner form factor and better light extraction than a hemisphere. Lighting systems described herein may include a light source with an OLED panel. A light extraction block with a three-dimensional light emitting surface may be optically coupled to the light source. The three-dimensional light emitting surface of the block may includes a substantially curved surface, with further characteristics related to the curvature of the surface at given points. A first radius of curvature corresponding to a maximum principal curvature k.sub.1 at a point p on the substantially curved surface may be greater than a maximum height of the light extraction block. A maximum height of the light extraction block may be less than 50% of a maximum width of the light extraction block. Surfaces with cross sections made up of line segments and inflection points may also be fit to approximated curves for calculating the radius of curvature.

Minority-carrier lifetime in InP as a function of light bias

NASA Technical Reports Server (NTRS)

Yater, Jane A.; Weinberg, I.; Jenkins, Phillip P.; Landis, Geoffrey A.

1995-01-01

Minority-carrier lifetime in InP is studied as a function of doping level and laser intensity using time-resolved photoluminescence. A continuous wave diode laser illuminates bulk InP and acts as a light bias, injecting a steady-state concentration of carriers. A 200 ps laser pulse produces a small transient signal on top of the steady-state luminescence, allowing lifetime to be measured directly as a function of incident intensity. For p-InP, lifetime increases with light bias up to a maximum value. Bulk recombination centers are presumably filled to saturation, allowing minority carriers to live longer. The saturation bias scales with dopant concentration for a particular dopant species. As light bias is increased for n-InP, minority-carrier lifetime increases slightly but then decreases, suggesting radiative recombination as a dominant decay mechanism.

All-fiber Yb-doped fiber laser passively mode-locking by monolayer MoS2 saturable absorber

NASA Astrophysics Data System (ADS)

Zhang, Yue; Zhu, Jianqi; Li, Pingxue; Wang, Xiaoxiao; Yu, Hua; Xiao, Kun; Li, Chunyong; Zhang, Guangyu

2018-04-01

We report on an all-fiber passively mode-locked ytterbium-doped (Yb-doped) fiber laser with monolayer molybdenum disulfide (ML-MoS2) saturable absorber (SA) by three-temperature zone chemical vapor deposition (CVD) method. The modulation depth, saturation fluence, and non-saturable loss of this ML-MoS2 are measured to be 3.6%, 204.8 μJ/cm2 and 6.3%, respectively. Based on this ML-MoS2SA, a passively mode-locked Yb-doped fiber laser has been achieved at 979 nm with pulse duration of 13 ps and repetition rate of 16.51 MHz. A mode-locked fiber laser at 1037 nm is also realized with a pulse duration of 475 ps and repetition rate of 26.5 MHz. To the best of our knowledge, this is the first report that the ML-MoS2 SA is used in an all-fiber Yb-doped mode-locked fiber laser at 980 nm. Our work further points the excellent saturable absorption ability of ML-MoS2 in ultrafast photonic applications.

Comparison between iteration schemes for three-dimensional coordinate-transformed saturated-unsaturated flow model

NASA Astrophysics Data System (ADS)

An, Hyunuk; Ichikawa, Yutaka; Tachikawa, Yasuto; Shiiba, Michiharu

2012-11-01

SummaryThree different iteration methods for a three-dimensional coordinate-transformed saturated-unsaturated flow model are compared in this study. The Picard and Newton iteration methods are the common approaches for solving Richards' equation. The Picard method is simple to implement and cost-efficient (on an individual iteration basis). However it converges slower than the Newton method. On the other hand, although the Newton method converges faster, it is more complex to implement and consumes more CPU resources per iteration than the Picard method. The comparison of the two methods in finite-element model (FEM) for saturated-unsaturated flow has been well evaluated in previous studies. However, two iteration methods might exhibit different behavior in the coordinate-transformed finite-difference model (FDM). In addition, the Newton-Krylov method could be a suitable alternative for the coordinate-transformed FDM because it requires the evaluation of a 19-point stencil matrix. The formation of a 19-point stencil is quite a complex and laborious procedure. Instead, the Newton-Krylov method calculates the matrix-vector product, which can be easily approximated by calculating the differences of the original nonlinear function. In this respect, the Newton-Krylov method might be the most appropriate iteration method for coordinate-transformed FDM. However, this method involves the additional cost of taking an approximation at each Krylov iteration in the Newton-Krylov method. In this paper, we evaluated the efficiency and robustness of three iteration methods—the Picard, Newton, and Newton-Krylov methods—for simulating saturated-unsaturated flow through porous media using a three-dimensional coordinate-transformed FDM.

Analogies between the Torque-Free Motion of a Rigid Body about a Fixed Point and Light Propagation in Anisotropic Media

ERIC Educational Resources Information Center

Bellver-Cebreros, Consuelo; Rodriguez-Danta, Marcelo

2009-01-01

An apparently unnoticed analogy between the torque-free motion of a rotating rigid body about a fixed point and the propagation of light in anisotropic media is stated. First, a new plane construction for visualizing this torque-free motion is proposed. This method uses an intrinsic representation alternative to angular momentum and independent of…

Δ isobars and nuclear saturation

NASA Astrophysics Data System (ADS)

Ekström, A.; Hagen, G.; Morris, T. D.; Papenbrock, T.; Schwartz, P. D.

2018-02-01

We construct a nuclear interaction in chiral effective field theory with explicit inclusion of the Δ -isobar Δ (1232 ) degree of freedom at all orders up to next-to-next-to-leading order (NNLO). We use pion-nucleon (π N ) low-energy constants (LECs) from a Roy-Steiner analysis of π N scattering data, optimize the LECs in the contact potentials up to NNLO to reproduce low-energy nucleon-nucleon scattering phase shifts, and constrain the three-nucleon interaction at NNLO to reproduce the binding energy and point-proton radius of 4He. For heavier nuclei we use the coupled-cluster method to compute binding energies, radii, and neutron skins. We find that radii and binding energies are much improved for interactions with explicit inclusion of Δ (1232 ) , while Δ -less interactions produce nuclei that are not bound with respect to breakup into α particles. The saturation of nuclear matter is significantly improved, and its symmetry energy is consistent with empirical estimates.

Light-stimulated cell expansion in bean (Phaseolus vulgaris L.) leaves. II. Quantity and quality of light required

NASA Technical Reports Server (NTRS)

Van Volkenburgh, E.; Cleland, R. E.; Watanabe, M.

1990-01-01

The quantity and quality of light required for light-stimulated cell expansion in leaves of Phaseolus vulgaris L. have been determined. Seedlings were grown in dim red light (RL; 4 micromoles photons m-2 s-1) until cell division in the primary leaves was completed, then excised discs were incubated in 10 mM sucrose plus 10 mM KCl in a variety of light treatments. The growth response of discs exposed to continuous white light (WL) for 16 h was saturated at 100 micromoles m-2 s-1, and did not show reciprocity. Extensive, but not continuous, illumination was needed for maximal growth. The wavelength dependence of disc expansion was determined from fluence-response curves obtained from 380 to 730 nm provided by the Okazaki Large Spectrograph. Blue (BL; 460 nm) and red light (RL; 660 nm) were most effective in promoting leaf cell growth, both in photosynthetically active and inhibited leaf discs. Far-red light (FR; 730 nm) reduced the effectiveness of RL, but not BL, indicating that phytochrome and a separate blue-light receptor mediate expansion of leaf cells.

Three dimensional indoor positioning based on visible light with Gaussian mixture sigma-point particle filter technique

NASA Astrophysics Data System (ADS)

Gu, Wenjun; Zhang, Weizhi; Wang, Jin; Amini Kashani, M. R.; Kavehrad, Mohsen

2015-01-01

Over the past decade, location based services (LBS) have found their wide applications in indoor environments, such as large shopping malls, hospitals, warehouses, airports, etc. Current technologies provide wide choices of available solutions, which include Radio-frequency identification (RFID), Ultra wideband (UWB), wireless local area network (WLAN) and Bluetooth. With the rapid development of light-emitting-diodes (LED) technology, visible light communications (VLC) also bring a practical approach to LBS. As visible light has a better immunity against multipath effect than radio waves, higher positioning accuracy is achieved. LEDs are utilized both for illumination and positioning purpose to realize relatively lower infrastructure cost. In this paper, an indoor positioning system using VLC is proposed, with LEDs as transmitters and photo diodes as receivers. The algorithm for estimation is based on received-signalstrength (RSS) information collected from photo diodes and trilateration technique. By appropriately making use of the characteristics of receiver movements and the property of trilateration, estimation on three-dimensional (3-D) coordinates is attained. Filtering technique is applied to enable tracking capability of the algorithm, and a higher accuracy is reached compare to raw estimates. Gaussian mixture Sigma-point particle filter (GM-SPPF) is proposed for this 3-D system, which introduces the notion of Gaussian Mixture Model (GMM). The number of particles in the filter is reduced by approximating the probability distribution with Gaussian components.

Saturation thresholds of evoked neural and hemodynamic responses in awake and asleep rats

NASA Astrophysics Data System (ADS)

Schei, Jennifer L.; Van Nortwick, Amy S.; Meighan, Peter C.; Rector, David M.

2011-03-01

Neural activation generates a hemodynamic response to the localized region replenishing nutrients to the area. Changes in vigilance state have been shown to alter the vascular response where the vascular response is muted during wake compared to quiet sleep. We tested the saturation thresholds of the neurovascular response in the auditory cortex during wake and sleep by chronically implanting rats with an EEG electrode, a light emitting diode (LED, 600 nm), and photodiode to simultaneously measure evoked response potentials (ERPs) and evoked hemodynamic responses. We stimulated the cortex with a single speaker click delivered at random intervals 2-13 s at varied stimulus intensities ranging from 45-80 dB. To further test the potential for activity related saturation, we sleep deprived animals for 2, 4, or 6 hours and recorded evoked responses during the first hour recovery period. With increasing stimulus intensity, integrated ERPs and evoked hemodynamic responses increased; however the hemodynamic response approached saturation limits at a lower stimulus intensity than the ERP. With longer periods of sleep deprivation, the integrated ERPs did not change but evoked hemodynamic responses decreased. There may be physical limits in cortical blood delivery and vascular compliance, and with extended periods of neural activity during wake, vessels may approach these limits.

Designing display primaries with currently available light sources for UHDTV wide-gamut system colorimetry.

PubMed

Masaoka, Kenichiro; Nishida, Yukihiro; Sugawara, Masayuki

2014-08-11

The wide-gamut system colorimetry has been standardized for ultra-high definition television (UHDTV). The chromaticities of the primaries are designed to lie on the spectral locus to cover major standard system colorimetries and real object colors. Although monochromatic light sources are required for a display to perfectly fulfill the system colorimetry, highly saturated emission colors using recent quantum dot technology may effectively achieve the wide gamut. This paper presents simulation results on the chromaticities of highly saturated non-monochromatic light sources and gamut coverage of real object colors to be considered in designing wide-gamut displays with color filters for the UHDTV.

Changes in retinal venular oxygen saturation predict activity of proliferative diabetic retinopathy 3 months after panretinal photocoagulation.

PubMed

Torp, Thomas Lee; Kawasaki, Ryo; Wong, Tien Yin; Peto, Tunde; Grauslund, Jakob

2018-03-01

Proliferative diabetic retinopathy (PDR) is a severe blinding condition. We investigated whether retinal metabolism, measured by retinal oximetry, may predict PDR activity after panretinal laser photocoagulation (PRP). We performed a prospective, interventional, clinical study of patients with treatment-naive PDR. Wide-field fluorescein angiography (OPTOS, Optomap) and global and focal retinal oximetry (Oxymap T1) were performed at baseline (BL), and 3 months (3M) after PRP. Angiographic findings were used to divide patients according to progression or non-progression of PDR after PRP. We evaluated differences in global and focal retinal oxygen saturation between patients with and without progression of PDR after PRP treatment. We included 45 eyes of 37 patients (median age and duration of diabetes were 51.6 and 20 years). Eyes with progression of PDR developed a higher retinal venous oxygen saturation than eyes with non-progression at 3M (global: +5.9% (95% CI -1.5 to 12.9), focal: +5.4%, (95% CI -4.1 to 14.8)). Likewise, progression of PDR was associated with a lower arteriovenular (AV) oxygen difference between BL and 3M (global: -6.1%, (95% CI -13.4 to -1.4), focal: -4.5% (95% CI -12.1 to 3.2)). In a multiple logistic regression model, increment in global retinal venular oxygen saturation (OR 1.30 per 1%-point increment, p=0.017) and decrement in AV oxygen saturation difference (OR 0.72 per 1%-point increment, p=0.016) at 3M independently predicted progression of PDR. Development of higher retinal venular and lower AV global oxygen saturation independently predicts progression of PDR despite standard PRP and might be a potential non-invasive marker of angiogenic disease activity. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Research on an uplink carrier sense multiple access algorithm of large indoor visible light communication networks based on an optical hard core point process.

PubMed

Nan, Zhufen; Chi, Xuefen

2016-12-20

The IEEE 802.15.7 protocol suggests that it could coordinate the channel access process based on the competitive method of carrier sensing. However, the directionality of light and randomness of diffuse reflection would give rise to a serious imperfect carrier sense (ICS) problem [e.g., hidden node (HN) problem and exposed node (EN) problem], which brings great challenges in realizing the optical carrier sense multiple access (CSMA) mechanism. In this paper, the carrier sense process implemented by diffuse reflection light is modeled as the choice of independent sets. We establish an ICS model with the presence of ENs and HNs for the multi-point to multi-point visible light communication (VLC) uplink communications system. Considering the severe optical ICS problem, an optical hard core point process (OHCPP) is developed, which characterizes the optical CSMA for the indoor VLC uplink communications system. Due to the limited coverage of the transmitted optical signal, in our OHCPP, the ENs within the transmitters' carrier sense region could be retained provided that they could not corrupt the ongoing communications. Moreover, because of the directionality of both light emitting diode (LED) transmitters and receivers, theoretical analysis of the HN problem becomes difficult. In this paper, we derive the closed-form expression for approximating the outage probability and transmission capacity of VLC networks with the presence of HNs and ENs. Simulation results validate the analysis and also show the existence of an optimal physical carrier-sensing threshold that maximizes the transmission capacity for a given emission angle of LED.

Swash saturation: an assessment of available models

NASA Astrophysics Data System (ADS)

Hughes, Michael G.; Baldock, Tom E.; Aagaard, Troels

2018-06-01

An extensive previously published (Hughes et al. Mar Geol 355, 88-97, 2014) field data set representing the full range of micro-tidal beach states (reflective, intermediate and dissipative) is used to investigate swash saturation. Two models that predict the behavior of saturated swash are tested: one driven by standing waves and the other driven by bores. Despite being based on entirely different premises, they predict similar trends in the limiting (saturated) swash height with respect to dependency on frequency and beach gradient. For a given frequency and beach gradient, however, the bore-driven model predicts a larger saturated swash height by a factor 2.5. Both models broadly predict the general behavior of swash saturation evident in the data, but neither model is accurate in detail. While swash saturation in the short-wave frequency band is common on some beach types, it does not always occur across all beach types. Further work is required on wave reflection/breaking and the role of wave-wave and wave-swash interactions to determine limiting swash heights on natural beaches.

Analytical model of a corona discharge from a conical electrode under saturation

NASA Astrophysics Data System (ADS)

Boltachev, G. Sh.; Zubarev, N. M.

2012-11-01

Exact partial solutions are found for the electric field distribution in the outer region of a stationary unipolar corona discharge from an ideal conical needle in the space-charge-limited current mode with allowance for the electric field dependence of the ion mobility. It is assumed that only the very tip of the cone is responsible for the discharge, i.e., that the ionization zone is a point. The solutions are obtained by joining the spherically symmetric potential distribution in the drift space and the self-similar potential distribution in the space-charge-free region. Such solutions are outside the framework of the conventional Deutsch approximation, according to which the space charge insignificantly influences the shape of equipotential surfaces and electric lines of force. The dependence is derived of the corona discharge saturation current on the apex angle of the conical electrode and applied potential difference. A simple analytical model is suggested that describes drift in the point-plane electrode geometry under saturation as a superposition of two exact solutions for the field potential. In terms of this model, the angular distribution of the current density over the massive plane electrode is derived, which agrees well with Warburg's empirical law.

Rapid Transition of the Hole Rashba Effect from Strong Field Dependence to Saturation in Semiconductor Nanowires

NASA Astrophysics Data System (ADS)

Luo, Jun-Wei; Li, Shu-Shen; Zunger, Alex

2017-09-01

The electric field manipulation of the Rashba spin-orbit coupling effects provides a route to electrically control spins, constituting the foundation of the field of semiconductor spintronics. In general, the strength of the Rashba effects depends linearly on the applied electric field and is significant only for heavy-atom materials with large intrinsic spin-orbit interaction under high electric fields. Here, we illustrate in 1D semiconductor nanowires an anomalous field dependence of the hole (but not electron) Rashba effect (HRE). (i) At low fields, the strength of the HRE exhibits a steep increase with the field so that even low fields can be used for device switching. (ii) At higher fields, the HRE undergoes a rapid transition to saturation with a giant strength even for light-atom materials such as Si (exceeding 100 meV Å). (iii) The nanowire-size dependence of the saturation HRE is rather weak for light-atom Si, so size fluctuations would have a limited effect; this is a key requirement for scalability of Rashba-field-based spintronic devices. These three features offer Si nanowires as a promising platform for the realization of scalable complementary metal-oxide-semiconductor compatible spintronic devices.

Dependence of diameters and oxygen saturation of retinal vessels on visual field damage and age in primary open-angle glaucoma.

PubMed

Ramm, Lisa; Jentsch, Susanne; Peters, Sven; Sauer, Lydia; Augsten, Regine; Hammer, Martin

2016-05-01

To investigate the interrelationship between the oxygen supply of the retina and its regulation with the severity of primary open-angle glaucoma (POAG). Central retinal artery (CRAE) and vein (CRVE) diameters and oxygen saturation of peripapillary retinal vessels in 41 patients suffering from POAG (64.1 ± 12.9 years) and 40 healthy volunteers (63.6 ± 14.1 years) were measured using the retinal vessel analyzer. All measures were taken before and during flicker light stimulation. The mean retinal nerve fiber layer thickness (RNFLT) was determined by OCT and the visual field mean defect (MD) was identified using perimetry. In glaucoma patients, CRAE (r = -0.48 p = 0.002) and CRVE (r = -0.394 p = 0.014) at baseline were inversely related to MD, while arterial and venous oxygen saturation showed no significant dependence on the severity of the damage. However, the flicker light-induced change in arterio-venous difference in oxygen saturation was correlated with the MD (r = 0.358 p = 0.027). The diameters of arteries and veins at baseline decreased with reduction of the mean RNFLT (arteries: r = 0.718 p < 0.001; veins: r = 0.685 p < 0.001). Vessel diameters showed a strong correlation with RNFLT and MD. This, as well as the reduction of stimulation-induced change in arterio-venous oxygen saturation difference with visual field loss, may be explained by a reduction of the retinal metabolic demand with progressive loss of neuronal tissue in glaucoma. © 2015 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Nonlinear saturation of the Weibel instability

DOE PAGES

Cagas, P.; Hakim, A.; Scales, W.; ...

2017-11-21

The growth and saturation of magnetic fields due to the Weibel instability (WI) have important implications for laboratory and astrophysical plasmas, and this has drawn significant interest recently. Since the WI can generate a large magnetic field from no initial field, the maximum magnitudes achieved can have significant consequences for a number of applications. Hence, an understanding of the detailed dynamics driving the nonlinear saturation of the WI is important. This work considers the nonlinear saturation of the WI when counter-streaming populations of initially unmagnetized electrons are perturbed by a magnetic field oriented perpendicular to the direction of streaming. Previousmore » works have found magnetic trapping to be important and connected electron skin depth spatial scales to the nonlinear saturation of the WI. The results presented in this work are consistent with these findings for a high-temperature case. However, using a high-order continuum kinetic simulation tool, this work demonstrates that when the electron populations are colder, a significant electrostatic potential develops that works with the magnetic field to create potential wells. The electrostatic field develops due to transverse flows induced by the WI and in some cases is strengthened by a secondary instability. This field plays a key role in saturation of the WI for colder populations. In conclusion, the role of the electrostatic potential in Weibel instability saturation has not been studied in detail previously.« less

Nonlinear saturation of the Weibel instability

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

Cagas, P.; Hakim, A.; Scales, W.

The growth and saturation of magnetic fields due to the Weibel instability (WI) have important implications for laboratory and astrophysical plasmas, and this has drawn significant interest recently. Since the WI can generate a large magnetic field from no initial field, the maximum magnitudes achieved can have significant consequences for a number of applications. Hence, an understanding of the detailed dynamics driving the nonlinear saturation of the WI is important. This work considers the nonlinear saturation of the WI when counter-streaming populations of initially unmagnetized electrons are perturbed by a magnetic field oriented perpendicular to the direction of streaming. Previousmore » works have found magnetic trapping to be important and connected electron skin depth spatial scales to the nonlinear saturation of the WI. The results presented in this work are consistent with these findings for a high-temperature case. However, using a high-order continuum kinetic simulation tool, this work demonstrates that when the electron populations are colder, a significant electrostatic potential develops that works with the magnetic field to create potential wells. The electrostatic field develops due to transverse flows induced by the WI and in some cases is strengthened by a secondary instability. This field plays a key role in saturation of the WI for colder populations. In conclusion, the role of the electrostatic potential in Weibel instability saturation has not been studied in detail previously.« less

Photovoltaic powered ultraviolet and visible light-emitting diodes for sustainable point-of-use disinfection of drinking waters.

PubMed

Lui, Gough Yumu; Roser, David; Corkish, Richard; Ashbolt, Nicholas; Jagals, Paul; Stuetz, Richard

2014-09-15

For many decades, populations in rural and remote developing regions will be unable to access centralised piped potable water supplies, and indeed, decentralised options may be more sustainable. Accordingly, improved household point-of-use (POU) disinfection technologies are urgently needed. Compared to alternatives, ultraviolet (UV) light disinfection is very attractive because of its efficacy against all pathogen groups and minimal operational consumables. Though mercury arc lamp technology is very efficient, it requires frequent lamp replacement, involves a toxic heavy metal, and their quartz envelopes and sleeves are expensive, fragile and require regular cleaning. An emerging alternative is semiconductor-based units where UV light emitting diodes (UV-LEDs) are powered by photovoltaics (PV). Our review charts the development of these two technologies, their current status, and challenges to their integration and POU application. It explores the themes of UV-C-LEDs, non-UV-C LED technology (e.g. UV-A, visible light, Advanced Oxidation), PV power supplies, PV/LED integration and POU suitability. While UV-C LED technology should mature in the next 10 years, research is also needed to address other unresolved barriers to in situ application as well as emerging research opportunities especially UV-A, photocatalyst/photosensitiser use and pulsed emission options. Copyright © 2014 Elsevier B.V. All rights reserved.

Wavelength-versatile graphene-gold film saturable absorber mirror for ultra-broadband mode-locking of bulk lasers.

PubMed

Ma, Jie; Xie, Guoqiang; Lv, Peng; Gao, Wenlan; Yuan, Peng; Qian, Liejia; Griebner, Uwe; Petrov, Valentin; Yu, Haohai; Zhang, Huaijin; Wang, Jiyang

2014-05-23

An ultra-broadband graphene-gold film saturable absorber mirror (GG-SAM) with a spectral coverage exceeding 1300 nm is experimentally demonstrated for mode-locking of bulk solid-state lasers. Owing to the p-type doping effect caused by graphene-gold film interaction, the graphene on gold-film substrate shows a remarkably lower light absorption relative to pristine graphene, which is very helpful to achieve continuous-wave mode-locking in low-gain bulk lasers. Using the GG-SAM sample, stable mode-locking is realized in a Yb:YCOB bulk laser near 1 μm, a Tm:CLNGG bulk laser near 2 μm and a Cr:ZnSe bulk laser near 2.4 μm. The saturable absorption is characterised at an intermediate wavelength of 1.56 μm by pump-probe measurements. The as-fabricated GG-SAM with ultra-broad bandwidth, ultrafast recovery time, low absorption, and low cost has great potential as a universal saturable absorber mirror for mode-locking of various bulk lasers with unprecedented spectral coverage.

Wavelength-Versatile Graphene-Gold Film Saturable Absorber Mirror for Ultra-Broadband Mode-Locking of Bulk Lasers

PubMed Central

Ma, Jie; Xie, Guoqiang; Lv, Peng; Gao, Wenlan; Yuan, Peng; Qian, Liejia; Griebner, Uwe; Petrov, Valentin; Yu, Haohai; Zhang, Huaijin; Wang, Jiyang

2014-01-01

An ultra-broadband graphene-gold film saturable absorber mirror (GG-SAM) with a spectral coverage exceeding 1300 nm is experimentally demonstrated for mode-locking of bulk solid-state lasers. Owing to the p-type doping effect caused by graphene-gold film interaction, the graphene on gold-film substrate shows a remarkably lower light absorption relative to pristine graphene, which is very helpful to achieve continuous-wave mode-locking in low-gain bulk lasers. Using the GG-SAM sample, stable mode-locking is realized in a Yb:YCOB bulk laser near 1 μm, a Tm:CLNGG bulk laser near 2 μm and a Cr:ZnSe bulk laser near 2.4 μm. The saturable absorption is characterised at an intermediate wavelength of 1.56 μm by pump-probe measurements. The as-fabricated GG-SAM with ultra-broad bandwidth, ultrafast recovery time, low absorption, and low cost has great potential as a universal saturable absorber mirror for mode-locking of various bulk lasers with unprecedented spectral coverage. PMID:24853072

Investigation of spatial resolution dependent variability in transcutaneous oxygen saturation using point spectroscopy system

NASA Astrophysics Data System (ADS)

Philimon, Sheena P.; Huong, Audrey K. C.; Ngu, Xavier T. I.

2017-08-01

This paper aims to investigate the variation in one’s percent mean transcutaneous oxygen saturation (StO2) with differences in spatial resolution of data. This work required the knowledge of extinction coefficient of hemoglobin derivatives in the wavelength range of 520 - 600 nm to solve for the StO2 value via an iterative fitting procedure. A pilot study was conducted on three healthy subjects with spectroscopic data collected from their right index finger at different arbitrarily selected distances. The StO2 value estimated by Extended Modified Lambert Beer (EMLB) model revealed a higher mean StO2 of 91.1 ± 1.3% at a proximity distance of 30 mm compared to 60.83 ± 2.8% at 200 mm. The results showed a high correlation between data spatial resolution and StO2 value, and revealed a decrease in StO2 value as the sampling distance increased. The preliminary findings from this study contribute to the knowledge of the appropriate distance range for consistent and high repeatability measurement of skin oxygenation.

Saturated liquid density of 1,1-difluoroethane(R 152a) and thermodynamic properties along the vapor-liquid coexistence curve

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

Sato, H.; Okada, M.; Uematsu, M.

1987-01-01

Saturated liquid densities of 1,1-difluoroethane (CH/sub 3/CHF/sub 2/) are measured at temperatures from 223 K to 363 K with the estimated uncertainty of +-0.2% by a magnetic densimetry. The experimental results are compared with the available experimental data and some correlations and equations of state. A simple correlation for the saturated liquid density is developed as a function of temperature. This correlation covers the temperature range up to the critical point which reproduces the present experimental results with the percent means deviation of 0.11%. Adding the available experimental data with respect to the vapor pressure, critical parameters, saturated vapor density,more » and the second virial coefficient to the present saturated liquid density data, the parameters of the Redlich-Kwong-Soave equation of state are determined and the thermodynamic properties along the vapor-liquid coexistence curve are derived.« less

Blowing bubbles in Lennard-Jonesium along the saturation curve.

