High-precision branching ratio measurement for the superallowed β+ emitter Ga62

NASA Astrophysics Data System (ADS)

Finlay, P.; Ball, G. C.; Leslie, J. R.; Svensson, C. E.; Towner, I. S.; Austin, R. A. E.; Bandyopadhyay, D.; Chaffey, A.; Chakrawarthy, R. S.; Garrett, P. E.; Grinyer, G. F.; Hackman, G.; Hyland, B.; Kanungo, R.; Leach, K. G.; Mattoon, C. M.; Morton, A. C.; Pearson, C. J.; Phillips, A. A.; Ressler, J. J.; Sarazin, F.; Savajols, H.; Schumaker, M. A.; Wong, J.

2008-08-01

A high-precision branching ratio measurement for the superallowed β+ decay of Ga62 was performed at the Isotope Separator and Accelerator (ISAC) radioactive ion beam facility. The 8π spectrometer, an array of 20 high-purity germanium detectors, was employed to detect the γ rays emitted following Gamow-Teller and nonanalog Fermi β+ decays of Ga62, and the SCEPTAR plastic scintillator array was used to detect the emitted β particles. Thirty γ rays were identified following Ga62 decay, establishing the superallowed branching ratio to be 99.858(8)%. Combined with the world-average half-life and a recent high-precision Q-value measurement for Ga62, this branching ratio yields an ft value of 3074.3±1.1 s, making Ga62 among the most precisely determined superallowed ft values. Comparison between the superallowed ft value determined in this work and the world-average corrected F tmacr value allows the large nuclear-structure-dependent correction for Ga62 decay to be experimentally determined from the CVC hypothesis to better than 7% of its own value, the most precise experimental determination for any superallowed emitter. These results provide a benchmark for the refinement of the theoretical description of isospin-symmetry breaking in A⩾62 superallowed decays.

Highlight summarization in golf videos using audio signals

NASA Astrophysics Data System (ADS)

Kim, Hyoung-Gook; Kim, Jin Young

2008-01-01

In this paper, we present an automatic summarization of highlights in golf videos based on audio information alone without video information. The proposed highlight summarization system is carried out based on semantic audio segmentation and detection on action units from audio signals. Studio speech, field speech, music, and applause are segmented by means of sound classification. Swing is detected by the methods of impulse onset detection. Sounds like swing and applause form a complete action unit, while studio speech and music parts are used to anchor the program structure. With the advantage of highly precise detection of applause, highlights are extracted effectively. Our experimental results obtain high classification precision on 18 golf games. It proves that the proposed system is very effective and computationally efficient to apply the technology to embedded consumer electronic devices.

Oil defect detection of electrowetting display

NASA Astrophysics Data System (ADS)

Chiang, Hou-Chi; Tsai, Yu-Hsiang; Yan, Yung-Jhe; Huang, Ting-Wei; Mang, Ou-Yang

2015-08-01

In recent years, transparent display is an emerging topic in display technologies. Apply in many fields just like mobile device, shopping or advertising window, and etc. Electrowetting Display (EWD) is one kind of potential transparent display technology advantages of high transmittance, fast response time, high contrast and rich color with pigment based oil system. In mass production process of Electrowetting Display, oil defects should be found by Automated Optical Inspection (AOI) detection system. It is useful in determination of panel defects for quality control. According to the research of our group, we proposed a mechanism of AOI detection system detecting the different kinds of oil defects. This mechanism can detect different kinds of oil defect caused by oil overflow or material deteriorated after oil coating or driving. We had experiment our mechanism with a 6-inch Electrowetting Display panel from ITRI, using an Epson V750 scanner with 1200 dpi resolution. Two AOI algorithms were developed, which were high speed method and high precision method. In high precision method, oil jumping or non-recovered can be detected successfully. This mechanism of AOI detection system can be used to evaluate the oil uniformity in EWD panel process. In the future, our AOI detection system can be used in quality control of panel manufacturing for mass production.

Combining laser frequency combs and iodine cell calibration techniques for Doppler detection of exoplanets

NASA Astrophysics Data System (ADS)

Cahoy, Kerri; Fischer, Debra; Spronck, Julien; DeMille, David

2010-07-01

Exoplanets can be detected from a time series of stellar spectra by looking for small, periodic shifts in the absorption features that are consistent with Doppler shifts caused by the presence of an exoplanet, or multiple exoplanets, in the system. While hundreds of large exoplanets have already been discovered with the Doppler technique (also called radial velocity), our goal is to improve the measurement precision so that many Earth-like planets can be detected. The smaller mass and longer period of true Earth analogues require the ability to detect a reflex velocity of ~10 cm/s over long time periods. Currently, typical astronomical spectrographs calibrate using either Iodine absorptive cells or Thorium Argon lamps and achieve ~10 m/s precision, with the most stable spectrographs pushing down to ~2 m/s. High velocity precision is currently achieved at HARPS by controlling the thermal and pressure environment of the spectrograph. These environmental controls increase the cost of the spectrograph, and it is not feasible to simply retrofit existing spectrometers. We propose a fiber-fed high precision spectrograph design that combines the existing ~5000-6000 A Iodine calibration system with a high-precision Laser Frequency Comb (LFC) system from ~6000-7000 A that just meets the redward side of the Iodine lines. The scientific motivation for such a system includes: a 1000 A span in the red is currently achievable with LFC systems, combining the two calibration methods increases the wavelength range by a factor of two, and moving redward decreases the "noise" from starspots. The proposed LFC system design employs a fiber laser, tunable serial Fabry-Perot cavity filters to match the resolution of the LFC system to that of standard astronomical spectrographs, and terminal ultrasonic vibration of the multimode fiber for a stable point spread function.

High Precision Optical Observations of Space Debris in the Geo Ring from Venezuela

NASA Astrophysics Data System (ADS)

Lacruz, E.; Abad, C.; Downes, J. J.; Casanova, D.; Tresaco, E.

2018-01-01

We present preliminary results to demonstrate that our method for detection and location of Space Debris (SD) in the geostationary Earth orbit (GEO) ring, based on observations at the OAN of Venezuela is of high astrometric precision. A detailed explanation of the method, its validation and first results is available in (Lacruz et al. 2017).

The design of high precision temperature control system for InGaAs short-wave infrared detector

NASA Astrophysics Data System (ADS)

Wang, Zheng-yun; Hu, Yadong; Ni, Chen; Huang, Lin; Zhang, Aiwen; Sun, Xiao-bing; Hong, Jin

2018-02-01

The InGaAs Short-wave infrared detector is a temperature-sensitive device. Accurate temperature control can effectively reduce the background signal and improve detection accuracy, detection sensitivity, and the SNR of the detection system. Firstly, the relationship between temperature and detection background, NEP is analyzed, the principle of TEC and formula between cooling power, cooling current and hot-cold interface temperature difference are introduced. Then, the high precision constant current drive circuit based on triode voltage control current, and an incremental algorithm model based on deviation tracking compensation and PID control are proposed, which effectively suppresses the temperature overshoot, overcomes the temperature inertia, and has strong robustness. Finally, the detector and temperature control system are tested. Results show that: the lower of detector temperature, the smaller the temperature fluctuation, the higher the detection accuracy and the detection sensitivity. The temperature control system achieves the high temperature control with the temperature control rate is 7 8°C/min and the temperature fluctuation is better than +/-0. 04°C.

First Planet Confirmation with a Dispersed Fixed-Delay Interferometer

NASA Astrophysics Data System (ADS)

van Eyken, J. C.; Ge, J.; Mahadevan, S.; DeWitt, C.

2004-01-01

The Exoplanet Tracker is a prototype of a new type of fiber-fed instrument for performing high-precision relative Doppler measurements to detect extrasolar planets. A combination of Michelson interferometer and medium-resolution spectrograph, this low-cost instrument facilitates radial velocity measurements with high throughput over a small bandwidth (~300 Å) and has the potential to be designed for multiobject operation with moderate bandwidths (~1000 Å). We present the first planet detection with this new type of instrument, a successful confirmation of the well-established planetary companion to 51 Peg, showing an rms precision of 11.5 m s-1 over 5 days. We also show comparison measurements of the radial velocity stable star, η Cas, showing an rms precision of 7.9 m s-1 over 7 days. These new results are starting to approach the precision levels obtained with traditional radial velocity techniques based on cross-dispersed echelles. We anticipate that this new technique could have an important impact in the search for extrasolar planets.

McDonald Observatory Planetary Search - A high precision stellar radial velocity survey for other planetary systems

NASA Technical Reports Server (NTRS)

Cochran, William D.; Hatzes, Artie P.

1993-01-01

The McDonald Observatory Planetary Search program surveyed a sample of 33 nearby F, G, and K stars since September 1987 to search for substellar companion objects. Measurements of stellar radial velocity variations to a precision of better than 10 m/s were performed as routine observations to detect Jovian planets in orbit around solar type stars. Results confirm the detection of a companion object to HD114762.

A Novel Zero Velocity Interval Detection Algorithm for Self-Contained Pedestrian Navigation System with Inertial Sensors

PubMed Central

Tian, Xiaochun; Chen, Jiabin; Han, Yongqiang; Shang, Jianyu; Li, Nan

2016-01-01

Zero velocity update (ZUPT) plays an important role in pedestrian navigation algorithms with the premise that the zero velocity interval (ZVI) should be detected accurately and effectively. A novel adaptive ZVI detection algorithm based on a smoothed pseudo Wigner–Ville distribution to remove multiple frequencies intelligently (SPWVD-RMFI) is proposed in this paper. The novel algorithm adopts the SPWVD-RMFI method to extract the pedestrian gait frequency and to calculate the optimal ZVI detection threshold in real time by establishing the function relationships between the thresholds and the gait frequency; then, the adaptive adjustment of thresholds with gait frequency is realized and improves the ZVI detection precision. To put it into practice, a ZVI detection experiment is carried out; the result shows that compared with the traditional fixed threshold ZVI detection method, the adaptive ZVI detection algorithm can effectively reduce the false and missed detection rate of ZVI; this indicates that the novel algorithm has high detection precision and good robustness. Furthermore, pedestrian trajectory positioning experiments at different walking speeds are carried out to evaluate the influence of the novel algorithm on positioning precision. The results show that the ZVI detected by the adaptive ZVI detection algorithm for pedestrian trajectory calculation can achieve better performance. PMID:27669266

Multifrequency high precise subTHz-THz-IR spectroscopy for exhaled breath research

NASA Astrophysics Data System (ADS)

Vaks, Vladimir L.; Domracheva, Elena G.; Pripolzin, Sergey I.; Chernyaeva, Mariya B.

2016-09-01

Nowadays the development of analytical spectroscopy with high performance, sensitivity and spectral resolution for exhaled breath research is attended. The method of two-frequency high precise THz spectroscopy and the method of high precise subTHz-THz-IR spectroscopy are presented. Development of a subTHz-THz-IR gas analyzer increases the number of gases that can be identified and the reliability of the detection by confirming the signature in both THz and MIR ranges. The testing measurements have testified this new direction of analytical spectroscopy to open widespread trends of its using for various problems of medicine and biology. First of all, there are laboratory investigations of the processes in exhaled breath and studying of their dynamics. Besides, the methods presented can be applied for detecting intermediate and short time living products of reactions in exhaled breath. The spectrometers have been employed for investigations of acetone, methanol and ethanol in the breath samples of healthy volunteers and diabetes patients. The results have demonstrated an increased concentration of acetone in breath of diabetes patients. The dynamic of changing the acetone concentration before and after taking the medicines is discovered. The potential markers of pre-cancer states and oncological diseases of gastrointestinal tract organs have been detected. The changes in the NO concentration in exhaled breath of cancer patients during radiotherapy as well as increase of the NH3 concentration at gastrointestinal diseases have been revealed. The preliminary investigations of biomarkers in three frequency ranges have demonstrated the advantages of the multifrequency high precise spectroscopy for noninvasive medical diagnostics.

Precise measurement of the neutron magnetic form factor G(M)n in the few-GeV2 region.

PubMed

Lachniet, J; Afanasev, A; Arenhövel, H; Brooks, W K; Gilfoyle, G P; Higinbotham, D; Jeschonnek, S; Quinn, B; Vineyard, M F; Adams, G; Adhikari, K P; Amaryan, M J; Anghinolfi, M; Asavapibhop, B; Asryan, G; Avakian, H; Bagdasaryan, H; Baillie, N; Ball, J P; Baltzell, N A; Barrow, S; Batourine, V; Battaglieri, M; Beard, K; Bedlinskiy, I; Bektasoglu, M; Bellis, M; Benmouna, N; Berman, B L; Biselli, A S; Bonner, B E; Bookwalter, C; Bouchigny, S; Boiarinov, S; Bradford, R; Branford, D; Briscoe, W J; Bültmann, S; Burkert, V D; Calarco, J R; Careccia, S L; Carman, D S; Casey, L; Cheng, L; Cole, P L; Coleman, A; Collins, P; Cords, D; Corvisiero, P; Crabb, D; Crede, V; Cummings, J P; Dale, D; Daniel, A; Dashyan, N; De Masi, R; De Vita, R; De Sanctis, E; Degtyarenko, P V; Denizli, H; Dennis, L; Deur, A; Dhamija, S; Dharmawardane, K V; Dhuga, K S; Dickson, R; Djalali, C; Dodge, G E; Doughty, D; Dragovitsch, P; Dugger, M; Dytman, S; Dzyubak, O P; Egiyan, H; Egiyan, K S; El Fassi, L; Elouadrhiri, L; Empl, A; Eugenio, P; Fatemi, R; Fedotov, G; Fersch, R; Feuerbach, R J; Forest, T A; Fradi, A; Gabrielyan, M Y; Garçon, M; Gavalian, G; Gevorgyan, N; Giovanetti, K L; Girod, F X; Goetz, J T; Gohn, W; Golovatch, E; Gothe, R W; Graham, L; Griffioen, K A; Guidal, M; Guillo, M; Guler, N; Guo, L; Gyurjyan, V; Hadjidakis, C; Hafidi, K; Hakobyan, H; Hanretty, C; Hardie, J; Hassall, N; Heddle, D; Hersman, F W; Hicks, K; Hleiqawi, I; Holtrop, M; Hu, J; Huertas, M; Hyde-Wright, C E; Ilieva, Y; Ireland, D G; Ishkhanov, B S; Isupov, E L; Ito, M M; Jenkins, D; Jo, H S; Johnstone, J R; Joo, K; Juengst, H G; Kageya, T; Kalantarians, N; Keller, D; Kellie, J D; Khandaker, M; Khetarpal, P; Kim, K Y; Kim, K; Kim, W; Klein, A; Klein, F J; Klusman, M; Konczykowski, P; Kossov, M; Kramer, L H; Kubarovsky, V; Kuhn, J; Kuhn, S E; Kuleshov, S V; Kuznetsov, V; Laget, J M; Langheinrich, J; Lawrence, D; Lima, A C S; Livingston, K; Lowry, M; Lu, H Y; Lukashin, K; Maccormick, M; Malace, S; Manak, J J; Markov, N; Mattione, P; McAleer, S; McCracken, M E; McKinnon, B; McNabb, J W C; Mecking, B A; Mestayer, M D; Meyer, C A; Mibe, T; Mikhailov, K; Mineeva, T; Minehart, R; Mirazita, M; Miskimen, R; Mokeev, V; Moreno, B; Moriya, K; Morrow, S A; Moteabbed, M; Mueller, J; Munevar, E; Mutchler, G S; Nadel-Turonski, P; Nasseripour, R; Niccolai, S; Niculescu, G; Niculescu, I; Niczyporuk, B B; Niroula, M R; Niyazov, R A; Nozar, M; O'Rielly, G V; Osipenko, M; Ostrovidov, A I; Park, K; Park, S; Pasyuk, E; Paterson, C; Pereira, S Anefalos; Philips, S A; Pierce, J; Pivnyuk, N; Pocanic, D; Pogorelko, O; Polli, E; Popa, I; Pozdniakov, S; Preedom, B M; Price, J W; Prok, Y; Protopopescu, D; Qin, L M; Raue, B A; Riccardi, G; Ricco, G; Ripani, M; Ritchie, B G; Rosner, G; Rossi, P; Rowntree, D; Rubin, P D; Sabatié, F; Saini, M S; Salamanca, J; Salgado, C; Sandorfi, A; Santoro, J P; Sapunenko, V; Schott, D; Schumacher, R A; Serov, V S; Sharabian, Y G; Sharov, D; Shaw, J; Shvedunov, N V; Skabelin, A V; Smith, E S; Smith, L C; Sober, D I; Sokhan, D; Starostin, A; Stavinsky, A; Stepanyan, S; Stepanyan, S S; Stokes, B E; Stoler, P; Stopani, K A; Strakovsky, I I; Strauch, S; Suleiman, R; Taiuti, M; Taylor, S; Tedeschi, D J; Thompson, R; Tkabladze, A; Tkachenko, S; Ungaro, M; Vlassov, A V; Watts, D P; Wei, X; Weinstein, L B; Weygand, D P; Williams, M; Wolin, E; Wood, M H; Yegneswaran, A; Yun, J; Yurov, M; Zana, L; Zhang, J; Zhao, B; Zhao, Z W

2009-05-15

The neutron elastic magnetic form factor was extracted from quasielastic electron scattering on deuterium over the range Q;{2}=1.0-4.8 GeV2 with the CLAS detector at Jefferson Lab. High precision was achieved with a ratio technique and a simultaneous in situ calibration of the neutron detection efficiency. Neutrons were detected with electromagnetic calorimeters and time-of-flight scintillators at two beam energies. The dipole parametrization gives a good description of the data.

Illuminating necrosis: From mechanistic exploration to preclinical application using fluorescence molecular imaging with indocyanine green

PubMed Central

Fang, Cheng; Wang, Kun; Zeng, Chaoting; Chi, Chongwei; Shang, Wenting; Ye, Jinzuo; Mao, Yamin; Fan, Yingfang; Yang, Jian; Xiang, Nan; Zeng, Ning; Zhu, Wen; Fang, Chihua; Tian, Jie

2016-01-01

Tissue necrosis commonly accompanies the development of a wide range of serious diseases. Therefore, highly sensitive detection and precise boundary delineation of necrotic tissue via effective imaging techniques are crucial for clinical treatments; however, no imaging modalities have achieved satisfactory results to date. Although fluorescence molecular imaging (FMI) shows potential in this regard, no effective necrosis-avid fluorescent probe has been developed for clinical applications. Here, we demonstrate that indocyanine green (ICG) can achieve high avidity of necrotic tissue owing to its interaction with lipoprotein (LP) and phospholipids. The mechanism was explored at the cellular and molecular levels through a series of in vitro studies. Detection of necrotic tissue and real-time image-guided surgery were successfully achieved in different organs of different animal models with the help of FMI using in house-designed imaging devices. The results indicated that necrotic tissue with a 0.6 mm diameter could be effectively detected with precise boundary definition. We believe that the new discovery and the associated imaging techniques will improve personalized and precise surgery in the near future. PMID:26864116

DB2: a probabilistic approach for accurate detection of tandem duplication breakpoints using paired-end reads.

PubMed

Yavaş, Gökhan; Koyutürk, Mehmet; Gould, Meetha P; McMahon, Sarah; LaFramboise, Thomas

2014-03-05

With the advent of paired-end high throughput sequencing, it is now possible to identify various types of structural variation on a genome-wide scale. Although many methods have been proposed for structural variation detection, most do not provide precise boundaries for identified variants. In this paper, we propose a new method, Distribution Based detection of Duplication Boundaries (DB2), for accurate detection of tandem duplication breakpoints, an important class of structural variation, with high precision and recall. Our computational experiments on simulated data show that DB2 outperforms state-of-the-art methods in terms of finding breakpoints of tandem duplications, with a higher positive predictive value (precision) in calling the duplications' presence. In particular, DB2's prediction of tandem duplications is correct 99% of the time even for very noisy data, while narrowing down the space of possible breakpoints within a margin of 15 to 20 bps on the average. Most of the existing methods provide boundaries in ranges that extend to hundreds of bases with lower precision values. Our method is also highly robust to varying properties of the sequencing library and to the sizes of the tandem duplications, as shown by its stable precision, recall and mean boundary mismatch performance. We demonstrate our method's efficacy using both simulated paired-end reads, and those generated from a melanoma sample and two ovarian cancer samples. Newly discovered tandem duplications are validated using PCR and Sanger sequencing. Our method, DB2, uses discordantly aligned reads, taking into account the distribution of fragment length to predict tandem duplications along with their breakpoints on a donor genome. The proposed method fine tunes the breakpoint calls by applying a novel probabilistic framework that incorporates the empirical fragment length distribution to score each feasible breakpoint. DB2 is implemented in Java programming language and is freely available at http://mendel.gene.cwru.edu/laframboiselab/software.php.

Trace element analysis by EPMA in geosciences: detection limit, precision and accuracy

NASA Astrophysics Data System (ADS)

Batanova, V. G.; Sobolev, A. V.; Magnin, V.

2018-01-01

Use of the electron probe microanalyser (EPMA) for trace element analysis has increased over the last decade, mainly because of improved stability of spectrometers and the electron column when operated at high probe current; development of new large-area crystal monochromators and ultra-high count rate spectrometers; full integration of energy-dispersive / wavelength-dispersive X-ray spectrometry (EDS/WDS) signals; and the development of powerful software packages. For phases that are stable under a dense electron beam, the detection limit and precision can be decreased to the ppm level by using high acceleration voltage and beam current combined with long counting time. Data on 10 elements (Na, Al, P, Ca, Ti, Cr, Mn, Co, Ni, Zn) in olivine obtained on a JEOL JXA-8230 microprobe with tungsten filament show that the detection limit decreases proportionally to the square root of counting time and probe current. For all elements equal or heavier than phosphorus (Z = 15), the detection limit decreases with increasing accelerating voltage. The analytical precision for minor and trace elements analysed in olivine at 25 kV accelerating voltage and 900 nA beam current is 4 - 18 ppm (2 standard deviations of repeated measurements of the olivine reference sample) and is similar to the detection limit of corresponding elements. To analyse trace elements accurately requires careful estimation of background, and consideration of sample damage under the beam and secondary fluorescence from phase boundaries. The development and use of matrix reference samples with well-characterised trace elements of interest is important for monitoring and improving of the accuracy. An evaluation of the accuracy of trace element analyses in olivine has been made by comparing EPMA data for new reference samples with data obtained by different in-situ and bulk analytical methods in six different laboratories worldwide. For all elements, the measured concentrations in the olivine reference sample were found to be identical (within internal precision) to reference values, suggesting that achieved precision and accuracy are similar. The spatial resolution of EPMA in a silicate matrix, even at very extreme conditions (accelerating voltage 25 kV), does not exceed 7 - 8 μm and thus is still better than laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) or secondary ion mass spectrometry (SIMS) of similar precision. These make the electron microprobe an indispensable method with applications in experimental petrology, geochemistry and cosmochemistry.

The research of adaptive-exposure on spot-detecting camera in ATP system

NASA Astrophysics Data System (ADS)

Qian, Feng; Jia, Jian-jun; Zhang, Liang; Wang, Jian-Yu

2013-08-01

High precision acquisition, tracking, pointing (ATP) system is one of the key techniques of laser communication. The spot-detecting camera is used to detect the direction of beacon in laser communication link, so that it can get the position information of communication terminal for ATP system. The positioning accuracy of camera decides the capability of laser communication system directly. So the spot-detecting camera in satellite-to-earth laser communication ATP systems needs high precision on target detection. The positioning accuracy of cameras should be better than +/-1μ rad . The spot-detecting cameras usually adopt centroid algorithm to get the position information of light spot on detectors. When the intensity of beacon is moderate, calculation results of centroid algorithm will be precise. But the intensity of beacon changes greatly during communication for distance, atmospheric scintillation, weather etc. The output signal of detector will be insufficient when the camera underexposes to beacon because of low light intensity. On the other hand, the output signal of detector will be saturated when the camera overexposes to beacon because of high light intensity. The calculation accuracy of centroid algorithm becomes worse if the spot-detecting camera underexposes or overexposes, and then the positioning accuracy of camera will be reduced obviously. In order to improve the accuracy, space-based cameras should regulate exposure time in real time according to light intensity. The algorithm of adaptive-exposure technique for spot-detecting camera based on metal-oxide-semiconductor (CMOS) detector is analyzed. According to analytic results, a CMOS camera in space-based laser communication system is described, which utilizes the algorithm of adaptive-exposure to adapting exposure time. Test results from imaging experiment system formed verify the design. Experimental results prove that this design can restrain the reduction of positioning accuracy for the change of light intensity. So the camera can keep stable and high positioning accuracy during communication.

Investigation of Space Interferometer Control Using Imaging Sensor Output Feedback

NASA Technical Reports Server (NTRS)

Leitner, Jesse A.; Cheng, Victor H. L.

2003-01-01

Numerous space interferometry missions are planned for the next decade to verify different enabling technologies towards very-long-baseline interferometry to achieve high-resolution imaging and high-precision measurements. These objectives will require coordinated formations of spacecraft separately carrying optical elements comprising the interferometer. High-precision sensing and control of the spacecraft and the interferometer-component payloads are necessary to deliver sub-wavelength accuracy to achieve the scientific objectives. For these missions, the primary scientific product of interferometer measurements may be the only source of data available at the precision required to maintain the spacecraft and interferometer-component formation. A concept is studied for detecting the interferometer's optical configuration errors based on information extracted from the interferometer sensor output. It enables precision control of the optical components, and, in cases of space interferometers requiring formation flight of spacecraft that comprise the elements of a distributed instrument, it enables the control of the formation-flying vehicles because independent navigation or ranging sensors cannot deliver the high-precision metrology over the entire required geometry. Since the concept can act on the quality of the interferometer output directly, it can detect errors outside the capability of traditional metrology instruments, and provide the means needed to augment the traditional instrumentation to enable enhanced performance. Specific analyses performed in this study include the application of signal-processing and image-processing techniques to solve the problems of interferometer aperture baseline control, interferometer pointing, and orientation of multiple interferometer aperture pairs.

A spatial scan statistic for nonisotropic two-level risk cluster.

PubMed

Li, Xiao-Zhou; Wang, Jin-Feng; Yang, Wei-Zhong; Li, Zhong-Jie; Lai, Sheng-Jie

2012-01-30

Spatial scan statistic methods are commonly used for geographical disease surveillance and cluster detection. The standard spatial scan statistic does not model any variability in the underlying risks of subregions belonging to a detected cluster. For a multilevel risk cluster, the isotonic spatial scan statistic could model a centralized high-risk kernel in the cluster. Because variations in disease risks are anisotropic owing to different social, economical, or transport factors, the real high-risk kernel will not necessarily take the central place in a whole cluster area. We propose a spatial scan statistic for a nonisotropic two-level risk cluster, which could be used to detect a whole cluster and a noncentralized high-risk kernel within the cluster simultaneously. The performance of the three methods was evaluated through an intensive simulation study. Our proposed nonisotropic two-level method showed better power and geographical precision with two-level risk cluster scenarios, especially for a noncentralized high-risk kernel. Our proposed method is illustrated using the hand-foot-mouth disease data in Pingdu City, Shandong, China in May 2009, compared with two other methods. In this practical study, the nonisotropic two-level method is the only way to precisely detect a high-risk area in a detected whole cluster. Copyright © 2011 John Wiley & Sons, Ltd.

De-Trending K2 Exoplanet Targets for High Spacecraft Motion

NASA Astrophysics Data System (ADS)

Saunders, Nicholas; Luger, Rodrigo; Barnes, Rory

2018-01-01

After the failure of two reaction wheels, the Kepler space telescope lost its fine pointing ability and entered a new phase of observation, K2. Targets observed by K2 have high motion relative to the detector and K2 light curves have higher noise than Kepler observations. Despite the increased noise, systematics removal pipelines such as K2SFF and EVEREST have enabled continued high-precision transiting planet science with the telescope, resulting in the detection of hundreds of new exoplanets. However, as the spacecraft begins to run out of fuel, sputtering will drive large and random variations in pointing that can prevent detection of exoplanets during the remaining 5 campaigns. In general, higher motion will spread the stellar point spread function (PSF) across more pixels during a campaign, which increases the number of degrees of freedom in the noise component and significantly reduces the de-trending power of traditional systematics removal methods. We use a model of the Kepler CCD combined with pixel-level information of a large number of stars across the detector to improve the performance of the EVEREST pipeline at high motion. We also consider the problem of increased crowding for static apertures in the high-motion regime and develop pixel response function (PRF)-fitting techniques to mitigate contamination and maximize the de-trending power. We assess the performance of our code by simulating sputtering events and assessing exoplanet detection efficiency with transit injection/recovery tests. We find that targets with roll amplitudes of up to 8 pixels, approximately 15 times K2 roll, can be de-trended within 2 to 3 factors of current K2 photometric precision for stars up to 14th magnitude. Achieved recovery precision allows detection of small planets around 11th and 12th magnitude stars. These methods can be applied to the light curves of K2 targets for existing and future campaigns to ensure that precision exoplanet science can still be performed despite increased motion. We further discuss how these methods can be applied to upcoming space telescope missions, such as the Transiting Exoplanet Survey Satellite (TESS), to improve future detection and characterization of exoplanet candidates.

A high-precision radial-velocity survey for other planetary systems

NASA Technical Reports Server (NTRS)

Cochran, William D.; Hatzes, Artie P.

1994-01-01

The precise measurement of variations in stellar radial velocities provides one of several promising methods of surveying a large sample of nearby solar type stars to detect planetary systems in orbit around them. The McDonald Observatory Planetary Search (MOPS) was started in 1987 September with the goal of detecting other nearby planetary systems. A stabilized I2 gas absorption cell placed in front of the entrance slit to the McDonald Observatory 2.7 m telescope coude spectrograph serves as the velocity metric. With this I2 cell we can achieve radial velocity measurement precision better than 10 m/s in an individual measurement. At this level we can detect a Jupiter-like planet around a solar-type star, and have some hope of detecting Saturn-like planets in a long-term survey. The detectability of planets is ultimately limited by stellar pulsation modes and photospheric motions. Monthly MOPS observing runs allow us to obtain at least 5 independent observations per year of the 33 solar-type (F5-K7) stars on our observing list. We present representative results from the first five years of the survey.

Vision-based in-line fabric defect detection using yarn-specific shape features

NASA Astrophysics Data System (ADS)

Schneider, Dorian; Aach, Til

2012-01-01

We develop a methodology for automatic in-line flaw detection in industrial woven fabrics. Where state of the art detection algorithms apply texture analysis methods to operate on low-resolved ({200 ppi) image data, we describe here a process flow to segment single yarns in high-resolved ({1000 ppi) textile images. Four yarn shape features are extracted, allowing a precise detection and measurement of defects. The degree of precision reached allows a classification of detected defects according to their nature, providing an innovation in the field of automatic fabric flaw detection. The design has been carried out to meet real time requirements and face adverse conditions caused by loom vibrations and dirt. The entire process flow is discussed followed by an evaluation using a database with real-life industrial fabric images. This work pertains to the construction of an on-loom defect detection system to be used in manufacturing practice.

Moving Object Detection Using Scanning Camera on a High-Precision Intelligent Holder.

PubMed

Chen, Shuoyang; Xu, Tingfa; Li, Daqun; Zhang, Jizhou; Jiang, Shenwang

2016-10-21

During the process of moving object detection in an intelligent visual surveillance system, a scenario with complex background is sure to appear. The traditional methods, such as "frame difference" and "optical flow", may not able to deal with the problem very well. In such scenarios, we use a modified algorithm to do the background modeling work. In this paper, we use edge detection to get an edge difference image just to enhance the ability of resistance illumination variation. Then we use a "multi-block temporal-analyzing LBP (Local Binary Pattern)" algorithm to do the segmentation. In the end, a connected component is used to locate the object. We also produce a hardware platform, the core of which consists of the DSP (Digital Signal Processor) and FPGA (Field Programmable Gate Array) platforms and the high-precision intelligent holder.

Fiber Scrambling for High Precision Spectrographs

NASA Astrophysics Data System (ADS)

Kaplan, Zachary; Spronck, J. F. P.; Fischer, D.

2011-05-01

The detection of Earth-like exoplanets with the radial velocity method requires extreme Doppler precision and long-term stability in order to measure tiny reflex velocities in the host star. Recent planet searches have led to the detection of so called "super-Earths” (up to a few Earth masses) that induce radial velocity changes of about 1 m/s. However, the detection of true Earth analogs requires a precision of 10 cm/s. One of the largest factors limiting Doppler precision is variation in the Point Spread Function (PSF) from observation to observation due to changes in the illumination of the slit and spectrograph optics. Thus, this stability has become a focus of current instrumentation work. Fiber optics have been used since the 1980's to couple telescopes to high-precision spectrographs, initially for simpler mechanical design and control. However, fiber optics are also naturally efficient scramblers. Scrambling refers to a fiber's ability to produce an output beam independent of input. Our research is focused on characterizing the scrambling properties of several types of fibers, including circular, square and octagonal fibers. By measuring the intensity distribution after the fiber as a function of input beam position, we can simulate guiding errors that occur at an observatory. Through this, we can determine which fibers produce the most uniform outputs for the severest guiding errors, improving the PSF and allowing sub-m/s precision. However, extensive testing of fibers of supposedly identical core diameter, length and shape from the same manufacturer has revealed the "personality” of individual fibers. Personality describes differing intensity patterns for supposedly duplicate fibers illuminated identically. Here, we present our results on scrambling characterization as a function of fiber type, while studying individual fiber personality.

MINOS Timing and GPS Precise Point Positioning

DTIC Science & Technology

2012-01-01

Minos Timing Spec • Neutrinos created in bunches separated by 19 ns • ~ 1 neutrino/day detected in Soudan Mine – 2 milliseconds travel time...calibration – No low-cost Fermilab to Soudan Mine connections known – Not yet tested for operational time transfer Clock Options • High-Performance... UNDERGROUND LABORATORY •;, ~ (((ft.F ~’: · GPS PRECISE POINT POSITIONING A Brief Overview What is GPS PPP? • GPS PPP is a way to use precise ephemerides

Gas Chromatic Mass Spectrometer

NASA Technical Reports Server (NTRS)

Wey, Chowen

1995-01-01

Gas chromatograph/mass spectrometer (GC/MS) used to measure and identify combustion species present in trace concentration. Advanced extractive diagnostic method measures to parts per billion (PPB), as well as differentiates between different types of hydrocarbons. Applicable for petrochemical, waste incinerator, diesel transporation, and electric utility companies in accurately monitoring types of hydrocarbon emissions generated by fuel combustion, in order to meet stricter environmental requirements. Other potential applications include manufacturing processes requiring precise detection of toxic gaseous chemicals, biomedical applications requiring precise identification of accumulative gaseous species, and gas utility operations requiring high-sensitivity leak detection.

Single photon ranging system using two wavelengths laser and analysis of precision

NASA Astrophysics Data System (ADS)

Chen, Yunfei; He, Weiji; Miao, Zhuang; Gu, Guohua; Chen, Qian

2013-09-01

The laser ranging system based on time correlation single photon counting technology and single photon detector has the feature of high precision and low emergent energy etc. In this paper, we established a single photon laser ranging system that use the supercontinuum laser as light source, and two wavelengths (532nm and 830nm) of echo signal as the stop signal. We propose a new method that is capable to improve the single photon ranging system performance. The method is implemented by using two single-photon detectors to receive respectively the two different wavelength signals at the same time. We extracted the firings of the two detectors triggered by the same laser pulse at the same time and then took mean time of the two firings as the combined detection time-of-flight. The detection by two channels using two wavelengths will effectively improve the detection precision and decrease the false alarm probability. Finally, an experimental single photon ranging system was established. Through a lot of experiments, we got the system precision using both single and two wavelengths and verified the effectiveness of the method.

HiCTMap: Detection and analysis of chromosome territory structure and position by high-throughput imaging.

PubMed

Jowhar, Ziad; Gudla, Prabhakar R; Shachar, Sigal; Wangsa, Darawalee; Russ, Jill L; Pegoraro, Gianluca; Ried, Thomas; Raznahan, Armin; Misteli, Tom

2018-06-01

The spatial organization of chromosomes in the nuclear space is an extensively studied field that relies on measurements of structural features and 3D positions of chromosomes with high precision and robustness. However, no tools are currently available to image and analyze chromosome territories in a high-throughput format. Here, we have developed High-throughput Chromosome Territory Mapping (HiCTMap), a method for the robust and rapid analysis of 2D and 3D chromosome territory positioning in mammalian cells. HiCTMap is a high-throughput imaging-based chromosome detection method which enables routine analysis of chromosome structure and nuclear position. Using an optimized FISH staining protocol in a 384-well plate format in conjunction with a bespoke automated image analysis workflow, HiCTMap faithfully detects chromosome territories and their position in 2D and 3D in a large population of cells per experimental condition. We apply this novel technique to visualize chromosomes 18, X, and Y in male and female primary human skin fibroblasts, and show accurate detection of the correct number of chromosomes in the respective genotypes. Given the ability to visualize and quantitatively analyze large numbers of nuclei, we use HiCTMap to measure chromosome territory area and volume with high precision and determine the radial position of chromosome territories using either centroid or equidistant-shell analysis. The HiCTMap protocol is also compatible with RNA FISH as demonstrated by simultaneous labeling of X chromosomes and Xist RNA in female cells. We suggest HiCTMap will be a useful tool for routine precision mapping of chromosome territories in a wide range of cell types and tissues. Published by Elsevier Inc.

High-rate RTK and PPP multi-GNSS positioning for small-scale dynamic displacements monitoring

NASA Astrophysics Data System (ADS)

Paziewski, Jacek; Sieradzki, Rafał; Baryła, Radosław; Wielgosz, Pawel

2017-04-01

The monitoring of dynamic displacements and deformations of engineering structures such as buildings, towers and bridges is of great interest due to several practical and theoretical reasons. The most important is to provide information required for safe maintenance of the constructions. High temporal resolution and precision of GNSS observations predestine this technology to be applied to most demanding application in terms of accuracy, availability and reliability. GNSS technique supported by appropriate processing methodology may meet the specific demands and requirements of ground and structures monitoring. Thus, high-rate multi-GNSS signals may be used as reliable source of information on dynamic displacements of ground and engineering structures, also in real time applications. In this study we present initial results of application of precise relative GNSS positioning for detection of small scale (cm level) high temporal resolution dynamic displacements. Methodology and algorithms applied in self-developed software allowing for relative positioning using high-rate dual-frequency phase and pseudorange GPS+Galileo observations are also given. Additionally, an approach was also made to use the Precise Point Positioning technique to such application. In the experiment were used the observations obtained from high-rate (20 Hz) geodetic receivers. The dynamic displacements were simulated using specially constructed device moving GNSS antenna with dedicated amplitude and frequency. The obtained results indicate on possibility of detection of dynamic displacements of the GNSS antenna even at the level of few millimetres using both relative and Precise Point Positioning techniques after suitable signals processing.

Penning trap mass spectrometry Q-value determinations for highly forbidden β-decays

NASA Astrophysics Data System (ADS)

Sandler, Rachel; Bollen, Georg; Eibach, Martin; Gamage, Nadeesha; Gulyuz, Kerim; Hamaker, Alec; Izzo, Chris; Kandegedara, Rathnayake; Redshaw, Matt; Ringle, Ryan; Valverde, Adrian; Yandow, Isaac; Low Energy Beam Ion Trap Team

2017-09-01

Over the last several decades, extremely sensitive, ultra-low background beta and gamma detection techniques have been developed. These techniques have enabled the observation of very rare processes, such as highly forbidden beta decays e.g. of 113Cd, 50V and 138La. Half-life measurements of highly forbidden beta decays provide a testing ground for theoretical nuclear models, and the comparison of calculated and measured energy spectra could enable a determination of the values of the weak coupling constants. Precision Q-value measurements also allow for systematic tests of the beta-particle detection techniques. We will present the results and current status of Q value determinations for highly forbidden beta decays. The Q values, the mass difference between parent and daughter nuclides, are measured using the high precision Penning trap mass spectrometer LEBIT at the National Superconducting Cyclotron Laboratory.

Automation of ⁹⁹Tc extraction by LOV prior ICP-MS detection: application to environmental samples.

PubMed

Rodríguez, Rogelio; Leal, Luz; Miranda, Silvia; Ferrer, Laura; Avivar, Jessica; García, Ariel; Cerdà, Víctor

2015-02-01

A new, fast, automated and inexpensive sample pre-treatment method for (99)Tc determination by inductively coupled plasma-mass spectrometry (ICP-MS) detection is presented. The miniaturized approach is based on a lab-on-valve (LOV) system, allowing automatic separation and preconcentration of (99)Tc. Selectivity is provided by the solid phase extraction system used (TEVA resin) which retains selectively pertechnetate ion in diluted nitric acid solution. The proposed system has some advantages such as minimization of sample handling, reduction of reagents volume, improvement of intermediate precision and sample throughput, offering a significant decrease of both time and cost per analysis in comparison to other flow techniques and batch methods. The proposed LOV system has been successfully applied to different samples of environmental interest (water and soil) with satisfactory recoveries, between 94% and 98%. The detection limit (LOD) of the developed method is 0.005 ng. The high durability of the resin and its low amount (32 mg), its good intermediate precision (RSD 3.8%) and repeatability (RSD 2%) and its high extraction frequency (up to 5 h(-1)) makes this method an inexpensive, high precision and fast tool for monitoring (99)Tc in environmental samples. Copyright © 2014 Elsevier B.V. All rights reserved.

Automatic small target detection in synthetic infrared images

NASA Astrophysics Data System (ADS)

Yardımcı, Ozan; Ulusoy, Ä.°lkay

2017-05-01

Automatic detection of targets from far distances is a very challenging problem. Background clutter and small target size are the main difficulties which should be solved while reaching a high detection performance as well as a low computational load. The pre-processing, detection and post-processing approaches are very effective on the final results. In this study, first of all, various methods in the literature were evaluated separately for each of these stages using the simulated test scenarios. Then, a full system of detection was constructed among available solutions which resulted in the best performance in terms of detection. However, although a precision rate as 100% was reached, the recall values stayed low around 25-45%. Finally, a post-processing method was proposed which increased the recall value while keeping the precision at 100%. The proposed post-processing method, which is based on local operations, increased the recall value to 65-95% in all test scenarios.

Assisting People with Disabilities in Actively Performing Designated Occupational Activities with Battery-Free Wireless Mice to Control Environmental Stimulation

ERIC Educational Resources Information Center

Shih, Ching-Hsiang

2013-01-01

The latest researches use software technology (OLDP, object location detection programs) to turn a commercial high-technology product, i.e. a battery-free wireless mouse, into a high performance/precise object location detector to detect whether or not an object has been placed in the designated location. The preferred environmental stimulation is…

Optimization of the MINERVA Exoplanet Search Strategy via Simulations

NASA Astrophysics Data System (ADS)

Nava, Chantell; Johnson, Samson; McCrady, Nate; Minerva

2015-01-01

Detection of low-mass exoplanets requires high spectroscopic precision and high observational cadence. MINERVA is a dedicated observatory capable of sub meter-per-second radial velocity precision. As a dedicated observatory, MINERVA can observe with every-clear-night cadence that is essential for low-mass exoplanet detection. However, this cadence complicates the determination of an optimal observing strategy. We simulate MINERVA observations to optimize our observing strategy and maximize exoplanet detections. A dispatch scheduling algorithm provides observations of MINERVA targets every day over a three-year observing campaign. An exoplanet population with a distribution informed by Kepler statistics is assigned to the targets, and radial velocity curves induced by the planets are constructed. We apply a correlated noise model that realistically simulates stellar astrophysical noise sources. The simulated radial velocity data is fed to the MINERVA planet detection code and the expected exoplanet yield is calculated. The full simulation provides a tool to test different strategies for scheduling observations of our targets and optimizing the MINERVA exoplanet search strategy.

PINT, A Modern Software Package for Pulsar Timing

NASA Astrophysics Data System (ADS)

Luo, Jing; Ransom, Scott M.; Demorest, Paul; Ray, Paul S.; Stovall, Kevin; Jenet, Fredrick; Ellis, Justin; van Haasteren, Rutger; Bachetti, Matteo; NANOGrav PINT developer team

2018-01-01

Pulsar timing, first developed decades ago, has provided an extremely wide range of knowledge about our universe. It has been responsible for many important discoveries, such as the discovery of the first exoplanet and the orbital period decay of double neutron star systems. Currently pulsar timing is the leading technique for detecting low frequency (about 10^-9 Hertz) gravitational waves (GW) using an array of pulsars as the detectors. To achieve this goal, high precision pulsar timing data, at about nanoseconds level, is required. Most high precision pulsar timing data are analyzed using the widely adopted software TEMPO/TEMPO2. But for a robust and believable GW detection, it is important to have independent software that can cross-check the result. In this poster we present the new generation pulsar timing software PINT. This package will provide a robust system to cross check high-precision timing results, completely independent of TEMPO and TEMPO2. In addition, PINT is designed to be a package that is easy to extend and modify, through use of flexible code architecture and a modern programming language, Python, with modern technology and libraries.

BEAMing LAMP: single-molecule capture and on-bead isothermal amplification for digital detection of hepatitis C virus in plasma.

PubMed

Chen, Jiyun; Xu, Xiaomin; Huang, Zhimei; Luo, Yuan; Tang, Lijuan; Jiang, Jian-Hui

2018-01-02

A novel dNAD platform (BEAMing LAMP) by combining emulsion micro-reactors, single-molecule magnetic capture and on-bead loop-mediated isothermal amplification has been developed for DNA detection, which enables absolute and high-precision quantification of a target with a detection limit of 300 copies.

[Determination of vitamins D2, vitamin D3 in cosmetics by high performance liquid chromatography].

PubMed

Zhu, Ying; Yang, Yan-Wei; Wang, Xin

2005-09-01

A high performance liquid chromatography method was used to detect vitamins D2 and vitamin D3, which is useful to know the use of vitamins D2 and vitamin D3 in cosmetics, prohibit the influx of cosmetics containing vitamins D2 and vitamin D3 to cosmetic market, safeguard the health of consumers. A high performance liquid chromatography method was established for determination of vitamins D2 and vitamin D3 in cosmetics. The separation condition was optimized by trying different type of columns and mobile phases. The experiment goes on a Alltima C18 column (250 mm x 4.6 mm I. D., 5 microm)using methanol-acetonitrile (90: 10) as mobile phase at a flow rate of 1.0 ml/min, with the column temperature 25 degrees C and detection wave 265nm. The liner range is from 0.5 mg/L to 100 mg/L with good relationship. The detection limit of vitamin D2 is 0. 12 mg/L, the precision is less than 3.8% and recovery varies from 94.2% to 101.4%, while the detection limit of vitamin D3 is 0.06 mg/L, the precision is less than 3.5% and recovery varies from 91.6% to 97.2%. The method is simple, precise and accurate, which is suitable for the determination of vitamins D2 and vitamin D3 in cosmetics.

Precision Landing and Hazard Avoidance Doman

NASA Technical Reports Server (NTRS)

Robertson, Edward A.; Carson, John M., III

2016-01-01

The Precision Landing and Hazard Avoidance (PL&HA) domain addresses the development, integration, testing, and spaceflight infusion of sensing, processing, and GN&C functions critical to the success and safety of future human and robotic exploration missions. PL&HA sensors also have applications to other mission events, such as rendezvous and docking. Autonomous PL&HA builds upon the core GN&C capabilities developed to enable soft, controlled landings on the Moon, Mars, and other solar system bodies. Through the addition of a Terrain Relative Navigation (TRN) function, precision landing within tens of meters of a map-based target is possible. The addition of a 3-D terrain mapping lidar sensor improves the probability of a safe landing via autonomous, real-time Hazard Detection and Avoidance (HDA). PL&HA significantly improves the probability of mission success and enhances access to sites of scientific interest located in challenging terrain. PL&HA can also utilize external navigation aids, such as navigation satellites and surface beacons. Advanced Lidar Sensors High precision ranging, velocimetry, and 3-D terrain mapping Terrain Relative Navigation (TRN) TRN compares onboard reconnaissance data with real-time terrain imaging data to update the S/C position estimate Hazard Detection and Avoidance (HDA) Generates a high-resolution, 3-D terrain map in real-time during the approach trajectory to identify safe landing targets Inertial Navigation During Terminal Descent High precision surface relative sensors enable accurate inertial navigation during terminal descent and a tightly controlled touchdown within meters of the selected safe landing target.

Moving Object Detection Using Scanning Camera on a High-Precision Intelligent Holder

PubMed Central

Chen, Shuoyang; Xu, Tingfa; Li, Daqun; Zhang, Jizhou; Jiang, Shenwang

2016-01-01

During the process of moving object detection in an intelligent visual surveillance system, a scenario with complex background is sure to appear. The traditional methods, such as “frame difference” and “optical flow”, may not able to deal with the problem very well. In such scenarios, we use a modified algorithm to do the background modeling work. In this paper, we use edge detection to get an edge difference image just to enhance the ability of resistance illumination variation. Then we use a “multi-block temporal-analyzing LBP (Local Binary Pattern)” algorithm to do the segmentation. In the end, a connected component is used to locate the object. We also produce a hardware platform, the core of which consists of the DSP (Digital Signal Processor) and FPGA (Field Programmable Gate Array) platforms and the high-precision intelligent holder. PMID:27775671

Study on the Automatic Detection Method and System of Multifunctional Hydrocephalus Shunt

NASA Astrophysics Data System (ADS)

Sun, Xuan; Wang, Guangzhen; Dong, Quancheng; Li, Yuzhong

2017-07-01

Aiming to the difficulty of micro pressure detection and the difficulty of micro flow control in the testing process of hydrocephalus shunt, the principle of the shunt performance detection was analyzed.In this study, the author analyzed the principle of several items of shunt performance detection,and used advanced micro pressure sensor and micro flow peristaltic pump to overcome the micro pressure detection and micro flow control technology.At the same time,This study also puted many common experimental projects integrated, and successfully developed the automatic detection system for a shunt performance detection function, to achieve a test with high precision, high efficiency and automation.

Detecting transit signatures of exoplanetary rings using SOAP3.0

NASA Astrophysics Data System (ADS)

Akinsanmi, B.; Oshagh, M.; Santos, N. C.; Barros, S. C. C.

2018-01-01

Context. It is theoretically possible for rings to have formed around extrasolar planets in a similar way to that in which they formed around the giant planets in our solar system. However, no such rings have been detected to date. Aims: We aim to test the possibility of detecting rings around exoplanets by investigating the photometric and spectroscopic ring signatures in high-precision transit signals. Methods: The photometric and spectroscopic transit signals of a ringed planet is expected to show deviations from that of a spherical planet. We used these deviations to quantify the detectability of rings. We present SOAP3.0 which is a numerical tool to simulate ringed planet transits and measure ring detectability based on amplitudes of the residuals between the ringed planet signal and best fit ringless model. Results: We find that it is possible to detect the photometric and spectroscopic signature of near edge-on rings especially around planets with high impact parameter. Time resolution ≤7 min is required for the photometric detection, while 15 min is sufficient for the spectroscopic detection. We also show that future instruments like CHEOPS and ESPRESSO, with precisions that allow ring signatures to be well above their noise-level, present good prospects for detecting rings.

Video-rate or high-precision: a flexible range imaging camera

NASA Astrophysics Data System (ADS)

Dorrington, Adrian A.; Cree, Michael J.; Carnegie, Dale A.; Payne, Andrew D.; Conroy, Richard M.; Godbaz, John P.; Jongenelen, Adrian P. P.

2008-02-01

A range imaging camera produces an output similar to a digital photograph, but every pixel in the image contains distance information as well as intensity. This is useful for measuring the shape, size and location of objects in a scene, hence is well suited to certain machine vision applications. Previously we demonstrated a heterodyne range imaging system operating in a relatively high resolution (512-by-512) pixels and high precision (0.4 mm best case) configuration, but with a slow measurement rate (one every 10 s). Although this high precision range imaging is useful for some applications, the low acquisition speed is limiting in many situations. The system's frame rate and length of acquisition is fully configurable in software, which means the measurement rate can be increased by compromising precision and image resolution. In this paper we demonstrate the flexibility of our range imaging system by showing examples of high precision ranging at slow acquisition speeds and video-rate ranging with reduced ranging precision and image resolution. We also show that the heterodyne approach and the use of more than four samples per beat cycle provides better linearity than the traditional homodyne quadrature detection approach. Finally, we comment on practical issues of frame rate and beat signal frequency selection.

Development of the fast and efficient gamma detector using Cherenkov light for TOF-PET

NASA Astrophysics Data System (ADS)

Canot, C.; Alokhina, M.; Abbon, P.; Bard, J. P.; Tauzin, G.; Yvon, D.; Sharyy, V.

2017-12-01

In this paper we present two configurations of innovative gamma detectors using Cherenkov light for time-of-flight—Positron Emission Tomography (PET). The first uses heavy crystals as a Cherenkov radiator to develop a demonstrator for a whole body PET scanner with high detection efficiency. We demonstrated a 30% detection efficiency and a 180 ps (FWHM) time resolution, mainly limited by the time transit spread of the photomultiplier. The second configuration uses an innovative liquid, the TriMethyl Bismuth, to develop a high precision brain-scanning PET device with time-of-flight capability. According to Geant4 simulation, we expect to reach a precision of 150 ps (FWHM) and an efficiency of about 25%.

Dendrochemical patterns of calcium, zinc, and potassium related to internal factors detected by energy dispersive X-ray fluorescence (EDXRF)

Treesearch

Kevin T. Smith; Jean Christophe Balouet; Walter C. Shortle; Michel Chalot; François Beaujard; Hakan Grudd; Don A. Vroblesky; Joel G. Burken

2014-01-01

Energy dispersive X-ray fluorescence (EDXRF) provides highly sensitive and precise spatial resolution of cation content in individual annual growth rings in trees. The sensitivity and precision have prompted successful applications to forensic dendrochemistry and the timing of environmental releases of contaminants. These applications have highlighted the need to...

Dent detection method by high gradation photometric stereo

NASA Astrophysics Data System (ADS)

Hasebe, Akihisa; Kato, Kunihito; Tanahashi, Hideki; Kubota, Naoki

2017-03-01

This paper describes an automatic detection method for small dents on a metal plate. We adopted the photometric stereo as a three-dimensional measurement method, which has advantages in terms of low cost and short measurement time. In addition, a high precision measurement system was realized by using an 18bit camera. Furthermore, the small dent on the surface of the metal plate is detected by the inner product of the measured normal vectors using photometric stereo. Finally, the effectiveness of our method was confirmed by detection experiments.

Assessing the detectability of antioxidants in two-dimensional high-performance liquid chromatography.

PubMed

Bassanese, Danielle N; Conlan, Xavier A; Barnett, Neil W; Stevenson, Paul G

2015-05-01

This paper explores the analytical figures of merit of two-dimensional high-performance liquid chromatography for the separation of antioxidant standards. The cumulative two-dimensional high-performance liquid chromatography peak area was calculated for 11 antioxidants by two different methods--the areas reported by the control software and by fitting the data with a Gaussian model; these methods were evaluated for precision and sensitivity. Both methods demonstrated excellent precision in regards to retention time in the second dimension (%RSD below 1.16%) and cumulative second dimension peak area (%RSD below 3.73% from the instrument software and 5.87% for the Gaussian method). Combining areas reported by the high-performance liquid chromatographic control software displayed superior limits of detection, in the order of 1 × 10(-6) M, almost an order of magnitude lower than the Gaussian method for some analytes. The introduction of the countergradient eliminated the strong solvent mismatch between dimensions, leading to a much improved peak shape and better detection limits for quantification. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Performance evaluation of the HepB Typer-Entecavir kit for detection of entecavir resistance mutations in chronic hepatitis B.

PubMed

Ahn, Sang Hoon; Chun, Ji-Yong; Shin, Soo-Kyung; Park, Jun Yong; Yoo, Wangdon; Hong, Sun Pyo; Kim, Soo-Ok; Han, Kwang-Hyub

2013-12-01

Molecular diagnostic methods have enabled the rapid diagnosis of drug-resistant mutations in hepatitis B virus (HBV) and have reduced both unnecessary therapeutic interventions and medical costs. In this study we evaluated the analytical and clinical performances of the HepB Typer-Entecavir kit (GeneMatrix, Korea) in detecting entecavir-resistance-associated mutations. The HepB Typer-Entecavir kit was evaluated for its limit of detection, interference, cross-reactivity, and precision using HBV reference standards made by diluting high-titer viral stocks in HBV-negative human serum. The performance of the HepB Typer-Entecavir kit for detecting mutations related to entecavir resistance was compared with direct sequencing for 396 clinical samples from 108 patients. Using the reference standards, the detection limit of the HepB Typer-Entecavir kit was found to be as low as 500 copies/mL. No cross-reactivity was observed, and elevated levels of various interfering substances did not adversely affect its analytical performance. The precision test conducted by repetitive analysis of 2,400 replicates with reference standards at various concentrations showed 99.9% agreement (2398/2400). The overall concordance rate between the HepB Typer-Entecavir kit and direct sequencing assays in 396 clinical samples was 99.5%. The HepB Typer-Entecavir kit showed high reliability and precision, and comparable sensitivity and specificity for detecting mutant virus populations in reference and clinical samples in comparison with direct sequencing. Therefore, this assay would be clinically useful in the diagnosis of entecavir-resistance-associated mutations in chronic hepatitis B.

[A quick algorithm of dynamic spectrum photoelectric pulse wave detection based on LabVIEW].

PubMed

Lin, Ling; Li, Na; Li, Gang

2010-02-01

Dynamic spectrum (DS) detection is attractive among the numerous noninvasive blood component detection methods because of the elimination of the main interference of the individual discrepancy and measure conditions. DS is a kind of spectrum extracted from the photoelectric pulse wave and closely relative to the artery blood. It can be used in a noninvasive blood component concentration examination. The key issues in DS detection are high detection precision and high operation speed. The precision of measure can be advanced by making use of over-sampling and lock-in amplifying on the pick-up of photoelectric pulse wave in DS detection. In the present paper, the theory expression formula of the over-sampling and lock-in amplifying method was deduced firstly. Then in order to overcome the problems of great data and excessive operation brought on by this technology, a quick algorithm based on LabVIEW and a method of using external C code applied in the pick-up of photoelectric pulse wave were presented. Experimental verification was conducted in the environment of LabVIEW. The results show that by the method pres ented, the speed of operation was promoted rapidly and the data memory was reduced largely.

Precisely Controlled Ultrathin Conjugated Polymer Films for Large Area Transparent Transistors and Highly Sensitive Chemical Sensors.

PubMed

Khim, Dongyoon; Ryu, Gi-Seong; Park, Won-Tae; Kim, Hyunchul; Lee, Myungwon; Noh, Yong-Young

2016-04-13

A uniform ultrathin polymer film is deposited over a large area with molecularlevel precision by the simple wire-wound bar-coating method. The bar-coated ultrathin films not only exhibit high transparency of up to 90% in the visible wavelength range but also high charge carrier mobility with a high degree of percolation through the uniformly covered polymer nanofibrils. They are capable of realizing highly sensitive multigas sensors and represent the first successful report of ethylene detection using a sensor based on organic field-effect transistors. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Precision requirements and innovative manufacturing for ultrahigh precision laser interferometry of gravitational-wave astronomy

NASA Astrophysics Data System (ADS)

Ni, Wei-Tou; Han, Sen; Jin, Tao

2016-11-01

With the LIGO announcement of the first direct detection of gravitational waves (GWs), the GW Astronomy was formally ushered into our age. After one-hundred years of theoretical investigation and fifty years of experimental endeavor, this is a historical landmark not just for physics and astronomy, but also for industry and manufacturing. The challenge and opportunity for industry is precision and innovative manufacturing in large size - production of large and homogeneous optical components, optical diagnosis of large components, high reflectance dielectric coating on large mirrors, manufacturing of components for ultrahigh vacuum of large volume, manufacturing of high attenuating vibration isolation system, production of high-power high-stability single-frequency lasers, production of high-resolution positioning systems etc. In this talk, we address the requirements and methods to satisfy these requirements. Optical diagnosis of large optical components requires large phase-shifting interferometer; the 1.06 μm Phase Shifting Interferometer for testing LIGO optics and the recently built 24" phase-shifting Interferometer in Chengdu, China are examples. High quality mirrors are crucial for laser interferometric GW detection, so as for ring laser gyroscope, high precision laser stabilization via optical cavities, quantum optomechanics, cavity quantum electrodynamics and vacuum birefringence measurement. There are stringent requirements on the substrate materials and coating methods. For cryogenic GW interferometer, appropriate coating on sapphire or silicon are required for good thermal and homogeneity properties. Large ultrahigh vacuum components and high attenuating vibration system together with an efficient metrology system are required and will be addressed. For space interferometry, drag-free technology and weak-light manipulation technology are must. Drag-free technology is well-developed. Weak-light phase locking is demonstrated in the laboratories while weak-light manipulation technology still needs developments.

A microfluidic system with integrated molecular imprinting polymer films for surface plasmon resonance detection

NASA Astrophysics Data System (ADS)

Huang, Shih-Chiang; Lee, Gwo-Bin; Chien, Fan-Ching; Chen, Shean-Jen; Chen, Wen-Janq; Yang, Ming-Chang

2006-07-01

This paper presents a novel microfluidic system with integrated molecular imprinting polymer (MIP) films designed for surface plasmon resonance (SPR) biosensing of multiple nanoscale biomolecules. The innovative microfluidic chip uses pneumatic microvalves and micropumps to transport a precise amount of the biosample through multiple microchannels to sensing regions containing the locally spin-coated MIP films. The signals of SPR biosensing are basically proportional to the number of molecules adsorbed on the MIP films. Hence, a precise control of flow rates inside microchannels is important to determine the adsorption amount of the molecules in the SPR/MIP chips. The integration of micropumps and microvalves can automate the sample introduction process and precisely control the amount of the sample injection to the microfluidic system. The proposed biochip enables the label-free biosensing of biomolecules in an automatic format, and provides a highly sensitive, highly specific and high-throughput detection performance. Three samples, i.e. progesterone, cholesterol and testosterone, are successfully detected using the developed system. The experimental results show that the proposed SPR/MIP microfluidic chip provides a comparable sensitivity to that of large-scale SPR techniques, but with reduced sample consumption and an automatic format. As such, the developed biochip has significant potential for a wide variety of nanoscale biosensing applications. The preliminary results of the current paper were presented at Transducers 2005, Seoul, Korea, 5-9 June 2005.

Ready to clone: CNV detection and breakpoint fine-mapping in breast and ovarian cancer susceptibility genes by high-resolution array CGH.

PubMed

Hackmann, Karl; Kuhlee, Franziska; Betcheva-Krajcir, Elitza; Kahlert, Anne-Karin; Mackenroth, Luisa; Klink, Barbara; Di Donato, Nataliya; Tzschach, Andreas; Kast, Karin; Wimberger, Pauline; Schrock, Evelin; Rump, Andreas

2016-10-01

Detection of predisposing copy number variants (CNV) in 330 families affected with hereditary breast and ovarian cancer (HBOC). In order to complement mutation detection with Illumina's TruSight Cancer panel, we designed a customized high-resolution 8 × 60k array for CGH (aCGH) that covers all 94 genes from the panel. Copy number variants with immediate clinical relevance were detected in 12 families (3.6%). Besides 3 known CNVs in CHEK2, RAD51C, and BRCA1, we identified 3 novel pathogenic CNVs in BRCA1 (deletion of exons 4-13, deletion of exons 12-18) and ATM (deletion exons 57-63) plus an intragenic duplication of BRCA2 (exons 3-11) and an intronic BRCA1 variant with unknown pathogenicity. The precision of high-resolution aCGH enabled straight forward breakpoint amplification of a BRCA1 deletion which subsequently allowed for fast and economic CNV verification in family members of the index patient. Furthermore, we used our aCGH data to validate an algorithm that was able to detect all identified copy number changes from next-generation sequencing (NGS) data. Copy number detection is a mandatory analysis in HBOC families at least if no predisposing mutations were found by sequencing. Currently, high-resolution array CGH is our first choice of method of analysis due to unmatched detection precision. Although it seems possible to detect CNV from sequencing data, there currently is no satisfying tool to do so in a routine diagnostic setting.

Study on the special vision sensor for detecting position error in robot precise TIG welding of some key part of rocket engine

NASA Astrophysics Data System (ADS)

Zhang, Wenzeng; Chen, Nian; Wang, Bin; Cao, Yipeng

2005-01-01

Rocket engine is a hard-core part of aerospace transportation and thrusting system, whose research and development is very important in national defense, aviation and aerospace. A novel vision sensor is developed, which can be used for error detecting in arc length control and seam tracking in precise pulse TIG welding of the extending part of the rocket engine jet tube. The vision sensor has many advantages, such as imaging with high quality, compactness and multiple functions. The optics design, mechanism design and circuit design of the vision sensor have been described in detail. Utilizing the mirror imaging of Tungsten electrode in the weld pool, a novel method is proposed to detect the arc length and seam tracking error of Tungsten electrode to the center line of joint seam from a single weld image. A calculating model of the method is proposed according to the relation of the Tungsten electrode, weld pool, the mirror of Tungsten electrode in weld pool and joint seam. The new methodologies are given to detect the arc length and seam tracking error. Through analyzing the results of the experiments, a system error modifying method based on a linear function is developed to improve the detecting precise of arc length and seam tracking error. Experimental results show that the final precision of the system reaches 0.1 mm in detecting the arc length and the seam tracking error of Tungsten electrode to the center line of joint seam.

Feasibility of precise navigation in high and low latitude regions under scintillation conditions

NASA Astrophysics Data System (ADS)

Juan, José Miguel; Sanz, Jaume; González-Casado, Guillermo; Rovira-Garcia, Adrià; Camps, Adriano; Riba, Jaume; Barbosa, José; Blanch, Estefania; Altadill, David; Orus, Raul

2018-02-01

Scintillation is one of the most challenging problems in Global Navigation Satellite Systems (GNSS) navigation. This phenomenon appears when the radio signal passes through ionospheric irregularities. These irregularities represent rapid changes on the refraction index and, depending on their size, they can produce also diffractive effects affecting the signal amplitude and, eventually producing cycle slips. In this work, we show that the scintillation effects on the GNSS signal are quite different in low and high latitudes. For low latitude receivers, the main effects, from the point of view of precise navigation, are the increase of the carrier phase noise (measured by σϕ) and the fade on the signal intensity (measured by S4) that can produce cycle slips in the GNSS signal. With several examples, we show that the detection of these cycle slips is the most challenging problem for precise navigation, in such a way that, if these cycle slips are detected, precise navigation can be achieved in these regions under scintillation conditions. For high-latitude receivers the situation differs. In this region the size of the irregularities is typically larger than the Fresnel length, so the main effects are related with the fast change on the refractive index associated to the fast movement of the irregularities (which can reach velocities up to several km/s). Consequently, the main effect on the GNSS signals is a fast fluctuation of the carrier phase (large σϕ), but with a moderate fade in the amplitude (moderate S4). Therefore, as shown through several examples, fluctuations at high-latitude usually do not produce cycle slips, being the effect quite limited on the ionosphere-free combination and, in general, precise navigation can be achieved also during strong scintillation conditions.

Parameter Estimation with Entangled Photons Produced by Parametric Down-Conversion

NASA Technical Reports Server (NTRS)

Cable, Hugo; Durkin, Gabriel A.

2010-01-01

We explore the advantages offered by twin light beams produced in parametric down-conversion for precision measurement. The symmetry of these bipartite quantum states, even under losses, suggests that monitoring correlations between the divergent beams permits a high-precision inference of any symmetry-breaking effect, e.g., fiber birefringence. We show that the quantity of entanglement is not the key feature for such an instrument. In a lossless setting, scaling of precision at the ultimate "Heisenberg" limit is possible with photon counting alone. Even as photon losses approach 100% the precision is shot-noise limited, and we identify the crossover point between quantum and classical precision as a function of detected flux. The predicted hypersensitivity is demonstrated with a Bayesian simulation.

Parameter estimation with entangled photons produced by parametric down-conversion.

PubMed

Cable, Hugo; Durkin, Gabriel A

2010-07-02

We explore the advantages offered by twin light beams produced in parametric down-conversion for precision measurement. The symmetry of these bipartite quantum states, even under losses, suggests that monitoring correlations between the divergent beams permits a high-precision inference of any symmetry-breaking effect, e.g., fiber birefringence. We show that the quantity of entanglement is not the key feature for such an instrument. In a lossless setting, scaling of precision at the ultimate "Heisenberg" limit is possible with photon counting alone. Even as photon losses approach 100% the precision is shot-noise limited, and we identify the crossover point between quantum and classical precision as a function of detected flux. The predicted hypersensitivity is demonstrated with a Bayesian simulation.

Loss of heterozygosity assay for molecular detection of cancer using energy-transfer primers and capillary array electrophoresis.

PubMed

Medintz, I L; Lee, C C; Wong, W W; Pirkola, K; Sidransky, D; Mathies, R A

2000-08-01

Microsatellite DNA loci are useful markers for the detection of loss of heterozygosity (LOH) and microsatellite instability (MI) associated with primary cancers. To carry out large-scale studies of LOH and MI in cancer progression, high-throughput instrumentation and assays with high accuracy and sensitivity need to be validated. DNA was extracted from 26 renal tumor and paired lymphocyte samples and amplified with two-color energy-transfer (ET) fluorescent primers specific for loci associated with cancer-induced chromosomal changes. PCR amplicons were separated on the MegaBACE-1000 96 capillary array electrophoresis (CAE) instrument and analyzed with MegaBACE Genetic Profiler v.1.0 software. Ninety-six separations were achieved in parallel in 75 minutes. Loss of heterozygosity was easily detected in tumor samples as was the gain/loss of microsatellite core repeats. Allelic ratios were determined with a precision of +/- 10% or better. Prior analysis of these samples with slab gel electrophoresis and radioisotope labeling had not detected these changes with as much sensitivity or precision. This study establishes the validity of this assay and the MegaBACE instrument for large-scale, high-throughput studies of the molecular genetic changes associated with cancer.

Cumulative detection probabilities and range accuracy of a pulsed Geiger-mode avalanche photodiode laser ranging system

NASA Astrophysics Data System (ADS)

Luo, Hanjun; Ouyang, Zhengbiao; Liu, Qiang; Chen, Zhiliang; Lu, Hualan

2017-10-01

Cumulative pulses detection with appropriate cumulative pulses number and threshold has the ability to improve the detection performance of the pulsed laser ranging system with GM-APD. In this paper, based on Poisson statistics and multi-pulses cumulative process, the cumulative detection probabilities and their influence factors are investigated. With the normalized probability distribution of each time bin, the theoretical model of the range accuracy and precision is established, and the factors limiting the range accuracy and precision are discussed. The results show that the cumulative pulses detection can produce higher target detection probability and lower false alarm probability. However, for a heavy noise level and extremely weak echo intensity, the false alarm suppression performance of the cumulative pulses detection deteriorates quickly. The range accuracy and precision is another important parameter evaluating the detection performance, the echo intensity and pulse width are main influence factors on the range accuracy and precision, and higher range accuracy and precision is acquired with stronger echo intensity and narrower echo pulse width, for 5-ns echo pulse width, when the echo intensity is larger than 10, the range accuracy and precision lower than 7.5 cm can be achieved.

Bringing mirrors to rest: grating concepts for ultra-precise interferometry

NASA Astrophysics Data System (ADS)

Kroker, Stefanie; Kley, Ernst-Bernhard; Tünnermann, Andreas

2015-02-01

Experiments in the field of high precision metrology such as the detection of gravitational waves are crucially limited by the thermal fluctuations of the optical components. In this contribution we present the current state of knowledge of high contrast gratings (HCGs) as low-noise elements for gravitational wave interferometers. We discuss how the properties of HCGs can be tailored such that beside highly reflective mirrors also diffractive beam splitters can be realized. Further, we show the impact of such gratings on the sensitivity of future gravitational wave detectors which can pave the way for the new field of gravitational wave astronomy.

Determination of dasatinib in the tablet dosage form by ultra high performance liquid chromatography, capillary zone electrophoresis, and sequential injection analysis.

PubMed

Gonzalez, Aroa Garcia; Taraba, Lukáš; Hraníček, Jakub; Kozlík, Petr; Coufal, Pavel

2017-01-01

Dasatinib is a novel oral prescription drug proposed for treating adult patients with chronic myeloid leukemia. Three analytical methods, namely ultra high performance liquid chromatography, capillary zone electrophoresis, and sequential injection analysis, were developed, validated, and compared for determination of the drug in the tablet dosage form. The total analysis time of optimized ultra high performance liquid chromatography and capillary zone electrophoresis methods was 2.0 and 2.2 min, respectively. Direct ultraviolet detection with detection wavelength of 322 nm was employed in both cases. The optimized sequential injection analysis method was based on spectrophotometric detection of dasatinib after a simple colorimetric reaction with folin ciocalteau reagent forming a blue-colored complex with an absorbance maximum at 745 nm. The total analysis time was 2.5 min. The ultra high performance liquid chromatography method provided the lowest detection and quantitation limits and the most precise and accurate results. All three newly developed methods were demonstrated to be specific, linear, sensitive, precise, and accurate, providing results satisfactorily meeting the requirements of the pharmaceutical industry, and can be employed for the routine determination of the active pharmaceutical ingredient in the tablet dosage form. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Evaluation on the detection limit of blood hemoglobin using photolepthysmography based on path-length optimization

NASA Astrophysics Data System (ADS)

Sun, Di; Guo, Chao; Zhang, Ziyang; Han, Tongshuai; Liu, Jin

2016-10-01

The blood hemoglobin concentration's (BHC) measurement using Photoplethysmography (PPG), which gets blood absorption to near infrared light from the instantaneous pulse of transmitted light intensity, has not been applied to the clinical use due to the non-enough precision. The main challenge might be caused of the non-enough stable pulse signal when it's very weak and it often varies in different human bodies or in the same body with different physiological states. We evaluated the detection limit of BHC using PPG as the measurement precision level, which can be considered as a best precision result because we got the relative stable subject's pulse signals recorded by using a spectrometer with high signal-to-noise ratio (SNR) level, which is about 30000:1 in short term. Moreover, we optimized the used pathlength using the theory based on optimum pathlength to get a better sensitivity to the absorption variation in blood. The best detection limit was evaluated as about 1 g/L for BHC, and the best SNR of pulse for in vivo measurement was about 2000:1 at 1130 and 1250 nm. Meanwhile, we conclude that the SNR of pulse signal should be better than 400:1 when the required detection limit is set to 5 g/L. Our result would be a good reference to the BHC measurement to get a desired BHC measurement precision of real application.