PubMed

Ashbaugh, Henry S

2009-05-28

Extensive molecular simulations of the Lennard-Jones fluid have been performed to determine its liquid-vapor coexistence properties and solvent contact densities with cavities up to ten times the diameter of the solvent from the triple point to the critical point. These simulations are analyzed using a revised scaled-particle theory [H. S. Ashbaugh and L. R. Pratt, Rev. Mod. Phys. 78, 159 (2006)] to evaluate the thermodynamics of cavity solvation and curvature dependent interfacial properties along the saturation curve. While the thermodynamic signatures of cavity solvation are distinct from those in water, exhibiting a chemical potential dominated by a large temperature independent enthalpy, the solvent dewets cavities of increasing size similar with water near coexistence. The interfacial tension for forming a liquid-wall interface is found to be consistently greater than the liquid-vapor surface tension of the Lennard-Jones fluid by up to 10% and potentially reflects the suppression of high amplitude fluctuations at the cavity surface. The first-order curvature correction for the surface tension is negative and appears to diverge to negative infinity at temperatures approaching the critical point. Our results point to the success of the revised scaled-particle theory at bridging molecular and macroscopic descriptions of cavity solvation.

Visual tuning and metrical perception of realistic point-light dance movements.

PubMed

Su, Yi-Huang

2016-03-07

Humans move to music spontaneously, and this sensorimotor coupling underlies musical rhythm perception. The present research proposed that, based on common action representation, different metrical levels as in auditory rhythms could emerge visually when observing structured dance movements. Participants watched a point-light figure performing basic steps of Swing dance cyclically in different tempi, whereby the trunk bounced vertically at every beat and the limbs moved laterally at every second beat, yielding two possible metrical periodicities. In Experiment 1, participants freely identified a tempo of the movement and tapped along. While some observers only tuned to the bounce and some only to the limbs, the majority tuned to one level or the other depending on the movement tempo, which was also associated with individuals' preferred tempo. In Experiment 2, participants reproduced the tempo of leg movements by four regular taps, and showed a slower perceived leg tempo with than without the trunk bouncing simultaneously in the stimuli. This mirrors previous findings of an auditory 'subdivision effect', suggesting the leg movements were perceived as beat while the bounce as subdivisions. Together these results support visual metrical perception of dance movements, which may employ similar action-based mechanisms to those underpinning auditory rhythm perception.

Visual tuning and metrical perception of realistic point-light dance movements

PubMed Central

Su, Yi-Huang

2016-01-01

Humans move to music spontaneously, and this sensorimotor coupling underlies musical rhythm perception. The present research proposed that, based on common action representation, different metrical levels as in auditory rhythms could emerge visually when observing structured dance movements. Participants watched a point-light figure performing basic steps of Swing dance cyclically in different tempi, whereby the trunk bounced vertically at every beat and the limbs moved laterally at every second beat, yielding two possible metrical periodicities. In Experiment 1, participants freely identified a tempo of the movement and tapped along. While some observers only tuned to the bounce and some only to the limbs, the majority tuned to one level or the other depending on the movement tempo, which was also associated with individuals’ preferred tempo. In Experiment 2, participants reproduced the tempo of leg movements by four regular taps, and showed a slower perceived leg tempo with than without the trunk bouncing simultaneously in the stimuli. This mirrors previous findings of an auditory ‘subdivision effect’, suggesting the leg movements were perceived as beat while the bounce as subdivisions. Together these results support visual metrical perception of dance movements, which may employ similar action-based mechanisms to those underpinning auditory rhythm perception. PMID:26947252

Point-of-use water disinfection using ultraviolet and visible light-emitting diodes.

PubMed

Lui, Gough Yumu; Roser, David; Corkish, Richard; Ashbolt, Nicholas J; Stuetz, Richard

2016-05-15

Improvements in point-of-use (POU) drinking water disinfection technologies for remote and regional communities are urgently needed. Conceptually, UV-C light-emitting diodes (LEDs) overcome many drawbacks of low-pressure mercury tube based UV devices, and UV-A or visible light LEDs also show potential. To realistically evaluate the promise of LED disinfection, our study assessed the performance of a model 1.3 L reactor, similar in size to solar disinfection bottles. In all, 12 different commercial or semi-commercial LED arrays (270-740 nm) were compared for their ability to inactivate Escherichia coli K12 ATCC W3110 and Enterococcus faecalis ATCC 19433 over 6h. Five log10 and greater reductions were consistently achieved using the 270, 365, 385 and 405 nm arrays. The output of the 310 nm array was insufficient for useful disinfection while 430 and 455 nm performance was marginal (≈ 4.2 and 2.3-log10s E. coli and E. faecalis over the 6h). No significant disinfection was observed with the 525, 590, 623, 660 and 740 nm arrays. Delays in log-phase inactivation of E. coli were observed, particularly with UV-A wavelengths. The radiation doses required for >3-log10 reduction of E. coli and E. faecalis differed by 10 fold at 270 nm but only 1.5-2.5 fold at 365-455 nm. Action spectra, consistent with the literature, were observed with both indicators. The design process revealed cost and technical constraints pertaining to LED electrical efficiency, availability and lifetime. We concluded that POU LED disinfection using existing LED technology is already technically possible. UV-C LEDs offer speed and energy demand advantages, while UV-A/violet units are safer. Both approaches still require further costing and engineering development. Our study provides data needed for such work. Copyright © 2016 Elsevier B.V. All rights reserved.

A missense mutation in the agouti signaling protein gene (ASIP) is associated with the no light points coat phenotype in donkeys.

PubMed

Abitbol, Marie; Legrand, Romain; Tiret, Laurent

2015-04-08

Seven donkey breeds are recognized by the French studbook and are characterized by a black, bay or grey coat colour including light cream-to-white points (LP). Occasionally, Normand bay donkeys give birth to dark foals that lack LP and display the no light points (NLP) pattern. This pattern is more frequent and officially recognized in American miniature donkeys. The LP (or pangare) phenotype resembles that of the light bellied agouti pattern in mouse, while the NLP pattern resembles that of the mammalian recessive black phenotype; both phenotypes are associated with the agouti signaling protein gene (ASIP). We used a panel of 127 donkeys to identify a recessive missense c.349 T > C variant in ASIP that was shown to be in complete association with the NLP phenotype. This variant results in a cysteine to arginine substitution at position 117 in the ASIP protein. This cysteine is highly-conserved among vertebrate ASIP proteins and was previously shown by mutagenesis experiments to lie within a functional site. Altogether, our results strongly support that the identified mutation is causative of the NLP phenotype. Thus, we propose to name the c.[349 T > C] allele in donkeys, the a(nlp) allele, which enlarges the panel of coat colour alleles in donkeys and ASIP recessive loss-of-function alleles in animals.

Light response characteristics of a morphologically diverse group of southern hemisphere conifers as measured by chlorophyll fluorescence.

PubMed

Brodribb, T; Hill, Robert S

1997-03-01

Unlike northern hemisphere conifer families, the southern family, Podocarpaceae, produces a great variety of foliage forms ranging from functionally broad-, to needle-leaved. The production of broad photosynthetic surfaces in podocarps has been linked qualitatively to low-light-environments, and we undertook to assess the validity of this assumption by measuring the light response of a morphologically diverse group of podocarps. The light response, as apparent photochemical electron transport rate (ETR), was measured by modulated fluorescence in ten species of this family and six associated species (including five Cupressaceae and one functionally needle-leaved angiosperm) all grown under identical glasshouse conditions. In all species, ETR was found to increase as light intensity increased, reaching a peak value (ETR max ) at saturating quantum flux (PPFD sat ), and decreasing thereafter. ETR max ranged from 217 μmol electrons · m -2  · s -1 at a PPFD sat of 1725 μmol photons · m -2  · s -1 in Actinostrobus acuminatus to an ETR of 60 μmol electrons · m -2  · s -1 at a PPFD sat of 745 μmol electrons · m -2  · s -1 in Podocarpus dispermis. Good correlations were observed between ETR max and both PPFD sat and maximum assimilation rate measured by gas-exchange analysis. The effective quantum yield at light saturation remained constant in all species with an average value of 0.278 ± 0.0035 determined for all 16 species. Differences in the shapes of light response curves were related to differences in the response of non-photochemical quenching (q n ), with q n saturating faster in species with low PPFD sat . Amongst the species of Podocarpaceae, the log of average shoot width was well correlated with PPFD sat , wider leaves saturating at lower light intensities. This suggests that broadly flattened shoots in the Podocarpaceae are an adaptation to low light intensity.

Distributed Saturation

NASA Technical Reports Server (NTRS)

Chung, Ming-Ying; Ciardo, Gianfranco; Siminiceanu, Radu I.

2007-01-01

The Saturation algorithm for symbolic state-space generation, has been a recent break-through in the exhaustive veri cation of complex systems, in particular globally-asyn- chronous/locally-synchronous systems. The algorithm uses a very compact Multiway Decision Diagram (MDD) encoding for states and the fastest symbolic exploration algo- rithm to date. The distributed version of Saturation uses the overall memory available on a network of workstations (NOW) to efficiently spread the memory load during the highly irregular exploration. A crucial factor in limiting the memory consumption during the symbolic state-space generation is the ability to perform garbage collection to free up the memory occupied by dead nodes. However, garbage collection over a NOW requires a nontrivial communication overhead. In addition, operation cache policies become critical while analyzing large-scale systems using the symbolic approach. In this technical report, we develop a garbage collection scheme and several operation cache policies to help on solving extremely complex systems. Experiments show that our schemes improve the performance of the original distributed implementation, SmArTNow, in terms of time and memory efficiency.

Energetic aspects of the light activation of two chloroplast enzymes: fructose-1,6-bisphosphatase and NADP-malate dehydrogenase.

PubMed

Miginiac-Maslow, M; Jacquot, J P; Droux, M

1985-09-01

The light energy requirements for photoactivation of two chloroplast enzymes: fructose-1,6-bisphosphatase and NADP-malate dehydrogenase were studied in a reconstituted chloroplast system. This system comprised isolated pea thylakoids, ferredoxin (Fd), ferredoxin-thioredoxin reductase (FTR) thioredoxinm and f (Tdm, Tdf) and the photoactivatable enzyme. Light-saturation curves of the photoactivation process were established with once washed thylakoids which did not require the addition of Td for light activation. They exhibited a plateau at 10 W·m(-2) under nitrogen and 50 W·m(-2) under air, while NADP photoreduction was saturated at 240 W·m(-2). Cyclic and pseudocyclic phosphorylations saturated at identical levels as enzyme photoactivations. All these observations suggested that the shift of the light saturation plateau towards higher values under air was due to competing oxygen-dependent reactions. With twice washed thylakoids, which required Td for enzyme light-activation, photophosphorylation was stimulated under N2 by the addition of the components of the photoactivation system. Its rate increased with increasing Td concentrations, just as did the enzyme photoactivation rate, while varying the target enzyme concentration had only a weak effect. Considering that Td concentrations were in a large excess over target enzyme concentrations, it may be assumed that the observed ATP synthesis was essentially dependent on the rate of Td reduction.Under air, Fd-dependent pseudo-cyclic photophosphorylation was not stimulated by the addition of the other enzyme photoactivation components, suggesting that an important site of action of O2 was located at the level of Fd.

Saturation of the anisoplanatic error in horizontal imaging scenarios

NASA Astrophysics Data System (ADS)

Beck, Jeffrey; Bos, Jeremy P.

2017-09-01

We evaluate the piston-removed anisoplanatic error for smaller apertures imaging over long horizontal paths. Previous works have shown that the piston and tilt compensated anisoplanatic error saturates to values less than one squared radian. Under these conditions the definition of the isoplanatic angle is unclear. These works focused on nadir pointing telescope systems with aperture sizes between five meters and one half meter. We directly extend this work to horizontal imaging scenarios with aperture sizes smaller than one half meter. We assume turbulence is constant along the imaging path and that the ratio of the aperture size to the atmospheric coherence length is on the order of unity.

Light adaptation alters the source of inhibition to the mouse retinal OFF pathway

PubMed Central

Mazade, Reece E.

2013-01-01

Sensory systems must avoid saturation to encode a wide range of stimulus intensities. One way the retina accomplishes this is by using both dim-light-sensing rod and bright-light-sensing cone photoreceptor circuits. OFF cone bipolar cells are a key point in this process, as they receive both excitatory input from cones and inhibitory input from AII amacrine cells via the rod pathway. However, in addition to AII amacrine cell input, other inhibitory inputs from cone pathways also modulate OFF cone bipolar cell light signals. It is unknown how these inhibitory inputs to OFF cone bipolar cells change when switching between rod and cone pathways or whether all OFF cone bipolar cells receive rod pathway input. We found that one group of OFF cone bipolar cells (types 1, 2, and 4) receive rod-mediated inhibitory inputs that likely come from the rod-AII amacrine cell pathway, while another group of OFF cone bipolar cells (type 3) do not. In both cases, dark-adapted rod-dominant light responses showed a significant contribution of glycinergic inhibition, which decreased with light adaptation and was, surprisingly, compensated by an increase in GABAergic inhibition. As GABAergic input has distinct timing and spatial spread from glycinergic input, a shift from glycinergic to GABAergic inhibition could significantly alter OFF cone bipolar cell signaling to downstream OFF ganglion cells. Larger GABAergic input could reflect an adjustment of OFF bipolar cell spatial inhibition, which may be one mechanism that contributes to retinal spatial sensitivity in the light. PMID:23926034

Saturation of radiation-induced parametric instabilities by excitation of Langmuir turbulence

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

Dubois, D.F.; Rose, H.A.; Russell, D.

1995-12-01

Progress made in the last few years in the calculation of the saturation spectra of parametric instabilities which involve Langmuir daughter waves will be reviewed. These instabilities include the ion acoustic decay instability, the two plasmon decay instability (TPDI), and stimulated Raman scattering (SRS). In particular I will emphasize spectral signatures which can be directly compared with experiment. The calculations are based on reduced models of driven Laugmuir turbulence. Thomson scattering from hf-induced Langmuir turbulence in the unpreconditioned ionosphere has resulted in detailed agreement between theory and experiment at early times. Strong turbulence signatures dominate in this regime where themore » weak turbulence approximation fails completely. Recent experimental studies of the TPDI have measured the Fourier spectra of Langmuir waves as well as the angular and frequency, spectra of light emitted near 3/2 of the pump frequency again permitting some detailed comparisons with theory. The experiments on SRS are less detailed but by Thomson scattering the secondary decay of the daughter Langmuir wave has been observed. Scaling laws derived from a local model of SRS saturation are compared with full simulations and recent Nova experiments.« less

CO2CRC's Otway Residual Saturation and Dissolution Test: Using Reactive Ester Tracers to Determine Residual CO2 Saturation

NASA Astrophysics Data System (ADS)

Myers, M.; Stalker, L.; LaForce, T.; Pejcic, B.; Dyt, C.; Ho, K.; Ennis-King, J.

2013-12-01

Residual trapping, that is CO2 held in the rock pore space due to capillarity, is an important storage mechanism in geo-sequestration of over the short to medium term (up to 1000 years). As such residual CO2 saturation is a critical reservoir parameter for assessing the storage capacity and security of carbon capture and storage (CCS). As a component of the CO2CRC's Residual Gas Saturation and Dissolution Test at the CO2CRC Otway Project site in Victoria (Australia), we have recently tested a suite of reactive esters (triacetin, tripropionin and propylene glycol diacetate) in a single well chemical tracer test to determine residual CO2 saturation. The goal of this project was to assess and validate a suite of possible tests that could be implemented to determine residual CO2 saturation. For this test, the chemical tracers were injected with a saturated CO2/water mixture into the formation (that is already at residual CO2 saturation) where they were allowed to 'soak' for approximately 10 days allowing for the partial hydrolysis of the esters to their corresponding carboxylic acids and alcohols. Water containing the tracers was then produced from the well resulting in over 600 tracer samples over a period of 12 hours. A selection of these samples were analysed for tracer content and to establish tracer breakthrough curves. To understand the behaviour of these chemical tracers in the downhole environment containing residually trapped supercritical CO2 and formation water, it is necessary to determine the supercritical CO2/water partition coefficients. We have previously determined these in the laboratory (Myers et al., 2012) and they are used here to model the tracer behaviour and provide an estimate of the residual CO2 saturation. Two different computational simulators were used to analyse the tracer breakthrough profiles. The first is based on simple chromatographic retardation and has been used extensively in single well chemical tracer tests to determine residual

Three-dimensional displacement measurement of image point by point-diffraction interferometry

NASA Astrophysics Data System (ADS)

He, Xiao; Chen, Lingfeng; Meng, Xiaojie; Yu, Lei

2018-01-01

This paper presents a method for measuring the three-dimensional (3-D) displacement of an image point based on point-diffraction interferometry. An object Point-light-source (PLS) interferes with a fixed PLS and its interferograms are captured by an exit pupil. When the image point of the object PLS is slightly shifted to a new position, the wavefront of the image PLS changes. And its interferograms also change. Processing these figures (captured before and after the movement), the wavefront difference of the image PLS can be obtained and it contains the information of three-dimensional (3-D) displacement of the image PLS. However, the information of its three-dimensional (3-D) displacement cannot be calculated until the distance between the image PLS and the exit pupil is calibrated. Therefore, we use a plane-parallel-plate with a known refractive index and thickness to determine this distance, which is based on the Snell's law for small angle of incidence. Thus, since the distance between the exit pupil and the image PLS is a known quantity, the 3-D displacement of the image PLS can be simultaneously calculated through two interference measurements. Preliminary experimental results indicate that its relative error is below 0.3%. With the ability to accurately locate an image point (whatever it is real or virtual), a fiber point-light-source can act as the reticle by itself in optical measurement.

Determination of near-saturated hydraulic conductivity by automated minidisk infiltrometer

NASA Astrophysics Data System (ADS)

Klipa, Vladimir; Snehota, Michal; Dohnal, Michal; Zumr, David

2013-04-01

Numerical models in surface and subsurface hydrology require knowledge of infiltration properties of soils for their routine use in the field of water management, environmental protection or agriculture. A new automated tension infiltration module has been designed at the Faculty of Civil Engineering, Czech Technical University in Prague to facilitate the measurements of near-saturated hydraulic conductivity. In the proposed infiltration module the amount of infiltrated water is registered via changes of buoyant force of stationary float attached to the load cell. Presented setup consists of six mini-disk infiltrometer modules held in the light aluminum frame and two Mariotte's bottles. Three infiltrometer modules connected to each Mariotte's bottle allow performing six simultaneous measurements at two different pressure heads. Infiltration modules are connected to the automatic data logging system and consist of: plastic cover with the integrated load cell and the float, reservoir tube (external diameter of 50 mm), and sintered stainless steel plate (diameter of 44.5 mm). The newly developed device was used for determination of near-saturated hydraulic conductivity of soils in experimental catchments Uhlirska (Jizera Mountains, Northern Bohemia) and Kopaninsky creek (Bohemian-Moravian Highlands). The acquired data show a good agreement with the data obtained from previous measurements.

Electrical conductivity modeling in fractal non-saturated porous media

NASA Astrophysics Data System (ADS)

Wei, W.; Cai, J.; Hu, X.; Han, Q.

2016-12-01

The variety of electrical conductivity in non-saturated conditions is important to study electric conduction in natural sedimentary rocks. The electrical conductivity in completely saturated porous media is a porosity-function representing the complex connected behavior of single conducting phases (pore fluid). For partially saturated conditions, the electrical conductivity becomes even more complicated since the connectedness of pore. Archie's second law is an empirical electrical conductivity-porosity and -saturation model that has been used to predict the formation factor of non-saturated porous rock. However, the physical interpretation of its parameters, e.g., the cementation exponent m and the saturation exponent n, remains questionable. On basis of our previous work, we combine the pore-solid fractal (PSF) model to build an electrical conductivity model in non-saturated porous media. Our theoretical porosity- and saturation-dependent models contain endmember properties, such as fluid electrical conductivities, pore fractal dimension and tortuosity fractal dimension (representing the complex degree of electrical flowing path). We find the presented model with non-saturation-dependent electrical conductivity datasets indicate excellent match between theory and experiments. This means the value of pore fractal dimension and tortuosity fractal dimension change from medium to medium and depends not only on geometrical properties of pore structure but also characteristics of electrical current flowing in the non-saturated porous media.

Perfect Lighting for Facial Photography in Aesthetic Surgery: Ring Light.

PubMed

Dölen, Utku Can; Çınar, Selçuk

2016-04-01

Photography is indispensable for plastic surgery. On-camera flashes can result in bleached out detail and colour. This is why most of the plastic surgery clinics prefer studio lighting similar to professional photographers'. In this article, we want to share a simple alternative to studio lighting that does not need extra space: Ring light. We took five different photographs of the same person with five different camera and lighting settings: Smartphone and ring light; point and shoot camera and on-camera flash; point and shoot camera and studio lighting; digital single-lens reflex (DLSR) camera and studio lighting; DSLR and ring light. Then, those photographs were assessed objectively with an online survey of five questions answered by three distinct populations: plastic surgeons (n: 28), professional portrait photographers (n: 24) and patients (n: 22) who had facial aesthetic procedures. Compared to the on-camera flash, studio lighting better showed the wrinkles of the subject. The ring light facilitated the perception of the wrinkles by providing homogenous soft light in a circular shape rather than bursting flashes. The combination of a DSLR camera and ring light gave the oldest looking subject according to 64 % of responders. The DSLR camera and the studio lighting demonstrated the youngest looking subject according to 70 % of the responders. The majority of the responders (78 %) chose the combination of DSLR camera and ring light that exhibited the wrinkles the most. We suggest using a ring light to obtain well-lit photographs without loss of detail, with any type of cameras. However, smartphones must be avoided if standard pictures are desired. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Progress in characterizing the multidimensional color quality properties of white LED light sources

NASA Astrophysics Data System (ADS)

Teunissen, Kees; Hoelen, Christoph

2016-03-01

With the introduction of solid state light sources, the variety in emission spectra is almost unlimited. However, the set of standardized parameters to characterize a white LED light source, such as correlated color temperature (CCT) and CIE general color rendering index (Ra), is known to be limited and insufficient for describing perceived differences between light sources. Several characterization methods have been proposed over the past decades, but their contribution to perceived color quality has not always been validated. To gain more insight in the relevant characteristics of the emission spectra for specific applications, we have conducted a perception experiment to rate the attractiveness of three sets of objects, including fresh food, packaging materials and skin tones. The objects were illuminated with seven different combinations of Red, Green, Blue, Amber and White LEDs, all with the same CCT and illumination level, but with differences in Ra and color saturation. The results show that, in general, object attractiveness does not correlate well with Ra, but shows a positive correlation with saturation increase for two out of three applications. There is no clear relation between saturation and skin tone attractiveness, partly due to differences in preference between males and females. A relative gamut area index (Ga) represents the average change in saturation and a complementary color vector graphic shows the direction and magnitude of chromatic differences for the eight CIE-1974 test-color samples. Together with the CIE general color rendering index (Ra) they provide useful information for designing and optimizing application specific emission spectra.

Complex Light

NASA Astrophysics Data System (ADS)

Secor, Jeff; Alfano, Robert; Ashrafi, Solyman

2017-01-01

The emerging field of complex light-the study and application of custom light beams with tailored intensity, polarization or phase-is a focal point for fundamental breakthroughs in optical science. As this review will show, those advances in fundamental understanding, coupled with the latest developments in complex light generation, are translating into a range of diverse and cross-disciplinary applications that span microscopy, high-data-rate communications, optical trapping and quantum optics. We can expect more twists along the way, too, as researchers seek to manipulate and control the propagation speed of complex light beams, while others push the more exotic possibilities afforded by complex light in quantum-entanglement experiments.

A 3D image sensor with adaptable charge subtraction scheme for background light suppression

NASA Astrophysics Data System (ADS)

Shin, Jungsoon; Kang, Byongmin; Lee, Keechang; Kim, James D. K.

2013-02-01

We present a 3D ToF (Time-of-Flight) image sensor with adaptive charge subtraction scheme for background light suppression. The proposed sensor can alternately capture high resolution color image and high quality depth map in each frame. In depth-mode, the sensor requires enough integration time for accurate depth acquisition, but saturation will occur in high background light illumination. We propose to divide the integration time into N sub-integration times adaptively. In each sub-integration time, our sensor captures an image without saturation and subtracts the charge to prevent the pixel from the saturation. In addition, the subtraction results are cumulated N times obtaining a final result image without background illumination at full integration time. Experimental results with our own ToF sensor show high background suppression performance. We also propose in-pixel storage and column-level subtraction circuit for chiplevel implementation of the proposed method. We believe the proposed scheme will enable 3D sensors to be used in out-door environment.

La Saturated Absorption Spectroscopy for Applications in Quantum Information

NASA Astrophysics Data System (ADS)

Becker, Patrick; Donoghue, Liz; Dungan, Kristina; Liu, Jackie; Olmschenk, Steven

2015-05-01

Quantum information may revolutionize computation and communication by utilizing quantum systems based on matter quantum bits and entangled light. Ions are excellent candidates for quantum bits as they can be well-isolated from unwanted external influences by trapping and laser cooling. Doubly-ionized lanthanum in particular shows promise for use in quantum information as it has infrared transitions in the telecom band, with low attenuation in standard optical fiber, potentially allowing for long distance information transfer. However, the hyperfine splittings of the lowest energy levels, required for laser cooling, have not been measured. We present progress and recent results towards measuring the hyperfine splittings of these levels in lanthanum by saturated absorption spectroscopy with a hollow cathode lamp. This research is supported by the Army Research Office, Research Corporation for Science Advancement, and Denison University.

Rapid Transition of the Hole Rashba Effect from Strong Field Dependence to Saturation in Semiconductor Nanowires.

PubMed

Luo, Jun-Wei; Li, Shu-Shen; Zunger, Alex

2017-09-22

The electric field manipulation of the Rashba spin-orbit coupling effects provides a route to electrically control spins, constituting the foundation of the field of semiconductor spintronics. In general, the strength of the Rashba effects depends linearly on the applied electric field and is significant only for heavy-atom materials with large intrinsic spin-orbit interaction under high electric fields. Here, we illustrate in 1D semiconductor nanowires an anomalous field dependence of the hole (but not electron) Rashba effect (HRE). (i) At low fields, the strength of the HRE exhibits a steep increase with the field so that even low fields can be used for device switching. (ii) At higher fields, the HRE undergoes a rapid transition to saturation with a giant strength even for light-atom materials such as Si (exceeding 100 meV Å). (iii) The nanowire-size dependence of the saturation HRE is rather weak for light-atom Si, so size fluctuations would have a limited effect; this is a key requirement for scalability of Rashba-field-based spintronic devices. These three features offer Si nanowires as a promising platform for the realization of scalable complementary metal-oxide-semiconductor compatible spintronic devices.

Contribution to modeling the viscosity Arrhenius-type equation for saturated pure fluids

NASA Astrophysics Data System (ADS)

Tian, Jianxiang; Zhang, Laibin

2016-09-01

Recently, Haj-Kacem et al. proposed an equation modeling the relationship between the two parameters of viscosity Arrhenius-type equations [Fluid Phase Equilibria 383, 11 (2014)]. The authors found that the two parameters are dependent upon each other in an exponential function form. In this paper, we reconsidered their ideas and calculated the two parameter values for 49 saturated pure fluids by using the experimental data in the NIST WebBook. Our conclusion is different with the ones of Haj-Kacem et al. We found that (the linearity shown by) the Arrhenius equation stands strongly only in low temperature range and that the two parameters of the Arrhenius equation are independent upon each other in the whole temperature range from the triple point to the critical point.

Visual search and coordination changes in response to video and point-light demonstrations without KR.

PubMed

Horn, R R; Williams, A M; Scott, M A; Hodges, N J

2005-07-01

The authors examined the observational learning of 24 participants whom they constrained to use the model by removing intrinsic visual knowledge of results (KR). Matched participants assigned to video (VID), point-light (PL), and no-model (CON) groups performed a soccer-chipping task in which vision was occluded at ball contact. Pre- and posttests were interspersed with alternating periods of demonstration and acquisition. The authors assessed delayed retention 2-3 days later. In support of the visual perception perspective, the participants who observed the models showed immediate and enduring changes to more closely imitate the model's relative motion. While observing the demonstration, the PL group participants were more selective in their visual search than were the VID group participants but did not perform more accurately or learn more.

Impacts of CO2 Enrichment on Productivity and Light Requirements of Eelgrass.

PubMed

Zimmerman, R. C.; Kohrs, D. G.; Steller, D. L.; Alberte, R. S.

1997-10-01

Seagrasses, although well adapted for submerged existence, are CO2-limited and photosynthetically inefficient in seawater. This leads to high light requirements for growth and survival and makes seagrasses vulnerable to light limitation. We explored the long-term impact of increased CO2 availability on light requirements, productivity, and C allocation in eelgrass (Zostera marina L.). Enrichment of seawater CO2 increased photosynthesis 3-fold, but had no long-term impact on respiration. By tripling the rate of light-saturated photosynthesis, CO2 enrichment reduced the daily period of irradiance-saturated photosynthesis (Hsat) that is required for the maintenance of positive whole-plant C balance from 7 to 2.7 h, allowing plants maintained under 4 h of Hsat to perform like plants growing in unenriched seawater with 12 h of Hsat. Eelgrass grown under 4 h of Hsat without added CO2 consumed internal C reserves as photosynthesis rates and chlorophyll levels dropped. Growth ceased after 30 d. Leaf photosynthesis, respiration, chlorophyll, and sucrose-phosphate synthase activity of CO2-enriched plants showed no acclimation to prolonged enrichment. Thus, the CO2-stimulated improvement in photosynthesis reduced light requirements in the long term, suggesting that globally increasing CO2 may enhance seagrass survival in eutrophic coastal waters, where populations have been devastated by algal proliferation and reduced water-column light transparency.

Saturable Absorption in 2D Ti3 C2 MXene Thin Films for Passive Photonic Diodes.

PubMed

Dong, Yongchang; Chertopalov, Sergii; Maleski, Kathleen; Anasori, Babak; Hu, Longyu; Bhattacharya, Sriparna; Rao, Apparao M; Gogotsi, Yury; Mochalin, Vadym N; Podila, Ramakrishna

2018-03-01

MXenes comprise a new class of 2D transition metal carbides, nitrides, and carbonitrides that exhibit unique light-matter interactions. Recently, 2D Ti 3 CNT x (T x represents functional groups such as OH and F) was found to exhibit nonlinear saturable absorption (SA) or increased transmittance at higher light fluences, which is useful for mode locking in fiber-based femtosecond lasers. However, the fundamental origin and thickness dependence of SA behavior in MXenes remain to be understood. 2D Ti 3 C 2 T x thin films of different thicknesses are fabricated using an interfacial film formation technique to systematically study their nonlinear optical properties. Using the open aperture Z-scan method, it is found that the SA behavior in Ti 3 C 2 T x MXene arises from plasmon-induced increase in the ground state absorption at photon energies above the threshold for free carrier oscillations. The saturation fluence and modulation depth of Ti 3 C 2 T x MXene is observed to be dependent on the film thickness. Unlike other 2D materials, Ti 3 C 2 T x is found to show higher threshold for light-induced damage with up to 50% increase in nonlinear transmittance. Lastly, building on the SA behavior of Ti 3 C 2 T x MXenes, a Ti 3 C 2 T x MXene-based photonic diode that breaks time-reversal symmetry to achieve nonreciprocal transmission of nanosecond laser pulses is demonstrated. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High-entropy Alloys with High Saturation Magnetization, Electrical Resistivity, and Malleability

PubMed Central

Zhang, Yong; Zuo, TingTing; Cheng, YongQiang; Liaw, Peter K.

2013-01-01

Soft magnetic materials (SMMs) find important applications in a number of areas. The diverse requirements for these applications are often demanding and challenging for the design and fabrication of SMMs. Here we report a new class of FeCoNi(AlSi)x (0 ≤ x ≤ 0.8 in molar ratio) SMMs based on high-entropy alloys (HEAs). It is found that with the compositional and structural changes, the optimal balance of magnetic, electrical, and mechanical properties is achieved at x = 0.2, for which the combination of saturation magnetization (1.15 T), coercivity (1,400 A/m), electrical resistivity (69.5 μΩ·cm), yield strength (342 MPa), and strain without fracture (50%) makes the alloy an excellent SMM. Ab initio calculations are used to explain the high magnetic saturation of the present HEAs and the effects of compositional structures on magnetic characteristics. The HEA-based SMMs point to new directions in both the application of HEAs and the search for novel SMMs. PMID:23492734

Continuous, noninvasive, and localized microvascular tissue oximetry using visible light spectroscopy.

PubMed

Benaron, David A; Parachikov, Ilian H; Friedland, Shai; Soetikno, Roy; Brock-Utne, John; van der Starre, Peter J A; Nezhat, Camran; Terris, Martha K; Maxim, Peter G; Carson, Jeffrey J L; Razavi, Mahmood K; Gladstone, Hayes B; Fincher, Edgar F; Hsu, Christopher P; Clark, F Landon; Cheong, Wai-Fung; Duckworth, Joshua L; Stevenson, David K

2004-06-01

The authors evaluated the ability of visible light spectroscopy (VLS) oximetry to detect hypoxemia and ischemia in human and animal subjects. Unlike near-infrared spectroscopy or pulse oximetry (SpO2), VLS tissue oximetry uses shallow-penetrating visible light to measure microvascular hemoglobin oxygen saturation (StO2) in small, thin tissue volumes. In pigs, StO2 was measured in muscle and enteric mucosa during normoxia, hypoxemia (SpO2 = 40-96%), and ischemia (occlusion, arrest). In patients, StO2 was measured in skin, muscle, and oral/enteric mucosa during normoxia, hypoxemia (SpO2 = 60-99%), and ischemia (occlusion, compression, ventricular fibrillation). In pigs, normoxic StO2 was 71 +/- 4% (mean +/- SD), without differences between sites, and decreased during hypoxemia (muscle, 11 +/- 6%; P < 0.001) and ischemia (colon, 31 +/- 11%; P < 0.001). In patients, mean normoxic StO2 ranged from 68 to 77% at different sites (733 measures, 111 subjects); for each noninvasive site except skin, variance between subjects was low (e.g., colon, 69% +/- 4%, 40 subjects; buccal, 77% +/- 3%, 21 subjects). During hypoxemia, StO2 correlated with SpO2 (animals, r2 = 0.98; humans, r2 = 0.87). During ischemia, StO2 initially decreased at -1.3 +/- 0.2%/s and decreased to zero in 3-9 min (r2 = 0.94). Ischemia was distinguished from normoxia and hypoxemia by a widened pulse/VLS saturation difference (Delta < 30% during normoxia or hypoxemia vs. Delta > 35% during ischemia). VLS oximetry provides a continuous, noninvasive, and localized measurement of the StO2, sensitive to hypoxemia, regional, and global ischemia. The reproducible and narrow StO2 normal range for oral/enteric mucosa supports use of this site as an accessible and reliable reference point for the VLS monitoring of systemic flow.

Preference for point-light human biological motion in newborns: contribution of translational displacement.

PubMed

Bidet-Ildei, Christel; Kitromilides, Elenitsa; Orliaguet, Jean-Pierre; Pavlova, Marina; Gentaz, Edouard

2014-01-01

In human newborns, spontaneous visual preference for biological motion is reported to occur at birth, but the factors underpinning this preference are still in debate. Using a standard visual preferential looking paradigm, 4 experiments were carried out in 3-day-old human newborns to assess the influence of translational displacement on perception of human locomotion. Experiment 1 shows that human newborns prefer a point-light walker display representing human locomotion as if on a treadmill over random motion. However, no preference for biological movement is observed in Experiment 2 when both biological and random motion displays are presented with translational displacement. Experiments 3 and 4 show that newborns exhibit preference for translated biological motion (Experiment 3) and random motion (Experiment 4) displays over the same configurations moving without translation. These findings reveal that human newborns have a preference for the translational component of movement independently of the presence of biological kinematics. The outcome suggests that translation constitutes the first step in development of visual preference for biological motion. PsycINFO Database Record (c) 2014 APA, all rights reserved.

The distribution of saturated clusters in wetted granular materials

NASA Astrophysics Data System (ADS)

Li, Shuoqi; Hanaor, Dorian; Gan, Yixiang

2017-06-01

The hydro-mechanical behaviour of partially saturated granular materials is greatly influenced by the spatial and temporal distribution of liquid within the media. The aim of this paper is to characterise the distribution of saturated clusters in granular materials using an optical imaging method under different water drainage conditions. A saturated cluster is formed when a liquid phase fully occupies the pore space between solid grains in a localized region. The samples considered here were prepared by vibrating mono-sized glass beads to form closely packed assemblies in a rectangular container. A range of drainage conditions were applied to the specimen by tilting the container and employing different flow rates, and the liquid pressure was recorded at different positions in the experimental cell. The formation of saturated clusters during the liquid withdrawal processes is governed by three competing mechanisms arising from viscous, capillary, and gravitational forces. When the flow rate is sufficiently large and the gravity component is sufficiently small, the viscous force tends to destabilize the liquid front leading to the formation of narrow fingers of saturated material. As the water channels along these liquid fingers break, saturated clusters are formed inside the specimen. Subsequently, a spatial and temporal distribution of saturated clusters can be observed. We investigated the resulting saturated cluster distribution as a function of flow rate and gravity to achieve a fundamental understanding of the formation and evolution of such clusters in partially saturated granular materials. This study serves as a bridge between pore-scale behavior and the overall hydro-mechanical characteristics in partially saturated soils.

Streaming Potential In Rocks Saturated With Water And Oil

NASA Astrophysics Data System (ADS)

Tarvin, J. A.; Caston, A.

2011-12-01

Fluids flowing through porous media generate electrical currents. These currents cause electric potentials, called "streaming potentials." Streaming potential amplitude depends on the applied pressure gradient, on rock and fluid properties, and on the interaction between rock and fluid. Streaming potential has been measured for rocks saturated with water (1) and with water-gas mixtures. (2) Few measurements (3) have been reported for rocks saturated with water-oil mixtures. We measured streaming potential for sandstone and limestone saturated with a mixture of brine and laboratory oil. Cylindrical samples were initially saturated with brine and submerged in oil. Saturation was changed by pumping oil from one end of a sample to the other and then through the sample in the opposite direction. Saturation was estimated from sample resistivity. The final saturation of each sample was determined by heating the sample in a closed container and measuring the pressure. Measurements were made by modulating the pressure difference (of oil) between the ends of a sample at multiple frequencies below 20 Hz. The observed streaming potential is a weak function of the saturation. Since sample conductivity decreases with increasing oil saturation, the electro-kinetic coupling coefficient (Pride's L (4)) decreases with increasing oil saturation. (1) David B. Pengra and Po-zen Wong, Colloids and Surfaces, vol., p. 159 283-292 (1999). (2) Eve S. Sprunt, Tony B. Mercer, and Nizar F. Djabbarah, Geophysics, vol. 59, p. 707-711 (1994). (3) Vinogradov, J., Jackson, M.D., Geophysical Res. L., Vol. 38, Article L01301 (2011). (4) Steve Pride, Phys. Rev. B, vol. 50, pp. 15678-15696 (1994).

Seagrass canopy photosynthetic response is a function of canopy density and light environment: a model for Amphibolis griffithii.

PubMed

Hedley, John D; McMahon, Kathryn; Fearns, Peter

2014-01-01

A three-dimensional computer model of canopies of the seagrass Amphibolis griffithii was used to investigate the consequences of variations in canopy structure and benthic light environment on leaf-level photosynthetic saturation state. The model was constructed using empirical data of plant morphometrics from a previously conducted shading experiment and validated well to in-situ data on light attenuation in canopies of different densities. Using published values of the leaf-level saturating irradiance for photosynthesis, results show that the interaction of canopy density and canopy-scale photosynthetic response is complex and non-linear, due to the combination of self-shading and the non-linearity of photosynthesis versus irradiance (P-I) curves near saturating irradiance. Therefore studies of light limitation in seagrasses should consider variation in canopy structure and density. Based on empirical work, we propose a number of possible measures for canopy scale photosynthetic response that can be plotted to yield isoclines in the space of canopy density and light environment. These plots can be used to interpret the significance of canopy changes induced as a response to decreases in the benthic light environment: in some cases canopy thinning can lead to an equivalent leaf level light environment, in others physiological changes may also be required but these alone may be inadequate for canopy survival. By providing insight to these processes the methods developed here could be a valuable management tool for seagrass conservation during dredging or other coastal developments.

Seagrass Canopy Photosynthetic Response Is a Function of Canopy Density and Light Environment: A Model for Amphibolis griffithii

PubMed Central

Hedley, John D.; McMahon, Kathryn; Fearns, Peter

2014-01-01

A three-dimensional computer model of canopies of the seagrass Amphibolis griffithii was used to investigate the consequences of variations in canopy structure and benthic light environment on leaf-level photosynthetic saturation state. The model was constructed using empirical data of plant morphometrics from a previously conducted shading experiment and validated well to in-situ data on light attenuation in canopies of different densities. Using published values of the leaf-level saturating irradiance for photosynthesis, results show that the interaction of canopy density and canopy-scale photosynthetic response is complex and non-linear, due to the combination of self-shading and the non-linearity of photosynthesis versus irradiance (P-I) curves near saturating irradiance. Therefore studies of light limitation in seagrasses should consider variation in canopy structure and density. Based on empirical work, we propose a number of possible measures for canopy scale photosynthetic response that can be plotted to yield isoclines in the space of canopy density and light environment. These plots can be used to interpret the significance of canopy changes induced as a response to decreases in the benthic light environment: in some cases canopy thinning can lead to an equivalent leaf level light environment, in others physiological changes may also be required but these alone may be inadequate for canopy survival. By providing insight to these processes the methods developed here could be a valuable management tool for seagrass conservation during dredging or other coastal developments. PMID:25347849

Patterns in tropical seagrass photosynthesis in relation to light, depth and habitat

NASA Astrophysics Data System (ADS)

Campbell, Stuart J.; McKenzie, Len J.; Kerville, Simon P.; Bité, Juanita S.

2007-07-01

Seagrass meadows across north-eastern Australia, survive a range of environmental conditions in coastal bays, reefs, estuarine and deepwater habitats through adaptation of a range of structural, morphological and physiological features. The aim of this study was to investigate the influence of spatial features (habitat type, site and depth) and photon flux on the photosynthetic performance of 11 tropical seagrass species. Pulse amplitude modulated (PAM) fluorometry was used to generate rapid light curves from which measures of maximal electron transport rate (ETR max), photosynthetic efficiency ( α), saturating irradiance ( Ek) and effective quantum yield (Δ F/ Fm') were derived. The amount of light absorbed by leaves (absorption factor) was also determined for each population. In intertidal habitats many seagrass species exhibited typical sun-type responses with a close coupling of both ETR max and Ek with photon flux. Photosynthetic performance ranged from minima in Thalassodendron ciliatum to maxima in Syringodium isoetifolium. The absence of a coupling between photosynthetic performance and photon flux in subtidal populations was most likely due to highly variable light climates and possible light attenuation, and hence the photo-biology of estuarine and deepwater seagrasses exhibited photosynthetic responses indicative of light limitation. In contrast seagrass species from shallow reef and coastal habitats for the most part exhibited light saturation characteristics. Of all the variables examined ETR max, Ek and Δ F/ Fm' were most responsive to changing light climates and provide reliable physiological indicators of real-time photosynthetic performance of tropical seagrasses under different light conditions.

A new adaptive light beam focusing principle for scanning light stimulation systems.

PubMed

Bitzer, L A; Meseth, M; Benson, N; Schmechel, R

2013-02-01

In this article a novel principle to achieve optimal focusing conditions or rather the smallest possible beam diameter for scanning light stimulation systems is presented. It is based on the following methodology: First, a reference point on a camera sensor is introduced where optimal focusing conditions are adjusted and the distance between the light focusing optic and the reference point is determined using a laser displacement sensor. In a second step, this displacement sensor is used to map the topography of the sample under investigation. Finally, the actual measurement is conducted, using optimal focusing conditions in each measurement point at the sample surface, that are determined by the height difference between camera sensor and the sample topography. This principle is independent of the measurement values, the optical or electrical properties of the sample, the used light source, or the selected wavelength. Furthermore, the samples can be tilted, rough, bent, or of different surface materials. In the following the principle is implemented using an optical beam induced current system, but basically it can be applied to any other scanning light stimulation system. Measurements to demonstrate its operation are shown, using a polycrystalline silicon solar cell.

An algorithm for sensing venous oxygenation using ultrasound-modulated light enhanced by microbubbles

NASA Astrophysics Data System (ADS)

Honeysett, Jack E.; Stride, Eleanor; Deng, Jing; Leung, Terence S.

2012-02-01

Near-infrared spectroscopy (NIRS) can provide an estimate of the mean oxygen saturation in tissue. This technique is limited by optical scattering, which reduces the spatial resolution of the measurement, and by absorption, which makes the measurement insensitive to oxygenation changes in larger deep blood vessels relative to that in the superficial tissue. Acousto-optic (AO) techniques which combine focused ultrasound (US) with diffuse light have been shown to improve the spatial resolution as a result of US-modulation of the light signal, however this technique still suffers from low signal-to-noise when detecting a signal from regions of high optical absorption. Combining an US contrast agent with this hybrid technique has been proposed to amplify an AO signal. Microbubbles are a clinical contrast agent used in diagnostic US for their ability to resonate in a sound field: in this work we also make use of their optical scattering properties (modelled using Mie theory). A perturbation Monte Carlo (pMC) model of light transport in a highly absorbing blood vessel containing microbubbles surrounded by tissue is used to calculate the AO signal detected on the top surface of the tissue. An algorithm based on the modified Beer-Lambert law is derived which expresses intravenous oxygen saturation in terms of an AO signal. This is used to determine the oxygen saturation in the blood vessel from a dual wavelength microbubble-contrast AO measurement. Applying this algorithm to the simulation data shows that the venous oxygen saturation is accurately recovered, and this measurement is robust to changes in the oxygenation of the superficial tissue layer.

Ultra-broadband nonlinear saturable absorption of high-yield MoS2 nanosheets

NASA Astrophysics Data System (ADS)

Wei, Rongfei; Zhang, Hang; Hu, Zhongliang; Qiao, Tian; He, Xin; Guo, Qiangbing; Tian, Xiangling; Chen, Zhi; Qiu, Jianrong

2016-07-01

High-yield MoS2 nanosheets with strong nonlinear optical (NLO) responses in a broad near-infrared range were synthesized by a facile hydrothermal method. The observation of saturable absorption, which was excited by the light with photon energy smaller than the gap energy of MoS2, can be attributed to the enhancement of the hybridization between the Mo d-orbital and S p-orbital by the oxygen incorporation into MoS2. High-yield MoS2 nanosheets with high modulation depth and large saturable intensity generated a stable, passively Q-switched fiber laser pulse at 1.56 μm. The high output power of 1.08 mW can be attained under a very low pump power of 30.87 mW. Compared to recently reported passively Q-switched fiber lasers utilizing exfoliated MoS2 nanosheets, the efficiency of the laser for our passive Q-switching operation is larger and reaches 3.50%. This research may extend the understanding on the NLO properties of MoS2 and indicate the feasibility of the high-yield MoS2 nanosheets to passively Q-switched fiber laser effectively at low pump strengths.

Estimation of dew point temperature using neuro-fuzzy and neural network techniques

NASA Astrophysics Data System (ADS)

Kisi, Ozgur; Kim, Sungwon; Shiri, Jalal

2013-11-01

This study investigates the ability of two different artificial neural network (ANN) models, generalized regression neural networks model (GRNNM) and Kohonen self-organizing feature maps neural networks model (KSOFM), and two different adaptive neural fuzzy inference system (ANFIS) models, ANFIS model with sub-clustering identification (ANFIS-SC) and ANFIS model with grid partitioning identification (ANFIS-GP), for estimating daily dew point temperature. The climatic data that consisted of 8 years of daily records of air temperature, sunshine hours, wind speed, saturation vapor pressure, relative humidity, and dew point temperature from three weather stations, Daego, Pohang, and Ulsan, in South Korea were used in the study. The estimates of ANN and ANFIS models were compared according to the three different statistics, root mean square errors, mean absolute errors, and determination coefficient. Comparison results revealed that the ANFIS-SC, ANFIS-GP, and GRNNM models showed almost the same accuracy and they performed better than the KSOFM model. Results also indicated that the sunshine hours, wind speed, and saturation vapor pressure have little effect on dew point temperature. It was found that the dew point temperature could be successfully estimated by using T mean and R H variables.

Thermal conductivity of water-saturated rocks from the KTB pilot hole at temperatures of 25 to 300°C

USGS Publications Warehouse

Pribnow, D.; Williams, C.F.; Sass, J.H.; Keating, R.

1996-01-01

The conductivitites of selected gneiss (two) and amphibolite (one) core samples have been measured under conditions of elevated temperature and pressure with a needle-probe. Water-saturated thermal conductivity measurements spanning temperatures from 25 to 300??C and hydrostatic pressures of 0.1 and 34 MPa confirm the general decrease in conductivity with increasing temperature but deviate significantly from results reported from measurements on dry samples over the same temperature range. The thermal conductivity of water-saturated amphibolite decreases with temperature at a rate approximately 40% less than the rate for dry amphibolite, and the conductivity of water-saturated gneiss decreases at a rate approximately 20% less than the rate for dry gneiss. The available evidence points to thermal cracking as the primary cause of the more rapid decrease in dry thermal conductivity with temperature. The effects of thermal cracking were also observed in the water-saturated samples but resulted in a net decrease in room-temperature conductivity of less than 3%. These results highlight the importance of duplicating in-situ conditions when determining thermal conductivity for the deep crust.

Light-operated proximity detector with linear output

DOEpatents

Simpson, M.L.; McNeilly, D.R.

1984-01-01

A light-operated proximity detector is described in which reflected light intensity from a surface whose proximity to the detector is to be gauged is translated directly into a signal proportional to the distance of the detector from the surface. A phototransistor is used to sense the reflected light and is connected in a detector circuit which maintains the phtotransistor in a saturated state. A negative feedback arrangement using an operational amplifier connected between the collector and emitter of the transistor provides an output at the output of the amplifier which is linearly proportional to the proximity of the surface to the detector containing the transistor. This direct proportional conversion is true even though the light intensity is varying with the proximity in proportion to the square of the inverse of the distance. The detector may be used for measuring the distance remotely from any target surface.

Light-operated proximity detector with linear output

DOEpatents

Simpson, Marc L.; McNeilly, David R.

1985-01-01

A light-operated proximity detector is described in which reflected light intensity from a surface whose proximity to the detector is to be gauged is translated directly into a signal proportional to the distance of the detector from the surface. A phototransistor is used to sense the reflected light and is connected in a detector circuit which maintains the phototransistor in a saturated state. A negative feedback arrangement using an operational amplifier connected between the collector and emitter of the transistor provides an output at the output of the amplifier which is linearly proportional to the proximity of the surface to the detector containing the transistor. This direct proportional conversion is true even though the light intensity is varying with the proximity in proportion to the square of the inverse of the distance. The detector may be used for measuring the distance remotely from any target surface.

Three-peak standard white organic light-emitting devices for solid-state lighting

NASA Astrophysics Data System (ADS)

Guo, Kunping; Wei, Bin

2014-12-01

Standard white organic light-emitting device (OLED) lighting provides a warm and comfortable atmosphere and shows mild effect on melatonin suppression. A high-efficiency red OLED employing phosphorescent dopant has been investigated. The device generates saturated red emission with Commission Internationale de l'Eclairage (CIE) coordinates of (0.66, 0.34), characterized by a low driving voltage of 3.5 V and high external quantum efficiency of 20.1% at 130 cd m-2. In addition, we have demonstrated a two-peak cold white OLED by combining with a pure blue emitter with the electroluminescent emission of 464 nm, 6, 12-bis{[N-(3,4-dimethylpheyl)-N-(2,4,5-trimethylphenyl)]} chrysene (BmPAC). It was found that the man-made lighting device capable of yielding a relatively stable color emission within the luminance range of 1000-5000 cd m-2. And the chromaticity coordinates, varying from (0.25, 0.21) to (0.23, 0.21). Furthermore, an ultrathin layer of green-light-emitting tris (2-phenylpyridinato)iridium(Ⅲ) Ir(ppy)3 in the host material was introduced to the emissive region for compensating light. By appropriately controlling the layer thickness, the white light OLED achieved good performance of 1280 cd m-2 at 5.0 V and 5150 cd m-2 at 7.0 V, respectively. The CIE coordinates of the emitted light are quite stable at current densities from 759 cd m-2 to 5150 cd m-2, ranging from (0.34, 0.37) to (0.33, 0.33).

Relationship between P-wave attenuation and water saturation in an homogeneous unconsolidated and partially saturated porous media : An experimental study

NASA Astrophysics Data System (ADS)

Barrière, J.; Sénéchal, P.; Bordes, C.; Perroud, H.

2010-12-01

Nowadays, it is well known that hydrogeological properties of the porous media (porosity, fluid saturation and permeability) can influence seismic properties. The major theory which links hydrogeological and seismic parameters is poroelasticity proposed by Biot (1956) for saturated porous media in a wetting phase fluid. However the Biot relaxation process can't explain the level of attenuation of seismic waves generally measured on field from seismic to sonic frequency range in the case of partially saturated media. Laboratory experiments are necessary to better understand the effects of fluids on the attenuation of waves but few ones are done in the low frequency range (1Hz to 10 kHz) where the wavelength is greater than heterogeneities size. We propose an experimental study to determine the attenuation of propagative P-wave in the sonic frequency range on unconsolidated and partially saturated porous media, typical of near surface hydrogeological media. 10 accelerometers (0.0001-17kHz) and 6 capacitance probes (soil moisture sensors) are placed in a container (107 cm x 34 cm x 35cm) full of homogeneous sand (99% silica). An acoustic source (0 - 20 kHz) generate seismic waves which are recorded by the accelerometers during three cycles of imbibition-drainage (corresponding to a water saturation range from 0% to 95%). Values of attenuation (quality factor Q) versus water saturation and frequency are calculated with the well-known spectral ratio method. The spectrum of each recorded P-wave is obtained by a continuous wavelet transform, more adapted than Fourier transform for a non-stationary signal, such as seismic signal, whose frequency content varies with time. The first analyses show a strong dependence of the quality factor with frequency and water saturation, notably at high water saturation (above 60 %) where the attenuation is maximum. Knowing some important parameters of the studied media such as porosity and permeability, we interpret physically our

Retinal oxygen saturation before and after glaucoma surgery.

PubMed

Nitta, Eri; Hirooka, Kazuyuki; Shimazaki, Takeru; Sato, Shino; Ukegawa, Kaori; Nakano, Yuki; Tsujikawa, Akitaka

2017-08-01

This study compared retinal vessel oxygen saturation before and after glaucoma surgery. Retinal oxygen saturation in glaucoma patients was measured using a non-invasive spectrophotometric retinal oximeter. Adequate image quality was found in 49 of the 108 consecutive glaucoma patients recruited, with 30 undergoing trabeculectomy, 11 EX-PRESS and eight trabeculotomy. Retinal oxygen saturation measurements in the retinal arterioles and venules were performed at 1 day prior to and at approximately 10 days after surgery. Statistical analysis was performed using a Student's t-test. After glaucoma surgery, intraocular pressure (IOP) decreased from 19.8 ± 7.7 mmHg to 9.0 ± 5.7 mmHg (p < 0.001). Although oxygen saturation in retinal arterioles remained unchanged before and after surgery (104.7 ± 10.6% before and 105.4 ± 9.3% after surgery, p = 0.58), the oxygen saturation in the venules increased from 54.9 ± 7.4% to 57.4 ± 5.7% (p = 0.01). Intraocular pressure (IOP) decreases caused by glaucoma surgery had an effect on the retinal venous oxygen saturation. © 2016 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

PRO-QUEST: a rapid assessment method based on progressive saturation for quantifying exchange rates using saturation times in CEST.