Urban forest topographical mapping using UAV LIDAR

NASA Astrophysics Data System (ADS)

Putut Ash Shidiq, Iqbal; Wibowo, Adi; Kusratmoko, Eko; Indratmoko, Satria; Ardhianto, Ronni; Prasetyo Nugroho, Budi

2017-12-01

Topographical data is highly needed by many parties, such as government institution, mining companies and agricultural sectors. It is not just about the precision, the acquisition time and data processing are also carefully considered. In relation with forest management, a high accuracy topographic map is necessary for planning, close monitoring and evaluating forest changes. One of the solution to quickly and precisely mapped topography is using remote sensing system. In this study, we test high-resolution data using Light Detection and Ranging (LiDAR) collected from unmanned aerial vehicles (UAV) to map topography and differentiate vegetation classes based on height in urban forest area of University of Indonesia (UI). The semi-automatic and manual classifications were applied to divide point clouds into two main classes, namely ground and vegetation. There were 15,806,380 point clouds obtained during the post-process, in which 2.39% of it were detected as ground.

A light and faster regional convolutional neural network for object detection in optical remote sensing images

NASA Astrophysics Data System (ADS)

Ding, Peng; Zhang, Ye; Deng, Wei-Jian; Jia, Ping; Kuijper, Arjan

2018-07-01

Detection of objects from satellite optical remote sensing images is very important for many commercial and governmental applications. With the development of deep convolutional neural networks (deep CNNs), the field of object detection has seen tremendous advances. Currently, objects in satellite remote sensing images can be detected using deep CNNs. In general, optical remote sensing images contain many dense and small objects, and the use of the original Faster Regional CNN framework does not yield a suitably high precision. Therefore, after careful analysis we adopt dense convoluted networks, a multi-scale representation and various combinations of improvement schemes to enhance the structure of the base VGG16-Net for improving the precision. We propose an approach to reduce the test-time (detection time) and memory requirements. To validate the effectiveness of our approach, we perform experiments using satellite remote sensing image datasets of aircraft and automobiles. The results show that the improved network structure can detect objects in satellite optical remote sensing images more accurately and efficiently.

Determination of MDMA, MDEA and MDA in urine by high performance liquid chromatography with fluorescence detection.

PubMed

da Costa, José Luiz; da Matta Chasin, Alice Aparecida

2004-11-05

This paper describes the development and validation of analytical methodology for the determination of the use of MDMA, MDEA and MDA in urine. After a simple liquid extraction, the analyses were carried out on a high performance liquid chromatography (HPLC) in an octadecyl column, with fluorescence detection. The mobile phase using a sodium dodecyl sulfate ion-pairing reagent allows good separation and efficiency. The method showed good linearity and precision. Recovery was between 85 and 102% and detection limits were 10, 15 and 20 ng/ml for MDA, MDMA and MDEA, respectively. No interfering substances were detected with fluorescence detection.

Multi-resolution Gabor wavelet feature extraction for needle detection in 3D ultrasound

NASA Astrophysics Data System (ADS)

Pourtaherian, Arash; Zinger, Svitlana; Mihajlovic, Nenad; de With, Peter H. N.; Huang, Jinfeng; Ng, Gary C.; Korsten, Hendrikus H. M.

2015-12-01

Ultrasound imaging is employed for needle guidance in various minimally invasive procedures such as biopsy guidance, regional anesthesia and brachytherapy. Unfortunately, a needle guidance using 2D ultrasound is very challenging, due to a poor needle visibility and a limited field of view. Nowadays, 3D ultrasound systems are available and more widely used. Consequently, with an appropriate 3D image-based needle detection technique, needle guidance and interventions may significantly be improved and simplified. In this paper, we present a multi-resolution Gabor transformation for an automated and reliable extraction of the needle-like structures in a 3D ultrasound volume. We study and identify the best combination of the Gabor wavelet frequencies. High precision in detecting the needle voxels leads to a robust and accurate localization of the needle for the intervention support. Evaluation in several ex-vivo cases shows that the multi-resolution analysis significantly improves the precision of the needle voxel detection from 0.23 to 0.32 at a high recall rate of 0.75 (gain 40%), where a better robustness and confidence were confirmed in the practical experiments.

[Assessment of lymph node metastasis in gastric cancer: status quo, recent advances and new perspectives].

PubMed

Tu, Min; Zhu, Zhen-shu; Shi, Lin-sen; Jiang, Xi-qun; Wang, Hao; Guan, Wen-xian

2012-02-01

The precondition of accurate gastric cancer surgery is precise assessment of lymph node metastasis. To date, no imaging modality achieves both high sensitivity and high specificity in detecting lymph node metastasis in gastric cancer. Intraoperative sentinel node tracing and biopsy are the most popular method to identify the localization of tumor cell, but is limited to early gastric cancer. Nano-composite materials, designed for tumor imaging and tracing, show us a newly emerging domain for tumor detection in gastric cancer. The function of these nano-composite materials to detect lymph node metastasis in gastric cancer relies on the effective backflow of lymph system. However, the lymph vessels can be obstructed by tumor cells in advanced gastric cancer, which may restrain the application of these nanoparticles. Therefore, more methods to detect lymph node metastasis in gastric cancer should be explored. This review summarizes the characteristic of the targeted nanosphere. Based on the reported studies, a novel idea is conceived that targeted multifunctional nanosphere may be a potential method to achieve precise assessment of lymph node metastasis in gastric cancer.

Measurement device for high-precision spectral transmittance of solar blind filter

NASA Astrophysics Data System (ADS)

Wang, Yan; Qian, Yunsheng; Lv, Yang; Feng, Cheng; Liu, Jian

2017-02-01

In order to measure spectral transmittance of solar-blind filter ranging from ultraviolet to visible light accurately, a high-precision filter transmittance measuring system based on the ultraviolet photomultiplier is developed. The calibration method is mainly used to measure transmittance in this system, which mainly consists of an ultraviolet photomultiplier as core of the system and a lock-in amplifier combined with an optical modulator as the aided measurement for the system. The ultraviolet photomultiplier can amplify the current signal through the filter and have the characteristics of low dark current and high luminance gain. The optical modulator and the lock-in amplifier can obtain the signal from the photomultiplier and inhibit dark noise and spurious signal effectively. Through these two parts, the low light passing through the filters can be detected and we can calculate the transmittance by the optical power detected. Based on the proposed system, the limit detection of the transmittance can reach 10-12, while the result of the conventional approach is merely 10-6. Therefore, the system can make an effective assessment of solar blind ultraviolet filters.

Image overlay solution based on threshold detection for a compact near infrared fluorescence goggle system

NASA Astrophysics Data System (ADS)

Gao, Shengkui; Mondal, Suman B.; Zhu, Nan; Liang, RongGuang; Achilefu, Samuel; Gruev, Viktor

2015-01-01

Near infrared (NIR) fluorescence imaging has shown great potential for various clinical procedures, including intraoperative image guidance. However, existing NIR fluorescence imaging systems either have a large footprint or are handheld, which limits their usage in intraoperative applications. We present a compact NIR fluorescence imaging system (NFIS) with an image overlay solution based on threshold detection, which can be easily integrated with a goggle display system for intraoperative guidance. The proposed NFIS achieves compactness, light weight, hands-free operation, high-precision superimposition, and a real-time frame rate. In addition, the miniature and ultra-lightweight light-emitting diode tracking pod is easy to incorporate with NIR fluorescence imaging. Based on experimental evaluation, the proposed NFIS solution has a lower detection limit of 25 nM of indocyanine green at 27 fps and realizes a highly precise image overlay of NIR and visible images of mice in vivo. The overlay error is limited within a 2-mm scale at a 65-cm working distance, which is highly reliable for clinical study and surgical use.

Development and test of photon counting lidar

NASA Astrophysics Data System (ADS)

Wang, Chun-hui; Wang, Ao-you; Tao, Yu-liang; Li, Xu; Peng, Huan; Meng, Pei-bei

2018-02-01

In order to satisfy the application requirements of spaceborne three dimensional imaging lidar , a prototype of nonscanning multi-channel lidar based on receiver field of view segmentation was designed and developed. High repetition frequency micro-pulse lasers, optics fiber array and Geiger-mode APD, combination with time-correlated single photon counting technology, were adopted to achieve multi-channel detection. Ranging experiments were carried out outdoors. In low echo photon condition, target photon counting showed time correlated and noise photon counting were random. Detection probability and range precision versus threshold were described and range precision increased from 0.44 to 0.11 when threshold increased from 4 to 8.

Performance evaluation of the HepB Typer-Entecavir kit for detection of entecavir resistance mutations in chronic hepatitis B

PubMed Central

Ahn, Sang Hoon; Chun, Ji-Yong; Shin, Soo-Kyung; Park, Jun Yong; Yoo, Wangdon; Hong, Sun Pyo; Han, Kwang-Hyub

2013-01-01

Background/Aims Molecular diagnostic methods have enabled the rapid diagnosis of drug-resistant mutations in hepatitis B virus (HBV) and have reduced both unnecessary therapeutic interventions and medical costs. In this study we evaluated the analytical and clinical performances of the HepB Typer-Entecavir kit (GeneMatrix, Korea) in detecting entecavir-resistance-associated mutations. Methods The HepB Typer-Entecavir kit was evaluated for its limit of detection, interference, cross-reactivity, and precision using HBV reference standards made by diluting high-titer viral stocks in HBV-negative human serum. The performance of the HepB Typer-Entecavir kit for detecting mutations related to entecavir resistance was compared with direct sequencing for 396 clinical samples from 108 patients. Results Using the reference standards, the detection limit of the HepB Typer-Entecavir kit was found to be as low as 500 copies/mL. No cross-reactivity was observed, and elevated levels of various interfering substances did not adversely affect its analytical performance. The precision test conducted by repetitive analysis of 2,400 replicates with reference standards at various concentrations showed 99.9% agreement (2398/2400). The overall concordance rate between the HepB Typer-Entecavir kit and direct sequencing assays in 396 clinical samples was 99.5%. Conclusions The HepB Typer-Entecavir kit showed high reliability and precision, and comparable sensitivity and specificity for detecting mutant virus populations in reference and clinical samples in comparison with direct sequencing. Therefore, this assay would be clinically useful in the diagnosis of entecavir-resistance-associated mutations in chronic hepatitis B. PMID:24459645

The Dharma Planet Survey (DPS), a Robotic, High Cadence and High Doppler Precision Survey of Habitable Rocky Planets around Nearby Stars

NASA Astrophysics Data System (ADS)

Ge, Jian; Ma, Bo; Muterspaugh, Matthew W.; Singer, Michael; Varosi, Frank; Powell, Scott; Williamson, Michael W.; Sithajan, Sirinrat; Grieves, Nolan; Zhao, Bo; Schofield, Sidney; Liu, Jian; Cassette, Anthony; Carlson, Kevin; Klanot, Khaya; Jeram, Sarik; Barnes, Rory

2016-01-01

The Dharma Planet Survey (DPS) is to monitor ~100 nearby very bright FGKM dwarfs (most of them brighter than V=8) during 2014-2018 using the TOU optical very high resolution spectrograph (R~100,000, 380-900nm) at the 2m Automatic Spectroscopy Telescope at Fairborn Observatory initially (2014-2015) and at the dedicated 50-inch Robotic Telescope (2016-2018) on Mt. Lemmon after the telescope is installed in the fall of 2015. Operated in high vacuum (<0.01mTorr) with precisely controlled temperature (~1-2 mK), TOU has delivered ~ 1 m/s (RMS) instrument stability after the hardware upgrade in September 2015. DPS aims at reaching better than 0.5 m/s Doppler measurement precision for bright survey targets after the instrument tiny drift is carefully calibrated with Thorium-Argon and Sine reference sources. With very high RV precision and high cadence (~100 observations per target randomly spread over 450 days), a large number of rocky planets, including possible habitable ones, are expected to be detected. The survey also provides the largest single homogenous high precision RV sample of nearby stars for studying low mass planet populations and constraining various planet formation models. Early scientific results from the DPS pilot survey of 25 FGKM dwarfs will be presented.

Determination of rifampicin in human plasma by high-performance liquid chromatography coupled with ultraviolet detection after automatized solid-liquid extraction.

PubMed

Louveau, B; Fernandez, C; Zahr, N; Sauvageon-Martre, H; Maslanka, P; Faure, P; Mourah, S; Goldwirt, L

2016-12-01

A precise and accurate high-performance liquid chromatography (HPLC) quantification method of rifampicin in human plasma was developed and validated using ultraviolet detection after an automatized solid-phase extraction. The method was validated with respect to selectivity, extraction recovery, linearity, intra- and inter-day precision, accuracy, lower limit of quantification and stability. Chromatographic separation was performed on a Chromolith RP 8 column using a mixture of 0.05 m acetate buffer pH 5.7-acetonitrile (35:65, v/v) as mobile phase. The compounds were detected at a wavelength of 335 nm with a lower limit of quantification of 0.05 mg/L in human plasma. Retention times for rifampicin and 6,7-dimethyl-2,3-di(2-pyridyl) quinoxaline used as internal standard were respectively 3.77 and 4.81 min. This robust and exact method was successfully applied in routine for therapeutic drug monitoring in patients treated with rifampicin. Copyright © 2016 John Wiley & Sons, Ltd.

A Fluorescent Tile DNA Diagnocode System for In Situ Rapid and Selective Diagnosis of Cytosolic RNA Cancer Markers

PubMed Central

Park, Kyung Soo; Shin, Seung Won; Jang, Min Su; Shin, Woojung; Yang, Kisuk; Min, Junhong; Cho, Seung-Woo; Oh, Byung-Keun; Bae, Jong Wook; Jung, Sunghwan; Choi, Jeong-Woo; Um, Soong Ho

2015-01-01

Accurate cancer diagnosis often requires extraction and purification of genetic materials from cells, and sophisticated instrumentations that follow. Otherwise in order to directly treat the diagnostic materials to cells, multiple steps to optimize dose concentration and treatment time are necessary due to diversity in cellular behaviors. These processes may offer high precision but hinder fast analysis of cancer, especially in clinical situations that need rapid detection and characterization of cancer. Here we present a novel fluorescent tile DNA nanostructure delivered to cancer cytosol by employing nanoparticle technology. Its structural anisotropicity offers easy manipulation for multifunctionalities, enabling the novel DNA nanostructure to detect intracellular cancer RNA markers with high specificity within 30 minutes post treatment, while the nanoparticle property bypasses the requirement of treatment optimization, effectively reducing the complexity of applying the system for cancer diagnosis. Altogether, the system offers a precise and rapid detection of cancer, suggesting the future use in the clinical fields. PMID:26678430

COSMOS: accurate detection of somatic structural variations through asymmetric comparison between tumor and normal samples

PubMed Central

Yamagata, Koichi; Yamanishi, Ayako; Kokubu, Chikara; Takeda, Junji; Sese, Jun

2016-01-01

An important challenge in cancer genomics is precise detection of structural variations (SVs) by high-throughput short-read sequencing, which is hampered by the high false discovery rates of existing analysis tools. Here, we propose an accurate SV detection method named COSMOS, which compares the statistics of the mapped read pairs in tumor samples with isogenic normal control samples in a distinct asymmetric manner. COSMOS also prioritizes the candidate SVs using strand-specific read-depth information. Performance tests on modeled tumor genomes revealed that COSMOS outperformed existing methods in terms of F-measure. We also applied COSMOS to an experimental mouse cell-based model, in which SVs were induced by genome engineering and gamma-ray irradiation, followed by polymerase chain reaction-based confirmation. The precision of COSMOS was 84.5%, while the next best existing method was 70.4%. Moreover, the sensitivity of COSMOS was the highest, indicating that COSMOS has great potential for cancer genome analysis. PMID:26833260

Status and outlook of CHIP-TRAP: The Central Michigan University high precision Penning trap

NASA Astrophysics Data System (ADS)

Redshaw, M.; Bryce, R. A.; Hawks, P.; Gamage, N. D.; Hunt, C.; Kandegedara, R. M. E. B.; Ratnayake, I. S.; Sharp, L.

2016-06-01

At Central Michigan University we are developing a high-precision Penning trap mass spectrometer (CHIP-TRAP) that will focus on measurements with long-lived radioactive isotopes. CHIP-TRAP will consist of a pair of hyperbolic precision-measurement Penning traps, and a cylindrical capture/filter trap in a 12 T magnetic field. Ions will be produced by external ion sources, including a laser ablation source, and transported to the capture trap at low energies enabling ions of a given m / q ratio to be selected via their time-of-flight. In the capture trap, contaminant ions will be removed with a mass-selective rf dipole excitation and the ion of interest will be transported to the measurement traps. A phase-sensitive image charge detection technique will be used for simultaneous cyclotron frequency measurements on single ions in the two precision traps, resulting in a reduction in statistical uncertainty due to magnetic field fluctuations.

Direct detection of antiprotons with the Timepix3 in a new electrostatic selection beamline

NASA Astrophysics Data System (ADS)

Pacifico, N.; Aghion, S.; Alozy, J.; Amsler, C.; Ariga, A.; Ariga, T.; Bonomi, G.; Bräunig, P.; Bremer, J.; Brusa, R. S.; Cabaret, L.; Caccia, M.; Campbell, M.; Caravita, R.; Castelli, F.; Cerchiari, G.; Chlouba, K.; Cialdi, S.; Comparat, D.; Consolati, G.; Demetrio, A.; Di Noto, L.; Doser, M.; Dudarev, A.; Ereditato, A.; Evans, C.; Ferragut, R.; Fesel, J.; Fontana, A.; Gerber, S.; Giammarchi, M.; Gligorova, A.; Guatieri, F.; Haider, S.; Holmestad, H.; Huse, T.; Jordan, E.; Kellerbauer, A.; Kimura, M.; Krasnický, D.; Lagomarsino, V.; Lansonneur, P.; Lawler, G.; Lebrun, P.; Llopart, X.; Malbrunot, C.; Mariazzi, S.; Marx, L.; Matveev, V.; Mazzotta, Z.; Nebbia, G.; Nedelec, P.; Oberthaler, M.; Pagano, D.; Penasa, L.; Petracek, V.; Pistillo, C.; Prelz, F.; Prevedelli, M.; Ravelli, L.; Resch, L.; Røhne, O. M.; Rotondi, A.; Sacerdoti, M.; Sandaker, H.; Santoro, R.; Scampoli, P.; Smestad, L.; Sorrentino, F.; Spacek, M.; Storey, J.; Strojek, I. M.; Testera, G.; Tietje, I.; Tlustos, L.; Widmann, E.; Yzombard, P.; Zavatarelli, S.; Zmeskal, J.; Zurlo, N.

2016-09-01

We present here the first results obtained employing the Timepix3 for the detection and tagging of annihilations of low energy antiprotons. The Timepix3 is a recently developed hybrid pixel detector with advanced Time-of-Arrival and Time-over-Threshold capabilities and has the potential of allowing precise kinetic energy measurements of low energy charged particles from their time of flight. The tagging of the characteristic antiproton annihilation signature, already studied by our group, is enabled by the high spatial and energy resolution of this detector. In this study we have used a new, dedicated, energy selection beamline (GRACE). The line is symbiotic to the AEgIS experiment at the CERN Antiproton Decelerator and is dedicated to detector tests and possibly antiproton physics experiments. We show how the high resolution of the Timepix3 on the Time-of-Arrival and Time-over-Threshold information allows for a precise 3D reconstruction of the annihilation prongs. The presented results point at the potential use of the Timepix3 in antimatter-research experiments where a precise and unambiguous tagging of antiproton annihilations is required.

Bone mineral measurement using dual energy x ray densitometry

NASA Technical Reports Server (NTRS)

Smith, Steven W.

1989-01-01

Bone mineral measurements before and after space missions have shown that weightlessness greatly accelerates bone demineralization. Bone mineral losses as high as 1 to 3 percent per month were reported. Highly precise instrumentation is required to monitor this loss and thereby test the efficacy of treatment. During the last year, a significant improvement was made in Dual-Photon Absorptiometry by replacing the radioactive source with an x ray tube. Advantages of this system include: better precision, lower patient dose, better spacial resolution, and shorter scan times. The high precision and low radiation dose of this technique will allow detection of bone mineral changes of less than 1 percent with measurements conducted directly at the sites of interest. This will allow the required bone mineral studies to be completed in a shorter time with greater confidence.

Development of a nano-tesla magnetic field shielded chamber and highly precise AC-susceptibility measurement coil at μK temperatures

NASA Astrophysics Data System (ADS)

Kumar, Anil; Prakash, Om; Ramakrishanan, S.

2014-04-01

A special sample measurement chamber has been developed to perform experiments at ultralow temperatures and ultralow magnetic field. A high permeability material known as cryoperm 10 and Pb is used to shield the measurement space consisting of the signal detecting set-up and the sample. The detecting setup consists of a very sensitive susceptibility coil wound on OFHC Cu bobbin.

Advancing Lidar Sensors Technologies for Next Generation Landing Missions

NASA Technical Reports Server (NTRS)

Amzajerdian, Farzin; Hines, Glenn D.; Roback, Vincent E.; Petway, Larry B.; Barnes, Bruce W.; Brewster, Paul F.; Pierrottet, Diego F.; Bulyshev, Alexander

2015-01-01

Missions to solar systems bodies must meet increasingly ambitious objectives requiring highly reliable "precision landing", and "hazard avoidance" capabilities. Robotic missions to the Moon and Mars demand landing at pre-designated sites of high scientific value near hazardous terrain features, such as escarpments, craters, slopes, and rocks. Missions aimed at paving the path for colonization of the Moon and human landing on Mars need to execute onboard hazard detection and precision maneuvering to ensure safe landing near previously deployed assets. Asteroid missions require precision rendezvous, identification of the landing or sampling site location, and navigation to the highly dynamic object that may be tumbling at a fast rate. To meet these needs, NASA Langley Research Center (LaRC) has developed a set of advanced lidar sensors under the Autonomous Landing and Hazard Avoidance Technology (ALHAT) project. These lidar sensors can provide precision measurement of vehicle relative proximity, velocity, and orientation, and high resolution elevation maps of the surface during the descent to the targeted body. Recent flights onboard Morpheus free-flyer vehicle have demonstrated the viability of ALHAT lidar sensors for future landing missions to solar system bodies.

Precision Targeting With a Tracking Adaptive Optics Scanning Laser Ophthalmoscope

DTIC Science & Technology

2006-01-01

automatic high- resolution mosaic generation, and automatic blink detection and tracking re-lock were also tested. The system has the potential to become an...structures can lead to earlier detection of retinal diseases such as age-related macular degeneration (AMD) and diabetic retinopathy (DR). Combined...optics systems sense perturbations in the detected wave-front and apply corrections to an optical element that flatten the wave-front and allow near

A Perfect Match Genomic Landscape Provides a Unified Framework for the Precise Detection of Variation in Natural and Synthetic Haploid Genomes

PubMed Central

Palacios-Flores, Kim; García-Sotelo, Jair; Castillo, Alejandra; Uribe, Carina; Aguilar, Luis; Morales, Lucía; Gómez-Romero, Laura; Reyes, José; Garciarubio, Alejandro; Boege, Margareta; Dávila, Guillermo

2018-01-01

We present a conceptually simple, sensitive, precise, and essentially nonstatistical solution for the analysis of genome variation in haploid organisms. The generation of a Perfect Match Genomic Landscape (PMGL), which computes intergenome identity with single nucleotide resolution, reveals signatures of variation wherever a query genome differs from a reference genome. Such signatures encode the precise location of different types of variants, including single nucleotide variants, deletions, insertions, and amplifications, effectively introducing the concept of a general signature of variation. The precise nature of variants is then resolved through the generation of targeted alignments between specific sets of sequence reads and known regions of the reference genome. Thus, the perfect match logic decouples the identification of the location of variants from the characterization of their nature, providing a unified framework for the detection of genome variation. We assessed the performance of the PMGL strategy via simulation experiments. We determined the variation profiles of natural genomes and of a synthetic chromosome, both in the context of haploid yeast strains. Our approach uncovered variants that have previously escaped detection. Moreover, our strategy is ideally suited for further refining high-quality reference genomes. The source codes for the automated PMGL pipeline have been deposited in a public repository. PMID:29367403

Comparison of different detection methods for persistent multiple hypothesis tracking in wide area motion imagery

NASA Astrophysics Data System (ADS)

Hartung, Christine; Spraul, Raphael; Schuchert, Tobias

2017-10-01

Wide area motion imagery (WAMI) acquired by an airborne multicamera sensor enables continuous monitoring of large urban areas. Each image can cover regions of several square kilometers and contain thousands of vehicles. Reliable vehicle tracking in this imagery is an important prerequisite for surveillance tasks, but remains challenging due to low frame rate and small object size. Most WAMI tracking approaches rely on moving object detections generated by frame differencing or background subtraction. These detection methods fail when objects slow down or stop. Recent approaches for persistent tracking compensate for missing motion detections by combining a detection-based tracker with a second tracker based on appearance or local context. In order to avoid the additional complexity introduced by combining two trackers, we employ an alternative single tracker framework that is based on multiple hypothesis tracking and recovers missing motion detections with a classifierbased detector. We integrate an appearance-based similarity measure, merge handling, vehicle-collision tests, and clutter handling to adapt the approach to the specific context of WAMI tracking. We apply the tracking framework on a region of interest of the publicly available WPAFB 2009 dataset for quantitative evaluation; a comparison to other persistent WAMI trackers demonstrates state of the art performance of the proposed approach. Furthermore, we analyze in detail the impact of different object detection methods and detector settings on the quality of the output tracking results. For this purpose, we choose four different motion-based detection methods that vary in detection performance and computation time to generate the input detections. As detector parameters can be adjusted to achieve different precision and recall performance, we combine each detection method with different detector settings that yield (1) high precision and low recall, (2) high recall and low precision, and (3) best f-score. Comparing the tracking performance achieved with all generated sets of input detections allows us to quantify the sensitivity of the tracker to different types of detector errors and to derive recommendations for detector and parameter choice.

Modified automatic R-peak detection algorithm for patients with epilepsy using a portable electrocardiogram recorder.

PubMed

Jeppesen, J; Beniczky, S; Fuglsang Frederiksen, A; Sidenius, P; Johansen, P

2017-07-01

Earlier studies have shown that short term heart rate variability (HRV) analysis of ECG seems promising for detection of epileptic seizures. A precise and accurate automatic R-peak detection algorithm is a necessity in a real-time, continuous measurement of HRV, in a portable ECG device. We used the portable CE marked ePatch® heart monitor to record the ECG of 14 patients, who were enrolled in the videoEEG long term monitoring unit for clinical workup of epilepsy. Recordings of the first 7 patients were used as training set of data for the R-peak detection algorithm and the recordings of the last 7 patients (467.6 recording hours) were used to test the performance of the algorithm. We aimed to modify an existing QRS-detection algorithm to a more precise R-peak detection algorithm to avoid the possible jitter Qand S-peaks can create in the tachogram, which causes error in short-term HRVanalysis. The proposed R-peak detection algorithm showed a high sensitivity (Se = 99.979%) and positive predictive value (P+ = 99.976%), which was comparable with a previously published QRS-detection algorithm for the ePatch® ECG device, when testing the same dataset. The novel R-peak detection algorithm designed to avoid jitter has very high sensitivity and specificity and thus is a suitable tool for a robust, fast, real-time HRV-analysis in patients with epilepsy, creating the possibility for real-time seizure detection for these patients.

Clinical proteomics-driven precision medicine for targeted cancer therapy: current overview and future perspectives.

PubMed

Zhou, Li; Wang, Kui; Li, Qifu; Nice, Edouard C; Zhang, Haiyuan; Huang, Canhua

2016-01-01

Cancer is a common disease that is a leading cause of death worldwide. Currently, early detection and novel therapeutic strategies are urgently needed for more effective management of cancer. Importantly, protein profiling using clinical proteomic strategies, with spectacular sensitivity and precision, offer excellent promise for the identification of potential biomarkers that would direct the development of targeted therapeutic anticancer drugs for precision medicine. In particular, clinical sample sources, including tumor tissues and body fluids (blood, feces, urine and saliva), have been widely investigated using modern high-throughput mass spectrometry-based proteomic approaches combined with bioinformatic analysis, to pursue the possibilities of precision medicine for targeted cancer therapy. Discussed in this review are the current advantages and limitations of clinical proteomics, the available strategies of clinical proteomics for the management of precision medicine, as well as the challenges and future perspectives of clinical proteomics-driven precision medicine for targeted cancer therapy.

Precise Quantitation of MicroRNA in a Single Cell with Droplet Digital PCR Based on Ligation Reaction.

PubMed

Tian, Hui; Sun, Yuanyuan; Liu, Chenghui; Duan, Xinrui; Tang, Wei; Li, Zhengping

2016-12-06

MicroRNA (miRNA) analysis in a single cell is extremely important because it allows deep understanding of the exact correlation between the miRNAs and cell functions. Herein, we wish to report a highly sensitive and precisely quantitative assay for miRNA detection based on ligation-based droplet digital polymerase chain reaction (ddPCR), which permits the quantitation of miRNA in a single cell. In this ligation-based ddPCR assay, two target-specific oligonucleotide probes can be simply designed to be complementary to the half-sequence of the target miRNA, respectively, which avoids the sophisticated design of reverse transcription and provides high specificity to discriminate a single-base difference among miRNAs with simple operations. After the miRNA-templated ligation, the ddPCR partitions individual ligated products into a water-in-oil droplet and digitally counts the fluorescence-positive and negative droplets after PCR amplification for quantification of the target molecules, which possesses the power of precise quantitation and robustness to variation in PCR efficiency. By integrating the advantages of the precise quantification of ddPCR and the simplicity of the ligation-based PCR, the proposed method can sensitively measure let-7a miRNA with a detection limit of 20 aM (12 copies per microliter), and even a single-base difference can be discriminated in let-7 family members. More importantly, due to its high selectivity and sensitivity, the proposed method can achieve precise quantitation of miRNAs in single-cell lysate. Therefore, the ligation-based ddPCR assay may serve as a useful tool to exactly reveal the miRNAs' actions in a single cell, which is of great importance for the study of miRNAs' biofunction as well as for the related biomedical studies.

High-dimensional atom localization via spontaneously generated coherence in a microwave-driven atomic system.

PubMed

Wang, Zhiping; Chen, Jinyu; Yu, Benli

2017-02-20

We investigate the two-dimensional (2D) and three-dimensional (3D) atom localization behaviors via spontaneously generated coherence in a microwave-driven four-level atomic system. Owing to the space-dependent atom-field interaction, it is found that the detecting probability and precision of 2D and 3D atom localization behaviors can be significantly improved via adjusting the system parameters, the phase, amplitude, and initial population distribution. Interestingly, the atom can be localized in volumes that are substantially smaller than a cubic optical wavelength. Our scheme opens a promising way to achieve high-precision and high-efficiency atom localization, which provides some potential applications in high-dimensional atom nanolithography.

Fiber Scrambling for Extreme Doppler Precision

NASA Astrophysics Data System (ADS)

Spronck, Julien; Kaplan, Z.; Fischer, D.

2011-09-01

The detection of Earth-like exoplanets with the radial velocity method requires extreme Doppler precision and long-term stability in order to measure tiny reflex velocities in the host star. Recent planet searches have led to the detection of so called “super-Earths” (up to a few Earth masses) that induce radial velocity changes of about 1 m/s. However, the detection of true Earth analogs requires a precision of 10 cm/s. One of the factors limiting Doppler precision is variation in the Point Spread Function (PSF) from observation to observation due to changes in the illumination of the slit and spectrograph optics. Thus, this stability has become a focus of current instrumentation work. Fiber optics have been used since the 1980’s to couple telescopes to high-precision spectrographs, initially for simpler mechanical design and control. However, fiber optics are also naturally efficient scramblers. Scrambling refers to a fiber’s ability to produce an output beam independent of input. Our research is focused on understanding the scrambling properties of fibers with different geometries (circular, square, octagonal), different lengths and fiber sizes. Another important parameter when it comes to fibers is the so-called focal ratio degradation (FRD), which accounts for a different (faster) focal ratio after the fiber than the one sent into the fiber. In this paper, we will present new insight on fiber scrambling, FRD and what we call fiber personality, which describes differing behaviors for supposedly identical fiber.

Measuring the performance of two stationary interrogation systems for detecting downstream and upstream movement of PIT-tagged salmonids

USGS Publications Warehouse

Connolly, P.J.; Jezorek, I.G.; Martens, K.D.; Prentice, E.F.

2008-01-01

We tested the performance of two stationary interrogation systems designed for detecting the movement of fish with passive integrated transponder (PIT) tags. These systems allowed us to determine the direction of fish movement with high detection efficiency and high precision in a dynamic stream environment. We describe an indirect method for deriving an estimate for detection efficiency and the associated variance that does not rely on a known number of fish passing the system. By using six antennas arranged in a longitudinal series of three arrays, we attained detection efficiencies for downstream- and upstream-moving fish exceeding 96% during high-flow periods and approached 100% during low-flow periods for the two interrogation systems we tested. Because these systems did not rely on structural components, such as bridges or culverts, they were readily adaptable to remote, natural stream sites. Because of built-in redundancy, these systems were able to perform even with a loss of one or more antennas owing to dislodgement or electrical failure. However, the reduction in redundancy resulted in decreased efficiency and precision and the potential loss of ability to determine the direction of fish movement. What we learned about these systems should be applicable to a wide variety of other antenna configurations and to other types of PIT tags and transceivers.

Detecting Circular RNAs by RNA Fluorescence In Situ Hybridization.

PubMed

Zirkel, Anne; Papantonis, Argyris

2018-01-01

Fluorescence in situ hybridization (FISH) coupled to high-resolution microscopy is a powerful method for analyzing the subcellular localization of RNA. However, the detection of circular RNAs (circRNAs) using microscopy is challenging because the only feature of a circRNA that can be used for the probe design is its junction. Circular RNAs are expressed at varying levels, and for their efficient monitoring by FISH, background fluorescence levels need to be kept low. Here, we describe a FISH protocol coupled to high-precision localizations using a single fluorescently labeled probe spanning the circRNA junction; this allows circRNA detection in mammalian cells with high signal-to-noise ratios.

Change Detection in High-Resolution Remote Sensing Images Using Levene-Test and Fuzzy Evaluation

NASA Astrophysics Data System (ADS)

Wang, G. H.; Wang, H. B.; Fan, W. F.; Liu, Y.; Liu, H. J.

2018-04-01

High-resolution remote sensing images possess complex spatial structure and rich texture information, according to these, this paper presents a new method of change detection based on Levene-Test and Fuzzy Evaluation. It first got map-spots by segmenting two overlapping images which had been pretreated, extracted features such as spectrum and texture. Then, changed information of all map-spots which had been treated by the Levene-Test were counted to obtain the candidate changed regions, hue information (H component) was extracted through the IHS Transform and conducted change vector analysis combined with the texture information. Eventually, the threshold was confirmed by an iteration method, the subject degrees of candidate changed regions were calculated, and final change regions were determined. In this paper experimental results on multi-temporal ZY-3 high-resolution images of some area in Jiangsu Province show that: Through extracting map-spots of larger difference as the candidate changed regions, Levene-Test decreases the computing load, improves the precision of change detection, and shows better fault-tolerant capacity for those unchanged regions which are of relatively large differences. The combination of Hue-texture features and fuzzy evaluation method can effectively decrease omissions and deficiencies, improve the precision of change detection.

An ATMND/SGI based label-free and fluorescence ratiometric aptasensor for rapid and highly sensitive detection of cocaine in biofluids.

PubMed

Wang, Jiamian; Song, Jie; Wang, Xiuyun; Wu, Shuo; Zhao, Yanqiu; Luo, Pinchen; Meng, Changgong

2016-12-01

A label-free ratiometric fluorescence aptasensor has been developed for the rapid and sensitive detection of cocaine in complex biofluids. The fluorescent aptasensor is composed of a non-labeled GC-38 cocaine aptamer which serves as a basic sensing unit and two fluorophores, 2-amino-5,6,7-trimethyl-1,8-naphthyridine (ATMND) and SYBR Green I (SGI) which serves as a signal reporter and a build-in reference, respectively. The detection principle is based on a specific cocaine mediated ATMND displacement reaction and the corresponding change in the fluorescence ratio of ATMND to SGI. Due to the high affinity of the non-labeled aptamer, the good precision originated from the ratiometric method, and the good fluorescence quantum yield of the fluorophore, the aptasensor shows good analytical performance with respect to cocaine detection. Under optimal conditions, the aptasensor shows a linear range of 0.10-10μM and a low limit of detection of 56nM, with a fast response of 20s. The low limit of detection is comparable to most of the fluorescent aptasensors with signal amplification strategies and much lower than all of the unamplified cocaine aptasensors. Practical sample analysis in a series of complex biofluids, including urine, saliva and serum, also indicates the good precision, stability, and high sensitivity of the aptasensor, which may have great potential for the point-of-care screening of cocaine in complex biofluids. Copyright © 2016 Elsevier B.V. All rights reserved.

Hydroacoustic detection of dumped ammunition in the Ocean with multibeam snippet backscatter analyses. A case study from the 'Kolberger Heide' ammunition dump site (Baltic Sea, Germany)

NASA Astrophysics Data System (ADS)

Kunde, Tina; Schneider von Deimling, Jens

2016-04-01

Dumped ammunition in the sea is a matter of great concern in terms of safe navigation and environmental threads. Because corrosion of the dumped ammunition's hull is ongoing, future contamination of the ambient water by their toxic interior is likely to occur. The location of such dump sites is approximately known from historical research and ship log book analyses. Subsequent remote sensing of ammunition dumping sites (e.g. mines) on the seafloor is preferentially performed with hydro-acoustic methods such as high resolution towed side scan or by the sophisticated synthetic aperture sonar approach with autonomous underwater vehicles. However, these are time consuming and expensive procedures, while determining the precise position of individual mines remains a challenging task. To mitigate these shortcomings we suggest using ship-born high-frequency multibeam sonar in shallow water to address the task of mine detection and precise localization on the seabed. Multibeam sonar systems have improved their potential in regard to backscatter analyses significantly over the past years and nowadays present fast and accurate tools for shallow water surveying to (1) detect mines in multibeam snippet backscatter data (2) determine their precise location with high accuracy intertial navigation systems. A case study was performed at the prominent ammunition dumping site 'Kolberger Heide' (Baltic Sea, Germany) in the year 2014 using a modern hydro-acoustic multibeam echosounder system with 200-400 kHz (KONGSBERG EM2040c). With an average water depth of not even 20 m and the proximity to the shore line and dense waterways, this investigated area requires permanent navigational care. Previously, the study area was surveyed by the Navy with the very sophisticated HUGIN AUV equipped with a synthetic aperture sonar with best resolution by current technology. Following an evaluation of the collected data, various ammunition bodies on the sea floor could be clearly detected. Analyses of our shipborn multibeam snippet backscatter data now show the feasibility to detect the majority of such ammunition bodies by their distinct snippet backscatter anomaly and shape. By the use of SAPOS correction data, the navigation data of the appropriated multibeam echosounder was postprocessed, which leads to an absolute accuracy of the ammunition bodies of 0.1 m laterally. Thus, the multibeam dataset represents a study providing both, detection and precise positioning of individual mines on the seabed. Apart from the much greater efficiency of multibeam mapping sonar over towed sidescan, precise localization is important for future management of mines, may it be in regard to their dellaboration, or to evaluate if future sediment mass movement (sediment waves) may cover and obscure the ammunition bodies in the future.

g-Mode Pulsators along the Horizontal Branch

NASA Astrophysics Data System (ADS)

O'Toole, S. J.

2012-03-01

Kepler has been a boon for asteroseismology, detecting oscillations in many different stars across the HR diagram. High precision data over long timescales has allowed us to detect many g-mode oscillations in sdB stars in particular, but also in other Horizontal Branch stars. Here I point out the very similar g-mode period spacings detected in sdB and Red Clump stars, and discuss what we can learn by comparing oscillations in these objects.

Measuring masses of single bacterial whole cells with a quadrupole ion trap.

PubMed

Peng, Wen-Ping; Yang, Yi-Chang; Kang, Ming-Wei; Lee, Yuan T; Chang, Huan-Cheng

2004-09-29

A novel method has been developed to precisely measure the masses of single bacterial whole cells using a quadrupole ion trap as an electrodynamic balance. The bacterial cells were introduced into the ion trap by matrix-assisted laser desorption/ionization, confined in space by audio frequency ac fields, and detected by elastic light scattering. Mass measurement accuracy approaching 0.1% was achieved for Escherichia coli K-12 with a mass distribution of +/-3% from 60 repetitive measurements of the particles and their clusters. This is the first high-precision mass measurement reported for any intact microorganisms with masses greater than 1 x 1010 Da. The method opens new avenues for high-precision mass measurement of single microbial particles and offers an alternative approach for rapid identification of microorganisms by mass spectrometry.

Convection in Cool Stars, as Seen Through Kepler's Eyes

NASA Astrophysics Data System (ADS)

Bastien, Fabienne A.

2015-01-01

Stellar surface processes represent a fundamental limit to the detection of extrasolar planets with the currently most heavily-used techniques. As such, considerable effort has gone into trying to mitigate the impact of these processes on planet detection, with most studies focusing on magnetic spots. Meanwhile, high-precision photometric planet surveys like CoRoT and Kepler have unveiled a wide variety of stellar variability at previously inaccessible levels. We demonstrate that these newly revealed variations are not solely magnetically driven but also trace surface convection through light curve ``flicker.'' We show that ``flicker'' not only yields a simple measurement of surface gravity with a precision of ˜0.1 dex, but it may also improve our knowledge of planet properties, enhance radial velocity planet detection and discovery, and provide new insights into stellar evolution.

Capacity and precision in an animal model of visual short-term memory.

PubMed

Lara, Antonio H; Wallis, Jonathan D

2012-03-14

Temporary storage of information in visual short-term memory (VSTM) is a key component of many complex cognitive abilities. However, it is highly limited in capacity. Understanding the neurophysiological nature of this capacity limit will require a valid animal model of VSTM. We used a multiple-item color change detection task to measure macaque monkeys' VSTM capacity. Subjects' performance deteriorated and reaction times increased as a function of the number of items in memory. Additionally, we measured the precision of the memory representations by varying the distance between sample and test colors. In trials with similar sample and test colors, subjects made more errors compared to trials with highly discriminable colors. We modeled the error distribution as a Gaussian function and used this to estimate the precision of VSTM representations. We found that as the number of items in memory increases the precision of the representations decreases dramatically. Additionally, we found that focusing attention on one of the objects increases the precision with which that object is stored and degrades the precision of the remaining. These results are in line with recent findings in human psychophysics and provide a solid foundation for understanding the neurophysiological nature of the capacity limit of VSTM.

High-throughput spectral and lifetime-based FRET screening in living cells to identify small-molecule effectors of SERCA

PubMed Central

Schaaf, Tory M.; Peterson, Kurt C.; Grant, Benjamin D.; Bawaskar, Prachi; Yuen, Samantha; Li, Ji; Muretta, Joseph M.; Gillispie, Gregory D.; Thomas, David D.

2017-01-01

A robust high-throughput screening (HTS) strategy has been developed to discover small-molecule effectors targeting the sarco/endoplasmic reticulum calcium ATPase (SERCA), based on a fluorescence microplate reader that records both the nanosecond decay waveform (lifetime mode) and the complete emission spectrum (spectral mode), with high precision and speed. This spectral unmixing plate reader (SUPR) was used to screen libraries of small molecules with a fluorescence resonance energy transfer (FRET) biosensor expressed in living cells. Ligand binding was detected by FRET associated with structural rearrangements of green (GFP, donor) and red (RFP, acceptor) fluorescent proteins fused to the cardiac-specific SERCA2a isoform. The results demonstrate accurate quantitation of FRET along with high precision of hit identification. Fluorescence lifetime analysis resolved SERCA’s distinct structural states, providing a method to classify small-molecule chemotypes on the basis of their structural effect on the target. The spectral analysis was also applied to flag interference by fluorescent compounds. FRET hits were further evaluated for functional effects on SERCA’s ATPase activity via both a coupled-enzyme assay and a FRET-based calcium sensor. Concentration-response curves indicated excellent correlation between FRET and function. These complementary spectral and lifetime FRET detection methods offer an attractive combination of precision, speed, and resolution for HTS. PMID:27899691

Starspot detection and properties

NASA Astrophysics Data System (ADS)

Savanov, I. S.

2013-07-01

I review the currently available techniques for the starspots detection including the one-dimensional spot modelling of photometric light curves. Special attention will be paid to the modelling of photospheric activity based on the high-precision light curves obtained with space missions MOST, CoRoT, and Kepler. Physical spot parameters (temperature, sizes and variability time scales including short-term activity cycles) are discussed.

Design of a cost-effective laser spot tracker

NASA Astrophysics Data System (ADS)

Artan, Göktuǧ Gencehan; Sari, Hüseyin

2017-05-01

One of the most important aspects of guided systems is detection. The most convenient detection in the sense of precision can be achieved with a laser spot tracker. This study deals with a military grade, high performance and cost-effective laser spot tracker for a guided system. The aim is to develop a high field of view system that will detect a laser spot from a distance of 3 kilometers in which the target is designated from 3 kilometers with a laser. The study basically consists of the system design, modeling, producing and the conducting performance tests of the whole system.

An environmentally-friendly, highly efficient, gas pressure-assisted sample introduction system for ICP-MS and its application to detection of cadmium and lead in human plasma.

PubMed

Cao, Yupin; Deng, Biyang; Yan, Lizhen; Huang, Hongli

2017-05-15

An environmentally friendly and highly efficient gas pressure-assisted sample introduction system (GPASIS) was developed for inductively-coupled plasma mass spectrometry. A GPASIS consisting of a gas-pressure control device, a customized nebulizer, and a custom-made spray chamber was fabricated. The advantages of this GPASIS derive from its high nebulization efficiencies, small sample volume requirements, low memory effects, good precision, and zero waste emission. A GPASIS can continuously, and stably, nebulize 10% NaCl solution for more than an hour without clogging. Sensitivity, detection limits, precision, long-term stability, double charge and oxide ion levels, nebulization efficiencies, and matrix effects of the sample introduction system were evaluated. Experimental results indicated that the performance of this GPASIS, was equivalent to, or better than, those obtained by conventional sample introduction systems. This GPASIS was successfully used to determine Cd and Pb by ICP-MS in human plasma. Copyright © 2017 Elsevier B.V. All rights reserved.

Precise half-life measurement of the superallowed emitter 30S

NASA Astrophysics Data System (ADS)

Iacob, V. E.; Hardy, J. C.; Chen, L.; Horvat, V.; Bencomo, M.; Nica, N.; Park, H. I.; Roeder, B. T.; Saastamoinen, A.

2018-03-01

We have measured the half-life of 30S, the parent of a superallowed 0+→0+β transition, to a high precision using very pure sources and a 4 π proportional gas counter to detect the decay positrons. Our result for the half-life is 1.179 92(34) s. As a by-product of this measurement, we determine the half-life of its daughter, 30P, to be 2.501(2) min.

Coupling solid-phase microextraction and high-performance liquid chromatography for direct and sensitive determination of halogenated fungicides in wine.

PubMed

Millán, S; Sampedro, M C; Unceta, N; Goicolea, M A; Rodríguez, E; Barrio, R J

2003-05-02

A solid-phase microextraction (SPME) method coupled to high-performance liquid chromatography with diode array detection (HPLC-DAD) for the analysis of six organochlorine fungicides (nuarimol, triadimenol, triadimefon, folpet, vinclozolin and penconazole) in wine was developed. For this purpose, polydimethylsiloxane-divinylbenzene-coated fibers were utilized and all factors affecting throughput, precision, and accuracy of the SPME method were investigated and optimized. These factors include: matrix influence, extraction and desorption time, percentage of ethanol, pH, salt effect and desorption mode. The performed analytical procedure showed detectability ranging from 4 to 27 microg l(-1) and precision from 2.4 to 14.2% (as intra-day relative standard deviation, RSD) and 4.7-25.7% (as inter-day RSD) depending on the fungicide. The results demonstrate the suitability of the SPME-HPLC-DAD method to analyze these organochlorine fungicides in red wine.

The optical frequency comb fibre spectrometer

PubMed Central

Coluccelli, Nicola; Cassinerio, Marco; Redding, Brandon; Cao, Hui; Laporta, Paolo; Galzerano, Gianluca

2016-01-01

Optical frequency comb sources provide thousands of precise and accurate optical lines in a single device enabling the broadband and high-speed detection required in many applications. A main challenge is to parallelize the detection over the widest possible band while bringing the resolution to the single comb-line level. Here we propose a solution based on the combination of a frequency comb source and a fibre spectrometer, exploiting all-fibre technology. Our system allows for simultaneous measurement of 500 isolated comb lines over a span of 0.12 THz in a single acquisition; arbitrarily larger span are demonstrated (3,500 comb lines over 0.85 THz) by doing sequential acquisitions. The potential for precision measurements is proved by spectroscopy of acetylene at 1.53 μm. Being based on all-fibre technology, our system is inherently low-cost, lightweight and may lead to the development of a new class of broadband high-resolution spectrometers. PMID:27694981

Aircraft MSS data registration and vegetation classification of wetland change detection

USGS Publications Warehouse

Christensen, E.J.; Jensen, J.R.; Ramsey, Elijah W.; Mackey, H.E.

1988-01-01

Portions of the Savannah River floodplain swamp were evaluated for vegetation change using high resolution (5a??6 m) aircraft multispectral scanner (MSS) data. Image distortion from aircraft movement prevented precise image-to-image registration in some areas. However, when small scenes were used (200-250 ha), a first-order linear transformation provided registration accuracies of less than or equal to one pixel. A larger area was registered using a piecewise linear method. Five major wetland classes were identified and evaluated for change. Phenological differences and the variable distribution of vegetation limited wetland type discrimination. Using unsupervised methods and ground-collected vegetation data, overall classification accuracies ranged from 84 per cent to 87 per cent for each scene. Results suggest that high-resolution aircraft MSS data can be precisely registered, if small areas are used, and that wetland vegetation change can be accurately detected and monitored.

Development and Validation of High Precision Thermal, Mechanical, and Optical Models for the Space Interferometry Mission

NASA Technical Reports Server (NTRS)

Lindensmith, Chris A.; Briggs, H. Clark; Beregovski, Yuri; Feria, V. Alfonso; Goullioud, Renaud; Gursel, Yekta; Hahn, Inseob; Kinsella, Gary; Orzewalla, Matthew; Phillips, Charles

2006-01-01

SIM Planetquest (SIM) is a large optical interferometer for making microarcsecond measurements of the positions of stars, and to detect Earth-sized planets around nearby stars. To achieve this precision, SIM requires stability of optical components to tens of picometers per hour. The combination of SIM s large size (9 meter baseline) and the high stability requirement makes it difficult and costly to measure all aspects of system performance on the ground. To reduce risks, costs and to allow for a design with fewer intermediate testing stages, the SIM project is developing an integrated thermal, mechanical and optical modeling process that will allow predictions of the system performance to be made at the required high precision. This modeling process uses commercial, off-the-shelf tools and has been validated against experimental results at the precision of the SIM performance requirements. This paper presents the description of the model development, some of the models, and their validation in the Thermo-Opto-Mechanical (TOM3) testbed which includes full scale brassboard optical components and the metrology to test them at the SIM performance requirement levels.

Molecular Detection of 10 of the Most Unwanted Alien Forest Pathogens in Canada Using Real-Time PCR

PubMed Central

Lamarche, Josyanne; Potvin, Amélie; Pelletier, Gervais; Stewart, Don; Feau, Nicolas; Alayon, Dario I. O.; Dale, Angela L.; Coelho, Aaron; Uzunovic, Adnan; Bilodeau, Guillaume J.; Brière, Stephan C.; Hamelin, Richard C.; Tanguay, Philippe

2015-01-01

Invasive alien tree pathogens can cause significant economic losses as well as large-scale damage to natural ecosystems. Early detection to prevent their establishment and spread is an important approach used by several national plant protection organizations (NPPOs). Molecular detection tools targeting 10 of the most unwanted alien forest pathogens in Canada were developed as part of the TAIGA project (http://taigaforesthealth.com/). Forest pathogens were selected following an independent prioritization. Specific TaqMan real-time PCR detection assays were designed to function under homogeneous conditions so that they may be used in 96- or 384-well plate format arrays for high-throughput testing of large numbers of samples against multiple targets. Assays were validated for 1) specificity, 2) sensitivity, 3) precision, and 4) robustness on environmental samples. All assays were highly specific when evaluated against a panel of pure cultures of target and phylogenetically closely-related species. Sensitivity, evaluated by assessing the limit of detection (with a threshold of 95% of positive samples), was found to be between one and ten target gene region copies. Precision or repeatability of each assay revealed a mean coefficient of variation of 3.4%. All assays successfully allowed detection of target pathogen on positive environmental samples, without any non-specific amplification. These molecular detection tools will allow for rapid and reliable detection of 10 of the most unwanted alien forest pathogens in Canada. PMID:26274489

Precision Orbit of δ Delphini and Prospects for Astrometric Detection of Exoplanets

NASA Astrophysics Data System (ADS)

Gardner, Tyler; Monnier, John D.; Fekel, Francis C.; Williamson, Mike; Duncan, Douglas K.; White, Timothy R.; Ireland, Michael; Adams, Fred C.; Barman, Travis; Baron, Fabien; ten Brummelaar, Theo; Che, Xiao; Huber, Daniel; Kraus, Stefan; Roettenbacher, Rachael M.; Schaefer, Gail; Sturmann, Judit; Sturmann, Laszlo; Swihart, Samuel J.; Zhao, Ming

2018-03-01

Combining visual and spectroscopic orbits of binary stars leads to a determination of the full 3D orbit, individual masses, and distance to the system. We present a full analysis of the evolved binary system δ Delphini using astrometric data from the MIRC and PAVO instruments on the CHARA long-baseline interferometer, 97 new spectra from the Fairborn Observatory, and 87 unpublished spectra from the Lick Observatory. We determine the full set of orbital elements for δ Del, along with masses of 1.78 ± 0.07 M ⊙ and 1.62 ± 0.07 M ⊙ for each component, and a distance of 63.61 ± 0.89 pc. These results are important in two contexts: for testing stellar evolution models and for defining the detection capabilities for future planet searches. We find that the evolutionary state of this system is puzzling, as our measured flux ratios, radii, and masses imply a ∼200 Myr age difference between the components, using standard stellar evolution models. Possible explanations for this age discrepancy include mass transfer scenarios with a now-ejected tertiary companion. For individual measurements taken over a span of two years, we achieve <10 μas precision on the differential position with 10 minute observations. The high precision of our astrometric orbit suggests that exoplanet detection capabilities are within reach of MIRC at CHARA. We compute exoplanet detection limits around δ Del and conclude that, if this precision is extended to wider systems, we should be able to detect most exoplanets >2 M J on orbits >0.75 au around individual components of hot binary stars via differential astrometry.

Fast EEG spike detection via eigenvalue analysis and clustering of spatial amplitude distribution

NASA Astrophysics Data System (ADS)

Fukami, Tadanori; Shimada, Takamasa; Ishikawa, Bunnoshin

2018-06-01

Objective. In the current study, we tested a proposed method for fast spike detection in electroencephalography (EEG). Approach. We performed eigenvalue analysis in two-dimensional space spanned by gradients calculated from two neighboring samples to detect high-amplitude negative peaks. We extracted the spike candidates by imposing restrictions on parameters regarding spike shape and eigenvalues reflecting detection characteristics of individual medical doctors. We subsequently performed clustering, classifying detected peaks by considering the amplitude distribution at 19 scalp electrodes. Clusters with a small number of candidates were excluded. We then defined a score for eliminating spike candidates for which the pattern of detected electrodes differed from the overall pattern in a cluster. Spikes were detected by setting the score threshold. Main results. Based on visual inspection by a psychiatrist experienced in EEG, we evaluated the proposed method using two statistical measures of precision and recall with respect to detection performance. We found that precision and recall exhibited a trade-off relationship. The average recall value was 0.708 in eight subjects with the score threshold that maximized the F-measure, with 58.6  ±  36.2 spikes per subject. Under this condition, the average precision was 0.390, corresponding to a false positive rate 2.09 times higher than the true positive rate. Analysis of the required processing time revealed that, using a general-purpose computer, our method could be used to perform spike detection in 12.1% of the recording time. The process of narrowing down spike candidates based on shape occupied most of the processing time. Significance. Although the average recall value was comparable with that of other studies, the proposed method significantly shortened the processing time.

Reference geometry-based detection of (4D-)CT motion artifacts: a feasibility study

NASA Astrophysics Data System (ADS)

Werner, René; Gauer, Tobias

2015-03-01

Respiration-correlated computed tomography (4D or 3D+t CT) can be considered as standard of care in radiation therapy treatment planning for lung and liver lesions. The decision about an application of motion management devices and the estimation of patient-specific motion effects on the dose distribution relies on precise motion assessment in the planning 4D CT data { which is impeded in case of CT motion artifacts. The development of image-based/post-processing approaches to reduce motion artifacts would benefit from precise detection and localization of the artifacts. Simple slice-by-slice comparison of intensity values and threshold-based analysis of related metrics suffer from- depending on the threshold- high false-positive or -negative rates. In this work, we propose exploiting prior knowledge about `ideal' (= artifact free) reference geometries to stabilize metric-based artifact detection by transferring (multi-)atlas-based concepts to this specific task. Two variants are introduced and evaluated: (S1) analysis and comparison of warped atlas data obtained by repeated non-linear atlas-to-patient registration with different levels of regularization; (S2) direct analysis of vector field properties (divergence, curl magnitude) of the atlas-to-patient transformation. Feasibility of approaches (S1) and (S2) is evaluated by motion-phantom data and intra-subject experiments (four patients) as well as - adopting a multi-atlas strategy- inter-subject investigations (twelve patients involved). It is demonstrated that especially sorting/double structure artifacts can be precisely detected and localized by (S1). In contrast, (S2) suffers from high false positive rates.

A novel multi-scale adaptive sampling-based approach for energy saving in leak detection for WSN-based water pipelines

NASA Astrophysics Data System (ADS)

Saqib, Najam us; Faizan Mysorewala, Muhammad; Cheded, Lahouari

2017-12-01

In this paper, we propose a novel monitoring strategy for a wireless sensor networks (WSNs)-based water pipeline network. Our strategy uses a multi-pronged approach to reduce energy consumption based on the use of two types of vibration sensors and pressure sensors, all having different energy levels, and a hierarchical adaptive sampling mechanism to determine the sampling frequency. The sampling rate of the sensors is adjusted according to the bandwidth of the vibration signal being monitored by using a wavelet-based adaptive thresholding scheme that calculates the new sampling frequency for the following cycle. In this multimodal sensing scheme, the duty-cycling approach is used for all sensors to reduce the sampling instances, such that the high-energy, high-precision (HE-HP) vibration sensors have low duty cycles, and the low-energy, low-precision (LE-LP) vibration sensors have high duty cycles. The low duty-cycling (HE-HP) vibration sensor adjusts the sampling frequency of the high duty-cycling (LE-LP) vibration sensor. The simulated test bed considered here consists of a water pipeline network which uses pressure and vibration sensors, with the latter having different energy consumptions and precision levels, at various locations in the network. This is all the more useful for energy conservation for extended monitoring. It is shown that by using the novel features of our proposed scheme, a significant reduction in energy consumption is achieved and the leak is effectively detected by the sensor node that is closest to it. Finally, both the total energy consumed by monitoring as well as the time to detect the leak by a WSN node are computed, and show the superiority of our proposed hierarchical adaptive sampling algorithm over a non-adaptive sampling approach.

MONDO: a neutron tracker for particle therapy secondary emission characterisation

NASA Astrophysics Data System (ADS)

Marafini, M.; Gasparini, L.; Mirabelli, R.; Pinci, D.; Patera, V.; Sciubba, A.; Spiriti, E.; Stoppa, D.; Traini, G.; Sarti, A.

2017-04-01

Tumour control is performed in particle therapy using particles and ions, whose high irradiation precision enhances the effectiveness of the treatment, while sparing the healthy tissue surrounding the target volume. Dose range monitoring devices using photons and charged particles produced by the beam interacting with the patient’s body have already been proposed, but no attempt has been made yet to exploit the detection of the abundant neutron component. Since neutrons can release a significant dose far away from the tumour region, precise measurements of their flux, production energy and angle distributions are eagerly sought in order to improve the treatment planning system (TPS) software. It will thus be possible to predict not only the normal tissue toxicity in the target region, but also the risk of late complications in the whole body. The aforementioned issues underline the importance of an experimental effort devoted to the precise characterisation of neutron production, aimed at the measurement of their abundance, emission point and production energy. The technical challenges posed by a neutron detector aimed at high detection efficiency and good backtracking precision are addressed within the MONDO (monitor for neutron dose in hadrontherapy) project, whose main goal is to develop a tracking detector that can target fast and ultrafast neutrons. A full reconstruction of two consecutive elastic scattering interactions undergone by the neutrons inside the detector material will be used to measure their energy and direction. The preliminary results of an MC simulation performed using the FLUKA software are presented here, together with the DSiPM (digital SiPM) readout implementation. New detector readout implementations specifically tailored to the MONDO tracker are also discussed, and the neutron detection efficiency attainable with the proposed neutron tracking strategy are reported.

MONDO: a neutron tracker for particle therapy secondary emission characterisation.

PubMed

Marafini, M; Gasparini, L; Mirabelli, R; Pinci, D; Patera, V; Sciubba, A; Spiriti, E; Stoppa, D; Traini, G; Sarti, A

2017-04-21

Tumour control is performed in particle therapy using particles and ions, whose high irradiation precision enhances the effectiveness of the treatment, while sparing the healthy tissue surrounding the target volume. Dose range monitoring devices using photons and charged particles produced by the beam interacting with the patient's body have already been proposed, but no attempt has been made yet to exploit the detection of the abundant neutron component. Since neutrons can release a significant dose far away from the tumour region, precise measurements of their flux, production energy and angle distributions are eagerly sought in order to improve the treatment planning system (TPS) software. It will thus be possible to predict not only the normal tissue toxicity in the target region, but also the risk of late complications in the whole body. The aforementioned issues underline the importance of an experimental effort devoted to the precise characterisation of neutron production, aimed at the measurement of their abundance, emission point and production energy. The technical challenges posed by a neutron detector aimed at high detection efficiency and good backtracking precision are addressed within the MONDO (monitor for neutron dose in hadrontherapy) project, whose main goal is to develop a tracking detector that can target fast and ultrafast neutrons. A full reconstruction of two consecutive elastic scattering interactions undergone by the neutrons inside the detector material will be used to measure their energy and direction. The preliminary results of an MC simulation performed using the FLUKA software are presented here, together with the DSiPM (digital SiPM) readout implementation. New detector readout implementations specifically tailored to the MONDO tracker are also discussed, and the neutron detection efficiency attainable with the proposed neutron tracking strategy are reported.

The Dharma Planet Survey of Low-mass and Habitable Rocky Planets around Nearby Solar-type Stars

NASA Astrophysics Data System (ADS)

Ge, Jian; Ma, Bo; Jeram, Sarik; Sithajan, Sirinrat; Singer, Michael; Muterspaugh, Matthew W.; Varosi, Frank; Schofield, Sidney; Liu, Jian; Kimock, Benjamin; Powell, Scott; Williamson, Michael W.; Herczeg, Aleczander; Grantham, Jim; Stafford, Greg; Hille, Bruce; Rosenbaum, Gary; Savage, David; Bland, Steve; Hoscheidt, Joseph; Swindle, Scott; Waidanz, Melanie; Petersen, Robert; Grieves, Nolan; Zhao, Bo; Cassette, Anthony; Chun, Andrew; Avner, Louis; Barnes, Rory; Tan, Jonathan C.; Lopez, Eric; Dai, Ruijia

2017-01-01

The Dharma Planet Survey (DPS) aims to monitor ~150 nearby very bright FGK dwarfs (most of them brighter than V=7) during 2016-2019 using the TOU optical very high resolution spectrograph (R~100,000, 380-900nm) at the dedicated 50-inch Robotic Telescope on Mt. Lemmon. Operated in high vacuum (<0.01mTorr) with precisely controlled temperature (~1 mK), TOU has delivered ~ 0.5 m/s (RMS) long-term instrument stability, which is a factor of two times more stable than any of existing Doppler instruments to our best knowledge. DPS aims at reaching better than 0.5 m/s (a goal of 0.2 m/s) Doppler measurement precision for bright survey targets. With very high RV precision and high cadence (~100 observations per target randomly spread over 450 days), a large number of rocky planets, including possible habitable ones, are expected to be detected. The discovery of a Neptune mass planet and early survey results will be announced.

High-precision measurement of the light response of BC-418 plastic scintillator to protons with energies from 100 keV to 10 MeV

NASA Astrophysics Data System (ADS)

Henzl, Vladimir; Daub, Brian; French, Jennifer; Matthews, June; Kovash, Michael; Wender, Stephen; Famiano, Michael; Koehler, Katrina; Yuly, Mark

2010-11-01

The determination of the light response of many organic scintillators to various types of radiation has been a subject of numerous experimental as well as theoretical studies in the past. But while the data on light response to particles with energies above 1 MeV are precise and abundant, the information on light response to very low energy particles (i.e. below 1 MeV) is scarce or completely missing. In this study we measured the light response of a BC-418 scintillator to protons with energies from 100 keV to 10 MeV. The experiment was performed at Weapons Neutron Research Facility at LANSCE, Los Alamos. The neutron beam from a spallation source is used to irradiate the active target made from BC-418 plastic scintillator. The recoiled protons detected in the active target are measured in coincidence with elastically scattered incident neutrons detected by and adjacent liquid scintillator. Time of flight of the incident neutron and the knowledge of scattering geometry allow for a kinematically complete and high-precision measurement of the light response as a function of the proton energy.

Border effect-based precise measurement of any frequency signal

NASA Astrophysics Data System (ADS)

Bai, Li-Na; Ye, Bo; Xuan, Mei-Na; Jin, Yu-Zhen; Zhou, Wei

2015-12-01

Limited detection resolution leads to fuzzy areas during the measurement, and the discrimination of the border of a fuzzy area helps to use the resolution stability. In this way, measurement precision is greatly improved, hence this phenomenon is named the border effect. The resolution fuzzy area and its application should be studied to realize high-resolution measurement. During the measurement of any frequency signal, the fuzzy areas of phase-coincidence detection are always discrete and irregular. In this paper the difficulty in capturing the border information of discrete fuzzy areas is overcome and extra-high resolution measurement is implemented. Measurement precision of any frequency-signal can easily reach better than 1 × 10-11/s in a wide range of frequencies, showing the great importance of the border effect. An in-depth study of this issue has great significance for frequency standard comparison, signal processing, telecommunication, and fundamental subjects. Project supported by the National Natural Science Foundation of China (Grant Nos. 10978017 and 61201288), the Natural Science Foundation of Research Plan Projects of Shaanxi Province, China (Grant No. 2014JM2-6128), and the Sino-Poland Science and Technology Cooperation Projects (Grant No. 36-33).

Single-Cell Sequencing for Precise Cancer Research: Progress and Prospects.

PubMed

Zhang, Xiaoyan; Marjani, Sadie L; Hu, Zhaoyang; Weissman, Sherman M; Pan, Xinghua; Wu, Shixiu

2016-03-15

Advances in genomic technology have enabled the faithful detection and measurement of mutations and the gene expression profile of cancer cells at the single-cell level. Recently, several single-cell sequencing methods have been developed that permit the comprehensive and precise analysis of the cancer-cell genome, transcriptome, and epigenome. The use of these methods to analyze cancer cells has led to a series of unanticipated discoveries, such as the high heterogeneity and stochastic changes in cancer-cell populations, the new driver mutations and the complicated clonal evolution mechanisms, and the novel identification of biomarkers of variant tumors. These methods and the knowledge gained from their utilization could potentially improve the early detection and monitoring of rare cancer cells, such as circulating tumor cells and disseminated tumor cells, and promote the development of personalized and highly precise cancer therapy. Here, we discuss the current methods for single cancer-cell sequencing, with a strong focus on those practically used or potentially valuable in cancer research, including single-cell isolation, whole genome and transcriptome amplification, epigenome profiling, multi-dimensional sequencing, and next-generation sequencing and analysis. We also examine the current applications, challenges, and prospects of single cancer-cell sequencing. ©2016 American Association for Cancer Research.

A high precision dual feedback pump for unsteady perfusion of small organs.

PubMed

Sutton, D W; Mead, E H; Schmid-Schönbein, G W

1989-01-01

A dynamic pump system is described for perfusion of small organs with whole blood. The pump system was designed with the following aims: Very low flowrates to perfuse single organs in small rodents; high dynamic response for pressure or flow to permit experimenting with a harmonic signal at frequencies up to 20 Hz or by way of sharp step transients in less than 10 msec; high precision to allow detection of fine physiological details, and minimum blood cell trauma or cell activation by use of a piston principle. Representative pressure-flow curves are shown for the rat gracilis muscle after vasodilation. The curves are highly reproducible and serve as a complimentary dataset for microvascular observations in the same organ.

Solar neutrino detection in a large volume double-phase liquid argon experiment

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

Franco, D.; Agnes, P.; Giganti, C.

2016-08-01

Precision measurements of solar neutrinos emitted by specific nuclear reaction chains in the Sun are of great interest for developing an improved understanding of star formation and evolution. Given the expected neutrino fluxes and known detection reactions, such measurements require detectors capable of collecting neutrino-electron scattering data in exposures on the order of 1 ktonne-yr, with good energy resolution and extremely low background. Two-phase liquid argon time projection chambers (LAr TPCs) are under development for direct Dark Matter WIMP searches, which possess very large sensitive mass, high scintillation light yield, good energy resolution, and good spatial resolution in all threemore » cartesian directions. While enabling Dark Matter searches with sensitivity extending to the ''neutrino floor'' (given by the rate of nuclear recoil events from solar neutrino coherent scattering), such detectors could also enable precision measurements of solar neutrino fluxes using the neutrino-electron elastic scattering events. Modeling results are presented for the cosmogenic and radiogenic backgrounds affecting solar neutrino detection in a 300 tonne (100 tonne fiducial) LAr TPC operating at LNGS depth (3,800 meters of water equivalent). The results show that such a detector could measure the CNO neutrino rate with ∼15% precision, and significantly improve the precision of the {sup 7}Be and pep neutrino rates compared to the currently available results from the Borexino organic liquid scintillator detector.« less

A Perfect Match Genomic Landscape Provides a Unified Framework for the Precise Detection of Variation in Natural and Synthetic Haploid Genomes.

PubMed

Palacios-Flores, Kim; García-Sotelo, Jair; Castillo, Alejandra; Uribe, Carina; Aguilar, Luis; Morales, Lucía; Gómez-Romero, Laura; Reyes, José; Garciarubio, Alejandro; Boege, Margareta; Dávila, Guillermo

2018-04-01

We present a conceptually simple, sensitive, precise, and essentially nonstatistical solution for the analysis of genome variation in haploid organisms. The generation of a Perfect Match Genomic Landscape (PMGL), which computes intergenome identity with single nucleotide resolution, reveals signatures of variation wherever a query genome differs from a reference genome. Such signatures encode the precise location of different types of variants, including single nucleotide variants, deletions, insertions, and amplifications, effectively introducing the concept of a general signature of variation. The precise nature of variants is then resolved through the generation of targeted alignments between specific sets of sequence reads and known regions of the reference genome. Thus, the perfect match logic decouples the identification of the location of variants from the characterization of their nature, providing a unified framework for the detection of genome variation. We assessed the performance of the PMGL strategy via simulation experiments. We determined the variation profiles of natural genomes and of a synthetic chromosome, both in the context of haploid yeast strains. Our approach uncovered variants that have previously escaped detection. Moreover, our strategy is ideally suited for further refining high-quality reference genomes. The source codes for the automated PMGL pipeline have been deposited in a public repository. Copyright © 2018 by the Genetics Society of America.

Suppression of fiber modal noise induced radial velocity errors for bright emission-line calibration sources

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

Mahadevan, Suvrath; Halverson, Samuel; Ramsey, Lawrence

2014-05-01

Modal noise in optical fibers imposes limits on the signal-to-noise ratio (S/N) and velocity precision achievable with the next generation of astronomical spectrographs. This is an increasingly pressing problem for precision radial velocity spectrographs in the near-infrared (NIR) and optical that require both high stability of the observed line profiles and high S/N. Many of these spectrographs plan to use highly coherent emission-line calibration sources like laser frequency combs and Fabry-Perot etalons to achieve precision sufficient to detect terrestrial-mass planets. These high-precision calibration sources often use single-mode fibers or highly coherent sources. Coupling light from single-mode fibers to multi-mode fibersmore » leads to only a very low number of modes being excited, thereby exacerbating the modal noise measured by the spectrograph. We present a commercial off-the-shelf solution that significantly mitigates modal noise at all optical and NIR wavelengths, and which can be applied to spectrograph calibration systems. Our solution uses an integrating sphere in conjunction with a diffuser that is moved rapidly using electrostrictive polymers, and is generally superior to most tested forms of mechanical fiber agitation. We demonstrate a high level of modal noise reduction with a narrow bandwidth 1550 nm laser. Our relatively inexpensive solution immediately enables spectrographs to take advantage of the innate precision of bright state-of-the art calibration sources by removing a major source of systematic noise.« less

High precision pulsar timing and spin frequency second derivatives

NASA Astrophysics Data System (ADS)

Liu, X. J.; Bassa, C. G.; Stappers, B. W.

2018-05-01

We investigate the impact of intrinsic, kinematic and gravitational effects on high precision pulsar timing. We present an analytical derivation and a numerical computation of the impact of these effects on the first and second derivative of the pulsar spin frequency. In addition, in the presence of white noise, we derive an expression to determine the expected measurement uncertainty of a second derivative of the spin frequency for a given timing precision, observing cadence and timing baseline and find that it strongly depends on the latter (∝t-7/2). We show that for pulsars with significant proper motion, the spin frequency second derivative is dominated by a term dependent on the radial velocity of the pulsar. Considering the data sets from three Pulsar Timing Arrays, we find that for PSR J0437-4715 a detectable spin frequency second derivative will be present if the absolute value of the radial velocity exceeds 33 km s-1. Similarly, at the current timing precision and cadence, continued timing observations of PSR J1909-3744 for about another eleven years, will allow the measurement of its frequency second derivative and determine the radial velocity with an accuracy better than 14 km s-1. With the ever increasing timing precision and observing baselines, the impact of the, largely unknown, radial velocities of pulsars on high precision pulsar timing can not be neglected.