PubMed

Demetriou, Eleni; Tachrount, Mohamed; Zaiss, Moritz; Shmueli, Karin; Golay, Xavier

2018-03-05

To develop a new MRI technique to rapidly measure exchange rates in CEST MRI. A novel pulse sequence for measuring chemical exchange rates through a progressive saturation recovery process, called PRO-QUEST (progressive saturation for quantifying exchange rates using saturation times), has been developed. Using this method, the water magnetization is sampled under non-steady-state conditions, and off-resonance saturation is interleaved with the acquisition of images obtained through a Look-Locker type of acquisition. A complete theoretical framework has been set up, and simple equations to obtain the exchange rates have been derived. A reduction of scan time from 58 to 16 minutes has been obtained using PRO-QUEST versus the standard QUEST. Maps of both T 1 of water and B 1 can simply be obtained by repetition of the sequence without off-resonance saturation pulses. Simulations and calculated exchange rates from experimental data using amino acids such as glutamate, glutamine, taurine, and alanine were compared and found to be in good agreement. The PRO-QUEST sequence was also applied on healthy and infarcted rats after 24 hours, and revealed that imaging specificity to ischemic acidification during stroke was substantially increased relative to standard amide proton transfer-weighted imaging. Because of the reduced scan time and insensitivity to nonchemical exchange factors such as direct water saturation, PRO-QUEST can serve as an excellent alternative for researchers and clinicians interested to map pH changes in vivo. © 2018 International Society for Magnetic Resonance in Medicine.

False positive rate of carbon monoxide saturation by pulse oximetry of emergency department patients.

PubMed

Weaver, Lindell K; Churchill, Susan K; Deru, Kayla; Cooney, Darryl

2013-02-01

Symptoms of carbon monoxide (CO) poisoning are non-specific. Diagnosis requires suspicion of exposure, confirmed by measuring ambient CO levels or carboxyhemoglobin (COHb). An FDA-approved pulse oximeter (Rad-57) can measure CO saturation (S(pCO)). The device accuracy has implications for clinical decision-making. From April 1 to August 15, 2008, study personnel measured S(pCO) and documented demographic factors at time of clinical blood draw, in a convenience sample of 1,363 subjects presenting to the emergency department at Intermountain Medical Center, Murray, Utah. The technician then assayed COHb. COHb and S(pCO) values were compared by subject; false positive or negative values were defined as S(pCO) at least 3 percentage points greater or less than COHb level, reported by the manufacturer to be ± 1 SD in performance. In 1,363 subjects, 613 (45%) were male, 1,141 (84%) were light-skinned, 14 in shock, 4 with CO poisoning, and 122 (9%) met the criteria for a false positive value (range 3-19 percentage points), while 247 (18%) met the criteria for a false negative value (-13 to -3 percentage points). Risks for a false positive S(pCO) reading included being female and having a lower perfusion index. Methemoglobin, body temperature, and blood pressure also appear to influence the S(pCO) accuracy. There was variability among monitors, possibly related to technician technique, as rotation of monitors among technicians was not enforced. While the Rad-57 pulse oximeter functioned within the manufacturer's specifications, clinicians using the Rad-57 should expect some S(pCO) readings to be significantly higher or lower than COHb measurements, and should not use S(pCO) to direct triage or patient management. An elevated S(pCO) could broaden the diagnosis of CO poisoning in patients with non-specific symptoms. However, a negative S(pCO) level in patients suspected of having CO poisoning should never rule out CO poisoning, and should always be confirmed by COHb. © 2013

Onset and saturation of backward stimulated Raman scattering of laser in trapping regime in three spatial dimensions

NASA Astrophysics Data System (ADS)

Yin, L.; Albright, B. J.; Rose, H. A.; Bowers, K. J.; Bergen, B.; Montgomery, D. S.; Kline, J. L.; Fernández, J. C.

2009-11-01

A suite of three-dimensional (3D) VPIC [K. J. Bowers et al., Phys. Plasmas 15, 055703 (2008)] particle-in-cell simulations of backward stimulated Raman scattering (SRS) in inertial confinement fusion hohlraum plasma has been performed on the heterogeneous multicore supercomputer, Roadrunner, presently the world's most powerful supercomputer. These calculations reveal the complex nonlinear behavior of SRS and point to a new era of "at scale" 3D modeling of SRS in solitary and multiple laser speckles. The physics governing nonlinear saturation of SRS in a laser speckle in 3D is consistent with that of prior two-dimensional (2D) studies [L. Yin et al., Phys. Rev. Lett. 99, 265004 (2007)], but with important differences arising from enhanced diffraction and side loss in 3D compared with 2D. In addition to wave front bowing of electron plasma waves (EPWs) due to trapped electron nonlinear frequency shift and amplitude-dependent damping, we find for the first time that EPW self-focusing, which evolved from trapped particle modulational instability [H. A. Rose and L. Yin, Phys. Plasmas 15, 042311 (2008)], also exhibits loss of angular coherence by formation of a filament necklace, a process not available in 2D. These processes in 2D and 3D increase the side-loss rate of trapped electrons, increase wave damping, decrease source coherence for backscattered light, and fundamentally limit how much backscatter can occur from a laser speckle. For both SRS onset and saturation, the nonlinear trapping induced physics is not captured in linear gain modeling of SRS. A simple metric is described for using single-speckle reflectivities obtained from VPIC simulations to infer the total reflectivity from the population of laser speckles of amplitude sufficient for significant trapping-induced nonlinearity to arise.

Influences of rich in saturated and unsaturated fatty acids diets in rat myocardium.

PubMed

Pinotti, Matheus Fécchio; Silva, Maeli Dal-Pai; Sugizaki, Mário Mateus; Novelli, Yeda Santana Diniz; Sant'ana, Lea Sílvia; Aragon, Flávio Ferrari; Padovani, Carlos Roberto; Novelli, Ethel Lourenzi Barbosa; Cicogna, Antonio Carlos

2007-03-01

To study the influence of saturated (SFA) and unsaturated fatty acid (UFA) rich diets on mechanical function, morphology and oxidative stress in rat myocardium. Male, 60-day-old Wistar rats were fed a control (n=8), a SFA (n=8), or a UFA-rich diet (n=8) for sixty days. Mechanical function was studied in isolated left ventricle papillary muscle under isometric and isotonic contractions, in basal conditions (1.25 mM calcium chloride) and after 5.2 mM calcium chloride and beta-adrenergic stimuli with 1.0 microM isoproterenol. Left ventricle fragments were used to study oxidative stress and morphology under light and electron microscopy. SFA and UFA-rich diets did not change myocardium mechanical function. Both diets caused oxidative stress, with high lipid hydroperoxide and low superoxide-dismutase concentrations. UFA rich diet decreased catalase expression and SFA rich diet decreased the amount of myocardial glutathione-peroxidase. Both diets promoted light ultrastructural injuries such as lipid deposits and cell membrane injuries. Results suggest that SFA and UFA rich diets do not alter isolated muscle mechanical function, but promote light myocardial morphological injuries and oxidative stress.

Saturation of the turbulent dynamo.

PubMed

Schober, J; Schleicher, D R G; Federrath, C; Bovino, S; Klessen, R S

2015-08-01

The origin of strong magnetic fields in the Universe can be explained by amplifying weak seed fields via turbulent motions on small spatial scales and subsequently transporting the magnetic energy to larger scales. This process is known as the turbulent dynamo and depends on the properties of turbulence, i.e., on the hydrodynamical Reynolds number and the compressibility of the gas, and on the magnetic diffusivity. While we know the growth rate of the magnetic energy in the linear regime, the saturation level, i.e., the ratio of magnetic energy to turbulent kinetic energy that can be reached, is not known from analytical calculations. In this paper we present a scale-dependent saturation model based on an effective turbulent resistivity which is determined by the turnover time scale of turbulent eddies and the magnetic energy density. The magnetic resistivity increases compared to the Spitzer value and the effective scale on which the magnetic energy spectrum is at its maximum moves to larger spatial scales. This process ends when the peak reaches a characteristic wave number k☆ which is determined by the critical magnetic Reynolds number. The saturation level of the dynamo also depends on the type of turbulence and differs for the limits of large and small magnetic Prandtl numbers Pm. With our model we find saturation levels between 43.8% and 1.3% for Pm≫1 and between 2.43% and 0.135% for Pm≪1, where the higher values refer to incompressible turbulence and the lower ones to highly compressible turbulence.

Novel fusion for hybrid optical/microcomputed tomography imaging based on natural light surface reconstruction and iterated closest point

NASA Astrophysics Data System (ADS)

Ning, Nannan; Tian, Jie; Liu, Xia; Deng, Kexin; Wu, Ping; Wang, Bo; Wang, Kun; Ma, Xibo

2014-02-01

In mathematics, optical molecular imaging including bioluminescence tomography (BLT), fluorescence tomography (FMT) and Cerenkov luminescence tomography (CLT) are concerned with a similar inverse source problem. They all involve the reconstruction of the 3D location of a single/multiple internal luminescent/fluorescent sources based on 3D surface flux distribution. To achieve that, an accurate fusion between 2D luminescent/fluorescent images and 3D structural images that may be acquired form micro-CT, MRI or beam scanning is extremely critical. However, the absence of a universal method that can effectively convert 2D optical information into 3D makes the accurate fusion challengeable. In this study, to improve the fusion accuracy, a new fusion method for dual-modality tomography (luminescence/fluorescence and micro-CT) based on natural light surface reconstruction (NLSR) and iterated closest point (ICP) was presented. It consisted of Octree structure, exact visual hull from marching cubes and ICP. Different from conventional limited projection methods, it is 360° free-space registration, and utilizes more luminescence/fluorescence distribution information from unlimited multi-orientation 2D optical images. A mouse mimicking phantom (one XPM-2 Phantom Light Source, XENOGEN Corporation) and an in-vivo BALB/C mouse with implanted one luminescent light source were used to evaluate the performance of the new fusion method. Compared with conventional fusion methods, the average error of preset markers was improved by 0.3 and 0.2 pixels from the new method, respectively. After running the same 3D internal light source reconstruction algorithm of the BALB/C mouse, the distance error between the actual and reconstructed internal source was decreased by 0.19 mm.

Classification by Using Multispectral Point Cloud Data

NASA Astrophysics Data System (ADS)

Liao, C. T.; Huang, H. H.

2012-07-01

Remote sensing images are generally recorded in two-dimensional format containing multispectral information. Also, the semantic information is clearly visualized, which ground features can be better recognized and classified via supervised or unsupervised classification methods easily. Nevertheless, the shortcomings of multispectral images are highly depending on light conditions, and classification results lack of three-dimensional semantic information. On the other hand, LiDAR has become a main technology for acquiring high accuracy point cloud data. The advantages of LiDAR are high data acquisition rate, independent of light conditions and can directly produce three-dimensional coordinates. However, comparing with multispectral images, the disadvantage is multispectral information shortage, which remains a challenge in ground feature classification through massive point cloud data. Consequently, by combining the advantages of both LiDAR and multispectral images, point cloud data with three-dimensional coordinates and multispectral information can produce a integrate solution for point cloud classification. Therefore, this research acquires visible light and near infrared images, via close range photogrammetry, by matching images automatically through free online service for multispectral point cloud generation. Then, one can use three-dimensional affine coordinate transformation to compare the data increment. At last, the given threshold of height and color information is set as threshold in classification.

Comparison of the A-Cc curve fitting methods in determining maximum ribulose 1.5-bisphosphate carboxylase/oxygenase carboxylation rate, potential light saturated electron transport rate and leaf dark respiration.

PubMed

Miao, Zewei; Xu, Ming; Lathrop, Richard G; Wang, Yufei

2009-02-01

A review of the literature revealed that a variety of methods are currently used for fitting net assimilation of CO2-chloroplastic CO2 concentration (A-Cc) curves, resulting in considerable differences in estimating the A-Cc parameters [including maximum ribulose 1.5-bisphosphate carboxylase/oxygenase (Rubisco) carboxylation rate (Vcmax), potential light saturated electron transport rate (Jmax), leaf dark respiration in the light (Rd), mesophyll conductance (gm) and triose-phosphate utilization (TPU)]. In this paper, we examined the impacts of fitting methods on the estimations of Vcmax, Jmax, TPU, Rd and gm using grid search and non-linear fitting techniques. Our results suggested that the fitting methods significantly affected the predictions of Rubisco-limited (Ac), ribulose 1,5-bisphosphate-limited (Aj) and TPU-limited (Ap) curves and leaf photosynthesis velocities because of the inconsistent estimate of Vcmax, Jmax, TPU, Rd and gm, but they barely influenced the Jmax : Vcmax, Vcmax : Rd and Jmax : TPU ratio. In terms of fitting accuracy, simplicity of fitting procedures and sample size requirement, we recommend to combine grid search and non-linear techniques to directly and simultaneously fit Vcmax, Jmax, TPU, Rd and gm with the whole A-Cc curve in contrast to the conventional method, which fits Vcmax, Rd or gm first and then solves for Vcmax, Jmax and/or TPU with V(cmax), Rd and/or gm held as constants.

Optical imaging of hemoglobin oxygen saturation using a small number of spectral images for endoscopic application.

PubMed

Saito, Takaaki; Yamaguchi, Hiroshi

2015-01-01

Tissue hypoxia is associated with tumor and inflammatory diseases, and detection of hypoxia is potentially useful for their detailed diagnosis. An endoscope system that can optically observe hemoglobin oxygen saturation (StO2) would enable minimally invasive, real-time detection of lesion hypoxia in vivo. Currently, point measurement of tissue StO2 via endoscopy is possible using the commercial fiber-optic oximeter T-Stat, which is based on visible light spectroscopy at many wavelengths. For clinical use, however, imaging of StO2 is desirable to assess the distribution of tissue oxygenation around a lesion. Here, we describe our StO2 imaging technique based on a small number of wavelength ranges in the visible range. By assuming a homogeneous tissue, we demonstrated that tissue StO2 can be obtained independently from the scattering property and blood concentration of tissue using four spectral bands. We developed a prototype endoscope system and used it to observe tissue-simulating phantoms. The StO2 (%) values obtained using our technique agreed with those from the T-Stat within 10%. We also showed that tissue StO2 can be derived using three spectral band if the scattering property is fixed at preliminarily measured values.

Economical analysis of saturation mutagenesis experiments

PubMed Central

Acevedo-Rocha, Carlos G.; Reetz, Manfred T.; Nov, Yuval

2015-01-01

Saturation mutagenesis is a powerful technique for engineering proteins, metabolic pathways and genomes. In spite of its numerous applications, creating high-quality saturation mutagenesis libraries remains a challenge, as various experimental parameters influence in a complex manner the resulting diversity. We explore from the economical perspective various aspects of saturation mutagenesis library preparation: We introduce a cheaper and faster control for assessing library quality based on liquid media; analyze the role of primer purity and supplier in libraries with and without redundancy; compare library quality, yield, randomization efficiency, and annealing bias using traditional and emergent randomization schemes based on mixtures of mutagenic primers; and establish a methodology for choosing the most cost-effective randomization scheme given the screening costs and other experimental parameters. We show that by carefully considering these parameters, laboratory expenses can be significantly reduced. PMID:26190439

Artwork visualization using a solid-state lighting engine with controlled photochemical safety.

PubMed

Tuzikas, Arūnas; Žukauskas, Artūras; Vaicekauksas, Rimantas; Petrulis, Andrius; Vitta, Pranciškus; Shur, Michael

2014-07-14

A concept of a solid-state lighting engine for artwork-specific illumination with controlled photochemical safety is introduced. The engine is based on a tetrachromatic cluster of colored light-emitting diodes wirelessly controlled via an external smart device. By using an instantaneous dimming functionality, the driving software allows for maintaining the damage irradiance relevant to a particular type of photosensitive artwork material at a constant value, while varying the chromaticity and color rendition properties of the generated light. The effect of the constant damage irradiance on the visual impression from artworks is demonstrated for the lighting engine operating in three modes, such as selecting color temperature, tuning color saturating ability, and shifting chromaticity outside white light locus, respectively.

Influences of point defects on electrical and optical properties of InGaN light-emitting diodes at cryogenic temperature

NASA Astrophysics Data System (ADS)

Tu, Yi; Ruan, Yujiao; Zhu, Lihong; Tu, Qingzhen; Wang, Hongwei; Chen, Jie; Lu, Yijun; Gao, Yulin; Shih, Tien-Mo; Chen, Zhong; Lin, Yue

2018-04-01

We investigate the cryogenic external quantum efficiency (EQE) for some InGaN light-emitting diodes with different indium contents. We observe a monotonic decrease in EQE with the increasing forward current before the "U-turn" point, beyond which the thermal effect increases the EQE. We discover positive dependences among the droop rate (χ), differential electrical resistance (Rd), and indium content. Also, χ and Rd of individual green samples shift correspondingly during the aging test, when the Mg ions are activated at high injection density and diffuse into the active region. Considering the fact that both In and Mg ions would introduce point defects (PDs), we proposed a model that reveals the mechanism of interplay between PDs and carriers. PDs serve as both energy traps and non-radiative recombination centers. They attract and confine carriers, leading to an increase in Rd and a decrease in EQE.

Enhancing light-atom interactions via atomic bunching

NASA Astrophysics Data System (ADS)

Schmittberger, Bonnie L.; Gauthier, Daniel J.

2014-07-01

There is a broad interest in enhancing the strength of light-atom interactions to the point where injecting a single photon induces a nonlinear material response. Here we show theoretically that sub-Doppler-cooled two-level atoms that are spatially organized by weak optical fields give rise to a nonlinear material response that is greatly enhanced beyond that attainable in a homogeneous gas. Specifically, in the regime where the intensity of the applied optical fields is much less than the off-resonance saturation intensity, we show that the third-order nonlinear susceptibility scales inversely with atomic temperature and, due to this scaling, can be two orders of magnitude larger than that of a homogeneous gas for typical experimental parameters. As a result, we predict that spatially bunched two-level atoms can exhibit single-photon nonlinearities. Our model is valid for all regimes of atomic bunching and simultaneously accounts for the backaction of the atoms on the optical fields. Our results agree with previous theoretical and experimental results for light-atom interactions that have considered only limited regimes of atomic bunching. For lattice beams tuned to the low-frequency side of the atomic transition, we find that the nonlinearity transitions from a self-focusing type to a self-defocusing type at a critical intensity. We also show that higher than third-order nonlinear optical susceptibilities are significant in the regime where the dipole potential energy is on the order of the atomic thermal energy. We therefore find that it is crucial to retain high-order nonlinearities to accurately predict interactions of laser fields with spatially organized ultracold atoms. The model presented here is a foundation for modeling low-light-level nonlinear optical processes for ultracold atoms in optical lattices.

Seeking fixed points in multiple coupling scalar theories in the ɛ expansion

NASA Astrophysics Data System (ADS)

Osborn, Hugh; Stergiou, Andreas

2018-05-01

Fixed points for scalar theories in 4 - ɛ, 6 - ɛ and 3 - ɛ dimensions are discussed. It is shown how a large range of known fixed points for the four dimensional case can be obtained by using a general framework with two couplings. The original maximal symmetry, O( N), is broken to various subgroups, both discrete and continuous. A similar discussion is applied to the six dimensional case. Perturbative applications of the a-theorem are used to help classify potential fixed points. At lowest order in the ɛ-expansion it is shown that at fixed points there is a lower bound for a which is saturated at bifurcation points.

ATPase activity and light scattering of acto-heavy meromyosin: dependence on ATP concentration and on ionic strength.

PubMed

Dancker, P

1975-01-01

1. The dependence on ATP concentration of ATPase activity and light scattering decrease of acto-HMM could be described at very low ionic strength by one hyperbolic adsorption isotherm with a dissociation constant of 3 X 10(-6)M. Hence the increase of ATP ase activity was paralleled by a decrease in light scattering. At higher values of ionic strength ATPase activity stopped rising before HMM was completely saturated with ATP. Higher ionic strength prevented ATPase activity from further increasing when the rigor links (links between actin and nucleotide-free myosin), which have formerly protected the ATPase against the suppressing action of higher ionic strength have fallen below a certain amount. This protecting influence of rigor links did not require tropomyosin-troponin. 2. For complete activation of ATPase activity by actin less actin was needed when HMM was incompletely saturated with ATP than when it was completely saturated with ATP. 3. The apparent affinity of ATP to regulated acto-HMM (which contained tropomyosin-troponin) was lower than to unregulated acto-HMM (which was devoid of tropomyosin-troponin). In the presence of rigor complexes (indicated by an incomplete decrease of light scattering) the ATPase activity of regulated acto-HMM was higher than that of unregulated acto-HMM. At increasing ATP concentrations the ATPase activity of regulated acto-HMM stopped rising at a similar degree of saturation with ATP as the ATPase activity of unregulated acto-HMM at the same ionic strength.

Analysis of energy efficient highway lighting retrofits.

DOT National Transportation Integrated Search

2015-06-01

Solid state lighting technology is advancing rapidly to a point where light emitting diode (LED) lighting : systems can be viable replacements for existing lighting systems using high pressure sodium (HPS). The : present report summarizes analyses co...

The saturable absorption and reverse saturable absorption properties of Cu doped zinc oxide thin films

NASA Astrophysics Data System (ADS)

Yao, Cheng-Bao; Wen, Xin; Li, Qiang-Hua; Yan, Xiao-Yan; Li, Jin; Zhang, Ke-Xin; Sun, Wen-Jun; Bai, Li-Na; Yang, Shou-Bin

2017-03-01

We present the structure and nonlinear absorption (NLA) properties of Cu-doped ZnO (CZO) films prepared by magnetron sputtering. The films were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The results show that the CZO films can maintain a wurtzite structure. Furthermore, the open-aperture (OA) Z-scan measurements of the film were carried out by nanosecond laser pulse. A transition from saturable absorption (SA) to reverse saturable absorption (RSA) was observed as the excitation intensity increasing. With good excellent nonlinear optical coefficient, the samples were expected to be the potential applications in optical devices.

Biodegradation of crude oil saturated fraction supported on clays.

PubMed

Ugochukwu, Uzochukwu C; Jones, Martin D; Head, Ian M; Manning, David A C; Fialips, Claire I

2014-02-01

The role of clay minerals in crude oil saturated hydrocarbon removal during biodegradation was investigated in aqueous clay/saturated hydrocarbon microcosm experiments with a hydrocarbon degrading microorganism community. The clay minerals used for this study were montmorillonite, palygorskite, saponite and kaolinite. The clay mineral samples were treated with hydrochloric acid and didecyldimethylammonium bromide to produce acid activated- and organoclays respectively which were used in this study. The production of organoclay was restricted to only montmorillonite and saponite because of their relative high CEC. The study indicated that acid activated clays, organoclays and unmodified kaolinite, were inhibitory to biodegradation of the hydrocarbon saturates. Unmodified saponite was neutral to biodegradation of the hydrocarbon saturates. However, unmodified palygorskite and montmorillonite were stimulatory to biodegradation of the hydrocarbon saturated fraction and appears to do so as a result of the clays' ability to provide high surface area for the accumulation of microbes and nutrients such that the nutrients were within the 'vicinity' of the microbes. Adsorption of the saturated hydrocarbons was not significant during biodegradation.

PFP Emergency Lighting Study

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

BUSCH, M.S.

2000-02-02

NFPA 101, section 5-9 mandates that, where required by building classification, all designated emergency egress routes be provided with adequate emergency lighting in the event of a normal lighting outage. Emergency lighting is to be arranged so that egress routes are illuminated to an average of 1.0 footcandle with a minimum at any point of 0.1 footcandle, as measured at floor level. These levels are permitted to drop to 60% of their original value over the required 90 minute emergency lighting duration after a power outage. The Plutonium Finishing Plant (PFP) has two designations for battery powered egress lights ''Emergencymore » Lights'' are those battery powered lights required by NFPA 101 to provide lighting along officially designated egress routes in those buildings meeting the correct occupancy requirements. Emergency Lights are maintained on a monthly basis by procedure ZSR-12N-001. ''Backup Lights'' are battery powered lights not required by NFPA, but installed in areas where additional light may be needed. The Backup Light locations were identified by PFP Safety and Engineering based on several factors. (1) General occupancy and type of work in the area. Areas occupied briefly during a shiftly surveillance do not require backup lighting while a room occupied fairly frequently or for significant lengths of time will need one or two Backup lights to provide general illumination of the egress points. (2) Complexity of the egress routes. Office spaces with a standard hallway/room configuration will not require Backup Lights while a large room with several subdivisions or irregularly placed rooms, doors, and equipment will require Backup Lights to make egress safer. (3) Reasonable balance between the safety benefits of additional lighting and the man-hours/exposure required for periodic light maintenance. In some plant areas such as building 236-Z, the additional maintenance time and risk of contamination do not warrant having Backup Lights installed in

Heat generation and light scattering of green fluorescent protein-like pigments in coral tissue

NASA Astrophysics Data System (ADS)

Lyndby, Niclas H.; Kühl, Michael; Wangpraseurt, Daniel

2016-05-01

Green fluorescent protein (GFP)-like pigments have been proposed to have beneficial effects on coral photobiology. Here, we investigated the relationships between green fluorescence, coral heating and tissue optics for the massive coral Dipsastraea sp. (previously Favia sp.). We used microsensors to measure tissue scalar irradiance and temperature along with hyperspectral imaging and combined imaging of variable chlorophyll fluorescence and green fluorescence. Green fluorescence correlated positively with coral heating and scalar irradiance enhancement at the tissue surface. Coral tissue heating saturated for maximal levels of green fluorescence. The action spectrum of coral surface heating revealed that heating was highest under red (peaking at 680 nm) irradiance. Scalar irradiance enhancement in coral tissue was highest when illuminated with blue light, but up to 62% (for the case of highest green fluorescence) of this photon enhancement was due to green fluorescence emission. We suggest that GFP-like pigments scatter the incident radiation, which enhances light absorption and heating of the coral. However, heating saturates, because intense light scattering reduces the vertical penetration depth through the tissue eventually leading to reduced light absorption at high fluorescent pigment density. We conclude that fluorescent pigments can have a central role in modulating coral light absorption and heating.

Spacing of bending-induced fractures at saturation: Numerical models and approximate analytical solution

NASA Astrophysics Data System (ADS)

Schöpfer, Martin; Lehner, Florian; Grasemann, Bernhard; Kaserer, Klemens; Hinsch, Ralph

2017-04-01

John G. Ramsay's sketch of structures developed in a layer progressively folded and deformed by tangential longitudinal strain (Figure 7-65 in Folding and Fracturing of Rocks) and the associated strain pattern analysis have been reproduced in many monographs on Structural Geology and are referred to in numerous publications. Although the origin of outer-arc extension fractures is well-understood and documented in many natural examples, geomechanical factors controlling their (finite or saturation) spacing are hitherto unexplored. This study investigates the formation of bending-induced fractures during constant-curvature forced folding using Distinct Element Method (DEM) numerical modelling. The DEM model comprises a central brittle layer embedded within weaker (low modulus) elastic layers; the layer interfaces are frictionless (free slip). Folding of this three-layer system is enforced by a velocity boundary condition at the model base, while a constant overburden pressure is maintained at the model top. The models illustrate several key stages of fracture array development: (i) Prior to the onset of fracture, the neutral surface is located midway between the layer boundaries; (ii) A first set of regularly spaced fractures develops once the tensile stress in the outer-arc equals the tensile strength of the layer. Since the layer boundaries are frictionless, these bending-induced fractures propagate through the entire layer; (iii) After the appearance of the first fracture set, the rate of fracture formation decreases rapidly and so-called infill fractures develop approximately midway between two existing fractures (sequential infilling); (iv) Eventually no new fractures form, irrespective of any further increase in fold curvature (fracture saturation). Analysis of the interfacial normal stress distributions suggests that at saturation the fracture-bound blocks are subjected to a loading condition similar to three-point bending. Using classical beam theory an

A new comparison method for dew-point generators

NASA Astrophysics Data System (ADS)

Heinonen, Martti

1999-12-01

A new method for comparing dew-point generators was developed at the Centre for Metrology and Accreditation. In this method, the generators participating in a comparison are compared with a transportable saturator unit using a dew-point comparator. The method was tested by constructing a test apparatus and by comparing it with the MIKES primary dew-point generator several times in the dew-point temperature range from -40 to +75 °C. The expanded uncertainty (k = 2) of the apparatus was estimated to be between 0.05 and 0.07 °C and the difference between the comparator system and the generator is well within these limits. In particular, all of the results obtained in the range below 0 °C are within ±0.03 °C. It is concluded that a new type of a transfer standard with characteristics most suitable for dew-point comparisons can be developed on the basis of the principles presented in this paper.

The densities of halite-saturated WIPP-A and NBT-6 brines and their NaCl contents in weight percent, molal, and molar units from 20 to 100 degrees C

USGS Publications Warehouse

Chou, I-Ming; Buizinga, B.; Clynne, M.A.; Potter, R.W.

1982-01-01

A series of density measurements has been performed at 30?, 50?, 70?, and 90?C for halite-undersaturated WIPP-A and NBT-6 brines with various NaCl contents approaching saturation. The densities of halite-saturated WIPP-A and NBT-6 brines were obtained by extrapolating these measured densities to halite saturation points. The maximum difference between the densities obtained in this Fashion and those calculated from the model of Potter and Haas is 0.015 g/cm3. The NaCl contents in halite-saturated WIPP-A and NBT-6 brines are reported in wt %, molal, and molar units from 20? to 100?C.

Biofilter design for effective nitrogen removal from stormwater - influence of plant species, inflow hydrology and use of a saturated zone.

PubMed

Payne, Emily G I; Pham, Tracey; Cook, Perran L M; Fletcher, Tim D; Hatt, Belinda E; Deletic, Ana

2014-01-01

The use of biofilters to remove nitrogen and other pollutants from urban stormwater runoff has demonstrated varied success across laboratory and field studies. Design variables including plant species and use of a saturated zone have large impacts upon performance. A laboratory column study of 22 plant species and designs with varied outlet configuration was conducted across a 1.5-year period to further investigate the mechanisms and influences driving biofilter nitrogen processing. This paper presents outflow concentrations of total nitrogen from two sampling events across both 'wet' and 'dry' frequency dosing, and from sampling across two points in the outflow hydrograph. All plant species were effective under conditions of frequent dosing, but extended drying increased variation between species and highlighted the importance of a saturated zone in maintaining biofilter function. The saturated zone also effectively treated the volume of stormwater stored between inflow events, but this extended detention provided no additional benefit alongside the rapid processing of the highest performing species. Hence, the saturated zone reduced performance differences between plant species, and potentially acts as an 'insurance policy' against poor sub-optimal plant selection. The study shows the importance of biodiversity and inclusion of a saturated zone in protecting against climate variability.

Elasticity of water-saturated rocks as a function of temperature and pressure.

NASA Technical Reports Server (NTRS)

Takeuchi, S.; Simmons, G.

1973-01-01

Compressional and shear wave velocities of water-saturated rocks were measured as a function of both pressure and temperature near the melting point of ice to confining pressure of 2 kb. The pore pressure was kept at about 1 bar before the water froze. The presence of a liquid phase (rather than ice) in microcracks of about 0.3% porosity affected the compressional wave velocity by about 5% and the shear wave velocity by about 10%. The calculated effective bulk modulus of the rocks changes rapidly over a narrow range of temperature near the melting point of ice, but the effective shear modulus changes gradually over a wider range of temperature. This phenomenon, termed elastic anomaly, is attributed to the existence of liquid on the boundary between rock and ice due to local stresses and anomalous melting of ice under pressure.

Sensorimotor Synchronization with Different Metrical Levels of Point-Light Dance Movements

PubMed Central

Su, Yi-Huang

2016-01-01

Rhythm perception and synchronization have been extensively investigated in the auditory domain, as they underlie means of human communication such as music and speech. Although recent studies suggest comparable mechanisms for synchronizing with periodically moving visual objects, the extent to which it applies to ecologically relevant information, such as the rhythm of complex biological motion, remains unknown. The present study addressed this issue by linking rhythm of music and dance in the framework of action-perception coupling. As a previous study showed that observers perceived multiple metrical periodicities in dance movements that embodied this structure, the present study examined whether sensorimotor synchronization (SMS) to dance movements resembles what is known of auditory SMS. Participants watched a point-light figure performing two basic steps of Swing dance cyclically, in which the trunk bounced at every beat and the limbs moved at every second beat, forming two metrical periodicities. Participants tapped synchronously to the bounce of the trunk with or without the limbs moving in the stimuli (Experiment 1), or tapped synchronously to the leg movements with or without the trunk bouncing simultaneously (Experiment 2). Results showed that, while synchronization with the bounce (lower-level pulse) was not influenced by the presence or absence of limb movements (metrical accent), synchronization with the legs (beat) was improved by the presence of the bounce (metrical subdivision) across different movement types. The latter finding parallels the “subdivision benefit” often demonstrated in auditory tasks, suggesting common sensorimotor mechanisms for visual rhythms in dance and auditory rhythms in music. PMID:27199709

Sensorimotor Synchronization with Different Metrical Levels of Point-Light Dance Movements.

PubMed

Su, Yi-Huang

2016-01-01

Rhythm perception and synchronization have been extensively investigated in the auditory domain, as they underlie means of human communication such as music and speech. Although recent studies suggest comparable mechanisms for synchronizing with periodically moving visual objects, the extent to which it applies to ecologically relevant information, such as the rhythm of complex biological motion, remains unknown. The present study addressed this issue by linking rhythm of music and dance in the framework of action-perception coupling. As a previous study showed that observers perceived multiple metrical periodicities in dance movements that embodied this structure, the present study examined whether sensorimotor synchronization (SMS) to dance movements resembles what is known of auditory SMS. Participants watched a point-light figure performing two basic steps of Swing dance cyclically, in which the trunk bounced at every beat and the limbs moved at every second beat, forming two metrical periodicities. Participants tapped synchronously to the bounce of the trunk with or without the limbs moving in the stimuli (Experiment 1), or tapped synchronously to the leg movements with or without the trunk bouncing simultaneously (Experiment 2). Results showed that, while synchronization with the bounce (lower-level pulse) was not influenced by the presence or absence of limb movements (metrical accent), synchronization with the legs (beat) was improved by the presence of the bounce (metrical subdivision) across different movement types. The latter finding parallels the "subdivision benefit" often demonstrated in auditory tasks, suggesting common sensorimotor mechanisms for visual rhythms in dance and auditory rhythms in music.

Reducing calories, fat, saturated fat and sodium in restaurant menu items: Effects on consumer acceptance

PubMed Central

Patel, Anjali A.; Lopez, Nanette V.; Lawless, Harry T.; Njike, Valentine; Beleche, Mariana; Katz, David L.

2016-01-01

OBJECTIVE This study assessed consumer acceptance of reductions of calories, fat, saturated fat, and sodium to current restaurant recipes. METHODS Twenty-four menu items, from six restaurant chains, were slightly modified and moderately modified by reducing targeted ingredients. Restaurant customers (n=1,838) were recruited for a taste test and were blinded to the recipe version as well as the purpose of the study. Overall consumer acceptance was measured using a 9-point hedonic (like/dislike) scale, likelihood to purchase scale, Just-About-Right (JAR) 5-point scale, penalty analysis and alienation analysis. RESULTS Overall, modified recipes of 19 menu items were scored similar to (or better than) their respective current versions. Eleven menu items were found to be acceptable at the slightly modified recipe version and eight menu items were found to be acceptable at the moderately modified recipe version. Acceptable ingredient reductions resulted in a reduction of up to 26% in calories and a reduction of up to 31% in sodium per serving. CONCLUSIONS The majority of restaurant menu items with small reductions of calories, fat, saturated fat and sodium were acceptable. Given the frequency of eating foods away from home, these reductions could be effective in creating dietary improvements for restaurant diners. PMID:27891828

Reducing calories, fat, saturated fat, and sodium in restaurant menu items: Effects on consumer acceptance.

PubMed

Patel, Anjali A; Lopez, Nanette V; Lawless, Harry T; Njike, Valentine; Beleche, Mariana; Katz, David L

2016-12-01

To assess consumer acceptance of reductions of calories, fat, saturated fat, and sodium to current restaurant recipes. Twenty-four menu items, from six restaurant chains, were slightly modified and moderately modified by reducing targeted ingredients. Restaurant customers (n = 1,838) were recruited for a taste test and were blinded to the recipe version as well as the purpose of the study. Overall consumer acceptance was measured using a 9-point hedonic (like/dislike) scale, likelihood to purchase scale, Just-About-Right (JAR) 5-point scale, penalty analysis, and alienation analysis. Overall, modified recipes of 19 menu items were scored similar to (or better than) their respective current versions. Eleven menu items were found to be acceptable in the slightly modified recipe version, and eight menu items were found to be acceptable in the moderately modified recipe version. Acceptable ingredient modifications resulted in a reduction of up to 26% in calories and a reduction of up to 31% in sodium per serving. The majority of restaurant menu items with small reductions of calories, fat, saturated fat, and sodium were acceptable. Given the frequency of eating foods away from home, these reductions could be effective in creating dietary improvements for restaurant diners. © 2016 The Obesity Society.

Resolution enhancement in deep-tissue nanoparticle imaging based on plasmonic saturated excitation microscopy

NASA Astrophysics Data System (ADS)

Deka, Gitanjal; Nishida, Kentaro; Mochizuki, Kentaro; Ding, Hou-Xian; Fujita, Katsumasa; Chu, Shi-Wei

2018-03-01

Recently, many resolution enhancing techniques are demonstrated, but most of them are severely limited for deep tissue applications. For example, wide-field based localization techniques lack the ability of optical sectioning, and structured light based techniques are susceptible to beam distortion due to scattering/aberration. Saturated excitation (SAX) microscopy, which relies on temporal modulation that is less affected when penetrating into tissues, should be the best candidate for deep-tissue resolution enhancement. Nevertheless, although fluorescence saturation has been successfully adopted in SAX, it is limited by photobleaching, and its practical resolution enhancement is less than two-fold. Recently, we demonstrated plasmonic SAX which provides bleaching-free imaging with three-fold resolution enhancement. Here we show that the three-fold resolution enhancement is sustained throughout the whole working distance of an objective, i.e., 200 μm, which is the deepest super-resolution record to our knowledge, and is expected to extend into deeper tissues. In addition, SAX offers the advantage of background-free imaging by rejecting unwanted scattering background from biological tissues. This study provides an inspirational direction toward deep-tissue super-resolution imaging and has the potential in tumor monitoring and beyond.

Patterning via optical saturable transitions

NASA Astrophysics Data System (ADS)

Cantu, Precious

For the past 40 years, optical lithography has been the patterning workhorse for the semiconductor industry. However, as integrated circuits have become more and more complex, and as device geometries shrink, more innovative methods are required to meet these needs. In the far-field, the smallest feature that can be generated with light is limited to approximately half the wavelength. This, so called far-field diffraction limit or the Abbe limit (after Prof. Ernst Abbe who first recognized this), effectively prevents the use of long-wavelength photons >300nm from patterning nanostructures <100nm. Even with a 193nm laser source and extremely complicated processing, patterns below ˜20nm are incredibly challenging to create. Sources with even shorter wavelengths can potentially be used. However, these tend be much more expensive and of much lower brightness, which in turn limits their patterning speed. Multi-photon reactions have been proposed to overcome the diffraction limit. However, these require very large intensities for modest gain in resolution. Moreover, the large intensities make it difficult to parallelize, thus limiting the patterning speed. In this dissertation, a novel nanopatterning technique using wavelength-selective small molecules that undergo single-photon reactions, enabling rapid top-down nanopatterning over large areas at low-light intensities, thereby allowing for the circumvention of the far-field diffraction barrier is developed and experimentally verified. This approach, which I refer to as Patterning via Optical Saturable Transitions (POST) has the potential for massive parallelism, enabling the creation of nanostructures and devices at a speed far surpassing what is currently possible with conventional optical lithographic techniques. The fundamental understanding of this technique goes beyond optical lithography in the semiconductor industry and is applicable to any area that requires the rapid patterning of large-area two or three

Hydrate morphology: Physical properties of sands with patchy hydrate saturation

USGS Publications Warehouse

Dai, S.; Santamarina, J.C.; Waite, William F.; Kneafsey, T.J.

2012-01-01

The physical properties of gas hydrate-bearing sediments depend on the volume fraction and spatial distribution of the hydrate phase. The host sediment grain size and the state of effective stress determine the hydrate morphology in sediments; this information can be used to significantly constrain estimates of the physical properties of hydrate-bearing sediments, including the coarse-grained sands subjected to high effective stress that are of interest as potential energy resources. Reported data and physical analyses suggest hydrate-bearing sands contain a heterogeneous, patchy hydrate distribution, whereby zones with 100% pore-space hydrate saturation are embedded in hydrate-free sand. Accounting for patchy rather than homogeneous hydrate distribution yields more tightly constrained estimates of physical properties in hydrate-bearing sands and captures observed physical-property dependencies on hydrate saturation. For example, numerical modeling results of sands with patchy saturation agree with experimental observation, showing a transition in stiffness starting near the series bound at low hydrate saturations but moving toward the parallel bound at high hydrate saturations. The hydrate-patch size itself impacts the physical properties of hydrate-bearing sediments; for example, at constant hydrate saturation, we find that conductivity (electrical, hydraulic and thermal) increases as the number of hydrate-saturated patches increases. This increase reflects the larger number of conductive flow paths that exist in specimens with many small hydrate-saturated patches in comparison to specimens in which a few large hydrate saturated patches can block flow over a significant cross-section of the specimen.

Seismic determination of saturation in fractured reservoirs

USGS Publications Warehouse

Brown, R.L.; Wiggins, M.L.; Gupta, A.

2002-01-01

Detecting the saturation of a fractured reservoir using shear waves is possible when the fractures have a geometry that induces a component of movement perpendicular to the fractures. When such geometry is present, vertically traveling shear waves can be used to examine the saturation of the fractured reservoir. Tilted, corrugated, and saw-tooth fracture models are potential examples.

Smooth muscle myosin light chain kinase efficiently phosphorylates serine 15 of cardiac myosin regulatory light chain

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

Josephson, Matthew P.; Sikkink, Laura A.; Penheiter, Alan R.

2011-12-16

Highlights: Black-Right-Pointing-Pointer Cardiac myosin regulatory light chain (MYL2) is phosphorylated at S15. Black-Right-Pointing-Pointer Smooth muscle myosin light chain kinase (smMLCK) is a ubiquitous kinase. Black-Right-Pointing-Pointer It is a widely believed that MYL2 is a poor substrate for smMLCK. Black-Right-Pointing-Pointer In fact, smMLCK efficiently and rapidly phosphorylates S15 in MYL2. Black-Right-Pointing-Pointer Phosphorylation kinetics measured by novel fluorescence method without radioactivity. -- Abstract: Specific phosphorylation of the human ventricular cardiac myosin regulatory light chain (MYL2) modifies the protein at S15. This modification affects MYL2 secondary structure and modulates the Ca{sup 2+} sensitivity of contraction in cardiac tissue. Smooth muscle myosin light chainmore » kinase (smMLCK) is a ubiquitous kinase prevalent in uterus and present in other contracting tissues including cardiac muscle. The recombinant 130 kDa (short) smMLCK phosphorylated S15 in MYL2 in vitro. Specific modification of S15 was verified using the direct detection of the phospho group on S15 with mass spectrometry. SmMLCK also specifically phosphorylated myosin regulatory light chain S15 in porcine ventricular myosin and chicken gizzard smooth muscle myosin (S20 in smooth muscle) but failed to phosphorylate the myosin regulatory light chain in rabbit skeletal myosin. Phosphorylation kinetics, measured using a novel fluorescence method eliminating the use of radioactive isotopes, indicates similar Michaelis-Menten V{sub max} and K{sub M} for regulatory light chain S15 phosphorylation rates in MYL2, porcine ventricular myosin, and chicken gizzard myosin. These data demonstrate that smMLCK is a specific and efficient kinase for the in vitro phosphorylation of MYL2, cardiac, and smooth muscle myosin. Whether smMLCK plays a role in cardiac muscle regulation or response to a disease causing stimulus is unclear but it should be considered a potentially

Reduction in saturated fat intake for cardiovascular disease.

PubMed

Hooper, Lee; Martin, Nicole; Abdelhamid, Asmaa; Davey Smith, George

2015-06-10

Reducing saturated fat reduces serum cholesterol, but effects on other intermediate outcomes may be less clear. Additionally it is unclear whether the energy from saturated fats that are lost in the diet are more helpfully replaced by polyunsaturated fats, monounsaturated fats, carbohydrate or protein. This review is part of a series split from and updating an overarching review. To assess the effect of reducing saturated fat intake and replacing it with carbohydrate (CHO), polyunsaturated (PUFA) or monounsaturated fat (MUFA) and/or protein on mortality and cardiovascular morbidity, using all available randomised clinical trials. We updated our searches of the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (Ovid) and EMBASE (Ovid) on 5 March 2014. We also checked references of included studies and reviews. Trials fulfilled the following criteria: 1) randomised with appropriate control group; 2) intention to reduce saturated fat intake OR intention to alter dietary fats and achieving a reduction in saturated fat; 3) not multifactorial; 4) adult humans with or without cardiovascular disease (but not acutely ill, pregnant or breastfeeding); 5) intervention at least 24 months; 6) mortality or cardiovascular morbidity data available. Two review authors working independently extracted participant numbers experiencing health outcomes in each arm, and we performed random-effects meta-analyses, meta-regression, subgrouping, sensitivity analyses and funnel plots. We include 15 randomised controlled trials (RCTs) (17 comparisons, ˜59,000 participants), which used a variety of interventions from providing all food to advice on how to reduce saturated fat. The included long-term trials suggested that reducing dietary saturated fat reduced the risk of cardiovascular events by 17% (risk ratio (RR) 0.83; 95% confidence interval (CI) 0.72 to 0.96, 13 comparisons, 53,300 participants of whom 8% had a cardiovascular event, I² 65%, GRADE moderate quality of

In-situ gas hydrate hydrate saturation estimated from various well logs at the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope

USGS Publications Warehouse

Lee, M.W.; Collett, T.S.

2011-01-01

In 2006, the U.S. Geological Survey (USGS) completed detailed analysis and interpretation of available 2-D and 3-D seismic data and proposed a viable method for identifying sub-permafrost gas hydrate prospects within the gas hydrate stability zone in the Milne Point area of northern Alaska. To validate the predictions of the USGS and to acquire critical reservoir data needed to develop a long-term production testing program, a well was drilled at the Mount Elbert prospect in February, 2007. Numerous well log data and cores were acquired to estimate in-situ gas hydrate saturations and reservoir properties.Gas hydrate saturations were estimated from various well logs such as nuclear magnetic resonance (NMR), P- and S-wave velocity, and electrical resistivity logs along with pore-water salinity. Gas hydrate saturations from the NMR log agree well with those estimated from P- and S-wave velocity data. Because of the low salinity of the connate water and the low formation temperature, the resistivity of connate water is comparable to that of shale. Therefore, the effect of clay should be accounted for to accurately estimate gas hydrate saturations from the resistivity data. Two highly gas hydrate-saturated intervals are identified - an upper ???43 ft zone with an average gas hydrate saturation of 54% and a lower ???53 ft zone with an average gas hydrate saturation of 50%; both zones reach a maximum of about 75% saturation. ?? 2009.

STUDIES ON THE AMOUNT OF LIGHT EMITTED BY MIXTURES OF CYPRIDINA LUCIFERIN AND LUCIFERASE

PubMed Central

Stevens, Kenneth P.

1927-01-01

1. A photometric method was devised for measuring the intensities of light emitted per cc. of hiciferin solution and calculating the amount of light emitted per gm. of dried Cypridina powder. A total of 128 runs was made and the data are incorporated in this report. 2. The maximum amount of light emitted from 1 gm. of powder under the experimental conditions was 0.655 lumens. Different samples of powder vary greatly in amount of light production. 3. When the concentration of substrate is doubled, nearly twice as much light is emitted, or an average ratio 2C/C of 1.86. Calculations of total light emissions per gm. of powder at different concentrations indicate that slightly more light is produced from the smaller concentrations. The maximum amount of light was produced by the solutions made with neutral sea water and averaged 0.445 lumens. The least light was obtained from solutions in distilled water saturated with hydrogen. The technique allows too rapid spontaneous oxidation prior to the saturation with hydrogen. The maximum amount of light from such experiments was only 0.077 lumens. Acid sea water solutions subsequently neutralized gave an average maximum of 0.386 lumens per gm. of powder per second. 4. When the concentration of enzyme is doubled, approximately the same amount of light is produced by both concentrations, although the stronger concentrations are slightly less effective than weaker ones. This undoubtedly is due to the colloidal nature of the enzyme and is a function of surface rather than of mass. In dilute solutions greater dispersion probably allows for greater adsorption to the surface of the enzyme. The average maximum amount of light produced in the series of enzyme experiments is of the magnitude 0.56 lumens per gm. of powder. PMID:19872366

White collar 2, a partner in blue-light signal transduction, controlling expression of light-regulated genes in Neurospora crassa.

PubMed Central

Linden, H; Macino, G

1997-01-01

A saturating genetic dissection of 'blind' mutants in Neurospora crassa has identified a total of two non-redundant loci (wc-1 and wc-2) each of which is required for blue-light perception/signal transduction. Previously, we demonstrated that WC1 is a putative zinc finger transcription factor able to bind specifically to a light-regulated promoter. Here, we present the cloning and characterization of the wc-2 gene. We demonstrate using mutation analysis and in vitro DNA-binding assays that WC2, the second partner of this light signal transduction system, encodes a functional zinc finger DNA-binding protein with putative PAS dimerization and transcription activation domains. This molecular genetic dissection of the second of two components of this light signal transduction system has enabled us to devise a model whereby WC1 and WC2 are proposed to interact via homologous PAS domains, bind to promoters of light-regulated genes and activate transcription. As such, this study provides the first insight into two co-operating partners in blue-light signal transduction in any organism and describes the molecular tools with which to dissect this enigmatic process. PMID:9009271

Ectomycorrhizal fungi reduce the light compensation point and promote carbon fixation of Pinus thunbergii seedlings to adapt to shade environments.

PubMed

Shi, Liang; Wang, Jie; Liu, Binhao; Nara, Kazuhide; Lian, Chunlan; Shen, Zhenguo; Xia, Yan; Chen, Yahua

2017-11-01

We examined the effects of three ectomycorrhizal (ECM) symbionts on the growth and photosynthesis capacity of Japanese black pine (Pinus thunbergii) seedlings and estimated physiological and photosynthetic parameters such as the light compensation point (LCP), biomass, and phosphorus (Pi) concentration of P. thunbergii seedlings. Through this investigation, we documented a new role of ectomycorrhizal (ECM) fungi: enhancement of the survival and competitiveness of P. thunbergii seedlings under low-light condition by reducing the LCP of seedlings. At a CO 2 concentration of 400 ppm, the LCP of seedlings with ECM inoculations was 40-70 μmol photons m -2  s -1 , significantly lower than that of non-mycorrhizal (NM) seedlings (200 μmol photons m -2  s -1 ). In addition, photosynthetic carbon fixation (Pn) increased with light intensity and CO 2 level, and the Pn of ECM seedlings was significantly higher than that of NM seedlings; Pisolithus sp. (Pt)- and Laccaria amethystea (La)-mycorrhizal seedlings had significantly lower Pn than Cenococcum geophilum (Cg)-mycorrhizal seedlings. However, La-mycorrhizal seedlings exhibited the highest fresh weight, relative water content (RWC), and the lowest LCP in the mycorrhizal group. Concomitantly, ECM seedlings showed significantly increased chlorophyll content of needles and higher Pi concentrations compared to NM seedlings. Overall, ECM symbionts promoted growth and photosynthesis while reducing the LCP of P. thunbergii seedlings. These findings indicate that ECM fungi can enhance the survival and competitiveness of host seedlings under low light.

Retinal vessel oxygen saturation in a healthy young Chinese population.

PubMed

Yang, Wei; Fu, Yue; Dong, Yanmin; Lin, Leilei; Huang, Xia; Li, Yujie; Lin, Xiaofeng; Gao, Qianying

2016-06-01

To measure retinal vessel oxygen saturation in a healthy young Chinese population and to determine the effects of multiple factors (gender, age, dioptre, vessel diameter and ocular perfusion pressure - OPP) on retinal oxygen saturation. A total of 126 healthy Chinese individuals aged from 19 to 30 were included in this study. A retinal oximeter (Oxymap T1) was used to measure retinal vessel oxygen saturation by retinal imaging at two different wavelengths. The mean retinal vessel oxygen saturation (Sat_O2 ) of arterioles, venules and arteriovenous (AV) difference overall and in four separate quadrants were measured. Intra-ocular pressure, blood pressure, finger pulse oximetry value, vessel diameter and dioptre were also measured. The correlations between OPP and dioptre, OPP and vessel diameter, and dioptre and vessel diameter were analysed. And the effects of multiple factors on the retinal oxygen saturation were analysed. The mean oxygen saturation was 93.2 ± 6.3% in the retinal arterioles, 60.4 ± 5.3% in venules and 32.9 ± 6.4% in AV difference. The temporal quadrants had lower measurements of arteriolar and venular oxygen saturation and AV difference compared with nasal quadrants (p < 0.001). The oxygen saturation of the arterioles, venules and AV difference were unaffected by any unique factor. Arteriolar and venular retinal oxygen saturation correlated negatively with the product of dioptre and OPP. Arteriolar retinal oxygen saturation correlated positively with the product of dioptre and vessel diameter. This study provided a normal reference of Sat_O2 in healthy young Chinese individuals. It was a reflection of the normal state of retinal oxygen metabolism affected by several factors. © 2016 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Brightness, hue, and saturation in photopic vision: a result of luminance and wavelength in the cellular phase-grating optical 3D chip of the inverted retina

NASA Astrophysics Data System (ADS)

Lauinger, Norbert

1994-10-01

In photopic vision, two physical variables (luminance and wavelength) are transformed into three psychological variables (brightness, hue, and saturation). Following on from 3D grating optical explanations of aperture effects (Stiles-Crawford effects SCE I and II), all three variables can be explained via a single 3D chip effect. The 3D grating optical calculations are carried out using the classical von Laue equation and demonstrated using the example of two experimentally confirmed observations in human vision: saturation effects for monochromatic test lights between 485 and 510 nm in the SCE II and the fact that many test lights reverse their hue shift in the SCE II when changing from moderate to high luminances compared with that on changing from low to medium luminances. At the same time, information is obtained on the transition from the trichromatic color system in the retina to the opponent color system.

Saturation-dependent solute dispersivity in porous media: Pore-scale processes

NASA Astrophysics Data System (ADS)

Raoof, A.; Hassanizadeh, S. M.