Assessment of Gamma-Ray Spectra Analysis Method Utilizing the Fireworks Algorithm for various Error Measures

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

Alamaniotis, Miltiadis; Tsoukalas, Lefteri H.

2018-01-01

Significant role in enhancing nuclear nonproliferation plays the analysis of obtained data and the inference of the presence or not of special nuclear materials in them. Among various types of measurements, gamma-ray spectra is the widest used type of data utilized for analysis in nonproliferation. In this chapter, a method that employs the fireworks algorithm (FWA) for analyzing gamma-ray spectra aiming at detecting gamma signatures is presented. In particular FWA is utilized to fit a set of known signatures to a measured spectrum by optimizing an objective function, with non-zero coefficients expressing the detected signatures. FWA is tested on amore » set of experimentally obtained measurements and various objective functions -MSE, RMSE, Theil-2, MAE, MAPE, MAP- with results exhibiting its potential in providing high accuracy and high precision of detected signatures. Furthermore, FWA is benchmarked against genetic algorithms, and multiple linear regression with results exhibiting its superiority over the rest tested algorithms with respect to precision for MAE, MAPE and MAP measures.« less

COSMOS: accurate detection of somatic structural variations through asymmetric comparison between tumor and normal samples.

PubMed

Yamagata, Koichi; Yamanishi, Ayako; Kokubu, Chikara; Takeda, Junji; Sese, Jun

2016-05-05

An important challenge in cancer genomics is precise detection of structural variations (SVs) by high-throughput short-read sequencing, which is hampered by the high false discovery rates of existing analysis tools. Here, we propose an accurate SV detection method named COSMOS, which compares the statistics of the mapped read pairs in tumor samples with isogenic normal control samples in a distinct asymmetric manner. COSMOS also prioritizes the candidate SVs using strand-specific read-depth information. Performance tests on modeled tumor genomes revealed that COSMOS outperformed existing methods in terms of F-measure. We also applied COSMOS to an experimental mouse cell-based model, in which SVs were induced by genome engineering and gamma-ray irradiation, followed by polymerase chain reaction-based confirmation. The precision of COSMOS was 84.5%, while the next best existing method was 70.4%. Moreover, the sensitivity of COSMOS was the highest, indicating that COSMOS has great potential for cancer genome analysis. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

Single-protein detection in crowded molecular environments in cryo-EM images

PubMed Central

Rickgauer, J Peter; Grigorieff, Nikolaus; Denk, Winfried

2017-01-01

We present an approach to study macromolecular assemblies by detecting component proteins’ characteristic high-resolution projection patterns, calculated from their known 3D structures, in single electron cryo-micrographs. Our method detects single apoferritin molecules in vitreous ice with high specificity and determines their orientation and location precisely. Simulations show that high spatial-frequency information and—in the presence of protein background—a whitening filter are essential for optimal detection, in particular for images taken far from focus. Experimentally, we could detect small viral RNA polymerase molecules, distributed randomly among binding locations, inside rotavirus particles. Based on the currently attainable image quality, we estimate a threshold for detection that is 150 kDa in ice and 300 kDa in 100 nm thick samples of dense biological material. DOI: http://dx.doi.org/10.7554/eLife.25648.001 PMID:28467302

Optimization of single photon detection model based on GM-APD

NASA Astrophysics Data System (ADS)

Chen, Yu; Yang, Yi; Hao, Peiyu

2017-11-01

One hundred kilometers high precision laser ranging hopes the detector has very strong detection ability for very weak light. At present, Geiger-Mode of Avalanche Photodiode has more use. It has high sensitivity and high photoelectric conversion efficiency. Selecting and designing the detector parameters according to the system index is of great importance to the improvement of photon detection efficiency. Design optimization requires a good model. In this paper, we research the existing Poisson distribution model, and consider the important detector parameters of dark count rate, dead time, quantum efficiency and so on. We improve the optimization of detection model, select the appropriate parameters to achieve optimal photon detection efficiency. The simulation is carried out by using Matlab and compared with the actual test results. The rationality of the model is verified. It has certain reference value in engineering applications.

Radio Detection of Cosmic Rays-Achievements and Future Potential

NASA Astrophysics Data System (ADS)

Huege, Tim

When modern efforts for radio detection of cosmic rays started about a decade ago, hopes were high but the true potential was unknown. Since then, we have achieved a detailed understanding of the radio emission physics and have consequently succeeded in developing sophisticated detection schemes and analysis approaches. In particular, we have demonstrated that the important air-shower parameters arrival direction, particle energy and depth of shower maximum can be reconstructed reliably from radio measurements, with a precision that is comparable with that of other detection techniques. At the same time, limitations inherent to the radio-emission mechanisms have become apparent. In this article, I shortly review the capabilities of radio detection in the very high-frequency band, and discuss the potential for future application in existing and new experiments for cosmic-ray detection.

Nonimaging speckle interferometry for high-speed nanometer-scale position detection.

PubMed

van Putten, E G; Lagendijk, A; Mosk, A P

2012-03-15

We experimentally demonstrate a nonimaging approach to displacement measurement for complex scattering materials. By spatially controlling the wavefront of the light that incidents on the material, we concentrate the scattered light in a focus on a designated position. This wavefront acts as a unique optical fingerprint that enables precise position detection of the illuminated material by simply measuring the intensity in the focus. By combining two fingerprints we demonstrate position detection along one in-plane dimension with a displacement resolution of 2.1 nm. As our approach does not require an image of the scattered field, it is possible to employ fast nonimaging detectors to enable high-speed position detection of scattering materials.

An improvement of vehicle detection under shadow regions in satellite imagery

NASA Astrophysics Data System (ADS)

Karim, Shahid; Zhang, Ye; Ali, Saad; Asif, Muhammad Rizwan

2018-04-01

The processing of satellite imagery is dependent upon the quality of imagery. Due to low resolution, it is difficult to extract accurate information according to the requirements of applications. For the purpose of vehicle detection under shadow regions, we have used HOG for feature extraction, SVM is used for classification and HOG is discerned worthwhile tool for complex environments. Shadow images have been scrutinized and found very complex for detection as observed very low detection rates therefore our dedication is towards enhancement of detection rate under shadow regions by implementing appropriate preprocessing. Vehicles are precisely detected under non-shadow regions with high detection rate than shadow regions.

Non-Gaussian precision metrology via driving through quantum phase transitions

NASA Astrophysics Data System (ADS)

Huang, Jiahao; Zhuang, Min; Lee, Chaohong

2018-03-01

We propose a scheme to realize high-precision quantum interferometry with entangled non-Gaussian states by driving the system through quantum phase transitions. The beam splitting, in which an initial nondegenerate ground state evolves into a highly entangled state, is achieved by adiabatically driving the system from a nondegenerate regime to a degenerate one. Inversely, the beam recombination, in which the output state after interrogation becomes gradually disentangled, is accomplished by adiabatically driving the system from the degenerate regime to the nondegenerate one. The phase shift, which is accumulated in the interrogation process, can then be easily inferred via population measurement. We apply our scheme to Bose condensed atoms and trapped ions and find that Heisenberg-limited precision scalings can be approached. Our proposed scheme does not require single-particle resolved detection and is within the reach of current experiment techniques.

PROSPECT - A precision oscillation and spectrum experiment

NASA Astrophysics Data System (ADS)

Langford, T. J.; PROSPECT Collaboration

2015-08-01

Segmented antineutrino detectors placed near a compact research reactor provide an excellent opportunity to probe short-baseline neutrino oscillations and precisely measure the reactor antineutrino spectrum. Close proximity to a reactor combined with minimal overburden yield a high background environment that must be managed through shielding and detector technology. PROSPECT is a new experimental effort to detect reactor antineutrinos from the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory, managed by UT Battelle for the U.S. Department of Energy. The detector will use novel lithium-loaded liquid scintillator capable of neutron/gamma pulse shape discrimination and neutron capture tagging. These enhancements improve the ability to identify neutrino inverse-beta decays (IBD) and reject background events in analysis. Results from these efforts will be covered along with their implications for an oscillation search and a precision spectrum measurement.

Communication: hybrid femtosecond/picosecond rotational coherent anti-Stokes Raman scattering thermometry using a narrowband time-asymmetric probe pulse.

PubMed

Stauffer, Hans U; Miller, Joseph D; Roy, Sukesh; Gord, James R; Meyer, Terrence R

2012-03-21

A narrowband, time-asymmetric probe pulse is introduced into the hybrid femtosecond/picosecond rotational coherent anti-Stokes Raman scattering (fs/ps RCARS) technique to provide accurate and precise single-shot, high-repetition-rate gas-phase thermometric measurements. This narrowband pulse-generated by inserting a Fabry-Pérot étalon into the probe-pulse beam path-enables frequency-domain detection of pure-rotational transitions. The unique time-asymmetric nature of this pulse, in turn, allows for detection of resonant Raman-active rotational transitions free of signal contamination by nonresonant four-wave-mixing processes while still allowing detection at short probe-pulse delays, where collisional dephasing processes are negligible. We demonstrate that this approach provides excellent single-shot thermometric accuracy (<1% error) and precision (~2.5%) in gas-phase environments. © 2012 American Institute of Physics

Methods for Multiplex Template Sampling in Digital PCR Assays

PubMed Central

Petriv, Oleh I.; Heyries, Kevin A.; VanInsberghe, Michael; Walker, David; Hansen, Carl L.

2014-01-01

The efficient use of digital PCR (dPCR) for precision copy number analysis requires high concentrations of target molecules that may be difficult or impossible to obtain from clinical samples. To solve this problem we present a strategy, called Multiplex Template Sampling (MTS), that effectively increases template concentrations by detecting multiple regions of fragmented target molecules. Three alternative assay approaches are presented for implementing MTS analysis of chromosome 21, providing a 10-fold concentration enhancement while preserving assay precision. PMID:24854517

Methods for multiplex template sampling in digital PCR assays.

PubMed

Petriv, Oleh I; Heyries, Kevin A; VanInsberghe, Michael; Walker, David; Hansen, Carl L

2014-01-01

The efficient use of digital PCR (dPCR) for precision copy number analysis requires high concentrations of target molecules that may be difficult or impossible to obtain from clinical samples. To solve this problem we present a strategy, called Multiplex Template Sampling (MTS), that effectively increases template concentrations by detecting multiple regions of fragmented target molecules. Three alternative assay approaches are presented for implementing MTS analysis of chromosome 21, providing a 10-fold concentration enhancement while preserving assay precision.

The NASA Meter Class Autonomous Telescope: Ascension Island

DTIC Science & Technology

2013-09-01

understand the debris environment by providing high fidelity data in a timely manner to protect satellites and spacecraft in orbit around the Earth...gigabytes of image data nightly. With fainter detection limits, precision detection, acquisition and tracking of targets, multi-color photometry ...ApprovedOMB No. 0704-0188 Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for

Precise Near IR Radial Velocity First Light Observations With iSHELL

NASA Astrophysics Data System (ADS)

Cale, Bryson L.; Plavchan, Peter; Gagné, Jonathan; Gao, Peter; Nishimoto, America; Tanner, Angelle; Walp, Bernie; Brinkworth, Carolyn; Johnson, John Asher; Vasisht, Gautam

2018-01-01

We present our current progress on obtaining precise radial velocities with the new iSHELL spectrograph at NASA's Infrared Telescope Facility. To obtain precise RV's, we use a methane isotopologue absorption gas cell in the calibration unit. Over the past year, we've collected 3-12 epochs of 17 bright G, K, and M dwarfs at a high SNR. By focusing on late type type stars, we obtain relatively higher SNR in the near infrared. We've successfully updated both our spectral and RV extraction pipelines, with a few exceptions. Inherent to the iSHELL data is a wavelength dependent fringing component, which must be incorporated into our model to obtain adequate RV precision. With iSHELL's predecessor, CSHELL, we obtained a precision of 3 m/s on the bright M giant SV Peg. With further progress on our fringing and telluric models, we hope to obtain a precision of <3 m/s with iSHELL, sufficient to detect terrestrial planets in the habitable zone of nearby M dwarfs.

A double sealing technique for increasing the precision of headspace-gas chromatographic analysis.

PubMed

Xie, Wei-Qi; Yu, Kong-Xian; Gong, Yi-Xian

2018-01-19

This paper investigates a new double sealing technique for increasing the precision of the headspace gas chromatographic method. The air leakage problem caused by the high pressure in the headspace vial during the headspace sampling process has a great impact to the measurement precision in the conventional headspace analysis (i.e., single sealing technique). The results (using ethanol solution as the model sample) show that the present technique is effective to minimize such a problem. The double sealing technique has an excellent measurement precision (RSD < 0.15%) and accuracy (recovery = 99.1%-100.6%) for the ethanol quantification. The detection precision of the present method was 10-20 times higher than that in earlier HS-GC work that use conventional single sealing technique. The present double sealing technique may open up a new avenue, and also serve as a general strategy for improving the performance (i.e., accuracy and precision) of headspace analysis of various volatile compounds. Copyright © 2017 Elsevier B.V. All rights reserved.

Semi-Supervised Novelty Detection with Adaptive Eigenbases, and Application to Radio Transients

NASA Technical Reports Server (NTRS)

Thompson, David R.; Majid, Walid A.; Reed, Colorado J.; Wagstaff, Kiri L.

2011-01-01

We present a semi-supervised online method for novelty detection and evaluate its performance for radio astronomy time series data. Our approach uses adaptive eigenbases to combine 1) prior knowledge about uninteresting signals with 2) online estimation of the current data properties to enable highly sensitive and precise detection of novel signals. We apply the method to the problem of detecting fast transient radio anomalies and compare it to current alternative algorithms. Tests based on observations from the Parkes Multibeam Survey show both effective detection of interesting rare events and robustness to known false alarm anomalies.

Application of HPLC with ELSD Detection for the Assessment of Azelaic Acid Impurities in Liposomal Formulation

PubMed Central

Han, Stanislaw; Karlowicz-Bodalska, Katarzyna; Ozimek, Lukasz

2013-01-01

In the course of research and development of a new pharmaceutical formulation of azelaic acid in the liposomal form, we developed a rapid and accurate method for the detection of impurities using high-performance liquid chromatography. A chromatographic column from Merck (Purospher Star RP C18, 250–4 mm (5 μm) was used in the assay, and the mobile phase gradient consisted of three phases: A—methanol : water (5 : 95) + 1.5% (v/v) acetic acid; B—water : methanol (5 : 95) + 1.5% (v/v) acetic acid; and C—chloroform. Detection of the impurities and the active substance was performed by an evaporative light-scattering detector. The method was validated for selectivity, system precision, method precision, limit of detection, and response rates. The proposed method can be used to detect impurities in the liposomal formulation of azelaic acid. The method enables separation of azelaic acid from the identified and unidentified impurities and from the excipients used in the drug form. PMID:24228008

Application of HPLC with ELSD detection for the assessment of azelaic acid impurities in liposomal formulation.

PubMed

Han, Stanislaw; Karlowicz-Bodalska, Katarzyna; Szura, Dorota; Ozimek, Lukasz; Musial, Witold

2013-01-01

In the course of research and development of a new pharmaceutical formulation of azelaic acid in the liposomal form, we developed a rapid and accurate method for the detection of impurities using high-performance liquid chromatography. A chromatographic column from Merck (Purospher Star RP C18, 250-4 mm (5 μm) was used in the assay, and the mobile phase gradient consisted of three phases: A--methanol : water (5 : 95) + 1.5% (v/v) acetic acid; B--water : methanol (5 : 95) + 1.5% (v/v) acetic acid; and C--chloroform. Detection of the impurities and the active substance was performed by an evaporative light-scattering detector. The method was validated for selectivity, system precision, method precision, limit of detection, and response rates. The proposed method can be used to detect impurities in the liposomal formulation of azelaic acid. The method enables separation of azelaic acid from the identified and unidentified impurities and from the excipients used in the drug form.

Non-Destructive Detection of Wire Rope Discontinuities from Residual Magnetic Field Images Using the Hilbert-Huang Transform and Compressed Sensing

PubMed Central

Zhang, Juwei; Tan, Xiaojiang; Zheng, Pengbo

2017-01-01

Electromagnetic methods are commonly employed to detect wire rope discontinuities. However, determining the residual strength of wire rope based on the quantitative recognition of discontinuities remains problematic. We have designed a prototype device based on the residual magnetic field (RMF) of ferromagnetic materials, which overcomes the disadvantages associated with in-service inspections, such as large volume, inconvenient operation, low precision, and poor portability by providing a relatively small and lightweight device with improved detection precision. A novel filtering system consisting of the Hilbert-Huang transform and compressed sensing wavelet filtering is presented. Digital image processing was applied to achieve the localization and segmentation of defect RMF images. The statistical texture and invariant moment characteristics of the defect images were extracted as the input of a radial basis function neural network. Experimental results show that the RMF device can detect defects in various types of wire rope and prolong the service life of test equipment by reducing the friction between the detection device and the wire rope by accommodating a high lift-off distance. PMID:28300790

Rapid determination of letrozole, citalopram and their metabolites by high performance liquid chromatography-fluorescence detection in urine: Method validation and application to real samples.

PubMed

Rodríguez, J; Castañeda, G; Muñoz, L

2013-01-15

This work reports the validation of a high precision and accuracy method for the simultaneous determination of letrozole, citalopram and their metabolites in urine by high performance liquid chromatography with fluorescence detection. Dilution (urine:mobile phase, 1:2, v/v) was the only sample preparation step. The separation was carried out in a Kromasil C(18) (150mm×4.6mm) column, and the mobile phase was phosphate buffer 80mM (pH 3.0) and acetonitrile (65:35, v/v) at a flow rate of 1.0mL/min. The analytes were detected at 295nm after excitation at 230nm. Linearity was observed in the range of 1.0-1000ng/mL for letrozole and its metabolite and 2.5-1000ng/mL for citalopram and their metabolites, with limits of detection and quantification between 0.09-1.0 and 0.27-1.65ng/mL, respectively. The precisions were satisfactory with RSDs between 0.17 and 5.71%. The accuracy was studied by spiking three urines from healthy female volunteers, and the recoveries were from 85 to 103%. The method was applied to urine samples from women under treatment for breast cancer and depression diseases. Copyright © 2012 Elsevier B.V. All rights reserved.

Ultrasensitive, self-calibrated cavity ring-down spectrometer for quantitative trace gas analysis.

PubMed

Chen, Bing; Sun, Yu R; Zhou, Ze-Yi; Chen, Jian; Liu, An-Wen; Hu, Shui-Ming

2014-11-10

A cavity ring-down spectrometer is built for trace gas detection using telecom distributed feedback (DFB) diode lasers. The longitudinal modes of the ring-down cavity are used as frequency markers without active-locking either the laser or the high-finesse cavity. A control scheme is applied to scan the DFB laser frequency, matching the cavity modes one by one in sequence and resulting in a correct index at each recorded spectral data point, which allows us to calibrate the spectrum with a relative frequency precision of 0.06 MHz. Besides the frequency precision of the spectrometer, a sensitivity (noise-equivalent absorption) of 4×10^-11  cm^-1  Hz^-1/2 has also been demonstrated. A minimum detectable absorption coefficient of 5×10^-12  cm^-1 has been obtained by averaging about 100 spectra recorded in 2  h. The quantitative accuracy is tested by measuring the CO₂ concentrations in N₂ samples prepared by the gravimetric method, and the relative deviation is less than 0.3%. The trace detection capability is demonstrated by detecting CO₂ of ppbv-level concentrations in a high-purity nitrogen gas sample. Simple structure, high sensitivity, and good accuracy make the instrument very suitable for quantitative trace gas analysis.

Direct phase-locking of a 8.6-μm quantum cascade laser to a mid-IR optical frequency comb: application to precision spectroscopy of N2O.

PubMed

Gambetta, Alessio; Cassinerio, Marco; Coluccelli, Nicola; Fasci, Eugenio; Castrillo, Antonio; Gianfrani, Livio; Gatti, Davide; Marangoni, Marco; Laporta, Paolo; Galzerano, Gianluca

2015-02-01

We developed a high-precision spectroscopic system at 8.6 μm based on direct heterodyne detection and phase-locking of a room-temperature quantum-cascade-laser against an harmonic, 250-MHz mid-IR frequency comb obtained by difference-frequency generation. The ∼30  dB signal-to-noise ratio of the detected beat-note together with the achieved closed-loop locking bandwidth of ∼500  kHz allows for a residual integrated phase noise of 0.78 rad (1 Hz-5 MHz), for an ultimate resolution of ∼21  kHz, limited by the measured linewidth of the mid-IR comb. The system was used to perform absolute measurement of line-center frequencies for the rotational components of the ν2 vibrational band of N2O, with a relative precision of 3×10(-10).

Framework Nucleic Acids-Enabled Biosensor Development.

PubMed

Yang, Fan; Li, Qian; Wang, Lihua; Zhang, Guo-Jun; Fan, Chunhai

2018-05-03

Nucleic acids have been actively exploited to develop various exquisite nanostructures due to their unparalleled programmability. Especially, framework nucleic acids (FNAs) with tailorable functionality and precise addressability hold great promise for biomedical applications. In this review, we summarize recent progress of FNA-enabled biosensing in homogeneous solutions, on heterogeneous surfaces and inside cells. We describe the strategies to translate the structural order and rigidity of FNAs to interfacial engineering with high controllability, and approaches to realize multiplexing for highly parallel in-vitro detection. We also envision the marriage of the currently available FNA toolsets with other emerging technologies to develop a new generation of biosensors for precision diagnosis and bioimaging.

Ion microscopy with resonant ionization mass spectrometry : time-of-flight depth profiling with improved isotopic precision.

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

Pellin, M. J.; Veryovkin, I. V.; Levine, J.

2010-01-01

There are four generally mutually exclusive requirements that plague many mass spectrometric measurements of trace constituents: (1) the small size (limited by the depth probed) of many interesting materials requires high useful yields to simply detect some trace elements, (2) the low concentrations of interesting elements require efficient discrimination from isobaric interferences, (3) it is often necessary to measure the depth distribution of elements with high surface and low bulk contributions, and (4) many applications require precise isotopic analysis. Resonant ionization mass spectrometry has made dramatic progress in addressing these difficulties over the past five years.

A real-time surface inspection system for precision steel balls based on machine vision

NASA Astrophysics Data System (ADS)

Chen, Yi-Ji; Tsai, Jhy-Cherng; Hsu, Ya-Chen

2016-07-01

Precision steel balls are one of the most fundament components for motion and power transmission parts and they are widely used in industrial machinery and the automotive industry. As precision balls are crucial for the quality of these products, there is an urgent need to develop a fast and robust system for inspecting defects of precision steel balls. In this paper, a real-time system for inspecting surface defects of precision steel balls is developed based on machine vision. The developed system integrates a dual-lighting system, an unfolding mechanism and inspection algorithms for real-time signal processing and defect detection. The developed system is tested under feeding speeds of 4 pcs s-1 with a detection rate of 99.94% and an error rate of 0.10%. The minimum detectable surface flaw area is 0.01 mm2, which meets the requirement for inspecting ISO grade 100 precision steel balls.

Selective and reusable iron(II)-based molecular sensor for the vapor-phase detection of alcohols.

PubMed

Naik, Anil D; Robeyns, Koen; Meunier, Christophe F; Léonard, Alexandre F; Rotaru, Aurelian; Tinant, Bernard; Filinchuk, Yaroslav; Su, Bao Lian; Garcia, Yann

2014-02-03

A mononuclear iron(II) neutral complex (1) is screened for sensing abilities for a wide spectrum of chemicals and to evaluate the response function toward physical perturbation like temperature and mechanical stress. Interestingly, 1 precisely detects methanol among an alcohol series. The sensing process is visually detectable, fatigue-resistant, highly selective, and reusable. The sensing ability is attributed to molecular sieving and subsequent spin-state change of iron centers, after a crystal-to-crystal transformation.

High Precision Wavelength Monitor for Tunable Laser Systems

NASA Technical Reports Server (NTRS)

Froggatt, Mark E. (Inventor); Childers, Brooks A. (Inventor)

2002-01-01

A solid-state apparatus for tracking the wavelength of a laser emission has a power splitter that divides the laser emission into at least three equal components. Differing phase shifts are detected and processed to track variations of the laser emission.

[Detection of rifampicin concentration in cerebrospinal fluid by online enrichment and restricted-access media coupled with high-performance liquid chromatography].

PubMed

Yang, Xiaoping; Zhang, Xiaohui; Huang, Yanping; Wang, Rong; Xia, Hua; Li, Wenbin; Guo, YouMin

2015-11-01

To establish a method for detecting rifampicin in human cerebrospinal fluid (CSF) with restricted access media coupled with high-performance liquid chromatography that allows online direct sample injection and enrichment. We used the column of restricted access media as the pre-treatment column and a C18 column as the analytical column. The mobile phase of pre-treatment column was water-methanol (95:5,V/V) and the flow rate was 1 mL/min; the mobile phase of the analytical column was methanol-acetonitrile-10 mmol/L ammonuium acetate (volume ratio of 60:5:35). The detection wavelength was 254 nm and the column temperature was set at 25 degrees celsius;. For an injection volume of 100 µL, the peak area of rifampicin was 5.33 times that for an injection volume of 20 µL, and the limit of detection was effectively improved. The calibration curve showed an excellent linear relationship (r=0.9997) between rifampicin concentrations and peak areas within the concentration range of 0.25 to 8 µg/mL in CSF. The limits of detection and quantification was 0.07 µg/mL and 0.25 µg/mL, respecetively, with intra-day and inter-day assay precisions and relative standard deviation (RSD%) all below 5%. The recoveries of rifampicin at 3 blank spiked levels (low, medium, and high) ranged from 87.69% to 102.11%. In patients taking oral rifampicin at the dose of 10 mg/kg, the average rifampicin concentration was 0.29 in the CSF at 2 h after medication. The method we established is simple and fast for detecting rifampicin in CSF and allows direct online injection and enrichment with good detection precisions and accuracies.

Capacity and precision in an animal model of visual short-term memory

PubMed Central

Lara, Antonio H.; Wallis, Jonathan D.

2013-01-01

Temporary storage of information in visual short-term memory (VSTM) is a key component of many complex cognitive abilities. However, it is highly limited in capacity. Understanding the neurophysiological nature of this capacity limit will require a valid animal model of VSTM. We used a multiple-item color change detection task to measure macaque monkeys’ VSTM capacity. Subjects’ performance deteriorated and reaction times increased as a function of the number of items in memory. Additionally, we measured the precision of the memory representations by varying the distance between sample and test colors. In trials with similar sample and test colors, subjects made more errors compared to trials with highly discriminable colors. We modeled the error distribution as a Gaussian function and used this to estimate the precision of VSTM representations. We found that as the number of items in memory increases the precision of the representations decreases dramatically. Additionally, we found that focusing attention on one of the objects increases the precision with which that object is stored and degrading the precision of the remaining. These results are in line with recent findings in human psychophysics and provide a solid foundation for understanding the neurophysiological nature of the capacity limit of VSTM. PMID:22419756

Wireless sleep monitoring headband to identify sleep and track fatigue

NASA Astrophysics Data System (ADS)

Ramasamy, Mouli; Oh, Sechang; Varadan, Vijay K.

2014-04-01

Detection of sleepiness and drowsiness in human beings has been a daunting task for both engineering and medical technologies. Accuracy, precision and promptness of detection have always been an issue that has to be dealt by technologists. Commonly, the rudimentary bio potential signals - ECG, EOG, EEG and EMG are used to classify and discriminate sleep from being awake. However, the potential drawbacks may be high false detections, low precision, obtrusiveness, aftermath analysis, etc. To overcome the disadvantages, this paper proposes the design of a wireless and a real time monitoring system to track sleep and detect fatigue. This concept involves the use of EOG and EEG to measure the blink rate and asses the person's condition. In this user friendly and intuitive approach, EOG and EEG signals are obtained by the dry gold wire nano-sensors fabricated on the inner side of a flexible headband. The acquired signals are then electrically transmitted to the data processing and transmission unit, which transmits the processed data to the receiver/monitoring module through WCDMA/GSM communication. This module is equipped with a software program to process, feature extract, analyze, display and store the information. Thereby, immediate detection of a person falling asleep is made feasible and, tracking the sleep cycle continuously provides an insight about the experienced fatigue level. The novel approach of using a wireless, real time, dry sensor on a flexible substrate reduces the obtrusiveness, and techniques adopted in the electronics and software facilitates and substantial increase in efficiency, accuracy and precision.

Achieving metrological precision limits through postselection

NASA Astrophysics Data System (ADS)

Alves, G. Bié; Pimentel, A.; Hor-Meyll, M.; Walborn, S. P.; Davidovich, L.; Filho, R. L. de Matos

2017-01-01

Postselection strategies have been proposed with the aim of amplifying weak signals, which may help to overcome detection thresholds associated with technical noise in high-precision measurements. Here we use an optical setup to experimentally explore two different postselection protocols for the estimation of a small parameter: a weak-value amplification procedure and an alternative method that does not provide amplification but nonetheless is shown to be more robust for the sake of parameter estimation. Each technique leads approximately to the saturation of quantum limits for the estimation precision, expressed by the Cramér-Rao bound. For both situations, we show that parameter estimation is improved when the postselection statistics are considered together with the measurement device.

Simultaneous Determination of Soyasaponins and Isoflavones in Soy (Glycine max L.) Products by HPTLC-densitometry-Multiple Detection.

PubMed

Shawky, Eman; Sallam, Shaimaa M

2017-11-01

A new high-throughput method was developed for the simultaneous analysis of isoflavones and soyasaponnins in Soy (Glycine max L.) products by high-performance thin-layer chromatography with densitometry and multiple detection. Silica gel was used as the stationary phase and ethyl acetate:methanol:water:acetic acid (100:20:16:1, v/v/v/v) as the mobile phase. After chromatographic development, multi-wavelength scanning was carried out by: (i) UV-absorbance measurement at 265 nm for genistin, daidzin and glycitin, (ii) Vis-absorbance measurement at 650 nm for Soyasaponins I and III, after post-chromatographic derivatization with anisaldehyde/sulfuric acid reagent. Validation of the developed method was found to meet the acceptance criteria delineated by ICH guidelines with respect to linearity, accuracy, precision, specificity and robustness. Calibrations were linear with correlation coefficients of >0.994. Intra-day precisions relative standard deviation (RSD)% of all substances in matrix were determined to be between 0.7 and 0.9%, while inter-day precisions (RSD%) ranged between 1.2 and 1.8%. The validated method was successfully applied for determination of the studied analytes in soy-based infant formula and soybean products. The new method compares favorably to other reported methods in being as accurate and precise and in the same time more feasible and cost-effective. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Low-power grating detection system chip for high-speed low-cost length and angle precision measurement

NASA Astrophysics Data System (ADS)

Hou, Ligang; Luo, Rengui; Wu, Wuchen

2006-11-01

This paper forwards a low power grating detection chip (EYAS) on length and angle precision measurement. Traditional grating detection method, such as resister chain divide or phase locked divide circuit are difficult to design and tune. The need of an additional CPU for control and display makes these methods' implementation more complex and costly. Traditional methods also suffer low sampling speed for the complex divide circuit scheme and CPU software compensation. EYAS is an application specific integrated circuit (ASIC). It integrates micro controller unit (MCU), power management unit (PMU), LCD controller, Keyboard interface, grating detection unit and other peripherals. Working at 10MHz, EYAS can afford 5MHz internal sampling rate and can handle 1.25MHz orthogonal signal from grating sensor. With a simple control interface by keyboard, sensor parameter, data processing and system working mode can be configured. Two LCD controllers can adapt to dot array LCD or segment bit LCD, which comprised output interface. PMU alters system between working and standby mode by clock gating technique to save power. EYAS in test mode (system action are more frequently than real world use) consumes 0.9mw, while 0.2mw in real world use. EYAS achieved the whole grating detection system function, high-speed orthogonal signal handling in a single chip with very low power consumption.

A novel alignment-free method for detection of lateral genetic transfer based on TF-IDF.

PubMed

Cong, Yingnan; Chan, Yao-Ban; Ragan, Mark A

2016-07-25

Lateral genetic transfer (LGT) plays an important role in the evolution of microbes. Existing computational methods for detecting genomic regions of putative lateral origin scale poorly to large data. Here, we propose a novel method based on TF-IDF (Term Frequency-Inverse Document Frequency) statistics to detect not only regions of lateral origin, but also their origin and direction of transfer, in sets of hierarchically structured nucleotide or protein sequences. This approach is based on the frequency distributions of k-mers in the sequences. If a set of contiguous k-mers appears sufficiently more frequently in another phyletic group than in its own, we infer that they have been transferred from the first group to the second. We performed rigorous tests of TF-IDF using simulated and empirical datasets. With the simulated data, we tested our method under different parameter settings for sequence length, substitution rate between and within groups and post-LGT, deletion rate, length of transferred region and k size, and found that we can detect LGT events with high precision and recall. Our method performs better than an established method, ALFY, which has high recall but low precision. Our method is efficient, with runtime increasing approximately linearly with sequence length.

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

PubMed

Noda, Naoki; Kamimura, Shinji

2008-02-01

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

Target tracking system based on preliminary and precise two-stage compound cameras

NASA Astrophysics Data System (ADS)

Shen, Yiyan; Hu, Ruolan; She, Jun; Luo, Yiming; Zhou, Jie

2018-02-01

Early detection of goals and high-precision of target tracking is two important performance indicators which need to be balanced in actual target search tracking system. This paper proposed a target tracking system with preliminary and precise two - stage compound. This system using a large field of view to achieve the target search. After the target was searched and confirmed, switch into a small field of view for two field of view target tracking. In this system, an appropriate filed switching strategy is the key to achieve tracking. At the same time, two groups PID parameters are add into the system to reduce tracking error. This combination way with preliminary and precise two-stage compound can extend the scope of the target and improve the target tracking accuracy and this method has practical value.

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

PubMed

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

2016-04-15

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

Digital PCR: A Sensitive and Precise Method for KIT D816V Quantification in Mastocytosis.

PubMed

Greiner, Georg; Gurbisz, Michael; Ratzinger, Franz; Witzeneder, Nadine; Simonitsch-Klupp, Ingrid; Mitterbauer-Hohendanner, Gerlinde; Mayerhofer, Matthias; Müllauer, Leonhard; Sperr, Wolfgang R; Valent, Peter; Hoermann, Gregor

2018-03-01

The analytically sensitive detection of KIT D816V in blood and bone marrow is important for diagnosing systemic mastocytosis (SM). Additionally, precise quantification of the KIT D816V variant allele fraction (VAF) is relevant clinically because it helps to predict multilineage involvement and prognosis in cases of advanced SM. Digital PCR (dPCR) is a promising new method for sensitive detection and accurate quantification of somatic mutations. We performed a validation study of dPCR for KIT D816V on 302 peripheral blood and bone marrow samples from 156 patients with mastocytosis for comparison with melting curve analysis after peptide nucleic acid-mediated PCR clamping (clamp-PCR) and allele-specific quantitative real-time PCR (qPCR). dPCR showed a limit of detection of 0.01% VAF with a mean CV of 8.5% and identified the mutation in 90% of patients compared with 70% for clamp-PCR ( P < 0.001). Moreover, dPCR for KIT D816V was highly concordant with qPCR without systematic deviation of results, and confirmed the clinical value of KIT D816V VAF measurements. Thus, patients with advanced SM showed a significantly higher KIT D816V VAF (median, 2.43%) compared with patients with indolent SM (median, 0.14%; P < 0.001). Moreover, dPCR confirmed the prognostic significance of a high KIT D816V VAF regarding survival ( P < 0.001). dPCR for KIT D816V provides a high degree of precision and sensitivity combined with the potential for interlaboratory standardization, which is crucial for the implementation of KIT D816V allele burden measurement. Thus, dPCR is suitable as a new method for KIT D816V testing in patients with mastocytosis. © 2017 American Association for Clinical Chemistry.

Advances in Multicollector ICPMS for precise and accurate isotope ratio measurements of Uranium isotopes

NASA Astrophysics Data System (ADS)

Bouman, C.; Lloyd, N. S.; Schwieters, J.

2011-12-01

The accurate and precise determination of uranium isotopes is challenging, because of the large dynamic range posed by the U isotope abundances and the limited available sample material. Various mass spectrometric techniques are used for the measurement of U isotopes, where TIMS is the most accepted and accurate one. Multicollector inductively coupled plasma mass spectrometry (MC-ICPMS) can offer higher productivity compared to TIMS, but is traditionally limited by low efficiency of sample utilisation. This contribution will discuss progress in MC-ICPMS for detecting 234U, 235U, 236U and 238U in various uranium reference materials from IRMM and NBL. The Thermo Scientific NEPTUNE Plus with Jet Interface offers a modified dry plasma ICP interface using a large interface pump combined with a special set of sample and skimmer cones giving ultimate sensitivity for all elements across the mass range. For uranium, an ion yield of > 3 % was reported previously [1]. The NEPTUNE Plus also offers Multi Ion Counting using discrete dynode electron multipliers as well as two high abundance-sensitivity filters to discriminate against peak tailing effects on 234U and 236U originating from the major uranium beams. These improvements in sensitivity and dynamic range allow accurate measurements of 234U, 235U and 236U abundances on very small samples and at low concentration. In our approach, minor U isotopes 234U and 236U were detected on ion counters with high abundance sensitivity filters, whereas 235U and 238U were detected on Faraday Cups using a high gain current amplifier (10e12 Ohm) for 235U. Precisions and accuracies for 234U and 236U were down to ~1%. For 235U, subpermil levels were reached.

Comparison of Relative Bias, Precision, and Efficiency of Sampling Methods for Natural Enemies of Soybean Aphid (Hemiptera: Aphididae).

PubMed

Bannerman, J A; Costamagna, A C; McCornack, B P; Ragsdale, D W

2015-06-01

Generalist natural enemies play an important role in controlling soybean aphid, Aphis glycines (Hemiptera: Aphididae), in North America. Several sampling methods are used to monitor natural enemy populations in soybean, but there has been little work investigating their relative bias, precision, and efficiency. We compare five sampling methods: quadrats, whole-plant counts, sweep-netting, walking transects, and yellow sticky cards to determine the most practical methods for sampling the three most prominent species, which included Harmonia axyridis (Pallas), Coccinella septempunctata L. (Coleoptera: Coccinellidae), and Orius insidiosus (Say) (Hemiptera: Anthocoridae). We show an important time by sampling method interaction indicated by diverging community similarities within and between sampling methods as the growing season progressed. Similarly, correlations between sampling methods for the three most abundant species over multiple time periods indicated differences in relative bias between sampling methods and suggests that bias is not consistent throughout the growing season, particularly for sticky cards and whole-plant samples. Furthermore, we show that sticky cards produce strongly biased capture rates relative to the other four sampling methods. Precision and efficiency differed between sampling methods and sticky cards produced the most precise (but highly biased) results for adult natural enemies, while walking transects and whole-plant counts were the most efficient methods for detecting coccinellids and O. insidiosus, respectively. Based on bias, precision, and efficiency considerations, the most practical sampling methods for monitoring in soybean include walking transects for coccinellid detection and whole-plant counts for detection of small predators like O. insidiosus. Sweep-netting and quadrat samples are also useful for some applications, when efficiency is not paramount. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Performance of a newly designed continuous soot monitoring system (COSMOS).

PubMed

Miyazaki, Yuzo; Kondo, Yutaka; Sahu, Lokesh K; Imaru, Junichi; Fukushima, Nobuhiko; Kano, Minoru

2008-10-01

We designed a continuous soot monitoring system (COSMOS) for fully automated, high-sensitivity, continuous measurement of light absorption by black carbon (BC) aerosols. The instrument monitors changes in transmittance across an automatically advancing quartz fiber filter tape using an LED at a 565 nm wavelength. To achieve measurements with high sensitivity and a lower detectable light absorption coefficient, COSMOS uses a double-convex lens and optical bundle pipes to maintain high light intensity and signal data are obtained at 1000 Hz. In addition, sampling flow rate and optical unit temperature are actively controlled. The inlet line for COSMOS is heated to 400 degrees C to effectively volatilize non-refractory aerosol components that are internally mixed with BC. In its current form, COSMOS provides BC light absorption measurements with a detection limit of 0.45 Mm(-1) (0.045 microg m(-3) for soot) for 10 min. The unit-to-unit variability is estimated to be within +/- 1%, demonstrating its high reproducibility. The absorption coefficients determined by COSMOS agreed with those by a particle soot absorption photometer (PSAP) to within 1% (r2 = 0.97). The precision (+/- 0.60 Mm(-1)) for 10 min integrated data was better than that of PSAP and an aethalometer under our operating conditions. These results showed that COSMOS achieved both an improved detection limit and higher precision for the filter-based light absorption measurements of BC compared to the existing methods.

Development and validation of liquid chromatographic and UV derivative spectrophotometric methods for the determination of famciclovir in pharmaceutical dosage forms.

PubMed

Srinubabu, Gedela; Sudharani, Batchu; Sridhar, Lade; Rao, Jvln Seshagiri

2006-06-01

A high-performance liquid chromatographic method and a UV derivative spectrophotometric method for the determination of famciclovir, a highly active antiviral agent, in tablets were developed in the present work. The various parameters, such as linearity, precision, accuracy, specificity, robustness, limit of detection and limit of quantitation were studied according to International Conference on Harmonization guidelines. HPLC was carried out by using the reversed-phase technique on an RP-18 column with a mobile phase composed of 50 mM monobasic phosphate buffer and methanol (50 : 50; v/v), adjusted to pH 3.05 with orthophosphoric acid. The mobile phase was pumped at a flow rate of 1 ml/min and detection was made at 242 nm with UV dual absorbance detector. The first derivative UV spectrophotometric method was performed at 226.5 nm. Statistical analysis was done by Student's t-test and F-test, which showed no significant difference between the results obtained by the two methods. The proposed methods are highly sensitive, precise and accurate and therefore can be used for its Intended purpose.

Surface plasmon resonance spectroscopy sensor and methods for using same

DOEpatents

Anderson, Brian Benjamin; Nave, Stanley Eugene

2002-01-01

A surface plasmon resonance ("SPR") probe with a detachable sensor head and system and methods for using the same in various applications is described. The SPR probe couples fiber optic cables directly to an SPR substrate that has a generally planar input surface and a generally curved reflecting surface, such as a substrate formed as a hemisphere. Forming the SPR probe in this manner allows the probe to be miniaturized and operate without the need for high precision, expensive and bulky collimating or focusing optics. Additionally, the curved reflecting surface of the substrate can be coated with one or multiple patches of sensing medium to allow the probe to detect for multiple analytes of interest or to provide multiple readings for comparison and higher precision. Specific applications for the probe are disclosed, including extremely high sensitive relative humidity and dewpoint detection for, e.g., moisture-sensitive environment such as volatile chemical reactions. The SPR probe disclosed operates with a large dynamic range and provides extremely high quality spectra despite being robust enough for field deployment and readily manufacturable.

Toward Spectroscopically Detecting the Global Latitudinal Temperature Variation on the Solar Surface

NASA Astrophysics Data System (ADS)

Takeda, Y.; UeNo, S.

2017-09-01

A very slight rotation-induced latitudinal temperature variation (presumably on the order of several kelvin) on the solar surface is theoretically expected. While recent high-precision solar brightness observations reported its detection, confirmation by an alternative approach using the strengths of spectral lines is desirable, for which reducing the noise due to random fluctuation caused by atmospheric inhomogeneity is critical. Toward this difficult task, we carried out a pilot study of spectroscopically investigating the relative variation of temperature (T) at a number of points in the solar circumference region near to the limb (where latitude dependence should be detectable, if any exists) based on the equivalent widths (W) of 28 selected lines in the 5367 - 5393 Å and 6075 - 6100 Å regions. We paid special attention to i) clarifying which types of lines should be employed and ii) how much precision is attainable in practice. We found that lines with strong T-sensitivity (|log W/log T|) should be used and that very weak lines should be avoided because they inevitably suffer strong relative fluctuations (Δ W/W). Our analysis revealed that a precision of Δ T/T ≈ 0.003 (corresponding to ≈ 15 K) can be achieved at best by a spectral line with comparatively large |log W/log T|, although this can possibly be further improved When a number of lines are used all together. Accordingly, if many such favorable lines could be measured with subpercent precision of Δ W/W and by averaging the resulting Δ T/T from each line, the random noise would eventually be reduced to ≲ 1 K and detection of a very subtle amount of global T-gradient might be possible.

Comparison of low cost measurement techniques for long-term monitoring of atmospheric ammonia.

PubMed

Sutton, M A; Miners, B; Tang, Y S; Milford, C; Wyers, G P; Duyzer, J H; Fowler, D

2001-10-01

An inter-comparison of techniques for long-term sampling of atmospheric ammonia (NH3) was conducted with a view to establishing a national network with > 50 sites. Key requirements were for: a low cost system, simplicity and durability to enable a postal exchange with local site operators, a precision of < +/- 20% for monthly sampling at expected NH3 concentrations of 1-2 micrograms m-3, a detection limit sufficient to resolve the small NH3 concentrations (< 0.2 microgram m-3) expected in remote parts of the UK, and a quantitative means to establish quality control. Five sampling methods were compared: A, a commercially available membrane diffusion tube (exposed in triplicate), with membranes removed immediately after sampling; B, the above method, with the membranes left in place until analysis; C, open-ended diffusion tubes (exposed with 4 replicates); D, a new active sampling diffusion denuder system; and E, an active sampling bubbler system. Method D consisted of two 0.1 m acid coated glass denuders in series with sampling at approximately 0.3 l min-1. These methods were deployed at 6 locations in the UK and the Netherlands and compared against reference estimates. Method D was the most precise and sensitive of the techniques compared, with a detection limit of < 0.1 microgram m-3. The bubbler provided a less precise estimate of NH3 concentration, and also suffered several practical drawbacks. The diffusion tubes were found to correlate with the reference at high concentrations (> 3 micrograms m-3), but were less precise and overestimated NH3 at smaller concentrations. Of the passive methods, A was the most precise and C the least precise. On the basis of the results, method D has been implemented in the national network, together with application of method A to explore spatial variability in regions with expected high NH3 concentrations.

Atom Interferometer Technologies in Space for Gravity Mapping and Gravity Science

NASA Astrophysics Data System (ADS)

Williams, Jason; Chiow, Sheng-Wey; Kellogg, James; Kohel, James; Yu, Nan

2015-05-01

Atom interferometers utilize the wave-nature of atomic gases for precision measurements of inertial forces, with potential applications ranging from gravity mapping for planetary science to unprecedented tests of fundamental physics with quantum gases. The high stability and sensitivity intrinsic to these devices already place them among the best terrestrial sensors available for measurements of gravitational accelerations, rotations, and gravity gradients, with the promise of several orders of magnitude improvement in their detection sensitivity in microgravity. Consequently, multiple precision atom-interferometer-based projects are under development at the Jet Propulsion Laboratory, including a dual-atomic-species interferometer that is to be integrated into the Cold Atom Laboratory onboard the International Space Station and a highly stable gravity gradiometer in a transportable design relevant for earth science measurements. We will present JPL's activities in the use of precision atom interferometry for gravity mapping and gravitational wave detection in space. Our recent progresses bringing the transportable JPL atom interferometer instrument to be competitive with the state of the art and simulations of the expected capabilities of a proposed flight project will also be discussed. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

Precise optical observation of 0.5-GPa shock waves in condensed materials

NASA Astrophysics Data System (ADS)

Nagayama, Kunihito; Mori, Yasuhito

1999-06-01

Precision optical observation method was developed to study impact-generated high-pressure shock waves in condensed materials. The present method makes it possible to sensitively detect the shock waves of the relatively low shock stress around 0.5 GPa. The principle of the present method is based on the use of total internal reflection by triangular prisms placed on the free surface of a target assembly. When a plane shock wave arrives at the free surface, the light reflected from the prisms extinguishes instantaneously. The reason is that the total internal reflection changes to the reflection depending on micron roughness of the free surface after the shock arrival. The shock arrival at the bottom face of the prisms can be detected here by two kinds of methods, i.e., a photographic method and a gauge method. The photographic method is an inclined prism method of using a high-speed streak camera. The shock velocity and the shock tilt angle can be estimated accurately from an obtained streak photograph. While in the gauge method, an in-material PVDF stress gauge is combined with an optical prism-pin. The PVDF gauge records electrically the stress profile behind the shockwave front, and the Hugoniot data can be precisely measured by combining the prism pin with the PVDF gauge.

Development of a novel low frequency GPR system for ultra-deep detection in Mine

NASA Astrophysics Data System (ADS)

Xu, Xianlei; Peng, Suping; Yang, Feng

2016-04-01

Mine disasters sources is the main source of the underground coal mine accidents in China. This paper describes the development of a novel explosion proof ground penetrating radar (GPR) for mine disasters sources detection, aiming to solve the current problems of the small detection range and low precision in the mine advanced detection in China. A high performance unipolar pulse transmitting unit is developed by using avalanche transistors, and an effective pulse excitation source network. And a new pluggable combined low-frequency antenna involving three frequencies with 12.5MHz, 25 MHz and 50MHz, is designed and developed. The plate-type structure is designed, aiming to enhance the directivity of the antenna, and the achievement of the antenna impedance matching is implemented in the feed point based on the extensions interface design, enhancing the antenna bandwidth and reducing the standing wave interference. Moreover, a high precision stepper delay circuit is designed by transforming the number of the operational amplifier step and using the differential compensation between the metal-oxide semiconductor field effect transistors, aiming to improve the accuracy of the signal acquisition system. In order to adapt to the mine environment, the explosion-proof design is implemented for the GPR system, including the host, transmitter, receiver, battery box, antenna, and other components.Mine detection experiments is carried out and the results show: the novel GPR system can effectively detect the location and depth of the geological disasters source with the depth greater than30 m and the diameter greater than 3m, the maximum detection depth can be up to 80m, which break the current detection depth limitations within 30m, providing an effective technical support for the ultra-deep mine disasters detection and the safety problems in coal mine production.

High-precision and low-cost vibration generator for low-frequency calibration system

NASA Astrophysics Data System (ADS)

Li, Rui-Jun; Lei, Ying-Jun; Zhang, Lian-Sheng; Chang, Zhen-Xin; Fan, Kuang-Chao; Cheng, Zhen-Ying; Hu, Peng-Hao

2018-03-01

Low-frequency vibration is one of the harmful factors that affect the accuracy of micro-/nano-measuring machines because its amplitude is significantly small and it is very difficult to avoid. In this paper, a low-cost and high-precision vibration generator was developed to calibrate an optical accelerometer, which is self-designed to detect low-frequency vibration. A piezoelectric actuator is used as vibration exciter, a leaf spring made of beryllium copper is used as an elastic component, and a high-resolution, low-thermal-drift eddy current sensor is applied to investigate the vibrator’s performance. Experimental results demonstrate that the vibration generator can achieve steady output displacement with frequency range from 0.6 Hz to 50 Hz, an analytical displacement resolution of 3.1 nm and an acceleration range from 3.72 mm s-2 to 1935.41 mm s-2 with a relative standard deviation less than 1.79%. The effectiveness of the high-precision and low-cost vibration generator was verified by calibrating our optical accelerometer.

The proton radius puzzle

NASA Astrophysics Data System (ADS)

Bonesini, Maurizio

2017-12-01

The FAMU (Fisica degli Atomi Muonici) experiment has the goal to measure precisely the proton Zemach radius, thus contributing to the solution of the so-called proton radius "puzzle". To this aim, it makes use of a high-intensity pulsed muon beam at RIKEN-RAL impinging on a cryogenic hydrogen target with an high-Z gas admixture and a tunable mid-IR high power laser, to measure the hyperfine (HFS) splitting of the 1S state of the muonic hydrogen. From the value of the exciting laser frequency, the energy of the HFS transition may be derived with high precision ( 10-5) and thus, via QED calculations, the Zemach radius of the proton. The experimental apparatus includes a precise fiber-SiPMT beam hodoscope and a crown of eight LaBr3 crystals and a few HPGe detectors for detection of the emitted characteristic X-rays. Preliminary runs to optimize the gas target filling and its operating conditions have been taken in 2014 and 2015-2016. The final run, with the pump laser to drive the HFS transition, is expected in 2018.

Detection of wheat powdery mildew by differentiating background factors using hyperspectral imaging

USDA-ARS?s Scientific Manuscript database

Accurate assessment of crop disease severities is the key for precision application of pesticides to prevent disease infestation. In-situ hyperspectral imaging technology can provide high-resolution imagery with spectra for rapid identification of crop disease and determining disease infestation pat...

Determination of three steroidal saponins from Ophiopogon japonicus (Liliaceae) via high-performance liquid chromatography with mass spectrometry.

PubMed

Wang, Yongyi; Xu, Jinzhong; Qu, Haibin

2013-01-01

A simple and accurate analytical method was developed for simultaneous quantification of three steroidal saponins in the roots of Ophiopogon japonicus via high-performance liquid chromatography (HPLC) with mass spectrometry (MS) in this study. Separation was performed on a Tigerkin C(18) column and detection was performed by mass spectrometry. A mobile phase consisted of 0.02% formic acid in water (v/v) and 0.02% formic acid in acetonitrile (v/v) was used with a flow rate of 0.5 mL min(-1). The quantitative HPLC-MS method was validated for linearity, precision, repeatability, stability, recovery, limits of detection and quantification. This developed method provides good linearity (r >0.9993), intra- and inter-day precisions (RSD <4.18%), repeatability (RSD <5.05%), stability (RSD <2.08%) and recovery (93.82-102.84%) for three steroidal saponins. It could be considered as a suitable quality control method for O. japonicus.

Dissociations of the number and precision of visual short-term memory representations in change detection.

PubMed

Xie, Weizhen; Zhang, Weiwei

2017-11-01

The present study dissociated the number (i.e., quantity) and precision (i.e., quality) of visual short-term memory (STM) representations in change detection using receiver operating characteristic (ROC) and experimental manipulations. Across three experiments, participants performed both recognition and recall tests of visual STM using the change-detection task and the continuous color-wheel recall task, respectively. Experiment 1 demonstrated that the estimates of the number and precision of visual STM representations based on the ROC model of change-detection performance were robustly correlated with the corresponding estimates based on the mixture model of continuous-recall performance. Experiments 2 and 3 showed that the experimental manipulation of mnemonic precision using white-noise masking and the experimental manipulation of the number of encoded STM representations using consolidation masking produced selective effects on the corresponding measures of mnemonic precision and the number of encoded STM representations, respectively, in both change-detection and continuous-recall tasks. Altogether, using the individual-differences (Experiment 1) and experimental dissociation (Experiment 2 and 3) approaches, the present study demonstrated the some-or-none nature of visual STM representations across recall and recognition.

[Evaluation of the Performance of Two Kinds of Anti-TP Enzyme-Linked Immunosorbent Assay].

PubMed

Gao, Nan; Huang, Li-Qin; Wang, Rui; Jia, Jun-Jie; Wu, Shuo; Zhang, Jing; Ge, Hong-Wei

2018-06-01

To evaluate the accuracy and precision of 2 kinds of anti-treponema pallidum (anti-TP) ELISA reagents in our laboratory for detecting the anti-TP in voluntary blood donors, so as to provide the data support for use of ELISA reagents after introduction of chemiluminescene immunoassay (CLIA). The route detection of anti-TP was performed by using 2 kinds of ELISA reagents, then 546 responsive positive samples detected by anti-TP ELISA were collected, and the infections status of samples confirmed by treponema pallidum particle agglutination (TPPA) test was identified. The confirmed results of responsive samples detected by 2 kinds of anti-TP ELISA reagents were compared, the accuracy of 2 kinds of anti-TP ELISA reagents was analyzed by drawing ROC and comparing area under curve (AUC), and precision of 2 kinds of anti-TP ELISA reagents was compared by statistical analysis of quality control data from 7.1 2016 to 6.30 2017. There were no statistical difference in confirmed positive rate of responsive samples and weak positive samples between 2 kinds of anti-TP ELISA reagents. The responsive samples detected by 2 kinds of anti-TP ELISA reagents accounted for 85.53%(467/546) of all responsive samples, the positive rate confirmed by TPPA test was 82.87%. 44 responsive samples detected by anti-TP ELISA reagent A and 35 responsive samples detected by anti-TP ELISA reagent B were confirmed to be negative by TPPA test. Comparison of AUC showed that the accuracy of 2 kinds of anti-TP ELISA reagents was more high, the difference between 2 reagents was not statistically significant. The coefficient of variation (CV) of anti-TP ELISA reagent A and B was 14.98% and 18.04% respectively, which met the precision requirement of ELISA test. The accuracy and precision of 2 kinds of anti-TP ELISA reagents used in our laboratory are similar, and using any one of anti-TP ELISA reagents all can satisfy the requirements of blood screening.

Efficient Generation of Gene-Modified Pigs Harboring Precise Orthologous Human Mutation via CRISPR/Cas9-Induced Homology-Directed Repair in Zygotes.

PubMed

Zhou, Xiaoyang; Wang, Lulu; Du, Yinan; Xie, Fei; Li, Liang; Liu, Yu; Liu, Chuanhong; Wang, Shiqiang; Zhang, Shibing; Huang, Xingxu; Wang, Yong; Wei, Hong

2016-01-01

Precise genetic mutation of model animals is highly valuable for functional investigation of human mutations. Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated 9 (Cas9)-induced homology-directed repair (HDR) is usually used for precise genetic mutation, being limited by the relatively low efficiency compared with that of non-homologous end joining (NHEJ). Although inhibition of NHEJ was shown to enhance HDR-derived mutation, in this work, without inhibition of NHEJ, we first generated gene-modified pigs harboring precise orthologous human mutation (Sox10 c.A325>T) via CRISPR/Cas9-induced HDR in zygotes using single-strand oligo DNA (ssODN) as template with an efficiency as high as 80%, indicating that pig zygotes exhibited high activities of HDR relative to NHEJ and were highly amendable to genetic mutation via CIRSPR/Cas9-induced HDR. Besides, we found a higher concentration of ssODN remarkably reduced HDR-derived mutation in pig zygotes, suggesting a possible balance for optimal HDR-derived mutation in zygotes between the excessive accessibility to HDR templates and the activities of HDR relative to NHEJ which appeared to be negatively correlated to ssODN concentration. In addition, the HDR-derived mutation, as well as those from NHEJ, extensively integrated into various tissues including gonad of founder pig without detected off-targeting, suggesting CRISPR/Cas9-induced HDR in zygotes is a reliable approach for precise genetic mutation in pigs. © 2015 WILEY PERIODICALS, INC.

Detection of non-Gaussian fluctuations in a quantum point contact.

PubMed

Gershon, G; Bomze, Yu; Sukhorukov, E V; Reznikov, M

2008-07-04

An experimental study of current fluctuations through a tunable transmission barrier, a quantum point contact, is reported. We measure the probability distribution function of transmitted charge with precision sufficient to extract the first three cumulants. To obtain the intrinsic quantities, corresponding to voltage-biased barrier, we employ a procedure that accounts for the response of the external circuit and the amplifier. The third cumulant, obtained with a high precision, is found to agree with the prediction for the statistics of transport in the non-Poissonian regime.

Detection of Non-Gaussian Fluctuations in a Quantum Point Contact

NASA Astrophysics Data System (ADS)

Gershon, G.; Bomze, Yu.; Sukhorukov, E. V.; Reznikov, M.

2008-07-01

An experimental study of current fluctuations through a tunable transmission barrier, a quantum point contact, is reported. We measure the probability distribution function of transmitted charge with precision sufficient to extract the first three cumulants. To obtain the intrinsic quantities, corresponding to voltage-biased barrier, we employ a procedure that accounts for the response of the external circuit and the amplifier. The third cumulant, obtained with a high precision, is found to agree with the prediction for the statistics of transport in the non-Poissonian regime.

Design of automatic leveling and centering system of theodolite

NASA Astrophysics Data System (ADS)

Liu, Chun-tong; He, Zhen-Xin; Huang, Xian-xiang; Zhan, Ying

2012-09-01

To realize the theodolite automation and improve the azimuth Angle measurement instrument, the theodolite automatic leveling and centering system with the function of leveling error compensation is designed, which includes the system solution, key components selection, the mechanical structure of leveling and centering, and system software solution. The redesigned leveling feet are driven by the DC servo motor; and the electronic control center device is installed. Using high precision of tilt sensors as horizontal skew detection sensors ensures the effectiveness of the leveling error compensation. Aiming round mark center is located using digital image processing through surface array CCD; and leveling measurement precision can reach the pixel level, which makes the theodolite accurate centering possible. Finally, experiments are conducted using the automatic leveling and centering system of the theodolite. The results show the leveling and centering system can realize automatic operation with high centering accuracy of 0.04mm.The measurement precision of the orientation angle after leveling error compensation is improved, compared with that of in the traditional method. Automatic leveling and centering system of theodolite can satisfy the requirements of the measuring precision and its automation.

Multi-GNSS high-rate RTK, PPP and novel direct phase observation processing method: application to precise dynamic displacement detection

NASA Astrophysics Data System (ADS)

Paziewski, Jacek; Sieradzki, Rafal; Baryla, Radoslaw

2018-03-01

This paper provides the methodology and performance assessment of multi-GNSS signal processing for the detection of small-scale high-rate dynamic displacements. For this purpose, we used methods of relative (RTK) and absolute positioning (PPP), and a novel direct signal processing approach. The first two methods are recognized as providing accurate information on position in many navigation and surveying applications. The latter is an innovative method for dynamic displacement determination with the use of GNSS phase signal processing. This method is based on the developed functional model with parametrized epoch-wise topocentric relative coordinates derived from filtered GNSS observations. Current regular kinematic PPP positioning, as well as medium/long range RTK, may not offer coordinate estimates with subcentimeter precision. Thus, extended processing strategies of absolute and relative GNSS positioning have been developed and applied for displacement detection. The study also aimed to comparatively analyze the developed methods as well as to analyze the impact of combined GPS and BDS processing and the dependence of the results of the relative methods on the baseline length. All the methods were implemented with in-house developed software allowing for high-rate precise GNSS positioning and signal processing. The phase and pseudorange observations collected with a rate of 50 Hz during the field test served as the experiment’s data set. The displacements at the rover station were triggered in the horizontal plane using a device which was designed and constructed to ensure a periodic motion of GNSS antenna with an amplitude of ~3 cm and a frequency of ~4.5 Hz. Finally, a medium range RTK, PPP, and direct phase observation processing method demonstrated the capability of providing reliable and consistent results with the precision of the determined dynamic displacements at the millimeter level. Specifically, the research shows that the standard deviation of the displacement residuals obtained as the difference between a benchmark-ultra-short baseline RTK solution and selected scenarios ranged between 1.1 and 3.4 mm. At the same time, the differences in the mean amplitude of the oscillations derived from the established scenarios did not exceed 1.3 mm, whereas the frequency of the motion detected with the use of Fourier transformation was the same.

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

Kuruma, K.; Takamiya, D.; Ota, Y.

We demonstrate precise and quick detection of the positions of quantum dots (QDs) embedded in two-dimensional photonic crystal nanocavities. We apply this technique to investigate the QD position dependence of the optical coupling between the QD and the nanocavity. We use a scanning electron microscope (SEM) operating at a low acceleration voltage to detect surface bumps induced by the QDs buried underneath. This enables QD detection with a sub-10 nm precision. We then experimentally measure the vacuum Rabi spectra to extract the optical coupling strengths (gs) between single QDs and cavities, and compare them to the values estimated by a combinationmore » of the SEM-measured QD positions and electromagnetic cavity field simulations. We found a highly linear relationship between the local cavity field intensities and the QD-cavity gs, suggesting the validity of the point dipole approximation used in the estimation of the gs. The estimation using SEM has a small standard deviation of ±6.2%, which potentially enables the high accuracy prediction of g prior to optical measurements. Our technique will play a key role for deeply understanding the interaction between QDs and photonic nanostructures and for advancing QD-based cavity quantum electrodynamics.« less

[Determination of doping in human urine by gas chromatography-high resolution mass spectrometry].

PubMed

Xing, Yan-Yi; Liu, Xin; Zhang, Yu-Mei; Wang, Xiao-Bing; Xu, You-Xuan

2012-12-01

A method was evaluated for determination of twenty-one doping (including nandrolone, boldenone and methandienone) in human urine by gas chromatography-high resolution mass spectrometry. Samples were prepared by liquid-liquid extraction, concentrated, TMS derivatization and limit of detection at ng x mL(-1) by MID/GC/HRMS. According to the code of the World Anti-Doping Agency (WADA), precision and recoveries of the procedure were evaluated by replicate analysis (n = 6), the recoveries in the range of 66%-103%, with the RSD below 10.0%. The precision within the day of the method with three different concentrations was also determined RSD were less than 9.5%, 10.0% and 9.7%.

Tiled fuzzy Hough transform for crack detection

NASA Astrophysics Data System (ADS)

Vaheesan, Kanapathippillai; Chandrakumar, Chanjief; Mathavan, Senthan; Kamal, Khurram; Rahman, Mujib; Al-Habaibeh, Amin

2015-04-01

Surface cracks can be the bellwether of the failure of any component under loading as it indicates the component's fracture due to stresses and usage. For this reason, crack detection is indispensable for the condition monitoring and quality control of road surfaces. Pavement images have high levels of intensity variation and texture content, hence the crack detection is difficult. Moreover, shallow cracks result in very low contrast image pixels making their detection difficult. For these reasons, studies on pavement crack detection is active even after years of research. In this paper, the fuzzy Hough transform is employed, for the first time to detect cracks on any surface. The contribution of texture pixels to the accumulator array is reduced by using the tiled version of the Hough transform. Precision values of 78% and a recall of 72% are obtaining for an image set obtained from an industrial imaging system containing very low contrast cracking. When only high contrast crack segments are considered the values move to mid to high 90%.

Fabrication of an infrared Shack-Hartmann sensor by combining high-speed single-point diamond milling and precision compression molding processes.

PubMed

Zhang, Lin; Zhou, Wenchen; Naples, Neil J; Yi, Allen Y

2018-05-01

A novel fabrication method by combining high-speed single-point diamond milling and precision compression molding processes for fabrication of discontinuous freeform microlens arrays was proposed. Compared with slow tool servo diamond broaching, high-speed single-point diamond milling was selected for its flexibility in the fabrication of true 3D optical surfaces with discontinuous features. The advantage of single-point diamond milling is that the surface features can be constructed sequentially by spacing the axes of a virtual spindle at arbitrary positions based on the combination of rotational and translational motions of both the high-speed spindle and linear slides. By employing this method, each micro-lenslet was regarded as a microstructure cell by passing the axis of the virtual spindle through the vertex of each cell. An optimization arithmetic based on minimum-area fabrication was introduced to the machining process to further increase the machining efficiency. After the mold insert was machined, it was employed to replicate the microlens array onto chalcogenide glass. In the ensuing optical measurement, the self-built Shack-Hartmann wavefront sensor was proven to be accurate in detecting an infrared wavefront by both experiments and numerical simulation. The combined results showed that precision compression molding of chalcogenide glasses could be an economic and precision optical fabrication technology for high-volume production of infrared optics.

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

Not Available

The GEM collaboration was formed in June 1991 to develop a major detector for the SSC. The primary physics objectives of GEM are those central to the motivation for the SSC, to study high p{sub T} physics - exemplified by the search for Higgs bosons - and to search for new physics beyond the standard model. The authors present in this Technical Design Report (TDR) a detector with broad capabilities for the discovery and subsequent study of electroweak symmetry breaking, the origin of mass and flavor, and other physics requiring precise measurements of gammas, electrons, and muons - hence themore » name, GEM. In addition, as a design goal, they have taken care to provide the robustness needed to do the physics that requires high luminosity. Finally, good coverage and hermeticity allow the detection of missing transverse energy, E{sub T}. The GEM design emphasizes clean identification and high resolution measurement of the primary physics signatures for high p{sub T} physics. The approach is to make precise energy measurements that maximize the sensitivity to rare narrow resonances, to detect the elementary interaction products (quarks, leptons, and photons), and to build in the features required to reduce backgrounds.« less

One-laser-based generation/detection of Brillouin dynamic grating and its application to distributed discrimination of strain and temperature.

PubMed

Zou, Weiwen; He, Zuyuan; Hotate, Kazuo

2011-01-31

This paper presents a novel scheme to generate and detect Brillouin dynamic grating in a polarization-maintaining optical fiber based on one laser source. Precise measurement of Brillouin dynamic grating spectrum is achieved benefiting from that the pump, probe and readout waves are coherently originated from the same laser source. Distributed discrimination of strain and temperature is also achieved with high accuracy.

Simultaneous determination of four 5-hydroxy polymethoxyflavones by reversed-phase high performance liquid chromatography with electrochemical detection.

PubMed

Dong, Ping; Qiu, Peiju; Zhu, Yi; Li, Shiming; Ho, Chi-Tang; McClements, David Julian; Xiao, Hang

2010-01-29

Accumulating evidence has suggested the potential health-promoting effects of 5-hydroxy polymethoxyflavones (5-OH-PMFs) naturally existing in citrus genus. However, research efforts are hampered by the lack of reliable and sensitive methods for their determination in plant materials and biological samples. Using reversed-phase high performance liquid chromatography (HPLC) equipped with electrochemical (EC) detection, we have developed a fast and highly sensitive method for quantification of four 5-OH-PMFs, namely 5-hydroxy-6,7,8,3',4'-pentamethoxyflavone, 5-hydroxy-3,6,7,8,3',4'-hexamethoxyflavone, 5-hydroxy-6,7,4'-trimethoxyflavone, and 5-hydroxy-6,7,8,4'-tetramethoxyflavone. The method was fully validated in terms of linearity, accuracy and precision. The limit of detection (LOD) was determined as being between 0.65 and 1.8ng/mL (ppb), demonstrating an over 160 times higher sensitivity in comparison with the previously reported method using UV detection. The recovery rate of the method was between 96.17% and 110.82%, and the precision for the retention times and peak areas was all below 13%. The method was successfully used to quantify 5-OH-PMFs with a wide range of abundance in the citrus products and preparations, such as orange juice, citrus peel, and dried tangerine peel. The quantification method for 5-OH-PMFs developed herein could be useful for the nutritional and pharmacological studies of these compounds in future. Copyright (c) 2009 Elsevier B.V. All rights reserved.

High-cadence spectroscopy of M-dwarfs - II. Searching for stellar pulsations with HARPS

NASA Astrophysics Data System (ADS)

Berdiñas, Z. M.; Rodríguez-López, C.; Amado, P. J.; Anglada-Escudé, G.; Barnes, J. R.; MacDonald, J.; Zechmeister, M.; Sarmiento, L. F.

2017-08-01

Stellar oscillations appear all across the Hertzsprung-Russell diagram. Recent theoretical studies support their existence also in the atmosphere of M dwarfs. These studies predict for them short periodicities ranging from 20 min to 3 h. Our Cool Tiny Beats (CTB) programme aims at finding these oscillations for the very first time. With this goal, CTB explores the short time domain of M dwarfs using radial velocity data from the High Accuracy Radial velocity Planet Searcher (HARPS)-European Southern Observatory and HARPS-N high-precision spectrographs. Here we present the results for the two most long-term stable targets observed to date with CTB, GJ 588 and GJ 699 (I.e. Barnard's star). In the first part of this work we detail the correction of several instrumental effects. These corrections are especially relevant when searching for subnight signals. Results show no significant signals in the range where M dwarfs pulsations were predicted. However, we estimate that stellar pulsations with amplitudes larger than ˜0.5 m s-1 can be detected with a 90 per cent completeness with our observations. This result, along with the excess of power regions detected in the periodograms, opens the possibility of non-resolved very low amplitude pulsation signals. Next generation more precise instrumentation would be required to detect such oscillations. However, the possibility of detecting pulsating M-dwarf stars with larger amplitudes is feasible due to the short size of the analysed sample. This motivates the need for completeness of the CTB survey.

Monitoring on Xi'an ground fissures deformation with TerraSAR-X data

USGS Publications Warehouse

Zhao, C.; Zhang, Q.; Zhu, W.; Lu, Z.

2012-01-01

Owing to the fine resolution of TerraSAR-X data provided since 2007, this paper applied 6 TerraSAR data (strip mode) during 3rd Dec. 2009 to 23rd Mar. 2010 to detect and monitor the active fissures over Xi'an region. Three themes have been designed for high precision detection and monitoring of Xi'an-Chang'an fissures, as small baseline subsets (SBAS) to test the atmospheric effects of differential interferograms pair stepwise, 2-pass differential interferogram with very short baseline perpendicular to generate the whole deformation map with 44 days interval, and finally, corner reflector (CR) technique was used to closely monitor the relative deformation time series between two CRs settled crossing two ground fissures. Results showed that TerraSAR data are a good choice for small-scale ground fissures detection and monitoring, while special considerations should be taken for their great temporal and baseline decorrelation. Secondly, ground fissures in Xi'an were mostly detected at the joint section of stable and deformable regions. Lastly, CR-InSAR had potential ability to monitor relative deformation crossing fissures with millimeter precision.

On precise phase difference measurement approach using border stability of detection resolution.

PubMed

Bai, Lina; Su, Xin; Zhou, Wei; Ou, Xiaojuan

2015-01-01

For the precise phase difference measurement, this paper develops an improved dual phase coincidence detection method. The measurement resolution of the digital phase coincidence detection circuits is always limited, for example, only at the nanosecond level. This paper reveals a new way to improve the phase difference measurement precision by using the border stability of the circuit detection fuzzy areas. When a common oscillator signal is used to detect the phase coincidence with the two comparison signals, there will be two detection fuzzy areas for the reason of finite detection resolution surrounding the strict phase coincidence. Border stability of fuzzy areas and the fluctuation difference of the two fuzzy areas can be even finer than the picoseconds level. It is shown that the system resolution obtained only depends on the stability of the circuit measurement resolution which is much better than the measurement device resolution itself.

Detecting and locating light atoms from high-resolution STEM images: The quest for a single optimal design.