2013-04-01

It is known that in variably saturated porous media, dispersion coefficient depends on Darcy velocity and water saturation. In one-dimensional flow, it is commonly assumed that the dispersion coefficient is a linear function of velocity. The coefficient of proportionality, called the dispersivity, is considered to depend on saturation. However, there is not much known about its dependence on saturation. In this study, we investigate, using a pore network model, how the longitudinal dispersivity varies nonlinearly with saturation. We schematize the porous medium as a network of pore bodies and pore throats with finite volumes. The pore space is modeled using the multidirectional pore-network concept, which allows for a distribution of pore coordination numbers. This topological property together with the distribution of pore sizes are used to mimic the microstructure of real porous media. The dispersivity is calculated by solving the mass balance equations for solute concentration in all network elements and averaging the concentrations over a large number of pores. We have introduced a new formulation of solute transport within pore space, where we account for different compartments of residual water within drained pores. This formulation makes it possible to capture the effect of limited mixing due to partial filling of the pores under variably saturated conditions. We found that dispersivity increases with the decrease in saturation, it reaches a maximum value, and then decreases with further decrease in saturation. To show the capability of our formulation to properly capture the effect of saturation on solute dispersion, we applied it to model the results of a reported experimental study.

Saturated fats: a perspective from lactation and milk composition.

PubMed

German, J Bruce; Dillard, Cora J

2010-10-01

For recommendations of specific targets for the absolute amount of saturated fat intake, we need to know what dietary intake is most appropriate? Changing agricultural production and processing to lower the relative quantities of macronutrients requires years to accomplish. Changes can have unintended consequences on diets and the health of subsets of the population. Hence, what are the appropriate absolute amounts of saturated fat in our diets? Is the scientific evidence consistent with an optimal intake of zero? If not, is it also possible that a finite intake of saturated fats is beneficial to overall health, at least to a subset of the population? Conclusive evidence from prospective human trials is not available, hence other sources of information must be considered. One approach is to examine the evolution of lactation, and the composition of milks that developed through millennia of natural selective pressure and natural selection processes. Mammalian milks, including human milk, contain 50% of their total fatty acids as saturated fatty acids. The biochemical formation of a single double bond converting a saturated to a monounsaturated fatty acid is a pathway that exists in all eukaryotic organisms and is active within the mammary gland. In the face of selective pressure, mammary lipid synthesis in all mammals continues to release a significant content of saturated fatty acids into milk. Is it possible that evolution of the mammary gland reveals benefits to saturated fatty acids that current recommendations do not consider?

Red cell aspartate aminotransferase saturation with oral pyridoxine intake.

PubMed

Oshiro, Marilena; Nonoyama, Kimiyo; Oliveira, Raimundo Antônio Gomes; Barretto, Orlando Cesar de Oliveira

2005-03-02

The coenzyme of aspartate aminotransferase is pyridoxal phosphate, generated from fresh vegetables containing pyridoxine. Vitamin B6-responsive sideroblastic anemia, myelofibrosis and Peyronies syndrome respond to high pyridoxine doses. The objective was to investigate the oral pyridoxine oral dose that would lead to maximized pyridoxal phosphate saturation of red cell aspartate aminotransferase. Controlled trial, in Hematology Division of Instituto Adolfo Lutz. Red cell aspartate aminotransferase activity was assayed (before and after) in normal volunteers who were given oral pyridoxine for 15-18 days (30 mg, 100 mg and 200 mg daily). In vitro study of blood from seven normal volunteers was also performed, with before and after assaying of aspartate aminotransferase activity. The in vivo study showed increasing aspartate aminotransferase saturation with increasing pyridoxine doses. 83% saturation was reached with 30 mg daily, 88% with 100 mg, and 93% with 200 mg after 20 days of oral supplementation. The in vitro study did not reach 100% saturation. Neither in vivo nor in vitro study demonstrated thorough aspartate aminotransferase saturation with its coenzyme pyridoxal phosphate in red cells, from increasing pyridoxine supplementation. However, the 200-mg dose could be employed safely in vitamin B6-responsive sideroblastic anemia, myelofibrosis and Peyronies syndrome treatment. Although maximum saturation in circulating red cells is not achieved, erythroblasts and other nucleated and cytoplasmic organelles containing cells certainly will reach thorough saturation, which possibly explains the results obtained in these diseases.

Using Noble Gas Tracers to Estimate CO2 Saturation in the Field: Results from the 2014 CO2CRC Otway Repeat Residual Saturation Test

NASA Astrophysics Data System (ADS)

LaForce, T.; Ennis-King, J.; Boreham, C.; Serno, S.; Cook, P. J.; Freifeld, B. M.; Gilfillan, S.; Jarrett, A.; Johnson, G.; Myers, M.; Paterson, L.

2015-12-01

Residual trapping efficiency is a critical parameter in the design of secure subsurface CO2 storage. Residual saturation is also a key parameter in oil and gas production when a field is under consideration for enhanced oil recovery. Tracers are an important tool that can be used to estimate saturation in field tests. A series of measurements of CO2 saturation in an aquifer were undertaken as part of the Otway stage 2B extension field project in Dec. 2014. These tests were a repeat of similar tests in the same well in 2011 with improvements to the data collection and handling method. Two single-well tracer tests using noble gas tracers were conducted. In the first test krypton and xenon are injected into the water-saturated formation to establish dispersivity of the tracers in single-phase flow. Near-residual CO2 saturation is then established near the well. In the second test krypton and xenon are injected with CO2-saturated water to measure the final CO2 saturation. The recovery rate of the tracers is similar to predicted rates using recently published partitioning coefficients. Due to technical difficulties, there was mobile CO2 in the reservoir throughout the second tracer test in 2014. As a consequence, it is necessary to use a variation of the previous simulation procedure to interpret the second tracer test. One-dimensional, radial simulations are used to estimate average saturation of CO2 near the well. Estimates of final average CO2 saturation are computed using two relative permeability models, thermal and isothermal simulations, and three sets of coefficients for the partitioning of the tracers between phases. Four of the partitioning coefficients used were not previously available in the literature. The noble gas tracer field test and analysis of the 2011 and 2014 data both give an average CO2 saturation that is consistent with other field measurements. This study has demonstrated the repeatability of the methodology for noble gas tracer tests in the

3. Light tower, view northwest, south side Ram Island ...

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

3. Light tower, view northwest, south side - Ram Island Light Station, Ram Island, south of Ocean Point & just north of Fisherman Island, marking south side of Fisherman Island Passage, Ocean Point, Lincoln County, ME

Low-intensity blue-enriched white light (750 lux) and standard bright light (10,000 lux) are equally effective in treating SAD. A randomized controlled study.

PubMed

Meesters, Ybe; Dekker, Vera; Schlangen, Luc J M; Bos, Elske H; Ruiter, Martine J

2011-01-28

Photoreceptor cells containing melanopsin play a role in the phase-shifting effects of short-wavelength light. In a previous study, we compared the standard light treatment (SLT) of SAD with treatment using short-wavelength blue-enriched white light (BLT). Both treatments used the same illuminance (10,000 lux) and were equally highly effective. It is still possible, however, that neither the newly-discovered photoreceptor cells, nor the biological clock play a major role in the therapeutic effects of light on SAD. Alternatively, these effects may at least be partly mediated by these receptor cells, which may have become saturated as a result of the high illuminances used in the therapy. This randomized controlled study compares the effects of low-intensity BLT to those of high-intensity SLT. In a 22-day design, 22 patients suffering from a major depression with a seasonal pattern (SAD) were given light treatment (10,000 lux) for two weeks on workdays. Subjects were randomly assigned to either of the two conditions, with gender and age evenly distributed over the groups. Light treatment either consisted of 30 minutes SLT (5000 °K) with the EnergyLight® (Philips, Consumer Lifestyle) with a vertical illuminance of 10,000 lux at eye position or BLT (17,000 °K) with a vertical illuminance of 750 lux using a prototype of the EnergyLight® which emitted a higher proportion of short-wavelengths. All participants completed questionnaires concerning mood, activation and sleep quality on a daily basis. Mood and energy levels were also assessed on a weekly basis by means of the SIGH-SAD and other assessment tools. On day 22, SIGH-SAD ratings were significantly lower than on day 1 (SLT 65.2% and BLT 76.4%). On the basis of all assessments no statistically significant differences were found between the two conditions. With sample size being small, conclusions can only be preliminary. Both treatment conditions were found to be highly effective. The therapeutic effects of low

Growth and Development Temperature Influences Level of Tolerance to High Light Stress 1

PubMed Central

Steffen, Kenneth L.; Palta, Jiwan P.

1989-01-01

The influence of growth and development temperature on the relative tolerance of photosynthetic tissue to high light stress at chilling temperatures was investigated. Two tuber-bearing potato species, Solanum tuberosum L. cv Red Pontiac and Solanum commersonii were grown for 4 weeks, at either 12 or 24°C with 12 hours of about 375 micromoles per second per square meter of photosynthetically active radiation. Paired leaf discs were cut from directly across the midvein of leaflets of comparable developmental stage and light environment from each species at each growth temperature treatment. One disc of each pair was exposed to 1°C and about 1000 micromoles per second per square meter photosynthetically active radiation for 4 hours, and the other disc was held at 1°C in total darkness for the same duration. Photosynthetic tissue of S. tuberosum, developed at 12°C, was much more tolerant to high light and low temperature stress than tissue developed under 24°C conditions. Following the high light treatment, 24°C-grown S. tuberosum tissue demonstrated light-limited and light-saturated rates that were approximately 50% of their paired dark controls. In contrast, the 12°C-grown tissue from S. tuberosum that was subjected to the light stress showed only a 18 and 6% reduction in light-limited and light-saturated rates of photosynthetic oxygen evolution, respectively. Tissue from 24°C-grown S. commersonii was much less sensitive to the light stress than was tissue from S. tuberosum grown under the same conditions. The results presented here demonstrate that: (a) acclimation of S. tuberosum to lower temperature growth conditions with a constant light environment, results in the increased capacity of photosynthetic tissue to tolerate high light stress at chilling temperature and (b) following growth and development at relatively high temperatures S. commersonii, a frost- and heat-tolerant wild species, has a much greater tolerance to the high light stress at chilling

Study on Two-Phase Flow in Heterogeneous Porous Media by Light Transmission Method

NASA Astrophysics Data System (ADS)

Qiao, W.

2015-12-01

The non-aqueous phase liquid (NAPL) released to the subsurface can form residual ganglia and globules occupying pores and also accumulate and form pools, in which multiphase system forms. Determining transient fluid saturations in a multiphase system is essential to understand the flow characteristics of systems and to perform effective remediation strategies. As a non-destructive and non-invasive laboratory technique utilized for the measurement of liquid saturation in porous media, light transmission is of the lowest cost and safe. Utilization of Coupled Charge Device camera in light transmission systems provides a nearly instantaneous high-density array of spatial measurements over a very large dynamic range. The migration of NAPL and air spariging technique applied to remove NAPL in aquifer systems are typically two-phase flow problem. Because of the natural aquifer normally being heterogeneous, two 2-D sandboxes (Length55cm×width1.3cm×hight45cm) are set up to study the migration of gas and DNAPL in heterogeneous porous media based on light transmission method and its application in two-phase flow. Model D for water/gas system developed by Niemet and Selker (2001) and Model NW-A for water/NAPL system developed by Zhang et al. (2014) are applied for the calculation of fluid saturation in the two experiments, respectively. The gas injection experiments show that the gas moves upward in the irregular channels, piling up beneath the low permeability lenses and starting lateral movement. Bypassing the lenses, the gas moves upward and forms continuous distribution in the top of the sandbox. The faster of gas injects, the wider of gas migration will be. The DNAPL infiltration experiment shows that TCE mainly moves downward as the influence of gravity, stopping vertical infiltration when reaching the low permeability lenses because of its failure to overcome the capillary pressure. Then, TCE accumulates on the surface and starts transverse movement. Bypassing the

Low-Power Photoplethysmogram Acquisition Integrated Circuit with Robust Light Interference Compensation.

PubMed

Kim, Jongpal; Kim, Jihoon; Ko, Hyoungho

2015-12-31

To overcome light interference, including a large DC offset and ambient light variation, a robust photoplethysmogram (PPG) readout chip is fabricated using a 0.13-μm complementary metal-oxide-semiconductor (CMOS) process. Against the large DC offset, a saturation detection and current feedback circuit is proposed to compensate for an offset current of up to 30 μA. For robustness against optical path variation, an automatic emitted light compensation method is adopted. To prevent ambient light interference, an alternating sampling and charge redistribution technique is also proposed. In the proposed technique, no additional power is consumed, and only three differential switches and one capacitor are required. The PPG readout channel consumes 26.4 μW and has an input referred current noise of 260 pArms.

Transition to Turbulent Dynamo Saturation

NASA Astrophysics Data System (ADS)

Seshasayanan, Kannabiran; Gallet, Basile; Alexakis, Alexandros

2017-11-01

While the saturated magnetic energy is independent of viscosity in dynamo experiments, it remains viscosity dependent in state-of-the-art 3D direct numerical simulations (DNS). Extrapolating such viscous scaling laws to realistic parameter values leads to an underestimation of the magnetic energy by several orders of magnitude. The origin of this discrepancy is that fully 3D DNS cannot reach low enough values of the magnetic Prandtl number Pm. To bypass this limitation and investigate dynamo saturation at very low Pm, we focus on the vicinity of the dynamo threshold in a rapidly rotating flow: the velocity field then depends on two spatial coordinates only, while the magnetic field consists of a single Fourier mode in the third direction. We perform numerical simulations of the resulting set of reduced equations for Pm down to 2 ×10-5. This parameter regime is currently out of reach to fully 3D DNS. We show that the magnetic energy transitions from a high-Pm viscous scaling regime to a low-Pm turbulent scaling regime, the latter being independent of viscosity. The transition to the turbulent saturation regime occurs at a low value of the magnetic Prandtl number, Pm ≃10-3 , which explains why it has been overlooked by numerical studies so far.

Transition to Turbulent Dynamo Saturation.

PubMed

Seshasayanan, Kannabiran; Gallet, Basile; Alexakis, Alexandros

2017-11-17

While the saturated magnetic energy is independent of viscosity in dynamo experiments, it remains viscosity dependent in state-of-the-art 3D direct numerical simulations (DNS). Extrapolating such viscous scaling laws to realistic parameter values leads to an underestimation of the magnetic energy by several orders of magnitude. The origin of this discrepancy is that fully 3D DNS cannot reach low enough values of the magnetic Prandtl number Pm. To bypass this limitation and investigate dynamo saturation at very low Pm, we focus on the vicinity of the dynamo threshold in a rapidly rotating flow: the velocity field then depends on two spatial coordinates only, while the magnetic field consists of a single Fourier mode in the third direction. We perform numerical simulations of the resulting set of reduced equations for Pm down to 2×10^{-5}. This parameter regime is currently out of reach to fully 3D DNS. We show that the magnetic energy transitions from a high-Pm viscous scaling regime to a low-Pm turbulent scaling regime, the latter being independent of viscosity. The transition to the turbulent saturation regime occurs at a low value of the magnetic Prandtl number, Pm≃10^{-3}, which explains why it has been overlooked by numerical studies so far.

Advantages of estimating parameters of photosynthesis model by fitting A-Ci curves at multiple subsaturating light intensities

NASA Astrophysics Data System (ADS)

Fu, W.; Gu, L.; Hoffman, F. M.

2013-12-01

The photosynthesis model of Farquhar, von Caemmerer & Berry (1980) is an important tool for predicting the response of plants to climate change. So far, the critical parameters required by the model have been obtained from the leaf-level measurements of gas exchange, namely the net assimilation of CO2 against intercellular CO2 concentration (A-Ci) curves, made at saturating light conditions. With such measurements, most points are likely in the Rubisco-limited state for which the model is structurally overparameterized (the model is also overparameterized in the TPU-limited state). In order to reliably estimate photosynthetic parameters, there must be sufficient number of points in the RuBP regeneration-limited state, which has no structural over-parameterization. To improve the accuracy of A-Ci data analysis, we investigate the potential of using multiple A-Ci curves at subsaturating light intensities to generate some important parameter estimates more accurately. Using subsaturating light intensities allow more RuBp regeneration-limited points to be obtained. In this study, simulated examples are used to demonstrate how this method can eliminate the errors of conventional A-Ci curve fitting methods. Some fitted parameters like the photocompensation point and day respiration impose a significant limitation on modeling leaf CO2 exchange. The multiple A-Ci curves fitting can also improve over the so-called Laisk (1977) method, which was shown by some recent publication to produce incorrect estimates of photocompensation point and day respiration. We also test the approach with actual measurements, along with suggested measurement conditions to constrain measured A-Ci points to maximize the occurrence of RuBP regeneration-limited photosynthesis. Finally, we use our measured gas exchange datasets to quantify the magnitude of resistance of chloroplast and cell wall-plasmalemma and explore the effect of variable mesophyll conductance. The variable mesophyll conductance

Volatility and vapor saturation of pine resins

Treesearch

Richard H. Smith

1963-01-01

Volatility and vapor saturation were obtained for closed-faced collected resin of 10 pine species and 4 hybrids in California. Volatility ranged from 2 to 32 percent at 25°C., and from 14 to 36 percent at 100°C. Hybrids were usually less volatile than either parent. Vapor saturation ranged widely between species, from 2 to 20 mg. per 150 cc., but only...

Oxygen saturation in optic nerve head structures by hyperspectral image analysis.

PubMed

Beach, James; Ning, Jinfeng; Khoobehi, Bahram

2007-02-01

A method is presented for the calculation and visualization of percent blood oxygen saturation from specific tissue structures in hyperspectral images of the optic nerve head (ONH). Trans-pupillary images of the primate optic nerve head and overlying retinal blood vessels were obtained with a hyperspectral imaging (HSI) system attached to a fundus camera. Images were recorded during normal blood flow and after partially interrupting flow to the ONH and retinal circulation by elevation of the intraocular pressure (IOP) from 10 mmHg to 55 mmHg in steps. Percent oxygen saturation was calculated from groups of pixels associated with separate tissue structures, using a linear least-squares curve fit of the recorded hemoglobin spectrum to reference spectra obtained from fully oxygenated and deoxygenated red cell suspensions. Color maps of saturation were obtained from a new algorithm that enables comparison of oxygen saturation from large vessels and tissue areas in hyperspectral images. Percent saturation in retinal vessels and from the average over ONH structures (IOP = 10 mmHg) was (mean +/- SE): artery 81.8 +/- 0.4%, vein 42.6 +/- 0.9%, average ONH 68.3 +/- 0.4%. Raising IOP from 10 mmHg to 55 mmHg for 5 min caused blood oxygen saturation to decrease (mean +/- SE): artery 46.1 +/- 6.2%, vein 36.1 +/- 1.6%, average ONH 41.9 +/- 1.6%. The temporal cup showed the highest saturation at low and high IOP (77.3 +/- 1.0% and 60.1 +/- 4.0%) and the least reduction in saturation at high IOP (22.3%) compared with that of the average ONH (38.6%). A linear relationship was found between saturation indices obtained from the algorithm and percent saturation values obtained by spectral curve fits to calibrated red cell samples. Percent oxygen saturation was determined from hyperspectral images of the ONH tissue and retinal vessels overlying the ONH at normal and elevated IOP. Pressure elevation was shown to reduce blood oxygen saturation in vessels and ONH structures, with the

A demonstration experiment for studying the properties of saturated vapor

NASA Astrophysics Data System (ADS)

Grebenev, Igor V.; Lebedeva, Olga V.; Polushkina, Svetlana V.

2017-11-01

The paper proposes an important demonstration experiment that can be used at secondary schools in physics. The described experiment helps students learn the main concepts of the topic ‘saturated vapor’, namely, evaporation, condensation, dynamic equilibrium, saturation vapor, partial pressure, and the dependence of saturated vapor pressure on temperature.

Light Microscopy Microscope Experiment

NASA Image and Video Library

2016-02-04

Ground testing for the first confocal Light Microscopy Microscope (LMM) Experiment. Procter and Gamble is working with NASA Glenn scientists to prepare for a study that examines product stabilizers in a microgravity environment. The particles in the tube glow orange because they have been fluorescently tagged with a dye that reacts to green laser lights to allow construction of a 3D image point by point. The experiment, which will be sent to the ISS later this year, will help P&G develop improved product stabilizers to extend shelf life and develop more environmentally friendly packaging.

Saturable inductor and transformer structures for magnetic pulse compression

DOEpatents

Birx, Daniel L.; Reginato, Louis L.

1990-01-01

Saturable inductor and transformer for magnetic compression of an electronic pulse, using a continuous electrical conductor looped several times around a tightly packed core of saturable inductor material.

Apparatus and method for creating a photonic densely-accumulated ray-point

NASA Technical Reports Server (NTRS)

Park, Yeonjoon (Inventor); Choi, Sang H. (Inventor); King, Glen C. (Inventor); Elliott, James R. (Inventor)

2012-01-01

An optical apparatus includes an optical diffraction device configured for diffracting a predetermined wavelength of incident light onto adjacent optical focal points, and a photon detector for detecting a spectral characteristic of the predetermined wavelength. One of the optical focal points is a constructive interference point and the other optical focal point is a destructive interference point. The diffraction device, which may be a micro-zone plate (MZP) of micro-ring gratings or an optical lens, generates a constructive ray point using phase-contrasting of the destructive interference point. The ray point is located between adjacent optical focal points. A method of generating a densely-accumulated ray point includes directing incident light onto the optical diffraction device, diffracting the selected wavelength onto the constructive interference focal point and the destructive interference focal point, and generating the densely-accumulated ray point in a narrow region.

Selective imaging of saturated and unsaturated lipids by wide-field CARS-microscopy.

PubMed

Heinrich, Christoph; Hofer, Alexander; Ritsch, Andreas; Ciardi, Christian; Bernet, Stefan; Ritsch-Marte, Monika

2008-02-18

Wide-field Coherent Anti-Stokes Raman Scattering (CARS) microscopy is employed to identify saturated and unsaturated fatty acids in micro-emulsions and cells, using the ratio between the strong -C-H CARS signal at 2850 cm(-1) and the weak signal of the =C-H vibration around 3015 cm(-1) for distinction. Quantitative CARS imaging at the =C-H resonance is challenging, since it yields only a low CARS signal, and small differences on the order of 5% in the concentration of polyunsaturated fatty lipids have to be detected. For this purpose we draw advantage of the high signal-to-noise ratio of wide-field CARS microscopy that is achieved by an excitation geometry involving a "sheet-of-light"-type illumination.

46 CFR 7.120 - Mexican/United States border to Point Fermin, CA.

Code of Federal Regulations, 2014 CFR

2014-10-01

... BOUNDARY LINES Pacific Coast § 7.120 Mexican/United States border to Point Fermin, CA. (a) A line drawn... 46 Shipping 1 2014-10-01 2014-10-01 false Mexican/United States border to Point Fermin, CA. 7.120... “5”); thence to Point Loma Light. (b) A line drawn from Mission Bay South Jetty Light “2” to Mission...

46 CFR 7.120 - Mexican/United States border to Point Fermin, CA.

Code of Federal Regulations, 2012 CFR

2012-10-01

... BOUNDARY LINES Pacific Coast § 7.120 Mexican/United States border to Point Fermin, CA. (a) A line drawn... 46 Shipping 1 2012-10-01 2012-10-01 false Mexican/United States border to Point Fermin, CA. 7.120... “5”); thence to Point Loma Light. (b) A line drawn from Mission Bay South Jetty Light “2” to Mission...

46 CFR 7.120 - Mexican/United States border to Point Fermin, CA.

Code of Federal Regulations, 2010 CFR

2010-10-01

... BOUNDARY LINES Pacific Coast § 7.120 Mexican/United States border to Point Fermin, CA. (a) A line drawn... 46 Shipping 1 2010-10-01 2010-10-01 false Mexican/United States border to Point Fermin, CA. 7.120... “5”); thence to Point Loma Light. (b) A line drawn from Mission Bay South Jetty Light “2” to Mission...

46 CFR 7.120 - Mexican/United States border to Point Fermin, CA.

Code of Federal Regulations, 2013 CFR

2013-10-01

... BOUNDARY LINES Pacific Coast § 7.120 Mexican/United States border to Point Fermin, CA. (a) A line drawn... 46 Shipping 1 2013-10-01 2013-10-01 false Mexican/United States border to Point Fermin, CA. 7.120... “5”); thence to Point Loma Light. (b) A line drawn from Mission Bay South Jetty Light “2” to Mission...

46 CFR 7.120 - Mexican/United States border to Point Fermin, CA.

Code of Federal Regulations, 2011 CFR

2011-10-01

... BOUNDARY LINES Pacific Coast § 7.120 Mexican/United States border to Point Fermin, CA. (a) A line drawn... 46 Shipping 1 2011-10-01 2011-10-01 false Mexican/United States border to Point Fermin, CA. 7.120... “5”); thence to Point Loma Light. (b) A line drawn from Mission Bay South Jetty Light “2” to Mission...

Quantum hacking on a practical continuous-variable quantum cryptosystem by inserting an external light

NASA Astrophysics Data System (ADS)

Qin, Hao; Kumar, Rupesh; Alleaume, Romain

2015-10-01

We report here a new side channel attack on a practical continuous-variable (CV) quantum key distribution (QKD) system. Inspired by blinding attack in discrete-variable QKD, we formalize an attack strategy by inserting an external light into a CV QKD system implemented Gaussian-modulated coherent state protocol and show that our attack can compromise its practical security. In this attack, we concern imperfections of a balanced homodyne detector used in CV QKD. According to our analysis, if one inserts an external light into Bob's signal port, due to the imperfect subtraction from the homodyne detector, the leakage of the external light contributes a displacement on the homodyne signal which causes detector electronics saturation. In consequence, Bob's quadrature measurement is not linear with the quadrature sent by Alice. By considering such vulnerability, a potential Eve can launch a full intercept-resend attack meanwhile she inserts an external light into Bob's signal port. By selecting proper properties of the external light, Eve actively controls the induced displacement value from the inserted light which results saturation of homodyne detection. In consequence, Eve can bias the excess noise due to the intercept-resend attack and the external light, such that Alice and Bob believe their excess noise estimation is below the null key threshold and they can still share a secret key. Our attack shows that the detector loopholes also exist in CV QKD, and it seems influence all the CV QKD systems using homodyne detection, since all the practical detectors have finite detection range.

Monoterpene and sesquiterpene emissions from Quercus coccifera exhibit interacting responses to light and temperature

NASA Astrophysics Data System (ADS)

Staudt, M.; Lhoutellier, L.

2011-09-01

Light and temperature are known to be the most important environmental factors controlling biogenic volatile organic compound (BVOC) emissions from plants, but little is known about their interdependencies especially for BVOCs other than isoprene. We studied light responses at different temperatures and temperature responses at different light levels of foliar BVOC emissions, photosynthesis and chlorophyll fluorescence on Quercus coccifera, an evergreen oak widespread in Mediterranean shrublands. More than 50 BVOCs were detected in the emissions from Q. coccifera leaves most of them being isoprenoids plus a few green leaf volatiles (GLVs). Under standard conditions non-oxygenated monoterpenes (MT-hc) accounted for about 90% of the total BVOC release (mean ± SD: 738 ± 378 ng m-2 projected leaf area s-1 or 13.1 ± 6.9 μg g-1 leaf dry weight h-1) and oxygenated monoterpenes (MT-ox) and sesquiterpenes (SQTs) accounted for the rest in about equal proportions. Except GLVs, emissions of all BVOCs responded positively to light and temperature. The light responses of MT and SQT emissions resembled that of CO2-assimilation and were little influenced by the assay temperature: at high assay temperature, MT-hc emissions saturated at lower light levels than at standard assay temperature and tended even to decrease in the highest light range. The emission responses to temperature showed mostly Arrhenius-type response curves, whose shapes in the high temperature range were clearly affected by the assay light level and were markedly different between isoprenoid classes: at non-saturating light, all isoprenoids showed a similar temperature optimum (~43 °C), but, at higher temperatures, MT-hc emissions decreased faster than MT-ox and SQT emissions. At saturating light, MT-hc emissions peaked around 37 °C and rapidly dropped at higher temperatures, whereas MT-ox and SQT emissions strongly increased between 40 and 50 °C accompanied by a burst of GLVs. In all experiments

Monoterpene and sesquiterpene emissions from Quercus coccifera exhibit interacting responses to light and temperature

NASA Astrophysics Data System (ADS)

Staudt, M.; Lhoutellier, L.

2011-06-01

Light and temperature are known to be the most important environmental factors controlling biogenic volatile organic compound (BVOC) emissions from plants, but little is known about their interdependencies especially for BVOCs other than isoprene. We studied light responses at different temperatures and temperature responses at different light levels of foliar BVOC emissions, photosynthesis and chlorophyll fluorescence on Quercus coccifera, an evergreen oak widespread in Mediterranean shrublands. More than 50 BVOCs were detected in the emissions from Q. coccifera leaves most of them being isoprenoids plus a few green leaf volatiles (GLVs). Under standard conditions non-oxygenated monoterpenes (MT-hc) accounted for about 90 % of the total BVOC release (mean ± SD: 738 ± 378 ng m-2 projected leaf area s-1 or 13.1 ± 6.9 μg g-1 leaf dry weight h-1) and oxygenated monoterpenes (MT-ox) and sesquiterpenes (SQTs) accounted for the rest in about equal proportions. Except GLVs, emissions of all BVOCs responded positively to light and temperature. The light responses of MT and SQT emissions resembled that of CO2-assimilation and were little influenced by the assay temperature: at high assay temperature, MT-hc emissions saturated at lower light levels than at standard assay temperature and tended even to decrease in the highest light range. The emission responses to temperature showed mostly Arrhenius-type response curves, whose shapes in the high temperature range were clearly affected by the assay light level and were markedly different between isoprenoid classes: at non-saturating light, all isoprenoids showed a similar temperature optimum (~43 °C), but, at higher temperatures, MT-hc emissions decreased faster than MT-ox and SQT emissions. At saturating light, MT-hc emissions peaked already around 37 °C and rapidly dropped at higher temperatures, whereas MT-ox and SQT emissions strongly increased between 40 and 50 °C accompanied by a burst of GLVs. In all experiments

Statistical prescission point model of fission fragment angular distributions

NASA Astrophysics Data System (ADS)

John, Bency; Kataria, S. K.

1998-03-01

In light of recent developments in fission studies such as slow saddle to scission motion and spin equilibration near the scission point, the theory of fission fragment angular distribution is examined and a new statistical prescission point model is developed. The conditional equilibrium of the collective angular bearing modes at the prescission point, which is guided mainly by their relaxation times and population probabilities, is taken into account in the present model. The present model gives a consistent description of the fragment angular and spin distributions for a wide variety of heavy and light ion induced fission reactions.

Correlation of fetal oxygen saturation to fetal heart rate patterns. Evaluation of fetal pulse oximetry with two different oxisensors.

PubMed

Luttkus, A K; Friedmann, W; Homm-Luttkus, C; Dudenhausen, J W

1998-03-01

The purpose of this study was the correlation of fetal oxygen saturation values to various fetal heart rate patterns, as well as to oxygen saturation values obtained by fetal blood analysis. These objectives need to be evaluated from the perspective that two generations of fetal oxisensors have been used. Two different oxisensor systems (FS10: 660+890 nm and FS14: 735+890 nm) and a blinded pulse oximeter (type N400, Nellcor Puritan Bennett) were utilized to monitor 112 fetuses. All data, including oxygen saturation, fetal heart rate patterns, signal and contact quality were stored on a personal computer and evaluated after delivery. The following median fetal oxygen saturation values were obtained: during reassuring fetal heart rate sequences 54% with the oxisensor FS10 and 48% with the newer FS14 oxisensor, during intervals of variable decelerations 43% with the FS10 oxisensor and 40% with the FS14 oxisensor. These differences between values obtained during normal and abnormal fetal heart rate patterns are significant. Due to non-reassuring fetal heart rate patterns 81 fetal blood analyses were performed. The values of pulse oximetry were 9% higher (6% for the FS14) than those of spectrophotometry. Correlation of both methods was r=0.66 (0.74 for the FS14). In combination with fetal heart rate monitoring, fetal pulse oximetry promises a better differentiation between low and high risk heart rate patterns. Oxygen saturation values from intermittent fetal blood sampling reassure the clinician concerning the accuracy of this new method of intrapartum fetal surveillance and underline the increased quality of the new generation of oxisensor using light of a wavelength of 735 and 890 nm.

Saturation of the Hosing Instability in Quasilinear Plasma Accelerators

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

Lehe, R.; Schroeder, C. B.; Vay, J. -L.

The beam hosing instability is analyzed theoretically for a witness beam in the quasilinear regime of plasma accelerators. In this regime, the hosing instability saturates, even for a monoenergetic bunch, at a level much less than standard scalings predict. Analytic expressions are derived for the saturation distance and amplitude and are in agreement with numerical results. Saturation is due to the natural head-to-tail variations in the focusing force, including the self-consistent transverse beam loading.

Saturation of the Hosing Instability in Quasilinear Plasma Accelerators

DOE PAGES

Lehe, R.; Schroeder, C. B.; Vay, J. -L.; ...

2017-12-13

The beam hosing instability is analyzed theoretically for a witness beam in the quasilinear regime of plasma accelerators. In this regime, the hosing instability saturates, even for a monoenergetic bunch, at a level much less than standard scalings predict. Analytic expressions are derived for the saturation distance and amplitude and are in agreement with numerical results. Saturation is due to the natural head-to-tail variations in the focusing force, including the self-consistent transverse beam loading.

Velocity of water flow along saturated loess slopes under erosion effects

NASA Astrophysics Data System (ADS)

Huang, Yuhan; Chen, Xiaoyan; Li, Fahu; Zhang, Jing; Lei, Tingwu; Li, Juan; Chen, Ping; Wang, Xuefeng

2018-06-01

Rainfall or snow-melted water recharge easily saturates loose top soils with a less permeable underlayer, such as cultivated soil slope and partially thawed top soil layer, and thus, may influence the velocity of water flow. This study suggested a methodology and device system to supply water from the bottom soil layer at the different locations of slopes. Water seeps into and saturates the soil, when the water level is controlled at the same height of the soil surface. The structures and functions of the device, the components, and the operational principles are described in detail. A series of laboratory experiments were conducted under slope gradients of 5°, 10°, 15°, and 20° and flow rates of 2, 4, and 8 L min-1 to measure the water flow velocities over eroding and non-eroded loess soil slopes, under saturated conditions by using electrolyte tracing. Results showed that flow velocities on saturated slopes were 17% to 88% greater than those on non-saturated slopes. Flow velocity increased rapidly under high flow rates and slope gradients. Saturation conditions were suitable in maintaining smooth rill geomorphology and causing fast water flow. The saturated soil slope had a lubricant effect on the soil surface to reduce the frictional force, resulting in high flow velocity. The flow velocities of eroding rills under different slope gradients and flow rates were approximately 14% to 33% lower than those of non-eroded rills on saturated loess slopes. Compared with that on a saturated loess slope, the eroding rill on a non-saturated loess slope can produce headcuts to reduce the flow velocity. This study helps understand the hydrodynamics of soil erosion and sediment transportation of saturated soil slopes.

Effect of sensor location on regional cerebral oxygen saturation measured by INVOS 5100 in on-pump cardiac surgery.

PubMed

Cho, Ah-Reum; Kwon, Jae-Young; Kim, Choongrak; Hong, Jung-Min; Kang, Christine

2017-04-01

Near-infrared spectroscopy sensors often cannot be attached at the commercially recommended locations because combined use of neurological monitoring systems is common during on-pump cardiac surgery. The primary purpose of this study was to compare the incidence of regional cerebral oxygen desaturation and regional cerebral oxygen saturation values detected using near-infrared spectroscopy between the upper and lower forehead during on-pump cardiac surgery. A prospective observational study was conducted with 25 adult patients scheduled for elective on-pump cardiac surgery. Regional cerebral oxygen saturations at the left upper and lower forehead and other clinical measurements were monitored intraoperatively. McNemar's test was used to analyze differences in the incidence of cerebral regional oxygen desaturation between the left upper and lower forehead. Two-way repeated measures ANOVA with post hoc Bonferroni correction was used to compare the regional cerebral oxygen saturation at each time point. There was a significantly higher incidence of regional cerebral oxygen desaturation at the upper than lower forehead only at 1 h after initiation of aortic cross-clamping. There were significant differences between the left upper and lower regional cerebral oxygen saturation values throughout the observation period. Regional cerebral oxygen saturation was significantly lower at the upper than lower forehead during on-pump cardiac surgery. However, disagreements in detection of cerebral regional oxygen desaturation were only significant at 1 h after initiation of aortic cross-clamping. WHO-ICTRP, Clinical Research Information Service (CRiS). ID: KCT0000971. URL: https://cris.nih.go.kr/cris/search/search_result_st01_en.jsp?seq=3678&type=my .

Age-congruency and contact effects in body expression recognition from point-light displays (PLD)

PubMed Central

Hermens, Frouke; Willmott, Alexander P.

2016-01-01

Recognition of older people’s body expressions is a crucial social skill. We here investigate how age, not just of the observer, but also of the observed individual, affects this skill. Age may influence the ability to recognize other people’s body expressions by changes in one’s own ability to perform certain action over the life-span (i.e., an own-age bias may occur, with best recognition for one’s own age). Whole body point light displays of children, young adults and older adults (>70 years) expressing six different emotions were presented to observers of the same three age-groups. Across two variations of the paradigm, no evidence for the predicted own-age bias (a cross-over interaction between one’s own age and the observed person’s age) was found. Instead, experience effects were found with children better recognizing older actors’ expressions of ‘active emotions,’ such as anger and happiness with greater exposure in daily life. Together, the findings suggest that age-related changes in one own’s mobility only influences body expression categorization in young children who interact frequently with older adults. PMID:27994986

Effect of an oxygen pressure injection (OPI) device on the oxygen saturation of patients during dermatological methyl aminolevulinate photodynamic therapy.

PubMed

Blake, E; Allen, J; Thorn, C; Shore, A; Curnow, A

2013-05-01

Methyl aminolevulinate photodynamic therapy (MAL-PDT) (a topical treatment used for a number of precancerous skin conditions) utilizes the combined interaction of a photosensitizer (protoporphyrin IX (PpIX)), light of the appropriate wavelength, and molecular oxygen to produce singlet oxygen and other reactive oxygen species which induce cell death. During treatment, localized oxygen depletion occurs and is thought to contribute to decreased efficacy. The aim of this study was to investigate whether an oxygen pressure injection (OPI) device had an effect on localized oxygen saturation levels and/or PpIX fluorescence of skin lesions during MAL-PDT. This study employed an OPI device to apply oxygen under pressure to the skin lesions of patients undergoing standard MAL-PDT. Optical reflectance spectrometry and fluorescence imaging were used to noninvasively monitor the localized oxygen saturation and PpIX fluorescence of the treatment area, respectively. No significant changes in oxygen saturation were observed when these data were combined for the group with OPI and compared to the group that received standard MAL-PDT without OPI. Additionally, no significant difference in PpIX photobleaching or clinical outcome at 3 months between the groups of patients was observed, although the group that received standard MAL-PDT demonstrated a significant increase (p<0.05) in PpIX fluorescence initially and both groups produced a significant decrease (p<0.05) after light irradiation. In conclusion, with this sample size, this OPI device was not found to be an effective method with which to improve tissue oxygenation during MAL-PDT. Further investigation is therefore required to find a more effective method of MAL-PDT enhancement.

Molybdenite saturation in silicic magmas: Occurrence and petrological implications

USGS Publications Warehouse

Audetat, A.; Dolejs, D.; Lowenstern, J. B.

2011-01-01

We identified molybdenite (MoS2) as an accessory magmatic phase in 13 out of 27 felsic magma systems examined worldwide. The molybdenite occurs as small (<20 ??m) triangular or hexagonal platelets included in quartz phenocrysts. Laser-ablation inductively coupled plasma mass spectrometry analyses of melt inclusions in molybdenite-saturated samples reveal 1-13 ppm Mo in the melt and geochemical signatures that imply a strong link to continental rift basalt-rhyolite associations. In contrast, arc-associated rhyolites are rarely molybdenite-saturated, despite similar Mo concentrations. This systematic dependence on tectonic setting seems to reflect the higher oxidation state of arc magmas compared with within-plate magmas. A thermodynamic model devised to investigate the effects of T, f O2 and f S2 on molybdenite solubility reliably predicts measured Mo concentrations in molybdenite-saturated samples if the magmas are assumed to have been saturated also in pyrrhotite. Whereas pyrrhotite microphenocrysts have been observed in some of these samples, they have not been observed from other molybdenite-bearing magmas. Based on the strong influence of f S2 on molybdenite solubility we calculate that also these latter magmas must have been at (or very close to) pyrrhotite saturation. In this case the Mo concentration of molybdenite-saturated melts can be used to constrain both magmatic f O2 and f S2 if temperature is known independently (e.g. by zircon saturation thermometry). Our model thus permits evaluation of magmatic f S2, which is an important variable but is difficult to estimate otherwise, particularly in slowly cooled rocks. ?? The Author 2011. Published by Oxford University Press. All rights reserved.

Low threshold L-band mode-locked ultrafast fiber laser assisted by microfiber-based carbon nanotube saturable absorber

NASA Astrophysics Data System (ADS)

Lau, K. Y.; Ng, E. K.; Abu Bakar, M. H.; Abas, A. F.; Alresheedi, M. T.; Yusoff, Z.; Mahdi, M. A.

2018-04-01

We demonstrate a passively mode-locked erbium-doped fiber laser in L-band wavelength region with low mode-locking threshold employing a 1425 nm pump wavelength. The mode-locking regime is generated by microfiber-based saturable absorber using carbon nanotube-polymer composite in a ring cavity. This carbon nanotube saturable absorber shows saturation intensity of 9 MW/cm2. In this work, mode-locking laser threshold is observed at 36.4 mW pump power. At the maximum pump power of 107.6 mW, we obtain pulse duration at full-width half-maximum point of 490 fs and time bandwidth product of 0.33, which corresponds to 3-dB spectral bandwidth of 5.8 nm. The pulse repetition rate remains constant throughout the experiment at 5.8 MHz due to fixed cavity length of 35.5 m. Average output power and pulse energy of 10.8 mW and 1.92 nJ are attained respectively through a 30% laser output extracted from the mode-locked cavity. This work highlights the feasibility of attaining a low threshold mode-locked laser source to be employed as seed laser in L-band wavelength region.

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

Expectation values of twist fields and universal entanglement saturation of the free massive boson

NASA Astrophysics Data System (ADS)

Blondeau-Fournier, Olivier; Doyon, Benjamin

2017-07-01

The evaluation of vacuum expectation values (VEVs) in massive integrable quantum field theory (QFT) is a nontrivial renormalization-group ‘connection problem’—relating large and short distance asymptotics—and is in general unsolved. This is particularly relevant in the context of entanglement entropy, where VEVs of branch-point twist fields give universal saturation predictions. We propose a new method to compute VEVs of twist fields associated to continuous symmetries in QFT. The method is based on a differential equation in the continuous symmetry parameter, and gives VEVs as infinite form-factor series which truncate at two-particle level in free QFT. We verify the method by studying U(1) twist fields in free models, which are simply related to the branch-point twist fields. We provide the first exact formulae for the VEVs of such fields in the massive uncompactified free boson model, checking against an independent calculation based on angular quantization. We show that logarithmic terms, overlooked in the original work of Callan and Wilczek (1994 Phys. Lett. B 333 55-61), appear both in the massless and in the massive situations. This implies that, in agreement with numerical form-factor observations by Bianchini and Castro-Alvaredo (2016 Nucl. Phys. B 913 879-911), the standard power-law short-distance behavior is corrected by a logarithmic factor. We discuss how this gives universal formulae for the saturation of entanglement entropy of a single interval in near-critical harmonic chains, including loglog corrections.

Analogies between the torque-free motion of a rigid body about a fixed point and light propagation in anisotropic media

NASA Astrophysics Data System (ADS)

Bellver-Cebreros, Consuelo; Rodriguez-Danta, Marcelo

2009-03-01

An apparently unnoticed analogy between the torque-free motion of a rotating rigid body about a fixed point and the propagation of light in anisotropic media is stated. First, a new plane construction for visualizing this torque-free motion is proposed. This method uses an intrinsic representation alternative to angular momentum and independent of the modulus of angular velocity ω. The equivalence between this plane construction and the well-known Poinsot's three-dimensional graphical procedure is also shown. From this equivalence, analogies have been found between the general plane wave equation (relation of dispersion) in anisotropic media and basic equations of torque-free motion of a rigid body about a fixed point. These analogies allow reciprocal transfer of results between optics and mechanics and, as an example, reinterpretation of the internal conical refraction phenomenon in biaxial media is carried out. This paper is intended as an interdisciplinary application of analogies for students and teachers in the context of intermediate physics courses at university level.

Sedimentological Control on Hydrate Saturation Distribution in Arctic Gas-Hydrate-Bearing Deposits

NASA Astrophysics Data System (ADS)

Behseresht, J.; Peng, Y.; Bryant, S. L.

2010-12-01

Grain size variations along with the relative rates of fluid phases migrating into the zone of hydrate stability, plays an important role in gas-hydrate distribution and its morphologic characteristics. In the Arctic, strata several meters thick containing large saturations of gas hydrate are often separated by layers containing small but nonzero hydrate saturations. Examples are Mt. Elbert, Alaska and Mallik, NW Territories. We argue that this sandwich type hydrate saturation distribution is consistent with having a gas phase saturation within the sediment when the base of gas hydrate stability zone (BGHSZ) was located above the sediment package. The volume change during hydrate formation process derives movement of fluid phases into the GHSZ. We show that this fluid movement -which is mainly governed by characteristic relative permeability curves of the host sediment-, plays a crucial role in the amount of hydrate saturation in the zone of major hydrate saturation. We develop a mechanistic model that enables estimating the final hydrate saturation from an initial gas/water saturation in sediment with known relative permeability curves. The initial gas/water saturation is predicted using variation of capillary entry pressure with depth, which in turn depends on the variation in grain-size distribution. This model provides a mechanistic approach for explaining large hydrate saturations (60%-75%) observed in zones of major hydrate saturation considering the governing characteristic relative permeability curves of the host sediments. We applied the model on data from Mount Elbert well on the Alaskan North Slope. It is shown that, assuming a cocurrent flow of gas and water into the GHSZ, such large hydrate saturations (up to 75%) cannot result from large initial gas saturations (close to 1-Sw,irr) due to limitations on water flux imposed by typical relative permeability curves. They could however result from modest initial gas saturations (ca. 40%) at which we have

["Butter, my love" joy, sorrow and rehabilitation: not simply cholesterol and saturated fatty acids].

PubMed

Caramia, G

2014-01-01

The author refers to his "love" for butter and joy to eat and enjoy, during his childhood, bread, butter and jam at a time in which butter was still made with milk from cows that grazed and/or ate the hay. Subsequently the great bitterness occurred, due to the fact that many distinguished researchers have attributed to the the saturated fatty acids (SFA) and cholesterol, abundant in butter, the origin of atherosclerotic cardio vascular diseases (CVD) epidemic exploded in North America from the years 1920-1930. This happened in spite of the fact that various data did not overlap, and also that the most famous of cardiologists, worldwide known at the time, had written and pointed out that, if such a condition were caused by saturated fat animals, a corresponding increase in their consumption in the diet would be recorded, while it had actually dropped 20 percent. The prestige of some, alongside the desire to win their case, associated to the modest epidemiological skills of the time, have led them to fall into the error of "cherry picking", i.e. to choose only those data in support of their theory while ignoring others that contradicted that, for decades, the SFA were banned by encouraging the consumption of margarine and vegetable oils. Only in recent times it has emerged from indisputable surveys, that in the diet, if an excess of SFA is harmful, even an excess of simple carbohydrates or protein or polyunsaturated fatty acids omega-6 are responsible for atherosclerotic CD. The problem is not to eliminate from the SFA diet, as they look toxic while actually in some situations are indispensable, but to reach a correct balance of all the different nutrients in the diet, and not only of the SFA, plus physical activity. Butter, then, also in the light of new and important acquisitions, was rehabilitated. This brings to mind a claim issued by Hippocrates (460-377 BC), the pioneer of Western medicine, about 2400 years ago: "If you were to give each the right amount of

Scattering and the Point Spread Function of the New Generation Space Telescope

NASA Technical Reports Server (NTRS)

Schreur, Julian J.

1996-01-01

Preliminary design work on the New Generation Space Telescope (NGST) is currently under way. This telescope is envisioned as a lightweight, deployable Cassegrain reflector with an aperture of 8 meters, and an effective focal length of 80 meters. It is to be folded into a small-diameter package for launch by an Atlas booster, and unfolded in orbit. The primary is to consist of an octagon with a hole at the center, and with eight segments arranged in a flower petal configuration about the octagon. The comers of the petal-shaped segments are to be trimmed so that the package will fit atop the Atlas booster. This mirror, along with its secondary will focus the light from a point source into an image which is spread from a point by diffraction effects, figure errors, and scattering of light from the surface. The distribution of light in the image of a point source is called a point spread function (PSF). The obstruction of the incident light by the secondary mirror and its support structure, the trimmed corners of the petals, and the grooves between the segments all cause the diffraction pattern characterizing an ideal point spread function to be changed, with the trimmed comers causing the rings of the Airy pattern to become broken up, and the linear grooves causing diffraction spikes running radially away from the central spot, or Airy disk. Any figure errors the mirror segments may have, or any errors in aligning the petals with the central octagon will also spread the light out from the ideal point spread function. A point spread function for a mirror the size of the NGST and having an incident wavelength of 900 nm is considered. Most of the light is confined in a circle with a diameter of 0.05 arc seconds. The ring pattern ranges in intensity from 10(exp -2) near the center to 10(exp -6) near the edge of the plotted field, and can be clearly discerned in a log plot of the intensity. The total fraction of the light scattered from this point spread function is called

Experimental and numerical study on thermal conductivity of partially saturated unconsolidated sands

NASA Astrophysics Data System (ADS)

Lee, Youngmin; Keehm, Youngseuk; Kim, Seong-Kyun; Shin, Sang Ho

2016-04-01

A class of problems in heat flow applications requires an understanding of how water saturation affects thermal conductivity in the shallow subsurface. We conducted a series of experiments using a sand box to evaluate thermal conductivity (TC) of partially saturated unconsolidated sands under varying water saturation (Sw). We first saturated sands fully with water and varied water saturation by drainage through the bottom of the sand box. Five water-content sensors were integrated vertically into the sand box to monitor water saturation changes and a needle probe was embedded to measure thermal conductivity of partially saturated sands. The experimental result showed that thermal conductivity decreases from 2.5 W/mK for fully saturated sands to 0.7 W/mK when water saturation is 5%. We found that the decreasing trend is quite non-linear: highly sensitive at very high and low water saturations. However, the boundary effects on the top and the bottom of the sand box seemed to be responsible for this high nonlinearity. We also found that the determination of water saturation is quite important: the saturation by averaging values from all five sensors and that from the sensor at the center position, showed quite different trends in the TC-Sw domain. In parallel, we conducted a pore-scale numerical modeling, which consists of the steady-state two-phase Lattice-Boltzmann simulator and FEM thermal conduction simulator on digital pore geometry of sand aggregation. The simulation results showed a monotonous decreasing trend, and are reasonably well matched with experimental data when using average water saturations. We concluded that thermal conductivity would decrease smoothly as water saturation decreases if we can exclude boundary effects. However, in dynamic conditions, i.e. imbibition or drainage, the thermal conductivity might show hysteresis, which can be investigated with pore-scale numerical modeling with unsteady-state two-phase flow simulators in our future work.

Low-Power Photoplethysmogram Acquisition Integrated Circuit with Robust Light Interference Compensation

PubMed Central

Kim, Jongpal; Kim, Jihoon; Ko, Hyoungho

2015-01-01

To overcome light interference, including a large DC offset and ambient light variation, a robust photoplethysmogram (PPG) readout chip is fabricated using a 0.13-μm complementary metal–oxide–semiconductor (CMOS) process. Against the large DC offset, a saturation detection and current feedback circuit is proposed to compensate for an offset current of up to 30 μA. For robustness against optical path variation, an automatic emitted light compensation method is adopted. To prevent ambient light interference, an alternating sampling and charge redistribution technique is also proposed. In the proposed technique, no additional power is consumed, and only three differential switches and one capacitor are required. The PPG readout channel consumes 26.4 μW and has an input referred current noise of 260 pArms. PMID:26729122

VERTICAL INTEGRATION OF THREE-PHASE FLOW EQUATIONS FOR ANALYSIS OF LIGHT HYDROCARBON PLUME MOVEMENT

EPA Science Inventory

A mathematical model is derived for areal flow of water and light hydrocarbon in the presence of gas at atmospheric pressure. Closed-form expressions for the vertically integrated constitutive relations are derived based on a three-phase extension of the Brooks-Corey saturation-...

Passive lighting responsive three-dimensional integral imaging

NASA Astrophysics Data System (ADS)

Lou, Yimin; Hu, Juanmei

2017-11-01

A three dimensional (3D) integral imaging (II) technique with a real-time passive lighting responsive ability and vivid 3D performance has been proposed and demonstrated. Some novel lighting responsive phenomena, including light-activated 3D imaging, and light-controlled 3D image scaling and translation, have been realized optically without updating images. By switching the on/off state of a point light source illuminated on the proposed II system, the 3D images can show/hide independent of the diffused illumination background. By changing the position or illumination direction of the point light source, the position and magnification of the 3D image can be modulated in real time. The lighting responsive mechanism of the 3D II system is deduced analytically and verified experimentally. A flexible thin film lighting responsive II system with a 0.4 mm thickness was fabricated. This technique gives some additional degrees of freedom in order to design the II system and enable the virtual 3D image to interact with the real illumination environment in real time.

Electronic transport in disordered chains with saturable nonlinearity

NASA Astrophysics Data System (ADS)

dos Santos, J. L. L.; Nguyen, Ba Phi; de Moura, F. A. B. F.

2015-10-01

In this work we study numerically the dynamics of an initially localized wave packet in one-dimensional disordered chains with saturable nonlinearity. By using the generalized discrete nonlinear Schrödinger equation, we calculate two different physical quantities as a function of time, which are the participation number and the mean square displacement from the excitation site. From detailed numerical analysis, we find that the saturable nonlinearity can promote a sub-diffusive spreading of the wave packet even in the presence of diagonal disorder for a long time. In addition, we also investigate the effect of the saturated nonlinearity for initial times of the electronic evolution thus showing the possibility of mobile breather-like modes.

Density dependence of the saturated velocity in graphene

NASA Astrophysics Data System (ADS)

Ferry, D. K.

2016-11-01

The saturated velocity of a semiconductor is an important measure in bench-marking performance for either logic or microwave applications. Graphene has been of interest for such applications due to its apparently high value of the saturated velocity. Recent experiments have suggested that this value is very density dependent and can even exceed the band limiting Fermi velocity. Some of these measurements have also suggested that the scattering is dominated by the low energy surface polar mode of the SiO2 substrate. Here, we show that the saturated velocity of graphene on SiO2 is relatively independent of the density and that the scattering is dominated by the high energy surface polar mode of the substrate.

Radiative Energy Budgets of Phototrophic Surface-Associated Microbial Communities and their Photosynthetic Efficiency Under Diffuse and Collimated Light.