PubMed

Gonnissen, J; De Backer, A; den Dekker, A J; Sijbers, J; Van Aert, S

2016-11-01

In the present paper, the optimal detector design is investigated for both detecting and locating light atoms from high resolution scanning transmission electron microscopy (HR STEM) images. The principles of detection theory are used to quantify the probability of error for the detection of light atoms from HR STEM images. To determine the optimal experiment design for locating light atoms, use is made of the so-called Cramér-Rao Lower Bound (CRLB). It is investigated if a single optimal design can be found for both the detection and location problem of light atoms. Furthermore, the incoming electron dose is optimised for both research goals and it is shown that picometre range precision is feasible for the estimation of the atom positions when using an appropriate incoming electron dose under the optimal detector settings to detect light atoms. Copyright © 2016 Elsevier B.V. All rights reserved.

LDRD Annual Report.

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

Sweany, Melinda

2017-10-01

This is a high-risk effort to leverage knowledge gained from previous work, which focused on detector development leading to better energy resolution and reconstruction errors. This work seeks to enable applications that require precise elemental characterization of materials, such as chemical munitions remediation, offering the potential to close current detection gaps.

Large depth high-precision FMCW tomography using a distributed feedback laser array

NASA Astrophysics Data System (ADS)

DiLazaro, Thomas; Nehmetallah, George

2018-02-01

Swept-source optical coherence tomography (SS-OCT) has been widely employed in the medical industry for the high resolution imaging of subsurface biological structures. SS-OCT typically exhibits axial resolutions on the order of tens of microns at speeds of hundreds of kilohertz. Using the same coherent heterodyne detection technique, frequency modulated continuous wave (FMCW) ladar has been used for highly precise ranging for distances up to kilometers. Distributed feedback lasers (DFBs) have been used as a simple and inexpensive source for FMCW ranging. Here, we use a bandwidth-combined DFB array for sub-surface volume imaging at a 27 μm axial resolution over meters of distance. 2D and 3D tomographic images of several semi-transparent and diffuse objects at distances up to 10 m will be presented.

Detection method based on Kalman filter for high speed rail defect AE signal on wheel-rail rolling rig

NASA Astrophysics Data System (ADS)

Hao, Qiushi; Shen, Yi; Wang, Yan; Zhang, Xin

2018-01-01

Nondestructive test (NDT) of rails has been carried out intermittently in traditional approaches, which highly restricts the detection efficiency under rapid development of high speed railway nowadays. It is necessary to put forward a dynamic rail defect detection method for rail health monitoring. Acoustic emission (AE) as a practical real-time detection technology takes advantage of dynamic AE signal emitted from plastic deformation of material. Detection capacities of AE on rail defects have been verified due to its sensitivity and dynamic merits. Whereas the application under normal train service circumstance has been impeded by synchronous background noises, which are directly linked to the wheel speed. In this paper, surveys on a wheel-rail rolling rig are performed to investigate defect AE signals with varying speed. A dynamic denoising method based on Kalman filter is proposed and its detection effectiveness and flexibility are demonstrated by theory and computational results. Moreover, after comparative analysis of modelling precision at different speeds, it is predicted that the method is also applicable for high speed condition beyond experiments.

Precise determination of anthropometric dimensions by means of image processing methods for estimating human body segment parameter values.

PubMed

Baca, A

1996-04-01

A method has been developed for the precise determination of anthropometric dimensions from the video images of four different body configurations. High precision is achieved by incorporating techniques for finding the location of object boundaries with sub-pixel accuracy, the implementation of calibration algorithms, and by taking into account the varying distances of the body segments from the recording camera. The system allows automatic segment boundary identification from the video image, if the boundaries are marked on the subject by black ribbons. In connection with the mathematical finite-mass-element segment model of Hatze, body segment parameters (volumes, masses, the three principal moments of inertia, the three local coordinates of the segmental mass centers etc.) can be computed by using the anthropometric data determined videometrically as input data. Compared to other, recently published video-based systems for the estimation of the inertial properties of body segments, the present algorithms reduce errors originating from optical distortions, inaccurate edge-detection procedures, and user-specified upper and lower segment boundaries or threshold levels for the edge-detection. The video-based estimation of human body segment parameters is especially useful in situations where ease of application and rapid availability of comparatively precise parameter values are of importance.

Cosmic ray measurements with LOPES: Status and recent results

NASA Astrophysics Data System (ADS)

Schröder, F. G.; Apel, W. D.; Arteaga-Velázquez, J. C.; Bähren, L.; Bekk, K.; Bertaina, M.; Biermann, P. L.; Blümer, J.; Bozdog, H.; Brancus, I. M.; Chiavassa, A.; Daumiller, K.; de Souza, V.; Di Pierro, F.; Doll, P.; Engel, R.; Falcke, H.; Fuchs, B.; Fuhrmann, D.; Gemmeke, H.; Grupen, C.; Haungs, A.; Heck, D.; Hörandel, J. R.; Horneffer, A.; Huber, D.; Huege, T.; Isar, P. G.; Kampert, K.-H.; Kang, D.; Krömer, O.; Kuijpers, J.; Link, K.; Łuczak, P.; Ludwig, M.; Mathes, H. J.; Melissas, M.; Morello, C.; Oehlschläger, J.; Palmieri, N.; Pierog, T.; Rautenberg, J.; Rebel, H.; Roth, M.; Rühle, C.; Saftoiu, A.; Schieler, H.; Schmidt, A.; Sima, O.; Toma, G.; Trinchero, G. C.; Weindl, A.; Wochele, J.; Zabierowski, J.; Zensus, J. A.

2013-05-01

LOPES is a digital antenna array at the Karlsruhe Institute of Technology, Germany, for cosmic-ray air-shower measurements. Triggered by the co-located KASCADE-Grande air-shower array, LOPES detects the radio emission of air showers via digital radio interferometry. We summarize the status of LOPES and recent results. In particular, we present an update on the reconstruction of the primary-particle properties based on almost 500 events above 100PeV. With LOPES, the arrival direction can be reconstructed with a precision of at least 0.65°, and the energy with a precision of at least 20%, which, however, does not include systematic uncertainties on the absolute energy scale. For many particle and astrophysics questions the reconstruction of the atmospheric depth of the shower maximum, Xmax, is important, since it yields information on the type of the primary particle and its interaction with the atmosphere. Recently, we found experimental evidence that the slope of the radio lateral distribution is indeed sensitive to the longitudinal development of the air shower, but unfortunately, the Xmax precision at LOPES is limited by the high level of anthropogenic radio background. Nevertheless, the developed methods can be transferred to next generation experiments with lower background, which should provide an Xmax precision competitive to other detection technologies.

Mechanisms underlying the temporal precision of sound coding at the inner hair cell ribbon synapse

PubMed Central

Moser, Tobias; Neef, Andreas; Khimich, Darina

2006-01-01

Our auditory system is capable of perceiving the azimuthal location of a low frequency sound source with a precision of a few degrees. This requires the auditory system to detect time differences in sound arrival between the two ears down to tens of microseconds. The detection of these interaural time differences relies on network computation by auditory brainstem neurons sharpening the temporal precision of the afferent signals. Nevertheless, the system requires the hair cell synapse to encode sound with the highest possible temporal acuity. In mammals, each auditory nerve fibre receives input from only one inner hair cell (IHC) synapse. Hence, this single synapse determines the temporal precision of the fibre. As if this was not enough of a challenge, the auditory system is also capable of maintaining such high temporal fidelity with acoustic signals that vary greatly in their intensity. Recent research has started to uncover the cellular basis of sound coding. Functional and structural descriptions of synaptic vesicle pools and estimates for the number of Ca2+ channels at the ribbon synapse have been obtained, as have insights into how the receptor potential couples to the release of synaptic vesicles. Here, we review current concepts about the mechanisms that control the timing of transmitter release in inner hair cells of the cochlea. PMID:16901948

Superallowed Fermi β-Decay Studies with SCEPTAR and the 8π Gamma-Ray Spectrometer

NASA Astrophysics Data System (ADS)

Koopmans, K. A.

2005-04-01

The 8π Gamma-Ray Spectrometer, operating at TRIUMF in Vancouver Canada, is a high-precision instrument for detecting the decay radiations from exotic nuclei. In 2003, a new beta-scintillating array called SCEPTAR was installed within the 8π Spectrometer. With these two systems, precise measurements of half-lives and branching ratios can be made, specifically on certain nuclei which exhibit Superallowed Fermi 0+ → 0+ β-decay. These data can be used to determine the value of δC, an isospin symmetry-breaking (Coulomb) correction factor to good precision. As this correction factor is currently one of the leading sources of error in the unitarity test of the CKM matrix, a precise determination of its value could help to eliminate any possible "trivial" explanation of the seeming departure of current experimental data from Standard Model predictions.

Assessment of Gamma-Ray-Spectra Analysis Method Utilizing the Fireworks Algorithm for Various Error Measures

DOE PAGES

Alamaniotis, Miltiadis; Tsoukalas, Lefteri H.

2018-01-01

The analysis of measured data plays a significant role in enhancing nuclear nonproliferation mainly by inferring the presence of patterns associated with special nuclear materials. Among various types of measurements, gamma-ray spectra is the widest utilized type of data in nonproliferation applications. In this paper, a method that employs the fireworks algorithm (FWA) for analyzing gamma-ray spectra aiming at detecting gamma signatures is presented. In particular, FWA is utilized to fit a set of known signatures to a measured spectrum by optimizing an objective function, where non-zero coefficients express the detected signatures. FWA is tested on a set of experimentallymore » obtained measurements optimizing various objective functions—MSE, RMSE, Theil-2, MAE, MAPE, MAP—with results exhibiting its potential in providing highly accurate and precise signature detection. Finally and furthermore, FWA is benchmarked against genetic algorithms and multiple linear regression, showing its superiority over those algorithms regarding precision with respect to MAE, MAPE, and MAP measures.« less

Quantum-limited evanescent single molecule sensing.

NASA Astrophysics Data System (ADS)

Bowen, Warwick; Mauranyapin, Nicolas; Madsen, Lars; Taylor, Michael; Waleed, Muhammad

Sensors that are able to detect and track single unlabeled biomolecules are an important tool both to understand biomolecular dynamics and interactions, and for medical diagnostics operating at their ultimate detection limits. Recently, exceptional sensitivity has been achieved using the strongly enhanced evanescent fields provided by optical microcavities and plasmonic resonators. However, at high field intensities photodamage to the biological specimen becomes increasingly problematic. Here, we introduce a new approach that combines dark field illumination and heterodyne detection in an optical nanofibre. This allows operation at the fundamental precision limit introduced by quantisation of light. We achieve state-of-the-art sensitivity with a four order-of-magnitude reduction in optical intensity. This enables quantum noise limited tracking of single biomolecules as small as 3.5 nm and surface-molecule interactions to be montored over extended periods. By achieving quantum noise limited precision, our approach provides a pathway towards quantum-enhanced single-molecule biosensors. We acknkowledge financial support from AFOSR and AOARD.

Single photon detection and timing in the Lunar Laser Ranging Experiment.

NASA Technical Reports Server (NTRS)

Poultney, S. K.

1972-01-01

The goals of the Lunar Laser Ranging Experiment lead to the need for the measurement of a 2.5 sec time interval to an accuracy of a nanosecond or better. The systems analysis which included practical retroreflector arrays, available laser systems, and large telescopes led to the necessity of single photon detection. Operation under all background illumination conditions required auxiliary range gates and extremely narrow spectral and spatial filters in addition to the effective gate provided by the time resolution. Nanosecond timing precision at relatively high detection efficiency was obtained using the RCA C31000F photomultiplier and Ortec 270 constant fraction of pulse-height timing discriminator. The timing accuracy over the 2.5 sec interval was obtained using a digital interval with analog vernier ends. Both precision and accuracy are currently checked internally using a triggerable, nanosecond light pulser. Future measurements using sub-nanosecond laser pulses will be limited by the time resolution of single photon detectors.

Improved cancer diagnostics by different image processing techniques on OCT images

NASA Astrophysics Data System (ADS)

Kanawade, Rajesh; Lengenfelder, Benjamin; Marini Menezes, Tassiana; Hohmann, Martin; Kopfinger, Stefan; Hohmann, Tim; Grabiec, Urszula; Klämpfl, Florian; Gonzales Menezes, Jean; Waldner, Maximilian; Schmidt, Michael

2015-07-01

Optical-coherence tomography (OCT) is a promising non-invasive, high-resolution imaging modality which can be used for cancer diagnosis and its therapeutic assessment. However, speckle noise makes detection of cancer boundaries and image segmentation problematic and unreliable. Therefore, to improve the image analysis for a precise cancer border detection, the performance of different image processing algorithms such as mean, median, hybrid median filter and rotational kernel transformation (RKT) for this task is investigated. This is done on OCT images acquired from an ex-vivo human cancerous mucosa and in vitro by using cultivated tumour applied on organotypical hippocampal slice cultures. The preliminary results confirm that the border between the healthy and the cancer lesions can be identified precisely. The obtained results are verified with fluorescence microscopy. This research can improve cancer diagnosis and the detection of borders between healthy and cancerous tissue. Thus, it could also reduce the number of biopsies required during screening endoscopy by providing better guidance to the physician.

Development of a Method to Assess the Precision Of the z-axis X-ray Beam Collimation in a CT Scanner

NASA Astrophysics Data System (ADS)

Kim, Yon-Min

2018-05-01

Generally X-ray equipment specifies the beam collimator for the accuracy measurement as a quality control item, but the computed tomography (CT) scanner with high dose has no collimator accuracy measurement item. If the radiation dose is to be reduced, an important step is to check if the beam precisely collimates at the body part for CT scan. However, few ways are available to assess how precisely the X-ray beam is collimated. In this regard, this paper provides a way to assess the precision of z-axis X-ray beam collimation in a CT scanner. After the image plate cassette had been exposed to the X-ray beam, the exposed width was automatically detected by using a computer program developed by the research team to calculate the difference between the exposed width and the imaged width (at isocenter). The result for the precision of z-axis X-ray beam collimation showed that the exposed width was 3.8 mm and the overexposure was high at 304% when a narrow beam of a 1.25 mm imaged width was used. In this study, the precision of the beam collimation of the CT scanner, which is frequently used for medical services, was measured in a convenient way by using the image plate (IP) cassette.

Novel drug and soluble target tolerant antidrug antibody assay for therapeutic antibodies bearing the P329G mutation.

PubMed

Wessels, Uwe; Schick, Eginhard; Ritter, Mirko; Kowalewsky, Frank; Heinrich, Julia; Stubenrauch, Kay

2017-06-01

Bridging immunoassays for detection of antidrug antibodies (ADAs) are typically susceptible to high concentrations of residual drug. Sensitive drug-tolerant assays are, therefore, needed. An immune complex assay to detect ADAs against therapeutic antibodies bearing Pro329Gly mutation was established. The assay uses antibodies specific for the Pro329Gly mutation for capture and human soluble Fcγ receptor for detection. When compared with a bridging assay, the new assay showed similar precision, high sensitivity to IgG1 ADA and dramatically improved drug tolerance. However, it was not able to detect early (IgM-based) immune responses. Applied in combination with a bridging assay, the novel assay serves as orthogonal assay for immunogenicity assessment and allows further characterization of ADA responses.

Validation of high throughput screening of human sera for detection of anti-PA IgG by Enzyme-Linked Immunosorbent Assay (ELISA) as an emergency response to an anthrax incident

PubMed Central

Semenova, Vera A.; Steward-Clark, Evelene; Maniatis, Panagiotis; Epperson, Monica; Sabnis, Amit; Schiffer, Jarad

2017-01-01

To improve surge testing capability for a response to a release of Bacillus anthracis, the CDC anti-Protective Antigen (PA) IgG Enzyme-Linked Immunosorbent Assay (ELISA) was re-designed into a high throughput screening format. The following assay performance parameters were evaluated: goodness of fit (measured as the mean reference standard r2), accuracy (measured as percent error), precision (measured as coefficient of variance (CV)), lower limit of detection (LLOD), lower limit of quantification (LLOQ), dilutional linearity, diagnostic sensitivity (DSN) and diagnostic specificity (DSP). The paired sets of data for each sample were evaluated by Concordance Correlation Coefficient (CCC) analysis. The goodness of fit was 0.999; percent error between the expected and observed concentration for each sample ranged from −4.6% to 14.4%. The coefficient of variance ranged from 9.0% to 21.2%. The assay LLOQ was 2.6 μg/mL. The regression analysis results for dilutional linearity data were r2 = 0.952, slope = 1.02 and intercept = −0.03. CCC between assays was 0.974 for the median concentration of serum samples. The accuracy and precision components of CCC were 0.997 and 0.977, respectively. This high throughput screening assay is precise, accurate, sensitive and specific. Anti-PA IgG concentrations determined using two different assays proved high levels of agreement. The method will improve surge testing capability 18-fold from 4 to 72 sera per assay plate. PMID:27814939

Validation of high throughput screening of human sera for detection of anti-PA IgG by Enzyme-Linked Immunosorbent Assay (ELISA) as an emergency response to an anthrax incident.

PubMed

Semenova, Vera A; Steward-Clark, Evelene; Maniatis, Panagiotis; Epperson, Monica; Sabnis, Amit; Schiffer, Jarad

2017-01-01

To improve surge testing capability for a response to a release of Bacillus anthracis, the CDC anti-Protective Antigen (PA) IgG Enzyme-Linked Immunosorbent Assay (ELISA) was re-designed into a high throughput screening format. The following assay performance parameters were evaluated: goodness of fit (measured as the mean reference standard r 2 ), accuracy (measured as percent error), precision (measured as coefficient of variance (CV)), lower limit of detection (LLOD), lower limit of quantification (LLOQ), dilutional linearity, diagnostic sensitivity (DSN) and diagnostic specificity (DSP). The paired sets of data for each sample were evaluated by Concordance Correlation Coefficient (CCC) analysis. The goodness of fit was 0.999; percent error between the expected and observed concentration for each sample ranged from -4.6% to 14.4%. The coefficient of variance ranged from 9.0% to 21.2%. The assay LLOQ was 2.6 μg/mL. The regression analysis results for dilutional linearity data were r 2  = 0.952, slope = 1.02 and intercept = -0.03. CCC between assays was 0.974 for the median concentration of serum samples. The accuracy and precision components of CCC were 0.997 and 0.977, respectively. This high throughput screening assay is precise, accurate, sensitive and specific. Anti-PA IgG concentrations determined using two different assays proved high levels of agreement. The method will improve surge testing capability 18-fold from 4 to 72 sera per assay plate. Published by Elsevier Ltd.

High-throughput quantitation of amino acids in rat and mouse biological matrices using stable isotope labeling and UPLC-MS/MS analysis.

PubMed

Takach, Edward; O'Shea, Thomas; Liu, Hanlan

2014-08-01

Quantifying amino acids in biological matrices is typically performed using liquid chromatography (LC) coupled with fluorescent detection (FLD), requiring both derivatization and complete baseline separation of all amino acids. Due to its high specificity and sensitivity, the use of UPLC-MS/MS eliminates the derivatization step and allows for overlapping amino acid retention times thereby shortening the analysis time. Furthermore, combining UPLC-MS/MS with stable isotope labeling (e.g., isobaric tag for relative and absolute quantitation, i.e., iTRAQ) of amino acids enables quantitation while maintaining sensitivity, selectivity and speed of analysis. In this study, we report combining UPLC-MS/MS analysis with iTRAQ labeling of amino acids resulting in the elution and quantitation of 44 amino acids within 5 min demonstrating the speed and convenience of this assay over established approaches. This chromatographic analysis time represented a 5-fold improvement over the conventional HPLC-MS/MS method developed in our laboratory. In addition, the UPLC-MS/MS method demonstrated improvements in both specificity and sensitivity without loss of precision. In comparing UPLC-MS/MS and HPLC-MS/MS results of 32 detected amino acids, only 2 amino acids exhibited imprecision (RSD) >15% using UPLC-MS/MS, while 9 amino acids exhibited RSD >15% using HPLC-MS/MS. Evaluating intra- and inter-assay precision over 3 days, the quantitation range for 32 detected amino acids in rat plasma was 0.90-497 μM, with overall mean intra-day precision of less than 15% and mean inter-day precision of 12%. This UPLC-MS/MS assay was successfully implemented for the quantitative analysis of amino acids in rat and mouse plasma, along with mouse urine and tissue samples, resulting in the following concentration ranges: 0.98-431 μM in mouse plasma for 32 detected amino acids; 0.62-443 μM in rat plasma for 32 detected amino acids; 0.44-8590μM in mouse liver for 33 detected amino acids; 0.61-1241 μM in mouse kidney for 37 detected amino acids; and 1.39-1,681 μM in rat urine for 34 detected amino acids. The utility of the assay was further demonstrated by measuring and comparing plasma amino acid levels between pre-diabetic Zucker diabetic fatty rats (ZDF/Gmi fa/fa) and their lean littermates (ZDF/Gmi fa/?). Significant differences (P<0.001) in 9 amino acid concentrations were observed, with the majority ranging from a 2- to 5-fold increase in pre-diabetic ZDF rats on comparison with ZDF lean rats, consistent with previous literature reports. Copyright © 2014 Elsevier B.V. All rights reserved.

Environmental Effects for Gravitational-wave Astrophysics

NASA Astrophysics Data System (ADS)

Barausse, Enrico; Cardoso, Vitor; Pani, Paolo

2015-05-01

The upcoming detection of gravitational waves by terrestrial interferometers will usher in the era of gravitational-wave astronomy. This will be particularly true when space-based detectors will come of age and measure the mass and spin of massive black holes with exquisite precision and up to very high redshifts, thus allowing for better understanding of the symbiotic evolution of black holes with galaxies, and for high-precision tests of General Relativity in strong-field, highly dynamical regimes. Such ambitious goals require that astrophysical environmental pollution of gravitational-wave signals be constrained to negligible levels, so that neither detection nor estimation of the source parameters are significantly affected. Here, we consider the main sources for space-based detectors - the inspiral, merger and ringdown of massive black-hole binaries and extreme mass-ratio inspirals - and account for various effects on their gravitational waveforms, including electromagnetic fields, cosmological evolution, accretion disks, dark matter, “firewalls” and possible deviations from General Relativity. We discover that the black-hole quasinormal modes are sharply different in the presence of matter, but the ringdown signal observed by interferometers is typically unaffected. The effect of accretion disks and dark matter depends critically on their geometry and density profile, but is negligible for most sources, except for few special extreme mass-ratio inspirals. Electromagnetic fields and cosmological effects are always negligible. We finally explore the implications of our findings for proposed tests of General Relativity with gravitational waves, and conclude that environmental effects will not prevent the development of precision gravitational-wave astronomy.

Multiple-Baseline Detection of a Geostationary Satellite with the Navy Precision Optical Interferometer

DTIC Science & Technology

2015-01-01

Multiple-baseline detection of a geostationary satellite with the Navy Precision Optical Interferometer J. Thomas Armstronga, Ellyn K. Bainesa...observations of a geostationary satellite using the Navy Precision Optical Inter- ferometer (NPOI) during the glint season of March 2015. We succeeded in...the second night. These baseline lengths correspond to a resolution of ∼4 m at geostationary altitude. This is the first multiple-baseline

A new high-precision borehole-temperature logging system used at GISP2, Greenland, and Taylor Dome, Antarctica

USGS Publications Warehouse

Clow, G.D.; Saltus, R.W.; Waddington, E.D.

1996-01-01

We describe a high-precision (0.1-1.0 mK) borehole-temperature (BT) logging system developed at the United States Geological Survey (USGS) for use in remote polar regions. We discuss calibration, operational and data-processing procedures, and present an analysis of the measurement errors. The system is modular to facilitate calibration procedures and field repairs. By interchanging logging cables and temperature sensors, measurements can be made in either shallow air-filled boreholes or liquid-filled holes up to 7 km deep. Data can be acquired in either incremental or continuous-logging modes. The precision of data collected by the new logging system is high enough to detect and quantify various thermal effects at the milli-Kelvin level. To illustrate this capability, we present sample data from the 3 km deep borehole at GISP2, Greenland, and from a 130m deep air-filled hole at Taylor Dome, Antarctica. The precision of the processed GTSP2 continuous temperature logs is 0.25-0.34 mK, while the accuracy is estimated to be 4.5 mK. The effects of fluid convection and the dissipation of the thermal disturbance caused by drilling the borehole are clearly visible in the data. The precision of the incremental Taylor Dome measurements varies from 0.11 to 0.32mK, depending on the wind strength during the experiments. With this precision, we found that temperature fluctuations and multi-hour trends in the BT measurements correlate well with atmospheric-pressure changes.

Design of the NDUV detection circuit for the NO concentration of the vehicle exhaust emissions

NASA Astrophysics Data System (ADS)

Zhang, Kai; Zhang, Yujun; He, Ying; You, Kun; Gao, Yanwei; Chen, Chen; Liu, Guohua; He, Chungui; Lu, Yibing; Liu, Wenqing

2016-10-01

With the increasing number of vehicles, the harm from NO to the environment becomes more and more prominent. So the monitoring of the NO concentration of the vehicle exhaust emissions is very important to assess the emission levels. In this paper, the NO detection system designing for vehicle exhaust emissions based on the non-dispersive ultraviolet principle (NDUV) has been researched. The technical indexes of the two-way modulation UV signal detection circuit are discussed in detail. And then a precision detection circuit is designed, which is composed of a trans-impedance amplifier and a lock-in amplifier, with which the output of the UV photoelectric detector can be amplified to a suitable voltage range, and the DC noise of the pre-stage amplifier is effectively removed by the lock-in amplifier. An experimental system was set up to test the designed circuit. To ensure the consistency of the two channels, the method of exchange calibration was adopted in the test. It's drawn that the designed circuit is of high SNR, measuring accuracy and a large dynamic range from the test results. The NO concentration detection limit of vehicle emissions can reach 1ppm, and the detection precision is +/-15ppm.

Research on regional intrusion prevention and control system based on target tracking

NASA Astrophysics Data System (ADS)

Liu, Yanfei; Wang, Jieling; Jiang, Ke; He, Yanhui; Wu, Zhilin

2017-08-01

In view of the fact that China’s border is very long and the border prevention and control measures are single, we designed a regional intrusion prevention and control system which based on target-tracking. The system consists of four parts: solar panel, radar, electro-optical equipment, unmanned aerial vehicle and intelligent tracking platform. The solar panel provides independent power for the entire system. The radar detects the target in real time and realizes the high precision positioning of suspicious targets, then through the linkage of electro-optical equipment, it can achieve full-time automatic precise tracking of targets. When the target appears within the range of detection, the drone will be launched to continue the tracking. The system is mainly to realize the full time, full coverage, whole process integration and active realtime control of the border area.

NCLscan: accurate identification of non-co-linear transcripts (fusion, trans-splicing and circular RNA) with a good balance between sensitivity and precision.

PubMed

Chuang, Trees-Juen; Wu, Chan-Shuo; Chen, Chia-Ying; Hung, Li-Yuan; Chiang, Tai-Wei; Yang, Min-Yu

2016-02-18

Analysis of RNA-seq data often detects numerous 'non-co-linear' (NCL) transcripts, which comprised sequence segments that are topologically inconsistent with their corresponding DNA sequences in the reference genome. However, detection of NCL transcripts involves two major challenges: removal of false positives arising from alignment artifacts and discrimination between different types of NCL transcripts (trans-spliced, circular or fusion transcripts). Here, we developed a new NCL-transcript-detecting method ('NCLscan'), which utilized a stepwise alignment strategy to almost completely eliminate false calls (>98% precision) without sacrificing true positives, enabling NCLscan outperform 18 other publicly-available tools (including fusion- and circular-RNA-detecting tools) in terms of sensitivity and precision, regardless of the generation strategy of simulated dataset, type of intragenic or intergenic NCL event, read depth of coverage, read length or expression level of NCL transcript. With the high accuracy, NCLscan was applied to distinguishing between trans-spliced, circular and fusion transcripts on the basis of poly(A)- and nonpoly(A)-selected RNA-seq data. We showed that circular RNAs were expressed more ubiquitously, more abundantly and less cell type-specifically than trans-spliced and fusion transcripts. Our study thus describes a robust pipeline for the discovery of NCL transcripts, and sheds light on the fundamental biology of these non-canonical RNA events in human transcriptome. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

Automatic stent strut detection in intravascular OCT images using image processing and classification technique

NASA Astrophysics Data System (ADS)

Lu, Hong; Gargesha, Madhusudhana; Wang, Zhao; Chamie, Daniel; Attizani, Guilherme F.; Kanaya, Tomoaki; Ray, Soumya; Costa, Marco A.; Rollins, Andrew M.; Bezerra, Hiram G.; Wilson, David L.

2013-02-01

Intravascular OCT (iOCT) is an imaging modality with ideal resolution and contrast to provide accurate in vivo assessments of tissue healing following stent implantation. Our Cardiovascular Imaging Core Laboratory has served >20 international stent clinical trials with >2000 stents analyzed. Each stent requires 6-16hrs of manual analysis time and we are developing highly automated software to reduce this extreme effort. Using classification technique, physically meaningful image features, forward feature selection to limit overtraining, and leave-one-stent-out cross validation, we detected stent struts. To determine tissue coverage areas, we estimated stent "contours" by fitting detected struts and interpolation points from linearly interpolated tissue depths to a periodic cubic spline. Tissue coverage area was obtained by subtracting lumen area from the stent area. Detection was compared against manual analysis of 40 pullbacks. We obtained recall = 90+/-3% and precision = 89+/-6%. When taking struts deemed not bright enough for manual analysis into consideration, precision improved to 94+/-6%. This approached inter-observer variability (recall = 93%, precision = 96%). Differences in stent and tissue coverage areas are 0.12 +/- 0.41 mm2 and 0.09 +/- 0.42 mm2, respectively. We are developing software which will enable visualization, review, and editing of automated results, so as to provide a comprehensive stent analysis package. This should enable better and cheaper stent clinical trials, so that manufacturers can optimize the myriad of parameters (drug, coverage, bioresorbable versus metal, etc.) for stent design.

Measurement of super large radius optics in the detection of gravitational waves

NASA Astrophysics Data System (ADS)

Yang, Cheng; Han, Sen; Wu, Quanying; Liang, Binming; Hou, Changlun

2015-10-01

The existence of Gravitational Wave (GW) is one of the greatest predictions of Einstein's relative theory. It has played an important part in the radiation theory, black hole theory, space explore and so on. The GW detection has been an important aspect of modern physics. With the research proceeding further, there are still a lot of challenges existing in the interferometer which is the key instrument in GW detection especially the measurement of the super large radius optics. To solve this problem, one solution , Fizeau interference, for measuring the super large radius has been presented. We change the tradition that curved surface must be measured with a standard curved surface. We use a flat mirror as a reference flat and it can lower both the cost and the test requirement a lot. We select a concave mirror with the radius of 1600mm as a sample. After the precision measurement and analysis, the experimental results show that the relative error of radius is better than 3%, and it can fully meet the requirements of the measurement of super large radius optics. When calculating each pixel with standard cylinder, the edges are not sharp because of diffraction or some other reasons, we detect the edge and calculate the diameter of the cylinder automatically, and it can improve the precision a lot. In general, this method is simple, fast, non-traumatic, and highly precision, it can also provide us a new though in the measurement of super large radius optics.

Confirmation of radial velocity variability in Arcturus

NASA Technical Reports Server (NTRS)

Cochran, William D.

1988-01-01

The paper presents results of high-precision measurements of radial-velocity variations in Alpha Boo. Significant radial-velocity variability is detected well in excess of the random and systematic measurement errors. The radial velocity varies by an amount greater than 200 m/sec with a period of around 2 days.

Automatic Building Detection based on Supervised Classification using High Resolution Google Earth Images

NASA Astrophysics Data System (ADS)

Ghaffarian, S.; Ghaffarian, S.

2014-08-01

This paper presents a novel approach to detect the buildings by automization of the training area collecting stage for supervised classification. The method based on the fact that a 3d building structure should cast a shadow under suitable imaging conditions. Therefore, the methodology begins with the detection and masking out the shadow areas using luminance component of the LAB color space, which indicates the lightness of the image, and a novel double thresholding technique. Further, the training areas for supervised classification are selected by automatically determining a buffer zone on each building whose shadow is detected by using the shadow shape and the sun illumination direction. Thereafter, by calculating the statistic values of each buffer zone which is collected from the building areas the Improved Parallelepiped Supervised Classification is executed to detect the buildings. Standard deviation thresholding applied to the Parallelepiped classification method to improve its accuracy. Finally, simple morphological operations conducted for releasing the noises and increasing the accuracy of the results. The experiments were performed on set of high resolution Google Earth images. The performance of the proposed approach was assessed by comparing the results of the proposed approach with the reference data by using well-known quality measurements (Precision, Recall and F1-score) to evaluate the pixel-based and object-based performances of the proposed approach. Evaluation of the results illustrates that buildings detected from dense and suburban districts with divers characteristics and color combinations using our proposed method have 88.4 % and 853 % overall pixel-based and object-based precision performances, respectively.

Sampling animal sign in heterogeneous environments: how much is enough?

USGS Publications Warehouse

Holbrook, Joseph D.; Arkle, Robert S.; Rachlow, Janet L.; Vierling, Kerri T.; Pilliod, David S.

2015-01-01

Animal ecologists often use animal sign as a surrogate for direct observation of organisms, especially when species are secretive or difficult to observe. Spatial heterogeneity in arid environments makes it challenging to consistently detect and precisely characterize animal sign, which can bias estimates of animal abundance or habitat use. Piute ground squirrels (Urocitellus mollis) and Owyhee harvester ants (Pogonomyrmex salinus) live in arid environments and are fossorial, which can make them difficult to observe directly. Their relative abundance can be assessed using sign (i.e., burrows and nests). We implemented an over-sampling framework (i.e., recorded an excessive amount of information) with two observers to 1) identify a sampling intensity that balanced precision with our resource constraints, and 2) assess classification and detection of squirrel burrows and ant nests across vegetation conditions. We sampled 20 1-ha plots for ground squirrel burrows and ant nests using six 4 m × 100 m belt transects. Analyses of precision and sampling effort indicated that three belt transects covering 1200 m2 per ha provided sufficient precision, while minimizing effort. Regardless of vegetation conditions, counts by two observers were strongly correlated for ground squirrel burrows (r = 0.99, P < 0.001, df = 18; slope = 0.92) and harvester ant nests (r = 0.99, P < 0.001, df = 18; slope = 1.01) indicating observer consistency and perhaps high detection probability. These findings illustrate an approach for evaluating sampling designs in many ecological contexts.

Radial velocity detection of extra-solar planetary systems

NASA Technical Reports Server (NTRS)

Cochran, William D.

1991-01-01

The goal of this program was to detect planetary systems in orbit around other stars through the ultra high precision measurement of the orbital motion of the star around the star-planet barycenter. The survey of 33 nearby solar-type stars is the essential first step in understanding the overall problem of planet formation. The program will accumulate the necessary statistics to determine the frequency of planet formation as a function of stellar mass, age, and composition.

An update on TED gunshot detection system development status

NASA Astrophysics Data System (ADS)

Tidhar, Gil A.; Aphek, Ori; Gurovich, Martin

2009-05-01

In recent years the TED system has been under development, starting from new SWIR sensor technology, optics and real-time sensor technologies and following with complete system architecture as a soldier mounted optical gun shot detection system with high precision and imaging means. For the first time, the modules and the concept of operation of the system will be explained, with emphasis on new sensor-to-shooter capabilities. Actual field trial results will be shown.

Trojans and Plutinos as probes of planet building

NASA Astrophysics Data System (ADS)

Alexandersen, Mike; Gladman, B.; Kavelaars, J. J.; Petit, J.; Gwyn, S.; Greenstreet, S.

2013-10-01

Planetesimals formed during planet formation are the building blocks of giant planet cores; some are preserved as large trans-neptunian objects (TNOs). Previous work has shown steep power-law distributions for TNOs of diameters > 100 km. Recent results claim a dramatic roll-over or divot in the size distribution of Neptunian Trojans and scattering TNOs, with a significant lack of intermediate-size D<100 km planetesimals. One theoretical explanation for this is that planetesimals were born big, skipping the intermediate sizes, contrary to the classical understanding of planetesimal formation. Exploration of the TNO size distribution requires more precisely calibrated detections in order to improve statistics on these results. We have searched a 32 sq.deg. area near RA=2 hr to a r-band limiting magnitude of m_r=24.6 using the Canada-France-Hawaii Telescope. This coverage was near the Neptunian L4 region to maximise our detection rate, as this is where Trojans reside and where Plutinos (and several other resonant populations) come to perihelion. Our program successfully detected, tracked and characterized 77 TNOs and Centaurs for up to 17 months, giving us the high-quality orbits needed for precise modelling. Among our detections were one Uranian Trojan (see Alexandersen et al. 2013 & abstract by Greenstreet et al.), two Neptunian Trojans, 18 Plutinos and many other resonant objects. This meticulously calibrated survey and the high-quality orbits obtained for the detected objects allow us to create and test models of TNO size and orbital distributions. We test these models using a survey simulator, which simulates the detectability of model objects, accounting for the constraints and biases of our survey. Thus, we set precise constraints on the size and orbital distributions of the Neptunian Trojans, Plutinos and other resonant populations. We show that the Plutino inclination distribution is dynamically colder than found by the Canada-France Ecliptic Plane Survey. We also show that the Plutino size distribution cannot continue with the same slope for diameters < 100 km; a best-fit alternative will be presented. This research was supported by the Canadian National Sciences and Engineering Research Council.

High-precision measurements of cementless acetabular components using model-based RSA: an experimental study.

PubMed

Baad-Hansen, Thomas; Kold, Søren; Kaptein, Bart L; Søballe, Kjeld

2007-08-01

In RSA, tantalum markers attached to metal-backed acetabular cups are often difficult to detect on stereo radiographs due to the high density of the metal shell. This results in occlusion of the prosthesis markers and may lead to inconclusive migration results. Within the last few years, new software systems have been developed to solve this problem. We compared the precision of 3 RSA systems in migration analysis of the acetabular component. A hemispherical and a non-hemispherical acetabular component were mounted in a phantom. Both acetabular components underwent migration analyses with 3 different RSA systems: conventional RSA using tantalum markers, an RSA system using a hemispherical cup algorithm, and a novel model-based RSA system. We found narrow confidence intervals, indicating high precision of the conventional marker system and model-based RSA with regard to migration and rotation. The confidence intervals of conventional RSA and model-based RSA were narrower than those of the hemispherical cup algorithm-based system regarding cup migration and rotation. The model-based RSA software combines the precision of the conventional RSA software with the convenience of the hemispherical cup algorithm-based system. Based on our findings, we believe that these new tools offer an improvement in the measurement of acetabular component migration.

Location precision analysis of stereo thermal anti-sniper detection system

NASA Astrophysics Data System (ADS)

He, Yuqing; Lu, Ya; Zhang, Xiaoyan; Jin, Weiqi

2012-06-01

Anti-sniper detection devices are the urgent requirement in modern warfare. The precision of the anti-sniper detection system is especially important. This paper discusses the location precision analysis of the anti-sniper detection system based on the dual-thermal imaging system. It mainly discusses the following two aspects which produce the error: the digital quantitative effects of the camera; effect of estimating the coordinate of bullet trajectory according to the infrared images in the process of image matching. The formula of the error analysis is deduced according to the method of stereovision model and digital quantitative effects of the camera. From this, we can get the relationship of the detecting accuracy corresponding to the system's parameters. The analysis in this paper provides the theory basis for the error compensation algorithms which are put forward to improve the accuracy of 3D reconstruction of the bullet trajectory in the anti-sniper detection devices.

Sensitive and selective determination of methylenedioxylated amphetamines by high-performance liquid chromatography with fluorimetric detection.

PubMed

Sadeghipour, F; Veuthey, J L

1997-11-07

A rapid, sensitive and selective liquid chromatographic method with fluorimetric detection was developed for the separation and quantification of four methylenedioxylated amphetamines without interference of other drugs of abuse and common substances found in illicit tablets. The method was validated by examining linearity, precision and accuracy as well as detection and quantification limits. Methylenedioxylated amphetamines were quantified in eight tablets from illicit drug seizures and results were quantitatively compared to HPLC-UV analyses. To demonstrate the better sensitivity of the fluorimetric detection, methylenedioxylated amphetamines were analyzed in serum after a liquid-liquid extraction procedure and results were also compared to HPLC-UV analyses.

Technical note: Coupling infrared gas analysis and cavity ring down spectroscopy for autonomous, high-temporal-resolution measurements of DIC and δ13C-DIC

NASA Astrophysics Data System (ADS)

Call, Mitchell; Schulz, Kai G.; Carvalho, Matheus C.; Santos, Isaac R.; Maher, Damien T.

2017-03-01

A new approach to autonomously determine concentrations of dissolved inorganic carbon (DIC) and its carbon stable isotope ratio (δ13C-DIC) at high temporal resolution is presented. The simple method requires no customised design. Instead it uses two commercially available instruments currently used in aquatic carbon research. An inorganic carbon analyser utilising non-dispersive infrared detection (NDIR) is coupled to a Cavity Ring-down Spectrometer (CRDS) to determine DIC and δ13C-DIC based on the liberated CO2 from acidified aliquots of water. Using a small sample volume of 2 mL, the precision and accuracy of the new method was comparable to standard isotope ratio mass spectrometry (IRMS) methods. The system achieved a sampling resolution of 16 min, with a DIC precision of ±1.5 to 2 µmol kg-1 and δ13C-DIC precision of ±0.14 ‰ for concentrations spanning 1000 to 3600 µmol kg-1. Accuracy of 0.1 ± 0.06 ‰ for δ13C-DIC based on DIC concentrations ranging from 2000 to 2230 µmol kg-1 was achieved during a laboratory-based algal bloom experiment. The high precision data that can be autonomously obtained by the system should enable complex carbonate system questions to be explored in aquatic sciences using high-temporal-resolution observations.

Study on on-machine defects measuring system on high power laser optical elements

NASA Astrophysics Data System (ADS)

Luo, Chi; Shi, Feng; Lin, Zhifan; Zhang, Tong; Wang, Guilin

2017-10-01

The influence of surface defects on high power laser optical elements will cause some harm to the performances of imaging system, including the energy consumption and the damage of film layer. To further increase surface defects on high power laser optical element, on-machine defects measuring system was investigated. Firstly, the selection and design are completed by the working condition analysis of the on-machine defects detection system. By designing on processing algorithms to realize the classification recognition and evaluation of surface defects. The calibration experiment of the scratch was done by using the self-made standard alignment plate. Finally, the detection and evaluation of surface defects of large diameter semi-cylindrical silicon mirror are realized. The calibration results show that the size deviation is less than 4% that meet the precision requirement of the detection of the defects. Through the detection of images the on-machine defects detection system can realize the accurate identification of surface defects.

Validation of a method to detect cocaine and its metabolites in nails by gas chromatography-mass spectrometry.

PubMed

Valente-Campos, Simone; Yonamine, Mauricio; de Moraes Moreau, Regina Lucia; Silva, Ovandir Alves

2006-06-02

The objective of the present work was to compare previously published methods and provide validation data to detect simultaneously cocaine (COC), benzoylecgonine (BE) and norcocaine (NCOC) in nail. Finger and toenail samples (5mg) were cut in very small pieces and submitted to an initial procedure for external decontamination. Methanol (3 ml) was used to release analytes from the matrix. A cleanup step was performed simultaneously by solid-phase extraction (SPE) and the residue was derivatized with pentafluoropropionic anhydride/pentafluoropropanol (PFPA/PFP). Gas chromatography-mass spectrometry (GC-MS) was used to detect the analytes in selected ion monitoring mode (SIM). Confidence parameters of validation of the method were: recovery, intra- and inter-assay precision, as well as limit of detection (LOD) of the analytes. The limits of detection were: 3.5 ng/mg for NCOC and 3.0 ng/mg for COC and BE. Good intra-assay precision was observed for all detected substances (coefficient of variation (CV)<11%). The inter-assay precision for norcocaine and benzoylecgonine were <4%. For intra- and inter-assay precision deuterated internal standards were used. Toenail and fingernail samples from eight declared cocaine users were submitted to the validated method.

RADIAL VELOCITY VARIABILITY OF FIELD BROWN DWARFS

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

Prato, L.; Mace, G. N.; Rice, E. L.

2015-07-20

We present paper six of the NIRSPEC Brown Dwarf Spectroscopic Survey, an analysis of multi-epoch, high-resolution (R ∼ 20,000) spectra of 25 field dwarf systems (3 late-type M dwarfs, 16 L dwarfs, and 6 T dwarfs) taken with the NIRSPEC infrared spectrograph at the W. M. Keck Observatory. With a radial velocity (RV) precision of ∼2 km s{sup −1}, we are sensitive to brown dwarf companions in orbits with periods of a few years or less given a mass ratio of 0.5 or greater. We do not detect any spectroscopic binary brown dwarfs in the sample. Given our target properties,more » and the frequency and cadence of observations, we use a Monte Carlo simulation to determine the detection probability of our sample. Even with a null detection result, our 1σ upper limit for very low mass binary frequency is 18%. Our targets included seven known, wide brown dwarf binary systems. No significant RV variability was measured in our multi-epoch observations of these systems, even for those pairs for which our data spanned a significant fraction of the orbital period. Specialized techniques are required to reach the high precisions sensitive to motion in orbits of very low-mass systems. For eight objects, including six T dwarfs, we present the first published high-resolution spectra, many with high signal to noise, that will provide valuable comparison data for models of brown dwarf atmospheres.« less

A Highly Flexible, Automated System Providing Reliable Sample Preparation in Element- and Structure-Specific Measurements.

PubMed

Vorberg, Ellen; Fleischer, Heidi; Junginger, Steffen; Liu, Hui; Stoll, Norbert; Thurow, Kerstin

2016-10-01

Life science areas require specific sample pretreatment to increase the concentration of the analytes and/or to convert the analytes into an appropriate form for the detection and separation systems. Various workstations are commercially available, allowing for automated biological sample pretreatment. Nevertheless, due to the required temperature, pressure, and volume conditions in typical element and structure-specific measurements, automated platforms are not suitable for analytical processes. Thus, the purpose of the presented investigation was the design, realization, and evaluation of an automated system ensuring high-precision sample preparation for a variety of analytical measurements. The developed system has to enable system adaption and high performance flexibility. Furthermore, the system has to be capable of dealing with the wide range of required vessels simultaneously, allowing for less cost and time-consuming process steps. However, the system's functionality has been confirmed in various validation sequences. Using element-specific measurements, the automated system was up to 25% more precise compared to the manual procedure and as precise as the manual procedure using structure-specific measurements. © 2015 Society for Laboratory Automation and Screening.

Integrated multi-ISE arrays with improved sensitivity, accuracy and precision

NASA Astrophysics Data System (ADS)

Wang, Chunling; Yuan, Hongyan; Duan, Zhijuan; Xiao, Dan

2017-03-01

Increasing use of ion-selective electrodes (ISEs) in the biological and environmental fields has generated demand for high-sensitivity ISEs. However, improving the sensitivities of ISEs remains a challenge because of the limit of the Nernstian slope (59.2/n mV). Here, we present a universal ion detection method using an electronic integrated multi-electrode system (EIMES) that bypasses the Nernstian slope limit of 59.2/n mV, thereby enabling substantial enhancement of the sensitivity of ISEs. The results reveal that the response slope is greatly increased from 57.2 to 1711.3 mV, 57.3 to 564.7 mV and 57.7 to 576.2 mV by electronic integrated 30 Cl- electrodes, 10 F- electrodes and 10 glass pH electrodes, respectively. Thus, a tiny change in the ion concentration can be monitored, and correspondingly, the accuracy and precision are substantially improved. The EIMES is suited for all types of potentiometric sensors and may pave the way for monitoring of various ions with high accuracy and precision because of its high sensitivity.

Precision Isotope Shift Measurements in Calcium Ions Using Quantum Logic Detection Schemes.

PubMed

Gebert, Florian; Wan, Yong; Wolf, Fabian; Angstmann, Christopher N; Berengut, Julian C; Schmidt, Piet O

2015-07-31

We demonstrate an efficient high-precision optical spectroscopy technique for single trapped ions with nonclosed transitions. In a double-shelving technique, the absorption of a single photon is first amplified to several phonons of a normal motional mode shared with a cotrapped cooling ion of a different species, before being further amplified to thousands of fluorescence photons emitted by the cooling ion using the standard electron shelving technique. We employ this extension of the photon recoil spectroscopy technique to perform the first high precision absolute frequency measurement of the 2D(3/2)→2P(1/2) transition in calcium, resulting in a transition frequency of f=346 000 234 867(96)  kHz. Furthermore, we determine the isotope shift of this transition and the 2S(1/2)→2P(1/2) transition for 42Ca+, 44Ca+, and 48Ca+ ions relative to 40Ca+ with an accuracy below 100 kHz. Improved field and mass shift constants of these transitions as well as changes in mean square nuclear charge radii are extracted from this high resolution data.

Trueness, Precision, and Detectability for Sampling and Analysis of Organic Species in Airborne Particulate Matter

EPA Science Inventory

Recovery. precision, limits of detection and quantitation, blank levels, calibration linearity, and agreement with certified reference materials were determined for two classes of organic components of airborne particulate matter, polycyclic aromatic hydrocarbons and hopanes usin...

High-precision terahertz frequency modulated continuous wave imaging method using continuous wavelet transform

NASA Astrophysics Data System (ADS)

Zhou, Yu; Wang, Tianyi; Dai, Bing; Li, Wenjun; Wang, Wei; You, Chengwu; Wang, Kejia; Liu, Jinsong; Wang, Shenglie; Yang, Zhengang

2018-02-01

Inspired by the extensive application of terahertz (THz) imaging technologies in the field of aerospace, we exploit a THz frequency modulated continuous-wave imaging method with continuous wavelet transform (CWT) algorithm to detect a multilayer heat shield made of special materials. This method uses the frequency modulation continuous-wave system to catch the reflected THz signal and then process the image data by the CWT with different basis functions. By calculating the sizes of the defects area in the final images and then comparing the results with real samples, a practical high-precision THz imaging method is demonstrated. Our method can be an effective tool for the THz nondestructive testing of composites, drugs, and some cultural heritages.

Creation of the precision magnetic spectrometer SCAN-3

NASA Astrophysics Data System (ADS)

Afanasiev, S. V.; Anisimov, Yu. S.; Baldin, A. A.; Berlev, A. I.; Dryablov, D. K.; Dubinchik, B. V.; Elishev, A. F.; Fateev, O. V.; Igamkulov, Z. A.; Krechetov, Yu. F.; Kudashkin, I. V.; Kuznechov, S. N.; Malakhov, A. I.; Smirnov, V. A.; Shimansky, S. S.; Kliman, J.; Matousek, V.; Gmutsa, S.; Turzo, I.; Cruceru, I.; Cruceru, M.; Constantin, F.; Niolescu, G.; Ciolacu, L.; Paraipan, M.; Vokál, S.; Vrláková, J.; Baskov, V. A.; Lebedev, A. I.; L'vov, A. I.; Pavlyuchenko, L. N.; Polyansky, V. V.; Rzhanov, E. V.; Sidorin, S. S.; Sokol, G. A.; Glavanakov, I. V.; Tabachenko, A. N.; Jomurodov, D. M.; Bekmirzaev, R. N.; Ibadov, R. M.; Sultanov, M. U.

2017-03-01

The new JINR project [1] is aimed at studies of highly excited nuclear matter created in nuclei by a high-energy deuteron beam. The matter is studied through observation of its particular decay products - pairs of energetic particles with a wide opening angle, close to 180°. The new precision hybrid magnetic spectrometer SCAN-3 is to be built for detecting charged (π±, K±, p) and neutral (n) particles produced at the JINR Nuclotron internal target in dA collisions. One of the main and complex tasks is a study of low-energy ηA interaction and a search for η-bound states (η-mesic nuclei). Basic elements of the spectrometer and its characteristics are discussed in the article.

Radial Velocity Detection of Extra-Solar Planetary Systems

NASA Technical Reports Server (NTRS)

Cochran, William D.

2004-01-01

This NASA Origins Program grant supported four closely related research programs at The University of Texas at Austin: 1) The McDonald Observatory Planetary Search (MOPS) Program, using the McDonald Observatory 2.7m Harlan Smith telescope and its 2dcoude spectrometer, 2) A high-precision radial-velocity survey of Hyades dwarfs, using the Keck telescope and its HIRES spectrograph, 3) A program at McDonald Observatory to obtain spectra of the parent stars of planetary systems at R = 210,000, and 4) the start of high precision radial velocity surveys using the Hobby-Eberly Telescope. The most important results from NASA support of these research programs are described. A list of all papers published under support of this grant is included at the end.

Laser-ranging long-baseline differential atom interferometers for space

NASA Astrophysics Data System (ADS)

Chiow, Sheng-wey; Williams, Jason; Yu, Nan

2015-12-01

High-sensitivity differential atom interferometers (AIs) are promising for precision measurements in science frontiers in space, including gravity-field mapping for Earth science studies and gravitational wave detection. Difficulties associated with implementing long-baseline differential AIs have previously included the need for a high optical power, large differential Doppler shifts, and narrow dynamic range. We propose a configuration of twin AIs connected by a laser-ranging interferometer (LRI-AI) to provide precise information of the displacements between the two AI reference mirrors and also to phase-lock the two independent interferometer lasers over long distances, thereby drastically improving the practical feasibility of long-baseline differential AI measurements. We show that a properly implemented LRI-AI can achieve equivalent functionality to the conventional differential AI measurement configuration.

Development of mass spectrometric techniques applicable to the search for organic matter in the lunar crust

NASA Technical Reports Server (NTRS)

Biemann, K.

1973-01-01

Data processing techniques were developed to measure with high precision and sensitivity the line spectra produced by a high resolution mass spectrometer. The most important aspect of this phase was the interfacing of a modified precision microphotometer-comparator with a computer and the improvement of existing software to serve the special needs of the investigation of lunar samples. In addition, a gas-chromatograph mass spectrometer system was interfaced with the same computer to allow continuous recording of mass spectra on a gas chromatographic effluent and efficient evaluation of the resulting data. These techniques were then used to detect and identify organic compounds present in the samples returned by the Apollo 11 and 12 missions.

Balancing precision and risk: should multiple detection methods be analyzed separately in N-mixture models?

USGS Publications Warehouse

Graves, Tabitha A.; Royle, J. Andrew; Kendall, Katherine C.; Beier, Paul; Stetz, Jeffrey B.; Macleod, Amy C.

2012-01-01

Using multiple detection methods can increase the number, kind, and distribution of individuals sampled, which may increase accuracy and precision and reduce cost of population abundance estimates. However, when variables influencing abundance are of interest, if individuals detected via different methods are influenced by the landscape differently, separate analysis of multiple detection methods may be more appropriate. We evaluated the effects of combining two detection methods on the identification of variables important to local abundance using detections of grizzly bears with hair traps (systematic) and bear rubs (opportunistic). We used hierarchical abundance models (N-mixture models) with separate model components for each detection method. If both methods sample the same population, the use of either data set alone should (1) lead to the selection of the same variables as important and (2) provide similar estimates of relative local abundance. We hypothesized that the inclusion of 2 detection methods versus either method alone should (3) yield more support for variables identified in single method analyses (i.e. fewer variables and models with greater weight), and (4) improve precision of covariate estimates for variables selected in both separate and combined analyses because sample size is larger. As expected, joint analysis of both methods increased precision as well as certainty in variable and model selection. However, the single-method analyses identified different variables and the resulting predicted abundances had different spatial distributions. We recommend comparing single-method and jointly modeled results to identify the presence of individual heterogeneity between detection methods in N-mixture models, along with consideration of detection probabilities, correlations among variables, and tolerance to risk of failing to identify variables important to a subset of the population. The benefits of increased precision should be weighed against those risks. The analysis framework presented here will be useful for other species exhibiting heterogeneity by detection method.

High-Speed Scanning Interferometer Using CMOS Image Sensor and FPGA Based on Multifrequency Phase-Tracking Detection

NASA Technical Reports Server (NTRS)

Ohara, Tetsuo

2012-01-01

A sub-aperture stitching optical interferometer can provide a cost-effective solution for an in situ metrology tool for large optics; however, the currently available technologies are not suitable for high-speed and real-time continuous scan. NanoWave s SPPE (Scanning Probe Position Encoder) has been proven to exhibit excellent stability and sub-nanometer precision with a large dynamic range. This same technology can transform many optical interferometers into real-time subnanometer precision tools with only minor modification. The proposed field-programmable gate array (FPGA) signal processing concept, coupled with a new-generation, high-speed, mega-pixel CMOS (complementary metal-oxide semiconductor) image sensor, enables high speed (>1 m/s) and real-time continuous surface profiling that is insensitive to variation of pixel sensitivity and/or optical transmission/reflection. This is especially useful for large optics surface profiling.

Multi-dynamic range compressional wave detection using optical-frequency comb

NASA Astrophysics Data System (ADS)

Minamikawa, Takeo; Masuoka, Takashi; Oe, Ryo; Nakajima, Yoshiaki; Yamaoka, Yoshihisa; Minoshima, Kaoru; Yasui, Takeshi

2018-02-01

Compressional wave detection is useful means for health monitoring of building, detection of abnormal vibration of moving objects, defect evaluation, and biomedical imaging such as echography and photoacoustic imaging. The frequency of the compressional wave is varied from quasi-static to a few tens of megahertz depending on applications. Since the dynamic range of general compressional wave detectors is limited, we need to choose a proper compressional wave detector depending on applications. For the compressional wave detection with wide dynamic range, two or more detectors with different detection ranges is required. However, these detectors with different detection ranges generally has different accuracy and precision, disabling the seamless detection over these detection ranges. In this study, we proposed a compressional wave detector employing optical frequency comb (OFC). The compressional wave was sensed with a part of an OFC cavity, being encoded into OFC. The spectrally encoded OFC was converted to radio-frequency by the frequency link nature of OFC. The compressional wave-encoded radio-frequency can therefore be directly measured with a high-speed photodetector. To enhance the dynamic range of the compressional wave detection, we developed a cavityfeedback-based system and a phase-sensitive detection system, both of which the accuracy and precision are coherently linked to these of the OFC. We provided a proof-of-principle demonstration of the detection of compressional wave from quasi-static to ultrasound wave by using the OFC-based compressional wave sensor. Our proposed approach will serve as a unique and powerful tool for detecting compressional wave versatile applications in the future.

A portable, stable and precise laser differential refractometer

NASA Astrophysics Data System (ADS)

Gong, Xiangjun; Ngai, To; Wu, Chi

2013-11-01

In this work, we present a portable laser differential refractometer with real-time detection and high precision based on the Snell's law and a 2f-2f optical design. The 2f-2f configuration solves a traditional position drifting problem of the laser beam and enhances the signal stability, where a small pinhole is illuminated by the laser light and imaged to the detector by lens placed in the middle between the detector and the pinhole. However, it also leads to a larger dimension of the instrument, limiting its applications and its sensitivity that is proportional to the optical path. Therefore, for a portable device on the basis of the 2f-2f design, a combination of a mirror and a lens was developed to minimize the optical path without affecting the 2f-2f design. Our simple and compact design reaches a resolution of 10-6 refractive index units (RIU). Moreover, the dimension of such a modified differential refractometer is significantly reduced to be portable. Owing to its real-time detection speed and high precision, this newly developed refractometer is particularly attractive when it is used as an independent and ultra-sensitive detector in many research and industrial applications wherein there is a time-dependent concentration change, e.g., the concentration determination, quality control, and study of kinetic processes in solution, including adsorption, sedimentation, and dissolution, to name few but not limited.

Validation of an analytical method for simultaneous high-precision measurements of greenhouse gas emissions from wastewater treatment plants using a gas chromatography-barrier discharge detector system.

PubMed

Pascale, Raffaella; Caivano, Marianna; Buchicchio, Alessandro; Mancini, Ignazio M; Bianco, Giuliana; Caniani, Donatella

2017-01-13

Wastewater treatment plants (WWTPs) emit CO 2 and N 2 O, which may lead to climate change and global warming. Over the last few years, awareness of greenhouse gas (GHG) emissions from WWTPs has increased. Moreover, the development of valid, reliable, and high-throughput analytical methods for simultaneous gas analysis is an essential requirement for environmental applications. In the present study, an analytical method based on a gas chromatograph (GC) equipped with a barrier ionization discharge (BID) detector was developed for the first time. This new method simultaneously analyses CO 2 and N 2 O and has a precision, measured in terms of relative standard of variation RSD%, equal to or less than 6.6% and 5.1%, respectively. The method's detection limits are 5.3ppm v for CO 2 and 62.0ppb v for N 2 O. The method's selectivity, linearity, accuracy, repeatability, intermediate precision, limit of detection and limit of quantification were good at trace concentration levels. After validation, the method was applied to a real case of N 2 O and CO 2 emissions from a WWTP, confirming its suitability as a standard procedure for simultaneous GHG analysis in environmental samples containing CO 2 levels less than 12,000mg/L. Copyright © 2016 Elsevier B.V. All rights reserved.

Crop Phenology Detection Using High Spatio-Temporal Resolution Data Fused from SPOT5 and MODIS Products

PubMed Central

Zheng, Yang; Wu, Bingfang; Zhang, Miao; Zeng, Hongwei

2016-01-01

Timely and efficient monitoring of crop phenology at a high spatial resolution are crucial for the precise and effective management of agriculture. Recently, satellite-derived vegetation indices (VIs), such as the Normalized Difference Vegetation Index (NDVI), have been widely used for the phenology detection of terrestrial ecosystems. In this paper, a framework is proposed to detect crop phenology using high spatio-temporal resolution data fused from Systeme Probatoire d'Observation de la Tarre5 (SPOT5) and Moderate Resolution Imaging Spectroradiometer (MODIS) images. The framework consists of a data fusion method to produce a synthetic NDVI dataset at SPOT5’s spatial resolution and at MODIS’s temporal resolution and a phenology extraction algorithm based on NDVI time-series analysis. The feasibility of our phenology detection approach was evaluated at the county scale in Shandong Province, China. The results show that (1) the Spatial and Temporal Adaptive Reflectance Fusion Model (STARFM) algorithm can accurately blend SPOT5 and MODIS NDVI, with an R2 of greater than 0.69 and an root mean square error (RMSE) of less than 0.11 between the predicted and referenced data; and that (2) the estimated phenology parameters, such as the start and end of season (SOS and EOS), were closely correlated with the field-observed data with an R2 of the SOS ranging from 0.68 to 0.86 and with an R2 of the EOS ranging from 0.72 to 0.79. Our research provides a reliable approach for crop phenology mapping in areas with high fragmented farmland, which is meaningful for the implementation of precision agriculture. PMID:27973404

Crop Phenology Detection Using High Spatio-Temporal Resolution Data Fused from SPOT5 and MODIS Products.

PubMed

Zheng, Yang; Wu, Bingfang; Zhang, Miao; Zeng, Hongwei

2016-12-10

Timely and efficient monitoring of crop phenology at a high spatial resolution are crucial for the precise and effective management of agriculture. Recently, satellite-derived vegetation indices (VIs), such as the Normalized Difference Vegetation Index (NDVI), have been widely used for the phenology detection of terrestrial ecosystems. In this paper, a framework is proposed to detect crop phenology using high spatio-temporal resolution data fused from Systeme Probatoire d'Observation de la Tarre5 (SPOT5) and Moderate Resolution Imaging Spectroradiometer (MODIS) images. The framework consists of a data fusion method to produce a synthetic NDVI dataset at SPOT5's spatial resolution and at MODIS's temporal resolution and a phenology extraction algorithm based on NDVI time-series analysis. The feasibility of our phenology detection approach was evaluated at the county scale in Shandong Province, China. The results show that (1) the Spatial and Temporal Adaptive Reflectance Fusion Model (STARFM) algorithm can accurately blend SPOT5 and MODIS NDVI, with an R ² of greater than 0.69 and an root mean square error (RMSE) of less than 0.11 between the predicted and referenced data; and that (2) the estimated phenology parameters, such as the start and end of season (SOS and EOS), were closely correlated with the field-observed data with an R ² of the SOS ranging from 0.68 to 0.86 and with an R ² of the EOS ranging from 0.72 to 0.79. Our research provides a reliable approach for crop phenology mapping in areas with high fragmented farmland, which is meaningful for the implementation of precision agriculture.

Observing exoplanet populations with high-precision astrometry

NASA Astrophysics Data System (ADS)

Sahlmann, Johannes

2012-06-01

This thesis deals with the application of the astrometry technique, consisting in measuring the position of a star in the plane of the sky, for the discovery and characterisation of extra-solar planets. It is feasible only with a very high measurement precision, which motivates the use of space observatories, the development of new ground-based astronomical instrumentation and of innovative data analysis methods: The study of Sun-like stars with substellar companions using CORALIE radial velocities and HIPPARCOS astrometry leads to the determination of the frequency of close brown dwarf companions and to the discovery of a dividing line between massive planets and brown dwarf companions; An observation campaign employing optical imaging with a very large telescope demonstrates sufficient astrometric precision to detect planets around ultra-cool dwarf stars and the first results of the survey are presented; Finally, the design and initial astrometric performance of PRIMA, ! a new dual-feed near-infrared interferometric observing facility for relative astrometry is presented.

Automated and sensitive method for the determination of formoterol in human plasma by high-performance liquid chromatography and electrochemical detection.

PubMed

Campestrini, J; Lecaillon, J B; Godbillon, J

1997-12-19

An automated high-performance liquid chromatography (HPLC) method for the determination of formoterol in human plasma with improved sensitivity has been developed and validated. Formoterol and CGP 47086, the internal standard, were extracted from plasma (1 ml) using a cation-exchange solid-phase extraction (SPE) cartridge. The compounds were eluted with pH 6 buffer solution-methanol (70:30, v/v) and the eluate was further diluted with water. An aliquot of the extract solution was injected and analyzed by HPLC. The extraction, dilution, injection and chromatographic analysis were combined and automated using the automate (ASPEC) system. The chromatographic separations were achieved on a 5 microm, Hypersil ODS analytical column (200 mm x 3 mm I.D.), using (pH 6 phosphate buffer, 0.035 M + 20 mg/l EDTA)-MeOH-CH3CN (70:25:5, v/v/v) as the mobile phase at a flow-rate of 0.4 ml/min. The analytes were detected with electrochemical detection at an operating potential of +0.63 V. Intra-day accuracy and precision were assessed from the relative recoveries of calibration/quality control plasma samples in the concentration range of 7.14 to 238 pmol/l of formoterol base. The accuracy over the entire concentration range varied from 81 to 105%, and the precision (C.V.) ranged from 3 to 14%. Inter-day accuracy and precision were assessed in the concentration range of 11.9 to 238 pmol/l of formoterol base in plasma. The accuracy over the entire concentration range varied from 98 to 109%, and precision ranged from 8 to 19%. At the limit of quantitation (LOQ) of 11.9 pmol/l for inter-day measurements, the recovery value was 109% and C.V. was 19%. As shown from intra-day accuracy and precision results, favorable conditions (a newly used column, a newly washed detector cell and moderate residual cell current level) allowed us to reach a LOQ of 7.14 pmol/l of formoterol base (3 pg/ml of formoterol fumarate dihydrate). Improvement of the limit of detection by a factor of about 10 was reached as compared to the previously described methods. The method has been applied for quantifying formoterol in plasma after 120 microg drug inhalation to volunteers. Formoterol was still measurable at 24 h post-dosing in most subjects and a slow elimination of formoterol from plasma beyond 6-8 h after inhalation was demonstrated for the first time thanks to the sensitivity of the method.

High-performance time-resolved fluorescence by direct waveform recording.

PubMed

Muretta, Joseph M; Kyrychenko, Alexander; Ladokhin, Alexey S; Kast, David J; Gillispie, Gregory D; Thomas, David D

2010-10-01

We describe a high-performance time-resolved fluorescence (HPTRF) spectrometer that dramatically increases the rate at which precise and accurate subnanosecond-resolved fluorescence emission waveforms can be acquired in response to pulsed excitation. The key features of this instrument are an intense (1 μJ/pulse), high-repetition rate (10 kHz), and short (1 ns full width at half maximum) laser excitation source and a transient digitizer (0.125 ns per time point) that records a complete and accurate fluorescence decay curve for every laser pulse. For a typical fluorescent sample containing a few nanomoles of dye, a waveform with a signal/noise of about 100 can be acquired in response to a single laser pulse every 0.1 ms, at least 10(5) times faster than the conventional method of time-correlated single photon counting, with equal accuracy and precision in lifetime determination for lifetimes as short as 100 ps. Using standard single-lifetime samples, the detected signals are extremely reproducible, with waveform precision and linearity to within 1% error for single-pulse experiments. Waveforms acquired in 0.1 s (1000 pulses) with the HPTRF instrument were of sufficient precision to analyze two samples having different lifetimes, resolving minor components with high accuracy with respect to both lifetime and mole fraction. The instrument makes possible a new class of high-throughput time-resolved fluorescence experiments that should be especially powerful for biological applications, including transient kinetics, multidimensional fluorescence, and microplate formats.

Enhanced trigger for the NIFFTE fissionTPC in presence of high-rate alpha backgrounds

NASA Astrophysics Data System (ADS)

Bundgaard, Jeremy; Niffte Collaboration

2015-10-01

Nuclear physics and nuclear energy communities call for new, high precision measurements to improve existing fission models and design next generation reactors. The Neutron Induced Fission Fragment Tracking experiment (NIFFTE) has developed the fission Time Projection Chamber (fissionTPC) to measure neutron induced fission with unrivaled precision. The fissionTPC is annually deployed to the Weapons Neutron Research facility at Los Alamos Neutron Science Center where it operates with a neutron beam passing axially through the drift volume, irradiating heavy actinide targets to induce fission. The fissionTPC was developed at the Lawrence Livermore National Laboratory's TPC lab, where it measures spontaneous fission from radioactive sources to characterize detector response, improve performance, and evolve the design. To measure 244Cm, we've developed a fission trigger to reduce the data rate from alpha tracks while maintaining a high fission detection efficiency. In beam, alphas from 239Pu are a large background when detecting fission fragments; implementing the fission trigger will greatly reduce this background. The implementation of the cathode fission trigger in the fissionTPC will be presented along with a detailed study of its efficiency.

High Energy 2-Micron Solid-State Laser Transmitter for NASA's Airborne CO2 Measurements

NASA Technical Reports Server (NTRS)

Singh, Upendra N.; Yu, Jirong; Petros, Mulugeta; Bai, Yingxin

2012-01-01

A 2-micron pulsed, Integrated Path Differential Absorption (IPDA) lidar instrument for ground and airborne atmospheric CO2 concentration measurements via direct detection method is being developed at NASA Langley Research Center. This instrument will provide an alternate approach to measure atmospheric CO2 concentrations with significant advantages. A high energy pulsed approach provides high-precision measurement capability by having high signal-to-noise level and unambiguously eliminates the contamination from aerosols and clouds that can bias the IPDA measurement.

Nanoparticle imaging probes for molecular imaging with computed tomography and application to cancer imaging

NASA Astrophysics Data System (ADS)

Roeder, Ryan K.; Curtis, Tyler E.; Nallathamby, Prakash D.; Irimata, Lisa E.; McGinnity, Tracie L.; Cole, Lisa E.; Vargo-Gogola, Tracy; Cowden Dahl, Karen D.

2017-03-01

Precision imaging is needed to realize precision medicine in cancer detection and treatment. Molecular imaging offers the ability to target and identify tumors, associated abnormalities, and specific cell populations with overexpressed receptors. Nuclear imaging and radionuclide probes provide high sensitivity but subject the patient to a high radiation dose and provide limited spatiotemporal information, requiring combined computed tomography (CT) for anatomic imaging. Therefore, nanoparticle contrast agents have been designed to enable molecular imaging and improve detection in CT alone. Core-shell nanoparticles provide a powerful platform for designing tailored imaging probes. The composition of the core is chosen for enabling strong X-ray contrast, multi-agent imaging with photon-counting spectral CT, and multimodal imaging. A silica shell is used for protective, biocompatible encapsulation of the core composition, volume-loading fluorophores or radionuclides for multimodal imaging, and facile surface functionalization with antibodies or small molecules for targeted delivery. Multi-agent (k-edge) imaging and quantitative molecular imaging with spectral CT was demonstrated using current clinical agents (iodine and BaSO4) and a proposed spectral library of contrast agents (Gd2O3, HfO2, and Au). Bisphosphonate-functionalized Au nanoparticles were demonstrated to enhance sensitivity and specificity for the detection of breast microcalcifications by conventional radiography and CT in both normal and dense mammary tissue using murine models. Moreover, photon-counting spectral CT enabled quantitative material decomposition of the Au and calcium signals. Immunoconjugated Au@SiO2 nanoparticles enabled highly-specific targeting of CD133+ ovarian cancer stem cells for contrast-enhanced detection in model tumors.

Simple determination of L-hydroxyproline in idiopathic pulmonary fibrosis lung tissues of rats using non-extractive high-performance liquid chromatography coupled with fluorescence detection after pre-column derivatization with novel synthetic 9-acetylimidazol-carbazole.

PubMed

Ren, Yan; Zhao, Juanjuan; Shi, Yanan; Chen, Caiyun; Chen, Xiangming; Lv, Changjun

2017-08-05

L-Hydroxyproline (L-Hyp) is an important biomarker for idiopathic pulmonary fibrosis (IPF). The quantitative methods based on high-performance liquid chromatography coupled with fluorescence detection after pre-column derivatization typically requires complicated derivatization conditions and obtains unstable derivatives. Here, a novel derivatization reagent, 9-acetylimidazol-carbazole, was synthesized for the first time to efficiently and rapidly label the amino groups of L-Hyp. The high-performance liquid chromatography method with pre-column derivatization was performed on an Agilent ZORBAX SB-C 18 column (4.6×250mm, 5μm). The product was measured using fluorescence detection at excitation and emission wavelengths of 232 and 370nm, respectively. The method was validated in specificity, linearity, limit of detection (66.7 fmol), limit of quantification (333.3fmol), intra-day precision (0.75%), inter-day precision (3.82%), stability (3.15%), and recovery (90.7-109.4%). The validated method was successfully applied to the determination of L-Hyp in the lung tissues of healthy and IPF rats. The results showed that the concentration of L-Hyp (3.64mg/g) in the IPF model was significantly higher than the concentration (2.33mg/g) in the healthy control group with P<0.01. This is a new method for the determination of L-Hyp and can be used for other amino acid-related studies in the future. Copyright © 2017. Published by Elsevier B.V.