PubMed

Lichtenberg, Mads; Brodersen, Kasper E; Kühl, Michael

2017-01-01

We investigated the radiative energy budgets of a heterogeneous photosynthetic coral reef sediment and a compact uniform cyanobacterial biofilm on top of coastal sediment. By combining electrochemical, thermocouple and fiber-optic microsensor measurements of O 2 , temperature and light, we could calculate the proportion of the absorbed light energy that was either dissipated as heat or conserved by photosynthesis. We show, across a range of different incident light regimes, that such radiative energy budgets are highly dominated by heat dissipation constituting up to 99.5% of the absorbed light energy. Highest photosynthetic energy conservation efficiency was found in the coral sediment under low light conditions and amounted to 18.1% of the absorbed light energy. Additionally, the effect of light directionality, i.e., diffuse or collimated light, on energy conversion efficiency was tested on the two surface-associated systems. The effects of light directionality on the radiative energy budgets of these phototrophic communities were not unanimous but, resulted in local spatial differences in heat-transfer, gross photosynthesis, and light distribution. The light acclimation index, E k , i.e., the irradiance at the onset of saturation of photosynthesis, was >2 times higher in the coral sediment compared to the biofilm and changed the pattern of photosynthetic energy conservation under light-limiting conditions. At moderate to high incident irradiances, the photosynthetic conservation of absorbed energy was highest in collimated light; a tendency that changed in the biofilm under sub-saturating incident irradiances, where higher photosynthetic efficiencies were observed under diffuse light. The aim was to investigate how the physical structure and light propagation affected energy budgets and light utilization efficiencies in loosely organized vs. compact phototrophic sediment under diffuse and collimated light. Our results suggest that the optical properties and the

Radiative Energy Budgets of Phototrophic Surface-Associated Microbial Communities and their Photosynthetic Efficiency Under Diffuse and Collimated Light

PubMed Central

Lichtenberg, Mads; Brodersen, Kasper E.; Kühl, Michael

2017-01-01

We investigated the radiative energy budgets of a heterogeneous photosynthetic coral reef sediment and a compact uniform cyanobacterial biofilm on top of coastal sediment. By combining electrochemical, thermocouple and fiber-optic microsensor measurements of O2, temperature and light, we could calculate the proportion of the absorbed light energy that was either dissipated as heat or conserved by photosynthesis. We show, across a range of different incident light regimes, that such radiative energy budgets are highly dominated by heat dissipation constituting up to 99.5% of the absorbed light energy. Highest photosynthetic energy conservation efficiency was found in the coral sediment under low light conditions and amounted to 18.1% of the absorbed light energy. Additionally, the effect of light directionality, i.e., diffuse or collimated light, on energy conversion efficiency was tested on the two surface-associated systems. The effects of light directionality on the radiative energy budgets of these phototrophic communities were not unanimous but, resulted in local spatial differences in heat-transfer, gross photosynthesis, and light distribution. The light acclimation index, Ek, i.e., the irradiance at the onset of saturation of photosynthesis, was >2 times higher in the coral sediment compared to the biofilm and changed the pattern of photosynthetic energy conservation under light-limiting conditions. At moderate to high incident irradiances, the photosynthetic conservation of absorbed energy was highest in collimated light; a tendency that changed in the biofilm under sub-saturating incident irradiances, where higher photosynthetic efficiencies were observed under diffuse light. The aim was to investigate how the physical structure and light propagation affected energy budgets and light utilization efficiencies in loosely organized vs. compact phototrophic sediment under diffuse and collimated light. Our results suggest that the optical properties and the

Pronounced gradients of light, photosynthesis and O2 consumption in the tissue of the brown alga Fucus serratus.

PubMed

Lichtenberg, Mads; Kühl, Michael

2015-08-01

Macroalgae live in an ever-changing light environment affected by wave motion, self-shading and light-scattering effects, and on the thallus scale, gradients of light and chemical parameters influence algal photosynthesis. However, the thallus microenvironment and internal gradients remain underexplored. In this study, microsensors were used to quantify gradients of light, O2 concentration, variable chlorophyll fluorescence, photosynthesis and O2 consumption as a function of irradiance in the cortex and medulla layers of Fucus serratus. The two cortex layers showed more efficient light utilization compared to the medulla, calculated both from electron transport rates through photosystem II and from photosynthesis-irradiance curves. At moderate irradiance, the upper cortex exhibited onset of photosynthetic saturation, whereas lower thallus layers exhibited net O2 consumption. O2 consumption rates in light varied with depth and irradiance and were more than two-fold higher than dark respiration. We show that the thallus microenvironment of F. serratus exhibits a highly stratified balance of production and consumption of O2 , and when the frond was held in a fixed position, high incident irradiance levels on the upper cortex did not saturate photosynthesis in the lower thallus layers. We discuss possible photoadaptive responses and consequences for optimizing photosynthetic activity on the basis of vertical differences in light attenuation coefficients. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Beyond the Natural Proteome: Nondegenerate Saturation Mutagenesis-Methodologies and Advantages.

PubMed

Ferreira Amaral, M M; Frigotto, L; Hine, A V

2017-01-01

Beyond the natural proteome, high-throughput mutagenesis offers the protein engineer an opportunity to "tweak" the wild-type activity of a protein to create a recombinant protein with required attributes. Of the various approaches available, saturation mutagenesis is one of the core techniques employed by protein engineers, and in recent times, nondegenerate saturation mutagenesis is emerging as the approach of choice. This review compares the current methodologies available for conducting nondegenerate saturation mutagenesis with traditional, degenerate saturation and briefly outlines the options available for screening the resulting libraries, to discover a novel protein with the required activity and/or specificity. © 2017 Elsevier Inc. All rights reserved.

The influence of environmental P(O(2)) on hemoglobin oxygen saturation in developing zebrafish Danio rerio.

PubMed

Grillitsch, Sandra; Medgyesy, Nikolaus; Schwerte, Thorsten; Pelster, Bernd

2005-01-01

Several studies suggest that during early larval development of lower vertebrates convective blood flow is not essential to supply oxygen to the tissues, but information about the oxygenation status of larvae during the time of cutaneous respiration is still missing. If convective oxygen transport contributes to the oxygen supply to tissues, venous blood in the central circulatory system should be partly deoxygenated, and hyperoxia should increase the oxygen saturation of the hemoglobin. To analyze the changes in hemoglobin oxygen saturation induced by hyperoxic incubation, zebrafish larvae were incubated in a tiny chamber between polytetrafluoroethylene membranes (Teflon), so that the oxygen supply could be rapidly modified. Hemoglobin oxygen saturation was measured in vivo by combining video imaging techniques with a spectrophotometrical analysis of hemoglobin light absorption at specific wavelengths for maximal absorption of oxygenated and deoxygenated blood (413 nm and 431 nm, respectively) under normoxic conditions and after a 10 min period of hyperoxia (P(O(2))=100 kPa), assuming that at a P(O(2)) of 100 kPa the hemoglobin is fully saturated. The results demonstrated that red blood cell oxygenation of zebrafish larvae at 4 days post fertilization (d.p.f.), 5 d.p.f. and 12 d.p.f. could be increased by hyperoxia. The data suggest that at the time of yolk sac degradation (i.e. 4 d.p.f. and 5 d.p.f.), when the total surface area of the animal is reduced, bulk diffusion of oxygen may not be sufficient to prevent a partial deoxygenation of the hemoglobin. The decrease in hemoglobin oxygenation observed at 12 d.p.f. confirms earlier studies indicating that at 12-14 d.p.f., convective oxygen transport becomes necessary to ensure oxygen supply to the growing tissues.

The study of membrane formation via phase inversion method by cloud point and light scattering experiment

NASA Astrophysics Data System (ADS)

Arahman, Nasrul; Maimun, Teuku; Mukramah, Syawaliah

2017-01-01

The composition of polymer solution and the methods of membrane preparation determine the solidification process of membrane. The formation of membrane structure prepared via non-solvent induced phase separation (NIPS) method is mostly determined by phase separation process between polymer, solvent, and non-solvent. This paper discusses the phase separation process of polymer solution containing Polyethersulfone (PES), N-methylpirrolidone (NMP), and surfactant Tetronic 1307 (Tet). Cloud point experiment is conducted to determine the amount of non-solvent needed on induced phase separation. Amount of water required as a non-solvent decreases by the addition of surfactant Tet. Kinetics of phase separation for such system is studied by the light scattering measurement. With the addition of Tet., the delayed phase separation is observed and the structure growth rate decreases. Moreover, the morphology of fabricated membrane from those polymer systems is analyzed by scanning electron microscopy (SEM). The images of both systems show the formation of finger-like macrovoids through the cross-section.

Intermittent episodes of bright light suppress myopia in the chicken more than continuous bright light.

PubMed

Lan, Weizhong; Feldkaemper, Marita; Schaeffel, Frank

2014-01-01

Bright light has been shown a powerful inhibitor of myopia development in animal models. We studied which temporal patterns of bright light are the most potent in suppressing deprivation myopia in chickens. Eight-day-old chickens wore diffusers over one eye to induce deprivation myopia. A reference group (n = 8) was kept under office-like illuminance (500 lux) at a 10:14 light:dark cycle. Episodes of bright light (15 000 lux) were super-imposed on this background as follows. Paradigm I: exposure to constant bright light for either 1 hour (n = 5), 2 hours (n = 5), 5 hours (n = 4) or 10 hours (n = 4). Paradigm II: exposure to repeated cycles of bright light with 50% duty cycle and either 60 minutes (n = 7), 30 minutes (n = 8), 15 minutes (n = 6), 7 minutes (n = 7) or 1 minute (n = 7) periods, provided for 10 hours. Refraction and axial length were measured prior to and immediately after the 5-day experiment. Relative changes were analyzed by paired t-tests, and differences among groups were tested by one-way ANOVA. Compared with the reference group, exposure to continuous bright light for 1 or 2 hours every day had no significant protective effect against deprivation myopia. Inhibition of myopia became significant after 5 hours of bright light exposure but extending the duration to 10 hours did not offer an additional benefit. In comparison, repeated cycles of 1:1 or 7:7 minutes of bright light enhanced the protective effect against myopia and could fully suppress its development. The protective effect of bright light depends on the exposure duration and, to the intermittent form, the frequency cycle. Compared to the saturation effect of continuous bright light, low frequency cycles of bright light (1:1 min) provided the strongest inhibition effect. However, our quantitative results probably might not be directly translated into humans, but rather need further amendments in clinical studies.

An organic dye-polymer (phenol red-poly (vinyl alcohol)) composite architecture towards tunable -optical and -saturable absorption characteristics

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

Sreedhar, Sreeja, E-mail: sreejasreedhar83@gmail.com; Muneera, C. I., E-mail: drcimuneera@hotmail.com; Illyaskutty, Navas

2016-05-21

Herein, we demonstrate that blending an organic dye (guest/filler), with a vinyl polymer (host template), is an inexpensive and simple approach for the fabrication of multifunctional photonic materials which could display an enhancement in the desirable properties of the constituent materials and, at the same time provide novel synergistic properties for the guest-host system. A new guest-host nanocomposite system comprising Phenol Red dye and poly (vinyl alcohol) as guest and host template, respectively, which exhibits tunable optical characteristics and saturable absorption behavior, is introduced. The dependence of local electronic environment provided by the polymer template and the interactions of themore » polymer molecules with the encapsulated guest molecules on the observed optical/nonlinear absorption behavior is discussed. An understanding of the tunability of the optical/ photophysical processes, with respect to the filler content, as discussed herein could help in the design of improved optical materials for several photonic device applications like organic light emitting diodes and saturable absorbers.« less

Enrichment of light hydrocarbon mixture

DOEpatents

Yang, Dali [Los Alamos, NM; Devlin, David [Santa Fe, NM; Barbero, Robert S [Santa Cruz, NM; Carrera, Martin E [Naperville, IL; Colling, Craig W [Warrenville, IL

2011-11-29

Light hydrocarbon enrichment is accomplished using a vertically oriented distillation column having a plurality of vertically oriented, nonselective micro/mesoporous hollow fibers. Vapor having, for example, both propylene and propane is sent upward through the distillation column in between the hollow fibers. Vapor exits neat the top of the column and is condensed to form a liquid phase that is directed back downward through the lumen of the hollow fibers. As vapor continues to ascend and liquid continues to countercurrently descend, the liquid at the bottom of the column becomes enriched in a higher boiling point, light hydrocarbon (propane, for example) and the vapor at the top becomes enriched in a lower boiling point light hydrocarbon (propylene, for example). The hollow fiber becomes wetted with liquid during the process.

Enrichment of light hydrocarbon mixture

DOEpatents

Yang,; Dali, [Los Alamos, NM; Devlin, David [Santa Fe, NM; Barbero, Robert S [Santa Cruz, NM; Carrera, Martin E [Naperville, IL; Colling, Craig W [Warrenville, IL

2010-08-10

Light hydrocarbon enrichment is accomplished using a vertically oriented distillation column having a plurality of vertically oriented, nonselective micro/mesoporous hollow fibers. Vapor having, for example, both propylene and propane is sent upward through the distillation column in between the hollow fibers. Vapor exits neat the top of the column and is condensed to form a liquid phase that is directed back downward through the lumen of the hollow fibers. As vapor continues to ascend and liquid continues to countercurrently descend, the liquid at the bottom of the column becomes enriched in a higher boiling point, light hydrocarbon (propane, for example) and the vapor at the top becomes enriched in a lower boiling point light hydrocarbon (propylene, for example). The hollow fiber becomes wetted with liquid during the process.

Effect of the inclusion time of dietary saturated and unsaturated fats before slaughter on the accumulation and composition of abdominal fat in female broiler chickens.

PubMed

Sanz, M; Lopez-Bote, C J; Flores, A; Carmona, J M

2000-09-01

The aim of this experiment was to assess the effects of four different feeding programs designed to include tallow, a saturated fat at 0, 8, 12, and 28 d prior to slaughter on female broiler performance and the deposition, fatty acid profile, and melting point of abdominal fat. The following treatment groups were established according to dietary inclusion--from 21 to 49 d of age--of: sunflower oil (SUN), sunflower oil followed by tallow during the last 8 d (SUN + 8TALL), sunflower oil followed by tallow during the last 12 d (SUN + 12TALL), and tallow (TALL). The diets were designed to be isoenergetic and isonitrogenous. Abdominal fat deposition increased linearly with increasing number of days in which birds were fed the tallow-enriched diet. However, linear and quadratic response patterns were found between days before slaughter in which the birds were fed the tallow-enriched diet and abdominal fat melting points. This result suggested an exponential response in which 85% of the maximum level was already attained when the dietary fat type changed from an unsaturated to a saturated condition during the last 8 d of the feeding period. The use of an unsaturated fat source during the first stages of growth, and the substitution of a saturated fat for a few days before slaughter, may offer the advantage of lower abdominal fat deposition and an acceptable fat fluidity compared with the use of a saturated fat source during the whole growing and finishing period.

A Review of Multidimensional, Multifluid Intermediate-scale Experiments: Flow Behavior, Saturation Imaging, and Tracer Detection and Quantification

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

Oostrom, Mart; Dane, J. H.; Wietsma, Thomas W.

2007-08-01

A review is presented of original multidimensional, intermediate-scale experiments involving non-aqueous phase liquid (NAPL) flow behavior, imaging, and detection/quantification with solute tracers. In a companion paper (Oostrom, M., J.H. Dane, and T.W. Wietsma. 2006. A review of multidimensional, multifluid intermediate-scale experiments: Nonaqueous phase dissolution and enhanced remediation. Vadose Zone Journal 5:570-598) experiments related to aqueous dissolution and enhanced remediation were discussed. The experiments investigating flow behavior include infiltration and redistribution experiments with both light and dense NAPLs in homogeneous and heterogeneous porous medium systems. The techniques used for NAPL saturation mapping for intermediate-scale experiments include photon-attenuation methods such as gammamore » and X-ray techniques, and photographic methods such as the light reflection, light transmission, and multispectral image analysis techniques. Solute tracer methods used for detection and quantification of NAPL in the subsurface are primarily limited to variations of techniques comparing the behavior of conservative and partitioning tracers. Besides a discussion of the experimental efforts, recommendations for future research at this laboratory scale are provided.« less

Saturated phosphatidic acids mediate saturated fatty acid-induced vascular calcification and lipotoxicity.

PubMed

Masuda, Masashi; Miyazaki-Anzai, Shinobu; Keenan, Audrey L; Okamura, Kayo; Kendrick, Jessica; Chonchol, Michel; Offermanns, Stefan; Ntambi, James M; Kuro-O, Makoto; Miyazaki, Makoto

2015-10-26

Recent evidence indicates that saturated fatty acid-induced (SFA-induced) lipotoxicity contributes to the pathogenesis of cardiovascular and metabolic diseases; however, the molecular mechanisms that underlie SFA-induced lipotoxicity remain unclear. Here, we have shown that repression of stearoyl-CoA desaturase (SCD) enzymes, which regulate the intracellular balance of SFAs and unsaturated FAs, and the subsequent accumulation of SFAs in vascular smooth muscle cells (VSMCs), are characteristic events in the development of vascular calcification. We evaluated whether SMC-specific inhibition of SCD and the resulting SFA accumulation plays a causative role in the pathogenesis of vascular calcification and generated mice with SMC-specific deletion of both Scd1 and Scd2. Mice lacking both SCD1 and SCD2 in SMCs displayed severe vascular calcification with increased ER stress. Moreover, we employed shRNA library screening and radiolabeling approaches, as well as in vitro and in vivo lipidomic analysis, and determined that fully saturated phosphatidic acids such as 1,2-distearoyl-PA (18:0/18:0-PA) mediate SFA-induced lipotoxicity and vascular calcification. Together, these results identify a key lipogenic pathway in SMCs that mediates vascular calcification.

Growth and photosynthetic responses of wheat plants grown in space

NASA Technical Reports Server (NTRS)

Tripathy, B. C.; Brown, C. S.; Levine, H. G.; Krikorian, A. D.

1996-01-01

Growth and photosynthesis of wheat (Triticum aestivum L. cv Super Dwarf) plants grown onboard the space shuttle Discovery for 10 d were examined. Compared to ground control plants, the shoot fresh weight of space-grown seedlings decreased by 25%. Postflight measurements of the O2 evolution/photosynthetic photon flux density response curves of leaf samples revealed that the CO2-saturated photosynthetic rate at saturating light intensities in space-grown plants declined 25% relative to the rate in ground control plants. The relative quantum yield of CO2-saturated photosynthetic O2 evolution measured at limiting light intensities was not significantly affected. In space-grown plants, the light compensation point of the leaves increased by 33%, which likely was due to an increase (27%) in leaf dark-respiration rates. Related experiments with thylakoids isolated from space-grown plants showed that the light-saturated photosynthetic electron transport rate from H2O through photosystems II and I was reduced by 28%. These results demonstrate that photosynthetic functions are affected by the microgravity environment.

QED cascade saturation in extreme high fields.

PubMed

Luo, Wen; Liu, Wei-Yuan; Yuan, Tao; Chen, Min; Yu, Ji-Ye; Li, Fei-Yu; Del Sorbo, D; Ridgers, C P; Sheng, Zheng-Ming

2018-05-30

Upcoming ultrahigh power lasers at 10 PW level will make it possible to experimentally explore electron-positron (e - e + ) pair cascades and subsequent relativistic e - e + jets formation, which are supposed to occur in extreme astrophysical environments, such as black holes, pulsars, quasars and gamma-ray bursts. In the latter case it is a long-standing question as to how the relativistic jets are formed and what their temperatures and compositions are. Here we report simulation results of pair cascades in two counter-propagating QED-strong laser fields. A scaling of QED cascade growth with laser intensity is found, showing clear cascade saturation above threshold intensity of ~10 24 W/cm 2 . QED cascade saturation leads to pair plasma cooling and longitudinal compression along the laser axis, resulting in the subsequent formation of relativistic dense e - e + jets along transverse directions. Such laser-driven QED cascade saturation may open up the opportunity to study energetic astrophysical phenomena in laboratory.

Chlorophyll fluorescence and CO(2) assimilation of black spruce seedlings following frost in different temperature and light conditions.

PubMed

Lamontagne, M.; Bigras, F. J.; Margolis, H. A.

2000-03-01

Effects of artificial frosts on light-saturated photosynthesis (A(max)) and ground, maximal and variable fluorescence variables (F(o), F(m), and F(v) and F(v)/F(m)) were monitored on 1-year-old foliage of black spruce seedlings (Picea mariana (Mill.) BSP) grown at high (25 degrees C), moderate (15 degrees C) and low (5 degrees C) temperatures and moderate (240 &mgr;mol m(-2) s(-1)) and low (80 &mgr;mol m(-2) s(-1)) irradiances. Photoinhibition of 1-year-old foliage was greater in seedlings grown in moderate light than in seedlings grown in low light. Photoinhibition increased with decreasing growth chamber temperature at both irradiances. Most changes in F(v)/F(m) were caused by changes in F(v). Exposure to -4 degrees C decreased both F(v)/F(m) and A(max) compared with control values. The effect of the -4 degrees C frost treatment was greater in seedlings grown in low light than in seedlings grown in moderate light, probably because seedlings grown in moderate light were already partially photoinhibited before the frost treatment. Following -4 degrees C treatment, neither F(v)/F(m) nor A(max) recovered in seedlings grown in low light. Light-saturated photosynthesis decreased with decreasing growth chamber temperature. Light-saturated photosynthesis was more sensitive to the -3 and -4 degrees C frost treatments in seedlings grown at 25 degrees C than in seedlings grown at 15 and 5 degrees C. The A(max) of seedlings grown at 15 degrees C was sensitive only to the -4 degrees C frost treatment, whereas A(max) of seedlings grown at 5 degrees C was not sensitive to any of the frost treatments. Recovery of A(max) following frost took longer in seedlings grown at high temperatures than in seedlings grown at low temperatures. For seedlings grown at the same temperature but under different irradiances, both A(max) and F(v)/F(m) reflected damage to the photosynthetic system following a moderate frost. However, for seedlings grown at the same irradiance but different

Intermittent Episodes of Bright Light Suppress Myopia in the Chicken More than Continuous Bright Light

PubMed Central

Lan, Weizhong; Feldkaemper, Marita; Schaeffel, Frank

2014-01-01

Purpose Bright light has been shown a powerful inhibitor of myopia development in animal models. We studied which temporal patterns of bright light are the most potent in suppressing deprivation myopia in chickens. Methods Eight-day-old chickens wore diffusers over one eye to induce deprivation myopia. A reference group (n = 8) was kept under office-like illuminance (500 lux) at a 10∶14 light∶dark cycle. Episodes of bright light (15 000 lux) were super-imposed on this background as follows. Paradigm I: exposure to constant bright light for either 1 hour (n = 5), 2 hours (n = 5), 5 hours (n = 4) or 10 hours (n = 4). Paradigm II: exposure to repeated cycles of bright light with 50% duty cycle and either 60 minutes (n = 7), 30 minutes (n = 8), 15 minutes (n = 6), 7 minutes (n = 7) or 1 minute (n = 7) periods, provided for 10 hours. Refraction and axial length were measured prior to and immediately after the 5-day experiment. Relative changes were analyzed by paired t-tests, and differences among groups were tested by one-way ANOVA. Results Compared with the reference group, exposure to continuous bright light for 1 or 2 hours every day had no significant protective effect against deprivation myopia. Inhibition of myopia became significant after 5 hours of bright light exposure but extending the duration to 10 hours did not offer an additional benefit. In comparison, repeated cycles of 1∶1 or 7∶7 minutes of bright light enhanced the protective effect against myopia and could fully suppress its development. Conclusions The protective effect of bright light depends on the exposure duration and, to the intermittent form, the frequency cycle. Compared to the saturation effect of continuous bright light, low frequency cycles of bright light (1∶1 min) provided the strongest inhibition effect. However, our quantitative results probably might not be directly translated into humans, but rather need further amendments in clinical

Simulation of water-table aquifers using specified saturated thickness

USGS Publications Warehouse

Sheets, Rodney A.; Hill, Mary C.; Haitjema, Henk M.; Provost, Alden M.; Masterson, John P.

2014-01-01

Simulating groundwater flow in a water-table (unconfined) aquifer can be difficult because the saturated thickness available for flow depends on model-calculated hydraulic heads. It is often possible to realize substantial time savings and still obtain accurate head and flow solutions by specifying an approximate saturated thickness a priori, thus linearizing this aspect of the model. This specified-thickness approximation often relies on the use of the “confined” option in numerical models, which has led to confusion and criticism of the method. This article reviews the theoretical basis for the specified-thickness approximation, derives an error analysis for relatively ideal problems, and illustrates the utility of the approximation with a complex test problem. In the transient version of our complex test problem, the specified-thickness approximation produced maximum errors in computed drawdown of about 4% of initial aquifer saturated thickness even when maximum drawdowns were nearly 20% of initial saturated thickness. In the final steady-state version, the approximation produced maximum errors in computed drawdown of about 20% of initial aquifer saturated thickness (mean errors of about 5%) when maximum drawdowns were about 35% of initial saturated thickness. In early phases of model development, such as during initial model calibration efforts, the specified-thickness approximation can be a very effective tool to facilitate convergence. The reduced execution time and increased stability obtained through the approximation can be especially useful when many model runs are required, such as during inverse model calibration, sensitivity and uncertainty analyses, multimodel analysis, and development of optimal resource management scenarios.

Color and emotion: effects of hue, saturation, and brightness.

PubMed

Wilms, Lisa; Oberfeld, Daniel

2017-06-13

Previous studies on emotional effects of color often failed to control all the three perceptual dimensions of color: hue, saturation, and brightness. Here, we presented a three-dimensional space of chromatic colors by independently varying hue (blue, green, red), saturation (low, medium, high), and brightness (dark, medium, bright) in a factorial design. The 27 chromatic colors, plus 3 brightness-matched achromatic colors, were presented via an LED display. Participants (N = 62) viewed each color for 30 s and then rated their current emotional state (valence and arousal). Skin conductance and heart rate were measured continuously. The emotion ratings showed that saturated and bright colors were associated with higher arousal. The hue also had a significant effect on arousal, which increased from blue and green to red. The ratings of valence were the highest for saturated and bright colors, and also depended on the hue. Several interaction effects of the three color dimensions were observed for both arousal and valence. For instance, the valence ratings were higher for blue than for the remaining hues, but only for highly saturated colors. Saturated and bright colors caused significantly stronger skin conductance responses. Achromatic colors resulted in a short-term deceleration in the heart rate, while chromatic colors caused an acceleration. The results confirm that color stimuli have effects on the emotional state of the observer. These effects are not only determined by the hue of a color, as is often assumed, but by all the three color dimensions as well as their interactions.

2. Light tower, view west towards Squirrel Island, south and ...

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

2. Light tower, view west towards Squirrel Island, south and east sides - Ram Island Light Station, Ram Island, south of Ocean Point & just north of Fisherman Island, marking south side of Fisherman Island Passage, Ocean Point, Lincoln County, ME

A high performance biometric signal and image processing method to reveal blood perfusion towards 3D oxygen saturation mapping

NASA Astrophysics Data System (ADS)

Imms, Ryan; Hu, Sijung; Azorin-Peris, Vicente; Trico, Michaël.; Summers, Ron

2014-03-01

Non-contact imaging photoplethysmography (PPG) is a recent development in the field of physiological data acquisition, currently undergoing a large amount of research to characterize and define the range of its capabilities. Contact-based PPG techniques have been broadly used in clinical scenarios for a number of years to obtain direct information about the degree of oxygen saturation for patients. With the advent of imaging techniques, there is strong potential to enable access to additional information such as multi-dimensional blood perfusion and saturation mapping. The further development of effective opto-physiological monitoring techniques is dependent upon novel modelling techniques coupled with improved sensor design and effective signal processing methodologies. The biometric signal and imaging processing platform (bSIPP) provides a comprehensive set of features for extraction and analysis of recorded iPPG data, enabling direct comparison with other biomedical diagnostic tools such as ECG and EEG. Additionally, utilizing information about the nature of tissue structure has enabled the generation of an engineering model describing the behaviour of light during its travel through the biological tissue. This enables the estimation of the relative oxygen saturation and blood perfusion in different layers of the tissue to be calculated, which has the potential to be a useful diagnostic tool.