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

Bertucci, M.; Michelato, P.; Moretti, M.

X-ray fluorescence probe for detection of foreign material inclusions on the inner surface of superconducting cavities has been developed and tested. The setup detects trace element content such as a few micrograms of impurities responsible for thermal breakdown phenomena limiting the cavity performance. The setup has been customized for the geometry of 1.3 GHz TESLA-type niobium cavities and focuses on the surface of equator area at around 103 mm from the centre axis of the cavities with around 20 mm detection spot. More precise localization of inclusions can be reconstructed by means of angular or lateral displacement of the cavity.more » Preliminary tests confirmed a very low detection limit for elements laying in the high efficiency spectrum zone (from 5 to 10 keV), and a high angular resolution allowing an accurate localization of defects within the equator surface.« less

Innovative Tools and Technology for Analysis of Single Cells and Cell-Cell Interaction.

PubMed

Konry, Tania; Sarkar, Saheli; Sabhachandani, Pooja; Cohen, Noa

2016-07-11

Heterogeneity in single-cell responses and intercellular interactions results from complex regulation of cell-intrinsic and environmental factors. Single-cell analysis allows not only detection of individual cellular characteristics but also correlation of genetic content with phenotypic traits in the same cell. Technological advances in micro- and nanofabrication have benefited single-cell analysis by allowing precise control of the localized microenvironment, cell manipulation, and sensitive detection capabilities. Additionally, microscale techniques permit rapid, high-throughput, multiparametric screening that has become essential for -omics research. This review highlights innovative applications of microscale platforms in genetic, proteomic, and metabolic detection in single cells; cell sorting strategies; and heterotypic cell-cell interaction. We discuss key design aspects of single-cell localization and isolation in microfluidic systems, dynamic and endpoint analyses, and approaches that integrate highly multiplexed detection of various intracellular species.

A simple high performance liquid chromatography method for analyzing paraquat in soil solution samples.

PubMed

Ouyang, Ying; Mansell, Robert S; Nkedi-Kizza, Peter

2004-01-01

A high performance liquid chromatography (HPLC) method with UV detection was developed to analyze paraquat (1,1'-dimethyl-4,4'-dipyridinium dichloride) herbicide content in soil solution samples. The analytical method was compared with the liquid scintillation counting (LSC) method using 14C-paraquat. Agreement obtained between the two methods was reasonable. However, the detection limit for paraquat analysis was 0.5 mg L(-1) by the HPLC method and 0.05 mg L(-1) by the LSC method. The LSC method was, therefore, 10 times more precise than the HPLC method for solution concentrations less than 1 mg L(-1). In spite of the high detection limit, the UC (nonradioactive) HPLC method provides an inexpensive and environmentally safe means for determining paraquat concentration in soil solution compared with the 14C-LSC method.

Detection and Identification of Archaeological Sites and Features Using Synthetic Aperture Radar (SAR) Data Collected from Airborne Platforms

DTIC Science & Technology

2006-04-26

sessions were used not only for signature development, but more 5 immediately to determine the spatial precision of images produced from...algorithms (e.g., NDVI and Tasseled Cap) available. The most instructive vectors were determined to be the SAR band polarizations vertically in the C...lands. Our principal, but not exclusive, focus has been on the use of high resolution airborne radar data in detection. in’<l’entoxy, and

Active cancellation - A means to zero dead-time pulse EPR.

PubMed

Franck, John M; Barnes, Ryan P; Keller, Timothy J; Kaufmann, Thomas; Han, Songi

2015-12-01

The necessary resonator employed in pulse electron paramagnetic resonance (EPR) rings after the excitation pulse and creates a finite detector dead-time that ultimately prevents the detection of signal from fast relaxing spin systems, hindering the application of pulse EPR to room temperature measurements of interesting chemical or biological systems. We employ a recently available high bandwidth arbitrary waveform generator (AWG) to produce a cancellation pulse that precisely destructively interferes with the resonant cavity ring-down. We find that we can faithfully detect EPR signal at all times immediately after, as well as during, the excitation pulse. This is a proof of concept study showcasing the capability of AWG pulses to precisely cancel out the resonator ring-down, and allow for the detection of EPR signal during the pulse itself, as well as the dead-time of the resonator. However, the applicability of this approach to conventional EPR experiments is not immediate, as it hinges on either (1) the availability of low-noise microwave sources and amplifiers to produce the necessary power for pulse EPR experiment or (2) the availability of very high conversion factor micro coil resonators that allow for pulse EPR experiments at modest microwave power. Copyright © 2015 Elsevier Inc. All rights reserved.

Sampling Methods for Detection and Monitoring of the Asian Citrus Psyllid (Hemiptera: Psyllidae).

PubMed

Monzo, C; Arevalo, H A; Jones, M M; Vanaclocha, P; Croxton, S D; Qureshi, J A; Stansly, P A

2015-06-01

The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama is a key pest of citrus due to its role as vector of citrus greening disease or "huanglongbing." ACP monitoring is considered an indispensable tool for management of vector and disease. In the present study, datasets collected between 2009 and 2013 from 245 citrus blocks were used to evaluate precision, sensitivity for detection, and efficiency of five sampling methods. The number of samples needed to reach a 0.25 standard error-mean ratio was estimated using Taylor's power law and used to compare precision among sampling methods. Comparison of detection sensitivity and time expenditure (cost) between stem-tap and other sampling methodologies conducted consecutively at the same location were also assessed. Stem-tap sampling was the most efficient sampling method when ACP densities were moderate to high and served as the basis for comparison with all other methods. Protocols that grouped trees near randomly selected locations across the block were more efficient than sampling trees at random across the block. Sweep net sampling was similar to stem-taps in number of captures per sampled unit, but less precise at any ACP density. Yellow sticky traps were 14 times more sensitive than stem-taps but much more time consuming and thus less efficient except at very low population densities. Visual sampling was efficient for detecting and monitoring ACP at low densities. Suction sampling was time consuming and taxing but the most sensitive of all methods for detection of sparse populations. This information can be used to optimize ACP monitoring efforts. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Automatic processing of induced events in the geothermal reservoirs Landau and Insheim, Germany

NASA Astrophysics Data System (ADS)

Olbert, Kai; Küperkoch, Ludger; Meier, Thomas

2016-04-01

Induced events can be a risk to local infrastructure that need to be understood and evaluated. They represent also a chance to learn more about the reservoir behavior and characteristics. Prior to the analysis, the waveform data must be processed consistently and accurately to avoid erroneous interpretations. In the framework of the MAGS2 project an automatic off-line event detection and a phase onset time determination algorithm are applied to induced seismic events in geothermal systems in Landau and Insheim, Germany. The off-line detection algorithm works based on a cross-correlation of continuous data taken from the local seismic network with master events. It distinguishes events between different reservoirs and within the individual reservoirs. Furthermore, it provides a location and magnitude estimation. Data from 2007 to 2014 are processed and compared with other detections using the SeisComp3 cross correlation detector and a STA/LTA detector. The detected events are analyzed concerning spatial or temporal clustering. Furthermore the number of events are compared to the existing detection lists. The automatic phase picking algorithm combines an AR-AIC approach with a cost function to find precise P1- and S1-phase onset times which can be used for localization and tomography studies. 800 induced events are processed, determining 5000 P1- and 6000 S1-picks. The phase onset times show a high precision with mean residuals to manual phase picks of 0s (P1) to 0.04s (S1) and standard deviations below ±0.05s. The received automatic picks are applied to relocate a selected number of events to evaluate influences on the location precision.

OrganismTagger: detection, normalization and grounding of organism entities in biomedical documents.

PubMed

Naderi, Nona; Kappler, Thomas; Baker, Christopher J O; Witte, René

2011-10-01

Semantic tagging of organism mentions in full-text articles is an important part of literature mining and semantic enrichment solutions. Tagged organism mentions also play a pivotal role in disambiguating other entities in a text, such as proteins. A high-precision organism tagging system must be able to detect the numerous forms of organism mentions, including common names as well as the traditional taxonomic groups: genus, species and strains. In addition, such a system must resolve abbreviations and acronyms, assign the scientific name and if possible link the detected mention to the NCBI Taxonomy database for further semantic queries and literature navigation. We present the OrganismTagger, a hybrid rule-based/machine learning system to extract organism mentions from the literature. It includes tools for automatically generating lexical and ontological resources from a copy of the NCBI Taxonomy database, thereby facilitating system updates by end users. Its novel ontology-based resources can also be reused in other semantic mining and linked data tasks. Each detected organism mention is normalized to a canonical name through the resolution of acronyms and abbreviations and subsequently grounded with an NCBI Taxonomy database ID. In particular, our system combines a novel machine-learning approach with rule-based and lexical methods for detecting strain mentions in documents. On our manually annotated OT corpus, the OrganismTagger achieves a precision of 95%, a recall of 94% and a grounding accuracy of 97.5%. On the manually annotated corpus of Linnaeus-100, the results show a precision of 99%, recall of 97% and grounding accuracy of 97.4%. The OrganismTagger, including supporting tools, resources, training data and manual annotations, as well as end user and developer documentation, is freely available under an open-source license at http://www.semanticsoftware.info/organism-tagger. witte@semanticsoftware.info.

An improved method for precise automatic co-registration of moderate and high-resolution spacecraft imagery

NASA Technical Reports Server (NTRS)

Bryant, Nevin A.; Logan, Thomas L.; Zobrist, Albert L.

2006-01-01

Improvements to the automated co-registration and change detection software package, AFIDS (Automatic Fusion of Image Data System) has recently completed development for and validation by NGA/GIAT. The improvements involve the integration of the AFIDS ultra-fine gridding technique for horizontal displacement compensation with the recently evolved use of Rational Polynomial Functions/ Coefficients (RPFs/RPCs) for image raster pixel position to Latitude/Longitude indexing. Mapping and orthorectification (correction for elevation effects) of satellite imagery defies exact projective solutions because the data are not obtained from a single point (like a camera), but as a continuous process from the orbital path. Standard image processing techniques can apply approximate solutions, but advances in the state-of-the-art had to be made for precision change-detection and time-series applications where relief offsets become a controlling factor. The earlier AFIDS procedure required the availability of a camera model and knowledge of the satellite platform ephemeredes. The recent design advances connect the spacecraft sensor Rational Polynomial Function, a deductively developed model, with the AFIDS ultrafine grid, an inductively developed representation of the relationship raster pixel position to latitude /longitude. As a result, RPCs can be updated by AFIDS, a situation often necessary due to the accuracy limits of spacecraft navigation systems. An example of precision change detection will be presented from Quickbird.

Determination of boldine in plasma by high-performance liquid chromatography.

PubMed

Speisky, H; Cassels, B K; Nieto, S; Valenzuela, A; Nuñez-Vergara, L J

1993-02-26

A sensitive method for the determination of boldine in blood plasma is described. The procedure involves a direct pH-buffered chloroform extraction of boldine from blood plasma, followed by its assay under isocratic conditions by HPLC with UV detection. The extraction recovery is excellent, and sensitivity and precision of the method are very high, when applied to plasma samples containing pharmacologically relevant concentrations of boldine.

Simultaneous Determination of Withanolide A and Bacoside A in Spansules by High-Performance Thin-Layer Chromatography

PubMed Central

Shinde, P B; Aragade, P D; Agrawal, M R; Deokate, U A; Khadabadi, S S

2011-01-01

The objective of this work was to develop and validate a simple, rapid, precise, and accurate high performance thin layer chromatography method for simultaneous determination of withanolide A and bacoside A in combined dosage form. The stationary phase used was silica gel G60F254. The mobile phase used was mixture of ethyl acetate: methanol: toluene: water (4:1:1:0.5 v/v/v/v). The detection of spots was carried out at 320 nm using absorbance reflectance mode. The method was validated in terms of linearity, accuracy, precision and specificity. The calibration curve was found to be linear between 200 to 800 ng/spot for withanolide A and 50 to 350 ng/spot for bacoside A. The limit of detection and limit of quantification for the withanolide A were found to be 3.05 and 10.06 ng/spot, respectively and for bacoside A 8.3 and 27.39 ng/spot, respectively. The proposed method can be successfully used to determine the drug content of marketed formulation. PMID:22303073

Simultaneous determination of withanolide a and bacoside a in spansules by high-performance thin-layer chromatography.

PubMed

Shinde, P B; Aragade, P D; Agrawal, M R; Deokate, U A; Khadabadi, S S

2011-03-01

The objective of this work was to develop and validate a simple, rapid, precise, and accurate high performance thin layer chromatography method for simultaneous determination of withanolide A and bacoside A in combined dosage form. The stationary phase used was silica gel G60F(254). The mobile phase used was mixture of ethyl acetate: methanol: toluene: water (4:1:1:0.5 v/v/v/v). The detection of spots was carried out at 320 nm using absorbance reflectance mode. The method was validated in terms of linearity, accuracy, precision and specificity. The calibration curve was found to be linear between 200 to 800 ng/spot for withanolide A and 50 to 350 ng/spot for bacoside A. The limit of detection and limit of quantification for the withanolide A were found to be 3.05 and 10.06 ng/spot, respectively and for bacoside A 8.3 and 27.39 ng/spot, respectively. The proposed method can be successfully used to determine the drug content of marketed formulation.

PLANETARY TRANSIT CANDIDATES IN THE CSTAR FIELD: ANALYSIS OF THE 2008 DATA

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

Wang, Songhu; Zhang, Hui; Zhou, Ji-Lin

2014-04-01

The Chinese Small Telescope ARray (CSTAR) is a group of four identical, fully automated, static 14.5 cm telescopes. CSTAR is located at Dome A, Antarctica and covers 20 deg{sup 2} of sky around the South Celestial Pole. The installation is designed to provide high-cadence photometry for the purpose of monitoring the quality of the astronomical observing conditions at Dome A and detecting transiting exoplanets. CSTAR has been operational since 2008, and has taken a rich and high-precision photometric data set of 10,690 stars. In the first observing season, we obtained 291,911 qualified science frames with 20 s integrations in themore » i band. Photometric precision reaches ∼4 mmag at 20 s cadence at i = 7.5 and is ∼20 mmag at i = 12. Using robust detection methods, 10 promising exoplanet candidates were found. Four of these were found to be giants using spectroscopic follow-up. All of these transit candidates are presented here along with the discussion of their detailed properties as well as the follow-up observations.« less

Planetary Transit Candidates in the CSTAR Field: Analysis of the 2008 Data

NASA Astrophysics Data System (ADS)

Wang, Songhu; Zhang, Hui; Zhou, Ji-Lin; Zhou, Xu; Yang, Ming; Wang, Lifan; Bayliss, D.; Zhou, G.; Ashley, M. C. B.; Fan, Zhou; Feng, Long-Long; Gong, Xuefei; Lawrence, J. S.; Liu, Huigen; Liu, Qiang; Luong-Van, D. M.; Ma, Jun; Meng, Zeyang; Storey, J. W. V.; Wittenmyer, R. A.; Wu, Zhenyu; Yan, Jun; Yang, Huigen; Yang, Ji; Yang, Jiayi; Yuan, Xiangyan; Zhang, Tianmeng; Zhu, Zhenxi; Zou, Hu

2014-04-01

The Chinese Small Telescope ARray (CSTAR) is a group of four identical, fully automated, static 14.5 cm telescopes. CSTAR is located at Dome A, Antarctica and covers 20 deg2 of sky around the South Celestial Pole. The installation is designed to provide high-cadence photometry for the purpose of monitoring the quality of the astronomical observing conditions at Dome A and detecting transiting exoplanets. CSTAR has been operational since 2008, and has taken a rich and high-precision photometric data set of 10,690 stars. In the first observing season, we obtained 291,911 qualified science frames with 20 s integrations in the i band. Photometric precision reaches ~4 mmag at 20 s cadence at i = 7.5 and is ~20 mmag at i = 12. Using robust detection methods, 10 promising exoplanet candidates were found. Four of these were found to be giants using spectroscopic follow-up. All of these transit candidates are presented here along with the discussion of their detailed properties as well as the follow-up observations.

An Improved Image Matching Method Based on Surf Algorithm

NASA Astrophysics Data System (ADS)

Chen, S. J.; Zheng, S. Z.; Xu, Z. G.; Guo, C. C.; Ma, X. L.

2018-04-01

Many state-of-the-art image matching methods, based on the feature matching, have been widely studied in the remote sensing field. These methods of feature matching which get highly operating efficiency, have a disadvantage of low accuracy and robustness. This paper proposes an improved image matching method which based on the SURF algorithm. The proposed method introduces color invariant transformation, information entropy theory and a series of constraint conditions to increase feature points detection and matching accuracy. First, the model of color invariant transformation is introduced for two matching images aiming at obtaining more color information during the matching process and information entropy theory is used to obtain the most information of two matching images. Then SURF algorithm is applied to detect and describe points from the images. Finally, constraint conditions which including Delaunay triangulation construction, similarity function and projective invariant are employed to eliminate the mismatches so as to improve matching precision. The proposed method has been validated on the remote sensing images and the result benefits from its high precision and robustness.

[Development of chlorophyll concentration nondestructive measurement instrument based on spectral analysis technology].

PubMed

Li, Qing-Bo; Xu, Yu-Po; Zhang, Chao-Hang; Zhang, Guang-Jun; Wu, Jin-Guang

2009-10-01

A portable nondestructive measuring instrument for plant chlorophyll was developed, which can perform real-time, quick and nondestructive measurement of chlorophyll. The instrument is mainly composed of four parts, including leaves clamp, driving circuit of light source, photoelectric detection and signal conditioning circuit and micro-control system. A new scheme of light source driving was proposed, which can not only achieve constant current, but also control the current by digital signal. The driving current can be changed depending on different light source and measurement situation by actual operation, which resolves the matching problem of output intensity of light source and input range of photoelectric detector. In addition, an integrative leaves clamp was designed, which simplified the optical structure, enhanced the stability of apparatus, decreased the loss of incident light and improved the signal-to-noise ratio and precision. The photoelectric detection and signal conditioning circuit achieve the conversion between optical signal and electrical signal, and make the electrical signal meet the requirement of AD conversion, and the photo detector is S1133-14 of Hamamatsu Company, with a high detection precision. The micro-control system mainly achieves control function, dealing with data, data storage and so on. As the most important component, microprocessor MSP430F149 of TI Company has many advantages, such as high processing speed, low power, high stability and so on. And it has an in-built 12 bit AD converter, so the data-acquisition circuit is simpler. MSP430F149 is suitable for portable instrument. In the calibration experiment of the instrument, the standard value was measured by chlorophyll meter SPAD-502, multiple linear calibration models were built, and the instrument performance was evaluated. The correlation coefficient between chlorophyll prediction value and standard value is 0.97, and the root mean square error of prediction is about 1.3 SPAD. In the evaluation experiment of the instrument repeatability, the root mean square error is 0.1 SPAD. Results of the calibration experiment show that the instrument has high measuring precision and high stability.

Resonant ultrasound spectroscopy and non-destructive testing

NASA Astrophysics Data System (ADS)

Migliori, A.; Darling, T. W.

The use of mechanical resonances to test properties of materials is perhaps older than the industrial revolution. Early documented cases of British railroad engineers tapping the wheels of a train and using the sound to detect cracks perhaps mark the first real use of resonances to test the integrity of high-performance alloys. Attempts were made in the following years to understand the resonances of solids mathematically, based on the shape and composition. But Nobel Laureate Lord Rayleigh best summarized the state of affairs in 1894, stating 'the problem has, for the most part, resisted attack'. More recently, modern computers and electronics have enabled Anderson and co-workers with their work on minerals, and our work at Los Alamos on new materials and manufactured components to advance the use of resonances to a precision non-destructive testing tool that makes anisotropic modulus measurements, defect detection and geometry error detection routine. The result is that resonances can achieve the highest absolute accuracy for any dynamic modulus measurement technique, can be used on the smallest samples, and can also enable detection of errors in certain classes of precision manufactured components faster and more accurately than any other technique.

Determination of cocaine, benzoylecgonine and cocaethylene in human hair by solid-phase microextraction and gas chromatography-mass spectrometry.

PubMed

de Toledo, Fernanda Crossi Pereira; Yonamine, Mauricio; de Moraes Moreau, Regina Lucia; Silva, Ovandir Alves

2003-12-25

The present work describes a highly precise and sensitive method developed to detect cocaine (COC), benzoylecgonine (BE, its main metabolite) and cocaethylene (CE, transesterification product of the coingestion of COC with ethanol) in human head hair samples. The method was based on an alkylchloroformate derivatization of benzoylecgonine and the extraction of the analytes by solid-phase microextraction (SPME). Gas chromatography-mass spectrometry (GC-MS) was used to identify and quantify the analytes in selected ion monitoring mode (SIM). The limits of quantification and detection (LOQ and LOD) were: 0.1 ng/mg for COC and CE, and 0.5 ng/mg for BE. Good inter- and intra-assay precision was observed. The dynamic range of the assay was 0.1-50 ng/mg. The method is not time consuming and was shown to be easy to perform.

Digital detection of endonuclease mediated gene disruption in the HIV provirus

PubMed Central

Sedlak, Ruth Hall; Liang, Shu; Niyonzima, Nixon; De Silva Feelixge, Harshana S.; Roychoudhury, Pavitra; Greninger, Alexander L.; Weber, Nicholas D.; Boissel, Sandrine; Scharenberg, Andrew M.; Cheng, Anqi; Magaret, Amalia; Bumgarner, Roger; Stone, Daniel; Jerome, Keith R.

2016-01-01

Genome editing by designer nucleases is a rapidly evolving technology utilized in a highly diverse set of research fields. Among all fields, the T7 endonuclease mismatch cleavage assay, or Surveyor assay, is the most commonly used tool to assess genomic editing by designer nucleases. This assay, while relatively easy to perform, provides only a semi-quantitative measure of mutation efficiency that lacks sensitivity and accuracy. We demonstrate a simple droplet digital PCR assay that quickly quantitates a range of indel mutations with detection as low as 0.02% mutant in a wild type background and precision (≤6%CV) and accuracy superior to either mismatch cleavage assay or clonal sequencing when compared to next-generation sequencing. The precision and simplicity of this assay will facilitate comparison of gene editing approaches and their optimization, accelerating progress in this rapidly-moving field. PMID:26829887

Designing Successful Next-Generation Instruments to Detect the Epoch of Reionization

NASA Astrophysics Data System (ADS)

Thyagarajan, Nithyanandan; Hydrogen Epoch of Reionization Array (HERA) team, Murchison Widefield Array (MWA) team

2018-01-01

The Epoch of Reionization (EoR) signifies a period of intense evolution of the Inter-Galactic Medium (IGM) in the early Universe caused by the first generations of stars and galaxies, wherein they turned the neutral IGM to be completely ionized by redshift ≥ 6. This important epoch is poorly explored to date. Measurement of redshifted 21 cm line from neutral Hydrogen during the EoR is promising to provide the most direct constraints of this epoch. Ongoing experiments to detect redshifted 21 cm power spectrum during reionization, including the Murchison Widefield Array (MWA), Precision Array for Probing the Epoch of Reionization (PAPER), and the Low Frequency Array (LOFAR), appear to be severely affected by bright foregrounds and unaccounted instrumental systematics. For example, the spectral structure introduced by wide-field effects, aperture shapes and angular power patterns of the antennas, electrical and geometrical reflections in the antennas and electrical paths, and antenna position errors can be major limiting factors. These mimic the 21 cm signal and severely degrade the instrument performance. It is imperative for the next-generation of experiments to eliminate these systematics at their source via robust instrument design. I will discuss a generic framework to set cosmologically motivated antenna performance specifications and design strategies using the Precision Radio Interferometry Simulator (PRISim) -- a high-precision tool that I have developed for simulations of foregrounds and the instrument transfer function intended primarily for 21 cm EoR studies, but also broadly applicable to interferometer-based intensity mapping experiments. The Hydrogen Epoch of Reionization Array (HERA), designed in-part based on this framework, is expected to detect the 21 cm signal with high significance. I will present this framework and the simulations, and their potential for designing upcoming radio instruments such as HERA and the Square Kilometre Array (SKA).

How Do Statistical Detection Methods Compare to Entropy Measures

DTIC Science & Technology

2012-08-28

October 2001. It is known as RS attack or “Reliable Detection of LSB Steganography in Grayscale and color images ”. The algorithm they use is very...precise for the detection of pseudo-aleatory LSB steganography . Its precision varies with the image but, its referential value is a 0.005 bits by...Jessica Fridrich, Miroslav Goljan, Rui Du, "Detecting LSB Steganography in Color and Gray-Scale Images ," IEEE Multimedia, vol. 8, no. 4, pp. 22-28, Oct

Surveying Nearby M dwarfs with Gaia: A Treasure Trove for Exoplanet Astrophysics

NASA Astrophysics Data System (ADS)

Sozzetti, A.; Tinetti, G.; Lattanzi, M. G.; Micela, G.; Morbidelli, R.; Giacobbe, P.

2011-10-01

Cool, nearby M dwarfs within a few tens of parsecs from the Sun are today becoming the focus of dedicated experiments in the realm of exoplanets astrophysics. This is due to the shift in theoretical paradigms in light of new observations, and thanks to the improved understanding of the observational opportunities for planet detection and characterization provided by this sample. Gaia, in its all-sky survey, will deliver precision astrometry for a magnitude-limited (V=20) sample of M dwarfs in the vicinity of the Sun, providing an inventory of cool nearby stars with a much higher degree of completeness (particularly for late sub-types) with respect to currently available catalogs. We gauge the Gaia potential for precision astrometry of exoplanets orbiting a sample of actual M stars within 30 pc from the Sun. The stellar reservoir is carefully selected based on cross-correlation among catalogs in the literature (e.g., Lepine, PMSU).We express Gaia sensitivity thresholds as a function of system parameters and in view of the latest mission profile, including the most up-to-date astrometric error model. The simulations also provide insight on the capability of high-precision astrometry to reconstruct the underlying orbital elements and mass distributions of the generated companions. We investigate the synergy between the Gaia data on nearby M dwarfs and other ground-based and spaceborne programs for planet detection and characterization, with a particular focus on: a) the improvements in the determination of transiting planet parameters thanks to the exquisitely precise stellar distances determined by Gaia; b) the betterment in orbit modeling when Gaia astrometry and precision radial-velocities are available for the same targets; and c) the ability of Gaia to carefully predict the ephemerides of detected (transiting and non-transiting) planets aroundM stars, for the purpose of spectroscopic characterization of their atmospheres with dedicated observatories in space, such as EChO.

The detection of cryptic Plasmodium infection among villagers in Attapeu province, Lao PDR.

PubMed

Iwagami, Moritoshi; Keomalaphet, Sengdeuane; Khattignavong, Phonepadith; Soundala, Pheovaly; Lorphachan, Lavy; Matsumoto-Takahashi, Emilie; Strobel, Michel; Reinharz, Daniel; Phommasansack, Manisack; Hongvanthong, Bouasy; Brey, Paul T; Kano, Shigeyuki

2017-12-01

Although the malaria burden in the Lao PDR has gradually decreased, the elimination of malaria by 2030 presents many challenges. Microscopy and malaria rapid diagnostic tests (RDTs) are used to diagnose malaria in the Lao PDR; however, some studies have reported the prevalence of sub-microscopic Plasmodium infections or asymptomatic Plasmodium carriers in endemic areas. Thus, highly sensitive detection methods are needed to understand the precise malaria situation in these areas. A cross-sectional malaria field survey was conducted in 3 highly endemic malaria districts (Xaysetha, Sanamxay, Phouvong) in Attapeu province, Lao PDR in 2015, to investigate the precise malaria endemicity in the area; 719 volunteers from these villages participated in the survey. Microscopy, RDTs and a real-time nested PCR were used to detect Plasmodium infections and their results were compared. A questionnaire survey of all participants was also conducted to estimate risk factors of Plasmodium infection. Numbers of infections detected by the three methods were microscopy: P. falciparum (n = 1), P. vivax (n = 2); RDTs: P. falciparum (n = 2), P. vivax (n = 3); PCR: Plasmodium (n = 47; P. falciparum [n = 4], P. vivax [n = 41], mixed infection [n = 2]; 6.5%, 47/719). Using PCR as a reference, the sensitivity and specificity of microscopy were 33.3% and 100.0%, respectively, for detecting P. falciparum infection, and 7.0% and 100.0%, for detecting P. vivax infection. Among the 47 participants with parasitemia, only one had a fever (≥37.5°C) and 31 (66.0%) were adult males. Risk factors of Plasmodium infection were males and soldiers, whereas a risk factor of asymptomatic Plasmodium infection was a history of ≥3 malaria episodes. There were many asymptomatic Plasmodium carriers in the study areas of Attapeu province in 2015. Adult males, probably soldiers, were at high risk for malaria infection. P. vivax, the dominant species, accounted for 87.2% of the Plasmodium infections among the participants. To achieve malaria elimination in the Lao PDR, highly sensitive diagnostic tests, including PCR-based diagnostic methods should be used, and plans targeting high-risk populations and elimination of P. vivax should be designed and implemented.

In-Situ Real-Time Focus Detection during Laser Processing Using Double-Hole Masks and Advanced Image Sensor Software

PubMed Central

Hoang, Phuong Le; Ahn, Sanghoon; Kim, Jeng-o; Kang, Heeshin; Noh, Jiwhan

2017-01-01

In modern high-intensity ultrafast laser processing, detecting the focal position of the working laser beam, at which the intensity is the highest and the beam diameter is the lowest, and immediately locating the target sample at that point are challenging tasks. A system that allows in-situ real-time focus determination and fabrication using a high-power laser has been in high demand among both engineers and scientists. Conventional techniques require the complicated mathematical theory of wave optics, employing interference as well as diffraction phenomena to detect the focal position; however, these methods are ineffective and expensive for industrial application. Moreover, these techniques could not perform detection and fabrication simultaneously. In this paper, we propose an optical design capable of detecting the focal point and fabricating complex patterns on a planar sample surface simultaneously. In-situ real-time focus detection is performed using a bandpass filter, which only allows for the detection of laser transmission. The technique enables rapid, non-destructive, and precise detection of the focal point. Furthermore, it is sufficiently simple for application in both science and industry for mass production, and it is expected to contribute to the next generation of laser equipment, which can be used to fabricate micro-patterns with high complexity. PMID:28671566

Real-Time Gait Event Detection Based on Kinematic Data Coupled to a Biomechanical Model.

PubMed

Lambrecht, Stefan; Harutyunyan, Anna; Tanghe, Kevin; Afschrift, Maarten; De Schutter, Joris; Jonkers, Ilse

2017-03-24

Real-time detection of multiple stance events, more specifically initial contact (IC), foot flat (FF), heel off (HO), and toe off (TO), could greatly benefit neurorobotic (NR) and neuroprosthetic (NP) control. Three real-time threshold-based algorithms have been developed, detecting the aforementioned events based on kinematic data in combination with a biomechanical model. Data from seven subjects walking at three speeds on an instrumented treadmill were used to validate the presented algorithms, accumulating to a total of 558 steps. The reference for the gait events was obtained using marker and force plate data. All algorithms had excellent precision and no false positives were observed. Timing delays of the presented algorithms were similar to current state-of-the-art algorithms for the detection of IC and TO, whereas smaller delays were achieved for the detection of FF. Our results indicate that, based on their high precision and low delays, these algorithms can be used for the control of an NR/NP, with the exception of the HO event. Kinematic data is used in most NR/NP control schemes and is thus available at no additional cost, resulting in a minimal computational burden. The presented methods can also be applied for screening pathological gait or gait analysis in general in/outside of the laboratory.

High resolution Florida IR silicon immersion grating spectrometer and an M dwarf planet survey

NASA Astrophysics Data System (ADS)

Ge, Jian; Powell, Scott; Zhao, Bo; Wang, Ji; Fletcher, Adam; Schofield, Sidney; Liu, Jian; Muterspaugh, Matthew; Blake, Cullen; Barnes, Rory

2012-09-01

We report the system design and predicted performance of the Florida IR Silicon immersion grating spectromeTer (FIRST). This new generation cryogenic IR spectrograph offers broad-band high resolution IR spectroscopy with R=72,000 at 1.4-1.8 μm and R=60,000 at 0.8-1.35 μm in a single exposure with a 2kx2k H2RG IR array. It is enabled by a compact design using an extremely high dispersion silicon immersion grating (SIG) and an R4 echelle with a 50 mm diameter pupil in combination with an Image Slicer. This instrument is operated in vacuum with temperature precisely controlled to reach long term stability for high precision radial velocity (RV) measurements of nearby stars, especially M dwarfs and young stars. The primary technical goal is to reach better than 4 m/s long term RV precision with J<9 M dwarfs within 30 min exposures. This instrument is scheduled to be commissioned at the Tennessee State University (TSU) 2-m Automatic Spectroscopic Telescope (AST) at Fairborn Observatory in spring 2013. FIRST can also be used for observing transiting planets, young stellar objects (YSOs), magnetic fields, binaries, brown dwarfs (BDs), ISM and stars. We plan to launch the FIRST NIR M dwarf planet survey in 2014 after FIRST is commissioned at the AST. This NIR M dwarf survey is the first large-scale NIR high precision Doppler survey dedicated to detecting and characterizing planets around 215 nearby M dwarfs with J< 10. Our primary science goal is to look for habitable Super-Earths around the late M dwarfs and also to identify transiting systems for follow-up observations with JWST to measure the planetary atmospheric compositions and study their habitability. Our secondary science goal is to detect and characterize a large number of planets around M dwarfs to understand the statistics of planet populations around these low mass stars and constrain planet formation and evolution models. Our survey baseline is expected to detect ~30 exoplanets, including 10 Super Earths, within 100 day periods. About half of the Super-Earths are in their habitable zones and one of them may be a transiting planet. The AST, with its robotic control and ease of switching between instruments (in seconds), enables great flexibility and efficiency, and enables an optimal strategy, in terms of schedule and cadence, for this NIR M dwarf planet survey.

EVEREST: Pixel Level Decorrelation of K2 Light Curves

NASA Astrophysics Data System (ADS)

Luger, Rodrigo; Agol, Eric; Kruse, Ethan; Barnes, Rory; Becker, Andrew; Foreman-Mackey, Daniel; Deming, Drake

2016-10-01

We present EPIC Variability Extraction and Removal for Exoplanet Science Targets (EVEREST), an open-source pipeline for removing instrumental noise from K2 light curves. EVEREST employs a variant of pixel level decorrelation to remove systematics introduced by the spacecraft’s pointing error and a Gaussian process to capture astrophysical variability. We apply EVEREST to all K2 targets in campaigns 0-7, yielding light curves with precision comparable to that of the original Kepler mission for stars brighter than {K}p≈ 13, and within a factor of two of the Kepler precision for fainter targets. We perform cross-validation and transit injection and recovery tests to validate the pipeline, and compare our light curves to the other de-trended light curves available for download at the MAST High Level Science Products archive. We find that EVEREST achieves the highest average precision of any of these pipelines for unsaturated K2 stars. The improved precision of these light curves will aid in exoplanet detection and characterization, investigations of stellar variability, asteroseismology, and other photometric studies. The EVEREST pipeline can also easily be applied to future surveys, such as the TESS mission, to correct for instrumental systematics and enable the detection of low signal-to-noise transiting exoplanets. The EVEREST light curves and the source code used to generate them are freely available online.

Detecting and Characterizing Semantic Inconsistencies in Ported Code

NASA Technical Reports Server (NTRS)

Ray, Baishakhi; Kim, Miryung; Person,Suzette; Rungta, Neha

2013-01-01

Adding similar features and bug fixes often requires porting program patches from reference implementations and adapting them to target implementations. Porting errors may result from faulty adaptations or inconsistent updates. This paper investigates (1) the types of porting errors found in practice, and (2) how to detect and characterize potential porting errors. Analyzing version histories, we define five categories of porting errors, including incorrect control- and data-flow, code redundancy, inconsistent identifier renamings, etc. Leveraging this categorization, we design a static control- and data-dependence analysis technique, SPA, to detect and characterize porting inconsistencies. Our evaluation on code from four open-source projects shows that SPA can detect porting inconsistencies with 65% to 73% precision and 90% recall, and identify inconsistency types with 58% to 63% precision and 92% to 100% recall. In a comparison with two existing error detection tools, SPA improves precision by 14 to 17 percentage points.

Laser ablation inductively coupled plasma mass spectrometry for direct isotope ratio measurements on solid samples

NASA Astrophysics Data System (ADS)

Pickhardt, Carola; Dietze, Hans-Joachim; Becker, J. Sabine

2005-04-01

Isotope ratio measurements have been increasingly used in quite different application fields, e.g., for the investigation of isotope variation in nature, in geoscience (geochemistry and geochronology), in cosmochemistry and planetary science, in environmental science, e.g., in environmental monitoring, or by the application of the isotope dilution technique for quantification purposes using stable or radioactive high-enriched isotope tracers. Due to its high sensitivity, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is today a challenging mass spectrometric technique for the direct determination of precise and accurate isotope ratios in solid samples. In comparison to laser ablation quadrupole ICP-MS (LA-ICP-QMS), laser ablation coupled to a double-focusing sector field ICP-MS (LA-ICP-SFMS) with single ion detection offers a significant improvement of sensitivity at low mass resolution, whereby isotope ratios can be measured with a precision to 0.1% relative standard deviation (R.S.D.). In LA-ICP-SFMS, many disturbing isobaric interferences of analyte and molecular ions can be separated at the required mass resolution (e.g., 40Ar16O+ and 56Fe+ for iron isotope ratio measurements). The precision on isotope ratio measurements was improved by one order of magnitude via the simultaneous detection of mass-separated ion currents of isotopes using multiple ion collectors in LA-ICP-MS (LA-MC-ICP-MS). The paper discusses the state of the art, the challenges and limits in isotope ratio measurements by LA-ICP-MS using different instrumentations at the trace and ultratrace level in different fields of application as in environmental and biological research, geochemistry and geochronology with respect to their precision and accuracy.

Supervised Outlier Detection in Large-Scale Mvs Point Clouds for 3d City Modeling Applications

NASA Astrophysics Data System (ADS)

Stucker, C.; Richard, A.; Wegner, J. D.; Schindler, K.

2018-05-01

We propose to use a discriminative classifier for outlier detection in large-scale point clouds of cities generated via multi-view stereo (MVS) from densely acquired images. What makes outlier removal hard are varying distributions of inliers and outliers across a scene. Heuristic outlier removal using a specific feature that encodes point distribution often delivers unsatisfying results. Although most outliers can be identified correctly (high recall), many inliers are erroneously removed (low precision), too. This aggravates object 3D reconstruction due to missing data. We thus propose to discriminatively learn class-specific distributions directly from the data to achieve high precision. We apply a standard Random Forest classifier that infers a binary label (inlier or outlier) for each 3D point in the raw, unfiltered point cloud and test two approaches for training. In the first, non-semantic approach, features are extracted without considering the semantic interpretation of the 3D points. The trained model approximates the average distribution of inliers and outliers across all semantic classes. Second, semantic interpretation is incorporated into the learning process, i.e. we train separate inlieroutlier classifiers per semantic class (building facades, roof, ground, vegetation, fields, and water). Performance of learned filtering is evaluated on several large SfM point clouds of cities. We find that results confirm our underlying assumption that discriminatively learning inlier-outlier distributions does improve precision over global heuristics by up to ≍ 12 percent points. Moreover, semantically informed filtering that models class-specific distributions further improves precision by up to ≍ 10 percent points, being able to remove very isolated building, roof, and water points while preserving inliers on building facades and vegetation.

Circumnuclear Molecular Disks in Early-type Galaxies: Physical Properties and Precision Black Hole Mass Measurements

NASA Astrophysics Data System (ADS)

Boizelle, Benjamin

2018-01-01

ALMA is now capable of providing the most precise determinations of the masses of supermassive black holes in early-type galaxies (ETGs). In ALMA Cycle 2 we began a program to map the molecular gas kinematics in nearby ETGs that host central dust disks as seen in Hubble Space Telescope imaging. These initial observations targeted CO(2-1) emission at ~0.3" resolution, corresponding roughly to the projected radii of influence of the central black holes. In all cases we detect significant (~108 M⊙) molecular gas reservoirs that are in dynamically cold rotation, providing the most sensitive probes of the inner gravitational potentials of luminous ETGs. Using these gas kinematics, we verify that these molecular disks are formally stable against gravitational fragmentation and collapse. In several galaxies we detect central high-velocity gas rotation that provides direct kinematic evidence for a black hole. For two of these targets, NGC 1332 and NGC 3258, we have obtained higher-resolution observations (0.044" and 0.09") in Cycles 3 and 4 that more fully map out the gas rotation within the gravitational sphere of influence. We present dynamical modeling results for these targets, demonstrating that ALMA observations can enable black hole mass measurements at a precision of 10% or better, with minimal susceptibility to the systematic uncertainties that affect other methods of black hole mass measurement in ETGs. We discuss the impact of future high-resolution ALMA observations on black hole demographics and their potential to refine the high-mass end of the black hole-host galaxy scaling relationships.

Mobile mapping of methane emissions and isoscapes

NASA Astrophysics Data System (ADS)

Takriti, Mounir; Ward, Sue; Wynn, Peter; Elias, Dafydd; McNamara, Niall

2017-04-01

Methane (CH4) is a potent greenhouse gas emitted from a variety of natural and anthropogenic sources. It is crucial to accurately and efficiently detect CH4 emissions and identify their sources to improve our understanding of changing emission patterns as well as to identify ways to curtail their release into the atmosphere. However, using established methods this can be challenging as well as time and resource intensive due to the temporal and spatial heterogeneity of many sources. To address this problem, we have developed a vehicle mounted mobile system that combines high precision CH4 measurements with isotopic mapping and dual isotope source characterisation. We here present details of the development and testing of a unique system for the detection and isotopic analysis of CH4 plumes built around a Picarro isotopic (13C/12C) gas analyser and a high precision Los Gatos greenhouse gas analyser. Combined with micrometeorological measurements and a mechanism for collecting discrete samples for high precision dual isotope (13C/12C, 2H/1H) analysis the system enables mapping of concentrations as well as directional and isotope based source verification. We then present findings from our mobile methane surveys around the North West of England. This area includes a variety of natural and anthropogenic methane sources within a relatively small geographical area, including livestock farming, urban and industrial gas infrastructure, landfills and waste water treatment facilities, and wetlands. We show that the system was successfully able to locate leaks from natural gas infrastructure and emissions from agricultural activities and to distinguish isotope signatures from these sources.

Construction and evaluation of a capillary array DNA sequencer based on a micromachined sheath-flow cuvette.

PubMed

Crabtree, H J; Bay, S J; Lewis, D F; Zhang, J; Coulson, L D; Fitzpatrick, G A; Delinger, S L; Harrison, D J; Dovichi, N J

2000-04-01

A capillary array electrophoresis DNA sequencer is reported based on a micromachined sheath-flow cuvette as the detection chamber. This cuvette is equipped with a set of micromachined features that hold the capillaries in precise registration to ensure uniform spacing between the capillaries, in order to generate uniform hydrodynamic flow in the cuvette. A laser beam excites all of the samples simultaneously, and a microscope objective images fluorescence onto a set of avalanche photodiodes, which operate in the analog mode. A high-gain transimpedance amplifier is used for each photodiode, providing high duty-cycle detection of fluorescence.

Profile parameters of wheelset detection for high speed freight train

NASA Astrophysics Data System (ADS)

Yang, Kai; Ma, Li; Gao, Xiaorong; Wang, Li

2012-04-01

Because of freight train, in China, transports goods on railway freight line throughout the country, it does not depart from or return to engine shed during a long phase, thus we cannot monitor the quality of wheel set effectively. This paper provides a system which uses leaser and high speed camera, applies no-contact light section technology to get precise wheel set profile parameters. The paper employs clamping-track method to avoid complex railway ballast modification project. And detailed descript an improved image-tracking algorithm to extract central line from profile curve. For getting one pixel width and continuous line of the profile curve, uses local gray maximum points as direction control points to direct tracking direction. The results based on practical experiment show the system adapted to detection environment of high speed and high vibration, and it can effectively detect the wheelset geometric parameters with high accuracy. The system fills the gaps in wheel set detection for freight train in main line and has an enlightening function on monitoring the quality of wheel set.

Single-copy gene detection using branched DNA (bDNA) in situ hybridization.

PubMed

Player, A N; Shen, L P; Kenny, D; Antao, V P; Kolberg, J A

2001-05-01

We have developed a branched DNA in situ hybridization (bDNA ISH) method for detection of human papillomavirus (HPV) DNA in whole cells. Using human cervical cancer cell lines with known copies of HPV DNA, we show that the bDNA ISH method is highly sensitive, detecting as few as one or two copies of HPV DNA per cell. By modifying sample pretreatment, viral mRNA or DNA sequences can be detected using the same set of oligonucleotide probes. In experiments performed on mixed populations of cells, the bDNA ISH method is highly specific and can distinguish cells with HPV-16 from cells with HPV-18 DNA. Furthermore, we demonstrate that the bDNA ISH method provides precise localization, yielding positive signals retained within the subcellular compartments in which the target nucleic acid sequences are localized. As an effective and convenient means for nucleic acid detection, the bDNA ISH method is applicable to the detection of cancers and infectious agents. (J Histochem Cytochem 49:603-611, 2001)

A CO trace gas detection system based on continuous wave DFB-QCL

NASA Astrophysics Data System (ADS)

Dang, Jingmin; Yu, Haiye; Sun, Yujing; Wang, Yiding

2017-05-01

A compact and mobile system was demonstrated for the detection of carbon monoxide (CO) at trace level. This system adopted a high-power, continuous wave (CW), distributed feedback quantum cascade laser (DFB-QCL) operating at ∼22 °C as excitation source. Wavelength modulation spectroscopy (WMS) as well as second harmonic detection was used to isolate complex, overlapping spectral absorption features typical of ambient pressures and to achieve excellent specificity and high detection sensitivity. For the selected P(11) absorption line of CO molecule, located at 2099.083 cm-1, a limit of detection (LoD) of 26 ppb by volume (ppbv) at atmospheric pressure was achieved with a 1 s acquisition time. Allan deviation analysis was performed to investigate the long term performance of the CO detection system, and a measurement precision of 3.4 ppbv was observed with an optimal integration time of approximate 114 s, which verified the reliable and robust operation of the developed system.

A 3D Laser Profiling System for Rail Surface Defect Detection

PubMed Central

Li, Qingquan; Mao, Qingzhou; Zou, Qin

2017-01-01

Rail surface defects such as the abrasion, scratch and peeling often cause damages to the train wheels and rail bearings. An efficient and accurate detection of rail defects is of vital importance for the safety of railway transportation. In the past few decades, automatic rail defect detection has been studied; however, most developed methods use optic-imaging techniques to collect the rail surface data and are still suffering from a high false recognition rate. In this paper, a novel 3D laser profiling system (3D-LPS) is proposed, which integrates a laser scanner, odometer, inertial measurement unit (IMU) and global position system (GPS) to capture the rail surface profile data. For automatic defect detection, first, the deviation between the measured profile and a standard rail model profile is computed for each laser-imaging profile, and the points with large deviations are marked as candidate defect points. Specifically, an adaptive iterative closest point (AICP) algorithm is proposed to register the point sets of the measured profile with the standard rail model profile, and the registration precision is improved to the sub-millimeter level. Second, all of the measured profiles are combined together to form the rail surface through a high-precision positioning process with the IMU, odometer and GPS data. Third, the candidate defect points are merged into candidate defect regions using the K-means clustering. At last, the candidate defect regions are classified by a decision tree classifier. Experimental results demonstrate the effectiveness of the proposed laser-profiling system in rail surface defect detection and classification. PMID:28777323

Fast fMRI can detect oscillatory neural activity in humans.

PubMed

Lewis, Laura D; Setsompop, Kawin; Rosen, Bruce R; Polimeni, Jonathan R

2016-10-25

Oscillatory neural dynamics play an important role in the coordination of large-scale brain networks. High-level cognitive processes depend on dynamics evolving over hundreds of milliseconds, so measuring neural activity in this frequency range is important for cognitive neuroscience. However, current noninvasive neuroimaging methods are not able to precisely localize oscillatory neural activity above 0.2 Hz. Electroencephalography and magnetoencephalography have limited spatial resolution, whereas fMRI has limited temporal resolution because it measures vascular responses rather than directly recording neural activity. We hypothesized that the recent development of fast fMRI techniques, combined with the extra sensitivity afforded by ultra-high-field systems, could enable precise localization of neural oscillations. We tested whether fMRI can detect neural oscillations using human visual cortex as a model system. We detected small oscillatory fMRI signals in response to stimuli oscillating at up to 0.75 Hz within single scan sessions, and these responses were an order of magnitude larger than predicted by canonical linear models. Simultaneous EEG-fMRI and simulations based on a biophysical model of the hemodynamic response to neuronal activity suggested that the blood oxygen level-dependent response becomes faster for rapidly varying stimuli, enabling the detection of higher frequencies than expected. Accounting for phase delays across voxels further improved detection, demonstrating that identifying vascular delays will be of increasing importance with higher-frequency activity. These results challenge the assumption that the hemodynamic response is slow, and demonstrate that fMRI has the potential to map neural oscillations directly throughout the brain.

The optimum measurement precision evaluation for blood components using near-infrared spectra on 1000-2500 nm

NASA Astrophysics Data System (ADS)

Zhang, Ziyang; Sun, Di; Han, Tongshuai; Guo, Chao; Liu, Jin

2016-10-01

In the non-invasive blood components measurement using near infrared spectroscopy, the useful signals caused by the concentration variation in the interested components, such as glucose, hemoglobin, albumin etc., are relative weak. Then the signals may be greatly disturbed by a lot of noises in various ways. We improved the signals by using the optimum path-length for the used wavelength to get a maximum variation of transmitted light intensity when the concentration of a component varies. And after the path-length optimization for every wavelength in 1000-2500 nm, we present the detection limits for the components, including glucose, hemoglobin and albumin, when measuring them in a tissue phantom. The evaluated detection limits could be the best reachable precision level since it assumed the measurement uses a high signal-to-noise ratio (SNR) signal and the optimum path-length. From the results, available wavelengths in 1000-2500 nm for the three component measurements can be screened by comparing their detection limit values with their measurement limit requirements. For other blood components measurement, the evaluation their detection limits could also be designed using the method proposed in this paper. Moreover, we use an equation to estimate the absorbance at the optimum path-length for every wavelength in 1000-2500 nm caused by the three components. It could be an easy way to realize the evaluation because adjusting the sample cell's size to the precise path-length value for every wavelength is not necessary. This equation could also be referred to other blood components measurement using the optimum path-length for every used wavelength.

Digital PCR analysis of circulating nucleic acids.

PubMed

Hudecova, Irena

2015-10-01

Detection of plasma circulating nucleic acids (CNAs) requires the use of extremely sensitive and precise methods. The commonly used quantitative real-time polymerase chain reaction (PCR) poses certain technical limitations in relation to the precise measurement of CNAs whereas the costs of massively parallel sequencing are still relatively high. Digital PCR (dPCR) now represents an affordable and powerful single molecule counting strategy to detect minute amounts of genetic material with performance surpassing many quantitative methods. Microfluidic (chip) and emulsion (droplet)-based technologies have already been integrated into platforms offering hundreds to millions of nanoliter- or even picoliter-scale reaction partitions. The compelling observations reported in the field of cancer research, prenatal testing, transplantation medicine and virology support translation of this technology into routine use. Extremely sensitive plasma detection of rare mutations originating from tumor or placental cells among a large background of homologous sequences facilitates unraveling of the early stages of cancer or the detection of fetal mutations. Digital measurement of quantitative changes in plasma CNAs associated with cancer or graft rejection provides valuable information on the monitoring of disease burden or the recipient's immune response and subsequent therapy treatment. Furthermore, careful quantitative assessment of the viral load offers great value for effective monitoring of antiviral therapy for immunosuppressed or transplant patients. The present review describes the inherent features of dPCR that make it exceptionally robust in precise and sensitive quantification of CNAs. Moreover, I provide an insight into the types of potential clinical applications that have been developed by researchers to date. Copyright © 2015 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

First patients treated with a 1.5 T MRI-Linac: clinical proof of concept of a high-precision, high-field MRI guided radiotherapy treatment

NASA Astrophysics Data System (ADS)

Raaymakers, B. W.; Jürgenliemk-Schulz, I. M.; Bol, G. H.; Glitzner, M.; Kotte, A. N. T. J.; van Asselen, B.; de Boer, J. C. J.; Bluemink, J. J.; Hackett, S. L.; Moerland, M. A.; Woodings, S. J.; Wolthaus, J. W. H.; van Zijp, H. M.; Philippens, M. E. P.; Tijssen, R.; Kok, J. G. M.; de Groot-van Breugel, E. N.; Kiekebosch, I.; Meijers, L. T. C.; Nomden, C. N.; Sikkes, G. G.; Doornaert, P. A. H.; Eppinga, W. S. C.; Kasperts, N.; Kerkmeijer, L. G. W.; Tersteeg, J. H. A.; Brown, K. J.; Pais, B.; Woodhead, P.; Lagendijk, J. J. W.

2017-12-01

The integration of 1.5 T MRI functionality with a radiotherapy linear accelerator (linac) has been pursued since 1999 by the UMC Utrecht in close collaboration with Elekta and Philips. The idea behind this integrated device is to offer unrivalled, online and real-time, soft-tissue visualization of the tumour and the surroundings for more precise radiation delivery. The proof of concept of this device was given in 2009 by demonstrating simultaneous irradiation and MR imaging on phantoms, since then the device has been further developed and commercialized by Elekta. The aim of this work is to demonstrate the clinical feasibility of online, high-precision, high-field MRI guidance of radiotherapy using the first clinical prototype MRI-Linac. Four patients with lumbar spine bone metastases were treated with a 3 or 5 beam step-and-shoot IMRT plan. The IMRT plan was created while the patient was on the treatment table and based on the online 1.5 T MR images; pre-treatment CT was deformably registered to the online MRI to obtain Hounsfield values. Bone metastases were chosen as the first site as these tumors can be clearly visualized on MRI and the surrounding spine bone can be detected on the integrated portal imager. This way the portal images served as an independent verification of the MRI based guidance to quantify the geometric precision of radiation delivery. Dosimetric accuracy was assessed post-treatment from phantom measurements with an ionization chamber and film. Absolute doses were found to be highly accurate, with deviations ranging from 0.0% to 1.7% in the isocenter. The geometrical, MRI based targeting as confirmed using portal images was better than 0.5 mm, ranging from 0.2 mm to 0.4 mm. In conclusion, high precision, high-field, 1.5 T MRI guided radiotherapy is clinically feasible.

Molecular weight distribution of polysaccharides from edible seaweeds by high-performance size-exclusion chromatography (HPSEC).

PubMed

Gómez-Ordóñez, Eva; Jiménez-Escrig, Antonio; Rupérez, Pilar

2012-05-15

Biological properties of polysaccharides from seaweeds are related to their composition and structure. Many factors such as the kind of sugar, type of linkage or sulfate content of algal biopolymers exert an influence in the relationship between structure and function. Besides, the molecular weight (MW) also plays an important role. Thus, a simple, reliable and fast HPSEC method with refractive index detection was developed and optimized for the MW estimation of soluble algal polysaccharides. Chromatogram shape and repeatability of retention time was considerably improved when sodium nitrate was used instead of ultrapure water as mobile phase. Pullulan and dextran standards of different MW were used for method calibration and validation. Also, main polysaccharide standards from brown (alginate, fucoidan, laminaran) and red seaweeds (kappa- and iota-carrageenan) were used for quantification and method precision and accuracy. Relative standard deviation (RSD) of repeatability for retention time, peak areas and inter-day precision was below 0.7%, 2.5% and 2.6%, respectively, which indicated good repeatability and precision. Recoveries (96.3-109.8%) also showed its fairly good accuracy. Regarding linearity, main polysaccharide standards from brown or red seaweeds showed a highly satisfactory correlation coefficient (r>0.999). Moreover, a good sensitivity was shown, with corresponding limits of detection and quantitation in mg/mL of 0.05-0.21 and 0.16-0.31, respectively. The method was applied to the MW estimation of standard algal polysaccharides, as well as to the soluble polysaccharide fractions from the brown seaweed Saccharina latissima and the red Mastocarpus stellatus, respectively. Although distribution of molecular weight was broad, the good repeatability for retention time provided a good precision in MW estimation of polysaccharides. Water- and alkali-soluble fractions from S. latissima ranged from very high (>2400 kDa) to low MW compounds (<6 kDa); this high heterogeneity could be attributable to the complex polysaccharide composition of brown algae. Regarding M. stellatus, sulfated galactans followed a descending order of MW (>1400 kDa to <10 kDa), related to the different solubility of carrageenans in red seaweeds. In summary, the method developed allows for the molecular weight analysis of seaweed polysaccharides with very good precision, accuracy, linearity and sensitivity within a short time. Copyright © 2012 Elsevier B.V. All rights reserved.

Reverse phase HPLC method for detection and quantification of lupin seed γ-conglutin.

PubMed

Mane, Sharmilee; Bringans, Scott; Johnson, Stuart; Pareek, Vishnu; Utikar, Ranjeet

2017-09-15

A simple, selective and accurate reverse phase HPLC method was developed for detection and quantitation of γ-conglutin from lupin seed extract. A linear gradient of water and acetonitrile containing trifluoroacetic acid (TFA) on a reverse phase column (Agilent Zorbax 300SB C-18), with a flow rate of 0.8ml/min was able to produce a sharp and symmetric peak of γ-conglutin with a retention time at 29.16min. The identity of γ-conglutin in the peak was confirmed by mass spectrometry (MS/MS identification) and sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) analysis. The data obtained from MS/MS analysis was matched against the specified database to obtain the exact match for the protein of interest. The proposed method was validated in terms of specificity, linearity, sensitivity, precision, recovery and accuracy. The analytical parameters revealed that the validated method was capable of selectively performing a good chromatographic separation of γ-conglutin from the lupin seed extract with no interference of the matrix. The detection and quantitation limit of γ-conglutin were found to be 2.68μg/ml and 8.12μg/ml respectively. The accuracy (precision and recovery) analysis of the method was conducted under repeatable conditions on different days. Intra-day and inter-day precision values less than 0.5% and recovery greater than 97% indicated high precision and accuracy of the method for analysis of γ-conglutin. The method validation findings were reproducible and can be successfully applied for routine analysis of γ-conglutin from lupin seed extract. Copyright © 2017 Elsevier B.V. All rights reserved.

New applications of CRISPR/Cas9 system on mutant DNA detection.

PubMed

Jia, Chenqiang; Huai, Cong; Ding, Jiaqi; Hu, Lingna; Su, Bo; Chen, Hongyan; Lu, Daru

2018-01-30

The detection of mutant DNA is critical for precision medicine, but low-frequency DNA mutation is very hard to be determined. CRISPR/Cas9 is a robust tool for in vivo gene editing, and shows the potential for precise in vitro DNA cleavage. Here we developed a DNA mutation detection system based on CRISPR/Cas9 that can detect gene mutation efficiently even in a low-frequency condition. The system of CRISPR/Cas9 cleavage in vitro showed a high accuracy similar to traditional T7 endonuclease I (T7E1) assay in estimating mutant DNA proportion in the condition of normal frequency. The technology was further used for low-frequency mutant DNA detection of EGFR and HBB somatic mutations. To the end, Cas9 was employed to cleave the wild-type (WT) DNA and to enrich the mutant DNA. Using amplified fragment length polymorphism analysis (AFLPA) and Sanger sequencing, we assessed the sensitivity of CRISPR/Cas9 cleavage-based PCR, in which mutations at 1%-10% could be enriched and detected. When combined with blocker PCR, its sensitivity reached up to 0.1%. Our results suggested that this new application of CRISPR/Cas9 system is a robust and potential method for heterogeneous specimens in the clinical diagnosis and treatment management. Copyright © 2017 Elsevier B.V. All rights reserved.

Precise comparisons of bottom-pressure and altimetric ocean tides

NASA Astrophysics Data System (ADS)

Ray, R. D.

2013-09-01

A new set of pelagic tide determinations is constructed from seafloor pressure measurements obtained at 151 sites in the deep ocean. To maximize precision of estimated tides, only stations with long time series are used; median time series length is 567 days. Geographical coverage is considerably improved by use of the international tsunami network, but coverage in the Indian Ocean and South Pacific is still weak. As a tool for assessing global ocean tide models, the data set is considerably more reliable than older data sets: the root-mean-square difference with a recent altimetric tide model is approximately 5 mm for the M2 constituent. Precision is sufficiently high to allow secondary effects in altimetric and bottom-pressure tide differences to be studied. The atmospheric tide in bottom pressure is clearly detected at the S1, S2, and T2 frequencies. The altimetric tide model is improved if satellite altimetry is corrected for crustal loading by the atmospheric tide. Models of the solid body tide can also be constrained. The free core-nutation effect in the K1 Love number is easily detected, but the overall estimates are not as accurate as a recent determination with very long baseline interferometry.

Precise Comparisons of Bottom-Pressure and Altimetric Ocean Tides

NASA Technical Reports Server (NTRS)

Ray, Richard D.

2013-01-01

A new set of pelagic tide determinations is constructed from seafloor pressure measurements obtained at 151 sites in the deep ocean. To maximize precision of estimated tides, only stations with long time series are used; median time series length is 567 days. Geographical coverage is considerably improved by use of the international tsunami network, but coverage in the Indian Ocean and South Pacific is still weak. As a tool for assessing global ocean tide models, the data set is considerably more reliable than older data sets : the root-mean-square difference with a recent altimetric tide model is approximately 5 mm for the M2 constituent. Precision is sufficiently high to allow secondary effects in altimetric and bottom-pressure tide differences to be studied. The atmospheric tide in bottom pressure is clearly detected at the S1, S2, and T2 frequencies. The altimetric tide model is improved if satellite altimetry is corrected for crustal loading by the atmospheric tide. Models of the solid body tide can also be constrained. The free corenutation effect in the K1 Love number is easily detected, but the overall estimates are not as accurate as a recent determination with very long baseline interferometry.

Precise fiber length measurement using harmonic detection of phase-locked cavity modes

NASA Astrophysics Data System (ADS)

Terra, Osama

2018-06-01

In this paper, precise length measurements of optical fibers are performed by employing harmonic detection of the pulse-train frequency of a passively mode-locked fiber laser. This frequency is proportional to the length of the laser cavity in which the measured fiber is installed. Our proposed technique enables length measurement of long fibers from 1 to 40 km with precision from 0.4 to 8 mm and short fibers of few meters with precision as low as 26 μm. Such superior precision is achieved not only by the selection of higher harmonics of up to 1410, but also by the careful control of the wavelength at which the passive mode-locking occur, because of the broadband nature of the used gain medium.

High-precision half-life determination for the superallowed β+ emitter Ga62

NASA Astrophysics Data System (ADS)

Grinyer, G. F.; Finlay, P.; Svensson, C. E.; Ball, G. C.; Leslie, J. R.; Austin, R. A. E.; Bandyopadhyay, D.; Chaffey, A.; Chakrawarthy, R. S.; Garrett, P. E.; Hackman, G.; Hyland, B.; Kanungo, R.; Leach, K. G.; Mattoon, C. M.; Morton, A. C.; Pearson, C. J.; Phillips, A. A.; Ressler, J. J.; Sarazin, F.; Savajols, H.; Schumaker, M. A.; Wong, J.

2008-01-01

The half-life of the superallowed β+ emitter Ga62 has been measured at TRIUMF's Isotope Separator and Accelerator facility using a fast-tape-transport system and 4π continuous-flow gas proportional counter to detect the positrons from the decay of Ga62 to the daughter Zn62. The result, T1/2=116.100±0.025 ms, represents the most precise measurement to date (0.022%) for any superallowed β-decay half-life. When combined with six previous measurements of the Ga62 half-life, a new world average of T1/2=116.121±0.021 ms is obtained. This new half-life measurement results in a 20% improvement in the precision of the Ga62 superallowed ft value while reducing its mean by 0.9σ to ft=3074.3(12) s. The impact of this half-life measurement on precision tests of the CVC hypothesis and isospin symmetry breaking corrections for A⩾62 superallowed decays is discussed.

Investigating light curve modulation via kernel smoothing. I. Application to 53 fundamental mode and first-overtone Cepheids in the LMC

NASA Astrophysics Data System (ADS)

Süveges, Maria; Anderson, Richard I.

2018-03-01

Context. Recent studies have revealed a hitherto unknown complexity of Cepheid pulsations by discovering irregular modulated variability using photometry, radial velocities, and interferometry. Aim. We aim to perform a statistically rigorous search and characterization of such phenomena in continuous time, applying it to 53 classical Cepheids from the OGLE-III catalog. Methods: We have used local kernel regression to search for both period and amplitude modulations simultaneously in continuous time and to investigate their detectability. We determined confidence intervals using parametric and non-parametric bootstrap sampling to estimate significance, and investigated multi-periodicity using a modified pre-whitening approach that relies on time-dependent light curve parameters. Results: We find a wide variety of period and amplitude modulations and confirm that first overtone pulsators are less stable than fundamental mode Cepheids. Significant temporal variations in period are more frequently detected than those in amplitude. We find a range of modulation intensities, suggesting that both amplitude and period modulations are ubiquitous among Cepheids. Over the 12-year baseline offered by OGLE-III, we find that period changes are often nonlinear, sometimes cyclic, suggesting physical origins beyond secular evolution. Our method detects modulations (period and amplitude) more efficiently than conventional methods that are reliant on certain features in the Fourier spectrum, and pre-whitens time series more accurately than using constant light curve parameters, removing spurious secondary peaks effectively. Conclusions: Period and amplitude modulations appear to be ubiquitous among Cepheids. Current detectability is limited by observational cadence and photometric precision: detection of amplitude modulation below 3 mmag requires space-based facilities. Recent and ongoing space missions (K2, BRITE, MOST, CoRoT) as well as upcoming ones (TESS, PLATO) will significantly improve detectability of fast modulations, such as cycle-to-cycle variations, by providing high-cadence high-precision photometry. High-quality long-term ground-based photometric time series will remain crucial to study longer-term modulations and to disentangle random fluctuations from secular evolution.

Benford's law gives better scaling exponents in phase transitions of quantum XY models.

PubMed

Rane, Ameya Deepak; Mishra, Utkarsh; Biswas, Anindya; Sen De, Aditi; Sen, Ujjwal

2014-08-01

Benford's law is an empirical law predicting the distribution of the first significant digits of numbers obtained from natural phenomena and mathematical tables. It has been found to be applicable for numbers coming from a plethora of sources, varying from seismographic, biological, financial, to astronomical. We apply this law to analyze the data obtained from physical many-body systems described by the one-dimensional anisotropic quantum XY models in a transverse magnetic field. We detect the zero-temperature quantum phase transition and find that our method gives better finite-size scaling exponents for the critical point than many other known scaling exponents using measurable quantities like magnetization, entanglement, and quantum discord. We extend our analysis to the same system but at finite temperature and find that it also detects the finite-temperature phase transition in the model. Moreover, we compare the Benford distribution analysis with the same obtained from the uniform and Poisson distributions. The analysis is furthermore important in that the high-precision detection of the cooperative physical phenomena is possible even from low-precision experimental data.

Geodynamics and temporal variations in the gravity field

NASA Technical Reports Server (NTRS)

Mcadoo, D. C.; Wagner, C. A.

1989-01-01

Just as the Earth's surface deforms tectonically, so too does the gravity field evolve with time. Now that precise geodesy is yielding observations of these deformations it is important that concomitant, temporal changes in the gravity field be monitored. Although these temporal changes are minute they are observable: changes in the J2 component of the gravity field were inferred from satellite (LAGEOS) tracking data; changes in other components of the gravity field would likely be detected by Geopotential Research Mission (GRM), a proposed but unapproved NASA gravity field mission. Satellite gradiometers were also proposed for high-precision gravity field mapping. Using simple models of geodynamic processes such as viscous postglacial rebound of the solid Earth, great subduction zone earthquakes and seasonal glacial mass fluctuations, we predict temporal changes in gravity gradients at spacecraft altitudes. It was found that these proposed gravity gradient satellite missions should have sensitivities equal to or better than 10(exp -4) E in order to reliably detect these changes. It was also found that satellite altimetry yields little promise of useful detection of time variations in gravity.

Precise fabrication of a 5 nm graphene nanopore with a helium ion microscope for biomolecule detection

NASA Astrophysics Data System (ADS)

Deng, Yunsheng; Huang, Qimeng; Zhao, Yue; Zhou, Daming; Ying, Cuifeng; Wang, Deqiang

2017-01-01

We report a scalable method to fabricate high-quality graphene nanopores for biomolecule detection using a helium ion microscope (HIM). HIM milling shows promising capabilities for precisely controlling the size and shape, and may allow for the potential production of nanopores at wafer scale. Nanopores could be fabricated at different sizes ranging from 5 to 30 nm in diameter in few minutes. Compared with the current solid-state nanopore fabrication techniques, e.g. transmission electron microscopy, HIM is fast. Furthermore, we investigated the exposure-time dependence of graphene nanopore formation: the rate of pore expansion did not follow a simple linear relationship with exposure time, but a fast expansion rate at short exposure time and a slow rate at long exposure time. In addition, we performed biomolecule detection with our patterned graphene nanopore. The ionic current signals induced by 20-base single-stranded DNA homopolymers could be used as a basis for homopolymer differentiation. However, the charge interaction of homopolymer chains with graphene nanopores, and the conformations of homopolymer chains need to be further considered to improve the accuracy of discrimination.

In-situ detection of convection and rotation striations by growth interface electromotive force spectrum

NASA Astrophysics Data System (ADS)

Zhu, Yunzhong; Tang, Feng; Yang, Xin; Yang, Mingming; Ma, Decai; Zhang, Xiaoyue; Liu, Yang; Lin, Shaopeng; Wang, Biao

2018-04-01

Nanoscale growth striations, induced by the crystal rotation and melt convection, are in-situ detected by the growth interface electromotive force (GEMF) spectrum during Czochralski (CZ) crystal growth. Specifically, the intensity and period of rotation and convection striations could be precisely revealed under different rotation rates. This is because the GEMF spectrum is affected by the combination effort of temperature difference in crystal rotation path and the melt flow in growth interface. Furthermore, the spectrum analysis (Fourier transform) reveals remarkable characteristics of periodic flow oscillation. More interestingly, in different rotation rates, the corresponding convection period and intensity show particular regularity that could barely be observed in semitransparent and high-temperature melt. Therefore, the GEMF spectrum reflects the subtle changes of a growing crystal that is far beyond the detecting precision of sensors in current CZ equipment. On the basis of this paper and our previous work, the real-time feedback of multiscale striations is established. GEMF spectrum could be a promising approach to reveal striation formation mechanism and optimize crystal quality.

Rapid determination of five antibiotic residues in swine wastewater by online solid-phase extraction-high performance liquid chromatography-tandem mass spectrometry.

PubMed

Tagiri-Endo, Misako; Suzuki, Shigeru; Nakamura, Tomoyuki; Hatakeyama, Takashi; Kawamukai, Kazuo

2009-02-01

A simple and quick online solid-phase extraction (SPE) coupled to liquid chromatography (LC)/tandem mass spectrometry (MS/MS) for the determination of the five antibiotics (florfenicol, FF; lincomycin, LCM; oxytetracyclin, OTC; tylosin, TS; valnemulin, VLM) in swine wastewater has been developed. After filtration, aliquots (100 microl) of wastewater samples were directly injected to a column-switching LC system. Some matrix interference was removed by washing up SPE column with 0.2% formic acid solution and acetonitrile. Antibiotics eluted from SPE column were separated on analytical column by converting switching valve and were detected by MS/MS. Calibration curves using the method of standard addition had very good correlation coefficients (r > 0.99) in the range of 0.1 to 2 ng/ml. The intra-day precision of the method was less than 12% and the inter-day precision was between 6 to 17%. The detection limits were 0.01-0.1 ng/ml. When this method was applied to wastewater samples in swine facilities, four compounds (LCM, OTC, TS, and VLM) were detected.

High precision measurements of 26Naβ- decay

NASA Astrophysics Data System (ADS)

Grinyer, G. F.; Svensson, C. E.; Andreoiu, C.; Andreyev, A. N.; Austin, R. A.; Ball, G. C.; Chakrawarthy, R. S.; Finlay, P.; Garrett, P. E.; Hackman, G.; Hardy, J. C.; Hyland, B.; Iacob, V. E.; Koopmans, K. A.; Kulp, W. D.; Leslie, J. R.; MacDonald, J. A.; Morton, A. C.; Ormand, W. E.; Osborne, C. J.; Pearson, C. J.; Phillips, A. A.; Sarazin, F.; Schumaker, M. A.; Scraggs, H. C.; Schwarzenberg, J.; Smith, M. B.; Valiente-Dobón, J. J.; Waddington, J. C.; Wood, J. L.; Zganjar, E. F.

2005-04-01

High-precision measurements of the half-life and β-branching ratios for the β- decay of 26Na to 26Mg have been measured in β-counting and γ-decay experiments, respectively. A 4π proportional counter and fast tape transport system were employed for the half-life measurement, whereas the γ rays emitted by the daughter nucleus 26Mg were detected with the 8π γ-ray spectrometer, both located at TRIUMF's isotope separator and accelerator radioactive beam facility. The half-life of 26Na was determined to be T1/2=1.07128±0.00013±0.00021s, where the first error is statistical and the second systematic. The logft values derived from these experiments are compared with theoretical values from a full sd-shell model calculation.

A Review of Optical NDT Technologies

PubMed Central

Zhu, Yong-Kai; Tian, Gui-Yun; Lu, Rong-Sheng; Zhang, Hong

2011-01-01

Optical non-destructive testing (NDT) has gained more and more attention in recent years, mainly because of its non-destructive imaging characteristics with high precision and sensitivity. This paper provides a review of the main optical NDT technologies, including fibre optics, electronic speckle, infrared thermography, endoscopic and terahertz technology. Among them, fibre optics features easy integration and embedding, electronic speckle focuses on whole-field high precision detection, infrared thermography has unique advantages for tests of combined materials, endoscopic technology provides images of the internal surface of the object directly, and terahertz technology opens a new direction of internal NDT because of its excellent penetration capability to most of non-metallic materials. Typical engineering applications of these technologies are illustrated, with a brief introduction of the history and discussion of recent progress. PMID:22164045

Radial Velocity Detection of Extra-Solar Planetary Systems

NASA Technical Reports Server (NTRS)

Cochran, William D.

2004-01-01

This NASA Origins Program grant supported four closely related research programs at The University of Texas at Austin: 1) The McDonald Observatory Planetary Search (MOPS) Program, using the McDonald Observatory 2.7m Harlan Smith telescope and its 2dcoud6 spectrometer, 2) A high-precision radial-velocity survey of Hyades dwarfs, using the Keck telescope and its HIRES spectrograph, 3) A program at McDonald Observatory to obtain spectra of the parent stars of planetary systems at R = 210,000, and 4) the start of high precision radial velocity surveys using the Hobby-Eberly Telescope. The most important results from NASA support of these research programs are described below. A list of all papers published under support of this grant is included at the end.

The simple determination method for anthocyanidin aglycones in fruits using ultra-high-performance liquid chromatography.

PubMed

Shim, You-Shin; Yoon, Won-Jin; Kim, Dong-Man; Watanabe, Masaki; Park, Hyun-Jin; Jang, Hae Won; Lee, Jangho; Ha, Jaeho

2015-01-01

The simple determination method for anthocyanidin aglycones in fruits using ultra-high-performance liquid chromatography (UHPLC) coupled with the heating-block acidic hydrolysis method was validated through the precision, accuracy and linearity. The UHPLC separation was performed on a reversed-phase C18 column (particle size 2 μm, i.d. 2 mm, length 100 mm) with a photodiode-array detector. The limits of detection and quantification of the UHPLC analyses were 0.09 and 0.29 mg/kg for delphinidin, 0.08 and 0.24 mg/kg for cyanidin, 0.09 and 0.26 mg/kg for petunidin, 0.14 and 0.42 mg/kg for pelargonidin, 0.16 and 0.48 mg/kg for peonidin and 0.30 and 0.91 mg/kg for malvidin, respectively. The intra- and inter-day precisions of individual anthocyanidin aglycones were <10.3%. All calibration curves exhibited good linearity (r = 0.999) within the tested ranges. The total run time of UHPLC was 8 min. The simple preparation method with UHPLC detection in this study presented herein significantly improved the speed and the simplicity for preparation step of delphinidin, cyanidin, petunidin, pelargonidin, peonidin and malvidin in fruits. Especially, the UHPLC detection exhibited good resolution in spite of shorter run time about four times than conventional HPLC detection. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Event identification for KM3NeT/ARCA

NASA Astrophysics Data System (ADS)

Heid, Thomas; KM3NeT Collaboration

2017-09-01

KM3NeT is a large research infrastructure consisting of a network of deep-sea neutrino telescopes. KM3NeT/ARCA will be the instrument detecting high-energy neutrinos with energies above 100 TeV. This instrument gives a new opportunity to observe the neutrino sky with very high angular resolution to be able to detect neutrino point sources. Furthermore it will be possible to probe the flavour composition of neutrino fluxes, and hence production mechanisms, with so-far unreached precision. Neutrinos produce different event topologies in the detector according to their flavour, interaction channel and deposited energy. Machine-learning algorithms are able to learn features of topologies to discriminate them. In previous analyses only two event types were regarded, namely the shower and track topology. With good timing resolution and precise reconstruction algorithms it is possible to separate into more event types, for example the double bang topology produced by tau neutrinos. The final goal is to distinguish all three neutrino flavors as much as possible. To resolve this issue the KM3NeT collaboration uses deep neural networks trained with Monte Carlo events of all neutrino types. This contribution shows the ability of KM3NeT/ARCA to classify events in more than two neutrino event topologies. Furthermore, the borders between detectable classes are shown, such as the minimum distance the tau has to travel before decaying into a tau neutrino to be detected as double bang event.

A novel algorithm for detecting active propulsion in wheelchair users following spinal cord injury.

PubMed

Popp, Werner L; Brogioli, Michael; Leuenberger, Kaspar; Albisser, Urs; Frotzler, Angela; Curt, Armin; Gassert, Roger; Starkey, Michelle L

2016-03-01

Physical activity in wheelchair-bound individuals can be assessed by monitoring their mobility as this is one of the most intense upper extremity activities they perform. Current accelerometer-based approaches for describing wheelchair mobility do not distinguish between self- and attendant-propulsion and hence may overestimate total physical activity. The aim of this study was to develop and validate an inertial measurement unit based algorithm to monitor wheel kinematics and the type of wheelchair propulsion (self- or attendant-) within a "real-world" situation. Different sensor set-ups were investigated, ranging from a high precision set-up including four sensor modules with a relatively short measurement duration of 24 h, to a less precise set-up with only one module attached at the wheel exceeding one week of measurement because the gyroscope of the sensor was turned off. The "high-precision" algorithm distinguished self- and attendant-propulsion with accuracy greater than 93% whilst the long-term measurement set-up showed an accuracy of 82%. The estimation accuracy of kinematic parameters was greater than 97% for both set-ups. The possibility of having different sensor set-ups allows the use of the inertial measurement units as high precision tools for researchers as well as unobtrusive and simple tools for manual wheelchair users. Copyright © 2016 IPEM. Published by Elsevier Ltd. All rights reserved.

Size-exclusion chromatography for the determination of the boiling point distribution of high-boiling petroleum fractions.

PubMed

Boczkaj, Grzegorz; Przyjazny, Andrzej; Kamiński, Marian

2015-03-01

The paper describes a new procedure for the determination of boiling point distribution of high-boiling petroleum fractions using size-exclusion chromatography with refractive index detection. Thus far, the determination of boiling range distribution by chromatography has been accomplished using simulated distillation with gas chromatography with flame ionization detection. This study revealed that in spite of substantial differences in the separation mechanism and the detection mode, the size-exclusion chromatography technique yields similar results for the determination of boiling point distribution compared with simulated distillation and novel empty column gas chromatography. The developed procedure using size-exclusion chromatography has a substantial applicability, especially for the determination of exact final boiling point values for high-boiling mixtures, for which a standard high-temperature simulated distillation would have to be used. In this case, the precision of final boiling point determination is low due to the high final temperatures of the gas chromatograph oven and an insufficient thermal stability of both the gas chromatography stationary phase and the sample. Additionally, the use of high-performance liquid chromatography detectors more sensitive than refractive index detection allows a lower detection limit for high-molar-mass aromatic compounds, and thus increases the sensitivity of final boiling point determination. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Detection of the barium daughter in 136Xe -->136Ba + 2e- by in situ single-molecule fluorescence imaging

NASA Astrophysics Data System (ADS)

Nygren, David

2015-10-01

To proceed toward effective ``discovery class'' ton-scale detectors in the search for neutrino-less double beta decay, a robust technique for rejection of all radioactivity-induced backgrounds is urgently needed. An efficient technique for detection of the barium daughter in the decay 136Xe -->136Ba + 2e- would provide a long-sought pathway toward this goal. Single-molecule fluorescent imaging appears to offer a new way to detect the barium daughter atom, which emerges naturally in an ionized state in pure xenon. A doubly charged barium ion can initiate a chelation process with a non-fluorescent precursor molecule, leading to a highly fluorescent complex. Repeated photo-excitation of the complex can reveal both presence and location of a single ionized atom with high precision and selectivity. Detection within the active volume of a xenon gas Time Projection Chamber operating at high pressure would be automatic, and with a capability for redundant confirmation.

A Smart Spoofing Face Detector by Display Features Analysis.

PubMed

Lai, ChinLun; Tai, ChiuYuan

2016-07-21

In this paper, a smart face liveness detector is proposed to prevent the biometric system from being "deceived" by the video or picture of a valid user that the counterfeiter took with a high definition handheld device (e.g., iPad with retina display). By analyzing the characteristics of the display platform and using an expert decision-making core, we can effectively detect whether a spoofing action comes from a fake face displayed in the high definition display by verifying the chromaticity regions in the captured face. That is, a live or spoof face can be distinguished precisely by the designed optical image sensor. To sum up, by the proposed method/system, a normal optical image sensor can be upgraded to a powerful version to detect the spoofing actions. The experimental results prove that the proposed detection system can achieve very high detection rate compared to the existing methods and thus be practical to implement directly in the authentication systems.

Performance of a high-sensitivity dedicated cardiac SPECT scanner for striatal uptake quantification in the brain based on analysis of projection data

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

Park, Mi-Ae; Moore, Stephen C.; McQuaid, Sarah J.

Purpose: The authors have previously reported the advantages of high-sensitivity single-photon emission computed tomography (SPECT) systems for imaging structures located deep inside the brain. DaTscan (Isoflupane I-123) is a dopamine transporter (DaT) imaging agent that has shown potential for early detection of Parkinson disease (PD), as well as for monitoring progression of the disease. Realizing the full potential of DaTscan requires efficient estimation of striatal uptake from SPECT images. They have evaluated two SPECT systems, a conventional dual-head gamma camera with low-energy high-resolution collimators (conventional) and a dedicated high-sensitivity multidetector cardiac imaging system (dedicated) for imaging tasks related to PD.more » Methods: Cramer-Rao bounds (CRB) on precision of estimates of striatal and background activity concentrations were calculated from high-count, separate acquisitions of the compartments (right striata, left striata, background) of a striatal phantom. CRB on striatal and background activity concentration were calculated from essentially noise-free projection datasets, synthesized by scaling and summing the compartment projection datasets, for a range of total detected counts. They also calculated variances of estimates of specific-to-nonspecific binding ratios (BR) and asymmetry indices from these values using propagation of error analysis, as well as the precision of measuring changes in BR on the order of the average annual decline in early PD. Results: Under typical clinical conditions, the conventional camera detected 2 M counts while the dedicated camera detected 12 M counts. Assuming a normal BR of 5, the standard deviation of BR estimates was 0.042 and 0.021 for the conventional and dedicated system, respectively. For an 8% decrease to BR = 4.6, the signal-to-noise ratio were 6.8 (conventional) and 13.3 (dedicated); for a 5% decrease, they were 4.2 (conventional) and 8.3 (dedicated). Conclusions: This implies that PD can be detected earlier with the dedicated system than with the conventional system; therefore, earlier identification of PD progression should be possible with the high-sensitivity dedicated SPECT camera.« less

Automatic Detection and Positioning of Ground Control Points Using TerraSAR-X Multiaspect Acquisitions

NASA Astrophysics Data System (ADS)

Montazeri, Sina; Gisinger, Christoph; Eineder, Michael; Zhu, Xiao xiang

2018-05-01

Geodetic stereo Synthetic Aperture Radar (SAR) is capable of absolute three-dimensional localization of natural Persistent Scatterer (PS)s which allows for Ground Control Point (GCP) generation using only SAR data. The prerequisite for the method to achieve high precision results is the correct detection of common scatterers in SAR images acquired from different viewing geometries. In this contribution, we describe three strategies for automatic detection of identical targets in SAR images of urban areas taken from different orbit tracks. Moreover, a complete work-flow for automatic generation of large number of GCPs using SAR data is presented and its applicability is shown by exploiting TerraSAR-X (TS-X) high resolution spotlight images over the city of Oulu, Finland and a test site in Berlin, Germany.

Determination of limonin in grapefruit juice and other citrus juices by high-performance liquid chromatography.

PubMed

Van Beek, T A; Blaakmeer, A

1989-03-03

A method has been developed for the quantitation of the bitter component limonin in grapefruit juice and other citrus juices. The sample clean-up consisted of centrifugation, filtration and a selective, rapid and reproducible purification with a C2 solid-phase extraction column. The limonin concentration was determined by high-performance liquid chromatography on a C18 column with UV detection at 210 nm. A linear response was obtained from 0.0 to 45 ppm limonin. The minimum detectable amount was 2 ng. The minimum concentration which was detected without concentration with good precision was 0.1 ppm. The method was also used for the determination of limonin in different types of oranges, including navel oranges, mandarins, lemons, limes, pomelos and uglis.

Accurate analysis of parabens in human urine using isotope-dilution ultrahigh-performance liquid chromatography-high resolution mass spectrometry.

PubMed

Zhou, Hui-Ting; Chen, Hsin-Chang; Ding, Wang-Hsien

2018-02-20

An analytical method that utilizes isotope-dilution ultrahigh-performance liquid chromatography coupled with hybrid quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS or called UHPLC-HRMS) was developed, and validated to be highly precise and accurate for the detection of nine parabens (methyl-, ethyl-, propyl-, isopropyl-, butyl-, isobutyl-, pentyl-, hexyl-, and benzyl-parabens) in human urine samples. After sample preparation by ultrasound-assisted emulsification microextraction (USAEME), the extract was directly injected into UHPLC-HRMS. By using negative electrospray ionization in the multiple reaction monitoring (MRM) mode and measuring the peak area ratios of both the natural and the labeled-analogues in the samples and calibration standards, the target analytes could be accurately identified and quantified. Another use for the labeled-analogues was to correct for systematic errors associated with the analysis, such as the matrix effect and other variations. The limits of quantitation (LOQs) were ranging from 0.3 to 0.6 ng/mL. High precisions for both repeatability and reproducibility were obtained ranging from 1 to 8%. High trueness (mean extraction recovery, or called accuracy) ranged from 93 to 107% on two concentration levels. According to preliminary results, the total concentrations of four most detected parabens (methyl-, ethyl-, propyl- and butyl-) ranged from 0.5 to 79.1 ng/mL in male urine samples, and from 17 to 237 ng/mL in female urine samples. Interestingly, two infrequently detected pentyl- and hexyl-parabens were found in one of the male samples in this study. Copyright © 2017 Elsevier B.V. All rights reserved.

High-precision photometry by telescope defocussing - VI. WASP-24, WASP-25 and WASP-26

NASA Astrophysics Data System (ADS)

Southworth, John; Hinse, T. C.; Burgdorf, M.; Calchi Novati, S.; Dominik, M.; Galianni, P.; Gerner, T.; Giannini, E.; Gu, S.-H.; Hundertmark, M.; Jørgensen, U. G.; Juncher, D.; Kerins, E.; Mancini, L.; Rabus, M.; Ricci, D.; Schäfer, S.; Skottfelt, J.; Tregloan-Reed, J.; Wang, X.-B.; Wertz, O.; Alsubai, K. A.; Andersen, J. M.; Bozza, V.; Bramich, D. M.; Browne, P.; Ciceri, S.; D'Ago, G.; Damerdji, Y.; Diehl, C.; Dodds, P.; Elyiv, A.; Fang, X.-S.; Finet, F.; Figuera Jaimes, R.; Hardis, S.; Harpsøe, K.; Jessen-Hansen, J.; Kains, N.; Kjeldsen, H.; Korhonen, H.; Liebig, C.; Lund, M. N.; Lundkvist, M.; Mathiasen, M.; Penny, M. T.; Popovas, A.; Prof., S.; Rahvar, S.; Sahu, K.; Scarpetta, G.; Schmidt, R. W.; Schönebeck, F.; Snodgrass, C.; Street, R. A.; Surdej, J.; Tsapras, Y.; Vilela, C.

2014-10-01

We present time series photometric observations of 13 transits in the planetary systems WASP-24, WASP-25 and WASP-26. All three systems have orbital obliquity measurements, WASP-24 and WASP-26 have been observed with Spitzer, and WASP-25 was previously comparatively neglected. Our light curves were obtained using the telescope-defocussing method and have scatters of 0.5-1.2 mmag relative to their best-fitting geometric models. We use these data to measure the physical properties and orbital ephemerides of the systems to high precision, finding that our improved measurements are in good agreement with previous studies. High-resolution Lucky Imaging observations of all three targets show no evidence for faint stars close enough to contaminate our photometry. We confirm the eclipsing nature of the star closest to WASP-24 and present the detection of a detached eclipsing binary within 4.25 arcmin of WASP-26.

National and International Security Applications of Cryogenic Detectors—Mostly Nuclear Safeguards

NASA Astrophysics Data System (ADS)

Rabin, Michael W.

2009-12-01

As with science, so with security—in both arenas, the extraordinary sensitivity of cryogenic sensors enables high-confidence detection and high-precision measurement even of the faintest signals. Science applications are more mature, but several national and international security applications have been identified where cryogenic detectors have high potential payoff. International safeguards and nuclear forensics are areas needing new technology and methods to boost speed, sensitivity, precision and accuracy. Successfully applied, improved nuclear materials analysis will help constrain nuclear materials diversion pathways and contribute to treaty verification. Cryogenic microcalorimeter detectors for X-ray, gamma-ray, neutron, and alpha-particle spectrometry are under development with these aims in mind. In each case the unsurpassed energy resolution of microcalorimeters reveals previously invisible spectral features of nuclear materials. Preliminary results of quantitative analysis indicate substantial improvements are still possible, but significant work will be required to fully understand the ultimate performance limits.

Quantitative determination of insulin entrapment efficiency in triblock copolymeric nanoparticles by high-performance liquid chromatography.

PubMed

Xu, Xiongliang; Fu, Yao; Hu, Haiyan; Duan, Yourong; Zhang, Zhirong

2006-04-11

A rapid and effective isocratic chromatographic procedure was described in this paper for the determination of insulin entrapment efficiency (EE) in triblock copolymeric nanoparticles using reversed-phase high-performance liquid chromatography (RP-HPLC) with an ultraviolet/visible detector at low flow rate. The method has been developed on a Shimadzu Shim-pack VP-ODS column (150 mm x 4.6 mm, 5 microm, Chiyoda-Ku, Tokyo, Japan) using a mixture of 0.2 M sodium sulfate anhydrous solution adjusted to pH 2.3 with phosphoric acid and acetonitrile (73:27, v/v) as mobile phase at the flow rate of 0.8 ml min(-1) and a 214 nm detection. The method was validated in terms of selectivity, linearity, precision, accuracy, solution stability, limit of detection (LOD) and limit of quantification (LOQ). The calibration curve was linear in the concentration range of 2.0-500.0 microg ml(-1), and the limits of detection and quantitation were 8 and 20 ng, respectively. The mean recovery of insulin from spiked samples, in a concentration range of 8-100 microg ml(-1), was 98.96% (R.S.D.= 2.51%, n = 9). The intra- and inter-assay coefficients of variation were less than 2.24%. The proposed method has the advantages of simple pretreatment, rapid isolation, high specificity and precision, which can be used for direct analysis of insulin in commercially available raw materials, formulations of nanoparticles, and drug release as well as stability studies.

Staircase-scene-based nonuniformity correction in aerial point target detection systems.

PubMed

Huo, Lijun; Zhou, Dabiao; Wang, Dejiang; Liu, Rang; He, Bin

2016-09-01

Focal-plane arrays (FPAs) are often interfered by heavy fixed-pattern noise, which severely degrades the detection rate and increases the false alarms in airborne point target detection systems. Thus, high-precision nonuniformity correction is an essential preprocessing step. In this paper, a new nonuniformity correction method is proposed based on a staircase scene. This correction method can compensate for the nonlinear response of the detector and calibrate the entire optical system with computational efficiency and implementation simplicity. Then, a proof-of-concept point target detection system is established with a long-wave Sofradir FPA. Finally, the local standard deviation of the corrected image and the signal-to-clutter ratio of the Airy disk of a Boeing B738 are measured to evaluate the performance of the proposed nonuniformity correction method. Our experimental results demonstrate that the proposed correction method achieves high-quality corrections.

ECG signal analysis through hidden Markov models.

PubMed

Andreão, Rodrigo V; Dorizzi, Bernadette; Boudy, Jérôme

2006-08-01

This paper presents an original hidden Markov model (HMM) approach for online beat segmentation and classification of electrocardiograms. The HMM framework has been visited because of its ability of beat detection, segmentation and classification, highly suitable to the electrocardiogram (ECG) problem. Our approach addresses a large panel of topics some of them never studied before in other HMM related works: waveforms modeling, multichannel beat segmentation and classification, and unsupervised adaptation to the patient's ECG. The performance was evaluated on the two-channel QT database in terms of waveform segmentation precision, beat detection and classification. Our waveform segmentation results compare favorably to other systems in the literature. We also obtained high beat detection performance with sensitivity of 99.79% and a positive predictivity of 99.96%, using a test set of 59 recordings. Moreover, premature ventricular contraction beats were detected using an original classification strategy. The results obtained validate our approach for real world application.

Large aperture and wide field of view space telescope for the detection of ultra high energy cosmic rays and neutrinos

NASA Astrophysics Data System (ADS)

Mazzinghi, Piero; Bratina, Vojko; Gambicorti, Lisa; Simonetti, Francesca; Zuccaro Marchi, Alessandro

2017-11-01

New technologies are proposed for large aperture and wide Field of View (FOV) space telescopes dedicated to detection of Ultra High Energy Cosmic Rays and Neutrinos flux, through observation of fluorescence traces in atmosphere and diffused Cerenkov signals. The presented advanced detection system is a spaceborne LEO telescope, with better performance than ground-based observatories, detecting up to 103 - 104 events/year. Different design approaches are implemented, all with very large FOV and focal surface detectors with sufficient segmentation and time resolution to allow precise reconstructions of the arrival direction. In particular, two Schmidt cameras are suggested as an appropriate solution to match most of the optical and technical requirements: large FOV, low f/#, reduction of stray light, optionally flat focal surface, already proven low-cost construction technologies. Finally, a preliminary proposal of a wideFOV retrofocus catadioptric telescope is explained.

Determination of sucralose in Splenda and a sugar-free beverage using high-performance anion-exchange chromatography with pulsed amperometric detection.

PubMed

Hanko, Valoran P; Rohrer, Jeffrey S

2004-07-14

Sucralose is a chlorinated carbohydrate nonnutritive sweetener of food and beverage products. The determination of sucralose in food and beverages is important to ensure consistency in product quality. Sucralose was determined in two commercial products without sample preparation using high-performance anion-exchange (HPAE) chromatography coupled with pulsed amperometric detection (PAD). Sucralose was determined with a 10 min isocratic separation. To determine sucralose and other carbohydrates (e.g., dextrose) simultaneously, a gradient separation was developed. The linear range of electrochemical response extended over 3 orders of magnitude, from 0.01 (LOD) to 40 microM (16 microg/mL; 25 microL injection). High precision, high spike recovery, and method ruggedness were observed for both samples.

New-style defect inspection system of film

NASA Astrophysics Data System (ADS)

Liang, Yan; Liu, Wenyao; Liu, Ming; Lee, Ronggang

2002-09-01

An inspection system has been developed for on-line detection of film defects, which bases on combination of photoelectric imaging and digital image processing. The system runs in high speed of maximum 60m/min. Moving film is illuminated by LED array which emits even infrared (peak wavelength λp=940nm), and infrared images are obtained with a high quality and high speed CCD camera. The application software based on Visual C++6.0 under Windows processes images in real time by means of such algorithms as median filter, edge detection and projection, etc. The system is made up of four modules, which are introduced in detail in the paper. On-line experiment results shows that the inspection system can recognize defects precisely in high speed and run reliably in practical application.

ALHAT System Validation

NASA Technical Reports Server (NTRS)

Brady, Tye; Bailey, Erik; Crain, Timothy; Paschall, Stephen

2011-01-01

NASA has embarked on a multiyear technology development effort to develop a safe and precise lunar landing capability. The Autonomous Landing and Hazard Avoidance Technology (ALHAT) Project is investigating a range of landing hazard detection methods while developing a hazard avoidance capability to best field test the proper set of relevant autonomous GNC technologies. Ultimately, the advancement of these technologies through the ALHAT Project will provide an ALHAT System capable of enabling next generation lunar lander vehicles to globally land precisely and safely regardless of lighting condition. This paper provides an overview of the ALHAT System and describes recent validation experiments that have advanced the highly capable GNC architecture.

Emission quantification using the tracer gas dispersion method: The influence of instrument, tracer gas species and source simulation.

PubMed

Delre, Antonio; Mønster, Jacob; Samuelsson, Jerker; Fredenslund, Anders M; Scheutz, Charlotte

2018-09-01

The tracer gas dispersion method (TDM) is a remote sensing method used for quantifying fugitive emissions by relying on the controlled release of a tracer gas at the source, combined with concentration measurements of the tracer and target gas plumes. The TDM was tested at a wastewater treatment plant for plant-integrated methane emission quantification, using four analytical instruments simultaneously and four different tracer gases. Measurements performed using a combination of an analytical instrument and a tracer gas, with a high ratio between the tracer gas release rate and instrument precision (a high release-precision ratio), resulted in well-defined plumes with a high signal-to-noise ratio and a high methane-to-tracer gas correlation factor. Measured methane emission rates differed by up to 18% from the mean value when measurements were performed using seven different instrument and tracer gas combinations. Analytical instruments with a high detection frequency and good precision were established as the most suitable for successful TDM application. The application of an instrument with a poor precision could only to some extent be overcome by applying a higher tracer gas release rate. A sideward misplacement of the tracer gas release point of about 250m resulted in an emission rate comparable to those obtained using a tracer gas correctly simulating the methane emission. Conversely, an upwind misplacement of about 150m resulted in an emission rate overestimation of almost 50%, showing the importance of proper emission source simulation when applying the TDM. Copyright © 2018 Elsevier B.V. All rights reserved.

Advancing Precision Nuclear Medicine and Molecular Imaging for Lymphoma.

PubMed

Wright, Chadwick L; Maly, Joseph J; Zhang, Jun; Knopp, Michael V

2017-01-01

PET with fluorodeoxyglucose F 18 ( 18 F FDG-PET) is a meaningful biomarker for the detection, targeted biopsy, and treatment of lymphoma. This article reviews the evolution of 18 F FDG-PET as a putative biomarker for lymphoma and addresses the current capabilities, challenges, and opportunities to enable precision medicine practices for lymphoma. Precision nuclear medicine is driven by new imaging technologies and methodologies to more accurately detect malignant disease. Although quantitative assessment of response is limited, such technologies will enable a more precise metabolic mapping with much higher definition image detail and thus may make it a robust and valid quantitative response assessment methodology. Copyright © 2016 Elsevier Inc. All rights reserved.

Molecular imprinting ratiometric fluorescence sensor for highly selective and sensitive detection of phycocyanin.

PubMed

Wang, Xiaoyan; Yu, Jialuo; Kang, Qi; Shen, Dazhong; Li, Jinhua; Chen, Lingxin

2016-03-15

A facile strategy was developed to prepare molecular imprinting ratiometric fluorescence sensor for highly selective and sensitive detection of phycocyanin (PC) based on fluorescence resonance energy transfer (FRET), via a sol-gel polymerization process using nitrobenzoxadiazole (NBD) as fluorescent signal source. The ratio of two fluorescence peak emission intensities of NBD and PC was utilized to determine the concentration of PC, which could effectively reduce the background interference and fluctuation of diverse conditions. As a result, this sensor obtained high sensitivity with a low detection limit of 0.14 nM within 6 min, and excellent recognition specificity for PC over its analogues with a high imprinting factor of 9.1. Furthermore, the sensor attained high recoveries in the range of 93.8-110.2% at three spiking levels of PC, with precisions below 4.7% in seawater and lake water samples. The developed sensor strategy demonstrated simplicity, reliability, rapidity, high selectivity and high sensitivity, proving to be a feasible way to develop high efficient fluorescence sensors and thus potentially applicable for ultratrace analysis of complicated matrices. Copyright © 2015 Elsevier B.V. All rights reserved.

Quantitation of five organophosphorus nerve agent metabolites in serum using hydrophilic interaction liquid chromatography and tandem mass spectrometry

PubMed Central

Hamelin, Elizabeth I.; Schulze, Nicholas D.; Shaner, Rebecca L.; Coleman, Rebecca M.; Lawrence, Richard J.; Crow, Brian S.; Jakubowski, E. M.; Johnson, Rudolph C.

2015-01-01

Although nerve agent use is prohibited, concerns remain for human exposure to nerve agents during decommissioning, research, and warfare. Exposure can be detected through the analysis of the hydrolysis products in urine as well as blood. An analytical method to detect exposure to five nerve agents, including VX, VR (Russian VX), GB (sarin), GD (soman) and GF (cyclosarin), through the analysis of the hydrolysis products, which are the primary metabolites, in serum has been developed and characterized. This method uses solid phase extraction coupled with high performance liquid chromatography for separation and isotopic dilution tandem mass spectrometry for detection. An uncommon buffer of ammonium fluoride was used to enhance ionization and improve sensitivity when coupled with hydrophilic interaction liquid chromatography resulting in detection limits from 0.3–0.5 ng/mL. The assessment of two quality control samples demonstrated high accuracy (101–105%) and high precision (5–8%) for the detection of these five nerve agent hydrolysis products in serum. PMID:24633507

Time-Gated Orthogonal Scanning Automated Microscopy (OSAM) for High-speed Cell Detection and Analysis

NASA Astrophysics Data System (ADS)

Lu, Yiqing; Xi, Peng; Piper, James A.; Huo, Yujing; Jin, Dayong

2012-11-01

We report a new development of orthogonal scanning automated microscopy (OSAM) incorporating time-gated detection to locate rare-event organisms regardless of autofluorescent background. The necessity of using long-lifetime (hundreds of microseconds) luminescent biolabels for time-gated detection implies long integration (dwell) time, resulting in slow scan speed. However, here we achieve high scan speed using a new 2-step orthogonal scanning strategy to realise on-the-fly time-gated detection and precise location of 1-μm lanthanide-doped microspheres with signal-to-background ratio of 8.9. This enables analysis of a 15 mm × 15 mm slide area in only 3.3 minutes. We demonstrate that detection of only a few hundred photoelectrons within 100 μs is sufficient to distinguish a target event in a prototype system using ultraviolet LED excitation. Cytometric analysis of lanthanide labelled Giardia cysts achieved a signal-to-background ratio of two orders of magnitude. Results suggest that time-gated OSAM represents a new opportunity for high-throughput background-free biosensing applications.

A Novel Event-Based Incipient Slip Detection Using Dynamic Active-Pixel Vision Sensor (DAVIS)

PubMed Central

Rigi, Amin

2018-01-01

In this paper, a novel approach to detect incipient slip based on the contact area between a transparent silicone medium and different objects using a neuromorphic event-based vision sensor (DAVIS) is proposed. Event-based algorithms are developed to detect incipient slip, slip, stress distribution and object vibration. Thirty-seven experiments were performed on five objects with different sizes, shapes, materials and weights to compare precision and response time of the proposed approach. The proposed approach is validated by using a high speed constitutional camera (1000 FPS). The results indicate that the sensor can detect incipient slippage with an average of 44.1 ms latency in unstructured environment for various objects. It is worth mentioning that the experiments were conducted in an uncontrolled experimental environment, therefore adding high noise levels that affected results significantly. However, eleven of the experiments had a detection latency below 10 ms which shows the capability of this method. The results are very promising and show a high potential of the sensor being used for manipulation applications especially in dynamic environments. PMID:29364190

A novel spatter detection algorithm based on typical cellular neural network operations for laser beam welding processes

NASA Astrophysics Data System (ADS)

Nicolosi, L.; Abt, F.; Blug, A.; Heider, A.; Tetzlaff, R.; Höfler, H.

2012-01-01

Real-time monitoring of laser beam welding (LBW) has increasingly gained importance in several manufacturing processes ranging from automobile production to precision mechanics. In the latter, a novel algorithm for the real-time detection of spatters was implemented in a camera based on cellular neural networks. The latter can be connected to the optics of commercially available laser machines leading to real-time monitoring of LBW processes at rates up to 15 kHz. Such high monitoring rates allow the integration of other image evaluation tasks such as the detection of the full penetration hole for real-time control of process parameters.

Uav-Based 3d Urban Environment Monitoring

NASA Astrophysics Data System (ADS)

Boonpook, Wuttichai; Tan, Yumin; Liu, Huaqing; Zhao, Binbin; He, Lingfeng

2018-04-01

Unmanned Aerial Vehicle (UAV) based remote sensing can be used to make three-dimensions (3D) mapping with great flexibility, besides the ability to provide high resolution images. In this paper we propose a quick-change detection method on UAV images by combining altitude from Digital Surface Model (DSM) and texture analysis from images. Cases of UAV images with and without georeferencing are both considered. Research results show that the accuracy of change detection can be enhanced with georeferencing procedure, and the accuracy and precision of change detection on UAV images which are collected both vertically and obliquely but without georeferencing also have a good performance.

Development of high precision digital driver of acoustic-optical frequency shifter for ROG

NASA Astrophysics Data System (ADS)

Zhang, Rong; Kong, Mei; Xu, Yameng

2016-10-01

We develop a high precision digital driver of the acoustic-optical frequency shifter (AOFS) based on the parallel direct digital synthesizer (DDS) technology. We use an atomic clock as the phase-locked loop (PLL) reference clock, and the PLL is realized by a dual digital phase-locked loop. A DDS sampling clock up to 320 MHz with a frequency stability as low as 10-12 Hz is obtained. By constructing the RF signal measurement system, it is measured that the frequency output range of the AOFS-driver is 52-58 MHz, the center frequency of the band-pass filter is 55 MHz, the ripple in the band is less than 1 dB@3MHz, the single channel output power is up to 0.3 W, the frequency stability is 1 ppb (1 hour duration), and the frequency-shift precision is 0.1 Hz. The obtained frequency stability has two orders of improvement compared to that of the analog AOFS-drivers. For the designed binary frequency shift keying (2-FSK) and binary phase shift keying (2-PSK) modulation system, the demodulating frequency of the input TTL synchronous level signal is up to 10 kHz. The designed digital-bus coding/decoding system is compatible with many conventional digital bus protocols. It can interface with the ROG signal detecting software through the integrated drive electronics (IDE) and exchange data with the two DDS frequency-shift channels through the signal detecting software.

A portable, stable and precise laser differential refractometer

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

Gong, Xiangjun, E-mail: xjgong@cuhk.edu.hk, E-mail: chiwu@cuhk.edu.hk; Ngai, To; Wu, Chi, E-mail: xjgong@cuhk.edu.hk, E-mail: chiwu@cuhk.edu.hk

In this work, we present a portable laser differential refractometer with real-time detection and high precision based on the Snell's law and a 2f-2f optical design. The 2f-2f configuration solves a traditional position drifting problem of the laser beam and enhances the signal stability, where a small pinhole is illuminated by the laser light and imaged to the detector by lens placed in the middle between the detector and the pinhole. However, it also leads to a larger dimension of the instrument, limiting its applications and its sensitivity that is proportional to the optical path. Therefore, for a portable devicemore » on the basis of the 2f-2f design, a combination of a mirror and a lens was developed to minimize the optical path without affecting the 2f-2f design. Our simple and compact design reaches a resolution of 10{sup −6} refractive index units (RIU). Moreover, the dimension of such a modified differential refractometer is significantly reduced to be portable. Owing to its real-time detection speed and high precision, this newly developed refractometer is particularly attractive when it is used as an independent and ultra-sensitive detector in many research and industrial applications wherein there is a time-dependent concentration change, e.g., the concentration determination, quality control, and study of kinetic processes in solution, including adsorption, sedimentation, and dissolution, to name few but not limited.« less

A rapid method for the simultaneous determination of 25 anti-hypertensive compounds in dietary supplements using ultra-high-pressure liquid chromatography.

PubMed

Heo, Seok; Yoo, Geum Joo; Choi, Ji Yeon; Park, Hyoung Joon; Park, Sung-Kwan; Baek, Sun Young

2016-11-01

A novel, stable, simple and specific ultra-performance liquid chromatography method with ultraviolet detection (205 nm) for the simultaneous analysis of 25 anti-hypertensive substances was developed. The method was validated according to the International Conference of Harmonisation guidelines with respect to linearity, accuracy, precision, limit of detection (LOD), limit of quantitation (LOQ) and stability. From the ultra-performance liquid chromatography results, we identified the LOD and LOQ of solid samples to be 0.20-1.00 and 0.60-3.00 μg ml -1 , respectively, while those of liquid samples were 0.30-1.20 and 0.90-3.60 μg ml -1 , respectively. The linearity exceeded 0.9999, and the intra- and inter-day precisions were 0.15-6.48% and 0.28-8.67%, respectively. The intra- and inter-day accuracies were 82.25-111.42% and 80.70-115.64%, respectively, and the stability was lower than 12.9% (relative standard deviation). This method was applied to the monitoring of 97 commercially available dietary supplements obtained in Korea, such as pills, soft capsules, hard capsules, liquids, powders and tablets. The proposed method is accurate, precise and of high quality, and can be used for the routine, reproducible analysis and control of 25 anti-hypertensive substances in various dietary supplements. The work presented herein may help to prevent incidents related to food adulteration and restrict the illegal food market.

A Search for Transiting Neptune-Mass Extrasolar Planets in High-Precision Photometry of Solar-Type Stars

NASA Technical Reports Server (NTRS)

Henry, Stephen M.; Gillman, Amelie r.; Henry, Gregory W.

2005-01-01

Tennessee State University operates several automatic photometric telescopes (APTs) at Fairborn Observatory in southern Arizona. Four 0.8 m APTs have been dedicated to measuring subtle luminosity variations that accompany magnetic cycles in solar-type stars. Over 1000 program and comparison stars have been observed every clear night in this program for up to 12 years with a precision of approximately 0.0015 mag for a single observation. We have developed a transit-search algorithm, based on fitting a computed transit template for each trial period, and have used it to search our photometric database for transits of unknown companions. Extensive simulations with the APT data have shown that we can reliably recover transits with periods under 10 days as long as the transits have a depth of at least 0.0024 mag, or about 1.6 times the scatter in the photometric observations. Thus, due to our high photometric precision, we are sensitive to transits of possible short-period Neptune-mass planets that likely would have escaped detection by current radial velocity techniques. Our search of the APT data sets for 1087 program and comparison stars revealed no new transiting planets. However, the detection of several unknown grazing eclipsing binaries from among our comparison stars, with eclipse depths of only a few millimags, illustrates the success of our technique. We have used this negative result to place limits on the frequency of Neptune-mass planets in close orbits around solar-type stars in the Sun's vicinity.

Enhancing the detection of barcoded reads in high throughput DNA sequencing data by controlling the false discovery rate.

PubMed

Buschmann, Tilo; Zhang, Rong; Brash, Douglas E; Bystrykh, Leonid V

2014-08-07

DNA barcodes are short unique sequences used to label DNA or RNA-derived samples in multiplexed deep sequencing experiments. During the demultiplexing step, barcodes must be detected and their position identified. In some cases (e.g., with PacBio SMRT), the position of the barcode and DNA context is not well defined. Many reads start inside the genomic insert so that adjacent primers might be missed. The matter is further complicated by coincidental similarities between barcode sequences and reference DNA. Therefore, a robust strategy is required in order to detect barcoded reads and avoid a large number of false positives or negatives.For mass inference problems such as this one, false discovery rate (FDR) methods are powerful and balanced solutions. Since existing FDR methods cannot be applied to this particular problem, we present an adapted FDR method that is suitable for the detection of barcoded reads as well as suggest possible improvements. In our analysis, barcode sequences showed high rates of coincidental similarities with the Mus musculus reference DNA. This problem became more acute when the length of the barcode sequence decreased and the number of barcodes in the set increased. The method presented in this paper controls the tail area-based false discovery rate to distinguish between barcoded and unbarcoded reads. This method helps to establish the highest acceptable minimal distance between reads and barcode sequences. In a proof of concept experiment we correctly detected barcodes in 83% of the reads with a precision of 89%. Sensitivity improved to 99% at 99% precision when the adjacent primer sequence was incorporated in the analysis. The analysis was further improved using a paired end strategy. Following an analysis of the data for sequence variants induced in the Atp1a1 gene of C57BL/6 murine melanocytes by ultraviolet light and conferring resistance to ouabain, we found no evidence of cross-contamination of DNA material between samples. Our method offers a proper quantitative treatment of the problem of detecting barcoded reads in a noisy sequencing environment. It is based on the false discovery rate statistics that allows a proper trade-off between sensitivity and precision to be chosen.

Mobile Measurement of Methane and Ethane for the Detection and Attribution of Natural Gas Pipeline Leaks Using Off-Axis Integrated Output Spectroscopy

NASA Astrophysics Data System (ADS)

Leen, J. B.; Spillane, S.; Gardner, A.; Hansen, P. C.; Gupta, M.; Baer, D. S.

2015-12-01

Natural gas leaks pose a risk to public safety both because of potential explosions as well as from the greenhouse gas potential of fugitive methane. The rapid and cost effective detection of leaks in natural gas distribution is critical to providing a system that is safe for the public and the environment. Detection of methane from a mobile platform (vehicles, aircraft, etc.) is an accepted method of identifying leaks. A robust approach to differentiating pipeline gas (thermogenic) from other biogenic sources is the detection of ethane along with methane. Ethane is present in nearly all thermogenic gas but not in biogenic sources and its presence can be used to positively identify a gas sample. We present a mobile system for the simultaneous measurement of methane and ethane that is capable of detecting pipeline leaks and differentiating pipeline gas from other biogenic sources such as landfills, swamps, sewers, and enteric fermentation. The mobile system consists of a high precision GPS, sonic anemometer, and methane/ethane analyzer based on off-axis integrated cavity output spectroscopy (OA-ICOS). In order to minimize the system cost and facilitate the wide use of mobile leak detection, the analyzer operates in the near-infrared portion of the spectrum where lasers and optics are significantly less costly than in the mid-infrared. The analyzer is capable of detecting methane with a precision of <2 ppb (1σ in 1 sec) and detecting ethane with a precision of <30 ppb (1σ in 1 sec). Additionally, measurement rates of 5 Hz allow for detection of leaks at speeds up to 50 mph. The sonic anemometer, GPS and analyzer inlet are mounted to a generic roof rack for attachment to available fleet vehicles. The system can detect leaks having a downwind concentration of as little as 10 ppb of methane above ambient, while leaks 500 ppb above ambient can be identified as thermogenic with greater than 99% certainty (for gas with 6% ethane). Finally, analysis of wind data provides an estimate of leak direction and distance. The system presented provides a robust, cost effective solution to natural gas leak detection and attribution to maximize safety and minimize greenhouse gas impacts of distribution systems.

Multisource oil spill detection

NASA Astrophysics Data System (ADS)

Salberg, Arnt B.; Larsen, Siri O.; Zortea, Maciel

2013-10-01

In this paper we discuss how multisource data (wind, ocean-current, optical, bathymetric, automatic identification systems (AIS)) may be used to improve oil spill detection in SAR images, with emphasis on the use of automatic oil spill detection algorithms. We focus particularly on AIS, optical, and bathymetric data. For the AIS data we propose an algorithm for integrating AIS ship tracks into automatic oil spill detection in order to improve the confidence estimate of a potential oil spill. We demonstrate the use of ancillary data on a set of SAR images. Regarding the use of optical data, we did not observe a clear correspondence between high chlorophyll values (estimated from products derived from optical data) and observed slicks in the SAR image. Bathymetric data was shown to be a good data source for removing false detections caused by e.g. sand banks on low tide. For the AIS data we observed that a polluter could be identified for some dark slicks, however, a precise oil drift model is needed in order to identify the polluter with high certainty.

Detecting the Water-soluble Chloride Distribution of Cement Paste in a High-precision Way.

PubMed

Chang, Honglei; Mu, Song

2017-11-21

To improve the accuracy of the chloride distribution along the depth of cement paste under cyclic wet-dry conditions, a new method is proposed to obtain a high-precision chloride profile. Firstly, paste specimens are molded, cured, and exposed to cyclic wet-dry conditions. Then, powder samples at different specimen depths are grinded when the exposure age is reached. Finally, the water-soluble chloride content is detected using a silver nitrate titration method, and chloride profiles are plotted. The key to improving the accuracy of the chloride distribution along the depth is to exclude the error in the powderization, which is the most critical step for testing the distribution of chloride. Based on the above concept, the grinding method in this protocol can be used to grind powder samples automatically layer by layer from the surface inward, and it should be noted that a very thin grinding thickness (less than 0.5 mm) with a minimum error less than 0.04 mm can be obtained. The chloride profile obtained by this method better reflects the chloride distribution in specimens, which helps researchers to capture the distribution features that are often overlooked. Furthermore, this method can be applied to studies in the field of cement-based materials, which require high chloride distribution accuracy.

Comparative Analysis of Automatic Exudate Detection between Machine Learning and Traditional Approaches

NASA Astrophysics Data System (ADS)

Sopharak, Akara; Uyyanonvara, Bunyarit; Barman, Sarah; Williamson, Thomas

To prevent blindness from diabetic retinopathy, periodic screening and early diagnosis are neccessary. Due to lack of expert ophthalmologists in rural area, automated early exudate (one of visible sign of diabetic retinopathy) detection could help to reduce the number of blindness in diabetic patients. Traditional automatic exudate detection methods are based on specific parameter configuration, while the machine learning approaches which seems more flexible may be computationally high cost. A comparative analysis of traditional and machine learning of exudates detection, namely, mathematical morphology, fuzzy c-means clustering, naive Bayesian classifier, Support Vector Machine and Nearest Neighbor classifier are presented. Detected exudates are validated with expert ophthalmologists' hand-drawn ground-truths. The sensitivity, specificity, precision, accuracy and time complexity of each method are also compared.

The prospects of pulsar timing with new-generation radio telescopes and the Square Kilometre Array

NASA Astrophysics Data System (ADS)

Stappers, B. W.; Keane, E. F.; Kramer, M.; Possenti, A.; Stairs, I. H.

2018-05-01

Pulsars are highly magnetized and rapidly rotating neutron stars. As they spin, the lighthouse-like beam of radio emission from their magnetic poles sweeps across the Earth with a regularity approaching that of the most precise clocks known. This precision combined with the extreme environments in which they are found, often in compact orbits with other neutron stars and white dwarfs, makes them excellent tools for studying gravity. Present and near-future pulsar surveys, especially those using the new generation of telescopes, will find more extreme binary systems and pulsars that are more precise `clocks'. These telescopes will also greatly improve the precision to which we can measure the arrival times of the pulses. The Square Kilometre Array will revolutionize pulsar searches and timing precision. The increased number of sources will reveal rare sources, including possibly a pulsar-black hole binary, which can provide the most stringent tests of strong-field gravity. The improved timing precision will reveal new phenomena and also allow us to make a detection of gravitational waves in the nanohertz frequency regime. It is here where we expect to see the signature of the binary black holes that are formed as galaxies merge throughout cosmological history. This article is part of a discussion meeting issue `The promises of gravitational-wave astronomy'.

High-precision branching-ratio measurement for the superallowed β+ emitter 74Rb

NASA Astrophysics Data System (ADS)

Dunlop, R.; Ball, G. C.; Leslie, J. R.; Svensson, C. E.; Towner, I. S.; Andreoiu, C.; Chagnon-Lessard, S.; Chester, A.; Cross, D. S.; Finlay, P.; Garnsworthy, A. B.; Garrett, P. E.; Glister, J.; Hackman, G.; Hadinia, B.; Leach, K. G.; Rand, E. T.; Starosta, K.; Tardiff, E. R.; Triambak, S.; Williams, S. J.; Wong, J.; Yates, S. W.; Zganjar, E. F.

2013-10-01

A high-precision branching-ratio measurement for the superallowed β+ decay of 74Rb was performed at the TRIUMF Isotope Separator and Accelerator (ISAC) radioactive ion-beam facility. The scintillating electron-positron tagging array (SCEPTAR), composed of 10 thin plastic scintillators, was used to detect the emitted β particles; the 8π spectrometer, an array of 20 Compton-suppressed HPGe detectors, was used for detecting γ rays that were emitted following Gamow-Teller and nonanalog Fermi β+ decays of 74Rb; and the Pentagonal Array of Conversion Electron Spectrometers (PACES), an array of 5 Si(Li) detectors, was employed for measuring β-delayed conversion electrons. Twenty-three excited states were identified in 74Kr following 8.241(4)×108 detected 74Rb β decays. A total of 58 γ-ray and electron transitions were placed in the decay scheme, allowing the superallowed branching ratio to be determined as B0=99.545(31)%. Combined with previous half-life and Q-value measurements, the superallowed branching ratio measured in this work leads to a superallowed ft value of 3082.8(65) s. Comparisons between this superallowed ft value and the world-average-corrected Ft¯ value, as well as the nonanalog Fermi branching ratios determined in this work, provide guidance for theoretical models of the isospin-symmetry-breaking corrections in this mass region.

Robust Fault Detection and Isolation for Stochastic Systems

NASA Technical Reports Server (NTRS)

George, Jemin; Gregory, Irene M.

2010-01-01

This paper outlines the formulation of a robust fault detection and isolation scheme that can precisely detect and isolate simultaneous actuator and sensor faults for uncertain linear stochastic systems. The given robust fault detection scheme based on the discontinuous robust observer approach would be able to distinguish between model uncertainties and actuator failures and therefore eliminate the problem of false alarms. Since the proposed approach involves precise reconstruction of sensor faults, it can also be used for sensor fault identification and the reconstruction of true outputs from faulty sensor outputs. Simulation results presented here validate the effectiveness of the robust fault detection and isolation system.

Advancing the speed, sensitivity and accuracy of biomolecular detection using multi-length-scale engineering

PubMed Central

Kelley, Shana O.; Mirkin, Chad A.; Walt, David R.; Ismagilov, Rustem F.; Toner, Mehmet; Sargent, Edward H.

2015-01-01

Rapid progress in identifying disease biomarkers has increased the importance of creating high-performance detection technologies. Over the last decade, the design of many detection platforms has focused on either the nano or micro length scale. Here, we review recent strategies that combine nano- and microscale materials and devices to produce large improvements in detection sensitivity, speed and accuracy, allowing previously undetectable biomarkers to be identified in clinical samples. Microsensors that incorporate nanoscale features can now rapidly detect disease-related nucleic acids expressed in patient samples. New microdevices that separate large clinical samples into nanocompartments allow precise quantitation of analytes, and microfluidic systems that utilize nanoscale binding events can detect rare cancer cells in the bloodstream more accurately than before. These advances will lead to faster and more reliable clinical diagnostic devices. PMID:25466541

Advancing the speed, sensitivity and accuracy of biomolecular detection using multi-length-scale engineering

NASA Astrophysics Data System (ADS)

Kelley, Shana O.; Mirkin, Chad A.; Walt, David R.; Ismagilov, Rustem F.; Toner, Mehmet; Sargent, Edward H.

2014-12-01

Rapid progress in identifying disease biomarkers has increased the importance of creating high-performance detection technologies. Over the last decade, the design of many detection platforms has focused on either the nano or micro length scale. Here, we review recent strategies that combine nano- and microscale materials and devices to produce large improvements in detection sensitivity, speed and accuracy, allowing previously undetectable biomarkers to be identified in clinical samples. Microsensors that incorporate nanoscale features can now rapidly detect disease-related nucleic acids expressed in patient samples. New microdevices that separate large clinical samples into nanocompartments allow precise quantitation of analytes, and microfluidic systems that utilize nanoscale binding events can detect rare cancer cells in the bloodstream more accurately than before. These advances will lead to faster and more reliable clinical diagnostic devices.

Analysis of the dynamic behavior of structures using the high-rate GNSS-PPP method combined with a wavelet-neural model: Numerical simulation and experimental tests

NASA Astrophysics Data System (ADS)

Kaloop, Mosbeh R.; Yigit, Cemal O.; Hu, Jong W.

2018-03-01

Recently, the high rate global navigation satellite system-precise point positioning (GNSS-PPP) technique has been used to detect the dynamic behavior of structures. This study aimed to increase the accuracy of the extraction oscillation properties of structural movements based on the high-rate (10 Hz) GNSS-PPP monitoring technique. A developmental model based on the combination of wavelet package transformation (WPT) de-noising and neural network prediction (NN) was proposed to improve the dynamic behavior of structures for GNSS-PPP method. A complicated numerical simulation involving highly noisy data and 13 experimental cases with different loads were utilized to confirm the efficiency of the proposed model design and the monitoring technique in detecting the dynamic behavior of structures. The results revealed that, when combined with the proposed model, GNSS-PPP method can be used to accurately detect the dynamic behavior of engineering structures as an alternative to relative GNSS method.

Detecting and Characterizing Semantic Inconsistencies in Ported Code

NASA Technical Reports Server (NTRS)

Ray, Baishakhi; Kim, Miryung; Person, Suzette J.; Rungta, Neha

2013-01-01

Adding similar features and bug fixes often requires porting program patches from reference implementations and adapting them to target implementations. Porting errors may result from faulty adaptations or inconsistent updates. This paper investigates (I) the types of porting errors found in practice, and (2) how to detect and characterize potential porting errors. Analyzing version histories, we define five categories of porting errors, including incorrect control- and data-flow, code redundancy, inconsistent identifier renamings, etc. Leveraging this categorization, we design a static control- and data-dependence analysis technique, SPA, to detect and characterize porting inconsistencies. Our evaluation on code from four open-source projects shows thai SPA can dell-oct porting inconsistencies with 65% to 73% precision and 90% recall, and identify inconsistency types with 58% to 63% precision and 92% to 100% recall. In a comparison with two existing error detection tools, SPA improves precision by 14 to 17 percentage points

Receptor-based screening assays for the detection of antibiotics residues - A review.

PubMed

Ahmed, Saeed; Ning, Jianan; Cheng, Guyue; Ahmad, Ijaz; Li, Jun; Mingyue, Liu; Qu, Wei; Iqbal, Mujahid; Shabbir, M A B; Yuan, Zonghui

2017-05-01

Consumer and regulatory agencies have a high concern to antibiotic residues in food producing animals, so appropriate screening assays of fast, sensitive, low cost, and easy sample preparation for the identification of these residues are essential for the food-safety insurance. Great efforts in the development of a high-throughput antibiotic screening assay have been made in recent years. Concerning the screening of antibiotic residue, this review elaborate an overview on the availability, advancement and applicability of antibiotic receptor based screening assays for the safety assessment of antibiotics usage (i.e. radio receptor assay, enzyme labeling assays, colloidal gold receptor assay, enzyme colorimetry assay and biosensor assay). This manuscript also tries to shed a light on the selection, preparation and future perspective of receptor protein for antibiotic residue detection. These assays have been introduced for the screening of numerous food samples. Receptor based screening technology for antibiotic detection has high accuracy. It has been concluded that at the same time, it can detect a class of drugs for certain receptor, and realize the multi-residue detection. These assays offer fast, easy and precise detection of antibiotics. Copyright © 2017 Elsevier B.V. All rights reserved.

Normal and polar-organic-phase high-performance liquid chromatographic enantioresolution of omeprazole, rabeprazole, lansoprazole and pantoprazole using monochloro-methylated cellulose-based chiral stationary phase and determination of dexrabeprazole.

PubMed

Dixit, Shuchi; Dubey, Rituraj; Bhushan, Ravi

2014-01-01

Enantioresolution of four anti-ulcer drugs (chiral sulfoxides), namely, omeprazole, rabeprazole, lansoprazole and pantoprazole, was carried out by high-performance liquid chromatography using a polysaccharide-based chiral stationary phase consisting of monochloromethylated cellulose (Lux cellulose-2) under normal and polar-organic-phase conditions with ultraviolet detection at 285 nm. The method was validated for linearity, accuracy, precision, robustness and limit of detection. The optimized enantioresolution method was compared for both the elution modes. The optimized method was further utilized to check the enantiomeric purity of dexrabeprazole. Copyright © 2013 John Wiley & Sons, Ltd.

Multinode acoustic focusing for parallel flow cytometry

PubMed Central

Piyasena, Menake E.; Suthanthiraraj, Pearlson P. Austin; Applegate, Robert W.; Goumas, Andrew M.; Woods, Travis A.; López, Gabriel P.; Graves, Steven W.

2012-01-01

Flow cytometry can simultaneously measure and analyze multiple properties of single cells or particles with high sensitivity and precision. Yet, conventional flow cytometers have fundamental limitations with regards to analyzing particles larger than about 70 microns, analyzing at flow rates greater than a few hundred microliters per minute, and providing analysis rates greater than 50,000 per second. To overcome these limits, we have developed multi-node acoustic focusing flow cells that can position particles (as small as a red blood cell and as large as 107 microns in diameter) into as many as 37 parallel flow streams. We demonstrate the potential of such flow cells for the development of high throughput, parallel flow cytometers by precision focusing of flow cytometry alignment microspheres, red blood cells, and the analysis of CD4+ cellular immunophenotyping assay. This approach will have significant impact towards the creation of high throughput flow cytometers for rare cell detection applications (e.g. circulating tumor cells), applications requiring large particle analysis, and high volume flow cytometry. PMID:22239072

Rapid Development and Validation of Improved Reversed-Phase High-performance Liquid Chromatography Method for the Quantification of Mangiferin, a Polyphenol Xanthone Glycoside in Mangifera indica

PubMed Central

Naveen, P.; Lingaraju, H. B.; Prasad, K. Shyam

2017-01-01

Mangiferin, a polyphenolic xanthone glycoside from Mangifera indica, is used as traditional medicine for the treatment of numerous diseases. The present study was aimed to develop and validate a reversed-phase high-performance liquid chromatography (RP-HPLC) method for the quantification of mangiferin from the bark extract of M. indica. RP-HPLC analysis was performed by isocratic elution with a low-pressure gradient using 0.1% formic acid: acetonitrile (87:13) as a mobile phase with a flow rate of 1.5 ml/min. The separation was done at 26°C using a Kinetex XB-C18 column as stationary phase and the detection wavelength at 256 nm. The proposed method was validated for linearity, precision, accuracy, limit of detection, limit of quantification, and robustness by the International Conference on Harmonisation guidelines. In linearity, the excellent correlation coefficient more than 0.999 indicated good fitting of the curve and also good linearity. The intra- and inter-day precision showed < 1% of relative standard deviation of peak area indicated high reliability and reproducibility of the method. The recovery values at three different levels (50%, 100%, and 150%) of spiked samples were found to be 100.47, 100.89, and 100.99, respectively, and low standard deviation value < 1% shows high accuracy of the method. In robustness, the results remain unaffected by small variation in the analytical parameters, which shows the robustness of the method. Liquid chromatography–mass spectrometry analysis confirmed the presence of mangiferin with M/Z value of 421. The assay developed by HPLC method is a simple, rapid, and reliable for the determination of mangiferin from M. indica. SUMMARY The present study was intended to develop and validate an RP-HPLC method for the quantification of mangiferin from the bark extract of M. indica. The developed method was validated for linearity, precision, accuracy, limit of detection, limit of quantification and robustness by International Conference on Harmonization guidelines. This study proved that the developed assay by HPLC method is a simple, rapid and reliable for the quantification of the mangiferin from M. indica. Abbreviations Used: M. indica: Mangifera indica, RP-HPLC: Reversed-phase high-performance liquid chromatography, M/Z: Mass to charge ratio, ICH: International conference on harmonization, % RSD: Percentage of relative standard deviation, ppm: Parts per million, LOD: Limit of detection, LOQ: Limit of quantification. PMID:28539748

Rapid Development and Validation of Improved Reversed-Phase High-performance Liquid Chromatography Method for the Quantification of Mangiferin, a Polyphenol Xanthone Glycoside in Mangifera indica.

PubMed

Naveen, P; Lingaraju, H B; Prasad, K Shyam

2017-01-01

Mangiferin, a polyphenolic xanthone glycoside from Mangifera indica , is used as traditional medicine for the treatment of numerous diseases. The present study was aimed to develop and validate a reversed-phase high-performance liquid chromatography (RP-HPLC) method for the quantification of mangiferin from the bark extract of M. indica . RP-HPLC analysis was performed by isocratic elution with a low-pressure gradient using 0.1% formic acid: acetonitrile (87:13) as a mobile phase with a flow rate of 1.5 ml/min. The separation was done at 26°C using a Kinetex XB-C18 column as stationary phase and the detection wavelength at 256 nm. The proposed method was validated for linearity, precision, accuracy, limit of detection, limit of quantification, and robustness by the International Conference on Harmonisation guidelines. In linearity, the excellent correlation coefficient more than 0.999 indicated good fitting of the curve and also good linearity. The intra- and inter-day precision showed < 1% of relative standard deviation of peak area indicated high reliability and reproducibility of the method. The recovery values at three different levels (50%, 100%, and 150%) of spiked samples were found to be 100.47, 100.89, and 100.99, respectively, and low standard deviation value < 1% shows high accuracy of the method. In robustness, the results remain unaffected by small variation in the analytical parameters, which shows the robustness of the method. Liquid chromatography-mass spectrometry analysis confirmed the presence of mangiferin with M/Z value of 421. The assay developed by HPLC method is a simple, rapid, and reliable for the determination of mangiferin from M. indica . The present study was intended to develop and validate an RP-HPLC method for the quantification of mangiferin from the bark extract of M. indica . The developed method was validated for linearity, precision, accuracy, limit of detection, limit of quantification and robustness by International Conference on Harmonization guidelines. This study proved that the developed assay by HPLC method is a simple, rapid and reliable for the quantification of the mangiferin from M. indica . Abbreviations Used: M. indica : Mangifera indica , RP-HPLC: Reversed-phase high-performance liquid chromatography, M/Z: Mass to charge ratio, ICH: International conference on harmonization, % RSD: Percentage of relative standard deviation, ppm: Parts per million, LOD: Limit of detection, LOQ: Limit of quantification.

Determination of illegal adulteration of dietary supplements with synthetic hair-growth compounds by UPLC and LC-Q-TOF/MS.

PubMed

Lee, Ji Hyun; Kang, Gihaeng; Park, Han Na; Kim, Jihee; Kim, Nam Sook; Park, Seongsoo; Park, Sung-Kwan; Baek, Sun Young; Kang, Hoil

2018-02-01

In this study, we developed a UPLC-PDA and LC-Q-TOF/MS method to identify and measure the following prohibited substances that may be found in dietary supplements:triaminodil, minoxidil, bimatoprost, alimemazine, diphenylcyclopropenone, α-tradiol, finasteride, methyltestosterone, spironolatone, flutamide, cyproterone, dutasteride, and testosterone 17-propionate.The method was validated according to International Conference on Harmonization guidelines in terms of specificity, linearity, accuracy, precision, LOD, LOQ, recovery, and stability. The method was completely validated showing satisfactory data for all method validation parameters. The linearity was good (R 2  > 0.999) with intra- and inter-day precision values of 0.2-3.4% and 0.3-2.9%, respectively. Moreover, the intra- and inter-day accuracies were 87-102% and 86-103%, respectively, and the precision was better than 9.4% (relative standard deviation).Hence, the proposed method is precise and has high quality,and can be utilised to comprehensively and continually monitor illegal drug adulteration in various forms of dietary supplements. Furthermore, to evaluate the applicability of the proposed method, we analysed 13 hair-growth compounds in 78 samples including food and dietary supplements. Minoxidil and triaminodil were detected in capsules at concentrations of 4.69 mg/g and 6.54 mg/g. In addition, finasteride was detected in a tablet at 13.45 mg/g. In addition, the major characteristic fragment ions were confirmed once again using LC-Q-TOF/MS for higher accuracy.

HIGH-PRECISION BIOLOGICAL EVENT EXTRACTION: EFFECTS OF SYSTEM AND OF DATA

PubMed Central

Cohen, K. Bretonnel; Verspoor, Karin; Johnson, Helen L.; Roeder, Chris; Ogren, Philip V.; Baumgartner, William A.; White, Elizabeth; Tipney, Hannah; Hunter, Lawrence

2013-01-01

We approached the problems of event detection, argument identification, and negation and speculation detection in the BioNLP’09 information extraction challenge through concept recognition and analysis. Our methodology involved using the OpenDMAP semantic parser with manually written rules. The original OpenDMAP system was updated for this challenge with a broad ontology defined for the events of interest, new linguistic patterns for those events, and specialized coordination handling. We achieved state-of-the-art precision for two of the three tasks, scoring the highest of 24 teams at precision of 71.81 on Task 1 and the highest of 6 teams at precision of 70.97 on Task 2. We provide a detailed analysis of the training data and show that a number of trigger words were ambiguous as to event type, even when their arguments are constrained by semantic class. The data is also shown to have a number of missing annotations. Analysis of a sampling of the comparatively small number of false positives returned by our system shows that major causes of this type of error were failing to recognize second themes in two-theme events, failing to recognize events when they were the arguments to other events, failure to recognize nontheme arguments, and sentence segmentation errors. We show that specifically handling coordination had a small but important impact on the overall performance of the system. The OpenDMAP system and the rule set are available at http://bionlp.sourceforge.net. PMID:25937701

MultiGeMS: detection of SNVs from multiple samples using model selection on high-throughput sequencing data.

PubMed

Murillo, Gabriel H; You, Na; Su, Xiaoquan; Cui, Wei; Reilly, Muredach P; Li, Mingyao; Ning, Kang; Cui, Xinping

2016-05-15

Single nucleotide variant (SNV) detection procedures are being utilized as never before to analyze the recent abundance of high-throughput DNA sequencing data, both on single and multiple sample datasets. Building on previously published work with the single sample SNV caller genotype model selection (GeMS), a multiple sample version of GeMS (MultiGeMS) is introduced. Unlike other popular multiple sample SNV callers, the MultiGeMS statistical model accounts for enzymatic substitution sequencing errors. It also addresses the multiple testing problem endemic to multiple sample SNV calling and utilizes high performance computing (HPC) techniques. A simulation study demonstrates that MultiGeMS ranks highest in precision among a selection of popular multiple sample SNV callers, while showing exceptional recall in calling common SNVs. Further, both simulation studies and real data analyses indicate that MultiGeMS is robust to low-quality data. We also demonstrate that accounting for enzymatic substitution sequencing errors not only improves SNV call precision at low mapping quality regions, but also improves recall at reference allele-dominated sites with high mapping quality. The MultiGeMS package can be downloaded from https://github.com/cui-lab/multigems xinping.cui@ucr.edu Supplementary data are available at Bioinformatics online. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

The research and development of the non-contact detection of the tubing internal thread with a line structured light

NASA Astrophysics Data System (ADS)

Hu, Yuanyuan; Xu, Yingying; Hao, Qun; Hu, Yao

2013-12-01

The tubing internal thread plays an irreplaceable role in the petroleum equipment. The unqualified tubing can directly lead to leakage, slippage and bring huge losses for oil industry. For the purpose of improving efficiency and precision of tubing internal thread detection, we develop a new non-contact tubing internal thread measurement system based on the laser triangulation principle. Firstly, considering that the tubing thread had a small diameter and relatively smooth surface, we built a set of optical system with a line structured light to irradiate the internal thread surface and obtain an image which contains the internal thread profile information through photoelectric sensor. Secondly, image processing techniques were used to do the edge detection of the internal thread from the obtained image. One key method was the sub-pixel technique which greatly improved the detection accuracy under the same hardware conditions. Finally, we restored the real internal thread contour information on the basis of laser triangulation method and calculated tubing thread parameters such as the pitch, taper and tooth type angle. In this system, the profile of several thread teeth can be obtained at the same time. Compared with other existing scanning methods using point light and stepper motor, this system greatly improves the detection efficiency. Experiment results indicate that this system can achieve the high precision and non-contact measurement of the tubing internal thread.

Myostatin inhibitors in sports drug testing: Detection of myostatin-neutralizing antibodies in plasma/serum by affinity purification and Western blotting.

PubMed

Walpurgis, Katja; Thomas, Andreas; Schänzer, Wilhelm; Thevis, Mario

2016-02-01

Myostatin is a key regulator of skeletal muscle growth and inhibition of its signaling pathway results in an increased muscle mass and function. The aim of this study was to develop a qualitative detection assay for myostatin-neutralizing antibodies for doping control purposes by using immunological approaches. To detect different types of myostatin-neutralizing antibodies irrespective of their amino acid sequence, an immunological assay specific for antibodies directed against myostatin and having a human Fc domain was established. Affinity purification and Western blotting strategies were combined to allow extracting and identifying relevant analytes from 200 μL of plasma/serum in a non-targeted approach. The assay was characterized regarding specificity, linearity, precision, robustness, and recovery. The assay was found to be highly specific, robust, and linear from 0.1 to 1 μg/mL. The precision was successfully specified at three different concentrations and the recovery of the affinity purification was 58%. Within this study, an immunological detection assay for myostatin-neutralizing antibodies present in plasma/serum specimens was developed and successfully characterized. The presented approach can easily be modified to include other therapeutic antibodies and serves as proof-of-concept for the detection of antibody-based myostatin inhibitors in doping control samples. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Supervised Learning for Detection of Duplicates in Genomic Sequence Databases.

PubMed

Chen, Qingyu; Zobel, Justin; Zhang, Xiuzhen; Verspoor, Karin

2016-01-01

First identified as an issue in 1996, duplication in biological databases introduces redundancy and even leads to inconsistency when contradictory information appears. The amount of data makes purely manual de-duplication impractical, and existing automatic systems cannot detect duplicates as precisely as can experts. Supervised learning has the potential to address such problems by building automatic systems that learn from expert curation to detect duplicates precisely and efficiently. While machine learning is a mature approach in other duplicate detection contexts, it has seen only preliminary application in genomic sequence databases. We developed and evaluated a supervised duplicate detection method based on an expert curated dataset of duplicates, containing over one million pairs across five organisms derived from genomic sequence databases. We selected 22 features to represent distinct attributes of the database records, and developed a binary model and a multi-class model. Both models achieve promising performance; under cross-validation, the binary model had over 90% accuracy in each of the five organisms, while the multi-class model maintains high accuracy and is more robust in generalisation. We performed an ablation study to quantify the impact of different sequence record features, finding that features derived from meta-data, sequence identity, and alignment quality impact performance most strongly. The study demonstrates machine learning can be an effective additional tool for de-duplication of genomic sequence databases. All Data are available as described in the supplementary material.

Wireless inertial measurement of head kinematics in freely-moving rats

PubMed Central

Pasquet, Matthieu O.; Tihy, Matthieu; Gourgeon, Aurélie; Pompili, Marco N.; Godsil, Bill P.; Léna, Clément; Dugué, Guillaume P.

2016-01-01

While miniature inertial sensors offer a promising means for precisely detecting, quantifying and classifying animal behaviors, versatile inertial sensing devices adapted for small, freely-moving laboratory animals are still lacking. We developed a standalone and cost-effective platform for performing high-rate wireless inertial measurements of head movements in rats. Our system is designed to enable real-time bidirectional communication between the headborne inertial sensing device and third party systems, which can be used for precise data timestamping and low-latency motion-triggered applications. We illustrate the usefulness of our system in diverse experimental situations. We show that our system can be used for precisely quantifying motor responses evoked by external stimuli, for characterizing head kinematics during normal behavior and for monitoring head posture under normal and pathological conditions obtained using unilateral vestibular lesions. We also introduce and validate a novel method for automatically quantifying behavioral freezing during Pavlovian fear conditioning experiments, which offers superior performance in terms of precision, temporal resolution and efficiency. Thus, this system precisely acquires movement information in freely-moving animals, and can enable objective and quantitative behavioral scoring methods in a wide variety of experimental situations. PMID:27767085

CORRECTING FOR INTERSTELLAR SCATTERING DELAY IN HIGH-PRECISION PULSAR TIMING: SIMULATION RESULTS

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

Palliyaguru, Nipuni; McLaughlin, Maura; Stinebring, Daniel

2015-12-20

Light travel time changes due to gravitational waves (GWs) may be detected within the next decade through precision timing of millisecond pulsars. Removal of frequency-dependent interstellar medium (ISM) delays due to dispersion and scattering is a key issue in the detection process. Current timing algorithms routinely correct pulse times of arrival (TOAs) for time-variable delays due to cold plasma dispersion. However, none of the major pulsar timing groups correct for delays due to scattering from multi-path propagation in the ISM. Scattering introduces a frequency-dependent phase change in the signal that results in pulse broadening and arrival time delays. Any methodmore » to correct the TOA for interstellar propagation effects must be based on multi-frequency measurements that can effectively separate dispersion and scattering delay terms from frequency-independent perturbations such as those due to a GW. Cyclic spectroscopy, first described in an astronomical context by Demorest (2011), is a potentially powerful tool to assist in this multi-frequency decomposition. As a step toward a more comprehensive ISM propagation delay correction, we demonstrate through a simulation that we can accurately recover impulse response functions (IRFs), such as those that would be introduced by multi-path scattering, with a realistic signal-to-noise ratio (S/N). We demonstrate that timing precision is improved when scatter-corrected TOAs are used, under the assumptions of a high S/N and highly scattered signal. We also show that the effect of pulse-to-pulse “jitter” is not a serious problem for IRF reconstruction, at least for jitter levels comparable to those observed in several bright pulsars.« less

Solid phase extraction with high polarity Carb/PSA as composite fillers prior to UPLC-MS/MS to determine six bisphenols and alkylphenols in trace level hotpot seasoning.

PubMed

Dong, Hao; Zeng, Xiaofang; Bai, Weidong

2018-08-30

The present study reports an ultra high-performance liquid chromatography tandem mass spectrometry method for the simultaneous determination of six bisphenols (bisphenol A, bisphenol B and bisphenol F) and alkylphenols (4-nonylphenol, 4-n-nonylphenol and octylphenol) in hotpot seasoning. Samples were dispersed in n-hexane after addition of internal standards bisphenol A-d 4 and 4-n-nonylphenol-d 4 . Sample solutions were then centrifuged, and the supernatants purified using solid phase extraction with high polarity Carb/PSA composite fillers. Six target analytes were separated on a Waters ACQUITY BEH C18 column by gradient elution with methanol and 0.05% ammonium hydroxide in water as the mobile phase, and determined under multiple reactions monitoring mode. The limits of detection and quantitation, matrix effect, recovery and precision of the method were investigated. Results were linear in the concentration range 0.1-250 µg/L for all compounds of interest, with R 2  > 0.9950. Limits of detection were in the range 0.1-0.4 μg/kg, and limits of quantitation were between 0.5 μg/kg and 1.0 μg/kg. The mean recoveries for negative samples at three spiked concentrations were in the range 87.9%-102.4%, and the intra-day precision and inter-day precision were in the ranges 2.1-8.2% and 4.8-11.2%, respectively. This method is accurate and sensitive, and had good clean-up characteristics, which might apply to screening and quantitation of target bisphenols and alkylphenols in hotpot seasoning. Copyright © 2018 Elsevier Ltd. All rights reserved.

A highly sensitive magnetic biosensor for detection and quantification of anticancer drugs tagged to superparamagnetic nanoparticles

NASA Astrophysics Data System (ADS)

Wingo, J.; Devkota, J.; Mai, T. T. T.; Nguyen, X. P.; Mukherjee, P.; Srikanth, H.; Phan, M. H.; Vietnam Academy of Science and Technology Collaboration; University of South Florida Team

2014-03-01

A precise detection of low concentrations of biomolecules attached to magnetic nanoparticles in complex biological systems is a challenging task and requires biosensors with improved sensitivity. Here, we present a highly sensitive magnetic biosensor based on the magneto-reactance (MX) effect of a Co65Fe4Ni2Si15B14 amorphous ribbon with nanohole-patterned surface for detection and quantification of anticancer drugs (Curcumin) tagged to Fe3O4 nanoparticles. The detection and quantification of Curcumin were assessed by the change in MX of the ribbon subject to varying concentrations of the functionalized Fe3O4 nanoparticles. A high capacity of the MX-based biosensor in quantitative analysis of the nanoparticles was achieved in the range of 0 - 50 ng/ml, beyond which the detection sensitivity (η) remained unchanged. The η of the biosensor reached an extremely high value of 30%, which is about 4-5 times higher than that of a magneto-impedance (MI) based biosensor. This biosensor is well suited for detection of low-concentration magnetic biomarkers in biological systems. This work was supported by was supported by the Florida Cluster for Advanced Smart Sensor Technologies, USAMRMC (Grant # W81XWH-07-1-0708), and the NSF-funded REU program at the USF.

Automatic Stem Cell Detection in Microscopic Whole Mouse Cryo-imaging

PubMed Central

Wuttisarnwattana, Patiwet; Gargesha, Madhusudhana; Hof, Wouter van’t; Cooke, Kenneth R.

2016-01-01

With its single cell sensitivity over volumes as large as or larger than a mouse, cryo-imaging enables imaging of stem cell biodistribution, homing, engraftment, and molecular mechanisms. We developed and evaluated a highly automated software tool to detect fluorescently labeled stem cells within very large (~200GB) cryo-imaging datasets. Cell detection steps are: preprocess, remove immaterial regions, spatially filter to create features, identify candidate pixels, classify pixels using bagging decision trees, segment cell patches, and perform 3D labeling. There are options for analysis and visualization. To train the classifier, we created synthetic images by placing realistic digital cell models onto cryo-images of control mice devoid of cells. Very good cell detection results were (precision=98.49%, recall=99.97%) for synthetic cryo-images, (precision=97.81%, recall=97.71%) for manually evaluated, actual cryo-images, and <1% false positives in control mice. An α-multiplier applied to features allows one to correct for experimental variations in cell brightness due to labeling. On dim cells (37% of standard brightness), with correction, we improved recall (49.26%→99.36%) without a significant drop in precision (99.99%→99.75%). With tail vein injection, multipotent adult progenitor cells in a graft-versus-host-disease model in the first days post injection were predominantly found in lung, liver, spleen, and bone marrow. Distribution was not simply related to blood flow. The lung contained clusters of cells while other tissues contained single cells. Our methods provided stem cell distribution anywhere in mouse with single cell sensitivity. Methods should provide a rational means of evaluating dosing, delivery methods, cell enhancements, and mechanisms for therapeutic cells. PMID:26552080

Measurement of atmospheric ozone by cavity ring-down spectroscopy.

PubMed

Washenfelder, R A; Wagner, N L; Dube, W P; Brown, S S

2011-04-01

Ozone plays a key role in both the Earth's radiative budget and photochemistry. Accurate, robust analytical techniques for measuring its atmospheric abundance are of critical importance. Cavity ring-down spectroscopy has been successfully used for sensitive and accurate measurements of many atmospheric species. However, this technique has not been used for atmospheric measurements of ozone, because the strongest ozone absorption bands occur in the ultraviolet spectral region, where Rayleigh and Mie scattering cause significant cavity losses and dielectric mirror reflectivities are limited. Here, we describe a compact instrument that measures O3 by chemical conversion to NO2 in excess NO, with subsequent detection by cavity ring-down spectroscopy. This method provides a simple, accurate, and high-precision measurement of atmospheric ozone. The instrument consists of two channels. The sum of NO2 and converted O3 (defined as Ox) is measured in the first channel, while NO2 alone is measured in the second channel. NO2 is directly detected in each channel by cavity ring-down spectroscopy with a laser diode light source at 404 nm. The limit of detection for O3 is 26 pptv (2 sigma precision) at 1 s time resolution. The accuracy of the measurement is ±2.2%, with the largest uncertainty being the effective NO2 absorption cross-section. The linear dynamic range of the instrument has been verified from the detection limit to above 200 ppbv (r2>99.99%). The observed precision on signal (2 sigma) with 41 ppbv O3 is 130 pptv in 1 s. Comparison of this instrument to UV absorbance instruments for ambient O3 concentrations shows linear agreement (r2=99.1%) with slope of 1.012±0.002.

Inflationary tensor perturbations after BICEP2.

PubMed

Caligiuri, Jerod; Kosowsky, Arthur

2014-05-16

The measurement of B-mode polarization of the cosmic microwave background at large angular scales by the BICEP experiment suggests a stochastic gravitational wave background from early-Universe inflation with a surprisingly large amplitude. The power spectrum of these tensor perturbations can be probed both with further measurements of the microwave background polarization at smaller scales and also directly via interferometry in space. We show that sufficiently sensitive high-resolution B-mode measurements will ultimately have the ability to test the inflationary consistency relation between the amplitude and spectrum of the tensor perturbations, confirming their inflationary origin. Additionally, a precise B-mode measurement of the tensor spectrum will predict the tensor amplitude on solar system scales to 20% accuracy for an exact power-law tensor spectrum, so a direct detection will then measure the running of the tensor spectral index to high precision.

Segmented Detector Calibration Techniques for the PROSPECT Experiment

NASA Astrophysics Data System (ADS)

Davee, Daniel; Prospect Collaboration

2016-03-01

PROSPECT will make the most precise measurement of the 235U anti-neutrino spectrum to date and search for eV-scale sterile neutrinos. The proposed detector is composed of 120 6Li loaded liquid scintillator filled cells, and uses Inverse Beta Decay (IBD) ν + p -->e+ + n to detect reactor anti-neutrinos. Because the positron produced in IBD carries most of the ν energy, the response throughout the entire segmented detector to electron-like energy depositions must be determined with high precision via an extensive calibration program. To this end the detector is designed to allow for the insertion of both optical and radioactive sources to test each performance of cell individually without changing the optical response. In addition to these measures, cosmogenic sources will be used to probe energy response of the detector at high energies.

Towards accurate radial velocities from early type spectra in the framework of an ESO key programme

NASA Astrophysics Data System (ADS)

Verschueren, Werner; David, M.; Hensberge, Herman

In order to elucidate the internal kinematics in very young stellar groups, a dedicated machinery was set up, which made it possible to proceed from actual observations to reductions and correlation analysis to the ultimate derivation of early-type stellar radial velocities (RVs) with the requisite precision. The following ingredients are found to be essential to obtain RVs of early-type stars at the 1-km/s level of precision: high-resolution, high-S/N spectra covering a large wavelength range; maximal reduction of observational errors and the use of optimal reduction procedures; the intelligent use of a versatile cross-correlation package; and comparison of velocities derived from different regions of the spectrum in order to detect systematic mismatches between object and template spectrum in some of the lines.

Down syndrome detection from facial photographs using machine learning techniques

NASA Astrophysics Data System (ADS)

Zhao, Qian; Rosenbaum, Kenneth; Sze, Raymond; Zand, Dina; Summar, Marshall; Linguraru, Marius George

2013-02-01

Down syndrome is the most commonly occurring chromosomal condition; one in every 691 babies in United States is born with it. Patients with Down syndrome have an increased risk for heart defects, respiratory and hearing problems and the early detection of the syndrome is fundamental for managing the disease. Clinically, facial appearance is an important indicator in diagnosing Down syndrome and it paves the way for computer-aided diagnosis based on facial image analysis. In this study, we propose a novel method to detect Down syndrome using photography for computer-assisted image-based facial dysmorphology. Geometric features based on facial anatomical landmarks, local texture features based on the Contourlet transform and local binary pattern are investigated to represent facial characteristics. Then a support vector machine classifier is used to discriminate normal and abnormal cases; accuracy, precision and recall are used to evaluate the method. The comparison among the geometric, local texture and combined features was performed using the leave-one-out validation. Our method achieved 97.92% accuracy with high precision and recall for the combined features; the detection results were higher than using only geometric or texture features. The promising results indicate that our method has the potential for automated assessment for Down syndrome from simple, noninvasive imaging data.

Estimate of within population incremental selection through branch imbalance in lineage trees

PubMed Central

Liberman, Gilad; Benichou, Jennifer I.C.; Maman, Yaakov; Glanville, Jacob; Alter, Idan; Louzoun, Yoram

2016-01-01

Incremental selection within a population, defined as limited fitness changes following mutation, is an important aspect of many evolutionary processes. Strongly advantageous or deleterious mutations are detected using the synonymous to non-synonymous mutations ratio. However, there are currently no precise methods to estimate incremental selection. We here provide for the first time such a detailed method and show its precision in multiple cases of micro-evolution. The proposed method is a novel mixed lineage tree/sequence based method to detect within population selection as defined by the effect of mutations on the average number of offspring. Specifically, we propose to measure the log of the ratio between the number of leaves in lineage trees branches following synonymous and non-synonymous mutations. The method requires a high enough number of sequences, and a large enough number of independent mutations. It assumes that all mutations are independent events. It does not require of a baseline model and is practically not affected by sampling biases. We show the method's wide applicability by testing it on multiple cases of micro-evolution. We show that it can detect genes and inter-genic regions using the selection rate and detect selection pressures in viral proteins and in the immune response to pathogens. PMID:26586802

A sensitive and rapid determination of ranitidine in human plasma by HPLC with fluorescence detection and its application for a pharmacokinetic study.

PubMed

Ulu, Sevgi Tatar; Tuncel, Muzaffer

2012-04-01

A novel precolumn derivatization reversed-phase high-performance liquid chromatography method with fluorescence detection is described for the determination of ranitidine in human plasma. The method was based on the reaction of ranitidine with 4-fluoro-7-nitrobenzo-2-oxa-1,3-diazole forming yellow colored fluorescent product. The separation was achieved on a C(18) column using methanol-water (60:40, v/v) mobile phase. Fluorescence detection was used at the excitation and emission of 458 and 521 nm, respectively. Lisinopril was utilized as an internal standard. The flow rate was 1.2 mL/min. Ranitidine and lisinopril appeared at 3.24 and 2.25 min, respectively. The method was validated for system suitability, precision, accuracy, linearity, limit of detection, limit of quantification, recovery and robustness. Intra- and inter-day precisions of the assays were in the range of 0.01-0.44%. The assay was linear over the concentration range of 50-2000 ng/mL. The mean recovery was determined to be 96.40 ± 0.02%. This method was successfully applied to a pharmacokinetic study after oral administration of a dose (150 mg) of ranitidine. © The Author [2012]. Published by Oxford University Press. All rights reserved.

A sensitive assay for urinary cocaine metabolite benzoylecgonine shows more positive results and longer half-lives than those using traditional cut-offs.

PubMed

Nickley, Joyce; Pesce, Amadeo J; Krock, Kevin

2017-08-01

Cocaine is a common drug of abuse. To detect its use, a screening detection concentration for the cocaine metabolite benzoylecgonine is commonly set at 150 ng/mL and its confirmatory cut-off is set at 100 ng/mL. Studies have suggested that these cut-offs may be set too high, allowing some patients with this substance abuse problem to be missed or improperly monitored. With the advent of liquid chromatography-tandem mass spectrometry (LC-MS/MS) technology it is possible to reliably detect and quantify lower concentrations of its metabolite benzoylecgonine as part of a larger drug panel. One purpose of the study was to establish if there was a significant increase in detection of cocaine use with a ten-fold more sensitive cut-off. A very sensitive dilute and shoot assay for benzoylecgonine was developed with a lower limit of quantitation of 5 ng/mL. Validation of the 5 ng/mL cut-off was achieved by plotting all the positive cocaine observations as a frequency distribution on a logarithmic scale. The number of positive results with measurable concentrations below the typical industry 100 ng/mL cut-off level but above the high sensitivity 5 ng/mL cut-off level was observed to be 51.9% of the observed positives. The lower cut-off also allowed a re-evaluation of the window of detection after cessation of use. It was observed to be between 17 and 22 days. © 2016 Precision Diagnostics, LLC. Drug Testing and Analysis published by John Wiley & Sons, Ltd. © 2016 Precision Diagnostics, LLC. Drug Testing and Analysis published by John Wiley & Sons, Ltd.

Development of a high-throughput detection system for HIV-1 using real-time NASBA based on molecular beacons

NASA Astrophysics Data System (ADS)

van Beuningen, Rinie; Marras, Salvatore A.; Kramer, Fred R.; Oosterlaken, Tom; Weusten, Jos; Borst, G.; van de Wiel, Paul

2001-04-01

HIV-1 viral load assays require accuracy and sensitivity at low RNA levels with the capability to detect all subtypes. Furthermore, the assay should be easy to perform and fast to be useful for routine diagnostics. In order to meet these demands we have combined isothermal NASBA amplification with molecular beacon probes for real-time detection and quantitation of HIV-1 RNA. Quantitation is based on co-amplification of the HIV-1 RNA in the clinical sample and a synthetic calibrator RNA which is amplified by the same primer set but detected with a differently labeled molecular beacon. The entire procedure is simple and analysis of 48 samples requires less than 1» hours with minimal hands-on time. A fluorescent plate reader is used for real-time detection and isothermal amplification. The linearity and precision of the assay was determined with the VQC HIV-1 type B standard of the Central Laboratory of the Dutch Red Cross Blood Banks, The Netherlands. Sensitivity was shown to be 50 copies per ml (cps/ml). The average assay precision was 0,19 log10 over a range of 100-300,000 cps/ml tested at nine concentrations. The linearity of dilution series of 15 cultured HIV-1 gag clades A-H was shown. The specificity was 100% on non HIV-1 samples HIV-2, HTLV-1 and HTLV-2. The assay robustness in terms of valid results was 99%. In conclusion, the new real-time NASBA assay meets state-of-the-art HIV-1 viral load performance requirements combined with a high level of user convenience.

Fully convolutional neural networks for polyp segmentation in colonoscopy

NASA Astrophysics Data System (ADS)

Brandao, Patrick; Mazomenos, Evangelos; Ciuti, Gastone; Caliò, Renato; Bianchi, Federico; Menciassi, Arianna; Dario, Paolo; Koulaouzidis, Anastasios; Arezzo, Alberto; Stoyanov, Danail

2017-03-01

Colorectal cancer (CRC) is one of the most common and deadliest forms of cancer, accounting for nearly 10% of all forms of cancer in the world. Even though colonoscopy is considered the most effective method for screening and diagnosis, the success of the procedure is highly dependent on the operator skills and level of hand-eye coordination. In this work, we propose to adapt fully convolution neural networks (FCN), to identify and segment polyps in colonoscopy images. We converted three established networks into a fully convolution architecture and fine-tuned their learned representations to the polyp segmentation task. We validate our framework on the 2015 MICCAI polyp detection challenge dataset, surpassing the state-of-the-art in automated polyp detection. Our method obtained high segmentation accuracy and a detection precision and recall of 73.61% and 86.31%, respectively.

Piezoresistive microcantilever based lab-on-a-chip system for detection of macronutrients in the soil

NASA Astrophysics Data System (ADS)

Patkar, Rajul S.; Ashwin, Mamta; Rao, V. Ramgopal

2017-12-01

Monitoring of soil nutrients is very important in precision agriculture. In this paper, we have demonstrated a micro electro mechanical system based lab-on-a-chip system for detection of various soil macronutrients which are available in ionic form K+, NO3-, and H2PO4-. These sensors are highly sensitive piezoresistive silicon microcantilevers coated with a polymer matrix containing methyltridodecylammonium nitrate ionophore/ nitrate ionophore VI for nitrate sensing, 18-crown-6 ether for potassium sensing and Tributyltin chloride for phosphate detection. A complete lab-on-a-chip system integrating a highly sensitive current excited Wheatstone's bridge based portable electronic setup along with arrays of microcantilever devices mounted on a printed circuit board with a liquid flow cell for on the site experimentation for soil test has been demonstrated.

Stand-off laser Raman spectroscopy and its advancement in explosives detection

NASA Astrophysics Data System (ADS)

Liu, Sheng-run; Xue, Bin; Li, Yi-zhe; Wang, Hui

2017-10-01

The explosives detection has been a hot and difficult issue in the field of security it is particularly important to detect explosives quickly and reliably. There are many methods to detect explosives currently, stand-off Raman spectroscopy is one of the most promising and practical technologies, this technique can be used for non-contact and nondestructive detection, ensure the safety of attendants, at the same time the precision and speed of detection are also very high and be characterized by rapid response. This paper mainly gives an account of the fundamental principle of Raman spectroscopy, as well as recount major challenges of Standoff Laser Raman Spectroscopy applied in explosives detection and corresponding solutions. From the perspective of the system, this paper sums up related theories and techniques of the excitation laser and telescopic system etc.. Ultimately, a brief analysis and summary of the development trend of this technology is given.

Ship detection in optical remote sensing images based on deep convolutional neural networks

NASA Astrophysics Data System (ADS)

Yao, Yuan; Jiang, Zhiguo; Zhang, Haopeng; Zhao, Danpei; Cai, Bowen

2017-10-01

Automatic ship detection in optical remote sensing images has attracted wide attention for its broad applications. Major challenges for this task include the interference of cloud, wave, wake, and the high computational expenses. We propose a fast and robust ship detection algorithm to solve these issues. The framework for ship detection is designed based on deep convolutional neural networks (CNNs), which provide the accurate locations of ship targets in an efficient way. First, the deep CNN is designed to extract features. Then, a region proposal network (RPN) is applied to discriminate ship targets and regress the detection bounding boxes, in which the anchors are designed by intrinsic shape of ship targets. Experimental results on numerous panchromatic images demonstrate that, in comparison with other state-of-the-art ship detection methods, our method is more efficient and achieves higher detection accuracy and more precise bounding boxes in different complex backgrounds.

A PVC/polypyrrole sensor designed for beef taste detection using electrochemical methods and sensory evaluation.

PubMed

Zhu, Lingtao; Wang, Xiaodan; Han, Yunxiu; Cai, Yingming; Jin, Jiahui; Wang, Hongmei; Xu, Liping; Wu, Ruijia

2018-03-01

An electrochemical sensor for detection of beef taste was designed in this study. This sensor was based on the structure of polyvinyl chloride/polypyrrole (PVC/PPy), which was polymerized onto the surface of a platinum (Pt) electrode to form a Pt-PPy-PVC film. Detecting by electrochemical methods, the sensor was well characterized by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The sensor was applied to detect 10 rib-eye beef samples and the accuracy of the new sensor was validated by sensory evaluation and ion sensor detection. Several cluster analysis methods were used in the study to distinguish the beef samples. According to the obtained results, the designed sensor showed a high degree of association of electrochemical detection and sensory evaluation, which proved a fast and precise sensor for beef taste detection. Copyright © 2017 Elsevier Ltd. All rights reserved.

Infrared dim target detection based on visual attention

NASA Astrophysics Data System (ADS)

Wang, Xin; Lv, Guofang; Xu, Lizhong

2012-11-01

Accurate and fast detection of infrared (IR) dim target has very important meaning for infrared precise guidance, early warning, video surveillance, etc. Based on human visual attention mechanisms, an automatic detection algorithm for infrared dim target is presented. After analyzing the characteristics of infrared dim target images, the method firstly designs Difference of Gaussians (DoG) filters to compute the saliency map. Then the salient regions where the potential targets exist in are extracted by searching through the saliency map with a control mechanism of winner-take-all (WTA) competition and inhibition-of-return (IOR). At last, these regions are identified by the characteristics of the dim IR targets, so the true targets are detected, and the spurious objects are rejected. The experiments are performed for some real-life IR images, and the results prove that the proposed method has satisfying detection effectiveness and robustness. Meanwhile, it has high detection efficiency and can be used for real-time detection.

Determination of plutonium in spent nuclear fuel using high resolution X-ray

DOE PAGES

McIntosh, Kathryn G.; Reilly, Sean D.; Havrilla, George J.

2015-05-30

Characterization of Pu is an essential aspect of safeguards operations at nuclear fuel reprocessing facilities. A novel analysis technique called hiRX (high resolution X-ray) has been developed for the direct measurement of Pu in spent nuclear fuel dissolver solutions. hiRX is based on monochromatic wavelength dispersive X-ray fluorescence (MWDXRF), which provides enhanced sensitivity and specificity compared with conventional XRF techniques. A breadboard setup of the hiRX instrument was calibrated using spiked surrogate spent fuel (SSF) standards prepared as dried residues. Samples of actual spent fuel were utilized to evaluate the performance of the hiRX. The direct detection of just 39more » ng of Pu is demonstrated. Initial quantitative results, with error of 4–27% and precision of 2% relative standard deviation (RSD), were obtained for spent fuel samples. The limit of detection for Pu (100 s) within an excitation spot of 200 μm diameter was 375 pg. This study demonstrates the potential for the hiRX technique to be utilized for the rapid, accurate, and precise determination of Pu. Moreover, the results highlight the analytical capability of hiRX for other applications requiring sensitive and selective nondestructive analyses.« less

Three-dimensional imaging of individual point defects using selective detection angles in annular dark field scanning transmission electron microscopy.

PubMed

Johnson, Jared M; Im, Soohyun; Windl, Wolfgang; Hwang, Jinwoo

2017-01-01

We propose a new scanning transmission electron microscopy (STEM) technique that can realize the three-dimensional (3D) characterization of vacancies, lighter and heavier dopants with high precision. Using multislice STEM imaging and diffraction simulations of β-Ga 2 O 3 and SrTiO 3 , we show that selecting a small range of low scattering angles can make the contrast of the defect-containing atomic columns substantially more depth-dependent. The origin of the depth-dependence is the de-channeling of electrons due to the existence of a point defect in the atomic column, which creates extra "ripples" at low scattering angles. The highest contrast of the point defect can be achieved when the de-channeling signal is captured using the 20-40mrad detection angle range. The effect of sample thickness, crystal orientation, local strain, probe convergence angle, and experimental uncertainty to the depth-dependent contrast of the point defect will also be discussed. The proposed technique therefore opens new possibilities for highly precise 3D structural characterization of individual point defects in functional materials. Copyright © 2016 Elsevier B.V. All rights reserved.

Application of seismic interferometric migration for shallow seismic high precision data processing: A case study in the Shenhu area

NASA Astrophysics Data System (ADS)

Wei, Jia; Liu, Huaishan; Xing, Lei; Du, Dong

2018-02-01

The stability of submarine geological structures has a crucial influence on the construction of offshore engineering projects and the exploitation of seabed resources. Marine geologists should possess a detailed understanding of common submarine geological hazards. Current marine seismic exploration methods are based on the most effective detection technologies. Therefore, current research focuses on improving the resolution and precision of shallow stratum structure detection methods. In this article, the feasibility of shallow seismic structure imaging is assessed by building a complex model, and differences between the seismic interferometry imaging method and the traditional imaging method are discussed. The imaging effect of the model is better for shallow layers than for deep layers because coherent noise produced by this method can result in an unsatisfactory imaging effect for deep layers. The seismic interference method has certain advantages for geological structural imaging of shallow submarine strata, which indicates continuous horizontal events, a high resolution, a clear fault, and an obvious structure boundary. The effects of the actual data applied to the Shenhu area can fully illustrate the advantages of the method. Thus, this method has the potential to provide new insights for shallow submarine strata imaging in the area.

Direct high-precision measurement of the magnetic moment of the proton.

PubMed

Mooser, A; Ulmer, S; Blaum, K; Franke, K; Kracke, H; Leiteritz, C; Quint, W; Rodegheri, C C; Smorra, C; Walz, J

2014-05-29

One of the fundamental properties of the proton is its magnetic moment, µp. So far µp has been measured only indirectly, by analysing the spectrum of an atomic hydrogen maser in a magnetic field. Here we report the direct high-precision measurement of the magnetic moment of a single proton using the double Penning-trap technique. We drive proton-spin quantum jumps by a magnetic radio-frequency field in a Penning trap with a homogeneous magnetic field. The induced spin transitions are detected in a second trap with a strong superimposed magnetic inhomogeneity. This enables the measurement of the spin-flip probability as a function of the drive frequency. In each measurement the proton's cyclotron frequency is used to determine the magnetic field of the trap. From the normalized resonance curve, we extract the particle's magnetic moment in terms of the nuclear magneton: μp = 2.792847350(9)μN. This measurement outperforms previous Penning-trap measurements in terms of precision by a factor of about 760. It improves the precision of the forty-year-old indirect measurement, in which significant theoretical bound state corrections were required to obtain µp, by a factor of 3. By application of this method to the antiproton magnetic moment, the fractional precision of the recently reported value can be improved by a factor of at least 1,000. Combined with the present result, this will provide a stringent test of matter/antimatter symmetry with baryons.

Automated detection and labeling of high-density EEG electrodes from structural MR images.

PubMed

Marino, Marco; Liu, Quanying; Brem, Silvia; Wenderoth, Nicole; Mantini, Dante

2016-10-01

Accurate knowledge about the positions of electrodes in electroencephalography (EEG) is very important for precise source localizations. Direct detection of electrodes from magnetic resonance (MR) images is particularly interesting, as it is possible to avoid errors of co-registration between electrode and head coordinate systems. In this study, we propose an automated MR-based method for electrode detection and labeling, particularly tailored to high-density montages. Anatomical MR images were processed to create an electrode-enhanced image in individual space. Image processing included intensity non-uniformity correction, background noise and goggles artifact removal. Next, we defined a search volume around the head where electrode positions were detected. Electrodes were identified as local maxima in the search volume and registered to the Montreal Neurological Institute standard space using an affine transformation. This allowed the matching of the detected points with the specific EEG montage template, as well as their labeling. Matching and labeling were performed by the coherent point drift method. Our method was assessed on 8 MR images collected in subjects wearing a 256-channel EEG net, using the displacement with respect to manually selected electrodes as performance metric. Average displacement achieved by our method was significantly lower compared to alternative techniques, such as the photogrammetry technique. The maximum displacement was for more than 99% of the electrodes lower than 1 cm, which is typically considered an acceptable upper limit for errors in electrode positioning. Our method showed robustness and reliability, even in suboptimal conditions, such as in the case of net rotation, imprecisely gathered wires, electrode detachment from the head, and MR image ghosting. We showed that our method provides objective, repeatable and precise estimates of EEG electrode coordinates. We hope our work will contribute to a more widespread use of high-density EEG as a brain-imaging tool.

Automated detection and labeling of high-density EEG electrodes from structural MR images

NASA Astrophysics Data System (ADS)

Marino, Marco; Liu, Quanying; Brem, Silvia; Wenderoth, Nicole; Mantini, Dante

2016-10-01

Objective. Accurate knowledge about the positions of electrodes in electroencephalography (EEG) is very important for precise source localizations. Direct detection of electrodes from magnetic resonance (MR) images is particularly interesting, as it is possible to avoid errors of co-registration between electrode and head coordinate systems. In this study, we propose an automated MR-based method for electrode detection and labeling, particularly tailored to high-density montages. Approach. Anatomical MR images were processed to create an electrode-enhanced image in individual space. Image processing included intensity non-uniformity correction, background noise and goggles artifact removal. Next, we defined a search volume around the head where electrode positions were detected. Electrodes were identified as local maxima in the search volume and registered to the Montreal Neurological Institute standard space using an affine transformation. This allowed the matching of the detected points with the specific EEG montage template, as well as their labeling. Matching and labeling were performed by the coherent point drift method. Our method was assessed on 8 MR images collected in subjects wearing a 256-channel EEG net, using the displacement with respect to manually selected electrodes as performance metric. Main results. Average displacement achieved by our method was significantly lower compared to alternative techniques, such as the photogrammetry technique. The maximum displacement was for more than 99% of the electrodes lower than 1 cm, which is typically considered an acceptable upper limit for errors in electrode positioning. Our method showed robustness and reliability, even in suboptimal conditions, such as in the case of net rotation, imprecisely gathered wires, electrode detachment from the head, and MR image ghosting. Significance. We showed that our method provides objective, repeatable and precise estimates of EEG electrode coordinates. We hope our work will contribute to a more widespread use of high-density EEG as a brain-imaging tool.

Construction and quality assurance of large area resistive strip Micromegas for the upgrade of the ATLAS Muon Spectrometer at LHC/CERN

NASA Astrophysics Data System (ADS)

Lösel, P.

2017-06-01

Large area Micromegas detectors will be employed for the first time in high-energy physics experiments. To cope with increasing background rates, associated with the steadily increasing luminosity of LHC to 10 times design luminosity, the present detector technology in the current innermost stations of the muon endcap system of the ATLAS experiment (the Small Wheel), will be replaced in 2019/2020 by resistive strip Micromegas and small strip TGC detectors. Both technologies will provide tracking and trigger information. In the "New Small Wheel" the Micromegas will be arranged in eight detection layers built of trapezoidally shaped quadruplets of four different sizes covering in total about 1200 m2 of detection plane. In order to achieve 15 % transverse momentum resolution for 1 TeV muons, a challenging mechanical precision is required in the construction of each active plane, with an alignment of the readout strips at the level of 30 μm RMS along the precision coordinate and 80 μm RMS perpendicular to the plane. Each individual Micromegas plane must achieve a spatial resolution better than 100 μm at background rates up to 15 kHz/cm2 while being operated in an inhomogeneous magnetic field (B <= 0.3 T). The required mechanical precision for the production of the components and their assembly, on such large area detectors, is a key point and must be controlled during construction and integration. Particularly the alignment of the readout strips within a quadruplet appears to be demanding. The readout strips are etched on PCB boards using photolithographic processes. Depending on the type of the module, 3 or 5 PCB boards need to be joined and precisely aligned to form a full readout plane. The precision in the alignment is reached either by use of precision mechanical holes or by optical masks, both referenced to the strip patterns. Assembly procedures have been developed to build the single panels with the required mechanical precision and to assemble them in a module including the four metallic micro-meshes. Methods to confirm the precision of components and assembly are based on precise optical devices and X-ray or cosmic muon investigations. We will report on the construction procedures for the Micromegas quadruplets, on the quality control procedures and results, and on the assembly and calibration methods.

2-Micron Pulsed Direct Detection IPDA Lidar for Atmospheric CO2 Measurement

NASA Technical Reports Server (NTRS)

Yu, Jirong; Petros, Mulugeta; Refaat, Tamer; Reithmaier, Karl; Remus, Ruben; Singh, Upendra; Johnson, Will; Boyer, Charlie; Fay, James; Johnston, Susan;

Single-Electron Detection and Spectroscopy via Relativistic Cyclotron Radiation.

PubMed

Asner, D M; Bradley, R F; de Viveiros, L; Doe, P J; Fernandes, J L; Fertl, M; Finn, E C; Formaggio, J A; Furse, D; Jones, A M; Kofron, J N; LaRoque, B H; Leber, M; McBride, E L; Miller, M L; Mohanmurthy, P; Monreal, B; Oblath, N S; Robertson, R G H; Rosenberg, L J; Rybka, G; Rysewyk, D; Sternberg, M G; Tedeschi, J R; Thümmler, T; VanDevender, B A; Woods, N L

2015-04-24

It has been understood since 1897 that accelerating charges must emit electromagnetic radiation. Although first derived in 1904, cyclotron radiation from a single electron orbiting in a magnetic field has never been observed directly. We demonstrate single-electron detection in a novel radio-frequency spectrometer. The relativistic shift in the cyclotron frequency permits a precise electron energy measurement. Precise beta electron spectroscopy from gaseous radiation sources is a key technique in modern efforts to measure the neutrino mass via the tritium decay end point, and this work demonstrates a fundamentally new approach to precision beta spectroscopy for future neutrino mass experiments.

Automated Inspection of Defects in Optical Fiber Connector End Face Using Novel Morphology Approaches.

PubMed

Mei, Shuang; Wang, Yudan; Wen, Guojun; Hu, Yang

2018-05-03

Increasing deployment of optical fiber networks and the need for reliable high bandwidth make the task of inspecting optical fiber connector end faces a crucial process that must not be neglected. Traditional end face inspections are usually performed by manual visual methods, which are low in efficiency and poor in precision for long-term industrial applications. More seriously, the inspection results cannot be quantified for subsequent analysis. Aiming at the characteristics of typical defects in the inspection process for optical fiber end faces, we propose a novel method, “difference of min-max ranking filtering” (DO2MR), for detection of region-based defects, e.g., dirt, oil, contamination, pits, and chips, and a special model, a “linear enhancement inspector” (LEI), for the detection of scratches. The DO2MR is a morphology method that intends to determine whether a pixel belongs to a defective region by comparing the difference of gray values of pixels in the neighborhood around the pixel. The LEI is also a morphology method that is designed to search for scratches at different orientations with a special linear detector. These two approaches can be easily integrated into optical inspection equipment for automatic quality verification. As far as we know, this is the first time that complete defect detection methods for optical fiber end faces are available in the literature. Experimental results demonstrate that the proposed DO2MR and LEI models yield good comprehensive performance with high precision and accepted recall rates, and the image-level detection accuracies reach 96.0 and 89.3%, respectively.

Chemical patterning on preformed porous silicon photonic crystals: towards multiplex detection of protease activity at precise positions†Electronic supplementary information (ESI) available: SEM images, XPS result and more optical reflectivity data. See DOI: 10.1039/c4tb00281dClick here for additional data file.

PubMed

Zhu, Ying; Soeriyadi, Alexander H; Parker, Stephen G; Reece, Peter J; Gooding, J Justin

2014-06-21

Porous silicon (PSi) rugate filters modified with alkyne-terminated monolayers were chemically patterned using a combination of photolithography of photoresist and click chemistry. Two chemical functionalities were obtained by conjugating, via click reactions, ethylene glycol moieties containing two different terminal groups to discrete areas towards the exterior of a PSi rugate filter. The patterning of biological species to the functionalized surface was demonstrated through the conjugation of fluorescein isothiocyanate labelled bovine serum albumin (FITC-BSA). Fluorescence microscopy showed selective positioning of FITC-BSA at discretely functionalized areas. Meanwhile, the optical information from precisely defined positions on the patterned surface was monitored by optical reflectivity measurements. The optical measurements revealed successful step-wise chemical functionalization followed by immobilization of gelatin. Multiplex detection of protease activity from different array elements on the patterned surface was demonstrated by monitoring the blue shifts in the reflectivity spectra resulted from the digestion of gelatin by subtilisin. Precise information from both individual elements and average population was acquired. This technique is important for the development of PSi into a microarray platform for highly parallel biosensing applications, especially for cell-based assays.

Analysis of 10 metabolites of polymethoxyflavones with high sensitivity by electrochemical detection in high-performance liquid chromatography.

PubMed

Zheng, Jinkai; Bi, Jinfeng; Johnson, David; Sun, Yue; Song, Mingyue; Qiu, Peiju; Dong, Ping; Decker, Eric; Xiao, Hang

2015-01-21

Polymethoxyflavones (PMFs) have been known as a type of bioactive flavones that possess various beneficial biological functions. Accumulating evidence demonstrated that the metabolites of PMFs, that is, hydroxyl PMFs (OH-PMFs), had more potent beneficial biological effects than their corresponding parent PMFs. To facilitate the further identification and quantification of OH-PMFs in biological samples, the aim of this study was to develop a methodology for the simultaneous determination of 10 OH-PMFs using high-performance liquid chromatography (HPLC) coupled with electrochemistry detection. The HPLC profiles of these 10 OH-PMFs affected by different chromatographic parameters (different organic composition in mobile phases, the concentration of trifluoroacetic acid, and the concentration of ammonium acetate) are fully discussed in this study. The optimal condition was selected for the following validation studies. The linearity of calibration curves, accuracy, and precision (intra- and interday) at three concentration levels (low, middle, and high concentration range) were verified. The regression equations were linear (r > 0.9992) over the range of 0.005-10 μM. The limit of detection for 10 OH-PMFs was in the range of 0.8-3.7 ng/mL (S/N = 3, 10 μL injection). The recovery rates ranged from 86.6 to 108.7%. The precisions of intraday and interday analyses were less than 7.37 and 8.63% for relative standard deviation, respectively. This validated method was applied for the analysis of a variety of samples containing OH-PMFs. This paper also gives an example of analyzing the metabolites of nobiletin in mouse urine using the developed method. The transformation from nobiletin to traces of 5-hydroxyl metabolites has been discovered by this effective method, and this is the first paper to report such an association.

Clinical utility of BOLD fMRI in preoperative work-up of epilepsy

PubMed Central

Ganesan, Karthik; Ursekar, Meher

2014-01-01

Surgical techniques have emerged as a viable therapeutic option in patients with drug refractory epilepsy. Pre-surgical evaluation of epilepsy requires a comprehensive, multiparametric, and multimodal approach for precise localization of the epileptogenic focus. Various non-invasive techniques are available at the disposal of the treating physician to detect the epileptogenic focus, which include electroencephalography (EEG), video-EEG, magnetic resonance imaging (MRI), functional MRI including blood oxygen level dependent (BOLD) techniques, single photon emission tomography (SPECT), and 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET). Currently, non-invasive high-resolution MR imaging techniques play pivotal roles in the preoperative detection of the seizure focus, and represent the foundation for successful epilepsy surgery. BOLD functional magnetic resonance imaging (fMRI) maps allow for precise localization of the eloquent cortex in relation to the seizure focus. This review article focuses on the clinical utility of BOLD (fMRI) in the pre-surgical work-up of epilepsy patients. PMID:24851002

Sealed position sensitive hard X-ray detector having large drift region for all sky camera with high angular resolution

NASA Technical Reports Server (NTRS)

Gorenstein, P.; Perlman, D.; Parsignault, D.; Burns, R.

1979-01-01

A sealed position sensitive proportional counter filled with two atmospheres of 95% xenon and 5% methane, and containing a drift region of 24 atm cm, has operated in a stable manner for many months. The detector contains G-10 frames to support the anode and cathode wires. The detector was sealed successfully by a combination of vacuum baking the G-10 frames at 150 C for two weeks followed by assembly into the detector in an environment of dry nitrogen, and the use of passive internal getters. The counter is intended for use with a circumferential cylindrical collimator. Together they provide a very broad field of view detection system with the ability to locate cosmic hard X-ray and soft gamma ray sources to an angular precision of a minute of arc. A set of instruments based on this principle have been proposed for satellites to detect and precisely locate cosmic gamma ray bursts.

Optimization and validation of a method for the determination of the refractive index of milk serum based on the reaction between milk and copper(II) sulfate to detect milk dilutions.

PubMed

Rezende, Patrícia Sueli; Carmo, Geraldo Paulo do; Esteves, Eduardo Gonçalves

2015-06-01

We report the use of a method to determine the refractive index of copper(II) serum (RICS) in milk as a tool to detect the fraudulent addition of water. This practice is highly profitable, unlawful, and difficult to deter. The method was optimized and validated and is simple, fast and robust. The optimized method yielded statistically equivalent results compared to the reference method with an accuracy of 0.4% and quadrupled analytical throughput. Trueness, precision (repeatability and intermediate precision) and ruggedness are determined to be satisfactory at a 95.45% confidence level. The expanded uncertainty of the measurement was ±0.38°Zeiss at the 95.45% confidence level (k=3.30), corresponding to 1.03% of the minimum measurement expected in adequate samples (>37.00°Zeiss). Copyright © 2015 Elsevier B.V. All rights reserved.

Rapid method for the determination of 14 isoflavones in food using UHPLC coupled to photo diode array detection.

PubMed

Shim, You-Shin; Yoon, Won-Jin; Hwang, Jin-Bong; Park, Hyun-Jin; Seo, Dongwon; Ha, Jaeho

2015-11-15

A rapid method for the determination of 14 types of isoflavones in food using ultra-high performance liquid chromatography (UHPLC) was validated in terms of precision, accuracy, sensitivity and linearity. The UHPLC separation was performed on a reverse-phase C18 column (particle size 2 μm, i.d. 2 mm, length 100 mm) using a photo diode array detector that was fixed to 260 nm. The limits of detection and quantification of the UHPLC analyses ranged from 0.03 to 0.33 mg kg(-1). The intra-day and inter-day precision of the individual isoflavones were less than 11.77% and calibration curves exhibited good linearity (r(2) = 0.99) within the tested ranges. These results suggest that the rapid method used in this study could be available to determine of 14 types of isoflavones in a variety of food such as soy bean, black bean, red bean and soybean paste. Copyright © 2015 Elsevier Ltd. All rights reserved.

CP-violating top quark couplings at future linear e^+e^- colliders

NASA Astrophysics Data System (ADS)

Bernreuther, W.; Chen, L.; García, I.; Perelló, M.; Poeschl, R.; Richard, F.; Ros, E.; Vos, M.

2018-02-01

We study the potential of future lepton colliders to probe violation of the CP symmetry in the top quark sector. In certain extensions of the Standard Model, such as the two-Higgs-doublet model (2HDM), sizeable anomalous top quark dipole moments can arise, which may be revealed by a precise measurement of top quark pair production. We present results from detailed Monte Carlo studies for the ILC at 500 GeV and CLIC at 380 GeV and use parton-level simulations to explore the potential of high-energy operation. We find that precise measurements in e^+e^- → t\\bar{t} production with subsequent decay to lepton plus jets final states can provide sufficient sensitivity to detect Higgs-boson-induced CP violation in a viable two-Higgs-doublet model. The potential of a linear e^+e^- collider to detect CP-violating electric and weak dipole form factors of the top quark exceeds the prospects of the HL-LHC by over an order of magnitude.

Prenatal diagnosis in a cystic fibrosis family: a combined molecular strategy for a precise diagnosis.

PubMed

Chávez-Saldaña, Margarita; García-Cavazos, Ricardo; Vigueras, Rosa María; Orozco, Lorena

2011-01-01

The high genetic heterogeneity in populations with a wide spectrum of mutations in the CF transmembrane conductance regulator gene (CFTR), makes the detection of mutations a very hard and difficult task, thereby limiting the accurate diagnosis of the disease, mainly in patients with uncharacterized mutations. Molecular strategies, like targeted identification of the most frequent CFTR mutations in Mexican population combined with linkage analysis using markers, is very useful for carrier detection and for prenatal diagnosis in affected families with CF. In this paper we show that the combination of methodologies was a crucial alternative to reach a precise prenatal CF diagnosis. We documented CF diagnosis in a 14th-week fetus combining the screening of the most common mutations in Mexican population with linkage analysis of two extragenic polymorphisms (XV2C/TaqI and KM19/PstI). We determined that the fetus inherited the PG542X mutation from its mother and an unknown mutation from its father through the chromosomal phases analysis.

Development of a Fabry-Perot Interferometer for Ultra-Precise Measurements of Column CO2

NASA Technical Reports Server (NTRS)

Wilson, Emily L.; Georgieva, Elena M.; Heaps, William S.

2005-01-01

A passive Fabry-Perot based instrument is described for detecting column CO2 through absorption measurements at 1.58 microns . In this design, solar flux reaches the instrument platform and is directed through two channels. In the first channel, transmittance fi5nges from a Fabry-Perot interferometer are aligned with CO2 absorption lines so that absorption due to CO2 is primarily detected. The second channel encompasses the same frequency region as the first, but is comparatively more sensitive to changes in the solar flux than absorption due to CO2. The ratio of these channels is sensitive to changes in the total CO2 column, but not to changes in solar flux. This inexpensive instrument will offer high precision measurements (error 4%) in a compact package. Design of this instrument and preliminary ground-based measurements of column CO2 are presented here as well as strategies for deployment on aircraft and satellite platforms.

A multifaceted FISH approach to study endogenous RNAs and DNAs in native nuclear and cell structures.

PubMed

Byron, Meg; Hall, Lisa L; Lawrence, Jeanne B

2013-01-01

Fluorescence in situ hybridization (FISH) is not a singular technique, but a battery of powerful and versatile tools for examining the distribution of endogenous genes and RNAs in precise context with each other and in relation to specific proteins or cell structures. This unit offers the details of highly sensitive and successful protocols that were initially developed largely in our lab and honed over a number of years. Our emphasis is on analysis of nuclear RNAs and DNA to address specific biological questions about nuclear structure, pre-mRNA metabolism, or the role of noncoding RNAs; however, cytoplasmic RNA detection is also discussed. Multifaceted molecular cytological approaches bring precise resolution and sensitive multicolor detection to illuminate the organization and functional roles of endogenous genes and their RNAs within the native structure of fixed cells. Solutions to several common technical pitfalls are discussed, as are cautions regarding the judicious use of digital imaging and the rigors of analyzing and interpreting complex molecular cytological results.

MR-based source localization for MR-guided HDR brachytherapy

NASA Astrophysics Data System (ADS)

Beld, E.; Moerland, M. A.; Zijlstra, F.; Viergever, M. A.; Lagendijk, J. J. W.; Seevinck, P. R.

2018-04-01

For the purpose of MR-guided high-dose-rate (HDR) brachytherapy, a method for real-time localization of an HDR brachytherapy source was developed, which requires high spatial and temporal resolutions. MR-based localization of an HDR source serves two main aims. First, it enables real-time treatment verification by determination of the HDR source positions during treatment. Second, when using a dummy source, MR-based source localization provides an automatic detection of the source dwell positions after catheter insertion, allowing elimination of the catheter reconstruction procedure. Localization of the HDR source was conducted by simulation of the MR artifacts, followed by a phase correlation localization algorithm applied to the MR images and the simulated images, to determine the position of the HDR source in the MR images. To increase the temporal resolution of the MR acquisition, the spatial resolution was decreased, and a subpixel localization operation was introduced. Furthermore, parallel imaging (sensitivity encoding) was applied to further decrease the MR scan time. The localization method was validated by a comparison with CT, and the accuracy and precision were investigated. The results demonstrated that the described method could be used to determine the HDR source position with a high accuracy (0.4–0.6 mm) and a high precision (⩽0.1 mm), at high temporal resolutions (0.15–1.2 s per slice). This would enable real-time treatment verification as well as an automatic detection of the source dwell positions.

A robust object-based shadow detection method for cloud-free high resolution satellite images over urban areas and water bodies

NASA Astrophysics Data System (ADS)

Tatar, Nurollah; Saadatseresht, Mohammad; Arefi, Hossein; Hadavand, Ahmad

2018-06-01

Unwanted contrast in high resolution satellite images such as shadow areas directly affects the result of further processing in urban remote sensing images. Detecting and finding the precise position of shadows is critical in different remote sensing processing chains such as change detection, image classification and digital elevation model generation from stereo images. The spectral similarity between shadow areas, water bodies, and some dark asphalt roads makes the development of robust shadow detection algorithms challenging. In addition, most of the existing methods work on pixel-level and neglect the contextual information contained in neighboring pixels. In this paper, a new object-based shadow detection framework is introduced. In the proposed method a pixel-level shadow mask is built by extending established thresholding methods with a new C4 index which enables to solve the ambiguity of shadow and water bodies. Then the pixel-based results are further processed in an object-based majority analysis to detect the final shadow objects. Four different high resolution satellite images are used to validate this new approach. The result shows the superiority of the proposed method over some state-of-the-art shadow detection method with an average of 96% in F-measure.

Precise, High-throughput Analysis of Bacterial Growth.

PubMed

Kurokawa, Masaomi; Ying, Bei-Wen

2017-09-19

Bacterial growth is a central concept in the development of modern microbial physiology, as well as in the investigation of cellular dynamics at the systems level. Recent studies have reported correlations between bacterial growth and genome-wide events, such as genome reduction and transcriptome reorganization. Correctly analyzing bacterial growth is crucial for understanding the growth-dependent coordination of gene functions and cellular components. Accordingly, the precise quantitative evaluation of bacterial growth in a high-throughput manner is required. Emerging technological developments offer new experimental tools that allow updates of the methods used for studying bacterial growth. The protocol introduced here employs a microplate reader with a highly optimized experimental procedure for the reproducible and precise evaluation of bacterial growth. This protocol was used to evaluate the growth of several previously described Escherichia coli strains. The main steps of the protocol are as follows: the preparation of a large number of cell stocks in small vials for repeated tests with reproducible results, the use of 96-well plates for high-throughput growth evaluation, and the manual calculation of two major parameters (i.e., maximal growth rate and population density) representing the growth dynamics. In comparison to the traditional colony-forming unit (CFU) assay, which counts the cells that are cultured in glass tubes over time on agar plates, the present method is more efficient and provides more detailed temporal records of growth changes, but has a stricter detection limit at low population densities. In summary, the described method is advantageous for the precise and reproducible high-throughput analysis of bacterial growth, which can be used to draw conceptual conclusions or to make theoretical observations.

The detection of cryptic Plasmodium infection among villagers in Attapeu province, Lao PDR

PubMed Central

Khattignavong, Phonepadith; Soundala, Pheovaly; Lorphachan, Lavy; Matsumoto-Takahashi, Emilie; Strobel, Michel; Reinharz, Daniel; Phommasansack, Manisack; Hongvanthong, Bouasy; Brey, Paul T.

2017-01-01

Background Although the malaria burden in the Lao PDR has gradually decreased, the elimination of malaria by 2030 presents many challenges. Microscopy and malaria rapid diagnostic tests (RDTs) are used to diagnose malaria in the Lao PDR; however, some studies have reported the prevalence of sub-microscopic Plasmodium infections or asymptomatic Plasmodium carriers in endemic areas. Thus, highly sensitive detection methods are needed to understand the precise malaria situation in these areas. Methodology/Principal findings A cross-sectional malaria field survey was conducted in 3 highly endemic malaria districts (Xaysetha, Sanamxay, Phouvong) in Attapeu province, Lao PDR in 2015, to investigate the precise malaria endemicity in the area; 719 volunteers from these villages participated in the survey. Microscopy, RDTs and a real-time nested PCR were used to detect Plasmodium infections and their results were compared. A questionnaire survey of all participants was also conducted to estimate risk factors of Plasmodium infection. Numbers of infections detected by the three methods were microscopy: P. falciparum (n = 1), P. vivax (n = 2); RDTs: P. falciparum (n = 2), P. vivax (n = 3); PCR: Plasmodium (n = 47; P. falciparum [n = 4], P. vivax [n = 41], mixed infection [n = 2]; 6.5%, 47/719). Using PCR as a reference, the sensitivity and specificity of microscopy were 33.3% and 100.0%, respectively, for detecting P. falciparum infection, and 7.0% and 100.0%, for detecting P. vivax infection. Among the 47 participants with parasitemia, only one had a fever (≥37.5°C) and 31 (66.0%) were adult males. Risk factors of Plasmodium infection were males and soldiers, whereas a risk factor of asymptomatic Plasmodium infection was a history of ≥3 malaria episodes. Conclusions/Significance There were many asymptomatic Plasmodium carriers in the study areas of Attapeu province in 2015. Adult males, probably soldiers, were at high risk for malaria infection. P. vivax, the dominant species, accounted for 87.2% of the Plasmodium infections among the participants. To achieve malaria elimination in the Lao PDR, highly sensitive diagnostic tests, including PCR-based diagnostic methods should be used, and plans targeting high-risk populations and elimination of P. vivax should be designed and implemented. PMID:29261647

Measurement precision in a series of visual fields acquired by the standard and fast versions of the Swedish interactive thresholding algorithm: analysis of large-scale data from clinics.

PubMed

Saunders, Luke J; Russell, Richard A; Crabb, David P

2015-01-01

Swedish Interactive Thresholding Algorithm (SITA) testing strategies for the Humphrey Field Analyzer have become a clinical standard. Measurements from SITA Fast are thought to be more variable than SITA Standard, yet some clinics routinely use SITA Fast because it is quicker. To examine the measurement precision of the 2 SITA strategies across a range of sensitivities using a large number of visual field (VF) series from 4 glaucoma clinics in England. Retrospective cohort study at Moorfields Eye Hospital in London, England; Gloucestershire Eye Unit at Cheltenham General Hospital; Queen Alexandra Hospital in Portsmouth, England; and the Calderdale and Huddersfield National Health Service Foundation Trust that included 66,974 Humphrey 24-2 SITA Standard VFs (10,124 eyes) and 19,819 Humphrey 24-2 SITA Fast VFs (3654 eyes) recorded between May 20, 1997, and September 20, 2012. Pointwise ordinary least squares linear regression of measured sensitivity over time was conducted using VF series of 1 random eye from each patient. Residuals from the regression were pooled according to fitted sensitivities. For each sensitivity (decibel) level, the standard deviation of the residuals was used to estimate measurement precision and were compared for SITA Standard and SITA Fast. Simulations of progression from different VF baselines were used to evaluate how different levels of precision would affect time to detect VF progression. Median years required to detect progression. Median (interquartile range) patient age, follow-up, and series lengths for SITA Standard were 64 (53-72) years, 6.0 (4.0-8.5) years, and 6 (4-8) VFs, respectively; for SITA Fast, medians (interquartile range) were 70 (61-78) years, 5.1 (3.2-7.3) years, and 5 (4-6) VFs. Measurement precision worsened as sensitivity decreased for both test strategies. In the 20 to 5 dB range, SITA Fast was less precise than SITA Standard; this difference was largest between 15 to 10 dB, where variability in both methods peaked. Translated to median time to detection, differences in measurement precision were negligible, suggesting minimal effects on time to detect progression. Although SITA Standard is a more precise testing algorithm than SITA Fast at lower VF sensitivities, it is unlikely to make a sizeable difference to improving the time to detect VF progression.

Application of 3D Laser Scanning Technology in Inspection and Dynamic Reserves Detection of Open-Pit Mine

NASA Astrophysics Data System (ADS)

Hu, Zhumin; Wei, Shiyu; Jiang, Jun

2017-10-01

The traditional open-pit mine mining rights verification and dynamic reserve detection means rely on the total station and RTK to collect the results of the turning point coordinates of mining surface contours. It resulted in obtaining the results of low precision and large error in the means that is limited by the traditional measurement equipment accuracy and measurement methods. The three-dimensional scanning technology can obtain the three-dimensional coordinate data of the surface of the measured object in a large area at high resolution. This paper expounds the commonly used application of 3D scanning technology in the inspection and dynamic reserve detection of open mine mining rights.

MINERVA: A Dedicated Observatory for Detection of Nearby Low-Mass Exoplanets

NASA Astrophysics Data System (ADS)

McCrady, Nate; Johnson, John; Wright, Jason; Wittenmyer, Robert A.; Blake, Cullen; Swift, Jonathan; Eastman, Jason D.; Plavchan, Peter; Riddle, Reed L.; Muirhead, Philip Steven; Bottom, Michael; Zhao, Ming; Beatty, Thomas G.

2015-01-01

Detection of low-mass planets around GKM stars requires sub-meter-per-second radial velocity precision. Stellar noise sources (starspots, oscillations, and granulation) necessitate high cadence observations. MINERVA is a dedicated observatory for velocimetric detection of low mass exoplanets orbiting nearby stars. Our array of four robotic 0.7-meter PlaneWave telescopes feeds a purpose-built, temperature-stabilized, iodine cell spectrometer from Callaghan Innovation. We will monitor bright, sun-like stars within 100 pc every clear night from Whipple Observatory on Mt Hopkins, Arizona. Each telescope is also equipped with an Andor CCD for followup photometry and education use. Commissioning is underway on the site and science observations will begin in early 2015.

Laser Spot Center Detection and Comparison Test

NASA Astrophysics Data System (ADS)

Zhu, Jun; Xu, Zhengjie; Fu, Deli; Hu, Cong

2018-04-01

High efficiency and precision of the pot center detection are the foundations of avionics instrument navigation and optics measurement basis for many applications. It has noticeable impact on overall system performance. Among them, laser spot detection is very important in the optical measurement technology. In order to improve the low accuracy of the spot center position, the algorithm is improved on the basis of the circle fitting. The pretreatment is used by circle fitting, and the improved adaptive denoising filter for TV repair technology can effectively improves the accuracy of the spot center position. At the same time, the pretreatment and de-noising can effectively reduce the influence of Gaussian white noise, which enhances the anti-jamming capability.

Analysis of alkyl phosphates in petroleum samples by comprehensive two-dimensional gas chromatography with nitrogen phosphorus detection and post-column Deans switching.

PubMed

Nizio, Katie D; Harynuk, James J

2012-08-24

Alkyl phosphate based gellants used as viscosity builders for fracturing fluids used in the process of hydraulic fracturing have been implicated in numerous refinery-fouling incidents in North America. In response, industry developed an inductively coupled plasma optical emission spectroscopy (ICP-OES) based method for the analysis of total volatile phosphorus in distillate fractions of crude oil; however, this method is plagued by poor precision and a high limit of detection (0.5±1μg phosphorus mL(-1)). Furthermore this method cannot provide speciation information, which is critical for developing an understanding of the challenge of alkyl phosphates at a molecular level. An approach using comprehensive two-dimensional gas chromatography with nitrogen phosphorus detection (GC×GC-NPD) and post-column Deans switching is presented. This method provides qualitative and quantitative profiles of alkyl phosphates in industrial petroleum samples with increased precision and at levels comparable to or below those achievable by ICP-OES. A recovery study in a fracturing fluid sample and a profiling study of alkyl phosphates in four recovered fracturing fluid/crude oil mixtures (flowback) are also presented. Copyright © 2012 Elsevier B.V. All rights reserved.

Precise measurement of ultra-narrow laser linewidths using the strong coherent envelope

NASA Astrophysics Data System (ADS)

Huang, Shihong; Zhu, Tao; Liu, Min; Huang, Wei

2017-02-01

Laser linewidth narrowing down to kHz or even Hz is an important topic in areas like clock synchronization technology, laser radars, quantum optics, and high-precision detection. Conventional decoherence measurement methods like delayed self-heterodyne/homodyne interferometry cannot measure such narrow linewidths accurately. This is because a broadening of the Gaussian spectrum, which hides the laser’s intrinsic Lorentzian linewidth, cannot be avoided. Here, we introduce a new method using the strong coherent envelope to characterize the laser’s intrinsic linewidth through self-coherent detection. This method can eliminate the effect of the broadened Gaussian spectrum induced by the 1/f frequency noise. We analyze, in detail, the relationship between intrinsic laser linewidth, contrast difference with the second peak and the second trough (CDSPST) of the strong coherent envelope, and the length of the delaying fiber. The correct length for the delaying fiber can be chosen by combining the estimated laser linewidth (Δfest) with a specific CDSPST (ΔS) to obtain the accurate laser linewidth (Δf). Our results indicate that this method can be used as an accurate detection tool for measurements of narrow or super-narrow linewidths.

Muons and neutrinos

NASA Technical Reports Server (NTRS)

Stanev, T.

1986-01-01

The first generation of large and precise detectors, some initially dedicated to search for nucleon decay has accumulated significant statistics on neutrinos and high-energy muons. A second generation of even better and bigger detectors are already in operation or in advanced construction stage. The present set of experimental data on muon groups and neutrinos is qualitatively better than several years ago and the expectations for the following years are high. Composition studies with underground muon groups, neutrino detection, and expected extraterrestrial neutrino fluxes are discussed.

Speciation of chromium using reversed phase-high performance liquid chromatography coupled to different spectrometric detection methods

NASA Astrophysics Data System (ADS)

Andrle, C. M.; Jakubowski, N.; Broekaert, J. A. C.

1997-02-01

Speciation of Cr(III) and Cr(VI) based on the formation of different complexes with ammonium-pyrrolidinedithioate (APDC) in a continuous flow technique and their preconcentration using solid phase extraction (SPE) have been elaborated and applied to the analysis of waste waters from the galvanic industry. The Cr complexes were separated and determined using reversed phase-high performance liquid chromatography (RP-HPLC) coupled to different detection methods, namely UV-detection, graphite furnace-atomic absorption spectrometry (GF-AAS) and inductively coupled plasma mass spectrometry with hydraulic high pressure nebulization (HHPN/ICP-MS). After optimization the detection limits for Cr(III) and Cr(VI) of all methods are at the μg 1 -1 level and the precision in terms of RSD is 5% ( cCr = 100 μg 1 -1, N = 10). The procedure was applied to the determination of Cr(III) and Cr(VI) at the μg 1 -1 level in galvanic waste waters, and its accuracy was approved by comparing the results with those of independent methods.

High-order optical vortex position detection using a Shack-Hartmann wavefront sensor.

PubMed

Luo, Jia; Huang, Hongxin; Matsui, Yoshinori; Toyoda, Haruyoshi; Inoue, Takashi; Bai, Jian

2015-04-06

Optical vortex (OV) beams have null-intensity singular points, and the intensities in the region surrounding the singular point are quite low. This low intensity region influences the position detection accuracy of phase singular point, especially for high-order OV beam. In this paper, we propose a new method for solving this problem, called the phase-slope-combining correlation matching method. A Shack-Hartmann wavefront sensor (SH-WFS) is used to measure phase slope vectors at lenslet positions of the SH-WFS. Several phase slope vectors are combined into one to reduce the influence of low-intensity regions around the singular point, and the combined phase slope vectors are used to determine the OV position with the aid of correlation matching with a pre-calculated database. Experimental results showed that the proposed method works with high accuracy, even when detecting an OV beam with a topological charge larger than six. The estimated precision was about 0.15 in units of lenslet size when detecting an OV beam with a topological charge of up to 20.

Development of a 2-micron Pulsed Direct Detection IPDA Lidar for CO2 Measurement

NASA Astrophysics Data System (ADS)

Yu, J.; Petros, M.; Singh, U. N.

2013-12-01

NASA Langley is developing a 2-micron pulsed Integrated Path Differential Absorption (IPDA) lidar for atmospheric CO2 measurements. The high pulse energy, direct detection lidar operating at CO2 2-micron absorption band provides an alternate approach to measure CO2 concentrations with significant advantages. The objective of this development is to integrate an existing high energy double-pulsed 2-micron laser transmitter with a direct detection receiver and telescope to enable a first proof of principle demonstration of airborne direct detection CO2 measurements at 2-micron wavelength. It is expected to provide high-precision measurement capability by unambiguously eliminating contamination from aerosols and clouds that can bias the IPDA measurement. The system is scheduled to fly on NASA UC12 or B200 research aircrafts before the end of 2013. This paper will describe the design of the airborne 2-micron pulsed IPDA lidar system; the lidar operation parameters; the wavelength pair selection; laser transmitter energy, pulse rate, beam divergence, double pulse generation and accurate frequency control; detector characterization; telescope design; lidar structure design; and lidar signal to noise ratio estimation.

Electromagnetic tracking (EMT) technology for improved treatment quality assurance in interstitial brachytherapy.

PubMed

Kellermeier, Markus; Herbolzheimer, Jens; Kreppner, Stephan; Lotter, Michael; Strnad, Vratislav; Bert, Christoph

2017-01-01

Electromagnetic Tracking (EMT) is a novel technique for error detection and quality assurance (QA) in interstitial high dose rate brachytherapy (HDR-iBT). The purpose of this study is to provide a concept for data acquisition developed as part of a clinical evaluation study on the use of EMT during interstitial treatment of breast cancer patients. The stability, accuracy, and precision of EMT-determined dwell positions were quantified. Dwell position reconstruction based on EMT was investigated on CT table, HDR table and PDR bed to examine the influence on precision and accuracy in a typical clinical workflow. All investigations were performed using a precise PMMA phantom. The track of catheters inserted in that phantom was measured by manually inserting a 5 degree of freedom (DoF) sensor while recording the position of three 6DoF fiducial sensors on the phantom surface to correct motion influences. From the corrected data, dwell positions were reconstructed along the catheter's track. The accuracy of the EMT-determined dwell positions was quantified by the residual distances to reference dwell positions after using a rigid registration. Precision and accuracy were investigated for different phantom-table and sensor-field generator (FG) distances. The measured precision of the EMT-determined dwell positions was ≤ 0.28 mm (95th percentile). Stability tests showed a drift of 0.03 mm in the first 20 min of use. Sudden shaking of the FG or (large) metallic objects close to the FG degrade the precision. The accuracy with respect to the reference dwell positions was on all clinical tables < 1 mm at 200 mm FG distance and 120 mm phantom-table distance. Phantom measurements showed that EMT-determined localization of dwell positions in HDR-iBT is stable, precise, and sufficiently accurate for clinical assessment. The presented method may be viable for clinical applications in HDR-iBT, like implant definition, error detection or quantification of uncertainties. Further clinical investigations are needed. © 2017 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

Detection of active transposable elements in Arabidopsis thaliana using Oxford Nanopore Sequencing technology.

PubMed

Debladis, Emilie; Llauro, Christel; Carpentier, Marie-Christine; Mirouze, Marie; Panaud, Olivier

2017-07-17

Transposables elements (TEs) contribute to both structural and functional dynamics of most eukaryotic genomes. Because of their propensity to densely populate plant and animal genomes, the precise estimation of the impact of transposition on genomic diversity has been considered as one of the main challenges of today's genomics. The recent development of NGS (next generation sequencing) technologies has open new perspectives in population genomics by providing new methods for high throughput detection of Transposable Elements-associated Structural Variants (TEASV). However, these have relied on Illumina platform that generates short reads (up to 350 nucleotides). This limitation in size of sequence reads can cause high false discovery rate (FDR) and therefore limit the power of detection of TEASVs, especially in the case of large, complex genomes. The newest sequencing technologies, such as Oxford Nanopore Technologies (ONT) can generate kilobases-long reads thus representing a promising tool for TEASV detection in plant and animals. We present the results of a pilot experiment for TEASV detection on the model plant species Arabidopsis thaliana using ONT sequencing and show that it can be used efficiently to detect TE movements. We generated a ~0.8X genome coverage of a met1-derived epigenetic recombinant inbred line (epiRIL) using a MinIon device with R7 chemistry. We were able to detect nine new copies of the LTR-retrotransposon Evadé (EVD). We also evidenced the activity of the DNA transposon CACTA, CAC1. Even at a low sequence coverage (0.8X), ONT sequencing allowed us to reliably detect several TE insertions in Arabidopsis thaliana genome. The long read length allowed a precise and un-ambiguous mapping of the structural variations caused by the activity of TEs. This suggests that the trade-off between read length and genome coverage for TEASV detection may be in favor of the former. Should the technology be further improved both in terms of lower error rate and operation costs, it could be efficiently used in diversity studies at population level.

Development and Validation of Liquid Chromatographic Method for Estimation of Naringin in Nanoformulation

PubMed Central

Musmade, Kranti P.; Trilok, M.; Dengale, Swapnil J.; Bhat, Krishnamurthy; Reddy, M. S.; Musmade, Prashant B.; Udupa, N.

2014-01-01

A simple, precise, accurate, rapid, and sensitive reverse phase high performance liquid chromatography (RP-HPLC) method with UV detection has been developed and validated for quantification of naringin (NAR) in novel pharmaceutical formulation. NAR is a polyphenolic flavonoid present in most of the citrus plants having variety of pharmacological activities. Method optimization was carried out by considering the various parameters such as effect of pH and column. The analyte was separated by employing a C18 (250.0 × 4.6 mm, 5 μm) column at ambient temperature in isocratic conditions using phosphate buffer pH 3.5: acetonitrile (75 : 25% v/v) as mobile phase pumped at a flow rate of 1.0 mL/min. UV detection was carried out at 282 nm. The developed method was validated according to ICH guidelines Q2(R1). The method was found to be precise and accurate on statistical evaluation with a linearity range of 0.1 to 20.0 μg/mL for NAR. The intra- and interday precision studies showed good reproducibility with coefficients of variation (CV) less than 1.0%. The mean recovery of NAR was found to be 99.33 ± 0.16%. The proposed method was found to be highly accurate, sensitive, and robust. The proposed liquid chromatographic method was successfully employed for the routine analysis of said compound in developed novel nanopharmaceuticals. The presence of excipients did not show any interference on the determination of NAR, indicating method specificity. PMID:26556205

A cloud shadow detection method combined with cloud height iteration and spectral analysis for Landsat 8 OLI data

NASA Astrophysics Data System (ADS)

Sun, Lin; Liu, Xinyan; Yang, Yikun; Chen, TingTing; Wang, Quan; Zhou, Xueying

2018-04-01

Although enhanced over prior Landsat instruments, Landsat 8 OLI can obtain very high cloud detection precisions, but for the detection of cloud shadows, it still faces great challenges. Geometry-based cloud shadow detection methods are considered the most effective and are being improved constantly. The Function of Mask (Fmask) cloud shadow detection method is one of the most representative geometry-based methods that has been used for cloud shadow detection with Landsat 8 OLI. However, the Fmask method estimates cloud height employing fixed temperature rates, which are highly uncertain, and errors of large area cloud shadow detection can be caused by errors in estimations of cloud height. This article improves the geometry-based cloud shadow detection method for Landsat OLI from the following two aspects. (1) Cloud height no longer depends on the brightness temperature of the thermal infrared band but uses a possible dynamic range from 200 m to 12,000 m. In this case, cloud shadow is not a specific location but a possible range. Further analysis was carried out in the possible range based on the spectrum to determine cloud shadow location. This effectively avoids the cloud shadow leakage caused by the error in the height determination of a cloud. (2) Object-based and pixel spectral analyses are combined to detect cloud shadows, which can realize cloud shadow detection from two aspects of target scale and pixel scale. Based on the analysis of the spectral differences between the cloud shadow and typical ground objects, the best cloud shadow detection bands of Landsat 8 OLI were determined. The combined use of spectrum and shape can effectively improve the detection precision of cloud shadows produced by thin clouds. Several cloud shadow detection experiments were carried out, and the results were verified by the results of artificial recognition. The results of these experiments indicated that this method can identify cloud shadows in different regions with correct accuracy exceeding 80%, approximately 5% of the areas were wrongly identified, and approximately 10% of the cloud shadow areas were missing. The accuracy of this method is obviously higher than the recognition accuracy of Fmask, which has correct accuracy lower than 60%, and the missing recognition is approximately 40%.

Detection of magnetic fields in chemically peculiar stars observed with the K2 space mission

NASA Astrophysics Data System (ADS)

Buysschaert, B.; Neiner, C.; Martin, A. J.; Aerts, C.; Bowman, D. M.; Oksala, M. E.; Van Reeth, T.

2018-05-01

We report the results of an observational study aimed at searching for magnetic pulsating hot stars suitable for magneto-asteroseismology. A sample of sixteen chemically peculiar stars was selected and analysed using both high-resolution spectropolarimetry with ESPaDOnS and K2 high-precision space photometry. For all stars, we derive the effective temperature, surface gravity, rotational and non-rotational line broadening from our spectropolarimetric data. High-quality K2 light curves were obtained for thirteen of the sixteen stars and revealed rotational modulation, providing accurate rotation periods. Two stars show evidence for roAp pulsations, and one star shows signatures of internal gravity waves or unresolved g-mode pulsations. We confirm the presence of a large-scale magnetic field for eleven of the studied stars, of which nine are first detections. Further, we report one marginal detection and four non-detections. Two of the stars with a non-detected magnetic field show rotational modulation due to surface abundance inhomogeneities in the K2 light curve, and we confirm that the other two are chemically peculiar. Thus, these five stars likely host a weak (undetected) large-scale magnetic field.

HAI: A novel airborne multi-channel hygrometer for fast multi-phase H2O quantification: Performance of the HAI instrument during the first flights on the German HALO aircraft

NASA Astrophysics Data System (ADS)

Buchholz, B.; Ebert, V.; Kraemer, M.; Afchine, A.

2014-12-01

Common gas phase H2O measurements on fast airborne platforms e.g. using backward facing or "Rosemount"-inlets can lead to a high risk of ice and droplets contamination. In addition, currently no single hygrometer exists that allows a simultaneous, high-speed measurement of all phases (gas, liquid, ice) with the same detection principle. In the rare occasions multi-phase measurements are realized, gas-and condensed-phase observations rely on different methods, instruments and calibration strategies so that precision and accuracy levels are quite difficult to quantify. This is effectively avoided by the novel TDLAS instrument, HAI, Hygrometer for Atmospheric Investigation, which allows a simultaneous, high speed, multi-phase detection without any sensor calibration in a unique "2+2" channel concept. Hai combines two independent wavelength channels, at 1.4 µm and at 2.6 µm, for a wide dynamic range from 1 to 30 000 ppmv, with a simultaneous closed path (extractive) and open path detection. Thus, "Total", i.e. gas-phase plus condensed-phase water is measured by sampling via a forward facing inlet into "closed-path" extractive cells. A selective, sampling-free, high speed gas phase detection is realized via a dual-wavelength "open-path" cell placed outside of the aircraft fuselage. All channels can be sampled with 120 Hz (measurement cycle time Dt=1.6 ms) allowing an unprecedented spatial resolution of 30 cm at 900 km/h. The evaluation of the individual multi-channel raw-data is done post flight, without any channel interdependencies, in calibration-free mode, thus allowing fast, accurate and precise multi-phase water detection in flight. The performance could be shown in more than 200 net flights hours in three scientific flight campaigns (TACTS, ESMVal, ML-CIRRUS) on the new German HALO aircraft. In addition the level of the accuracy of the calibration free evaluation was evaluated at the German national primary water vapor standard.

Characterizing viscoelastic mechanical properties of highly compliant polymers and biological tissues using impact indentation.

PubMed

Mijailovic, Aleksandar S; Qing, Bo; Fortunato, Daniel; Van Vliet, Krystyn J

2018-04-15

Precise and accurate measurement of viscoelastic mechanical properties becomes increasingly challenging as sample stiffness decreases to elastic moduli <1 kPa, largely due to difficulties detecting initial contact with the compliant sample surface. This limitation is particularly relevant to characterization of biological soft tissues and compliant gels. Here, we employ impact indentation which, in contrast to shear rheology and conventional indentation, does not require contact detection a priori, and present a novel method to extract viscoelastic moduli and relaxation time constants directly from the impact response. We first validate our approach by using both impact indentation and shear rheology to characterize polydimethylsiloxane (PDMS) elastomers of stiffness ranging from 100 s of Pa to nearly 10 kPa. Assuming a linear viscoelastic constitutive model for the material, we find that the moduli and relaxation times obtained from fitting the impact response agree well with those obtained from fitting the rheological response. Next, we demonstrate our validated method on hydrated, biological soft tissues obtained from porcine brain, murine liver, and murine heart, and report the equilibrium shear moduli, instantaneous shear moduli, and relaxation time constants for each tissue. Together, our findings provide a new and straightforward approach capable of probing local mechanical properties of highly compliant viscoelastic materials with millimeter scale spatial resolution, mitigating complications involving contact detection or sample geometric constraints. Characterization and optimization of mechanical properties can be essential for the proper function of biomaterials in diverse applications. However, precise and accurate measurement of viscoelastic mechanical properties becomes increasingly difficult with increased compliance (particularly for elastic moduli <1 kPa), largely due to challenges detecting initial contact with the compliant sample surface and measuring response at short timescale or high frequency. By contrast, impact indentation has highly accurate contact detection and can be used to measure short timescale (glassy) response. Here, we demonstrate an experimental and analytical method that confers significant advantages over existing approaches to extract spatially resolved viscoelastic moduli and characteristic time constants of biological tissues (e.g., brain and heart) and engineered biomaterials. Copyright © 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

An Image-Based Algorithm for Precise and Accurate High Throughput Assessment of Drug Activity against the Human Parasite Trypanosoma cruzi

PubMed Central

Moraes, Carolina Borsoi; Yang, Gyongseon; Kang, Myungjoo; Freitas-Junior, Lucio H.; Hansen, Michael A. E.

2014-01-01

We present a customized high content (image-based) and high throughput screening algorithm for the quantification of Trypanosoma cruzi infection in host cells. Based solely on DNA staining and single-channel images, the algorithm precisely segments and identifies the nuclei and cytoplasm of mammalian host cells as well as the intracellular parasites infecting the cells. The algorithm outputs statistical parameters including the total number of cells, number of infected cells and the total number of parasites per image, the average number of parasites per infected cell, and the infection ratio (defined as the number of infected cells divided by the total number of cells). Accurate and precise estimation of these parameters allow for both quantification of compound activity against parasites, as well as the compound cytotoxicity, thus eliminating the need for an additional toxicity-assay, hereby reducing screening costs significantly. We validate the performance of the algorithm using two known drugs against T.cruzi: Benznidazole and Nifurtimox. Also, we have checked the performance of the cell detection with manual inspection of the images. Finally, from the titration of the two compounds, we confirm that the algorithm provides the expected half maximal effective concentration (EC50) of the anti-T. cruzi activity. PMID:24503652

Detection system for neutron β decay correlations in the UCNB and Nab experiments

DOE PAGES

Broussard, L. J.; Oak Ridge National Lab.; Zeck, B. A.; ...

2016-12-19

Here, we describe a detection system designed to precisely measure multiple correlations in neutron β decay. Furthermore, the system is based on thick, large area, highly segmented silicon detectors developed in collaboration with Micron Semiconductor, Ltd. The prototype system meets specifications of energy thresholds below 10 keV, energy resolution of ~3 keV FWHM, and rise time of ~50 ns with 19 of the 127 detector pixels instrumented. We have demonstrated the coincident detection of β particles and recoil protons from neutron β decay, using ultracold neutrons at the Los Alamos Neutron Science Center, . The fully instrumented detection system willmore » be implemented in the UCNB and Nab experiments, to determine the neutron β decay parameters B, a, and b.« less

A Self Contained Method for Safe and Precise Lunar Landing

NASA Technical Reports Server (NTRS)

Paschall, Stephen C., II; Brady, Tye; Cohanim, Babak; Sostaric, Ronald

2008-01-01

The return of humans to the Moon will require increased capability beyond that of the previous Apollo missions. Longer stay times and a greater flexibility with regards to landing locations are among the many improvements planned. A descent and landing system that can land the vehicle more accurately than Apollo with a greater ability to detect and avoid hazards is essential to the development of a Lunar Outpost, and also for increasing the number of potentially reachable Lunar Sortie locations. This descent and landing system should allow landings in more challenging terrain and provide more flexibility with regards to mission timing and lighting considerations, while maintaining safety as the top priority. The lunar landing system under development by the ALHAT (Autonomous precision Landing and Hazard detection Avoidance Technology) project is addressing this by providing terrain-relative navigation measurements to enhance global-scale precision, an onboard hazard-detection system to select safe landing locations, and an Autonomous GNC (Guidance, Navigation, and Control) capability to process these measurements and safely direct the vehicle to this landing location. This ALHAT landing system will enable safe and precise lunar landings without requiring lunar infrastructure in the form of navigation aids or a priori identified hazard-free landing locations. The safe landing capability provided by ALHAT uses onboard active sensing to detect hazards that are large enough to be a danger to the vehicle but too small to be detected from orbit, given currently planned orbital terrain resolution limits. Algorithms to interpret raw active sensor terrain data and generate hazard maps as well as identify safe sites and recalculate new trajectories to those sites are included as part of the ALHAT System. These improvements to descent and landing will help contribute to repeated safe and precise landings for a wide variety of terrain on the Moon.

Demonstration of Helicopter Multi-Towed Array Detection System (MTADS) Magnetometry Technology at Pueblo Precision Bombing Range #2, Colorado

DTIC Science & Technology

2008-08-28

for aircraft pitch measurement Fluxgate magnetometer 10 RS232- ASCII SerialDevice.fluxgate Provides redundant aircraft attitude measurement...Figure 28. Filtered, ’final’ magnetometer data taken at high altitude. ......................................................... 43 LIST OF TABLES...flight. The magnetometer data can be analyzed to extract either distributions of magnetic anomalies (which can be further used to locate and bound

Security Engineering Pilot

DTIC Science & Technology

2013-02-28

needed to detect and isolate the compromised component • Prevent a cyber attack exploit from reading enough information to form a coherent data set...Analysis Signal Copy Selected Sub-Bands • Gimbaled, Stabilized EO/IR Camera Ball • High Precision GPS & INS (eventual swarm capable inter-UAV coherent ... LIDAR , HSI, Chem-Bio • Multi-Platform Distributed Sensor Experiments (eg, MIMO) • Autonomous & Collaborative Multi-Platform Control • Space for

Challenges to estimating tree height via LiDAR in closed-canopy forest: a parable from western Oregon

Treesearch

Demetrios Gatziolis; Jeremy S. Fried; Vicente S. Monleon

2010-01-01

We examine the accuracy of tree height estimates obtained via light detection and ranging (LiDAR) in a temperate rainforest characterized by complex terrain, steep slopes, and high canopy cover. The evaluation was based on precise top and base locations for > 1,000 trees in 45 plots distributed across three forest types, a dense network of ground elevation...

Precision Seismic Monitoring of Volcanic Eruptions at Axial Seamount

NASA Astrophysics Data System (ADS)

Waldhauser, F.; Wilcock, W. S. D.; Tolstoy, M.; Baillard, C.; Tan, Y. J.; Schaff, D. P.

2017-12-01

Seven permanent ocean bottom seismometers of the Ocean Observatories Initiative's real time cabled observatory at Axial Seamount off the coast of the western United States record seismic activity since 2014. The array captured the April 2015 eruption, shedding light on the detailed structure and dynamics of the volcano and the Juan de Fuca midocean ridge system (Wilcock et al., 2016). After a period of continuously increasing seismic activity primarily associated with the reactivation of caldera ring faults, and the subsequent seismic crisis on April 24, 2015 with 7000 recorded events that day, seismicity rates steadily declined and the array currently records an average of 5 events per day. Here we present results from ongoing efforts to automatically detect and precisely locate seismic events at Axial in real-time, providing the computational framework and fundamental data that will allow rapid characterization and analysis of spatio-temporal changes in seismogenic properties. We combine a kurtosis-based P- and S-phase onset picker and time domain cross-correlation detection and phase delay timing algorithms together with single-event and double-difference location methods to rapidly and precisely (tens of meters) compute the location and magnitudes of new events with respect to a 2-year long, high-resolution background catalog that includes nearly 100,000 events within a 5×5 km region. We extend the real-time double-difference location software DD-RT to efficiently handle the anticipated high-rate and high-density earthquake activity during future eruptions. The modular monitoring framework will allow real-time tracking of other seismic events such as tremors and sea-floor lava explosions that enable the timing and location of lava flows and thus guide response research cruises to the most interesting sites. Finally, rapid detection of eruption precursors and initiation will allow for adaptive sampling by the OOI instruments for optimal recording of future eruptions. With a higher eruption recurrence rate than land-based volcanoes the Axial OOI observatory offers the opportunity to monitor and study volcanic eruptions throughout multiple cycles.

Analytical Method Development and Validation for the Simultaneous Estimation of Abacavir and Lamivudine by Reversed-phase High-performance Liquid Chromatography in Bulk and Tablet Dosage Forms.

PubMed

Raees Ahmad, Sufiyan Ahmad; Patil, Lalit; Mohammed Usman, Mohammed Rageeb; Imran, Mohammad; Akhtar, Rashid

2018-01-01

A simple rapid, accurate, precise, and reproducible validated reverse phase high performance liquid chromatography (HPLC) method was developed for the determination of Abacavir (ABAC) and Lamivudine (LAMI) in bulk and tablet dosage forms. The quantification was carried out using Symmetry Premsil C18 (250 mm × 4.6 mm, 5 μm) column run in isocratic way using mobile phase comprising methanol: water (0.05% orthophosphoric acid with pH 3) 83:17 v/v and a detection wavelength of 245 nm and injection volume of 20 μl, with a flow rate of 1 ml/min. In the developed method, the retention times of ABAC and LAMI were found to be 3.5 min and 7.4 min, respectively. The method was validated in terms of linearity, precision, accuracy, limits of detection, limits of quantitation, and robustness in accordance with the International Conference on Harmonization guidelines. The assay of the proposed method was found to be 99% - 101%. The recovery studies were also carried out and mean % recovery was found to be 99% - 101%. The % relative standard deviation from reproducibility was found to be <2%. The proposed method was statistically evaluated and can be applied for routine quality control analysis of ABAC and LAMI in bulk and in tablet dosage form. Attempts were made to develop RP-HPLC method for simultaneous estimation of Abacavir and Lamivudine for the RP-HPLC method. The developed method was validated according to the ICH guidelines. The linearity, precision, range, robustness were within the limits as specified by the ICH guidelines. Hence the method was found to be simple, accurate, precise, economic and reproducible. So the proposed methods can be used for the routine quality control analysis of Abacavir and Lamivudine in bulk drug as well as in formulations. Abbreviations Used: HPLC: High-performance liquid chromatography, UV: Ultraviolet, ICH: International Conference on Harmonization, ABAC: Abacavir, LAMI: Lamivudine, HIV: Human immunodeficiency virus, AIDS: Acquired immunodeficiency syndrome, NRTI: Nucleoside reverse transcriptase inhibitors, ARV: Antiretroviral, RSD: Relative standard deviation, RT: Retention time, SD: Standard deviation.

Neutron activation analyses and half-life measurements at the usgs triga reactor

NASA Astrophysics Data System (ADS)

Larson, Robert E.

Neutron activation of materials followed by gamma spectroscopy using high-purity germanium detectors is an effective method for making measurements of nuclear beta decay half-lives and for detecting trace amounts of elements present in materials. This research explores applications of neutron activation analysis (NAA) in two parts. Part 1. High Precision Methods for Measuring Decay Half-Lives, Chapters 1 through 8 Part one develops research methods and data analysis techniques for making high precision measurements of nuclear beta decay half-lives. The change in the electron capture half-life of 51Cr in pure chromium versus chromium mixed in a gold lattice structure is explored, and the 97Ru electron capture decay half-life are compared for ruthenium in a pure crystal versus ruthenium in a rutile oxide state, RuO2. In addition, the beta-minus decay half-life of 71mZn is measured and compared with new high precision findings. Density Functional Theory is used to explain the measured magnitude of changes in electron capture half-life from changes in the surrounding lattice electron configuration. Part 2. Debris Collection Nuclear Diagnostic at the National Ignition Facility, Chapters 9 through 11 Part two explores the design and development of a solid debris collector for use as a diagnostic tool at the National Ignition Facility (NIF). NAA measurements are performed on NIF post-shot debris collected on witness plates in the NIF chamber. In this application NAA is used to detect and quantify the amount of trace amounts of gold from the hohlraum and germanium from the pellet present in the debris collected after a NIF shot. The design of a solid debris collector based on material x-ray ablation properties is given, and calculations are done to predict performance and results for the collection and measurements of trace amounts of gold and germanium from dissociated hohlraum debris.

MONDO: A neutron tracker for particle therapy secondary emission fluxes measurements

NASA Astrophysics Data System (ADS)

Marafini, M.; Patera, V.; Pinci, D.; Sarti, A.; Sciubba, A.; Spiriti, E.

2016-07-01

Cancer treatment is performed, in Particle Therapy, using accelerated charged particles whose high irradiation precision and conformity allows the tumor destruction while sparing the surrounding healthy tissues. Dose release monitoring devices using photons and charged particles produced by the beam interaction with the patient body have already been proposed, but no attempt based on the detection of the abundant secondary radiation neutron component has been made yet. The reduced attenuation length of neutrons yields a secondary particle sample that is larger in number when compared to photons and charged particles. Furthermore, neutrons allow for a backtracking of the emission point that is not affected by multiple scattering. Since neutrons can release a significant dose far away from the tumor region, a precise measurement of their flux, production energy and angle distributions is eagerly needed in order to improve the Treatment Planning Systems (TPS) software, so to predict not only the normal tissue toxicity in the target region but also the risk of late complications in the whole body. All the aforementioned issues underline the importance for an experimental effort devoted to the precise characterization of the neutron production gaining experimental access both to the emission point and production energy. The technical challenges posed by a neutron detector aiming for a high detection efficiency and good backtracking precision will be addressed within the MONDO (MOnitor for Neutron Dose in hadrOntherapy) project. The MONDO's main goal is to develop a tracking detector targeting fast and ultrafast secondary neutrons. The tracker is composed by a scintillating fiber matrix (4 × 4 × 8cm3). The full reconstruction of protons, produced in elastic interactions, will be used to measure energy and direction of the impinging neutron. The neutron tracker will measure the neutron production yields, as a function of production angle and energy, using different therapeutic beams at CNAO in Pavia (protons, 12C ions and possibly 4He and 16O ions).

Exposure to 4,4'-methylenediphenyl diisocyanate (MDI) during moulding of rigid polyurethane foam: determination of airborne MDI and urinary 4,4'-methylenedianiline (MDA).

PubMed

Kääriä, K; Hirvonen, A; Norppa, H; Piirilä, P; Vainio, H; Rosenberg, C

2001-04-01

Occupational exposure to 4,4'-methylenediphenyl diisocyanate (MDI) was measured during moulding of rigid polyurethane foam. The aim of the study was to find out whether an MDI-derived urinary amine metabolite could be detected in the urine of workers exposed to apparently low levels of MDI. Airborne MDI was sampled on 1-(2-methoxyphenyl)-piperazine (2MP)-impregnated glass fibre filters and determined by high-performance liquid chromatography (HPLC) using ultraviolet (UV) and electrochemical (EC) detection. The limit of detection of MDI was 3 ng ml-1 for a 20 microliters injection. The precision of sample preparation, expressed as relative standard deviation (RSD), was 1.3% with UV detection and 2.1% with EC detection at a concentration of 70 ng MDI ml-1 (n = 6). The 2MP-MDI derivative was stable at +4 degrees C up to eight weeks. The accuracy of the method was validated in an international quality control programme. Workers (n = 57) from three different factories participated in the study. Urinary 4,4'-methylenedianiline (MDA) metabolite was determined after acid hydrolysis as heptafluorobutyric anhydride derivatives by gas chromatography-mass spectrometry using chemical ionisation and monitoring negative ions. The limit of detection in urine was 0.2 nmol l-1. The precision of six analyses for a urine sample spiked to a concentration of 1 nmol l-1 was 29% (RSD). The MDI concentrations were below the limit of detection in most (64%) of the air samples collected in the worker's breathing zone. Still, detectable amounts of MDA were found in 97% of the urine samples. Monitoring of urinary MDA appears to be an appropriate method of assessing MDI exposure in work environments with low or undetectable MDI concentrations in the workplace air.

Detection of grapes in natural environment using HOG features in low resolution images

NASA Astrophysics Data System (ADS)

Škrabánek, Pavel; Majerík, Filip

2017-07-01

Detection of grapes in real-life images has importance in various viticulture applications. A grape detector based on an SVM classifier, in combination with a HOG descriptor, has proven to be very efficient in detection of white varieties in high-resolution images. Nevertheless, the high time complexity of such utilization was not suitable for its real-time applications, even when a detector of a simplified structure was used. Thus, we examined possibilities of the simplified version application on images of lower resolutions. For this purpose, we designed a method aimed at search for a detector’s setting which gives the best time complexity vs. performance ratio. In order to provide precise evaluation results, we formed new extended datasets. We discovered that even applied on low-resolution images, the simplified detector, with an appropriate setting of all tuneable parameters, was competitive with other state of the art solutions. We concluded that the detector is qualified for real-time detection of grapes in real-life images.

Sensitive spin detection using an on-chip SQUID-waveguide resonator

NASA Astrophysics Data System (ADS)

Yue, G.; Chen, L.; Barreda, J.; Bevara, V.; Hu, L.; Wu, L.; Wang, Z.; Andrei, P.; Bertaina, S.; Chiorescu, I.

2017-11-01

Precise detection of spin resonance is of paramount importance to achieve coherent spin control in quantum computing. We present a setup for spin resonance measurements, which uses a dc-SQUID flux detector coupled to an antenna from a coplanar waveguide. The SQUID and the waveguide are fabricated from a 20 nm Nb thin film, allowing high magnetic field operation with the field applied parallel to the chip. We observe a resonance signal between the first and third excited states of Gd spins S = 7/2 in a CaWO4 crystal, relevant for state control in multi-level systems.

Wide-Field Imaging Using Nitrogen Vacancies

NASA Technical Reports Server (NTRS)

Englund, Dirk Robert (Inventor); Trusheim, Matthew Edwin (Inventor)

2017-01-01

Nitrogen vacancies in bulk diamonds and nanodiamonds can be used to sense temperature, pressure, electromagnetic fields, and pH. Unfortunately, conventional sensing techniques use gated detection and confocal imaging, limiting the measurement sensitivity and precluding wide-field imaging. Conversely, the present sensing techniques do not require gated detection or confocal imaging and can therefore be used to image temperature, pressure, electromagnetic fields, and pH over wide fields of view. In some cases, wide-field imaging supports spatial localization of the NVs to precisions at or below the diffraction limit. Moreover, the measurement range can extend over extremely wide dynamic range at very high sensitivity.

Transdermal Diagnosis of Malaria Using Vapor Nanobubbles.

PubMed

Lukianova-Hleb, Ekaterina; Bezek, Sarah; Szigeti, Reka; Khodarev, Alexander; Kelley, Thomas; Hurrell, Andrew; Berba, Michail; Kumar, Nirbhay; D'Alessandro, Umberto; Lapotko, Dmitri

2015-07-01

A fast, precise, noninvasive, high-throughput, and simple approach for detecting malaria in humans and mosquitoes is not possible with current techniques that depend on blood sampling, reagents, facilities, tedious procedures, and trained personnel. We designed a device for rapid (20-second) noninvasive diagnosis of Plasmodium falciparum infection in a malaria patient without drawing blood or using any reagent. This method uses transdermal optical excitation and acoustic detection of vapor nanobubbles around intraparasite hemozoin. The same device also identified individual malaria parasite-infected Anopheles mosquitoes in a few seconds and can be realized as a low-cost universal tool for clinical and field diagnoses.

A challenging issue: Detection of white matter hyperintensities in neonatal brain MRI.

PubMed

Morel, Baptiste; Yongchao Xu; Virzi, Alessio; Geraud, Thierry; Adamsbaum, Catherine; Bloch, Isabelle

2016-08-01

The progress of magnetic resonance imaging (MRI) allows for a precise exploration of the brain of premature infants at term equivalent age. The so-called DEHSI (diffuse excessive high signal intensity) of the white matter of premature brains remains a challenging issue in terms of definition, and thus of interpretation. We propose a semi-automatic detection and quantification method of white matter hyperintensities in MRI relying on morphological operators and max-tree representations, which constitutes a powerful tool to help radiologists to improve their interpretation. Results show better reproducibility and robustness than interactive segmentation.

Deproteinizing methods evaluated for determination of uric acid in serum by reversed-phase liquid chromatography with ultraviolet detection.

PubMed

Sakuma, R; Nishina, T; Kitamura, M

1987-08-01

We evaluated six deproteinizing methods for determination of uric acid in serum by "high-performance" liquid chromatography with ultraviolet detection: those involving zinc hydroxide, sodium tungstate, trichloroacetic acid, perchloric acid, acetonitrile, and centrifugal ultrafiltration (with Amicon MPS-1 devices). We used a Toyosoda ODS-120A reversed-phase column. The mobile phase was sodium phosphate buffer (40 mmol/L, pH 2.2) containing 20 mL of methanol per liter. Absorbance of the eluate was monitored at 284 nm. The precipitation method with perchloric acid gave high recoveries of uric acid and good precision, and results agreed with those by the uricase-catalase method of Kageyama (Clin Chim Acta 1971;31:421-6).

Selective attention within the foveola.

PubMed

Poletti, Martina; Rucci, Michele; Carrasco, Marisa

2017-10-01

Efficient control of attentional resources and high-acuity vision are both fundamental for survival. Shifts in visual attention are known to covertly enhance processing at locations away from the center of gaze, where visual resolution is low. It is unknown, however, whether selective spatial attention operates where the observer is already looking-that is, within the high-acuity foveola, the small yet disproportionally important rod-free region of the retina. Using new methods for precisely controlling retinal stimulation, here we show that covert attention flexibly improves and speeds up both detection and discrimination at loci only a fraction of a degree apart within the foveola. These findings reveal a surprisingly precise control of attention and its involvement in fine spatial vision. They show that the commonly studied covert shifts of attention away from the fovea are the expression of a global mechanism that exerts its action across the entire visual field.

High-Precision Determination of the Pion-Nucleon σ Term from Roy-Steiner Equations.

PubMed

Hoferichter, Martin; Ruiz de Elvira, Jacobo; Kubis, Bastian; Meißner, Ulf-G

2015-08-28

We present a determination of the pion-nucleon (πN) σ term σ_{πN} based on the Cheng-Dashen low-energy theorem (LET), taking advantage of the recent high-precision data from pionic atoms to pin down the πN scattering lengths as well as of constraints from analyticity, unitarity, and crossing symmetry in the form of Roy-Steiner equations to perform the extrapolation to the Cheng-Dashen point in a reliable manner. With isospin-violating corrections included both in the scattering lengths and the LET, we obtain σ_{πN}=(59.1±1.9±3.0)  MeV=(59.1±3.5)  MeV, where the first error refers to uncertainties in the πN amplitude and the second to the LET. Consequences for the scalar nucleon couplings relevant for the direct detection of dark matter are discussed.

Photomask quality evaluation using lithography simulation and precision SEM image contour data

NASA Astrophysics Data System (ADS)

Murakawa, Tsutomu; Fukuda, Naoki; Shida, Soichi; Iwai, Toshimichi; Matsumoto, Jun; Nakamura, Takayuki; Hagiwara, Kazuyuki; Matsushita, Shohei; Hara, Daisuke; Adamov, Anthony

2012-11-01

To evaluate photomask quality, the current method uses spatial imaging by optical inspection tools. This technique at 1Xnm node has a resolution limit because small defects will be difficult to extract. To simulate the mask error-enhancement factor (MEEF) influence for aggressive OPC in 1Xnm node, wide FOV contour data and tone information are derived from high precision SEM images. For this purpose we have developed a new contour data extraction algorithm with sub-nanometer accuracy resulting in a wide Field of View (FOV) SEM image: (for example, more than 10um x 10um square). We evaluated MEEF influence of high-end photomask pattern using the wide FOV contour data of "E3630 MVM-SEMTM" and lithography simulator "TrueMaskTM DS" of D2S, Inc. As a result, we can detect the "invisible defect" as the MEEF influence using the wide FOV contour data and lithography simulator.

High-Precision Determination of the Pion-Nucleon σ Term from Roy-Steiner Equations

NASA Astrophysics Data System (ADS)

Hoferichter, Martin; Ruiz de Elvira, Jacobo; Kubis, Bastian; Meißner, Ulf-G.

2015-08-01

We present a determination of the pion-nucleon (π N ) σ term σπ N based on the Cheng-Dashen low-energy theorem (LET), taking advantage of the recent high-precision data from pionic atoms to pin down the π N scattering lengths as well as of constraints from analyticity, unitarity, and crossing symmetry in the form of Roy-Steiner equations to perform the extrapolation to the Cheng-Dashen point in a reliable manner. With isospin-violating corrections included both in the scattering lengths and the LET, we obtain σπ N=(59.1 ±1.9 ±3.0 ) MeV =(59.1 ±3.5 ) MeV , where the first error refers to uncertainties in the π N amplitude and the second to the LET. Consequences for the scalar nucleon couplings relevant for the direct detection of dark matter are discussed.

OBSERVATIONAL SIGNATURES OF CONVECTIVELY DRIVEN WAVES IN MASSIVE STARS

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

Aerts, C.; Rogers, T. M.

We demonstrate observational evidence for the occurrence of convectively driven internal gravity waves (IGWs) in young massive O-type stars observed with high-precision CoRoT space photometry. This evidence results from a comparison between velocity spectra based on two-dimensional hydrodynamical simulations of IGWs in a differentially rotating massive star and the observed spectra. We also show that the velocity spectra caused by IGWs may lead to detectable line-profile variability and explain the occurrence of macroturbulence in the observed line profiles of OB stars. Our findings provide predictions that can readily be tested by including a sample of bright, slowly and rapidly rotatingmore » OB-type stars in the scientific program of the K2 mission accompanied by high-precision spectroscopy and their confrontation with multi-dimensional hydrodynamic simulations of IGWs for various masses and ages.« less

Selective attention within the foveola

PubMed Central

Poletti, Martina; Rucci, Michele; Carrasco, Marisa

2018-01-01

Efficient control of attentional resources and high-acuity vision are both fundamental for survival. Shifts in visual attention are known to covertly enhance processing at locations away from the center of gaze, where visual resolution is low. It is unknown, however, whether selective spatial attention operates where the observer already looks, i.e., within the high-acuity foveola, the small, yet disproportionally important rod-free region of the retina. Using new methods for precisely controlling retinal stimulation, here we show that covert attention flexibly improves and speeds-up both detection and discrimination at loci only a fraction of a degree apart within the foveola. These findings reveal a surprisingly precise control of attention and its involvement in fine spatial vision. They show that the commonly studied covert shifts of attention away from the fovea are the expression of a global mechanism that exerts its action across the entire visual field. PMID:28805816

Interferometric apparatus for ultra-high precision displacement measurement

NASA Technical Reports Server (NTRS)

Zhao, Feng (Inventor)

2004-01-01

A high-precision heterodyne interferometer measures relative displacement by creating a thermally-insensitive system generally not subject to polarization leakage. By using first and second light beams separated by a small frequency difference (.DELTA.f), beams of light at the first frequency (f.sub.0) are reflected by co-axial mirrors, the first mirror of which has a central aperture through which the light is transmitted to and reflected by the second mirror. Prior to detection, the light beams from the two mirrors are combined with light of the second and slightly different frequency. The combined light beams are separated according to the light from the mirrors. The change in phase (.DELTA..phi.) with respect to the two signals is proportional to the change in distance of Fiducial B by a factor of wavelength (.lambda.) divided by 4.pi. (.DELTA.L=.lambda..DELTA..phi.1/(4.pi.)). In a second embodiment, a polarizing beam splitting system can be used.

Thermospheric temperature measurement technique.

NASA Technical Reports Server (NTRS)

Hueser, J. E.; Fowler, P.

1972-01-01

A method for measurement of temperature in the earth's lower thermosphere from a high-velocity probes is described. An undisturbed atmospheric sample is admitted to the instrument by means of a free molecular flow inlet system of skimmers which avoids surface collisions of the molecules prior to detection. Measurement of the time-of-flight distribution of an initially well-localized group of nitrogen metastable molecular states produced in an open, crossed electron-molecular beam source, yields information on the atmospheric temperature. It is shown that for high vehicle velocities, the time-of-flight distribution of the metastable flux is a sensitive indicator of atmospheric temperature. The temperature measurement precision should be greater than 94% at the 99% confidence level over the range of altitudes from 120-170 km. These precision and altitude range estimates are based on the statistical consideration of the counting rates achieved with a multichannel analyzer using realistic values for system parameters.

Technology of focus detection for 193nm projection lithographic tool

NASA Astrophysics Data System (ADS)

Di, Chengliang; Yan, Wei; Hu, Song; Xu, Feng; Li, Jinglong

2012-10-01

With the shortening printing wavelength and increasing numerical aperture of lithographic tool, the depth of focus(DOF) sees a rapidly drop down trend, reach a scale of several hundred nanometers while the repeatable accuracy of focusing and leveling must be one-tenth of DOF, approximately several dozen nanometers. For this feature, this article first introduces several focusing technology, Obtained the advantages and disadvantages of various methods by comparing. Then get the accuracy of dual-grating focusing method through theoretical calculation. And the dual-grating focusing method based on photoelastic modulation is divided into coarse focusing and precise focusing method to analyze, establishing image processing model of coarse focusing and photoelastic modulation model of accurate focusing. Finally, focusing algorithm is simulated with MATLAB. In conclusion dual-grating focusing method shows high precision, high efficiency and non-contact measurement of the focal plane, meeting the demands of focusing in 193nm projection lithography.

Change Detection of Remote Sensing Images by Dt-Cwt and Mrf

NASA Astrophysics Data System (ADS)

Ouyang, S.; Fan, K.; Wang, H.; Wang, Z.

2017-05-01

Aiming at the significant loss of high frequency information during reducing noise and the pixel independence in change detection of multi-scale remote sensing image, an unsupervised algorithm is proposed based on the combination between Dual-tree Complex Wavelet Transform (DT-CWT) and Markov random Field (MRF) model. This method first performs multi-scale decomposition for the difference image by the DT-CWT and extracts the change characteristics in high-frequency regions by using a MRF-based segmentation algorithm. Then our method estimates the final maximum a posterior (MAP) according to the segmentation algorithm of iterative condition model (ICM) based on fuzzy c-means(FCM) after reconstructing the high-frequency and low-frequency sub-bands of each layer respectively. Finally, the method fuses the above segmentation results of each layer by using the fusion rule proposed to obtain the mask of the final change detection result. The results of experiment prove that the method proposed is of a higher precision and of predominant robustness properties.

Precision measurements of g1 of the proton and of the deuteron with 6 GeV electrons

NASA Astrophysics Data System (ADS)

Prok, Y.; Bosted, P.; Kvaltine, N.; Adhikari, K. P.; Adikaram, D.; Aghasyan, M.; Amaryan, M. J.; Anderson, M. D.; Anefalos Pereira, S.; Avakian, H.; Baghdasaryan, H.; Ball, J.; Baltzell, N. A.; Battaglieri, M.; Biselli, A. S.; Bono, J.; Briscoe, W. J.; Brock, J.; Brooks, W. K.; Bültmann, S.; Burkert, V. D.; Carlin, C.; Carman, D. S.; Celentano, A.; Chandavar, S.; Colaneri, L.; Cole, P. L.; Contalbrigo, M.; Cortes, O.; Crabb, D.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Dodge, G. E.; Doughty, D.; Dupre, R.; El Alaoui, A.; El Fassi, L.; Elouadrhiri, L.; Fedotov, G.; Fegan, S.; Fersch, R.; Fleming, J. A.; Forest, T. A.; Garçon, M.; Garillon, B.; Gevorgyan, N.; Ghandilyan, Y.; Gilfoyle, G. P.; Girod, F. X.; Giovanetti, K. L.; Goetz, J. T.; Gohn, W.; Gothe, R. W.; Griffioen, K. A.; Guegan, B.; Guler, N.; Hafidi, K.; Hanretty, C.; Harrison, N.; Hattawy, M.; Hicks, K.; Ho, D.; Holtrop, M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jawalkar, S.; Jiang, X.; Jo, H. S.; Joo, K.; Kalantarians, N.; Keith, C.; Keller, D.; Khandaker, M.; Kim, A.; Kim, W.; Klein, A.; Klein, F. J.; Koirala, S.; Kubarovsky, V.; Kuhn, S. E.; Kuleshov, S. V.; Lenisa, P.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Markov, N.; Mayer, M.; McKinnon, B.; Meekins, D.; Mineeva, T.; Mirazita, M.; Mokeev, V.; Montgomery, R. A.; Moutarde, H.; Movsisyan, A.; Munevar, E.; Munoz Camacho, C.; Nadel-Turonski, P.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Pappalardo, L. L.; Paremuzyan, R.; Park, K.; Peng, P.; Phillips, J. J.; Pierce, J.; Pisano, S.; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Procureur, S.; Protopopescu, D.; Puckett, A. J. R.; Raue, B. A.; Rimal, D.; Ripani, M.; Rizzo, A.; Rosner, G.; Rossi, P.; Roy, P.; Sabatié, F.; Saini, M. S.; Salgado, C.; Schott, D.; Schumacher, R. A.; Seder, E.; Sharabian, Y. G.; Simonyan, A.; Smith, C.; Smith, G.; Sober, D. I.; Sokhan, D.; Stepanyan, S. S.; Stepanyan, S.; Strakovsky, I. I.; Strauch, S.; Sytnik, V.; Taiuti, M.; Tang, W.; Tkachenko, S.; Ungaro, M.; Vernarsky, B.; Vlassov, A. V.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Weinstein, L. B.; Zachariou, N.; Zana, L.; Zhang, J.; Zhao, B.; Zhao, Z. W.; Zonta, I.; CLAS Collaboration

2014-08-01

The inclusive polarized structure functions of the proton and deuteron, g1p and g1d, were measured with high statistical precision using polarized 6 GeV electrons incident on a polarized ammonia target in Hall B at Jefferson Laboratory. Electrons scattered at laboratory angles between 18 and 45 degrees were detected using the CEBAF Large Acceptance Spectrometer (CLAS). For the usual deep inelastic region kinematics, Q2>1 GeV2 and the final-state invariant mass W >2 GeV, the ratio of polarized to unpolarized structure functions g1/F1 is found to be nearly independent of Q2 at fixed x. Significant resonant structure is apparent at values of W up to 2.3 GeV. In the framework of perturbative quantum chromodynamics, the high-W results can be used to better constrain the polarization of quarks and gluons in the nucleon, as well as high-twist contributions.

Development of the automated circulating tumor cell recovery system with microcavity array.

PubMed

Negishi, Ryo; Hosokawa, Masahito; Nakamura, Seita; Kanbara, Hisashige; Kanetomo, Masafumi; Kikuhara, Yoshihito; Tanaka, Tsuyoshi; Matsunaga, Tadashi; Yoshino, Tomoko

2015-05-15

Circulating tumor cells (CTCs) are well recognized as useful biomarker for cancer diagnosis and potential target of drug discovery for metastatic cancer. Efficient and precise recovery of extremely low concentrations of CTCs from blood has been required to increase the detection sensitivity. Here, an automated system equipped with a microcavity array (MCA) was demonstrated for highly efficient and reproducible CTC recovery. The use of MCA allows selective recovery of cancer cells from whole blood on the basis of differences in size between tumor and blood cells. Intra- and inter-assays revealed that the automated system achieved high efficiency and reproducibility equal to the assay manually performed by well-trained operator. Under optimized assay workflow, the automated system allows efficient and precise cell recovery for non-small cell lung cancer cells spiked in whole blood. The automated CTC recovery system will contribute to high-throughput analysis in the further clinical studies on large cohort of cancer patients. Copyright © 2014 Elsevier B.V. All rights reserved.

Development of High Precision Metal Micro-Electro-Mechanical-Systems Column for Portable Surface Acoustic Wave Gas Chromatograph

NASA Astrophysics Data System (ADS)

Iwaya, Takamitsu; Akao, Shingo; Sakamoto, Toshihiro; Tsuji, Toshihiro; Nakaso, Noritaka; Yamanaka, Kazushi

2012-07-01

In the field of environmental measurement and security, a portable gas chromatograph (GC) is required for the on-site analysis of multiple hazardous gases. Although the gas separation column has been downsized using micro-electro-mechanical-systems (MEMS) technology, an MEMS column made of silicon and glass still does not have sufficient robustness and a sufficiently low fabrication cost for a portable GC. In this study, we fabricated a robust and inexpensive high-precision metal MEMS column by combining diffusion-bonded etched stainless-steel plates with alignment evaluation using acoustic microscopy. The separation performance was evaluated using a desktop GC with a flame ionization detector and we achieved the high separation performance comparable to the best silicon MEMS column fabricated using a dynamic coating method. As an application, we fabricated a palm-size surface acoustic wave (SAW) GC combining this column with a ball SAW sensor and succeeded in separating and detecting a mixture of volatile organic compounds.

Precision measurements of g1 of the proton and the deuteron with 6 GeV electrons

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

Prok, Yelena; Bosted, Peter; Kvaltine, Nicholas

2014-08-01

The inclusive polarized structure functions of the proton and deuteron, g1p and g1d, were measured with high statistical precision using polarized 6 GeV electrons incident on a polarized ammonia target in Hall B at Jefferson Laboratory. Electrons scattered at lab angles between 18 and 45 degrees were detected using the CEBAF Large Acceptance Spectrometer (CLAS). For the usual DIS kinematics, Q^2>1 GeV^2 and the final-state invariant mass W>2 GeV, the ratio of polarized to unpolarized structure functions g1/F1 is found to be nearly independent of Q^2 at fixed x. Significant resonant structure is apparent at values of W up tomore » 2.3 GeV. In the framework of perturbative QCD, the high-W results can be used to better constrain the polarization of quarks and gluons in the nucleon, as well as high-twist contributions.« less

The prospects of pulsar timing with new-generation radio telescopes and the Square Kilometre Array.

PubMed

Stappers, B W; Keane, E F; Kramer, M; Possenti, A; Stairs, I H

2018-05-28

Pulsars are highly magnetized and rapidly rotating neutron stars. As they spin, the lighthouse-like beam of radio emission from their magnetic poles sweeps across the Earth with a regularity approaching that of the most precise clocks known. This precision combined with the extreme environments in which they are found, often in compact orbits with other neutron stars and white dwarfs, makes them excellent tools for studying gravity. Present and near-future pulsar surveys, especially those using the new generation of telescopes, will find more extreme binary systems and pulsars that are more precise 'clocks'. These telescopes will also greatly improve the precision to which we can measure the arrival times of the pulses. The Square Kilometre Array will revolutionize pulsar searches and timing precision. The increased number of sources will reveal rare sources, including possibly a pulsar-black hole binary, which can provide the most stringent tests of strong-field gravity. The improved timing precision will reveal new phenomena and also allow us to make a detection of gravitational waves in the nanohertz frequency regime. It is here where we expect to see the signature of the binary black holes that are formed as galaxies merge throughout cosmological history.This article is part of a discussion meeting issue 'The promises of gravitational-wave astronomy'. © 2018 The Author(s).

An ultra-precision tool nanoindentation instrument for replication of single point diamond tool cutting edges

NASA Astrophysics Data System (ADS)

Cai, Yindi; Chen, Yuan-Liu; Xu, Malu; Shimizu, Yuki; Ito, So; Matsukuma, Hiraku; Gao, Wei

2018-05-01

Precision replication of the diamond tool cutting edge is required for non-destructive tool metrology. This paper presents an ultra-precision tool nanoindentation instrument designed and constructed for replication of the cutting edge of a single point diamond tool onto a selected soft metal workpiece by precisely indenting the tool cutting edge into the workpiece surface. The instrument has the ability to control the indentation depth with a nanometric resolution, enabling the replication of tool cutting edges with high precision. The motion of the diamond tool along the indentation direction is controlled by the piezoelectric actuator of a fast tool servo (FTS). An integrated capacitive sensor of the FTS is employed to detect the displacement of the diamond tool. The soft metal workpiece is attached to an aluminum cantilever whose deflection is monitored by another capacitive sensor, referred to as an outside capacitive sensor. The indentation force and depth can be accurately evaluated from the diamond tool displacement, the cantilever deflection and the cantilever spring constant. Experiments were carried out by replicating the cutting edge of a single point diamond tool with a nose radius of 2.0 mm on a copper workpiece surface. The profile of the replicated tool cutting edge was measured using an atomic force microscope (AFM). The effectiveness of the instrument in precision replication of diamond tool cutting edges is well-verified by the experimental results.

Study on high power ultraviolet laser oil detection system

NASA Astrophysics Data System (ADS)

Jin, Qi; Cui, Zihao; Bi, Zongjie; Zhang, Yanchao; Tian, Zhaoshuo; Fu, Shiyou

2018-03-01

Laser Induce Fluorescence (LIF) is a widely used new telemetry technology. It obtains information about oil spill and oil film thickness by analyzing the characteristics of stimulated fluorescence and has an important application in the field of rapid analysis of water composition. A set of LIF detection system for marine oil pollution is designed in this paper, which uses 355nm high-energy pulsed laser as the excitation light source. A high-sensitivity image intensifier is used in the detector. The upper machine sends a digital signal through a serial port to achieve nanoseconds range-gated width control for image intensifier. The target fluorescence spectrum image is displayed on the image intensifier by adjusting the delay time and the width of the pulse signal. The spectral image is coupled to CCD by lens imaging to achieve spectral display and data analysis function by computer. The system is used to detect the surface of the floating oil film in the distance of 25m to obtain the fluorescence spectra of different oil products respectively. The fluorescence spectra of oil products are obvious. The experimental results show that the system can realize high-precision long-range fluorescence detection and reflect the fluorescence characteristics of the target accurately, with broad application prospects in marine oil pollution identification and oil film thickness detection.

Functionalized vertical GaN micro pillar arrays with high signal-to-background ratio for detection and analysis of proteins secreted from breast tumor cells.

PubMed

Choi, Mun-Ki; Kim, Gil-Sung; Jeong, Jin-Tak; Lim, Jung-Taek; Lee, Won-Yong; Umar, Ahmad; Lee, Sang-Kwon

2017-11-02

The detection of cancer biomarkers has recently attracted significant attention as a means of determining the correct course of treatment with targeted therapeutics. However, because the concentration of these biomarkers in blood is usually relatively low, highly sensitive biosensors for fluorescence imaging and precise detection are needed. In this study, we have successfully developed vertical GaN micropillar (MP) based biosensors for fluorescence sensing and quantitative measurement of CA15-3 antigens. The highly ordered vertical GaN MP arrays result in the successful immobilization of CA15-3 antigens on each feature of the arrays, thereby allowing the detection of an individual fluorescence signal from the top surface of the arrays owing to the high regularity of fluorophore-tagged MP spots and relatively low background signal. Therefore, our fluorescence-labeled and CA15-3 functionalized vertical GaN-MP-based biosensor is suitable for the selective quantitative analysis of secreted CA15-3 antigens from MCF-7 cell lines, and helps in the early diagnosis and prognosis of serious diseases as well as the monitoring of the therapeutic response of breast cancer patients.

Sensing Using Rare-Earth-Doped Upconversion Nanoparticles

PubMed Central

Hao, Shuwei; Chen, Guanying; Yang, Chunhui

2013-01-01

Optical sensing plays an important role in theranostics due to its capability to detect hint biochemical entities or molecular targets as well as to precisely monitor specific fundamental psychological processes. Rare-earth (RE) doped upconversion nanoparticles (UCNPs) are promising for these endeavors due to their unique frequency converting capability; they emit efficient and sharp visible or ultraviolet (UV) luminescence via use of ladder-like energy levels of RE ions when excited at near infrared (NIR) light that are silent to tissues. These features allow not only a high penetration depth in biological tissues but also a high detection sensitivity. Indeed, the energy transfer between UCNPs and biomolecular or chemical indicators provide opportunities for high-sensitive bio- and chemical-sensing. A temperature-sensitive change of the intensity ratio between two close UC bands promises them for use in temperature mapping of a single living cell. In this work, we review recent investigations on using UCNPs for the detection of biomolecules (avidin, ATP, etc.), ions (cyanide, mecury, etc.), small gas molecules (oxygen, carbon dioxide, ammonia, etc.), as well as for in vitro temperature sensing. We also briefly summarize chemical methods in synthesizing UCNPs of high efficiency that are important for the detection limit. PMID:23650480

High-precision photometry by telescope defocusing - VII. The ultrashort period planet WASP-103

NASA Astrophysics Data System (ADS)

Southworth, John; Mancini, L.; Ciceri, S.; Budaj, J.; Dominik, M.; Figuera Jaimes, R.; Haugbølle, T.; Jørgensen, U. G.; Popovas, A.; Rabus, M.; Rahvar, S.; von Essen, C.; Schmidt, R. W.; Wertz, O.; Alsubai, K. A.; Bozza, V.; Bramich, D. M.; Calchi Novati, S.; D'Ago, G.; Hinse, T. C.; Henning, Th.; Hundertmark, M.; Juncher, D.; Korhonen, H.; Skottfelt, J.; Snodgrass, C.; Starkey, D.; Surdej, J.

2015-02-01

We present 17 transit light curves of the ultrashort period planetary system WASP-103, a strong candidate for the detection of tidally-induced orbital decay. We use these to establish a high-precision reference epoch for transit timing studies. The time of the reference transit mid-point is now measured to an accuracy of 4.8 s, versus 67.4 s in the discovery paper, aiding future searches for orbital decay. With the help of published spectroscopic measurements and theoretical stellar models, we determine the physical properties of the system to high precision and present a detailed error budget for these calculations. The planet has a Roche lobe filling factor of 0.58, leading to a significant asphericity; we correct its measured mass and mean density for this phenomenon. A high-resolution Lucky Imaging observation shows no evidence for faint stars close enough to contaminate the point spread function of WASP-103. Our data were obtained in the Bessell RI and the SDSS griz passbands and yield a larger planet radius at bluer optical wavelengths, to a confidence level of 7.3σ. Interpreting this as an effect of Rayleigh scattering in the planetary atmosphere leads to a measurement of the planetary mass which is too small by a factor of 5, implying that Rayleigh scattering is not the main cause of the variation of radius with wavelength.

Correlation matching method for high-precision position detection of optical vortex using Shack-Hartmann wavefront sensor.

PubMed

Huang, Chenxi; Huang, Hongxin; Toyoda, Haruyoshi; Inoue, Takashi; Liu, Huafeng

2012-11-19

We propose a new method for realizing high-spatial-resolution detection of singularity points in optical vortex beams. The method uses a Shack-Hartmann wavefront sensor (SHWS) to record a Hartmanngram. A map of evaluation values related to phase slope is then calculated from the Hartmanngram. The position of an optical vortex is determined by comparing the map with reference maps that are calculated from numerically created spiral phases having various positions. Optical experiments were carried out to verify the method. We displayed various spiral phase distribution patterns on a phase-only spatial light modulator and measured the resulting singularity point using the proposed method. The results showed good linearity in detecting the position of singularity points. The RMS error of the measured position of the singularity point was approximately 0.056, in units normalized to the lens size of the lenslet array used in the SHWS.

NegBio: a high-performance tool for negation and uncertainty detection in radiology reports.

PubMed

Peng, Yifan; Wang, Xiaosong; Lu, Le; Bagheri, Mohammadhadi; Summers, Ronald; Lu, Zhiyong

2018-01-01

Negative and uncertain medical findings are frequent in radiology reports, but discriminating them from positive findings remains challenging for information extraction. Here, we propose a new algorithm, NegBio, to detect negative and uncertain findings in radiology reports. Unlike previous rule-based methods, NegBio utilizes patterns on universal dependencies to identify the scope of triggers that are indicative of negation or uncertainty. We evaluated NegBio on four datasets, including two public benchmarking corpora of radiology reports, a new radiology corpus that we annotated for this work, and a public corpus of general clinical texts. Evaluation on these datasets demonstrates that NegBio is highly accurate for detecting negative and uncertain findings and compares favorably to a widely-used state-of-the-art system NegEx (an average of 9.5% improvement in precision and 5.1% in F1-score). https://github.com/ncbi-nlp/NegBio.

Optomechanical terahertz detection with single meta-atom resonator.

PubMed

Belacel, Cherif; Todorov, Yanko; Barbieri, Stefano; Gacemi, Djamal; Favero, Ivan; Sirtori, Carlo

2017-11-17

Most of the common technologies for detecting terahertz photons (>1 THz) at room temperature rely on slow thermal devices. The realization of fast and sensitive detectors in this frequency range is indeed a notoriously difficult task. Here we propose a novel device consisting of a subwavelength terahertz meta-atom resonator, which integrates a nanomechanical element and allows energy exchange between the mechanical motion and the electromagnetic degrees of freedom. An incident terahertz wave thus produces a nanomechanical signal that can be read out optically with high precision. We exploit this concept to demonstrate a terahertz detector that operates at room temperature with high sensitivity and a much higher frequency response compared to standard detectors. Beyond the technological issue of terahertz detection, our architecture opens up new perspectives for fundamental science of light-matter interaction at terahertz frequencies, combining optomechanical approaches with semiconductor quantum heterostructures.

Detection of interstellar ethyl cyanide

NASA Technical Reports Server (NTRS)

Johnson, D. R.; Lovas, F. J.; Gottlieb, C. A.; Gottlieb, E. W.; Litvak, M. M.; Thaddeus, P.; Guelin, M.

1977-01-01

Twenty-four millimeter-wave emission lines of ethyl cyanide (CH3CH2CN) have been detected in the Orion Nebula (OMC-1) and seven in Sgr B2. To derive precise radial velocities from the astronomical data, a laboratory measurement of the rotational spectrum of ethyl cyanide has been made at frequencies above 41 GHz. In OMC-1, the rotational temperature of ethyl cyanide is 90 K (in good agreement with other molecules), the local-standard-of-rest radial velocity is 4.5 + or - 1.0 km/s (versus 8.5 km/s for most molecules), and the column density is 1.8 by 10 to the 14th power per sq cm (a surprisingly high figure for a complicated molecule). The high abundance of ethyl cyanide in the Orion Nebula suggests that ethane and perhaps larger saturated hydrocarbons may be common constituents of molecular clouds and have escaped detection only because they are nonpolar or only weakly polar.

Development of validated high-temperature reverse-phase UHPLC-PDA analytical method for simultaneous analysis of five natural isothiocyanates in cruciferous vegetables.

PubMed

Robin; Arora, Rohit; Arora, Saroj; Vig, Adarsh Pal

2018-01-15

In the present study reverse-phase UHPLC-PDA technique was developed at 60°C for simultaneous quantification of allyl, 3-butenyl, 4-(methylthio)butyl, benzyl and phenethyl isothiocyanates. The validation parameter showed a very good linearity, with a correlation coefficient of 1.00 for all detected standard analytes. Also, high precision and accuracy were observed with lowest obtained values of 1.39% and 99.1%, respectively. Different varieties of three plants, viz. Brassica rapa var. rapa L., Raphanus sativus L. var. oleiformis Pers. and Eruca sativa Mill., were analyzed with this method. After analysis, 4-(methylthio)butyl isothiocyanate was observed to be the major component in the varieties of arugula. Allyl, benzyl and phenethyl isothiocyanates were detected in turnip varieties and, in addition, 3-butenyl isothiocyanate was detected in radish varieties. Copyright © 2017 Elsevier Ltd. All rights reserved.

Highly sensitive troponin T for risk stratification of acutely destabilized heart failure.

PubMed

Pascual-Figal, Domingo A; Casas, Teresa; Ordonez-Llanos, Jordi; Manzano-Fernández, Sergio; Bonaque, Juan C; Boronat, Miguel; Muñoz-Esparza, Carmen; Valdés, Mariano; Januzzi, James L

2012-06-01

A highly sensitive assay for troponin T (hsTnT) has been recently developed, which allows for the detection of even minor myocardial necrosis with high precision. It remains unexplored whether hsTnT provides incremental prognostic accuracy beyond conventional (c)TnT in patients with acutely decompensated heart failure (ADHF). A total of 202 consecutive patients admitted with ADHF and without criteria for acute myocardial infarction were studied. Troponin T was measured using the highly sensitive assay and compared with the conventional method. Patients were clinically followed up at a median of 406 days, with a primary outcome measure of all-cause mortality. The high-sensitive assay detected measurable TnT in 98% of patients vs 56% for cTnT; 81% had an hsTnT above the 99th percentile for a healthy reference population, and it reclassified 60% of those with undetectable cTnT. Both TnT methods predicted the risk of death in adjusted multivariable Cox regression analyses, without a superiority of hsTnT over cTnT in the entire population (area under the curve 0.67 vs 0.71, P = .2). Among patients with a cTnT below 0.03 ng/mL (the lowest cut-point with <10% imprecision; n = 134), solely hsTnT improved the prediction of death over clinical risk factors (relative integrated discrimination improvement +36%, P = .01) and hsTnT above 20 pg/mL identified a significant higher risk of death (hazard ratio 4.7, 95% CI 1.6-13.8, P = .005). Among patients with ADHF, myocardial necrosis (as detected with the hsTnT assay) was nearly ubiquitous. The highly sensitive assay for TnT provides comparable prognostic information to cTnT overall, but among those in whom the cTnT method was less precise or frankly negative, the hsTnT assay provided prognostic information. Copyright © 2012 Mosby, Inc. All rights reserved.

Animal board invited review: precision livestock farming for dairy cows with a focus on oestrus detection.

PubMed

Mottram, T

2016-10-01

Dairy cows are high value farm animals requiring careful management to achieve the best results. Since the advent of robotic and high throughput milking, the traditional few minutes available for individual human attention daily has disappeared and new automated technologies have been applied to improve monitoring of dairy cow production, nutrition, fertility, health and welfare. Cows milked by robots must meet legal requirements to detect healthy milk. This review focuses on emerging technical approaches in those areas of high cost to the farmer (fertility, metabolic disorders, mastitis, lameness and calving). The availability of low cost tri-axial accelerometers and wireless telemetry has allowed accurate models of behaviour to be developed and sometimes combined with rumination activity detected by acoustic sensors to detect oestrus; other measures (milk and skin temperature, electronic noses, milk yield) have been abandoned. In-line biosensors have been developed to detect markers for ovulation, pregnancy, lactose, mastitis and metabolic changes. Wireless telemetry has been applied to develop boluses for monitoring the rumen pH and temperature to detect metabolic disorders. Udder health requires a multisensing approach due to the varying inflammatory responses collectively described as mastitis. Lameness can be detected by walk over weigh cells, but also by various types of video image analysis and speed measurement. Prediction and detection of calving time is an area of active research mostly focused on behavioural change.

Strawberry Maturity Neural Network Detectng System Based on Genetic Algorithm

NASA Astrophysics Data System (ADS)

Xu, Liming

The quick and non-detective detection of agriculture product is one of the measures to increase the precision and productivity of harvesting and grading. Having analyzed H frequency of different maturities in different light intensities, the results show that H frequency for the same maturity has little influence in different light intensities; Under the same light intensity, three strawberry maturities are changing in order. After having confirmed the H frequency section to distinguish the different strawberry maturity, the triplelayer feed-forward neural network system to detect strawberry maturity was designed by using genetic algorithm. The test results show that the detecting precision ratio is 91.7%, it takes 160ms to distinguish one strawberry. Therefore, the online non-detective detecting the strawberry maturity could be realized.

Benchmark for Peak Detection Algorithms in Fiber Bragg Grating Interrogation and a New Neural Network for its Performance Improvement

PubMed Central

Negri, Lucas; Nied, Ademir; Kalinowski, Hypolito; Paterno, Aleksander

2011-01-01

This paper presents a benchmark for peak detection algorithms employed in fiber Bragg grating spectrometric interrogation systems. The accuracy, precision, and computational performance of currently used algorithms and those of a new proposed artificial neural network algorithm are compared. Centroid and gaussian fitting algorithms are shown to have the highest precision but produce systematic errors that depend on the FBG refractive index modulation profile. The proposed neural network displays relatively good precision with reduced systematic errors and improved computational performance when compared to other networks. Additionally, suitable algorithms may be chosen with the general guidelines presented. PMID:22163806

Neural timing signal for precise tactile timing judgments

PubMed Central

Watanabe, Junji; Nishida, Shin'ya

2016-01-01

The brain can precisely encode the temporal relationship between tactile inputs. While behavioural studies have demonstrated precise interfinger temporal judgments, the underlying neural mechanism remains unknown. Computationally, two kinds of neural responses can act as the information source. One is the phase-locked response to the phase of relatively slow inputs, and the other is the response to the amplitude change of relatively fast inputs. To isolate the contributions of these components, we measured performance of a synchrony judgment task for sine wave and amplitude-modulation (AM) wave stimuli. The sine wave stimulus was a low-frequency sinusoid, with the phase shifted in the asynchronous stimulus. The AM wave stimulus was a low-frequency sinusoidal AM of a 250-Hz carrier, with only the envelope shifted in the asynchronous stimulus. In the experiment, three stimulus pairs, two synchronous ones and one asynchronous one, were sequentially presented to neighboring fingers, and participants were asked to report which one was the asynchronous pair. We found that the asynchrony of AM waves could be detected as precisely as single impulse pair, with the threshold asynchrony being ∼20 ms. On the other hand, the asynchrony of sine waves could not be detected at all in the range from 5 to 30 Hz. Our results suggest that the timing signal for tactile judgments is provided not by the stimulus phase information but by the envelope of the response of the high-frequency-sensitive Pacini channel (PC), although they do not exclude a possible contribution of the envelope of non-PCs. PMID:26843600

Environmental applications of single collector high resolution ICP-MS.

PubMed

Krachler, Michael

2007-08-01

The number of environmental applications of single collector high resolution ICP-MS (HR-ICP-MS) has increased rapidly in recent years. There are many factors that contribute to make HR-ICP-MS a very powerful tool in environmental analysis. They include the extremely low detection limits achievable, tremendously high sensitivity, the ability to separate ICP-MS signals of the analyte from spectral interferences, enabling the reliable determination of many trace elements, and the reasonable precision of isotope ratio measurements. These assets are improved even further using high efficiency sample introduction systems. Therefore, external factors such as the stability of laboratory blanks are frequently the limiting factor in HR-ICP-MS analysis rather than the detection power. This review aims to highlight the most recent applications of HR-ICP-MS in this sector, focusing on matrices and applications where the superior capabilities of the instrumental technique are most useful and often ultimately required.

High-Precision Studies of Compact Variable Stars

NASA Astrophysics Data System (ADS)

Bloemen, Steven

2014-10-01

This book, which is a reworked and updated version of Steven Bloemen's original PhD thesis, reports on several high-precision studies of compact variable stars. Its strength lies in the large variety of observational, theoretical and instrumentation techniques that are presented and used and paves the way towards new and detailed asteroseismic applications of single and binary subdwarf stars. Close binary stars are studied using high cadence spectroscopic datasets collected with state of the art electron multiplying CCDs and analysed using Doppler tomography visualization techniques. The work touches upon instrumentation, presenting the calibration of a new fast, multi-colour camera installed at the Mercator Telescope on La Palma. The thesis also includes theoretical work on the computation of the temperature range in which stellar oscillations can be driven in subdwarf B-stars. Finally, the highlight of the thesis is the measurement of velocities of stars using only photometric data from NASA's Kepler satellite. Doppler beaming causes stars to appear slightly brighter when they move towards us in their orbits, and this subtle effect can be seen in Kepler's brightness measurements. The thesis presents the first validation of such velocity measurements using independent spectroscopic measurements. Since the detection and validation of this Doppler beaming effect, it has been used in tens of studies to detect and characterize binary star systems, which are key calibrators in stellar astronomy.

Development and Validation of a Simultaneous RP-HPLCUV/DAD Method for Determination of Polyphenols in Gels Containing S. terebinthifolius Raddi (Anacardiaceae)

PubMed Central

Carvalho, Melina G.; Aragão, Cícero F. S; Raffin, Fernanda N.; de L. Moura, Túlio F. A.

2017-01-01

Topical gels containing extracts of Schinus terebinthifolius have been used to treat bacterial vaginosis. It has been reported that this species has antimicrobial, anti-inflammatory and anti-ulcerogenic properties, which can be attributed to the presence of phenolic compounds. In this work, a sensitive and selective reversed-phase HPLC-UV/DAD method for the simultaneous assay of six polyphenols that could be present in S. terebinthifolius was developed. The method was shown to be accurate and precise. Peak purity and similarity index both exceeded 0.99. Calibration curves were linear over the concentration range studied, with correlation coefficients between 0.9931 and 0.9974. This method was used to determine the polyphenol content of a hydroalcoholic extract and pharmacy-compounded vaginal gel. Although the method is useful to assess the 6 phenolic compounds, some compounds could not be detected in the products. SUMMARY A sensitive, selective, accurate and precise reversed-phase HPLC-UV/DAD method for the simultaneous assay of six polyphenols in S. terebinthifolius Raddi Abbreviations used: RP-HPLC-UV/DAD: Reverse Phase High Performance Liquid Chromatograph with Ultraviolet and Diode Array Detector, HPLC: High Performance Liquid Chromatograph, HPLC-UV: High Performance Liquid Chromatograph with Ultraviolet Detector, ANVISA: Brazilian National Health Surveillance Agency, LOD: Limit of detection, LOQ: Limit of quantitation PMID:28539726

Improving cervical region of interest by eliminating vaginal walls and cotton-swabs for automated image analysis

NASA Astrophysics Data System (ADS)

Venkataraman, Sankar; Li, Wenjing

2008-03-01

Image analysis for automated diagnosis of cervical cancer has attained high prominence in the last decade. Automated image analysis at all levels requires a basic segmentation of the region of interest (ROI) within a given image. The precision of the diagnosis is often reflected by the precision in detecting the initial region of interest, especially when some features outside the ROI mimic the ones within the same. Work described here discusses algorithms that are used to improve the cervical region of interest as a part of automated cervical image diagnosis. A vital visual aid in diagnosing cervical cancer is the aceto-whitening of the cervix after the application of acetic acid. Color and texture are used to segment acetowhite regions within the cervical ROI. Vaginal walls along with cottonswabs sometimes mimic these essential features leading to several false positives. Work presented here is focused towards detecting in-focus vaginal wall boundaries and then extrapolating them to exclude vaginal walls from the cervical ROI. In addition, discussed here is a marker-controlled watershed segmentation that is used to detect cottonswabs from the cervical ROI. A dataset comprising 50 high resolution images of the cervix acquired after 60 seconds of acetic acid application were used to test the algorithm. Out of the 50 images, 27 benefited from a new cervical ROI. Significant improvement in overall diagnosis was observed in these images as false positives caused by features outside the actual ROI mimicking acetowhite region were eliminated.

Ultrahigh-Sensitivity Piezoresistive Pressure Sensors for Detection of Tiny Pressure.

PubMed

Li, Hongwei; Wu, Kunjie; Xu, Zeyang; Wang, Zhongwu; Meng, Yancheng; Li, Liqiang

2018-06-20

High-sensitivity pressure sensors are crucial for the ultrasensitive touch technology and E-skin, especially at the tiny-pressure range below 100 Pa. However, it is highly challenging to substantially promote sensitivity beyond the current level at several to 200 kPa -1 and to improve the detection limit lower than 0.1 Pa, which is significant for the development of pressure sensors toward ultrasensitive and highly precise detection. Here, we develop an efficient strategy to greatly improve the sensitivity near to 2000 kPa -1 using short-channel coplanar device structure and sharp microstructure, which is systematically proposed for the first time and rationalized by the mathematic calculation and analysis. Significantly, benefiting from the ultrahigh sensitivity, the detection limit is improved to be as small as 0.075 Pa. The sensitivity and detection limit are both superior to the current levels and far surpass the function of human skin. Furthermore, the sensor shows fast response time (50 μs), excellent reproducibility and stability, and low power consumption. Remarkably, the sensor shows excellent detection capacity in the tiny-pressure range, including light-emitting diode switching with a pressure of 7 Pa, ringtone (2-20 Pa) recognition, and ultrasensitive (0.1 Pa) electronic glove. This work represents a performance and strategic progress in the field of pressure sensing.

A special vegetation index for the weed detection in sensor based precision agriculture.

PubMed

Langner, Hans-R; Böttger, Hartmut; Schmidt, Helmut

2006-06-01

Many technologies in precision agriculture (PA) require image analysis and image- processing with weed and background differentiations. The detection of weeds on mulched cropland is one important image-processing task for sensor based precision herbicide applications. The article introduces a special vegetation index, the Difference Index with Red Threshold (DIRT), for the weed detection on mulched croplands. Experimental investigations in weed detection on mulched areas point out that the DIRT performs better than the Normalized Difference Vegetation Index (NDVI). The result of the evaluation with four different decision criteria indicate, that the new DIRT gives the highest reliability in weed/background differentiation on mulched areas. While using the same spectral bands (infrared and red) as the NDVI, the new DIRT is more suitable for weed detection than the other vegetation indices and requires only a small amount of additional calculation power. The new vegetation index DIRT was tested on mulched areas during automatic ratings with a special weed camera system. The test results compare the new DIRT and three other decision criteria: the difference between infrared and red intensity (Diff), the soil-adjusted quotient between infrared and red intensity (Quotient) and the NDVI. The decision criteria were compared with the definition of a worse case decision quality parameter Q, suitable for mulched croplands. Although this new index DIRT needs further testing, the index seems to be a good decision criterion for the weed detection on mulched areas and should also be useful for other image processing applications in precision agriculture. The weed detection hardware and the PC program for the weed image processing were developed with funds from the German Federal Ministry of Education and Research (BMBF).

Computer-aided detection of human cone photoreceptor inner segments using multi-scale circular voting

NASA Astrophysics Data System (ADS)

Liu, Jianfei; Dubra, Alfredo; Tam, Johnny

2016-03-01

Cone photoreceptors are highly specialized cells responsible for the origin of vision in the human eye. Their inner segments can be noninvasively visualized using adaptive optics scanning light ophthalmoscopes (AOSLOs) with nonconfocal split detection capabilities. Monitoring the number of cones can lead to more precise metrics for real-time diagnosis and assessment of disease progression. Cell identification in split detection AOSLO images is hindered by cell regions with heterogeneous intensity arising from shadowing effects and low contrast boundaries due to overlying blood vessels. Here, we present a multi-scale circular voting approach to overcome these challenges through the novel combination of: 1) iterative circular voting to identify candidate cells based on their circular structures, 2) a multi-scale strategy to identify the optimal circular voting response, and 3) clustering to improve robustness while removing false positives. We acquired images from three healthy subjects at various locations on the retina and manually labeled cell locations to create ground-truth for evaluating the detection accuracy. The images span a large range of cell densities. The overall recall, precision, and F1 score were 91±4%, 84±10%, and 87±7% (Mean±SD). Results showed that our method for the identification of cone photoreceptor inner segments performs well even with low contrast cell boundaries and vessel obscuration. These encouraging results demonstrate that the proposed approach can robustly and accurately identify cells in split detection AOSLO images.

Automatic Fabric Defect Detection with a Multi-Scale Convolutional Denoising Autoencoder Network Model.

PubMed

Mei, Shuang; Wang, Yudan; Wen, Guojun

2018-04-02

Fabric defect detection is a necessary and essential step of quality control in the textile manufacturing industry. Traditional fabric inspections are usually performed by manual visual methods, which are low in efficiency and poor in precision for long-term industrial applications. In this paper, we propose an unsupervised learning-based automated approach to detect and localize fabric defects without any manual intervention. This approach is used to reconstruct image patches with a convolutional denoising autoencoder network at multiple Gaussian pyramid levels and to synthesize detection results from the corresponding resolution channels. The reconstruction residual of each image patch is used as the indicator for direct pixel-wise prediction. By segmenting and synthesizing the reconstruction residual map at each resolution level, the final inspection result can be generated. This newly developed method has several prominent advantages for fabric defect detection. First, it can be trained with only a small amount of defect-free samples. This is especially important for situations in which collecting large amounts of defective samples is difficult and impracticable. Second, owing to the multi-modal integration strategy, it is relatively more robust and accurate compared to general inspection methods (the results at each resolution level can be viewed as a modality). Third, according to our results, it can address multiple types of textile fabrics, from simple to more complex. Experimental results demonstrate that the proposed model is robust and yields good overall performance with high precision and acceptable recall rates.

Relative receiver autonomous integrity monitoring for future GNSS-based aircraft navigation

NASA Astrophysics Data System (ADS)

Gratton, Livio Rafael

The Global Positioning System (GPS) has enabled reliable, safe, and practical aircraft positioning for en-route and non-precision phases of flight for more than a decade. Intense research is currently devoted to extending the use of Global Navigation Satellite Systems (GNSS), including GPS, to precision approach and landing operations. In this context, this work is focused on the development, analysis, and verification of the concept of Relative Receiver Autonomous Integrity Monitoring (RRAIM) and its potential applications to precision approach navigation. RRAIM fault detection algorithms are developed, and associated mathematical bounds on position error are derived. These are investigated as possible solutions to some current key challenges in precision approach navigation, discussed below. Augmentation systems serving continent-size areas (like the Wide Area Augmentation System or WAAS) allow certain precision approach operations within the covered region. More and better satellites, with dual frequency capabilities, are expected to be in orbit in the mid-term future, which will potentially allow WAAS-like capabilities worldwide with a sparse ground station network. Two main challenges in achieving this goal are (1) ensuring that navigation fault detection functions are fast enough to alert worldwide users of hazardously misleading information, and (2) minimizing situations in which navigation is unavailable because the user's local satellite geometry is insufficient for safe position estimation. Local augmentation systems (implemented at individual airports, like the Local Area Augmentation System or LAAS) have the potential to allow precision approach and landing operations by providing precise corrections to user-satellite range measurements. An exception to these capabilities arises during ionospheric storms (caused by solar activity), when hazardous situations can exist with residual range errors several orders of magnitudes higher than nominal. Until dual frequency civil GPS signals are available, the ability to provide integrity during ionospheric storms, without excessive loss of availability is a major challenge. For all users, with or without augmentation, some situations cause short duration losses of satellites in view. Two examples are aircraft banking during turns and ionospheric scintillation. The loss of range signals can translate into gaps in good satellite geometry, and the resulting challenge is to ensure navigation continuity by bridging these gaps, while simultaneously maintaining high integrity. It is shown that the RRAIM methods developed in this research can be applied to mitigate each of these obstacles to safe and reliable precision aircraft navigation.

Quantitative analysis of benzodiazepines in vitreous humor by high-performance liquid chromatography

PubMed Central

Bazmi, Elham; Behnoush, Behnam; Akhgari, Maryam; Bahmanabadi, Leila

2016-01-01

Objective: Benzodiazepines are frequently screened drugs in emergency toxicology, drugs of abuse testing, and in forensic cases. As the variations of benzodiazepines concentrations in biological samples during bleeding, postmortem changes, and redistribution could be biasing forensic medicine examinations, hence selecting a suitable sample and a validated accurate method is essential for the quantitative analysis of these main drug categories. The aim of this study was to develop a valid method for the determination of four benzodiazepines (flurazepam, lorazepam, alprazolam, and diazepam) in vitreous humor using liquid–liquid extraction and high-performance liquid chromatography. Methods: Sample preparation was carried out using liquid–liquid extraction with n-hexane: ethyl acetate and subsequent detection by high-performance liquid chromatography method coupled to diode array detector. This method was applied to quantify benzodiazepines in 21 authentic vitreous humor samples. Linear curve for each drug was obtained within the range of 30–3000 ng/mL with coefficient of correlation higher than 0.99. Results: The limit of detection and quantitation were 30 and 100 ng/mL respectively for four drugs. The method showed an appropriate intra- and inter-day precision (coefficient of variation < 10%). Benzodiazepines recoveries were estimated to be over 80%. The method showed high selectivity; no additional peak due to interfering substances in samples was observed. Conclusion: The present method was selective, sensitive, accurate, and precise for the quantitative analysis of benzodiazepines in vitreous humor samples in forensic toxicology laboratory. PMID:27635251

Super-resolution imaging applied to moving object tracking

NASA Astrophysics Data System (ADS)

Swalaganata, Galandaru; Ratna Sulistyaningrum, Dwi; Setiyono, Budi

2017-10-01

Moving object tracking in a video is a method used to detect and analyze changes that occur in an object that being observed. Visual quality and the precision of the tracked target are highly wished in modern tracking system. The fact that the tracked object does not always seem clear causes the tracking result less precise. The reasons are low quality video, system noise, small object, and other factors. In order to improve the precision of the tracked object especially for small object, we propose a two step solution that integrates a super-resolution technique into tracking approach. First step is super-resolution imaging applied into frame sequences. This step was done by cropping the frame in several frame or all of frame. Second step is tracking the result of super-resolution images. Super-resolution image is a technique to obtain high-resolution images from low-resolution images. In this research single frame super-resolution technique is proposed for tracking approach. Single frame super-resolution was a kind of super-resolution that it has the advantage of fast computation time. The method used for tracking is Camshift. The advantages of Camshift was simple calculation based on HSV color that use its histogram for some condition and color of the object varies. The computational complexity and large memory requirements required for the implementation of super-resolution and tracking were reduced and the precision of the tracked target was good. Experiment showed that integrate a super-resolution imaging into tracking technique can track the object precisely with various background, shape changes of the object, and in a good light conditions.

Real-time monitoring of drowsiness through wireless nanosensor systems

NASA Astrophysics Data System (ADS)

Ramasamy, Mouli; Varadan, Vijay K.

2016-04-01

Detection of sleepiness and drowsiness in human beings has been a daunting task for both engineering and medical technologies. Accuracy, precision and promptness of detection have always been an issue that has to be dealt by technologists. Generally, the bio potential signals - ECG, EOG, EEG and EMG are used to classify and discriminate sleep from being awake. However, the potential drawbacks may be high false detections, low precision, obtrusiveness, aftermath analysis, etc. To overcome the disadvantages, this paper reviews the design aspects of a wireless and a real time monitoring system to track sleep and detect fatigue. This concept involves the use of EOG and EEG to measure the blink rate and asses the person's condition. In this user friendly and intuitive approach, EOG and EEG signals are obtained by the textile based nanosensors mounted on the inner side of a flexible headband. The acquired signals are then electrically transmitted to the data processing and transmission unit, which transmits the processed data to the receiver/monitoring module through ZigBee communication. This system is equipped with a software program to process, feature extract, analyze, display and store the information. Thereby, immediate detection of a person falling asleep is made feasible and, tracking the sleep cycle continuously provides an insight about the fatigue level. This approach of using a wireless, real time, dry sensor on a flexible substrate mitigates obtrusiveness that is expected from a wearable system. We have previously presented the results of the aforementioned wearable systems. This paper aims to extend our work conceptually through a review of engineering and medical techniques involved in wearable systems to detect drowsiness.